Protection of extreme ultraviolet lithography masks. II. Showerhead flow mitigation of nanoscale particulate contamination [Protection of EUV lithography masks II: Showerhead flow mitigation of nanoscale particulate contamination

DOE PAGES

Klebanoff, Leonard E.; Torczynski, John R.; Geller, Anthony S.; ...

2015-03-27

An analysis is presented of a method to protect the reticle (mask) in an extreme ultraviolet (EUV) mask inspection tool using a showerhead plenum to provide a continuous flow of clean gas over the surface of a reticle. The reticle is suspended in an inverted fashion (face down) within a stage/holder that moves back and forth over the showerhead plenum as the reticle is inspected. It is essential that no particles of 10-nm diameter or larger be deposited on the reticle during inspection. Particles can originate from multiple sources in the system, and mask protection from each source is explicitlymore » analyzed. The showerhead plate has an internal plenum with a solid conical wall isolating the aperture. The upper and lower surfaces of the plate are thin flat sheets of porous-metal material. These porous sheets form the top and bottom showerheads that supply the region between the showerhead plate and the reticle and the region between the conical aperture and the Optics Zone box with continuous flows of clean gas. The model studies show that the top showerhead provides robust reticle protection from particles of 10-nm diameter or larger originating from the Reticle Zone and from plenum surfaces contaminated by exposure to the Reticle Zone. Protection is achieved with negligible effect on EUV transmission. Furthermore, the bottom showerhead efficiently protects the reticle from nanoscale particles originating from the Optics Zone.« less

Effect of SPM-based cleaning POR on EUV mask performance

NASA Astrophysics Data System (ADS)

Choi, Jaehyuck; Lee, Han-shin; Yoon, Jinsang; Shimomura, Takeya; Friz, Alex; Montgomery, Cecilia; Ma, Andy; Goodwin, Frank; Kang, Daehyuk; Chung, Paul; Shin, Inkyun; Cho, H.

2011-11-01

EUV masks include many different layers of various materials rarely used in optical masks, and each layer of material has a particular role in enhancing the performance of EUV lithography. Therefore, it is crucial to understand how the mask quality and patterning performance can change during mask fabrication, EUV exposure, maintenance cleaning, shipping, or storage. The fact that a pellicle is not used to protect the mask surface in EUV lithography suggests that EUV masks may have to undergo more cleaning cycles during their lifetime. More frequent cleaning, combined with the adoption of new materials for EUV masks, necessitates that mask manufacturers closely examine the performance change of EUV masks during cleaning process. We have investigated EUV mask quality and patterning performance during 30 cycles of Samsung's EUV mask SPM-based cleaning and 20 cycles of SEMATECH ADT exposure. We have observed that the quality and patterning performance of EUV masks does not significantly change during these processes except mask pattern CD change. To resolve this issue, we have developed an acid-free cleaning POR and substantially improved EUV mask film loss compared to the SPM-based cleaning POR.

Film loss-free cleaning chemicals for EUV mask lifetime elongation developed through combinatorial chemical screening

NASA Astrophysics Data System (ADS)

Choi, Jaehyuck; Kim, Jinsu; Lowe, Jeff; Dattilo, Davide; Koh, Soowan; Choi, Jun Yeol; Dietze, Uwe; Shoki, Tsutomu; Kim, Byung Gook; Jeon, Chan-Uk

2015-10-01

EUV masks include many different layers of various materials rarely used in optical masks, and each layer of material has a particular role in enhancing the performance of EUV lithography. Therefore, it is crucial to understand how the mask quality and patterning performance can change during mask fabrication, EUV exposure, maintenance cleaning, shipping, or storage. SPM (Sulfuric acid peroxide mixture) which has been extensively used for acid cleaning of photomask and wafer has serious drawback for EUV mask cleaning. It shows severe film loss of tantalum-based absorber layers and limited removal efficiency of EUV-generated carbon contaminants on EUV mask surface. Here, we introduce such novel cleaning chemicals developed for EUV mask as almost film loss free for various layers of the mask and superior carbon removal performance. Combinatorial chemical screening methods allowed us to screen several hundred combinations of various chemistries and additives under several different process conditions of temperature and time, eventually leading to development of the best chemistry selections for EUV mask cleaning. Recently, there have been many activities for the development of EUV pellicle, driven by ASML and core EUV scanner customer companies. It is still important to obtain film-loss free cleaning chemicals because cleaning cycle of EUV mask should be much faster than that of optic mask mainly due to EUV pellicle lifetime. More frequent cleaning, combined with the adoption of new materials for EUV masks, necessitates that mask manufacturers closely examine the performance change of EUV masks during cleaning process. We have investigated EUV mask quality changes and film losses during 50 cleaning cycles using new chemicals as well as particle and carbon contaminant removal characteristics. We have observed that the performance of new chemicals developed is superior to current SPM or relevant cleaning chemicals for EUV mask cleaning and EUV mask lifetime elongation.

Extreme ultraviolet patterned mask inspection performance of advanced projection electron microscope system for 11nm half-pitch generation

NASA Astrophysics Data System (ADS)

Hirano, Ryoichi; Iida, Susumu; Amano, Tsuyoshi; Watanabe, Hidehiro; Hatakeyama, Masahiro; Murakami, Takeshi; Suematsu, Kenichi; Terao, Kenji

2016-03-01

Novel projection electron microscope optics have been developed and integrated into a new inspection system named EBEYE-V30 ("Model EBEYE" is an EBARA's model code) , and the resulting system shows promise for application to half-pitch (hp) 16-nm node extreme ultraviolet lithography (EUVL) patterned mask inspection. To improve the system's inspection throughput for 11-nm hp generation defect detection, a new electron-sensitive area image sensor with a high-speed data processing unit, a bright and stable electron source, and an image capture area deflector that operates simultaneously with the mask scanning motion have been developed. A learning system has been used for the mask inspection tool to meet the requirements of hp 11-nm node EUV patterned mask inspection. Defects are identified by the projection electron microscope system using the "defectivity" from the characteristics of the acquired image. The learning system has been developed to reduce the labor and costs associated with adjustment of the detection capability to cope with newly-defined mask defects. We describe the integration of the developed elements into the inspection tool and the verification of the designed specification. We have also verified the effectiveness of the learning system, which shows enhanced detection capability for the hp 11-nm node.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naulleau, Patrick; Mochi, Iacopo; Goldberg, Kenneth A.

Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modelingmore » software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes rou tinely used in the synchrotron community.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naulleau, Patrick P.; Mochi, Iacopo; Goldberg, Kenneth A.

Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modelingmore » software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes routinely used in the synchrotron community.« less

High brightness electrodeless Z-Pinch EUV source for mask inspection tools

NASA Astrophysics Data System (ADS)

Horne, Stephen F.; Partlow, Matthew J.; Gustafson, Deborah S.; Besen, Matthew M.; Smith, Donald K.; Blackborow, Paul A.

2012-03-01

Energetiq Technology has been shipping the EQ-10 Electrodeless Z-pinchTM light source since 1995. The source is currently being used for metrology, mask inspection, and resist development. Energetiq's higher brightness source has been selected as the source for pre-production actinic mask inspection tools. This improved source enables the mask inspection tool suppliers to build prototype tools with capabilities of defect detection and review down to 16nm design rules. In this presentation we will present new source technology being developed at Energetiq to address the critical source brightness issue. The new technology will be shown to be capable of delivering brightness levels sufficient to meet the HVM requirements of AIMS and ABI and potentially API tools. The basis of the source technology is to use the stable pinch of the electrodeless light source and have a brightness of up to 100W/mm(carat)2-sr. We will explain the source design concepts, discuss the expected performance and present the modeling results for the new design.

Effective EUVL mask cleaning technology solutions for mask manufacturing and in-fab mask maintenance

NASA Astrophysics Data System (ADS)

Dietze, Uwe; Dress, Peter; Waehler, Tobias; Singh, Sherjang; Jonckheere, Rik; Baudemprez, Bart

2011-03-01

Extreme Ultraviolet Lithography (EUVL) is considered the leading lithography technology choice for semiconductor devices at 16nm HP node and beyond. However, before EUV Lithography can enter into High Volume Manufacturing (HVM) of advanced semiconductor devices, the ability to guarantee mask integrity at point-of-exposure must be established. Highly efficient, damage free mask cleaning plays a critical role during the mask manufacturing cycle and throughout the life of the mask, where the absence of a pellicle to protect the EUV mask increases the risk of contamination during storage, handling and use. In this paper, we will present effective EUVL mask cleaning technology solutions for mask manufacturing and in-fab mask maintenance, which employs an intelligent, holistic approach to maximize Mean Time Between Cleans (MBTC) and extend the useful life span of the reticle. The data presented will demonstrate the protection of the capping and absorber layers, preservation of pattern integrity as well as optical and mechanical properties to avoid unpredictable CD-linewidth and overlay shifts. Experiments were performed on EUV blanks and pattern masks using various process conditions. Conditions showing high particle removal efficiency (PRE) and minimum surface layer impact were then selected for durability studies. Surface layer impact was evaluated over multiple cleaning cycles by means of UV reflectivity metrology XPS analysis and wafer prints. Experimental results were compared to computational models. Mask life time predictions where made using the same computational models. The paper will provide a generic overview of the cleaning sequence which yielded best results, but will also provide recommendations for an efficient in-fab mask maintenance scheme, addressing handling, storage, cleaning and inspection.

Three-dimensional characterization of extreme ultraviolet mask blank defects by interference contrast photoemission electron microscopy.

PubMed

Lin, Jingquan; Weber, Nils; Escher, Matthias; Maul, Jochen; Han, Hak-Seung; Merkel, Michael; Wurm, Stefan; Schönhense, Gerd; Kleineberg, Ulf

2008-09-29

A photoemission electron microscope based on a new contrast mechanism "interference contrast" is applied to characterize extreme ultraviolet lithography mask blank defects. Inspection results show that positioning of interference destructive condition (node of standing wave field) on surface of multilayer in the local region of a phase defect is necessary to obtain best visibility of the defect on mask blank. A comparative experiment reveals superiority of the interference contrast photoemission electron microscope (Extreme UV illumination) over a topographic contrast one (UV illumination with Hg discharge lamp) in detecting extreme ultraviolet mask blank phase defects. A depth-resolved detection of a mask blank defect, either by measuring anti-node peak shift in the EUV-PEEM image under varying inspection wavelength condition or by counting interference fringes with a fixed illumination wavelength, is discussed.

Clean induced feature CD shift of EUV mask

NASA Astrophysics Data System (ADS)

Nesládek, Pavel; Schedel, Thorsten; Bender, Markus

2016-05-01

EUV developed in the last decade to the most promising <7nm technology candidate. Defects are considered to be one of the most critical issues of the EUV mask. There are several contributors which make the EUV mask so different from the optical one. First one is the significantly more complicated mask stack consisting currently of 40 Mo/Si double layers, covered by Ru capping layer and TaN/TaO absorber/anti-reflective coating on top of the front face of the mask. Backside is in contrary to optical mask covered as well by conductive layer consisting of Cr or CrN. Second contributor is the fact that EUV mask is currently in contrary to optical mask not yet equipped with sealed pellicle, leading to much higher risk of mask contamination. Third reason is use of EUV mask in vacuum, possibly leading to deposition of vacuum contaminants on the EUV mask surface. Latter reason in combination with tight requirements on backside cleanliness lead to the request of frequent recleaning of the EUV mask, in order to sustain mask lifetime similar to that of optical mask. Mask cleaning process alters slightly the surface of any mask - binary COG mask, as well as phase shift mask of any type and naturally also of the EUV mask as well. In case of optical masks the changes are almost negligible, as the mask is exposed to max. 10-20 re-cleans within its life time. These modifications can be expressed in terms of different specified parameters, e.g. CD shift, phase/trans shift, change of the surface roughness etc. The CD shift, expressed as thinning (or exceptionally thickening) of the dark features on the mask is typically in order of magnitude 0.1nm per process run, which is completely acceptable for optical mask. Projected on the lifetime of EUV mask, assuming 100 clean process cycles, this will lead to CD change of about 10nm. For this reason the requirements for EUV mask cleaning are significantly tighter, << 0.1 nm per process run. This task will look even more challenging, when considering, that the tools for CD measurement at the EUV mask are identical as for optical mask. There is one aspect influencing the CD shift, which demands attention. The mask composition of the EUV mask is significantly different from the optical mask. More precisely there are 2 materials influencing the estimated CD in case of EUV mask, whereas there is one material only in case of optical masks, in first approximation. For optical masks, the CD changes can be attributed to modification of the absorber/ARC layer, as the quartz substrate can be hardly modified by the wet process. For EUV Masks chemical modification of the Ru capping layer - thinning, oxidization etc. are rather more probable and we need to take into account, how this effects can influence the CD measurement process. CD changes measured can be interpreted as either change in the feature size, or modification of the chemical nature of both absorber/ARC layer stack and the Ru capping layer. In our work we try to separate the effect of absorber and Ru/capping layer on the CD shift observed and propose independent way of estimation both parameters.

Shot-noise limited throughput of soft x-ray ptychography for nanometrology applications

NASA Astrophysics Data System (ADS)

Koek, Wouter; Florijn, Bastiaan; Bäumer, Stefan; Kruidhof, Rik; Sadeghian, Hamed

2018-03-01

Due to its potential for high resolution and three-dimensional imaging, soft x-ray ptychography has received interest for nanometrology applications. We have analyzed the measurement time per unit area when using soft x-ray ptychography for various nanometrology applications including mask inspection and wafer inspection, and are thus able to predict (order of magnitude) throughput figures. Here we show that for a typical measurement system, using a typical sampling strategy, and when aiming for 10-15 nm resolution, it is expected that a wafer-based topology (2.5D) measurement takes approximately 4 minutes per μm2 , and a full three-dimensional measurement takes roughly 6 hours per μm2 . Due to their much higher reflectivity EUV masks can be measured considerably faster; a measurement speed of 0.1 seconds per μm2 is expected. However, such speeds do not allow for full wafer or mask inspection at industrially relevant throughput.

NXE pellicle: offering a EUV pellicle solution to the industry

NASA Astrophysics Data System (ADS)

Brouns, Derk; Bendiksen, Aage; Broman, Par; Casimiri, Eric; Colsters, Paul; Delmastro, Peter; de Graaf, Dennis; Janssen, Paul; van de Kerkhof, Mark; Kramer, Ronald; Kruizinga, Matthias; Kuntzel, Henk; van der Meulen, Frits; Ockwell, David; Peter, Maria; Smith, Daniel; Verbrugge, Beatrijs; van de Weg, David; Wiley, Jim; Wojewoda, Noelie; Zoldesi, Carmen; van Zwol, Pieter

2016-03-01

Towards the end of 2014, ASML committed to provide a EUV pellicle solution to the industry. Last year, during SPIE Microlithography 2015, we introduced the NXE pellicle concept, a removable pellicle solution that is compatible with current and future patterned mask inspection methods. This paper shows results of how we took this concept to a complete EUV pellicle solution for the industry. We will highlight some technical design challenges we faced developing the NXE pellicle and how we solved them. We will also present imaging results of pellicle exposures on a 0.33 NA NXE scanner system. In conjunction with the NXE pellicle, we will also present the supporting tooling we have developed to enable pellicle use.

Observation of EUVL mask using coherent EUV scatterometry microscope with high-harmonic-generation EUV source

NASA Astrophysics Data System (ADS)

Mamezaki, Daiki; Harada, Tetsuo; Nagata, Yutaka; Watanabe, Takeo

2017-07-01

In extreme ultraviolet (EUV) lithography, development of review tools for EUV mask pattern and phase defect at working wavelength of 13.5 nm is required. The EUV mask is composed of an absorber pattern (50 - 70 nm thick) and Mo/Si multilayer (280 nm thick) on a glass substrate. This mask pattern seems three-dimensional (3D) structure. This 3D structure would modulate EUV reflection phase, which would cause focus and pattern shifts. Thus, EUV phase imaging is important to evaluate this phase modulation. We have developed coherent EUV scatterometry microscope (CSM), which is a simple microscope without objective optics. EUV phase and intensity image are reconstructed with diffraction images by ptychography with coherent EUV illumination. The high-harmonic-generation (HHG) EUV source was employed for standalone CSM system. In this study, we updated HHG system of pump-laser reduction and gas-pressure control. Two types of EUV mask absorber patterns were observed. An 88-nm lines-and-spaces and a cross-line patterns were clearly reconstructed by ptychography. In addition, a natural defect with 2-μm diameter on the cross-line was well reconstructed. This demonstrated the high capability of the standalone CSM, which system will be used in the factories, such as mask shops and semiconductor fabrication plants.

Results from prototype die-to-database reticle inspection system

NASA Astrophysics Data System (ADS)

Mu, Bo; Dayal, Aditya; Broadbent, Bill; Lim, Phillip; Goonesekera, Arosha; Chen, Chunlin; Yeung, Kevin; Pinto, Becky

2009-03-01

A prototype die-to-database high-resolution reticle defect inspection system has been developed for 32nm and below logic reticles, and 4X Half Pitch (HP) production and 3X HP development memory reticles. These nodes will use predominantly 193nm immersion lithography (with some layers double patterned), although EUV may also be used. Many different reticle types may be used for these generations including: binary (COG, EAPSM), simple tritone, complex tritone, high transmission, dark field alternating (APSM), mask enhancer, CPL, and EUV. Finally, aggressive model based OPC is typically used, which includes many small structures such as jogs, serifs, and SRAF (sub-resolution assist features), accompanied by very small gaps between adjacent structures. The architecture and performance of the prototype inspection system is described. This system is designed to inspect the aforementioned reticle types in die-todatabase mode. Die-to-database inspection results are shown on standard programmed defect test reticles, as well as advanced 32nm logic, and 4X HP and 3X HP memory reticles from industry sources. Direct comparisons with currentgeneration inspection systems show measurable sensitivity improvement and a reduction in false detections.

EUV mask manufacturing readiness in the merchant mask industry

NASA Astrophysics Data System (ADS)

Green, Michael; Choi, Yohan; Ham, Young; Kamberian, Henry; Progler, Chris; Tseng, Shih-En; Chiou, Tsann-Bim; Miyazaki, Junji; Lammers, Ad; Chen, Alek

2017-10-01

As nodes progress into the 7nm and below regime, extreme ultraviolet lithography (EUVL) becomes critical for all industry participants interested in remaining at the leading edge. One key cost driver for EUV in the supply chain is the reflective EUV mask. As of today, the relatively few end users of EUV consist primarily of integrated device manufactures (IDMs) and foundries that have internal (captive) mask manufacturing capability. At the same time, strong and early participation in EUV by the merchant mask industry should bring value to these chip makers, aiding the wide-scale adoption of EUV in the future. For this, merchants need access to high quality, representative test vehicles to develop and validate their own processes. This business circumstance provides the motivation for merchants to form Joint Development Partnerships (JDPs) with IDMs, foundries, Original Equipment Manufacturers (OEMs) and other members of the EUV supplier ecosystem that leverage complementary strengths. In this paper, we will show how, through a collaborative supplier JDP model between a merchant and OEM, a novel, test chip driven strategy is applied to guide and validate mask level process development. We demonstrate how an EUV test vehicle (TV) is generated for mask process characterization in advance of receiving chip maker-specific designs. We utilize the TV to carry out mask process "stress testing" to define process boundary conditions which can be used to create Mask Rule Check (MRC) rules as well as serve as baseline conditions for future process improvement. We utilize Advanced Mask Characterization (AMC) techniques to understand process capability on designs of varying complexity that include EUV OPC models with and without sub-resolution assist features (SRAFs). Through these collaborations, we demonstrate ways to develop EUV processes and reduce implementation risks for eventual mass production. By reducing these risks, we hope to expand access to EUV mask capability for the broadest community possible as the technology is implemented first within and then beyond the initial early adopters.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Upadhyaya, Mihir; Jindal, Vibhu; Basavalingappa, Adarsh

The availability of defect-free masks is considered to be a critical issue for enabling extreme ultraviolet lithography (EUVL) as the next generation technology. Since completely defect-free masks will be hard to achieve, it is essential to have a good understanding of the printability of the native EUV mask defects. In this work, we performed a systematic study of native mask defects to understand the defect printability caused by them. The multilayer growth over native substrate mask blank defects was correlated to the multilayer growth over regular-shaped defects having similar profiles in terms of their width and height. To model themore » multilayer growth over the defects, a novel level-set multilayer growth model was used that took into account the tool deposition conditions of the Veeco Nexus ion beam deposition tool. The same tool was used for performing the actual deposition of the multilayer stack over the characterized native defects, thus ensuring a fair comparison between the actual multilayer growth over native defects, and modeled multilayer growth over regular-shaped defects. Further, the printability of the characterized native defects was studied with the SEMATECH-Berkeley Actinic Inspection Tool (AIT), an EUV mask-imaging microscope at Lawrence Berkeley National Laboratory (LBNL). Printability of the modeled regular-shaped defects, which were propagated up the multilayer stack using level-set growth model was studied using defect printability simulations implementing the waveguide algorithm. Good comparison was observed between AIT and the simulation results, thus demonstrating that multilayer growth over a defect is primarily a function of a defect’s width and height, irrespective of its shape. This would allow us to predict printability of the arbitrarily-shaped native EUV mask defects in a systematic and robust manner.« less

Improvements in the EQ-10 electrodeless Z-pinch EUV source for metrology applications

NASA Astrophysics Data System (ADS)

Horne, Stephen F.; Gustafson, Deborah; Partlow, Matthew J.; Besen, Matthew M.; Smith, Donald K.; Blackborow, Paul A.

2011-04-01

Now that EUV lithography systems are beginning to ship into the fabs for next generation chips it is more critical that the EUV infrastructure developments are keeping pace. Energetiq Technology has been shipping the EQ-10 Electrodeless Z-pinch™ light source since 2005. The source is currently being used for metrology, mask inspection, and resist development. These applications require especially stable performance in both power and source size. Over the last 5 years Energetiq has made many source modifications which have included better thermal management as well as high pulse rate operation6. Recently we have further increased the system power handling and electrical pulse reproducibility. The impact of these modifications on source performance will be reported.

EUVL masks: paving the path for commercialization

NASA Astrophysics Data System (ADS)

Mangat, Pawitter J. S.; Hector, Scott D.

2001-09-01

Optical projection lithography has been the principal vehicle of semiconductor manufacturing for more than 20 years and is marching aggressively to satisfy the needs of semiconductor manufacturers for 100nm devices. However, the complexity of optical lithography continues to increase as wavelength reduction continues to 157nm. Extreme Ultraviolet Lithography (EUVL), with wavelength from 13-14 nm, is evolving as a leading next generation lithography option for semiconductor industry to stay on the path laid by Moore's Law. Masks are a critical part of the success of any technology and are considered to be high risk both for optical lithography and NGL technologies for sub-100nm lithography. Two key areas of EUV mask fabrication are reflective multilayer deposition and absorber patterning. In the case of reflective multilayers, delivering defect free multilayers for mask blanks is the biggest challenge. Defect mitigation is being explored as a possible option to smooth the multilayer defects in addition to optimization of the deposition process to reduce defect density. The mask patterning process needs focus on the defect-free absorber stack patterning process, mask cleaning, inspection and repair. In addition, there is considerable effort to understand by simulations, the defect printability, thermal and mechanical distortions, and non-telecentric illumination, to mention a few. To protect the finished mask from defects added during use, a removable pellicle strategy combined with thermophoretic protection during exposure is being developed. Recent migration to square form factor using low thermal expansion material (LTEM) is advantageous as historical developments in optical masks can be applied to EUV mask patterning. This paper addresses recent developments in the EUV mask patterning and highlights critical manufacturing process controls needed to fabricate defect-free full field masks with CD and image placement specifications for sub-70nm node lithography. No technology can be implemented without establishing the commercial infrastructure. The rising cost seems to be a major issue affecting the technology development. With respect to mask fabrication for commercial availability, a virtual mask shop analysis is presented that indicates that the process cost for EUVL masks are comparable to the high end optical mask with a reasonable yield. However, the cost for setting up a new mask facility is considerably high.

Mask process correction (MPC) modeling and its application to EUV mask for electron beam mask writer EBM-7000

NASA Astrophysics Data System (ADS)

Kamikubo, Takashi; Ohnishi, Takayuki; Hara, Shigehiro; Anze, Hirohito; Hattori, Yoshiaki; Tamamushi, Shuichi; Bai, Shufeng; Wang, Jen-Shiang; Howell, Rafael; Chen, George; Li, Jiangwei; Tao, Jun; Wiley, Jim; Kurosawa, Terunobu; Saito, Yasuko; Takigawa, Tadahiro

2010-09-01

In electron beam writing on EUV mask, it has been reported that CD linearity does not show simple signatures as observed with conventional COG (Cr on Glass) masks because they are caused by scattered electrons form EUV mask itself which comprises stacked heavy metals and thick multi-layers. To resolve this issue, Mask Process Correction (MPC) will be ideally applicable. Every pattern is reshaped in MPC. Therefore, the number of shots would not increase and writing time will be kept within reasonable range. In this paper, MPC is extended to modeling for correction of CD linearity errors on EUV mask. And its effectiveness is verified with simulations and experiments through actual writing test.

Implementation of assist features in EUV lithography

NASA Astrophysics Data System (ADS)

Jiang, Fan; Burkhardt, Martin; Raghunathan, Ananthan; Torres, Andres; Gupta, Rachit; Word, James

2015-03-01

The introduction of EUV lithography will happen at a critical feature pitch which corresponds to a k1 factor of roughly 0.45. While this number seems not very aggressive compared to recent ArF lithography nodes, the number is sufficiently low that the introduction of assist features has to be considered. While the small NA makes the k1 factor larger, the depth of focus still needs to be scaled down with wavelength. However the exposure tool's focus control is not greatly improved over the ArF tools, so other solutions to improve the depth of focus, e.g. SRAFs, are needed. On the other hand, sub-resolution assist features (SRAFs) require very small mask dimensions, which make masks more costly to write and inspect. Another disadvantage of SRAFs is the fact that they may cause pattern-dependent best focus shift due to thick mask effects. Those effects can be predicted, but the shift of best focus and the associated tilt of Bossung curves make the process more difficult to control. We investigate the impact of SRAFs on printing in EUV lithography and evaluate advantages and disadvantages. By using image quality parameters such as best focus (BF), and depth of focus (DOF), respectively with and without SRAFs, we will answer the question if we can gain a net benefit for 1D and 2D patterns by adding SRAFs. SRAFs will only be introduced if any net improvement in process variation (PV) outweighs the additional expense of assist patterning on the mask. In this paper, we investigate the difference in printing behavior of symmetric and asymmetric SRAF placement and whether through slit effect needs to be considered in SRAF placement for EUV lithography.

Mask technology for EUV lithography

NASA Astrophysics Data System (ADS)

Bujak, M.; Burkhart, Scott C.; Cerjan, Charles J.; Kearney, Patrick A.; Moore, Craig E.; Prisbrey, Shon T.; Sweeney, Donald W.; Tong, William M.; Vernon, Stephen P.; Walton, Christopher C.; Warrick, Abbie L.; Weber, Frank J.; Wedowski, Marco; Wilhelmsen, Karl C.; Bokor, Jeffrey; Jeong, Sungho; Cardinale, Gregory F.; Ray-Chaudhuri, Avijit K.; Stivers, Alan R.; Tejnil, Edita; Yan, Pei-yang; Hector, Scott D.; Nguyen, Khanh B.

1999-04-01

Extreme UV Lithography (EUVL) is one of the leading candidates for the next generation lithography, which will decrease critical feature size to below 100 nm within 5 years. EUVL uses 10-14 nm light as envisioned by the EUV Limited Liability Company, a consortium formed by Intel and supported by Motorola and AMD to perform R and D work at three national laboratories. Much work has already taken place, with the first prototypical cameras operational at 13.4 nm using low energy laser plasma EUV light sources to investigate issues including the source, camera, electro- mechanical and system issues, photoresists, and of course the masks. EUV lithograph masks are fundamentally different than conventional photolithographic masks as they are reflective instead of transmissive. EUV light at 13.4 nm is rapidly absorbed by most materials, thus all light transmission within the EUVL system from source to silicon wafer, including EUV reflected from the mask, is performed by multilayer mirrors in vacuum.

Registration performance on EUV masks using high-resolution registration metrology

NASA Astrophysics Data System (ADS)

Steinert, Steffen; Solowan, Hans-Michael; Park, Jinback; Han, Hakseung; Beyer, Dirk; Scherübl, Thomas

2016-10-01

Next-generation lithography based on EUV continues to move forward to high-volume manufacturing. Given the technical challenges and the throughput concerns a hybrid approach with 193 nm immersion lithography is expected, at least in the initial state. Due to the increasing complexity at smaller nodes a multitude of different masks, both DUV (193 nm) and EUV (13.5 nm) reticles, will then be required in the lithography process-flow. The individual registration of each mask and the resulting overlay error are of crucial importance in order to ensure proper functionality of the chips. While registration and overlay metrology on DUV masks has been the standard for decades, this has yet to be demonstrated on EUV masks. Past generations of mask registration tools were not necessarily limited in their tool stability, but in their resolution capabilities. The scope of this work is an image placement investigation of high-end EUV masks together with a registration and resolution performance qualification. For this we employ a new generation registration metrology system embedded in a production environment for full-spec EUV masks. This paper presents excellent registration performance not only on standard overlay markers but also on more sophisticated e-beam calibration patterns.

Printability and inspectability of programmed pit defects on teh masks in EUV lithography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, I.-Y.; Seo, H.-S.; Ahn, B.-S.

2010-03-12

Printability and inspectability of phase defects in ELlVL mask originated from substrate pit were investigated. For this purpose, PDMs with programmed pits on substrate were fabricated using different ML sources from several suppliers. Simulations with 32-nm HP L/S show that substrate pits with below {approx}20 nm in depth would not be printed on the wafer if they could be smoothed by ML process down to {approx}1 nm in depth on ML surface. Through the investigation of inspectability for programmed pits, minimum pit sizes detected by KLA6xx, AIT, and M7360 depend on ML smoothing performance. Furthermore, printability results for pit defectsmore » also correlate with smoothed pit sizes. AIT results for pattemed mask with 32-nm HP L/S represents that minimum printable size of pits could be {approx}28.3 nm of SEVD. In addition, printability of pits became more printable as defocus moves to (-) directions. Consequently, printability of phase defects strongly depends on their locations with respect to those of absorber patterns. This indicates that defect compensation by pattern shift could be a key technique to realize zero printable phase defects in EUVL masks.« less

A new mask exposure and analysis facility

NASA Astrophysics Data System (ADS)

te Sligte, Edwin; Koster, Norbert; Deutz, Alex; Staring, Wilbert

2014-10-01

The introduction of ever higher source powers in EUV systems causes increased risks for contamination and degradation of EUV masks and pellicles. Appropriate testing can help to inventory and mitigate these risks. To this end, we propose EBL2: a laboratory EUV exposure system capable of operating at high EUV powers and intensities, and capable of exposing and analyzing EUV masks. The proposed system architecture is similar to the EBL system which has been operated jointly by TNO and Carl Zeiss SMT since 2005. EBL2 contains an EUV Beam Line, in which samples can be exposed to EUV irradiation in a controlled environment. Attached to this Beam Line is an XPS system, which can be reached from the Beam Line via an in-vacuum transfer system. This enables surface analysis of exposed masks without breaking vacuum. Automated handling with dual pods is foreseen so that exposed EUV masks will still be usable in EUV lithography tools to assess the imaging impact of the exposure. Compared to the existing system, large improvements in EUV power, intensity, reliability, and flexibility are proposed. Also, in-situ measurements by e.g. ellipsometry is foreseen for real time monitoring of the sample condition. The system shall be equipped with additional ports for EUVR or other analysis tools. This unique facility will be open for external customers and other research groups.

NXE pellicle: development update

NASA Astrophysics Data System (ADS)

Brouns, Derk; Bendiksen, Aage; Broman, Par; Casimiri, Eric; Colsters, Paul; de Graaf, Dennis; Harrold, Hilary; Hennus, Piet; Janssen, Paul; Kramer, Ronald; Kruizinga, Matthias; Kuntzel, Henk; Lafarre, Raymond; Mancuso, Andrea; Ockwell, David; Smith, Daniel; van de Weg, David; Wiley, Jim

2016-09-01

ASML introduced the NXE pellicle concept, a removable pellicle solution that is compatible with current and future patterned mask inspection methods. We will present results of how we have taken the idea from concept to a demonstrated solution enabling the use of EUV pellicle by the industry for high volume manufacturing. We will update on the development of the next generation of pellicle films with higher power capability. Further, we will provide an update on top level requirements for pellicles and external interface requirements needed to support NXE pellicle adoption at a mask shop. Finally, we will present ASML's pellicle handling equipment to enable pellicle use at mask shops and our NXE pellicle roadmap outlining future improvements.

Imaging performance improvement of coherent extreme-ultraviolet scatterometry microscope with high-harmonic-generation extreme-ultraviolet source

NASA Astrophysics Data System (ADS)

Mamezaki, Daiki; Harada, Tetsuo; Nagata, Yutaka; Watanabe, Takeo

2017-06-01

In extreme-ultraviolet (EUV) lithography, the development of a review apparatus for the EUV mask pattern at an exposure wavelength of 13.5 nm is required. The EUV mask is composed of an absorber pattern and a Mo/Si multilayer on a glass substrate. This mask pattern has a three-dimensional (3D) structure. The 3D structure would modulate the EUV reflection phase, which would cause focus and pattern shifts. Thus, the review of the EUV phase image is also important. We have developed a coherent EUV scatterometry microscope (CSM), which is a simple microscope without objective optics. The EUV phase and intensity images were reconstructed with diffraction images by ptychography. For a standalone mask review, the high-harmonic-generation (HHG) EUV source was employed. In this study, we updated the sample stage, pump-laser reduction system, and gas-pressure control system to reconstruct the image. As a result, an 88 nm line-and-space pattern and a cross-line pattern were reconstructed. In addition, a particle defect of 2 µm diameter was well reconstructed. This demonstrated the high capability of the standalone CSM, which can hence be used in factories, such as mask shops and semiconductor fabrication plants.

Characterization and control of EUV scanner dose uniformity and stability

NASA Astrophysics Data System (ADS)

Robinson, Chris; Corliss, Dan; Meli, Luciana; Johnson, Rick

2018-03-01

The EUV source is an impressive feat of engineering that provides 13.5 nm radiation by vaporizing tin droplets with a high power CO2 laser and focusing the photons produced in the resultant plasma into the scanner illumination system. Great strides have been made in addressing the many potential stability challenges, but there are still residual spatial and temporal dose non-uniformity signatures. Since even small dose errors can impact the yieldable process window for the advanced lithography products that are exposed on EUV scanners it is crucial to monitor and control the dose variability. Using on-board metrology, the EUV scanner outputs valuable metrics that provide real time insight into the dose performance. We have supplemented scanner data collection with a wafer based methodology that provides high throughput, high sensitivity, quantitative characterization of the EUV scanner dose delivery. The technique uses open frame EUV exposures, so it is exclusive of lithographic pattern imaging, exclusive of lithographic mask pattern and not limited by placement of metrology features. Processed wafers are inspected rapidly, providing 20,000 pixels of detail per exposure field in approximately one minute. Exposing the wafer on the scanner with a bit less than the resist E0 (open frame clearing dose) results in good sensitivity to small variations in the EUV dose delivered. The nominal exposure dose can be modulated by field to calibrate the inspection results and provide quantitative assessment of variations with < 1% sensitivity. This technique has been used for dose uniformity assessments. It is also being used for long term dose stability monitoring and has proven valuable for short term dose stability follow up investigations.

Mask-induced aberration in EUV lithography

NASA Astrophysics Data System (ADS)

Nakajima, Yumi; Sato, Takashi; Inanami, Ryoichi; Nakasugi, Tetsuro; Higashiki, Tatsuhiko

2009-04-01

We estimated aberrations using Zernike sensitivity analysis. We found the difference of the tolerated aberration with line direction for illumination. The tolerated aberration of perpendicular line for illumination is much smaller than that of parallel line. We consider this difference to be attributable to the mask 3D effect. We call it mask-induced aberration. In the case of the perpendicular line for illumination, there was a difference in CD between right line and left line without aberration. In this report, we discuss the possibility of pattern formation in NA 0.25 generation EUV lithography tool. In perpendicular pattern for EUV light, the dominant part of aberration is mask-induced aberration. In EUV lithography, pattern correction based on the mask topography effect will be more important.

Investigating the intrinsic cleanliness of automated handling designed for EUV mask pod-in-pod systems

NASA Astrophysics Data System (ADS)

Brux, O.; van der Walle, P.; van der Donck, J. C. J.; Dress, P.

2011-11-01

Extreme Ultraviolet Lithography (EUVL) is the most promising solution for technology nodes 16nm (hp) and below. However, several unique EUV mask challenges must be resolved for a successful launch of the technology into the market. Uncontrolled introduction of particles and/or contamination into the EUV scanner significantly increases the risk for device yield loss and potentially scanner down-time. With the absence of a pellicle to protect the surface of the EUV mask, a zero particle adder regime between final clean and the point-of-exposure is critical for the active areas of the mask. A Dual Pod concept for handling EUV masks had been proposed by the industry as means to minimize the risk of mask contamination during transport and storage. SuSS-HamaTech introduces MaskTrackPro InSync as a fully automated solution for the handling of EUV masks in and out of this Dual Pod System and therefore constitutes an interface between various tools inside the Fab. The intrinsic cleanliness of each individual handling and storage step of the inner shell (EIP) of this Dual Pod and the EUV mask inside the InSync Tool has been investigated to confirm the capability for minimizing the risk of cross-contamination. An Entegris Dual Pod EUV-1000A-A110 has been used for the qualification. The particle detection for the qualification procedure was executed with the TNO's RapidNano Particle Scanner, qualified for particle sizes down to 50nm (PSL equivalent). It has been shown that the target specification of < 2 particles @ 60nm per 25 cycles has been achieved. In case where added particles were measured, the EIP has been identified as a potential root cause for Ni particle generation. Any direct Ni-Al contact has to be avoided to mitigate the risk of material abrasion.

Efficient analysis of three dimensional EUV mask induced imaging artifacts using the waveguide decomposition method

NASA Astrophysics Data System (ADS)

Shao, Feng; Evanschitzky, Peter; Fühner, Tim; Erdmann, Andreas

2009-10-01

This paper employs the Waveguide decomposition method as an efficient rigorous electromagnetic field (EMF) solver to investigate three dimensional mask-induced imaging artifacts in EUV lithography. The major mask diffraction induced imaging artifacts are first identified by applying the Zernike analysis of the mask nearfield spectrum of 2D lines/spaces. Three dimensional mask features like 22nm semidense/dense contacts/posts, isolated elbows and line-ends are then investigated in terms of lithographic results. After that, the 3D mask-induced imaging artifacts such as feature orientation dependent best focus shift, process window asymmetries, and other aberration-like phenomena are explored for the studied mask features. The simulation results can help lithographers to understand the reasons of EUV-specific imaging artifacts and to devise illumination and feature dependent strategies for their compensation in the optical proximity correction (OPC) for EUV masks. At last, an efficient approach using the Zernike analysis together with the Waveguide decomposition technique is proposed to characterize the impact of mask properties for the future OPC process.

Carbon contamination analysis and its effect on extreme ultra violet mask imaging performance using coherent scattering microscopy/in-situ accelerated contamination system.

PubMed

Jeong, Chang Young; Lee, Sangsul; Doh, Jong Gul; Lee, Jae Uk; Cha, Han-sun; Nichols, William T; Lee, Dong Gun; Kim, Seong Sue; Cho, Han Ku; Rah, Seung-yu; Ahn, Jinho

2011-07-01

The coherent scattering microscopy/in-situ accelerated contamination system (CSM/ICS) is a developmental metrology tool designed to analyze the impact of carbon contamination on the imaging performance. It was installed at 11B EUVL beam-line of the Pohang Accelerator Laboratory (PAL). Monochromatized 13.5 nm wavelength beam with Mo/Si multilayer mirrors and zirconium filters was used. The CSM/ICS is composed of the CSM for measuring imaging properties and the ICS for implementing acceleration of carbon contamination. The CSM has been proposed as an actinic inspection technique that records the coherent diffraction pattern from the EUV mask and reconstructs its aerial image using a phase retrieval algorithm. To improve the CSM measurement accuracy, optical and electrical noises of main chamber were minimized. The background noise level measured by CCD camera was approximately 8.5 counts (3 sigma) when the EUV beam was off. Actinic CD measurement repeatability was <1 A (3 sigma) at 17.5 nm line and space pattern. The influence of carbon contamination on the imaging properties can be analyzed by transferring EUV mask to CSM imaging center position after executing carbon contamination without a fine alignment system. We also installed photodiode and ellipsometry for in-situ reflectivity and thickness measurement. This paper describes optical design and system performance observed during the first phase of integration, including CSM imaging performance and carbon contamination analysis results.

CXRO - Mi-Young Im, Staff Scientist

Science.gov Websites

X-Ray Database Zone Plate Education Nanomagnetism X-Ray Microscopy LDJIM EUV Lithography EUV Mask Publications Contact The Center for X-Ray Optics is a multi-disciplined research group within Lawrence Berkeley -Ray Optics X-Ray Database Nanomagnetism X-Ray Microscopy EUV Lithography EUV Mask Imaging

Results from a new die-to-database reticle inspection platform

NASA Astrophysics Data System (ADS)

Broadbent, William; Xiong, Yalin; Giusti, Michael; Walsh, Robert; Dayal, Aditya

2007-03-01

A new die-to-database high-resolution reticle defect inspection system has been developed for the 45nm logic node and extendable to the 32nm node (also the comparable memory nodes). These nodes will use predominantly 193nm immersion lithography although EUV may also be used. According to recent surveys, the predominant reticle types for the 45nm node are 6% simple tri-tone and COG. Other advanced reticle types may also be used for these nodes including: dark field alternating, Mask Enhancer, complex tri-tone, high transmission, CPL, EUV, etc. Finally, aggressive model based OPC will typically be used which will include many small structures such as jogs, serifs, and SRAF (sub-resolution assist features) with accompanying very small gaps between adjacent structures. The current generation of inspection systems is inadequate to meet these requirements. The architecture and performance of a new die-to-database inspection system is described. This new system is designed to inspect the aforementioned reticle types in die-to-database and die-to-die modes. Recent results from internal testing of the prototype systems are shown. The results include standard programmed defect test reticles and advanced 45nm and 32nm node reticles from industry sources. The results show high sensitivity and low false detections being achieved.

Carbon contamination topography analysis of EUV masks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Y.-J.; Yankulin, L.; Thomas, P.

2010-03-12

The impact of carbon contamination on extreme ultraviolet (EUV) masks is significant due to throughput loss and potential effects on imaging performance. Current carbon contamination research primarily focuses on the lifetime of the multilayer surfaces, determined by reflectivity loss and reduced throughput in EUV exposure tools. However, contamination on patterned EUV masks can cause additional effects on absorbing features and the printed images, as well as impacting the efficiency of cleaning process. In this work, several different techniques were used to determine possible contamination topography. Lithographic simulations were also performed and the results compared with the experimental data.

EUVL mask patterning with blanks from commercial suppliers

NASA Astrophysics Data System (ADS)

Yan, Pei-Yang; Zhang, Guojing; Nagpal, Rajesh; Shu, Emily Y.; Li, Chaoyang; Qu, Ping; Chen, Frederick T.

2004-12-01

Extreme Ultraviolet Lithography (EUVL) reflective mask blank development includes low thermal expansion material fabrication, mask substrate finishing, reflective multi-layer (ML) and capping layer deposition, buffer (optional)/absorber stack deposition, EUV specific metrology, and ML defect inspection. In the past, we have obtained blanks deposited with various layer stacks from several vendors. Some of them are not commercial suppliers. As a result, the blank and patterned mask qualities are difficult to maintain and improve. In this paper we will present the evaluation results of the EUVL mask pattering processes with the complete EUVL mask blanks supplied by the commercial blank supplier. The EUVL mask blanks used in this study consist of either quartz or ULE substrates which is a type of low thermal expansion material (LTEM), 40 pairs of molybdenum/silicon (Mo/Si) ML layer, thin ruthenium (Ru) capping layer, tantalum boron nitride (TaBN) absorber, and chrome (Cr) backside coating. No buffer layer is used. Our study includes the EUVL mask blank characterization, patterned EUVL mask characterization, and the final patterned EUVL mask flatness evaluation.

Advanced EUV mask and imaging modeling

NASA Astrophysics Data System (ADS)

Evanschitzky, Peter; Erdmann, Andreas

2017-10-01

The exploration and optimization of image formation in partially coherent EUV projection systems with complex source shapes requires flexible, accurate, and efficient simulation models. This paper reviews advanced mask diffraction and imaging models for the highly accurate and fast simulation of EUV lithography systems, addressing important aspects of the current technical developments. The simulation of light diffraction from the mask employs an extended rigorous coupled wave analysis (RCWA) approach, which is optimized for EUV applications. In order to be able to deal with current EUV simulation requirements, several additional models are included in the extended RCWA approach: a field decomposition and a field stitching technique enable the simulation of larger complex structured mask areas. An EUV multilayer defect model including a database approach makes the fast and fully rigorous defect simulation and defect repair simulation possible. A hybrid mask simulation approach combining real and ideal mask parts allows the detailed investigation of the origin of different mask 3-D effects. The image computation is done with a fully vectorial Abbe-based approach. Arbitrary illumination and polarization schemes and adapted rigorous mask simulations guarantee a high accuracy. A fully vectorial sampling-free description of the pupil with Zernikes and Jones pupils and an optimized representation of the diffraction spectrum enable the computation of high-resolution images with high accuracy and short simulation times. A new pellicle model supports the simulation of arbitrary membrane stacks, pellicle distortions, and particles/defects on top of the pellicle. Finally, an extension for highly accurate anamorphic imaging simulations is included. The application of the models is demonstrated by typical use cases.

Next generation of Z* modelling tool for high intensity EUV and soft x-ray plasma sources simulations

NASA Astrophysics Data System (ADS)

Zakharov, S. V.; Zakharov, V. S.; Choi, P.; Krukovskiy, A. Y.; Novikov, V. G.; Solomyannaya, A. D.; Berezin, A. V.; Vorontsov, A. S.; Markov, M. B.; Parot'kin, S. V.

2011-04-01

In the specifications for EUV sources, high EUV power at IF for lithography HVM and very high brightness for actinic mask and in-situ inspections are required. In practice, the non-equilibrium plasma dynamics and self-absorption of radiation limit the in-band radiance of the plasma and the usable radiation power of a conventional single unit EUV source. A new generation of the computational code Z* is currently developed under international collaboration in the frames of FP7 IAPP project FIRE for modelling of multi-physics phenomena in radiation plasma sources, particularly for EUVL. The radiation plasma dynamics, the spectral effects of self-absorption in LPP and DPP and resulting Conversion Efficiencies are considered. The generation of fast electrons, ions and neutrals is discussed. Conditions for the enhanced radiance of highly ionized plasma in the presence of fast electrons are evaluated. The modelling results are guiding a new generation of EUV sources being developed at Nano-UV, based on spatial/temporal multiplexing of individual high brightness units, to deliver the requisite brightness and power for both lithography HVM and actinic metrology applications.

Modeling of thermomechanical changes of extreme-ultraviolet mask and their dependence on absorber variation

NASA Astrophysics Data System (ADS)

Ban, Chung-Hyun; Park, Eun-Sang; Park, Jae-Hun; Oh, Hye-Keun

2018-06-01

Thermal and structural deformation of extreme-ultraviolet lithography (EUVL) masks during the exposure process may become important issues as these masks are subject to rigorous image placement and flatness requirements. The reflective masks used for EUVL absorb energy during exposure, and the temperature of the masks rises as a result. This can cause thermomechanical deformation that can reduce the pattern quality. The use of very thick low-thermal-expansion substrate materials (LTEMs) may reduce energy absorption, but they do not completely eliminate mask deformation. Therefore, it is necessary to predict and optimize the effects of energy transferred from the extreme-ultraviolet (EUV) light source and the resultant patterns of structured EUV masks with complex multilayers. Our study shows that heat accumulates in the masks as exposure progresses. It has been found that a higher absorber ratio (pattern density) applied to the patterning of EUV masks exacerbates the problem, especially in masks with more complex patterns.

Understanding EUV mask blank surface roughness induced LWR and associated roughness requirement

NASA Astrophysics Data System (ADS)

Yan, Pei-Yang; Zhang, Guojing; Gullikson, Eric M.; Goldberg, Ken A.; Benk, Markus P.

2015-03-01

Extreme ultraviolet lithography (EUVL) mask multi-layer (ML) blank surface roughness specification historically comes from blank defect inspection tool requirement. Later, new concerns on ML surface roughness induced wafer pattern line width roughness (LWR) arise. In this paper, we have studied wafer level pattern LWR as a function of EUVL mask surface roughness via High-NA Actinic Reticle Review Tool. We found that the blank surface roughness induced LWR at current blank roughness level is in the order of 0.5nm 3σ for NA=0.42 at the best focus. At defocus of ±40nm, the corresponding LWR will be 0.2nm higher. Further reducing EUVL mask blank surface roughness will increase the blank cost with limited benefit in improving the pattern LWR, provided that the intrinsic resist LWR is in the order of 1nm and above.

Magnetron sputtering for the production of EUV mask blanks

NASA Astrophysics Data System (ADS)

Kearney, Patrick; Ngai, Tat; Karumuri, Anil; Yum, Jung; Lee, Hojune; Gilmer, David; Vo, Tuan; Goodwin, Frank

2015-03-01

Ion Beam Deposition (IBD) has been the primary technique used to deposit EUV mask blanks since 1995 when it was discovered it could produce multilayers with few defects. Since that time the IBD technique has been extensively studied and improved and is finally approaching usable defectivities. But in the intervening years, the defectivity of magnetron sputtering has been greatly improved. This paper evaluates the suitability of a modern magnetron tool to produce EUV mask blanks and the ability to support HVM production. In particular we show that the reflectivity and uniformity of these tools are superior to current generation IBD tools, and that the magnetron tools can produce EUV films with defect densities comparable to recent best IBD tool performance. Magnetron tools also offer many advantages in manufacturability and tool throughput; however, challenges remain, including transitioning the magnetron tools from the wafer to mask formats. While work continues on quantifying the capability of magnetron sputtering to meet the mask blank demands of the industry, for the most part the remaining challenges do not require any fundamental improvements to existing technology. Based on the recent results and the data presented in this paper there is a clear indication that magnetron deposition should be considered for the future of EUV mask blank production.

ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

NASA Astrophysics Data System (ADS)

Deep, Prakash; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter

2016-05-01

At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it's imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMSTM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts printability of defects at wafer level and automates the process of defect dispositioning from images captured using high resolution inspection machine. It first eliminates false defects due to registration, focus errors, image capture errors and random noise caused during inspection. For the remaining real defects, actual mask-like contours are generated using the Calibre® ILT solution [1][2], which is enhanced to predict the actual mask contours from high resolution defect images. It enables accurate prediction of defect contours, which is not possible from images captured using inspection machine because some information is already lost due to optical effects. Calibre's simulation engine is used to generate images at wafer level using scanner optical conditions and mask-like contours as input. The tool then analyses simulated images and predicts defect printability. It automatically calculates maximum CD variation and decides which defects are severe to affect patterns on wafer. In this paper, we assess the printability of defects for the mask of advanced technology nodes. In particular, we will compare the recovered mask contours with contours extracted from SEM image of the mask and compare simulation results with AIMSTM for a variety of defects and patterns. The results of printability assessment and the accuracy of comparison are presented in this paper. We also suggest how this method can be extended to predict printability of defects identified on EUV photomasks.

Etched-multilayer phase shifting masks for EUV lithography

DOEpatents

Chapman, Henry N.; Taylor, John S.

2005-04-05

A method is disclosed for the implementation of phase shifting masks for EUV lithography. The method involves directly etching material away from the multilayer coating of the mask, to cause a refractive phase shift in the mask. By etching into the multilayer (for example, by reactive ion etching), rather than depositing extra material on the top of the multilayer, there will be minimal absorption loss associated with the phase shift.

High-radiance LDP source for mask inspection and beam line applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Teramoto, Yusuke; Santos, Bárbara; Mertens, Guido; Kops, Ralf; Kops, Margarete; von Wezyk, Alexander; Bergmann, Klaus; Yabuta, Hironobu; Nagano, Akihisa; Ashizawa, Noritaka; Taniguchi, Yuta; Yamatani, Daiki; Shirai, Takahiro; Kasama, Kunihiko

2017-04-01

High-throughput actinic mask inspection tools are needed as EUVL begins to enter into volume production phase. One of the key technologies to realize such inspection tools is a high-radiance EUV source of which radiance is supposed to be as high as 100 W/mm2/sr. Ushio is developing laser-assisted discharge-produced plasma (LDP) sources. Ushio's LDP source is able to provide sufficient radiance as well as cleanliness, stability and reliability. Radiance behind the debris mitigation system was confirmed to be 120 W/mm2/sr at 9 kHz and peak radiance at the plasma was increased to over 200 W/mm2/sr in the recent development which supports high-throughput, high-precision mask inspection in the current and future technology nodes. One of the unique features of Ushio's LDP source is cleanliness. Cleanliness evaluation using both grazing-incidence Ru mirrors and normal-incidence Mo/Si mirrors showed no considerable damage to the mirrors other than smooth sputtering of the surface at the pace of a few nm per Gpulse. In order to prove the system reliability, several long-term tests were performed. Data recorded during the tests was analyzed to assess two-dimensional radiance stability. In addition, several operating parameters were monitored to figure out which contributes to the radiance stability. The latest model that features a large opening angle was recently developed so that the tool can utilize a large number of debris-free photons behind the debris shield. The model was designed both for beam line application and high-throughput mask inspection application. At the time of publication, the first product is supposed to be in use at the customer site.

Ultra-low roughness magneto-rheological finishing for EUV mask substrates

NASA Astrophysics Data System (ADS)

Dumas, Paul; Jenkins, Richard; McFee, Chuck; Kadaksham, Arun J.; Balachandran, Dave K.; Teki, Ranganath

2013-09-01

EUV mask substrates, made of titania-doped fused silica, ideally require sub-Angstrom surface roughness, sub-30 nm flatness, and no bumps/pits larger than 1 nm in height/depth. To achieve the above specifications, substrates must undergo iterative global and local polishing processes. Magnetorheological finishing (MRF) is a local polishing technique which can accurately and deterministically correct substrate figure, but typically results in a higher surface roughness than the current requirements for EUV substrates. We describe a new super-fine MRF® polishing fluid whichis able to meet both flatness and roughness specifications for EUV mask blanks. This eases the burden on the subsequent global polishing process by decreasing the polishing time, and hence the defectivity and extent of figure distortion.

Challenges of anamorphic high-NA lithography and mask making

NASA Astrophysics Data System (ADS)

Hsu, Stephen D.; Liu, Jingjing

2017-06-01

Chip makers are actively working on the adoption of 0.33 numerical aperture (NA) EUV scanners for the 7-nm and 5-nm nodes (B. Turko, S. L. Carson, A. Lio, T. Liang, M. Phillips, et al., in `Proc. SPIE9776, Extreme Ultraviolet (EUV) Lithography VII', vol. 977602 (2016) doi: 10.1117/12.2225014; A. Lio, in `Proc. SPIE9776, Extreme Ultraviolet (EUV) Lithography VII', vol. 97760V (2016) doi: 10.1117/12.2225017). In the meantime, leading foundries and integrated device manufacturers are starting to investigate patterning options beyond the 5-nm node (O. Wood, S. Raghunathan, P. Mangat, V. Philipsen, V. Luong, et al., in `Proc. SPIE. 9422, Extreme Ultraviolet (EUV) Lithography VI', vol. 94220I (2015) doi: 10.1117/12.2085022). To minimize the cost and process complexity of multiple patterning beyond the 5-nm node, EUV high-NA single-exposure patterning is a preferred method over EUV double patterning (O. Wood, S. Raghunathan, P. Mangat, V. Philipsen, V. Luong, et al., in `Proc. SPIE. 9422, Extreme Ultraviolet (EUV) Lithography VI', vol. 94220I (2015) doi: 10.1117/12.2085022; J. van Schoot, K. van Ingen Schenau, G. Bottiglieri, K. Troost, J. Zimmerman, et al., `Proc. SPIE. 9776, Extreme Ultraviolet (EUV) Lithography VII', vol. 97761I (2016) doi: 10.1117/12.2220150). The EUV high-NA scanner equipped with a projection lens of 0.55 NA is designed to support resolutions below 10 nm. The high-NA system is beneficial for enhancing resolution, minimizing mask proximity correction bias, improving normalized image log slope (NILS), and controlling CD uniformity (CDU). However, increasing NA from 0.33 to 0.55 reduces the depth of focus (DOF) significantly. Therefore, the source mask optimization (SMO) with sub-resolution assist features (SRAFs) are needed to increase DOF to meet the demanding full chip process control requirements (S. Hsu, R. Howell, J. Jia, H.-Y. Liu, K. Gronlund, et al., EUV `Proc. SPIE9048, Extreme Ultraviolet (EUV) Lithography VI', (2015) doi: 10.1117/12.2086074). To ensure no assist feature printing, the assist feature sizes need to be scaled with λ/NA. The extremely small SRAF width (below 25 nm on the reticle) is difficult to fabricate across the full reticle. In this paper, we introduce an innovative `attenuated SRAF' to improve SRAF manufacturability and still maintain the process window benefit. A new mask fabrication process is proposed to use existing mask-making capability to manufacture the attenuated SRAFs. The high-NA EUV system utilizes anamorphic reduction; 4× in the horizontal (slit) direction and 8× in the vertical (scanning) direction (J. van Schoot, K. van Ingen Schenau, G. Bottiglieri, K. Troost, J. Zimmerman, et al., `Proc. SPIE. 9776, Extreme Ultraviolet (EUV) Lithography VII', vol. 97761I (2016) doi: 10.1117/12.2220150; B. Kneer, S. Migura, W. Kaiser, J. T. Neumann, J. van Schoot, in `Proc. SPIE9422, Extreme Ultraviolet (EUV) Lithography VI', vol. 94221G (2015) doi: 10.1117/12.2175488). For an anamorphic system, the magnification has an angular dependency, and thus, familiar mask specifications such as mask error factor (MEF) need to be redefined. Similarly, mask-manufacturing rule check (MRC) needs to consider feature orientation.

Production of EUV mask blanks with low killer defects

NASA Astrophysics Data System (ADS)

Antohe, Alin O.; Kearney, Patrick; Godwin, Milton; He, Long; John Kadaksham, Arun; Goodwin, Frank; Weaver, Al; Hayes, Alan; Trigg, Steve

2014-04-01

For full commercialization, extreme ultraviolet lithography (EUVL) technology requires the availability of EUV mask blanks that are free of defects. This remains one of the main impediments to the implementation of EUV at the 22 nm node and beyond. Consensus is building that a few small defects can be mitigated during mask patterning, but defects over 100 nm (SiO2 equivalent) in size are considered potential "killer" defects or defects large enough that the mask blank would not be usable. The current defect performance of the ion beam sputter deposition (IBD) tool will be discussed and the progress achieved to date in the reduction of large size defects will be summarized, including a description of the main sources of defects and their composition.

Ion beam deposition system for depositing low defect density extreme ultraviolet mask blanks

NASA Astrophysics Data System (ADS)

Jindal, V.; Kearney, P.; Sohn, J.; Harris-Jones, J.; John, A.; Godwin, M.; Antohe, A.; Teki, R.; Ma, A.; Goodwin, F.; Weaver, A.; Teora, P.

2012-03-01

Extreme ultraviolet lithography (EUVL) is the leading next-generation lithography (NGL) technology to succeed optical lithography at the 22 nm node and beyond. EUVL requires a low defect density reflective mask blank, which is considered to be one of the top two critical technology gaps for commercialization of the technology. At the SEMATECH Mask Blank Development Center (MBDC), research on defect reduction in EUV mask blanks is being pursued using the Veeco Nexus deposition tool. The defect performance of this tool is one of the factors limiting the availability of defect-free EUVL mask blanks. SEMATECH identified the key components in the ion beam deposition system that is currently impeding the reduction of defect density and the yield of EUV mask blanks. SEMATECH's current research is focused on in-house tool components to reduce their contributions to mask blank defects. SEMATECH is also working closely with the supplier to incorporate this learning into a next-generation deposition tool. This paper will describe requirements for the next-generation tool that are essential to realize low defect density EUV mask blanks. The goal of our work is to enable model-based predictions of defect performance and defect improvement for targeted process improvement and component learning to feed into the new deposition tool design. This paper will also highlight the defect reduction resulting from process improvements and the restrictions inherent in the current tool geometry and components that are an impediment to meeting HVM quality EUV mask blanks will be outlined.

Novel EUV mask black border suppressing EUV and DUV OoB light reflection

NASA Astrophysics Data System (ADS)

Ito, Shin; Kodera, Yutaka; Fukugami, Norihito; Komizo, Toru; Maruyama, Shingo; Watanabe, Genta; Yoshida, Itaru; Kotani, Jun; Konishi, Toshio; Haraguchi, Takashi

2016-05-01

EUV lithography is the most promising technology for semiconductor device manufacturing of the 10nm node and beyond. The image border is a pattern free dark area around the die on the photomask serving as transition area between the parts of the mask that is shielded from the exposure light by the Reticle Masking (REMA) blades and the die. When printing a die at dense spacing on an EUV scanner, the reflection from the image border overlaps edges of neighboring dies, affecting CD and contrast in this area. This is related to the fact that EUV absorber stack reflects 1-3% of actinic EUV light. To reduce this effect several types of image border with reduced EUV reflectance (<0.05%) have been proposed; such an image border is referred to as a black border. In particular, an etched multilayer type black border was developed; it was demonstrated that CD impact at the edge of a die is strongly reduced with this type of the black border (BB). However, wafer printing result still showed some CD change in the die influenced by the black border reflection. It was proven that the CD shift was caused by DUV Out of Band (OOB) light from the EUV light source. New types of a multilayer etched BB were evaluated and showed a good potential for DUV light suppression. In this study, a novel BB called `Hybrid Black Border' (HBB) has been developed to eliminate EUV and DUV OOB light reflection by applying optical design technique and special micro-fabrication technique. A new test mask with HBB is fabricated without any degradation of mask quality according to the result of CD performance in the main pattern, defectivity and cleaning durability. The imaging performance for N10 imaging structures is demonstrated on NXE:3300B in collaboration with ASML. This result is compared to the imaging results obtained for a mask with the earlier developed BB, and HBB has achieved ~3x improvement; less than 0.2 nm CD changes are observed in the corners of the die. A CD uniformity budget including impact of OOB light in the die edge area is evaluated which shows that the OOB impact from HBB becomes comparable with other CDU contributors in this area. Finally, we state that HBB is a promising technology allowing for CD control at die edges.

Exploring EUV and SAQP pattering schemes at 5nm technology node

NASA Astrophysics Data System (ADS)

Hamed Fatehy, Ahmed; Kotb, Rehab; Lafferty, Neal; Jiang, Fan; Word, James

2018-03-01

For years, Moore's law keeps driving the semiconductors industry towards smaller dimensions and higher density chips with more devices. Earlier, the correlation between exposure source's wave length and the smallest resolvable dimension, mandated the usage of Deep Ultra-Violent (DUV) optical lithography system which has been used for decades to sustain Moore's law, especially when immersion lithography was introduced with 193nm ArF laser sources. As dimensions of devices get smaller beyond Deep Ultra-Violent (DUV) optical resolution limits, the need for Extremely Ultra-Violent (EUV) optical lithography systems was a must. However, EUV systems were still under development at that time for the mass-production in semiconductors industry. Theretofore, Multi-Patterning (MP) technologies was introduced to swirl about DUV optical lithography limitations in advanced nodes beyond minimum dimension (CD) of 20nm. MP can be classified into two main categories; the first one is to split the target itself across multiple masks that give the original target patterns when they are printed. This category includes Double, Triple and Quadruple patterning (DP, TP, and QP). The second category is the Self-Aligned Patterning (SAP) where the target is divided into Mandrel patterns and non-Mandrel patterns. The Mandrel patterns get printed first, then a self-aligned sidewalls are grown around these printed patterns drawing the other non-Mandrel targets, afterword, a cut mask(s) is used to define target's line-ends. This approach contains Self-Aligned-Double Pattering (SADP) and Self-Aligned- Quadruple-Pattering (SAQP). DUV and MP along together paved the way for the industry down to 7nm. However, with the start of development at the 5nm node and the readiness of EUV, the differentiation question is aroused again, which pattering approach should be selected, direct printing using EUV or DUV with MP, or a hybrid flow that contains both DUV-MP and EUV. In this work we are comparing two potential pattering techniques for Back End Of Line (BEOL) metal layers in the 5nm technology node, the first technique is Single Exposure EUV (SE-EUV) with a Direct Patterning EUV lithography process, and the second one is Self-Aligned Quadruple Patterning (SAQP) with a hybrid lithography processes, where the drawn metal target layer is decomposed into a Mandrel mask and Blocks/Cut mask, Mandrel mask is printed using DUV 193i lithography process, while Block/Cut Mask is printed using SE-EUV lithography process. The pros and cons of each technique are quantified based on Edge-Placement-Error (EPE) and Process Variation Band (PVBand) measured at 1D and 2D edges. The layout used in this comparison is a candidate layout for Foundries 5nm process node.

EUV phase-shifting masks and aberration monitors

NASA Astrophysics Data System (ADS)

Deng, Yunfei; Neureuther, Andrew R.

2002-07-01

Rigorous electromagnetic simulation with TEMPEST is used to examine the use of phase-shifting masks in EUV lithography. The effects of oblique incident illumination and mask patterning by ion-mixing of multilayers are analyzed. Oblique incident illumination causes streamers at absorber edges and causes position shifting in aerial images. The diffraction waves between ion-mixed and pristine multilayers are observed. The phase-shifting caused by stepped substrates is simulated and images show that it succeeds in creation of phase-shifting effects. The diffraction process at the phase boundary is also analyzed. As an example of EUV phase-shifting masks, a coma pattern and probe based aberration monitor is simulated and aerial images are formed under different levels of coma aberration. The probe signal rises quickly as coma increases as designed.

Mask characterization for CDU budget breakdown in advanced EUV lithography

NASA Astrophysics Data System (ADS)

Nikolsky, Peter; Strolenberg, Chris; Nielsen, Rasmus; Nooitgedacht, Tjitte; Davydova, Natalia; Yang, Greg; Lee, Shawn; Park, Chang-Min; Kim, Insung; Yeo, Jeong-Ho

2012-11-01

As the ITRS Critical Dimension Uniformity (CDU) specification shrinks, semiconductor companies need to maintain a high yield of good wafers per day and a high performance (and hence market value) of finished products. This cannot be achieved without continuous analysis and improvement of on-product CDU as one of the main drivers for process control and optimization with better understanding of main contributors from the litho cluster: mask, process, metrology and scanner. In this paper we will demonstrate a study of mask CDU characterization and its impact on CDU Budget Breakdown (CDU BB) performed for an advanced EUV lithography with 1D and 2D feature cases. We will show that this CDU contributor is one of the main differentiators between well-known ArFi and new EUV CDU budgeting principles. We found that reticle contribution to intrafield CDU should be characterized in a specific way: mask absorber thickness fingerprints play a role comparable with reticle CDU in the total reticle part of the CDU budget. Wafer CD fingerprints, introduced by this contributor, may or may not compensate variations of mask CD's and hence influence on total mask impact on intrafield CDU at the wafer level. This will be shown on 1D and 2D feature examples in this paper. Also mask stack reflectivity variations should be taken into account: these fingerprints have visible impact on intrafield CDs at the wafer level and should be considered as another contributor to the reticle part of EUV CDU budget. We observed also MEEF-through-field fingerprints in the studied EUV cases. Variations of MEEF may also play a role for the total intrafield CDU and may be taken into account for EUV Lithography. We characterized MEEF-through-field for the reviewed features, the results to be discussed in our paper, but further analysis of this phenomenon is required. This comprehensive approach to characterization of the mask part of EUV CDU characterization delivers an accurate and integral CDU Budget Breakdown per product/process and Litho tool. The better understanding of the entire CDU budget for advanced EUVL nodes achieved by Samsung and ASML helps to extend the limits of Moore's Law and to deliver successful implementation of smaller, faster and smarter chips in semiconductor industry.

Novel EUV mask black border and its impact on wafer imaging

NASA Astrophysics Data System (ADS)

Kodera, Yutaka; Fukugami, Norihito; Komizo, Toru; Watanabe, Genta; Ito, Shin; Yoshida, Itaru; Maruyama, Shingo; Kotani, Jun; Konishi, Toshio; Haraguchi, Takashi

2016-03-01

EUV lithography is the most promising technology for semiconductor device manufacturing of the 10nm node and beyond. The EUV mask is a key element in the lithographic scanner optical path. The image border is a pattern free dark area around the die on the photomask serving as transition area between the parts of the mask that is shielded from the exposure light by the Reticle Masking (REMA) blades and the die. When printing a die at dense spacing on an EUV scanner, the EUV light reflection from the image border overlaps edges of neighboring dies, affecting CD and contrast in this area. To reduce this effect an etched multilayer type black border was developed, and it was demonstrated that CD impact at the edge of a die is strongly reduced with this type of the black border (BB). However, wafer printing result still showed some CD change influenced by the black border reflection. It was proven that the CD shift was caused by DUV Out of Band (OOB) light which is emitted from EUV light source. New types of a multilayer etched BB were evaluated and showed a good potential for DUV light suppression. In this study, a novel black border called Hybrid Black Border has been developed which allows to eliminate EUV and DUV OOB light reflection. Direct measurements of OOB light from HBB and Normal BB are performed on NXE:3300B ASML EUV scanner; it is shown that HBB OOB reflection is 3x lower than that of Normal BB. Finally, we state that HBB is a promising technology allowing for CD control at die edges.

Prospects of DUV OoB suppression techniques in EUV lithography

NASA Astrophysics Data System (ADS)

Park, Chang-Min; Kim, Insung; Kim, Sang-Hyun; Kim, Dong-Wan; Hwang, Myung-Soo; Kang, Soon-Nam; Park, Cheolhong; Kim, Hyun-Woo; Yeo, Jeong-Ho; Kim, Seong-Sue

2014-04-01

Though scaling of source power is still the biggest challenge in EUV lithography (EUVL) technology era, CD and overlay controls for transistor's requirement are also precondition of adopting EUVL in mass production. Two kinds of contributors are identified as risks for CDU and Overlay: Infrared (IR) and deep ultraviolet (DUV) out of band (OOB) radiations from laser produced plasma (LPP) EUV source. IR from plasma generating CO2 laser that causes optics heating and wafer overlay error is well suppressed by introducing grating on collector to diffract IR off the optical axis and is the effect has been confirmed by operation of pre-production tool (NXE3100). EUV and DUV OOB which are reflected from mask black boarder (BB) are root causes of EUV-specific CD error at the boundaries of exposed shots which would result in the problem of CDU out of spec unless sufficiently suppressed. Therefore, control of DUV OOB reflection from the mask BB is one of the key technologies that must be developed prior to EUV mass production. In this paper, quantitative assessment on the advantage and the disadvantage of potential OOB solutions will be discussed. EUV and DUV OOB impacts on wafer CDs are measured from NXE3100 & NXE3300 experiments. Significant increase of DUV OOB impact on CD from NXE3300 compared with NXE3100 is observed. There are three ways of technology being developed to suppress DUV OOB: spectral purity filter (SPF) as a scanner solution, multi-layer etching as a solution on mask, and resist top-coating as a process solution. PROs and CONs of on-scanner, on-mask, and on-resist solution for the mass production of EUV lithography will be discussed.

Mask characterization for critical dimension uniformity budget breakdown in advanced extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

Nikolsky, Peter; Strolenberg, Chris; Nielsen, Rasmus; Nooitgedacht, Tjitte; Davydova, Natalia; Yang, Greg; Lee, Shawn; Park, Chang-Min; Kim, Insung; Yeo, Jeong-Ho

2013-04-01

As the International Technology Roadmap for Semiconductors critical dimension uniformity (CDU) specification shrinks, semiconductor companies need to maintain a high yield of good wafers per day and high performance (and hence market value) of finished products. This cannot be achieved without continuous analysis and improvement of on-product CDU as one of the main drivers for process control and optimization with better understanding of main contributors from the litho cluster: mask, process, metrology and scanner. We will demonstrate a study of mask CDU characterization and its impact on CDU Budget Breakdown (CDU BB) performed for advanced extreme ultraviolet (EUV) lithography with 1D (dense lines) and 2D (dense contacts) feature cases. We will show that this CDU contributor is one of the main differentiators between well-known ArFi and new EUV CDU budgeting principles. We found that reticle contribution to intrafield CDU should be characterized in a specific way: mask absorber thickness fingerprints play a role comparable with reticle CDU in the total reticle part of the CDU budget. Wafer CD fingerprints, introduced by this contributor, may or may not compensate variations of mask CDs and hence influence on total mask impact on intrafield CDU at the wafer level. This will be shown on 1D and 2D feature examples. Mask stack reflectivity variations should also be taken into account: these fingerprints have visible impact on intrafield CDs at the wafer level and should be considered as another contributor to the reticle part of EUV CDU budget. We also observed mask error enhancement factor (MEEF) through field fingerprints in the studied EUV cases. Variations of MEEF may play a role towards the total intrafield CDU and may need to be taken into account for EUV lithography. We characterized MEEF-through-field for the reviewed features, with results herein, but further analysis of this phenomenon is required. This comprehensive approach to quantifying the mask part of the overall EUV CDU contribution helps deliver an accurate and integral CDU BB per product/process and litho tool. The better understanding of the entire CDU budget for advanced EUVL nodes achieved by Samsung and ASML helps extend the limits of Moore's Law and to deliver successful implementation of smaller, faster and smarter chips in semiconductor industry.

Compact 2D OPC modeling of a metal oxide EUV resist for a 7nm node BEOL layer

NASA Astrophysics Data System (ADS)

Lyons, Adam; Rio, David; Lee, Sook; Wallow, Thomas; Delorme, Maxence; Fumar-Pici, Anita; Kocsis, Michael; de Schepper, Peter; Greer, Michael; Stowers, Jason K.; Gillijns, Werner; De Simone, Danilo; Bekaert, Joost

2017-03-01

Inpria has developed a directly patternable metal oxide hard-mask as a high-resolution photoresist for EUV lithography1. In this contribution, we describe a Tachyon 2D OPC full-chip model for an Inpria resist as applied to an N7 BEOL block mask application.

ILT optimization of EUV masks for sub-7nm lithography

NASA Astrophysics Data System (ADS)

Hooker, Kevin; Kuechler, Bernd; Kazarian, Aram; Xiao, Guangming; Lucas, Kevin

2017-06-01

The 5nm and 7nm technology nodes will continue recent scaling trends and will deliver significantly smaller minimum features, standard cell areas and SRAM cell areas vs. the 10nm node. There are tremendous economic pressures to shrink each subsequent technology, though in a cost-effective and performance enhancing manner. IC manufacturers are eagerly awaiting EUV so that they can more aggressively shrink their technology than they could by using complicated MPT. The current 0.33NA EUV tools and processes also have their patterning limitations. EUV scanner lenses, scanner sources, masks and resists are all relatively immature compared to the current lithography manufacturing baseline of 193i. For example, lens aberrations are currently several times larger (as a function of wavelength) in EUV scanners than for 193i scanners. Robustly patterning 16nm L/S fully random logic metal patterns and 40nm pitch random logic rectangular contacts with 0.33NA EUV are tough challenges that will benefit from advanced OPC/RET. For example, if an IC manufacturer can push single exposure device layer resolution 10% tighter using improved ILT to avoid using DPT, there will be a significant cost and process complexity benefit to doing so. ILT is well known to have considerable benefits in finding flexible 193i mask pattern solutions to improve process window, improve 2D CD control, improve resolution in low K1 lithography regime and help to delay the introduction of DPT. However, ILT has not previously been applied to EUV lithography. In this paper, we report on new developments which extend ILT method to EUV lithography and we characterize the benefits seen vs. traditional EUV OPC/RET methods.

Ultimate patterning limits for EUV at 5nm node and beyond

NASA Astrophysics Data System (ADS)

Ali, Rehab Kotb; Hamed Fatehy, Ahmed; Lafferty, Neal; Word, James

2018-03-01

The 5nm technology node introduces more aggressive geometries than previous nodes. In this paper, we are introducing a comprehensive study to examine the pattering limits of EUV at 0.33NA. The study is divided into two main approaches: (A) Exploring pattering limits of Single Exposure EUV Cut/Block mask in Self-Aligned-Multi-Patterning (SAMP) process, and (B) Exploring the pattering limits of a Single Exposure EUV printing of metal Layers. The printability of the resulted OPC masks is checked through a model based manufacturing flow for the two pattering approaches. The final manufactured patterns are quantified by Edge Placement Error (EPE), Process Variation Band (PVBand), soft/hard bridging and pinching, Image Log Slope (ILS) and Common Depth of Focus (CDOF)

Performance of repaired defects and attPSM in EUV multilayer masks

NASA Astrophysics Data System (ADS)

Deng, Yunfei; La Fontaine, Bruno; Neureuther, Andrew R.

2002-12-01

The imaging performance of non-planar topographies in EUV masks for both partially repaired defects and non-planar attenuating phase-shifting masks made with repair treatments are evaluated using rigorous electromagnetic simulation with TEMPEST. Typical topographies produced by treatment techniques in the literature such as removal of top layers and compaction produced by electron-beam heating are considered. Isolated defects on/near the surface repaired by material removal are shown to result in an image intensity within 5% of the clear field value. Deeply buried defects within the multilayer treated by electron-beam heating can be repaired to 3% of the clear field but over repair can result in some degradation. Compaction from a 6.938 nm period to a 6.312 nm period shows a 540° phase-shift and an intensity reduced to about 6% suggesting such a treatment may be used to create attenuated phase-shifting masks for EUV. The quality of the aerial image for such a mask is studied as a function of the lateral transition distance between treated and untreated regions.

Negative-tone imaging with EUV exposure toward 13nm hp

NASA Astrophysics Data System (ADS)

Tsubaki, Hideaki; Nihashi, Wataru; Tsuchihashi, Toru; Yamamoto, Kei; Goto, Takahiro

2016-03-01

Negative-tone imaging (NTI) with EUV exposure has major advantages with respect to line-width roughness (LWR) and resolution due in part to polymer swelling and favorable dissolution mechanics. In NTI process, both resist and organic solvents play important roles in determining lithography performances. The present study describes novel chemically amplified resist materials based on NTI technology with EUV using a specific organic solvents. Lithographic performances of NTI process were described in this paper under exposures using ASML NXE:3300 EUV scanner at imec. It is emphasized that 14 nm hp was nicely resolved under exposure dose of 37 mJ/cm2 without any bridge and collapse, which are attributed to the low swelling character of NTI process. Although 13 nm hp resolution was potentially obtained, a pattern collapse still restricts its resolution in case coating resist film thickness is 40 nm. Dark mask limitation due mainly to mask defectivity issue makes NTI with EUV favorable approach for printing block mask to produce logic circuit. A good resolution of CD-X 21 nm/CD-Y 32 nm was obtained for block mask pattern using NTI with usable process window and dose of 49 mJ/cm2. Minimum resolution now reaches CD-X 17 nm / CD-Y 23 nm for the block. A 21 nm block mask resolution was not affected by exposure dose and explored toward low dose down to 18 mJ/cm2 by reducing quencher loading. In addition, there was a negligible amount of increase in LCDU for isolated dot pattern when decreasing exposure dose from 66 mJ/cm2 to 24 mJ/cm2. On the other hand, there appeared tradeoff relationship between LCDU and dose for dense dot pattern, indicating photon-shot noise restriction, but strong dependency on patterning features. Design to improve acid generation efficiency was described based on acid generation mechanism in traditional chemically amplified materials which contains photo-acid generator (PAG) and polymer. Conventional EUV absorber comprises of organic compounds is expected to have 1.6 times higher EUV absorption than polyhydroxystyrene based on calculation. However, observed value of acid amount was comparable or significantly worse than polyhydroxystyrene.

Universal EUV in-band intensity detector

DOEpatents

Berger, Kurt W.

2004-08-24

Extreme ultraviolet light is detected using a universal in-band detector for detecting extreme ultraviolet radiation that includes: (a) an EUV sensitive photodiode having a diode active area that generates a current responsive to EUV radiation; (b) one or more mirrors that reflects EUV radiation having a defined wavelength(s) to the diode active area; and (c) a mask defining a pinhole that is positioned above the diode active area, wherein EUV radiation passing through the pinhole is restricted substantially to illuminating the diode active area.

Method for the manufacture of phase shifting masks for EUV lithography

DOEpatents

Stearns, Daniel G.; Sweeney, Donald W.; Mirkarimi, Paul B.; Barty, Anton

2006-04-04

A method for fabricating an EUV phase shift mask is provided that includes a substrate upon which is deposited a thin film multilayer coating that has a complex-valued reflectance. An absorber layer or a buffer layer is attached onto the thin film multilayer, and the thickness of the thin film multilayer coating is altered to introduce a direct modulation in the complex-valued reflectance to produce phase shifting features.

Extending CO2 cryogenic aerosol cleaning for advanced optical and EUV mask cleaning

NASA Astrophysics Data System (ADS)

Varghese, Ivin; Bowers, Charles W.; Balooch, Mehdi

2011-11-01

Cryogenic CO2 aerosol cleaning being a dry, chemically-inert and residue-free process is used in the production of optical lithography masks. It is an attractive cleaning option for the mask industry to achieve the requirement for removal of all printable soft defects and repair debris down to the 50nm printability specification. In the technique, CO2 clusters are formed by sudden expansion of liquid from high to almost atmospheric pressure through an optimally designed nozzle orifice. They are then directed on to the soft defects or debris for momentum transfer and subsequent damage free removal from the mask substrate. Unlike aggressive acid based wet cleaning, there is no degradation of the mask after processing with CO2, i.e., no critical dimension (CD) change, no transmission/phase losses, or chemical residue that leads to haze formation. Therefore no restriction on number of cleaning cycles is required to be imposed, unlike other cleaning methods. CO2 aerosol cleaning has been implemented for several years as full mask final clean in production environments at several state of the art mask shops. Over the last two years our group reported successful removal of all soft defects without damage to the fragile SRAF features, zero adders (from the cleaning and handling mechanisms) down to a 50nm printability specification. In addition, CO2 aerosol cleaning is being utilized to remove debris from Post-RAVE repair of hard defects in order to achieve the goal of no printable defects. It is expected that CO2 aerosol cleaning can be extended to extreme ultraviolet (EUV) masks. In this paper, we report advances being made in nozzle design qualification for optimum snow properties (size, velocity and flux) using Phase Doppler Anemometry (PDA) technique. In addition the two new areas of focus for CO2 aerosol cleaning i.e. pellicle glue residue removal on optical masks, and ruthenium (Ru) film on EUV masks are presented. Usually, the residue left over after the pellicle has been removed from returned masks (after long term usage/exposure in the wafer fab), requires a very aggressive SPM wet clean, that drastically reduces the available budget for mask properties (CD, phase/transmission). We show that CO2aerosol cleaning can be utilized to remove the bulk of the glue residue effectively, while preserving the mask properties. This application required a differently designed nozzle to impart the required removal force for the sticky glue residue. A new nozzle was developed and qualified that resulted in PRE in the range of 92-98%. Results also include data on a patterned mask that was exposed in a lithography stepper in a wafer production environment. On EUV mask, our group has experimentally demonstrated that 50 CO2 cleaning cycles of Ru film on the EUV Front-side resulted in no appreciable reflectivity change, implying that no degradation of the Ru film occurs.

Field results from a new die-to-database reticle inspection platform

NASA Astrophysics Data System (ADS)

Broadbent, William; Yokoyama, Ichiro; Yu, Paul; Seki, Kazunori; Nomura, Ryohei; Schmalfuss, Heiko; Heumann, Jan; Sier, Jean-Paul

2007-05-01

A new die-to-database high-resolution reticle defect inspection platform, TeraScanHR, has been developed for advanced production use with the 45nm logic node, and extendable for development use with the 32nm node (also the comparable memory nodes). These nodes will use predominantly ArF immersion lithography although EUV may also be used. According to recent surveys, the predominant reticle types for the 45nm node are 6% simple tri-tone and COG. Other advanced reticle types may also be used for these nodes including: dark field alternating, Mask Enhancer, complex tri-tone, high transmission, CPL, etc. Finally, aggressive model based OPC will typically be used which will include many small structures such as jogs, serifs, and SRAF (sub-resolution assist features) with accompanying very small gaps between adjacent structures. The current generation of inspection systems is inadequate to meet these requirements. The architecture and performance of the new TeraScanHR reticle inspection platform is described. This new platform is designed to inspect the aforementioned reticle types in die-to-database and die-to-die modes using both transmitted and reflected illumination. Recent results from field testing at two of the three beta sites are shown (Toppan Printing in Japan and the Advanced Mask Technology Center in Germany). The results include applicable programmed defect test reticles and advanced 45nm product reticles (also comparable memory reticles). The results show high sensitivity and low false detections being achieved. The platform can also be configured for the current 65nm, 90nm, and 130nm nodes.

When things go pear shaped: contour variations of contacts

NASA Astrophysics Data System (ADS)

Utzny, Clemens

2013-04-01

Traditional control of critical dimensions (CD) on photolithographic masks considers the CD average and a measure for the CD variation such as the CD range or the standard deviation. Also systematic CD deviations from the mean such as CD signatures are subject to the control. These measures are valid for mask quality verification as long as patterns across a mask exhibit only size variations and no shape variation. The issue of shape variations becomes especially important in the context of contact holes on EUV masks. For EUV masks the CD error budget is much smaller than for standard optical masks. This means that small deviations from the contact shape can impact EUV waver prints in the sense that contact shape deformations induce asymmetric bridging phenomena. In this paper we present a detailed study of contact shape variations based on regular product data. Two data sets are analyzed: 1) contacts of varying target size and 2) a regularly spaced field of contacts. Here, the methods of statistical shape analysis are used to analyze CD SEM generated contour data. We demonstrate that contacts on photolithographic masks do not only show size variations but exhibit also pronounced nontrivial shape variations. In our data sets we find pronounced shape variations which can be interpreted as asymmetrical shape squeezing and contact rounding. Thus we demonstrate the limitations of classic CD measures for describing the feature variations on masks. Furthermore we show how the methods of statistical shape analysis can be used for quantifying the contour variations thus paving the way to a new understanding of mask linearity and its specification.

Microfabrication of through holes in polydimethylsiloxane (PDMS) sheets using a laser plasma EUV source (Conference Presentation)

NASA Astrophysics Data System (ADS)

Makimura, Tetsuya; Urai, Hikari; Niino, Hiroyuki

2017-03-01

Polydimethylsiloxane (PDMS) is a material used for cell culture substrates / bio-chips and micro total analysis systems / lab-on-chips due to its flexibility, chemical / thermo-dynamic stability, bio-compatibility, transparency and moldability. For further development, it is inevitable to develop a technique to fabricate precise three dimensional structures on micrometer-scale at high aspect ratio. In the previous works, we reported a technique for high-quality micromachining of PDMS without chemical modification, by means of photo direct machining using laser plasma EUV sources. In the present work, we have investigated fabrication of through holes. The EUV radiations around 10 nm were generated by irradiation of Ta targets with Nd:YAG laser light (10 ns, 500 mJ/pulse). The generated EUV radiations were focused using an ellipsoidal mirror. It has a narrower incident angle than those in the previous works in order to form a EUV beam with higher directivity, so that higher aspect structures can be fabricated. The focused EUV beam was incident on PDMS sheets with a thickness of 15 micrometers, through holes in a contact mask placed on top of them. Using a contact mask with holes with a diameter of three micrometers, complete through holes with a diameter of two micrometers are fabricated in the PDMS sheet. Using a contact mask with two micrometer holes, however, ablation holes almost reaches to the back side of the PDMS sheet. The fabricated structures can be explained in terms of geometrical optics. Thus, we have developed a technique for micromachining of PDMS sheets at high aspect ratios.

Results from a new 193nm die-to-database reticle inspection platform

NASA Astrophysics Data System (ADS)

Broadbent, William H.; Alles, David S.; Giusti, Michael T.; Kvamme, Damon F.; Shi, Rui-fang; Sousa, Weston L.; Walsh, Robert; Xiong, Yalin

2010-05-01

A new 193nm wavelength high resolution reticle defect inspection platform has been developed for both die-to-database and die-to-die inspection modes. In its initial configuration, this innovative platform has been designed to meet the reticle qualification requirements of the IC industry for the 22nm logic and 3xhp memory generations (and shrinks) with planned extensions to the next generation. The 22nm/3xhp IC generation includes advanced 193nm optical lithography using conventional RET, advanced computational lithography, and double patterning. Further, EUV pilot line lithography is beginning. This advanced 193nm inspection platform has world-class performance and the capability to meet these diverse needs in optical and EUV lithography. The architecture of the new 193nm inspection platform is described. Die-to-database inspection results are shown on a variety of reticles from industry sources; these reticles include standard programmed defect test reticles, as well as advanced optical and EUV product and product-like reticles. Results show high sensitivity and low false and nuisance detections on complex optical reticle designs and small feature size EUV reticles. A direct comparison with the existing industry standard 257nm wavelength inspection system shows measurable sensitivity improvement for small feature sizes

High speed reflectometer for EUV mask-blanks

NASA Astrophysics Data System (ADS)

Wies, Christian; Lebert, Rainer; Jagle, Bernhard; Juschkin, L.; Sobel, F.; Seitz, H.; Walter, Ronny; Laubis, C.; Scholze, F.; Biel, W.; Steffens, O.

2005-06-01

AIXUV GmbH and partners have developed a high speed Reflectometer for EUV mask-blanks which is fully compliant with the SEMI-standard P38 for EUV-mask-blank metrology. The system has been installed in June 2004 at SCHOTT Lithotec AG. It features high throughput, high lateral and spectral resolution, high reproducibility and low absolute uncertainty. Using AIXUV's EUV-LAMP and debris mitigation, low cost-of-ownership and high availability is expected. The spectral reflectance of up to 3 mask-blanks per hour can be measured with at least 20 spots each. The system is push button-controlled. Results are stored in CSV file format. For a spot size of 0.1x1 mm2, 2000 spectral channels of 1.6 pm bandwidth are recorded from 11.6 nm to 14.8 nm. The reflectance measurement is based on the comparison of the sample under test to two reference mirrors calibrated at the PTB radiometry laboratory at BESSY II. The three reflection spectra are recorded simultaneously. For each spot more than 107 photons are accumulated in about 20 s, providing statistical reproducibility below 0.2% RMS. The total uncertainty is below 0.5% absolute. Wavelength calibration better than 1 pm RMS over the whole spectral range is achieved by reference to NIST published wavelengths of about 100 xenon emission lines. It is consistent with the wavelength of the krypton 3d-5p absorption resonance at 13.5947 nm to better than 2 pm.

High speed reflectometer for EUV mask-blanks

NASA Astrophysics Data System (ADS)

Wies, C.; Lebert, R.; Jaegle, B.; Juschkin, L.; Sobel, F.; Seitz, H.; Walter, R.; Laubis, C.; Scholze, F.; Biel, W.; Steffens, O.

2005-05-01

AIXUV GmbH and partners have developed a high speed Reflectometer for EUV mask-blanks which is fully compliant with the SEMI-standard P38 for EUV-mask-blank metrology. The system has been installed in June 2004 at SCHOTT Lithotec AG. It features high throughput, high lateral and spectral resolution, high reproduci-bility and low absolute uncertainty. Using AIXUV's EUV-LAMP and debris mitigation, low cost-of-ownership and high availability is expected. The spectral reflectance of up to 3 mask-blanks per hour can be measured with at least 20 spots each. The system is push button-controlled. Results are stored in CSV file format. For a spot size of 0.1×1 mm2, 2000 spectral chan-nels of 1.6 pm bandwidth are recorded from 11.6 nm to 14.8 nm. The reflectance measurement is based on the comparison of the sample under test to two reference mirrors calibrated at the PTB radiometry laboratory at BESSY II. The three reflection spectra are recorded simultaneously. For each spot more than 107 photons are ac-cumulated in about 20 s, providing statistical reproducibility below 0.2 % RMS. The total uncertainty is below 0.5 % absolute. Wavelength calibration better than 1 pm RMS over the whole spectral range is achieved by refe-rence to NIST published wavelengths of about 100 xenon emission lines. It is consistent with the wavelength of the krypton 3d-5p absorption resonance at 13.5947 nm to better than 2 pm.

Mask fabrication and its applications to extreme ultra-violet diffractive optics

NASA Astrophysics Data System (ADS)

Cheng, Yang-Chun

Short-wavelength radiation around 13nm of wavelength (Extreme Ultra-Violet, EUV) is being considered for patterning microcircuits, and other electronic chips with dimensions in the nanometer range. Interferometric Lithography (IL) uses two beams of radiation to form high-resolution interference fringes, as small as half the wavelength of the radiation used. As a preliminary step toward manufacturing technology, IL can be used to study the imaging properties of materials in a wide spectral range and at nanoscale dimensions. A simple implementation of IL uses two transmission diffraction gratings to form the interference pattern. More complex interference patterns can be created by using different types of transmission gratings. In this thesis, I describe the development of a EUV lithography system that uses diffractive optical elements (DOEs), from simple gratings to holographic structures. The exposure system is setup on a EUV undulator beamline at the Synchrotron Radiation Center, in the Center for NanoTechnology clean room. The setup of the EUV exposure system is relatively simple, while the design and fabrication of the DOE "mask" is complex, and relies on advanced nanofabrication techniques. The EUV interferometric lithography provides reliable EUV exposures of line/space patterns and is ideal for the development of EUV resist technology. In this thesis I explore the fabrication of these DOE for the EUV range, and discuss the processes I have developed for the fabrication of ultra-thin membranes. In addition, I discuss EUV holographic lithography and generalized Talbot imaging techniques to extend the capability of our EUV-IL system to pattern arbitrary shapes, using more coherent sources than the undulator. In a series of experiments, we have demonstrated the use of a soft X-ray (EUV) laser as effective source for EUV lithography. EUV-IL, as implemented at CNTech, is being used by several companies and research organizations to characterize photoresist materials.

Model based high NA anamorphic EUV RET

NASA Astrophysics Data System (ADS)

Jiang, Fan; Wiaux, Vincent; Fenger, Germain; Clifford, Chris; Liubich, Vlad; Hendrickx, Eric

2018-03-01

With the announcement of the extension of the Extreme Ultraviolet (EUV) roadmap to a high NA lithography tool that utilizes anamorphic optics design, an investigation of design tradeoffs unique to the imaging of anamorphic lithography tool is shown. An anamorphic optical proximity correction (OPC) solution has been developed that models fully the EUV near field electromagnetic effects and the anamorphic imaging using the Domain Decomposition Method (DDM). Clips of imec representative for the N3 logic node were used to demonstrate the OPC solutions on critical layers that will benefit from the increased contrast at high NA using anamorphic imaging. However, unlike isomorphic case, from wafer perspective, OPC needs to treat x and y differently. In the paper, we show a design trade-off seen unique to Anamorphic EUV, namely that using a mask rule of 48nm (mask scale), approaching current state of the art, limitations are observed in the available correction that can be applied to the mask. The metal pattern has a pitch of 24nm and CD of 12nm. During OPC, the correction of the metal lines oriented vertically are being limited by the mask rule of 12nm 1X. The horizontally oriented lines do not suffer from this mask rule limitation as the correction is allowed to go to 6nm 1X. For this example, the masks rules will need to be more aggressive to allow complete correction, or design rules and wafer processes (wafer rotation) would need to be created that utilize the orientation that can image more aggressive features. When considering VIA or block level correction, aggressive polygon corner to corner designs can be handled with various solutions, including applying a 45 degree chop. Multiple solutions are discussed with the metrics of edge placement error (EPE) and Process Variation Bands (PVBands), together with all the mask constrains. Noted in anamorphic OPC, the 45 degree chop is maintained at the mask level to meet mask manufacturing constraints, but results in skewed angle edge in wafer level correction. In this paper, we used both contact (Via/block) patterns and metal patterns for OPC practice. By comparing the EPE of horizontal and vertical patterns with a fixed mask rule check (MRC), and the PVBand, we focus on the challenges and the solutions of OPC with anamorphic High-NA lens.

Etch bias inversion during EUV mask ARC etch

NASA Astrophysics Data System (ADS)

Lajn, Alexander; Rolff, Haiko; Wistrom, Richard

2017-07-01

The introduction of EUV lithography to high volume manufacturing is now within reach for 7nm technology node and beyond (1), at least for some steps. The scheduling is in transition from long to mid-term. Thus, all contributors need to focus their efforts on the production requirements. For the photo mask industry, these requirements include the control of defectivity, CD performance and lifetime of their masks. The mask CD performance including CD uniformity, CD targeting, and CD linearity/ resolution, is predominantly determined by the photo resist performance and by the litho and etch processes. State-of-the-art chemically amplified resists exhibit an asymmetric resolution for directly and indirectly written features, which usually results in a similarly asymmetric resolution performance on the mask. This resolution gap may reach as high as multiple tens of nanometers on the mask level in dependence of the chosen processes. Depending on the printing requirements of the wafer process, a reduction or even an increase of this gap may be required. A potential way of tuning via the etch process, is to control the lateral CD contribution during etch. Aside from process tuning knobs like pressure, RF powers and gases, which usually also affect CD linearity and CD uniformity, the simplest knob is the etch time itself. An increased over etch time results in an increased CD contribution in the normal case. , We found that the etch CD contribution of ARC layer etch on EUV photo masks is reduced by longer over etch times. Moreover, this effect can be demonstrated to be present for different etch chambers and photo resists.

A new approach in dry technology for non-degrading optical and EUV mask cleaning

NASA Astrophysics Data System (ADS)

Varghese, Ivin; Smith, Ben; Balooch, Mehdi; Bowers, Chuck

2012-11-01

The Eco-Snow Systems group of RAVE N.P., Inc. has developed a new cleaning technique to target several of the advanced and next generation mask clean challenges. This new technique, especially when combined with Eco-Snow Systems cryogenic CO2 cleaning technology, provides several advantages over existing methods because it: 1) is solely based on dry technique without requiring additional complementary aggressive wet chemistries that degrade the mask, 2) operates at atmospheric pressure and therefore avoids expensive and complicated equipment associated with vacuum systems, 3) generates ultra-clean reactants eliminating possible byproduct adders, 4) can be applied locally for site specific cleaning without exposing the rest of the mask or can be used to clean the entire mask, 5) removes organic as well as inorganic particulates and film contaminations, and 6) complements current techniques utilized for cleaning of advanced masks such as reduced chemistry wet cleans. In this paper, we shall present examples demonstrating the capability of this new technique for removal of pellicle glue residues and for critical removal of carbon contamination on EUV masks.

Performance and stability of mask process correction for EBM-7000

NASA Astrophysics Data System (ADS)

Saito, Yasuko; Chen, George; Wang, Jen-Shiang; Bai, Shufeng; Howell, Rafael; Li, Jiangwei; Tao, Jun; VanDenBroeke, Doug; Wiley, Jim; Takigawa, Tadahiro; Ohnishi, Takayuki; Kamikubo, Takashi; Hara, Shigehiro; Anze, Hirohito; Hattori, Yoshiaki; Tamamushi, Shuichi

2010-05-01

In order to support complex optical masks today and EUV masks in the near future, it is critical to correct mask patterning errors with a magnitude of up to 20nm over a range of 2000nm at mask scale caused by short range mask process proximity effects. A new mask process correction technology, MPC+, has been developed to achieve the target requirements for the next generation node. In this paper, the accuracy and throughput performance of MPC+ technology is evaluated using the most advanced mask writing tool, the EBM-70001), and high quality mask metrology . The accuracy of MPC+ is achieved by using a new comprehensive mask model. The results of through-pitch and through-linewidth linearity curves and error statistics for multiple pattern layouts (including both 1D and 2D patterns) are demonstrated and show post-correction accuracy of 2.34nm 3σ for through-pitch/through-linewidth linearity. Implementing faster mask model simulation and more efficient correction recipes; full mask area (100cm2) processing run time is less than 7 hours for 32nm half-pitch technology node. From these results, it can be concluded that MPC+ with its higher precision and speed is a practical technology for the 32nm node and future technology generations, including EUV, when used with advance mask writing processes like the EBM-7000.

Dry etching technologies for reflective multilayer

NASA Astrophysics Data System (ADS)

Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Kase, Yoshihisa; Yoshimori, Tomoaki; Muto, Makoto; Nonaka, Mikio; Iwami, Munenori

2012-11-01

We have developed a highly integrated methodology for patterning Extreme Ultraviolet (EUV) mask, which has been highlighted for the lithography technique at the 14nm half-pitch generation and beyond. The EUV mask is characterized as a reflective-type mask which is completely different compared with conventional transparent-type of photo mask. And it requires not only patterning of absorber layer without damaging the underlying multi reflective layers (40 Si/Mo layers) but also etching multi reflective layers. In this case, the dry etch process has generally faced technical challenges such as the difficulties in CD control, etch damage to quartz substrate and low selectivity to the mask resist. Shibaura Mechatronics ARESTM mask etch system and its optimized etch process has already achieved the maximal etch performance at patterning two-layered absorber. And in this study, our process technologies of multi reflective layers will be evaluated by means of optimal combination of process gases and our optimized plasma produced by certain source power and bias power. When our ARES™ is used for multilayer etching, the user can choose to etch the absorber layer at the same time or etch only the multilayer.

Measurement of EUV lithography pupil amplitude and phase variation via image-based methodology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levinson, Zachary; Verduijn, Erik; Wood, Obert R.

2016-04-01

Here, an approach to image-based EUV aberration metrology using binary mask targets and iterative model-based solutions to extract both the amplitude and phase components of the aberrated pupil function is presented. The approach is enabled through previously developed modeling, fitting, and extraction algorithms. We seek to examine the behavior of pupil amplitude variation in real-optical systems. Optimized target images were captured under several conditions to fit the resulting pupil responses. Both the amplitude and phase components of the pupil function were extracted from a zone-plate-based EUV mask microscope. The pupil amplitude variation was expanded in three different bases: Zernike polynomials,more » Legendre polynomials, and Hermite polynomials. It was found that the Zernike polynomials describe pupil amplitude variation most effectively of the three.« less

Enabling laboratory EUV research with a compact exposure tool

NASA Astrophysics Data System (ADS)

Brose, Sascha; Danylyuk, Serhiy; Tempeler, Jenny; Kim, Hyun-su; Loosen, Peter; Juschkin, Larissa

2016-03-01

In this work we present the capabilities of the designed and realized extreme ultraviolet laboratory exposure tool (EUVLET) which has been developed at the RWTH-Aachen, Chair for the Technology of Optical Systems (TOS), in cooperation with the Fraunhofer Institute for Laser Technology (ILT) and Bruker ASC GmbH. Main purpose of this laboratory setup is the direct application in research facilities and companies with small batch production, where the fabrication of high resolution periodic arrays over large areas is required. The setup can also be utilized for resist characterization and evaluation of its pre- and post-exposure processing. The tool utilizes a partially coherent discharge produced plasma (DPP) source and minimizes the number of other critical components to a transmission grating, the photoresist coated wafer and the positioning system for wafer and grating and utilizes the Talbot lithography approach. To identify the limits of this approach first each component is analyzed and optimized separately and relations between these components are identified. The EUV source has been optimized to achieve the best values for spatial and temporal coherence. Phase-shifting and amplitude transmission gratings have been fabricated and exposed. Several commercially available electron beam resists and one EUV resist have been characterized by open frame exposures to determine their contrast under EUV radiation. Cold development procedure has been performed to further increase the resist contrast. By analyzing the exposure results it can be demonstrated that only a 1:1 copy of the mask structure can be fully resolved by the utilization of amplitude masks. The utilized phase-shift masks offer higher 1st order diffraction efficiency and allow a demagnification of the mask structure in the achromatic Talbot plane.

Evaluation results of a new EUV reticle pod based on SEMI E152

NASA Astrophysics Data System (ADS)

Ota, Kazuya; Yonekawa, Masami; Taguchi, Takao; Suga, Osamu

2010-04-01

To protect the reticle during shipping, storage and tool handling, various reticle pod concepts have been proposed and evaluated in the last 10 years. MIRAI-Selete has been developing EUV reticle handling technology and evaluating EUV reticle pods designed using "Dual Pod Concept" for four years. The concept was jointly proposed by Canon and Nikon at the EUV mask technology and standards workshop at Miyazaki in November 2004; a mask is doubly protected by an inner pod and an outer pod and the mask is carried into an exposure tool with the inner pod. Canon, Nikon and Entegris have started collaboration in 2005 and developed three types of EUV pod prototypes, alpha, beta and gamma. The gamma pods were evaluated by MIRAI-Selete and the superiority of the dual pod concept has been verified with many experimental data on shipping, storage and tool handling. The dual pod concept was standardized as SEMI E152-0709 "Mechanical Specification of EUV Pods for 150mm EUVL Reticles" in 2009. Canon, Nikon and Entegris have developed a new pod design compatible with SEMI E152; it has a Type A inner baseplate for uses with EUV exposure tools. The baseplate has two alignment windows, a window for a data matrix symbol and five pockets as the front edge grip exclusion volumes. In addition to the new features, there are some differences between the new SEMI compliant pod design and the former design "CNE-gamma", e.g. the material of the inner cover was changed to metal to reduce outgassing rate and the gap between the reticle and the side supports were widened to satisfy a requirement of the standard. MIRAI-Selete has evaluated the particle protective capability of the new SEMI compliant pods "cnPod" during shipping, storage and tool handling in vacuum and found the "cnPod" has the excellent particle protective capability and the dual pod concept can be used not only for EUVL pilot line but also for EUVL high volume manufacturing.

Phase measurements of EUV mask defects

DOE PAGES

Claus, Rene A.; Wang, Yow-Gwo; Wojdyla, Antoine; ...

2015-02-22

Extreme Ultraviolet (EUV) Lithography mask defects were examined on the actinic mask imaging system, SHARP, at Lawrence Berkeley National Laboratory. Also, a quantitative phase retrieval algorithm based on the Weak Object Transfer Function was applied to the measured through-focus aerial images to examine the amplitude and phase of the defects. The accuracy of the algorithm was demonstrated by comparing the results of measurements using a phase contrast zone plate and a standard zone plate. Using partially coherent illumination to measure frequencies that would otherwise fall outside the numerical aperture (NA), it was shown that some defects are smaller than themore » conventional resolution of the microscope. We found that the programmed defects of various sizes were measured and shown to have both an amplitude and a phase component that the algorithm is able to recover.« less

Compensation of flare-induced CD changes EUVL

DOEpatents

Bjorkholm, John E [Pleasanton, CA; Stearns, Daniel G [Los Altos, CA; Gullikson, Eric M [Oakland, CA; Tichenor, Daniel A [Castro Valley, CA; Hector, Scott D [Oakland, CA

2004-11-09

A method for compensating for flare-induced critical dimensions (CD) changes in photolithography. Changes in the flare level results in undesirable CD changes. The method when used in extreme ultraviolet (EUV) lithography essentially eliminates the unwanted CD changes. The method is based on the recognition that the intrinsic level of flare for an EUV camera (the flare level for an isolated sub-resolution opaque dot in a bright field mask) is essentially constant over the image field. The method involves calculating the flare and its variation over the area of a patterned mask that will be imaged and then using mask biasing to largely eliminate the CD variations that the flare and its variations would otherwise cause. This method would be difficult to apply to optical or DUV lithography since the intrinsic flare for those lithographies is not constant over the image field.

Plasma cleaning of nanoparticles from EUV mask materials by electrostatics

NASA Astrophysics Data System (ADS)

Lytle, W. M.; Raju, R.; Shin, H.; Das, C.; Neumann, M. J.; Ruzic, D. N.

2008-03-01

Particle contamination on surfaces used in extreme ultraviolet (EUV) mask blank deposition, mask fabrication, and patterned mask handling must be avoided since the contamination can create significant distortions and loss of reflectivity. Particles on the order of 10nm are problematic during MLM mirror fabrication, since the introduced defects disrupt the local Bragg planes. The most serious problem is the accumulation of particles on surfaces of patterned blanks during EUV light exposure, since > 25nm particles will be printed without an out-of-focus pellicle. Particle contaminants are also a problem with direct imprint processes since defects are printed every time. Plasma Assisted Cleaning by Electrostatics (PACE) works by utilizing a helicon plasma as well as a pulsed DC substrate bias to charge particle and repel them electrostatically from the surface. Removal of this nature is a dry cleaning method and removes contamination perpendicular from the surface instead of rolling or sweeping the particles off the surface, a benefit when cleaning patterned surfaces where contamination can be rolled or trapped between features. Also, an entire mask can be cleaned at once since the plasma can cover the entire surface, thus there is no need to focus in on an area to clean. Sophisticated particle contamination detection system utilizing high power laser called DEFCON is developed to analyze the particle removal after PACE cleaning process. PACE has shown greater than 90 % particle removal efficiencies for 30 to 220 nm PSL particles on ruthenium capped quartz. Removal results for silicon surfaces and quartz surfaces show similar removal efficiencies. Results of cleaning 80 nm PSL spheres from silicon substrates will be shown.

Design and pitch scaling for affordable node transition and EUV insertion scenario

NASA Astrophysics Data System (ADS)

Kim, Ryoung-han; Ryckaert, Julien; Raghavan, Praveen; Sherazi, Yasser; Debacker, Peter; Trivkovic, Darko; Gillijns, Werner; Tan, Ling Ee; Drissi, Youssef; Blanco, Victor; Bekaert, Joost; Mao, Ming; Larivière, Stephane; McIntyre, Greg

2017-04-01

imec's DTCO and EUV achievement toward imec 7nm (iN7) technology node which is industry 5nm node equivalent is reported with a focus on cost and scaling. Patterning-aware design methodology supports both iArF multiple patterning and EUV under one compliant design rule. FinFET device with contacted poly pitch of 42nm and metal pitch of 32nm with 7.5-track, 6.5-track, and 6-track standard cell library are explored. Scaling boosters are used to provide additional scaling and die cost benefit while lessening pitch shrink burden, and it makes EUV insertion more affordable. EUV pattern fidelity is optimized through OPC, SMO, M3D, mask sizing and SRAF. Processed wafers were characterized and edge-placement-error (EPE) variability is validated for EUV insertion. Scale-ability and cost of ownership of EUV patterning in aligned with iN7 standard cell design, integration and patterning specification are discussed.

Progress in coherent lithography using table-top extreme ultraviolet lasers

NASA Astrophysics Data System (ADS)

Li, Wei

Nanotechnology has drawn a wide variety of attention as interesting phenomena occurs when the dimension of the structures is in the nanometer scale. The particular characteristics of nanoscale structures had enabled new applications in different fields in science and technology. Our capability to fabricate these nanostructures routinely for sure will impact the advancement of nanoscience. Apart from the high volume manufacturing in semiconductor industry, a small-scale but reliable nanofabrication tool can dramatically help the research in the field of nanotechnology. This dissertation describes alternative extreme ultraviolet (EUV) lithography techniques which combine table-top EUV laser and various cost-effective imaging strategies. For each technique, numerical simulations, system design, experiment result and its analysis will be presented. In chapter II, a brief review of the main characteristics of table-top EUV lasers will be addressed concentrating on its high power and large coherence radius that enable the lithography application described herein. The development of a Talbot EUV lithography system which is capable of printing 50nm half pitch nanopatterns will be illustrated in chapter III. A detailed discussion of its resolution limit will be presented followed by the development of X-Y-Z positioning stage, the fabrication protocol for diffractive EUV mask, and the pattern transfer using self- developed ion beam etching, and the dose control unit. In addition, this dissertation demonstrated the capability to fabricate functional periodic nanostructures using Talbot EUV lithography. After that, resolution enhancement techniques like multiple exposure, displacement Talbot EUV lithography, fractional Talbot EUV lithography, and Talbot lithography using 18.9nm amplified spontaneous emission laser will be demonstrated. Chapter IV will describe a hybrid EUV lithography which combines the Talbot imaging and interference lithography rendering a high resolution interference pattern whose lattice is modified by a custom designed Talbot mask. In other words, this method enables filling the arbitrary Talbot cell with ultra-fine interference nanofeatures. Detailed optics modeling, system design and experiment results using He-Ne laser and table top EUV laser are included. The last part of chapter IV will analyze its exclusive advantages over traditional Talbot or interference lithography.

Demonstration of an N7 integrated fab process for metal oxide EUV photoresist

NASA Astrophysics Data System (ADS)

De Simone, Danilo; Mao, Ming; Kocsis, Michael; De Schepper, Peter; Lazzarino, Frederic; Vandenberghe, Geert; Stowers, Jason; Meyers, Stephen; Clark, Benjamin L.; Grenville, Andrew; Luong, Vinh; Yamashita, Fumiko; Parnell, Doni

2016-03-01

Inpria has developed a directly patternable metal oxide hard-mask as a robust, high-resolution photoresist for EUV lithography. In this paper we demonstrate the full integration of a baseline Inpria resist into an imec N7 BEOL block mask process module. We examine in detail both the lithography and etch patterning results. By leveraging the high differential etch resistance of metal oxide photoresists, we explore opportunities for process simplification and cost reduction. We review the imaging results from the imec N7 block mask patterns and its process windows as well as routes to maximize the process latitude, underlayer integration, etch transfer, cross sections, etch equipment integration from cross metal contamination standpoint and selective resist strip process. Finally, initial results from a higher sensitivity Inpria resist are also reported. A dose to size of 19 mJ/cm2 was achieved to print pillars as small as 21nm.

Shot noise, LER, and quantum efficiency of EUV photoresists

NASA Astrophysics Data System (ADS)

Brainard, Robert L.; Trefonas, Peter; Lammers, Jeroen H.; Cutler, Charlotte A.; Mackevich, Joseph F.; Trefonas, Alexander; Robertson, Stewart A.

2004-05-01

The shot noise, line edge roughness (LER) and quantum efficiency of EUV interaction with seven resists related to EUV-2D (SP98248B) are studied. These resists were identical to EUV-2D except were prepared with seven levels of added base while keeping all other resist variables constant. These seven resists were patterned with EUV lithography, and LER was measured on 100-200 nm dense lines. Similarly, the resists were also imaged using DUV lithography and LER was determined for 300-500 nm dense lines. LER results for both wavelengths were plotted against Esize. Both curves show very similar LER behavior-the resists requiring low doses have poor LER, whereas the resists requiring high doses have good LER. One possible explanation for the observed LER response is that the added base improves LER by reacting with the photogenerated acid to control the lateral spread of acid, leading to better chemical contrast at the line edge. An alternative explanation to the observed relationship between LER and Esize is that shot-noise generated LER decreases as the number of photons absorbed at the line edge increases. We present an analytical model for the influence of shot noise based on Poisson statistics that preidicts that the LER is proportional to (Esize)-1/2. Indeed, both sets of data give straight lines when plotted this way (DUV r2 = 0.94; EUV r2 = 0.97). We decided to further evaluate this interpretation by constructing a simulation model for shot noise resulting from exposure and acid diffusion at the mask edge. In order to acquire the data for this model, we used the base titration method developed by Szmanda et al. to determine C-parameters and hence the quantum efficiency for producing photogenerated acid. This information, together with film absorptivity, allows the calculation of number and location of acid molecules generated at the mask edgte by assuming a stochastic distribution of individual photons corresponding to the aerial image function. The edge "roughness" of the acid molecule distribution in the film at the mask edge is then simulated as a function of acid diffusion length and compared to the experimental data. In addition, comparisoins between of the number of acid molecules generated and photons consumed leads to values of quantum efficiencies for these EUV resists.

Latest developments on EUV reticle and pellicle research and technology at TNO

NASA Astrophysics Data System (ADS)

Verberk, Rogier; Koster, Norbert; te Sligte, Edwin; Staring, Wilbert

2017-06-01

At TNO an extensive EUV optics life time program has been running for over 15 years together with our partners ASML and Carl Zeiss. This has contributed to the upcoming introduction of EUV High Volume Manufacturing (HVM). To further help the industry with the introduction of EUV, TNO has worked on extending their facilities with a number of reticle and pellicle research infrastructure facilities. In this paper we will show some of the facilities that are available at TNO and shortly introduce their capabilities. Recently we have opened our EBL2 facility, which is an EUV Beam Line (EBL2) meant for studying the effects of high power EUV illumination on optics, reticles and pellicles up to the power roadmap of 500 W at intermediate Focus (IF). This facility is open to users from all over the world and is beneficial for the industry in helping developing alternative capping layers and contamination control strategies for optics lifetime, new absorber materials, pellicles and resists. The EBL2 system has seen first light in December 2016 and is now in the final stage of acceptance testing and qualification. It is expected that the system will be fully operational in the third quarter of 2017, and available for users. It is possible to transfer reticles to and from the EBL2 by means of the reticle handler using the dual pod interface. This secures backside cleanliness to NXE standards and thus enables wafer printing on a NXE tool in a later stage after the exposures and inspection at EBL2. Besides EBL2, a high performance and ultra-clean reticle handler is available at TNO. This handler incorporates our particle scanner Rapid Nano 4 for front side inspection of reticle blanks with a detection limit down to 20 nm particles. Attached to the handler is also an Optical Coherence Tomography (OCT) inspection tool for back-side reticle or pellicle inspection with a resolution down to 1 micron.

Optimizing defect inspection strategy through the use of design-aware database control layers

NASA Astrophysics Data System (ADS)

Stoler, Dvori; Ruch, Wayne; Ma, Weimin; Chakravarty, Swapnajit; Liu, Steven; Morgan, Ray; Valadez, John; Moore, Bill; Burns, John

2007-10-01

Resolution limitations in the mask making process can cause differences between the features that appear in a database and those printed to a reticle. These differences may result from intentional or unintentional features in the database exceeding the resolution limit of the mask making process such as small gaps or lines in the data, line end shortening on small sub-resolution assist features etc creating challenges to both mask writing and mask inspection. Areas with high variance from design to mask, often referred to as high MEEF areas (mask error enhancement factor), become highly problematic and can directly impact mask and device yield, mask manufacturing cycle time and ultimately mask costs. Specific to mask inspection it may be desirable to inspect certain non-critical or non-relevant features at reduced sensitivity so as not to detect real, but less significant process defects. In contrast there may also be times where increased sensitivity is required for critical mask features or areas. Until recently, this process was extremely manual, creating added time and cost to the mask inspection cycle. Shifting to more intelligent and automated inspection flows is the key focus of this paper. A novel approach to importing design data directly into the mask inspection to include both MDP generated MRC errors files and LRC generated MEEF files. The results of recently developed inspection and review capability based upon controlling defect inspection using design aware data base control layers on a pixel basis are discussed. Typical mask shop applications and implementations will be shown.

Monte Carlo sensitivity analysis of EUV mask reflectivity and its impact on OPC accuracy

NASA Astrophysics Data System (ADS)

Chen, Yulu; Wood, Obert; Rankin, Jed; Gullikson, Eric; Meyer-Ilse, Julia; Sun, Lei; Qi, Zhengqing John; Goodwin, Francis; Kye, Jongwook

2017-03-01

Unlike optical masks which are transmissive optical elements, use of extreme ultraviolet (EUV) radiation requires a reflective mask structure - a multi-layer coating consisting of alternating layers of high-Z (wave impedance) and low-Z materials that provide enhanced reflectivity over a narrow wavelength band peaked at the Bragg wavelength.1 Absorber side wall angle, corner rounding,2 surface roughness,3 and defects4 affect mask performance, but even seemingly simple parameters like bulk reflectivity on mirror and absorber surfaces can have a profound influence on imaging. For instance, using inaccurate reflectivity values at small and large incident angles would diminish the benefits of source mask co-optimization (SMO) and result in larger than expected pattern shifts. The goal of our work is to calculate the variation in mask reflectivity due to various sources of inaccuracies using Monte Carlo simulations. Such calculation is necessary as small changes in the thickness and optical properties of the high-Z and low-Z materials can cause substantial variations in reflectivity. This is further complicated by undesirable intermixing between the two materials used to create the reflector.5 One of the key contributors to mask reflectivity fluctuation is identified to be the intermixing layer thickness. We also investigate the impacts on OPC when the wrong mask information is provided, and evaluate the deterioration of overlapping process window. For a hypothetical N7 via layer, the lack of accurate mask information costs 25% of the depth of focus at 5% exposure latitude. Our work would allow the determination of major contributors to mask reflectivity variation, drive experimental efforts of measuring such contributors, provide strategies to optimize mask reflectivity, and quantize the OPC errors due to imperfect mask modeling.

Aerial image based die-to-model inspections of advanced technology masks

NASA Astrophysics Data System (ADS)

Kim, Jun; Lei, Wei-Guo; McCall, Joan; Zaatri, Suheil; Penn, Michael; Nagpal, Rajesh; Faivishevsky, Lev; Ben-Yishai, Michael; Danino, Udy; Tam, Aviram; Dassa, Oded; Balasubramanian, Vivek; Shah, Tejas H.; Wagner, Mark; Mangan, Shmoolik

2009-10-01

Die-to-Model (D2M) inspection is an innovative approach to running inspection based on a mask design layout data. The D2M concept takes inspection from the traditional domain of mask pattern to the preferred domain of the wafer aerial image. To achieve this, D2M transforms the mask layout database into a resist plane aerial image, which in turn is compared to the aerial image of the mask, captured by the inspection optics. D2M detection algorithms work similarly to an Aerial D2D (die-to-die) inspection, but instead of comparing a die to another die it is compared to the aerial image model. D2M is used whenever D2D inspection is not practical (e.g., single die) or when a validation of mask conformity to design is needed, i.e., for printed pattern fidelity. D2M is of particular importance for inspection of logic single die masks, where no simplifying assumption of pattern periodicity may be done. The application can tailor the sensitivity to meet the needs at different locations, such as device area, scribe lines and periphery. In this paper we present first test results of the D2M mask inspection application at a mask shop. We describe the methodology of using D2M, and review the practical aspects of the D2M mask inspection.

Using synchrotron light to accelerate EUV resist and mask materials learning

NASA Astrophysics Data System (ADS)

Naulleau, Patrick; Anderson, Christopher N.; Baclea-an, Lorie-Mae; Denham, Paul; George, Simi; Goldberg, Kenneth A.; Jones, Gideon; McClinton, Brittany; Miyakawa, Ryan; Mochi, Iacopo; Montgomery, Warren; Rekawa, Seno; Wallow, Tom

2011-03-01

As commercialization of extreme ultraviolet lithography (EUVL) progresses, direct industry activities are being focused on near term concerns. The question of long term extendibility of EUVL, however, remains crucial given the magnitude of the investments yet required to make EUVL a reality. Extendibility questions are best addressed using advanced research tools such as the SEMATECH Berkeley microfield exposure tool (MET) and actinic inspection tool (AIT). Utilizing Lawrence Berkeley National Laboratory's Advanced Light Source facility as the light source, these tools benefit from the unique properties of synchrotron light enabling research at nodes generations ahead of what is possible with commercial tools. The MET for example uses extremely bright undulator radiation to enable a lossless fully programmable coherence illuminator. Using such a system, resolution enhancing illuminations achieving k1 factors of 0.25 can readily be attained. Given the MET numerical aperture of 0.3, this translates to an ultimate resolution capability of 12 nm. Using such methods, the SEMATECH Berkeley MET has demonstrated resolution in resist to 16-nm half pitch and below in an imageable spin-on hard mask. At a half pitch of 16 nm, this material achieves a line-edge roughness of 2 nm with a correlation length of 6 nm. These new results demonstrate that the observed stall in ultimate resolution progress in chemically amplified resists is a materials issue rather than a tool limitation. With a resolution limit of 20-22 nm, the CAR champion from 2008 remains as the highest performing CAR tested to date. To enable continued advanced learning in EUV resists, SEMATECH has initiated a plan to implement a 0.5 NA microfield tool at the Advanced Light Source synchrotron facility. This tool will be capable of printing down to 8-nm half pitch.

MTO-like reference mask modeling for advanced inverse lithography technology patterns

NASA Astrophysics Data System (ADS)

Park, Jongju; Moon, Jongin; Son, Suein; Chung, Donghoon; Kim, Byung-Gook; Jeon, Chan-Uk; LoPresti, Patrick; Xue, Shan; Wang, Sonny; Broadbent, Bill; Kim, Soonho; Hur, Jiuk; Choo, Min

2017-07-01

Advanced Inverse Lithography Technology (ILT) can result in mask post-OPC databases with very small address units, all-angle figures, and very high vertex counts. This creates mask inspection issues for existing mask inspection database rendering. These issues include: large data volumes, low transfer rate, long data preparation times, slow inspection throughput, and marginal rendering accuracy leading to high false detections. This paper demonstrates the application of a new rendering method including a new OASIS-like mask inspection format, new high-speed rendering algorithms, and related hardware to meet the inspection challenges posed by Advanced ILT masks.

Method for extreme ultraviolet lithography

DOEpatents

Felter, T. E.; Kubiak, Glenn D.

1999-01-01

A method of producing a patterned array of features, in particular, gate apertures, in the size range 0.4-0.05 .mu.m using projection lithography and extreme ultraviolet (EUV) radiation. A high energy laser beam is used to vaporize a target material in order to produce a plasma which in turn, produces extreme ultraviolet radiation of a characteristic wavelength of about 13 nm for lithographic applications. The radiation is transmitted by a series of reflective mirrors to a mask which bears the pattern to be printed. The demagnified focused mask pattern is, in turn, transmitted by means of appropriate optics and in a single exposure, to a substrate coated with photoresists designed to be transparent to EUV radiation and also satisfy conventional processing methods.

Method for extreme ultraviolet lithography

DOEpatents

Felter, T. E.; Kubiak, G. D.

2000-01-01

A method of producing a patterned array of features, in particular, gate apertures, in the size range 0.4-0.05 .mu.m using projection lithography and extreme ultraviolet (EUV) radiation. A high energy laser beam is used to vaporize a target material in order to produce a plasma which in turn, produces extreme ultraviolet radiation of a characteristic wavelength of about 13 nm for lithographic applications. The radiation is transmitted by a series of reflective mirrors to a mask which bears the pattern to be printed. The demagnified focused mask pattern is, in turn, transmitted by means of appropriate optics and in a single exposure, to a substrate coated with photoresists designed to be transparent to EUV radiation and also satisfy conventional processing methods.

Modeling high-efficiency extreme ultraviolet etched multilayer phase-shift masks

NASA Astrophysics Data System (ADS)

Sherwin, Stuart; Neureuther, Andrew; Naulleau, Patrick

2017-10-01

Achieving high-throughput extreme ultraviolet (EUV) patterning remains a major challenge due to low source power; phase-shift masks can help solve this challenge for dense features near the resolution limit by creating brighter images than traditional absorber masks when illuminated with the same source power. We explore applications of etched multilayer phase-shift masks for EUV lithography, both in the current-generation 0.33 NA and next-generation 0.55 NA systems. We derive analytic formulas for the thin-mask throughput gains, which are 2.42× for lines and spaces and 5.86× for contacts compared with an absorber mask with dipole and quadrupole illumination, respectively. Using rigorous finite-difference time-domain simulations, we quantify variations in these gains by pitch and orientation, finding 87% to 113% of the thin-mask value for lines and spaces and a 91% to 99% for contacts. We introduce an edge placement error metric, which accounts for CD errors, relative feature motion, and telecentricity errors, and use this metric both to optimize mask designs for individual features and to explore which features can be printed on the same mask. Furthermore, we find that although partial coherence shrinks the process window, at an achievable sigma of 0.2 we obtain a depth of focus of 340 nm and an exposure latitude of 39.2%, suggesting that partial coherence will not limit the feasibility of this technology. Finally, we show that many problems such as sensitivity to etch uniformity can be greatly mitigated using a central obscuration in the imaging pupil.

Flat-field anastigmatic mirror objective for high-magnification extreme ultraviolet microscopy

NASA Astrophysics Data System (ADS)

Toyoda, Mitsunori

2015-08-01

To apply high-definition microscopy to the extreme ultraviolet (EUV) region in practice, i.e. to enable in situ observation of living tissue and the at-wavelength inspection of lithography masks, we constructed a novel reflective objective made of three multilayer mirrors. This objective is configured as a two-stage imaging system made of a Schwarzschild two-mirror system as the primary objective and an additional magnifier with a single curved mirror. This two-stage configuration can provide a high magnification of 1500, which is suitable for real-time observation with an EUV charge coupled device (CCD) camera. Besides, since off-axis aberrations can be corrected by the magnifier, which provides field flattener optics, we are able to configure the objective as a flat-field anastigmatic system, in which we will have a diffraction-limited spatial resolution over a large field-of-view. This paper describes in detail the optical design of the present objective. After calculating the closed-form equations representing the third-order aberrations of the objective, we apply these equations to practical design examples with a numerical aperture of 0.25 and an operation wavelength of 13.5 nm. We also confirm the imaging performances of this novel design by using the numerical ray-tracing method.

Wafer plane inspection for advanced reticle defects

NASA Astrophysics Data System (ADS)

Nagpal, Rajesh; Ghadiali, Firoz; Kim, Jun; Huang, Tracy; Pang, Song

2008-05-01

Readiness of new mask defect inspection technology is one of the key enablers for insertion & transition of the next generation technology from development into production. High volume production in mask shops and wafer fabs demands a reticle inspection system with superior sensitivity complemented by a low false defect rate to ensure fast turnaround of reticle repair and defect disposition (W. Chou et al 2007). Wafer Plane Inspection (WPI) is a novel approach to mask defect inspection, complementing the high resolution inspection capabilities of the TeraScanHR defect inspection system. WPI is accomplished by using the high resolution mask images to construct a physical mask model (D. Pettibone et al 1999). This mask model is then used to create the mask image in the wafer aerial plane. A threshold model is applied to enhance the inspectability of printing defects. WPI can eliminate the mask restrictions imposed on OPC solutions by inspection tool limitations in the past. Historically, minimum image restrictions were required to avoid nuisance inspection stops and/or subsequent loss of sensitivity to defects. WPI has the potential to eliminate these limitations by moving the mask defect inspections to the wafer plane. This paper outlines Wafer Plane Inspection technology, and explores the application of this technology to advanced reticle inspection. A total of twelve representative critical layers were inspected using WPI die-to-die mode. The results from scanning these advanced reticles have shown that applying WPI with a pixel size of 90nm (WPI P90) captures all the defects of interest (DOI) with low false defect detection rates. In validating CD predictions, the delta CDs from WPI are compared against Aerial Imaging Measurement System (AIMS), where a good correlation is established between WPI and AIMSTM.

Evaluating practical vs. theoretical inspection system capability with a new programmed defect test mask designed for 3X and 4X technology nodes

NASA Astrophysics Data System (ADS)

Glasser, Joshua; Pratt, Tim

2008-10-01

Programmed defect test masks serve the useful purpose of evaluating inspection system sensitivity and capability. It is widely recognized that when evaluating inspection system capability, it is important to understand the actual sensitivity of the inspection system in production; yet unfortunately we have observed that many test masks are a more accurate judge of theoretical sensitivity rather than real-world usable capability. Use of ineffective test masks leave the purchaser of inspection equipment open to the risks of over-estimating the capability of their inspection solution and overspecifying defect sensitivity to their customers. This can result in catastrophic yield loss for device makers. In this paper we examine some of the lithography-related technology advances which place an increasing burden on mask inspection complexity, such as MEEF, defect printability estimation, aggressive OPC, double patterning, and OPC jogs. We evaluate the key inspection system component contributors to successful mask inspection, including what can "go wrong" with these components. We designed and fabricated a test mask which both (a) more faithfully represents actual production use cases; and (b) stresses the key components of the inspection system. This mask's patterns represent 32nm, 36nm, and 45nm logic and memory technology including metal and poly like background patterns with programmed defects. This test mask takes into consideration requirements of advanced lithography, such as MEEF, defect printability, assist features, nearly-repetitive patterns, and data preparation. This mask uses patterns representative of 32nm, 36nm, and 45nm logic, flash, and DRAM technology. It is specifically designed to have metal and poly like background patterns with programmed defects. The mask is complex tritone and was designed for annular immersion lithography.

An open-architecture approach to defect analysis software for mask inspection systems

NASA Astrophysics Data System (ADS)

Pereira, Mark; Pai, Ravi R.; Reddy, Murali Mohan; Krishna, Ravi M.

2009-04-01

Industry data suggests that Mask Inspection represents the second biggest component of Mask Cost and Mask Turn Around Time (TAT). Ever decreasing defect size targets lead to more sensitive mask inspection across the chip, thus generating too many defects. Hence, more operator time is being spent in analyzing and disposition of defects. Also, the fact that multiple Mask Inspection Systems and Defect Analysis strategies would typically be in use in a Mask Shop or a Wafer Foundry further complicates the situation. In this scenario, there is a need for a versatile, user friendly and extensible Defect Analysis software that reduces operator analysis time and enables correct classification and disposition of mask defects by providing intuitive visual and analysis aids. We propose a new vendor-neutral defect analysis software, NxDAT, based on an open architecture. The open architecture of NxDAT makes it easily extensible to support defect analysis for mask inspection systems from different vendors. The capability to load results from mask inspection systems from different vendors either directly or through a common interface enables the functionality of establishing correlation between inspections carried out by mask inspection systems from different vendors. This capability of NxDAT enhances the effectiveness of defect analysis as it directly addresses the real-life scenario where multiple types of mask inspection systems from different vendors co-exist in mask shops or wafer foundries. The open architecture also potentially enables loading wafer inspection results as well as loading data from other related tools such as Review Tools, Repair Tools, CD-SEM tools etc, and correlating them with the corresponding mask inspection results. A unique concept of Plug-In interface to NxDAT further enhances the openness of the architecture of NxDAT by enabling end-users to add their own proprietary defect analysis and image processing algorithms. The plug-in interface makes it possible for the end-users to make use of their collected knowledge through the years of experience in mask inspection process by encapsulating the knowledge into software utilities and plugging them into NxDAT. The plug-in interface is designed with the intent of enabling the pro-active mask defect analysis teams to build competitive differentiation into their defect analysis process while protecting their knowledge internally within their company. By providing interface with all major standard layout and mask data formats, NxDAT enables correlation of defect data on reticles with design and mask databases, further extending the effectiveness of defect analysis for D2DB inspection. NxDAT also includes many other advanced features for easy and fast navigation, visual display of defects, defect selection, multi-tier classification, defect clustering and gridding, sophisticated CD and contact measurement analysis, repeatability analysis such as adder analysis, defect trend, capture rate etc.

Nearly amorphous Mo-N gratings for ultimate resolution in extreme ultraviolet interference lithography

NASA Astrophysics Data System (ADS)

Wang, L.; Kirk, E.; Wäckerlin, C.; Schneider, C. W.; Hojeij, M.; Gobrecht, J.; Ekinci, Y.

2014-06-01

We present fabrication and characterization of high-resolution and nearly amorphous Mo1 - xNx transmission gratings and their use as masks for extreme ultraviolet (EUV) interference lithography. During sputter deposition of Mo, nitrogen is incorporated into the film by addition of N2 to the Ar sputter gas, leading to suppression of Mo grain growth and resulting in smooth and homogeneous thin films with a negligible grain size. The obtained Mo0.8N0.2 thin films, as determined by x-ray photoelectron spectroscopy, are characterized to be nearly amorphous using x-ray diffraction. We demonstrate a greatly reduced Mo0.8N0.2 grating line edge roughness compared with pure Mo grating structures after e-beam lithography and plasma dry etching. The amorphous Mo0.8N0.2 thin films retain, to a large extent, the benefits of Mo as a phase grating material for EUV wavelengths, providing great advantages for fabrication of highly efficient diffraction gratings with extremely low roughness. Using these grating masks, well-resolved dense lines down to 8 nm half-pitch are fabricated with EUV interference lithography.

EUV multilayer defect compensation (MDC) by absorber pattern modification: from theory to wafer validation

NASA Astrophysics Data System (ADS)

Pang, Linyong; Hu, Peter; Satake, Masaki; Tolani, Vikram; Peng, Danping; Li, Ying; Chen, Dongxue

2011-11-01

According to the ITRS roadmap, mask defects are among the top technical challenges to introduce extreme ultraviolet (EUV) lithography into production. Making a multilayer defect-free extreme ultraviolet (EUV) blank is not possible today, and is unlikely to happen in the next few years. This means that EUV must work with multilayer defects present on the mask. The method proposed by Luminescent is to compensate effects of multilayer defects on images by modifying the absorber patterns. The effect of a multilayer defect is to distort the images of adjacent absorber patterns. Although the defect cannot be repaired, the images may be restored to their desired targets by changing the absorber patterns. This method was first introduced in our paper at BACUS 2010, which described a simple pixel-based compensation algorithm using a fast multilayer model. The fast model made it possible to complete the compensation calculations in seconds, instead of days or weeks required for rigorous Finite Domain Time Difference (FDTD) simulations. Our SPIE 2011 paper introduced an advanced compensation algorithm using the Level Set Method for 2D absorber patterns. In this paper the method is extended to consider process window, and allow repair tool constraints, such as permitting etching but not deposition. The multilayer defect growth model is also enhanced so that the multilayer defect can be "inverted", or recovered from the top layer profile using a calibrated model.

The verification of printability about marginal defects and the detectability at the inspection tool in sub 50nm node

NASA Astrophysics Data System (ADS)

Lee, Hyemi; Jeong, Goomin; Seo, Kangjun; Kim, Sangchul; kim, changreol

2008-05-01

Since mask design rule is smaller and smaller, Defects become one of the issues dropping the mask yield. Furthermore controlled defect size become smaller while masks are manufactured. According to ITRS roadmap on 2007, controlled defect size is 46nm in 57nm node and 36nm in 45nm node on a mask. However the machine development is delayed in contrast with the speed of the photolithography development. Generally mask manufacturing process is divided into 3 parts. First part is patterning on a mask and second part is inspecting the pattern and repairing the defect on the mask. At that time, inspection tools of transmitted light type are normally used and are the most trustful as progressive type in the developed inspection tools until now. Final part is shipping the mask after the qualifying the issue points and weak points. Issue points on a mask are qualified by using the AIMS (Aerial image measurement system). But this system is including the inherent error possibility, which is AIMS measures the issue points based on the inspection results. It means defects printed on a wafer are over the specific size detected by inspection tools and the inspection tool detects the almost defects. Even though there are no tools to detect the 46nm and 36nm defects suggested by ITRS roadmap, this assumption is applied to manufacturing the 57nm and 45nm device. So we make the programmed defect mask consisted with various defect type such as spot, clear extension, dark extension and CD variation on L/S(line and space), C/H(contact hole) and Active pattern in 55nm and 45nm node. And the programmed defect mask was inspected by using the inspection tool of transmitted light type and was measured by using AIMS 45-193i. Then the marginal defects were compared between the inspection tool and AIMS. Accordingly we could verify whether defect size is proper or not, which was suggested to be controlled on a mask by ITRS roadmap. Also this result could suggest appropriate inspection tools for next generation device among the inspection tools of transmitted light type, reflected light type and aerial image type.

Photoresist composition for extreme ultraviolet lithography

DOEpatents

Felter, T. E.; Kubiak, G. D.

1999-01-01

A method of producing a patterned array of features, in particular, gate apertures, in the size range 0.4-0.05 .mu.m using projection lithography and extreme ultraviolet (EUV) radiation. A high energy laser beam is used to vaporize a target material in order to produce a plasma which in turn, produces extreme ultraviolet radiation of a characteristic wavelength of about 13 nm for lithographic applications. The radiation is transmitted by a series of reflective mirrors to a mask which bears the pattern to be printed. The demagnified focused mask pattern is, in turn, transmitted by means of appropriate optics and in a single exposure, to a substrate coated with photoresists designed to be transparent to EUV radiation and also satisfy conventional processing methods. A photoresist composition for extreme ultraviolet radiation of boron carbide polymers, hydrochlorocarbons and mixtures thereof.

The lithographer's dilemma: shrinking without breaking the bank

NASA Astrophysics Data System (ADS)

Levinson, Harry J.

2013-10-01

It can no longer be assumed that the lithographic scaling which has previously driven Moore's Law will lead in the future to reduced cost per transistor. Until recently, higher prices for lithography tools were offset by improvements in scanner productivity. The necessity of using double patterning to extend scaling beyond the single exposure resolution limit of optical lithography has resulted in a sharp increase in the cost of patterning a critical construction layer that has not been offset by improvements in exposure tool productivity. Double patterning has also substantially increased the cost of mask sets. EUV lithography represents a single patterning option, but the combination of very high exposure tools prices, moderate throughput, high maintenance costs, and expensive mask blanks makes this a solution more expensive than optical double patterning but less expensive than triple patterning. Directed self-assembly (DSA) could potentially improve wafer costs, but this technology currently is immature. There are also design layout and process integration issues associated with DSA that need to be solved in order to obtain full benefit from tighter pitches. There are many approaches for improving the cost effectiveness of lithography. Innovative double patterning schemes lead to smaller die. EUV lithography productivity can be improved with higher power light sources and improved reliability. There are many technical and business challenges for extending EUV lithography to higher numerical apertures. Efficient contact hole and cut mask solutions are needed, as well as very tight overlay control, regardless of lithographic solution.

Extension of optical lithography by mask-litho integration with computational lithography

NASA Astrophysics Data System (ADS)

Takigawa, T.; Gronlund, K.; Wiley, J.

2010-05-01

Wafer lithography process windows can be enlarged by using source mask co-optimization (SMO). Recently, SMO including freeform wafer scanner illumination sources has been developed. Freeform sources are generated by a programmable illumination system using a micro-mirror array or by custom Diffractive Optical Elements (DOE). The combination of freeform sources and complex masks generated by SMO show increased wafer lithography process window and reduced MEEF. Full-chip mask optimization using source optimized by SMO can generate complex masks with small variable feature size sub-resolution assist features (SRAF). These complex masks create challenges for accurate mask pattern writing and low false-defect inspection. The accuracy of the small variable-sized mask SRAF patterns is degraded by short range mask process proximity effects. To address the accuracy needed for these complex masks, we developed a highly accurate mask process correction (MPC) capability. It is also difficult to achieve low false-defect inspections of complex masks with conventional mask defect inspection systems. A printability check system, Mask Lithography Manufacturability Check (M-LMC), is developed and integrated with 199-nm high NA inspection system, NPI. M-LMC successfully identifies printable defects from all of the masses of raw defect images collected during the inspection of a complex mask. Long range mask CD uniformity errors are compensated by scanner dose control. A mask CD uniformity error map obtained by mask metrology system is used as input data to the scanner. Using this method, wafer CD uniformity is improved. As reviewed above, mask-litho integration technology with computational lithography is becoming increasingly important.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naulleau, Patrick

With demonstrated resist resolution of 20 nm half pitch, the SEMATECH Berkeley BUV microfield exposure tool continues to push crucial advances in the areas of BUY resists and masks. The ever progressing shrink in computer chip feature sizes has been fueled over the years by a continual reduction in the wavelength of light used to pattern the chips. Recently, this trend has been threatened by unavailability of lens materials suitable for wavelengths shorter than 193 nm. To circumvent this roadblock, a reflective technology utilizing a significantly shorter extreme ultraviolet (EUV) wavelength (13.5 nm) has been under development for the pastmore » decade. The dramatic wavelength shrink was required to compensate for optical design limitations intrinsic in mirror-based systems compared to refractive lens systems. With this significant reduction in wavelength comes a variety of new challenges including developing sources of adequate power, photoresists with suitable resolution, sensitivity, and line-edge roughness characteristics, as well as the fabrication of reflection masks with zero defects. While source development can proceed in the absence of available exposure tools, in order for progress to be made in the areas of resists and masks it is crucial to have access to advanced exposure tools with resolutions equal to or better than that expected from initial production tools. These advanced development tools, however, need not be full field tools. Also, implementing such tools at synchrotron facilities allows them to be developed independent of the availability of reliable stand-alone BUY sources. One such tool is the SEMATECH Berkeley microfield exposure tool (MET). The most unique attribute of the SEMA TECH Berkeley MET is its use of a custom-coherence illuminator made possible by its implementation on a synchrotron beamline. With only conventional illumination and conventional binary masks, the resolution limit of the 0.3-NA optic is approximately 25 nm, however, with EUV not expected in production before the 22-nm half pitch node even finer resolution capabilities are now required from development tools. The SEMATECH Berkeley MET's custom-coherence illuminator allows it to be used with aggressive modified illumination enabling kJ factors as low as 0.25. Noting that the lithographic resolution of an exposure tool is defined as k{sub 1}{lambda}/NA, yielding an ultimate resolution limit of 11 nm. To achieve sub-20-nm aerial-image resolution while avoiding forbidden pitches on Manhattan-geometry features with the centrally-obscured MET optic, a 45-degree oriented dipole pupil fill is used. Figure 1 shows the computed aerial-image contrast as a function of half pitch for a dipole pupil fill optimized to print down to the 19-nm half pitch level. This is achieved with relatively uniform performance at larger dimensions. Using this illumination, printing down to the 20-nm half pitch level has been demonstrated in chemically amplified resists as shown in Fig. 2. The SEMATECH Berkeley MET tool plays a crucial role in the advancement of EUV resists. The unique programmable coherence properties of this tool enable it to achieve higher resolution than other EUV projection tools. As presented here, over the past year the tool has been used to demonstrate resist resolutions of 20 half pitch. Although not discussed here, because the Berkeley MET tool is a true projection lithography tool, it also plays a crucial role in advanced EUV mask research. Examples of the work done in this area include defect printability, mask architecture, and phase shift masks.« less

Nearly amorphous Mo-N gratings for ultimate resolution in extreme ultraviolet interference lithography.

PubMed

Wang, L; Kirk, E; Wäckerlin, C; Schneider, C W; Hojeij, M; Gobrecht, J; Ekinci, Y

2014-06-13

We present fabrication and characterization of high-resolution and nearly amorphous Mo1 - xNx transmission gratings and their use as masks for extreme ultraviolet (EUV) interference lithography. During sputter deposition of Mo, nitrogen is incorporated into the film by addition of N2 to the Ar sputter gas, leading to suppression of Mo grain growth and resulting in smooth and homogeneous thin films with a negligible grain size. The obtained Mo0.8N0.2 thin films, as determined by x-ray photoelectron spectroscopy, are characterized to be nearly amorphous using x-ray diffraction. We demonstrate a greatly reduced Mo0.8N0.2 grating line edge roughness compared with pure Mo grating structures after e-beam lithography and plasma dry etching. The amorphous Mo0.8N0.2 thin films retain, to a large extent, the benefits of Mo as a phase grating material for EUV wavelengths, providing great advantages for fabrication of highly efficient diffraction gratings with extremely low roughness. Using these grating masks, well-resolved dense lines down to 8 nm half-pitch are fabricated with EUV interference lithography.

Electrical comparison of iN7 EUV hybrid and EUV single patterning BEOL metal layers

NASA Astrophysics Data System (ADS)

Larivière, Stéphane; Wilson, Christopher J.; Kutrzeba Kotowska, Bogumila; Versluijs, Janko; Decoster, Stefan; Mao, Ming; van der Veen, Marleen H.; Jourdan, Nicolas; El-Mekki, Zaid; Heylen, Nancy; Kesters, Els; Verdonck, Patrick; Béral, Christophe; Van den Heuvel, Dieter; De Bisschop, Peter; Bekaert, Joost; Blanco, Victor; Ciofi, Ivan; Wan, Danny; Briggs, Basoene; Mallik, Arindam; Hendrickx, Eric; Kim, Ryoung-han; McIntyre, Greg; Ronse, Kurt; Bömmels, Jürgen; Tőkei, Zsolt; Mocuta, Dan

2018-03-01

The semiconductor scaling roadmap shows the continuous node to node scaling to push Moore's law down to the next generations. In that context, the foundry N5 node requires 32nm metal pitch interconnects for the advanced logic Back- End of Line (BEoL). 193immersion usage now requires self-aligned and/or multiple patterning technique combinations to enable such critical dimension. On the other hand, EUV insertion investigation shows that 32nm metal pitch is still a challenge but, related to process flow complexity, presents some clear motivations. Imec has already evaluated on test chip vehicles with different patterning approaches: 193i SAQP (Self-Aligned Quadruple Patterning), LE3 (triple patterning Litho Etch), tone inversion, EUV SE (Single Exposure) with SMO (Source-mask optimization). Following the run path in the technology development for EUV insertion, imec N7 platform (iN7, corresponding node to the foundry N5) is developed for those BEoL layers. In this paper, following technical motivation and development learning, a comparison between the iArF SAQP/EUV block hybrid integration scheme and a single patterning EUV flow is proposed. These two integration patterning options will be finally compared from current morphological and electrical criteria.

Take a byte out of MEEF: VAMPIRE: Vehicle for Advanced Mask Pattern Inspection Readiness Evaluations

NASA Astrophysics Data System (ADS)

Badger, Karen D.; Rankin, Jed; Turley, Christina; Seki, Kazunori; Dechene, Dan J.; Abdelghany, Hesham

2016-09-01

MEEF, or Mask Error Enhancement Factor, is simply defined as the ratio of the change in printed wafer feature width to the change in mask feature width scaled to wafer level. It is important in chip manufacturing that leads to the amplification of mask errors, creating challenges with both achieving dimensional control tolerances and ensuring defect free masks, as measured by on-wafer image quality. As lithographic imaging continues to be stressed, using lower and lower k1 factor resolution enhancement techniques, the high MEEF areas present on advanced optical masks creates an environment where the need for increased mask defect sensitivity in high-MEEF areas becomes more and more critical. There are multiple approaches to mask inspection that may or may not provide enough sensitivity to detect all wafer-printable defects; the challenge in the application of these techniques is simultaneously maintaining an acceptable level of mask inspectability. The higher the MEEF, the harder the challenge will be to achieve and appropriate level of sensitivity while maintaining inspectability…and to do so on the geometries that matter. The predominant photomask fabrication inspection approach in use today compares the features on the reticle directly with the design database using high-NA optics. This approach has the ability to detect small defects, however, when inspecting aggressive OPC, it can lead to the over-detection of inconsequential, or nuisance defects. To minimize these nuisance detections, changing the sensitivity of the inspection can improve the inspectability of a mask inspected in high-NA mode, however, it leads to the inability to detect subtle, yet wafer-printable defects in High-MEEF geometry, due to the fact that this `desense' must be applied globally. There are also `lithography-emulating' approaches to inspection that use various means to provide high defect sensitivity and the ability to tolerate inconsequential, non-printing defects by using scanner-like conditions to determine which defects are wafer printable. This inspection technique is commonly referred to as being `lithography plane' or `litho plane,' since it's assessing the mask quality based on how the mask appears to the imaging optics during use, as proposed to traditional `reticle plane' inspection which is comparing the mask only with its target design. Regardless of how the defects are detected, the real question is when should they be detected? For larger technology nodes, defects are considered `statistical risks'…i.e., first they have to occur, and then they have to fall in high-MEEF areas in order to be of concern, and be below the detection limits of traditional reticle-plane inspection. In short, the `perfect storm' has to happen in order to miss printable defects using well-optimized traditional inspection approaches. The introduction of lithographic inspection techniques has revealed this statistical game is a much higher risk than originally estimated, in that very subtle waferprintable CD errors typically fall into the desense band for traditional reticle plane inspection. Because printability is largely influenced by MEEF, designs with high-MEEF values are at greater risk of traditional inspection missing printable CD errors. The question is… how high is high… and at what MEEF is optical inspection at the reticle plane sufficient? This paper will provide evaluation results for both reticle-plane and litho-plane inspections as they pertain to varying degrees of MEEF. A newly designed high-MEEF programmed defect test mask, named VAMPIRE, will be introduced. This test mask is based on 7 nm node technology and contains intentionally varying degrees of MEEF as well as a variety of programmed defects in high-MEEF environments…all of which have been verified for defect lithographic significance on a Zeiss AIMS system.

EUVL Mask Blank Repair

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barty, A; Mirkarimi, P; Stearns, D G

2002-05-22

EUV mask blanks are fabricated by depositing a reflective Mo/Si multilayer film onto super-polished substrates. Small defects in this thin film coating can significantly alter the reflected field and introduce defects in the printed image. Ideally one would want to produce defect-free mask blanks; however, this may be very difficult to achieve in practice. One practical way to increase the yield of mask blanks is to effectively repair multilayer defects, and to this effect they present two complementary defect repair strategies for use on multilayer-coated EUVL mask blanks. A defect is any area on the mask which causes unwanted variationsmore » in EUV dose in the aerial image obtained in a printing tool, and defect repair is correspondingly defined as any strategy that renders a defect unprintable during exposure. The term defect mitigation can be adopted to describe any strategy which renders a critical defect non-critical when printed, and in this regard a non-critical defect is one that does not adversely affect device function. Defects in the patterned absorber layer consist of regions where metal, typically chrome, is unintentionally added or removed from the pattern leading to errors in the reflected field. There currently exists a mature technology based on ion beam milling and ion beam assisted deposition for repairing defects in the absorber layer of transmission lithography masks, and it is reasonable to expect that this technology will be extended to the repair of absorber defects in EUVL masks. However, techniques designed for the repair of absorber layers can not be directly applied to the repair of defects in the mask blank, and in particular the multilayer film. In this paper they present for the first time a new technique for the repair of amplitude defects as well as recent results on the repair of phase defects.« less

EUV microexposures at the ALS using the 0.3-NA MET projectionoptics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naulleau, Patrick; Goldberg, Kenneth A.; Anderson, Erik

2005-09-01

The recent development of high numerical aperture (NA) EUV optics such as the 0.3-NA Micro Exposure Tool (MET) optic has given rise to a new class of ultra-high resolution microexposure stations. Once such printing station has been developed and implemented at Lawrence Berkeley National Laboratory's Advanced Light Source. This flexible printing station utilizes a programmable coherence illuminator providing real-time pupil-fill control for advanced EUV resist and mask development. The Berkeley exposure system programmable illuminator enables several unique capabilities. Using dipole illumination out to {sigma}=1, the Berkeley tool supports equal-line-space printing down to 12 nm, well beyond the capabilities of similarmore » tools. Using small-sigma illumination combined with the central obscuration of the MET optic enables the system to print feature sizes that are twice as small as those coded on the mask. In this configuration, the effective 10x-demagnification for equal lines and spaces reduces the mask fabrication burden for ultra-high-resolution printing. The illuminator facilitates coherence studies such as the impact of coherence on line-edge roughness (LER) and flare. Finally the illuminator enables novel print-based aberration monitoring techniques as described elsewhere in these proceedings. Here we describe the capabilities of the new MET printing station and present system characterization results. Moreover, we present the latest printing results obtained in experimental resists. Limited by the availability of high-resolution photoresists, equal line-space printing down to 25 nm has been demonstrated as well as isolated line printing down to 29 nm with an LER of approaching 3 nm.« less

Quantitative phase retrieval with arbitrary pupil and illumination

DOE PAGES

Claus, Rene A.; Naulleau, Patrick P.; Neureuther, Andrew R.; ...

2015-10-02

We present a general algorithm for combining measurements taken under various illumination and imaging conditions to quantitatively extract the amplitude and phase of an object wave. The algorithm uses the weak object transfer function, which incorporates arbitrary pupil functions and partially coherent illumination. The approach is extended beyond the weak object regime using an iterative algorithm. Finally, we demonstrate the method on measurements of Extreme Ultraviolet Lithography (EUV) multilayer mask defects taken in an EUV zone plate microscope with both a standard zone plate lens and a zone plate implementing Zernike phase contrast.

Edge placement error control and Mask3D effects in High-NA anamorphic EUV lithography

NASA Astrophysics Data System (ADS)

van Setten, Eelco; Bottiglieri, Gerardo; de Winter, Laurens; McNamara, John; Rusu, Paul; Lubkoll, Jan; Rispens, Gijsbert; van Schoot, Jan; Neumann, Jens Timo; Roesch, Matthias; Kneer, Bernhard

2017-10-01

To enable cost-effective shrink at the 3nm node and beyond, and to extend Moore's law into the next decade, ASML is developing a new high-NA EUV platform. The high-NA system is targeted to feature a numerical aperture (NA) of 0.55 to extend the single exposure resolution limit to 8nm half pitch. The system is being designed to achieve an on-product-overlay (OPO) performance well below 2nm, a high image contrast to drive down local CD errors and to obtain global CDU at sub-1nm level to be able to meet customer edge placement error (EPE) requirements for the devices of the future. EUV scanners employ reflective Bragg multi-layer mirrors in the mask and in the Projection Optics Box (POB) that is used to project the mask pattern into the photoresist on the silicon wafer. These MoSi multi-layer mirrors are tuned for maximum reflectivity, and thus productivity, at 13.5nm wavelength. The angular range of incident light for which a high reflectivity at the reticle can be obtained is limited to +/- 11o, exceeding the maximum angle occurring in current 0.33NA scanners at 4x demagnification. At 0.55NA the maximum angle at reticle level would extend up to 17o in the critical (scanning) direction and compromise the imaging performance of horizontal features severely. To circumvent this issue a novel anamorphic optics design has been introduced, which has a 4x demagnification in the X- (slit) direction and 8x demagnification in the Y- (scanning) direction as well as a central obscuration in the exit pupil. In this work we will show that the EUV high-NA anamorphic concept can successfully solve the angular reflectivity issues and provide good imaging performance in both directions. Several unique imaging challenges in comparison to the 0.33NA isomorphic baseline are being studied, such as the impact of the central obscuration in the POB and Mask-3D effects at increased NA that seem most pronounced for vertical features. These include M3D induced contrast loss and non-telecentricity. We will explore the solutions needed to mitigate these effects and to offer high quality imaging to be able to meet the required EPE performance in both orientations.

Mask automation: need a revolution in mask makers and equipment industry

NASA Astrophysics Data System (ADS)

Moon, Seong-yong; Yu, Sang-yong; Noh, Young-hwa; Son, Ki-jung; Lee, Hyun-Joo; Cho, Han-Ku

2013-09-01

As improving device integration for the next generation, high performance and cost down are also required accordingly in semiconductor business. Recently, significant efforts have been given on putting EUV technology into fabrication in order to improve device integration. At the same time, 450mm wafer manufacturing environment has been considered seriously in many ways in order to boost up the productivity. Accordingly, 9-inch mask has been discussed in mask fabrication business recently to support 450mm wafer manufacturing environment successfully. Although introducing 9-inch mask can be crucial for mask industry, multi-beam technology is also expected as another influential turning point to overcome currently the most critical issue in mask industry, electron beam writing time. No matter whether 9-inch mask or multi-beam technology will be employed or not, mask quality and productivity will be the key factors to survive from the device competition. In this paper, the level of facility automation in mask industry is diagnosed and analyzed and the automation guideline is suggested for the next generation.

From powerful research platform for industrial EUV photoresist development, to world record resolution by photolithography: EUV interference lithography at the Paul Scherrer Institute

NASA Astrophysics Data System (ADS)

Buitrago, Elizabeth; Fallica, Roberto; Fan, Daniel; Karim, Waiz; Vockenhuber, Michaela; van Bokhoven, Jeroen A.; Ekinci, Yasin

2016-09-01

Extreme ultraviolet interference lithography (EUV-IL, λ = 13.5 nm) has been shown to be a powerful technique not only for academic, but also for industrial research and development of EUV materials due to its relative simplicity yet record high-resolution patterning capabilities. With EUV-IL, it is possible to pattern high-resolution periodic images to create highly ordered nanostructures that are difficult or time consuming to pattern by electron beam lithography (EBL) yet interesting for a wide range of applications such as catalysis, electronic and photonic devices, and fundamental materials analysis, among others. Here, we will show state-of the-art research performed using the EUV-IL tool at the Swiss Light Source (SLS) synchrotron facility in the Paul Scherrer Institute (PSI). For example, using a grating period doubling method, a diffraction mask capable of patterning a world record in photolithography of 6 nm half-pitch (HP), was produced. In addition to the description of the method, we will give a few examples of applications of the technique. Well-ordered arrays of suspended silicon nanowires down to 6.5 nm linewidths have been fabricated and are to be studied as field effect transistors (FETs) or biosensors, for instance. EUV achromatic Talbot lithography (ATL), another interference scheme that utilizes a single grating, was shown to yield well-defined nanoparticles over large-areas with high uniformity presenting great opportunities in the field of nanocatalysis. EUV-IL is in addition, playing a key role in the future introduction of EUV lithography into high volume manufacturing (HVM) of semiconductor devices for the 7 and 5 nm logic node (16 nm and 13 nm HP, respectively) and beyond while the availability of commercial EUV-tools is still very much limited for research.

Defect inspection and printability study for 14 nm node and beyond photomask

NASA Astrophysics Data System (ADS)

Seki, Kazunori; Yonetani, Masashi; Badger, Karen; Dechene, Dan J.; Akima, Shinji

2016-10-01

Two different mask inspection techniques are developed and compared for 14 nm node and beyond photomasks, High resolution and Litho-based inspection. High resolution inspection is the general inspection method in which a 19x nm wavelength laser is used with the High NA inspection optics. Litho-based inspection is a new inspection technology. This inspection uses the wafer lithography information, and as such, this method has automatic defect classification capability which is based on wafer printability. Both High resolution and Litho-based inspection methods are compared using 14 nm and 7 nm node programmed defect and production design masks. The defect sensitivity and mask inspectability is compared, in addition to comparing the defect classification and throughput. Additionally, the Cost / Infrastructure comparison is analyzed and the impact of each inspection method is discussed.

Resist Parameter Extraction from Line-and-Space Patterns of Chemically Amplified Resist for Extreme Ultraviolet Lithography

NASA Astrophysics Data System (ADS)

Kozawa, Takahiro; Oizumi, Hiroaki; Itani, Toshiro; Tagawa, Seiichi

2010-11-01

The development of extreme ultraviolet (EUV) lithography has progressed owing to worldwide effort. As the development status of EUV lithography approaches the requirements for the high-volume production of semiconductor devices with a minimum line width of 22 nm, the extraction of resist parameters becomes increasingly important from the viewpoints of the accurate evaluation of resist materials for resist screening and the accurate process simulation for process and mask designs. In this study, we demonstrated that resist parameters (namely, quencher concentration, acid diffusion constant, proportionality constant of line edge roughness, and dissolution point) can be extracted from the scanning electron microscopy (SEM) images of patterned resists without the knowledge on the details of resist contents using two types of latest EUV resist.

On numerical reconstructions of lithographic masks in DUV scatterometry

NASA Astrophysics Data System (ADS)

Henn, M.-A.; Model, R.; Bär, M.; Wurm, M.; Bodermann, B.; Rathsfeld, A.; Gross, H.

2009-06-01

The solution of the inverse problem in scatterometry employing deep ultraviolet light (DUV) is discussed, i.e. we consider the determination of periodic surface structures from light diffraction patterns. With decreasing dimensions of the structures on photo lithography masks and wafers, increasing demands on the required metrology techniques arise. Scatterometry as a non-imaging indirect optical method is applied to periodic line structures in order to determine the sidewall angles, heights, and critical dimensions (CD), i.e., the top and bottom widths. The latter quantities are typically in the range of tens of nanometers. All these angles, heights, and CDs are the fundamental figures in order to evaluate the quality of the manufacturing process. To measure those quantities a DUV scatterometer is used, which typically operates at a wavelength of 193 nm. The diffraction of light by periodic 2D structures can be simulated using the finite element method for the Helmholtz equation. The corresponding inverse problem seeks to reconstruct the grating geometry from measured diffraction patterns. Fixing the class of gratings and the set of measurements, this inverse problem reduces to a finite dimensional nonlinear operator equation. Reformulating the problem as an optimization problem, a vast number of numerical schemes can be applied. Our tool is a sequential quadratic programing (SQP) variant of the Gauss-Newton iteration. In a first step, in which we use a simulated data set, we investigate how accurate the geometrical parameters of an EUV mask can be reconstructed, using light in the DUV range. We then determine the expected uncertainties of geometric parameters by reconstructing from simulated input data perturbed by noise representing the estimated uncertainties of input data. In the last step, we use the measurement data obtained from the new DUV scatterometer at PTB to determine the geometrical parameters of a typical EUV mask with our reconstruction algorithm. The results are compared to the outcome of investigations with two alternative methods namely EUV scatterometry and SEM measurements.

The future of EUV lithography: enabling Moore's Law in the next decade

NASA Astrophysics Data System (ADS)

Pirati, Alberto; van Schoot, Jan; Troost, Kars; van Ballegoij, Rob; Krabbendam, Peter; Stoeldraijer, Judon; Loopstra, Erik; Benschop, Jos; Finders, Jo; Meiling, Hans; van Setten, Eelco; Mika, Niclas; Dredonx, Jeannot; Stamm, Uwe; Kneer, Bernhard; Thuering, Bernd; Kaiser, Winfried; Heil, Tilmann; Migura, Sascha

2017-03-01

While EUV systems equipped with a 0.33 Numerical Aperture lenses are readying to start volume manufacturing, ASML and Zeiss are ramping up their development activities on a EUV exposure tool with Numerical Aperture greater than 0.5. The purpose of this scanner, targeting a resolution of 8nm, is to extend Moore's law throughout the next decade. A novel, anamorphic lens design, has been developed to provide the required Numerical Aperture; this lens will be paired with new, faster stages and more accurate sensors enabling Moore's law economical requirements, as well as the tight focus and overlay control needed for future process nodes. The tighter focus and overlay control budgets, as well as the anamorphic optics, will drive innovations in the imaging and OPC modelling, and possibly in the metrology concepts. Furthermore, advances in resist and mask technology will be required to image lithography features with less than 10nm resolution. This paper presents an overview of the key technology innovations and infrastructure requirements for the next generation EUV systems.

Optical proximity correction for anamorphic extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

Clifford, Chris; Lam, Michael; Raghunathan, Ananthan; Jiang, Fan; Fenger, Germain; Adam, Kostas

2017-10-01

The change from isomorphic to anamorphic optics in high numerical aperture (NA) extreme ultraviolet (EUV) scanners necessitates changes to the mask data preparation flow. The required changes for each step in the mask tape out process are discussed, with a focus on optical proximity correction (OPC). When necessary, solutions to new problems are demonstrated, and verified by rigorous simulation. Additions to the OPC model include accounting for anamorphic effects in the optics, mask electromagnetics, and mask manufacturing. The correction algorithm is updated to include awareness of anamorphic mask geometry for mask rule checking (MRC). OPC verification through process window conditions is enhanced to test different wafer scale mask error ranges in the horizontal and vertical directions. This work will show that existing models and methods can be updated to support anamorphic optics without major changes. Also, the larger mask size in the Y direction can result in better model accuracy, easier OPC convergence, and designs which are more tolerant to mask errors.

Particle control near reticle and optics using showerhead

DOEpatents

Delgado, Gildardo R.; Chilese, Frank; Garcia, Rudy; Torczynski, John R.; Geller, Anthony S.; Rader, Daniel J.; Klebanoff, Leonard E.; Gallis, Michail A.

2016-01-26

A method and an apparatus to protect a reticle against particles and chemicals in an actinic EUV reticle inspection tool are presented. The method and apparatus utilizes a pair of porous metal diffusers in the form of showerheads to provide a continual flow of clean gas. The main showerhead bathes the reticle surface to be inspected in smoothly flowing, low pressure gas, isolating it from particles coming from surrounding volumes. The secondary showerhead faces away from the reticle and toward the EUV illumination and projection optics, supplying them with purge gas while at the same time creating a buffer zone that is kept free of any particle contamination originating from those optics.

Design requirements for a stand alone EUV interferometer

NASA Astrophysics Data System (ADS)

Michallon, Ph.; Constancias, C.; Lagrange, A.; Dalzotto, B.

2008-03-01

EUV lithography is expected to be inserted for the 32/22 nm nodes with possible extension below. EUV resist availability remains one of the main issues to be resolved. There is an urgent need to provide suitable tools to accelerate resist development and to achieve resolution, LER and sensitivity specifications simultaneously. An interferometer lithography tool offers advantages regarding conventional EUV exposure tool. It allows the evaluation of resists, free from the deficiencies of optics and mask which are limiting the achieved resolution. Traditionally, a dedicated beam line from a synchrotron, with limited access, is used as a light source in EUV interference lithography. This paper identifies the technology locks to develop a stand alone EUV interferometer using a compact EUV source. It will describe the theoretical solutions adopted and especially look at the feasibility according to available technologies. EUV sources available on the market have been evaluated in terms of power level, source size, spatial coherency, dose uniformity, accuracy, stability and reproducibility. According to the EUV source characteristics, several optic designs were studied (simple or double gratings). For each of these solutions, the source and collimation optic specifications have been determined. To reduce the exposure time, a new grating technology will also be presented allowing to significantly increasing the transmission system efficiency. The optical grating designs were studied to allow multi-pitch resolution print on the same exposure without any focus adjustment. Finally micro mechanical system supporting the gratings was studied integrating the issues due to vacuum environment, alignment capability, motion precision, automation and metrology to ensure the needed placement control between gratings and wafer. A similar study was carried out for the collimation-optics mechanical support which depends on the source characteristics.

Defect tolerant transmission lithography mask

DOEpatents

Vernon, Stephen P.

2000-01-01

A transmission lithography mask that utilizes a transparent substrate or a partially transparent membrane as the active region of the mask. A reflective single layer or multilayer coating is deposited on the membrane surface facing the illumination system. The coating is selectively patterned (removed) to form transmissive (bright) regions. Structural imperfections and defects in the coating have negligible effect on the aerial image of the mask master pattern since the coating is used to reflect radiation out of the entrance pupil of the imaging system. Similarly, structural imperfections in the clear regions of the membrane have little influence on the amplitude or phase of the transmitted electromagnetic fields. Since the mask "discards," rather than absorbs, unwanted radiation, it has reduced optical absorption and reduced thermal loading as compared to conventional designs. For EUV applications, the mask circumvents the phase defect problem, and is independent of the thermal load during exposure.

Interferometric at-wavelength flare characterization of EUV optical systems

DOEpatents

Naulleau, Patrick P.; Goldberg, Kenneth Alan

2001-01-01

The extreme ultraviolet (EUV) phase-shifting point diffraction interferometer (PS/PDI) provides the high-accuracy wavefront characterization critical to the development of EUV lithography systems. Enhancing the implementation of the PS/PDI can significantly extend its spatial-frequency measurement bandwidth. The enhanced PS/PDI is capable of simultaneously characterizing both wavefront and flare. The enhanced technique employs a hybrid spatial/temporal-domain point diffraction interferometer (referred to as the dual-domain PS/PDI) that is capable of suppressing the scattered-reference-light noise that hinders the conventional PS/PDI. Using the dual-domain technique in combination with a flare-measurement-optimized mask and an iterative calculation process for removing flare contribution caused by higher order grating diffraction terms, the enhanced PS/PDI can be used to simultaneously measure both figure and flare in optical systems.

Prospect of EUV mask repair technology using e-beam tool

NASA Astrophysics Data System (ADS)

Kanamitsu, Shingo; Hirano, Takashi; Suga, Osamu

2010-09-01

Currently, repair machines used for advanced photomasks utilize principle method like as FIB, AFM, and EB. There are specific characteristic respectively, thus they have an opportunity to be used in suitable situation. But when it comes to EUV generation, pattern size is so small highly expected as under 80nm that higher image resolution and repair accuracy is needed for its machines. Because FIB machine has intrinsic damage problem induced by Ga ion and AFM machine has critical tip size issue, those machines are basically difficult to be applied for EUV generation. Consequently, we focused on EB repair tool for research work. EB repair tool has undergone practical milestone about MoSi based masks. We have applied same process which is used for MoSi to EUV blank and confirmed its reaction. Then we found some severe problems which show uncontrollable feature due to its enormously strong reaction between etching gas and absorber material. Though we could etch opaque defect with conventional method and get the edge shaped straight by top-down SEM viewing, there were problems like as sidewall undercut or local erosion depending on defect shape. In order to cope with these problems, the tool vender has developed a new process and reported it through an international conference [1]. We have evaluated the new process mentioned above in detail. In this paper, we will bring the results of those evaluations. Several experiments for repair accuracy, process stability, and other items have been done under estimation of practical condition assuming diversified size and shape defects. A series of actual printability tests will be also included. On the basis of these experiments, we consider the possibility of EB-repair application for 20nm pattern.

Emulation of anamorphic imaging on the SHARP extreme ultraviolet mask microscope

DOE PAGES

Benk, Markus P.; Wojdyla, Antoine; Chao, Weilun; ...

2016-07-12

The SHARP high-numerical aperture actinic reticle review project is a synchrotron-based, extreme ultraviolet (EUV) microscope dedicated to photomask research. SHARP emulates the illumination and imaging conditions of current EUV lithography scanners and those several generations into the future. An anamorphic imaging optic with increased mask-side numerical aperture (NA) in the horizontal and increased demagnification in the vertical direction has been proposed in this paper to overcome limitations of current multilayer coatings and extend EUV lithography beyond 0.33 NA. Zoneplate lenses with an anamorphic 4×/8× NA of 0.55 are fabricated and installed in the SHARP microscope to emulate anamorphic imaging. SHARP’smore » Fourier synthesis illuminator with a range of angles exceeding the collected solid angle of the newly designed elliptical zoneplates can produce arbitrary angular source spectra matched to anamorphic imaging. A target with anamorphic dense features down to 50-nm critical dimension is fabricated using 40 nm of nickel as the absorber. In a demonstration experiment, anamorphic imaging at 0.55 4×/8× NA and 6 deg central ray angle (CRA) is compared with conventional imaging at 0.5 4× NA and 8 deg CRA. A significant contrast loss in horizontal features is observed in the conventional images. Finally, the anamorphic images show the same image quality in the horizontal and vertical directions.« less

Emulation of anamorphic imaging on the SHARP extreme ultraviolet mask microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benk, Markus P.; Wojdyla, Antoine; Chao, Weilun

The SHARP high-numerical aperture actinic reticle review project is a synchrotron-based, extreme ultraviolet (EUV) microscope dedicated to photomask research. SHARP emulates the illumination and imaging conditions of current EUV lithography scanners and those several generations into the future. An anamorphic imaging optic with increased mask-side numerical aperture (NA) in the horizontal and increased demagnification in the vertical direction has been proposed in this paper to overcome limitations of current multilayer coatings and extend EUV lithography beyond 0.33 NA. Zoneplate lenses with an anamorphic 4×/8× NA of 0.55 are fabricated and installed in the SHARP microscope to emulate anamorphic imaging. SHARP’smore » Fourier synthesis illuminator with a range of angles exceeding the collected solid angle of the newly designed elliptical zoneplates can produce arbitrary angular source spectra matched to anamorphic imaging. A target with anamorphic dense features down to 50-nm critical dimension is fabricated using 40 nm of nickel as the absorber. In a demonstration experiment, anamorphic imaging at 0.55 4×/8× NA and 6 deg central ray angle (CRA) is compared with conventional imaging at 0.5 4× NA and 8 deg CRA. A significant contrast loss in horizontal features is observed in the conventional images. Finally, the anamorphic images show the same image quality in the horizontal and vertical directions.« less

High-NA EUV lithography enabling Moore's law in the next decade

NASA Astrophysics Data System (ADS)

van Schoot, Jan; Troost, Kars; Bornebroek, Frank; van Ballegoij, Rob; Lok, Sjoerd; Krabbendam, Peter; Stoeldraijer, Judon; Loopstra, Erik; Benschop, Jos P.; Finders, Jo; Meiling, Hans; van Setten, Eelco; Kneer, Bernhard; Kuerz, Peter; Kaiser, Winfried; Heil, Tilmann; Migura, Sascha; Neumann, Jens Timo

2017-10-01

While EUV systems equipped with a 0.33 Numerical Aperture lenses are readying to start volume manufacturing, ASML and Zeiss are ramping up their activities on a EUV exposure tool with Numerical Aperture of 0.55. The purpose of this scanner, targeting an ultimate resolution of 8nm, is to extend Moore's law throughout the next decade. A novel, anamorphic lens design, capable of providing the required Numerical Aperture has been investigated; This lens will be paired with new, faster stages and more accurate sensors enabling Moore's law economical requirements, as well as the tight focus and overlay control needed for future process nodes. The tighter focus and overlay control budgets, as well as the anamorphic optics, will drive innovations in the imaging and OPC modelling. Furthermore, advances in resist and mask technology will be required to image lithography features with less than 10nm resolution. This paper presents an overview of the target specifications, key technology innovations and imaging simulations demonstrating the advantages as compared to 0.33NA and showing the capabilities of the next generation EUV systems.

Inspection of lithographic mask blanks for defects

DOEpatents

Sommargren, Gary E.

2001-01-01

A visible light method for detecting sub-100 nm size defects on mask blanks used for lithography. By using optical heterodyne techniques, detection of the scattered light can be significantly enhanced as compared to standard intensity detection methods. The invention is useful in the inspection of super-polished surfaces for isolated surface defects or particulate contamination and in the inspection of lithographic mask or reticle blanks for surface defects or bulk defects or for surface particulate contamination.

High-numerical aperture extreme ultraviolet scanner for 8-nm lithography and beyond

NASA Astrophysics Data System (ADS)

Schoot, Jan van; Setten, Eelco van; Rispens, Gijsbert; Troost, Kars Z.; Kneer, Bernhard; Migura, Sascha; Neumann, Jens Timo; Kaiser, Winfried

2017-10-01

Current extreme ultraviolet (EUV) projection lithography systems exploit a projection lens with a numerical aperture (NA) of 0.33. It is expected that these will be used in mass production in the 2018/2019 timeframe. By then, the most difficult layers at the 7-nm logic and the mid-10-nm DRAM nodes will be exposed. These systems are a more economical alternative to multiple-exposure by 193 argon fluoride immersion scanners. To enable cost-effective shrink by EUV lithography down to 8-nm half pitch, a considerably larger NA is needed. As a result of the increased NA, the incidence angles of the light rays at the mask increase significantly. Consequently, the shadowing and the variation of the multilayer reflectivity deteriorate the aerial image contrast to unacceptably low values at the current 4× magnification. The only solution to reduce the angular range at the mask is to increase the magnification. Simulations show that the magnification has to be doubled to 8× to overcome the shadowing effects. Assuming that the mask infrastructure will not change the mask form factor, this would inevitably lead to a field size that is a quarter of the field size of the current 0.33-NA step and scan systems and reduce the throughput (TPT) of the high-NA scanner to a value below 100 wafers per hour unless additional measures are taken. This paper presents an anamorphic step and scan system capable of printing fields that are half the field size of the current full field. The anamorphic system has the potential to achieve a TPT in excess of 150 wafers per hour by increasing the transmission of the optics, as well as increasing the acceleration of the wafer stage and mask stage. This makes it an economically viable lithography solution.

Multilayer films with sharp, stable interfaces for use in EUV and soft X-ray application

DOEpatents

Barbee, Jr., Troy W.; Bajt, Sasa

2002-01-01

The reflectivity and thermal stability of Mo/Si (molybdenum/silicon) multilayer films, used in soft x-ray and extreme ultraviolet region, is enhanced by deposition of a thin layer of boron carbide (e.g., B.sub.4 C) between alternating layers of Mo and Si. The invention is useful for reflective coatings for soft X-ray and extreme ultraviolet optics, multilayer for masks, coatings for other wavelengths and multilayers for masks that are more thermally stable than pure Mo/Si multilayers

Impact of deformed extreme-ultraviolet pellicle in terms of CD uniformity

NASA Astrophysics Data System (ADS)

Kim, In-Seon; Yeung, Michael; Barouch, Eytan; Oh, Hye-Keun

2015-07-01

The usage of the extreme ultraviolet (EUV) pellicle is regarded as the solution for defect control since it can protect the mask from airborne debris. However some obstacles disrupt real-application of the pellicle such as structural weakness, thermal damage and so on. For these reasons, flawless fabrication of the pellicle is impossible. In this paper, we discuss the influence of deformed pellicle in terms of non-uniform intensity distribution and critical dimension (CD) uniformity. It was found that non-uniform intensity distribution is proportional to local tilt angle of pellicle and CD variation was linearly proportional to transmission difference. When we consider the 16 nm line and space pattern with dipole illumination (σc=0.8, σr=0.1, NA=0.33), the transmission difference (max-min) of 0.7 % causes 0.1 nm CD uniformity. Influence of gravity caused deflection to the aerial image is small enough to ignore. CD uniformity is less than 0.1 nm even for the current gap of 2 mm between mask and pellicle. However, heat caused EUV pellicle wrinkle might cause serious image distortion because a wrinkle of EUV pellicle causes a transmission loss variation as well as CD non-uniformity. In conclusion, local angle of a wrinkle, not a period or an amplitude of a wrinkle is a main factor to CD uniformity, and local angle of less than ~270 mrad is needed to achieve 0.1 nm CD uniformity with 16 nm L/S pattern.

Characteristics and issues of an EUVL mask applying phase-shifting thinner absorber for device fabrication

NASA Astrophysics Data System (ADS)

Seo, Hwan-Seok; Lee, Dong-Gun; Ahn, Byung-Sup; Han, Hakseung; Huh, Sungmin; Kang, In-Yong; Kim, Hoon; Kim, Dongwan; Kim, Seong-Sue; Cho, Han-Ku

2009-03-01

Phase-shifting EUVL masks applying thinner absorber are investigated to design optimum mask structure with less shadowing problems. Simulations using S-Litho show that H-V bias in Si capping structure is higher than that of Ru capping since the high n (= 0.999) of Si increases sensible absorber height. Phase differences obtained from the patterned masks using the EUV CSM are well-matched with the calculated values using the practical refractive index of absorber materials. Although the mask with 62.4-nm-thick absorber, among the in-house masks, shows the closest phase ΔΦ(= 176°) to the out-of-phase condition, higher NILS and contrast as well as lower H-V bias are obtained with 52.4-nm-thick absorber (ΔΦ = 151°) which has higher R/R0 ratio. MET results also show that lithography performances including MEEF, PW, and resist threshold (dose), are improved with thinner absorber structure. However, low OD in EUVL mask, especially in thinner absorber structure, results in light leakage from the neighboring exposure shots, and thus an appropriate light-shielding layer should be introduced.

Detecting Submicron Pattern Defects On Optical Photomasks Using An Enhanced El-3 Electron-Beam Lithography Tool

NASA Astrophysics Data System (ADS)

Simpson, R. A.; Davis, D. E.

1982-09-01

This paper describes techniques to detect submicron pattern defects on optical photomasks with an enhanced direct-write, electron-beam lithographic tool. EL-3 is a third generation, shaped spot, electron-beam lithography tool developed by IBM to fabricate semiconductor devices and masks. This tool is being upgraded to provide 100% inspection of optical photomasks for submicron pattern defects, which are subsequently repaired. Fixed-size overlapped spots are stepped over the mask patterns while a signal derived from the back-scattered electrons is monitored to detect pattern defects. Inspection does not require pattern recognition because the inspection scan patterns are derived from the original design data. The inspection spot is square and larger than the minimum defect to be detected, to improve throughput. A new registration technique provides the beam-to-pattern overlay required to locate submicron defects. The 'guard banding" of inspection shapes prevents mask and system tolerances from producing false alarms that would occur should the spots be mispositioned such that they only partially covered a shape being inspected. A rescanning technique eliminates noise-related false alarms and significantly improves throughput. Data is accumulated during inspection and processed offline, as required for defect repair. EL-3 will detect 0.5 um pattern defects at throughputs compatible with mask manufacturing.

High-volume manufacturing compatible dry development rinse process (DDRP): patterning and defectivity performance for EUVL

NASA Astrophysics Data System (ADS)

Sayan, Safak; Vanelderen, Pieter; Hetel, Iulian; Chan, BT; Raghavan, Praveen; Blanco, Victor; Foubert, Philippe; D'urzo, Lucia; De Simone, Danilo; Vandenberghe, Geert

2017-04-01

There are many knobs available that change the chemical and physical properties of the photoresists to "break" the RLS (Resolution, Sensitivity, Line edge/width roughness) trade-off, however those are not enough today to realize a material to satisfy all requirements at once for 7nm technology and beyond. DDRP improves the ultimate achievable resolution via pattern collapse mitigation, hence the priority of requirements for the EUV photoresist development may be changed with more focus on Sensitivity and LWR. This may potentially provide a new conceptual approach towards EUV PR development for DDRP applications. We have previously demonstrated pattern collapse (PC) mitigation via DDRP on different EUVL photoresists (including different resist platforms), achieving ultimate resolution and exposure latitude improvements [1,2]. In this contribution, we report patterning and material defect performance of HVM compatible (all aqueous) dry development rinse material. We will also report on process window improvement on 2-dimensional metal structures towards standard cell size reduction with elimination of mask layer(s) using single EUV exposure.

Method for fabricating an ultra-low expansion mask blank having a crystalline silicon layer

DOEpatents

Cardinale, Gregory F.

2002-01-01

A method for fabricating masks for extreme ultraviolet lithography (EUVL) using Ultra-Low Expansion (ULE) substrates and crystalline silicon. ULE substrates are required for the necessary thermal management in EUVL mask blanks, and defect detection and classification have been obtained using crystalline silicon substrate materials. Thus, this method provides the advantages for both the ULE substrate and the crystalline silicon in an Extreme Ultra-Violet (EUV) mask blank. The method is carried out by bonding a crystalline silicon wafer or member to a ULE wafer or substrate and thinning the silicon to produce a 5-10 .mu.m thick crystalline silicon layer on the surface of the ULE substrate. The thinning of the crystalline silicon may be carried out, for example, by chemical mechanical polishing and if necessary or desired, oxidizing the silicon followed by etching to the desired thickness of the silicon.

Dry etching technologies for the advanced binary film

NASA Astrophysics Data System (ADS)

Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Yoshimori, Tomoaki; Azumano, Hidehito; Muto, Makoto; Nonaka, Mikio

2011-11-01

ABF (Advanced Binary Film) developed by Hoya as a photomask for 32 (nm) and larger specifications provides excellent resistance to both mask cleaning and 193 (nm) excimer laser and thereby helps extend the lifetime of the mask itself compared to conventional photomasks and consequently reduces the semiconductor manufacturing cost [1,2,3]. Because ABF uses Ta-based films, which are different from Cr film or MoSi films commonly used for photomask, a new process is required for its etching technology. A patterning technology for ABF was established to perform the dry etching process for Ta-based films by using the knowledge gained from absorption layer etching for EUV mask that required the same Ta-film etching process [4]. Using the mask etching system ARES, which is manufactured by Shibaura Mechatronics, and its optimized etching process, a favorable CD (Critical Dimension) uniformity, a CD linearity and other etching characteristics were obtained in ABF patterning. Those results are reported here.

Physical resist models and their calibration: their readiness for accurate EUV lithography simulation

NASA Astrophysics Data System (ADS)

Klostermann, U. K.; Mülders, T.; Schmöller, T.; Lorusso, G. F.; Hendrickx, E.

2010-04-01

In this paper, we discuss the performance of EUV resist models in terms of predictive accuracy, and we assess the readiness of the corresponding model calibration methodology. The study is done on an extensive OPC data set collected at IMEC for the ShinEtsu resist SEVR-59 on the ASML EUV Alpha Demo Tool (ADT), with the data set including more than thousand CD values. We address practical aspects such as the speed of calibration and selection of calibration patterns. The model is calibrated on 12 process window data series varying in pattern width (32, 36, 40 nm), orientation (H, V) and pitch (dense, isolated). The minimum measured feature size at nominal process condition is a 32 nm CD at a dense pitch of 64 nm. Mask metrology is applied to verify and eventually correct nominal width of the drawn CD. Cross-sectional SEM information is included in the calibration to tune the simulated resist loss and sidewall angle. The achieved calibration RMS is ~ 1.0 nm. We show what elements are important to obtain a well calibrated model. We discuss the impact of 3D mask effects on the Bossung tilt. We demonstrate that a correct representation of the flare level during the calibration is important to achieve a high predictability at various flare conditions. Although the model calibration is performed on a limited subset of the measurement data (one dimensional structures only), its accuracy is validated based on a large number of OPC patterns (at nominal dose and focus conditions) not included in the calibration; validation RMS results as small as 1 nm can be reached. Furthermore, we study the model's extendibility to two-dimensional end of line (EOL) structures. Finally, we correlate the experimentally observed fingerprint of the CD uniformity to a model, where EUV tool specific signatures are taken into account.

Direct Mask Overlay Inspection

NASA Astrophysics Data System (ADS)

Hsia, Liang-Choo; Su, Lo-Soun

1983-11-01

In this paper, we present a mask inspection methodology and procedure that involves direct X-Y measurements. A group of dice is selected for overlay measurement; four measurement targets were laid out in the kerf of each die. The measured coordinates are then fit-ted to either a "historical" grid, which reflects the individual tool bias, or to an ideal grid squares fashion. Measurements are done using a Nikon X-Y laser interferometric measurement system, which provides a reference grid. The stability of the measurement system is essential. We then apply appropriate statistics to the residual after the fit to determine the overlay performance. Statistical methods play an important role in the product disposition. The acceptance criterion is, however, a compromise between the cost for mask making and the final device yield. In order to satisfy the demand on mask houses for quality of masks and high volume, mixing lithographic tools in mask making has become more popular, in particular, mixing optical and E-beam tools. In this paper, we also discuss the inspection procedure for mixing different lithographic tools.

Generation of warm dense matter using an argon based capillary discharge laser

NASA Astrophysics Data System (ADS)

Rossall, A. K.; Tallents, G. J.

2015-06-01

Argon based capillary discharge lasers operating in the extreme ultra violet (EUV) at 46.9 nm with output up to 0.5 mJ energy per pulse and repetition rates up to 10 Hz are capable of focused irradiances of 109-1012 W cm-2 and can be used to generate plasma in the warm dense matter regime by irradiating solid material. To model the interaction between such an EUV laser and solid material, the 2D radiative-hydrodynamic code POLLUX has been modified to include absorption via direct photo-ionisation, a super-configuration model to describe the ionization-dependent electronic configurations and a calculation of plasma refractive indices for ray tracing of the incident EUV laser radiation. A simulation study is presented, demonstrating how capillary discharge lasers of 1200 ps pulse duration can be used to generate warm dense matter at close to solid densities with temperatures of a few eV and energy densities up to 1 × 105 J cm-3. Plasmas produced by EUV laser irradiation are shown to be useful for examining the properties of warm dense matter as, for example, plasma emission is not masked by hotter, less dense plasma emission that occurs with visible/infra-red laser target irradiation.

Reticle decision center: a novel applications platform for enhancing reticle yield and productivity at 10nm technology and beyond

NASA Astrophysics Data System (ADS)

Hwa, George; Bugata, Raj; Chiang, Kaiming; Lakkapragada, Suresh; Tolani, Vikram; Gopalakrishnan, Sandhya; Chen, Chun-Jen; Yang, Chin-Ting; Hsu, Sheng-Chang; Tuo, Laurent

2016-10-01

In the semiconductor IC manufacturing industry, challenges associated with producing defect-free photomasks have been dramatically increasing. At the 10nm technology node, since the 193nm immersion scanner numerical aperture has remained the same 1.35 as in previous nodes, more multi-patterning and aggressive SMO illumination sources are being used to effectively print smaller feature CDs and pitches. To accommodate such specialized sources, more model-based mask OPC and ILT have been used making mask designs very complicated. This in turn makes mask manufacturing very challenging especially for the defect inspection, repair, and metrology processes that need to guarantee defect-free masks. Over the past few years, considerable innovation have been made in the areas of defect inspection and disposition that has ensured continued predictability of mask quality to wafer and final chip yields. The accurate disposition of each mask defect before and after repair has been facilitated by a suite of automated applications such as ADC, LPR, RPG, AIA, etc. that work together with the inspection, repair, and metrology tools and effectively also provide the best possible utilization of the tool capability, capacity and operator resources. In this paper we introduce a new consolidated applications platform called the Reticle Decision Center (RDC) which hosts all these supporting software applications on a centralized server with direct connectivity to mask inspection, repair, metrology tools and more. The paper details how the RDC server is architected to host any application in its native operating system environment and provides for high availability with automatic failover and redundancy. The server along with its host of applications has been tightly integrated with KLA-Tencor's Teron mask inspectors. The paper concludes with showing benefits realized in mask cycle-time and yield as a result of implementing RDC into a high-volume 10nm mask-shop production line.

Electron-beam Induced Processes and their Applicability to Mask Repair

NASA Astrophysics Data System (ADS)

Boegli, Volker A.; Koops, Hans W. P.; Budach, Michael; Edinger, Klaus; Hoinkis, Ottmar; Weyrauch, Bernd; Becker, Rainer; Schmidt, Rudolf; Kaya, Alexander; Reinhardt, Andreas; Braeuer, Stephan; Honold, Heinz; Bihr, Johannes; Greiser, Jens; Eisenmann, Michael

2002-12-01

The applicability of electron-beam induced chemical reactions to mask repair is investigated. To achieve deposition and chemical etching with a focused electron-beam system, it is required to disperse chemicals in a molecular beam to the area of interest with a well-defined amount of molecules and monolayers per second. For repair of opaque defects the precursor gas reacts with the absorber material of the mask and forms a volatile reaction product, which leaves the surface. In this way the surface atoms are removed layer by layer. For clear defect repair, additional material, which is light absorbing in the UV, is deposited onto the defect area. This material is rendered as a nanocrystalline deposit from metal containing precursors. An experimental electron-beam mask repair system is developed and used to perform exploratory work applicable to photo mask, EUV mask, EPL and LEEPL stencil mask repair. The tool is described and specific repair actions are demonstrated. Platinum deposited features with lateral dimensions down to 20 nm demonstrate the high resolution obtainable with electron beam induced processes, while AFM and AIMS measurements indicate, that specifications for mask repair at the 70 nm device node can be met. In addition, examples of etching quartz and TaN are given.

State-of-the-art EUV materials and processes for the 7nm node and beyond

NASA Astrophysics Data System (ADS)

Buitrago, Elizabeth; Meeuwissen, Marieke; Yildirim, Oktay; Custers, Rolf; Hoefnagels, Rik; Rispens, Gijsbert; Vockenhuber, Michaela; Mochi, Iacopo; Fallica, Roberto; Tasdemir, Zuhal; Ekinci, Yasin

2017-03-01

Extreme ultraviolet lithography (EUVL, λ = 13.5 nm) being the most likely candidate to manufacture electronic devices for future technology nodes is to be introduced in high volume manufacturing (HVM) at the 7 nm logic node, at least at critical lithography levels. With this impending introduction, it is clear that excellent resist performance at ultra-high printing resolutions (below 20 nm line/space L/S) is ever more pressing. Nonetheless, EUVL has faced many technical challenges towards this paradigm shift to a new lithography wavelength platform. Since the inception of chemically amplified resists (CARs) they have been the base upon which state-of-the art photoresist technology has been developed from. Resist performance as measured in terms of printing resolution (R), line edge roughness (LER), sensitivity (D or exposure dose) and exposure latitude (EL) needs to be improved but there are well known trade-off relationships (LRS trade-off) among these parameters for CARs that hamper their simultaneous enhancement. Here, we present some of the most promising EUVL materials tested by EUV interference lithography (EUV-IL) with the aim of resolving features down to 11 nm half-pitch (HP), while focusing on resist performance at 16 and 13 nm HP as needed for the 7 and 5 nm node, respectively. EUV-IL has enabled the characterization and development of new resist materials before commercial EUV exposure tools become available and is therefore a powerful research and development tool. With EUV-IL, highresolution periodic images can be printed by the interference of two or more spatially coherent beams through a transmission-diffraction grating mask. For this reason, our experiments have been performed by EUV-IL at Swiss Light Source (SLS) synchrotron facility located at the Paul Scherrer Institute (PSI). Having the opportunity to test hundreds of EUVL materials from vendors and research partners from all over the world, PSI is able to give a global update on some of the most promising materials tested.

Patterning with metal-oxide EUV photoresist: patterning capability, resist smoothing, trimming, and selective stripping

NASA Astrophysics Data System (ADS)

Mao, Ming; Lazzarino, Frederic; De Schepper, Peter; De Simone, Danilo; Piumi, Daniele; Luong, Vinh; Yamashita, Fumiko; Kocsis, Michael; Kumar, Kaushik

2017-03-01

Inpria metal-oxide photoresist (PR) serves as a thin spin-on patternable hard mask for EUV lithography. Compared to traditional organic photoresists, the ultrathin metal-oxide photoresist ( 12nm after development) effectively mitigates pattern collapse. Because of the high etch resistance of the metal-oxide resist, this may open up significant scope for more aggressive etches, new chemistries, and novel integration schemes. We have previously shown that metal-oxide PR can be successfully used to pattern the block layer for the imec 7-nm technology node[1] and advantageously replace a multiple patterning approach, which significantly reduces the process complexity and effectively decreases the cost. We also demonstrated the formation of 16nm half pitch 1:1 line/space with EUV single print[2], which corresponds to a metal 2 layer for the imec 7-nm technology node. In this paper, we investigate the feasibility of using Inpria's metal-oxide PR for 16nm line/space patterning. In meanwhile, we also explore the different etch process for LWR smoothing, resist trimming and resist stripping.

Preliminary results for mask metrology using spatial heterodyne interferometry

NASA Astrophysics Data System (ADS)

Bingham, Philip R.; Tobin, Kenneth; Bennett, Marylyn H.; Marmillion, Pat

2003-12-01

Spatial heterodyne interferometry (SHI) is an imaging technique that captures both the phase and amplitude of a complex wavefront in a single high-speed image. This technology was developed at the Oak Ridge National Laboratory (ORNL) and is currently being implemented for semiconductor wafer inspection by nLine Corporation. As with any system that measures phase, metrology and inspection of surface structures is possible by capturing a wavefront reflected from the surface. The interpretation of surface structure heights for metrology applications can become very difficult with the many layers of various materials used on semiconductor wafers, so inspection (defect detection) has been the primary focus for semiconductor wafers. However, masks used for photolithography typically only contain a couple well-defined materials opening the doors to high-speed mask metrology in 3 dimensions in addition to inspection. Phase shift masks often contain structures etched out of the transparent substrate material for phase shifting. While these structures are difficult to inspect using only intensity, the phase and amplitude images captured with SHI can produce very good resolution of these structures. The phase images also provide depth information that is crucial for these phase shift regions. Preliminary testing has been performed to determine the feasibility of SHI for high-speed non-contact mask metrology using a prototype SHI system with 532 nm wavelength illumination named the Visible Alpha Tool (VAT). These results show that prototype SHI system is capable of performing critical dimension measurements on 400nm lines with a repeatability of 1.4nm and line height measurements with a repeatability of 0.26nm. Additionally initial imaging of an alternating aperture phase shift mask has shown the ability of SHI to discriminate between typical phase shift heights.

Improvement in defect classification efficiency by grouping disposition for reticle inspection

NASA Astrophysics Data System (ADS)

Lai, Rick; Hsu, Luke T. H.; Chang, Peter; Ho, C. H.; Tsai, Frankie; Long, Garrett; Yu, Paul; Miller, John; Hsu, Vincent; Chen, Ellison

2005-11-01

As the lithography design rule of IC manufacturing continues to migrate toward more advanced technology nodes, the mask error enhancement factor (MEEF) increases and necessitates the use of aggressive OPC features. These aggressive OPC features pose challenges to reticle inspection due to high false detection, which is time-consuming for defect classification and impacts the throughput of mask manufacturing. Moreover, higher MEEF leads to stricter mask defect capture criteria so that new generation reticle inspection tool is equipped with better detection capability. Hence, mask process induced defects, which were once undetectable, are now detected and results in the increase of total defect count. Therefore, how to review and characterize reticle defects efficiently is becoming more significant. A new defect review system called ReviewSmart has been developed based on the concept of defect grouping disposition. The review system intelligently bins repeating or similar defects into defect groups and thus allows operators to review massive defects more efficiently. Compared to the conventional defect review method, ReviewSmart not only reduces defect classification time and human judgment error, but also eliminates desensitization that is formerly inevitable. In this study, we attempt to explore the most efficient use of ReviewSmart by evaluating various defect binning conditions. The optimal binning conditions are obtained and have been verified for fidelity qualification through inspection reports (IRs) of production masks. The experiment results help to achieve the best defect classification efficiency when using ReviewSmart in the mask manufacturing and development.

76 FR 9984 - Airworthiness Directives; B/E Aerospace, Continuous Flow Passenger Oxygen Mask Assembly, Part...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-23

..., Continuous Flow Passenger Oxygen Mask Assembly, Part Numbers 174006-(), 174080-(), 174085-(), 174095... manufacturer and part number of the oxygen mask assemblies installed, an inspection to determine the manufacturing date and modification status if certain oxygen mask assemblies are installed, and corrective...

Maskless, reticle-free, lithography

DOEpatents

Ceglio, N.M.; Markle, D.A.

1997-11-25

A lithography system in which the mask or reticle, which usually carries the pattern to be printed onto a substrate, is replaced by a programmable array of binary (i.e. on/off) light valves or switches which can be programmed to replicate a portion of the pattern each time an illuminating light source is flashed. The pattern of light produced by the programmable array is imaged onto a lithographic substrate which is mounted on a scanning stage as is common in optical lithography. The stage motion and the pattern of light displayed by the programmable array are precisely synchronized with the flashing illumination system so that each flash accurately positions the image of the pattern on the substrate. This is achieved by advancing the pattern held in the programmable array by an amount which corresponds to the travel of the substrate stage each time the light source flashes. In this manner the image is built up of multiple flashes and an isolated defect in the array will only have a small effect on the printed pattern. The method includes projection lithographies using radiation other than optical or ultraviolet light. The programmable array of binary switches would be used to control extreme ultraviolet (EUV), x-ray, or electron, illumination systems, obviating the need for stable, defect free masks for projection EUV, x-ray, or electron, lithographies. 7 figs.

Maskless, reticle-free, lithography

DOEpatents

Ceglio, Natale M.; Markle, David A.

1997-11-25

A lithography system in which the mask or reticle, which usually carries the pattern to be printed onto a substrate, is replaced by a programmable array of binary (i.e. on/off) light valves or switches which can be programmed to replicate a portion of the pattern each time an illuminating light source is flashed. The pattern of light produced by the programmable array is imaged onto a lithographic substrate which is mounted on a scanning stage as is common in optical lithography. The stage motion and the pattern of light displayed by the programmable array are precisely synchronized with the flashing illumination system so that each flash accurately positions the image of the pattern on the substrate. This is achieved by advancing the pattern held in the programmable array by an amount which corresponds to the travel of the substrate stage each time the light source flashes. In this manner the image is built up of multiple flashes and an isolated defect in the array will only have a small effect on the printed pattern. The method includes projection lithographies using radiation other than optical or ultraviolet light. The programmable array of binary switches would be used to control extreme ultraviolet (EUV), x-ray, or electron, illumination systems, obviating the need for stable, defect free masks for projection EUV, x-ray, or electron, lithographies.

Inspection of imprint lithography patterns for semiconductor and patterned media

NASA Astrophysics Data System (ADS)

Resnick, Douglas J.; Haase, Gaddi; Singh, Lovejeet; Curran, David; Schmid, Gerard M.; Luo, Kang; Brooks, Cindy; Selinidis, Kosta; Fretwell, John; Sreenivasan, S. V.

2010-03-01

Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Acceptance of imprint lithography for manufacturing will require demonstration that it can attain defect levels commensurate with the requirements of cost-effective device production. This work summarizes the results of defect inspections of semiconductor masks, wafers and hard disks patterned using Jet and Flash Imprint Lithography (J-FILTM). Inspections were performed with optical and e-beam based automated inspection tools. For the semiconductor market, a test mask was designed which included dense features (with half pitches ranging between 32 nm and 48 nm) containing an extensive array of programmed defects. For this work, both e-beam inspection and optical inspection were used to detect both random defects and the programmed defects. Analytical SEMs were then used to review the defects detected by the inspection. Defect trends over the course of many wafers were observed with another test mask using a KLA-T 2132 optical inspection tool. The primary source of defects over 2000 imprints were particle related. For the hard drive market, it is important to understand the defectivity of both the template and the imprinted disk. This work presents a methodology for automated pattern inspection and defect classification for imprint-patterned media. Candela CS20 and 6120 tools from KLA-Tencor map the optical properties of the disk surface, producing highresolution grayscale images of surface reflectivity, scattered light, phase shift, etc. Defects that have been identified in this manner are further characterized according to the morphology

Development of high sensitivity and high speed large size blank inspection system LBIS

NASA Astrophysics Data System (ADS)

Ohara, Shinobu; Yoshida, Akinori; Hirai, Mitsuo; Kato, Takenori; Moriizumi, Koichi; Kusunose, Haruhiko

2017-07-01

The production of high-resolution flat panel displays (FPDs) for mobile phones today requires the use of high-quality large-size photomasks (LSPMs). Organic light emitting diode (OLED) displays use several transistors on each pixel for precise current control and, as such, the mask patterns for OLED displays are denser and finer than the patterns for the previous generation displays throughout the entire mask surface. It is therefore strongly demanded that mask patterns be produced with high fidelity and free of defect. To enable the production of a high quality LSPM in a short lead time, the manufacturers need a high-sensitivity high-speed mask blank inspection system that meets the requirement of advanced LSPMs. Lasertec has developed a large-size blank inspection system called LBIS, which achieves high sensitivity based on a laser-scattering technique. LBIS employs a high power laser as its inspection light source. LBIS's delivery optics, including a scanner and F-Theta scan lens, focus the light from the source linearly on the surface of the blank. Its specially-designed optics collect the light scattered by particles and defects generated during the manufacturing process, such as scratches, on the surface and guide it to photo multiplier tubes (PMTs) with high efficiency. Multiple PMTs are used on LBIS for the stable detection of scattered light, which may be distributed at various angles due to irregular shapes of defects. LBIS captures 0.3mμ PSL at a detection rate of over 99.5% with uniform sensitivity. Its inspection time is 20 minutes for a G8 blank and 35 minutes for G10. The differential interference contrast (DIC) microscope on the inspection head of LBIS captures high-contrast review images after inspection. The images are classified automatically.

Coatings on reflective mask substrates

DOEpatents

Tong, William Man-Wai; Taylor, John S.; Hector, Scott D.; Mangat, Pawitter J. S.; Stivers, Alan R.; Kofron, Patrick G.; Thompson, Matthew A.

2002-01-01

A process for creating a mask substrate involving depositing: 1) a coating on one or both sides of a low thermal expansion material EUVL mask substrate to improve defect inspection, surface finishing, and defect levels; and 2) a high dielectric coating, on the backside to facilitate electrostatic chucking and to correct for any bowing caused by the stress imbalance imparted by either other deposited coatings or the multilayer coating of the mask substrate. An film, such as TaSi, may be deposited on the front side and/or back of the low thermal expansion material before the material coating to balance the stress. The low thermal expansion material with a silicon overlayer and a silicon and/or other conductive underlayer enables improved defect inspection and stress balancing.

Inspection system qualification and integration into the mask manufacturing environment

NASA Astrophysics Data System (ADS)

LaVoy, Rosanne; Fujioka, Ron

1995-12-01

Integration of a mask inspection system into a manufacturing environment poses new challenges to both the inspection engineer and the equipment supplier. Traditional specifications (limited primarily to sensitivity and uptime) are no longer sufficient to successfully integrate a system into a 7 by 24 manufacturing area with multiple systems. Issues such as system sensitivity matching, sensitivity characterization by defect type, operator training and certification standards, and real-time SPC control of the systems must be addressed. This paper outlines some of the techniques Intel Mask Operation uses for integration of a new inspection system into the manufacturing line. Specifically moving a beta- site type tool out of the beta-site mode and into volume production. Examples are presented, including installation for manufacturing (including ergonomic modifications), techniques for system-to-system matching, use of SPC charts to monitor system performance, and operator training/certifications. Relationships between system PMs, or other environmental changes, and the system sensitivity SPC control charts also are discussed.

X-ray mask fabrication advancements at the Microlithographic Mask Development Center

NASA Astrophysics Data System (ADS)

Kimmel, Kurt R.; Hughes, Patrick J.

1996-05-01

The Microlithographic Mask Development Center (MMD) was established as the X-ray mask manufacturing facility at the IBM Microelectronics Division semiconductor fabricator in Essex Junction, Vermont. This center, in operation for over two years, produces high yielding, defect-free X-ray masks for competitive logic and memory products at 250nm groundrules and below. The MMD is a complete mask facility that manufactures silicon membrane mask blanks in the NIST format and finished masks with electroplated gold X-ray absorber. Mask patterning, with dimensions as small as 180 nm, is accomplished using IBM-built variable shaped spot e-beam systems. Masks are routinely inspected and repaired using state-of-the-art equipment: two KLA SEM Specs for defect inspection, a Leica LMS 2000 for image placement characterization, an Amray 2040c for image dimension characterization and a Micrion 8000 XMR for defect repair. This facility maintains a baseline mask process with daily production of 250nm, 32Mb SRAM line monitor masks for the continuous improvement of mask quality and processes. Development masks are produced for several semiconductor manufacturers including IBM, Motorola, Loral, and Sanders. Masks for 64Mb and 256Mb DRAM (IBM) and advanced logic/SRAM (IBM and Motorola) designs have also been delivered. This paper describes the MMD facility and its technical capabilities. Key manufacturing metrics such as mask turnaround time, parametric yield learning and defect reduction activities are highlighted. The challenges associated with improved mask quality, sub-180nm mask fabrication, and the transition to refractory metal absorber are discussed.

A pattern-based method to automate mask inspection files

NASA Astrophysics Data System (ADS)

Kamal Baharin, Ezni Aznida Binti; Muhsain, Mohamad Fahmi Bin; Ahmad Ibrahim, Muhamad Asraf Bin; Ahmad Noorhani, Ahmad Nurul Ihsan Bin; Sweis, Jason; Lai, Ya-Chieh; Hurat, Philippe

2017-03-01

Mask inspection is a critical step in the mask manufacturing process in order to ensure all dimensions printed are within the needed tolerances. This becomes even more challenging as the device nodes shrink and the complexity of the tapeout increases. Thus, the amount of measurement points and their critical dimension (CD) types are increasing to ensure the quality of the mask. In addition to the mask quality, there is a significant amount of manpower needed when the preparation and debugging of this process are not automated. By utilizing a novel pattern search technology with the ability to measure and report match region scan-line (edge) measurements, we can create a flow to find, measure and mark all metrology locations of interest and provide this automated report to the mask shop for inspection. A digital library is created based on the technology product and node which contains the test patterns to be measured. This paper will discuss how these digital libraries will be generated and then utilized. As a time-critical part of the manufacturing process, this can also reduce the data preparation cycle time, minimize the amount of manual/human error in naming and measuring the various locations, reduce the risk of wrong/missing CD locations, and reduce the amount of manpower needed overall. We will also review an example pattern and how the reporting structure to the mask shop can be processed. This entire process can now be fully automated.

Accurate defect die placement and nuisance defect reduction for reticle die-to-die inspections

NASA Astrophysics Data System (ADS)

Wen, Vincent; Huang, L. R.; Lin, C. J.; Tseng, Y. N.; Huang, W. H.; Tuo, Laurent C.; Wylie, Mark; Chen, Ellison; Wang, Elvik; Glasser, Joshua; Kelkar, Amrish; Wu, David

2015-10-01

Die-to-die reticle inspections are among the simplest and most sensitive reticle inspections because of the use of an identical-design neighboring-die for the reference image. However, this inspection mode can have two key disadvantages: (1) The location of the defect is indeterminate because it is unclear to the inspector whether the test or reference image is defective; and (2) nuisance and false defects from mask manufacturing noise and tool optical variation can limit the usable sensitivity. The use of a new sequencing approach for a die-to-die inspection can resolve these issues without any additional scan time, without sacrifice in sensitivity requirement, and with a manageable increase in computation load. In this paper we explore another approach for die-to-die inspections using a new method of defect processing and sequencing. Utilizing die-to-die double arbitration during defect detection has been proven through extensive testing to generate accurate placement of the defect in the correct die to ensure efficient defect disposition at the AIMS step. The use of this method maintained the required inspection sensitivity for mask quality as verified with programmed-defectmask qualification and then further validated with production masks comparing the current inspection approach to the new method. Furthermore, this approach can significantly reduce the total number of defects that need to be reviewed by essentially eliminating the nuisance and false defects that can result from a die-to-die inspection. This "double-win" will significantly reduce the effort in classifying a die-to-die inspection result and will lead to improved cycle times.

Photomask etch system and process for 10nm technology node and beyond

NASA Astrophysics Data System (ADS)

Chandrachood, Madhavi; Grimbergen, Michael; Yu, Keven; Leung, Toi; Tran, Jeffrey; Chen, Jeff; Bivens, Darin; Yalamanchili, Rao; Wistrom, Richard; Faure, Tom; Bartlau, Peter; Crawford, Shaun; Sakamoto, Yoshifumi

2015-10-01

While the industry is making progress to offer EUV lithography schemes to attain ultimate critical dimensions down to 20 nm half pitch, an interim optical lithography solution to address an immediate need for resolution is offered by various integration schemes using advanced PSM (Phase Shift Mask) materials including thin e-beam resist and hard mask. Using the 193nm wavelength to produce 10nm or 7nm patterns requires a range of optimization techniques, including immersion and multiple patterning, which place a heavy demand on photomask technologies. Mask schemes with hard mask certainly help attain better selectivity and hence better resolution but pose integration challenges and defectivity issues. This paper presents a new photomask etch solution for attenuated phase shift masks that offers high selectivity (Cr:Resist > 1.5:1), tighter control on the CD uniformity with a 3sigma value approaching 1 nm and controllable CD bias (5-20 nm) with excellent CD linearity performance (<5 nm) down to the finer resolution. The new system has successfully demonstrated capability to meet the 10 nm node photomask CD requirements without the use of more complicated hard mask phase shift blanks. Significant improvement in post wet clean recovery performance was demonstrated by the use of advanced chamber materials. Examples of CD uniformity, linearity, and minimum feature size, and etch bias performance on 10 nm test site and production mask designs will be shown.

Alternating phase-shifted mask for logic gate levels, design, and mask manufacturing

NASA Astrophysics Data System (ADS)

Liebmann, Lars W.; Graur, Ioana C.; Leipold, William C.; Oberschmidt, James M.; O'Grady, David S.; Regaill, Denis

1999-07-01

While the benefits of alternating phase shifted masks in improving lithographic process windows at increased resolution are well known throughout the lithography community, broad implementation of this potentially powerful technique has been slow due to the inherent complexity of the layout design and mask manufacturing process. This paper will review a project undertaken at IBM's Semiconductor Research and Development Center and Mask Manufacturing and Development facility to understand the technical and logistical issues associated with the application of alternating phase shifted mask technology to the gate level of a full microprocessor chip. The work presented here depicts an important milestone toward integration of alternating phase shifted masks into the manufacturing process by demonstrating an automated design solution and yielding a functional alternating phase shifted mask. The design conversion of the microprocessor gate level to a conjugate twin shifter alternating phase shift layout was accomplished with IBM's internal design system that automatically scaled the design, added required phase regions, and resolved phase conflicts. The subsequent fabrication of a nearly defect free phase shifted mask, as verified by SEM based die to die inspection, highlights the maturity of the alternating phase shifted mask manufacturing process in IBM's internal mask facility. Well defined and recognized challenges in mask inspection and repair remain and the layout of alternating phase shifted masks present a design and data preparation overhead, but the data presented here demonstrate the feasibility of designing and building manufacturing quality alternating phase shifted masks for the gate level of a microprocessor.

Method and apparatus for inspecting reflection masks for defects

DOEpatents

Bokor, Jeffrey; Lin, Yun

2003-04-29

An at-wavelength system for extreme ultraviolet lithography mask blank defect detection is provided. When a focused beam of wavelength 13 nm is incident on a defective region of a mask blank, three possible phenomena can occur. The defect will induce an intensity reduction in the specularly reflected beam, scatter incoming photons into an off-specular direction, and change the amplitude and phase of the electric field at the surface which can be monitored through the change in the photoemission current. The magnitude of these changes will depend on the incident beam size, and the nature, extent and size of the defect. Inspection of the mask blank is performed by scanning the mask blank with 13 nm light focused to a spot a few .mu.m in diameter, while measuring the reflected beam intensity (bright field detection), the scattered beam intensity (dark-field detection) and/or the change in the photoemission current.

Exploration of BEOL line-space patterning options at 12 nm half-pitch and below

NASA Astrophysics Data System (ADS)

Decoster, S.; Lazzarino, F.; Petersen Barbosa Lima, L.; Li, W.; Versluijs, J.; Halder, S.; Mallik, A.; Murdoch, G.

2018-03-01

While the semiconductor industry is almost ready for high-volume manufacturing of the 7 nm technology node, research centers are defining and troubleshooting the patterning options for the 5 nm technology node (N5) and below. The target dimension for imec's N5 BEOL applications is 20-24 nm Metal Pitch (MP), which requires Self-Aligned multiple (Double/Quadruple/Octuple) Patterning approaches (SAxP) in combination with EUV or immersion lithography at 193 nm. There are numerous technical challenges to enable gratings at the hard mask level such as good uniformity across wafer, low line edge/width roughness (LER/LWR), large process window, and all of this at low cost. An even greater challenge is to transfer these gratings into the dielectric material at such critical dimensions, where increased line edge roughness, line wiggling and even pattern collapse can be expected for materials with small mechanical stability such as highly porous low-k dielectrics. In this work we first compare three different patterning options for 12 nm half-pitch gratings at the hard mask level: EUV-based SADP and 193i-based SAQP and SAOP. This comparison will be based on process window, line edge/width roughness and cost. Next, the transfer of 12 nm line/space gratings in the dielectric material is discussed and presented. The LER of the dielectric lines is investigated as a function of the dielectric material, the trench depth, and the stress in the sacrificial hard mask. Finally, we elaborate on the different options to enable scaling down from 24 nm MP to 16 nm MP, and demonstrate 8 nm line/space gratings with 193i-based SAOP.

A novel approach: high resolution inspection with wafer plane defect detection

NASA Astrophysics Data System (ADS)

Hess, Carl; Wihl, Mark; Shi, Rui-fang; Xiong, Yalin; Pang, Song

2008-05-01

High Resolution reticle inspection is well-established as a proven, effective, and efficient means of detecting yield-limiting mask defects as well as defects which are not immediately yield-limiting yet can enable manufacturing process improvements. Historically, RAPID products have enabled detection of both classes of these defects. The newly-developed Wafer Plane Inspection (WPI) detector technology meets the needs of some advanced mask manufacturers to identify the lithographically-significant defects while ignoring the other non-lithographically-significant defects. Wafer Plane Inspection accomplishes this goal by performing defect detection based on a modeled image of how the mask features would actually print in the photoresist. This has the effect of reducing sensitivity to non-printing defects while enabling higher sensitivity focused in high MEEF areas where small reticle defects still yield significant printing defects on wafers. WPI is a new inspection mode that has been developed by KLA-Tencor and is currently under test with multiple customers. It employs the same transmitted and reflected-light high-resolution images as the industry-standard high-resolution inspections, but with much more sophisticated processing involved. A rigorous mask pattern recovery algorithm is used to convert the transmitted and reflected light images into a modeled representation of the reticle. Lithographic modeling of the scanner is then used to generate an aerial image of the mask. This is followed by resist modeling to determine the exposure of the photoresist. The defect detectors are then applied on this photoresist plane so that only printing defects are detected. Note that no hardware modifications to the inspection system are required to enable this detector. The same tool will be able to perform both our standard High Resolution inspections and the Wafer Plane Inspection detector. This approach has several important features. The ability to ignore non-printing defects and to apply additional effective sensitivity in high MEEF areas enables advanced node development. In addition, the modeling allows the inclusion of important polarization effects that occur in the resist for high NA operation. This allows for the results to better match wafer print results compared to alternate approaches. Finally, the simulation easily allows for the application of arbitrary illumination profiles. With this approach, users of WPI can make use of unique or custom scanner illumination profiles. This allows the more precise modeling of profiles without inspection system hardware modification or loss of company intellectual property. This paper examines WPI in Die:Die mode. Future work includes a review of Die:Database WPI capability.

CD control with defect inspection: you can teach an old dog a new trick

NASA Astrophysics Data System (ADS)

Utzny, Clemens; Ullrich, Albrecht; Heumann, Jan; Mohn, Elias; Meusemann, Stefan; Seltmann, Rolf

2012-11-01

Achieving the required critical dimensions (CD) with the best possible uniformity (CDU) on photo-masks has always played a pivotal role in enabling chip technology. Current control strategies are based on scanning electron microscopy (SEM) based measurements implying a sparse spatial resolution on the order of ~ 10-2 m to 10-1 m. A higher spatial resolution could be reached with an adequate measurement sampling, however the increase in the number of measurements makes this approach in the context of a productive environment unfeasible. With the advent of more powerful defect inspection tools a significantly higher spatial resolution of 10-4 m can be achieved by measuring also CD during the regular defect inspection. This method is not limited to the measurement of specific measurement features thus paving the way to a CD assessment of all electrically relevant mask patterns. Enabling such a CD measurement gives way to new realms of CD control. Deterministic short range CD effects which were previously interpreted as noise can be resolved and addressed by CD compensation methods. This in can lead to substantial improvements of the CD uniformity. Thus the defect inspection mediated CD control closes a substantial gap in the mask manufacturing process by allowing the control of short range CD effects which were up till now beyond the reach of regular CD SEM based control strategies. This increase in spatial resolution also counters the decrease in measurement precision due to the usage of an optical system. In this paper we present detailed results on a) the CD data generated during the inspection process, b) the analytical tools needed for relating this data to CD SEM measurement and c) how the CD inspection process enables new dimension of CD compensation within the mask manufacturing process. We find that the inspection based CD measurement generates typically around 500000 measurements with a homogeneous covering of the active mask area. In comparing the CD inspection results with CD SEM measurement on a single measurement point base we find that optical limitations of the inspection tool play a substantial role within the photon based inspection process. Once these shift are characterized and removed a correlation coefficient of 0.9 between these two CD measurement techniques is found. This finding agrees well with a signature based matching approach. Based on these findings we set up a dedicated pooling algorithm which performs on outlier removal for all CD inspections together with a data clustering according to feature specific tool induced shifts. This way tool induced shift effects can be removed and CD signature computation is enabled. A statistical model of the CD signatures which relates the mask design parameters on the relevant length scales to CD effects thus enabling the computation CD compensation maps. The compensation maps address the CD effects on various distinct length scales and we show that long and short range contributions to the CD variation are decreased. We find that the CD uniformity is improved by 25% using this novel CD compensation strategy.

Advances in low-defect multilayers for EUVL mask blanks

NASA Astrophysics Data System (ADS)

Folta, James A.; Davidson, J. Courtney; Larson, Cindy C.; Walton, Christopher C.; Kearney, Patrick A.

2002-07-01

Low-defect multilayer coatings are required to fabricate mask blanks for Extreme Ultraviolet Lithography (EUVL). The mask blanks consist of high reflectance EUV multilayers on low thermal expansion substrates. A defect density of 0.0025 printable defects/cm2 for both the mask substrate and the multilayer is required to provide a mask blank yield of 60 percent. Current low defect multilayer coating technology allows repeated coating-added defect levels of 0.05/cm2 for defects greater than 90 nm polystyrene latex sphere (PSL) equivalent size for lots of 20 substrates. Extended clean operation of the coating system at levels below 0.08/cm2 for 3 months of operation has also been achieved. Two substrates with zero added defects in the quality area have been fabricated, providing an existence proof that ultra low defect coatings are possible. Increasing the ion source-to-target distance from 410 to 560 mm to reduce undesired coating of the ion source caused the defect density to increase to 0.2/cm2. Deposition and etching diagnostic witness substrates and deposition pinhole cameras showed a much higher level of ion beam spillover (ions missing the sputter target) than expected. Future work will quantify beam spillover, and test designs to reduce spillover, if it is confirmed to be the cause of the increased defect level. The LDD system will also be upgraded to allow clean coating of standard format mask substrates. The upgrade will confirm that the low defect process developed on Si wafers is compatible with the standard mask format 152 mm square substrates, and will provide a clean supply of EUVL mask blanks needed to support development of EUVL mask patterning processes and clean mask handling technologies.

The bright-star masks for the HSC-SSP survey

NASA Astrophysics Data System (ADS)

Coupon, Jean; Czakon, Nicole; Bosch, James; Komiyama, Yutaka; Medezinski, Elinor; Miyazaki, Satoshi; Oguri, Masamune

2018-01-01

We present the procedure to build and validate the bright-star masks for the Hyper-Suprime-Cam Strategic Subaru Proposal (HSC-SSP) survey. To identify and mask the saturated stars in the full HSC-SSP footprint, we rely on the Gaia and Tycho-2 star catalogues. We first assemble a pure star catalogue down to GGaia < 18 after removing ˜1.5% of sources that appear extended in the Sloan Digital Sky Survey (SDSS). We perform visual inspection on the early data from the S16A internal release of HSC-SSP, finding that our star catalogue is 99.2% pure down to GGaia < 18. Second, we build the mask regions in an automated way using stacked detected source measurements around bright stars binned per GGaia magnitude. Finally, we validate those masks by visual inspection and comparison with the literature of galaxy number counts and angular two-point correlation functions. This version (Arcturus) supersedes the previous version (Sirius) used in the S16A internal and DR1 public releases. We publicly release the full masks and tools to flag objects in the entire footprint of the planned HSC-SSP observations at "ftp://obsftp.unige.ch/pub/coupon/brightStarMasks/HSC-SSP/".

DOE Office of Scientific and Technical Information (OSTI.GOV)

Claus, Rene A.; Wang, Yow-Gwo; Wojdyla, Antoine

Extreme Ultraviolet (EUV) Lithography mask defects were examined on the actinic mask imaging system, SHARP, at Lawrence Berkeley National Laboratory. Also, a quantitative phase retrieval algorithm based on the Weak Object Transfer Function was applied to the measured through-focus aerial images to examine the amplitude and phase of the defects. The accuracy of the algorithm was demonstrated by comparing the results of measurements using a phase contrast zone plate and a standard zone plate. Using partially coherent illumination to measure frequencies that would otherwise fall outside the numerical aperture (NA), it was shown that some defects are smaller than themore » conventional resolution of the microscope. We found that the programmed defects of various sizes were measured and shown to have both an amplitude and a phase component that the algorithm is able to recover.« less

PMJ panel discussion overview on mask complexities, cost, and cycle time in 32-nm system LSI generation: conflict or concurrent?

NASA Astrophysics Data System (ADS)

Hosono, Kunihiro; Kato, Kokoro

2008-10-01

This is a report on a panel discussion organized in Photomask Japan 2008, where the challenges about "Mask Complexities, Cost, and Cycle Time in 32-nm System LSI Generation" were addressed to have a look over the possible solutions from the standpoints of chipmaker, commercial mask shop, DA tool vendor and equipments makers. The wrap-up is as follows: Mask complexities justify the mask cost, while the acceptable increase rate of 32nm-mask cost significantly differs between mask suppliers or users side. The efficiency progress by new tools or DFM has driven their cycle-time reductions. Mask complexities and cost will be crucial issues prior to cycle time, and there seems to be linear correlation between them. Controlling complexity and cycle time requires developing a mix of advanced technologies, and especially for cost reduction, shot prices in writers and processing rates in inspection tools have been improved remarkably by tool makers. In addition, activities of consortium in Japan (Mask D2I) are expected to enhance the total optimization of mask design, writing and inspection. The cycle-time reduction potentially drives the lowering of mask cost, and, on the other, the pattern complexities and tighter mask specifications get in the way to 32nm generation as well as the nano-economics and market challenges. There are still many difficult problems in mask manufacturing now, and we are sure to go ahead to overcome a 32nm hurdle with the advances of technologies and collaborations by not only technologies but also finance.

A novel approach to mask defect inspection

NASA Astrophysics Data System (ADS)

Sagiv, Amir; Shirman, Yuri; Mangan, Shmoolik

2008-10-01

Memory chips, now constituting a major part of semiconductor market, posit a special challenge for inspection, as they are generally produced with the smallest half-pitch available with today's technology. This is true, in particular, to photomasks of advanced memory devices, which are at the forefront of the "low-k1" regime. In this paper we present a novel photomask inspection approach, that is particularly suitable for low-k1 layers of advanced memory chips, owing to their typical dense and periodic structure. The method we present can produce a very strong signal for small mask defects, by suppression of the modulation of the pattern's image. Unlike dark-field detection, however, here a single diffraction order associated with the pattern generates a constant "gray" background image, that is used for signal enhancement. We define the theoretical basis for the new detection technique, and show, both analytically and numerically, that it can easily achieve a detection line past the printability spec, and that in cases it is at least as sensitive as high-resolution based detection. We also demonstrate this claim experimentally on a customer mask, using the platform of Applied Material's newly released Aera2TM mask inspection tool. The high sensitivity demonstrates the important and often overlooked concept that resolution is not synonymous with sensitivity. The novel detection method is advantageous in several other aspects, such as the very simple implementation, the high throughput, and the relatively simple pre- and post-processing algorithms required for signal extraction. These features, and in particular the very high sensitivity, make this novel detection method an attractive inspection option for advanced memory devices.

Optical inspection system for cylindrical objects

DOEpatents

Brenden, Byron B.; Peters, Timothy J.

1989-01-01

In the inspection of cylindrical objects, particularly O-rings, the object is translated through a field of view and a linear light trace is projected on its surface. An image of the light trace is projected on a mask, which has a size and shape corresponding to the size and shape which the image would have if the surface of the object were perfect. If there is a defect, light will pass the mask and be sensed by a detector positioned behind the mask. Preferably, two masks and associated detectors are used, one mask being convex to pass light when the light trace falls on a projection from the surface and the other concave, to pass light when the light trace falls on a depression in the surface. The light trace may be either dynamic, formed by a scanned laser beam, or static, formed by such a beam focussed by a cylindrical lens. Means are provided to automatically keep the illuminating receiving systems properly aligned.

Automated Visual Inspection Of Integrated Circuits

NASA Astrophysics Data System (ADS)

Noppen, G.; Oosterlinck, Andre J.

1989-07-01

One of the major application fields of image processing techniques is the 'visual inspection'. For a number of rea-sons, the automated visual inspection of Integrated Circuits (IC's) has drawn a lot of attention. : Their very strict design makes them very suitable for an automated inspection. : There is already a lot of experience in the comparable Printed Circuit Board (PCB) and mask inspection. : The mechanical handling of wafers and dice is already an established technology. : Military and medical IC's should be a 100 % failproof. : IC inspection gives a high and allinost immediate payback. In this paper we wil try to give an outline of the problems involved in IC inspection, and the algorithms and methods used to overcome these problems. We will not go into de-tail, but we will try to give a general understanding. Our attention will go to the following topics. : An overview of the inspection process, with an emphasis on the second visual inspection. : The problems encountered in IC inspection, as opposed to the comparable PCB and mask inspection. : The image acquisition devices that can be used to obtain 'inspectable' images. : A general overview of the algorithms that can be used. : A short description of the algorithms developed at the ESAT-MI2 division of the katholieke Universiteit Leuven.

Method to repair localized amplitude defects in a EUV lithography mask blank

DOEpatents

Stearns, Daniel G.; Sweeney, Donald W.; Mirkarimi, Paul B.; Chapman, Henry N.

2005-11-22

A method and apparatus are provided for the repair of an amplitude defect in a multilayer coating. A significant number of layers underneath the amplitude defect are undamaged. The repair technique restores the local reflectivity of the coating by physically removing the defect and leaving a wide, shallow crater that exposes the underlying intact layers. The particle, pit or scratch is first removed the remaining damaged region is etched away without disturbing the intact underlying layers.

Multiple beam mask writers: an industry solution to the write time crisis

NASA Astrophysics Data System (ADS)

Litt, Lloyd C.

2010-09-01

The semiconductor industry is under constant pressure to reduce production costs even as technology complexity increases. Lithography represents the most expensive process due to its high capital equipment costs and the implementation of low-k1 lithographic processes, which has added to the complexity of making masks through the greater use of optical proximity correction, pixelated masks, and double or triple patterning. Each of these mask technologies allows the production of semiconductors at future nodes while extending the utility of current immersion tools. Low k1 patterning complexity combined with increased data due to smaller feature sizes is driving extremely long mask write times. While a majority of the industry is willing to accept mask write times of up to 24 hours, evidence suggests that the write times for many masks at the 22 nm node and beyond will be significantly longer. It has been estimated that $50M+ in non-recurring engineering (NRE) costs will be required to develop a multiple beam mask writer system, yet the business case to recover this kind of investment is not strong. Moreover, funding such a development is a high risk for an individual supplier. The problem is compounded by a disconnect between the tool customer (the mask supplier) and the final mask customer that will bear the increased costs if a high speed writer is not available. Since no individual company will likely risk entering this market, some type of industry-wide funding model will be needed. Because SEMATECH's member companies strongly support a multiple beam technology for mask writers to reduce the write time and cost of 193 nm and EUV masks, SEMATECH plans to pursue an advanced mask writer program in 2011 and 2012. In 2010, efforts will focus on identifying a funding model to address the investment to develop such a technology.

An investigation into scalability and compliance for triple patterning with stitches for metal 1 at the 14nm node

NASA Astrophysics Data System (ADS)

Cork, Christopher; Miloslavsky, Alexander; Friedberg, Paul; Luk-Pat, Gerry

2013-04-01

Lithographers had hoped that single patterning would be enabled at the 20nm node by way of EUV lithography. However, due to delays in EUV readiness, double patterning with 193i lithography is currently relied upon for volume production for the 20nm node's metal 1 layer. At the 14nm and likely at the 10nm node, LE-LE-LE triple patterning technology (TPT) is one of the favored options [1,2] for patterning local interconnect and Metal 1 layers. While previous research has focused on TPT for contact mask, metal layers offer new challenges and opportunities, in particular the ability to decompose design polygons across more than one mask. The extra flexibility offered by the third mask and ability to leverage polygon stitching both serve to improve compliance. However, ensuring TPT compliance - the task of finding a 3-color mask decomposition for a design - is still a difficult task. Moreover, scalability concerns multiply the difficulty of triple patterning decomposition which is an NP-complete problem. Indeed previous work shows that network sizes above a few thousand nodes or polygons start to take significantly longer times to compute [3], making full chip decomposition for arbitrary layouts impractical. In practice Metal 1 layouts can be considered as two separate problem domains, namely: decomposition of standard cells and decomposition of IP blocks. Standard cells typically include only a few 10's of polygons and should be amenable to fast decomposition. Successive design iterations should resolve compliance issues and improve packing density. Density improvements are multiplied repeatedly as standard cells are placed multiple times. IP blocks, on the other hand, may involve very large networks. This paper evaluates multiple approaches to triple patterning decomposition for the Metal 1 layer. The benefits of polygon stitching, in particular, the ability to resolve commonly encountered non-compliant layout configurations and improve packing density, are weighed against the increased difficulty in finding an optimized, legal decomposition and coping with the increased scalability challenges.

Manufacturability study of masks created by inverse lithography technology (ILT)

NASA Astrophysics Data System (ADS)

Martin, Patrick M.; Progler, C. J.; Xiao, G.; Gray, R.; Pang, L.; Liu, Y.

2005-11-01

As photolithography is pushed to fabricate deep-sub wavelength devices for 90nm, 65nm and smaller technology nodes using available exposure tools (i.e., 248nm, 193nm steppers), photomask capability is becoming extremely critical. For example, PSM masks require more complicated processing; aggressive OPC makes the writing time longer and sometimes unpredictable; and, high MEEF imposes much more stringent demands on mask quality. Therefore, in order for any new lithography technology to be adopted into production, mask manufacturability must be studied thoroughly and carefully. In this paper we will present the mask manufacturability study on mask patterns created using Inverse Lithography Technology (ILT). Unlike conventional OPC methodologies, ILT uses a unique outcome-based technology to mathematically determine the mask features that produce the desired on-wafer results. ILT solves the most critical litho challenges of the deep sub-wavelength era. Potential benefits include: higher yield; expanded litho process windows; superb pattern fidelity at 90, 65 & 45-nm nodes; and reduced time-to-silicon - all without changing the existing lithography infrastructure and design-to-silicon flow. In this study a number of cell structures were selected and used as test patterns. "Luminized patterns" were generated for binary mask and attenuated phase-shift mask. Both conventional OPC patterns and "luminized patterns" were put on a test reticle side by side, and they all have a number of variations in term of correction aggressivity level and mask complexity. Mask manufacturability, including data fracturing, writing time, mask inspection, and metrology were studied. The results demonstrate that, by optimizing the inspection recipe, masks created using ILT technology can be made and qualified using current processes with a reasonable turn-around time.

Design strategy for integrating DSA via patterning in sub-7 nm interconnects

NASA Astrophysics Data System (ADS)

Karageorgos, Ioannis; Ryckaert, Julien; Tung, Maryann C.; Wong, H.-S. P.; Gronheid, Roel; Bekaert, Joost; Karageorgos, Evangelos; Croes, Kris; Vandenberghe, Geert; Stucchi, Michele; Dehaene, Wim

2016-03-01

In recent years, major advancements have been made in the directed self-assembly (DSA) of block copolymers (BCPs). As a result, the insertion of DSA for IC fabrication is being actively considered for the sub-7nm nodes. At these nodes the DSA technology could alleviate costs for multiple patterning and limit the number of litho masks that would be required per metal layer. One of the most straightforward approaches for DSA implementation would be for via patterning through templated DSA, where hole patterns are readily accessible through templated confinement of cylindrical phase BCP materials. Our in-house studies show that decomposition of via layers in realistic circuits below the 7nm node would require at least many multi-patterning steps (or colors), using 193nm immersion lithography. Even the use of EUV might require double patterning in these dimensions, since the minimum via distance would be smaller than EUV resolution. The grouping of vias through templated DSA can resolve local conflicts in high density areas. This way, the number of required colors can be significantly reduced. For the implementation of this approach, a DSA-aware mask decomposition is required. In this paper, our design approach for DSA via patterning in sub-7nm nodes is discussed. We propose options to expand the list of DSA-compatible via patterns (DSA letters) and we define matching cost formulas for the optimal DSA-aware layout decomposition. The flowchart of our proposed approach tool is presented.

Simulation based mask defect repair verification and disposition

NASA Astrophysics Data System (ADS)

Guo, Eric; Zhao, Shirley; Zhang, Skin; Qian, Sandy; Cheng, Guojie; Vikram, Abhishek; Li, Ling; Chen, Ye; Hsiang, Chingyun; Zhang, Gary; Su, Bo

2009-10-01

As the industry moves towards sub-65nm technology nodes, the mask inspection, with increased sensitivity and shrinking critical defect size, catches more and more nuisance and false defects. Increased defect counts pose great challenges in the post inspection defect classification and disposition: which defect is real defect, and among the real defects, which defect should be repaired and how to verify the post-repair defects. In this paper, we address the challenges in mask defect verification and disposition, in particular, in post repair defect verification by an efficient methodology, using SEM mask defect images, and optical inspection mask defects images (only for verification of phase and transmission related defects). We will demonstrate the flow using programmed mask defects in sub-65nm technology node design. In total 20 types of defects were designed including defects found in typical real circuit environments with 30 different sizes designed for each type. The SEM image was taken for each programmed defect after the test mask was made. Selected defects were repaired and SEM images from the test mask were taken again. Wafers were printed with the test mask before and after repair as defect printability references. A software tool SMDD-Simulation based Mask Defect Disposition-has been used in this study. The software is used to extract edges from the mask SEM images and convert them into polygons to save in GDSII format. Then, the converted polygons from the SEM images were filled with the correct tone to form mask patterns and were merged back into the original GDSII design file. This merge is for the purpose of contour simulation-since normally the SEM images cover only small area (~1 μm) and accurate simulation requires including larger area of optical proximity effect. With lithography process model, the resist contour of area of interest (AOI-the area surrounding a mask defect) can be simulated. If such complicated model is not available, a simple optical model can be used to get simulated aerial image intensity in the AOI. With built-in contour analysis functions, the SMDD software can easily compare the contour (or intensity) differences between defect pattern and normal pattern. With user provided judging criteria, this software can be easily disposition the defect based on contour comparison. In addition, process sensitivity properties, like MEEF and NILS, can be readily obtained in the AOI with a lithography model, which will make mask defect disposition criteria more intelligent.

Extraction and utilization of the repeating patterns for CP writing in mask making

NASA Astrophysics Data System (ADS)

Shoji, Masahiro; Inoue, Tadao; Yamabe, Masaki

2010-05-01

In May 2006, the Mask Design, Drawing, and Inspection Technology Research Department (Mask D2I) at the Association of Super-Advanced Electronics Technologies (ASET) launched a 4-year program for reducing mask manufacturing cost and TAT by concurrent optimization of Mask Data Preparation (MDP), mask writing, and mask inspection [1]. Figure 1 shows an outline of the project at Mask D2I at ASET. As one of the tasks being pursued at the Mask Design Data Technology Research Laboratory we have evaluated the effect of reducing the writing shot counts by utilizing the repeating patterns, and that showed positive impact on mask making by using CP writing. During the past four years, we have developed a software to extract repeating patterns from fractured OPCed mask data and have evaluated the efficiency of reducing the writing shot counts using the repeating patterns with this software. In this evaluation, we have used many actual device production data obtained from the member companies of Mask D2I. To the extraction software, we added new functions for extracting common repeating patterns from a set of multiple masks, and studied how this step affects the ratio of reducing the shot counts in comparison to the case of utilization of the repeating patterns for single mask. We have also developed a software that uses the result of extracting repeating patterns and prepares writing-data for the MCC/CP writing system which has been developed at the Mask Writing Equipment Technology Research Laboratory. With this software, we have examined how EB proximity effect on CP writing affects in reducing the shot count where CP shots with large CD errors have to be divided into VSB shots. In this paper we will report on making common CP mask from a set of multiple actual device data by using these software, and will also report on the results of CP writing and calculation of writing-TAT by MCC/CP writing system.

SL2+: H5 use case

NASA Astrophysics Data System (ADS)

Ito, Kosuke; Liu, Steven; Lee, Isaac; Dover, Russell; Yu, Paul

2008-10-01

Photomask contamination inspections, whether performed at maskshops as an outgoing inspection or at wafer fabs for incoming shipping and handling or progressive defect monitoring, have been performed by KLA-Tencor STARlight systems for a number of design nodes. STARlight has evolved since it first appeared on the 3xx generation of KLA-Tencor mask inspection tools. It was improved with the TeraStar (also known as SLF) based tools with the SL1 algorithm. SL2 first appeared on the TeraScan systems (also known as 5xx) and has been widely adopted in both mask shops and wafer fabs. Design rules continue to advance as do inspection challenges. Advances in computer processing power have enabled more complex and powerful algorithms to be developed and applied to the STARlight technology. The current generation of STARlight, which is known as SL2+, implements improved modeling fidelity as well as a completely new paradigm to the existing STARlight technology known as HiRes5, or simply "H5". H5 is integrated seamlessly within SL2+ and provides die-to-die-like performance in both transmitted and reflected light, in addition to the STARlight detection, in unit time. It achieves this by automatically identifying repeating structures in both X and Y directions and applying image alignment and difference threshold. A leading mask shop partnered with KLA-Tencor in order to evaluate SL2+ at its facility. SL2+ demonstrated a high level of sensitivity on all test reticles, with good inspectability on advanced production reticles. High sensitivity settings were used for 45 nm HP and smaller design rule masks and low false detections were achieved. H5 provided additional sensitivity on production plates, demonstrating the ability to extend the use of SL2+ to cover 32 nm DR plate inspections. This paper reports the findings and results of this evaluation.

A study of phase defect measurement on EUV mask by multiple detectors CD-SEM

NASA Astrophysics Data System (ADS)

Yonekura, Isao; Hakii, Hidemitsu; Morisaki, Shinya; Murakawa, Tsutomu; Shida, Soichi; Kuribara, Masayuki; Iwai, Toshimichi; Matsumoto, Jun; Nakamura, Takayuki

2013-06-01

We have studied MVM (Multi Vision Metrology) -SEM® E3630 to measure 3D shape of defects. The four detectors (Detector A, B, C and D) are independently set up in symmetry for the primary electron beam axis. Signal processing of four direction images enables not only 2D (width) measurement but also 3D (height) measurement. At last PMJ, we have investigated the relation between the E3630's signal of programmed defect on MoSi-HT and defect height measured by AFM (Atomic Force Microscope). It was confirmed that height of integral profile by this tool is correlated with AFM. It was tested that E3630 has capability of observing multilayer defect on EUV. We have investigated correlation with AFM of width and depth or height of multilayer defect. As the result of observing programmed defects, it was confirmed that measurement result by E3630 is well correlated with AFM. And the function of 3D view image enables to show nm order defect.

New method of 2-dimensional metrology using mask contouring

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Yamagata, Yoshikazu; Sugiyama, Akiyuki; Toyoda, Yasutaka

2008-10-01

We have developed a new method of accurately profiling and measuring of a mask shape by utilizing a Mask CD-SEM. The method is intended to realize high accuracy, stability and reproducibility of the Mask CD-SEM adopting an edge detection algorithm as the key technology used in CD-SEM for high accuracy CD measurement. In comparison with a conventional image processing method for contour profiling, this edge detection method is possible to create the profiles with much higher accuracy which is comparable with CD-SEM for semiconductor device CD measurement. This method realizes two-dimensional metrology for refined pattern that had been difficult to measure conventionally by utilizing high precision contour profile. In this report, we will introduce the algorithm in general, the experimental results and the application in practice. As shrinkage of design rule for semiconductor device has further advanced, an aggressive OPC (Optical Proximity Correction) is indispensable in RET (Resolution Enhancement Technology). From the view point of DFM (Design for Manufacturability), a dramatic increase of data processing cost for advanced MDP (Mask Data Preparation) for instance and surge of mask making cost have become a big concern to the device manufacturers. This is to say, demands for quality is becoming strenuous because of enormous quantity of data growth with increasing of refined pattern on photo mask manufacture. In the result, massive amount of simulated error occurs on mask inspection that causes lengthening of mask production and inspection period, cost increasing, and long delivery time. In a sense, it is a trade-off between the high accuracy RET and the mask production cost, while it gives a significant impact on the semiconductor market centered around the mask business. To cope with the problem, we propose the best method of a DFM solution using two-dimensional metrology for refined pattern.

Optimal mask characterization by Surrogate Wafer Print (SWaP) method

NASA Astrophysics Data System (ADS)

Kimmel, Kurt R.; Hoellein, Ingo; Peters, Jan Hendrick; Ackmann, Paul; Connolly, Brid; West, Craig

2008-10-01

Traditionally, definition of mask specifications is done completely by the mask user, while characterization of the mask relative to the specifications is done completely by the mask maker. As the challenges of low-k1 imaging continue to grow in scope of designs and in absolute complexity, the inevitable partnership between wafer lithographers and mask makers has strengthened as well. This is reflected in the jointly owned mask facilities and device manufacturers' continued maintenance of fully captive mask shops which foster the closer mask-litho relationships. However, while some device manufacturers have leveraged this to optimize mask specifications before the mask is built and, therefore, improve mask yield and cost, the opportunity for post-fabrication partnering on mask characterization is more apparent and compelling. The Advanced Mask Technology Center (AMTC) has been investigating the concept of assessing how a mask images, rather than the mask's physical attributes, as a technically superior and lower-cost method to characterize a mask. The idea of printing a mask under its intended imaging conditions, then characterizing the imaged wafer as a surrogate for traditional mask inspections and measurements represents the ultimate method to characterize a mask's performance, which is most meaningful to the user. Surrogate wafer print (SWaP) is already done as part of leading-edge wafer fab mask qualification to validate defect and dimensional performance. In the past, the prospect of executing this concept has generally been summarily discarded as technically untenable and logistically intractable. The AMTC published a paper at BACUS 2007 successfully demonstrating the performance of SWaP for the characterization of defects as an alternative to traditional mask inspection [1]. It showed that this concept is not only feasible, but, in some cases, desirable. This paper expands on last year's work at AMTC to assess the full implementation of SWaP as an enhancement to mask characterization quality including defectivity, dimensional control, pattern fidelity, and in-plane distortion. We present a thorough analysis of both the technical and logistical challenges coupled with an objective view of the advantages and disadvantages from both the technical and financial perspectives. The analysis and model used by the AMTC will serve to provoke other mask shops to prepare their own analyses then consider this new paradigm for mask characterization and qualification.

Small Coronal Holes Near Active Regions as Sources of Slow Solar Wind

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Y.-M., E-mail: yi.wang@nrl.navy.mil

We discuss the nature of the small areas of rapidly diverging, open magnetic flux that form in the strong unipolar fields at the peripheries of active regions (ARs), according to coronal extrapolations of photospheric field measurements. Because such regions usually have dark counterparts in extreme-ultraviolet (EUV) images, we refer to them as coronal holes, even when they appear as narrow lanes or contain sunspots. Revisiting previously identified “AR sources” of slow solar wind from 1998 and 1999, we find that they are all associated with EUV coronal holes; the absence of well-defined He i 1083.0 nm counterparts to some ofmore » these holes is attributed to the large flux of photoionizing radiation from neighboring AR loops. Examining a number of AR-associated EUV holes during the 2014 activity maximum, we confirm that they are characterized by wind speeds of ∼300–450 km s{sup −1}, O{sup 7+}/O{sup 6+} ratios of ∼0.05–0.4, and footpoint field strengths typically of order 30 G. The close spacing between ARs at sunspot maximum limits the widths of unipolar regions and their embedded holes, while the continual emergence of new flux leads to rapid changes in the hole boundaries. Because of the highly nonradial nature of AR fields, the smaller EUV holes are often masked by the overlying canopy of loops, and may be more visible toward one solar limb than at central meridian. As sunspot activity declines, the AR remnants merge to form much larger, weaker, and longer-lived unipolar regions, which harbor the “classical” coronal holes that produce recurrent high-speed streams.« less

EUV focus sensor: design and modeling

NASA Astrophysics Data System (ADS)

Goldberg, Kenneth A.; Teyssier, Maureen E.; Liddle, J. Alexander

2005-05-01

We describe performance modeling and design optimization of a prototype EUV focus sensor (FS) designed for use with existing 0.3-NA EUV projection-lithography tools. At 0.3-NA and 13.5-nm wavelength, the depth of focus shrinks to 150 nm increasing the importance of high-sensitivity focal-plane detection tools. The FS is a free-standing Ni grating structure that works in concert with a simple mask pattern of regular lines and spaces at constant pitch. The FS pitch matches that of the image-plane aerial-image intensity: it transmits the light with high efficiency when the grating is aligned with the aerial image laterally and longitudinally. Using a single-element photodetector, to detect the transmitted flux, the FS is scanned laterally and longitudinally so the plane of peak aerial-image contrast can be found. The design under consideration has a fixed image-plane pitch of 80-nm, with aperture widths of 12-40-nm (1-3 wave-lengths), and aspect ratios of 2-8. TEMPEST-3D is used to model the light transmission. Careful attention is paid to the annular, partially coherent, unpolarized illumination and to the annular pupil of the Micro-Exposure Tool (MET) optics for which the FS is designed. The system design balances the opposing needs of high sensitivity and high throughput opti-mizing the signal-to-noise ratio in the measured intensity contrast.

EUV Focus Sensor: Design and Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberg, Kenneth A.; Teyssier, Maureen E.; Liddle, J. Alexander

We describe performance modeling and design optimization of a prototype EUV focus sensor (FS) designed for use with existing 0.3-NA EUV projection-lithography tools. At 0.3-NA and 13.5-nm wavelength, the depth of focus shrinks to 150 nm increasing the importance of high-sensitivity focal-plane detection tools. The FS is a free-standing Ni grating structure that works in concert with a simple mask pattern of regular lines and spaces at constant pitch. The FS pitch matches that of the image-plane aerial-image intensity: it transmits the light with high efficiency when the grating is aligned with the aerial image laterally and longitudinally. Using amore » single-element photodetector, to detect the transmitted flux, the FS is scanned laterally and longitudinally so the plane of peak aerial-image contrast can be found. The design under consideration has a fixed image-plane pitch of 80-nm, with aperture widths of 12-40-nm (1-3 wavelengths), and aspect ratios of 2-8. TEMPEST-3D is used to model the light transmission. Careful attention is paid to the annular, partially coherent, unpolarized illumination and to the annular pupil of the Micro-Exposure Tool (MET) optics for which the FS is designed. The system design balances the opposing needs of high sensitivity and high throughput optimizing the signal-to-noise ratio in the measured intensity contrast.« less

Mask manufacturing improvement through capability definition and bottleneck line management

NASA Astrophysics Data System (ADS)

Strott, Al

1994-02-01

In 1989, Intel's internal mask operation limited itself to research and development activities and re-inspection and pellicle application of externally manufactured masks. Recognizing the rising capital cost of mask manufacturing at the leading edge, Intel's Mask Operation management decided to offset some of these costs by manufacturing more masks internally. This was the beginning of the challenge they set to manufacture at least 50% of Intel's mask volume internally, at world class performance levels. The first step in responding to this challenge was the completion of a comprehensive operation capability analysis. A series of bottleneck improvements by focus teams resulted in an average cycle time improvement to less than five days on all product and less than two days on critical products.

The anisotropy of 3D shock evolution and its connection to the longitudinal distribution of SEP properties

NASA Astrophysics Data System (ADS)

Feng, L.; Inhester, B.; Wei, Y.; Guo, J.; Plowman, J.; West, M. J.

2016-12-01

We Follow the 3D evolution of a coronal shock from its birth in the AIA field of view (FOV) to its propagation in interplanetary space till Mars. The shock structure is identified using the center-median filtering method which is applied to EUV observations including SDO/AIA and Proba2/SWAP. Then 3D shock morphology is reconstructed with the mask-fitting method (Feng et al. 2012,2013) from the triple-view observations at Earth, STEREO A and B in the FOV from EUV through coronagraph to heliospheric images. The mask-fitting method allows us to obtain a better shape of the 3D shock and calculate the anisotropy of shock evolution. The shock signals were later recorded in in-situ data by Messenger (0.39 AU), Venus Express (0.72 AU), WIND/ACE (1AU), STEREO B (1.03AU), Mars Science Laboratory (1.20AU), and Mars Express(1.52AU). These spacecraft were located at different distances and different longitudes relative to the Sun. Therefore, the corresponding in-situ data can provide further constraint on the shock dynamics along different directions on one hand, on the other hand reveal longitudinal distributions of SEPs in a wide angle of about 120 degrees. We also run ENLIL simulations based on the derived 3D shock morphology and dynamics. The magnetic field connectivity to aforementioned spacecraft and the obtained shock characteristics (e.g., shock geometry, speed, Alfven Mach number, etc.) at cobpoint can help with the understanding of the SEP properties (e.g., energy spectra) measured at different longitudes.

A methodology for cloud masking uncalibrated lidar signals

NASA Astrophysics Data System (ADS)

Binietoglou, Ioannis; D'Amico, Giuseppe; Baars, Holger; Belegante, Livio; Marinou, Eleni

2018-04-01

Most lidar processing algorithms, such as those included in EARLINET's Single Calculus Chain, can be applied only to cloud-free atmospheric scenes. In this paper, we present a methodology for masking clouds in uncalibrated lidar signals. First, we construct a reference dataset based on manual inspection and then train a classifier to separate clouds and cloud-free regions. Here we present details of this approach together with an example cloud masks from an EARLINET station.

Shuttle Wing Leading Edge Root Cause NDE Team Findings and Implementation of Quantitative Flash Infrared Thermography

NASA Technical Reports Server (NTRS)

Burke, Eric R.

2009-01-01

Comparison metrics can be established to reliably and repeatedly establish the health of the joggle region of the Orbiter Wing Leading Edge reinforced carbon carbon (RCC) panels. Using these metrics can greatly reduced the man hours needed to perform, wing leading edge scanning for service induced damage. These time savings have allowed for more thorough inspections to be preformed in the necessary areas with out affecting orbiter flow schedule. Using specialized local inspections allows for a larger margin of safety by allowing for more complete characterizations of panel defects. The presence of the t-seal during thermographic inspection can have adverse masking affects on ability properly characterize defects that exist in the joggle region of the RCC panels. This masking affect dictates the final specialized inspection should be preformed with the t-seal removed. Removal of the t-seal and use of the higher magnification optics has lead to the most effective and repeatable inspection method for characterizing and tracking defects in the wing leading edge. Through this study some inadequacies in the main health monitoring system for the orbiter wing leading edge have been identified and corrected. The use of metrics and local specialized inspection have lead to a greatly increased reliability and repeatable inspection of the shuttle wing leading edge.

Design intent optimization at the beyond 7nm node: the intersection of DTCO and EUVL stochastic mitigation techniques

NASA Astrophysics Data System (ADS)

Crouse, Michael; Liebmann, Lars; Plachecki, Vince; Salama, Mohamed; Chen, Yulu; Saulnier, Nicole; Dunn, Derren; Matthew, Itty; Hsu, Stephen; Gronlund, Keith; Goodwin, Francis

2017-03-01

The initial readiness of EUV patterning was demonstrated in 2016 with IBM Alliance's 7nm device technology. The focus has now shifted to driving the 'effective' k1 factor and enabling the second generation of EUV patterning. Thus, Design Technology Co-optimization (DTCO) has become a critical part of technology enablement as scaling has become more challenging and the industry pushes the limits of EUV lithography. The working partnership between the design teams and the process development teams typically involves an iterative approach to evaluate the manufacturability of proposed designs, subsequent modifications to those designs and finally a design manual for the technology. While this approach has served the industry well for many generations, the challenges at the Beyond 7nm node require a more efficient approach. In this work, we describe the use of "Design Intent" lithographic layout optimization where we remove the iterative component of DTCO and replace it with an optimization that achieves both a "patterning friendly" design and minimizes the well-known EUV stochastic effects. Solved together, this "design intent" approach can more quickly achieve superior lithographic results while still meeting the original device's functional specifications. Specifically, in this work we will demonstrate "design intent" optimization for critical BEOL layers using design tolerance bands to guide the source mask co-optimization. The design tolerance bands can be either supplied as part of the original design or derived from some basic rules. Additionally, the EUV stochastic behavior is mitigated by enhancing the image log slope (ILS) for specific key features as part of the overall optimization. We will show the benefit of the "design intent approach" on both bidirectional and unidirectional 28nm min pitch standard logic layouts and compare the more typical iterative SMO approach. Thus demonstrating the benefit of allowing the design to float within the specified range. Lastly, we discuss how the evolution of this approach could lead to layout optimization based entirely on some minimal set of functional requirements and process constraints.

Apollo-Soyuz survey of the extreme-ultraviolet/soft X-ray background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stern, R.; Bowyer, S.

1979-06-15

The results of an extensive sky survey of the extreme-ultraviolet (EUV)/soft X-ray background are reported. The data were obtained with a telescope, designed and calibrated at the University of California at Berkeley, which observed EUV sources and the diffuse background as part of the Apollo-Soyuz mission in 1975 July. With a primary field of view of 2 /sup 0/.3 +- 0 /sup 0/.1 FWHM and four EUV bandpass filters (16--25, 20--73, 80--108, and 80--250 eV), the EUV telescope obtained useful background data for 21 sky points, 11 large angle scans, and an additional group of short observations of both types.more » Analysis of the data reveals an intense 80--108 eV diffuse flux of 4.0 +- 1.3 photons cm/sup -2/ sr/sup -1/ eV/sup -1/ (broad-band weighted average). This is roughly a factor of 10 higher than the corresponding 150--280 eV average intensity and confirms the earlier results of Cash, Malina, and Stern. Galactic contributions to the background intensity at still lower energies are most likely masked by large fluxes of geocoronal or interplanetary solar-scattered resonance radiation; however, we drive upper limits to the local galactic background of 2 x 10/sup 4/ and 6 x 10/sup 2/ photons cm/sup -2/ sr/sup -1/ eV/sup -1/ averaged over the 16--25 eV and 20--73 eV bands, respectively. The uniformity of the background flux is uncertain due to limitations in the statistical accuracy of the data; we discuss probable upper limits to any spatial anisotropy. No evidence is found for a correlation between the telescope count rate and Earth-based parameters (zenith angle, Sun angle, etc.) for E> or approx. =80 eV. Unlike some previous claims for the soft X-ray background, no simple dependence upon galactic latitude is seen.Fitting models of thermal emission to the Apollo-Soyuz data yields constraints on model parameters that are consistent for a limited range of temperatures with the EUV results of Cash, Malina, and Stern and the soft X-ray data of Burstein et al.« less

Massively parallel E-beam inspection: enabling next-generation patterned defect inspection for wafer and mask manufacturing

NASA Astrophysics Data System (ADS)

Malloy, Matt; Thiel, Brad; Bunday, Benjamin D.; Wurm, Stefan; Mukhtar, Maseeh; Quoi, Kathy; Kemen, Thomas; Zeidler, Dirk; Eberle, Anna Lena; Garbowski, Tomasz; Dellemann, Gregor; Peters, Jan Hendrik

2015-03-01

SEMATECH aims to identify and enable disruptive technologies to meet the ever-increasing demands of semiconductor high volume manufacturing (HVM). As such, a program was initiated in 2012 focused on high-speed e-beam defect inspection as a complement, and eventual successor, to bright field optical patterned defect inspection [1]. The primary goal is to enable a new technology to overcome the key gaps that are limiting modern day inspection in the fab; primarily, throughput and sensitivity to detect ultra-small critical defects. The program specifically targets revolutionary solutions based on massively parallel e-beam technologies, as opposed to incremental improvements to existing e-beam and optical inspection platforms. Wafer inspection is the primary target, but attention is also being paid to next generation mask inspection. During the first phase of the multi-year program multiple technologies were reviewed, a down-selection was made to the top candidates, and evaluations began on proof of concept systems. A champion technology has been selected and as of late 2014 the program has begun to move into the core technology maturation phase in order to enable eventual commercialization of an HVM system. Performance data from early proof of concept systems will be shown along with roadmaps to achieving HVM performance. SEMATECH's vision for moving from early-stage development to commercialization will be shown, including plans for development with industry leading technology providers.

Extended surface parallel coating inspection method

DOEpatents

Naulleau, Patrick P.

2006-03-21

Techniques for rapidly characterizing reflective surfaces and especially multi-layer EUV reflective surfaces of optical components involve illuminating the entire reflective surface instantaneously and detecting the image far field. The technique provides a mapping of points on the reflective surface to corresponding points on a detector, e.g., CCD. This obviates the need to scan a probe over the entire surface of the optical component. The reflective surface can be flat, convex, or concave.

EUV patterning using CAR or MOX photoresist at low dose exposure for sub 36nm pitch

NASA Astrophysics Data System (ADS)

Thibaut, Sophie; Raley, Angélique; Lazarrino, Frederic; Mao, Ming; De Simone, Danilo; Piumi, Daniele; Barla, Kathy; Ko, Akiteru; Metz, Andrew; Kumar, Kaushik; Biolsi, Peter

2018-04-01

The semiconductor industry has been pushing the limits of scalability by combining 193nm immersion lithography with multi-patterning techniques for several years. Those integrations have been declined in a wide variety of options to lower their cost but retain their inherent variability and process complexity. EUV lithography offers a much desired path that allows for direct print of line and space at 36nm pitch and below and effectively addresses issues like cycle time, intra-level overlay and mask count costs associated with multi-patterning. However it also brings its own sets of challenges. One of the major barrier to high volume manufacturing implementation has been hitting the 250W power exposure required for adequate throughput [1]. Enabling patterning using a lower dose resist could help move us closer to the HVM throughput targets assuming required performance for roughness and pattern transfer can be met. As plasma etching is known to reduce line edge roughness on 193nm lithography printed features [2], we investigate in this paper the level of roughness that can be achieved on EUV photoresist exposed at a lower dose through etch process optimization into a typical back end of line film stack. We will study 16nm lines printed at 32 and 34nm pitch. MOX and CAR photoresist performance will be compared. We will review step by step etch chemistry development to reach adequate selectivity and roughness reduction to successfully pattern the target layer.

Ruthenium (Ru) peeling and predicting robustness of the capping layer using finite element method (FEM) modeling

NASA Astrophysics Data System (ADS)

Jang, Il-Yong; John, Arun; Goodwin, Frank; Lee, Su-Young; Kim, Byung-Gook; Kim, Seong-Sue; Jeon, Chan-Uk; Kim, Jae Hyung; Jang, Yong Hoon

2014-07-01

Ruthenium (Ru) film used as capping layer in extreme ultraviolet (EUV) mask peeled off after annealing and in-situ UV (IUV) cleaning. We investigated Ru peeling and found out that the mechanical stress caused by the formation of Si oxide due to the penetration of oxygen atoms from ambient or cleaning media to top-Si of ML is the root cause for the problem. To support our experimental results, we developed a numerical model of finite element method (FEM) using commercial software (ABAQUS™) to calculate the stress and displacement forced on the capping layer. By using this model, we could observe that the displacement agrees well with the actual results measured from the transmission electron microscopy (TEM) image. Using the ion beam deposition (IBD) tool at SEMATECH, we developed four new types of alternative capping materials (RuA, RuB, B4C, B4C-buffered Ru). The durability of each new alternative capping layer observed by experiment was better than that of conventional Ru. The stress and displacement calculated from each new alternative capping layer, using modeling, also agreed well with the experimental results. A new EUV mask structure is proposed, inserting a layer of B4C (B4C-buffered Ru) at the interface between the capping layer (Ru) and the top-Si layer. The modeling results showed that the maximum displacement and bending stress observed from the B4C-buffered Ru are significantly lower than that of single capping layer cases. The durability investigated from the experiment also showed that the B4C-buffered structure is at least 3X stronger than that of conventional Ru.

Enhanced capture rate for haze defects in production wafer inspection

NASA Astrophysics Data System (ADS)

Auerbach, Ditza; Shulman, Adi; Rozentsvige, Moshe

2010-03-01

Photomask degradation via haze defect formation is an increasing troublesome yield problem in the semiconductor fab. Wafer inspection is often utilized to detect haze defects due to the fact that it can be a bi-product of process control wafer inspection; furthermore, the detection of the haze on the wafer is effectively enhanced due to the multitude of distinct fields being scanned. In this paper, we demonstrate a novel application for enhancing the wafer inspection tool's sensitivity to haze defects even further. In particular, we present results of bright field wafer inspection using the on several photo layers suffering from haze defects. One way in which the enhanced sensitivity can be achieved in inspection tools is by using a double scan of the wafer: one regular scan with the normal recipe and another high sensitivity scan from which only the repeater defects are extracted (the non-repeater defects consist largely of noise which is difficult to filter). Our solution essentially combines the double scan into a single high sensitivity scan whose processing is carried out along two parallel routes (see Fig. 1). Along one route, potential defects follow the standard recipe thresholds to produce a defect map at the nominal sensitivity. Along the alternate route, potential defects are used to extract only field repeater defects which are identified using an optimal repeater algorithm that eliminates "false repeaters". At the end of the scan, the two defect maps are merged into one with optical scan images available for all the merged defects. It is important to note, that there is no throughput hit; in addition, the repeater sensitivity is increased relative to a double scan, due to a novel runtime algorithm implementation whose memory requirements are minimized, thus enabling to search a much larger number of potential defects for repeaters. We evaluated the new application on photo wafers which consisted of both random and haze defects. The evaluation procedure involved scanning with three different recipe types: Standard Inspection: Nominal recipe with a low false alarm rate was used to scan the wafer and repeaters were extracted from the final defect map. Haze Monitoring Application: Recipe sensitivity was enhanced and run on a single field column from which on repeating defects were extracted. Enhanced Repeater Extractor: Defect processing included the two parallel routes: a nominal recipe for the random defects and the new high sensitive repeater extractor algorithm. The results showed that the new application (recipe #3) had the highest capture rate on haze defects and detected new repeater defects not found in the first two recipes. In addition, the recipe was much simpler to setup since repeaters are filtered separately from random defects. We expect that in the future, with the advent of mask-less lithography and EUV lithography, the monitoring of field and die repeating defects on the wafer will become a necessity for process control in the semiconductor fab.

Increasing reticle inspection efficiency and reducing wafer print-checks using automated defect classification and simulation

NASA Astrophysics Data System (ADS)

Ryu, Sung Jae; Lim, Sung Taek; Vacca, Anthony; Fiekowsky, Peter; Fiekowsky, Dan

2013-09-01

IC fabs inspect critical masks on a regular basis to ensure high wafer yields. These requalification inspections are costly for many reasons including the capital equipment, system maintenance, and labor costs. In addition, masks typically remain in the "requal" phase for extended, non-productive periods of time. The overall "requal" cycle time in which reticles remain non-productive is challenging to control. Shipping schedules can slip when wafer lots are put on hold until the master critical layer reticle is returned to production. Unfortunately, substituting backup critical layer reticles can significantly reduce an otherwise tightly controlled process window adversely affecting wafer yields. One major requal cycle time component is the disposition process of mask inspections containing hundreds of defects. Not only is precious non-productive time extended by reviewing hundreds of potentially yield-limiting detections, each additional classification increases the risk of manual review techniques accidentally passing real yield limiting defects. Even assuming all defects of interest are flagged by operators, how can any person's judgment be confident regarding lithographic impact of such defects? The time reticles spend away from scanners combined with potential yield loss due to lithographic uncertainty presents significant cycle time loss and increased production costs. Fortunately, a software program has been developed which automates defect classification with simulated printability measurement greatly reducing requal cycle time and improving overall disposition accuracy. This product, called ADAS (Auto Defect Analysis System), has been tested in both engineering and high-volume production environments with very successful results. In this paper, data is presented supporting significant reduction for costly wafer print checks, improved inspection area productivity, and minimized risk of misclassified yield limiting defects.

Comparison of binary mask defect printability analysis using virtual stepper system and aerial image microscope system

NASA Astrophysics Data System (ADS)

Phan, Khoi A.; Spence, Chris A.; Dakshina-Murthy, S.; Bala, Vidya; Williams, Alvina M.; Strener, Steve; Eandi, Richard D.; Li, Junling; Karklin, Linard

1999-12-01

As advanced process technologies in the wafer fabs push the patterning processes toward lower k1 factor for sub-wavelength resolution printing, reticles are required to use optical proximity correction (OPC) and phase-shifted mask (PSM) for resolution enhancement. For OPC/PSM mask technology, defect printability is one of the major concerns. Current reticle inspection tools available on the market sometimes are not capable of consistently differentiating between an OPC feature and a true random defect. Due to the process complexity and high cost associated with the making of OPC/PSM reticles, it is important for both mask shops and lithography engineers to understand the impact of different defect types and sizes to the printability. Aerial Image Measurement System (AIMS) has been used in the mask shops for a number of years for reticle applications such as aerial image simulation and transmission measurement of repaired defects. The Virtual Stepper System (VSS) provides an alternative method to do defect printability simulation and analysis using reticle images captured by an optical inspection or review system. In this paper, pre- programmed defects and repairs from a Defect Sensitivity Monitor (DSM) reticle with 200 nm minimum features (at 1x) will be studied for printability. The simulated resist lines by AIMS and VSS are both compared to SEM images of resist wafers qualitatively and quantitatively using CD verification.Process window comparison between unrepaired and repaired defects for both good and bad repair cases will be shown. The effect of mask repairs to resist pattern images for the binary mask case will be discussed. AIMS simulation was done at the International Sematech, Virtual stepper simulation at Zygo and resist wafers were processed at AMD-Submicron Development Center using a DUV lithographic process for 0.18 micrometer Logic process technology.

Status and path to a final EUVL reticle-handling solution

NASA Astrophysics Data System (ADS)

He, Long; Orvek, Kevin; Seidel, Phil; Wurm, Stefan; Underwood, Jon; Betancourt, Ernie

2007-03-01

In extreme ultraviolet lithography (EUVL), the lack of a suitable material to build conventional pellicles calls for industry standardization of new techniques for protection and handling throughout the reticle's lifetime. This includes reticle shipping, robotic handling, in-fab transport, storage, and uses in atmospheric environments for metrology and vacuum environments for EUV exposure. In this paper, we review the status of the industry-wide progress in developing EUVL reticle-handling solutions. We show the industry's leading reticle carrier approaches for particle-free protection, such as improvements in conventional single carrier designs and new EUVL-specific carrier concepts, including variations on a removable pellicle. Our test indicates dual pod approach of the removable pellicle led to nearly particle-free use during a simulated life cycle, at ~50nm inspection sensitivity. We will provide an assessment of the remaining technical challenges facing EUVL reticle-handling technology. Finally, we will review the progress of the SEMI EUVL Reticle-handling Task Force in its efforts to standardize a final EUV reticle protection and handling solution.

Writing time estimation of EB mask writer EBM-9000 for hp16nm/logic11nm node generation

NASA Astrophysics Data System (ADS)

Kamikubo, Takashi; Takekoshi, Hidekazu; Ogasawara, Munehiro; Yamada, Hirokazu; Hattori, Kiyoshi

2014-10-01

The scaling of semiconductor devices is slowing down because of the difficulty in establishing their functionality at the nano-size level and also because of the limitations in fabrications, mainly the delay of EUV lithography. While multigate devices (FinFET) are currently the main driver for scalability, other types of devices, such as 3D devices, are being realized to relax the scaling of the node. In lithography, double or multiple patterning using ArF immersion scanners is still a realistic solution offered for the hp16nm node fabrication. Other lithography candidates are those called NGL (Next Generation Lithography), such as DSA (Directed-Self-Assembling) or nanoimprint. In such situations, shot count for mask making by electron beam writers will not increase. Except for some layers, it is not increasing as previously predicted. On the other hand, there is another aspect that increases writing time. The exposure dose for mask writing is getting higher to meet tighter specifications of CD uniformity, in other words, reduce LER. To satisfy these requirements, a new electron beam mask writer, EBM-9000, has been developed for hp16nm/logic11nm generation. Electron optical system, which has the immersion lens system, was evolved from EBM-8000 to achieve higher current density of 800A/cm2. In this paper, recent shot count and dose trend are discussed. Also, writing time is estimated for the requirements in EBM-9000.

Spin-on metal oxide materials with high etch selectivity and wet strippability

NASA Astrophysics Data System (ADS)

Yao, Huirong; Mullen, Salem; Wolfer, Elizabeth; McKenzie, Douglas; Rahman, Dalil; Cho, JoonYeon; Padmanaban, Munirathna; Petermann, Claire; Hong, SungEun; Her, YoungJun

2016-03-01

Metal oxide or metal nitride films are used as hard mask materials in semiconductor industry for patterning purposes due to their excellent etch resistances against the plasma etches. Chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques are usually used to deposit the metal containing materials on substrates or underlying films, which uses specialized equipment and can lead to high cost-of-ownership and low throughput. We have reported novel spin-on coatings that provide simple and cost effective method to generate metal oxide films possessing good etch selectivity and can be removed by chemical agents. In this paper, new spin-on Al oxide and Zr oxide hard mask formulations are reported. The new metal oxide formulations provide higher metal content compared to previously reported material of specific metal oxides under similar processing conditions. These metal oxide films demonstrate ultra-high etch selectivity and good pattern transfer capability. The cured films can be removed by various chemical agents such as developer, solvents or wet etchants/strippers commonly used in the fab environment. With high metal MHM material as an underlayer, the pattern transfer process is simplified by reducing the number of layers in the stack and the size of the nano structure is minimized by replacement of a thicker film ACL. Therefore, these novel AZ® spinon metal oxide hard mask materials can potentially be used to replace any CVD or ALD metal, metal oxide, metal nitride or spin-on silicon-containing hard mask films in 193 nm or EUV process.

Real-time line-width measurements: a new feature for reticle inspection systems

NASA Astrophysics Data System (ADS)

Eran, Yair; Greenberg, Gad; Joseph, Amnon; Lustig, Cornel; Mizrahi, Eyal

1997-07-01

The significance of line width control in mask production has become greater with the lessening of defect size. There are two conventional methods used for controlling line widths dimensions which employed in the manufacturing of masks for sub micron devices. These two methods are the critical dimensions (CD) measurement and the detection of edge defects. Achieving reliable and accurate control of line width errors is one of the most challenging tasks in mask production. Neither of the two methods cited above (namely CD measurement and the detection of edge defects) guarantees the detection of line width errors with good sensitivity over the whole mask area. This stems from the fact that CD measurement provides only statistical data on the mask features whereas applying edge defect detection method checks defects on each edge by itself, and does not supply information on the combined result of error detection on two adjacent edges. For example, a combination of a small edge defect together with a CD non- uniformity which are both within the allowed tolerance, may yield a significant line width error, which will not be detected using the conventional methods (see figure 1). A new approach for the detection of line width errors which overcomes this difficulty is presented. Based on this approach, a new sensitive line width error detector was developed and added to Orbot's RT-8000 die-to-database reticle inspection system. This innovative detector operates continuously during the mask inspection process and scans (inspects) the entire area of the reticle for line width errors. The detection is based on a comparison of measured line width that are taken on both the design database and the scanned image of the reticle. In section 2, the motivation for developing this new detector is presented. The section covers an analysis of various defect types, which are difficult to detect using conventional edge detection methods or, alternatively, CD measurements. In section 3, the basic concept of the new approach is introduced together with a description of the new detector and its characteristics. In section 4, the calibration process that took place in order to achieve reliable and repeatable line width measurements is presented. The description of an experiments conducted in order to evaluate the sensitivity of the new detector is given in section 5, followed by a report of the results of this evaluation. The conclusions are presented in section 6.

Validation of optical codes based on 3D nanostructures

NASA Astrophysics Data System (ADS)

Carnicer, Artur; Javidi, Bahram

2017-05-01

Image information encoding using random phase masks produce speckle-like noise distributions when the sample is propagated in the Fresnel domain. As a result, information cannot be accessed by simple visual inspection. Phase masks can be easily implemented in practice by attaching cello-tape to the plain-text message. Conventional 2D-phase masks can be generalized to 3D by combining glass and diffusers resulting in a more complex, physical unclonable function. In this communication, we model the behavior of a 3D phase mask using a simple approach: light is propagated trough glass using the angular spectrum of plane waves whereas the diffusor is described as a random phase mask and a blurring effect on the amplitude of the propagated wave. Using different designs for the 3D phase mask and multiple samples, we demonstrate that classification is possible using the k-nearest neighbors and random forests machine learning algorithms.

Green binary and phase shifting mask

NASA Astrophysics Data System (ADS)

Shy, S. L.; Hong, Chao-Sin; Wu, Cheng-San; Chen, S. J.; Wu, Hung-Yu; Ting, Yung-Chiang

2009-12-01

SixNy/Ni thin film green mask blanks were developed , and are now going to be used to replace general chromium film used for binary mask as well as to replace molydium silicide embedded material for AttPSM for I-line (365 nm), KrF (248 nm), ArF (193 nm) and Contact/Proximity lithography. A bilayer structure of a 1 nm thick opaque, conductive nickel layer and a SixNy layer is proposed for binary and phase-shifting mask. With the good controlling of plasma CVD of SixNy under silane (50 sccm), ammonia (5 sccm) and nitrogen (100 sccm), the pressure is 250 mTorr. and RF frequency 13.56 MHz and power 50 W. SixNy has enough deposition latitude to meet the requirements as an embedded layer for required phase shift 180 degree, and the T% in 193, 248 and 365 nm can be adjusted between 2% to 20% for binary and phase shifting mask usage. Ni can be deposited by E-gun, its sheet resistance Rs is less than 1.435 kΩ/square. Jeol e-beam system and I-line stepper are used to evaluate these thin film green mask blanks, feature size less than 200 nm half pitch pattern and 0.558 μm pitch contact hole can be printed. Transmission spectrums of various thickness of SixNy film are inspected by using UV spectrometer and FTIR. Optical constants of the SixNy film are measured by n & k meter and surface roughness is inspected by using Atomic Force Microscope (AFM).

150-nm DR contact holes die-to-database inspection

NASA Astrophysics Data System (ADS)

Kuo, Shen C.; Wu, Clare; Eran, Yair; Staud, Wolfgang; Hemar, Shirley; Lindman, Ofer

2000-07-01

Using a failure analysis-driven yield enhancements concept, based on an optimization of the mask manufacturing process and UV reticle inspection is studied and shown to improve the contact layer quality. This is achieved by relating various manufacturing processes to very fine tuned contact defect detection. In this way, selecting an optimized manufacturing process with fine-tuned inspection setup is achieved in a controlled manner. This paper presents a study, performed on a specially designed test reticle, which simulates production contact layers of design rule 250nm, 180nm and 150nm. This paper focuses on the use of advanced UV reticle inspection techniques as part of the process optimization cycle. Current inspection equipment uses traditional and insufficient methods of small contact-hole inspection and review.

Removable pellicle for lithographic mask protection and handling

DOEpatents

Klebanoff, Leonard E.; Rader, Daniel J.; Hector, Scott D.; Nguyen, Khanh B.; Stulen, Richard H.

2002-01-01

A removable pellicle for a lithographic mask that provides active and robust particle protection, and which utilizes a traditional pellicle and two deployments of thermophoretic protection to keep particles off the mask. The removable pellicle is removably attached via a retaining structure to the mask substrate by magnetic attraction with either contacting or non-contacting magnetic capture mechanisms. The pellicle retaining structural is composed of an anchor piece secured to the mask substrate and a frame member containing a pellicle. The anchor piece and the frame member are in removable contact or non-contact by the magnetic capture or latching mechanism. In one embodiment, the frame member is retained in a floating (non-contact) relation to the anchor piece by magnetic levitation. The frame member and the anchor piece are provided with thermophoretic fins which are interdigitated to prevent particles from reaching the patterned area of the mask. Also, the anchor piece and mask are maintained at a higher temperature than the frame member and pellicle which also prevents particles from reaching the patterned mask area by thermophoresis. The pellicle can be positioned over the mask to provide particle protection during mask handling, inspection, and pumpdown, but which can be removed manually or robotically for lithographic use of the mask.

Photomask quality evaluation using lithography simulation and multi-detector MVM-SEM

NASA Astrophysics Data System (ADS)

Ito, Keisuke; Murakawa, Tsutomu; Fukuda, Naoki; Shida, Soichi; Iwai, Toshimichi; Matsumoto, Jun; Nakamura, Takayuki; Matsushita, Shohei; Hagiwara, Kazuyuki; Hara, Daisuke

2013-06-01

The detection and management of mask defects which are transferred onto wafer becomes more important day by day. As the photomask patterns becomes smaller and more complicated, using Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO) with Optical Proximity Correction (OPC). To evaluate photomask quality, the current method uses aerial imaging by optical inspection tools. This technique at 1Xnm node has a resolution limit because small defects will be difficult to detect. We already reported the MEEF influence of high-end photomask using wide FOV SEM contour data of "E3630 MVM-SEM®" and lithography simulator "TrueMask® DS" of D2S Inc. in the prior paper [1]. In this paper we evaluate the correlation between our evaluation method and optical inspection tools as ongoing assessment. Also in order to reduce the defect classification work, we can compose the 3 Dimensional (3D) information of defects and can judge whether repairs of defects would be required. Moreover, we confirm the possibility of wafer plane CD measurement based on the combination between E3630 MVM-SEM® and 3D lithography simulation.

Increasing reticle inspection efficiency and reducing wafer printchecks at 14nm using automated defect classification and simulation

NASA Astrophysics Data System (ADS)

Paracha, Shazad; Goodman, Eliot; Eynon, Benjamin G.; Noyes, Ben F.; Ha, Steven; Kim, Jong-Min; Lee, Dong-Seok; Lee, Dong-Heok; Cho, Sang-Soo; Ham, Young M.; Vacca, Anthony D.; Fiekowsky, Peter J.; Fiekowsky, Daniel I.

2014-10-01

IC fabs inspect critical masks on a regular basis to ensure high wafer yields. These requalification inspections are costly for many reasons including the capital equipment, system maintenance, and labor costs. In addition, masks typically remain in the "requal" phase for extended, non-productive periods of time. The overall "requal" cycle time in which reticles remain non-productive is challenging to control. Shipping schedules can slip when wafer lots are put on hold until the master critical layer reticle is returned to production. Unfortunately, substituting backup critical layer reticles can significantly reduce an otherwise tightly controlled process window adversely affecting wafer yields. One major requal cycle time component is the disposition process of mask inspections containing hundreds of defects. Not only is precious non-productive time extended by reviewing hundreds of potentially yield-limiting detections, each additional classification increases the risk of manual review techniques accidentally passing real yield limiting defects. Even assuming all defects of interest are flagged by operators, how can any person's judgment be confident regarding lithographic impact of such defects? The time reticles spend away from scanners combined with potential yield loss due to lithographic uncertainty presents significant cycle time loss and increased production costs An automatic defect analysis system (ADAS), which has been in fab production for numerous years, has been improved to handle the new challenges of 14nm node automate reticle defect classification by simulating each defect's printability under the intended illumination conditions. In this study, we have created programmed defects on a production 14nm node critical-layer reticle. These defects have been analyzed with lithographic simulation software and compared to the results of both AIMS optical simulation and to actual wafer prints.

Reentry Vehicle On-Site Inspection Technology Study

DTIC Science & Technology

1994-11-01

masking Image Additional required* generated information required/wquied Pasive radiation Neutron scanning Neutron dose rate PNS Yes No SRS/BMO Yes...considerations for RVOSI techbologles. Inspection methods Instrument Setup Data Host support proximity time collection (m) (hr) time (hir) Pasive radiation...The unwillingness of our own services to allow equipment in close proximity to missile front ends is a matter which will have to be considered if a

3D Microfabrication Using Emulsion Mask Grayscale Photolithography Technique

NASA Astrophysics Data System (ADS)

Lee, Tze Pin; Mohamed, Khairudin

2016-02-01

Recently, the rapid development of technology such as biochips, microfluidic, micro-optical devices and micro-electromechanical-systems (MEMS) demands the capability to create complex design of three-dimensional (3D) microstructures. In order to create 3D microstructures, the traditional photolithography process often requires multiple photomasks to form 3D pattern from several stacked photoresist layers. This fabrication method is extremely time consuming, low throughput, costly and complicated to conduct for high volume manufacturing scale. On the other hand, next generation lithography such as electron beam lithography (EBL), focused ion beam lithography (FIB) and extreme ultraviolet lithography (EUV) are however too costly and the machines require expertise to setup. Therefore, the purpose of this study is to develop a simplified method in producing 3D microstructures using single grayscale emulsion mask technique. By using this grayscale fabrication method, microstructures of thickness as high as 500μm and as low as 20μm are obtained in a single photolithography exposure. Finally, the fabrication of 3D microfluidic channel has been demonstrated by using this grayscale photolithographic technique.

Automated mask and wafer defect classification using a novel method for generalized CD variation measurements

NASA Astrophysics Data System (ADS)

Verechagin, V.; Kris, R.; Schwarzband, I.; Milstein, A.; Cohen, B.; Shkalim, A.; Levy, S.; Price, D.; Bal, E.

2018-03-01

Over the years, mask and wafers defects dispositioning has become an increasingly challenging and time consuming task. With design rules getting smaller, OPC getting complex and scanner illumination taking on free-form shapes - the probability of a user to perform accurate and repeatable classification of defects detected by mask inspection tools into pass/fail bins is reducing. The critical challenging of mask defect metrology for small nodes ( < 30 nm) was reviewed in [1]. While Critical Dimension (CD) variation measurement is still the method of choice for determining a mask defect future impact on wafer, the high complexity of OPCs combined with high variability in pattern shapes poses a challenge for any automated CD variation measurement method. In this study, a novel approach for measurement generalization is presented. CD variation assessment performance is evaluated on multiple different complex shape patterns, and is benchmarked against an existing qualified measurement methodology.

Mask pattern generator employing EPL technology

NASA Astrophysics Data System (ADS)

Yoshioka, Nobuyuki; Yamabe, Masaki; Wakamiya, Wataru; Endo, Nobuhiro

2003-08-01

Mask cost is one of crucial issues in device fabrication, especially in SoC (System on a Chip) with small-volume production. The cost mainly depends on productivity of mask manufacturing tools such as mask writers and defect inspection tools. EPL (Electron Projection Lithography) has been developing as a high-throughput electron beam exposure technology that will succeed optical lithography. The application of EPL technology to mask writing will result in high productivity and contribute to decrease the mask cost. The concept of a mask pattern generator employing EPL technology is proposed in this paper. It is very similar to EPL technology used for pattern printing on a wafer. The mask patterns on the glass substrate are exposed by projecting the basic circuit patterns formed on the mother EPL mask. One example of the mother EPL mask is a stencil type made with 200-mm Si wafer. The basic circuit patterns are IP patterns and logical primitive patterns such as cell libraries (AND, OR, Inverter, Flip-Flop and etc.) to express the SoC device patterns. Since the SoC patterns are exposed with its collective units such as IP and logical primitive patterns by using this method, the high throughput will be expected comparing with conventional mask E-beam writers. In this paper, the mask pattern generator with the EPL technology is proposed. The concept, its advantages and issues to be solved are discussed.

Reticles, write time, and the need for speed

NASA Astrophysics Data System (ADS)

Ackmann, Paul W.; Litt, Lloyd C.; Ning, Guo Xiang

2014-10-01

Historical data indicates reticle write times are increasing node-to-node. The cost of mask sets is increasing driven by the tighter requirements and more levels. The regular introduction of new generations of mask patterning tools with improved performance is unable to fully compensate for the increased data and complexity required. Write time is a primary metric that drives mask fabrication speed. Design (Raw data) is only the first step in the process and many interactions between mask and wafer technology such as OPC used, OPC efficiency for writers, fracture engines, and actual field size used drive total write time. Yield, technology, and inspection rules drive the remaining raw cycle time. Yield can be even more critical for speed of delivery as it drives re-writes and wasted time. While intrinsic process yield is important, repair capability is the reason mask delivery is still able to deliver 100% good reticles to the fab. Advanced nodes utilizing several layers of multiple patterning may require mask writer tool dedication to meet image placement specifications. This will increase the effective mask cycle time for a layer mask set and drive the need for additional mask write capability in order to deliver masks at the rate required by the wafer fab production schedules.

LENS (lithography enhancement toward nano scale): a European project to support double exposure and double patterning technology development

NASA Astrophysics Data System (ADS)

Cantu, Pietro; Baldi, Livio; Piacentini, Paolo; Sytsma, Joost; Le Gratiet, Bertrand; Gaugiran, Stéphanie; Wong, Patrick; Miyashita, Hiroyuki; Atzei, Luisa R.; Buch, Xavier; Verkleij, Dick; Toublan, Olivier; Perez-Murano, Francesco; Mecerreyes, David

2010-04-01

In 2009 a new European initiative on Double Patterning and Double Exposure lithography process development was started in the framework of the ENIAC Joint Undertaking. The project, named LENS (Lithography Enhancement Towards Nano Scale), involves twelve companies from five different European Countries (Italy, Netherlands, France, Belgium Spain; includes: IC makers (Numonyx and STMicroelectronics), a group of equipment and materials companies (ASML, Lam Research srl, JSR, FEI), a mask maker (Dai Nippon Photomask Europe), an EDA company (Mentor Graphics) and four research and development institutes (CEA-Leti, IMEC, Centro Nacional de Microelectrónica, CIDETEC). The LENS project aims to develop and integrate the overall infrastructure required to reach patterning resolutions required by 32nm and 22nm technology nodes through the double patterning and pitch doubling technologies on existing conventional immersion exposure tools, with the purpose to allow the timely development of 32nm and 22nm technology nodes for memories and logic devices, providing a safe alternative to EUV, Higher Refraction Index Fluids Immersion Lithography and maskless lithography, which appear to be still far from maturity. The project will cover the whole lithography supply chain including design, masks, materials, exposure tools, process integration, metrology and its final objective is the demonstration of 22nm node patterning on available 1.35 NA immersion tools on high complexity mask set.

Automated reticle inspection data analysis for wafer fabs

NASA Astrophysics Data System (ADS)

Summers, Derek; Chen, Gong; Reese, Bryan; Hutchinson, Trent; Liesching, Marcus; Ying, Hai; Dover, Russell

2008-10-01

To minimize potential wafer yield loss due to mask defects, most wafer fabs implement some form of reticle inspection system to monitor photomask quality in high-volume wafer manufacturing environments. Traditionally, experienced operators review reticle defects found by an inspection tool and then manually classify each defect as 'pass, warn, or fail' based on its size and location. However, in the event reticle defects are suspected of causing repeating wafer defects on a completed wafer, potential defects on all associated reticles must be manually searched on a layer-by-layer basis in an effort to identify the reticle responsible for the wafer yield loss. This 'problem reticle' search process is a very tedious and time-consuming task and may cause extended manufacturing line-down situations. Often times, Process Engineers and other team members need to manually investigate several reticle inspection reports to determine if yield loss can be tied to a specific layer. Because of the very nature of this detailed work, calculation errors may occur resulting in an incorrect root cause analysis effort. These delays waste valuable resources that could be spent working on other more productive activities. This paper examines an automated software solution for converting KLA-Tencor reticle inspection defect maps into a format compatible with KLA-Tencor's Klarity DefecTM data analysis database. The objective is to use the graphical charting capabilities of Klarity Defect to reveal a clearer understanding of defect trends for individual reticle layers or entire mask sets. Automated analysis features include reticle defect count trend analysis and potentially stacking reticle defect maps for signature analysis against wafer inspection defect data. Other possible benefits include optimizing reticle inspection sample plans in an effort to support "lean manufacturing" initiatives for wafer fabs.

Automated reticle inspection data analysis for wafer fabs

NASA Astrophysics Data System (ADS)

Summers, Derek; Chen, Gong; Reese, Bryan; Hutchinson, Trent; Liesching, Marcus; Ying, Hai; Dover, Russell

2009-04-01

To minimize potential wafer yield loss due to mask defects, most wafer fabs implement some form of reticle inspection system to monitor photomask quality in high-volume wafer manufacturing environments. Traditionally, experienced operators review reticle defects found by an inspection tool and then manually classify each defect as 'pass, warn, or fail' based on its size and location. However, in the event reticle defects are suspected of causing repeating wafer defects on a completed wafer, potential defects on all associated reticles must be manually searched on a layer-by-layer basis in an effort to identify the reticle responsible for the wafer yield loss. This 'problem reticle' search process is a very tedious and time-consuming task and may cause extended manufacturing line-down situations. Often times, Process Engineers and other team members need to manually investigate several reticle inspection reports to determine if yield loss can be tied to a specific layer. Because of the very nature of this detailed work, calculation errors may occur resulting in an incorrect root cause analysis effort. These delays waste valuable resources that could be spent working on other more productive activities. This paper examines an automated software solution for converting KLA-Tencor reticle inspection defect maps into a format compatible with KLA-Tencor's Klarity Defect(R) data analysis database. The objective is to use the graphical charting capabilities of Klarity Defect to reveal a clearer understanding of defect trends for individual reticle layers or entire mask sets. Automated analysis features include reticle defect count trend analysis and potentially stacking reticle defect maps for signature analysis against wafer inspection defect data. Other possible benefits include optimizing reticle inspection sample plans in an effort to support "lean manufacturing" initiatives for wafer fabs.

Automated reticle inspection data analysis for wafer fabs

NASA Astrophysics Data System (ADS)

Summers, Derek; Chen, Gong; Reese, Bryan; Hutchinson, Trent; Liesching, Marcus; Ying, Hai; Dover, Russell

2009-03-01

To minimize potential wafer yield loss due to mask defects, most wafer fabs implement some form of reticle inspection system to monitor photomask quality in high-volume wafer manufacturing environments. Traditionally, experienced operators review reticle defects found by an inspection tool and then manually classify each defect as 'pass, warn, or fail' based on its size and location. However, in the event reticle defects are suspected of causing repeating wafer defects on a completed wafer, potential defects on all associated reticles must be manually searched on a layer-by-layer basis in an effort to identify the reticle responsible for the wafer yield loss. This 'problem reticle' search process is a very tedious and time-consuming task and may cause extended manufacturing line-down situations. Often times, Process Engineers and other team members need to manually investigate several reticle inspection reports to determine if yield loss can be tied to a specific layer. Because of the very nature of this detailed work, calculation errors may occur resulting in an incorrect root cause analysis effort. These delays waste valuable resources that could be spent working on other more productive activities. This paper examines an automated software solution for converting KLA-Tencor reticle inspection defect maps into a format compatible with KLA-Tencor's Klarity DefectTM data analysis database. The objective is to use the graphical charting capabilities of Klarity Defect to reveal a clearer understanding of defect trends for individual reticle layers or entire mask sets. Automated analysis features include reticle defect count trend analysis and potentially stacking reticle defect maps for signature analysis against wafer inspection defect data. Other possible benefits include optimizing reticle inspection sample plans in an effort to support "lean manufacturing" initiatives for wafer fabs.

First 65nm tape-out using inverse lithography technology (ILT)

NASA Astrophysics Data System (ADS)

Hung, Chi-Yuan; Zhang, Bin; Tang, Deming; Guo, Eric; Pang, Linyong; Liu, Yong; Moore, Andrew; Wang, Kechang

2005-11-01

This paper presents SMIC's first 65nm tape out results, in particularly, using ILT. ILT mathematically determines the mask features that produce the desired on-wafer results with best wafer pattern fidelity, largest process window or both. SMIC applied it to its first 65nm tape-out to study ILT performance and benefits for deep sub-wavelength lithography. SMIC selected 3 SRAM designs as the first test case, because SRAM bit-cells contain features which are challenging lithographically. Mask patterns generated from both conventional OPC and ILT were placed on the mask side-by-side. Mask manufacturability (including fracturing, writing time, inspection, and metrology) and wafer print performance of ILT were studied. The results demonstrated that ILT achieved better CD accuracy, produced substantially larger process window than conventional OPC, and met SMIC's 65nm process window requirements.

High-NA EUV projection lens with central obscuration

NASA Astrophysics Data System (ADS)

Zhevlakov, A. P.; Seisyan, R. P.; Bespalov, V. G.; Elizarov, V. V.; Grishkanich, A. S.; Kascheev, S. V.; Bagdasarov, A. A.; Sidorov, I. S.

2016-03-01

The lenses with coaxial mirrors allow obtain NA values up to of 0.8 and demagnification β >=10. The larger β value leads to the mask cost reducing, as in this case, the elements of the IC pattern template can be made bigger and, therefore, with fewer defects. Coaxial schemes can engender a problem of the image plane shift beyond the projection lens element boundaries near the wafer. The projection lens consisting of four coaxial mirrors with NA= 0.485 and s = 12 combined with the "Vanguard" imaging subsystem have been designed. According to the computation the circuit features at 10 nm in center and 20 nm on the edge of 12.4 mm field of view can be imaged.

Prospective EUV observations of hot DA white dwarfs with the EUV Explorer

NASA Technical Reports Server (NTRS)

Finley, David S.; Malina, Roger F.; Bowyer, Stuart

1987-01-01

The Extreme Ultraviolet Explorer (EUVE) will perform a high sensitivity EUV all-sky survey. A major category of sources which will be detected with the EUVE instruments consists of hot white dwarfs. Detailed preliminary studies of synthetic EUV observations of white dwarfs have been carried out using the predicted EUVE instrumental response functions. Using available information regarding space densities of white dwarfs and the distribution of neutral hydrogen in the interstellar medium, the numbers of DA white dwarfs which will be detectable in the different EUV bandpasses have been estimated.

Reticle haze: an industrial approach

NASA Astrophysics Data System (ADS)

Gough, Stuart; Gérard, Xavier; Bichebois, Pascal; Roche, Agnès; Sundermann, Frank; Guyader, Véronique; Bièron, Yann; Galvier, Jean; Nicoleau, Serge

2007-02-01

Crystal growth on advanced reticles is currently a world wide industrial problem in high end semiconductor production environment, crystals are mainly found on reticles that use high energy photons at 193nm wavelength. The most common crystals to be found on masks are ammonium sulphate, a combination of sulphate, from maskshop residues after clean, pellicle materials and storage conditions and amines from clean room, tool and storage environments. High energy photons act as a catalyst to form crystals on both the pattern side as well as the backglass surface. After a number of exposures crystals can grow in size and eventually become printable. In order to detect HAZE before critical dimensions have been reached suitable detection methods need to be implemented to ensure image integrity. These detection methods are different and complementary depending on the surface to be inspected. Once crystals have started growing, the only method to regain mask quality is to clean the mask at the manufacturers site. This brings with it several undesirable situations, not only is the mask unavailable for production but the cleaning of a mask leads to a potential risk of damaging the mask especially for sub resolution patterns such as scatter bars and phase and transmission changes for eaPSM (Embedded Attenuated Phase Shift Mask) masks. This paper will discuss the initial haze issues seen in a 300mm wafer fab and actions put in place to address the problem. An explanation of results gained from haze reduction actions implemented in a wafer fab will be given. Haze seen by reticle inspection and surface analysis tools can be characterised by typical contamination patterns. These signatures appear after a certain number of wafers exposed depending on several reticle variables such as transmission, Binary, eaPSM, Pellicle. Details will be given of how reticles are managed to ensure minimum impact to a production environment with an appropriate reticle control plan. AMC (Airborne Molecular Contamination) in wafer fab and equipment environment is a key factor for crystal growth. The type of filtration installed to reduce AMC and method of atmospheric monitoring for critical areas will be explained. Choice of reticle storage conditions and materials used for transport during the life of the reticle will be included. Improvements in maskshop cleaning processes, reticle materials and environmental control have lead to extended mask lifetime in the wafer fab of more than 20 times. The fundamental differences and relative monitoring will be described and gain from implemented actions will be presented Once crystals have started growing, the only method to regain mask quality is to clean the mask at the manufacturers site. This brings with it several undesirable situations, not only is the mask unavailable for production but the cleaning of a mask leads to a potential risk of damaging the mask especially for sub resolution patterns such as scatter bars and phase and transmission changes for eaPSM (Embedded Attenuated Phase Shift Mask) masks. This paper will discuss the initial haze issues seen in a 300mm wafer fab and actions put in place to address the problem. An explanation of results gained from haze reduction actions implemented in a wafer fab will be given. Haze seen by reticle inspection and surface analysis tools can be characterised by typical contamination patterns. These signatures appear after a certain number of wafers exposed depending on several reticle variables such as transmission, Binary, eaPSM, Pellicle. Details will be given of how reticles are managed to ensure minimum impact to a production environment with an appropriate reticle control plan. AMC (Airborne Molecular Contamination) in wafer fab and equipment environment is a key factor for crystal growth. The type of filtration installed to reduce AMC and method of atmospheric monitoring for critical areas will be explained. Choice of reticle storage conditions and materials used for transport during the life of the reticle will be included. Improvements in maskshop cleaning processes, reticle materials and environmental control have lead to extended mask lifetime in the wafer fab of more than 20 times. The fundamental differences and relative monitoring will be described and gain from implemented actions will be presented

The role of the faceguard in the production of flexion injuries to the cervical spine in football.

PubMed

Melvin, W J; Dunlop, H W; Hetherington, R F; Kerr, J W

1965-11-20

The precise role of the single-bar face mask in producing major flexion violence to the cervical spine has been studied by review of game movies, analysis of the radiographs and detailed interviews with two players who sustained fractures of cervical spine. The single-bar face mask can become fixed in the ground, thereby forcing a runner's head down onto his chest as the trunk moves forward. Preventive measures embodying modifications in the face mask, strict coaching in football techniques and the institution of safety factors in the playing rules are proposed. Appreciation of the mechanism of injury is urged in order to encourage careful inspection of protective head gear as well as to direct the attention of team physicians to the possibility of serious flexion injury to the cervical spine occurring without dramatic evidence. This report is not a plea for abandonment of the face mask but rather a suggestion for careful selection of a safe and efficient mask.

Strategy optimization for mask rule check in wafer fab

NASA Astrophysics Data System (ADS)

Yang, Chuen Huei; Lin, Shaina; Lin, Roger; Wang, Alice; Lee, Rachel; Deng, Erwin

2015-07-01

Photolithography process is getting more and more sophisticated for wafer production following Moore's law. Therefore, for wafer fab, consolidated and close cooperation with mask house is a key to achieve silicon wafer success. However, generally speaking, it is not easy to preserve such partnership because many engineering efforts and frequent communication are indispensable. The inattentive connection is obvious in mask rule check (MRC). Mask houses will do their own MRC at job deck stage, but the checking is only for identification of mask process limitation including writing, etching, inspection, metrology, etc. No further checking in terms of wafer process concerned mask data errors will be implemented after data files of whole mask are composed in mask house. There are still many potential data errors even post-OPC verification has been done for main circuits. What mentioned here are the kinds of errors which will only occur as main circuits combined with frame and dummy patterns to form whole reticle. Therefore, strategy optimization is on-going in UMC to evaluate MRC especially for wafer fab concerned errors. The prerequisite is that no impact on mask delivery cycle time even adding this extra checking. A full-mask checking based on job deck in gds or oasis format is necessary in order to secure acceptable run time. Form of the summarized error report generated by this checking is also crucial because user friendly interface will shorten engineers' judgment time to release mask for writing. This paper will survey the key factors of MRC in wafer fab.

Analysis method to determine and characterize the mask mean-to-target and uniformity specification

NASA Astrophysics Data System (ADS)

Lee, Sung-Woo; Leunissen, Leonardus H. A.; Van de Kerkhove, Jeroen; Philipsen, Vicky; Jonckheere, Rik; Lee, Suk-Joo; Woo, Sang-Gyun; Cho, Han-Ku; Moon, Joo-Tae

2006-06-01

The specification of the mask mean-to-target (MTT) and uniformity is related to functions as: mask error enhancement factor, dose sensitivity and critical dimension (CD) tolerances. The mask MTT shows a trade-off relationship with the uniformity. Simulations for the mask MTT and uniformity (M-U) are performed for LOGIC devices of 45 and 37 nm nodes according to mask type, illumination condition and illuminator polarization state. CD tolerances and after develop inspection (ADI) target CD's in the simulation are taken from the 2004 ITRS roadmap. The simulation results allow for much smaller tolerances in the uniformity and larger offsets in the MTT than the values as given in the ITRS table. Using the parameters in the ITRS table, the mask uniformity contributes to nearly 95% of total CDU budget for the 45 nm node, and is even larger than the CDU specification of the ITRS for the 37 nm node. We also compared the simulation requirements with the current mask making capabilities. The current mask manufacturing status of the mask uniformity is barely acceptable for the 45 nm node, but requires process improvements towards future nodes. In particular, for the 37 nm node, polarized illumination is necessary to meet the ITRS requirements. The current mask linearity deviates for pitches smaller than 300 nm, which is not acceptable even for the 45 nm node. More efforts on the proximity correction method are required to improve the linearity behavior.

Nanoparticle contamination control for EUVL-technology: especially for photomasks in carriers and scanners

NASA Astrophysics Data System (ADS)

Fissan, Heinz; Asbach, Christof; Kuhlbusch, Thomas A. J.; Wang, Jing; Pui, David Y. H.; Yook, Se-Jin; Kim, Jung H.

2009-05-01

Extreme Ultraviolet Lithography (EUVL) is a leading lithography technology for the sub-32 nm chip manufacturing technology. Photomasks, in a mask carrier or inside a vacuum scanner, need to be protected from contamination by nanoparticles larger than the minimum feature size expected from this technology. The most critical part with respect to contamination in the EUVL-system is the photomask. The protection is made more difficult because protective pellicles cannot be used, due to the attenuation of the EUV beam by the pellicle. We have defined a set of protection schemes to protect EUVL photomasks from particle contamination and developed models to describe their effectiveness at atmospheric pressure (e.g. in mask carriers) or during scanning operation at low pressure. These schemes include that the mask is maintained facing down to avoid gravitational settling and the establishment of a thermal gradient underneath the mask surface to thermophoretically repel particles. Experimental verification studies of the models were carried out in atmospheric-pressure carriers and in a vacuum system down to about 3.3 Pa. Particles with sizes between 60 (for experiments, isn't it 125 nm?) nm and 250 nm were injected into the vacuum chamber with controlled speed and concentration to validate the analytical and numerical models. It could be shown that a deterministic approach using free molecular expressions can be used to accurately describe particle deposition at these low pressure levels. Thermophoresis was found to be very effective at both atmospheric and low pressure against the diffusional particle deposition, whereas inertial particle deposition of large and/or fast particles can likely not be prevented. A review of the models and their verification will be presented in this paper.

Automatically high accurate and efficient photomask defects management solution for advanced lithography manufacture

NASA Astrophysics Data System (ADS)

Zhu, Jun; Chen, Lijun; Ma, Lantao; Li, Dejian; Jiang, Wei; Pan, Lihong; Shen, Huiting; Jia, Hongmin; Hsiang, Chingyun; Cheng, Guojie; Ling, Li; Chen, Shijie; Wang, Jun; Liao, Wenkui; Zhang, Gary

2014-04-01

Defect review is a time consuming job. Human error makes result inconsistent. The defects located on don't care area would not hurt the yield and no need to review them such as defects on dark area. However, critical area defects can impact yield dramatically and need more attention to review them such as defects on clear area. With decrease in integrated circuit dimensions, mask defects are always thousands detected during inspection even more. Traditional manual or simple classification approaches are unable to meet efficient and accuracy requirement. This paper focuses on automatic defect management and classification solution using image output of Lasertec inspection equipment and Anchor pattern centric image process technology. The number of mask defect found during an inspection is always in the range of thousands or even more. This system can handle large number defects with quick and accurate defect classification result. Our experiment includes Die to Die and Single Die modes. The classification accuracy can reach 87.4% and 93.3%. No critical or printable defects are missing in our test cases. The missing classification defects are 0.25% and 0.24% in Die to Die mode and Single Die mode. This kind of missing rate is encouraging and acceptable to apply on production line. The result can be output and reloaded back to inspection machine to have further review. This step helps users to validate some unsure defects with clear and magnification images when captured images can't provide enough information to make judgment. This system effectively reduces expensive inline defect review time. As a fully inline automated defect management solution, the system could be compatible with current inspection approach and integrated with optical simulation even scoring function and guide wafer level defect inspection.

A novel methodology for building robust design rules by using design based metrology (DBM)

NASA Astrophysics Data System (ADS)

Lee, Myeongdong; Choi, Seiryung; Choi, Jinwoo; Kim, Jeahyun; Sung, Hyunju; Yeo, Hyunyoung; Shim, Myoungseob; Jin, Gyoyoung; Chung, Eunseung; Roh, Yonghan

2013-03-01

This paper addresses a methodology for building robust design rules by using design based metrology (DBM). Conventional method for building design rules has been using a simulation tool and a simple pattern spider mask. At the early stage of the device, the estimation of simulation tool is poor. And the evaluation of the simple pattern spider mask is rather subjective because it depends on the experiential judgment of an engineer. In this work, we designed a huge number of pattern situations including various 1D and 2D design structures. In order to overcome the difficulties of inspecting many types of patterns, we introduced Design Based Metrology (DBM) of Nano Geometry Research, Inc. And those mass patterns could be inspected at a fast speed with DBM. We also carried out quantitative analysis on PWQ silicon data to estimate process variability. Our methodology demonstrates high speed and accuracy for building design rules. All of test patterns were inspected within a few hours. Mass silicon data were handled with not personal decision but statistical processing. From the results, robust design rules are successfully verified and extracted. Finally we found out that our methodology is appropriate for building robust design rules.

Extreme ultraviolet lithography machine

DOEpatents

Tichenor, Daniel A.; Kubiak, Glenn D.; Haney, Steven J.; Sweeney, Donald W.

2000-01-01

An extreme ultraviolet lithography (EUVL) machine or system for producing integrated circuit (IC) components, such as transistors, formed on a substrate. The EUVL machine utilizes a laser plasma point source directed via an optical arrangement onto a mask or reticle which is reflected by a multiple mirror system onto the substrate or target. The EUVL machine operates in the 10-14 nm wavelength soft x-ray photon. Basically the EUV machine includes an evacuated source chamber, an evacuated main or project chamber interconnected by a transport tube arrangement, wherein a laser beam is directed into a plasma generator which produces an illumination beam which is directed by optics from the source chamber through the connecting tube, into the projection chamber, and onto the reticle or mask, from which a patterned beam is reflected by optics in a projection optics (PO) box mounted in the main or projection chamber onto the substrate. In one embodiment of a EUVL machine, nine optical components are utilized, with four of the optical components located in the PO box. The main or projection chamber includes vibration isolators for the PO box and a vibration isolator mounting for the substrate, with the main or projection chamber being mounted on a support structure and being isolated.

X-ray/EUV optics for astronomy, microscopy, polarimetry, and projection lithography; Proceedings of the Meeting, San Diego, CA, July 9-13, 1990

NASA Technical Reports Server (NTRS)

Hoover, Richard B. (Editor); Walker, Arthur B. C., Jr. (Editor)

1991-01-01

Topics discussed in this issue include the fabrication of multilayer X-ray/EUV coatings; the design, characterization, and test of multilayer X-ray/EUV coatings; multilayer X-ray/EUV monochromators and imaging microscopes; X-ray/EUV telescopes; the test and calibration performance of X-ray/EUV instruments; XUV/soft X-ray projection lithography; X-ray/EUV space observatories and missions; X-ray/EUV telescopes for solar research; X-ray/EUV polarimetry; X-ray/EUV spectrographs; and X-ray/EUV filters and gratings. Papers are presented on the deposition-controlled uniformity of multilayer mirrors, interfaces in Mo/Si multilayers, the design and analysis of an aspherical multilayer imaging X-ray microscope, recent developments in the production of thin X-ray reflecting foils, and the ultraprecise scanning technology. Consideration is also given to an active sun telescope array, the fabrication and performance at 1.33 nm of a 0.24-micron-period multilayer grating, a cylindrical proportional counter for X-ray polarimetry, and the design and analysis of the reflection grating arrays for the X-Ray Multi-Mirror Mission.

In-line verification of linewidth uniformity for 0.18 and below: design rule reticles

NASA Astrophysics Data System (ADS)

Tan, TaiSheng; Kuo, Shen C.; Wu, Clare; Falah, Reuven; Hemar, Shirley; Sade, Amikam; Gottlib, Gidon

2000-07-01

Mask making process development and control is addressed using a reticle inspection tool equipped with the new revolutionized application called LBM-Linewidth Bias Monitoring. In order to use the LBM for mask-making process control, procedures and corresponding test plates are a developed, such that routine monitoring of the manufacturing process discloses process variation and machine variation. At the same time systematic variation are studied and either taken care of or taken into consideration to allow successful production line work. In this paper the contribution of the LBM for mask quality monitoring is studied with respect to dense layers, e.g. DRAM. Another aspect of this application - the detection of very small CD mis-uniformity areas is discussed.

Responses of Solar Irradiance and the Ionosphere to an Intense Activity Region

NASA Astrophysics Data System (ADS)

Chen, Yiding; Liu, Libo; Le, Huijun; Wan, Weixing

2018-03-01

Solar rotation (SR) variation dominates solar extremely ultraviolet (EUV) changes on the timescale of days. The F10.7 index is usually used as an indicator for solar EUV. The SR variation of F10.7 significantly enhanced during the 2008th-2009th Carrington rotations (CRs) owing to an intense active region; F10.7 increased about 180 units during that SR period. That was the most prominent SR variation of F10.7 during solar cycle 23. In this paper, global electron content (GEC) is used to investigate ionospheric response to that strong variation of solar irradiance indicated by F10.7. The variation of GEC with F10.7 was anomalous (GEC-F10.7 slope significantly decreased) during the 2008th-2009th CRs; however, GEC versus EUV variation during that period was consistent with that during adjacent time intervals when using Solar Heliospheric Observatory/Solar EUV Monitor 26-34 nm EUV measurements. The reason is that F10.7 response to that intense active region was much stronger than EUV response; thus, the EUV-F10.7 slope decreased. We confirmed decreased EUV-F10.7 slope during the 2008th-2009th CRs for different wavelengths within 27-120 nm using Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Solar EUV Experiment high spectral resolution EUV measurements. And on the basis of Solar Heliospheric Observatory/Solar EUV Monitor EUV measurements during solar cycle 23, we further presented that EUV-F10.7 slope statistically tends to decrease when the SR variation of F10.7 significantly enhances. Moreover, we found that ionospheric time lag effect to EUV is exaggerated when using F10.7, owing to the time lag effect of EUV to F10.7.

An intelligent system for real time automatic defect inspection on specular coated surfaces

NASA Astrophysics Data System (ADS)

Li, Jinhua; Parker, Johné M.; Hou, Zhen

2005-07-01

Product visual inspection is still performed manually or semi automatically in most industries from simple ceramic tile grading to complex automotive body panel paint defect and surface quality inspection. Moreover, specular surfaces present additional challenge to conventional vision systems due to specular reflections, which may mask the true location of objects and lead to incorrect measurements. There are some sophisticated visual inspection methods developed in recent years. Unfortunately, most of them are highly computational. Systems built on those methods are either inapplicable or very costly to achieve real time inspection. In this paper, we describe an integrated low-cost intelligent system developed to automatically capture, extract, and segment defects on specular surfaces with uniform color coatings. The system inspects and locates regular surface defects with lateral dimensions as small as a millimeter. The proposed system is implemented on a group of smart cameras using its on-board processing ability to achieve real time inspection. The experimental results on real test panels demonstrate the effectiveness and robustness of proposed system.

Aerial imaging technology for photomask qualification: from a microscope to a metrology tool

NASA Astrophysics Data System (ADS)

Garetto, Anthony; Scherübl, Thomas; Peters, Jan Hendrik

2012-09-01

Photomasks carry the structured information of the chip designs printed with lithography scanners onto wafers. These structures, for the most modern technologies, are enlarged by a factor of 4 with respect to the final circuit design, and 20-60 of these photomasks are needed for the production of a single completed chip used, for example, in computers or cell phones. Lately, designs have been reported to be on the drawing board with close to 100 of these layers. Each of these photomasks will be reproduced onto the wafer several hundred times and typically 5000-50 000 wafers will be produced with each of them. Hence, the photomasks need to be absolutely defect-free to avoid any fatal electrical shortcut in the design or drastic performance degradation. One well-known method in the semiconductor industry is to analyze the aerial image of the photomask in a dedicated tool referred to as Aerial Imaging Measurement System, which emulates the behavior of the respective lithography scanner used for the imaging of the mask. High-end lithography scanners use light with a wavelength of 193 nm and high numerical apertures (NAs) of 1.35 utilizing a water film between the last lens and the resist to be illuminated (immersion scanners). Complex illumination shapes enable the imaging of structures well below the wavelength used. Future lithography scanners will work at a wavelength of 13.5 nm [extreme ultraviolet (EUV)] and require the optical system to work with mirrors in vacuum instead of the classical lenses used in current systems. The exact behavior of these systems is emulated by the Aerial Image Measurement System (AIMS™; a Trademark of Carl Zeiss). With these systems, any position of the photomask can be imaged under the same illumination condition used by the scanners, and hence, a prediction of the printing behavior of any structure can be derived. This system is used by mask manufacturers in their process flow to review critical defects or verify defect repair success. In this paper, we give a short introduction into the lithography roadmap driving the development cycles of the AIMS systems focusing primarily on the complexity of the structures to be reviewed. Second, we describe the basic principle of the AIMS technology and how it is used. The last section is dedicated to the development of the latest generation of the AIMS for EUV, which is cofinanced by several semiconductor companies in order to close a major gap in the mask manufacturing infrastructure and the challenges to be met.

Serendipitous EUV sources detected during the first year of the Extreme Ultraviolet Explorer right angle program

NASA Technical Reports Server (NTRS)

Mcdonald, K.; Craig, N.; Sirk, M. M.; Drake, J. J.; Fruscione, A.; Vallerga, J. V.; Malina, R. F.

1994-01-01

We report the detection of 114 extreme ultraviolet (EUV; 58 - 740 A) sources, of which 99 are new serendipitous sources, based on observations made with the imaging telescopes on board the Extreme Ultraviolet Explorer (EUVE) during the Right Angle Program (RAP). These data were obtained using the survey scanners and the Deep Survey instrument during the first year of the spectroscopic guest observer phase of the mission, from January 1993 to January 1994. The data set consists of 162 discrete pointings whose exposure times are typically two orders of magnitude longer than the average exposure times during the EUVE all-sky survey. Based on these results, we can expect that EUVE will serendipitously detect approximately 100 new EUV sources per year, or about one new EUV source per 10 sq deg, during the guest observer phase of the EUVE mission. New EUVE sources of note include one B star and three extragalactic objects. The B star (HR 2875, EUVE J0729 - 38.7) is detected in both the Lexan/B (approximately 100 A) and Al/Ti/C (approximately 200 A) bandpasses, and the detection is shown not to be a result of UV leaks. We suggest that we are detecting EUV and/or soft x rays from a companion to the B star. Three sources, EUVE J2132+10.1, EUVE J2343-14.9, and EUVE J2359-30.6 are identified as the active galactic nuclei MKN 1513, MS2340.9-1511, and 1H2354-315, respectively.

The novel solution for negative impact of out-of-band and outgassing by top coat materials in EUVL

NASA Astrophysics Data System (ADS)

Fujitani, Noriaki; Sakamoto, Rikimaru; Endo, Takafumi; Onishi, Ryuji; Nishita, Tokio; Yaguchi, Hiroaki; Ho, Bang-Ching

2013-03-01

EUV lithography (EUVL) is the most promising candidate of next generation technology for hp20nm node device manufacturing and beyond. However, the power of light source, masks and photo resists are the most critical issues for driving the EUVL. Especially, concerning about deterioration of the patterning performance by Out-of-Band (OoB) light existing in the EUV light, and contamination problem of exposure tool due to the resist outgassing are the key issues which have to be resolved in the material view point toward the high volume manufacturing by EUVL. This paper proposes the solution for these critical issues by applying the top coat material. The key characteristics for top coat material are the protection of the OoB effect, the prevention of the outgassing from resist as a barrier layer and enhancement of photo resist performance, like resist profile and process window. This paper describes the material design and performance. The optical property needs having the high absorbance of DUV light in OoB range and high transmittance for 13.5nm wavelength. Outgassing barrier property needs high broking property against non contamination chemical species from photo resist outgassing. The study of TOF-SIMS analysis indicates how much the polymer chemistry can impact for outgassing barrier property. The dependency of material design and lithography performance is also discussed.

Quality control of EUVE databases

NASA Technical Reports Server (NTRS)

John, L. M.; Drake, J.

1992-01-01

The publicly accessible databases for the Extreme Ultraviolet Explorer include: the EUVE Archive mailserver; the CEA ftp site; the EUVE Guest Observer Mailserver; and the Astronomical Data System node. The EUVE Performance Assurance team is responsible for verifying that these public EUVE databases are working properly, and that the public availability of EUVE data contained therein does not infringe any data rights which may have been assigned. In this poster, we describe the Quality Assurance (QA) procedures we have developed from the approach of QA as a service organization, thus reflecting the overall EUVE philosophy of Quality Assurance integrated into normal operating procedures, rather than imposed as an external, post facto, control mechanism.

Anticipating and controlling mask costs within EDA physical design

NASA Astrophysics Data System (ADS)

Rieger, Michael L.; Mayhew, Jeffrey P.; Melvin, Lawrence S.; Lugg, Robert M.; Beale, Daniel F.

2003-08-01

For low k1 lithography, more aggressive OPC is being applied to critical layers, and the number of mask layers with OPC treatments is growing rapidly. The 130 nm, process node required, on average, 8 layers containing rules- or model-based OPC. The 90 nm node will have 16 OPC layers, of which 14 layers contain aggressive model-based OPC. This escalation of mask pattern complexity, coupled with the predominant use of vector-scan e-beam (VSB) mask writers contributes to the rising costs of advanced mask sets. Writing times for OPC layouts are several times longer than for traditional layouts, making mask exposure the single largest cost component for OPC masks. Lower mask yields, another key factor in higher mask costs, is also aggravated by OPC. Historical mask set costs are plotted below. The initial cost of a 90 nm-node mask set will exceed one million dollars. The relative impact of mask cost on chip depends on how many total wafers are printed with each mask set. For many foundry chips, where unit production is often well below 1000 wafers, mask costs are larger than wafer processing costs. Further increases in NRE may begin to discourage these suppliers' adoption to 90 nm and smaller nodes. In this paper we will outline several alternatives for reducing mask costs by strategically leveraging dimensional margins. Dimensional specifications for a particular masking layer usually are applied uniformly to all features on that layer. As a practical matter, accuracy requirements on different features in the design may vary widely. Take a polysilicon layer, for example: global tolerance specifications for that layer are driven by the transistor-gate requirements; but these parameters over-specify interconnect feature requirements. By identifying features where dimensional accuracy requirements can be reduced, additional margin can be leveraged to reduce OPC complexity. Mask writing time on VSB tools will drop in nearly direct proportion to reduce shot count. By inspecting masks with reference to feature-dependent margins, instead of uniform specifications, mask yield can be effectively increased further reducing delivered mask expense.

High-NA metrology and sensing on Berkeley MET5

NASA Astrophysics Data System (ADS)

Miyakawa, Ryan; Anderson, Chris; Naulleau, Patrick

2017-03-01

In this paper we compare two non-interferometric wavefront sensors suitable for in-situ high-NA EUV optical testing. The first is the AIS sensor, which has been deployed in both inspection and exposure tools. AIS is a compact, optical test that directly measures a wavefront by probing various parts of the imaging optic pupil and measuring localized wavefront curvature. The second is an image-based technique that uses an iterative algorithm based on simulated annealing to reconstruct a wavefront based on matching aerial images through focus. In this technique, customized illumination is used to probe the pupil at specific points to optimize differences in aberration signatures.

Don't kill canaries! Introducing a new test device to assess the electrostatic risk potential to photomasks

NASA Astrophysics Data System (ADS)

Sebald, Thomas

2008-10-01

Electrostatic protection is an issue for all masks, whether during mask production, shipping, storage, handling or inspection and exposure. Up to now, only manual electrostatic field measurements, or expensive and elaborate analyses with Canary reticles have given hints about the risks of pattern damage by ESD events. A new test device is being introduced, which consists of electrostatic field sensors, integrated INSIDE a closed fused quartz housing which has the outside dimensions of a 6 inch mask. This device can be handled and used like a normal 6 inch reticle. It can be handled and processed while recording the electrostatic charges on the chrome patterns created by friction or field induction just as a reticle would "see" during normal processing.

Portable sandblaster cleans small areas

NASA Technical Reports Server (NTRS)

Severin, H. J.

1966-01-01

Portable sandblasting unit rapidly and effectively cleans localized areas on a metal surface. The unit incorporates a bellows enclosure, masking plate, sand container, and used sand accummulator connected to a vacuum system. The bellows is equipped with an inspection window and light for observation of the sanding operation.

Model-based assist feature insertion for sub-40nm memory device

NASA Astrophysics Data System (ADS)

Suh, Sungsoo; Lee, Suk-joo; Choi, Seong-woon; Lee, Sung-Woo; Park, Chan-hoon

2009-04-01

Many issues need to be resolved for a production-worthy model based assist feature insertion flow for single and double exposure patterning process to extend low k1 process at 193 nm immersion technology. Model based assist feature insertion is not trivial to implement either for single and double exposure patterning compared to rule based methods. As shown in Fig. 1, pixel based mask inversion technology in itself has difficulties in mask writing and inspection although it presents as one of key technology to extend single exposure for contact layer. Thus far, inversion technology is tried as a cooptimization of target mask to simultaneously generate optimized main and sub-resolution assists features for a desired process window. Alternatively, its technology can also be used to optimize for a target feature after an assist feature types are inserted in order to simplify the mask complexity. Simplification of inversion mask is one of major issue with applying inversion technology to device development even if a smaller mask feature can be fabricated since the mask writing time is also a major factor. As shown in Figure 2, mask writing time may be a limiting factor in determining whether or not an inversion solution is viable. It can be reasoned that increased number of shot counts relates to increase in margin for inversion methodology. On the other hand, there is a limit on how complex a mask can be in order to be production worthy. There is also source and mask co-optimization which influences the final mask patterns and assist feature sizes and positions for a given target. In this study, we will discuss assist feature insertion methods for sub 40-nm technology.

A Search for EUV Emission from the O4f Star Zeta Puppis

NASA Technical Reports Server (NTRS)

Waldron, Wayne L.; Vallerga, John

1996-01-01

We obtained a 140 ks EUVE observation of the O4f star, zeta Puppis. Because of its low ISM column density and highly ionized stellar wind, a unique EUV window is accessible for viewing between 128 to 140 A, suggesting that this star may he the only O star observable with the EUVE. Although no SW spectrometer wavelength bin had a signal to noise greater than 3, a bin at 136 A had a signal to noise of 2.4. This bin is where models predict the brightest line due to OV emission should occur. We present several EUV line emission models. These models were constrained by fitting the ROSAT PSPC X-ray data and our EUVE data. If the OV emission is real, the best fits to the data suggest that there are discrepancies in our current understanding of EUV/X-ray production mechanisms. In particular, the emission measure of the EUV source is found to be much greater than the total wind emission measure, suggesting that the EUV shock must produce a very large density enhancement. In addition, the location of the EUV and X-ray shocks are found to be separated by approx. 0.3 stellar radii, but the EUV emission region is found to be approx. 400 times larger than the X-ray emission region. We also discuss the implications of a null detection and present relevant upper limits.

Modeling OPC complexity for design for manufacturability

NASA Astrophysics Data System (ADS)

Gupta, Puneet; Kahng, Andrew B.; Muddu, Swamy; Nakagawa, Sam; Park, Chul-Hong

2005-11-01

Increasing design complexity in sub-90nm designs results in increased mask complexity and cost. Resolution enhancement techniques (RET) such as assist feature addition, phase shifting (attenuated PSM) and aggressive optical proximity correction (OPC) help in preserving feature fidelity in silicon but increase mask complexity and cost. Data volume increase with rise in mask complexity is becoming prohibitive for manufacturing. Mask cost is determined by mask write time and mask inspection time, which are directly related to the complexity of features printed on the mask. Aggressive RET increase complexity by adding assist features and by modifying existing features. Passing design intent to OPC has been identified as a solution for reducing mask complexity and cost in several recent works. The goal of design-aware OPC is to relax OPC tolerances of layout features to minimize mask cost, without sacrificing parametric yield. To convey optimal OPC tolerances for manufacturing, design optimization should drive OPC tolerance optimization using models of mask cost for devices and wires. Design optimization should be aware of impact of OPC correction levels on mask cost and performance of the design. This work introduces mask cost characterization (MCC) that quantifies OPC complexity, measured in terms of fracture count of the mask, for different OPC tolerances. MCC with different OPC tolerances is a critical step in linking design and manufacturing. In this paper, we present a MCC methodology that provides models of fracture count of standard cells and wire patterns for use in design optimization. MCC cannot be performed by designers as they do not have access to foundry OPC recipes and RET tools. To build a fracture count model, we perform OPC and fracturing on a limited set of standard cells and wire configurations with all tolerance combinations. Separately, we identify the characteristics of the layout that impact fracture count. Based on the fracture count (FC) data from OPC and mask data preparation runs, we build models of FC as function of OPC tolerances and layout parameters.

The difficult business model for mask equipment makers and mask infrastructure development support from consortia and governments

NASA Astrophysics Data System (ADS)

Hector, Scott

2005-11-01

The extension of optical projection lithography through immersion to patterning features with half pitch <=65 nm is placing greater demands on the mask. Strong resolution enhancement techniques (RETs), such as embedded and alternating phase shift masks and complex model-based optical proximity correction, are required to compensate for diffraction and limited depth of focus (DOF). To fabricate these masks, many new or upgraded tools are required to write patterns, measure feature sizes and placement, inspect for defects, review defect printability and repair defects on these masks. Beyond the significant technical challenges, suppliers of mask fabrication equipment face the challenge of being profitable in the small market for mask equipment while encountering significant R&D expenses to bring new generations of mask fabrication equipment to market. The total available market for patterned masks is estimated to be $2.5B to $2.9B per year. The patterned mask market is about 20% of the market size for lithography equipment and materials. The total available market for mask-making equipment is estimated to be about $800M per year. The largest R&D affordability issue arises for the makers of equipment for fabricating masks where total available sales are typically less than ten units per year. SEMATECH has used discounted cash flow models to predict the affordable R&D while maintaining industry accepted internal rates of return. The results have been compared to estimates of the total R&D cost to bring a new generation of mask equipment to market for various types of tools. The analysis revealed that affordability of the required R&D is a significant problem for many suppliers of mask-making equipment. Consortia such as SEMATECH and Selete have played an important role in cost sharing selected mask equipment and material development projects. Governments in the United States, in Europe and in Japan have also helped equipment suppliers with support for R&D. This paper summarizes the challenging business model for mask equipment suppliers and highlight government support for mask equipment and materials development.

PECULIAR STATIONARY EUV WAVE FRONTS IN THE ERUPTION ON 2011 MAY 11

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chandra, R.; Fulara, A.; Chen, P. F.

We present and interpret the observations of extreme ultraviolet (EUV) waves associated with a filament eruption on 2011 May 11. The filament eruption also produces a small B-class two ribbon flare and a coronal mass ejection. The event is observed by the Solar Dynamic Observatory with high spatio-temporal resolution data recorded by the Atmospheric Imaging Assembly. As the filament erupts, we observe two types of EUV waves (slow and fast) propagating outwards. The faster EUV wave has a propagation velocity of ∼500 km s{sup −1} and the slower EUV wave has an initial velocity of ∼120 km s{sup −1}. Wemore » report, for the first time, that not only does the slower EUV wave stop at a magnetic separatrix to form bright stationary fronts, but also the faster EUV wave transits a magnetic separatrix, leaving another stationary EUV front behind.« less

Extreme Ultraviolet Explorer. Long look at the next window

NASA Technical Reports Server (NTRS)

Maran, Stephen P.

1991-01-01

The Extreme Ultraviolet Explorer (EUVE) will map the entire sky to determine the existence, direction, brightness, and temperature of thousands of objects that are sources of so-called extreme ultraviolet (EUV) radiation. The EUV spectral region is located between the x-ray and ultraviolet regions of the electromagnetic spectrum. From the sky survey by EUVE, astronomers will determine the nature of sources of EUV light in our galaxy, and infer the distribution of interstellar gas for hundreds of light years around the solar system. It is from this gas and the accompanying dust in space that new stars and solar systems are born and to which evolving and dying stars return much of their material in an endless cosmic cycle of birth, death, and rebirth. Besides surveying the sky, astronomers will make detailed studies of selected objects with EUVE to determine their physical properties and chemical compositions. Also, they will learn about the conditions that prevail and the processes at work in stars, planets, and other sources of EUV radiation, maybe even quasars. The EUVE mission and instruments are described. The objects that EUVE will likely find are described.

Monolithic pattern-sensitive detector

DOEpatents

Berger, Kurt W.

2000-01-01

Extreme ultraviolet light (EUV) is detected using a precisely defined reference pattern formed over a shallow junction photodiode. The reference pattern is formed in an EUV absorber preferably comprising nickel or other material having EUV- and other spectral region attenuating characteristics. An EUV-transmissive energy filter is disposed between a passivation oxide layer of the photodiode and the EUV transmissive energy filter. The device is monolithically formed to provide robustness and compactness.

Selected highlights from the Extreme Ultraviolet Explorer

NASA Technical Reports Server (NTRS)

Bowyer, S.; Malina, R. F.

1995-01-01

We present a few scientific highlights from the Extreme Ultraviolet Explorer (EUVE) all-sky and deep surveys, from the EUVE Righ Angle Program, and from the EUVE Guest Observer Program. The First EUVE Source Catalog includes 410 extreme ultraviolet (EUV) sources detected in the initial processing of the EUVE all-sky data. A program of optical identification indicates that counterparts include cool star coronae, flare stars, hot white dwarfs, central stars of planetary nebulae, B star photospheres and winds, an X-ray binary, extragalactic objects (active galactic nuclei, BL Lacertae), solar system objects (Moon, Mars, Io,), supernova remnants, and two novae.

Analytical techniques for mechanistic characterization of EUV photoresists

NASA Astrophysics Data System (ADS)

Grzeskowiak, Steven; Narasimhan, Amrit; Murphy, Michael; Ackerman, Christian; Kaminsky, Jake; Brainard, Robert L.; Denbeaux, Greg

2017-03-01

Extreme ultraviolet (EUV, 13.5 nm) lithography is the prospective technology for high volume manufacturing by the microelectronics industry. Significant strides towards achieving adequate EUV source power and availability have been made recently, but a limited rate of improvement in photoresist performance still delays the implementation of EUV. Many fundamental questions remain to be answered about the exposure mechanisms of even the relatively well understood chemically amplified EUV photoresists. Moreover, several groups around the world are developing revolutionary metal-based resists whose EUV exposure mechanisms are even less understood. Here, we describe several evaluation techniques to help elucidate mechanistic details of EUV exposure mechanisms of chemically amplified and metal-based resists. EUV absorption coefficients are determined experimentally by measuring the transmission through a resist coated on a silicon nitride membrane. Photochemistry can be evaluated by monitoring small outgassing reaction products to provide insight into photoacid generator or metal-based resist reactivity. Spectroscopic techniques such as thin-film Fourier transform infrared (FTIR) spectroscopy can measure the chemical state of a photoresist system pre- and post-EUV exposure. Additionally, electrolysis can be used to study the interaction between photoresist components and low energy electrons. Collectively, these techniques improve our current understanding of photomechanisms for several EUV photoresist systems, which is needed to develop new, better performing materials needed for high volume manufacturing.

Reticle stage based linear dosimeter

DOEpatents

Berger, Kurt W [Livermore, CA

2007-03-27

A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.

Reticle stage based linear dosimeter

DOEpatents

Berger, Kurt W.

2005-06-14

A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.

Identification of optimal mask size parameter for noise filtering in 99mTc-methylene diphosphonate bone scintigraphy images.

PubMed

Pandey, Anil K; Bisht, Chandan S; Sharma, Param D; ArunRaj, Sreedharan Thankarajan; Taywade, Sameer; Patel, Chetan; Bal, Chandrashekhar; Kumar, Rakesh

2017-11-01

Tc-methylene diphosphonate (Tc-MDP) bone scintigraphy images have limited number of counts per pixel. A noise filtering method based on local statistics of the image produces better results than a linear filter. However, the mask size has a significant effect on image quality. In this study, we have identified the optimal mask size that yields a good smooth bone scan image. Forty four bone scan images were processed using mask sizes 3, 5, 7, 9, 11, 13, and 15 pixels. The input and processed images were reviewed in two steps. In the first step, the images were inspected and the mask sizes that produced images with significant loss of clinical details in comparison with the input image were excluded. In the second step, the image quality of the 40 sets of images (each set had input image, and its corresponding three processed images with 3, 5, and 7-pixel masks) was assessed by two nuclear medicine physicians. They selected one good smooth image from each set of images. The image quality was also assessed quantitatively with a line profile. Fisher's exact test was used to find statistically significant differences in image quality processed with 5 and 7-pixel mask at a 5% cut-off. A statistically significant difference was found between the image quality processed with 5 and 7-pixel mask at P=0.00528. The identified optimal mask size to produce a good smooth image was found to be 7 pixels. The best mask size for the John-Sen Lee filter was found to be 7×7 pixels, which yielded Tc-methylene diphosphonate bone scan images with the highest acceptable smoothness.

Surface Inhomogeneities of the White Dwarf in the Binary EUVE J2013+400

NASA Astrophysics Data System (ADS)

Vennes, Stephane

We propose to study the white dwarf in the binary EUVE J2013+400. The object is paired with a dMe star and new extreme ultraviolet (EUV) observations will offer critical insights into the properties of the white dwarf. The binary behaves, in every other aspects, like its siblings EUVE J0720-317 and EUVE J1016-053 and new EUV observations will help establish their class properties; in particular, EUV photometric variations in 0720-317 and 1016-053 over a period of 11 hours and 57 minutes, respectively, are indicative of surface abundance inhomogeneities coupled with the white dwarfs rotation period. These variations and their large photospheric helium abundance are best explained by a diffusion-accretion model in which time-variable accretion and possible coupling to magnetic poles contribute to abundance variations across the surface and possibly as a function of depth. EUV spectroscopy will also enable a study of the helium abundance as a function of depth and a detailed comparison with theoretical diffusion profile.

SMIF capability at Intel Mask Operation improves yield

NASA Astrophysics Data System (ADS)

Dam, Thuc H.; Pekny, Matt; Millino, Jim; Luu, Gibson; Melwani, Nitesh; Venkatramani, Aparna; Tavassoli, Malahat

2003-08-01

At Intel Mask Operations (IMO), Standard Mechanical Interface (SMIF) processing has been employed to reduce environmental particle contamination from manual handling-related activities. SMIF handling entailed the utilization of automated robotic transfers of photoblanks/reticles between SMIF pods, whereas conventional handling utilized manual pick transfers of masks between SMIF pods with intermediate storage in Toppan compacts. The SMIF-enabling units in IMO's process line included: (1) coater, (2) exposure, (3) developer, (4) dry etcher, and (5) inspection. Each unit is equipped with automated I/O port, environmentally enclosed processing chamber, and SMIF pods. Yield metrics were utilized to demonstrate the effectiveness and advantages of SMIF processing compared to manual processing. The areas focused in this paper were blank resist coating, binary front-end reticle processing and 2nd level PSM reticle processing. Results obtained from the investigation showed yield improvements in these areas.

Single-nm resolution approach by applying DDRP and DDRM

NASA Astrophysics Data System (ADS)

Shibayama, Wataru; Shigaki, Shuhei; Takeda, Satoshi; Nakajima, Makoto; Sakamoto, Rikimaru

2017-03-01

EUV lithography has been desired as the leading technology for 1x or single nm half-pitch patterning. However, the source power, masks and resist materials still have critical issues for mass production. Especially in resist materials, RLS trade-off has been the key issue. To overcome this issue, we are suggesting Dry Development Rinse Process (DDRP) and Materials (DDRM) as the pattern collapse mitigation approach. This DDRM can perform not only as pattern collapse free materials for fine pitch, but also as the etching hard mask against bottom layer (spin on carbon : SOC). In this paper, we especially propose new approaches to achieve high resolution around hp1X nm L/S and single nm line patterning. Especially, semi iso 8nm line was successfully achieved with good LWR (2.5nm) and around 3 times aspect ratio. This single nm patterning technique also helped to enhance sensitivity about 33%. On the other hand, pillar patterning thorough CH pattern by applying DDRP also showed high resolution below 20nm pillar CD with good LCDU and high sensitivity. This new DDRP technology can be the promising approach not only for hp1Xnm level patterning but also single nm patterning in N7/N5 and beyond.

Contrast matching of line gratings obtained with NXE3XXX and EUV- interference lithography

NASA Astrophysics Data System (ADS)

Tasdemir, Zuhal; Mochi, Iacopo; Olvera, Karen Garrido; Meeuwissen, Marieke; Yildirim, Oktay; Custers, Rolf; Hoefnagels, Rik; Rispens, Gijsbert; Fallica, Roberto; Vockenhuber, Michaela; Ekinci, Yasin

2017-10-01

Extreme UV lithography (EUVL) has gained considerable attention for several decades as a potential technology for the semiconductor industry and it is now close to being adopted in high-volume manufacturing. At Paul Scherrer Institute (PSI), we have focused our attention on EUV resist performance issues by testing available high-performance EUV resists in the framework of a joint collaboration with ASML. For this purpose, we use the grating-based EUV-IL setup installed at the Swiss Light Source (SLS) at PSI, in which a coherent beam with 13.5 nm wavelength is used to produce a periodic aerial image with virtually 100% contrast and large depth of focus. Interference lithography is a relatively simple technique and it does not require many optical components, therefore the unintended flare is minimized and the aerial image is well-defined sinusoidal pattern. For the collaborative work between PSI and ASML, exposures are being performed on the EUV-IL exposure tool at PSI. For better quantitative comparison to the NXE scanner results, it is targeted to determine the actual NILS of the EUV-IL exposure tool at PSI. Ultimately, any resist-related metrology must be aligned and compared with the performance of EUV scanners. Moreover, EUV-IL is a powerful method for evaluating the resist performance and a resist which performs well with EUV-IL, shows, in general, also good performance with NXE scanners. However, a quantitative prediction of the performance based on EUV-IL measurements has not been possible due to the differences in aerial image formation. In this work, we aim to study the performance of EUV resists with different aerial images. For this purpose, after the real interference pattern exposure, we overlay a flat field exposure to emulate different levels of contrast. Finally, the results are compared with data obtained from EUV scanner. This study will enable not only match the data obtained from EUV- IL at PSI with the performance of NXE scanners, but also a better understanding of resist fundamentals by studying the effects of the aerial image on resist performance by changing the aerial image contrast in a controlled manner using EUV-IL.

Fiber-optic fringe projection with crosstalk reduction by adaptive pattern masking

NASA Astrophysics Data System (ADS)

Matthias, Steffen; Kästner, Markus; Reithmeier, Eduard

2017-02-01

To enable in-process inspection of industrial manufacturing processes, measuring devices need to fulfill time and space constraints, while also being robust to environmental conditions, such as high temperatures and electromagnetic fields. A new fringe projection profilometry system is being developed, which is capable of performing the inspection of filigree tool geometries, e.g. gearing elements with tip radii of 0.2 mm, inside forming machines of the sheet-bulk metal forming process. Compact gradient-index rod lenses with a diameter of 2 mm allow for a compact design of the sensor head, which is connected to a base unit via flexible high-resolution image fibers with a diameter of 1.7 mm. The base unit houses a flexible DMD based LED projector optimized for fiber coupling and a CMOS camera sensor. The system is capable of capturing up to 150 gray-scale patterns per second as well as high dynamic range images from multiple exposures. Owing to fiber crosstalk and light leakage in the image fiber, signal quality suffers especially when capturing 3-D data of technical surfaces with highly varying reflectance or surface angles. An algorithm is presented, which adaptively masks parts of the pattern to reduce these effects via multiple exposures. The masks for valid surface areas are automatically defined according to different parameters from an initial capture, such as intensity and surface gradient. In a second step, the masks are re-projected to projector coordinates using the mathematical model of the system. This approach is capable of reducing both inter-pixel crosstalk and inter-object reflections on concave objects while maintaining measurement durations of less than 5 s.

Patterning techniques for next generation IC's

NASA Astrophysics Data System (ADS)

Balasinski, A.

2007-12-01

Reduction of linear critical dimensions (CDs) beyond 45 nm would require significant increase of the complexity of pattern definition process. In this work, we discuss the key successor methodology to the current optical lithography, the Double Patterning Technique (DPT). We compare the complexity of CAD solutions, fab equipment, and wafer processing with its competitors, such as the nanoimprint (NIL) and the extreme UV (EUV) techniques. We also look ahead to the market availability for the product families enabled using the novel patterning solutions. DPT is often recognized as the most viable next generation lithography as it utilizes the existing equipment and processes and is considered a stop-gap solution before the advanced NIL or EUV equipment is developed. Using design for manufacturability (DfM) rules, DPT can drive the k1 factor down to 0.13. However, it faces a variety of challenges, from new mask overlay strategies, to layout pattern split, novel OPC, increased CD tolerances, new etch techniques, as well as long processing time, all of which compromise its return on investment (RoI). In contrast, it can be claimed e.g., that the RoI is the highest for the NIL but this technology bears significant risk. For all novel patterning techniques, the key questions remain: when and how should they be introduced, what is their long-term potential, when should they be replaced, and by what successor technology. We summarize the unpublished results of several panel discussions on DPT at the recent SPIE/BACUS conferences.

Novel EUV photoresist for sub-7nm node (Conference Presentation)

NASA Astrophysics Data System (ADS)

Furukawa, Tsuyoshi; Naruoka, Takehiko; Nakagawa, Hisashi; Miyata, Hiromu; Shiratani, Motohiro; Hori, Masafumi; Dei, Satoshi; Ayothi, Ramakrishnan; Hishiro, Yoshi; Nagai, Tomoki

2017-04-01

Extreme ultraviolet (EUV) lithography has been recognized as a promising candidate for the manufacturing of semiconductor devices as LS and CH pattern for 7nm node and beyond. EUV lithography is ready for high volume manufacturing stage. For the high volume manufacturing of semiconductor devices, significant improvement of sensitivity and line edge roughness (LWR) and Local CD Uniformity (LCDU) is required for EUV resist. It is well-known that the key challenge for EUV resist is the simultaneous requirement of ultrahigh resolution (R), low line edge roughness (L) and high sensitivity (S). Especially high sensitivity and good roughness is important for EUV lithography high volume manufacturing. We are trying to improve sensitivity and LWR/LCDU from many directions. From material side, we found that both sensitivity and LWR/LCDU are simultaneously improved by controlling acid diffusion length and efficiency of acid generation using novel resin and PAG. And optimizing EUV integration is one of the good solution to improve sensitivity and LWR/LCDU. We are challenging to develop new multi-layer materials to improve sensitivity and LWR/LCDU. Our new multi-layer materials are designed for best performance in EUV lithography system. From process side, we found that sensitivity was substantially improved maintaining LWR applying novel type of chemical amplified resist (CAR) and process. EUV lithography evaluation results obtained for new CAR EUV interference lithography. And also metal containing resist is one possibility to break through sensitivity and LWR trade off. In this paper, we will report the recent progress of sensitivity and LWR/LCDU improvement of JSR novel EUV resist and process.

EUVE and IR observations of the Polars HU Aqr and AR UMa

NASA Astrophysics Data System (ADS)

Howell, S.; Ciardi, D.

1999-12-01

Simultaneous EUVE and ground-based near-infrared J and K observations of the magnetic CV HU Aqr were performed. The observations occurred during a super-high state never before observed in HU Aqr. The average EUVE count-rate was 30-60 times higher than had been measured previously, allowing us to present the first ever EUV spectra of HU Aqr. The near-infrared observations show a corresponding flux increase of 2-3 times over previous J and K observations. However, the near-infrared eclipse minimum during this super-high state are the same as seen in previous observations, indicating that the eclipse in the near-infrared is total. We present a detailed comparison of the EUV and near-infrared emission of HU Aqr as a function of orbital phase and discuss the geometry and physical properties of the high energy and infrared emitting regions. AR UMa is the brightest EUV source yet observed with the EUVE satellite and is also the polar with the largest magnetic field, 250 MG. EUVE observations of the polar AR UMa have allowed, for the first time, EUV time-resolved spectral analysis and radial velocity measurements. We present EUV phase-resolved photometry and spectroscopy and show that the He 304 emission line is not produced on the heated face of the secondary star, but emanates from the inner illuminated regions of the coupling region and accretion stream. We comment on the overall structure of the accretion geometry as well. The authors acknowledge partial support of the research by NASA cooperative agreement NCC5-138 via an EUVE guest Observer mini-grant.

The extreme ultraviolet explorer mission

NASA Technical Reports Server (NTRS)

Malina, R. F.; Bowyer, S.

1988-01-01

The science design goals and engineering implementation for the Extreme Ultraviolet Explorer (EUVE) science payload are discussed. The primary scientific goal of the EUVE payload is to carry out an all-sky survey in the 100- to 900-A band of the spectrum. Another goal of the mission is to demonstrate the use of a scientific platform in near-earth orbit. EUVE data will be used to study the distribution of EUV stars in the neighborhood of the sun and the emission physics responsible for the EUV mission.

The use of computational inspection to identify process window limiting hotspots and predict sub-15nm defects with high capture rate

NASA Astrophysics Data System (ADS)

Ham, Boo-Hyun; Kim, Il-Hwan; Park, Sung-Sik; Yeo, Sun-Young; Kim, Sang-Jin; Park, Dong-Woon; Park, Joon-Soo; Ryu, Chang-Hoon; Son, Bo-Kyeong; Hwang, Kyung-Bae; Shin, Jae-Min; Shin, Jangho; Park, Ki-Yeop; Park, Sean; Liu, Lei; Tien, Ming-Chun; Nachtwein, Angelique; Jochemsen, Marinus; Yan, Philip; Hu, Vincent; Jones, Christopher

2017-03-01

As critical dimensions for advanced two dimensional (2D) DUV patterning continue to shrink, the exact process window becomes increasingly difficult to determine. The defect size criteria shrink with the patterning critical dimensions and are well below the resolution of current optical inspection tools. As a result, it is more challenging for traditional bright field inspection tools to accurately discover the hotspots that define the process window. In this study, we use a novel computational inspection method to identify the depth-of-focus limiting features of a 10 nm node mask with 2D metal structures (single exposure) and compare the results to those obtained with a traditional process windows qualification (PWQ) method based on utilizing a focus modulated wafer and bright field inspection (BFI) to detect hotspot defects. The method is extended to litho-etch litho-etch (LELE) on a different test vehicle to show that overlay related bridging hotspots also can be identified.

Characterization of extreme ultraviolet laser ablation mass spectrometry for actinide trace analysis and nanoscale isotopic imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, Tyler; Kuznetsov, Ilya; Willingham, David

The purpose of this research was to characterize Extreme Ultraviolet Time-of-Flight (EUV TOF) Laser Ablation Mass Spectrometry for high spatial resolution elemental and isotopic analysis. We compare EUV TOF results with Secondary Ionization Mass Spectrometry (SIMS) to orient the EUV TOF method within the overall field of analytical mass spectrometry. Using the well-characterized NIST 61x glasses, we show that the EUV ionization approach produces relatively few molecular ion interferences in comparison to TOF SIMS. We demonstrate that the ratio of element ion to element oxide ion is adjustable with EUV laser pulse energy and that the EUV TOF instrument hasmore » a sample utilization efficiency of 0.014%. The EUV TOF system also achieves a lateral resolution of 80 nm and we demonstrate this lateral resolution with isotopic imaging of closely spaced particles or uranium isotopic standard materials.« less

EUV Cross-Calibration Strategies for the GOES-R SUVI

NASA Astrophysics Data System (ADS)

Darnel, Jonathan; Seaton, Daniel

2016-10-01

The challenges of maintaining calibration for solar EUV instrumentation is well-known. The lack of standard calibration sources and the fact that most solar EUV telescopes are incapable of utilizing bright astronomical EUV sources for calibration make knowledge of instrument performance quite difficult. In the recent past, calibration rocket underflights have helped establish a calibration baseline. The EVE instrument on SDO for a time provided well-calibrated, high spectral resolution solar spectra for a broad range of the EUV, but has suffered a loss of coverage at the shorter wavelengths. NOAA's Solar UltraViolet Imager (SUVI), a solar EUV imager with similarities to SDO/AIA, will provide solar imagery over nearly an entire solar cycle. In order to maintain the scientific value of the SUVI's dataset, novel approaches to calibration are necessary. Here we demonstrate a suite of methods to cross-calibrate SUVI against other solar EUV instruments through the use of proxy solar spectra.

Objective for EUV microscopy, EUV lithography, and x-ray imaging

DOEpatents

Bitter, Manfred; Hill, Kenneth W.; Efthimion, Philip

2016-05-03

Disclosed is an imaging apparatus for EUV spectroscopy, EUV microscopy, EUV lithography, and x-ray imaging. This new imaging apparatus could, in particular, make significant contributions to EUV lithography at wavelengths in the range from 10 to 15 nm, which is presently being developed for the manufacturing of the next-generation integrated circuits. The disclosure provides a novel adjustable imaging apparatus that allows for the production of stigmatic images in x-ray imaging, EUV imaging, and EUVL. The imaging apparatus of the present invention incorporates additional properties compared to previously described objectives. The use of a pair of spherical reflectors containing a concave and convex arrangement has been applied to a EUV imaging system to allow for the image and optics to all be placed on the same side of a vacuum chamber. Additionally, the two spherical reflector segments previously described have been replaced by two full spheres or, more precisely, two spherical annuli, so that the total photon throughput is largely increased. Finally, the range of permissible Bragg angles and possible magnifications of the objective has been largely increased.

Initial results from the extreme ultraviolet explorer

NASA Technical Reports Server (NTRS)

Bowyer, S.; Malina, R. F.

1993-01-01

Data obtained during the first five months of calibration and science operation of the Extreme Ultraviolet Explorer (EUVE) are presented. Spectra of an extragalactic object were obtained; the object is detectable to wavelenghts longer than 100 A, demonstrating that extragalactic EUV astronomy is possible. Spectra of a hot white dwarf, and a late-type star in quiescence and flaring are shown as examples of the type of spectrographic data obtainable with EUVE. Other objects for which broad band photometric mode data have been obtained and analyzed include an RS CVn star and several late-type stars. The backgrounds in the EUVE detectors are quite low and the character of the diffuse astronomical EUV background has been investigated using these very low rates. Evidence is presented showing that, contrary to previously published reports, EUVE is about three times more sensitive than the English Wide Field Camera in the short wavelength bandpass covered by both instruments. Only limited information has been extracted from the longer bandpasses coered only by EUVE. Nonetheless, the brightest EUV source in the sky, a B star, has been discovered and is detected only in these longer bandpasses.

Surface roughness control by extreme ultraviolet (EUV) radiation

NASA Astrophysics Data System (ADS)

Ahad, Inam Ul; Obeidi, Muhannad Ahmed; Budner, Bogusław; Bartnik, Andrzej; Fiedorowicz, Henryk; Brabazon, Dermot

2017-10-01

Surface roughness control of polymeric materials is often desirable in various biomedical engineering applications related to biocompatibility control, separation science and surface wettability control. In this study, Polyethylene terephthalate (PET) polymer films were irradiated with Extreme ultraviolet (EUV) photons in nitrogen environment and investigations were performed on surface roughness modification via EUV exposure. The samples were irradiated at 3 mm and 4 mm distance from the focal spot to investigate the effect of EUV fluence on topography. The topography of the EUV treated PET samples were studied by AFM. The detailed scanning was also performed on the sample irradiated at 3 mm. It was observed that the average surface roughness of PET samples was increased from 9 nm (pristine sample) to 280 nm and 253 nm for EUV irradiated samples. Detailed AFM studies confirmed the presence of 1.8 mm wide period U-shaped channels in EUV exposed PET samples. The walls of the channels were having FWHM of about 0.4 mm. The channels were created due to translatory movements of the sample in horizontal and transverse directions during the EUV exposure. The increased surface roughness is useful for many applications. The nanoscale channels fabricated by EUV exposure could be interesting for microfluidic applications based on lab-on-a-chip (LOC) devices.

EUVE GO Survey: High Levels of User Satisfaction

NASA Astrophysics Data System (ADS)

Stroozas, B. A.

2000-12-01

This paper describes the results of a detailed customer survey of Guest Observers (GOs) for NASA's Extreme Ultraviolet Explorer (EUVE) astronomy satellite observatory. The purpose of the research survey was to (1) measure the levels of GO customer satisfaction with respect to EUVE observing services, and (2) compare the observing experiences of EUVE GOs with their experiences using other satellite observatories. This survey was conducted as a business research project -- part of the author's graduate work as an MBA candidate. A total sample of 38 respondents, from a working population of 101 "active" EUVE GOs, participated in this survey. The results, which provided a profile of the "typical" EUVE GO, showed in a statistically significant fashion that these GOs were more than satisfied with the available EUVE observing services. In fact, the sample GOs generally rated their EUVE observing experiences to be better than average as compared to their experiences as GOs on other missions. These relatively high satisfaction results are particularly pleasing to the EUVE Project which, given its significantly reduced staffing environment at U.C. Berkeley, has continued to do more with less. This paper outlines the overall survey process: the relevant background and previous research, the survey design and methodology, and the final results and their interpretation. The paper also points out some general limitations and weaknesses of the study, along with some recommended actions for the EUVE Project and for NASA in general. This work was funded by NASA/UCB Cooperative Agreement NCC5-138.

Temporal variations of solar EUV, UV, and 10,830-A radiations

NASA Technical Reports Server (NTRS)

Donnelly, R. F.; Hinteregger, H. E.; Heath, D. F.

1986-01-01

The temporal characteristics of the full-disk chromospheric EUV fluxes agree well with those of the ground-based measurements of the chromospheric He I absorption line at 10,830 A and differ systematically from those of the coronal EUV and 10.7-cm flux. The ratio of the flux increase during the rise of solar cycle 21 to that during solar rotation variations is uniformly high for the chromospheric EUV and corroborating 10,830-A fluxes, highest for the transition region and 'cool' coronal EUV fluxes (T less than 2 x 10 to the 6th K), and lowest for the 'hot' coronal EUV and 10.7-cm flux. The rise and decay rates of episodes of major activity progress from those for the hot coronal EUV lines and the 10.7-cm flux to slower values for the chromospheric H Lyman alpha line, 10,830-A line, and photospheric 2050-A UV flux. It is suggested that active region remnants contribute significantly to the solar cycle increase and during the decay of episodes of major activity. The ratio of power in 13-day periodicity to that for 27 days in high (1/3) for the photospheric UV flux, medium (1/6) for the chromospheric EUV and 10,830-A fluxes, and small to negligible for the hot coronal EUV fluxes. These ratios are used to estimate the dependence of active region emission on the solar central meridian distance for chromospheric and coronal EUV flux.

Fundamentals of EUV resist-inorganic hardmask interactions

NASA Astrophysics Data System (ADS)

Goldfarb, Dario L.; Glodde, Martin; De Silva, Anuja; Sheshadri, Indira; Felix, Nelson M.; Lionti, Krystelle; Magbitang, Teddie

2017-03-01

High resolution Extreme Ultraviolet (EUV) patterning is currently limited by EUV resist thickness and pattern collapse, thus impacting the faithful image transfer into the underlying stack. Such limitation requires the investigation of improved hardmasks (HMs) as etch transfer layers for EUV patterning. Ultrathin (<5nm) inorganic HMs can provide higher etch selectivity, lower post-etch LWR, decreased defectivity and wet strippability compared to spin-on hybrid HMs (e.g., SiARC), however such novel layers can induce resist adhesion failure and resist residue. Therefore, a fundamental understanding of EUV resist-inorganic HM interactions is needed in order to optimize the EUV resist interfacial behavior. In this paper, novel materials and processing techniques are introduced to characterize and improve the EUV resist-inorganic HM interface. HM surface interactions with specific EUV resist components are evaluated for open-source experimental resist formulations dissected into its individual additives using EUV contrast curves as an effective characterization method to determine post-development residue formation. Separately, an alternative adhesion promoter platform specifically tailored for a selected ultrathin inorganic HM based on amorphous silicon (aSi) is presented and the mitigation of resist delamination is exemplified for the cases of positive-tone and negative-tone development (PTD, NTD). Additionally, original wafer priming hardware for the deposition of such novel adhesion promoters is unveiled. The lessons learned in this work can be directly applied to the engineering of EUV resist materials and processes specifically designed to work on such novel HMs.

Extreme ultraviolet (EUV) solar spectral irradiance (SSI) for ionospheric application - history and contemporary state-of-art

NASA Astrophysics Data System (ADS)

Schmidtke, G.; Jacobi, Ch.; Nikutowski, B.; Erhardt, Ch.

2014-11-01

After a historical survey of space related EUV measurements in Germany and the role of Karl Rawer in pursuing this work, we describe present developments in EUV spectroscopy and provide a brief outlook on future activities. The group of Karl Rawer has performed the first scientific space project in Western Europe on 19th October 1954. Then it was decided to include the field of solar EUV spectroscopy in ionospheric investigations. Starting in 1957 an intensified development of instrumentation was going on to explore solar EUV radiation, atmospheric airglow and auroral emissions until the institute had to stop space activities in the early nineteen-eighties. EUV spectroscopy was continued outside of the institute during eight years. This area of work was supported again by the institute developing the Auto-Calibrating Spectrometers (SolACES) for a mission on the International Space Station (ISS). After more than six years in space the instrument is still in operation. Meanwhile the work on the primary task also to validate EUV data available from other space missions has made good progress. The first results of validating those data and combine them into one set of EUV solar spectral irradiance are very promising. It will be recommended for using it by the science and application community. Moreover, a new low-cost type of an EUV spectrometer is presented for monitoring the solar EUV radiation. It shall be further developed for providing EUV-TEC data to be applied in ionospheric models replacing the Covington index F10.7. Applying these data for example in the GNSS signal evaluation a more accurate determination of GNSS receiver positions is expected for correcting the propagation delays of navigation signals traveling through the ionosphere from space to earth. - Latest results in the field of solar EUV spectroscopy are discussed, too.

Scanner qualification with IntenCD based reticle error correction

NASA Astrophysics Data System (ADS)

Elblinger, Yair; Finders, Jo; Demarteau, Marcel; Wismans, Onno; Minnaert Janssen, Ingrid; Duray, Frank; Ben Yishai, Michael; Mangan, Shmoolik; Cohen, Yaron; Parizat, Ziv; Attal, Shay; Polonsky, Netanel; Englard, Ilan

2010-03-01

Scanner introduction into the fab production environment is a challenging task. An efficient evaluation of scanner performance matrices during factory acceptance test (FAT) and later on during site acceptance test (SAT) is crucial for minimizing the cycle time for pre and post production-start activities. If done effectively, the matrices of base line performance established during the SAT are used as a reference for scanner performance and fleet matching monitoring and maintenance in the fab environment. Key elements which can influence the cycle time of the SAT, FAT and maintenance cycles are the imaging, process and mask characterizations involved with those cycles. Discrete mask measurement techniques are currently in use to create across-mask CDU maps. By subtracting these maps from their final wafer measurement CDU map counterparts, it is possible to assess the real scanner induced printed errors within certain limitations. The current discrete measurement methods are time consuming and some techniques also overlook mask based effects other than line width variations, such as transmission and phase variations, all of which influence the final printed CD variability. Applied Materials Aera2TM mask inspection tool with IntenCDTM technology can scan the mask at high speed, offer full mask coverage and accurate assessment of all masks induced source of errors simultaneously, making it beneficial for scanner qualifications and performance monitoring. In this paper we report on a study that was done to improve a scanner introduction and qualification process using the IntenCD application to map the mask induced CD non uniformity. We will present the results of six scanners in production and discuss the benefits of the new method.

Development of a EUV Test Facility at the Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

West, Edward; Pavelitz, Steve; Kobayashi, Ken; Robinson, Brian; Cirtain, Johnathan; Gaskin, Jessica; Winebarger, Amy

2011-01-01

This paper will describe a new EUV test facility that is being developed at the Marshall Space Flight Center (MSFC) to test EUV telescopes. Two flight programs, HiC - high resolution coronal imager (sounding rocket) and SUVI - Solar Ultraviolet Imager (GOES-R), set the requirements for this new facility. This paper will discuss those requirements, the EUV source characteristics, the wavelength resolution that is expected and the vacuum chambers (Stray Light Facility, Xray Calibration Facility and the EUV test chamber) where this facility will be used.

Design and progress in the fabrication of an EUV micro exposure tool optics for PREUVE

NASA Astrophysics Data System (ADS)

Geyl, Roland; Tanne, Jean-Francois

2001-12-01

SAGEM, through its REOSC product line, is participating since November 1999 to PREUVE, the French EUV initiative, and work within this program especially in the field of EUV illumination and projection optics. After a short description of the PREUVE main lines of activity, we will detail our contributions to this program and work progress. This is mainly focused on basic EUV optics fabrication technology in order to ensure the fabrication of the entire optics assembly of an EUV micro exposure tool.

78 FR 23110 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-18

... that during a test of the oxygen system, an operator found that the passenger oxygen masks did not properly flow oxygen, and that a loud noise occurred in the overhead area, which was caused by the flex... airplanes, performing a detailed inspection of certain areas of the airplane oxygen system to ensure...

EUV laser produced and induced plasmas for nanolithography

NASA Astrophysics Data System (ADS)

Sizyuk, Tatyana; Hassanein, Ahmed

2017-10-01

EUV produced plasma sources are being extensively studied for the development of new technology for computer chips production. Challenging tasks include optimization of EUV source efficiency, producing powerful source in 2 percentage bandwidth around 13.5 nm for high volume manufacture (HVM), and increasing the lifetime of collecting optics. Mass-limited targets, such as small droplet, allow to reduce contamination of chamber environment and mirror surface damage. However, reducing droplet size limits EUV power output. Our analysis showed the requirement for the target parameters and chamber conditions to achieve 500 W EUV output for HVM. The HEIGHTS package was used for the simulations of laser produced plasma evolution starting from laser interaction with solid target, development and expansion of vapor/plasma plume with accurate optical data calculation, especially in narrow EUV region. Detailed 3D modeling of mix environment including evolution and interplay of plasma produced by lasers from Sn target and plasma produced by in-band and out-of-band EUV radiation in ambient gas, used for the collecting optics protection and cleaning, allowed predicting conditions in entire LPP system. Effect of these conditions on EUV photon absorption and collection was analyzed. This work is supported by the National Science Foundation, PIRE project.

Extreme ultraviolet spectroscopy diagnostics of low-temperature plasmas based on a sliced multilayer grating and glass capillary optics.

PubMed

Kantsyrev, V L; Safronova, A S; Williamson, K M; Wilcox, P; Ouart, N D; Yilmaz, M F; Struve, K W; Voronov, D L; Feshchenko, R M; Artyukov, I A; Vinogradov, A V

2008-10-01

New extreme ultraviolet (EUV) spectroscopic diagnostics of relatively low-temperature plasmas based on the application of an EUV spectrometer and fast EUV diodes combined with glass capillary optics is described. An advanced high resolution dispersive element sliced multilayer grating was used in the compact EUV spectrometer. For monitoring of the time history of radiation, filtered fast EUV diodes were used in the same spectral region (>13 nm) as the EUV spectrometer. The radiation from the plasma was captured by using a single inexpensive glass capillary that was transported onto the spectrometer entrance slit and EUV diode. The use of glass capillary optics allowed placement of the spectrometer and diodes behind the thick radiation shield outside the direction of a possible hard x-ray radiation beam and debris from the plasma source. The results of the testing and application of this diagnostic for a compact laser plasma source are presented. Examples of modeling with parameters of plasmas are discussed.

Mechanisms of EUV exposure: electrons and holes

NASA Astrophysics Data System (ADS)

Narasimhan, Amrit; Grzeskowiak, Steven; Ackerman, Christian; Flynn, Tracy; Denbeaux, Greg; Brainard, Robert L.

2017-03-01

In extreme ultraviolet (EUV) lithography, 92 eV photons are used to expose photoresists. Current EUV photoresists are composed of photoacid generators (PAGs) in polymer matrices. Secondary electrons (2 - 80 eV) created in resists during EUV exposure play large role in acid-production. There are several proposed mechanisms for electron-resist interactions: internal excitation, electron trapping, and hole-initiated chemistry. Here, we will address two central questions in EUV resist research: (1) How many electrons are generated per EUV photon absorption? (2) By which mechanisms do these electrons interact and react with molecules in the resist? We will use this framework to evaluate the contributions of electron trapping and hole initiated chemistry to acid production in chemically amplified photoresists, with specific emphasis on the interdependence of these mechanisms. We will show measurements of acid yield from direct bulk electrolysis of PAGs and EUV exposures of PAGs in phenolic and nonphenolic polymers to narrow down the mechanistic possibilities in chemically amplified resists.

Solar EUV irradiance for space weather applications

NASA Astrophysics Data System (ADS)

Viereck, R. A.

2015-12-01

Solar EUV irradiance is an important driver of space weather models. Large changes in EUV and x-ray irradiances create large variability in the ionosphere and thermosphere. Proxies such as the F10.7 cm radio flux, have provided reasonable estimates of the EUV flux but as the space weather models become more accurate and the demands of the customers become more stringent, proxies are no longer adequate. Furthermore, proxies are often provided only on a daily basis and shorter time scales are becoming important. Also, there is a growing need for multi-day forecasts of solar EUV irradiance to drive space weather forecast models. In this presentation we will describe the needs and requirements for solar EUV irradiance information from the space weather modeler's perspective. We will then translate these requirements into solar observational requirements such as spectral resolution and irradiance accuracy. We will also describe the activities at NOAA to provide long-term solar EUV irradiance observations and derived products that are needed for real-time space weather modeling.

First environmental data from the EUV engineering test stand

NASA Astrophysics Data System (ADS)

Klebanoff, Leonard E.; Malinowski, Michael E.; Grunow, Philip A.; Clift, W. Miles; Steinhaus, Chip; Leung, Alvin H.; Haney, Steven J.

2001-08-01

The first environmental data from the Engineering Test Stand (ETS) has been collected. Excellent control of high-mass hydrocarbons has been observed. This control is a result of extensive outgas testing of components and materials, vacuum compatible design of the ETS, careful cleaning of parts and pre-baking of cables and sub assemblies where possible, and clean assembly procedures. As a result of the hydrocarbon control, the residual ETS vacuum environment is rich in water vapor. Analysis of witness plate data indicates that the ETS environment does not pose a contamination risk to the optics in the absence of EUV irradiation. However, with EUV exposure, the water rich environment can lead to EUV- induced water oxidation of the Si-terminated Mo/Si optics. Added ethanol can prevent optic oxidation, allowing carbon growth via EUV cracking of low-level residual hydrocarbons to occur. The EUV environmental issues are understood, mitigation approaches have been validated, and EUV optic contamination appears to be manageable.

Molecular dynamics and dynamic Monte-Carlo simulation of irradiation damage with focused ion beams

NASA Astrophysics Data System (ADS)

Ohya, Kaoru

2017-03-01

The focused ion beam (FIB) has become an important tool for micro- and nanostructuring of samples such as milling, deposition and imaging. However, this leads to damage of the surface on the nanometer scale from implanted projectile ions and recoiled material atoms. It is therefore important to investigate each kind of damage quantitatively. We present a dynamic Monte-Carlo (MC) simulation code to simulate the morphological and compositional changes of a multilayered sample under ion irradiation and a molecular dynamics (MD) simulation code to simulate dose-dependent changes in the backscattering-ion (BSI)/secondary-electron (SE) yields of a crystalline sample. Recent progress in the codes for research to simulate the surface morphology and Mo/Si layers intermixing in an EUV lithography mask irradiated with FIBs, and the crystalline orientation effect on BSI and SE yields relating to the channeling contrast in scanning ion microscopes, is also presented.

Critical illumination condenser for x-ray lithography

DOEpatents

Cohen, S.J.; Seppala, L.G.

1998-04-07

A critical illumination condenser system is disclosed, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 {micro}m source and requires a magnification of 26. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth. 6 figs.

Critical illumination condenser for x-ray lithography

DOEpatents

Cohen, Simon J.; Seppala, Lynn G.

1998-01-01

A critical illumination condenser system, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 .mu.m source and requires a magnification of 26.times.. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth.

High numerical aperture ring field projection system for extreme ultraviolet lithography

DOEpatents

Hudyma, Russell

2001-01-01

An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 12.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 .mu.m. Each of the six reflecting surfaces has an aspheric departure of less than 16.0 .mu.m.

High numerical aperture ring field projection system for extreme ultraviolet lithography

DOEpatents

Hudyma, Russell

2000-01-01

An all-refelctive optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle less than substantially 12.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 .mu.m. Each of the six refelecting surfaces has an aspheric departure of less than 16.0 .mu.m.

High numerical aperture ring field projection system for extreme ultraviolet lithography

DOEpatents

Hudyma, Russell; Shafer, David R.

2001-01-01

An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first convex mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receive a chief ray at an incidence angle of less than substantially 9.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 14.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Each of the six reflecting surfaces has an aspheric departure of less than substantially 16 .mu.m.

High numerical aperture ring field projection system for extreme ultraviolet lithography

DOEpatents

Hudyma, Russell; Shafer, David

2001-01-01

An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first convex mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 9.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 14.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Each of the six reflecting surfaces has an aspheric departure of less than substantially 16 .mu.m.

Improved mask-based CD uniformity for gridded-design-rule lithography

NASA Astrophysics Data System (ADS)

Faivishevsky, Lev; Khristo, Sergey; Sagiv, Amir; Mangan, Shmoolik

2009-03-01

The difficulties encountered during lithography of state-of-the-art 2D patterns are formidable, and originate from the fact that deep sub-wavelength features are being printed. This results in a practical limit of k1 >=0.4 as well as a multitude of complex restrictive design rules, in order to mitigate or minimize lithographic hot spots. An alternative approach, that is gradually attracting the lithographic community's attention, restricts the design of critical layers to straight, dense lines (a 1D grid), that can be relatively easily printed using current lithographic technology. This is then followed by subsequent, less critical trimming stages to obtain circuit functionality. Thus, the 1D gridded approach allows hotspot-free, proximity-effect free lithography of ultra low- k1 features. These advantages must be supported by a stable CD control mechanism. One of the overriding parameters impacting CDU performance is photo mask quality. Previous publications have demonstrated that IntenCDTM - a novel, mask-based CDU mapping technology running on Applied Materials' Aera2TM aerial imaging mask inspection tool - is ideally fit for detecting mask-based CDU issues in 1D (L&S) patterned masks for memory production. Owing to the aerial nature of image formation, IntenCD directly probes the CD as it is printed on the wafer. In this paper we suggest that IntenCD is naturally fit for detecting mask-based CDU issues in 1D GDR masks. We then study a novel method of recovering and quantifying the physical source of printed CDU, using a novel implementation of the IntenCD technology. We demonstrate that additional, simple measurements, which can be readily performed on board the Aera2TM platform with minimal throughput penalty, may complement IntenCD and allow a robust estimation of the specific nature and strength of mask error source, such as pattern width variation or phase variation, which leads to CDU issues on the printed wafer. We finally discuss the roles played by IntenCD in advanced GDR mask production, starting with tight control over mask production process, continuing to mask qualification at mask shop and ending at in-line wafer CDU correction in fabs.

Discovery of Strong EUV-induced Balmer Emission in the New WD+dM Binary EUVE J2013+40.0 (RE 2013+400)

NASA Astrophysics Data System (ADS)

Thorstensen, J. R.; Vennes, S.

1993-12-01

The binary system EUVE J2013+40.0 (= RE 2013+400) was discovered in the EUV-selected sample of white dwarfs identified in the course of the ROSAT Wide Field Camera (WFC) all-sky survey (Pounds et al. 1993, MNRAS, 260, 77). The intense extreme ultraviolet (EUV) emission from the hot white dwarf (DAO type) was also detected in the course of the Extreme Ultraviolet Explorer (EUVE) all-sky survey (Bowyer et al. 1993, ApJ, submitted), and the subsequent optical identification campaign suggested the association of EUVE J2013+40.0 with the Feige 24 class of binary systems (see Vennes & Thorstensen, these proceedings). Such systems consist of a hot H-rich white dwarf (DA/DAO) and a red dwarf companion (dM) and are characterized by strong, narrow, variable Balmer emission. We obtained spectroscopy with 4 Angstroms resolution at the Michigan-Dartmouth-MIT Hiltner 2.4 m, covering the Hα and Hβ range. The Hα emission line velocity and equivalent widths varied with a period of 0.708 +/- 0.003 d; the velocity semiamplitude is 89 +/- 3 km s(-1) . The emission equivalent width reaches maximum strength 0.251 +/- 0.007 cycle after maximum emission-line velocity, that is, when the emission source reaches superior conjunction. This is just as expected if the emission arises from reprocessing of the EUV radiation incident upon the face of the dM star facing the white dwarf, as proposed for Feige 24 by Thorstensen et al. (1978, ApJ, 223, 260). EUVE J2013+40.0 is one of a handful of WD+dM binary systems in which the illumination effect is observed with unambiguous clarity. By comparing Feige 24 and EUVE J2013+40.0, and modelling the white dwarf EUV emission and red dwarf Balmer emission, we constrain the orbital inclinations. Additional spectroscopy of EUVE J2013+40.0 is being scheduled to determine the component masses. These are important input data for the study of the close binary systems which arise from common envelope evolution. This work is supported by a forthcoming NASA Guest Observer grant.

Wafer plane inspection with soft resist thresholding

NASA Astrophysics Data System (ADS)

Hess, Carl; Shi, Rui-fang; Wihl, Mark; Xiong, Yalin; Pang, Song

2008-10-01

Wafer Plane Inspection (WPI) is an inspection mode on the KLA-Tencor TeraScaTM platform that uses the high signalto- noise ratio images from the high numerical aperture microscope, and then models the entire lithographic process to enable defect detection on the wafer plane[1]. This technology meets the needs of some advanced mask manufacturers to identify the lithographically-significant defects while ignoring the other non-lithographically-significant defects. WPI accomplishes this goal by performing defect detection based on a modeled image of how the mask features would actually print in the photoresist. There are several advantages to this approach: (1) the high fidelity of the images provide a sensitivity advantage over competing approaches; (2) the ability to perform defect detection on the wafer plane allows one to only see those defects that have a printing impact on the wafer; (3) the use of modeling on the lithographic portion of the flow enables unprecedented flexibility to support arbitrary illumination profiles, process-window inspection in unit time, and combination modes to find both printing and non-printing defects. WPI is proving to be a valuable addition to the KLA-Tencor detection algorithm suite. The modeling portion of WPI uses a single resist threshold as the final step in the processing. This has been shown to be adequate on several advanced customer layers, but is not ideal for all layers. Actual resist chemistry has complicated processes including acid and base-diffusion and quench that are not consistently well-modeled with a single resist threshold. We have considered the use of an advanced resist model for WPI, but rejected it because the burdensome requirements for the calibration of the model were not practical for reticle inspection. This paper describes an alternative approach that allows for a "soft" resist threshold to be applied that provides a more robust solution for the most challenging processes. This approach is just finishing beta testing with a customer developing advanced node designs.

Energy deposition in ultrathin extreme ultraviolet resist films: extreme ultraviolet photons and keV electrons

NASA Astrophysics Data System (ADS)

Kyser, David F.; Eib, Nicholas K.; Ritchie, Nicholas W. M.

2016-07-01

The absorbed energy density (eV/cm3) deposited by extreme ultraviolet (EUV) photons and electron beam (EB) high-keV electrons is proposed as a metric for characterizing the sensitivity of EUV resist films. Simulations of energy deposition are used to calculate the energy density as a function of the incident aerial flux (EUV: mJ/cm2, EB: μC/cm2). Monte Carlo calculations for electron exposure are utilized, and a Lambert-Beer model for EUV absorption. The ratio of electron flux to photon flux which results in equivalent energy density is calculated for a typical organic chemically amplified resist film and a typical inorganic metal-oxide film. This ratio can be used to screen EUV resist materials with EB measurements and accelerate advances in EUV resist systems.

SAQP and EUV block patterning of BEOL metal layers on IMEC's iN7 platform

NASA Astrophysics Data System (ADS)

Bekaert, Joost; Di Lorenzo, Paolo; Mao, Ming; Decoster, Stefan; Larivière, Stéphane; Franke, Joern-Holger; Blanco Carballo, Victor M.; Kutrzeba Kotowska, Bogumila; Lazzarino, Frederic; Gallagher, Emily; Hendrickx, Eric; Leray, Philippe; Kim, R. Ryoung-han; McIntyre, Greg; Colsters, Paul; Wittebrood, Friso; van Dijk, Joep; Maslow, Mark; Timoshkov, Vadim; Kiers, Ton

2017-03-01

The imec N7 (iN7) platform has been developed to evaluate EUV patterning of advanced logic BEOL layers. Its design is based on a 42 nm first-level metal (M1) pitch, and a 32 nm pitch for the subsequent M2 layer. With these pitches, the iN7 node is an `aggressive' full-scaled N7, corresponding to IDM N7, or foundry N5. Even in a 1D design style, single exposure of the 16 nm half-pitch M2 layer is very challenging for EUV lithography, because of its tight tip-to-tip configurations. Therefore, the industry is considering the hybrid use of ArFi-based SAQP combined with EUV Block as an alternative to EUV single exposure. As a consequence, the EUV Block layer may be one of the first layers to adopt EUV lithography in HVM. In this paper, we report on the imec iN7 SAQP + Block litho performance and process integration, targeting the M2 patterning for a 7.5 track logic design. The Block layer is exposed on an ASML NXE:3300 EUV-scanner at imec, using optimized illumination conditions and state-of-the-art metal-containing negative tone resist (Inpria). Subsequently, the SAQP and block structures are characterized in a morphological study, assessing pattern fidelity and CD/EPE variability. The work is an experimental feasibility study of EUV insertion, for SAQP + Block M2 patterning on an industry-relevant N5 use-case.

EUVS Sounding Rocket Payload

NASA Technical Reports Server (NTRS)

Stern, Alan S.

1996-01-01

During the first half of this year (CY 1996), the EUVS project began preparations of the EUVS payload for the upcoming NASA sounding rocket flight 36.148CL, slated for launch on July 26, 1996 to observe and record a high-resolution (approx. 2 A FWHM) EUV spectrum of the planet Venus. These preparations were designed to improve the spectral resolution and sensitivity performance of the EUVS payload as well as prepare the payload for this upcoming mission. The following is a list of the EUVS project activities that have taken place since the beginning of this CY: (1) Applied a fresh, new SiC optical coating to our existing 2400 groove/mm grating to boost its reflectivity; (2) modified the Ranicon science detector to boost its detective quantum efficiency with the addition of a repeller grid; (3) constructed a new entrance slit plane to achieve 2 A FWHM spectral resolution; (4) prepared and held the Payload Initiation Conference (PIC) with the assigned NASA support team from Wallops Island for the upcoming 36.148CL flight (PIC held on March 8, 1996; see Attachment A); (5) began wavelength calibration activities of EUVS in the laboratory; (6) made arrangements for travel to WSMR to begin integration activities in preparation for the July 1996 launch; (7) paper detailing our previous EUVS Venus mission (NASA flight 36.117CL) published in Icarus (see Attachment B); and (8) continued data analysis of the previous EUVS mission 36.137CL (Spica occultation flight).

Mask_explorer: A tool for exploring brain masks in fMRI group analysis.

PubMed

Gajdoš, Martin; Mikl, Michal; Mareček, Radek

2016-10-01

Functional magnetic resonance imaging (fMRI) studies of the human brain are appearing in increasing numbers, providing interesting information about this complex system. Unique information about healthy and diseased brains is inferred using many types of experiments and analyses. In order to obtain reliable information, it is necessary to conduct consistent experiments with large samples of subjects and to involve statistical methods to confirm or reject any tested hypotheses. Group analysis is performed for all voxels within a group mask, i.e. a common space where all of the involved subjects contribute information. To our knowledge, a user-friendly interface with the ability to visualize subject-specific details in a common analysis space did not yet exist. The purpose of our work is to develop and present such interface. Several pitfalls have to be avoided while preparing fMRI data for group analysis. One such pitfall is spurious non-detection, caused by inferring conclusions in the volume of a group mask that has been corrupted due to a preprocessing failure. We describe a MATLAB toolbox, called the mask_explorer, designed for prevention of this pitfall. The mask_explorer uses a graphical user interface, enables a user-friendly exploration of subject masks and is freely available. It is able to compute subject masks from raw data and create lists of subjects with potentially problematic data. It runs under MATLAB with the widely used SPM toolbox. Moreover, we present several practical examples where the mask_explorer is usefully applied. The mask_explorer is designed to quickly control the quality of the group fMRI analysis volume and to identify specific failures related to preprocessing steps and acquisition. It helps researchers detect subjects with potentially problematic data and consequently enables inspection of the data. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Extreme Ultraviolet Explorer Bright Source List

NASA Technical Reports Server (NTRS)

Malina, Roger F.; Marshall, Herman L.; Antia, Behram; Christian, Carol A.; Dobson, Carl A.; Finley, David S.; Fruscione, Antonella; Girouard, Forrest R.; Hawkins, Isabel; Jelinsky, Patrick

1994-01-01

Initial results from the analysis of the Extreme Ultraviolet Explorer (EUVE) all-sky survey (58-740 A) and deep survey (67-364 A) are presented through the EUVE Bright Source List (BSL). The BSL contains 356 confirmed extreme ultraviolet (EUV) point sources with supporting information, including positions, observed EUV count rates, and the identification of possible optical counterparts. One-hundred twenty-six sources have been detected longward of 200 A.

How active was solar cycle 22?

NASA Technical Reports Server (NTRS)

Hoegy, W. R.; Pesnell, W. D.; Woods, T. N.; Rottman, G. J.

1993-01-01

Solar EUV observations from the Langmuir probe on Pioneer Venus Orbiter suggest that at EUV wavelengths solar cycle 22 was more active than solar cycle 21. The Langmuir probe, acting as a photodiode, measured the integrated solar EUV flux over a 13 1/2 year period from January 1979 to June 1992, the longest continuous solar EUV measurement. The Ipe EUV flux correlated very well with the SME measurement of L-alpha during the lifetime of SME and with the UARS SOLSTICE L-alpha from October 1991 to June 1992 when the Ipe measurement ceased. Starting with the peak of solar cycle 21, there was good general agreement of Ipe EUV with the 10.7 cm, Ca K, and He 10830 solar indices, until the onset of solar cycle 22. From 1989 to the start of 1992, the 10.7 cm flux exhibited a broad maximum consisting of two peaks of nearly equal magnitude, whereas Ipe EUV exhibited a strong increase during this time period making the second peak significantly higher than the first. The only solar index that exhibits the same increase in solar activity as Ipe EUV and L-alpha during the cycle 22 peak is the total magnetic flux. The case for high activity during this peak is also supported by the presence of very high solar flare intensity.

Low temperature plasmas induced in SF6 by extreme ultraviolet (EUV) pulses

NASA Astrophysics Data System (ADS)

Bartnik, A.; Skrzeczanowski, W.; Czwartos, J.; Kostecki, J.; Fiedorowicz, H.; Wachulak, P.; Fok, T.

2018-06-01

In this work, a comparative study of extreme ultraviolet (EUV) induced low temperature SF6-based plasmas, created using two different irradiation systems, was performed. Both systems utilized laser-produced plasma (LPP) EUV sources. The essential difference between the systems concerned the formation of the driving EUV beam. The first one contained an efficient ellipsoidal EUV collector allowing for focusing of the EUV radiation at a large distance from the LPP source. The spectrum of focused radiation was limited to the long-wavelength part of the total LPP emission, λ > 8 nm, due to the reflective properties of the collector. The second system did not contain any EUV collector. The gas to be ionized was injected in the vicinity of the LPP, at a distance of the order of 10 mm. In both systems, energies of the driving photons were high enough for dissociative ionization of the SF6 molecules and ionization of atoms or even singly charged ions. Plasmas, created due to these processes, were investigated by spectral measurements in the EUV, ultraviolet (UV), and visible (VIS) spectral ranges. These low temperature plasmas were employed for preliminary experiments concerning surface treatment. The formation of pronounced nanostructures on the silicon surface after plasma treatment was demonstrated.

Influence of cloud fraction and snow cover to the variation of surface UV radiation at King Sejong station, Antarctica

NASA Astrophysics Data System (ADS)

Lee, Yun Gon; Koo, Ja-Ho; Kim, Jhoon

2015-10-01

This study investigated how cloud fraction and snow cover affect the variation of surface ultraviolet (UV) radiation by using surface Erythemal UV (EUV) and Near UV (NUV) observed at the King Sejong Station, Antarctica. First the Radiative Amplification Factor (RAF), the relative change of surface EUV according to the total-column ozone amount, is compared for different cloud fractions and solar zenith angles (SZAs). Generally, all cloudy conditions show that the increase of RAF as SZA becomes larger, showing the larger effects of vertical columnar ozone. For given SZA cases, the EUV transmission through mean cloud layer gradually decreases as cloud fraction increases, but sometimes the maximum of surface EUV appears under partly cloudy conditions. The high surface EUV transmittance under broken cloud conditions seems due to the re-radiation of scattered EUV by cloud particles. NUV transmission through mean cloud layer also decreases as cloud amount increases but the sensitivity to the cloud fraction is larger than EUV. Both EUV and NUV radiations at the surface are also enhanced by the snow cover, and their enhancement becomes higher as SZA increases implying the diurnal variation of surface albedo. This effect of snow cover seems large under the overcast sky because of the stronger interaction between snow surface and cloudy sky.

A volume-limited survey of High Galactic latitude planetary nebulae with the Extrme Ultraviolet Explorer

NASA Technical Reports Server (NTRS)

Fruscione, Antonella; Drake, Jeremy J.; Mcdonald, Kelley; Malina, Roger F.

1995-01-01

We present the results of a complete survey, at extreme-ultraviolet (EUV) wavelengths (58-234 A), of the high Galactic latitude (absolute value of b greater than or = to 20 deg) planetary nebulae (PNs) with at least one determination of the distance within 1 kpc of the Sun. The sample comprises 27 objects observed during the Extreme Ultraviolet Explorer (EUVE) all-sky survey and represents the majority of PN likely to be accessible at EUV wavelengths. Six PNs (NGC 246, NGC 1360, K1-16, LoTr 5, NGC 4361, and NGC 3587) were detected in the shortest EUV band (58-174 A). A seventh PN (NGC 6853), not included in the sample, was also detected during the survey. The emission is consistent in all cases with that of a point source and therefore most probably originates from the PN central star. Accurate EUV count rates or upper limits in the two shorter EUVE bands (centered at approximately 100 and 200 A) are given for all the sources in the sample. NGC 4361 and NGC 3587 are reported here for the first time as sources of EUV radiation. As might be expected, attenuation by the interstellar medium dominates the PN distribution in the EUV sky.

Site Plan Safety Submission for Sampling, Monitoring and Decontamination of Mustard Agent, South Plant, Rocky Mountain Arsenal. Volume 1

DTIC Science & Technology

1988-10-01

agent areas and paints, causing the paint to peel , dissolve, or nel who do the visual inspections or place operations discolor, which may indicate...operated by licensed personnel. (6) Ensure that all downrange personnel have had their protective masks fit checked with amyl acetate ( banana oil). (7

75 FR 47194 - Airworthiness Directives; The Boeing Company Model 737-300, -400, -500, -600, -700, and -800...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-05

... AD requires inspecting to verify the part number of the low-pressure flex-hoses of the crew oxygen system installed under the oxygen mask stowage boxes located within the flight deck, and replacing the... of low-pressure flex-hoses of the crew oxygen system that burned through due to inadvertent...

Automatic classification of blank substrate defects

NASA Astrophysics Data System (ADS)

Boettiger, Tom; Buck, Peter; Paninjath, Sankaranarayanan; Pereira, Mark; Ronald, Rob; Rost, Dan; Samir, Bhamidipati

2014-10-01

Mask preparation stages are crucial in mask manufacturing, since this mask is to later act as a template for considerable number of dies on wafer. Defects on the initial blank substrate, and subsequent cleaned and coated substrates, can have a profound impact on the usability of the finished mask. This emphasizes the need for early and accurate identification of blank substrate defects and the risk they pose to the patterned reticle. While Automatic Defect Classification (ADC) is a well-developed technology for inspection and analysis of defects on patterned wafers and masks in the semiconductors industry, ADC for mask blanks is still in the early stages of adoption and development. Calibre ADC is a powerful analysis tool for fast, accurate, consistent and automatic classification of defects on mask blanks. Accurate, automated classification of mask blanks leads to better usability of blanks by enabling defect avoidance technologies during mask writing. Detailed information on blank defects can help to select appropriate job-decks to be written on the mask by defect avoidance tools [1][4][5]. Smart algorithms separate critical defects from the potentially large number of non-critical defects or false defects detected at various stages during mask blank preparation. Mechanisms used by Calibre ADC to identify and characterize defects include defect location and size, signal polarity (dark, bright) in both transmitted and reflected review images, distinguishing defect signals from background noise in defect images. The Calibre ADC engine then uses a decision tree to translate this information into a defect classification code. Using this automated process improves classification accuracy, repeatability and speed, while avoiding the subjectivity of human judgment compared to the alternative of manual defect classification by trained personnel [2]. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at MP Mask Technology Center (MPMask). The Calibre ADC tool was qualified on production mask blanks against the manual classification. The classification accuracy of ADC is greater than 95% for critical defects with an overall accuracy of 90%. The sensitivity to weak defect signals and locating the defect in the images is a challenge we are resolving. The performance of the tool has been demonstrated on multiple mask types and is ready for deployment in full volume mask manufacturing production flow. Implementation of Calibre ADC is estimated to reduce the misclassification of critical defects by 60-80%.

EUV polarimetry for thin film and surface characterization and EUV phase retarder reflector development.

PubMed

Gaballah, A E H; Nicolosi, P; Ahmed, Nadeem; Jimenez, K; Pettinari, G; Gerardino, A; Zuppella, P

2018-01-01

The knowledge and the manipulation of light polarization state in the vacuum ultraviolet and extreme ultraviolet (EUV) spectral regions play a crucial role from materials science analysis to optical component improvements. In this paper, we present an EUV spectroscopic ellipsometer facility for polarimetry in the 90-160 nm spectral range. A single layer aluminum mirror to be used as a quarter wave retarder has been fully characterized by deriving the optical and structural properties from the amplitude component and phase difference δ measurements. The system can be suitable to investigate the properties of thin films and optical coatings and optics in the EUV region.

``Big Bang" for NASA's Buck: Nearly Three Years of EUVE Mission Operations at UCB

NASA Astrophysics Data System (ADS)

Stroozas, B. A.; Nevitt, R.; McDonald, K. E.; Cullison, J.; Malina, R. F.

1999-12-01

After over seven years in orbit, NASA's Extreme Ultraviolet Explorer (EUVE) satellite continues to perform flawlessly and with no significant loss of science capabilities. EUVE continues to produce important and exciting science results and, with reentry not expected until 2003-2004, many more such discoveries await. In the nearly three years since the outsourcing of EUVE from NASA's Goddard Space Flight Center, the small EUVE operations team at the University of California at Berkeley (UCB) has successfully conducted all aspects of the EUVE mission -- from satellite operations, science and mission planning, and data processing, delivery, and archival, to software support, systems administration, science management, and overall mission direction. This paper discusses UCB's continued focus on automation and streamlining, in all aspects of the Project, as the means to maximize EUVE's overall scientific productivity while minimizing costs. Multitasking, non-traditional work roles, and risk management have led to expanded observing capabilities while achieving significant cost reductions and maintaining the mission's historical 99 return. This work was funded under NASA Cooperative Agreement NCC5-138.

Honing the accuracy of extreme-ultraviolet optical system testing: at-wavelength and visible-light measurements of the ETS Set-2 projection optic

NASA Astrophysics Data System (ADS)

Goldberg, Kenneth A.; Naulleau, Patrick P.; Bokor, Jeffrey; Chapman, Henry N.

2002-07-01

As the quality of optical systems for extreme ultraviolet lithography improves, high-accuracy wavefront metrology for alignment and qualification becomes ever more important. To enable the development of diffraction-limited EUV projection optics, visible-light and EUV interferometries must work in close collaboration. We present a detailed comparison of EUV and visible-light wavefront measurements performed across the field of view of a lithographic-quality EUV projection optical system designed for use in the Engineering Test Stand developed by the Virtual National Laboratory and the EUV Limited Liability Company. The comparisons reveal that the present level of RMS agreement lies in the 0.3-0.4-nm range. Astigmatism is the most significant aberration component for the alignment of this optical system; it is also the dominant term in the discrepancy, and the aberration with the highest measurement uncertainty. With EUV optical systems requiring total wavefront quality in the (lambda) EUV/50 range, and even higher surface-figure quality for the individual mirror elements, improved accuracy through future comparisons, and additional studies, are required.

Efficient extreme-UV-to-extreme-UV conversion by four-wave mixing with intense near-IR pulses in highly charged ion plasmas

NASA Astrophysics Data System (ADS)

Chu, Hsu-hsin; Wang, Jyhpyng

2018-05-01

Nonlinear optics in the extreme-ultraviolet (EUV) has been limited by lack of transparent media and small conversion efficiency. To overcome this problem we explore the advantage of using multiply charged ion plasmas as the interacting media between EUV and intense near-infrared (NIR) pulses. Such media are transparent to EUV and can withstand intense NIR driving pulses without damage. We calculate the third-order nonlinear polarizabilities of Ar2 + and Ar3 + ions for EUV and NIR four-wave mixing by using the well-proven Cowan code and find that the EUV-to-EUV conversion efficiency as high as 26% can be expected for practical experimental configurations using multi-terawatt NIR lasers. Such a high efficiency is possible because the driving pulse intensity can be scaled up to several orders of magnitude higher than in conventional nonlinear media, and the group-velocity and phase mismatch are insignificant at the experimental plasma densities. This effective scheme of wave mixing can be utilized for ultrafast EUV waveform measurement and control as well as wavelength conversion.

Mapper: high throughput maskless lithography

NASA Astrophysics Data System (ADS)

Kuiper, V.; Kampherbeek, B. J.; Wieland, M. J.; de Boer, G.; ten Berge, G. F.; Boers, J.; Jager, R.; van de Peut, T.; Peijster, J. J. M.; Slot, E.; Steenbrink, S. W. H. K.; Teepen, T. F.; van Veen, A. H. V.

2009-01-01

Maskless electron beam lithography, or electron beam direct write, has been around for a long time in the semiconductor industry and was pioneered from the mid-1960s onwards. This technique has been used for mask writing applications as well as device engineering and in some cases chip manufacturing. However because of its relatively low throughput compared to optical lithography, electron beam lithography has never been the mainstream lithography technology. To extend optical lithography double patterning, as a bridging technology, and EUV lithography are currently explored. Irrespective of the technical viability of both approaches, one thing seems clear. They will be expensive [1]. MAPPER Lithography is developing a maskless lithography technology based on massively-parallel electron-beam writing with high speed optical data transport for switching the electron beams. In this way optical columns can be made with a throughput of 10-20 wafers per hour. By clustering several of these columns together high throughputs can be realized in a small footprint. This enables a highly cost-competitive alternative to double patterning and EUV alternatives. In 2007 MAPPER obtained its Proof of Lithography milestone by exposing in its Demonstrator 45 nm half pitch structures with 110 electron beams in parallel, where all the beams where individually switched on and off [2]. In 2008 MAPPER has taken a next step in its development by building several tools. A new platform has been designed and built which contains a 300 mm wafer stage, a wafer handler and an electron beam column with 110 parallel electron beams. This manuscript describes the first patterning results with this 300 mm platform.

Stochastic effects in EUV lithography: random, local CD variability, and printing failures

NASA Astrophysics Data System (ADS)

De Bisschop, Peter

2017-10-01

Stochastic effects in lithography are usually quantified through local CD variability metrics, such as line-width roughness or local CD uniformity (LCDU), and these quantities have been measured and studied intensively, both in EUV and optical lithography. Next to the CD-variability, stochastic effects can also give rise to local, random printing failures, such as missing contacts or microbridges in spaces. When these occur, there often is no (reliable) CD to be measured locally, and then such failures cannot be quantified with the usual CD-measuring techniques. We have developed algorithms to detect such stochastic printing failures in regular line/space (L/S) or contact- or dot-arrays from SEM images, leading to a stochastic failure metric that we call NOK (not OK), which we consider a complementary metric to the CD-variability metrics. This paper will show how both types of metrics can be used to experimentally quantify dependencies of stochastic effects to, e.g., CD, pitch, resist, exposure dose, etc. As it is also important to be able to predict upfront (in the OPC verification stage of a production-mask tape-out) whether certain structures in the layout are likely to have a high sensitivity to stochastic effects, we look into the feasibility of constructing simple predictors, for both stochastic CD-variability and printing failure, that can be calibrated for the process and exposure conditions used and integrated into the standard OPC verification flow. Finally, we briefly discuss the options to reduce stochastic variability and failure, considering the entire patterning ecosystem.

Control of the sidewall angle of an absorber stack using the Faraday cage system for the change of pattern printability in EUVL

NASA Astrophysics Data System (ADS)

Jang, Il-Yong; Huh, Sung-Min; Moon, Seong-Yong; Woo, Sang-Gyun; Lee, Jin-Kwan; Moon, Sang Heup; Cho, HanKu

2008-10-01

A patterned TaN substrate, which is candidate for a mask absorber in extreme ultra-violet lithography (EUVL), was etched to have inclined sidewalls by using a Faraday cage system under the condition of a 2-step process that allowed the high etch selectivity of TaN over the resist. The sidewall angle (SWA) of the patterned substrate, which was in the shape of a parallelogram after etching, could be controlled by changing the slope of a substrate holder that was placed in the Faraday cage. The performance of an EUV mask, which contained the TaN absorber of an oblique pattern over the molybdenum/silicon multi-layer, was simulated for different cases of SWA. The results indicated that the optical properties, such as the critical dimension (CD), an offset in the CD bias between horizontal and vertical patterns (H-V bias), and a shift in the image position on the wafer, could be controlled by changing the SWA of the absorber stack. The simulation result showed that the effect of the SWA on the optical properties became more significant at larger thicknesses of the absorber and smaller sizes of the target CD. Nevertheless, the contrast of the aerial images was not significantly decreased because the shadow effect caused by either sidewall of the patterned substrate cancelled with each other.

Incorporating DSA in multipatterning semiconductor manufacturing technologies

NASA Astrophysics Data System (ADS)

Badr, Yasmine; Torres, J. A.; Ma, Yuansheng; Mitra, Joydeep; Gupta, Puneet

2015-03-01

Multi-patterning (MP) is the process of record for many sub-10nm process technologies. The drive to higher densities has required the use of double and triple patterning for several layers; but this increases the cost of the new processes especially for low volume products in which the mask set is a large percentage of the total cost. For that reason there has been a strong incentive to develop technologies like Directed Self Assembly (DSA), EUV or E-beam direct write to reduce the total number of masks needed in a new technology node. Because of the nature of the technology, DSA cylinder graphoepitaxy only allows single-size holes in a single patterning approach. However, by integrating DSA and MP into a hybrid DSA-MP process, it is possible to come up with decomposition approaches that increase the design flexibility, allowing different size holes or bar structures by independently changing the process for every patterning step. A simple approach to integrate multi-patterning with DSA is to perform DSA grouping and MP decomposition in sequence whether it is: grouping-then-decomposition or decomposition-then-grouping; and each of the two sequences has its pros and cons. However, this paper describes why these intuitive approaches do not produce results of acceptable quality from the point of view of design compliance and we highlight the need for custom DSA-aware MP algorithms.

EUV lithography for 22nm half pitch and beyond: exploring resolution, LWR, and sensitivity tradeoffs

NASA Astrophysics Data System (ADS)

Putna, E. Steve; Younkin, Todd R.; Leeson, Michael; Caudillo, Roman; Bacuita, Terence; Shah, Uday; Chandhok, Manish

2011-04-01

The International Technology Roadmap for Semiconductors (ITRS) denotes Extreme Ultraviolet (EUV) lithography as a leading technology option for realizing the 22nm half pitch node and beyond. According to recent assessments made at the 2010 EUVL Symposium, the readiness of EUV materials remains one of the top risk items for EUV adoption. The main development issue regarding EUV resists has been how to simultaneously achieve high resolution, high sensitivity, and low line width roughness (LWR). This paper describes our strategy, the current status of EUV materials, and the integrated post-development LWR reduction efforts made at Intel Corporation. Data collected utilizing Intel's Micro- Exposure Tool (MET) is presented in order to examine the feasibility of establishing a resist process that simultaneously exhibits <=22nm half-pitch (HP) L/S resolution at <=11.3mJ/cm2 with <=3nm LWR.

Degradation-Free Spectrometers for Solar EUV Measurements: A Progress Report

NASA Astrophysics Data System (ADS)

Wieman, S. R.; Judge, D. L.; Didkovsky, L. V.

2009-12-01

Solar EUV observations will be made using two new degradation-free EUV spectrometers on a sounding rocket flight scheduled for Summer 2010. The two instruments, a rare gas photoionization-based Optics-Free Spectrometer (OFS) and a Dual Grating Spectrometer (DGS), are filter-free and optics-free. OFS can measure the solar EUV spectrum with a spectral resolution comparable to that of grating-based EUV spectrometers. The DGS is designed to provide solar irradiance at Lyman-alpha and He II to overlap EUV observations from SOHO/SEM and SDO/EVE. Electronic and mechanical designs for the flight prototype instruments and results of tests performed with the instruments in the laboratory are reported. The spectrometers are being developed and demonstrated as part of the Degradation Free Spectrometers (DFS) project under NASA’s Low Cost Access to Space (LCAS) program and are supported by NASA Grant NNX08BA12G.

Single-expose patterning development for EUV lithography

NASA Astrophysics Data System (ADS)

De Silva, Anuja; Petrillo, Karen; Meli, Luciana; Shearer, Jeffrey C.; Beique, Genevieve; Sun, Lei; Seshadri, Indira; Oh, Taehwan; Han, Seulgi; Saulnier, Nicole; Lee, Joe; Arnold, John C.; Hamieh, Bassem; Felix, Nelson M.; Furukawa, Tsuyoshi; Singh, Lovejeet; Ayothi, Ramakrishnan

2017-03-01

Initial readiness of EUV (extreme ultraviolet) patterning was demonstrated in 2016 with IBM Alliance's 7nm device technology. The focus has now shifted to driving the 'effective' k1 factor and enabling the second generation of EUV patterning. With the substantial cost of EUV exposure there is significant interest in extending the capability to do single exposure patterning with EUV. To enable this, emphasis must be placed on the aspect ratios, adhesion, defectivity reduction, etch selectivity, and imaging control of the whole patterning process. Innovations in resist materials and processes must be included to realize the full entitlement of EUV lithography at 0.33NA. In addition, enhancements in the patterning process to enable good defectivity, lithographic process window, and post etch pattern fidelity are also required. Through this work, the fundamental material challenges in driving down the effective k1 factor will be highlighted.

Plans for the extreme ultraviolet explorer data base

NASA Technical Reports Server (NTRS)

Marshall, Herman L.; Dobson, Carl A.; Malina, Roger F.; Bowyer, Stuart

1988-01-01

The paper presents an approach for storage and fast access to data that will be obtained by the Extreme Ultraviolet Explorer (EUVE), a satellite payload scheduled for launch in 1991. The EUVE telescopes will be operated remotely from the EUVE Science Operation Center (SOC) located at the University of California, Berkeley. The EUVE science payload consists of three scanning telescope carrying out an all-sky survey in the 80-800 A spectral region and a Deep Survey/Spectrometer telescope performing a deep survey in the 80-250 A spectral region. Guest Observers will remotely access the EUVE spectrometer database at the SOC. The EUVE database will consist of about 2 X 10 to the 10th bytes of information in a very compact form, very similar to the raw telemetry data. A history file will be built concurrently giving telescope parameters, command history, attitude summaries, engineering summaries, anomalous events, and ephemeris summaries.

An Extreme-ultraviolet Wave Generating Upward Secondary Waves in a Streamer-like Solar Structure

NASA Astrophysics Data System (ADS)

Zheng, Ruisheng; Chen, Yao; Feng, Shiwei; Wang, Bing; Song, Hongqiang

2018-05-01

Extreme-ultraviolet (EUV) waves, spectacular horizontally propagating disturbances in the low solar corona, always trigger horizontal secondary waves (SWs) when they encounter the ambient coronal structure. We present the first example of upward SWs in a streamer-like structure after the passing of an EUV wave. This event occurred on 2017 June 1. The EUV wave happened during a typical solar eruption including a filament eruption, a coronal mass ejection (CME), and a C6.6 flare. The EUV wave was associated with quasi-periodic fast propagating (QFP) wave trains and a type II radio burst that represented the existence of a coronal shock. The EUV wave had a fast initial velocity of ∼1000 km s‑1, comparable to high speeds of the shock and the QFP wave trains. Intriguingly, upward SWs rose slowly (∼80 km s‑1) in the streamer-like structure after the sweeping of the EUV wave. The upward SWs seemed to originate from limb brightenings that were caused by the EUV wave. All of the results show that the EUV wave is a fast-mode magnetohydrodynamic (MHD) shock wave, likely triggered by the flare impulses. We suggest that part of the EUV wave was probably trapped in the closed magnetic fields of the streamer-like structure, and upward SWs possibly resulted from the release of slow-mode trapped waves. It is believed that the interplay of the strong compression of the coronal shock and the configuration of the streamer-like structure is crucial for the formation of upward SWs.

Extreme ultraviolet spectral irradiance measurements since 1946

NASA Astrophysics Data System (ADS)

Schmidtke, G.

2015-03-01

In the physics of the upper atmosphere the solar extreme ultraviolet (EUV) radiation plays a dominant role controlling most of the thermospheric/ionospheric (T/I) processes. Since this part of the solar spectrum is absorbed in the thermosphere, platforms to measure the EUV fluxes became only available with the development of rockets reaching altitude levels exceeding 80 km. With the availability of V2 rockets used in space research, recording of EUV spectra started in 1946 using photographic films. The development of pointing devices to accurately orient the spectrographs toward the sun initiated intense activities in solar-terrestrial research. The application of photoelectric recording technology enabled the scientists placing EUV spectrometers aboard satellites observing qualitatively strong variability of the solar EUV irradiance on short-, medium-, and long-term scales. However, as more measurements were performed more radiometric EUV data diverged due to the inherent degradation of the EUV instruments with time. Also, continuous recording of the EUV energy input to the T/I system was not achieved. It is only at the end of the last century that there was progress made in solving the serious problem of degradation enabling to monitore solar EUV fluxes with sufficient radiometric accuracy. The data sets available allow composing the data available to the first set of EUV data covering a period of 11 years for the first time. Based on the sophisticated instrumentation verified in space, future EUV measurements of the solar spectral irradiance (SSI) are promising accuracy levels of about 5% and less. With added low-cost equipment, real-time measurements will allow providing data needed in ionospheric modeling, e.g., for correcting propagation delays of navigation signals from space to earth. Adding EUV airglow and auroral emission monitoring by airglow cameras, the impact of space weather on the terrestrial T/I system can be studied with a spectral terrestrial irradiance camera (STI-Cam) and also be used investigating real-time space weather effects and deriving more detailed correction procedures for the evaluation of Global Navigation Satellite System (GNSS) signals. Progress in physics goes with achieving higher accuracy in measurements. This review historically guides the reader on the ways of exploring the impact of the variable solar radiation in the extreme ultraviolet spectral region on our upper atmosphere in the altitude regime from 80 to 1000 km.

Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years

NASA Astrophysics Data System (ADS)

Čížková, Klára; Láska, Kamil; Metelka, Ladislav; Staněk, Martin

2018-02-01

This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964-2013. The EUV radiation time series was reconstructed using a radiative transfer model and additional empirical relationships, with the final root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which was linked to the steep decline in total ozone (10 % per decade). The changes in cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004-2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover, and surface UV albedo for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and the meridional inflow of ozone-poor air from the southwest were favorable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macroscale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.

Light sources for high-volume manufacturing EUV lithography: technology, performance, and power scaling

NASA Astrophysics Data System (ADS)

Fomenkov, Igor; Brandt, David; Ershov, Alex; Schafgans, Alexander; Tao, Yezheng; Vaschenko, Georgiy; Rokitski, Slava; Kats, Michael; Vargas, Michael; Purvis, Michael; Rafac, Rob; La Fontaine, Bruno; De Dea, Silvia; LaForge, Andrew; Stewart, Jayson; Chang, Steven; Graham, Matthew; Riggs, Daniel; Taylor, Ted; Abraham, Mathew; Brown, Daniel

2017-06-01

Extreme ultraviolet (EUV) lithography is expected to succeed in 193-nm immersion multi-patterning technology for sub-10-nm critical layer patterning. In order to be successful, EUV lithography has to demonstrate that it can satisfy the industry requirements in the following critical areas: power, dose stability, etendue, spectral content, and lifetime. Currently, development of second-generation laser-produced plasma (LPP) light sources for the ASML's NXE:3300B EUV scanner is complete, and first units are installed and operational at chipmaker customers. We describe different aspects and performance characteristics of the sources, dose stability results, power scaling, and availability data for EUV sources and also report new development results.

Coordinated XTE/EUVE Observations of Algol

NASA Technical Reports Server (NTRS)

Stern, Robert A.

1997-01-01

EUVE, ASCA, and XTE observed the eclipsing binary Algol (Beta Per) from 1-7 Feb. 96. The coordinated observation covered approximately 2 binary orbits of the system, with a net exposure of approximately 160 ksec for EUVE, 40 ksec for ASCA (in 4 pointing), and 90 ksec for XTE (in 45 pointings). We discuss results of modeling the combined EUVE, ASCA, and XTE data using continuous differential emission measure distributions, and provide constraints on the Fe abundance in the Algol system.

Seasonal variability of Martian ion escape through the plume and tail from MAVEN observations

NASA Astrophysics Data System (ADS)

Dong, Y.; Fang, X.; Brain, D. A.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.; Eparvier, F.; Andersson, L.; Mitchell, D.; Jakosky, B. M.

2017-04-01

We study the Mars Atmosphere and Volatile Evolution spacecraft observations of Martian planetary ion escape during two time periods: 11 November 2014 to 19 March 2015 and 4 June 2015 to 24 October 2015, with the focus on understanding the seasonal variability of Martian ion escape in response to the solar extreme ultraviolet (EUV) flux. We organize the >6 eV O+ ion data by the upstream electric field direction to estimate the escape rates through the plume and tail. To investigate the ion escape dependence on the solar EUV flux, we constrain the solar wind dynamic pressure and interplanetary magnetic filed strength and compare the ion escape rates through the plume and tail in different energy ranges under high and low EUV conditions. We found that the total >6 eV O+ escape rate increases from 2 to 3 × 1024 s-1 as the EUV irradiance increases by almost the same factor, mostly on the <1 keV tailward escape. The plume escape rate does not vary significantly with EUV. The relative contribution from the plume to the total escape varies between 30% and 20% from low to high EUV. Our results suggest that the Martian ion escape is sensitive to the seasonal EUV variation, and the contribution from plume escape becomes more important under low EUV conditions.

Update on EUV radiometry at PTB

NASA Astrophysics Data System (ADS)

Laubis, Christian; Barboutis, Annett; Buchholz, Christian; Fischer, Andreas; Haase, Anton; Knorr, Florian; Mentzel, Heiko; Puls, Jana; Schönstedt, Anja; Sintschuk, Michael; Soltwisch, Victor; Stadelhoff, Christian; Scholze, Frank

2016-03-01

The development of technology infrastructure for EUV Lithography (EUVL) still requires higher levels of technology readiness in many fields. A large number of new materials will need to be introduced. For example, development of EUV compatible pellicles to adopt an approved method from optical lithography for EUVL needs completely new thin membranes which have not been available before. To support these developments, PTB with its decades of experience [1] in EUV metrology [2] provides a wide range of actinic and non actinic measurements at in-band EUV wavelengths as well as out of band. Two dedicated, complimentary EUV beamlines [3] are available for radiometric [4,5] characterizations benefiting from small divergence or from adjustable spot size respectively. The wavelength range covered reaches from below 1 nm to 45 nm [6] for the EUV beamlines [7] to longer wavelengths if in addition the VUV beamline is employed. The standard spot size is 1 mm by 1 mm with an option to go as low as 0.1 mm to 0.1 mm. A separate beamline offers an exposure setup. Exposure power levels of 20 W/cm2 have been employed in the past, lower fluencies are available by attenuation or out of focus exposure. Owing to a differential pumping stage, the sample can be held under defined gas conditions during exposure. We present an updated overview on our instrumentation and analysis capabilities for EUV metrology and provide data for illustration.

EUV Spectroscopy of High-redshift X-ray Objects

NASA Astrophysics Data System (ADS)

Kowalski, Michael Paul; Wolff, M. T.; Wood, K. S.; Barbee, T. W., Jr.

2010-03-01

As astronomical observations are pushed to cosmological distances (z>3) the spectral energy distributions of X-ray objects, AGNs for example, will have their maxima redshifted into the EUV waveband ( 90-912 Å/0.1-0.01 keV). Consequently, a wealth of spectral diagnostics, provided by, for example, the Fe L-shell complex ( 60-6 Å/0.2-2.0 keV) and the O VII/VIII lines ( 20 Å/0.5 keV), will be lost to X-ray instruments operating at traditional ( 0.5-10 keV) and higher X-ray energies. There are precedents in other wavebands. For example, HST evolutionary studies will become largely the province of JWST. Despite the successes of EUVE, the ROSAT WFC, and the Chandra LETG, the EUV continues to be unappreciated and under-utilized, partly because of a preconception that absorption by neutral galactic Hydrogen in the ISM prevents any useful extragalactic measurements at all EUV wavelengths and, until recently, by a lack of a suitable enabling technology. Thus, if future planned X-ray missions (e.g., IXO, Gen-X) are optimized again for traditional X-ray energies, their performance (effective area, resolving power) will be cut off at ultrasoft X-ray energies or at best be radically reduced in the EUV. This opens up a critical gap in performance located right at short EUV wavelengths, where the critical X-ray spectral transitions occur in high-z objects. However, normal-incidence multilayer-grating technology, which performs best precisely at such wavelengths, together with advanced nano-laminate fabrication techniques have been developed and are now mature to the point where advanced EUV instrument designs with performance complementary to IXO and Gen-X are practical. Such EUV instruments could be flown either independently or as secondary instruments on these X-ray missions. We present here a critical examination of the limits placed on extragalactic EUV measurements by ISM absorption, the range where high-z measurements are practical, and the requirements this imposes on next-generation instrument designs.

Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Overview of Science Objectives, Instrument Design, Data Products, and Model Developments

NASA Technical Reports Server (NTRS)

Woods, T. N.; Eparvier, F. G.; Hock, R.; Jones, A. R.; Woodraska, D.; Judge, D.; Didkovsky, L.; Lean, J.; Mariska, J.; Warren, H.;

EUV Waves Driven by the Sudden Expansion of Transequatorial Loops Caused by Coronal Jets

NASA Astrophysics Data System (ADS)

Shen, Yuandeng; Tang, Zehao; Miao, Yuhu; Su, Jiangtao; Liu, Yu

2018-06-01

We present two events to study the driving mechanism of extreme-ultraviolet (EUV) waves that are not associated with coronal mass ejections (CMEs), by using high-resolution observations taken by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Observational results indicate that the observed EUV waves were accompanied by flares and coronal jets, but not the CMEs that were regarded as drivers of most EUV waves in previous studies. In the first case, it is observed that a coronal jet is ejected along a transequatorial loop system at a plane-of-the-sky (POS) speed of 335 ± 22 km s{}-1; in the meantime, an arc-shaped EUV wave appeared on the eastern side of the loop system. In addition, the EUV wave further interacted with another interconnecting loop system and launched a fast propagating (QFP) magnetosonic wave along the loop system, which had a period of 200 s and a speed of 388 ± 65 km s{}-1, respectively. In the second case, we observed a coronal jet that ejected at a POS speed of 282 ± 44 km s{}-1 along a transequatorial loop system as well as the generation of bright EUV waves on the eastern side of the loop system. Based on the observational results, we propose that the observed EUV waves on the eastern side of the transequatorial loop systems are fast-mode magnetosonic waves and that they are driven by the sudden lateral expansion of the transequatorial loop systems due to the direct impingement of the associated coronal jets, while the QFP wave in the fist case formed due to the dispersive evolution of the disturbance caused by the interaction between the EUV wave and the interconnecting coronal loops. It is noted that EUV waves driven by sudden loop expansions have shorter lifetimes than those driven by CMEs.

Maskless EUV lithography: an already difficult technology made even more complicated?

NASA Astrophysics Data System (ADS)

Chen, Yijian

2012-03-01

In this paper, we present the research progress made in maskless EUV lithography and discuss the emerging opportunities for this disruptive technology. It will be shown nanomirrors based maskless approach is one path to costeffective and defect-free EUV lithography, rather than making it even more complicated. The focus of our work is to optimize the existing vertical comb process and scale down the mirror size from several microns to sub-micron regime. The nanomirror device scaling, system configuration, and design issues will be addressed. We also report our theoretical and simulation study of reflective EUV nanomirror based imaging behavior. Dense line/space patterns are formed with an EUV nanomirror array by assigning a phase shift of π to neighboring nanomirrors. Our simulation results show that phase/intensity imbalance is an inherent characteristic of maskless EUV lithography while it only poses a manageable challenge to CD control and process window. The wafer scan and EUV laser jitter induced image blur phenomenon is discussed and a blurred imaging theory is constructed. This blur effect is found to degrade the image contrast at a level that mainly depends on the wafer scan speed.

Progress in mask replication using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Selinidis, Kosta S.; Brooks, Cynthia B.; Doyle, Gary F.; Brown, Laura; Jones, Chris; Imhof, Joseph; LaBrake, Dwayne L.; Resnick, Douglas J.; Sreenivasan, S. V.

2011-04-01

The Jet and Flash Imprint Lithography (J-FILTM) process uses drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for memory markets including Flash memory and patterned media for hard disk drives. It is anticipated that the lifetime of a single template (for patterned media) or mask (for semiconductor) will be on the order of 104 - 105imprints. This suggests that tens of thousands of templates/masks will be required to satisfy the needs of a manufacturing environment. Electron-beam patterning is too slow to feasibly deliver these volumes, but instead can provide a high quality "master" mask which can be replicated many times with an imprint lithography tool. This strategy has the capability to produce the required supply of "working" templates/masks. In this paper, we review the development of the mask form factor, imprint replication tools and processes specifically for semiconductor applications. The requirements needed for semiconductors dictate the need for a well defined form factor for both master and replica masks which is also compatible with the existing mask infrastructure established for the 6025 semi standard, 6" x 6" x 0.25" photomasks. Complying with this standard provides the necessary tooling needed for mask fabrication processes, cleaning, metrology, and inspection. The replica form factor has additional features specific to imprinting such as a pre-patterned mesa. A PerfectaTM MR5000 mask replication tool has been developed specifically to pattern replica masks from an e-beam written master. The system specifications include a throughput of four replicas per hour with an added image placement component of 5nm, 3sigma and a critical dimension uniformity error of less than 1nm, 3sigma. A new process has been developed to fabricate replicas with high contrast alignment marks so that designs for imprint can fit within current device layouts and maximize the usable printed area on the wafer. Initial performance results of this marks are comparable to the baseline fused silica align marks.

High reflectance coatings for space applications in the EUV

NASA Technical Reports Server (NTRS)

Keski-Kuha, Ritva A. M.; Gum, Jeffrey S.; Osantowski, John F.; Fleetwood, Charles M.

1993-01-01

Advances in optical coating and materials technology have made possible the development of instruments with substantially improved efficiency and made possible to consider more complex optical designs in the EUV. The importance of recent developments in chemical vapor deposited silicon carbide (CVD-SiC), SiC films and multilayer coatings is discussed in the context of EUV instrumentation design. The EUV performance of these coatings as well as some strengths and problem areas for their use in space will be addressed.

Modeling 13.3nm Fe XXIII Flare Emissions Using the GOES-R EXIS Instrument

NASA Astrophysics Data System (ADS)

Rook, H.; Thiemann, E.

2017-12-01

The solar EUV spectrum is dominated by atomic transitions in ionized atoms in the solar atmosphere. As solar flares evolve, plasma temperatures and densities change, influencing abundances of various ions, changing intensities of different EUV wavelengths observed from the sun. Quantifying solar flare spectral irradiance is important for constraining models of Earth's atmosphere, improving communications quality, and controlling satellite navigation. However, high time cadence measurements of flare irradiance across the entire EUV spectrum were not available prior to the launch of SDO. The EVE MEGS-A instrument aboard SDO collected 0.1nm EUV spectrum data from 2010 until 2014, when the instrument failed. No current or future instrument is capable of similar high resolution and time cadence EUV observation. This necessitates a full EUV spectrum model to study EUV phenomena at Earth. It has been recently demonstrated that one hot flare EUV line, such as the 13.3nm Fe XXIII line, can be used to model cooler flare EUV line emissions, filling the role of MEGS-A. Since unblended measurements of Fe XXIII are typically unavailable, a proxy for the Fe XXIII line must be found. In this study, we construct two models of this line, first using the GOES 0.1-0.8nm soft x-ray (SXR) channel as the Fe XXIII proxy, and second using a physics-based model dependent on GOES emission measure and temperature data. We determine that the more sophisticated physics-based model shows better agreement with Fe XXIII measurements, although the simple proxy model also performs well. We also conclude that the high correlation between Fe XXIII emissions and the GOES 0.1-0.8nm band is because both emissions tend to peak near the GOES emission measure peak despite large differences in their contribution functions.

Photomask quality assessment solution for 90-nm technology node

NASA Astrophysics Data System (ADS)

Ohira, Katsumi; Chung, Dong Hoon P.; Nobuyuki, Yoshioka; Tateno, Motonari; Matsumura, Kenichi; Chen, Jiunn-Hung; Luk-Pat, Gerard T.; Fukui, Norio; Tanaka, Yoshio

2004-08-01

As 90 nm LSI devices are about to enter pre-production, the cost and turn-around time of photomasks for such devices will be key factors for success in device production. Such devices will be manufactured with state-of-the-art 193nm photolithography systems. Photomasks for these devices are being produced with the most advanced equipment, material and processing technologies and yet, quality assurance still remains an issue for volume production. These issues include defect classification and disposition due to the insufficient resolution of the defect inspection system at conventional review and classification processes and to aggressive RETs, uncertainty of the impact the defects have on the printed feature as well as inconsistencies of classical defect specifications as applied in the sub-wavelength era are becoming a serious problem. Simulation-based photomask qualification using the Virtual Stepper System is widely accepted today as a reliable mask quality assessment tool of mask defects for both the 180 nm and 130 nm technology nodes. This study examines the extendibility of the Virtual Stepper System to 90nm technology node. The proposed method of simulation-based mask qualification uses aerial image defect simulation in combination with a next generation DUV inspection system with shorter wavelength (266nm) and small pixel size combined with DUV high-resolution microscope for some defect cases. This paper will present experimental results that prove the applicability for enabling 90nm technology nodes. Both contact and line/space patterns with varies programmed defects on ArF Attenuated PSM will be used. This paper will also address how to make the strategy production-worthy.

The Extreme Ultraviolet Flux of Very Low Mass Stars

NASA Astrophysics Data System (ADS)

Drake, Jeremy

2017-09-01

The X-ray and EUV emission of stars is vital for understanding the atmospheres and evolution of their planets. The coronae of dwarf stars later than M6 behave differently to those of earlier spectral types and are more X-ray dim and radio bright. Too faint to have been observed by EUVE, their EUV behavior is currently highly uncertain. We propose to observe a small sample of late M dwarfs using the off-axis HRC-S thin Al" filter that is sensitive to EUV emission in the 50-200 A range. The measured fluxes will be used to understand the amount of cooler coronal plasma present, and extend X-ray-EUV flux relations to the latest stellar types.

The capability of lithography simulation based on MVM-SEM® system

NASA Astrophysics Data System (ADS)

Yoshikawa, Shingo; Fujii, Nobuaki; Kanno, Koichi; Imai, Hidemichi; Hayano, Katsuya; Miyashita, Hiroyuki; Shida, Soichi; Murakawa, Tsutomu; Kuribara, Masayuki; Matsumoto, Jun; Nakamura, Takayuki; Matsushita, Shohei; Hara, Daisuke; Pang, Linyong

2015-10-01

The 1Xnm technology node lithography is using SMO-ILT, NTD or more complex pattern. Therefore in mask defect inspection, defect verification becomes more difficult because many nuisance defects are detected in aggressive mask feature. One key Technology of mask manufacture is defect verification to use aerial image simulator or other printability simulation. AIMS™ Technology is excellent correlation for the wafer and standards tool for defect verification however it is difficult for verification over hundred numbers or more. We reported capability of defect verification based on lithography simulation with a SEM system that architecture and software is excellent correlation for simple line and space.[1] In this paper, we use a SEM system for the next generation combined with a lithography simulation tool for SMO-ILT, NTD and other complex pattern lithography. Furthermore we will use three dimension (3D) lithography simulation based on Multi Vision Metrology SEM system. Finally, we will confirm the performance of the 2D and 3D lithography simulation based on SEM system for a photomask verification.

Study on photochemical analysis system (VLES) for EUV lithography

NASA Astrophysics Data System (ADS)

Sekiguchi, A.; Kono, Y.; Kadoi, M.; Minami, Y.; Kozawa, T.; Tagawa, S.; Gustafson, D.; Blackborow, P.

2007-03-01

A system for photo-chemical analysis of EUV lithography processes has been developed. This system has consists of 3 units: (1) an exposure that uses the Z-Pinch (Energetiq Tech.) EUV Light source (DPP) to carry out a flood exposure, (2) a measurement system RDA (Litho Tech Japan) for the development rate of photo-resists, and (3) a simulation unit that utilizes PROLITH (KLA-Tencor) to calculate the resist profiles and process latitude using the measured development rate data. With this system, preliminary evaluation of the performance of EUV lithography can be performed without any lithography tool (Stepper and Scanner system) that is capable of imaging and alignment. Profiles for 32 nm line and space pattern are simulated for the EUV resist (Posi-2 resist by TOK) by using VLES that hat has sensitivity at the 13.5nm wavelength. The simulation successfully predicts the resist behavior. Thus it is confirmed that the system enables efficient evaluation of the performance of EUV lithography processes.

Estimation of resist sensitivity for extreme ultraviolet lithography using an electron beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oyama, Tomoko Gowa, E-mail: ohyama.tomoko@qst.go.jp; Oshima, Akihiro; Tagawa, Seiichi, E-mail: tagawa@sanken.osaka-u.ac.jp

2016-08-15

It is a challenge to obtain sufficient extreme ultraviolet (EUV) exposure time for fundamental research on developing a new class of high sensitivity resists for extreme ultraviolet lithography (EUVL) because there are few EUV exposure tools that are very expensive. In this paper, we introduce an easy method for predicting EUV resist sensitivity by using conventional electron beam (EB) sources. If the chemical reactions induced by two ionizing sources (EB and EUV) are the same, the required absorbed energies corresponding to each required exposure dose (sensitivity) for the EB and EUV would be almost equivalent. Based on this theory, wemore » calculated the resist sensitivities for the EUV/soft X-ray region. The estimated sensitivities were found to be comparable to the experimentally obtained sensitivities. It was concluded that EB is a very useful exposure tool that accelerates the development of new resists and sensitivity enhancement processes for 13.5 nm EUVL and 6.x nm beyond-EUVL (BEUVL).« less

AWARE - The Automated EUV Wave Analysis and REduction algorithm

NASA Astrophysics Data System (ADS)

Ireland, J.; Inglis; A. R.; Shih, A. Y.; Christe, S.; Mumford, S.; Hayes, L. A.; Thompson, B. J.

2016-10-01

Extreme ultraviolet (EUV) waves are large-scale propagating disturbances observed in the solar corona, frequently associated with coronal mass ejections and flares. Since their discovery over two hundred papers discussing their properties, causes and physics have been published. However, their fundamental nature and the physics of their interactions with other solar phenomena are still not understood. To further the understanding of EUV waves, and their relation to other solar phenomena, we have constructed the Automated Wave Analysis and REduction (AWARE) algorithm for the detection of EUV waves over the full Sun. The AWARE algorithm is based on a novel image processing approach to isolating the bright wavefront of the EUV as it propagates across the corona. AWARE detects the presence of a wavefront, and measures the distance, velocity and acceleration of that wavefront across the Sun. Results from AWARE are compared to results from other algorithms for some well known EUV wave events. Suggestions are also give for further refinements to the basic algorithm presented here.

Ionospheric Change and Solar EUV Irradiance

NASA Astrophysics Data System (ADS)

Sojka, J. J.; David, M.; Jensen, J. B.; Schunk, R. W.

2011-12-01

The ionosphere has been quantitatively monitored for the past six solar cycles. The past few years of observations are showing trends that differ from the prior cycles! Our good statistical relationships between the solar radio flux index at 10.7 cm, the solar EUV Irradiance, and the ionospheric F-layer peak density are showing indications of divergence! Present day discussion of the Sun-Earth entering a Dalton Minimum would suggest change is occurring in the Sun, as the driver, followed by the Earth, as the receptor. The dayside ionosphere is driven by the solar EUV Irradiance. But different components of this spectrum affect the ionospheric layers differently. For a first time the continuous high cadence EUV spectra from the SDO EVE instrument enable ionospheric scientists the opportunity to evaluate solar EUV variability as a driver of ionospheric variability. A definitive understanding of which spectral components are responsible for the E- and F-layers of the ionosphere will enable assessments of how over 50 years of ionospheric observations, the solar EUV Irradiance has changed. If indeed the evidence suggesting the Sun-Earth system is entering a Dalton Minimum periods is correct, then the comprehensive EVE solar EUV Irradiance data base combined with the ongoing ionospheric data bases will provide a most fortuitous fiduciary reference baseline for Sun-Earth dependencies. Using the EVE EUV Irradiances, a physics based ionospheric model (TDIM), and 50 plus years of ionospheric observation from Wallops Island (Virginia) the above Sun-Earth ionospheric relationship will be reported on.

Current status of x-ray mask manufacturing at the Microlithographic Mask Development Center

NASA Astrophysics Data System (ADS)

Kimmel, Kurt R.; Hughes, Patrick J.

1996-07-01

The Microlithographic Mask Development Center (MMD) has been the focal point of X-ray mask development efforts in the United States since its inception in 1993. Funded by the Advanced Research Projects Agency (ARPA), and with technical support from the Proximity X-ray Lithography Association (AT&T, IBM, Loral Federal Systems, and Motorola) the MMD has recently made dramatic advances in mask fabrication. Numerous defect-free 64Mb and 256Mb DRAM masks have been made on both boron-doped silicon and silicon carbide substrates. Image-placement error of less than 35nm 3 sigma is achieved with high yield. Image-size (critical dimension) control of 25nm 3 sigma on 250nm nominal images is representative performance. This progress is being made in a manufacturing environment with significant volumes, multiple customers, multiple substrate configurations, and fast turnaround-time (TAT) requirements. The MMD state-of-the-art equipment infrastructure has made much of this progress possible. This year the MMD qualified the EL-4, an IBM-designed-and-built variable-shaped-spot e-beam system. The fundamental performance parameters of this system will be described. Operational techniques of multiple partial exposure writing and product specific emulation (PSE) have been implemented to improve image-placement accuracy with remarkable success. Image-size control was studied in detail with contributory components separated. Defect density was systematically reduced to yield defect-free masks while simultaneously tightening inspection criteria. Information about these and other recent engineering highlights will be reported. An outline of the primary engineering challenges and goals for 1996 and status of progress toward 100 nm design rule capability will also be given.

EUVE observations of the Moon

NASA Technical Reports Server (NTRS)

Gladstone, G. R.; Mcdonald, J. S.; Boyd, W. T.

1993-01-01

During its all-sky survey, the Extreme Ultraviolet Explorer (EUVE) satellite observed the Moon several times at first and last quarters, and once near the Dec. 10, 1992 lunar eclipse. We present a preliminary reduction and analysis of this data, in the form of EUV images of the Moon and derived albedos.

Coordinated ASCA/EUVE/XTE Observations of Algol

NASA Technical Reports Server (NTRS)

Stern, Robert A.

1997-01-01

EUVE, Advanced Satellite for Cosmology and Astrophysics (ASCA), and X-ray Timing Explorer (XTE) observed the eclipsing binary Algol (Beta Per) from 1-7 Feb 1996. The coordinated observation covered approx. 2 binary orbits of the system, with a net exposure of approx. 160 ksec for EUVE, 40 ksec for ASCA (in 4 pointings), and 90 ksec for XTE (in 45 pointings). We discuss results of modeling the combined EUVE, ASCA, and XTE data using continuous differential emission measure distributions, and provide constraints on the abundance in the Algol system.

The Extreme Ultraviolet Explorer

NASA Technical Reports Server (NTRS)

Malina, R. F.; Bowyer, S.; Lampton, M.; Finley, D.; Paresce, F.; Penegor, G.; Heetderks, H.

1982-01-01

The Extreme Ultraviolet Explorer Mission is described. The purpose of this mission is to search the celestial sphere for astronomical sources of extreme ultraviolet (EUV) radiation (100 to 1000 A). The search will be accomplished with the use of three EUV telescopes, each sensitive to different bands within the EUV band. A fourth telescope will perform a higher sensitivity search of a limited sample of the sky in a single EUV band. In six months, the entire sky will be scanned at a sensitivity level comparable to existing surveys in other more traditional astronomical bandpasses.

EUV lithography for 30nm half pitch and beyond: exploring resolution, sensitivity, and LWR tradeoffs

NASA Astrophysics Data System (ADS)

Putna, E. Steve; Younkin, Todd R.; Chandhok, Manish; Frasure, Kent

2009-03-01

The International Technology Roadmap for Semiconductors (ITRS) denotes Extreme Ultraviolet (EUV) lithography as a leading technology option for realizing the 32nm half-pitch node and beyond. Readiness of EUV materials is currently one high risk area according to assessments made at the 2008 EUVL Symposium. The main development issue regarding EUV resist has been how to simultaneously achieve high sensitivity, high resolution, and low line width roughness (LWR). This paper describes the strategy and current status of EUV resist development at Intel Corporation. Data is presented utilizing Intel's Micro-Exposure Tool (MET) examining the feasibility of establishing a resist process that simultaneously exhibits <=30nm half-pitch (HP) L/S resolution at <=10mJ/cm2 with <=4nm LWR.

EUV lithography for 22nm half pitch and beyond: exploring resolution, LWR, and sensitivity tradeoffs

NASA Astrophysics Data System (ADS)

Putna, E. Steve; Younkin, Todd R.; Caudillo, Roman; Chandhok, Manish

2010-04-01

The International Technology Roadmap for Semiconductors (ITRS) denotes Extreme Ultraviolet (EUV) lithography as a leading technology option for realizing the 22nm half pitch node and beyond. Readiness of EUV materials is currently one high risk area according to recent assessments made at the 2009 EUVL Symposium. The main development issue regarding EUV resist has been how to simultaneously achieve high sensitivity, high resolution, and low line width roughness (LWR). This paper describes the strategy and current status of EUV resist development at Intel Corporation. Data collected utilizing Intel's Micro-Exposure Tool (MET) is presented in order to examine the feasibility of establishing a resist process that simultaneously exhibits <=22nm half-pitch (HP) L/S resolution at <= 12.5mJ/cm2 with <= 4nm LWR.

Utilizing the EUVE Innovative Technology Testbed to Reduce Operations Cost for Present and Future Orbiting Mission

NASA Technical Reports Server (NTRS)

1997-01-01

This report summarizes work done under Cooperative Agreement (CA) on the following testbed projects: TERRIERS - The development of the ground systems to support the TERRIERS satellite mission at Boston University (BU). HSTS - The application of ARC's Heuristic Scheduling Testbed System (HSTS) to the EUVE satellite mission. SELMON - The application of NASA's Jet Propulsion Laboratory's (JPL) Selective Monitoring (SELMON) system to the EUVE satellite mission. EVE - The development of the EUVE Virtual Environment (EVE), a prototype three-dimensional (3-D) visualization environment for the EUVE satellite and its sensors, instruments, and communications antennae. FIDO - The development of the Fault-Induced Document Officer (FIDO) system, a prototype application to respond to anomalous conditions by automatically searching for, retrieving, and displaying relevant documentation for an operators use.

Continued Analysis of EUVE Solar System Observations

NASA Technical Reports Server (NTRS)

Gladstone, G. Randall

2001-01-01

This is the final report for this project. We proposed to continue our work on extracting important results from the EUVE (Extreme UltraViolet Explorer) archive of lunar and jovian system observations. In particular, we planned to: (1) produce several monochromatic images of the Moon at the wavelengths of the brightest solar EUV emission lines; (2) search for evidence of soft X-ray emissions from the Moon and/or X-ray fluorescence at specific EUV wavelengths; (3) search for localized EUV and soft X-ray emissions associated with each of the Galilean satellites; (4) search for correlations between localized Io Plasma Torus (IPT) brightness and volcanic activity on Io; (5) search for soft X-ray emissions from Jupiter; and (6) determine the long term variability of He 58.4 nm emissions from Jupiter, and relate these to solar variability. However, the ADP review panel suggested that the work concentrate on the Jupiter/IPT observations, and provided half the requested funding. Thus we have performed no work on the first two tasks, and instead concentrated on the last three. In addition we used funds from this project to support reduction and analysis of EUVE observations of Venus. While this was not part of the original statement of work, it is entirely in keeping with extracting important results from EUVE solar system observations.

Probing the Production of Extreme-ultraviolet Late-phase Solar Flares Using the Model Enthalpy-based Thermal Evolution of Loops

NASA Astrophysics Data System (ADS)

Dai, Yu; Ding, Mingde

2018-04-01

Recent observations in extreme-ultraviolet (EUV) wavelengths reveal an EUV late phase in some solar flares that is characterized by a second peak in warm coronal emissions (∼3 MK) several tens of minutes to a few hours after the soft X-ray (SXR) peak. Using the model enthalpy-based thermal evolution of loops (EBTEL), we numerically probe the production of EUV late-phase solar flares. Starting from two main mechanisms of producing the EUV late phase, i.e., long-lasting cooling and secondary heating, we carry out two groups of numerical experiments to study the effects of these two processes on the emission characteristics in late-phase loops. In either of the two processes an EUV late-phase solar flare that conforms to the observational criteria can be numerically synthesized. However, the underlying hydrodynamic and thermodynamic evolutions in late-phase loops are different between the two synthetic flare cases. The late-phase peak due to a long-lasting cooling process always occurs during the radiative cooling phase, while that powered by a secondary heating is more likely to take place in the conductive cooling phase. We then propose a new method for diagnosing the two mechanisms based on the shape of EUV late-phase light curves. Moreover, from the partition of energy input, we discuss why most solar flares are not EUV late flares. Finally, by addressing some other factors that may potentially affect the loop emissions, we also discuss why the EUV late phase is mainly observed in warm coronal emissions.

EUV and Magnetic Activities Associated with Type-I Solar Radio Bursts

NASA Astrophysics Data System (ADS)

Li, C. Y.; Chen, Y.; Wang, B.; Ruan, G. P.; Feng, S. W.; Du, G. H.; Kong, X. L.

2017-06-01

Type-I bursts ( i.e. noise storms) are the earliest-known type of solar radio emission at the meter wavelength. They are believed to be excited by non-thermal energetic electrons accelerated in the corona. The underlying dynamic process and exact emission mechanism still remain unresolved. Here, with a combined analysis of extreme ultraviolet (EUV), radio and photospheric magnetic field data of unprecedented quality recorded during a type-I storm on 30 July 2011, we identify a good correlation between the radio bursts and the co-spatial EUV and magnetic activities. The EUV activities manifest themselves as three major brightening stripes above a region adjacent to a compact sunspot, while the magnetic field there presents multiple moving magnetic features (MMFs) with persistent coalescence or cancelation and a morphologically similar three-part distribution. We find that the type-I intensities are correlated with those of the EUV emissions at various wavelengths with a correlation coefficient of 0.7 - 0.8. In addition, in the region between the brightening EUV stripes and the radio sources there appear consistent dynamic motions with a series of bi-directional flows, suggesting ongoing small-scale reconnection there. Mainly based on the induced connection between the magnetic motion at the photosphere and the EUV and radio activities in the corona, we suggest that the observed type-I noise storms and the EUV brightening activities are the consequence of small-scale magnetic reconnection driven by MMFs. This is in support of the original proposal made by Bentley et al. ( Solar Phys. 193, 227, 2000).

Advanced manufacturing rules check (MRC) for fully automated assessment of complex reticle designs

NASA Astrophysics Data System (ADS)

Gladhill, R.; Aguilar, D.; Buck, P. D.; Dawkins, D.; Nolke, S.; Riddick, J.; Straub, J. A.

2005-11-01

Advanced electronic design automation (EDA) tools, with their simulation, modeling, design rule checking, and optical proximity correction capabilities, have facilitated the improvement of first pass wafer yields. While the data produced by these tools may have been processed for optimal wafer manufacturing, it is possible for the same data to be far from ideal for photomask manufacturing, particularly at lithography and inspection stages, resulting in production delays and increased costs. The same EDA tools used to produce the data can be used to detect potential problems for photomask manufacturing in the data. A production implementation of automated photomask manufacturing rule checking (MRC) is presented and discussed for various photomask lithography and inspection lines. This paper will focus on identifying data which may cause production delays at the mask inspection stage. It will be shown how photomask MRC can be used to discover data related problems prior to inspection, separating jobs which are likely to have problems at inspection from those which are not. Photomask MRC can also be used to identify geometries requiring adjustment of inspection parameters for optimal inspection, and to assist with any special handling or change of routing requirements. With this foreknowledge, steps can be taken to avoid production delays that increase manufacturing costs. Finally, the data flow implemented for MRC can be used as a platform for other photomask data preparation tasks.

EUV efficiency of a 6000-grooves per mm diffraction grating

NASA Technical Reports Server (NTRS)

Hurwitz, Mark; Bowyer, Stuart; Edelstein, Jerry; Harada, Tatsuo; Kita, Toshiaki

1990-01-01

In order to explore whether grooves ruled mechanically at a density of 6000 per mm can perform well at EUV wavelengths, a sample grating is measured with this density in an EUV calibration facility. Measurements are presented of the planar uniform line-space diffraction grating's efficiency and large-angle scattering.

A study of EUV emission from the O4f star Zeta Puppis

NASA Technical Reports Server (NTRS)

Waldron, Wayne L.; Vallerga, John

1995-01-01

Our 20 ks observation did not allow us to carry out our primary objective, i.e., to test the limitations of deeply embedded EUV and X-ray sources. However, it did provide a very useful constraint in our analysis of a newly acquired high S/N ROSAT PSPC X-ray spectrum of Zeta Pup. In addition, modifications to our stellar wind opacity code have been preformed to investigate the sensitivity of the EUV opacity energy range to different photospheric model flux inputs and different wind structures. These analyses provided the justification for a 140 ks follow up EUVE Cycle III observation of this star. We have recently been informed that our requested observation has been accepted as a Type 1 target for Cycle III. The remainder of this report focuses on the following: (1) a brief background on the status of X-ray emission from OB stars; (2) a discussion on the importance of EUV observations; (3) a discussion of our scientific objectives; and (4) a summary of our technical approach for our Cycle III observation (including the predicted EUV counts for various lines.)

Correlation of experimentally measured atomic scale properties of EUV photoresist to modeling performance: an exploration

NASA Astrophysics Data System (ADS)

Kandel, Yudhishthir; Chandonait, Jonathan; Melvin, Lawrence S.; Marokkey, Sajan; Yan, Qiliang; Grzeskowiak, Steven; Painter, Benjamin; Denbeaux, Gregory

2017-03-01

Extreme ultraviolet (EUV) lithography at 13.5 nm stands at the crossroads of next generation patterning technology for high volume manufacturing of integrated circuits. Photo resist models that form the part of overall pattern transform model for lithography play a vital role in supporting this effort. The physics and chemistry of these resists must be understood to enable the construction of accurate models for EUV Optical Proximity Correction (OPC). In this study, we explore the possibility of improving EUV photo-resist models by directly correlating the parameters obtained from experimentally measured atomic scale physical properties; namely, the effect of interaction of EUV photons with photo acid generators in standard chemically amplified EUV photoresist, and associated electron energy loss events. Atomic scale physical properties will be inferred from the measurements carried out in Electron Resist Interaction Chamber (ERIC). This study will use measured physical parameters to establish a relationship with lithographically important properties, such as line edge roughness and CD variation. The data gathered from these measurements is used to construct OPC models of the resist.

Availability of underlayer application to EUV process

NASA Astrophysics Data System (ADS)

Kosugi, Hitoshi; Fonseca, Carlos; Iwao, Fumiko; Marumoto, Hiroshi; Kim, Hyun-Woo; Cho, Kyoungyong; Park, Cheol-Hong; Park, Chang-Min; Na, Hai-Sub; Koh, Cha-Won; Cho, Hanku

2011-04-01

EUV lithography is one of the most promising technologies for the fabrication of beyond 30nm HP generation devices. However, it is well-known that EUV lithography still has significant challenges. A great concern is the change of resist material for EUV resist process. EUV resist material formulations will likely change from conventional-type materials. As a result, substrate dependency needs to be understood. TEL has reported that the simulation combined with experiments is a good way to confirm the substrate dependency. In this work the application of HMDS treatment and SiON introduction, as an underlayer, are studied to cause a footing of resist profile. Then, we applied this simulation technique to Samsung EUV process. We will report the benefit of this simulation work and effect of underlayer application. Regarding the etching process, underlayer film introduction could have significant issues because the film that should be etched off increases. For that purpose, thinner films are better for etching. In general, thinner films may have some coating defects. We will report the coating coverage performance and defectivity of ultra thin film coating.

Alternating phase-shifting masks: phase determination and impact of quartz defects--theoretical and experimental results

NASA Astrophysics Data System (ADS)

Griesinger, Uwe A.; Dettmann, Wolfgang; Hennig, Mario; Heumann, Jan P.; Koehle, Roderick; Ludwig, Ralf; Verbeek, Martin; Zarrabian, Mardjan

2002-07-01

In optical lithography balancing the aerial image of an alternating phase shifting mask (alt. PSM) is a major challenge. For the exposure wavelengths (currently 248nm and 193nm) an optimum etching method is necessary to overcome imbalance effects. Defects play an important role in the imbalances of the aerial image. In this contribution defects will be discussed by using the methodology of global phase imbalance control also for local imbalances which are a result of quartz defects. The effective phase error can be determined with an AIMS-system by measuring the CD width between the images of deep- and shallow trenches at different focus settings. The AIMS results are analyzed in comparison to the simulated and lithographic print results of the alternating structures. For the analysis of local aerial image imbalances it is necessary to investigate the capability of detecting these phase defects with state of the art inspection systems. Alternating PSMs containing programmed defects were inspected with different algorithms to investigate the capture rate of special phase defects in dependence on the defect size. Besides inspection also repair of phase defects is an important task. In this contribution we show the effect of repair on the optical behavior of phase defects. Due to the limited accuracy of the repair tools the repaired area still shows a certain local phase error. This error can be caused either by residual quartz material or a substrate damage. The influence of such repair induced phase errors on the aerial image were investigated.

Societal Impacts of Solar Electromagnetic Radiation

NASA Astrophysics Data System (ADS)

Lean, J. L.

2000-05-01

Changes in solar electromagnetic radiation, which occur continuously and at all wavelengths of the spectrum, can have significant societal impacts on a wide range of time scales. Detection of climate change and ozone depletion requires reliable specification of solar-induced processes that mask or exacerbate anthropogenic effects. Living with, and mitigating, climate change and ozone depletion has significant economic, habitat and political impacts of international extent. As an example, taxes to restrict carbon emission may cause undue economic stress if the role of greenhouse gases in global warming is incorrectly diagnosed. Ignoring solar-induced ozone changes in the next century may lead to incorrect assessment of the success of the Montreal Protocol in protecting the ozone layer by limiting the use of ozone-destroying chlorofluorocarbons. Societal infrastructure depends in many ways on space-based technological assets. Communications and navigation for commerce, industry, science and defense rely on satellite signals transmitted through, and reflected by, electrons in the ionosphere. Electron densities change in response to solar flares, and by orders of magnitude in response to EUV and X-ray flux variations during the Sun's 11-year activity cycle. Spacecraft and space debris experience enhanced drag on their orbits when changing EUV radiation causes upper atmosphere densities to increase. Especially affected are spacecraft and debris in lower altitude orbits, such as Iridium-type communication satellites, and the International Space Station (ISS). Proper specification of solar-induced fluctuations in the neutral upper atmosphere can, for example, aid in tracking the ISS and surrounding space debris, reducing the chance of ISS damage from collisions, and maximizing its operations. Aspects of solar electromagnetic radiation variability will be briefly illustrated on a range of time scales, with specific identification of the societal impacts of different spectral regions.

The EUVE Proposal Database

NASA Astrophysics Data System (ADS)

Christian, C. A.; Olson, E. C.

1993-01-01

The proposal database and scheduling system for the Extreme Ultraviolet Explorer is described. The proposal database has been implemented to take input for approved observations selected by the EUVE Peer Review Panel and output target information suitable for the scheduling system to digest. The scheduling system is a hybrid of the SPIKE program and EUVE software which checks spacecraft constraints, produces a proposed schedule and selects spacecraft orientations with optimal configurations for acquiring star trackers, etc. This system is used to schedule the In Orbit Calibration activities that took place this summer, following the EUVE launch in early June 1992. The strategy we have implemented has implications for the selection of approved targets, which have impacted the Peer Review process. In addition, we will discuss how the proposal database, founded on Sybase, controls the processing of EUVE Guest Observer data.

Spectroscopy and Photometry of EUVE J1429-38.0:An Eclipsing Magnetic Cataclysmic Variable

NASA Astrophysics Data System (ADS)

Howell, Steve B.; Craig, Nahide; Roberts, Bryce; McGee, Paddy; Sirk, Martin

1997-06-01

EUVE J1429-38.0 was originally discovered as a variable source by the Extreme Ultraviolet Explorer (EUVE) satellite. We present new optical observations which unambiguously confirm this star to be an eclipsing magnetic system with an orbital period of 4() h 46() m. The photometric data are strongly modulated by ellipsoidal variations during low states which allow a system inclination of near 80 degrees to be determined. Our time-resolved optical spectra, which cover only about one-third of the orbital cycle, indicate the clear presence of a gas stream. During high states, EUVE J1429-38.0 shows ~ 1 mag deep eclipses and the apparent formation of a partial accretion disk. EUVE J1429-38.0 presents the observer with properties of both the AM Herculis and the DQ Herculis types of magnetic cataclysmic variable.

Pattern centric design based sensitive patterns and process monitor in manufacturing

NASA Astrophysics Data System (ADS)

Hsiang, Chingyun; Cheng, Guojie; Wu, Kechih

2017-03-01

When design rule is mitigating to smaller dimension, process variation requirement is tighter than ever and challenges the limits of device yield. Masks, lithography, etching and other processes have to meet very tight specifications in order to keep defect and CD within the margins of the process window. Conventionally, Inspection and metrology equipments are utilized to monitor and control wafer quality in-line. In high throughput optical inspection, nuisance and review-classification become a tedious labor intensive job in manufacturing. Certain high-resolution SEM images are taken to validate defects after optical inspection. These high resolution SEM images catch not only optical inspection highlighted point, also its surrounding patterns. However, this pattern information is not well utilized in conventional quality control method. Using this complementary design based pattern monitor not only monitors and analyzes the variation of patterns sensitivity but also reduce nuisance and highlight defective patterns or killer defects. After grouping in either single or multiple layers, systematic defects can be identified quickly in this flow. In this paper, we applied design based pattern monitor in different layers to monitor process variation impacts on all kinds of patterns. First, the contour of high resolutions SEM image is extracted and aligned to design with offset adjustment and fine alignment [1]. Second, specified pattern rules can be applied on design clip area, the same size as SEM image, and form POI (pattern of interest) areas. Third, the discrepancy of contour and design measurement at different pattern types in measurement blocks. Fourth, defective patterns are reported by discrepancy detection criteria and pattern grouping [4]. Meanwhile, reported pattern defects are ranked by number and severity by discrepancy. In this step, process sensitive high repeatable systematic defects can be identified quickly Through this design based process pattern monitor method, most of optical inspection nuisances can be filtered out at contour to design discrepancy measurement. Daily analysis results are stored at database as reference to compare with incoming data. Defective pattern library contains existing and known systematic defect patterns which help to catch and identify new pattern defects or process impacts. On the other hand, this defect pattern library provides extra valuable information for mask, pattern and defects verification, inspection care area generation, further OPC fix and process enhancement and investigation.

LPP-EUV light source for HVM lithography

NASA Astrophysics Data System (ADS)

Saito, T.; Ueno, Y.; Yabu, T.; Kurosawa, A.; Nagai, S.; Yanagida, T.; Hori, T.; Kawasuji, Y.; Abe, T.; Kodama, T.; Nakarai, H.; Yamazaki, T.; Mizoguchi, H.

2017-01-01

We have been developing a laser produced plasma extremely ultra violet (LPP-EUV) light source for a high volume manufacturing (HVM) semiconductor lithography. It has several unique technologies such as the high power short pulse carbon dioxide (CO2) laser, the short wavelength solid-state pre-pulse laser and the debris mitigation technology with the magnetic field. This paper presents the key technologies for a high power LPP-EUV light source. We also show the latest performance data which is 188W EUV power at intermediate focus (IF) point with 3.7% conversion efficiency (CE) at 100 kHz.

EUV Irradiance Inputs to Thermospheric Density Models: Open Issues and Path Forward

NASA Astrophysics Data System (ADS)

Vourlidas, A.; Bruinsma, S.

2018-01-01

One of the objectives of the NASA Living With a Star Institute on "Nowcasting of Atmospheric Drag for low Earth orbit (LEO) Spacecraft" was to investigate whether and how to increase the accuracy of atmospheric drag models by improving the quality of the solar forcing inputs, namely, extreme ultraviolet (EUV) irradiance information. In this focused review, we examine the status of and issues with EUV measurements and proxies, discuss recent promising developments, and suggest a number of ways to improve the reliability, availability, and forecast accuracy of EUV measurements in the next solar cycle.

The patterning center of excellence (CoE): an evolving lithographic enablement model

NASA Astrophysics Data System (ADS)

Montgomery, Warren; Chun, Jun Sung; Liehr, Michael; Tittnich, Michael

2015-03-01

As EUV lithography moves toward high-volume manufacturing (HVM), a key need for the lithography materials makers is access to EUV photons and imaging. The SEMATECH Resist Materials Development Center (RMDC) provided a solution path by enabling the Resist and Materials companies to work together (using SUNY Polytechnic Institute's Colleges of Nanoscale Science and Engineering (SUNY Poly CNSE) -based exposure systems), in a consortium fashion, in order to address the need for EUV photons. Thousands of wafers have been processed by the RMDC (leveraging the SUNY Poly CNSE/SEMATECH MET, SUNY Poly CNSE Alpha Demo Tool (ADT) and the SEMATECH Lawrence Berkeley MET) allowing many of the questions associated with EUV materials development to be answered. In this regard the activities associated with the RMDC are continuing. As the major Integrated Device Manufacturers (IDMs) have continued to purchase EUV scanners, Materials companies must now provide scanner based test data that characterizes the lithography materials they are producing. SUNY Poly CNSE and SEMATECH have partnered to evolve the RMDC into "The Patterning Center of Excellence (CoE)". The new CoE leverages the capability of the SUNY Poly CNSE-based full field ASML 3300 EUV scanner and combines that capability with EUV Microexposure (MET) systems resident in the SEMATECH RMDC to create an integrated lithography model which will allow materials companies to advance materials development in ways not previously possible.

SDO/AIA AND HINODE/EIS OBSERVATIONS OF INTERACTION BETWEEN AN EUV WAVE AND ACTIVE REGION LOOPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Liheng; Zhang, Jun; Li, Ting

2013-09-20

We present detailed analysis of an extreme-ultraviolet (EUV) wave and its interaction with active region (AR) loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly and the Hinode EUV Imaging Spectrometer (EIS). This wave was initiated from AR 11261 on 2011 August 4 and propagated at velocities of 430-910 km s{sup –1}. It was observed to traverse another AR and cross over a filament channel on its path. The EUV wave perturbed neighboring AR loops and excited a disturbance that propagated toward the footpoints of these loops. EIS observations of AR loops revealed that at the time of the wavemore » transit, the original redshift increased by about 3 km s{sup –1}, while the original blueshift decreased slightly. After the wave transit, these changes were reversed. When the EUV wave arrived at the boundary of a polar coronal hole, two reflected waves were successively produced and part of them propagated above the solar limb. The first reflected wave above the solar limb encountered a large-scale loop system on its path, and a secondary wave rapidly emerged 144 Mm ahead of it at a higher speed. These findings can be explained in the framework of a fast-mode magnetosonic wave interpretation for EUV waves, in which observed EUV waves are generated by expanding coronal mass ejections.« less

Kr photoionized plasma induced by intense extreme ultraviolet pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartnik, A., E-mail: andrzej.bartnik@wat.edu.pl; Wachulak, P.; Fiedorowicz, H.

Irradiation of any gas with an intense EUV (extreme ultraviolet) radiation beam can result in creation of photoionized plasmas. The parameters of such plasmas can be significantly different when compared with those of the laser produced plasmas (LPP) or discharge plasmas. In this work, the photoionized plasmas were created in a krypton gas irradiated using an LPP EUV source operating at a 10 Hz repetition rate. The Kr gas was injected into the vacuum chamber synchronously with the EUV radiation pulses. The EUV beam was focused onto a Kr gas stream using an axisymmetrical ellipsoidal collector. The resulting low temperature Krmore » plasmas emitted electromagnetic radiation in the wide spectral range. The emission spectra were measured either in the EUV or an optical range. The EUV spectrum was dominated by emission lines originating from Kr III and Kr IV ions, and the UV/VIS spectra were composed from Kr II and Kr I lines. The spectral lines recorded in EUV, UV, and VIS ranges were used for the construction of Boltzmann plots to be used for the estimation of the electron temperature. It was shown that for the lowest Kr III and Kr IV levels, the local thermodynamic equilibrium (LTE) conditions were not fulfilled. The electron temperature was thus estimated based on Kr II and Kr I species where the partial LTE conditions could be expected.« less

Nanoplasmonic generation of ultrashort EUV pulses

NASA Astrophysics Data System (ADS)

Choi, Joonhee; Lee, Dong-Hyub; Han, Seunghwoi; Park, In-Yong; Kim, Seungchul; Kim, Seung-Woo

2012-10-01

Ultrashort extreme-ultraviolet (EUV) light pulses are an important tool for time-resolved pump-probe spectroscopy to investigate the ultrafast dynamics of electrons in atoms and molecules. Among several methods available to generate ultrashort EUV light pulses, the nonlinear frequency upconversion process of high-harmonic generation (HHG) draws attention as it is capable of producing coherent EUV pulses with precise control of burst timing with respect to the driving near-infrared (NIR) femtosecond laser. In this report, we present and discuss our recent experimental data obtained by the plasmon-driven HHG method that generate EUV radiation by means of plasmonic nano-focusing of NIR femtosecond pulses. For experiment, metallic waveguides having a tapered hole of funnel shape inside were fabricated by adopting the focused-ion-beam process on a micro-cantilever substrate. The plasmonic field formed within the funnelwaveguides being coupled with the incident femtosecond pulse permitted intensity enhancement by a factor of ~350, which creates a hot spot of sub-wavelength size with intensities strong enough for HHG. Experimental results showed that with injection of noble gases into the funnel-waveguides, EUV radiation is generated up to wavelengths of 32 nm and 29.6 nm from Ar and Ne gas atoms, respectively. Further, it was observed that lower-order EUV harmonics are cut off in the HHG spectra by the tiny exit aperture of the funnel-waveguide.

Kr photoionized plasma induced by intense extreme ultraviolet pulses

NASA Astrophysics Data System (ADS)

Bartnik, A.; Wachulak, P.; Fiedorowicz, H.; Skrzeczanowski, W.

2016-04-01

Irradiation of any gas with an intense EUV (extreme ultraviolet) radiation beam can result in creation of photoionized plasmas. The parameters of such plasmas can be significantly different when compared with those of the laser produced plasmas (LPP) or discharge plasmas. In this work, the photoionized plasmas were created in a krypton gas irradiated using an LPP EUV source operating at a 10 Hz repetition rate. The Kr gas was injected into the vacuum chamber synchronously with the EUV radiation pulses. The EUV beam was focused onto a Kr gas stream using an axisymmetrical ellipsoidal collector. The resulting low temperature Kr plasmas emitted electromagnetic radiation in the wide spectral range. The emission spectra were measured either in the EUV or an optical range. The EUV spectrum was dominated by emission lines originating from Kr III and Kr IV ions, and the UV/VIS spectra were composed from Kr II and Kr I lines. The spectral lines recorded in EUV, UV, and VIS ranges were used for the construction of Boltzmann plots to be used for the estimation of the electron temperature. It was shown that for the lowest Kr III and Kr IV levels, the local thermodynamic equilibrium (LTE) conditions were not fulfilled. The electron temperature was thus estimated based on Kr II and Kr I species where the partial LTE conditions could be expected.

Solar Demon: near real-time Flare, Dimming and EUV wave monitoring

NASA Astrophysics Data System (ADS)

Kraaikamp, Emil; Verbeeck, Cis

Dimmings and EUV waves have been observed routinely in EUV images since 1996. They are closely associated with coronal mass ejections (CMEs), and therefore provide useful information for early space weather alerts. On the one hand, automatic detection and characterization of dimmings and EUV waves can be used to gain better understanding of the underlying physical mechanisms. On the other hand, every dimming and EUV wave provides extra information on the associated front side CME, and can improve estimates of the geo-effectiveness and arrival time of the CME. Solar Demon has been designed to detect and characterize dimmings, EUV waves, as well as solar flares in near real-time on Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) data. The detection modules are running continuously at the Royal Observatory of Belgium on both quick-look data, as well as synoptic science data. The output of Solar Demon can be accessed in near real-time on the Solar Demon website, and includes images, movies, light curves, and the numerical evolution of several parameters. Solar Demon is the result of collaboration between the FP7 projects AFFECTS and COMESEP. Flare detections of Solar Demon are integrated into the COMESEP alert system. Here we present the Solar Demon detection algorithms and their output. We will show several interesting flare, dimming and EUV wave events, and present general statistics of the detections made so far during solar cycle 24.

Development of Mask Materials for EUVL

NASA Astrophysics Data System (ADS)

Heckle, Christine; Hrdina, Kenneth E.; Ackerman, Bradford G.; Navan, David W.

2002-12-01

Though the Semiconductor market is soft, the technology that drives it continues to march on. Corning has supplied the semiconductor market through two generations of lithography with KrF and ArF grade HPFS Glass; the established excellence will continue with the supply of CaF2 for 157nm and ULE Glass for 13nm. ULE Glass is a low expansion silicate glass that has historically been used for ground and spaced based telescope mirrors such as Gemini and Hubble. Industry experts have now identified ULE Glass as a material of choice for EUVL applications; but with new opportunities come new hurdles, and ULE Glass will need to be improved in order to meet the challenges of EUVL. The purpose of this presentation is to give the audience a general update of Corning's ULE Glass improvement effort for EUVL, with focus on EUV photomask requirements; it will include an overview of key ULE Glass properties, improvements that have been made, and a road map of work to be done.

EUV mirror based absolute incident flux detector

DOEpatents

Berger, Kurt W.

2004-03-23

A device for the in-situ monitoring of EUV radiation flux includes an integrated reflective multilayer stack. This device operates on the principle that a finite amount of in-band EUV radiation is transmitted through the entire multilayer stack. This device offers improvements over existing vacuum photo-detector devices since its calibration does not change with surface contamination.

Calibration techniques and results in the soft X-ray and extreme ultraviolet for components of the Extreme Ultraviolet Explorer Satellite

NASA Technical Reports Server (NTRS)

Malina, Roger F.; Jelinsky, Patrick; Bowyer, Stuart

1986-01-01

The calibration facilities and techniques for the Extreme Ultraviolet Explorer (EUVE) from 44 to 2500 A are described. Key elements include newly designed radiation sources and a collimated monochromatic EUV beam. Sample results for the calibration of the EUVE filters, detectors, gratings, collimators, and optics are summarized.

Exploring EUV Spicules Using 304 Angstrom He II Data from SDO AIA

NASA Technical Reports Server (NTRS)

Snyder, Ian R.; Sterling, Alphonse C.; Falconer, David A.; Moore, Ron L.

2014-01-01

We present results from a statistical study of He II 304 Angstrom Extreme Ultraviolet (EUV) spicules at the limb of the Sun. We also measured properties of one macrospicule; macrospicules are longer than most spicules, and much broader in width than spicules. We use high-cadence (12 second) and high-resolution (0.6 arcseconds pixels) resolution data from the Atmospheric Imaging Array (AIA) instrument on the Solar Dynamic Observatory (SDO). All of the observed events occurred near the solar north pole, where quiet Sun or coronal hole environments ensued. We examined the maximum lengths, maximum rise velocities, and lifetimes of 33 Extreme Ultraviolet (EUV) spicules and the macrospicule. For the bulk of the Extreme Ultraviolet (EUV) spicules these quantities are, respectively, approximately 10,000-40,000 kilometers, 20-100 kilometers per second, and approximately 100- approximately 1000 seconds. For the macrospicule the corresponding quantities were respectively approximately 60,000 kilometers, approximately 130 kilometers per second, approximately 1800 seconds, which is typical of macrospicules measured by other workers. Therefore macrospicules are taller, longer-lived, and faster than most Extreme Ultraviolet (EUV) spicules. The rise profiles of both the spicules and the macrospicules match well a second-order ("parabolic" ) trajectory, although the acceleration was often weaker than that of solar gravity in the profiles fitted to the trajectories. Our macrospicule also had an obvious brightening at its base at birth, while such brightening was not apparent for the Extreme Ultraviolet (EUV) spicules. Most of the Extreme Ultraviolet (EUV) spicules remained visible during their descent back to the solar surface, although a small percentage of the spicules and the macrospicule faded out before falling back to the surface. Our sample of macrospicules is not yet large enough to determine whether their initiation mechanism is identical to that of Extreme Ultraviolet (EUV) spicules.

Controlling contamination in Mo/Si multilayer mirrors by Si surface capping modifications

NASA Astrophysics Data System (ADS)

Malinowski, Michael E.; Steinhaus, Chip; Clift, W. Miles; Klebanoff, Leonard E.; Mrowka, Stanley; Soufli, Regina

2002-07-01

The performance of Mo/Si multilayer mirrors (MLMs) used to reflect UV (EUV) radiation in an EUV + hydrocarbon (NC) vapor environment can be improved by optimizing the silicon capping layer thickness on the MLM in order to minimize the initial buildup of carbon on MLMs. Carbon buildup is undesirable since it can absorb EUV radiation and reduce MLM reflectivity. A set of Mo/Si MLMs deposited on Si wafers was fabricated such that each MLM had a different Si capping layer thickness ranging form 2 nm to 7 nm. Samples from each MLM wafer were exposed to a combination of EUV light + (HC) vapors at the Advanced Light Source (ALS) synchrotron in order to determine if the Si capping layer thickness affected the carbon buildup on the MLMs. It was found that the capping layer thickness had a major influence on this 'carbonizing' tendency, with the 3 nm layer thickness providing the best initial resistance to carbonizing and accompanying EUV reflectivity loss in the MLM. The Si capping layer thickness deposited on a typical EUV optic is 4.3 nm. Measurements of the absolute reflectivities performed on the Calibration and Standards beamline at the ALS indicated the EUV reflectivity of the 3 nm-capped MLM was actually slightly higher than that of the normal, 4 nm Si-capped sample. These results show that he use of a 3 nm capping layer represents an improvement over the 4 nm layer since the 3 nm has both a higher absolute reflectivity and better initial resistance to carbon buildup. The results also support the general concept of minimizing the electric field intensity at the MLM surface to minimize photoelectron production and, correspondingly, carbon buildup in a EUV + HC vapor environment.

Free-electron laser emission architecture impact on extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

Hosler, Erik R.; Wood, Obert R.; Barletta, William A.

2017-10-01

Laser-produced plasma (LPP) EUV sources have demonstrated ˜125 W at customer sites, establishing confidence in EUV lithography (EUVL) as a viable manufacturing technology. However, for extension to the 3-nm technology node and beyond, existing scanner/source technology must enable higher-NA imaging systems (requiring increased resist dose and providing half-field exposures) and/or EUV multipatterning (requiring increased wafer throughput proportional to the number of exposure passes). Both development paths will require a substantial increase in EUV source power to maintain the economic viability of the technology, creating an opportunity for free-electron laser (FEL) EUV sources. FEL-based EUV sources offer an economic, high-power/single-source alternative to LPP EUV sources. Should FELs become the preferred next-generation EUV source, the choice of FEL emission architecture will greatly affect its operational stability and overall capability. A near-term industrialized FEL is expected to utilize one of the following three existing emission architectures: (1) self-amplified spontaneous emission, (2) regenerative amplifier, or (3) self-seeding. Model accelerator parameters are put forward to evaluate the impact of emission architecture on FEL output. Then, variations in the parameter space are applied to assess the potential impact to lithography operations, thereby establishing component sensitivity. The operating range of various accelerator components is discussed based on current accelerator performance demonstrated at various scientific user facilities. Finally, comparison of the performance between the model accelerator parameters and the variation in parameter space provides a means to evaluate the potential emission architectures. A scorecard is presented to facilitate this evaluation and provides a framework for future FEL design and enablement for EUVL applications.

Evidence for a New Class of Extreme Ultraviolet Sources

NASA Technical Reports Server (NTRS)

Maoz, Dan; Ofek, Eran O.; Shemi, Amotz

1997-01-01

Most of the sources detected in the extreme ultraviolet (EUV; 100-600 A) by the ROSAT/WFC and EUVE all-sky surveys have been identified with active late-type stars and hot white dwarfs that are near enough to the Earth to escape absorption by interstellar gas. However, about 15 per cent of EUV sources are as yet unidentified with any optical counterparts. We examine whether the unidentified EUV sources may consist of the same population of late-type stars and white dwarfs. We present B and R photometry of stars in the fields of seven of the unidentified EUV sources. We detect in the optical the entire main-sequence and white dwarf population out to the greatest distances where they could still avoid absorption. We use color-magnitude diagrams to demonstrate that, in most of the fields, none of the observed stars has the colours and magnitudes of late-type dwarfs at distances less than 100 pc. Similarly, none of the observed stars is a white dwarf within 500 pc that is hot enough to be a EUV emitter. The unidentified EUV sources we study are not detected in X-rays, while cataclysmic variables, X-ray binaries, and active galactic nuclei generally are. We conclude that some of the EUV sources may be a new class of nearby objects, which are either very faint at optical bands or which mimic the colours and magnitudes of distant late-type stars or cool white dwarfs. One candidate for optically faint objects is isolated old neutron stars, slowly accreting interstellar matter. Such neutron stars are expected to be abundant in the Galaxy, and have not been unambiguously detected.

Method of fabricating reflection-mode EUV diffraction elements

DOEpatents

Naulleau, Patrick P.

2002-01-01

Techniques for fabricating a well-controlled, quantized-level, engineered surface that serves as substrates for EUV reflection multilayer overcomes problems associated with the fabrication of reflective EUV diffraction elements. The technique when employed to fabricate an EUV diffraction element that includes the steps of: (a) forming an etch stack comprising alternating layers of first and second materials on a substrate surface where the two material can provide relative etch selectivity; (b) creating a relief profile in the etch stack wherein the relief profile has a defined contour; and (c) depositing a multilayer reflection film over the relief profile wherein the film has an outer contour that substantially matches that of the relief profile. For a typical EUV multilayer, if the features on the substrate are larger than 50 nm, the multilayer will be conformal to the substrate. Thus, the phase imparted to the reflected wavefront will closely match that geometrically set by the surface height profile.

EUV spectroscopy of highly charged high Z ions in the Large Helical Device plasmas

NASA Astrophysics Data System (ADS)

Suzuki, C.; Koike, F.; Murakami, I.; Tamura, N.; Sudo, S.; Sakaue, H. A.; Nakamura, N.; Morita, S.; Goto, M.; Kato, D.; Nakano, T.; Higashiguchi, T.; Harte, C. S.; OʼSullivan, G.

2014-11-01

We present recent results on the extreme ultraviolet (EUV) spectroscopy of highly charged high Z ions in plasmas produced in the Large Helical Device (LHD) at the National Institute for Fusion Science. Tungsten, bismuth and lanthanide elements have recently been studied in the LHD in terms of their importance in fusion research and EUV light source development. In relatively low temperature plasmas, quasicontinuum emissions from open 4d or 4f subshell ions are predominant in the EUV region, while the spectra tend to be dominated by discrete lines from open 4s or 4p subshell ions in higher temperature plasmas. Comparative analyses using theoretical calculations and charge-separated spectra observed in an electron beam ion trap have been performed to achieve better agreement with the spectra measured in the LHD. As a result, databases on Z dependence of EUV spectra in plasmas have been widely extended.

The Nature of the Flaring EUVE Companion to HD 43162

NASA Technical Reports Server (NTRS)

Kulkarni, Shrinivas R.

2005-01-01

The purpose of our program was to observe and characterize the companion to HD 43162, EUVE J0614-2354, which (serendipitously) experienced an enormous flare event during our EUVE observation of HD 43162, one of the nearby solar analogs that we observed during our survey of this population. Our observation was carried out and the data have been received and reduced. We are able to identify EUVE J0614-2354 in both the X-ray (EPIC MOS + PN) and the UV (OM) data, which provides a sub-arcsecond position for this source. Our findings are consistent with the analysis of Christian et al. (2003a,b), who identify EUVE J0614-2354 with a coronally-active M-dwarf star at distance d = 15 plus or minus 5pc. The X-ray spectrum from the EPIC data are also consistent with this identification.

Hemispherical Nature of EUV Shocks Revealed by SOHO, STEREO, and SDO Observations

NASA Technical Reports Server (NTRS)

Gopalswamy, Natchimuthuk; Nitta, N.; Akiyama, S.; Makela, P.; Yashiro, S.

2011-01-01

EUV wave transients associated with type II radio bursts are manifestation of CME-driven shocks in the solar corona. We use recent EUV wave observations from SOHO, STEREO, and SDO for a set of CMEs to show that the EUV transients have a spherical shape in the inner corona. We demonstrate this by showing that the radius of the EUV transient on the disk observed by one instrument is approximately equal to the height of the wave above the solar surface in an orthogonal view provided by another instrument. The study also shows that the CME-driven shocks often form very low in the corona at a heliocentric distance of 1.2 Rs, even smaller than the previous estimates from STEREO/CORl data (Gopalswamy et aI., 2009, Solar Phys. 259, 227). These results have important implications for the acceleration of solar energetic particles by CMEs

Diffractive optics for quasi-direct space-to-time pulse shaping.

PubMed

Mínguez-Vega, Gladys; Mendoza-Yero, Omel; Lancis, Jesús; Gisbert, Rafael; Andrés, Pedro

2008-10-13

The strong chromatic behavior associated with a conventional diffractive lens is fully exploited to propose a novel optical device for pulse shaping in the femtosecond regime. This device consists of two optical elements: a spatially patterned circularly symmetric mask and a kinoform diffractive lens, which are facing each other. The system performs a mapping between the spatial position of the masking function expressed in the squared radial coordinate and the temporal position in the output waveform. This space-to-time conversion occurs at the chromatic focus of the diffractive lens, and makes it possible to tailor the output central wavelength along the axial location of the output point. Inspection of the validity of our device is performed by means of computer simulations involving the generation of femtosecond optical packets.

Inline detection of Chrome degradation on binary 193nm photomasks

NASA Astrophysics Data System (ADS)

Dufaye, Félix; Sippel, Astrid; Wylie, Mark; García-Berríos, Edgardo; Crawford, Charles; Hess, Carl; Sartelli, Luca; Pogliani, Carlo; Miyashita, Hiroyuki; Gough, Stuart; Sundermann, Frank; Brochard, Christophe

2013-09-01

193nm binary photomasks are still used in the semiconductor industry for the lithography of some critical layers for the nodes 90nm and 65nm, with high volumes and over long periods. However, these 193nm binary photomasks can be impacted by a phenomenon of chrome oxidation leading to critical dimensions uniformity (CDU) degradation with a pronounced radial signature. If not detected early enough, this CDU degradation may cause defectivity issues and lower yield on wafers. Fortunately, a standard cleaning and repellicle service at the mask shop has been demonstrated as efficient to remove the grown materials and get the photomask CD back on target.Some detection methods have been already described in literature, such as wafer CD intrafield monitoring (ACLV), giving reliable results but also consuming additional SEM time with less precision than direct photomask measurement. In this paper, we propose another approach, by monitoring the CDU directly on the photomask, concurrently with defect inspection for regular requalification to production for wafer fabs. For this study, we focused on a Metal layer in a 90nm technology node. Wafers have been exposed with production conditions and then measured by SEM-CD. Afterwards, this photomask has been measured with a SEM-CD in mask shop and also inspected on a KLA-Tencor X5.2 inspection system, with pixels 125 and 90nm, to evaluate the Intensity based Critical Dimension Uniformity (iCDU) option. iCDU was firstly developed to provide feed-forward CDU maps for scanner intrafield corrections, from arrayed dense structures on memory photomasks. Due to layout complexity and differing feature types, CDU monitoring on logic photomasks used to pose unique challenges.The selection of suitable feature types for CDU monitoring on logic photomasks is no longer an issue, since the transmitted intensity map gives all the needed information, as shown in this paper. In this study, the photomask was heavily degraded after more than 18,000 300mm wafers exposed and the cleaning brought it back almost to its original state after manufacture. Wafer CD, photomask CD and iCDU results can be compared, before and after a standard mask shop cleaning. Measurement points have be chosen in logic areas and SRAM areas, so that their respective behaviours can be studied separately. Transmitted maps before and after cleaning were analysed in terms of CD shift and CDU degradation. The delta map shows a nice correlation with photomask CD shift. iCDU demonstrated the capability to detect a reliable CD range degradation of 5nm on photomask by a comparison between a reference inspection and the current inspection. Die to die inspection mode provides also valuable data, highlighting the degraded chrome sidewalls, more in the photomask centre than on the edges. Ultimately, these results would enable to trigger the preventive cleanings rather than on predefined thresholds. The expected gains for wafer fabs are cost savings (adapted cleanings frequency), increased photomask availability for production, longer photomask lifetime, no additional SEM time neither for photomask nor on wafer.

EUV wavefront metrology system in EUVA

NASA Astrophysics Data System (ADS)

Hasegawa, Takayuki; Ouchi, Chidane; Hasegawa, Masanobu; Kato, Seima; Suzuki, Akiyoshi; Sugisaki, Katsumi; Murakami, Katsuhiko; Saito, Jun; Niibe, Masahito

2004-05-01

An Experimental extreme ultraviolet (EUV) interferometer (EEI) using an undulator as a light source was installed in New SUBARU synchrotron facility at Himeji Institute of Technology (HIT). The EEI can evaluate the five metrology methods reported before. (1) A purpose of the EEI is to determine the most suitable method for measuring the projection optics of EUV lithography systems for mass production tools.

The extreme ultraviolet explorer archive

NASA Astrophysics Data System (ADS)

Polomski, E.; Drake, J. J.; Dobson, C.; Christian, C.

1993-09-01

The Extreme Ultrviolet Explorer (EUVE) public archive was created to handle the storage, maintenance, and distribution of EUVE data and ancillary documentation, information, and software. Access to the archive became available to the public on July 17, 1992, only 40 days after the launch of the EUVE satellite. A brief overview of the archive's contents and the various methods of access will be described.

EUV Coronal Waves: Atmospheric and Heliospheric Connections and Energetics

NASA Astrophysics Data System (ADS)

Patsourakos, S.

2015-12-01

Since their discovery in late 90's by EIT on SOHO, the study EUV coronal waves has been a fascinating andfrequently strongly debated research area. While it seems as ifan overall consensus has been reached about the nurture and nature of this phenomenon,there are still several important questions regarding EUV waves. By focusing on the most recentobservations, we will hereby present our current understanding about the nurture and nature of EUV waves,discuss their connections with other atmospheric and heliospheric phenomena (e.g.,flares and CMEs, Moreton waves, coronal shocks, coronal oscillations, SEP events) and finallyassess their possible energetic contribution to the overall budget of relatederuptive phenomena.

Molecular organometallic resists for EUV (MORE): Reactivity as a function of metal center (Bi, Sb, Te and Sn)

NASA Astrophysics Data System (ADS)

Sitterly, Jacob; Murphy, Michael; Grzeskowiak, Steven; Denbeaux, Greg; Brainard, Robert L.

2018-03-01

This paper describes the photoreactivity of six organometallic complexes of the type PhnMX2 containing bismuth, antimony and tellurium, where n = 3 for bismuth and antimony and n = 2 for tellurium, and where X = acetate (O2CCH3) or pivalate (O2CC(CH3)3). These compounds were exposed to EUV light to monitor photodecomposition via in situ mass spectral analysis of the primary outgassing products of CO2, benzene and phenol. This paper explores the effect of metal center and carboxylate ligand on the EUV reactivity of these EUV photoresists.

Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chai, Kil-Byoung; Bellan, Paul M.

2013-12-15

An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 10{sup 6} frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs.

EUV spectroscopy of high-redshift x-ray objects

NASA Astrophysics Data System (ADS)

Kowalski, M. P.; Wolff, M. T.; Wood, K. S.; Barbee, T. W., Jr.; Barstow, M. A.

2010-07-01

As astronomical observations are pushed to cosmological distances (z>3) the spectral energy distributions of X-ray objects, AGN for example, will be redshifted into the EUV waveband. Consequently, a wealth of critical spectral diagnostics, provided by, for example, the Fe L-shell complex and the O VII/VIII lines, will be lost to future planned X-ray missions (e.g., IXO, Gen-X) if operated at traditional X-ray energies. This opens up a critical gap in performance located at short EUV wavelengths, where critical X-ray spectral transitions occur in high-z objects. However, normal-incidence multilayer-grating technology, which performs best precisely at such wavelengths, together with advanced nanolaminate replication techniques have been developed and are now mature to the point where advanced EUV instrument designs with performance complementary to IXO and Gen-X are practical. Such EUV instruments could be flown either independently or as secondary instruments on these X-ray missions. We present here a critical examination of the limits placed on extragalactic EUV measurements by ISM absorption, the range where high-z measurements are practical, and the requirements this imposes on next-generation instrument designs. We conclude with a discussion of a breakthrough technology, nanolaminate replication, which enables such instruments.

EUV tools: hydrogen gas purification and recovery strategies

NASA Astrophysics Data System (ADS)

Landoni, Cristian; Succi, Marco; Applegarth, Chuck; Riddle Vogt, Sarah

2015-03-01

The technological challenges that have been overcome to make extreme ultraviolet lithography (EUV) a reality have been enormous1. This vacuum driven technology poses significant purity challenges for the gases employed for purging and cleaning the scanner EUV chamber and source. Hydrogen, nitrogen, argon and ultra-high purity compressed dry air (UHPCDA) are the most common gases utilized at the scanner and source level. Purity requirements are tighter than for previous technology node tools. In addition, specifically for hydrogen, EUV tool users are facing not only gas purity challenges but also the need for safe disposal of the hydrogen at the tool outlet. Recovery, reuse or recycling strategies could mitigate the disposal process and reduce the overall tool cost of operation. This paper will review the types of purification technologies that are currently available to generate high purity hydrogen suitable for EUV applications. Advantages and disadvantages of each purification technology will be presented. Guidelines on how to select the most appropriate technology for each application and experimental conditions will be presented. A discussion of the most common approaches utilized at the facility level to operate EUV tools along with possible hydrogen recovery strategies will also be reported.

On the Absence of EUV Emission from Comet C/2012 S1 (ISON)

NASA Technical Reports Server (NTRS)

Bryans, Paul; Pesnell, W. Dean

2016-01-01

When the sungrazing comet C2012 S1 (ISON) made its perihelion passage within two solar radii of the Sun's surface, it was expected to be a bright emitter at extreme ultraviolet (EUV) wavelengths. However, despite solar EUV telescopes repointing to track the orbit of the comet, no emission was detected. This null result is interesting in its own right, offering the possibility of placing limits on the size and composition of the nucleus. We explain the lack of detection by considering the properties of the comet and the solar atmosphere that determine the intensity of EUV emission from sungrazing comets. By comparing these properties with those of sungrazing comet C2011 W3 (Lovejoy), which did emit in the EUV, we conclude that the primary factor resulting in non-detectable EUV emission from C2012 S1 (ISON) was an insufficiently large nucleus. We conclude that the radius of C2012 S1 (ISON) was at least a factor of four less than that of C2011 W3 (Lovejoy). This is consistent with white-light observations in the days before perihelion that suggested the comet was dramatically reducing in size on approach.

Optical element for full spectral purity from IR-generated EUV light sources

NASA Astrophysics Data System (ADS)

van den Boogaard, A. J. R.; Louis, E.; van Goor, F. A.; Bijkerk, F.

2009-03-01

Laser produced plasma (LLP) sources are generally considered attractive for high power EUV production in next generation lithography equipment. Such plasmas are most efficiently excited by the relatively long, infrared wavelengths of CO2-lasers, but a significant part of the rotational-vibrational excitation lines of the CO2 radiation will be backscattered by the plasma's critical density surface and consequently will be present as parasitic radiation in the spectrum of such sources. Since most optical elements in the EUV collecting and imaging train have a high reflection coefficient for IR radiation, undesirable heating phenomena at the resist level are likely to occur. In this study a completely new principle is employed to obtain full separation of EUV and IR radiation from the source by a single optical component. While the application of a transmission filter would come at the expense of EUV throughput, this technique potentially enables wavelength separation without loosing reflectance compared to a conventional Mo/Si multilayer coated element. As a result this method provides full spectral purity from the source without loss in EUV throughput. Detailed calculations on the principal of functioning are presented.

The EUV Helium Spectrum in the Quiet Sun: A By-Product of Coronal Emission?

NASA Technical Reports Server (NTRS)

Andretta, Vincenzo; DelZanna, Giulio; Jordan, Stuart D.; Oegerle, William (Technical Monitor)

2002-01-01

In this paper we test one of the mechanisms proposed to explain the intensities and other observed properties of the solar helium spectrum, and in particular of its Extreme-Ultraviolet (EUV) resonance lines. The so-called Photoionisation-Recombination (P-R) mechanism involves photoionisation of helium atoms and ions by EUV coronal radiation, followed by recombination cascades. We present calibrated measurements of EUV flux obtained with the two CDS spectrometers on board SOHO, in quiescent solar regions. We were able to obtain an essentially complete estimate of the total photoionizing flux in the wavelength range below 504 A (the photoionisation threshold for He(I)), as well as simultaneous measurements with the same instruments of the intensities of the strongest EUV helium lines: He(II) lambda304, He(I) lambda584, and He(I) lambda537. We find that there are not enough EUV photons to account for the observed helium line intensities. More specifically, we conclude that He(II) intensities cannot be explained by the P-R mechanism. Our results, however, leave open the possibility that the He(I) spectrum could be formed by the P-R mechanism, with the He(II) lambda304 line as a significant photoionizating source.

Compact and Light-Weight Solar Spaceflight Instrument Designs Utilizing Newly Developed Miniature Free-Standing Zone Plates: EUV Radiometer and Limb-Scanning Monochromator

NASA Astrophysics Data System (ADS)

Seely, J. F.; McMullin, D. R.; Bremer, J.; Chang, C.; Sakdinawat, A.; Jones, A. R.; Vest, R.

2014-12-01

Two solar instrument designs are presented that utilize newly developed miniature free-standing zone plates having interconnected Au opaque bars and no support membrane resulting in excellent long-term stability in space. Both instruments are based on a zone plate having 4 mm outer diameter and 1 to 2 degree field of view. The zone plate collects EUV radiation and focuses a narrow bandpass through a pinhole aperture and onto a silicon photodiode detector. As a miniature radiometer, EUV irradiance is accurately determined from the zone plate efficiency and the photodiode responsivity that are calibrated at the NIST SURF synchrotron facility. The EUV radiometer is pointed to the Sun and measures the absolute solar EUV irradiance in high time cadence suitable for solar physics and space weather applications. As a limb-scanning instrument in low earth orbit, a miniature zone-plate monochromator measures the extinction of solar EUV radiation by scattering through the upper atmosphere which is a measure of the variability of the ionosphere. Both instruments are compact and light-weight and are attractive for CubeSats and other missions where resources are extremely limited.

ON THE ABSENCE OF EUV EMISSION FROM COMET C/2012 S1 (ISON)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryans, Paul; Pesnell, W. Dean

2016-05-10

When the sungrazing comet C/2012 S1 (ISON) made its perihelion passage within two solar radii of the Sun’s surface, it was expected to be a bright emitter at extreme ultraviolet (EUV) wavelengths. However, despite solar EUV telescopes repointing to track the orbit of the comet, no emission was detected. This “null result” is interesting in its own right, offering the possibility of placing limits on the size and composition of the nucleus. We explain the lack of detection by considering the properties of the comet and the solar atmosphere that determine the intensity of EUV emission from sungrazing comets. Bymore » comparing these properties with those of sungrazing comet C/2011 W3 (Lovejoy), which did emit in the EUV, we conclude that the primary factor resulting in non-detectable EUV emission from C/2012 S1 (ISON) was an insufficiently large nucleus. We conclude that the radius of C/2012 S1 (ISON) was at least a factor of four less than that of C/2011 W3 (Lovejoy). This is consistent with white-light observations in the days before perihelion that suggested the comet was dramatically reducing in size on approach.« less

Improvements in resist performance towards EUV HVM

NASA Astrophysics Data System (ADS)

Yildirim, Oktay; Buitrago, Elizabeth; Hoefnagels, Rik; Meeuwissen, Marieke; Wuister, Sander; Rispens, Gijsbert; van Oosten, Anton; Derks, Paul; Finders, Jo; Vockenhuber, Michaela; Ekinci, Yasin

2017-03-01

Extreme ultraviolet (EUV) lithography with 13.5 nm wavelength is the main option for sub-10nm patterning in the semiconductor industry. We report improvements in resist performance towards EUV high volume manufacturing. A local CD uniformity (LCDU) model is introduced and validated with experimental contact hole (CH) data. Resist performance is analyzed in terms of ultimate printing resolution (R), line width roughness (LWR), sensitivity (S), exposure latitude (EL) and depth of focus (DOF). Resist performance of dense lines at 13 nm half-pitch and beyond is shown by chemical amplified resist (CAR) and non-CAR (Inpria YA Series) on NXE scanner. Resolution down to 10nm half pitch (hp) is shown by Inpria YA Series resist exposed on interference lithography at the Paul Sherrer Institute. Contact holes contrast and consequent LCDU improvement is achieved on a NXE:3400 scanner by decreasing the pupil fill ratio. State-of-the-art imaging meets 5nm node requirements for CHs. A dynamic gas lock (DGL) membrane is introduced between projection optics box (POB) and wafer stage. The DGL membrane will suppress the negative impact of resist outgassing on the projection optics by 100%, enabling a wider range of resist materials to be used. The validated LCDU model indicates that the imaging requirements of the 3nm node can be met with single exposure using a high-NA EUV scanner. The current status, trends, and potential roadblocks for EUV resists are discussed. Our results mark the progress and the improvement points in EUV resist materials to support EUV ecosystem.

Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

NASA Technical Reports Server (NTRS)

Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B.; Allen, Maxwell J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C., Jr.

1991-01-01

The Multispectral Solar Telescope Array is a rocket-borne observatory which encompasses seven compact soft X-ray/EUV, multilayer-coated, and two compact far-UV, interference film-coated, Cassegrain and Ritchey-Chretien telescopes. Extensive measurements are presented on the efficiency and spectral bandpass of the X-ray/EUV telescopes. Attention is given to systematic errors and measurement errors.

EUV spectroscopy in astrophysics: The role of compact objects

NASA Astrophysics Data System (ADS)

Wood, K. S.; Kowalski, M. P.; Cruddace, R. G.; Barstow, M. A.

2006-01-01

The bulk of radiation from million-degree plasmas is emitted at EUV wavelengths. Such plasmas are ubiquitous in astrophysics, and examples include the atmospheres of white dwarfs, accretion phenomena in cataclysmic variables (CVs) and some active galactic nuclei (AGN), the coronae of active stars, and the interstellar medium (ISM) of our own galaxy as well as of others. Internally, white dwarfs are formally analogous to neutron stars, being stellar configurations where the thermal contribution to support is secondary. Both stellar types have various intrinsic and environmental parameters. Comparison of such analogous systems using scaled parameters can be fruitful. Source class characterization is mature enough that such analogies can be used to compare theoretical ideas across a wide dynamic range in parameters, one example being theories of quasiperiodic oscillations. However, the white dwarf side of this program is limited by the available photometry and spectroscopy at EUV wavelengths, where there exist critical spectral features that contain diagnostic information often not available at other wavelengths. Moreover, interstellar absorption makes EUV observations challenging. Results from an observation of the hot white dwarf G191-B2B are presented to demonstrate the promise of high-resolution EUV spectroscopy. Two types of CVs, exemplified by AM Her and EX Hya, are used to illustrate blending of spectroscopy and timing measurements. Dynamical timescales and envisioned performance parameters of next-generation EUV satellites (effective area >20 cm 2, spectral resolution >10,000) make possible a new level of source modeling. The importance of the EUV cannot be overlooked given that observations are continually being pushed to cosmological distances, where the spectral energy distributions of X-ray bright AGNs, for example, will have their maxima redshifted into the EUV. Sometimes wrongly dismissed for limitations of small bandwidth or local view from optical depth limitations, the EUV is instead a gold mine of information bearing upon key issues in compact objects, but it is information that must be won through the triple combination of high-spectral resolution, large area, and application of advanced theory.

Mars Thermospheric Temperature Sensitivity to Solar EUV Forcing from the MAVEN EUV Monitor

NASA Astrophysics Data System (ADS)

Thiemann, Ed; Eparvier, Francis; Andersson, Laila; Pilinski, Marcin; Chamberlin, Phillip; Fowler, Christopher; MAVEN Extreme Ultraviolet Monitor Team, MAVEN Langmuir Probe and Waves Team

2017-10-01

Solar extreme ultraviolet (EUV) radiation is the primary heat source for the Mars thermosphere, and the primary source of long-term temperature variability. The Mars obliquity, dust cycle, tides and waves also drive thermospheric temperature variability; and it is important to quantify the role of each in order to understand processes in the upper atmosphere today and, ultimately, the evolution of Mars climate over time. Although EUV radiation is the dominant heating mechanism, accurately measuring the thermospheric temperature sensitivity to EUV forcing has remained elusive, in part, because Mars thermospheric temperature varies dramatically with latitude and local time (LT), ranging from 150K on the nightside to 300K on the dayside. It follows that studies of thermospheric variability must control for location.Instruments onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiter have begun to characterize thermospheric temperature sensitivity to EUV forcing. Bougher et al. [2017] used measurements from the Imaging Ultraviolet Spectrograph (IUVS) and the Neutral Gas and Ion Mass Spectrometer (NGIMS) to characterize solar activity trends in the thermosphere with some success. However, aside from restricting measurements to solar zenith angles (SZAs) below 75 degrees, they were unable to control for latitude and LT because repeat-track observations from either instrument were limited or unavailable.The MAVEN EUV Monitor (EUVM) has recently demonstrated the capability to measure thermospheric density from 100 to 200 km with solar occultations of its 17-22 nm channel. These new density measurements are ideal for tracking the long-term thermospheric temperature variability because they are inherently constrained to either 06:00 or 18:00 LT, and the orbit has precessed to include a range of ecliptic latitudes, a number of which have been revisited multiple times over 2.5 years. In this study we present, for the first-time, measurements of thermospheric temperature sensitivity to EUV forcing derived from the EUVM measurements. These results include sensitives measured at the poles and near the equator for both terminators; therefore, we will also discuss the role of latitude on EUV temperature sensitivity.

Time-Resolved Spectroscopy of Active Binary Stars

NASA Technical Reports Server (NTRS)

Brown, Alexander

2000-01-01

This NASA grant covered EUVE observing and data analysis programs during EUVE Cycle 5 GO observing. The research involved a single Guest Observer project 97-EUVE-061 "Time-Resolved Spectroscopy of Active Binary Stars". The grant provided funding that covered 1.25 months of the PI's salary. The activities undertaken included observation planning and data analysis (both temporal and spectral). This project was awarded 910 ksec of observing time to study seven active binary stars, all but one of which were actually observed. Lambda-And was observed on 1997 Jul 30 - Aug 3 and Aug 7-14 for a total of 297 ksec; these observations showed two large complex flares that were analyzed by Osten & Brown (1999). AR Psc, observed for 350 ksec on 1997 Aug 27 - Sep 13, showed only relatively small flares that were also discussed by Osten & Brown (1999). EUVE observations of El Eri were obtained on 1994 August 24-28, simultaneous with ASCA X-ray spectra. Four flares were detected by EUVE with one of these also observed simultaneously, by ASCA. The other three EUVE observations were of the stars BY Dra (1997 Sep 22-28), V478 Lyr (1998 May 18-27), and sigma Gem (1998 Dec 10-22). The first two stars showed a few small flares. The sigma Gem data shows a beautiful complete flare with a factor of ten peak brightness compared to quiescence. The flare rise and almost all the decay phase are observed. Unfortunately no observations in other spectral regions were obtained for these stars. Analysis of the lambda-And and AR Psc observations is complete and the results were published in Osten & Brown (1999). Analysis of the BY Dra, V478 Lyr and sigma Gem EUVE data is complete and will be published in Osten (2000, in prep.). The El Eri EUV analysis is also completed and the simultaneous EUV/X-ray study will be published in Osten et al. (2000, in prep.). Both these latter papers will be submitted in summer 2000. All these results will form part of Rachel Osten's PhD thesis.

Exploring dynamic events in the solar corona

NASA Astrophysics Data System (ADS)

Downs, Cooper James

With the advent of modern computational technology it is now becoming the norm to employ detailed 3D computer models as empirical tools that directly account for the inhomogeneous nature of the Sun-Heliosphere environment. The key advantage of this approach lies in the ability to compare model results directly to observational data and to use a successful comparison (or lack thereof) to glean information on the underlying physical processes. Using extreme ultraviolet waves (EUV waves) as the overarching scientific driver, we apply this observation modeling approach to study the complex dynamics of the magnetic and thermodynamic structures that are observed in the low solar corona. Representing a highly non-trivial effort, this work includes three main scientific thrusts: an initial modeling effort and two EUV wave case-studies. First we document the development of the new Low Corona (LC) model, a 3D time-dependent thermodynamic magnetohydrodynamic (MHD) model implemented within the Space Weather Modeling Framework (SWMF). Observation synthesis methods are integrated within the LC model, which provides the ability to compare model results directly to EUV imaging observations taken by spacecraft. The new model is then used to explore the dynamic interplay between magnetic structures and thermodynamic energy balance in the corona that is caused by coronal heating mechanisms. With the model development complete, we investigate the nature of EUV waves in detail through two case-studies. Starting with the 2008 March 25 event, we conduct a series of numerical simulations that independently vary fundamental parameters thought to govern the physical mechanisms behind EUV waves. Through the subsequent analysis of the 3D data and comparison to observations we find evidence for both wave and non-wave mechanisms contributing to the EUV wave signal. We conclude with a comprehensive observation and modeling analysis of the 2010 June 13 EUV wave event, which was observed by the recently launched Solar Dynamics Observatory. We use a high resolution simulation of the transient to unambiguously characterize the globally propagating front of EUV wave as a fast-mode magnetosonic wave, and use the rich set of observations to place the many other facets of the EUV transient within a unified scenario involving wave and non-wave components.

Increasing EUV source efficiency via recycling of radiation power

NASA Astrophysics Data System (ADS)

Hassanein, Ahmed; Sizyuk, Valeryi; Sizyuk, Tatyana; Johnson, Kenneth C.

2018-03-01

EUV source power is critical for advanced lithography, for achieving economical throughput performance and also for minimizing stochastic patterning effects. Power conversion efficiency can be increased by recycling plasma-scattered laser radiation and other out-of-band radiation back to the plasma via retroreflective optics. Radiation both within and outside of the collector light path can potentially be recycled. For recycling within the collector path, the system uses a diffractive collection mirror that concomitantly filters all laser and out-of-band radiation out of the EUV output. In this paper we review the optical design concept for power recycling and present preliminary plasma-physics simulation results showing a potential gain of 60% in EUV conversion efficiency.

Application of Laser Plasma Sources of Soft X-rays and Extreme Ultraviolet (EUV) in Imaging, Processing Materials and Photoionization Studies

NASA Astrophysics Data System (ADS)

Fiedorowicz, H.; Bartnik, A.; Wachulak, P. W.; Jarocki, R.; Kostecki, J.; Szczurek, M.; Ahad, I. U.; Fok, T.; Szczurek, A.; Wȩgrzyński, Ł.

In the paper we present new applications of laser plasma sources of soft X-rays and extreme ultraviolet (EUV) in various areas of plasma physics, nanotechnology and biomedical engineering. The sources are based on a gas puff target irradiated with nanosecond laser pulses from commercial Nd: YAG lasers, generating pulses with time duration from 1 to 10 ns and energies from 0.5 to 10 J at a 10 Hz repetition rate. The targets are produced with the use of a double valve system equipped with a special nozzle to form a double-stream gas puff target which allows for high conversion efficiency of laser energy into soft X-rays and EUV without degradation of the nozzle. The sources are equipped with various optical systems to collect soft X-ray and EUV radiation and form the radiation beam. New applications of these sources in imaging, including EUV tomography and soft X-ray microscopy, processing of materials and photoionization studies are presented.

Nanoimaging using soft X-ray and EUV laser-plasma sources

NASA Astrophysics Data System (ADS)

Wachulak, Przemyslaw; Torrisi, Alfio; Ayele, Mesfin; Bartnik, Andrzej; Czwartos, Joanna; Węgrzyński, Łukasz; Fok, Tomasz; Fiedorowicz, Henryk

2018-01-01

In this work we present three experimental, compact desk-top imaging systems: SXR and EUV full field microscopes and the SXR contact microscope. The systems are based on laser-plasma EUV and SXR sources based on a double stream gas puff target. The EUV and SXR full field microscopes, operating at 13.8 nm and 2.88 nm wavelengths are capable of imaging nanostructures with a sub-50 nm spatial resolution and short (seconds) exposure times. The SXR contact microscope operates in the "water-window" spectral range and produces an imprint of the internal structure of the imaged sample in a thin layer of SXR sensitive photoresist. Applications of such desk-top EUV and SXR microscopes, mostly for biological samples (CT26 fibroblast cells and Keratinocytes) are also presented. Details about the sources, the microscopes as well as the imaging results for various objects will be presented and discussed. The development of such compact imaging systems may be important to the new research related to biological, material science and nanotechnology applications.

EB and EUV lithography using inedible cellulose-based biomass resist material

NASA Astrophysics Data System (ADS)

Takei, Satoshi; Hanabata, Makoto; Oshima, Akihiro; Kashiwakura, Miki; Kozawa, Takahiro; Tagawa, Seiichi

2016-03-01

The validity of our approach of inedible cellulose-based resist material derived from woody biomass has been confirmed experimentally for the use of pure water in organic solvent-free water spin-coating and tetramethylammonium hydroxide(TMAH)-free water-developable techniques of eco-conscious electron beam (EB) and extreme-ultraviolet (EUV) lithography. The water developable, non-chemically amplified, high sensitive, and negative tone resist material in EB and EUV lithography was developed for environmental affair, safety, easiness of handling, and health of the working people. The inedible cellulose-based biomass resist material was developed by replacing the hydroxyl groups in the beta-linked disaccharides with EB and EUV sensitive groups. The 50-100 nm line and space width, and little footing profiles of cellulose-based biomass resist material on hardmask and layer were resolved at the doses of 10-30 μC/cm2. The eco-conscious lithography techniques was referred to as green EB and EUV lithography using inedible cellulose-based biomass resist material.

High performance EUV multilayer structures insensitive to capping layer optical parameters.

PubMed

Pelizzo, Maria Guglielmina; Suman, Michele; Monaco, Gianni; Nicolosi, Piergiorgio; Windt, David L

2008-09-15

We have designed and tested a-periodic multilayer structures containing protective capping layers in order to obtain improved stability with respect to any possible changes of the capping layer optical properties (due to oxidation and contamination, for example)-while simultaneously maximizing the EUV reflection efficiency for specific applications, and in particular for EUV lithography. Such coatings may be particularly useful in EUV lithographic apparatus, because they provide both high integrated photon flux and higher stability to the harsh operating environment, which can affect seriously the performance of the multilayer-coated projector system optics. In this work, an evolutive algorithm has been developed in order to design these a-periodic structures, which have been proven to have also the property of stable performance with respect to random layer thickness errors that might occur during coating deposition. Prototypes have been fabricated, and tested with EUV and X-ray reflectometry, and secondary electron spectroscopy. The experimental results clearly show improved performance of our new a-periodic coatings design compared with standard periodic multilayer structures.

Direct EUV/X-Ray Modulation of the Ionosphere During the August 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Mrak, Sebastijan; Semeter, Joshua; Drob, Douglas; Huba, J. D.

2018-05-01

The great American total solar eclipse of 21 August 2017 offered a fortuitous opportunity to study the response of the atmosphere and ionosphere using a myriad of ground instruments. We have used the network of U.S. Global Positioning System receivers to examine perturbations in maps of ionospheric total electron content (TEC). Coherent large-scale variations in TEC have been interpreted by others as gravity wave-induced traveling ionospheric disturbances. However, the solar disk had two active regions at that time, one near the center of the disk and one at the edge, which resulted in an irregular illumination pattern in the extreme ultraviolet (EUV)/X-ray bands. Using detailed EUV occultation maps calculated from the National Aeronautics and Space Administration Solar Dynamics Observatory Atmospheric Imaging Assembly images, we show excellent agreement between TEC perturbations and computed gradients in EUV illumination. The results strongly suggest that prominent large-scale TEC disturbances were consequences of direct EUV modulation, rather than gravity wave-induced traveling ionospheric disturbances.

Normal incidence spectrophotometer using high density transmission grating technology and highly efficiency silicon photodiodes for absolute solar EUV irradiance measurements

NASA Technical Reports Server (NTRS)

Ogawa, H. S.; Mcmullin, D.; Judge, D. L.; Korde, R.

1992-01-01

New developments in transmission grating and photodiode technology now make it possible to realize spectrometers in the extreme ultraviolet (EUV) spectral region (wavelengths less than 1000 A) which are expected to be virtually constant in their diffraction and detector properties. Time dependent effects associated with reflection gratings are eliminated through the use of free standing transmission gratings. These gratings together with recently developed and highly stable EUV photodiodes have been utilized to construct a highly stable normal incidence spectrophotometer to monitor the variability and absolute intensity of the solar 304 A line. Owing to its low weight and compactness, such a spectrometer will be a valuable tool for providing absolute solar irradiance throughout the EUV. This novel instrument will also be useful for cross-calibrating other EUV flight instruments and will be flown on a series of Hitchhiker Shuttle Flights and on SOHO. A preliminary version of this instrument has been fabricated and characterized, and the results are described.

Mo/Si and Mo/Be multilayer thin films on Zerodur substrates for extreme-ultraviolet lithography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mirkarimi, Paul B.; Bajt, Sasa; Wall, Mark A.

2000-04-01

Multilayer-coated Zerodur optics are expected to play a pivotal role in an extreme-ultraviolet (EUV) lithography tool. Zerodur is a multiphase, multicomponent material that is a much more complicated substrate than commonly used single-crystal Si or fused-silica substrates. We investigate the effect of Zerodur substrates on the performance of high-EUV reflectance Mo/Si and Mo/Be multilayer thin films. For Mo/Si the EUV reflectance had a nearly linear dependence on substrate roughness for roughness values of 0.06-0.36 nm rms, and the FWHM of the reflectance curves (spectral bandwidth) was essentially constant over this range. For Mo/Be the EUV reflectance was observed to decreasemore » more steeply than Mo/Si for roughness values greater than approximately 0.2-0.3 nm. Little difference was observed in the EUV reflectivity of multilayer thin films deposited on different substrates as long as the substrate roughness values were similar. (c) 2000 Optical Society of America.« less

Mo/Si and Mo/Be multilayer thin films on Zerodur substrates for extreme-ultraviolet lithography.

PubMed

Mirkarimi, P B; Bajt, S; Wall, M A

2000-04-01

Multilayer-coated Zerodur optics are expected to play a pivotal role in an extreme-ultraviolet (EUV) lithography tool. Zerodur is a multiphase, multicomponent material that is a much more complicated substrate than commonly used single-crystal Si or fused-silica substrates. We investigate the effect of Zerodur substrates on the performance of high-EUV reflectance Mo/Si and Mo/Be multilayer thin films. For Mo/Si the EUV reflectance had a nearly linear dependence on substrate roughness for roughness values of 0.06-0.36 nm rms, and the FWHM of the reflectance curves (spectral bandwidth) was essentially constant over this range. For Mo/Be the EUV reflectance was observed to decrease more steeply than Mo/Si for roughness values greater than approximately 0.2-0.3 nm. Little difference was observed in the EUV reflectivity of multilayer thin films deposited on different substrates as long as the substrate roughness values were similar.

The extreme ultraviolet explorer

NASA Technical Reports Server (NTRS)

Bowyer, Stuart; Malina, Roger F.

1990-01-01

The Extreme Ultraviolet Explorer (EUVE) mission, currently scheduled for launch in September 1991, is described. The primary purpose of the mission is to survey the celestial sphere for astronomical sources of Extreme Ultraviolet (EUV) radiation. The survey will be accomplished with the use of three EUV telescopes, each sensitive to a different segment of the EUV band. A fourth telescope will perform a high sensitivity search of a limited sample of the sky in the shortest wavelength bands. The all sky survey will be carried out in the first six months of the mission and will be made in four bands, or colors. The second phase of the mission, conducted entirely by guest observers selected by NASA, will be devoted to spectroscopic observations of EUV sources. The performance of the instrument components is described. An end to end model of the mission, from a stellar source to the resulting scientific data, was constructed. Hypothetical data from astronomical sources processed through this model are shown.

EUVE/XTE orbit decay study

NASA Technical Reports Server (NTRS)

Richon, K.; Hashmall, J.; Lambertson, M.; Phillips, T.

1988-01-01

The Explorer Platform (EP) program currently comprises two missions, the Extreme Ultraviolet Explorer (EUVE) and the X-ray Timing Explorer (XTE), each of which consists of a scientific payload mounted to the EP. The EP has no orbit maintenance capability. The EP with the EUVE payload will be launched first. At the end of the EUVE mission, the spacecraft will be serviced by the Space Transportation System (STS), and the EUVE instrument will be exchanged for the XTE. The XTE mission will continue until reentry or reservicing by the STS. Because the missions will be using the EP sequentially, the orbit requirements are unusually constrained by orbit decay rates. The initial altitude must be selected so that, by the end of the EUVE mission (2.5 years), the spacecraft will have decayed to an altitude within the STS capabilities. In addition, the payload exchange must occur at an altitude that ensures meeting the minimum XTE mission lifetime (3 years) because no STS reboost will be available. Studies were performed using the Goddard Mission Analysis System to estimate the effects of mass, cross-sectional area, and solar flux on the fulfillment of mission requirements. In addition to results from these studies, conclusions are presented as to the accuracy of the Marshall Space Flight Center solar flux predictions.

Reconstruction of Solar EUV Flux 1740-2015

NASA Astrophysics Data System (ADS)

Svalgaard, L.

2015-12-01

Solar Extreme Ultraviolet (EUV) radiation creates the conducting E-layer of the ionosphere, mainly by photo ionization of molecular Oxygen. Solar heating of the ionosphere creates thermal winds which by dynamo action induce an electric field driving an electric current having a magnetic effect observable on the ground, as was discovered by G. Graham in 1722. The current rises and sets with the Sun and thus causes a readily observable diurnal variation of the geomagnetic field, allowing us the deduce the conductivity and thus the EUV flux as far back as reliable magnetic data reach. High-quality data go back to the 'Magnetic Crusade' of the 1830s and less reliable, but still usable, data are available for portions of the hundred years before that. J.R. Wolf and, independently, J.-A. Gautier discovered the dependence of the diurnal variation on solar activity, and today we understand and can invert that relationship to construct a reliable record of the EUV flux from the geomagnetic record. We compare that to the F10.7 flux and the sunspot number, and find that the reconstructed EUV flux reproduces the F10.7 flux with great accuracy. On the other hand, it appears that the Relative Sunspot Number as currently defined is beginning to no longer be a faithful representation of solar magnetic activity, at least as measured by the EUV and related indices. The reconstruction suggests that the EUV flux reaches the same low (but non-zero) value at every sunspot minimum (possibly including Grand Minima), representing an invariant 'solar magnetic ground state'.

Modeling of radiative properties of Sn plasmas for extreme-ultraviolet source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasaki, Akira; Sunahara, Atsushi; Furukawa, Hiroyuki

Atomic processes in Sn plasmas are investigated for application to extreme-ultraviolet (EUV) light sources used in microlithography. We develop a full collisional radiative (CR) model of Sn plasmas based on calculated atomic data using Hebrew University Lawrence Livermore Atomic Code (HULLAC). Resonance and satellite lines from singly and multiply excited states of Sn ions, which contribute significantly to the EUV emission, are identified and included in the model through a systematic investigation of their effect on the emission spectra. The wavelengths of the 4d-4f+4p-4d transitions of Sn{sup 5+} to Sn{sup 13+} are investigated, because of their importance for determining themore » conversion efficiency of the EUV source, in conjunction with the effect of configuration interaction in the calculation of atomic structure. Calculated emission spectra are compared with those of charge exchange spectroscopy and of laser produced plasma EUV sources. The comparison is also carried out for the opacity of a radiatively heated Sn sample. A reasonable agreement is obtained between calculated and experimental EUV emission spectra observed under the typical condition of EUV sources with the ion density and ionization temperature of the plasma around 10{sup 18} cm{sup -3} and 20 eV, respectively, by applying a wavelength correction to the resonance and satellite lines. Finally, the spectral emissivity and opacity of Sn plasmas are calculated as a function of electron temperature and ion density. The results are useful for radiation hydrodynamics simulations for the optimization of EUV sources.« less

The extreme ultraviolet spectra of low-redshift radio-loud quasars

NASA Astrophysics Data System (ADS)

Punsly, Brian; Reynolds, Cormac; Marziani, Paola; O'Dea, Christopher P.

2016-07-01

This paper reports on the extreme ultraviolet (EUV) spectrum of three low-redshift (z ˜ 0.6) radio-loud quasars, 3C 95, 3C 57 and PKS 0405-123. The spectra were obtained with the Cosmic Origins Spectrograph of the Hubble Space Telescope. The bolometric thermal emission, Lbol, associated with the accretion flow is a large fraction of the Eddington limit for all of these sources. We estimate the long-term time-averaged jet power, overline{Q}, for the three sources. overline{Q}/L_{bol}, is shown to lie along the correlation of overline{Q}/L_{bol}, and αEUV found in previous studies of the EUV continuum of intermediate and high-redshift quasars, where the EUV continuum flux density between 1100 and 700 Å is defined by F_{ν } ˜ ν ^{-α _{EUV}}. The high Eddington ratios of the three quasars extend the analysis into a wider parameter space. Selecting quasars with high Eddington ratios has accentuated the statistical significance of the partial correlation analysis of the data. Namely, the correlation of overline{Q}/L_{bol} and αEUV is fundamental, and the correlation of overline{Q} and αEUV is spurious at a very high statistical significance level (99.8 per cent). This supports the regulating role of ram pressure of the accretion flow in magnetically arrested accretion models of jet production. In the process of this study, we use multifrequency and multiresolution Very Large Array radio observations to determine that one of the bipolar jets in 3C 57 is likely frustrated by galactic gas that keeps the jet from propagating outside the host galaxy.

It's Time For A New EUV Mission

NASA Astrophysics Data System (ADS)

Kowalski, Michael Paul; Wood, K. S.; Barstow, M. A.; Cruddace, R. G.

2010-01-01

The J-PEX high-resolution EUV spectrometer has made a breakthrough in capability with an effective area of 7 cm2 (220-245 Å) and resolving power of 4000, which exceed EUVE by factors of 7 and 20 respectively, and cover a range beyond the 170-Å cutoff of the Chandra LETG. The EUV includes critical spectral features containing diagnostic information often not available at other wavelengths (e.g., He II Ly series), and the bulk of radiation from million degree plasmas is emitted in the EUV. Such plasmas are ubiquitous, and examples include the atmospheres of white dwarfs; accretion phenomena in young stars, CVs and AGN; stellar coronae; and the ISM of our own galaxy and of others. However, sensitive EUV spectroscopy of high resolving power is required to resolve source spectral lines and edges unambiguously, to identify features produced by the intervening ISM, and to measure line profiles and Doppler shifts. This allows exploitation of the full range of plasma diagnostic techniques developed in laboratory and solar physics. J-PEX has flown twice on NASA sounding rockets. In 2001 we observed the isolated white dwarf G191-B2B and detected both ISM and photospheric lines. In 2008 we successfully observed the binary white dwarf Feige 24, but observation time is severely limited with sounding rockets. NASA has approved no new EUV mission, but it is time for one. Here we describe the scientific case for high-resolution EUV spectroscopy, summarize the technology that makes such measurements practical, and present a concept for a 3-month orbital mission, in which J-PEX is modified for a low-cost orbital mission to acquire sensitive high-resolution spectra for 30 white dwarfs, making an important contribution to the study of white dwarf evolution and hence the chemical balance of the Galaxy, and to the understanding of structure in the LISM.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Pei-Yang; Zhang, Guojing; Gullickson, Eric M.

Extreme ultraviolet lithography (EUVL) mask multi-layer (ML) blank surface roughness specification historically comes from blank defect inspection tool requirement. Later, new concerns on ML surface roughness induced wafer pattern line width roughness (LWR) arise. In this paper, we have studied wafer level pattern LWR as a function of EUVL mask surface roughness via High-NA Actinic Reticle Review Tool. We found that the blank surface roughness induced LWR at current blank roughness level is in the order of 0.5nm 3σ for NA=0.42 at the best focus. At defocus of ±40nm, the corresponding LWR will be 0.2nm higher. Further reducing EUVL maskmore » blank surface roughness will increase the blank cost with limited benefit in improving the pattern LWR, provided that the intrinsic resist LWR is in the order of 1nm and above.« less

EUV and X-ray spectroheliograph study

NASA Technical Reports Server (NTRS)

Knox, E. D.; Pastor, R. A.; Salamon, A. L.; Sterk, A. A.

1975-01-01

The results of a program directed toward the definition of an EUV and X-ray spectroheliograph which has significant performance and operational improvements over the OSO-7 instrument are documented. The program investigated methods of implementing selected changes and incorporated the results of the study into a set of drawings which defines the new instrument. The EUV detector performance degradation observed during the OSO-7 mission was investigated and the most probable cause of the degradation identified.

Principal investigators data package for Project Initiation Conference (PIC): EUVS sounding rocket no. 36.117CL. Target: Venus

NASA Technical Reports Server (NTRS)

Stern, S. Alan

1993-01-01

The region of the UV between 500 and 1200 A is a rich one for the study of planetary and astrophysical targets. EUV atmospheric spectroscopy opens up an important window on ion and neutral nitrogen, oxygen, and noble gas emissions. In this document we describe the specific scientific background and motivations for this Venus EUV rocket observation along with experiment design and mission parameters.

A sensitive EUV Schwarzschild microscope for plasma studies with sub-micrometer resolution

DOE PAGES

Zastrau, U.; Rodel, C.; Nakatsutsumi, M.; ...

2018-02-05

We present an extreme ultraviolet (EUV) microscope using a Schwarzschild objective which is optimized for single-shot sub-micrometer imaging of laser-plasma targets. The microscope has been designed and constructed for imaging the scattering from an EUV-heated solid-density hydrogen jet. Here, imaging of a cryogenic hydrogen target was demonstrated using single pulses of the free-electron laser in Hamburg (FLASH) free-electron laser at a wavelength of 13.5 nm. In a single exposure, we observe a hydrogen jet with ice fragments with a spatial resolution in the sub-micrometer range. In situ EUV imaging is expected to enable novel experimental capabilities for warm dense mattermore » studies of micrometer-sized samples in laser-plasma experiments.« less

A sensitive EUV Schwarzschild microscope for plasma studies with sub-micrometer resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zastrau, U.; Rodel, C.; Nakatsutsumi, M.

We present an extreme ultraviolet (EUV) microscope using a Schwarzschild objective which is optimized for single-shot sub-micrometer imaging of laser-plasma targets. The microscope has been designed and constructed for imaging the scattering from an EUV-heated solid-density hydrogen jet. Here, imaging of a cryogenic hydrogen target was demonstrated using single pulses of the free-electron laser in Hamburg (FLASH) free-electron laser at a wavelength of 13.5 nm. In a single exposure, we observe a hydrogen jet with ice fragments with a spatial resolution in the sub-micrometer range. In situ EUV imaging is expected to enable novel experimental capabilities for warm dense mattermore » studies of micrometer-sized samples in laser-plasma experiments.« less

Coater/developer based techniques to improve high-resolution EUV patterning defectivity

NASA Astrophysics Data System (ADS)

Hontake, Koichi; Huli, Lior; Lemley, Corey; Hetzer, Dave; Liu, Eric; Ko, Akiteru; Kawakami, Shinichiro; Shimoaoki, Takeshi; Hashimoto, Yusaku; Tanaka, Koichiro; Petrillo, Karen; Meli, Luciana; De Silva, Anuja; Xu, Yongan; Felix, Nelson; Johnson, Richard; Murray, Cody; Hubbard, Alex

2017-10-01

Extreme ultraviolet lithography (EUVL) technology is one of the leading candidates under consideration for enabling the next generation of devices, for 7nm node and beyond. As the focus shifts to driving down the 'effective' k1 factor and enabling the full scaling entitlement of EUV patterning, new techniques and methods must be developed to reduce the overall defectivity, mitigate pattern collapse, and eliminate film-related defects. In addition, CD uniformity and LWR/LER must be improved in terms of patterning performance. Tokyo Electron Limited (TEL™) and IBM Corporation are continuously developing manufacturing quality processes for EUV. In this paper, we review the ongoing progress in coater/developer based processes (coating, developing, baking) that are required to enable EUV patterning.

Thin film filter lifetesting results in the extreme ultraviolet

NASA Technical Reports Server (NTRS)

Vedder, P. W.; Vallerga, J. V.; Gibson, J. L.; Stock, J.; Siegmund, O. H. W.

1993-01-01

We present the results of the thin film filter lifetesting program conducted as part of the NASA Extreme Ultraviolet Explorer (EUVE) satellite mission. This lifetesting program is designed to monitor changes in the transmission and mechanical properties of the EUVE filters over the lifetime of the mission (fabrication, assembly, launch and operation). Witness test filters were fabricated from thin film foils identical to those used in the flight filters. The witness filters have been examined and calibrated periodically over the past seven years. The filters have been examined for evidence of pinholing, mechanical degradation, and oxidation. Absolute transmissions of the flight and witness filters have been measured in the extreme ultraviolet (EUV) over six orders of magnitude at numerous wavelengths using the Berkeley EUV Calibration Facility.

Solar EUV irradiance from the San Marco ASSI - A reference spectrum

NASA Technical Reports Server (NTRS)

Schmidtke, Gerhard; Woods, Thomas N.; Worden, John; Rottman, Gary J.; Doll, Harry; Wita, Claus; Solomon, Stanley C.

1992-01-01

The only satellite measurement of the solar EUV irradiance during solar cycle 22 has been obtained with the Airglow Solar Spectrometer Instrument (ASSI) aboard the San Marco 5 satellite flown in 1988. The ASSI in-flight calibration parameters are established by using the internal capabilities of ASSI and by comparing ASSI results to the results from other space-based experiments on the ASSI calibration rocket and the Solar Mesospheric Explorer (SME). A solar EUV irradiance spectrum derived from ASSI observations on November 10, 1988 is presented as a reference spectrum for moderate solar activity for the aeronomy community. This ASSI spectrum should be considered as a refinement and extension of the solar EUV spectrum published for the same day by Woods and Rottman (1990).

Integration of mask and silicon metrology in DFM

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Sugiyama, Akiyuki; Toyoda, Yasutaka

2009-03-01

We have developed a highly integrated method of mask and silicon metrology. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. We have inspected the high accuracy, stability and reproducibility in the experiments of integration. The accuracy is comparable with that of the mask and silicon CD-SEM metrology. In this report, we introduce the experimental results and the application. As shrinkage of design rule for semiconductor device advances, OPC (Optical Proximity Correction) goes aggressively dense in RET (Resolution Enhancement Technology). However, from the view point of DFM (Design for Manufacturability), the cost of data process for advanced MDP (Mask Data Preparation) and mask producing is a problem. Such trade-off between RET and mask producing is a big issue in semiconductor market especially in mask business. Seeing silicon device production process, information sharing is not completely organized between design section and production section. Design data created with OPC and MDP should be linked to process control on production. But design data and process control data are optimized independently. Thus, we provided a solution of DFM: advanced integration of mask metrology and silicon metrology. The system we propose here is composed of followings. 1) Design based recipe creation: Specify patterns on the design data for metrology. This step is fully automated since they are interfaced with hot spot coordinate information detected by various verification methods. 2) Design based image acquisition: Acquire the images of mask and silicon automatically by a recipe based on the pattern design of CD-SEM.It is a robust automated step because a wide range of design data is used for the image acquisition. 3) Contour profiling and GDS data generation: An image profiling process is applied to the acquired image based on the profiling method of the field proven CD metrology algorithm. The detected edges are then converted to GDSII format, which is a standard format for a design data, and utilized for various DFM systems such as simulation. Namely, by integrating pattern shapes of mask and silicon formed during a manufacturing process into GDSII format, it makes it possible to bridge highly accurate pattern profile information over to the design field of various EDA systems. These are fully integrated into design data and automated. Bi-directional cross probing between mask data and process control data is allowed by linking them. This method is a solution for total optimization that covers Design, MDP, mask production and silicon device producing. This method therefore is regarded as a strategic DFM approach in the semiconductor metrology.

High-precision MoSi multilayer coatings for radial and 2D designs on curved optics

NASA Astrophysics Data System (ADS)

Kriese, Michael D.; Li, Yang; Platonov, Yuriy Y.

2017-10-01

The development of industrial infrastructure for EUV lithography requires a wide array of optics beyond the mask and the scanner optics, which include optics for critical instruments such as exposure testing and actinic inspection. This paper will detail recent results in the production of a variety of high-precision multilayer coatings achieved to support this development. It is critical that the optical designs factor in the capabilities of the achievable multilayer gradients and the associated achievable precision, including impact to surface distortion from the added figure error of the multilayer coating, which adds additional requirements of a specific shape to the period distribution. For example, two different coatings may achieve a ±0.2% variation in multilayer period, but have considerably different added figure error. Part I of the paper will focus on radially-symmetric spherical and aspherical optics. Typical azimuthal uniformity (variation at a fixed radius) achieved is less than ±0.005nm total variation, including measurement precision, on concave optics up to 200mm diameter. For highly curved convex optics (radius of curvature less than 50mm), precision is more challenging and the total variation increases to ±0.01nm total variation for optics 10-30mm in diameter. Total added figure error achieved has been as low as 0.05nm. Part II of the paper will focus on multilayer designs graded in two directions, rather than radially, in order to accommodate the increased complexity of elliptical, toroidal and hyperbolic surfaces. In most cases, the symmetry of the required multilayer gradient does not match the symmetry of the optical surface, and this interaction must be countered via the process design. Achieving such results requires additional flexibility in the design of the deposition equipment, and will be discussed with several examples in the paper, such as the use of variable velocity of an inline substrate carrier in conjunction with a shaped target aperture to produce ±0.03nm total variation on an off-axis elliptical surface.

DFM for maskmaking: design-aware flexible mask-defect analysis

NASA Astrophysics Data System (ADS)

Driessen, Frank A. J. M.; Westra, J.; Scheffer, M.; Kawakami, K.; Tsujimoto, E.; Yamaji, M.; Kawashima, T.; Hayashi, N.

2007-10-01

We present a novel software system that combines design intent as known by EDA designers with defect inspection results from the maskshop to analyze the severity of defects on photomasks. The software -named Takumi Design- Driven Defect Analyzer (TK-D3A)- analyzes defects by combining actions in the image domain with actions in the design domain and outputs amongst others flexible mask-repair decisions in production formats used by the maskshop. Furthermore, TK-D3A outputs clips of layout (GDS/OASIS) that can be viewed with its graphical user interface for easy review of the defects and associated repair decisions. As inputs the system uses reticle defect-inspection data (text and images) and the respective multi-layer design layouts with the definitions of criticalities. The system does not require confidential design data from IDM, Fabless Design House, or Foundry to be sent to the maskshop and it also has minimal impact on the maskshop's mode of operation. The output of TK-D3A is designed to realize value to the maskshop and its customers in the forms of: 1) improved yield, 2) reduction of delivery times of masks to customers, and 3) enhanced utilization of the maskshop's installed tool base. The system was qualified together with a major IDM on a large set of production reticles in the 90 and beyond-65 nm technology nodes of which results will be presented that show the benefits for maskmaking. The accuracy in detecting defects is extremely high. We show the system's capability to analyze defects well below the pixel resolution of all inspection tools used, as well as the capability to extract multiple types of transmission defects. All of these defects are analyzed design-criticality-aware by TK-D3A, resulting in a large fraction of defects that do not need to be repaired because they are located in non-critical or less-critical parts of the layout, or, more importantly, turn out to be repairable or negligible despite of originally being classified as unrepairable when no such criticality knowledge is used. Finally, we show that the runtimes of TK-D3A are relatively short, despite the fact that the system operates on full-chip designs.

Integrated approach to improving local CD uniformity in EUV patterning

NASA Astrophysics Data System (ADS)

Liang, Andrew; Hermans, Jan; Tran, Timothy; Viatkina, Katja; Liang, Chen-Wei; Ward, Brandon; Chuang, Steven; Yu, Jengyi; Harm, Greg; Vandereyken, Jelle; Rio, David; Kubis, Michael; Tan, Samantha; Dusa, Mircea; Singhal, Akhil; van Schravendijk, Bart; Dixit, Girish; Shamma, Nader

2017-03-01

Extreme ultraviolet (EUV) lithography is crucial to enabling technology scaling in pitch and critical dimension (CD). Currently, one of the key challenges of introducing EUV lithography to high volume manufacturing (HVM) is throughput, which requires high source power and high sensitivity chemically amplified photoresists. Important limiters of high sensitivity chemically amplified resists (CAR) are the effects of photon shot noise and resist blur on the number of photons received and of photoacids generated per feature, especially at the pitches required for 7 nm and 5 nm advanced technology nodes. These stochastic effects are reflected in via structures as hole-to-hole CD variation or local CD uniformity (LCDU). Here, we demonstrate a synergy of film stack deposition, EUV lithography, and plasma etch techniques to improve LCDU, which allows the use of high sensitivity resists required for the introduction of EUV HVM. Thus, to improve LCDU to a level required by 5 nm node and beyond, film stack deposition, EUV lithography, and plasma etch processes were combined and co-optimized to enhance LCDU reduction from synergies. Test wafers were created by depositing a pattern transfer stack on a substrate representative of a 5 nm node target layer. The pattern transfer stack consisted of an atomically smooth adhesion layer and two hardmasks and was deposited using the Lam VECTOR PECVD product family. These layers were designed to mitigate hole roughness, absorb out-of-band radiation, and provide additional outlets for etch to improve LCDU and control hole CD. These wafers were then exposed through an ASML NXE3350B EUV scanner using a variety of advanced positive tone EUV CAR. They were finally etched to the target substrate using Lam Flex dielectric etch and Kiyo conductor etch systems. Metrology methodologies to assess dimensional metrics as well as chip performance and defectivity were investigated to enable repeatable patterning process development. Illumination conditions in EUV lithography were optimized to improve normalized image log slope (NILS), which is expected to reduce shot noise related effects. It can be seen that the EUV imaging contrast improvement can further reduce post-develop LCDU from 4.1 nm to 3.9 nm and from 2.8 nm to 2.6 nm. In parallel, etch processes were developed to further reduce LCDU, to control CD, and to transfer these improvements into the final target substrate. We also demonstrate that increasing post-develop CD through dose adjustment can enhance the LCDU reduction from etch. Similar trends were also observed in different pitches down to 40 nm. The solutions demonstrated here are critical to the introduction of EUV lithography in high volume manufacturing. It can be seen that through a synergistic deposition, lithography, and etch optimization, LCDU at a 40 nm pitch can be improved to 1.6 nm (3-sigma) in a target oxide layer and to 1.4 nm (3-sigma) at the photoresist layer.

Extreme ultraviolet interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberg, Kenneth A.

EUV lithography is a promising and viable candidate for circuit fabrication with 0.1-micron critical dimension and smaller. In order to achieve diffraction-limited performance, all-reflective multilayer-coated lithographic imaging systems operating near 13-nm wavelength and 0.1 NA have system wavefront tolerances of 0.27 nm, or 0.02 waves RMS. Owing to the highly-sensitive resonant reflective properties of multilayer mirrors and extraordinarily tight tolerances set forth for their fabrication, EUV optical systems require at-wavelength EUV interferometry for final alignment and qualification. This dissertation discusses the development and successful implementation of high-accuracy EUV interferometric techniques. Proof-of-principle experiments with a prototype EUV point-diffraction interferometer for themore » measurement of Fresnel zoneplate lenses first demonstrated sub-wavelength EUV interferometric capability. These experiments spurred the development of the superior phase-shifting point-diffraction interferometer (PS/PDI), which has been implemented for the testing of an all-reflective lithographic-quality EUV optical system. Both systems rely on pinhole diffraction to produce spherical reference wavefronts in a common-path geometry. Extensive experiments demonstrate EUV wavefront-measuring precision beyond 0.02 waves RMS. EUV imaging experiments provide verification of the high-accuracy of the point-diffraction principle, and demonstrate the utility of the measurements in successfully predicting imaging performance. Complementary to the experimental research, several areas of theoretical investigation related to the novel PS/PDI system are presented. First-principles electromagnetic field simulations of pinhole diffraction are conducted to ascertain the upper limits of measurement accuracy and to guide selection of the pinhole diameter. Investigations of the relative merits of different PS/PDI configurations accompany a general study of the most significant sources of systematic measurement errors. To overcome a variety of experimental difficulties, several new methods in interferogram analysis and phase-retrieval were developed: the Fourier-Transform Method of Phase-Shift Determination, which uses Fourier-domain analysis to improve the accuracy of phase-shifting interferometry; the Fourier-Transform Guided Unwrap Method, which was developed to overcome difficulties associated with a high density of mid-spatial-frequency blemishes and which uses a low-spatial-frequency approximation to the measured wavefront to guide the phase unwrapping in the presence of noise; and, finally, an expedient method of Gram-Schmidt orthogonalization which facilitates polynomial basis transformations in wave-front surface fitting procedures.« less

THE INFLUENCE OF THE EXTREME ULTRAVIOLET SPECTRAL ENERGY DISTRIBUTION ON THE STRUCTURE AND COMPOSITION OF THE UPPER ATMOSPHERE OF EXOPLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, J. H.; Ben-Jaffel, Lotfi, E-mail: guojh@ynao.ac.cn, E-mail: bjaffel@iap.fr

2016-02-20

By varying the profiles of stellar extreme ultraviolet (EUV) spectral energy distributions (SEDs), we tested the influences of stellar EUV SEDs on the physical and chemical properties of an escaping atmosphere. We apply our model to study four exoplanets: HD 189733b, HD 209458b, GJ 436b, and Kepler-11b. We find that the total mass loss rates of an exoplanet, which are determined mainly by the integrated fluxes, are moderately affected by the profiles of the EUV SED, but the composition and species distributions in the atmosphere can be dramatically modified by the different profiles of the EUV SED. For exoplanets withmore » a high hydrodynamic escape parameter (λ), the amount of atomic hydrogen produced by photoionization at different altitudes can vary by one to two orders of magnitude with the variation of stellar EUV SEDs. The effect of photoionization of H is prominent when the EUV SED is dominated by the low-energy spectral region (400–900 Å), which pushes the transition of H/H{sup +} to low altitudes. In contrast, the transition of H/H{sup +} moves to higher altitudes when most photons are concentrated in the high-energy spectral region (50–400 Å). For exoplanets with a low λ, the lower temperatures of the atmosphere make many chemical reactions so important that photoionization alone can no longer determine the composition of the escaping atmosphere. For HD 189733b, it is possible to explain the time variability of Lyα between 2010 and 2011 by a change in the EUV SED of the host K-type star, yet invoking only thermal H i in the atmosphere.« less

CME Expansion as the Driver of Metric Type II Shock Emission as Revealed by Self-consistent Analysis of High-Cadence EUV Images and Radio Spectrograms

NASA Astrophysics Data System (ADS)

Kouloumvakos, A.; Patsourakos, S.; Hillaris, A.; Vourlidas, A.; Preka-Papadema, P.; Moussas, X.; Caroubalos, C.; Tsitsipis, P.; Kontogeorgos, A.

2014-06-01

On 13 June 2010, an eruptive event occurred near the solar limb. It included a small filament eruption and the onset of a relatively narrow coronal mass ejection (CME) surrounded by an extreme ultraviolet (EUV) wave front recorded by the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) at high cadence. The ejection was accompanied by a GOES M1.0 soft X-ray flare and a Type-II radio burst; high-resolution dynamic spectra of the latter were obtained by the Appareil de Routine pour le Traitement et l'Enregistrement Magnetique de l'Information Spectral (ARTEMIS IV) radio spectrograph. The combined observations enabled a study of the evolution of the ejecta and the EUV wave front and its relationship with the coronal shock manifesting itself as metric Type-II burst. By introducing a novel technique, which deduces a proxy of the EUV compression ratio from AIA imaging data and compares it with the compression ratio deduced from the band-split of the Type-II metric radio burst, we are able to infer the potential source locations of the radio emission of the shock on that AIA images. Our results indicate that the expansion of the CME ejecta is the source for both EUV and radio shock emissions. Early in the CME expansion phase, the Type-II burst seems to originate in the sheath region between the EUV bubble and the EUV shock front in both radial and lateral directions. This suggests that both the nose and the flanks of the expanding bubble could have driven the shock.

Enhancement of EUV emission from a liquid microjet target by use of dual laser pulses

NASA Astrophysics Data System (ADS)

Higashiguchi, Takeshi; Rajyaguru, Chirag; Koga, Masato; Kawasaki, Keita; Sasaki, Wataru; Kubodera, Shoichi; Kikuchi, Takashi; Yugami, Noboru; Kawata, Shigeo; Andreev, Alexander A.

2005-03-01

Extreme ultraviolet (EUV) radiation at the wavelength of around 13nm waws observed from a laser-produced plasma using continuous water-jet. Strong dependence of the conversion efficiency (CE) on the laser focal spot size and jet diameter was observed. The EUV CE at a given laser spot size and jet diameter was further enhanced using double laser pulses, where a pre-pulse was used for initial heating of the plasma.

Extreme ultraviolet spectroscopy of low pressure helium microwave driven discharges

NASA Astrophysics Data System (ADS)

Espinho, Susana; Felizardo, Edgar; Tatarova, Elena; Alves, Luis Lemos

2016-09-01

Surface wave driven discharges are reliable plasma sources that can produce high levels of vacuum and extreme ultraviolet radiation (VUV and EUV). The richness of the emission spectrum makes this type of discharge a possible alternative source in EUV/VUV radiation assisted applications. However, due to challenging experimental requirements, publications concerning EUV radiation emitted by microwave plasmas are scarce and a deeper understanding of the main mechanisms governing the emission of radiation in this spectral range is required. To this end, the EUV radiation emitted by helium microwave driven plasmas operating at 2.45 GHz has been studied for low pressure conditions. Spectral lines from excited helium atoms and ions were detected via emission spectroscopy in the EUV/VUV regions. Novel data concerning the spectral lines observed in the 23 - 33 nm wavelength range and their intensity behaviour with variation of the discharge operational conditions are presented. The intensity of all the spectral emissions strongly increases with the microwave power delivered to the plasma up to 400 W. Furthermore, the intensity of all the ion spectral emissions in the EUV range decreases by nearly one order of magnitude as the pressure was raised from 0.2 to 0.5 mbar. Work funded by FCT - Fundacao para a Ciencia e a Tecnologia, under Project UID/FIS/50010/2013 and grant SFRH/BD/52412/2013 (PD-F APPLAuSE).

Recent solar extreme ultraviolet irradiance observations and modeling: A review

NASA Technical Reports Server (NTRS)

Tobiska, W. Kent

1993-01-01

For more than 90 years, solar extreme ultraviolet (EUV) irradiance modeling has progressed from empirical blackbody radiation formulations, through fudge factors, to typically measured irradiances and reference spectra was well as time-dependent empirical models representing continua and line emissions. A summary of recent EUV measurements by five rockets and three satellites during the 1980s is presented along with the major modeling efforts. The most significant reference spectra are reviewed and threee independently derived empirical models are described. These include Hinteregger's 1981 SERF1, Nusinov's 1984 two-component, and Tobiska's 1990/1991/SERF2/EUV91 flux models. They each provide daily full-disk broad spectrum flux values from 2 to 105 nm at 1 AU. All the models depend to one degree or another on the long time series of the Atmosphere Explorer E (AE-E) EUV database. Each model uses ground- and/or space-based proxies to create emissions from solar atmospheric regions. Future challenges in EUV modeling are summarized including the basic requirements of models, the task of incorporating new observations and theory into the models, the task of comparing models with solar-terrestrial data sets, and long-term goals and modeling objectives. By the late 1990s, empirical models will potentially be improved through the use of proposed solar EUV irradiance measurements and images at selected wavelengths that will greatly enhance modeling and predictive capabilities.

Distinct EUV minimum of the solar irradiance (16-40 nm) observed by SolACES spectrometers onboard the International Space Station (ISS) in August/September 2009

NASA Astrophysics Data System (ADS)

Nikutowski, B.; Brunner, R.; Erhardt, Ch.; Knecht, St.; Schmidtke, G.

2011-09-01

In the field of terrestrial climatology the continuous monitoring of the solar irradiance with highest possible accuracy is an important goal. SolACES as a part of the ESA mission SOLAR on the ISS is measuring the short-wavelength solar EUV irradiance from 16-150 nm. This data will be made available to the scientific community to investigate the impact of the solar irradiance variability on the Earth's climate as well as the thermospheric/ionospheric interactions that are pursued in the TIGER program. Since the successful launch with the shuttle mission STS-122 on February 7th, 2008, SolACES initially recorded the low EUV irradiance during the extended solar activity minimum. Thereafter it has been observing the EUV irradiance during the increasing solar activity with enhanced intensity and changing spectral composition. SolACES consists of three grazing incidence planar grating spectrometers. In addition there are two three-signal ionisation chambers, each with exchangeable band-pass filters to determine the absolute EUV fluxes repeatedly during the mission. One important problem of space-borne instrumentation recording the solar EUV irradiance is the degradation of the spectrometer sensitivity. The two double ionisation chambers of SolACES, which could be re-filled with three different gases for each recording, allow the recalibration of the efficiencies of the three SolACES spectrometers from time to time.

Surface phenomena related to mirror degradation in extreme ultraviolet (EUV) lithography

NASA Astrophysics Data System (ADS)

Madey, Theodore E.; Faradzhev, Nadir S.; Yakshinskiy, Boris V.; Edwards, N. V.

2006-12-01

One of the most promising methods for next generation device manufacturing is extreme ultraviolet (EUV) lithography, which uses 13.5 nm wavelength radiation generated from freestanding plasma-based sources. The short wavelength of the incident illumination allows for a considerable decrease in printed feature size, but also creates a range of technological challenges not present for traditional optical lithography. Contamination and oxidation form on multilayer reflecting optics surfaces that not only reduce system throughput because of the associated reduction in EUV reflectivity, but also introduce wavefront aberrations that compromise the ability to print uniform features. Capping layers of ruthenium, films ∼2 nm thick, are found to extend the lifetime of Mo/Si multilayer mirrors used in EUV lithography applications. However, reflectivities of even the Ru-coated mirrors degrade in time during exposure to EUV radiation. Ruthenium surfaces are chemically reactive and are very effective as heterogeneous catalysts. In the present paper we summarize the thermal and radiation-induced surface chemistry of bare Ru exposed to gases; the emphasis is on H2O vapor, a dominant background gas in vacuum processing chambers. Our goal is to provide insights into the fundamental physical processes that affect the reflectivity of Ru-coated Mo/Si multilayer mirrors exposed to EUV radiation. Our ultimate goal is to identify and recommend practices or antidotes that may extend mirror lifetimes.

An investigation of solar erythemal ultraviolet radiation at two sites in tourist attraction areas of Thailand

NASA Astrophysics Data System (ADS)

Buntoung, Sumaman; Pattarapanitchai, Somjet; Wattan, Rungrat; Masiri, Itsara; Promsen, Worrapass; Tohsing, Korntip; Janjai, Serm

2013-05-01

Islands on the southern coasts of Thailand are famous attractions for local and foreign tourists. Tourists usually expose their skins to solar radiation for tanning. Thus information on solar ultraviolet radiation (UV) is of importance for tourists to protect themselves from adverse effects of UV. In this work, solar erythemal ultraviolet radiation (EUV) at two touristic sites namely Samui island (9.451°N, 100.033°E) and Phuket island (8.104°N, 98.304°E) was investigated. In investigating EUV, broadband UV radiometers (Kipp & Zonen, model UVS-B-C) were installed at existing meteorological stations in Samui and Phuket islands. A one-year period of EUV data from these two sites was analyzed. The level of UV index at these sites was studied. The values of UV index higher than 12 at noon time of clear days are usually found in the summer at both sites. Seasonal variation of EUV at both sites was investigated. It was found that the tropical monsoons have strong influence on this variation. Finally, global broadband radiation measured at the sites was also used to establish a correlation between EUV and global broadband radiation. Higher correlation was found for the case of clear sky, as compared to the case of cloudy sky. The correlation obtained from this analysis can be used to estimate EUV from global broadband radiation at these two sites.

Spherical EUV and Plasma Spectrometer (seps) -a Monitor to Measure the Plasma and EUV Environment in Space

NASA Astrophysics Data System (ADS)

Brunner, Raimund; Schmidtke, Gerhard; Konz, Werner; Pfeffer, Wilfried

A low-cost monitor to measure the EUV and plasma environment in space is presented. The device consists of three (or more) isolated spheres, a metallic sphere, one or more highly trans-parent Inner Grids and Outer Grids. Each one is being connected to a sensitive floating elec-trometer. By setting different potentials to the grids as well as to the sphere and varying one or more of their voltages, measurements of spectral solar EUV irradiance (15-200 nm), of local plasma parameters such as electron and ion densities, electron energies and temperatures as well as ion compositions and debris events can be derived from the current recordings. This detector does not require any (solar) pointing device. The primary goal is to study the impact of solar activity events (e.g. CMEs) as well as subsequent reactions of the ionospheric/thermospheric systems (including space weather occurences). The capability of SEPS for measuring EUV pho-ton fluxes as well as plasma parameters in the energy range from 0 to +/-70 eV is demonstrated by laboratory measurements as performed in the IPM laboratory, at BESSY-PTB electron syn-chrotron in Berlin and at ESA/ESTEC plasma chamber. Based on the laboratory recording of plasma recombination EUV emission the sensor is suitable to detect also auroral and airglow radiations. -The state of the art in the development of this device is reported.

Laser-plasma extreme ultraviolet and soft X-ray sources based on a double stream gas puff target: interaction of the radiation pulses with matter

NASA Astrophysics Data System (ADS)

Bartnik, A.

2015-06-01

In this work a review of investigations concerning interaction of intense extreme ultraviolet (EUV) and soft X-ray (SXR) pulses with matter is presented. The investigations were performed using laser-produced plasma (LPP) EUV/SXR sources based on a double stream gas puff target. The sources are equipped with dedicated collectors allowing for efficient focusing of the EUV/SXR radiation pulses. Intense radiation in a wide spectral range, as well as a quasi-monochromatic radiation can be produced. In the paper different kinds of LPP EUV/SXR sources developed in the Institute of Optoelectronics, Military University of Technology are described. Radiation intensities delivered by the sources are sufficient for different kinds of interaction experiments including EUV/SXR induced ablation, surface treatment, EUV fluorescence or photoionized plasma creation. A brief review of the main results concerning this kind of experiments performed by author of the paper are presented. However, since the LPP sources cannot compete with large scale X-ray sources like synchrotrons, free electron lasers or high energy density plasma sources, it was indicated that some investigations not requiring extreme irradiation parameters can be performed using the small scale installations. Some results, especially concerning low temperature photoionized plasmas are very unique and could be hardly obtained using the large facilities.

The Origin of the EUV Emission in Her X-1

NASA Technical Reports Server (NTRS)

Leahy, D. A.; Marshall, H.

1999-01-01

Her X-1 exhibits a strong orbital modulation of its EUV flux with a large decrease around time of eclipse of the neutron star, and a significant dip which appears at different orbital phases at different 35-day phases. We consider observations of Her X-1 in the EUVE by the Extreme Ultraviolet Explorer (EUVE), which includes data from 1995 near the end of the Short High state, and date from 1997 at the start of the Short High state. The observed EUV lightcurve has bright and faint phases. The bright phase can be explained as the low energy tail of the soft x-ray pulse. The faint phase emission has been modeled to understand its origin. We find: the x-ray heated surface of HZ Her is too cool to produce enough emission; the accretion disk does not explain the orbital modulation; however, reflection of x-rays off of HZ Her can produce the observed lightcurve with orbital eclipses. The dip can be explained by shadowing of the companion by the accretion disk. We discuss the constraints on the accretion disk geometry derived from the observed shadowing.

Detection of significant differences between absorption spectra of neutral helium and low temperature photoionized helium plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartnik, A.; Wachulak, P.; Fiedorowicz, H.

2013-11-15

In this work, spectral investigations of photoionized He plasmas were performed. The photoionized plasmas were created by irradiation of helium stream, with intense pulses from laser-plasma extreme ultraviolet (EUV) source. The EUV source was based on a double-stream Xe/Ne gas-puff target irradiated with 10 ns/10 J Nd:YAG laser pulses. The most intense emission from the source spanned a relatively narrow spectral region below 20 nm, however, spectrally integrated intensity at longer wavelengths was also significant. The EUV radiation was focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulse. The long-wavelength part of the EUVmore » radiation was used for backlighting of the photoionized plasmas to obtain absorption spectra. Both emission and absorption spectra in the EUV range were investigated. Significant differences between absorption spectra acquired for neutral helium and low temperature photoionized plasmas were demonstrated for the first time. Strong increase of intensities and spectral widths of absorption lines, together with a red shift of the K-edge, was shown.« less

Relationship between hard X-ray and EUV sources in solar flares

NASA Technical Reports Server (NTRS)

Kane, S. R.; Frost, K. J.; Donnelly, R. F.

1979-01-01

The high time resolution hard X-ray (not less than 15 keV) observations of medium and large impulsive solar flares made with the OSO 5 satellite are compared with the simultaneous ground-based observations of 10-1030 A EUV flux made via sudden frequency deviations (SFD) at Boulder. For most flares the agreement between the times of maxima of the impulsive hard X-ray and EUV emissions is found to be consistent with earlier studies (not less than 1 s). The rise and decay times of the EUV emission are larger than the corresponding times for X-rays not less than 30 keV. When OSO 5 hard X-ray measurements are combined with those made by OGO1, OGO 3, OGO 5, and TD 1A satellites, it is found that there is a nearly linear relationship between the energy fluxes of impulsive EUV emission and X-rays not less than 10 keV over a wide range of flare magnitudes. A model involving only a 'partial precipitation' of energetic electrons and consisting of both thick and thin target hard X-ray sources is examined.

Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold

PubMed Central

Makhotkin, Igor A.; Sobierajski, Ryszard; Chalupský, Jaromir; Tiedtke, Kai; de Vries, Gosse; Störmer, Michael; Scholze, Frank; Siewert, Frank; van de Kruijs, Robbert W. E.; Milov, Igor; Louis, Eric; Jacyna, Iwanna; Jurek, Marek; Klinger, Dorota; Syryanyy, Yevgen; Juha, Libor; Hájková, Věra; Saksl, Karel; Faatz, Bart; Keitel, Barbara; Plönjes, Elke; Toleikis, Sven; Loch, Rolf; Hermann, Martin; Strobel, Sebastian; Nienhuys, Han-Kwang; Gwalt, Grzegorz; Mey, Tobias; Enkisch, Hartmut

2018-01-01

The durability of grazing- and normal-incidence optical coatings has been experimentally assessed under free-electron laser irradiation at various numbers of pulses up to 16 million shots and various fluence levels below 10% of the single-shot damage threshold. The experiment was performed at FLASH, the Free-electron LASer in Hamburg, using 13.5 nm extreme UV (EUV) radiation with 100 fs pulse duration. Polycrystalline ruthenium and amorphous carbon 50 nm thin films on silicon substrates were tested at total external reflection angles of 20° and 10° grazing incidence, respectively. Mo/Si periodical multilayer structures were tested in the Bragg reflection condition at 16° off-normal angle of incidence. The exposed areas were analysed post-mortem using differential contrast visible light microscopy, EUV reflectivity mapping and scanning X-ray photoelectron spectroscopy. The analysis revealed that Ru and Mo/Si coatings exposed to the highest dose and fluence level show a few per cent drop in their EUV reflectivity, which is explained by EUV-induced oxidation of the surface. PMID:29271755

Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold.

PubMed

Makhotkin, Igor A; Sobierajski, Ryszard; Chalupský, Jaromir; Tiedtke, Kai; de Vries, Gosse; Störmer, Michael; Scholze, Frank; Siewert, Frank; van de Kruijs, Robbert W E; Milov, Igor; Louis, Eric; Jacyna, Iwanna; Jurek, Marek; Klinger, Dorota; Nittler, Laurent; Syryanyy, Yevgen; Juha, Libor; Hájková, Věra; Vozda, Vojtěch; Burian, Tomáš; Saksl, Karel; Faatz, Bart; Keitel, Barbara; Plönjes, Elke; Schreiber, Siegfried; Toleikis, Sven; Loch, Rolf; Hermann, Martin; Strobel, Sebastian; Nienhuys, Han Kwang; Gwalt, Grzegorz; Mey, Tobias; Enkisch, Hartmut

2018-01-01

The durability of grazing- and normal-incidence optical coatings has been experimentally assessed under free-electron laser irradiation at various numbers of pulses up to 16 million shots and various fluence levels below 10% of the single-shot damage threshold. The experiment was performed at FLASH, the Free-electron LASer in Hamburg, using 13.5 nm extreme UV (EUV) radiation with 100 fs pulse duration. Polycrystalline ruthenium and amorphous carbon 50 nm thin films on silicon substrates were tested at total external reflection angles of 20° and 10° grazing incidence, respectively. Mo/Si periodical multilayer structures were tested in the Bragg reflection condition at 16° off-normal angle of incidence. The exposed areas were analysed post-mortem using differential contrast visible light microscopy, EUV reflectivity mapping and scanning X-ray photoelectron spectroscopy. The analysis revealed that Ru and Mo/Si coatings exposed to the highest dose and fluence level show a few per cent drop in their EUV reflectivity, which is explained by EUV-induced oxidation of the surface.

Studies on cryogenic Xe capillary jet target for laser-produced plasma EUV-light source

NASA Astrophysics Data System (ADS)

Inoue, T.; Nica, P. E.; Kaku, K.; Shimoura, A.; Amano, S.; Miyamoto, S.; Mochizuki, T.

2006-03-01

In this paper, characterizations of a cryogenic Xe capillary jet target for a laser-produced plasma extreme ultraviolet (EUV) light source are reported. The capillary jet target is a candidate of fast-supplying targets for mitigating debris generation and target consumption in a vacuum chamber without reducing the EUV conversion efficiency. Xe capillary jets (jet velocity ~ 0.4 m/s) were generated in vacuum by using annular nozzles chilled to ~ 170 K at a Xe backing pressure of ~ 0.7 MPa. Forming mechanisms of the capillary jet targets were studied by using numerical calculations. Furthermore, laser-produced plasma EUV generation was performed by irradiating a Nd:YAG laser (1064 nm, ~ 0.5 J, 10 ns, 120 μmφ, ~ 4×10 11 W/cm2) on a Xe capillary jet target (outer / inner diameter = 100 / 70 μmφ). The angular distribution of EUV generation was approximately uniform around the Xe capillary jet target, and the peak kinetic energy of the fast-ions was evaluated to be ~ 2 keV.

EUV multilayer coatings for the Atmospheric Imaging Assembly instrument aboard the Solar Dynamics Observatory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soufli, R; Windt, D L; Robinson, J C

2006-02-09

Multilayer coatings for the 7 EUV channels of the AIA have been developed and completed successfully on all AIA flight mirrors. Mo/Si coatings (131, 171, 193.5, 211 {angstrom}) were deposited at Lawrence Livermore National Laboratory (LLNL). Mg/SiC (304, 335 {angstrom}) and Mo/Y (94 {angstrom}) coatings were deposited at Columbia University. EUV reflectance of the 131/335 {angstrom}, 171 {angstrom}, 193.5/211 {angstrom} primary and secondary flight mirrors and the 94/304 {angstrom} secondary flight mirror was measured at beamline 6.3.2. of the Advanced Light Source (ALS) at LBNL. EUV reflectance of the 94/304 {angstrom} primary and secondary flight mirrors was measured at beamlinemore » X24C of the National Synchrotron Light Source (NSLS) at Brookhaven National Lab. Preliminary EUV reflectance measurements of the 94, 304 and 335 {angstrom} coatings were performed with a laser plasma source reflectometer located at Columbia University. Prior to multilayer coating, Atomic Force Microscopy (AFM) characterization and cleaning of all flight substrates was performed at LLNL.« less

Overview of Key Results from SDO Extreme ultraviolet Variability Experiment (EVE)

NASA Astrophysics Data System (ADS)

Woods, Tom; Eparvier, Frank; Jones, Andrew; Mason, James; Didkovsky, Leonid; Chamberlin, Phil

2016-10-01

The SDO Extreme ultraviolet Variability Experiment (EVE) includes several channels to observe the solar extreme ultraviolet (EUV) spectral irradiance from 1 to 106 nm. These channels include the Multiple EUV Grating Spectrograph (MEGS) A, B, and P channels from the University of Colorado (CU) and the EUV SpectroPhometer (ESP) channels from the University of Southern California (USC). The solar EUV spectrum is rich in many different emission lines from the corona, transition region, and chromosphere. The EVE full-disk irradiance spectra are important for studying the solar impacts in Earth's ionosphere and thermosphere and are useful for space weather operations. In addition, the EVE observations, with its high spectral resolution of 0.1 nm and in collaboration with AIA solar EUV images, have proven valuable for studying active region evolution and explosive energy release during flares and coronal eruptions. These SDO measurements have revealed interesting results such as understanding the flare variability over all wavelengths, discovering and classifying different flare phases, using coronal dimming measurements to predict CME properties of mass and velocity, and exploring the role of nano-flares in continual heating of active regions.

The Extreme Ultraviolet Explorer Mission

NASA Technical Reports Server (NTRS)

Bowyer, S.; Malina, R. F.

1991-01-01

The Extreme Ultraviolet Explorer (EUVE) mission, currently scheduled from launch in September 1991, is described. The primary purpose of the mission is to survey the celestial sphere for astronomical sources of extreme ultraviolet (EUV) radiation with the use of three EUV telescope, each sensitive to a different segment of the EUV band. A fourth telescope is planned to perform a high-sensitivity search of a limited sample of the sky in the shortest wavelength bands. The all-sky survey is planned to be carried out in the first six months of the mission in four bands, or colors, 70-180 A, 170-250 A, 400-600 A, and 500-700 A. The second phase of the mission is devoted to spectroscopic observations of EUV sources. A high-efficiency grazing-incidence spectrometer using variable line-space gratings is planned to provide spectral data with about 1-A resolution. An end-to-end model of the mission, from a stellar source to the resulting scientific data, is presented. Hypothetical data from astronomical sources were processed through this model and are shown.

Deposition, characterization, patterning and mechanistic study of inorganic resists for next-generation nanolithography

NASA Astrophysics Data System (ADS)

Luo, Feixiang

The semiconductor industry has witnessed a continuous decrease in the size of logic, memory and other computer chip components since its birth over half a century ago. The shrinking (scaling) of components has to a large extent been enabled by the development of micro- and now nano-lithographic techniques. This thesis focuses on one central component of lithography, the resist, which is essentially a thin film that when appropriately exposed enables a pattern to be printed onto a surface. Smaller features require an ever more precisely focused photon, electron or ion beam with which to expose the resist. The likely next generation source of radiation that will enable sub-20nm features to be written will employ extreme ultraviolet radiation (EUV), 92eV (13.5nm). The work discussed here involves a novel class of inorganic resists (including a solution processed Hf-based resist called HafSOx), as the organic resists that have dominated the microlithography industry for the past few decades have approached fundamental scaling limits. In order to maintain the high throughput required by high volume semiconductor manufacturing, metal oxide resists have been proposed and developed to meet the resolution and sensitivity in EUV lithography. One can think of our resists as the nano-lithographic analog to the silver halide film that dominated the photographic print industry for a century. In this thesis, we mainly describe our work on HafSOx, a "first generation" metal oxide EUV resist system. HafSOx thin films can be deposited by spin-coating a mixed solution of HfOCl2, H2O 2, and H2SO4. Various materials characterization techniques have been employed to achieve a comprehensive understanding of film composition and structure at both surface and bulk level, as well as a mechanistic understanding of the film radiation chemistry. Taking advantage of the high energy x-rays used in the XPS experiment, we developed an experiment to dynamically monitor the photochemistry within the HafSOx films. Based on this experiment, we found that an insoluble Hf-O-Hf network is eventually formed after film exposure and development by the removal of SOx, OH, and H2O, and the cross-linking of HfxOy nanoparticles. Using photoemission and complementary Raman results, and knowing that both free and bound peroxide co-exist in the precursor solution, we confirmed that there is a specific peroxide stoichiometry needed in the film to chelate to Hf. Sulfate groups were found to act as the spacers between metal oxide nanoparticles to prevent early stage nanoparticle aggregation in the as-deposited films. Too much sulfate sacrifices resist sensitivity, while too little promotes undesired nanoparticle cross-linking during film preparation. In EUV lithography, low energy secondary electron activation had been suggested as a mechanism explaining how film exposure to EUV photons through a mask can result in a patterned film, but this hypothesis lacked experimental evidence. We constructed a low energy electron beam exposure system, exposed HafSOx resists with electrons with energy ranging from 2 eV to 100 eV, and then characterized the film changes after the exposure. Surprisingly, we found electrons with an energy as low as 2 eV can activate the film if given a sufficient electron dose. Electrons with a lower energy require higher doses to fully activate the resist. Our results strongly support the hypothesis that relatively low energy secondary electrons are central in the mechanism responsible for patterning, in this case by interacting with peroxyl species bound to Hf in the films. With the recent arrival of a state-of-art Zeiss-Orion helium ion beam microscope at Rutgers, we also tested the patterning performance of a HafSOx resist with 30 keV He+ ions. (HIBL = helium ion beam lithography). 30 keV He ions were found to be 50-100 more sensitive than 30 keV electrons at patterning HafSOx, and this boost was attributed to the higher stopping power of helium ions compared with electrons. Sub-10 nm critical dimensions were achieved with fairly good line edge roughness (a key metric in assessing lithographic performance). Additionally, Monte Carlo simulations were conducted to compare the ion and electron trajectories in the solid films and to investigate energy loss in the HafSOx films. In summary, a systematic approach has been developed to understand the mechanism behind HafSOx as an EUV resist. Our work helps lead to a more comprehensive mechanistic understanding of how metal oxide EUV photoresists work in general, and suggests ways to optimize their performance.

A stand-alone compact EUV microscope based on gas-puff target source.

PubMed

Torrisi, Alfio; Wachulak, Przemyslaw; Węgrzyński, Łukasz; Fok, Tomasz; Bartnik, Andrzej; Parkman, Tomáš; Vondrová, Šárka; Turňová, Jana; Jankiewicz, Bartłomiej J; Bartosewicz, Bartosz; Fiedorowicz, Henryk

2017-02-01

We report on a very compact desk-top transmission extreme ultraviolet (EUV) microscope based on a laser-plasma source with a double stream gas-puff target, capable of acquiring magnified images of objects with a spatial (half-pitch) resolution of sub-50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi-monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed. Test object and other samples were imaged to demonstrate superior resolution compared to visible light microscopy. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

An EUV Study of the Eclipsing M-Dwarf Binary System YY GEM

NASA Technical Reports Server (NTRS)

Drake, Jeremy

2000-01-01

EUVE, SW, MW and LW spectra have been reduced and line fluxes measured. The Deep Survey data has been analyzed and light curves have been derived. The spectra around the HE II 304 region show some evidence of emission from the bright A companion star, Castor. Preliminary results for the metallicity of the corona of YY Gem were derived from the EUVE spectra and photometry and were presented at the AAS HEAD meeting; results are being finalized for publication in a referred journal.

Cleaning process for EUV optical substrates

DOEpatents

Weber, Frank J.; Spiller, Eberhard A.

1999-01-01

A cleaning process for surfaces with very demanding cleanliness requirements, such as extreme-ultraviolet (EUV) optical substrates. Proper cleaning of optical substrates prior to applying reflective coatings thereon is very critical in the fabrication of the reflective optics used in EUV lithographic systems, for example. The cleaning process involves ultrasonic cleaning in acetone, methanol, and a pH neutral soap, such as FL-70, followed by rinsing in de-ionized water and drying with dry filtered nitrogen in conjunction with a spin-rinse.

Slowly varying component of extreme ultraviolet solar radiation and its relation to solar radio radiation

NASA Technical Reports Server (NTRS)

Chapman, R. D.; Neupert, W. M.

1974-01-01

A study of the correlations between solar EUV line fluxes and solar radio fluxes has been carried out. A calibration for the Goddard Space Flight Center EUV spectrum is suggested. The results are used to obtain an equation for the absolute EUV flux for several lines in the 150- to 400-A region and the total flux of 81 intense lines in the region, the 2800-MHz radio flux being used as independent variable.

Monitoring of solar far ultraviolet radiation from the OSO-5 satellite

NASA Technical Reports Server (NTRS)

Rense, W. A.; Parker, R.

1972-01-01

A spectrophotometer for monitoring the solar EUV in three broad wavelength bands is described. The kind of data obtained, along with sources of error, are presented. The content of the tape library which contains the data is outlined. The scientific results are discussed. These include the following: solar flares in the EUV, solar eclipse observations in the EUV, SFD's and relationship to solar flares, and the application of satellite sunrise and sunset data for the study of model upper atmospheres for the earth.

The creation of radiation dominated plasmas using laboratory extreme ultra-violet lasers

NASA Astrophysics Data System (ADS)

Tallents, G. J.; Wilson, S.; West, A.; Aslanyan, V.; Lolley, J.; Rossall, A. K.

2017-06-01

Ionization in experiments where solid targets are irradiated by high irradiance extreme ultra-violet (EUV) lasers is examined. Free electron degeneracy effects on ionization in the presence of a high EUV flux of radiation is shown to be important. Overlap of the physics of such plasmas with plasma material under compression in indirect inertial fusion is explored. The design of the focusing optics needed to achieve high irradiance (up to 1014 Wcm-2) using an EUV capillary laser is presented.

Well-defined EUV wave associated with a CME-driven shock

NASA Astrophysics Data System (ADS)

Cunha-Silva, R. D.; Selhorst, C. L.; Fernandes, F. C. R.; Oliveira e Silva, A. J.

2018-05-01

Aims: We report on a well-defined EUV wave observed by the Extreme Ultraviolet Imager (EUVI) on board the Solar Terrestrial Relations Observatory (STEREO) and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The event was accompanied by a shock wave driven by a halo CME observed by the Large Angle and Spectrometric Coronagraph (LASCO-C2/C3) on board the Solar and Heliospheric Observatory (SOHO), as evidenced by the occurrence of type II bursts in the metric and dekameter-hectometric wavelength ranges. We investigated the kinematics of the EUV wave front and the radio source with the purpose of verifying the association between the EUV wave and the shock wave. Methods: The EUV wave fronts were determined from the SDO/AIA images by means of two appropriate directions (slices). The heights (radial propagation) of the EUV wave observed by STEREO/EUVI and of the radio source associated with the shock wave were compared considering the whole bandwidth of the harmonic lane of the radio emission, whereas the speed of the shock was estimated using the lowest frequencies of the harmonic lane associated with the undisturbed corona, using an appropriate multiple of the Newkirk (1961, ApJ, 133, 983) density model and taking into account the H/F frequency ratio fH/fF = 2. The speed of the radio source associated with the interplanetary shock was determined using the Mann et al. (1999, A&A, 348, 614) density model. Results: The EUV wave fronts determined from the SDO/AIA images revealed the coexistence of two types of EUV waves, a fast one with a speed of 560 km s-1, and a slower one with a speed of 250 km s-1, which corresponds approximately to one-third of the average speed of the radio source ( 680 km s-1). The radio signature of the interplanetary shock revealed an almost constant speed of 930 km s-1, consistent with the linear speed of the halo CME (950 km s-1) and with the values found for the accelerating coronal shock ( 535-823 km s-1), taking into account the gap between the radio emissions.

Stability and imaging of the ASML EUV alpha demo tool

NASA Astrophysics Data System (ADS)

Hermans, Jan V.; Baudemprez, Bart; Lorusso, Gian; Hendrickx, Eric; van Dijk, Andre; Jonckheere, Rik; Goethals, Anne-Marie

2009-03-01

Extreme Ultra-Violet (EUV) lithography is the leading candidate for semiconductor manufacturing of the 22nm technology node and beyond, due to the very short wavelength of 13.5nm. However, reducing the wavelength adds complexity to the lithographic process. The impact of the EUV specific conditions on lithographic performance needs to be understood, before bringing EUV lithography into pre-production. To provide early learning on EUV, an EUV fullfield scanner, the Alpha Demo Tool (ADT) from ASML was installed at IMEC, using a Numerical Aperture (NA) of 0.25. In this paper we report on different aspects of the ADT: the imaging and overlay performance and both short and long-term stability. For 40nm dense Lines-Spaces (LS), the ADT shows an across field overlapping process window of 270nm Depth Of Focus (DOF) at 10% Exposure Latitude (EL) and a wafer CD Uniformity (CDU) of 3nm 3σ, without any corrections for process or reticle. The wafer CDU is correlated to different factors that are known to influence the CD fingerprint from traditional lithography: slit intensity uniformity, focus plane deviation and reticle CD error. Taking these contributions into account, the CD through slit fingerprint for 40nm LS is simulated with excellent agreement to experimental data. The ADT shows good CD stability over 9 months of operation, both intrafield and across wafer. The projection optics reflectivity has not degraded over 9 months. Measured overlay performance with respect to a dry tool shows |Mean|+3σ below 20nm with more correction potential by applying field-by-field corrections (|Mean|+3σ <=10nm). For 22nm SRAM application, both contact hole and metal layer were printed in EUV with 10% CD and 15nm overlay control. Below 40nm, the ADT shows good wafer CDU for 30nm dense and isolated lines (on the same wafer) and 38nm dense Contact Holes (CH). First 28nm dense line CDU data are achieved. The results indicate that the ADT can be used effectively for EUV process development before installation of the pre-production tool, the ASML NXE Gen. 1 at IMEC.

Photomask quality evaluation using lithography simulation and precision SEM image contour data

NASA Astrophysics Data System (ADS)

Murakawa, Tsutomu; Fukuda, Naoki; Shida, Soichi; Iwai, Toshimichi; Matsumoto, Jun; Nakamura, Takayuki; Hagiwara, Kazuyuki; Matsushita, Shohei; Hara, Daisuke; Adamov, Anthony

2012-11-01

To evaluate photomask quality, the current method uses spatial imaging by optical inspection tools. This technique at 1Xnm node has a resolution limit because small defects will be difficult to extract. To simulate the mask error-enhancement factor (MEEF) influence for aggressive OPC in 1Xnm node, wide FOV contour data and tone information are derived from high precision SEM images. For this purpose we have developed a new contour data extraction algorithm with sub-nanometer accuracy resulting in a wide Field of View (FOV) SEM image: (for example, more than 10um x 10um square). We evaluated MEEF influence of high-end photomask pattern using the wide FOV contour data of "E3630 MVM-SEMTM" and lithography simulator "TrueMaskTM DS" of D2S, Inc. As a result, we can detect the "invisible defect" as the MEEF influence using the wide FOV contour data and lithography simulator.

Defining defect specifications to optimize photomask production and requalification

NASA Astrophysics Data System (ADS)

Fiekowsky, Peter

2006-10-01

Reducing defect repairs and accelerating defect analysis is becoming more important as the total cost of defect repairs on advanced masks increases. Photomask defect specs based on printability, as measured on AIMS microscopes has been used for years, but the fundamental defect spec is still the defect size, as measured on the photomask, requiring the repair of many unprintable defects. ADAS, the Automated Defect Analysis System from AVI is now available in most advanced mask shops. It makes the use of pure printability specs, or "Optimal Defect Specs" practical. This software uses advanced algorithms to eliminate false defects caused by approximations in the inspection algorithm, classify each defect, simulate each defect and disposition each defect based on its printability and location. This paper defines "optimal defect specs", explains why they are now practical and economic, gives a method of determining them and provides accuracy data.

STS-96 M.S. Tokarev tries gas mask as part of a TCDT

NASA Technical Reports Server (NTRS)

1999-01-01

STS-96 Mission Specialist Valery Ivanovich Tokarev, with the Russian Space Agency, tries on an oxygen gas mask during Terminal Countdown Demonstration Test (TCDT) activities at Launch Pad 39B. The TCDT provides the crew with simulated countdown exercises, emergency egress training and opportunities to inspect the mission payloads in the orbiter's payload bay. Other crew members taking part in the TCDT are Commander Kent V. Rominger, Pilot Rick Douglas Husband, and Mission Specialists Tamara E. Jernigan (Ph.D.), Daniel Barry (M.D., Ph.D.), Ellen Ochoa (Ph.D.) and Julie Payette, with the Canadian Space Agency. Scheduled for liftoff on May 20 at 9:32 a.m., STS-96 is a logistics and resupply mission for the International Space Station, carrying such payloads as a Russian crane, the Strela; a U.S.-built crane; the Spacehab Oceaneering Space System Box (SHOSS), a logistics items carrier; and STARSHINE, a student-led experiment.

Enhancement of the MODIS Snow and Ice Product Suite Utilizing Image Segmentation

NASA Technical Reports Server (NTRS)

Tilton, James C.; Hall, Dorothy K.; Riggs, George A.

2006-01-01

A problem has been noticed with the current NODIS Snow and Ice Product in that fringes of certain snow fields are labeled as "cloud" whereas close inspection of the data indicates that the correct labeling is a non-cloud category such as snow or land. This occurs because the current MODIS Snow and Ice Product generation algorithm relies solely on the MODIS Cloud Mask Product for the labeling of image pixels as cloud. It is proposed here that information obtained from image segmentation can be used to determine when it is appropriate to override the cloud indication from the cloud mask product. Initial tests show that this approach can significantly reduce the cloud "fringing" in modified snow cover labeling. More comprehensive testing is required to determine whether or not this approach consistently improves the accuracy of the snow and ice product.

Physical Conditions in the Solar Corona Derived from the Total Solar Eclipse Observations obtained on 2017 August 21 Using a Polarization Camera

NASA Astrophysics Data System (ADS)

Gopalswamy, N.; Yashiro, Seiji; Reginald, Nelson; Thakur, Neeharika; Thompson, Barbara J.; Gong, Qian

2018-01-01

We present preliminary results obtained by observing the solar corona during the 2017 August 21 total solar eclipse using a polarization camera mounted on an eight-inch Schmidt-Cassegrain telescope. The observations were made from Madras Oregon during 17:19 to 17:21 UT. Total and polarized brightness images were obtained at four wavelengths (385, 398.5, 410, and 423 nm). The polarization camera had a polarization mask mounted on a 2048x2048 pixel CCD with a pixel size of 7.4 microns. The resulting images had a size of 975x975 pixels because four neighboring pixels were summed to yield the polarization and total brightness images. The ratio of 410 and 385 nm images is a measure of the coronal temperature, while that at 423 and 398.5 nm images is a measure of the coronal flow speed. We compared the temperature map from the eclipse observations with that obtained from the Solar Dynamics Observatory’s Atmospheric Imaging Assembly images at six EUV wavelengths, yielding consistent temperature information of the corona.

Metal stack optimization for low-power and high-density for N7-N5

NASA Astrophysics Data System (ADS)

Raghavan, P.; Firouzi, F.; Matti, L.; Debacker, P.; Baert, R.; Sherazi, S. M. Y.; Trivkovic, D.; Gerousis, V.; Dusa, M.; Ryckaert, J.; Tokei, Z.; Verkest, D.; McIntyre, G.; Ronse, K.

2016-03-01

One of the key challenges while scaling logic down to N7 and N5 is the requirement of self-aligned multiple patterning for the metal stack. This comes with a large cost of the backend cost and therefore a careful stack optimization is required. Various layers in the stack have different purposes and therefore their choice of pitch and number of layers is critical. Furthermore, when in ultra scaled dimensions of N7 or N5, the number of patterning options are also much larger ranging from multiple LE, EUV to SADP/SAQP. The right choice of these are also needed patterning techniques that use a full grating of wires like SADP/SAQP techniques introduce high level of metal dummies into the design. This implies a large capacitance penalty to the design therefore having large performance and power penalties. This is often mitigated with extra masking strategies. This paper discusses a holistic view of metal stack optimization from standard cell level all the way to routing and the corresponding trade-off that exist for this space.

Development of a 1m-normal-incidence-EUV-Telescope

NASA Technical Reports Server (NTRS)

Grewing, M.; Kraemer, G.; Schulz-Luepertz, E.; Wulf-Mathies, C.; Bowyer, S.; Jacobsen, P.; Jelinsky, P.; Kimble, R.

1982-01-01

A brief description is given of the 1m-EUV-Telescope and its focal plane instrumentation, namely an EUV spectrometer and six EUV/FUV photometers. The telescope is scheduled for launch on an Aries rocket on June 17, 1982. The principal goals are the white dwarf HZ43 and a photometric scan across the sky in an area of the sky where 21 cm line observations reveal a steep density gradient. The optical bench of the telescope is a cylinder made of a graphite epoxy compound. Despite its low specific weight, the bench shows an excellent mechanical performance, with an elasticity modulus of approximately 70,000 N/cu mm. It is pointed out that by carefully combining layers with different winding angles of the carbon fiber, the thermal expansion along the cylinder axis is almost negligible, even under severe thermal loads

The novel top-coat material for RLS trade-off reduction in EUVL

NASA Astrophysics Data System (ADS)

Onishi, Ryuji; Sakamoto, Rikimaru; Fujitani, Noriaki; Endo, Takafumi; Ho, Bang-ching

2012-03-01

For the next generation lithography (NGL), several technologies have been proposed to achieve the 22nm-node devices and beyond. Extreme ultraviolet (EUV) lithography is one of the candidates for the next generation lithography. In EUV light source development, low power is one of the critical issue because of the low throughput, and another issue is Out of Band (OoB) light existing in EUV light. OoB is concerned to be the cause of deterioration for the lithography performance. In order to avoid this critical issue, we focused on development of the resist top coat material with OoB absorption property as Out of Band Protection Layer (OBPL). We designed this material having high absorbance around 240nm wavelength and high transmittance for EUV light. And this material aimed to improve sensitivity, resolution and LWR performance.

Inter-Comparison between July 24, 2014 EUV Data from NASA Sounding Rocket 36.289 and Concurrent Measurements from Orbital Solar Observatories

NASA Astrophysics Data System (ADS)

Didkovsky, L. V.; Wieman, S. R.; Judge, D. L.

2014-12-01

Sounding rocket mission NASA 36.289 Didkovsky provided solar EUV irradiance measurements from four instruments built at the USC Space Sciences Center: the Rare Gas Ionization Cell (RGIC), the Solar Extreme ultraviolet Monitor (SEM), the Dual Grating Spectrometer (DGS), and the Optics-Free Spectrometer (OFS), thus meeting the mission comprehensive success criteria. These sounding rocket data allow us to inter-compare the observed absolute EUV irradiance with the data taken at the same time from the SOHO and SDO solar observatories. The sounding rocket data from the two degradation-free instruments (DGS and OFS) can be used to verify the degradation rates of SOHO and SDO EUV channels and serve as a flight-proven prototypes for future improvements of degradation-free instrumentation for solar physics.

Design of the Extreme Ultraviolet Explorer long-wavelength grazing incidence telescope optics

NASA Technical Reports Server (NTRS)

Finley, David S.; Jelinsky, Patrick; Bowyer, Stuart; Malina, Roger F.

1988-01-01

Designing optics for photometry in the long-wavelength portion of the EUV spectrum (400-900) A) poses different problems from those arising for optics, operating shortward of 400 A. The available filter materials which transmit radiation longward of 400 A are also highly transparent at wavelengths shortward of 100 A. Conventional EUV optics, with grazing engles of less than about 10 deg, have very high throughput in the EUV, which persists to wavelengths shortward of 100 A. Use of such optics with the longer-wavelength EUV filters thus results in an unacceptably large soft X-ray leak. This problem is overcome by developing a mirror design with larger graze angles of not less than 20 deg, which has high throughput at wavelengths longer than 400 A but at the same time very little throughput shortward of 100 A.

A New Relationship Between Soft X-Rays and EUV Flare Light Curves

NASA Astrophysics Data System (ADS)

Thiemann, Edward

2016-05-01

Solar flares are the result of magnetic reconnection in the solar corona which converts magnetic energy into kinetic energy resulting in the rapid heating of solar plasma. As this plasma cools, it emits radiation at different EUV wavelengths when the dropping temperature passes a line’s temperature of formation. This results in a delay in the emissions from cooler EUV lines relative to hotter EUV lines. Therefore, characterizing how this hot plasma cools is important for understanding how the corresponding geo-effective extreme ultraviolet (EUV) irradiance evolves in time. I present a simple new framework in which to study flare cooling by using a Lumped Element Thermal Model (LETM). LETM is frequently used in science and engineering to simplify a complex multi-dimensional thermal system by reducing it to a 0-D thermal circuit. For example, a structure that conducts heat out of a system is simplified with a resistive element and a structure that allows a system to store heat is simplified with a capacitive element. A major advantage of LETM is that the specific geometry of a system can be ignored, allowing for an intuitive analysis of the major thermal processes. I show that LETM is able to accurately reproduce the temporal evolution of cooler flare emission lines based on hotter emission line evolution. In particular, it can be used to predict the evolution of EUV flare light curves using the NOAA X-Ray Sensor (XRS).

Solar Cycle Variation of Microwave Polar Brightening and EUV Coronal Hole Observed by Nobeyama Radioheliograph and SDO/AIA

NASA Astrophysics Data System (ADS)

Kim, Sujin; Park, Jong-Yeop; Kim, Yeon-Han

2017-08-01

We investigate the solar cycle variation of microwave and extreme ultraviolet (EUV) intensity in latitude to compare microwave polar brightening (MPB) with the EUV polar coronal hole (CH). For this study, we used the full-sun images observed in 17 GHz of the Nobeyama Radioheliograph from 1992 July to 2016 November and in two EUV channels of the Atmospheric Imaging Assembly (AIA) 193 Å and 171 Å on the Solar Dynamics Observatory (SDO) from 2011 January to 2016 November. As a result, we found that the polar intensity in EUV is anti-correlated with the polar intensity in microwave. Since the depression of EUV intensity in the pole is mostly owing to the CH appearance and continuation there, the anti-correlation in the intensity implies the intimate association between the polar CH and the MPB. Considering the report of tet{gopal99} that the enhanced microwave brightness in the CH is seen above the enhanced photospheric magnetic field, we suggest that the pole area during the solar minimum has a stronger magnetic field than the quiet sun level and such a strong field in the pole results in the formation of the polar CH. The emission mechanism of the MPB and the physical link with the polar CH are not still fully understood. It is necessary to investigate the MPB using high resolution microwave imaging data, which can be obtained by the high performance large-array radio observatories such as the ALMA project.

Active galaxies observed during the Extreme Ultraviolet Explorer all-sky survey

NASA Technical Reports Server (NTRS)

Marshall, H. L.; Fruscione, A.; Carone, T. E.

1995-01-01

We present observations of active galactic nuclei (AGNs) obtained with the Extreme Ultraviolet Explorer (EUVE) during the all-sky survey. A total of 13 sources were detected at a significance of 2.5 sigma or better: seven Seyfert galaxies, five BL Lac objects, and one quasar. The fraction of BL Lac objects is higher in our sample than in hard X-ray surveys but is consistent with the soft X-ray Einstein Slew Survey, indicating that the main reason for the large number of BL Lac objects in the extreme ulktraviolet (EUV) and soft X-ray bands is their steeper X-ray spectra. We show that the number of AGNs observed in both the EUVE and ROSAT Wide Field Camera surveys can readily be explained by modelling the EUV spectra with a simple power law in the case of BL Lac objects and with an additional EUV excess in the case of Seyferts and quasars. Allowing for cold matter absorption in Seyfert galaxy hosts drive up the inferred average continuum slope to 2.0 +/- 0.5 (at 90% confidence), compared to a slope of 1.0 usually found from soft X-ray data. If Seyfert galaxies without EUV excesses form a significant fraction of the population, then the average spectrum of those with bumps should be even steeper. We place a conservative limit on neutral gas in BL Lac objects: N(sub H) less than 10(exp 20)/sq cm.

Absorption and emission of single attosecond light pulses in an autoionizing gaseous medium dressed by a time-delayed control field

NASA Astrophysics Data System (ADS)

Chu, Wei-Chun; Lin, C. D.

2013-01-01

An extreme ultraviolet (EUV) single attosecond pulse passing through a laser-dressed dense gas is studied theoretically. The weak EUV pulse pumps the helium gas from the ground state to the 2s2p(1P) autoionizing state, which is coupled to the 2s2(1S) autoionizing state by a femtosecond infrared laser with the intensity in the order of 1012 W/cm2. The simulation shows how the transient absorption and emission of the EUV are modified by the coupling laser. A simple analytical expression for the atomic response derived for δ-function pulses reveals the strong modification of the Fano lineshape in the spectra, where these features are quite universal and remain valid for realistic pulse conditions. We further account for the propagation of pulses in the medium and show that the EUV signal at the atomic resonance can be enhanced in the gaseous medium by more than 50% for specifically adjusted laser parameters, and that this enhancement persists as the EUV propagates in the gaseous medium. Our result demonstrates the high-level control of nonlinear optical effects that are achievable with attosecond pulses.

Design decisions from the history of the EUVE science payload

NASA Technical Reports Server (NTRS)

Marchant, W.

1993-01-01

Some of the design issues that arose during the development of the EUVE science payload and solutions to the problems involved are examined. In particular, attention is given to the use of parallel and serial busses, the selection of the the ROM approach for software storage and execution, implementation of memory error detection and correction, and the selection of command structures. The early design decisions paid off in the timely delivery of the scientific payload and in the successful completion of the survey phase of the EUVE science mission.

Design decisions from the history of the EUVE science payload

NASA Astrophysics Data System (ADS)

Marchant, W.

1993-09-01

Some of the design issues that arose during the development of the EUVE science payload and solutions to the problems involved are examined. In particular, attention is given to the use of parallel and serial busses, the selection of the the ROM approach for software storage and execution, implementation of memory error detection and correction, and the selection of command structures. The early design decisions paid off in the timely delivery of the scientific payload and in the successful completion of the survey phase of the EUVE science mission.

Change Detection in Uav Video Mosaics Combining a Feature Based Approach and Extended Image Differencing

NASA Astrophysics Data System (ADS)

Saur, Günter; Krüger, Wolfgang

2016-06-01

Change detection is an important task when using unmanned aerial vehicles (UAV) for video surveillance. We address changes of short time scale using observations in time distances of a few hours. Each observation (previous and current) is a short video sequence acquired by UAV in near-Nadir view. Relevant changes are, e.g., recently parked or moved vehicles. Examples for non-relevant changes are parallaxes caused by 3D structures of the scene, shadow and illumination changes, and compression or transmission artifacts. In this paper we present (1) a new feature based approach to change detection, (2) a combination with extended image differencing (Saur et al., 2014), and (3) the application to video sequences using temporal filtering. In the feature based approach, information about local image features, e.g., corners, is extracted in both images. The label "new object" is generated at image points, where features occur in the current image and no or weaker features are present in the previous image. The label "vanished object" corresponds to missing or weaker features in the current image and present features in the previous image. This leads to two "directed" change masks and differs from image differencing where only one "undirected" change mask is extracted which combines both label types to the single label "changed object". The combination of both algorithms is performed by merging the change masks of both approaches. A color mask showing the different contributions is used for visual inspection by a human image interpreter.

MAPPER: high-throughput maskless lithography

NASA Astrophysics Data System (ADS)

Wieland, M. J.; de Boer, G.; ten Berge, G. F.; Jager, R.; van de Peut, T.; Peijster, J. J. M.; Slot, E.; Steenbrink, S. W. H. K.; Teepen, T. F.; van Veen, A. H. V.; Kampherbeek, B. J.

2009-03-01

Maskless electron beam lithography, or electron beam direct write, has been around for a long time in the semiconductor industry and was pioneered from the mid-1960s onwards. This technique has been used for mask writing applications as well as device engineering and in some cases chip manufacturing. However because of its relatively low throughput compared to optical lithography, electron beam lithography has never been the mainstream lithography technology. To extend optical lithography double patterning, as a bridging technology, and EUV lithography are currently explored. Irrespective of the technical viability of both approaches, one thing seems clear. They will be expensive [1]. MAPPER Lithography is developing a maskless lithography technology based on massively-parallel electron-beam writing with high speed optical data transport for switching the electron beams. In this way optical columns can be made with a throughput of 10-20 wafers per hour. By clustering several of these columns together high throughputs can be realized in a small footprint. This enables a highly cost-competitive alternative to double patterning and EUV alternatives. In 2007 MAPPER obtained its Proof of Lithography milestone by exposing in its Demonstrator 45 nm half pitch structures with 110 electron beams in parallel, where all the beams where individually switched on and off [2]. In 2008 MAPPER has taken a next step in its development by building several tools. The objective of building these tools is to involve semiconductor companies to be able to verify tool performance in their own environment. To enable this, the tools will have a 300 mm wafer stage in addition to a 110-beam optics column. First exposures at 45 nm half pitch resolution have been performed and analyzed. On the same wafer it is observed that all beams print and based on analysis of 11 beams the CD for the different patterns is within 2.2 nm from target and the CD uniformity for the different patterns is better than 2.8 nm.

Debris- and radiation-induced damage effects on EUV nanolithography source collector mirror optics performance

NASA Astrophysics Data System (ADS)

Allain, J. P.; Nieto, M.; Hendricks, M.; Harilal, S. S.; Hassanein, A.

2007-05-01

Exposure of collector mirrors facing the hot, dense pinch plasma in plasma-based EUV light sources to debris (fast ions, neutrals, off-band radiation, droplets) remains one of the highest critical issues of source component lifetime and commercial feasibility of nanolithography at 13.5-nm. Typical radiators used at 13.5-nm include Xe and Sn. Fast particles emerging from the pinch region of the lamp are known to induce serious damage to nearby collector mirrors. Candidate collector configurations include either multi-layer mirrors (MLM) or single-layer mirrors (SLM) used at grazing incidence. Studies at Argonne have focused on understanding the underlying mechanisms that hinder collector mirror performance at 13.5-nm under fast Sn or Xe exposure. This is possible by a new state-of-the-art in-situ EUV reflectometry system that measures real time relative EUV reflectivity (15-degree incidence and 13.5-nm) variation during fast particle exposure. Intense EUV light and off-band radiation is also known to contribute to mirror damage. For example offband radiation can couple to the mirror and induce heating affecting the mirror's surface properties. In addition, intense EUV light can partially photo-ionize background gas (e.g., Ar or He) used for mitigation in the source device. This can lead to local weakly ionized plasma creating a sheath and accelerating charged gas particles to the mirror surface and inducing sputtering. In this paper we study several aspects of debris and radiation-induced damage to candidate EUVL source collector optics materials. The first study concerns the use of IMD simulations to study the effect of surface roughness on EUV reflectivity. The second studies the effect of fast particles on MLM reflectivity at 13.5-nm. And lastly the third studies the effect of multiple energetic sources with thermal Sn on 13.5-nm reflectivity. These studies focus on conditions that simulate the EUVL source environment in a controlled way.

Solar EUV Irradiance Measurements by the Auto-Calibrating EUV Spectrometers (SolACES) Aboard the International Space Station (ISS)

NASA Astrophysics Data System (ADS)

Schmidtke, G.; Nikutowski, B.; Jacobi, C.; Brunner, R.; Erhardt, C.; Knecht, S.; Scherle, J.; Schlagenhauf, J.

2014-05-01

SolACES is part of the ESA SOLAR ISS mission that started aboard the shuttle mission STS-122 on 7 February 2008. The instrument has recorded solar extreme ultraviolet (EUV) irradiance from 16 to 150 nm during the extended solar activity minimum and the beginning solar cycle 24 with rising solar activity and increasingly changing spectral composition. The SOLAR mission has been extended from a period of 18 months to > 8 years until the end of 2016. SolACES is operating three grazing incidence planar grating spectrometers and two three-current ionization chambers. The latter ones are considered as primary radiometric detector standards. Re-filling the ionization chambers with three different gases repeatedly and using overlapping band-pass filters, the absolute EUV fluxes are derived in these spectral intervals. This way the serious problem of continuing efficiency changes in space-borne instrumentation is overcome during the mission. Evaluating the three currents of the ionization chambers, the overlapping spectral ranges of the spectrometers and of the filters plus inter-comparing the results from the EUV photon absorption in the gases with different absorption cross sections, there are manifold instrumental possibilities to cross-check the results providing a high degree of reliability to the spectral irradiance derived. During the mission a very strong up-and-down variability of the spectrometric efficiency by orders of magnitude is observed. One of the effects involved is channeltron degradation. However, there are still open questions on other effects contributing to these changes. A survey of the measurements carried out and first results of the solar spectral irradiance (SSI) data are presented. Inter-comparison with EUV data from other space missions shows good agreement such that the international effort has started to elaborate a complete set of EUV-SSI data taking into account all data available from 2008 to 2013.

Effect of the Solar UV/EUV Heating on the Intensity and Spatial Distribution of Jupiter's Synchrotron Radiation

NASA Astrophysics Data System (ADS)

Kita, Hajime; Misawa, H.; Tsuchiya, F.; Tao, C.; Morioka, A.

2012-10-01

Jupiter's synchrotron radiation (JSR) is the emission from relativistic electrons, and it is the most effective probe for remote sensing of Jupiter's radiation belt from the Earth. Recent observations reveal short term variations of JSR with the time scale of days to weeks. Brice and McDonough (1973) proposed that the solar UV/EUV heating for Jupiter's upper atmosphere causes enhancement of total flux density. If such a process occurs at Jupiter, it is also expected that diurnal wind system produces dawn-dusk asymmetry of the JSR brightness distribution. Preceding studies confirmed that the short term variations in total flux density correspond to the solar UV/EUV. However, the effect of solar UV/EUV heating on the brightness distribution has not been confirmed. Hence, the purpose of this study is to confirm the solar UV/EUV heating effect on total flux density and brightness distribution. We made radio imaging analysis using the National Radio Astronomy Observatory (NRAO) archived data of the Very Large Array (VLA) obtained in 2000, and following results were shown. 1, Total flux density varied corresponding to the solar UV/EUV. 2, Dawn side emission was brighter than dusk side emission almost every day. 3, Variations of the dawn-dusk asymmetry did not correspond to the solar UV/EUV. In order to explain the second result, we estimate the diurnal wind velocity from the observed dawn-dusk ratio by using the model brightness distribution of JSR. Estimated neutral wind velocity is 46+/-11 m/s, which reasonably corresponds to the numerical simulation of Jupiter's upper atmosphere. In order to explain the third result, we examined the effect of the global convection electric field driven by tailward outflow of plasma in Jupiter's magnetosphere. As the result, it is suggested that typical fluctuation of the convection electric field strength was enough to cause the observed variations of the dawn-dusk asymmetry.

Recent status of resist outgas testing for metal containing resists at EIDEC

NASA Astrophysics Data System (ADS)

Shiobara, Eishi; Mikami, Shinji; Yamada, Kenji

2018-03-01

The metal containing resist is one of the strong candidates for high lithographic performance Extreme Ultraviolet (EUV) resists. EIDEC has prepared the infrastructure for outgas testing in hydrogen environment for metal containing resists at High Power EUV irradiation tool (HPEUV). We have experimentally obtained the preliminary results of the non-cleanable metal contamination on witness sample using model material by HPEUV [1]. The metal contamination was observed at only the condition of hydrogen environment. It suggested the generation of volatile metal hydrides by hydrogen radicals. Additionally, the metal contamination on a witness sample covered with Ru was not removed by hydrogen radical cleaning. The strong interaction between the metal hydride and Ru was confirmed by the absorption simulation [2]. Recently, ASML announced a resist outgassing barrier technology using Dynamic Gas Lock (DGL) membrane located between projection optics and wafer stage [3, 4]. DGL membrane blocks the diffusion of all kinds of resist outgassing to the projection optics and prevents the reflectivity loss of EUV mirrors. The investigation of DGL membrane for high volume manufacturing is just going on. It extends the limitation of material design for EUV resists. However, the DGL membrane has an impact for the productivity of EUV scanners due to the transmission loss of EUV light and the necessity of periodic maintenance. The well understanding and control of the outgassing characteristics of metal containing resists may help to improve the productivity of EUV scanner. We consider the outgas evaluation for the resists still useful. For the improvement of resist outgas testing in hydrogen, there are some issues such as the contamination limited regime, the optimization of exposure dose to obtain the measurable contamination film thickness and the detection of minimum amount of metal related outgas species generated. We are considering a new platform of outgas testing for metal containing resists based on the electron-beam irradiation system as one of the solutions for these issues. The concept is presented in this paper.

Simultaneous ASCA and EUVE Observations of Capella

NASA Astrophysics Data System (ADS)

Brickhouse, N. S.; Dupree, A. K.; Edgar, R. J.; Drake, S. A.; White, N. E.; Liedahl, D. A.; Singh, K. P.

1997-05-01

We present simultaneous observations taken in Mar 1996 of the bright stellar coronal source Capella (HD 34029) with the ASCA and EUVE satellites. Previous EUVE observations of Fe emission lines (Fe VIII --- XXIV, excluding XVII) revealed a narrow emission measure feature at 6 x 10(6) K, which has proven to be remarkably stable over several years (flux from Fe XVIII and XIX has not varied by more than 30%), while lines formed at higher temperatures have shown intensity variations up to factors of 4. Furthermore, extremely high signal-to-noise spectra obtained by summing all EUVE measurements show that the Fe/H abundance ratio is consistent with solar photospheric. (See Dupree et al. 1993, ApJ, 418, L41; Brickhouse, Raymond, & Smith 1995, ApJSupp, 97, 551; Brickhouse 1996, IAU Coll. 152, Astrophysics in the Extreme Ultraviolet, Bowyer & Malina, eds (Kluwer), 141.) Meanwhile, the ASCA data of Capella have proven notoriously difficult to analyze. The performance verification (PV) phase data suggested a somewhat subsolar Fe abundance, but models were in poor agreement with the data (chi (2red) ~ 6). (See Drake 1996, Conf. on Cosmic Abundances, U. Maryland). Since the emission lines observed by EUVE are formed at the same emitting temperatures as the X-ray spectrum (Capella is ``soft'' such that very little flux is observed above 2 keV), the emission measure distribution derived from EUVE lines should provide a direct prediction of the X-ray spectrum, with only the relative abundances of species other than Fe as free parameters. Like the PV data, the new ASCA spectrum is not well fit by any of the standard models. Applying the constraints imposed by EUVE does not make a major improvement in the fit --- multi-thermal, variable abundance models such as Raymond-Smith and MEKAL do not provide any acceptable fit (chi (2red) > 5). We discuss our efforts to understand the X-ray spectrum, including studies of the uncertainties in the atomic data and of the underlying assumptions of the source models.

Designing a Small-Sized Engineering Model of Solar EUV Telescopr for a Korean Satellite

NASA Astrophysics Data System (ADS)

Han, Jung-Hoon; Jang, Min-Hwan; Kim, Sang-Joon

2001-11-01

For the research of solar EUV (extreme ultraviolet) radiation, we have designed a small-sized engineering model of solar EUV telescope, which is suitable for a Korean satellite. The EUV solar telescope was designed to observe the sun at 584.3Å (He¥°) and 629.7Å (O¥´). The optical system is an f/8 Ritchey-Chrètien, and the effective diameter and focal length are 80§® and 640§®, respectively. The He¥°and O¥´ filters are loaded in a filter wheel. In the detection part, the MCP (MicroChannel Plate) type is Z-stack, and the channel-to-diameter ratio is 40:1. MCP and CCD are connected by fiber optic taper. A commercial optical design software is used for the analysis of the optical system design.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Laser-induced extreme UV radiation sources for manufacturing next-generation integrated circuits

NASA Astrophysics Data System (ADS)

Borisov, V. M.; Vinokhodov, A. Yu; Ivanov, A. S.; Kiryukhin, Yu B.; Mishchenko, V. A.; Prokof'ev, A. V.; Khristoforov, O. B.

2009-10-01

The development of high-power discharge sources emitting in the 13.5±0.135-nm spectral band is of current interest because they are promising for applications in industrial EUV (extreme ultraviolet) lithography for manufacturing integrated circuits according to technological precision standards of 22 nm and smaller. The parameters of EUV sources based on a laser-induced discharge in tin vapours between rotating disc electrodes are investigated. The properties of the discharge initiation by laser radiation at different wavelengths are established and the laser pulse parameters providing the maximum energy characteristics of the EUV source are determined. The EUV source developed in the study emits an average power of 276 W in the 13.5±0.135-nm spectral band on conversion to the solid angle 2π sr in the stationary regime at a pulse repetition rate of 3000 Hz.

Double exposure technique for 45nm node and beyond

NASA Astrophysics Data System (ADS)

Hsu, Stephen; Park, Jungchul; Van Den Broeke, Douglas; Chen, J. Fung

2005-11-01

The technical challenges in using F2 lithography for the 45nm node, along with the insurmountable difficulties in EUV lithography, has driven the semiconductor chipmaker into the low k1 lithography era under the pressure of ever decreasing feature sizes. Extending lithography towards lower k1 puts heavy demand on the resolution enhancement technique (RET), exposure tool, and the need for litho friendly design. Hyper numerical aperture (NA) exposure tools, immersion, and double exposure techniques (DET's) are the promising methods to extend lithography manufacturing to the 45nm node at k1 factors below 0.3. Scattering bars (SB's) have become an integral part of the lithography process as chipmakers move to production at ever lower k1 factors. To achieve better critical dimension (CD) control, polarization is applied to enhance the image contrast in the preferential imaging orientation, which increases the risk of SB printability. The optimum SB width is approximately (0.20 ~ 0.25)*(λ/NA). When the SB width becomes less than the exposure wavelength on the 4X mask, Kirchhoff's scalar theory under predicts the SB intensity. The optical weighting factor of the SB increases (Figure 1b) and the SB's become more susceptible to printing. Meanwhile, under hyper NA conditions, the effectiveness of "subresolution" SB's is significantly diminished. A full-sized scattering bars (FSB) scheme becomes necessary. Double exposure methods, such as using ternary 6% attenuated PSM (attPSM) for DDL, are good imaging solutions that can reach and likely go beyond the 45nm node. Today DDL, using binary chrome masks, is capable of printing 65 nm device patterns. In this work, we investigate the use of DET with 6% attPSM masks to target 45nm node device. The SB scalability and printability issues can be taken cared of by using "mutual trimming", i.e., with the combined energy from the two exposures. In this study, we share our findings of using DET to pattern a 45nm node device design with polarization and immersion. We also explore other double patterning methods which in addition to having two exposures, incorporates double coat/developing/etch processing to break the 0.25 k1 barrier.

Marching of the microlithography horses: electron, ion, and photon: past, present, and future

NASA Astrophysics Data System (ADS)

Lin, Burn J.

2007-03-01

Microlithography patterning employs one of three media; electron, ion, and photon. They are in a way like horses, racing towards the mainstream. Some horses such as electrons run fast but repel each other. Ion beams behave like electron beams but are less developed. The photon beam is the undisputed workhorse, taking microlithography from the 5-μm minimum feature size to 32-nm half pitch. This paper examines the history of microlithography in pattern generation, proximity printing, and projection printing, then identifies the strong and weak points of each technology. In addition to ion-beam and e-beam lithography, the coverage of optical lithography spans the wavelength from 436 to 13.5 nm. Our learning from history helps us prevent mistakes in the future. In almost all cases, making or using the mask presents one of the limiting problems, no matter the type of beams or the replication method. Only the maskless method relieves us from mask-related problems. A way to overcome the low throughput handicap of maskless systems is to use multiple e-beam direct writing, whose imaging lens can be economically and compactly fabricated using MEMS techniques. In a way, the history of microlithography parallels that of aviation. Proximity printing is like the Wright-Brothers' plane; 1X projection printing, single-engine propeller plane with unitized body; reduction step-and-repeat projection printing, multi-engine commercial airliner; scanners, jet airliners. Optical lithography has improved in many ways than just increasing NA and reducing wavelength just as the commercial airliners improving in many other areas than just the speed. The SST increased the speed of airliners by more than a factor of two just as optical resolution doubled with double exposures. EUV lithography with the wavelength reduced by an order of magnitude is similar to the space shuttle increasing its speed to more than 10 times that of the SST. Multiple-beam direct write systems are like helicopters. They do not need airports(masks) but we need a lot of beams to carry the same payload.

Reconstruction of Solar Extreme Ultraviolet Flux 1740 - 2015

NASA Astrophysics Data System (ADS)

Svalgaard, Leif

2016-11-01

Solar extreme ultraviolet (EUV) radiation creates the conducting E-layer of the ionosphere, mainly by photo-ionization of molecular oxygen. Solar heating of the ionosphere creates thermal winds, which by dynamo action induce an electric field driving an electric current having a magnetic effect observable on the ground, as was discovered by G. Graham in 1722. The current rises and falls with the Sun, and thus causes a readily observable diurnal variation of the geomagnetic field, allowing us to deduce the conductivity and thus the EUV flux as far back as reliable magnetic data reach. High-quality data go back to the "Magnetic Crusade" of the 1830s and less reliable, but still usable, data are available for portions of the 100 years before that. J.R. Wolf and, independently, J.-A. Gautier discovered the dependence of the diurnal variation on solar activity, and today we understand and can invert that relationship to construct a reliable record of the EUV flux from the geomagnetic record. We compare that to the F_{10.7} flux and the sunspot number, and we find that the reconstructed EUV flux reproduces the F_{10.7} flux with great accuracy. On the other hand, it appears that the Relative Sunspot Number as currently defined is beginning to no longer be a faithful representation of solar magnetic activity, at least as measured by the EUV and related indices. The reconstruction suggests that the EUV flux reaches the same low (but non-zero) value at every sunspot minimum (possibly including Grand Minima), representing an invariant "solar magnetic ground state".

Overlying extreme-ultraviolet arcades preventing eruption of a filament observed by AIA/SDO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Huadong; Ma, Suli; Zhang, Jun, E-mail: hdchen@upc.edu.cn

2013-11-20

Using the multi-wavelength data from the Atmospheric Imaging Assembly/Solar Dynamic Observatory (AIA/SDO) and the Sun Earth Connection Coronal and Heliospheric Investigation/Solar Terrestrial Relations Observatory (SECCHI/STEREO), we report a failed filament eruption in NOAA AR 11339 on 2011 November 3. The eruption was associated with an X1.9 flare, but without any coronal mass ejection (CME), coronal dimming, or extreme ultraviolet (EUV) waves. Some magnetic arcades above the filament were observed distinctly in EUV channels, especially in the AIA 94 Å and 131 Å wavebands, before and during the filament eruption process. Our results show that the overlying arcades expanded along withmore » the ascent of the filament at first until they reached a projected height of about 49 Mm above the Sun's surface, where they stopped. The following filament material was observed to be confined by the stopped EUV arcades and not to escape from the Sun. After the flare, a new filament formed at the low corona where part of the former filament remained before its eruption. These results support that the overlying arcades play an important role in preventing the filament from successfully erupting outward. We also discuss in this paper the EUV emission of the overlying arcades during the flare. It is rare for a failed filament eruption to be associated with an X1.9 class flare, but not with a CME or EUV waves. Therefore, this study also provides valuable insight into the triggering mechanism of the initiation of CMEs and EUV waves.« less

Quasi-periodic Fast-mode Wave Trains Within a Global EUV Wave and Sequential Transverse Oscillations Detected by SDO-AIA

NASA Technical Reports Server (NTRS)

Liu, Wei; Ofman, Leon; Nitta, Nariaki; Aschwanden, Markus J.; Schrijver, Carolus J.; Title, Alan M.; Tarbell, Theodore D.

2012-01-01

We present the first unambiguous detection of quasi-periodic wave trains within the broad pulse of a global EUV wave (so-called EIT wave) occurring on the limb. These wave trains, running ahead of the lateral coronal mass ejection (CME) front of 2-4 times slower, coherently travel to distances greater than approximately solar radius/2 along the solar surface, with initial velocities up to 1400 kilometers per second decelerating to approximately 650 kilometers per second. The rapid expansion of the CME initiated at an elevated height of 110 Mm produces a strong downward and lateral compression, which may play an important role in driving the primary EUV wave and shaping its front forwardly inclined toward the solar surface. The wave trains have a dominant 2 minute periodicity that matches the X-ray flare pulsations, suggesting a causal connection. The arrival of the leading EUV wave front at increasing distances produces an uninterrupted chain sequence of deflections and/or transverse (likely fast kink mode) oscillations of local structures, including a flux-rope coronal cavity and its embedded filament with delayed onsets consistent with the wave travel time at an elevated (by approximately 50%) velocity within it. This suggests that the EUV wave penetrates through a topological separatrix surface into the cavity, unexpected from CME-caused magnetic reconfiguration. These observations, when taken together, provide compelling evidence of the fast-mode MHD wave nature of the primary (outer) fast component of a global EUV wave, running ahead of the secondary (inner) slow component of CME-caused restructuring.

Hot interstellar gas and ionization of embedded clouds

NASA Technical Reports Server (NTRS)

Cheng, K.-P.; Bruhweiler, F.

1990-01-01

Researchers present detailed photoionization calculations for the instellar cloud in which the Sun is embedded. They consider the EUV radiation field with contribution from discrete stellar sources and from a thermal bremsstrahlung-radiative recombination spectrum emitted from the surrounding 10 to the 6th power k coronal substrate. They establish lower limits to the fractional ionization of hydrogen and helium of 0.17 and 0.29 respectively. The high He ionization fraction results primarily from very strong line emission below 500 A originating in the surrounding coronal substrate while the H ionization is dominated by the EUV radiation from the discrete stellar sources. The dual effects of thermal conduction and the EUV spectrum of the 10 to the 6th k plasma on ionization in the cloud skin are explored. The EUV radiation field and Auger ionization have insignificant effects on the resulting ionic column densities of Si IV, C IV, N V and O VI through the cloud skin. Calculations show that the abundances of these species are dominated by collisional ionization in the thermal conduction front. Because of a low charge exchange rate with hydrogen, the ionic column density ratios of N (CIII)/N (CII) and N (NII)/N (NI) are dominated by the EUV radiation field in the local interstellar medium. These ratios should be important diagnostics for the EUV radiation field and serve as surrogate indicators of the interstellar He and H ionization fraction respectively. Spacecraft such as Lyman which is designed to obtain high resolution spectral data down to the Lyman limit at 912 A could sample interstellar lines of these ions.

Toward compact and ultra-intense laser driven soft x-ray lasers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sebban, Stéphane

2017-05-01

We report here recent work on an optical-field ionized (OFI), high-order harmonic-seeded EUV laser. The amplifying medium is a plasma of nickel-like krypton obtained by optical field ionization focusing a 1 J, 30 fs, circularly- polarized, infrared pulse into a krypton-filled gas cell or krypton gas jet. The lasing transition is the 3d94p (J=0) --> 3d94p (J=1) transition of Ni-like krypton ions at 32.8 nm and is pumped by collisions with hot electrons. The polarization of the HH-seeded EUV laser beam was studied using an analyzer composed of three grazing incidence EUV multilayer mirrors able to spin under vacuum. For linear polarization, the Malus law has been recovered while in the case of a circularly-polarized seed, the EUV signal is insensitive to the rotation of the analyzer, bearing testimony to circularly polarized. The gain dynamics was probed by seeding the amplifier with a high-order harmonic pulse at different delays. The gain duration monotonically decreased from 7 ps to an unprecedented shortness of 450 fs FWHM as the amplification peak rose from 150 to 1,200 with an increase of the plasma density from 3 × 1018 cm-3 up to 1.2 × 1020 cm-3. The integrated energy of the EUV laser pulse was also measured, and found to be around 2 μJ. It is to be noted that in the ASE mode, longer amplifiers were achieved (up to 3 cm), yielding EUV outputs up to 14 μJ.

Sensitivity enhancement of chemically amplified resists and performance study using EUV interference lithography

NASA Astrophysics Data System (ADS)

Buitrago, Elizabeth; Nagahara, Seiji; Yildirim, Oktay; Nakagawa, Hisashi; Tagawa, Seiichi; Meeuwissen, Marieke; Nagai, Tomoki; Naruoka, Takehiko; Verspaget, Coen; Hoefnagels, Rik; Rispens, Gijsbert; Shiraishi, Gosuke; Terashita, Yuichi; Minekawa, Yukie; Yoshihara, Kosuke; Oshima, Akihiro; Vockenhuber, Michaela; Ekinci, Yasin

2016-03-01

Extreme ultraviolet lithography (EUVL, λ = 13.5 nm) is the most promising candidate to manufacture electronic devices for future technology nodes in the semiconductor industry. Nonetheless, EUVL still faces many technological challenges as it moves toward high-volume manufacturing (HVM). A key bottleneck from the tool design and performance point of view has been the development of an efficient, high power EUV light source for high throughput production. Consequently, there has been extensive research on different methodologies to enhance EUV resist sensitivity. Resist performance is measured in terms of its ultimate printing resolution, line width roughness (LWR), sensitivity (S or best energy BE) and exposure latitude (EL). However, there are well-known fundamental trade-off relationships (LRS trade-off) among these parameters for chemically amplified resists (CARs). Here we present early proof-of-principle results for a multi-exposure lithography process that has the potential for high sensitivity enhancement without compromising other important performance characteristics by the use of a Photosensitized Chemically Amplified Resist (PSCAR). With this method, we seek to increase the sensitivity by combining a first EUV pattern exposure with a second UV flood exposure (λ = 365 nm) and the use of a PSCAR. In addition, we have evaluated over 50 different state-of-the-art EUV CARs. Among these, we have identified several promising candidates that simultaneously meet sensitivity, LWR and EL high performance requirements with the aim of resolving line space (L/S) features for the 7 and 5 nm logic node (16 nm and 13 nm half-pitch HP, respectively) for HVM. Several CARs were additionally found to be well resolved down to 12 nm and 11 nm HP with minimal pattern collapse and bridging, a remarkable feat for CARs. Finally, the performance of two negative tone state-of-the-art alternative resist platforms previously investigated was compared to the CAR performance at and below 16 nm HP resolution, demonstrating the need for alternative resist solutions at 13 nm resolution and below. EUV interference lithography (IL) has provided and continues to provide a simple yet powerful platform for academic and industrial research enabling the characterization and development of new resist materials before commercial EUV exposure tools become available. Our experiments have been performed at the EUV-IL set-up in the Swiss Light Source (SLS) synchrotron facility located at the Paul Scherrer Institute (PSI).

High-speed atomic force microscopy and peak force tapping control

NASA Astrophysics Data System (ADS)

Hu, Shuiqing; Mininni, Lars; Hu, Yan; Erina, Natalia; Kindt, Johannes; Su, Chanmin

2012-03-01

ITRS Roadmap requires defect size measurement below 10 nanometers and challenging classifications for both blank and patterned wafers and masks. Atomic force microscope (AFM) is capable of providing metrology measurement in 3D at sub-nanometer accuracy but has long suffered from drawbacks in throughput and limitation of slow topography imaging without chemical information. This presentation focus on two disruptive technology developments, namely high speed AFM and quantitative nanomechanical mapping, which enables high throughput measurement with capability of identifying components through concurrent physical property imaging. The high speed AFM technology has allowed the imaging speed increase by 10-100 times without loss of the data quality. Such improvement enables the speed of defect review on a wafer to increase from a few defects per hour to nearly 100 defects an hour, approaching the requirements of ITRS Roadmap. Another technology development, Peak Force Tapping, substantially simplified the close loop system response, leading to self-optimization of most challenging samples groups to generate expert quality data. More importantly, AFM also simultaneously provides a series of mechanical property maps with a nanometer spatial resolution during defect review. These nanomechanical maps (including elastic modulus, hardness, and surface adhesion) provide complementary information for elemental analysis, differentiate defect materials by their physical properties, and assist defect classification beyond topographic measurements. This paper will explain the key enabling technologies, namely high speed tip-scanning AFM using innovative flexure design and control algorithm. Another critical element is AFM control using Peak Force Tapping, in which the instantaneous tip-sample interaction force is measured and used to derive a full suite of physical properties at each imaging pixel. We will provide examples of defect review data on different wafers and media disks. The similar AFM-based defect review capacity was also applied to EUV masks.