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Sample records for modeling euvl mask

  1. A practical approach for modeling EUVL mask defects

    SciTech Connect

    Gullikson, E.M.; Cerjan, C.; Stearns, D.J.; Mirkarimi, P.B.; Sweeney, D.W.

    2001-06-01

    An approximate method is proposed to calculate the EUV scattering from a defect within a multilayer coating. In this single surface approximation (SSA) the defective multilayer structure is replaced by a single reflecting surface with the shape of the top surface of the multilayer. The range of validity of this approximation has been investigated for Gaussian line defects using 2D finite-difference-time-domain simulations. The SSA is found to be valid for sufficiently low aspect ratio defects such as those expected for the critical defects nucleated by particles on the mask substrate. The critical EUVL defect size is calculated by combining the SSA with a multilayer growth model and aerial image simulations. Another approximate method for calculating the aerial image of an unresolved defect is also discussed. Although the critical substrate defects may be larger than the resolution of higher NA cameras, the point defect approximation provides a useful framework for understanding the printability of a wide range of defects.

  2. EUVL alternating phase shift mask

    NASA Astrophysics Data System (ADS)

    Yan, Pei-Yang; Myers, Alan; Shroff, Yashesh; Chandhok, Manish; Zhang, Guojing; Gullikson, Eric; Salmassi, Farhad

    2011-04-01

    Extreme ultra-violet Lithography (EUVL) alternating phase shift mask (APSM) or other optical enhancement techniques are likely needed for 16nm (half pitch) technology generation and beyond. One possible option is the combination of EUVL and APSM. The fabrication of EUVL APSM is more difficult than either the fabrication of an EUVL binary mask or a conventional optical APSM mask. In the case of EUVL APSM, the phase difference in the two regions (0 and 180-degree phase regions) is created by a phase step in the substrate prior to the multilayer (ML) coating. The step height that induces 180-degree phase mismatch in the ML is determined by [λ/(4cosθ)](2m+1), where m are integers (0, 1, 2,...). In this experiment, we targeted for a step height with m=1. The same mask design also contains the standard binary structures so that the comparison between the EUVL APSM and the EUVL binary mask can be performed under the same illumination and wafer process conditions. The EUVL APSM mask was exposed using Nikon's EUV1 scanner in Kumagaya Japan. The wafer level results showed higher dense line resolution for EUVL APSM as compared to that of EUVL binary mask. APSM also showed improved line width roughness (LWR) and depth of focus (DoF) as compared to the best EUVL binary results obtained with C-dipole off-axis illumination (OAI). The wafer CD resolution improvement obtained by APSM in this experiment is partially limited by the resist resolution and the mask phase edge spread during ML deposition. We believe that wafer CD resolution and can further be improved with imaging imbalance compensation mask design and improvements in resist resolution and the phase generation portion of the mask fabrication process. In this paper, we will discuss in detail the mask fabrication process, wafer level data analysis, and our understanding of EUVL APSM related issues.

  3. EUVL Mask Blank Repair

    SciTech Connect

    Barty, A; Mirkarimi, P; Stearns, D G; Sweeney, D; Chapman, H N; Clift, M; Hector, S; Yi, M

    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 variations 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.

  4. SEMATECH EUVL mask program status

    NASA Astrophysics Data System (ADS)

    Yun, Henry; Goodwin, Frank; Huh, Sungmin; Orvek, Kevin; Cha, Brian; Rastegar, Abbas; Kearney, Patrick

    2009-04-01

    As we approach the 22nm half-pitch (hp) technology node, the industry is rapidly running out of patterning options. Of the several lithography techniques highlighted in the International Technology Roadmap for Semiconductors (ITRS), the leading contender for the 22nm hp insertion is extreme ultraviolet lithography (EUVL). Despite recent advances with EUV resist and improvements in source power, achieving defect free EUV mask blank and enabling the EUV mask infrastructure still remain critical issues. To meet the desired EUV high volume manufacturing (HVM) insertion target date of 2013, these obstacles must be resolved on a timely bases. Many of the EUV mask related challenges remain in the pre-competitive stage and a collaborative industry based consortia, such as SEMATECH can play an important role to enable the EUVL landscape. SEMATECH based in Albany, NY is an international consortium representing several of the largest manufacturers in the semiconductor market. Full members include Intel, Samsung, AMD, IBM, Panasonic, HP, TI, UMC, CNSE (College of Nanoscience and Engineering), and Fuller Road Management. Within the SEMATECH lithography division a major thrust is centered on enabling the EUVL ecosystem from mask development, EUV resist development and addressing EUV manufacturability concerns. An important area of focus for the SEMATECH mask program has been the Mask Blank Development Center (MBDC). At the MBDC key issues in EUV blank development such as defect reduction and inspection capabilities are actively pursued together with research partners, key suppliers and member companies. In addition the mask program continues a successful track record of working with the mask community to manage and fund critical mask tools programs. This paper will highlight recent status of mask projects and longer term strategic direction at the MBDC. It is important that mask technology be ready to support pilot line development HVM by 2013. In several areas progress has been

  5. EUVL mask substrate specifications (wafer-type)

    SciTech Connect

    Tong, W

    1999-07-01

    The Extreme Ultraviolet Lithography (EUVL) program currently is constructing an alpha-class exposure tool known as the Engineering Test Stand (ETS) that will employ 200mm wafer format masks. This report lists and explains the current specifications for the EUVL mask substrates suitable for use on the ETS. The shape and size of the mask are the same as those of a standard 200mm Si wafer. The flatness requirements are driven by the potential image placement distortion caused by the non-telecentric illumination of EUVL. The defect requirements are driven by the printable-defect size and desired yield for mask blank fabrication. Surface roughness can cause both a loss of light throughput and image speckle. The EUVL mask substrate must be made of low-thermal-expansion material because 40% of the light is absorbed by the multilayers and causes some uncorrectable thermal distortion during printing.

  6. 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

  7. EUVL mask manufacturing: technologies and results

    NASA Astrophysics Data System (ADS)

    Letzkus, Florian; Butschke, Joerg; Irmscher, Mathias; Sailer, Holger; Dersch, Uwe; Holfeld, Christian

    2005-11-01

    Extreme Ultraviolet Lithography (EUVL) is the favourite next generation lithography candidate for IC device manufacturing with feature sizes beyond 32nm. Different stacks and manufacturing concepts have been published for the fabrication of the reflective EUVL masks. Patterning processes for two different absorber-buffer combinations on top of the reflective multi layer mirror have been developed. A TaN/SiO2 absorber-buffer stack was provided by supplier A and TaBN/Cr by supplier B. In addition both absorbers were covered by an anti reflective coating (ARC) layer. An e-beam patterned 300nm thick film of Fuji FEP171 was used as resist mask. We optimized the etching processes for maximum selectivities between absorber, buffer and capping layers on the one hand and rectangular profiles and low etch bias on the other hand. While both TaN based absorbers have been dry etched in an UNAXIS mask etcher III, wet and dry etch steps have been evaluated for the two different buffer layers. The minimum feature size of lines and holes in our test designs was 100nm. After freezing the processes a proximity correction was determined considering both, the influence of electron scattering due to e-beam exposure and the influence of the patterning steps. Due to the correction an outstanding linearity and iso/dense bias on different test designs was achieved. Various masks for printing experiments at the small-field Micro Exposure Tool (MET) in Berkeley and the fabrication of the ASML α-tool setup mask within the European MEDEA+ EXTUMASK project were done using the developed processes. Finally, we will compare and discuss the results of the two stack approaches.

  8. EUVL mask inspection at Hydrogen Lyman Alpha

    NASA Astrophysics Data System (ADS)

    Jota, Thiago S.; Milster, Tom D.

    2012-11-01

    Mask inspection is an outstanding challenge for Extreme Ultra-Violet Lithography (EUVL). The purpose of this investigation is to compare imaging characteristics of ArF and KrF inspection sources to imaging characteristics using a source at the Lyman-alpha line of Hydrogen at 121.6nm (HLA). HLA provides a raw resolution improvement of 37% to ArF and 51% to KrF, based on proportional wavelength scaling. The HLA wavelength is in an atmospheric transmission window, so a vacuum environment is not required. Our comparison uses rigorous vector imaging techniques to simulate partially coherent illumination schemes and reasonably accurate mask material properties and dimensions. Contrast is evaluated for representative spatial frequencies. Imaging and detection of defects are also considered with NILS and MEEF. The goal is high throughput inspection with maximum resolution, contrast, and sensitivity.

  9. Mask substrate requirements and development for extreme ultraviolet lithography (EUVL)

    SciTech Connect

    Hector, S D; Shell, M; Taylor, J S; Tong, W M

    1999-09-28

    The mask is deemed one of the areas that require significant research and development in EUVL. Silicon wafers will be used for mask substrates for an alpha-class EUVL exposure tool due to their low-defect levels and high quality surface finish. However, silicon has a large coefficient of thermal expansion that leads to unacceptable image distortion due to absorption of EUV light. A low thermal expansion glass or glass-ceramic is likely to be required in order to meet error budgets for the 70nm node and beyond. Since EUVL masks are used in reflection, they are coated with multilayers prior to patterning. Surface imperfections, such as polishing marks, particles, scratches, or digs, are potential nucleation sites for defects in the multilayer coating, which could result in the printed defects. Therefore we are accelerating developments in the defect reduction and surface finishing of low thermal expansion mask substrates in order to understand long-term issues in controlling printable defects, and to establish the infrastructure for supplying masks. In this paper, we explain the technical requirements for EUVL mask substrates and describe our efforts in establishing a SEMI standard for EUVL masks. We will also report on the early progress of our suppliers in producing low thermal-expansion mask substrates for our development activities.

  10. 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.

  11. Advances in Low-Defect Multilayers for EUVL Mask Blanks

    SciTech Connect

    Folta, J A; Davidson, J C; Larson, C C; Walton, C C; Kearney, P A

    2002-04-15

    Low-defect multilayer coatings are required to fabricate mask blanks for Extreme Ultraviolet Lithography (EUVL). The mask blanks consist of high reflectance E W multilayers on low thermal expansion substrates. A defect density of 0.0025 printable defects/cm{sup 2} for both the mask substrate and the multilayer is required to provide a mask blank yield of 60%. Current low defect multilayer coating technology allows repeated coating-added defect levels of 0.05/cm{sup 2} 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/cm{sup 2} 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/cm{sup 2}. 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.

  12. Detectability and printability of EUVL mask blank defects for the32 nm HP node

    SciTech Connect

    Cho, Wonil; Han, Hak-Seung; Goldberg, Kenneth A.; Kearney,Patrick A.; Jeon, Chan-Uk

    2007-08-01

    The readiness of a defect-free extreme ultraviolet lithography (EUVL) mask blank infrastructure is one of the main enablers for the insertion of EUVL technology into production. It is essential to have sufficient defect detection capability and understanding of defect printability to develop a defect-free EUVL mask blank infrastructure. The SEMATECH Mask Blank Development Center (MBDC) has been developing EUVL mask blanks with low defect densities with the Lasertec M1350 and M7360, the 1st and 2nd generations, respectively, of visible light EUVL mask blank inspection tools. Although the M7360 represents a significant improvement in our defect detection capability, it is time to start developing a 3rd generation tool for EUVL mask blank inspection. The goal of this tool is to detect all printable defects; therefore, understanding defect printability criteria is critical to this tool development. In this paper, we will investigate the defect detectability of a 2nd generation blank inspection tool and a patterned EUVL mask inspection tool. We will also compare the ability of the inspection tools to detect programmed defects whose printability has been estimated from wafer printing results and actinic aerial images results.

  13. Actinic defect counting statistics over 1 cm2 area of EUVL mask blank

    SciTech Connect

    Jeong, Seongtae; Lai, Chih-Wei; Rekawa, Seno; Walton, Chris W.; Bokor, Jeffrey

    2000-02-18

    As a continuation of comparison experiments between EUV inspection and visible inspection of defects on EUVL mask blanks, we report on the result of an experiment where the EUV defect inspection tool is used to perform at-wavelength defect counting over 1 cm{sup 2} of EUVL mask blank. Initial EUV inspection found five defects over the scanned area and the subsequent optical scattering inspection was able to detect all of the five defects. Therefore, if there are any defects that are only detectable by EUV inspection, the density is lower than the order of unity per cm2. An upgrade path to substantially increase the overall throughput of the EUV inspection system is also identified in the manuscript.

  14. Performance of actinic EUVL mask imaging using a zoneplate microscope

    SciTech Connect

    Goldberg, K; Naulleau, P; Barty, A; Rekawa, S; Kemp, C; Gunion, R; Salmassi, F; Gullikson, E; Anderson, E; Han, H

    2007-09-25

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is a dual-mode, scanning and imaging extreme-ultraviolet (EUV) microscope designed for pre-commercial EUV mask research. Dramatic improvements in image quality have been made by the replacement of several critical optical elements, and the introduction of scanning illumination to improve uniformity and contrast. We report high quality actinic EUV mask imaging with resolutions as low as 100-nm half-pitch, (20-nm, 5x wafer equivalent size), and an assessment of the imaging performance based on several metrics. Modulation transfer function (MTF) measurements show high contrast imaging for features sizes close to the diffraction-limit. An investigation of the illumination coherence shows that AIT imaging is much more coherent than previously anticipated, with {sigma} below 0.2. Flare measurements with several line-widths show a flare contribution on the order of 2-3% relative intensity in dark regions above the 1.3% absorber reflectivity on the test mask used for these experiments. Astigmatism coupled with focal plane tilt are the dominant aberrations we have observed. The AIT routinely records 250-350 high-quality images in numerous through-focus series per 8-hour shift. Typical exposure times range from 0.5 seconds during alignment, to approximately 20 seconds for high-resolution images.

  15. Performance of actinic EUVL mask imaging using a zoneplatemicroscope

    SciTech Connect

    Goldberg, Kenneth A.; Naulleau, Patrick P.; Barty, Anton; Rekawa,Senajith B.; Kemp, Charles D.; Gunion, Robert F.; Salmassi, Farhad; Gullikson, Eric M.; Anderson, Erik H.; Han, Hak-Seung

    2007-08-20

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is a dual-mode, scanning and imaging extreme-ultraviolet (EUV) microscope designed for pre-commercial EUV mask research. Dramatic improvements in image quality have been made by the replacement of several critical optical elements, and the introduction of scanning illumination to improve uniformity and contrast. We report high quality actinic EUV mask imaging with resolutions as low as 100-nm half-pitch, (20-nm, 5x wafer equivalent size), and an assessment of the imaging performance based on several metrics. Modulation transfer function (MTF) measurements show high contrast imaging for features sizes close to the diffraction-limit. An investigation of the illumination coherence shows that AIT imaging is much more coherent than previously anticipated, with {sigma} below 0.2. Flare measurements with several line-widths show a flare contribution on the order of 2-3% relative intensity in dark regions above the 1.3% absorber reflectivity on the test mask used for these experiments. Astigmatism coupled with focal plane tilt are the dominant aberrations we have observed. The AIT routinely records 250-350 high-quality images in numerous through-focus series per 8-hour shift. Typical exposure times range from 0.5 seconds during alignment, to approximately 20 seconds for high-resolution images.

  16. Evaluation of the Capability of a Multibeam Confocal Inspection System for Inspection of EUVL Mask Blanks

    NASA Astrophysics Data System (ADS)

    Stivers, Alan R.; Liang, Ted; Penn, Michael J.; Lieberman, Barry; Shelden, Gilbert V.; Folta, James A.; Larson, Cindy C.; Mirkarimi, Paul B.; Walton, Christopher C.; Gulliksong, Eric M.; Yi, Moonsuk

    2002-12-01

    Extreme ultraviolet (EUV) multilayer defects (phase defects) are a defect type unique to extreme ultraviolet lithography (EUVL) masks. A manufacturable inspection capability for these defects is key to the success of EUV lithography. Simulations of EUV scattering from multilayer defects suggest that defect printability is related to the phase error induced by the defect, which is in turn strongly coupled to the size of a multilayer surface protrusion or intrusion. We can adopt a strategy of measuring the multilayer surface to detect phase defects. During the past year a working group composed of members of Intel Corporation, Lawrence Berkeley and Lawrence Livermore National Laboratories, and International Sematech searched for a commercial tool for EUVL mask substrate and blank inspection. This working group established the tool requirements, methodologies for tool evaluation, collected data and recommended a supplier for further development with International Sematech. We collected data from several vendors and found that a multibeam confocal inspection (MCI) system had a capability significantly better than the tools used today. We will present our strategy, requirements, methodologies and results. We will discuss in detail our unique programmed substrate and multilayer defect masks used to support the tool selection, including their actinic characterization. We will present data that quantifies the inspection capability of the MCI system.

  17. Fiducial mark requirements from the viewpoints of actinic blank inspection tool for phase-defect mitigation on EUVL mask

    NASA Astrophysics Data System (ADS)

    Murachi, Tetsunori; Amano, Tsuyoshi; Oh, Sung H.

    2012-11-01

    For Extreme Ultra-Violet Lithography (EUVL), fabrication of defect free multi-layered (ML) mask blanks is one of the difficult challenges. ML defects come from substrate defects and adders during ML coating, cannot be removed, and are called as phase defect. If we can accept ML blanks with certain number of phase defects, the blank yield will be drastically up. In order to use such blanks, the phase defects need to be identified and located during ML blank defect inspection before absorber patterning. To locate phase defects on the blanks accurately and precisely, Fiducial Marks (FM) on ML blanks are needed for mask alignment and defect location information. The proposed requirement of defect location accuracy is less than 10 nm [1]. In addition to the previous study for which FMs were etched by Focused Ion Beam (FIB) [2], we fabricated FMs by resist exposure by E-Beam (EB) writer and etching process, and inspected FMs with EUV Actinic full-field mask Blank Inspection (ABI) prototype developed at MIRAI-Selete, EB writer and other mask inspection tools. Then we estimated FM registration accuracy for several line widths and depths. In this paper, we will present the result of feasibility study on the requirements of FM on EUVL mask by experiments to establish the phase defect mitigation method. And the optimum ranges of FM line width, depth, and fabrication method on EUVL mask based on above results are 3 - 5 m line width, not less than 100 nm depth FM etched into ML respectively.

  18. Evaluation of dry etching and defect repair of EUVL mask absorber layer

    NASA Astrophysics Data System (ADS)

    Abe, Tsukasa; Nishiguchi, Masaharu; Amano, Tsuyoshi; Motonaga, Toshiaki; Sasaki, Shiho; Mohri, Hiroshi; Hayashi, Naoya; Tanaka, Yuusuke; Nishiyama, Iwao

    2004-12-01

    EUVL mask process of absorber layer, buffer layer dry etching and defect repair were evaluated. TaGeN and Cr were selected for absorber layer and buffer layer, respectively. These absorber layer and buffer layer were coated on 6025 Qz substrate. Two dry etching processes were evaluated for absorber layer etching. One is CF4 plasma process and the other is Cl2 plasma process. Etch bias uniformity, selectivity, cross section profile and resist damage were evaluated for each process. Disadvantage of CF4 plasma process is low resist selectivity and Cl2 plasma process is low Cr selectivity. CF4 plasma process caused small absorber layer damage on isolate line and Cl2 plasma process caused Cr buffer layer damage. To minimize these damages overetch time was evaluated. Buffer layer process was also evaluated. Buffer layer process causes capping layer damage. Therefore, etching time was optimized. FIB-GAE and AFM machining were applied for absorber layer repair test. XeF2 gas was used for FIB-GAE. Good selectivity between absorber layer and buffer layer was obtained using XeF2 gas. However, XeF2 gas causes side etching of TaGeN layer. AFM machining repair technique was demonstrated for TaGeN layer repair.

  19. Report on EUVL Mask Substrate Development: Low-Expansion Substrate Finishing II

    SciTech Connect

    Tong, W.M.; Taylor, J.S.; Hector, S.D.; Shell, M.

    1999-12-08

    This report is a continuation of our assessment of the finishing of low thermal expansion material wafers obtained through three different commercial pathways. This quarter we have patterned and printed a ULE{reg_sign} wafer (Rodel 1) and saw no difference between its images and those from silicon wafer substrates. This further demonstrated that ULE{reg_sign} can be used as the EUVL mask substrate material. We have also evaluated substrates produced by three vendors: Hoya, General Optics, and Rodel. Consistent with our results reported last quarter, surface roughness of the bare substrates from all three companies does not depend on the position. For Hoya, the wafers it produced had a low roughness than those from last quarter. However, the cleanliness of the wafers needs to be improved. For General Optics, the wafer roughness has increased, and it was only able to deliver one wafer this quarter. General Optics will be replaced by Schott ML next quarter. For Rodel, one of its wafers (Rodel 1) that had been cleaned in-house showed excellent finishing and was selected to be patterned. We also observed that the sleeks on the substrates were smoothed by the ML coating. The other two Rodel wafers (Rodel 2 and Rodel 4) had too many defects and the roughness values derived from AFM are not reliable.

  20. One small step: world's first integrated EUVL process line

    NASA Astrophysics Data System (ADS)

    Roberts, Jeanette M.; Bacuita, Terence; Bristol, Robert L.; Cao, Heidi B.; Chandhok, Manish; Lee, Sang H.; Panning, Eric M.; Shell, Melissa; Zhang, Guojing; Rice, Bryan J.

    2005-05-01

    The Intel lithography roadmap calls for Extreme Ultraviolet Lithography (EUVL) to be used for the 32 nm node. With the installation of the EUV Micro-Exposure Tool (MET) complete, Intel now has the world's first integrated EUVL process line including the first commercial EUV exposure tool. This process line will be used to develop the EUV technology, including mask and resist, and to investigate issues such as defect printability. It also provides a test-bed to discover and resolve problems associated with using this novel technology in a fab (not lab) environment. Over 22,000 fields have been exposed, the discharge-produced plasma light source has operated for 50,000,000 pulses, 8 masks have been fabricated, and 8 resists have been characterized. The MET combines high resolution capability with Intel's advanced processing facilities to prepare EUVL for high-volume manufacturing (HVM). In this paper we review the MET installation and facilities, novel capabilities of the linked track, data on optics quality and modeled tool capability, and the MET mask fabrication process. We present data on tool performance including printing 45 nm 1/2 pitch lines with 160 nm depth of focus and 27 nm isolated lines. We show tool accuracy and repeatability data, and discuss issues uncovered during installation and use.

  1. Optics and multilayer coatings for EUVL systems

    SciTech Connect

    Soufli, R; Bajt, S; Hudyma, R M; Taylor, J S

    2008-03-21

    EUV lithography (EUVL) employs illumination wavelengths around 13.5 nm, and in many aspects it is considered an extension of optical lithography, which is used for the high-volume manufacturing (HVM) of today's microprocessors. The EUV wavelength of illumination dictates the use of reflective optical elements (mirrors) as opposed to the refractive lenses used in conventional lithographic systems. Thus, EUVL tools are based on all-reflective concepts: they use multilayer (ML) coated optics for their illumination and projection systems, and they have a ML-coated reflective mask.

  2. Analysis and control of thin film stresses during extreme ultraviolet lithography mask blank fabrication

    NASA Astrophysics Data System (ADS)

    Zheng, Liang

    2010-11-01

    Extreme Ultraviolet Lithography (EUVL) is the leading candidate for Next-Generation Lithography (NGL) in the sub-45 nm regime. One of the critical technical problems to be solved before the commercialization of EUVL is the control of image placement errors during EUVL mask blank fabrication. This paper focuses on the characterization of image placement errors induced by the thin film stresses during EUVL mask blank fabrication. Firstly, the causes and classifications of the stresses in the thin films were discussed. Then an analytical analysis was developed to reveal the effects of the thin film stresses on the distortions of the EUVL mask. Lastly, finite element (FE) models were established to simulate each process step in EUVL mask blank fabrication. The out-of-plane distortions (OPD) and inplane distortions (IPD) were tracked for each process step. The numerical results are compared with the analytical results to validate the FE models. Comparison indicated that numerical results and theoretical results agree very well with each other. The research in this paper provides a solid support for EUVL mask blank fabrication, theoretically and numerically. Further mounting and chucking procedures can keep image placement errors within the allotted error budget as well as provide the necessary flatness.

  3. Development of element technologies for EUVL

    NASA Astrophysics Data System (ADS)

    Kinoshita, Hiroo; Watanabe, Takeo; Harada, Tetsuo

    2015-08-01

    Thirty years have passed since the first report on extreme ultraviolet lithography (EUVL) was presented at the annual meeting of the Japanese Society of Applied Physics in 1986. This technology is now in the manufacturing development stage. The high-volume manufacturing of dynamic-random-access-memory (DRAM) chips with a line width of 15 nm is expected in 2016. However, there are critical development issues that remain: generating a stand-alone EUV source with a higher power and producing a mask inspection tool for obtaining zero-defect masks. The Center for EUVL at the University of Hyogo was established in 2010. At present, it utilizes various types of equipment, such as an EUV mask defect inspection tool, an interference-lithography system, a device for measuring the thickness of carbon contamination film deposited by resist outgassing, and reflectivity measurement systems.

  4. Challenges and solutions ensuring EUVL photomask integrity

    NASA Astrophysics Data System (ADS)

    Brux, O.; Dreß, P.; Schmalfuß, H.; Jonckheere, R.; Koolen-Hermkens, W.

    2012-06-01

    Industry roadmaps indicate that the introduction of Extreme Ultraviolet Lithography (EUVL) is on track for high volume manufacturing. Although, there has been significant progress in each of the individual subsets of the EUVL infrastructure, the absolute management of the process outside of the scanner and up to the point-of-exposure has been highlighted as critical requirement for the adoption of EUVL. Significant changes in the EUV system environment and mask architecture are driving a zero process tolerance level. Any unforeseen contamination introduced to the scanner environment from the EUV mask could cause considerable downtime and yield loss. Absolute mask integrity at the point-of-exposure must be guaranteed. EUV mask cleaning processes-of-record have been developed and introduced to the industry [1]. The issue is not longer "how to clean the mask" but, "how to keep it clean". With the introduction of EUVL, mask cleanliness extends out beyond the traditional mask cleaning tool. Complete control of contamination and/or particles during transportation, handling and storage will require a holistic approach to mask management. A new environment specifically for EUV mask integrity must be developed and fully tested for the sub 16nm half-pitch node introduction. The SUSS MaskTrack Pro (MTP) InSync was introduced as the solution for EUV mask integrity. SUSS demonstrated the fully automated handling of EUV masks into and out of a Dual Pod System [2]. Intrinsic cleanliness of each individual handling and storage step of the inner pod (EIP) and EUV mask inside the MTP InSync Tool was investigated and reported. A target specification of a PRP <= 0.08 as criterion for the cross contamination between EIP and the EUV reticle during handling within MTP InSync has been achieved and therefore proofing the applicability for the Dual Pod automation. Moreover an appropriate automated handling, other aspects like backside particle contamination and EIP cleanliness plays a

  5. 100-Picometer Interferometry for EUVL

    SciTech Connect

    Sommargren, G E; Phillion, D W; Johnson, M A; Nguyen, N O; Barty, A; Snell, F J; Dillon, D R; Bradsher, L S

    2002-03-18

    Future extreme ultraviolet lithography (EWL) steppers will, in all likelihood, have six-mirror projection cameras. To operate at the diffraction limit over an acceptable depth of focus each aspheric mirror will have to be fabricated with an absolute figure accuracy approaching 100 pm rms. We are currently developing visible light interferometry to meet this need based on modifications of our present phase shifting diffraction interferometry (PSDI) methodology where we achieved an absolute accuracy of 250pm. The basic PSDI approach has been further simplified, using lensless imaging based on computational diffractive back-propagation, to eliminate auxiliary optics that typically limit measurement accuracy. Small remaining error sources, related to geometric positioning, CCD camera pixel spacing and laser wavelength, have been modeled and measured. Using these results we have estimated the total system error for measuring off-axis aspheric EUVL mirrors with this new approach to interferometry.

  6. Accurate mask model for advanced nodes

    NASA Astrophysics Data System (ADS)

    Zine El Abidine, Nacer; Sundermann, Frank; Yesilada, Emek; Ndiaye, El Hadji Omar; Mishra, Kushlendra; Paninjath, Sankaranarayanan; Bork, Ingo; Buck, Peter; Toublan, Olivier; Schanen, Isabelle

    2014-07-01

    Standard OPC models consist of a physical optical model and an empirical resist model. The resist model compensates the optical model imprecision on top of modeling resist development. The optical model imprecision may result from mask topography effects and real mask information including mask ebeam writing and mask process contributions. For advanced technology nodes, significant progress has been made to model mask topography to improve optical model accuracy. However, mask information is difficult to decorrelate from standard OPC model. Our goal is to establish an accurate mask model through a dedicated calibration exercise. In this paper, we present a flow to calibrate an accurate mask enabling its implementation. The study covers the different effects that should be embedded in the mask model as well as the experiment required to model them.

  7. Evaluating Printability of Buried Native EUV Mask Phase Defects through a Modeling and Simulation Approach

    SciTech Connect

    Upadhyaya, Mihir; Jindal, Vibhu; Basavalingappa, Adarsh; Herbol, Henry; Harris-Jones, Jenah; Jang, Il-Yong; Goldberg, Kenneth A.; Mochi, Iacopo; Marokkey, Sajan; Demmerle, Wolfgang; Pistor, Thomas V.; Denbeaux, Gregory

    2015-03-16

    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 the 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.

  8. An automated image-based tool for pupil plane characterization of EUVL tools

    NASA Astrophysics Data System (ADS)

    Levinson, Zac; Smith, Jack S.; Fenger, Germain; Smith, Bruce W.

    2016-03-01

    Pupil plane characterization will play a critical role in image process optimization for EUV lithography (EUVL), as it has for several lithography generations. In EUVL systems there is additional importance placed on understanding the ways that thermally-induced system drift affect pupil variation during operation. In-situ full pupil characterization is therefore essential for these tools. To this end we have developed Quick Inverse Pupil (QUIP)—a software suite developed for rapid characterization of pupil plane behavior based on images formed by that system. The software consists of three main components: 1) an image viewer, 2) the model builder, and 3) the wavefront analyzer. The image viewer analyzes CDSEM micrographs or actinic mask micrographs to measure either CDs or through-focus intensity volumes. The software is capable of rotation correction and image registration with subpixel accuracy. The second component pre-builds a model for a particular imaging system to enable rapid pupil characterization. Finally, the third component analyzes the results from the image viewer and uses the optional pre-built model for inverse solutions of pupil plane behavior. Both pupil amplitude and phase variation can be extracted using this software. Inverse solutions are obtained through a model based algorithm which is built on top of commercial rigorous full-vector simulation software.

  9. Simulation study of CD variation caused by field edge effects and out-of-band radiation in EUVL

    NASA Astrophysics Data System (ADS)

    Gao, Weimin; Niroomand, Ardavan; Lorusso, Gian F.; Boone, Robert; Lucas, Kevin; Demmerle, Wolfgang

    2013-09-01

    Although extreme ultraviolet lithography (EUVL) remains a promising candidate for semiconductor device manufacturing of the 1x nm half pitch node and beyond, many technological burdens have to be overcome. The "field edge effect" in EUVL is one of them. The image border region of an EUV mask,also known as the "black border" (BB), reflects a few percent of the incident EUV light, resulting in a leakage of light into neighboring exposure fields, especially at the corner of the field where three adjacent exposures take place. This effect significantly impacts on CD uniformity (CDU) across the exposure field. To avoid this phenomenon, a light-shielding border is introduced by etching away the entire absorber and multi-layer (ML)at the image border region of the EUV mask. In this paper, we present a method of modeling the field edge effect (also called the BB effect) by using rigorous lithography simulation with a calibrated resist model. An additional "flare level" at the field edge is introduced on top of the exposure tool flare map to account for the BB effect. The parameters in this model include the reflectivity and the width of the BB, which are mainly determining the leakage of EUV light and its influence range, respectively. Another parameter is the transition width which represents the half shadow effect of the reticle masking blades. By setting the corresponding parameters, the simulation results match well the experimental results obtained at the imec's NXE:3100 EUV exposure tool. Moreover, these results indicate that the out-of-band (OoB) radiation also contributes to the CDU. Using simulation we can also determine the OoB effect rigorouslyusing the methodology of an "effective mask blank". The study in this paper demonstrates that the impact of BB and OoB effects on CDU can be well predicted by simulations.

  10. Demonstration of full-field patterning of 32 nm test chips using EUVL

    NASA Astrophysics Data System (ADS)

    Vandentop, Gilroy; Chandhok, Manish; Putna, Ernisse S.; Younkin, Todd R.; Clarke, James S.; Carson, Steven; Myers, Alan; Leeson, Michael; Zhang, Guojing; Liang, Ted; Murachi, Tetsunori

    2009-03-01

    EUV lithography is considered one of the options for high volume manufacturing (HVM) of 16 nm MPU node devices [1]. The benefits of high k1(~0.5) imaging enable EUVL to simplify the patterning process and ease design rule restrictions. However, EUVL with its unique imaging process - reflective optics and masks, vacuum operation, and lack of pellicle, has several challenges to overcome before being qualified for production. Thus, it is important to demonstrate the capability to integrate EUVL into existing process flows and characterize issues which could hamper yield. A patterning demonstration of Intel's 32 nm test chips using the ADT at IMEC [7] is presented, This test chip was manufactured using processes initially developed with the Intel MET [2-4] as well as masks made by Intel's mask shop [5,6]. The 32 nm node test chips which had a pitch of 112.5 nm at the trench layer, were patterned on the ADT which resulted in a large k1 factor of 1 and consequently, the trench process window was iso-focal with MEEF = 1. It was found that all mask defects detected by a mask pattern inspection tool printed on the wafer and that 90% of these originated from the substrate. We concluded that improvements are needed in mask defects, photospeed of the resist, overlay, and tool throughput of the tool to get better results to enable us to ultimately examine yield.

  11. Contrast Gain Control Model Fits Masking Data

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Solomon, Joshua A.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    We studied the fit of a contrast gain control model to data of Foley (JOSA 1994), consisting of thresholds for a Gabor patch masked by gratings of various orientations, or by compounds of two orientations. Our general model includes models of Foley and Teo & Heeger (IEEE 1994). Our specific model used a bank of Gabor filters with octave bandwidths at 8 orientations. Excitatory and inhibitory nonlinearities were power functions with exponents of 2.4 and 2. Inhibitory pooling was broad in orientation, but narrow in spatial frequency and space. Minkowski pooling used an exponent of 4. All of the data for observer KMF were well fit by the model. We have developed a contrast gain control model that fits masking data. Unlike Foley's, our model accepts images as inputs. Unlike Teo & Heeger's, our model did not require multiple channels for different dynamic ranges.

  12. Extreme Ultraviolet Lithography - Reflective Mask Technology

    SciTech Connect

    Walton, C.C.; Kearney, P.A.; Mirkarimi, P.B.; Bowers, J.M.; Cerjan, C.; Warrick, A.L.; Wilhelmsen, K.; Fought, E.; Moore, C.; Larson, C.; Baker, S.; Burkhart, S.C.; Hector, S.D.

    2000-05-09

    EUVL mask blanks consist of a distributed Bragg reflector made of 6.7nm-pitch bi-layers of MO and Si deposited upon a precision Si or glass substrate. The layer deposition process has been optimized for low defects, by application of a vendor-supplied but highly modified ion-beam sputter deposition system. This system is fully automated using SMIF technology to obtain the lowest possible environmental- and handling-added defect levels. Originally designed to coat 150mm substrates, it was upgraded in July, 1999 to 200 mm and has coated runs of over 50 substrates at a time with median added defects >100nm below 0.05/cm{sup 2}. These improvements have resulted from a number of ion-beam sputter deposition system modifications, upgrades, and operational changes, which will be discussed. Success in defect reduction is highly dependent upon defect detection, characterization, and cross-platform positional registration. We have made significant progress in adapting and extending commercial tools to this purpose, and have identified the surface scanner detection limits for different defect classes, and the signatures of false counts and non-printable scattering anomalies on the mask blank. We will present key results and how they have helped reduce added defects. The physics of defect reduction and mitigation is being investigated by a program on multilayer growth over deliberately placed perturbations (defects) of varying size. This program includes modeling of multilayer growth and modeling of defect printability. We developed a technique for depositing uniformly sized gold spheres on EUVL substrates, and have studied the suppression of the perturbations during multilayer growth under varying conditions. This work is key to determining the lower limit of critical defect size for EUV Lithography. We present key aspects of this work. We will summarize progress in all aspects of EUVL mask blank development, and present detailed results on defect reduction and mask blank

  13. 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.

  14. Automated mask creation from a 3D model using Faethm.

    SciTech Connect

    Schiek, Richard Louis; Schmidt, Rodney Cannon

    2007-11-01

    We have developed and implemented a method which given a three-dimensional object can infer from topology the two-dimensional masks needed to produce that object with surface micro-machining. The masks produced by this design tool can be generic, process independent masks, or if given process constraints, specific for a target process. This design tool calculates the two-dimensional mask set required to produce a given three-dimensional model by investigating the vertical topology of the model.

  15. Photoresists in extreme ultraviolet lithography (EUVL)

    NASA Astrophysics Data System (ADS)

    De Simone, Danilo; Vesters, Yannick; Vandenberghe, Geert

    2017-06-01

    The evolutionary advances in photosensitive material technology, together with the shortening of the exposure wavelength in the photolithography process, have enabled and driven the transistor scaling dictated by Moore's law for the last 50 years. Today, the shortening wavelength trend continues to improve the chips' performance over time by feature size miniaturization. The next-generation lithography technology for high-volume manufacturing (HVM) is extreme ultraviolet lithography (EUVL), using a light source with a wavelength of 13.5 nm. Here, we provide a brief introduction to EUVL and patterning requirements for sub-0-nm feature sizes from a photomaterial standpoint, discussing traditional and novel photoresists. Emphasis will be put on the novel class of metal-containing resists (MCRs) as well as their challenges from a manufacturing prospective.

  16. Visual backward masking: Modeling spatial and temporal aspects

    PubMed Central

    Hermens, Frouke; Ernst, Udo

    2008-01-01

    In modeling visual backward masking, the focus has been on temporal effects. More specifically, an explanation has been sought as to why strongest masking can occur when the mask is delayed with respect to the target. Although interesting effects of the spatial layout of the mask have been found, only a few attempts have been made to model these phenomena. Here, we elaborate a structurally simple model which employs lateral excitation and inhibition together with different neural time scales to explain many spatial and temporal aspects of backward masking. We argue that for better understanding of visual masking, it is vitally important to consider the interplay of spatial and temporal factors together in one single model. PMID:20517501

  17. Attentional gating models of object substitution masking.

    PubMed

    Põder, Endel

    2013-11-01

    Di Lollo, Enns, and Rensink (2000) proposed the computational model of object substitution (CMOS) to explain their experimental results with sparse visual maskers. This model supposedly is based on reentrant hypotheses testing in the visual system, and the modeled experiments are believed to demonstrate these reentrant processes in human vision. In this study, I analyze the main assumptions of this model. I argue that CMOS is a version of the attentional gating model and that its relationship with reentrant processing is rather illusory. The fit of this model to the data indicates that reentrant hypotheses testing is not necessary for the explanation of object substitution masking (OSM). Further, the original CMOS cannot predict some important aspects of the experimental data. I test 2 new models incorporating an unselective processing (divided attention) stage; these models are more consistent with data from OSM experiments. My modeling shows that the apparent complexity of OSM can be reduced to a few simple and well-known mechanisms of perception and memory. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  18. A model of PSF estimation for coded mask infrared imaging

    NASA Astrophysics Data System (ADS)

    Zhang, Ao; Jin, Jie; Wang, Qing; Yang, Jingyu; Sun, Yi

    2014-11-01

    The point spread function (PSF) of imaging system with coded mask is generally acquired by practical measure- ment with calibration light source. As the thermal radiation of coded masks are relatively severe than it is in visible imaging systems, which buries the modulation effects of the mask pattern, it is difficult to estimate and evaluate the performance of mask pattern from measured results. To tackle this problem, a model for infrared imaging systems with masks is presented in this paper. The model is composed with two functional components, the coded mask imaging with ideal focused lenses and the imperfection imaging with practical lenses. Ignoring the thermal radiation, the systems PSF can then be represented by a convolution of the diffraction pattern of mask with the PSF of practical lenses. To evaluate performances of different mask patterns, a set of criterion are designed according to different imaging and recovery methods. Furthermore, imaging results with inclined plane waves are analyzed to achieve the variation of PSF within the view field. The influence of mask cell size is also analyzed to control the diffraction pattern. Numerical results show that mask pattern for direct imaging systems should have more random structures, while more periodic structures are needed in system with image reconstruction. By adjusting the combination of random and periodic arrangement, desired diffraction pattern can be achieved.

  19. Progress on EUV mask fabrication for 32-nm technology node and beyond

    NASA Astrophysics Data System (ADS)

    Zhang, Guojing; Yan, Pei-Yang; Liang, Ted; Park, Seh-jin; Sanchez, Peter; Shu, Emily Y.; Ultanir, Erdem A.; Henrichs, Sven; Stivers, Alan; Vandentop, Gilroy; Lieberman, Barry; Qu, Ping

    2007-05-01

    Extreme ultraviolet lithography (EUVL) tool development achieved a big milestone last year as two full-field Alpha Demo Tools (ADT) were shipped to customers by ASML. In the future horizon, a full field "EUV1" exposure tool from Nikon will be available by the end of 20071 and the pre-production EUV exposure tools from ASML are targeted for 20092. It is essential that high quality EUVL masks can be made and delivered to the EUVL tool users to support the technology development. In the past year, we have demonstrated mask fabrication with low stress absorber deposition and good etch process control yielding a vertical etch profile and a mask CD control of 5.7 nm for 32 nm (1x) space and 7.4 nm for 32 nm (1x) lines. Mask pattern resolution of 15 nm (1x) dense lines was achieved. Full field reflective mask die-to-die inspection at a 125nm pixel size was demonstrated after low defect multilayer blanks became available. In this paper, we will present details of the Intel EUVL Mask Pilot Line progress in EUVL mask defect reduction, pattern CD performance, program defect mask design and inspection, in-house absorber film development and its performance, and EUVL metrology tool development. We will demonstrate an overall improvement in EUV mask manufacturing readiness due to our Pilot Line activities.

  20. Source mask optimization using 3D mask and compact resist models

    NASA Astrophysics Data System (ADS)

    El-Sewefy, Omar; Chen, Ao; Lafferty, Neal; Meiring, Jason; Chung, Angeline; Foong, Yee Mei; Adam, Kostas; Sturtevant, John

    2016-03-01

    Source Mask Optimization (SMO) has played an important role in technology setup and ground rule definition since the 2x nm technology node. While improvements in SMO algorithms have produced higher quality and more consistent results, the accuracy of the overall solution is critically linked to how faithfully the entire patterning system is modeled, from mask down to substrate. Fortunately, modeling technology has continued to advance to provide greater accuracy in modeling 3D mask effects, 3D resist behavior, and resist phenomena. Specifically, the Domain Decomposition Method (DDM) approximates the 3D mask response as a superposition of edge-responses.1 The DDM can be applied to a sectorized illumination source based on Hybrid-Hopkins Abbe approximation,2 which provides an accurate and fast solution for the modeling of 3D mask effects and has been widely used in OPC modeling. The implementation of DDM in the SMO flow, however, is more challenging because the shape and intensity of the source, unlike the case in OPC modeling, is evolving along the optimization path. As a result, it gets more complicated. It is accepted that inadequate pupil sectorization results in reduced accuracy in any application, however in SMO the required uniformity and density of pupil sampling is higher than typical OPC and modeling cases. In this paper, we describe a novel method to implement DDM in the SMO flow. The source sectorization is defined by following the universal pixel sizes used in SMO. Fast algorithms are developed to enable computation of edge signals from each fine pixel of the source. In this case, each pixel has accurate information to describe its contribution to imaging and the overall objective function. A more continuous angular spectrum from 3D mask scattering is thus captured, leading to accurate modeling of 3D mask effects throughout source optimization. This method is applied on a 2x nm middle-of-line layer test case. The impact of the 3D mask model accuracy on

  1. Modeling Spatial and Temporal Aspects of Visual Backward Masking

    ERIC Educational Resources Information Center

    Hermens, Frouke; Luksys, Gediminas; Gerstner, Wulfram; Herzog, Michael H.; Ernst, Udo

    2008-01-01

    Visual backward masking is a versatile tool for understanding principles and limitations of visual information processing in the human brain. However, the mechanisms underlying masking are still poorly understood. In the current contribution, the authors show that a structurally simple mathematical model can explain many spatial and temporal…

  2. Modeling Spatial and Temporal Aspects of Visual Backward Masking

    ERIC Educational Resources Information Center

    Hermens, Frouke; Luksys, Gediminas; Gerstner, Wulfram; Herzog, Michael H.; Ernst, Udo

    2008-01-01

    Visual backward masking is a versatile tool for understanding principles and limitations of visual information processing in the human brain. However, the mechanisms underlying masking are still poorly understood. In the current contribution, the authors show that a structurally simple mathematical model can explain many spatial and temporal…

  3. Model-based mask data preparation (MB-MDP) for ArF and EUV mask process correction

    NASA Astrophysics Data System (ADS)

    Hagiwara, Kazuyuki; Bork, Ingo; Fujimura, Aki

    2011-05-01

    Using Model-Based Mask Data Preparation (MB-MDP) complex masks with complex sub-resolution assist features (SRAFs) can be written in practical write times with today's leading-edge production VSB machines by allowing overlapping VSB shots. This simulation-based approach reduces shot count by taking advantage of the added flexibility in being able to overlap shots. The freedom to overlap shots, it turns out, also increases mask fidelity, CDU on the mask, and CDU on the wafer by writing sub-100nm mask features more accurately, and with better dose margin. This paper describes how overlapping shots enhance mask and wafer quality for various sub-100nm features on ArF masks. In addition, this paper describes how EUV mask accuracy can be enhanced uniquely by allowing overlapping shots.

  4. Integrated mask and optics simulations for mask corner rounding effect in OPC modeling

    NASA Astrophysics Data System (ADS)

    Xue, Jing; Deng, Zhijie; Koo, Kyoil; Shiely, James; Lee, Sooryong; Zhang, Yunqiang; Fan, Yongfa; Schmoeller, Thomas

    2010-09-01

    This paper presents a novel mask corner rounding (MCR) modeling approach based on Synopsys' Integrated Mask and Optics (IMO) modeling framework. The point spread functions of single, double, and elliptical Gaussians are applied to the IMO mask kernels to simulate MCR effects. The simulation results on two dimensional patterns indicate that the aerial image intensity variation is proportional to the MCR induced effective area variations for single type corners. The relationship may be reversed when multiple types of corners exist, where the corners close to the maximum intensity region have a greater influence than others. The CD variations due to MCR can be estimated by the effective area variation ratio and the image slope around the threshold. The good fitting results on line-end patterns indicate that the ΔCD is the quadratic function of the Gaussian standard deviations. OPC modeling on 28nm-node contacts shows that MCR has significant impact on model fitting results and process window controls. By considering the real mask geometry effects and allowing in-line calibration of model parameters, the IMO simulation framework significantly improves the OPC model accuracy, and maintains the calibration speed at a good level.

  5. Total source mask optimization: high-capacity, resist modeling, and production-ready mask solution

    NASA Astrophysics Data System (ADS)

    Fakhry, Moutaz; Granik, Yuri; Adam, Kostas; Lai, Kafai

    2011-11-01

    As the demand for taking Source Mask Optimization (SMO) technology to the full-chip level is increasing, the development of a flow that overcomes the limitations which hinder this technology's moving forward to the production level is a priority for Litho-Engineers. The aim of this work is to discuss advantages of using a comprehensive novel SMO flow that outperforms conventional techniques in areas of high capacity simulations, resist modeling and the production of a final manufacturable mask. We show results that indicate the importance of adding large number of patterns to the SMO exploration space, as well as taking into account resist effects during the optimization process and how this flow incorporates the final mask as a production solution. The high capacity of this flow increases the number of patterns and their area by a factor of 10 compared to other SMO techniques. The average process variability band is improved up to 30% compared to the traditional lithography flows.

  6. MASKED AREAS IN SHEAR PEAK STATISTICS: A FORWARD MODELING APPROACH

    SciTech Connect

    Bard, D.; Kratochvil, J. M.; Dawson, W.

    2016-03-09

    The statistics of shear peaks have been shown to provide valuable cosmological information beyond the power spectrum, and will be an important constraint of models of cosmology in forthcoming astronomical surveys. Surveys include masked areas due to bright stars, bad pixels etc., which must be accounted for in producing constraints on cosmology from shear maps. We advocate a forward-modeling approach, where the impacts of masking and other survey artifacts are accounted for in the theoretical prediction of cosmological parameters, rather than correcting survey data to remove them. We use masks based on the Deep Lens Survey, and explore the impact of up to 37% of the survey area being masked on LSST and DES-scale surveys. By reconstructing maps of aperture mass the masking effect is smoothed out, resulting in up to 14% smaller statistical uncertainties compared to simply reducing the survey area by the masked area. We show that, even in the presence of large survey masks, the bias in cosmological parameter estimation produced in the forward-modeling process is ≈1%, dominated by bias caused by limited simulation volume. We also explore how this potential bias scales with survey area and evaluate how much small survey areas are impacted by the differences in cosmological structure in the data and simulated volumes, due to cosmic variance.

  7. MASKED AREAS IN SHEAR PEAK STATISTICS: A FORWARD MODELING APPROACH

    SciTech Connect

    Bard, D.; Kratochvil, J. M.; Dawson, W.

    2016-03-10

    The statistics of shear peaks have been shown to provide valuable cosmological information beyond the power spectrum, and will be an important constraint of models of cosmology in forthcoming astronomical surveys. Surveys include masked areas due to bright stars, bad pixels etc., which must be accounted for in producing constraints on cosmology from shear maps. We advocate a forward-modeling approach, where the impacts of masking and other survey artifacts are accounted for in the theoretical prediction of cosmological parameters, rather than correcting survey data to remove them. We use masks based on the Deep Lens Survey, and explore the impact of up to 37% of the survey area being masked on LSST and DES-scale surveys. By reconstructing maps of aperture mass the masking effect is smoothed out, resulting in up to 14% smaller statistical uncertainties compared to simply reducing the survey area by the masked area. We show that, even in the presence of large survey masks, the bias in cosmological parameter estimation produced in the forward-modeling process is ≈1%, dominated by bias caused by limited simulation volume. We also explore how this potential bias scales with survey area and evaluate how much small survey areas are impacted by the differences in cosmological structure in the data and simulated volumes, due to cosmic variance.

  8. Masked areas in shear peak statistics. A forward modeling approach

    SciTech Connect

    Bard, D.; Kratochvil, J. M.; Dawson, W.

    2016-03-09

    The statistics of shear peaks have been shown to provide valuable cosmological information beyond the power spectrum, and will be an important constraint of models of cosmology in forthcoming astronomical surveys. Surveys include masked areas due to bright stars, bad pixels etc., which must be accounted for in producing constraints on cosmology from shear maps. We advocate a forward-modeling approach, where the impacts of masking and other survey artifacts are accounted for in the theoretical prediction of cosmological parameters, rather than correcting survey data to remove them. We use masks based on the Deep Lens Survey, and explore the impact of up to 37% of the survey area being masked on LSST and DES-scale surveys. By reconstructing maps of aperture mass the masking effect is smoothed out, resulting in up to 14% smaller statistical uncertainties compared to simply reducing the survey area by the masked area. We show that, even in the presence of large survey masks, the bias in cosmological parameter estimation produced in the forward-modeling process is ≈1%, dominated by bias caused by limited simulation volume. We also explore how this potential bias scales with survey area and evaluate how much small survey areas are impacted by the differences in cosmological structure in the data and simulated volumes, due to cosmic variance.

  9. Masked areas in shear peak statistics. A forward modeling approach

    DOE PAGES

    Bard, D.; Kratochvil, J. M.; Dawson, W.

    2016-03-09

    The statistics of shear peaks have been shown to provide valuable cosmological information beyond the power spectrum, and will be an important constraint of models of cosmology in forthcoming astronomical surveys. Surveys include masked areas due to bright stars, bad pixels etc., which must be accounted for in producing constraints on cosmology from shear maps. We advocate a forward-modeling approach, where the impacts of masking and other survey artifacts are accounted for in the theoretical prediction of cosmological parameters, rather than correcting survey data to remove them. We use masks based on the Deep Lens Survey, and explore the impactmore » of up to 37% of the survey area being masked on LSST and DES-scale surveys. By reconstructing maps of aperture mass the masking effect is smoothed out, resulting in up to 14% smaller statistical uncertainties compared to simply reducing the survey area by the masked area. We show that, even in the presence of large survey masks, the bias in cosmological parameter estimation produced in the forward-modeling process is ≈1%, dominated by bias caused by limited simulation volume. We also explore how this potential bias scales with survey area and evaluate how much small survey areas are impacted by the differences in cosmological structure in the data and simulated volumes, due to cosmic variance.« less

  10. Potential energy sputtering of EUVL materials

    SciTech Connect

    Pomeroy, J M; Ratliff, L P; Gillaspy, J D; Bajt, S

    2004-07-02

    Of the many candidates employed for understanding the erosion of critical Extreme Ultraviolet Lithography (EUVL) components, potential energy damage remains relatively uninvestigated. Unlike the familiar kinetic energy sputtering, which is a consequence of the momentum transferred by an ion to atoms in the target, potential energy sputtering occurs when an ion rapidly collects charge from the target as it neutralizes. Since the neutralization energy of a singly charged ion is typically on the order of 10 eV, potential energy effects are generally neglected for low charge state ions, and hence the bulk of the sputtering literature. As an ion's charge state is increased, the potential energy (PE) increases rapidly, e.g. PE(Xe{sup 1+})= 11 eV, PE(Xe{sup 10+}) = 810 eV, PE(Xe{sup 20+}) = 4.6 keV, etc. By comparison, the binding energy of a single atom on a surface is typically about 5 eV, so even relatively inefficient energy transfer mechanisms can lead to large quantities of material being removed, e.g. 25% efficiency for Xe{sup 10+} corresponds to {approx} 40 atoms/ion. By comparison, singly charged xenon ions with {approx} 20 keV of kinetic energy sputter only about 5 atoms/ion at normal incidence, and less than 1 atom/ion at typical EUV source energies. EUV light sources are optimized for producing approximately 10{sup 16} xenon ions per shot with an average charge state of q=10 in the core plasma. At operational rates of {approx}10 kHz, the number of ions produced per second becomes a whopping 10{sup 20}. Even if only one in a billion ions reaches the collector, erosion rates could reach {approx}10{sup 12} atoms per second, severely reducing the collector lifetime (for an average yield of 10 atoms/ion). In addition, efforts to reduce contamination effects may contribute to reduced neutralization and even larger potential energy damages rates (discussed further below). In order to provide accurate estimates for collector lifetimes and to develop mitigation schemes

  11. On-line simulations of models for backward masking.

    PubMed

    Francis, Gregory

    2003-11-01

    Five simulations of quantitative models of visual backward masking are available on the Internet at http://www.psych.purdue.edu/-gfrancis/Publications/BackwardMasking/. The simulations can be run in a Web browser that supports the Java programming language. This article describes the motivation for making the simulations available and gives a brief introduction as to how the simulations are used. The source code is available on the Web page, and this article describes how the code is organized.

  12. Mask model calibration for MPC applications utilizing shot dose assignment

    NASA Astrophysics Data System (ADS)

    Bork, Ingo; Buck, Peter; Paninjath, Sankaranarayanan; Mishra, Kushlendra; Bürgel, Christian; Standiford, Keith; Chua, Gek Soon

    2014-10-01

    Shrinking feature sizes and the need for tighter CD (Critical Dimension) control require the introduction of new technologies in mask making processes. One of those methods is the dose assignment of individual shots on VSB (Variable Shaped Beam) mask writers to compensate CD non-linearity effects and improve dose edge slope. Using increased dose levels only for most critical features, generally only for the smallest CDs on a mask, the change in mask write time is minimal while the increase in image quality can be significant. However, this technology requires accurate modeling of the mask effects, especially the CD/dose dependencies. This paper describes a mask model calibration flow for Mask Process Correction (MPC) applications with shot dose assignment. The first step in the calibration flow is the selection of appropriate test structures. For this work, a combination of linespace patterns as well as a series of contact patterns are used for calibration. Features sizes vary from 34 nm up to several micrometers in order to capture a wide range of CDs and pattern densities. After mask measurements are completed the results are carefully analyzed and measurements very close to the process window limitation and outliers are removed from the data set. One key finding in this study is that by including patterns exposed at various dose levels the simulated contours of the calibrated model very well match the SEM contours even if the calibration was based entirely on gauge based CD values. In the calibration example shown in this paper, only 1D line and space measurements as well as 1D contact measurements are used for calibration. However, those measurements include patterns exposed at dose levels between 75% and 150% of the nominal dose. The best model achieved in this study uses 2 e-beam kernels and 4 kernels for the simulation of development and etch effects. The model error RMS on a large range of CD down to 34 nm line CD is 0.71 nm. The calibrated model is then

  13. Impact of topographic mask models on scanner matching solutions

    NASA Astrophysics Data System (ADS)

    Tyminski, Jacek K.; Pomplun, Jan; Renwick, Stephen P.

    2014-03-01

    Of keen interest to the IC industry are advanced computational lithography applications such as Optical Proximity Correction of IC layouts (OPC), scanner matching by optical proximity effect matching (OPEM), and Source Optimization (SO) and Source-Mask Optimization (SMO) used as advanced reticle enhancement techniques. The success of these tasks is strongly dependent on the integrity of the lithographic simulators used in computational lithography (CL) optimizers. Lithographic mask models used by these simulators are key drivers impacting the accuracy of the image predications, and as a consequence, determine the validity of these CL solutions. Much of the CL work involves Kirchhoff mask models, a.k.a. thin masks approximation, simplifying the treatment of the mask near-field images. On the other hand, imaging models for hyper-NA scanner require that the interactions of the illumination fields with the mask topography be rigorously accounted for, by numerically solving Maxwell's Equations. The simulators used to predict the image formation in the hyper-NA scanners must rigorously treat the masks topography and its interaction with the scanner illuminators. Such imaging models come at a high computational cost and pose challenging accuracy vs. compute time tradeoffs. Additional complication comes from the fact that the performance metrics used in computational lithography tasks show highly non-linear response to the optimization parameters. Finally, the number of patterns used for tasks such as OPC, OPEM, SO, or SMO range from tens to hundreds. These requirements determine the complexity and the workload of the lithography optimization tasks. The tools to build rigorous imaging optimizers based on first-principles governing imaging in scanners are available, but the quantifiable benefits they might provide are not very well understood. To quantify the performance of OPE matching solutions, we have compared the results of various imaging optimization trials obtained

  14. Extreme ultraviolet lithography mask etch study and overview

    NASA Astrophysics Data System (ADS)

    Wu, Banqiu; Kumar, Ajay; Chandrachood, Madhavi; Sabharwal, Amitabh

    2013-04-01

    An overview of extreme ultraviolet lithography (EUVL) mask etch is presented and a EUVL mask etch study was carried out. Today, EUVL implementation has three critical challenges that hinder its adoption: extreme ultraviolet (EUV) source power, resist resolution-line width roughness-sensitivity, and a qualified EUVL mask. The EUVL mask defect challenges result from defects generated during blank preparation, absorber and multilayer deposition processes, as well as patterning, etching and wet clean processes. Stringent control on several performance criteria including critical dimension (CD) uniformity, etch bias, micro-loading, profile control, defect control, and high etch selectivity requirement to capping layer is required during the resist pattern duplication on the underlying absorber layer. EUVL mask absorbers comprise of mainly tantalum-based materials rather than chrome- or MoSi-based materials used in standard optical masks. Compared to the conventional chrome-based absorbers and phase shift materials, tantalum-based absorbers need high ion energy to obtain moderate etch rates. However, high ion energy may lower resist selectivity, and could introduce defects. Current EUVL mask consists of an anti-reflective layer on top of the bulk absorber. Recent studies indicate that a native oxide layer would suffice as an anti-reflective coating layer during the electron beam inspection. The absorber thickness and the material properties are optimized based on optical density targets for the mask as well as electromagnetic field effects and optics requirements of the patterning tools. EUVL mask etch processes are modified according to the structure of the absorber, its material, and thickness. However, etch product volatility is the fundamental requirement. Overlapping lithographic exposure near chip border may require etching through the multilayer, resulting in challenges in profile control and etch selectivity. Optical proximity correction is applied to further

  15. EUV mask inspection study for sub-20nm device

    NASA Astrophysics Data System (ADS)

    Shin, Inkyun; Yoon, Gisung; Na, Ji Hoon; Chung, Paul D. H.; Jeon, Chan-Uk

    2012-11-01

    Reflected light inspection has been used to inspect EUVL mask which consists of multi layers and metal absorber. However, sub-wavelength half pitch patterns and reflected inspection make unprecedented phenomenon like tone inversion. These lead EUV inspection more difficult in detectability and inspectability for separating out defects and false. In this study, we report the evaluation result of inspection dependency of illumination conditions like OAI(Off-Axis Illumination), sigma and polarization for sub-20nm EUVL PDM(programmed defect mask). With inspection of sub- 20nm device mask, we finally address the inspection feasibility for sub-20nm device and the future direction of inspection technology.

  16. Investigation and modeling of CPL mask profiles using OCD

    NASA Astrophysics Data System (ADS)

    Chen, Hsuan-Chen; Lin, Ren-Hao; Chen, Chien-Cheng; Huang, Cheng-Hsuan; Lien, Ta-Cheng; Chen, Chia-Jen; Lee, Gaston; Lee, Hsin-Chang; Yen, Anthony

    2016-05-01

    Mask profile of chromeless phase-shifting lithography (CPL) defined by OCD has been investigated. In CPL masks, unbalanced bombardments caused by different ion accelerations lead to the formation of micro-notch structures. A better understanding of micro-notch structures is essential for quality gating of mask processes to improve of CPL mask profiles. By measuring 12 of 16 elements of Mueller matrix, we are able to set up a model to simulate the depth of micro-notch structure profile which shows good correlation with TEM images. Moreover, values of CD, quartz etching depth and side wall angle acquired by OCD are presented and compared with those obtained by SEM, TEM and AFM, respectively.

  17. Model-based virtual VSB mask writer verification for efficient mask error checking and optimization prior to MDP

    NASA Astrophysics Data System (ADS)

    Pack, Robert C.; Standiford, Keith; Lukanc, Todd; Ning, Guo Xiang; Verma, Piyush; Batarseh, Fadi; Chua, Gek Soon; Fujimura, Akira; Pang, Linyong

    2014-10-01

    A methodology is described wherein a calibrated model-based `Virtual' Variable Shaped Beam (VSB) mask writer process simulator is used to accurately verify complex Optical Proximity Correction (OPC) and Inverse Lithography Technology (ILT) mask designs prior to Mask Data Preparation (MDP) and mask fabrication. This type of verification addresses physical effects which occur in mask writing that may impact lithographic printing fidelity and variability. The work described here is motivated by requirements for extreme accuracy and control of variations for today's most demanding IC products. These extreme demands necessitate careful and detailed analysis of all potential sources of uncompensated error or variation and extreme control of these at each stage of the integrated OPC/ MDP/ Mask/ silicon lithography flow. The important potential sources of variation we focus on here originate on the basis of VSB mask writer physics and other errors inherent in the mask writing process. The deposited electron beam dose distribution may be examined in a manner similar to optical lithography aerial image analysis and image edge log-slope analysis. This approach enables one to catch, grade, and mitigate problems early and thus reduce the likelihood for costly long-loop iterations between OPC, MDP, and wafer fabrication flows. It moreover describes how to detect regions of a layout or mask where hotspots may occur or where the robustness to intrinsic variations may be improved by modification to the OPC, choice of mask technology, or by judicious design of VSB shots and dose assignment.

  18. Model of visual contrast gain control and pattern masking

    NASA Technical Reports Server (NTRS)

    Watson, A. B.; Solomon, J. A.

    1997-01-01

    We have implemented a model of contrast gain and control in human vision that incorporates a number of key features, including a contrast sensitivity function, multiple oriented bandpass channels, accelerating nonlinearities, and a devisive inhibitory gain control pool. The parameters of this model have been optimized through a fit to the recent data that describe masking of a Gabor function by cosine and Gabor masks [J. M. Foley, "Human luminance pattern mechanisms: masking experiments require a new model," J. Opt. Soc. Am. A 11, 1710 (1994)]. The model achieves a good fit to the data. We also demonstrate how the concept of recruitment may accommodate a variant of this model in which excitatory and inhibitory paths have a common accelerating nonlinearity, but which include multiple channels tuned to different levels of contrast.

  19. 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

  20. A model of selective masking in chromatic detection.

    PubMed

    Shepard, Timothy G; Swanson, Emily A; McCarthy, Comfrey L; Eskew, Rhea T

    2016-07-01

    Narrowly tuned, selective noise masking of chromatic detection has been taken as evidence for the existence of a large number of color mechanisms (i.e., higher order color mechanisms). Here we replicate earlier observations of selective masking of tests in the (L,M) plane of cone space when the noise is placed near the corners of the detection contour. We used unipolar Gaussian blob tests with three different noise color directions, and we show that there are substantial asymmetries in the detection contours-asymmetries that would have been missed with bipolar tests such as Gabor patches. We develop a new chromatic detection model, which is based on probability summation of linear cone combinations, and incorporates a linear contrast energy versus noise power relationship that predicts how the sensitivity of these mechanisms changes with noise contrast and chromaticity. With only six unipolar color mechanisms (the same number as the cardinal model), the new model accounts for the threshold contours across the different noise conditions, including the asymmetries and the selective effects of the noises. The key for producing selective noise masking in the (L,M) plane is having more than two mechanisms with opposed L- and M-cone inputs, in which case selective masking can be produced without large numbers of color mechanisms.

  1. System for generating two-dimensional masks from a three-dimensional model using topological analysis

    DOEpatents

    Schiek, Richard

    2006-06-20

    A method of generating two-dimensional masks from a three-dimensional model comprises providing a three-dimensional model representing a micro-electro-mechanical structure for manufacture and a description of process mask requirements, reducing the three-dimensional model to a topological description of unique cross sections, and selecting candidate masks from the unique cross sections and the cross section topology. The method further can comprise reconciling the candidate masks based on the process mask requirements description to produce two-dimensional process masks.

  2. An advanced modeling approach for mask and wafer process simulation

    NASA Astrophysics Data System (ADS)

    Karakas, Ahmet; Elsen, Erich; Torunoglu, Ilhami; Andrus, Curtis

    2010-09-01

    A new modeling technique to accurately represent the mask and wafer process behavior is presented. The lithography simulation can be done in three steps: i) mask simulation, ii) latent image calculations and iii) resist process simulation. The leading edge designs, such as 32 nm and beyond, require higher-fidelity models to adequately represent each of these actual processes. Effects previously considered secondary, have become more pronounced with each new technology node. In this approach, we utilized separate physical models for both mask and wafer processes. We demonstrate that the residual errors can be further reduced when nonlinear mappers are used in addition. The advantage of the presented approach compared to standard curve-fitting or statistics-based models is its predictive power and adaptive nature. The physical model parameters were calibrated by a genetic algorithm whose details were outlined in [1]. The nonlinear mapper model parameters were identified by a gradient descent method. Given the computational requirements for a practical solution, our approach uses graphics processors as well as CPUs as computation hardware.

  3. Phase-induced amplitude apodization complex mask coronagraph mask fabrication, characterization, and modeling for WFIRST-AFTA

    NASA Astrophysics Data System (ADS)

    Kern, Brian; Guyon, Olivier; Belikov, Ruslan; Wilson, Daniel; Muller, Richard; Sidick, Erkin; Balasubramanian, Bala; Krist, John; Poberezhskiy, Ilya; Tang, Hong

    2016-01-01

    This work describes the fabrication, characterization, and modeling of a second-generation occulting mask for a phase-induced amplitude apodization complex mask coronagraph, designed for use on the WFIRST-AFTA mission. The mask has many small features (˜micron lateral scales) and was fabricated at the Jet Propulsion Laboratory Microdevices Laboratory, then characterized using a scanning electron microscope, atomic force microscope, and optical interferometric microscope. The measured fabrication errors were then fed to a wavefront control model which predicts the contrast performance of a full coronagraph. The expected coronagraphic performance using this mask is consistent with observing ˜15 planetary targets with WFIRST-AFTA in a reasonable time (<1 day/target).

  4. Binaural Masking: An Analysis of Models.

    DTIC Science & Technology

    1988-04-15

    predictions of the model suggest that the commonly used combination of the 2AFC procedure and the "l up 2 down" rule is the least efficient method of...consistent, but generally show the combination of the 2AFC procedure and the "l up 2 down" rule to be one of the least efficient methods. A manuscript is

  5. Binaural Masking: An Analysis of Models

    DTIC Science & Technology

    1989-08-01

    model suggest that the commonly used (’mbination of the 2AFC procedure and the " I up 2 down" rule is the least efficienl mellod of estimating a...geneirally show the combination of the 2AFC procedLire and (he "I up 2 down" rule to be one of ihe least efficient nethods. A manuscript has been

  6. Mask process matching using a model based data preparation solution

    NASA Astrophysics Data System (ADS)

    Dillon, Brian; Saib, Mohamed; Figueiro, Thiago; Petroni, Paolo; Progler, Chris; Schiavone, Patrick

    2015-10-01

    Process matching is the ability to precisely reproduce the signature of a given fabrication process while using a different one. A process signature is typically described as systematic CD variation driven by feature geometry as a function of feature size, local density or distance to neighboring structures. The interest of performing process matching is usually to address differences in the mask fabrication process without altering the signature of the mask, which is already validated by OPC models and already used in production. The need for such process matching typically arises from the expansion of the production capacity within the same or different mask fabrication facilities, from the introduction of new, perhaps more advanced, equipment to deliver same process of record masks and/or from the re-alignment of processes which have altered over time. For state-of-the-art logic and memory mask processes, such matching requirements can be well below 2nm and are expected to reduce below 1nm in near future. In this paper, a data preparation solution for process matching is presented and discussed. Instead of adapting the physical process itself, a calibrated model is used to modify the data to be exposed by the source process in order to induce the results to match the one obtained while running the target process. This strategy consists in using the differences among measurements from the source and target processes, in the calibration of a single differential model. In this approach, no information other than the metrology results is required from either process. Experimental results were obtained by matching two different processes at Photronics. The standard deviation between both processes was of 2.4nm. After applying the process matching technique, the average absolute difference between the processes was reduced to 1.0nm with a standard deviation of 1.3nm. The methods used to achieve the result will be described along with implementation considerations, to

  7. Pattern analysis based models of masking by spatially separated sound sources

    NASA Astrophysics Data System (ADS)

    Gilkey, Robert H.

    1992-06-01

    One goal of this program is to examine masking among spatially separated sound sources. The results indicate that masking release on the order of 8-20 dB can be observed in free-field masking situations when the signal and the masker are spatially separated by 90 degrees. This magnitude of masking release is comparable to that observed in traditional binaural masking level difference experiments, where the stimuli are presented through headphones. However, while masking release observed in headphone studies is typically assumed to be based on interaural differences in phase or on interaural differences in intensity, we observed substantial masking release in the median plane where interaural differences are minimal. Our own headphone masking research is also questioning traditional models of binaural masking. Work is underway to develop a neural network based model of sound localization. The results of these studies will have implications for the development of virtual environments and auditory displays.

  8. Chromatic induction and contrast masking: similar models, different goals?

    NASA Astrophysics Data System (ADS)

    Jiménez, Sandra; Otazu, Xavier; Laparra, Valero; Malo, Jesús

    2013-03-01

    Normalization of signals coming from linear sensors is an ubiquitous mechanism of neural adaptation.1 Local interaction between sensors tuned to a particular feature at certain spatial position and neighbor sensors explains a wide range of psychophysical facts including (1) masking of spatial patterns, (2) non-linearities of motion sensors, (3) adaptation of color perception, (4) brightness and chromatic induction, and (5) image quality assessment. Although the above models have formal and qualitative similarities, it does not necessarily mean that the mechanisms involved are pursuing the same statistical goal. For instance, in the case of chromatic mechanisms (disregarding spatial information), different parameters in the normalization give rise to optimal discrimination or adaptation, and different non-linearities may give rise to error minimization or component independence. In the case of spatial sensors (disregarding color information), a number of studies have pointed out the benefits of masking in statistical independence terms. However, such statistical analysis has not been performed for spatio-chromatic induction models where chromatic perception depends on spatial configuration. In this work we investigate whether successful spatio-chromatic induction models,6 increase component independence similarly as previously reported for masking models. Mutual information analysis suggests that seeking an efficient chromatic representation may explain the prevalence of induction effects in spatially simple images.

  9. Mask roughness induced LER control and mitigation: aberrations sensitivity study and alternate illumination scheme

    SciTech Connect

    McClinton, Brittany M.; Naulleau, Patrick P.

    2011-03-11

    Here we conduct a mask-roughness-induced line-edge-roughness (LER) aberrations sensitivity study both as a random distribution amongst the first 16 Fringe Zernikes (for overall aberration levels of 0.25, 0.50, and 0.75nm rms) as well as an individual aberrations sensitivity matrix over the first 37 Fringe Zernikes. Full 2D aerial image modeling for an imaging system with NA = 0.32 was done for both the 22-nm and 16-nm half-pitch nodes on a rough mask with a replicated surface roughness (RSR) of 100 pm and a correlation length of 32 nm at the nominal extreme-ultraviolet lithography (EUVL) wavelength of 13.5nm. As the ideal RSR value for commercialization of EUVL is 50 pm and under, and furthermore as has been shown elsewhere, a correlation length of 32 nm of roughness on the mask sits on the peak LER value for an NA = 0.32 imaging optic, these mask roughness values and consequently the aberration sensitivity study presented here, represent a worst-case scenario. The illumination conditions were chosen based on the possible candidates for the 22-nm and 16-nm half-pitch nodes, respectively. In the 22-nm case, a disk illumination setting of {sigma} = 0.50 was used, and for the 16-nm case, crosspole illumination with {sigma} = 0.10 at an optimum offset of dx = 0 and dy = .67 in sigma space. In examining how to mitigate mask roughness induced LER, we considered an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a 'strip'. While this illumination surprisingly provides minimal improvement to the LER as compared to several alternate illumination schemes, the overall imaging quality in terms of image-log-slope (ILS) and contrast is improved.

  10. Techniques to measure force uniformity of electrostatic chucks for EUV mask clamping

    NASA Astrophysics Data System (ADS)

    Veeraraghavan, Sathish; Sohn, Jaewoong; Turner, Kevin T.

    2007-10-01

    Extreme ultraviolet lithography (EUVL) has stringent requirements on image placement (IP) errors in order to allow for the patterning of devices with critical dimensions (CD) in the sub-32 nm regime. A major contributor to IP error in EUVL is non-flatness of the mask. Electrostatic chucks are used to support and flatten masks in EUVL scanners. Proper operation requires that the electrostatic forces generated by the chuck be of sufficient magnitude and be uniform over the entire chucking area. Hence, there is a need to measure the clamping pressure distribution to properly characterize performance of electrostatic chucks. This paper discusses two methods to measure electrostatic pressure magnitude and uniformity by examining the distortion of thin substrates (wafers) during chucking. In the first method, a wafer with lithographically defined mesas is chucked with the mesas located at the interface between the wafer and the chuck and thus results in a void near the mesa after chucking. Analytical and finite element models were used to relate the resulting void radius to the electrostatic pressure and used to assess the feasibility of the technique. Measurements of pressure on a slab chuck were conducted to demonstrate the mesa measurement approach. The second measurement method examines the deflection of a wafer between pins on a pin chuck in order to estimate the local pressure. A 3D FE model was developed to predict the deformation of the wafer between the pins as a function of applied pressure. The model was used to assess the feasibility of the approach and provide guidance on selecting appropriate substrates for use in such experiments.

  11. Better numerical model for shape-dependent dose margin correction using model-based mask data preparation

    NASA Astrophysics Data System (ADS)

    Kimura, Yasuki; Kubota, Takao; Kouno, Kenji; Hagiwara, Kazuyuki; Matsushita, Shohei; Hara, Daisuke

    2013-06-01

    For the mask making community, maintaining acceptable dose margin has been recognized as a critical factor in the mask-making process. This is expected to be more critical for 20nm logic node masks and beyond. To deal with this issue, model-based mask data preparation (MB-MDP) had been presented as a useful method to obtain sufficient dose margin for these complex masks, in addition to reducing shot count. When the MB-MDP approach is applied in the actual mask production, the prediction of the dose margin and the CD in the finished mask is essential. This paper describes an improved model of mask process which predicts dose margin and CD in finished masks better compared with the single Gaussian model presented in previous work. The better predictions of this simple numerical model are confirmed with simulation by D2S and actual mask written by HOYA using JEOL JBX-3200MV.

  12. Analysis of a relation between the spatial frequency of electrostatic chuck and induced mask inplane distortion (IPD)

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takeshi; Ota, Kazuya; Nishimura, Naosuke; Warisawa, Shin'ichi; Ishihara, Sunao

    2009-03-01

    Due to potential applications of Extreme Ultraviolet Lithography (EUVL) to 22 nm half-pitch (hp) generations, EUVL is well researched. However, current SEMI standards about the chuck are based on only the local slope of roughness. Herein chuck standards, which consider the spatial frequency of the chuck surface roughness as well as the local slope of the shape, are proposed by examining the chuck roughness. To prevent a mask pattern shift when an EUVL mask is clamped by an electrostatic chuck, the roughness height must be limited. Thus, the in-plane distortion (IPD) and out-of-plane distortion (OPD) are introduced to evaluate the mask pattern shift. This research utilizes ANSYS to evaluate the relationship between the spatial frequency of chuck roughness and IPD/OPD induced on the mask surface after an EUVL mask is clamped by the chuck. The IPD depends on the local slope of the surface roughness shape of the electrostatic chuck (ESC) as well as the spatial frequency of the roughness. Therefore, re-polishing the chuck surface can decrease IPD. Moreover, the spatial frequency of roughness must be considered when a mask pattern shift correction is performed according to the surface roughness shape of the EUVL mask and ESC.

  13. 3D mask modeling with oblique incidence and mask corner rounding effects for the 32nm node

    NASA Astrophysics Data System (ADS)

    Saied, Mazen; Foussadier, Franck; Belledent, Jérôme; Trouiller, Yorick; Schanen, Isabelle; Yesilada, Emek; Gardin, Christian; Urbani, Jean Christophe; Sundermann, Frank; Robert, Frédéric; Couderc, Christophe; Vautrin, Florent; LeCam, Laurent; Kerrien, Gurwan; Planchot, Jonathan; Martinelli, Catherine; Wilkinson, Bill; Rody, Yves; Borjon, Amandine; Morgana, Nicolo; Di-Maria, Jean-Luc; Farys, Vincent

    2007-10-01

    The perpetual shrinking in critical dimensions in semiconductor devices is driving the need for increased resolution in optical lithography. Increasing NA to gain resolution also increases Optical Proximity Correction (OPC) model complexity. Some optical effects which have been completely neglected in OPC modeling become important. Over the past few years, off-axis illumination has been widely used to improve the imaging process. OPC models which utilize such illumination still use the thin film mask approximation (Kirchhoff approach), during optical model generation, which utilizes a normal incidence. However, simulating a three dimensional mask near-field using an off-axis illumination requires OPC models to introduce oblique incidence. In addition, the use of higher NA systems introduces high obliquity field components that can no longer be assimilated as normal incident waves. The introduction of oblique incidence requires other effects, such as corner rounding of mask features, to be considered, that are seldom taken into account in OPC modeling. In this paper, the effects of oblique incidence and corner rounding of mask features on resist contours of 2D structures (i.e. line-ends and corners) are studied. Rigorous electromagnetic simulations are performed to investigate the scattering properties of various lithographic 32nm node mask structures. Simulations are conducted using a three dimensional phase shift mask topology and an off-axis illumination at high NA. Aerial images are calculated and compared with those obtained from a classical normal incidence illumination. The benefits of using an oblique incidence to improve hot-spot prediction will be discussed.

  14. Calibration of a Spatial-Temporal Discrimination Model from Forward, Simultaneous, and Backward Masking

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J.; Beard, B. L.; Stone, Leland (Technical Monitor)

    1997-01-01

    We have been developing a simplified spatial-temporal discrimination model similar to our simplified spatial model in that masking is assumed to be a function of the local visible contrast energy. The overall spatial-temporal sensitivity of the model is calibrated to predict the detectability of targets on a uniform background. To calibrate the spatial-temporal integration functions that define local visible contrast energy, spatial-temporal masking data are required. Observer thresholds were measured (2IFC) for the detection of a 12 msec target stimulus in the presence of a 700 msec mask. Targets were 1, 3 or 9 c/deg sine wave gratings. Masks were either one of these gratings or two of them combined. The target was presented in 17 temporal positions with respect to the mask, including positions before, during and after the mask. Peak masking was found near mask onset and offset for 1 and 3 c/deg targets, while masking effects were more nearly uniform during the mask for the 9 c/deg target. As in the purely spatial case, the simplified model can not predict all the details of masking as a function of masking component spatial frequencies, but overall the prediction errors are small.

  15. Calibration of a Spatial-Temporal Discrimination Model from Forward, Simultaneous, and Backward Masking

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J.; Beard, B. L.; Stone, Leland (Technical Monitor)

    1997-01-01

    We have been developing a simplified spatial-temporal discrimination model similar to our simplified spatial model in that masking is assumed to be a function of the local visible contrast energy. The overall spatial-temporal sensitivity of the model is calibrated to predict the detectability of targets on a uniform background. To calibrate the spatial-temporal integration functions that define local visible contrast energy, spatial-temporal masking data are required. Observer thresholds were measured (2IFC) for the detection of a 12 msec target stimulus in the presence of a 700 msec mask. Targets were 1, 3 or 9 c/deg sine wave gratings. Masks were either one of these gratings or two of them combined. The target was presented in 17 temporal positions with respect to the mask, including positions before, during and after the mask. Peak masking was found near mask onset and offset for 1 and 3 c/deg targets, while masking effects were more nearly uniform during the mask for the 9 c/deg target. As in the purely spatial case, the simplified model can not predict all the details of masking as a function of masking component spatial frequencies, but overall the prediction errors are small.

  16. Comparison of Ventilation With One-Handed Mask Seal With an Intraoral Mask Versus Conventional Cuffed Face Mask in a Cadaver Model: A Randomized Crossover Trial.

    PubMed

    Amack, Andrew J; Barber, Gary A; Ng, Patrick C; Smith, Thomas B; April, Michael D

    2017-01-01

    We compare received minute volume with an intraoral mask versus conventional cuffed face mask among medics obtaining a 1-handed mask seal on a cadaver model. This study comprised a randomized crossover trial of adult US Army combat medic volunteers participating in a cadaver laboratory as part of their training. We randomized participants to obtain a 1-handed mask seal during ventilation of a fresh unembalmed cadaver, first using either an intraoral airway device or conventional cuffed face mask. Participants obtained a 1-handed mask seal while a ventilator delivered 10 standardized 750-mL breaths during 1 minute. After a 5-minute rest period, they repeated the study with the alternative mask. The primary outcome measure was received minute volume as measured by a respirometer. Of 27 recruited participants, all completed the study. Median received minute volume was higher with the intraoral mask compared with conventional cuffed mask by 1.7 L (95% confidence interval 1.0 to 1.9 L; P<.001). The intraoral mask resulted in greater received minute volume received compared with conventional cuffed face mask during ventilation with a 1-handed mask seal in a cadaver model. The intraoral mask may prove a useful airway adjunct for ventilation. Copyright © 2016 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  17. Imaging performance improvements by EUV mask stack optimization

    NASA Astrophysics Data System (ADS)

    Davydova, Natalia; van Setten, Eelco; de Kruif, Robert; Oorschot, Dorothe; Dusa, Mircea; Wagner, Christian; Jiang, Jiong; Liu, Wei; Kang, Hoyoung; Liu, Hua-yu; Spies, Petra; Wiese, Nils; Waiblinger, Markus

    2011-03-01

    EUVL requires the use of reflective optics including a reflective mask. The mask contains a reflecting multilayer, tuned for 13.5 nm light, and an absorber which defines the dark areas. The EUV mask itself is a complex optical element with many more parameters than just the mask CD uniformity of the patterned features that impact the final wafer CDU. One of these parameters is absorber height. It has been shown that the oblique incidence of light in combination with the small wavelength compared to the mask topography causes a so-called shadowing effect manifesting itself particularly in an HV wafer CD offset. It was also shown that this effect can be essentially decreased by reducing absorber height and, in addition, it can be corrected by means of OPC. However, reduction of absorber height has a side effect that is an increased reflectivity of a mask black border resulting in field-to-field stray light due to parasitic reflections. One of the solutions to this problem is optical process correction (OPC) at field edges. In this paper we will show experimental data obtained on ASML EUV Alpha tool illustrating the black border effect and will demonstrate that this effect can be accurately predicted by Brion Tachyon EUV model allowing for a significant cross field CD uniformity improvement with mask layout correction technique. Also we show by means of rigorous 3D simulations that it is possible to improve the imaging performance significantly by performing global optimization of mask absorber height and mask bias in order to increase exposure latitude, decrease CD sensitivity to mask making variations such as CD mask error and absorber stack height variations. By sacrificing some exposure latitude throughput of exposure tool can be increased essentially and HV mask biasing can be reduced. For four masks with different absorber thicknesses from 44 nm to 87 nm it is proven experimentally by means of the EUV Alpha tool exposures of 27 nm L/S that the absorber thickness

  18. Process liability evaluation for beyond 22nm node using EUVL

    NASA Astrophysics Data System (ADS)

    Tawarayama, Kazuo; Aoyama, Hajime; Matsunaga, Kentaro; Arisawa, Yukiyasu; Uno, Taiga; Magoshi, Shunko; Kyoh, Suigen; Nakajima, Yumi; Inanami, Ryoichi; Tanaka, Satoshi; Kobiki, Ayumi; Kikuchi, Yukiko; Kawamura, Daisuke; Takai, Kosuke; Murano, Koji; Hayashi, Yumi; Mori, Ichiro

    2010-04-01

    Extreme ultraviolet lithography (EUVL) is the most promising candidate for the manufacture of devices with a half pitch of 32 nm and beyond. We are now evaluating the process liability of EUVL in view of the current status of lithography technology development. In a previous study, we demonstrated the feasibility of manufacturing 32-nm-node devices by means of a wafer process that employed the EUV1, a full-field step-and-scan exposure tool. To evaluate yield, a test pattern was drawn on a multilayer resist and exposed. After development, the pattern was replicated in SiO2 film by etching, and metal wires were formed by a damascene process. Resolution enhancement is needed to advance to the 22- nm node and beyond, and a practical solution is off-axis illumination (OAI). This paper presents the results of a study on yield improvement that used a 32-nm-node test chip, and also clarifies a critical issue in the use of EUVL in a wafer process for device manufacture at the 22-nm node and beyond.

  19. The analysis of EUV mask defects using a wafer defect inspection system

    NASA Astrophysics Data System (ADS)

    Cho, Kyoung-Yong; Park, Joo-On; Park, Changmin; Lee, Young-Mi; Kang, In-Yong; Yeo, Jeong-Ho; Choi, Seong-Woon; Park, Chan-Hoon; Lange, Steven R.; Cho, SungChan; Danen, Robert M.; Kirk, Gregory L.; Pae, Yeon-Ho

    2010-04-01

    EUVL is the strongest candidate for a sub-20nm lithography solution after immersion double-patterning. There are still critical challenges for EUVL to address to become a mature technology like today's litho workhorse, ArF immersion. Source power and stability, resist resolution and LWR (Line Width Roughness), mask defect control and infrastructure are listed as top issues. Source power has shown reasonably good progress during the last two years. Resist resolution was proven to resolve 32nm HP (Half Pitch) lines and spaces with good process windows even though there are still concerns with LWR. However, the defectivity level of blank masks is still three orders of magnitude higher than the requirement as of today. In this paper, mask defect control using wafer inspection is studied as an alternative solution to mask inspection for detection of phase defects on the mask. A previous study suggested that EUVL requires better defect inspection sensitivity than optical lithography because EUVL will print smaller defects. Improving the defect detection capability involves not only inspection system but also wafer preparation. A few parameters on the wafer, including LWR and wafer stack material and thickness are investigated, with a goal of enhancing the defect capture rate for after development inspection (ADI) and after cleaning inspection (ACI). In addition to defect sensitivity an overall defect control methodology will be suggested, involving mask, mask inspection, wafer print and wafer inspection.

  20. Modeling mask pellicle effects for OPC/RET

    NASA Astrophysics Data System (ADS)

    Zavyalova, Lena; Song, Hua; Lucas, Kevin; Zhang, Qiaolin; Shiely, James

    2008-05-01

    A thin membrane called a pellicle is commonly used to protect the mask from contamination. The thickness of the pellicle material is usually optimized at normal incident angle to minimize the thin film optics interference effect by cancellation of the reflected light from the top ambient/pellicle interface with the reflected light from the bottom pellicle/ambient interface. In previous lithography generations the maximum angle collected by the projection lens (NA) was low, hence the normal incidence approach was valid, and the transmission loss for the non-normal incident angles was minor and ignored. With modern hyper-NA imaging for 45nm and smaller nodes, this transmission attenuation becomes larger. The more stringent CD error budget of these technology nodes demands that this effect should not be ignored anymore. In this paper, we present a modeling framework that takes into consideration the high angle pellicle effects. Taking the pellicle's polarization state dependent transmission data, which can be measured or computed with a rigorous simulator, we first present the pellicle transmission property as Jones matrices on the pupil plane, and then incorporate pellicle modeling into the existing vector model for lithography imaging computation. Existing modeling software for modelbased OPC/RET tools is easily enhanced to include pellicle modeling. Using Synopsys' OPC/RET modeling software ProGen, we investigate the necessity of pellicle effect modeling for mask synthesis for 45 nm and smaller nodes. Numerical experiments are performed to study the impact of illumination polarization on the accuracy of lithography simulation and the quality of OPC results.

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

    SciTech Connect

    Yan, Pei-Yang; Zhang, Guojing; Gullickson, Eric M.; Goldberg, Kenneth 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.

  2. Simple model for spatial-frequency masking and contrast discrimination

    NASA Astrophysics Data System (ADS)

    Barten, Peter G. J.

    1995-04-01

    After some principal considerations about noise and the psychometric function,we present a model for the masking of a spatial frequency patten by nonwhite noise. From threshold elevation measurements by Stromeyer and Julesz, we derive a distribution function for the disturbing effect of one frequency on the detection of another frequency. We apply the resulting formulas on contrast sensitivity measurements with nonwhite noise by van Meeteren and Valeton. Next we use the same principles to derive a simple model for contrast discrimination. We consider the pedestal modulation as a nonwhite noise source of a single spatial frequency that hampers contrast detection. We show that contrast discrimination plots for different spatial frequencies will coincide if they are plotted in a normalized way. After a slight practical correction the model appears to be in very good agreement with measurements of various authors published in literature.

  3. DIET Processes on Ruthenium Surfaces Related to Extreme Ultraviolet Lithography (EUVL)

    SciTech Connect

    Yakshinskiy, B.; Wasielewski, R; Loginova, E; Hedhili, M; Madey, T

    2008-01-01

    The aim of this work is to provide insights into desorption induced by electronic transitions (DIET) processes that affect the reflectivity of ruthenium-capped Mo/Si multilayer mirrors working under EUVL (extreme ultraviolet lithography) operating conditions (high vacuum, and 13.5 nm (92 eV) photons). Critical issues are associated with possible oxidation of the 2 nm thick Ru capping layer due to the inevitable background pressure of H{sub 2}O, and carbon build up due to background hydrocarbons. In the present work, we discuss aspects of the radiation-induced surface chemistry of Ru irradiated by 100 eV electrons and 92 eV photons. The cross section for electron-stimulated desorption of oxygen from O-covered Ru is 6 x 10{sup -19} cm{sup 2}. Carbon accumulation several nm thick occurs on the Ru surface during electron irradiation in methyl methacrylate (MMA) vapor, a model background impurity hydrocarbon. Radiation damage by low-energy secondary electrons is believed to dominate over direct photoexcitation of adsorbates under EUVL conditions. The secondary electron yield from Ru varies strongly with photon energy, and is 0.02 electrons/photon at 92 eV.

  4. EUV mask making: an approach based on the direct patterning of the EUV reflector

    NASA Astrophysics Data System (ADS)

    Chovino, Christian; Dieu, Laurent; Johnstone, Eric; Reyes, Julio; La Fontaine, Bruno M.; Levinson, Harry J.; Pawloski, Adam R.

    2003-12-01

    Extreme Ultraviolet Lithography (EUVL) is the leading candidate for manufacturing integrated circuits beyond the 45-nm technology node. The masks for EUVL are reflective and significantly different from current transmission masks for deep UV lithography. Many authors have demonstrated the patterning of EUVL masks using different types of absorber stacks that were deposited on top of the multilayer reflector. More recently, a new approach based on the etching of the multilayer reflector in order to define the mask pattern was proposed [2]. Using rigorous electro-magnetic simulations, it was shown that this subtractive approach could provide better process latitude, less H-V bias and smaller image-placement errors compared to the traditional masks based on the additive method. Even though the mask processing shows interesting challenges, this approach might offer immediate advantages over the more traditional patterning technique using the absorber stack, beyond those predicted for lithography imaging. These include the possibility to use optical inspection in transmission mode, which can provide the high-contrast images that are essential for high-sensitivity detection of small defects. In this paper, we present the first results on the patterning of EUVL masks using the direct etching the EUVL multilayer reflector (Mo/Si type) to produce EUV binary masks. In particular, we show how the process parameters can be adjusted to control the pattern sidewall angle. We also present an analysis of the influence of this sidewall angle on lithography imaging, based on lithography simulations. Finally, we show results from the optical inspection of these etched-multilayer binary masks (EMBM).

  5. Coatings on reflective mask substrates

    SciTech Connect

    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.

  6. Mechanisms of Masked Priming: Testing the Entry Opening Model

    ERIC Educational Resources Information Center

    Wu, Hongmei

    2012-01-01

    Since it was introduced in Forster and Davis (1984), masked priming has been widely adopted in the psycholinguistic research on visual word recognition, but there has been little consensus on its actual mechanisms, i.e. how it occurs and how it should be interpreted. This dissertation addresses two different interpretations of masked priming, one…

  7. Mechanisms of Masked Priming: Testing the Entry Opening Model

    ERIC Educational Resources Information Center

    Wu, Hongmei

    2012-01-01

    Since it was introduced in Forster and Davis (1984), masked priming has been widely adopted in the psycholinguistic research on visual word recognition, but there has been little consensus on its actual mechanisms, i.e. how it occurs and how it should be interpreted. This dissertation addresses two different interpretations of masked priming, one…

  8. Near-field diffraction simulation on three-dimensional mask model with off-axis illumination

    NASA Astrophysics Data System (ADS)

    Cheng, Lin; Cao, Peng-fei; Liu, Jia; Zhang, Xiao-ping

    2009-05-01

    In 45nm technology node and beyond with hyper NA and Off-axis Illumination(OAI) lithography simulation, mask topography effect is not ignorable, for calculating near-field distribution based on scalar diffraction theory is insufficient on accuracy. Real three-dimensional (3D) simulation is required for precise evaluation of printing performance and the accuracy of 3D mask model on simulation is a key issue, especially for the mask with contact holes, corners or island patterns, even for 3D defect detection. In this paper, a general 3D mask model on simulation is presented and its near-field diffraction distributions can be described by the thickness of mask, the oblique incident angle, azimuth angle and polarization. Example of simulations are implemented on 3D mask with contact hole without or with optical proximity correction (OPC) assistant patterns, we get the same results as those from rigorous electromagnetic field simulation (REMFS).

  9. Modeling and Observations of Phase-Mask Trapezoidal Profiles with Grating-Fiber Image Reproduction

    NASA Technical Reports Server (NTRS)

    Lyons, Donald R.; Lindesay, James V.; Lee, Hyung R.; Ndlela, Zolili U.; Thompso, Erica J.

    2000-01-01

    We report on an investigation of the trapezoidal design and fabrication defects in phase masks used to produce Bragg reflection gratings in optical fibers. We used a direct visualization technique to examine the nonuniformity of the interference patterns generated by several phase masks. Fringe patterns from the phase masks are compared with the analogous patterns resulting from two-beam interference. Atomic force microscope imaging of the actual phase gratings that give rise to anomalous fringe patterns is used to determine input parameters for a general theoretical model. Phase masks with pitches of 0.566 and 1.059 microns are modeled and investigated.

  10. Actinic review of EUV masks: Status and recent results of the AIMS EUV system

    NASA Astrophysics Data System (ADS)

    Weiss, Markus R.; Hellweg, Dirk; Koch, Markus; Peters, Jan Hendrik; Perlitz, Sascha; Garetto, Anthony; Magnusson, Krister; Capelli, Renzo; Jindal, Vibhu

    2015-03-01

    The EUV mask infrastructure is of key importance for the successful introduction of EUV lithography into volume production. In particular, for the production of defect free masks an actinic review of potential defect sites is required. To realize such an actinic review tool, Carl Zeiss and the SEMATECH EUVL Mask Infrastructure consortium started a development program for an EUV aerial image metrology system, the AIMS™ EUV. In this paper, we discuss the current status of the prototype integration and show recent results.

  11. Actinic review of EUV masks: performance data and status of the AIMS EUV System

    NASA Astrophysics Data System (ADS)

    Hellweg, Dirk; Perlitz, Sascha; Magnusson, Krister; Capelli, Renzo; Koch, Markus; Malloy, Matt

    2016-03-01

    The EUV mask infrastructure is of key importance for the successful introduction of EUV lithography into volume production. In particular, for the production of defect free masks an actinic review of potential defect sites is required. ZEISS and the SUNY POLY SEMATECH EUVL Mask Infrastructure consortium started a development program for such an EUV aerial image metrology system, the AIMS EUV. In this paper, we provide measurement data on the system's key specifications and discuss its performance and capability status.

  12. Shape-dependent dose margin correction using model-based mask data preparation

    NASA Astrophysics Data System (ADS)

    Kimura, Yasuki; Yamamoto, Ryuuji; Kubota, Takao; Kouno, Kenji; Matsushita, Shohei; Hagiwara, Kazuyuki; Hara, Daisuke

    2012-11-01

    Dose Margin has always been known to be a critical factor in mask making. This paper describes why the issue is far more critical than ever before with the 20-nm logic node and beyond using ArF Immersion lithography. Model-Based Mask Data Preparation (MB-MDP) had been presented [references] to show shot count improvements for these complex masks. This paper describes that MBMDP also improves the dose margin. The improvement predicted with theoretical simulation with D2S is confirmed by the results of real mask written by JBX-3200MV (JEOL) by HOYA.

  13. Accurate, full chip 3D electromagnetic field model for non-Manhattan mask corners

    NASA Astrophysics Data System (ADS)

    Lam, Michael; Clifford, Chris; Oliver, Michael; Fryer, David; Tejnil, Edita; Adam, Kostas

    2015-03-01

    The physical process of mask manufacturing produces absorber geometry with significantly less than 90 degree fidelity at corners. The non-Manhattan mask geometry is an essential contributor to the aerial image and resulting patterning performance through focus. Current state of the art models for corner rounding employ "chopping" a 90 degree mask corner, replacing the corner with a small 45 degree edge. In this paper, a methodology is presented to approximate the impact of 3D EMF effects introduced by corners with rounded edges. The approach is integrated into a full chip 3D mask simulation methodology based on the Domain Decomposition Method (DDM) with edge to edge crosstalk correction.

  14. Automated and integrated mask generation from a CAD constructed 3D model.

    SciTech Connect

    Schiek, Richard Louis; Schmidt, Rodney Cannon

    2005-03-01

    We have developed and implemented a method which given a three-dimensional object can infer from topology the two-dimensional masks needed to produce that object with surface micromachining. This design tool calculates the two-dimensional mask set required to produce a given three-dimensional model by investigating the vertical topology to the model. The 3D model is first separated into bodies that are non-intersecting, made from different materials or only linked through a ground plane. Next, for each body unique horizontal cross sections are located and arranged into a tree based on their topological relationship. A branch-wise search of the tree uncovers locations where deposition boundaries must lie and identifies candidate masks creating a generic mask set for the 3D model. Finally, in the last step specific process requirements are considered that may constrain the generic mask set.

  15. A study of defects on EUV mask using blank inspection, patterned mask inspection, and wafer inspection

    SciTech Connect

    Huh, S.; Ren, L.; Chan, D.; Wurm, S.; Goldberg, K. A.; Mochi, I.; Nakajima, T.; Kishimoto, M.; Ahn, B.; Kang, I.; Park, J.-O.; Cho, K.; Han, S.-I.; Laursen, T.

    2010-03-12

    The availability of defect-free masks remains one of the key challenges for inserting extreme ultraviolet lithography (EUVL) into high volume manufacturing. yet link data is available for understanding native defects on real masks. In this paper, a full-field EUV mask is fabricated to investigate the printability of various defects on the mask. The printability of defects and identification of their source from mask fabrication to handling were studied using wafer inspection. The printable blank defect density excluding particles and patterns is 0.63 cm{sup 2}. Mask inspection is shown to have better sensitivity than wafer inspection. The sensitivity of wafer inspection must be improved using through-focus analysis and a different wafer stack.

  16. EXTATIC: ASML's α-tool development for EUVL

    NASA Astrophysics Data System (ADS)

    Meiling, Hans; Benschop, Jos P.; Hartman, Robert A.; Kuerz, Peter; Hoghoj, Peter; Geyl, Roland; Harned, Noreen

    2002-07-01

    Within the recently initiated EXTATIC project a complete full-field lithography exposure tool for he 50-nm technology node is being developed. The goal is to demonstrate the feasibility of extreme UV lithography (EUVL) for 50-nm imaging and to reduce technological risks in the development of EUVL production tools. We describe the EUV MEDEA+) framework in which EXTATIC is executed, and give an update on the status of the (alpha) -tool development. A brief summary of our in-house source-collector module development is given, as well as the general vacuum architecture of the (alpha) -tool is discussed. We discuss defect-free reticle handling, and investigated the uses of V-grooved brackets glued to the side of the reticle to reduce particle generation during takeovers. These takeovers do not only occur in the exposure tool, but also in multilayer deposition equipment, e-beam pattern writers, inspection tools, etc., where similar requirements on particle contamination are present. Finally, we present an update of mirror fabrication technology and show improved mirror figuring and finishing results.

  17. Design and fabrication considerations of EUVL collectors for HVM

    NASA Astrophysics Data System (ADS)

    Bianucci, G.; Cassol, G. L.; Kools, J.; Prea, M.; Salmaso, G.; Valsecchi, G.; Zocchi, F. E.; Bolshukhin, D.; Schürmann, M.; Schriever, G.; Mader, A.; Zink, P.

    2009-03-01

    The power roadmap for EUVL high volume manufacturing (HVM) exceeds the 200W EUV in-band power at intermediate focus, thus posing more demanding requirements on HVM sources, debris suppression systems and collectors. Starting from the lessons learned in the design and fabrication of the grazing incidence collectors for the Alpha EUVL scanners, Media Lario Technologies is developing HVM optical solutions that enable designed-in lifetime improvements, such as larger source-collector distances, optimized collection efficiency through larger collected solid angles, and customized EUV reflective layers. The optical design of an HVM collector is described together with the selection of the sacrificial ruthenium reflective layer. The water cooling layout of the collector is evolved from the integrated cooling technology developed at Alpha level into an innovative cooling layout that minimizes the thermal gradients across the mirrors and allows controlling the optical performance at the far-field plane. Finally, the evolution of the collector's manufacturing technologies for HVM is discussed. XTREME technologies and Philips Extreme UV support this work by integrating the collector in the complete source collector module (SoCoMo). At system level, each component of the SoCoMo is part of a development and improvement plan leading to a comprehensive system that will fulfill the 200+ W EUV in-band power at intermediate focus.

  18. Efficient full-chip mask 3D model for off-axis illumination

    NASA Astrophysics Data System (ADS)

    Zhang, Hongbo; Yan, Qiliang; Zhang, Lin; Croffie, Ebo; Brooker, Peter; Ren, Qian; Fan, Yongfa

    2013-09-01

    Mask topography (Mask3D) effect is one of the most influential factors in sub-28 nm technology node. To build a successful Mask3D compact model, the runtime efficiency, accuracy and the flexibility to handle various geometry patterns are the three most important criterion to fulfill. In the meanwhile, Mask3D modeling must be able to handle the off-axis illumination (OAI) condition accurately. In this paper, we propose our full chip Mask3D modeling method which is an extension to the edge-based Mask3D model. In our modeling flow, we first review the edge-based Mask3D model and then analyze the impact from the off-axis source. We propose a parameter-based extension to characterize the off-axis impact efficiently. We further introduce two methods to calibrate the OAI-aware parameters by using rigorous or wafer data as the reference. Our experimental results show the great calibration accuracy throughout the defocus range with OAI sources, and validate the accuracy of our two parameter calibration approach.

  19. Accurate, full-chip, three-dimensional electromagnetic field model for non-Manhattan mask corners

    NASA Astrophysics Data System (ADS)

    Lam, Michael C.; Clifford, Chris; Oliver, Mike; Fryer, David; Tejnil, Edita; Adam, Kostas

    2016-04-01

    The physical process of mask manufacturing produces absorber geometry with significant deviations from the 90-deg corners, which are typically assumed in the mask design. The non-Manhattan mask geometry is an essential contributor to the aerial image and resulting patterning performance through focus. Current state-of-the-art models for corner rounding employ "chopping" a 90-deg mask corner, replacing the corner with a small 45-deg edge. A methodology is presented to approximate the impact of three-dimensional (3-D) EMF effects introduced by corners with rounded edges. The approach is integrated into a full-chip 3-D mask simulation methodology based on the domain decomposition method with edge to edge crosstalk correction.

  20. Masked Translation Priming with Semantic Categorization: Testing the Sense Model

    ERIC Educational Resources Information Center

    Wang, Xin; Forster, Kenneth I.

    2010-01-01

    Four experiments are reported which were designed to test hypotheses concerning the asymmetry of masked translation priming. Experiment 1 confirmed the presence of L2-L1 priming with a semantic categorization task and demonstrated that this effect was restricted to exemplars. Experiment 2 showed that the translation priming effect was not due to…

  1. Masked Translation Priming with Semantic Categorization: Testing the Sense Model

    ERIC Educational Resources Information Center

    Wang, Xin; Forster, Kenneth I.

    2010-01-01

    Four experiments are reported which were designed to test hypotheses concerning the asymmetry of masked translation priming. Experiment 1 confirmed the presence of L2-L1 priming with a semantic categorization task and demonstrated that this effect was restricted to exemplars. Experiment 2 showed that the translation priming effect was not due to…

  2. Top Level User Specifications for Mask Inspection Microscope

    SciTech Connect

    Barty, A; Taylor, J S

    2002-01-31

    This document compiles top-level user specifications for an EUV microscope for characterizing EUVL mask defects. Two broad categories of application are considered: (1) emulation of the imaging characteristics of a stepper for printability analysis (AIM mode); and (2) high-resolution imaging for obtaining a more detailed characterization of defects or mask features. It is generally assumed that the mask defects that are to be characterized have been located by a previous inspection procedure and the spatial coordinates of the defect can be transferred to the microscope.

  3. Mask process simulation for mask quality improvement

    NASA Astrophysics Data System (ADS)

    Takahashi, Nobuyasu; Goto, So; Tsunoda, Dai; Shin, So-Eun; Lee, Sukho; Shon, Jungwook; Park, Jisoong

    2015-10-01

    Demand for mask process correction (MPC) is growing facing the 14nm era. We have developed model based MPC and can generate mask contours by using this mask process model. This mask process model consists of EB (development) and etch, which employs a threshold (level set) model and a variable bias model respectively. The model calibration tool accepts both CD measurement results and SEM images. The simulation can generate mask image (contour), runs with distributed computing resources, and has scalable performance. The contour simulation shows the accuracy of the MPC correction visually and provides comprehensive information about hot spots in mask fabrication. Additionally, it is possible to improve lithography simulation quality by providing a simulated mask contour. In this paper, accuracy and computational performance of mask process simulation are shown. The focus is on the difference between the calibration methods using CDs or images.

  4. 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.

  5. Sensitivity-Limiting Factors of at-Wavelength Extreme Ultraviolet Lithography Mask Blank Inspection

    NASA Astrophysics Data System (ADS)

    Tezuka, Yoshihiro; Tanaka, Toshihiko; Terasawa, Tsuneo; Tomie, Toshihisa

    2006-06-01

    Sensitivity-limiting factors of at-wavelength inspection for extreme UV lithography (EUVL) mask blanks have been analyzed. The sensitivity of the inspection tool is modeled on the basis of the inspection image of programmed multilayer defects and the characterized attributes of the tool components. The characterization includes point spread function (PSF) analysis of the imaging optics and the back-illuminated charge-coupled-device (BI-CCD) sensor as well as power spectral density (PSD) analysis of the mask blank surface. The statistical scaling of signal-to-noise ratio (SNR) in conjunction with the variables of optics, sensors, and mask blanks has predicted effective improvement paths of its sensitivity. Increasing the magnification of optics, reducing the total PSF, and improving the roughness of mask blanks will address the needs for its application in future generations. Signal intensity dependency on the geometrical attributes of defects is also studied by both experiment and electromagnetic simulation. It is revealed that the bottom height of defects and defect smoothing throughout the multilayer deposition significantly influence defect signal intensity. Comprehensive measures to accommodate a variety of defects and to mitigate associated risks are also discussed.

  6. An engineered design of a diffractive mask for high precision astrometry [Modeling a diffractive mask that calibrates optical distortions

    DOE PAGES

    Dennison, Kaitlin; Ammons, S. Mark; Garrel, Vincent; ...

    2016-06-26

    AutoCAD, Zemax Optic Studio 15, and Interactive Data Language (IDL) with the Proper Library are used to computationally model and test a diffractive mask (DiM) suitable for use in the Gemini Multi-Conjugate Adaptive Optics System (GeMS) on the Gemini South Telescope. Systematic errors in telescope imagery are produced when the light travels through the adaptive optics system of the telescope. DiM is a transparent, flat optic with a pattern of miniscule dots lithographically applied to it. It is added ahead of the adaptive optics system in the telescope in order to produce diffraction spots that will encode systematic errors inmore » the optics after it. Once these errors are encoded, they can be corrected for. DiM will allow for more accurate measurements in astrometry and thus improve exoplanet detection. Furthermore, the mechanics and physical attributes of the DiM are modeled in AutoCAD. Zemax models the ray propagation of point sources of light through the telescope. IDL and Proper simulate the wavefront and image results of the telescope. Aberrations are added to the Zemax and IDL models to test how the diffraction spots from the DiM change in the final images. Based on the Zemax and IDL results, the diffraction spots are able to encode the systematic aberrations.« less

  7. An engineered design of a diffractive mask for high precision astrometry [Modeling a diffractive mask that calibrates optical distortions

    SciTech Connect

    Dennison, Kaitlin; Ammons, S. Mark; Garrel, Vincent; Marin, Eduardo; Sivo, Gaetano; Bendek, Eduardo; Guyon, Oliver

    2016-06-26

    AutoCAD, Zemax Optic Studio 15, and Interactive Data Language (IDL) with the Proper Library are used to computationally model and test a diffractive mask (DiM) suitable for use in the Gemini Multi-Conjugate Adaptive Optics System (GeMS) on the Gemini South Telescope. Systematic errors in telescope imagery are produced when the light travels through the adaptive optics system of the telescope. DiM is a transparent, flat optic with a pattern of miniscule dots lithographically applied to it. It is added ahead of the adaptive optics system in the telescope in order to produce diffraction spots that will encode systematic errors in the optics after it. Once these errors are encoded, they can be corrected for. DiM will allow for more accurate measurements in astrometry and thus improve exoplanet detection. Furthermore, the mechanics and physical attributes of the DiM are modeled in AutoCAD. Zemax models the ray propagation of point sources of light through the telescope. IDL and Proper simulate the wavefront and image results of the telescope. Aberrations are added to the Zemax and IDL models to test how the diffraction spots from the DiM change in the final images. Based on the Zemax and IDL results, the diffraction spots are able to encode the systematic aberrations.

  8. An engineered design of a diffractive mask for high precision astrometry [Modeling a diffractive mask that calibrates optical distortions

    SciTech Connect

    Dennison, Kaitlin; Ammons, S. Mark; Garrel, Vincent; Marin, Eduardo; Sivo, Gaetano; Bendek, Eduardo; Guyon, Oliver

    2016-06-26

    AutoCAD, Zemax Optic Studio 15, and Interactive Data Language (IDL) with the Proper Library are used to computationally model and test a diffractive mask (DiM) suitable for use in the Gemini Multi-Conjugate Adaptive Optics System (GeMS) on the Gemini South Telescope. Systematic errors in telescope imagery are produced when the light travels through the adaptive optics system of the telescope. DiM is a transparent, flat optic with a pattern of miniscule dots lithographically applied to it. It is added ahead of the adaptive optics system in the telescope in order to produce diffraction spots that will encode systematic errors in the optics after it. Once these errors are encoded, they can be corrected for. DiM will allow for more accurate measurements in astrometry and thus improve exoplanet detection. Furthermore, the mechanics and physical attributes of the DiM are modeled in AutoCAD. Zemax models the ray propagation of point sources of light through the telescope. IDL and Proper simulate the wavefront and image results of the telescope. Aberrations are added to the Zemax and IDL models to test how the diffraction spots from the DiM change in the final images. Based on the Zemax and IDL results, the diffraction spots are able to encode the systematic aberrations.

  9. Optimization of mask manufacturing rule check constraint for model based assist feature generation

    NASA Astrophysics Data System (ADS)

    Shim, Seongbo; Kim, Young-chang; Chun, Yong-jin; Lee, Seong-Woo; Lee, Suk-joo; Choi, Seong-woon; Han, Woo-sung; Chang, Seong-hoon; Yoon, Seok-chan; Kim, Hee-bom; Ki, Won-tai; Woo, Sang-gyun; Cho, Han-gu

    2008-11-01

    space restriction. The test mask for this experimental work includes not only typical split patterns but also real device patterns that are generated by in-house model-based assist feature generation tool. We analyzed the mask writing result for typical patterns and compared the simulation result, and wafer result for real device patterns.

  10. Evaluation of the Basic Airway Model, a novel mask ventilation training manikin.

    PubMed

    Sudhir, G; Stacey, M R W; Hampson, M; Mecklenburgh, J

    2007-09-01

    The Basic Airway Model is an airway manikin designed for training in mask ventilation. We investigated the ability of the Basic Airway Model to provide varying levels of difficulty for mask ventilation. Volunteers with three levels of experience (novice, intermediate and expert) attempted to ventilate the manikin at three levels of difficulty: easy, intermediate and difficult. The distribution of frequencies of successful ventilation by different groups at the three levels of difficulty were statistically significant (p < 0.0001). The median (IQR (range)) degree of difficulty was 3 (2-5 (1-7)), 4 (3-5.3 (2-7)) and 6 (5-7 (3-9)) for easy, intermediate and difficult settings, respectively. We conclude that the Basic Airway Model can provide different levels of difficulty for mask ventilation training.

  11. A non-delta-chrome OPC methodology for process models with three-dimensional mask effects

    NASA Astrophysics Data System (ADS)

    Ng, Philip C. W.; Tsai, Kuen-Yu; Tang, Chih-Hsien; Melvin, Lawrence

    2010-04-01

    Delta-chrome optical proximity correction (OPC) has been widely adopted in lithographic patterning for semiconductor manufacturing. During the delta-chrome OPC iteration, a predetermined amount of chrome is added or subtracted from the mask pattern. With this chrome change, the change of exposure intensity error (IE) or the change of edge placement error (EPE) between the printed contour and the target pattern is then calculated based on standard Kirchhoff approximation. Linear approximation is used to predict the amount of the proper chrome change to remove the correction error. This approximation can be very fast and effective, but must be performed iteratively to capture interactions between chrome changes. As integrated circuit (IC) design shrinks to the deep sub-wavelength regime, previously ignored nonlinear process effects, such as three-dimensional (3D) mask effects and resist development effects, become significant for accurate prediction and correction of proximity effects. These nonlinearities challenge the deltachrome OPC methodology. The model response to mask pattern perturbation by linear approximation can be readily computed but inaccurate. In fact, computation of the mask perturbation response becomes complex and expensive. A non-delta-chrome OPC methodology with IE-based feedback compensation is proposed. It determines the amount of the proper chrome change based on IE without intensive computation of mask perturbation response. Its effectiveness in improving patterning fidelity and runtime is examined on a 50-nm practical circuit layout. Despite the presence and the absence of nonlinear 3D mask effects, our results show the proposed non-delta-chrome OPC outperforms the deltachrome one in terms of patterning fidelity and runtime. The results also demonstrate that process models with 3D mask effects limit the use of delta-chrome OPC methodology.

  12. Fabrication and Modeling of the Gray-Scale Mask Based Aspheric Refraction Microlens Array

    NASA Astrophysics Data System (ADS)

    Wang, Gou-Jen; Wang, Shuh-Yi; Chin, Chi-Hsian

    In this research, the manufacturing processes of aspherical refraction microlens array by gray-scale mask if investigated. In the first part of this research, we emphasize on the gray-scale mask based microlens array fabrication processes through the UV-LIGA approach. Furthermore, a two-stage process-modeling scheme is proposed to reduce the time-consuming trail-and-error parameters tuning labor works. Experimental results demonstrate that the proposed approach can well model the fabrication process and is capable of providing effective fabrication parameters once the diameter and height of a certain microlens is provided.

  13. Considering mask pellicle effect for more accurate OPC model at 45nm technology node

    NASA Astrophysics Data System (ADS)

    Wang, Ching-Heng; Liu, Qingwei; Zhang, Liguo

    2008-11-01

    Now it comes to the 45nm technology node, which should be the first generation of the immersion micro-lithography. And the brand-new lithography tool makes many optical effects, which can be ignored at 90nm and 65nm nodes, now have significant impact on the pattern transmission process from design to silicon. Among all the effects, one that needs to be pay attention to is the mask pellicle effect's impact on the critical dimension variation. With the implement of hyper-NA lithography tools, light transmits the mask pellicle vertically is not a good approximation now, and the image blurring induced by the mask pellicle should be taken into account in the computational microlithography. In this works, we investigate how the mask pellicle impacts the accuracy of the OPC model. And we will show that considering the extremely tight critical dimension control spec for 45nm generation node, to take the mask pellicle effect into the OPC model now becomes necessary.

  14. 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.

  15. Enhanced defect detection capability using learning system for extreme ultraviolet lithography mask inspection tool with projection electron microscope optics

    NASA Astrophysics Data System (ADS)

    Hirano, Ryoichi; Hatakeyama, Masahiro; Terao, Kenji; Watanabe, Hidehiro

    2016-04-01

    Extreme ultraviolet lithography (EUVL) patterned mask defect detection is a major issue that must be addressed to realize EUVL-based device fabrication. We have designed projection electron microscope (PEM) optics for integration into a mask inspection system, and the resulting PEM system performs well in half-pitch (hp) 16-nm-node EUVL patterned mask inspection applications. A learning system has been used in this PEM patterned mask inspection tool. The PEM identifies defects using the "defectivity" parameter that is derived from the acquired image characteristics. The learning system has been developed to reduce the labor and the costs associated with adjustment of the PEM's detection capabilities to cope with newly defined mask defects. The concepts behind this learning system and the parameter optimization flow are presented here. The learning system for the PEM is based on a library of registered defects. The learning system then optimizes the detection capability by reconciling previously registered defects with newly registered defects. Functional verification of the learning system is also described, and the system's detection capability is demonstrated by applying it to the inspection of hp 11-nm EUV masks. We can thus provide a user-friendly mask inspection system with reduced cost of ownership.

  16. Determining the critical size of EUV mask substrate defects

    SciTech Connect

    Goldberg, Kenneth A.; Gullikson, Eric M.; Han, Hakseung; Cho, Wonil; Jeon, Chan-Uk; Wurm, Stefan

    2008-05-26

    Determining the printability of substrate defects beneath the extreme ultraviolet (EUV) reflecting multilayer stack is an important issue in EUVL lithography. Several simulation studies have been performed in the past to determine the tolerable defect size on EUV mask blank substrates but the industry still has no exact specification based on real printability tests. Therefore, it is imperative to experimentally determine the printability of small defects on a mask blanks that are caused by substrate defects using direct printing of programmed substrate defect in an EUV exposure tools. SEMATECH fabricated bump type program defect masks using standard electron beam lithography and performed printing tests with the masks using an EUV exposure tool. Defect images were also captured using SEMATECH's Berkeley Actinic Imaging Tool in order to compare aerial defect images with secondary electron microscope images from exposed wafers. In this paper, a comprehensive understanding of substrate defect printability will be presented and printability specifications of EUV mask substrate defects will be discussed.

  17. Determining the Critcial Size of EUV Mask Substrate Defects

    SciTech Connect

    Mccall, Monnikue M; Han, Hakseung; Cho, Wonil; Goldberg, Kenneth; Gullikson, Eric; Jeon, Chan-Uk; Wurm, Stefan

    2008-02-28

    Determining the printability of substrate defects beneath the extreme ultraviolet (EUV) reflecting multilayer stack is an important issue in EUVL lithography. Several simulation studies have been performed in the past to determine the tolerable defect size on EUV mask blank substrates but the industry still has no exact specification based on real printability tests. Therefore, it is imperative to experimentally determine the printability of small defects on a mask blanks that are caused by substrate defects using direct printing of programmed substrate defect in an EUV exposure tool. SEMATECH fabricated bump type program defect masks using standard electron beam lithography and performed printing tests with the masks using an EUV exposure tool. Defect images were also captured using SEMATECH's Berkeley Actinic Imaging Tool in order to compare aerial defect images with secondary electron microscope images from exposed wafers. In this paper, a comprehensive understanding of substrate defect printability will be presented and printability specifications of EUV mask substrate defects will be discussed.

  18. Application of artificial neural networks to compact mask models in optical lithography simulation

    NASA Astrophysics Data System (ADS)

    Agudelo, Viviana; Fühner, Tim; Erdmann, Andreas; Evanschitzky, Peter

    2013-04-01

    Compact mask models provide an alternative to speed up rigorous mask diffraction computation based on electromagnetic field (EMF) modeling. The high time expense of the rigorous mask models in the simulation process challenges the exploration of innovative modeling techniques to compromise accuracy and speed in the computation of the diffracted field and vectorial imaging in optical lithographic systems. The Artificial Neural Network (ANN) approach is presented as an alternative to retrieve the spectrum of the mask layout in an accurate yet efficient way. The validity of the ANN for different illuminations, feature sizes, pitches and shapes is investigated. The evaluation of the performance of this approach is performed by a process windows analysis, comparison of the spectra, best focus and critical dimension (CD) through pitch. The application of various layouts demonstrated that the ANN can also be trained with different patterns to reproduce various effects such as: shift of the line position, different linewidths and line ends. Comparisons of the ANN approach with other compact models such as boundary layer model, pulses modification, spectrum correction and pupil filtering techniques are presented.

  19. Model-based mask data preparation (MB-MDP) and its impact on resist heating

    NASA Astrophysics Data System (ADS)

    Fujimura, Aki; Kamikubo, Takashi; Bork, Ingo

    2011-04-01

    Complex mask shapes will be required on critical layer masks for 20nm logic node, threatening to explode the mask write times. Model-Based Mask Data Preparation (MB-MDP) has been introduced to reduce the shot count required to write complex masks while simultaneously improving resolution and dose margin of sub-100nm features. For production use of MB-MDP, a number of questions have been raised and answered. This paper summarizes these potential issues and their resolutions. In particular, the paper takes an in-depth look at one of the questions: impact of overlapping shots on heating effect. The paper concludes that while heating effect is an important issue for all e-beam writing even with conventional non-overlapping shots, overall dose density per unit time over microns of space is the principal driver behind heating effects. Highly local shot density and shot sequencing does not affect heating significantly, particularly for smaller shots. MB-MDP does not introduce any additional concerns.

  20. Growth and Printability of Multilayer Phase Defects on EUV MaskBlanks

    SciTech Connect

    Liang, Ted; Ultanir, Erdem; Zhnag, Guojing; Park, Seh-Jin; Anderson, Erik; Gullikson, Eric; Naulleau, Patrick; Salmassi, Farhad; Mirkarimi, Paul; Spiller, Eberhard; Baker, Sherry

    2007-06-10

    The ability to fabricate defect-free mask blanks is a well-recognized challenge in enabling extreme ultraviolet lithography (EUVL) for semiconductor manufacturing. Both the specification and reduction of defects necessitate the understanding of their printability and how they are generated and grow during Mo-Si multilayer (ML) deposition. A ML phase defect can be depicted by its topographical profile on the surface as either a bump or pit, which is then characterized by height or depth and width. The complexity of such seemingly simple phase defects lies in the many ways they can be generated and the difficulties of measuring their physical shape/size and optical effects on printability. An effective way to study phase defects is to use a programmed defect mask (PDM) as 'model' test sample where the defects are produced with controlled growth on a ML blank and accurate placement in varying proximity to absorber patterns on the mask. This paper describes our recent study of ML phase defect printability with resist data from exposures of a ML PDM on the EUV micro-exposure tool (MET, 5X reduction with 0.3NA).

  1. Mask optimization approaches in optical lithography based on a vector imaging model.

    PubMed

    Ma, Xu; Li, Yanqiu; Dong, Lisong

    2012-07-01

    Recently, a set of gradient-based optical proximity correction (OPC) and phase-shifting mask (PSM) optimization methods has been developed to solve for the inverse lithography problem under scalar imaging models, which are only accurate for numerical apertures (NAs) of less than approximately 0.4. However, as lithography technology enters the 45 nm realm, immersion lithography systems with hyper-NA (NA>1) are now extensively used in the semiconductor industry. For the hyper-NA lithography systems, the vector nature of the electromagnetic field must be taken into account, leading to the vector imaging models. Thus, the OPC and PSM optimization approaches developed under the scalar imaging models are inadequate to enhance the resolution in immersion lithography systems. This paper focuses on developing pixelated gradient-based OPC and PSM optimization algorithms under a vector imaging model. We first formulate the mask optimization framework, in which the imaging process of the optical lithography system is represented by an integrative and analytic vector imaging model. A gradient-based algorithm is then used to optimize the mask iteratively. Subsequently, a generalized wavelet penalty is proposed to keep a balance between the mask complexity and convergence errors. Finally, a set of methods is exploited to speed up the proposed algorithms.

  2. Mathematical modeling of pattern formation caused by drying of colloidal film under a mask.

    PubMed

    Tarasevich, Yuri Yu; Vodolazskaya, Irina V; Sakharova, Lyudmila V

    2016-02-01

    In our model, we simulate an experiment (D.J. Harris, H. Hu, J.C. Conrad, J.A. Lewis, Patterning colloidal films via evaporative lithography, Phys. Rev. Lett. 98, 148301 (2007)). A thin colloidal sessile droplet is allowed to dry out on a horizontal hydrophilic surface. A mask just above the droplet predominantly allows evaporation from the droplet free surface directly beneath the holes in the mask. We consider one special case, when the holes in the mask are arranged so that the system has rotational symmetry of order m . We use a speculative evaporative flux to mimic the real system. Advection, diffusion, and sedimentation are taken into account. FlexPDE is utilized to solve an advection-diffusion equation using the finite element method. The simulation demonstrates that the colloidal particles accumulate below the holes as the solvent evaporates. Diffusion can reduce this accumulation.

  3. Properites of ultrathin films appropriate for optics capping layers in extreme ultraviolet lithography (EUVL)

    SciTech Connect

    Bajt, S; Edwards, N V; Madey, T E

    2007-06-25

    The contamination of optical surfaces by irradiation shortens optics lifetime and is one of the main concerns for optics used in conjunction with intense light sources, such as high power lasers, 3rd and 4th generation synchrotron sources or plasma sources used in extreme ultraviolet lithography (EUVL) tools. This paper focuses on properties and surface chemistry of different materials, which as thin layers, could be used as capping layers to protect and extend EUVL optics lifetime. The most promising candidates include single element materials such as ruthenium and rhodium, and oxides such as TiO{sub 2} and ZrO{sub 2}.

  4. Reflective masks for extreme ultraviolet lithography

    SciTech Connect

    Nguyen, Khanh Bao

    1994-05-01

    Extreme ultraviolet lithographic masks are made by patterning multilayer reflective coatings with high normal incidence reflectivity. Masks can be patterned by depositing a patterned absorber layer above the coating or by etching the pattern directly into the coating itself. Electromagnetic simulations showed that absorber-overlayer masks have superior imaging characteristics over etched masks (less sensitive to incident angles and pattern profiles). In an EUVL absorber overlayer mask, defects can occur in the mask substrate, reflective coating, and absorber pattern. Electromagnetic simulations showed that substrate defects cause the most severe image degradation. A printability study of substrate defects for absorber overlayer masks showed that printability of 25 nm high substrate defects are comparable to defects in optical lithography. Simulations also indicated that the manner in which the defects are covered by multilayer reflective coatings can affect printability. Coverage profiles that result in large lateral spreading of defect geometries amplify the printability of the defects by increasing their effective sizes. Coverage profiles of Mo/Si coatings deposited above defects were studied by atomic force microscopy and TEM. Results showed that lateral spread of defect geometry is proportional to height. Undercut at defect also increases the lateral spread. Reductions in defect heights were observed for 0.15 μm wide defect lines. A long-term study of Mo/Si coating reflectivity revealed that Mo/Si coatings with Mo as the top layer suffer significant reductions in reflectivity over time due to oxidation.

  5. Novel EUV Mask Blank Defect Repair Developments

    SciTech Connect

    Hau-Riege, S; Barty, A; Mirkarimi, P

    2003-03-31

    The development of defect-free reticle blanks is an important challenge facing the commercialization of extreme ultraviolet lithography (EUVL). The basis of EUVL reticles are mask blanks consisting of a substrate and a reflective Mo/Si multilayer. Defects on the substrate or defects introduced during multilayer deposition can result in critical phase and amplitude defects. Amplitude- or phase-defect repair techniques are being developed with the goal to repair many of these defects. In this report, we discuss progress in two areas of defect repair: (1) We discuss the effect of the residual reflectance variation over the repair zone after amplitude-defect repair on the process window. This allows the determination of the maximum tolerable residual damage induced by amplitude defect repair. (2) We further performed a quantitative assessment of the yield improvement due to defect repair. We found that amplitude- and phase-defect repair have the potential to significantly improve mask blank yield. Our calculations further show that yield can be maximized by increasing the number of Mo/Si bilayers.

  6. Compensation of flare-induced CD changes EUVL

    DOEpatents

    Bjorkholm, John E.; Stearns, Daniel G.; Gullikson, Eric M.; Tichenor, Daniel A.; Hector, Scott D.

    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.

  7. Fabrication and modeling of the gray-scale mask-based aspheric refraction microlens array

    NASA Astrophysics Data System (ADS)

    Wang, Gou-Jen; Wang, Shuh-Yi; Chin, Chi-Hsian

    2002-04-01

    In this research, the manufacturing processes of non- spherical refraction microles array by gray-scale mask is investigated. Compared to the conventional multi-lithography fabricating method, the gray-scale mask approach requires only a single lithography action to fabricate a non- spherical refraction microlens array. In the firs part of this research, we emphasize the gray-scale mask based microlens array fabrication processes through the UV-LIGA approach. Furthermore, a two-stage process-modeling scheme is proposed to reduce the time-consuming trial-and-error parameters tuning labor works. At the first stage, a multi- layer feedforward neural-network is employed to model the relationships between the diameter and height of the microlens are obtained, the surface profile of this microlens can be predicted by an empirical equation. The empirical equation is derived through the regressing analysis method with data points sampled from the real microlens surface profile. Experimental results demonstrate that the proposed two-stage scheme can precisely predict the surface profile of the gray-scale mask based microlens.

  8. Phase defect mitigation strategy: fiducial mark requirements on extreme ultraviolet lithography mask

    NASA Astrophysics Data System (ADS)

    Murachi, Tetsunori; Amano, Tsuyoshi; Oh, Sung Hyun

    2012-03-01

    For Extreme Ultra-Violet Lithography (EUVL), fabrication of defect free multi-layered (ML) mask blanks is one of the difficult challenges. ML defects come from substrate defects and adders during ML coating, cannot be removed, and are called as phase defect. If we can accept ML blanks with certain number of phase defects, the blank yield will be drastically up. In order to use such blanks, the phase defects need to be identified and located during ML blank defect inspection before absorber patterning. To locate phase defects on the blanks accurately and precisely, Fiducial Marks (FM) on ML blanks are needed for mask alignment and defect location information. The proposed requirement of defect location accuracy is <=20 nm [1]. In this paper, we will present the result of feasibility study on the requirements of FM on EUVL mask by simulations & experiments to establish the phase defect mitigation method with EUV Actinic Blank Inspection (ABI) tool. And the optimum ranges of FM line width, depth, and fabrication method on EUVL mask based on above results are >= 5 um line width, >= 100 nm depth FM etched into ML respectively, and additional finer FMs for magnified optics.

  9. Optimized qualification protocol on particle cleanliness for EUV mask infrastructure

    NASA Astrophysics Data System (ADS)

    van der Donck, J. C. J.; Stortelder, J. K.; Derksen, G. B.

    2011-11-01

    With the market introduction of the NXE:3100, Extreme Ultra Violet Lithography (EUVL) enters a new stage. Now infrastructure in the wafer fabs must be prepared for new processes and new materials. Especially the infrastructure for masks poses a challenge. Because of the absence of a pellicle reticle front sides are exceptionally vulnerable to particles. It was also shown that particles on the backside of a reticle may cause tool down time. These effects set extreme requirements to the cleanliness level of the fab infrastructure for EUV masks. The cost of EUV masks justifies the use of equipment that is qualified on particle cleanliness. Until now equipment qualification on particle cleanliness have not been carried out with statistically based qualification procedures. Since we are dealing with extreme clean equipment the number of observed particles is expected to be very low. These particle levels can only be measured by repetitively cycling a mask substrate in the equipment. Recent work in the EUV AD-tool presents data on added particles during load/unload cycles, reported as number of Particles per Reticle Pass (PRP). In the interpretation of the data, variation by deposition statistics is not taken into account. In measurements with low numbers of added particles the standard deviation in PRP number can be large. An additional issue is that particles which are added in the routing outside the equipment may have a large impact on the testing result. The number mismatch between a single handling step outside the tool and the multiple cycling in the equipment makes accuracy of measurements rather complex. The low number of expected particles, the large variation in results and the combined effect of added particles inside and outside the equipment justifies putting good effort in making a test plan. Without a proper statistical background, tests may not be suitable for proving that equipment qualifies for the limiting cleanliness levels. Other risks are that a

  10. Computational Model for Liquid Phase Electro-Epitaxial Crystal Growth on Partially Masked Substrate

    NASA Astrophysics Data System (ADS)

    Khenner, Mikhail; Braun, Richard J.

    2003-03-01

    A computational model for semiconductor crystal growth on a partially masked substrate under simplified LPEE conditions is developed. The model assumes isothermal diffusional growth from molten metal solution, which is enhanced by applied DC current through crystal/melt interface. Finite-difference, front-tracking method is used to numerically evolve the interface according to the set of governing partial differential equations and boundary conditions. Computed examples show strong influence of the electromigration on growth rates in vertical and lateral directions and the dependence of growth on electrical conductivities of substrate and mask materials as well as on wetting contact angle. The study presented is the first attempt to model LPEE growth on patterned substrates commonly employed in semiconductor industry.

  11. Simulated masking of right whale sounds by shipping noise: incorporating a model of the auditory periphery.

    PubMed

    Cunningham, Kane A; Mountain, David C

    2014-03-01

    Many species of large, mysticete whales are known to produce low-frequency communication sounds. These low-frequency sounds are susceptible to communication masking by shipping noise, which also tends to be low frequency in nature. The size of these species makes behavioral assessment of auditory capabilities in controlled, captive environments nearly impossible, and field-based playback experiments are expensive and necessarily limited in scope. Hence, it is desirable to produce a masking model for these species that can aid in determining the potential effects of shipping and other anthropogenic noises on these protected animals. The aim of this study was to build a model that combines a sophisticated representation of the auditory periphery with a spectrogram-based decision stage to predict masking levels. The output of this model can then be combined with a habitat-appropriate propagation model to calculate the potential effects of noise on communication range. For this study, the model was tested on three common North Atlantic right whale communication sounds, both to demonstrate the method and to probe how shipping noise affects the detection of sounds with varying spectral and temporal characteristics.

  12. Theoretical modeling of masking DNA application in aptamer-facilitated biomarker discovery.

    PubMed

    Cherney, Leonid T; Obrecht, Natalia M; Krylov, Sergey N

    2013-04-16

    In aptamer-facilitated biomarker discovery (AptaBiD), aptamers are selected from a library of random DNA (or RNA) sequences for their ability to specifically bind cell-surface biomarkers. The library is incubated with intact cells, and cell-bound DNA molecules are separated from those unbound and amplified by the polymerase chain reaction (PCR). The partitioning/amplification cycle is repeated multiple times while alternating target cells and control cells. Efficient aptamer selection in AptaBiD relies on the inclusion of masking DNA within the cell and library mixture. Masking DNA lacks primer regions for PCR amplification and is typically taken in excess to the library. The role of masking DNA within the selection mixture is to outcompete any nonspecific binding sequences within the initial library, thus allowing specific DNA sequences (i.e., aptamers) to be selected more efficiently. Efficient AptaBiD requires an optimum ratio of masking DNA to library DNA, at which aptamers still bind specific binding sites but nonaptamers within the library do not bind nonspecific binding sites. Here, we have developed a mathematical model that describes the binding processes taking place within the equilibrium mixture of masking DNA, library DNA, and target cells. An obtained mathematical solution allows one to estimate the concentration of masking DNA that is required to outcompete the library DNA at a desirable ratio of bound masking DNA to bound library DNA. The required concentration depends on concentrations of the library and cells as well as on unknown cell characteristics. These characteristics include the concentration of total binding sites on the cell surface, N, and equilibrium dissociation constants, K(nsL) and K(nsM), for nonspecific binding of the library DNA and masking DNA, respectively. We developed a theory that allows the determination of N, K(nsL), and K(nsM) based on measurements of EC50 values for cells mixed separately with the library and masking DNA

  13. Rapid modelling of the redshift-space power spectrum multipoles for a masked density field

    NASA Astrophysics Data System (ADS)

    Wilson, M. J.; Peacock, J. A.; Taylor, A. N.; de la Torre, S.

    2017-01-01

    In this work, we reformulate the forward modelling of the redshift-space power spectrum multipole moments for a masked density field, as encountered in galaxy redshift surveys. Exploiting the symmetries of the redshift-space correlation function, we provide a masked-field generalization of the Hankel transform relation between the multipole moments in real and Fourier space. Using this result, we detail how a likelihood analysis requiring computation for a broad range of desired P(k) models may be executed 103-104 times faster than with other common approaches, together with significant gains in spectral resolution. We present a concrete application to the complex angular geometry of the VIMOS Public Extragalactic Redshift Survey PDR-1 release and discuss the validity of this technique for finite-angle surveys.

  14. Method for characterizing mask defects using image reconstruction from X-ray diffraction patterns

    DOEpatents

    Hau-Riege, Stefan Peter

    2007-05-01

    The invention applies techniques for image reconstruction from X-ray diffraction patterns on the three-dimensional imaging of defects in EUVL multilayer films. The reconstructed image gives information about the out-of-plane position and the diffraction strength of the defect. The positional information can be used to select the correct defect repair technique. This invention enables the fabrication of defect-free (since repaired) X-ray Mo--Si multilayer mirrors. Repairing Mo--Si multilayer-film defects on mask blanks is a key for the commercial success of EUVL. It is known that particles are added to the Mo--Si multilayer film during the fabrication process. There is a large effort to reduce this contamination, but results are not sufficient, and defects continue to be a major mask yield limiter. All suggested repair strategies need to know the out-of-plane position of the defects in the multilayer.

  15. Anatomical masking of pressure footprints based on the Oxford Foot Model: validation and clinical relevance.

    PubMed

    Giacomozzi, Claudia; Stebbins, Julie A

    2017-03-01

    Plantar pressure analysis is widely used in the assessment of foot function. In order to assess regional loading, a mask is applied to the footprint to sub-divide it into regions of interest (ROIs). The most common masking method is based on geometric features of the footprint (GM). Footprint masking based on anatomical landmarks of the foot has been implemented more recently, and involves the integration of a 3D motion capture system, plantar pressure measurement device, and a multi-segment foot model. However, thorough validation of anatomical masking (AM) using pathological footprints has not yet been presented. In the present study, an AM method based on the Oxford Foot Model (OFM) was compared to an equivalent GM. Pressure footprints from 20 young healthy subjects (HG) and 20 patients with clubfoot (CF) were anatomically divided into 5 ROIs using a subset of the OFM markers. The same foot regions were also identified by using a standard GM method. Comparisons of intra-subject coefficient of variation (CV) showed that the OFM-based AM was at least as reliable as the GM for all investigated pressure parameters in all foot regions. Clinical relevance of AM was investigated by comparing footprints from HG and CF groups. Contact time, maximum force, force-time integral and contact area proved to be sensitive parameters that were able to distinguish HG and CF groups, using both AM and GM methods However, the AM method revealed statistically significant differences between groups in 75% of measured variables, compared to 62% using a standard GM method, indicating that the AM method is more sensitive for revealing differences between groups. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Recent advances in SEMATECH's mask blank development program, the remaining technical challenges, and future outlook

    NASA Astrophysics Data System (ADS)

    Goodwin, Frank; Kearney, Patrick; Kadaksham, Arun J.; Wurm, Stefan

    2013-10-01

    The ability of optical lithography to steadily produce images at increasingly smaller dimension while maintaining pattern fidelity of devices with greater complexity has enabled the success of Moore's Law. Although 193 nm immersion and double patterning techniques have proven successful in extending optical lithography, the strategies proposed for further extension are too costly to support device manufacturing. As a result, greater focus has been shifted to resolving the challenges hindering extreme ultraviolet lithography (EUVL) adoption as the mainstream lithography solution. While similar to conventional optical lithography, there are unique challenges to EUVL, one of which is the change from transmission masks to the reflective masks required for EUVL. The use of reflective reticles greatly increases complexity of EUV reticle structure when compared to the binary masks used with optical lithography. Maximizing the reflectance an EUV mask requires the use of a multilayer Bragg reflector deposited on a finely polished substrate with a thin absorber film on top used to define the device pattern. Although similar in form to the substrates used in optical lithography, the tolerances on figure, surface finish, and defects are significantly more stringent for EUV substrates. Control of aberrations and maintaining pattern fidelity places tight constraints on the flatness and roughness of the EUV substrate; imperfections and particles can result in printable defects. The Bragg reflector of the EUV mask consists of 40 to 50 Si/Mo bi-layers deposited using an ion beam deposition tool. This film stack must be deposited to meet the reflectivity and uniformity requirements of the exposure tool and must be completely free of defects. The absorber film is typically a tantalum-based nitride layer selected for its ability to absorb EUV radiation and maintain thermal stability. The thickness and morphology of this film must be tightly controlled to enable use as the patterning

  17. Actinic review of EUV masks: status and recent results of the AIMSTM EUV system

    NASA Astrophysics Data System (ADS)

    Perlitz, Sascha; Peters, Jan Hendrik; Weiss, Markus; Hellweg, Dirk; Capelli, Renzo; Magnusson, Krister; Malloy, Matt; Wurm, Stefan

    2015-10-01

    Key enabler of the successful introduction of EUV lithography into volume production is the EUV mask infrastructure. For the production of defect free masks, actinic review of potential defect sites to decide on the need for repair or compensation is required. Also, the repair or compensation with the ZEISS MERiT electron beam repair tool needs actinic verification in a closed loop mask repair solution. For the realization of actinic mask review, ZEISS and the SEMATECH EUVL Mask Infrastructure consortium started a development program for an EUV aerial image metrology system, the AIMSTM EUV, with realization of a prototype tool. The development and prototype realization of the AIMSTM EUV has entered the tool calibration and qualification phase utilizing the achieved capabilities of EUV aerial image acquisition and EUV mask handling. In this paper, we discuss the current status of the prototype qualification and show recent measurement results.

  18. Modeling of charging effect and its correction by EB mask writer EBM-6000

    NASA Astrophysics Data System (ADS)

    Nakayamada, Noriaki; Wake, Seiji; Kamikubo, Takashi; Sunaoshi, Hitoshi; Tamamushi, Shuichi

    2008-05-01

    The impending need of double patterning/double exposure techniques is accelerating the demand for higher pattern placement accuracy to be achieved in the upcoming lithography generations. One of the biggest error sources of pattern placement accuracy on an EB mask writer is the resist charging effect. In this paper, we provide a model to describe the resist charging behavior on a photomask written on our EBM-6000 system. We found this model was very effective in correcting and reducing the beam position error induced by the charging effect.

  19. Electron beam inspection of 16nm HP node EUV masks

    NASA Astrophysics Data System (ADS)

    Shimomura, Takeya; Narukawa, Shogo; Abe, Tsukasa; Takikawa, Tadahiko; Hayashi, Naoya; Wang, Fei; Ma, Long; Lin, Chia-Wen; Zhao, Yan; Kuan, Chiyan; Jau, Jack

    2012-11-01

    EUV lithography (EUVL) is the most promising solution for 16nm HP node semiconductor device manufacturing and beyond. The fabrication of defect free EUV mask is one of the most challenging roadblocks to insert EUVL into high volume manufacturing (HVM). To fabricate and assure the defect free EUV masks, electron beam inspection (EBI) tool will be likely the necessary tool since optical mask inspection systems using 193nm and 199nm light are reaching a practical resolution limit around 16nm HP node EUV mask. For production use of EBI, several challenges and potential issues are expected. Firstly, required defect detection sensitivity is quite high. According to ITRS roadmap updated in 2011, the smallest defect size needed to detect is about 18nm for 15nm NAND Flash HP node EUV mask. Secondly, small pixel size is likely required to obtain the high sensitivity. Thus, it might damage Ru capped Mo/Si multilayer due to accumulated high density electron beam bombardments. It also has potential of elevation of nuisance defects and reduction of throughput. These challenges must be solved before inserting EBI system into EUV mask HVM line. In this paper, we share our initial inspection results for 16nm HP node EUV mask (64nm HP absorber pattern on the EUV mask) using an EBI system eXplore® 5400 developed by Hermes Microvision, Inc. (HMI). In particularly, defect detection sensitivity, inspectability and damage to EUV mask were assessed. As conclusions, we found that the EBI system has capability to capture 16nm defects on 64nm absorber pattern EUV mask, satisfying the sensitivity requirement of 15nm NAND Flash HP node EUV mask. Furthermore, we confirmed there is no significant damage to susceptible Ru capped Mo/Si multilayer. We also identified that low throughput and high nuisance defect rate are critical challenges needed to address for the 16nm HP node EUV mask inspection. The high nuisance defect rate could be generated by poor LWR and stitching errors during EB writing

  20. EUV mask reflectivity measurements with micro-scale spatial resolution

    SciTech Connect

    Goldberg, Kenneth A.; Rekawa, Senajith B.; Kemp, Charles D.; Barty, Anton; Anderson, Erik; Kearney, Patrick; Han, Hakseung

    2008-02-01

    The effort to produce defect-free mask blanks for EUV lithography relies on increasing the detection sensitivity of advanced mask inspection tools, operating at several wavelengths. They describe the unique measurement capabilities of a prototype actinic (EUV) wavelength microscope that is capable of detecting small defects and reflectivity changes that occur on the scale of microns to nanometers. The defects present in EUV masks can appear in many well-known forms: as particles that cause amplitude or phase variations in the reflected field; as surface contamination that reduces reflectivity and contrast; and as damage from inspection and use that reduces the reflectivity of the multilayer coating. This paper presents an overview of several topics where scanning actinic inspection makes a unique contribution to EUVL research. They describe the role of actinic scanning inspection in defect repair studies, observations of laser damage, actinic inspection following scanning electron microscopy, and the detection of both native and programmed defects.

  1. Formal specification and verification of a fault-masking and transient-recovery model for digital flight-control systems

    NASA Technical Reports Server (NTRS)

    Rushby, John

    1991-01-01

    The formal specification and mechanically checked verification for a model of fault-masking and transient-recovery among the replicated computers of digital flight-control systems are presented. The verification establishes, subject to certain carefully stated assumptions, that faults among the component computers are masked so that commands sent to the actuators are the same as those that would be sent by a single computer that suffers no failures.

  2. Attenuated phase-shift mask for mitigation of photon shot noise effect in contact hole pattern for extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Kim, Jung Sik; Hong, Seongchul; Lee, Jae Uk; Lee, Seung Min; Ahn, Jinho

    2014-09-01

    In extreme ultraviolet lithography (EUVL), insufficient light source power is the biggest concern for high-volume manufacturing. Additionally, the photon shot noise (PSN) effect is believed to be the main source of degradation in various aspects of imaging performance. In this study, we propose an attenuated phase-shift mask (PSM) as a solution to both of these issues, yielding improved mask performance for the printing of small contact hole (C/H) patterns. Our PSM shows superior imaging performance over that of a binary intensity mask. We speculate that the stochastic imaging characteristics are improved by the enhanced diffraction efficiency of the PSM.

  3. Retention of pediatric bag-mask ventilation efficacy skill by inexperienced medical student resuscitators using standard bag-mask ventilation masks, pocket masks, and blob masks.

    PubMed

    Kitagawa, Kory H; Nakamura, Nina M; Yamamoto, Loren

    2006-03-01

    To measure the ventilation efficacy with three single-sized mask types on infant and child manikin models. Medical students were recruited as study subjects inasmuch as they are inexperienced resuscitators. They were taught proper bag-mask ventilation (BMV) according to the American Heart Association guidelines on an infant and a child manikin. Subjects completed a BMV attempt successfully using the adult standard mask (to simulate the uncertainty of mask selection), pocket mask, and blob mask. Each attempt consisted of 5 ventilations assessed by chest rise of the manikin. Study subjects were asked which mask was easiest to use. Four to six weeks later, subjects repeated the procedure with no instructions (to simulate an emergency BMV encounter without immediate pre-encounter teaching). Forty-six volunteer subjects were studied. During the first attempt, subjects preferred the standard and blob masks over the pocket mask. For the second attempt, the blob mask was preferred over the standard mask, and few liked the pocket mask. Using the standard, blob, and pocket masks on the child manikin, 39, 42, and 20 subjects, respectively, were able to achieve adequate ventilation. Using the standard, blob, and pocket masks on the infant manikin, 45, 45, and 11 subjects, respectively, were able to achieve adequate ventilation. Both the standard and blob masks are more effective than the pocket mask at achieving adequate ventilation on infant and child manikins in this group of inexperienced medical student resuscitators, who most often preferred the blob mask.

  4. A pattern- and optics-independent compact model of Mask3D under off-axis illumination with significant efficiency and accuracy improvements

    NASA Astrophysics Data System (ADS)

    Zhang, Hongbo; Yan, Qiliang; Wei, David; Croffie, Ebo

    2015-03-01

    As the critical dimension keeps shrinking, mask topography effect (Mask3D) becomes considerable to impact the lithography modeling accuracy and the quality of full-chip OPC. Among many challenges in Mask3D modeling, it is critical and particularly demanding to treat off-axis illumination (OAI) properly. In this paper, we present a novel Mask3D model that is completely test pattern- and optics- independent. Such model property enables greatly improved performance in terms of accuracy and consistency on various pattern types (1D/2D) and through a wide range of focus conditions, while no runtime overhead is incurred. The novel model and formulation will be able to save significant modeling time and greatly improve the model reliability, predictability and ease of use. Experimental results validate the claims and demonstrate the superiority to the current state-of-the-art Mask3D modeling method. This is a new generation Mask3D modeling process.

  5. Prediction of Masked Chafer, Cyclocephala pasadenae, Capture in Light Traps Using a Degree-Day Model

    PubMed Central

    Blanco, Carlos A.; Hernández, Gerardo

    2006-01-01

    In order to obtain information on the biology of the masked chafer Cyclocephala pasadenae (Coleoptera: Scarabaeidae), and to determine the date when 50% of the population is captured in light traps, field data were obtained during 4 years in Albuquerque, New Mexico. Capture of the 50% of the masked chafer population occurred approximately during the third week of July, of this one-generation per year insect. To reduce the need for intensive sampling and to obtain a predictable model for the capture of this pest, data were analyzed using trapezoidal numerical integration to estimate both a lower threshold and degree-days to predict the 50% capture date. A mathematical model based on field data accounted for the influence of natural environmental conditions on development, and predicted 50% capture dates within 1–4 days of what was actually observed from the field. The difference between predictions from field data is smaller than using estimates from laboratory-controlled experiments. The model presented here could serve as an accurate estimator of the appropriate timing to implement control measures of this important turfgrass pest.

  6. AutoMOPS- B2B and B2C in mask making: Mask manufacturing performance and customer satisfaction improvement through better information flow management using generic models and standardized languages

    NASA Astrophysics Data System (ADS)

    Filies, Olaf; de Ridder, Luc; Rodriguez, Ben; Kujiken, Aart

    2002-03-01

    Semiconductor manufacturing has become a global business, in which companies of different size unite in virtual enterprises to meet new opportunities. Therefore Mask manufacturing is a key business, but mask ordering is a complex process and is always critical regarding design to market time, even though mask complexity and customer base are increasing using a wide variety of different mask order forms which are frequently faulty and very seldom complete. This is effectively blocking agile manufacturing and can tie wafer fabs to a single mask The goal of the project is elimination of the order verification through paperless, electronically linked information sharing/exchange between chip design, mask production and production stages, which will allow automation of the mask preparation. To cover these new techniques and their specifications as well as the common ones with automated tools a special generic Meta-model will be generated, based on the current standards for mask specifications, including the requirements from the involved partners (Alcatel Microelectronics, Altis, Compugraphics, Infineon, Nimble, Sigma-C), the project works out a pre-normative standard. The paper presents the current status of work. This work is partly funded by the Commission of the European Union under the Fifth Framework project IST-1999-10332 AutoMOPS.

  7. 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.

  8. Highly selective etching of SnO2 absorber in binary mask structure for extreme ultra-violet lithography.

    PubMed

    Lee, Soo Jin; Jung, Chang Yong; Park, Sung Jin; Hwangbo, Chang Kweun; Seo, Hwan Seok; Kim, Sung Soo; Lee, Nae-Eung

    2012-04-01

    Among the core EUVL (extreme ultra-violet lithography) technologies for nanoscale patterning below the 30 nm node for Si chip manufacturing, new materials and fabrication processes for high-performance EUVL masks are of considerable importance due to the use of new reflective optics. In this work, the selective etching of SnO2 (tin oxide) as a new absorber material, with high EUV absorbance due to its large extinction coefficient, for the binary mask structure of SnO2 (absorber layer)/Ru (capping/etch stop layer)/Mo-Si multilayer (reflective layer)/Si (substrate), was investigated. Because infinitely high selectivity of the SnO2 layer to the Ru ESL is required due to the ultrathin nature of the Ru layer, various etch parameters were assessed in the inductively coupled Cl2/Ar plasmas in order to find the process window required for infinitely high etch selectivity of the SnO2 layer. The results showed that the gas flow ratio and V(dc) value play an important role in determining the process window for the infinitely high etch selectivity of SnO2 to Ru ESL. The high EUV-absorbance SnO2 layer, patternable by a dry process, allows a smaller absorber thickness, which can mitigate the geometric shadowing effects observed for high-performance binary EUVL masks.

  9. Experimental study of particle-free mask handling

    NASA Astrophysics Data System (ADS)

    Amemiya, Mitsuaki; Ota, Kazuya; Taguchi, Takao; Suga, Osamu

    2009-03-01

    One of the critical issues for EUVL masks is clean and particle-free mask handling. We reported that the number of particle adders on the front side of a mask in the dual pod during the process from the load port to putting on the Electrostatic chuck (ESC) in vacuum could be reduce to less than 0.01 particle/cycle (>=46 nm). In addition, we found that chucking the mask on the ESC caused two serious issues. The first is that many particles stick to on the backside of the mask after chucking on the ESC, raising the question of whether the particle adders on the backside will travel to the front side. We examined the travel of these particles using the substrates after chucking and polystyrene latex (PSL) substrates that were dispersed on the backside. These experiments show that there is very little probability that particles on the backside will travel to the front side. The second issue is whether the mask blanks will charge up by chucking on the ESC and some particles will add on the front side. We measured the electric potential of the back and front sides of the mask and examined the particle adders. Our experiments revealed that to protect the mask from the particles, the mask must be grounded from the beginning to the end. For these two issues, we confirmed that a dual pod system works effectively to protect the mask from particles. This work is supported by NEDO as a part of the EUV mask program.

  10. Computer models for masked hearing experiments with beluga whales (Delphinapterus leucas).

    PubMed

    Erbe, C; King, A R; Yedlin, M; Farmer, D M

    1999-05-01

    Environmental assessments of manmade noise and its effects on marine mammals need to address the question of how noise interferes with animal vocalizations. Seeking the answer with animal experiments is very time consuming, costly, and often infeasible. This article examines the possibility of estimating results with software models. A matched filter, spectrogram cross-correlation, critical band cross-correlation, and a back-propagation neural network detected a beluga vocalization in three types of ocean noise. Performance was compared to masked hearing experiments with a beluga whale [C. Erbe and D. M. Farmer, Deep-Sea Res. II 45, 1373-1388 (1998)]. The artificial neural network simulated the animal data most closely and raised confidence in its ability to predict the interference of a variety of noise source with a variety of vocalizations.

  11. Efficient modeling of immersion lithography in an aggressive RET mask synthesis flow

    NASA Astrophysics Data System (ADS)

    Bai, Min; Lei, Junjiang; Zhang, Lin; Shiely, James P.

    2005-06-01

    Immersion lithography has been accepted as the major breakthrough for enabling next generation deep subwavelength chip production. As it extends the resolution capability of optical lithography to the next technology node, it brings fresh challenges to resolution enhancement techniques (RET). Accurate lithography modeling becomes even more critical for RET at the sub-65nm nodes. On the other hand, immersion models need to be fully compatible within the context of existing optical proximity correction (OPC) flow. With the hyper NA approach, modeling of immersion lithography requires full vector treatment of the electric fields in the propagating light wave. We developed a comprehensive vector model that considers not only the plane wave decomposition from the mask to the wafer plane, but also the light propagation through a thin film stack on the wafer. With the integration of this model into Synopsys OPC modeling tool ProGen, we have simulated and demonstrated several important enhancements introduced by immersion. In the mean time, the modeling and correction flow for immersion is completely compatible with the current OPC infrastructure.

  12. EUV mask reflectivity measurements with micron-scale spatial resolution

    SciTech Connect

    Goldberg, Kenneth A.; Rekawa, S.B.; Kemp, C.D.; Barty, A.; Anderson, E.H.; Kearney, Patrick; Han, Hakseung

    2008-05-26

    The effort to produce defect-free mask blanks for EUV lithography relies on increasing the detection sensitivity of advanced mask inspection tools, operating at several wavelengths. We describe the unique measurement capabilities of a prototype actinic (EUV wavelength) microscope that is capable of detecting small defects and reflectivity changes that occur on the scale of microns to nanometers. Types of defects: (a) Buried Substrate Defects: particles & pits (causes amplitude and/or phase variations); (b) Surface Contamination (reduces reflectivity and (possibly) contrast); (c) Damage from Inspection and Use (reduces the reflectivity of the multilayer coating). This paper presents an overview of several topics where scanning actinic inspection makes a unique contribution to EUVL research. We describe the role of actinic scanning inspection in four cases: defect repair studies; observations of laser damage; after scanning electron microscopy; and native and programmed defects.

  13. A cocktail party model of spatial release from masking by both noise and speech interferers.

    PubMed

    Jones, Gary L; Litovsky, Ruth Y

    2011-09-01

    A mathematical formula for estimating spatial release from masking (SRM) in a cocktail party environment would be useful as a simpler alternative to computationally intensive algorithms and may enhance understanding of underlying mechanisms. The experiment presented herein was designed to provide a strong test of a model that divides SRM into contributions of asymmetry and angular separation [Bronkhorst (2000). Acustica 86, 117-128] and to examine whether that model can be extended to include speech maskers. Across masker types the contribution to SRM of angular separation of maskers from the target was found to grow at a diminishing rate as angular separation increased within the frontal hemifield, contrary to predictions of the model. Speech maskers differed from noise maskers in the overall magnitude of SRM and in the contribution of angular separation (both greater for speech). These results were used to develop a modified model that achieved good fits to data for noise maskers (ρ=0.93) and for speech maskers (ρ=0.94) while using the same functions to describe separation and asymmetry components of SRM for both masker types. These findings suggest that this approach can be used to accurately model SRM for speech maskers in addition to primarily "energetic" noise maskers.

  14. A cocktail party model of spatial release from masking by both noise and speech interferers a)

    PubMed Central

    Jones, Gary L.; Litovsky, Ruth Y.

    2011-01-01

    A mathematical formula for estimating spatial release from masking (SRM) in a cocktail party environment would be useful as a simpler alternative to computationally intensive algorithms and may enhance understanding of underlying mechanisms. The experiment presented herein was designed to provide a strong test of a model that divides SRM into contributions of asymmetry and angular separation [Bronkhorst (2000). Acustica 86, 117–128] and to examine whether that model can be extended to include speech maskers. Across masker types the contribution to SRM of angular separation of maskers from the target was found to grow at a diminishing rate as angular separation increased within the frontal hemifield, contrary to predictions of the model. Speech maskers differed from noise maskers in the overall magnitude of SRM and in the contribution of angular separation (both greater for speech). These results were used to develop a modified model that achieved good fits to data for noise maskers (ρ = 0.93) and for speech maskers (ρ = 0.94) while using the same functions to describe separation and asymmetry components of SRM for both masker types. These findings suggest that this approach can be used to accurately model SRM for speech maskers in addition to primarily “energetic” noise maskers. PMID:21895087

  15. Mask defect verification using actinic inspection and defect mitigation technology

    SciTech Connect

    Huh, Sungmin; Kearney, Patrick; Wurm, Stefan; Goodwin, Frank; Goldberg, Kenneth; Mochi, Iacopo; Gullikson, Eric

    2009-04-14

    The availability of defect-free masks remains one of the key challenges for inserting extreme ultraviolet lithography (EUVL) into high volume manufacturing. The successful production of defect-free masks will depend on the timely development of defect inspection tools, including both mask blank inspection tools and absorber pattern inspection tools to meet the 22 nm half-pitch node. EUV mask blanks with embedded phase defects were inspected with a reticle actinic inspection tool (AIT) and the Lasertec M7360. The Lasertec M7360 is operated at SEMA TECH's Mask blank Development Center (MBDC) in Albany, with sensitivity to multilayer defects down to 40-45 nm, which is not likely sufficient for mask blank development below the 32 nm half-pitch node. Phase defect printability was simulated to calculate the required defect sensitivity for the next generation blank inspection tool to support reticle development for the sub-32 nm half-pitch technology node. This paper will also discuss the kind of infrastructure that will be required in the development and mass production stages.

  16. A method for repairing amplitude defects in multilayer-coated EUV mask blanks

    SciTech Connect

    Barty, A; Hau-Riege, S; Stearns, D; Clift, M; Mirkarimi, P; Gullikson, E; Chapman, H; Sweeney, D

    2003-10-20

    EUV mask blanks are fabricated by depositing a reflective Mo/Si multilayer film onto super-polished substrates. Localized defects in this thin film coating can significantly perturb the reflected field and produce errors in the printed image. Ideally one would want to manufacture 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 be able to repair a significant number of the defects in the multilayer coating. In this paper we present a method for repairing defects that are near the top surface of the coating; we call these amplitude defects because they predominantly attenuate the amplitude of the reflected field. Although the discussion is targeted to the application of manufacturing masks for EUV lithography, the conclusions and results are also applicable to understanding the optical effects of multilayer erosion, including ion-induced multilayer erosion and condenser erosion in EUVL steppers.

  17. Masked translation priming asymmetry in Chinese-English bilinguals: making sense of the Sense Model.

    PubMed

    Xia, Violet; Andrews, Sally

    2015-01-01

    Masked translation priming asymmetry is the robust finding that priming from a bilingual's first language (L1) to their second language (L2) is stronger than priming from L2 to L1. This asymmetry has been claimed to be task dependent. The Sense Model proposed by Finkbeiner, Forster, Nicol, and Nakamura (2004) claims that the asymmetry is reduced in semantic categorization relative to lexical decision due to a category filtering mechanism that limits the features considered in categorization decisions to dominant, category-relevant features. This paper reports two pairs of semantic categorization and lexical decision tasks designed to test the Sense Model's predictions. The experiments replicated the finding of Finkbeiner et al. that L2-L1 priming is somewhat stronger in semantic categorization than lexical decision, selectively for exemplars of the category. However, the direct comparison of L2-L1 and L1-L2 translation priming across tasks failed to confirm the Sense Model's central prediction that translation priming asymmetry is significantly reduced in semantic categorization. The data therefore fail to support the category filtering account of translation priming asymmetry. Rather, they suggest that pre-activation of conceptual features of the target category provides feedback to lexical forms that compensates for the weak connections between the lexical and conceptual representations of L2 words.

  18. Compensation methods using a new model for buried defects in extreme ultraviolet lithography masks

    NASA Astrophysics Data System (ADS)

    Clifford, Chris H.; Chan, Tina T.; Neureuther, Andrew R.; Li, Ying; Peng, Danping; Pang, Linyong

    2010-09-01

    A new method for predicting the reflection from an extreme ultraviolet (EUV) multilayer is described which when implemented into the new Defect Printability Simulator (DPS) can calculate the image produced by an EUV mask with a buried defect several orders of magnitude faster than the finite difference time domain (FDTD). A new buried defect compensation method is also demonstrated to correct the in focus image of a line space pattern containing a buried defect. The new multilayer model accounts for the disruption of the magnitude and phase of the reflected field from an EUV multilayer defect. It does this by sampling the multilayer on a non-uniform grid and calculating the analytic complex local reflection coefficient at each point. After this step, the effect of the optical path difference due to the surface defect profile is added to the total reflected field to accurately predict the reflected magnitude and phase at all points on the multilayer surface. The accuracy of the new multilayer model and the full DPS simulator is verified by comparisons to FDTD simulations. The largest difference between the two methods was 0.8nm for predicting the CD change due to a buried defect through focus. This small difference is within the margin of error for FDTD simulations of EUV multilayers. The runtime of DPS is compared to extrapolated FDTD runtimes for many simulation domain sizes and DPS is 4-5 orders of magnitude faster for all cases. For example, DPS can calculate the reflected image from a 1μm x 1μm mask area in less than 30 seconds on a single processor. FDTD would take a month on four processors. The new compensation strategy demonstrated in this work is able to remove all CD error in the simulated image due to a buried defect in a 22nm dense line space pattern. The method is iterative and a full DPS simulation is run for every iteration. After each simulation, the absorber pattern is adjusted based on the difference of the thresholded target image and

  19. Printability and inspectability of Defects on the EUV Mask for sub32nm Half Pitch HVM Application

    SciTech Connect

    Huh, S.; Kang, I.-Y.; Kim, S.-H.; Seo, H.-S.; Kim, D.; Park, J.; Kim, S.-S.; Cho, H.-K.; Goldberg, K.; Mochi, I.; Shoki, T.; Indeerhees, G.

    2011-01-10

    The availability of defect-free masks remains one of the key challenges for inserting extreme ultraviolet lithography (EUVL) into high volume manufacturing, yet little data is available for understanding native defects on real masks. In this paper, a full field EUV mask is fabricated to see the printability of various defects on the mask. Programmed pit defect shows that minimum printable size of pits could be 17 nm of SEVD from the AIT. However 23.1nm in SEVD is printable from the EUV ADT. Defect printability and identification of its source along from blank fabrication to mask fabrication were studied using various inspection tools. Capture ratio of smallest printable defects was improved to 80% using optimized stack of metrical on wafer and state-of-art wafer inspection tool. Requirement of defect mitigation technology using fiducial mark are defined.

  20. Mask requirements for advanced lithography

    NASA Astrophysics Data System (ADS)

    Trybula, Walter J.; Engelstad, Roxann L.

    1998-06-01

    Within the n ext 10 years, sub-100 nm features will be required for state-of-the-industry devices. The tolerances for errors at 100 nm or less are substantially smaller than can be achieved today. A critical element of the error budget is the mask. For the 100 nm generation, the 4x mask image placement requirement is 20 nm with CD requirements as low as 9 nm. The challenge would be significant if the only improvement were to develop superior optical masks. There are multiple advanced technologies that are vying to be the successor to optical lithography. Each of these has a unique mask requirement. The leading contenders for the next generation are 1x x-ray, projection e-beam, ion beam, EUV and cell projection e-beam. The x-ray design is a proximity system that employs a 1x membrane mask. Projection e-beam uses a membrane mask with stabilizing struts. Ion beam lithography employs a stencil membrane mask with a carbon coating. EUV employs a 13 nm radiation source that requires a reflective mask. Cell projection e-beam has 25x or greater image masks that are stitched on the wafer. All the technologies indicated above. Once a total error budget for the mask is known, it is necessary to divide the total into the constituent parts. The major sources of distortion can be categorized into eight areas: mask blank processing, e- beam writing, pattern transfer, pellicle effects, mounting, thermal loadings, dynamic effects during exposure and radiation damage. The distortions introduced by each of these depend upon the type of mask; so, individual mask calculations must be made. The purpose of this paper is to review the modeling requirements of each of the categories and to highlight some results from each of the mask configurations.

  1. Model-based edge detector for spectral imagery using sparse spatiospectral masks.

    PubMed

    Paskaleva, Biliana S; Godoy, Sebastián E; Jang, Woo-Yong; Bender, Steven C; Krishna, Sanjay; Hayat, Majeed M

    2014-05-01

    Two model-based algorithms for edge detection in spectral imagery are developed that specifically target capturing intrinsic features such as isoluminant edges that are characterized by a jump in color but not in intensity. Given prior knowledge of the classes of reflectance or emittance spectra associated with candidate objects in a scene, a small set of spectral-band ratios, which most profoundly identify the edge between each pair of materials, are selected to define a edge signature. The bands that form the edge signature are fed into a spatial mask, producing a sparse joint spatiospectral nonlinear operator. The first algorithm achieves edge detection for every material pair by matching the response of the operator at every pixel with the edge signature for the pair of materials. The second algorithm is a classifier-enhanced extension of the first algorithm that adaptively accentuates distinctive features before applying the spatiospectral operator. Both algorithms are extensively verified using spectral imagery from the airborne hyperspectral imager and from a dots-in-a-well midinfrared imager. In both cases, the multicolor gradient (MCG) and the hyperspectral/spatial detection of edges (HySPADE) edge detectors are used as a benchmark for comparison. The results demonstrate that the proposed algorithms outperform the MCG and HySPADE edge detectors in accuracy, especially when isoluminant edges are present. By requiring only a few bands as input to the spatiospectral operator, the algorithms enable significant levels of data compression in band selection. In the presented examples, the required operations per pixel are reduced by a factor of 71 with respect to those required by the MCG edge detector.

  2. TinyTim modeling of NICMOS PSF subtraction: effects of focus breathing, cold mask wiggling, and color variations

    NASA Astrophysics Data System (ADS)

    Suchkov, A.; Krist, J.

    1998-11-01

    We conduct TinyTim modeling of NICMOS camera 2 PSFs to assess limits to the accuracy of PSF subtraction imposed by color dependence, OTA focus breathing, and cold mask wiggling. The results suggest that effects of both cold mask wiggling and focus breathing can be described as a noise in a PSF-subtracted image, well above 20% of the PSF signal in narrow band filters, with a spatial scale of a few pixels. The main effect of the PSF color dependence is adding a systemic component to the PSF subtracted image. The effect is quite large if the color of the PSF used for subtraction is very different from the image PSF color. It is pronounced in blue, wide filters, like F110W, while in filters like F187W or redder/ narrower it is essentially negligible.

  3. Image-based pupil plane characterization via principal component analysis for EUVL tools

    NASA Astrophysics Data System (ADS)

    Levinson, Zac; Burbine, Andrew; Verduijn, Erik; Wood, Obert; Mangat, Pawitter; Goldberg, Kenneth A.; Benk, Markus P.; Wojdyla, Antoine; Smith, Bruce W.

    2016-03-01

    We present an approach to image-based pupil plane amplitude and phase characterization using models built with principal component analysis (PCA). PCA is a statistical technique to identify the directions of highest variation (principal components) in a high-dimensional dataset. A polynomial model is constructed between the principal components of through-focus intensity for the chosen binary mask targets and pupil amplitude or phase variation. This method separates model building and pupil characterization into two distinct steps, thus enabling rapid pupil characterization following data collection. The pupil plane variation of a zone-plate lens from the Semiconductor High-NA Actinic Reticle Review Project (SHARP) at Lawrence Berkeley National Laboratory will be examined using this method. Results will be compared to pupil plane characterization using a previously proposed methodology where inverse solutions are obtained through an iterative process involving least-squares regression.

  4. Modeling and Simulating Multiple Failure Masking enabled by Local Recovery for Stencil-based Applications at Extreme Scales

    DOE PAGES

    Gamell, Marc; Teranishi, Keita; Mayo, Jackson; ...

    2017-04-24

    By obtaining multi-process hard failure resilience at the application level is a key challenge that must be overcome before the promise of exascale can be fully realized. Some previous work has shown that online global recovery can dramatically reduce the overhead of failures when compared to the more traditional approach of terminating the job and restarting it from the last stored checkpoint. If online recovery is performed in a local manner further scalability is enabled, not only due to the intrinsic lower costs of recovering locally, but also due to derived effects when using some application types. In this papermore » we model one such effect, namely multiple failure masking, that manifests when running Stencil parallel computations on an environment when failures are recovered locally. First, the delay propagation shape of one or multiple failures recovered locally is modeled to enable several analyses of the probability of different levels of failure masking under certain Stencil application behaviors. These results indicate that failure masking is an extremely desirable effect at scale which manifestation is more evident and beneficial as the machine size or the failure rate increase.« less

  5. Neural mechanisms of rhythmic masking release in monkey primary auditory cortex: implications for models of auditory scene analysis.

    PubMed

    Fishman, Yonatan I; Micheyl, Christophe; Steinschneider, Mitchell

    2012-05-01

    The ability to detect and track relevant acoustic signals embedded in a background of other sounds is crucial for hearing in complex acoustic environments. This ability is exemplified by a perceptual phenomenon known as "rhythmic masking release" (RMR). To demonstrate RMR, a sequence of tones forming a target rhythm is intermingled with physically identical "Distracter" sounds that perceptually mask the rhythm. The rhythm can be "released from masking" by adding "Flanker" tones in adjacent frequency channels that are synchronous with the Distracters. RMR represents a special case of auditory stream segregation, whereby the target rhythm is perceptually segregated from the background of Distracters when they are accompanied by the synchronous Flankers. The neural basis of RMR is unknown. Previous studies suggest the involvement of primary auditory cortex (A1) in the perceptual organization of sound patterns. Here, we recorded neural responses to RMR sequences in A1 of awake monkeys in order to identify neural correlates and potential mechanisms of RMR. We also tested whether two current models of stream segregation, when applied to these responses, could account for the perceptual organization of RMR sequences. Results suggest a key role for suppression of Distracter-evoked responses by the simultaneous Flankers in the perceptual restoration of the target rhythm in RMR. Furthermore, predictions of stream segregation models paralleled the psychoacoustics of RMR in humans. These findings reinforce the view that preattentive or "primitive" aspects of auditory scene analysis may be explained by relatively basic neural mechanisms at the cortical level.

  6. The energetics of mask wear.

    PubMed

    Johnson, A T

    1976-08-01

    Experimental data further defining the region of predominant respiratory stress is presented. Within this region, energy requirements of respiration increase disproportionately to the overall energy expenditure of the body as excercise intensity increases. Addition of a mask accentuates this tendency, especially since no physiological compensation is possible in mask parameters. Mask technology has improved masks to the point where they no longer dominate the man-mask system, but instead contribute resistances and dead volumes approximately equal to those naturally occurring in man. Modeling base on minimization of respiratory energy rate of expenditure in the human is applied to this man-mask system and predictions are made which to this point have been nearly impossible to obtain from experimental data.

  7. Mask cost and specification

    NASA Astrophysics Data System (ADS)

    Watanabe, Hisashi; Higashikawa, Iwao

    2003-12-01

    At the panel discussion of Photomask Japan 2003, we discussed about Mask cost and specification. The topics are (1) Mask price trend and its impact, (2) How to reduce the mask costs; solutions from a mask shop, mask writing tool and mask inspection tool 3) Partnering mask suppliers with mask users; reasonable mask specification and OPC strategies. The choice of DUV laser writer instead of e-beam writer is one solution for reduction of mask cost. The continuous improvement of e-beam writer and resist sensitivity for high throughput is another solution. The partnership between designer, EDA vender, mask maker and wafer lithographer becomes more important.

  8. Clay Mask Workshop

    ERIC Educational Resources Information Center

    Gamble, David L.

    2012-01-01

    Masks can represent so many things, such as emotions (happy, sad, fearful) and power. The familiar "comedy and tragedy" masks, derived from ancient Greek theater, are just one example from mask history. Death masks from the ancient Egyptians influenced the ancient Romans into creating similar masks for their departed. Masks can represent many…

  9. Clay Mask Workshop

    ERIC Educational Resources Information Center

    Gamble, David L.

    2012-01-01

    Masks can represent so many things, such as emotions (happy, sad, fearful) and power. The familiar "comedy and tragedy" masks, derived from ancient Greek theater, are just one example from mask history. Death masks from the ancient Egyptians influenced the ancient Romans into creating similar masks for their departed. Masks can represent many…

  10. Scanning coherent scattering methods for actinic EUV mask inspection

    NASA Astrophysics Data System (ADS)

    Ekinci, Y.; Helfenstein, P.; Rajeev, R.; Mochi, I.; Mohacsi, I.; Gobrecht, J.; Yoshitake, S.

    2016-10-01

    Actinic mask inspection for EUV lithography with targeted specifications of resolution, sensitivity, and throughput remains a big hurdle for the successful insertion of EUVL into high volume manufacturing and effective solutions are needed to address this. We present a method for actinic mask inspection based on scanning coherent scattering microscopy. In this method, the mask is scanned with an EUV beam of relatively small spot size and the scattered light is recorded with a pixel detector. Customized algorithms reconstruct the aerial image by iteratively solving the phaseproblem using over-determined diffraction data gathered by scanning across the specimen with a finite illumination. This approach provides both phase and amplitude of actinic aerial images of the mask with high resolution without the need to use high NA (numerical aperture) lenses. Futher, we describe a reflective mode EUV mask scanning lensless imaging tool (RESCAN), which was installed at the XIL-II beamline and later at the SIM beamline of the Swiss Light Source and show reconstructed aerial images down to 10 nm (on-wafer) resolution. As a complementary method, the a-priori knowledge of the sample is employed to identify potential defect sites by analyzing the diffraction patterns. In this method, the recorded diffraction patterns are compared with the die or database data (i.e. previously measured or calculated diffraction data from the defect-free mask layout respectively) and their difference is interpreted as the defect signal. Dynamic software filtering helps to suppress the strong diffraction from defect-free structures and allows registration of faint defects with high sensitivity. Here, we discuss the basic principles of these Fourier domain techniques and its potential for actinic mask inspection with high signal-to-noise ratio and high throughput.

  11. Use of neonatal simulation models to assess competency in bag-mask ventilation.

    PubMed

    Pearlman, S A; Zern, S C; Blackson, T; Ciarlo, J A; Mackley, A B; Locke, R G

    2016-03-01

    Providing adequate bag-mask ventilation (BMV) is an essential skill for neonatal resuscitation. Often this skill is learned using simulation manikins. Currently, there is no means of measuring the adequacy of ventilation in simulated scenarios. Thus, it is not possible to ascertain proficiency. The first aim of this study was to measure the pressure generated during BMV as performed by providers with different skill levels and measure the impact of different feedback mechanisms. The second aim was to measure the pressure volume characteristics of two neonatal manikins to see how closely they reflect newborn lung mechanics. In Phase I to achieve the first aim, we evaluated BMV skills in different level providers including residents (n=5), fellows (n=5), neonatal nurse practitioners (n=5) and neonatologists (n=5). Each provider was required to provide BMV for 2-min epochs on the SimNewB (Laerdal), which had been instrumented to measure pressure-volume characteristics. In sequential 2-min epochs, providers were given different feedback including chest-wall movement alone compared to manometer plus chest-wall movement or chest-wall movement plus manometer plus laptop lung volume depiction. In Phase II of the study we measured pressure-volume characteristics in instrumented versions of the SimNewB (Laerdal) and NeoNatalie (Laerdal). In Phase I, all providers are compared with the neonatologists. All measurements of tidal volume (Vt) are below the desired 5 ml kg(-1). The greatest difference in Vt between the neonatologists and other providers occurs when only chest-wall movement is provided. A linear relationship is noted between Vt and PIP for both SimNewB and NeoNatalie. The compliance curves are not 'S-shaped' and are different between the two models (P<0.001). Phase I of this study demonstrates that the SimNewB with the feedback of chest-wall movement alone was the best method of distinguishing experienced from inexperienced providers during simulated BMV

  12. Modeling the anti-masking effects of the olivocochlear reflex in auditory nerve responses to tones in sustained noise.

    PubMed

    Chintanpalli, Ananthakrishna; Jennings, Skyler G; Heinz, Michael G; Strickland, Elizabeth A

    2012-04-01

    The medial olivocochlear reflex (MOCR) has been hypothesized to provide benefit for listening in noise. Strong physiological support for an anti-masking role for the MOCR has come from the observation that auditory nerve (AN) fibers exhibit reduced firing to sustained noise and increased sensitivity to tones when the MOCR is elicited. The present study extended a well-established computational model for normal-hearing and hearing-impaired AN responses to demonstrate that these anti-masking effects can be accounted for by reducing outer hair cell (OHC) gain, which is a primary effect of the MOCR. Tone responses in noise were examined systematically as a function of tone level, noise level, and OHC gain. Signal detection theory was used to predict detection and discrimination for different spontaneous rate fiber groups. Decreasing OHC gain decreased the sustained noise response and increased maximum discharge rate to the tone, thus modeling the ability of the MOCR to decompress AN fiber rate-level functions. Comparing the present modeling results with previous data from AN fibers in decerebrate cats suggests that the ipsilateral masking noise used in the physiological study may have elicited up to 20 dB of OHC gain reduction in addition to that inferred from the contralateral noise effects. Reducing OHC gain in the model also extended the dynamic range for discrimination over a wide range of background noise levels. For each masker level, an optimal OHC gain reduction was predicted (i.e., where maximum discrimination was achieved without increased detection threshold). These optimal gain reductions increased with masker level and were physiologically realistic. Thus, reducing OHC gain can improve tone-in-noise discrimination even though it may produce a “hearing loss” in quiet. Combining MOCR effects with the sensorineural hearing loss effects already captured by this computational AN model will be beneficial for exploring the implications of their interaction

  13. Compact model experimental validation for grapho-epitaxy hole processes and its impact in mask making tolerances

    NASA Astrophysics Data System (ADS)

    Fenger, Germain; Torres, J. Andres; Ma, Yuansheng; Granik, Yuri; Krasnova, Polina; Fouquet, Antoine; Belledent, Jérôme; Gharbi, Ahmed; Tiron, Raluca

    2014-10-01

    There has been significant research in the area of modeling self-assembling molecular systems. Directed self-assembly (DSA) has proven to be a promising candidate for cost reduction of processes which use double patterning and an enabler of new technology nodes. Self-consistent field theory and Monte Carlo simulators have the capability to probe and explore the mechanisms driving the different phases of a diblock copolymer system. While such methods are appropriate to study the nature of the self-assembly process, they are computationally expensive and they cannot be used to perform mask synthesis operations nor full chip verification. In this case we focus our effort in establishing the minimum set of conditions that a compact model for the manufacture of contact holes using a grapho epitaxy process for a PS-b-PMMA diblock copolymer system needs. The compact model's main objectives are to find the guiding pattern that produces the lowest possible placement error, as well as verifying that the intended target structures are present after processing. Given that masks are not perfect, and lithographic process variations are not negligible, it is necessary to understand the mask requirements and the types of Optical Proximity Correction techniques that will be used to build guiding patterns. This paper explores the guiding pattern conditions under which proper assembly is achieved, and how the compact model formulation is able to determine placement of reliably assembling structures as well as identification of the guiding patterns which lead to improper assembly. The research leading to these results has been performed in the frame of the industrial collaborative consortium IDeAL focused on the development of Directed Self-assembly technique by block copolymers.

  14. Proximity lithography membrane mask aeroelasticity

    NASA Astrophysics Data System (ADS)

    Huston, Dryver; Burns, Dylan; Boerger, Brent; Selzer, Robert

    2006-03-01

    Proximity lithography places a thin membrane mask into close proximity (5-100 micron) to a wafer for exposure to radiation and pattern placement. Efficient production practices require that the wafer be positioned relative to the mask as quickly as possible. The positioning maneuvers involve both a lateral motion and a closing of the mask-to-wafer gap. Gap closing requires forcing the exposure chamber gas (usually air or helium, possibly at a mild vacuum) between the mask and wafer out through the edges of the gap in a squeeze film process that can substantially deflect and damage the membrane mask. Moving laterally, i.e. stepping, would be more efficient if it were performed at the close proximity gap. The buildup of hydrodynamic pressures while stepping at gap can deform and possibly damage the mask. This paper discusses methods to model, measure and control aeroelastic effects due to gap closing and lateral stepping at gap. The analysis considers an aeroelastic model based on coupling Reynolds' hydrodynamic lubrication theory with membrane mechanics. A principal result of the analysis is the prediction that it is possible to step at gap and produce minimal aeroelastic out-of-plane deflections, if the wedge angle is zero, and both the membrane and mask have a flat profile. The aeroelastic models are confirmed with experiments that measure out-of-plane stepping of a membrane versus wedge angle, gap and speed. Non-flat mask profiles, such as buttes and mesas raise additional aeroelastic issues are also examined.

  15. Smoke Mask

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Smoke inhalation injury from the noxious products of fire combustion accounts for as much as 80 percent of fire-related deaths in the United States. Many of these deaths are preventable. Smoke Mask, Inc. (SMI), of Myrtle Beach, South Carolina, is working to decrease these casualties with its line of life safety devices. The SMI personal escape hood and the Guardian Filtration System provide respiratory protection that enables people to escape from hazardous and unsafe conditions. The breathing filter technology utilized in the products is specifically designed to supply breathable air for 20 minutes. In emergencies, 20 minutes can mean the difference between life and death.

  16. NEG (non evaporable getter) pumps for organic compounds and water removal in EUVL tools

    NASA Astrophysics Data System (ADS)

    Conte, A.; Manini, P.; Raimondi, S.

    2008-03-01

    One of present EUVL challenges is to reduce as much as possible the organic compounds and water partial pressures during the lithographic process. These gases can in fact interact with sensitive surfaces and, in the presence of EUV radiation, decompose to generate carbon-based films and oxides, which are detrimental to the optics, reducing its performance, lifetime and significantly increasing the equipment total cost of ownership. With this respect, use of Non Evaporable Getter (NEG) pumps seems particularly attractive. Getter pumps are very clean, vibration-free, compact, able to deliver large pumping speed for all active gases, including water and hydrogen. In the present paper, we report for the first time the results of specific tests aimed at measuring the pumping speed for some selected organic compounds, namely toluene and decane (n-decane). The study shows that getter pumps can effectively sorb these large organic molecules with high speed and capacity. Speed and capacity increases when operating the getter cartridge at moderate temperature (e.g. 150-200°C), however remarkable sorption is achieved, even at room temperature, without any power applied. When coupled with turbo-molecular pumps NEG pumps have therefore the potential to improve the ultimate vacuum and mitigate the carbon/oxygen contamination in a UHV lithographic system.

  17. Dynamic mask for producing uniform or graded-thickness thin films

    DOEpatents

    Folta, James A.

    2006-06-13

    A method for producing single layer or multilayer films with high thickness uniformity or thickness gradients. The method utilizes a moving mask which blocks some of the flux from a sputter target or evaporation source before it deposits on a substrate. The velocity and position of the mask is computer controlled to precisely tailor the film thickness distribution. The method is applicable to any type of vapor deposition system, but is particularly useful for ion beam sputter deposition and evaporation deposition; and enables a high degree of uniformity for ion beam deposition, even for near-normal incidence of deposition species, which may be critical for producing low-defect multilayer coatings, such as required for masks for extreme ultraviolet lithography (EUVL). The mask can have a variety of shapes, from a simple solid paddle shape to a larger mask with a shaped hole through which the flux passes. The motion of the mask can be linear or rotational, and the mask can be moved to make single or multiple passes in front of the substrate per layer, and can pass completely or partially across the substrate.

  18. Analysis of process margin in EUV mask repair with nano-machining

    NASA Astrophysics Data System (ADS)

    Lee, Su-Young; Kim, Geun-Bae; Sim, Hong-Seok; Lee, Sang-Hyeon; Kim, Hwa-Sung; Lee, Jung-Hwan; Seo, Hwan-Seok; Han, Hak-Seung; Kim, Seong-Sue; Moon, Seong-Yong; Woo, Sang-Gyun; Bozak, Ron; Dinsdale, Andrew; Robinson, Tod; Lee, David; Cho, HanKu

    2008-10-01

    Reduced design rules demand higher sensitivity of inspection, and thus small defects which did not affect printability before require repair now. The trend is expected to be similar in extreme ultraviolet lithography (EUVL) which is a promising candidate for sub 32 nm node devices due to high printing resolution. The appropriate repair tool for the small defects is a nanomachining system. An area which remains to be studied is the nano-machining system performance regarding repair of the defects without causing multilayer damage. Currently, nanomachining Z-depth controllability is 3 nm while the Ru-capping layer is 2.5 nm thick in a Buffer-less Ru-capped EUV mask. For this report, new repair processes are studied in conjunction with the machining behavior of the different EUVL mask layers. Repair applications to achieve the Edge Placement(EP) and Z-depth controllability for an optimal printability process window are discussed. Repair feasibility was determined using a EUV micro exposure tool (MET) and Actinic Imaging Tool (AIT) to evaluate repairs the 30 nm and 40 nm nodes. Finally, we will report the process margin of the repair through Slitho-EUVTM simulation by controlling side wall angle, Z-depth, and EP (Edge Placement) on the base of 3-dimensional experimental result.

  19. Commercial EUV mask blank readiness for 32 nm HP manufacturing

    NASA Astrophysics Data System (ADS)

    Seidel, Phil

    2007-05-01

    Successful commercialization of extreme ultraviolet lithography (EUVL) requires high quality EUV mask blanks for patterned masks that are essentially defect-free and very flat with high performance reflective multilayers. For 32 nm half-pitch (HP) integrated circuit manufacturing, such blanks require zero defects down to 25 nm diameter sizes while simultaneously meeting other specifications. At least three critical specifications that need continued improvements (total defects, defect size inspection, and substrate flatness control) are challenging to attain individually; meeting all requirements simultaneously will be especially challenging. Since early 2003, SEMATECH has been engaged with the mask blank materials and mask tool supplier community to drive the readiness of alpha, beta, and production mask blanks to support EUV lithography introduction. SEMATECH uses its commercial mask blank development roadmap together with neutral metrology evaluations of commercial suppliers' materials to monitor progress against needed production requirements. Commercial blank capability has improved significantly over the past two years; however, beta-level performance has still not been attained for all requirements. Attaining integrated blank specifications is more difficult than meeting individual specifications. Significant improvements including defectivity, flatness, coefficient of thermal expansion (CTE), reflectivity, wavelength control, and buffer/absorber stack performances are needed. Several orders of magnitude improvement is needed in defectivity levels alone coupled with increased detection sensitivity to 25 nm diameter defects. This paper will illustrate the recent rate of improvements along with an updated SEMATECH commercial roadmap, highlighting individual specification performances and total blank integrated performance levels currently better than 0.2 def/cm2 at >= 80 nm polystyrene latex (PSL), peak reflectivity >= 64.0%, substrate flatnesses <= 175 nm

  20. Masks: Interpretations and Variations.

    ERIC Educational Resources Information Center

    Basso, Robert

    1990-01-01

    Presents a high school art teacher's views of and experiences with masks. Outlines a maskmaking activity in which students were required to create variations on existing masks. Emphasizes use of experimental materials. Displays examples of student-created masks. (DB)

  1. Development of a Model to Assess Masking Potential for Marine Mammals by the Use of Air Guns in Antarctic Waters.

    PubMed

    Wittekind, Dietrich; Tougaard, Jakob; Stilz, Peter; Dähne, Michael; Clark, Christopher W; Lucke, Klaus; von Benda-Beckmann, Sander; Ainslie, Michael A; Siebert, Ursula

    2016-01-01

    We estimated the long-range effects of air gun array noise on marine mammal communication ranges in the Southern Ocean. Air gun impulses are subject to significant distortion during propagation, potentially resulting in a quasi-continuous sound. Propagation modeling to estimate the received waveform was conducted. A leaky integrator was used as a hearing model to assess communication masking in three species due to intermittent/continuous air gun sounds. Air gun noise is most probably changing from impulse to continuous noise between 1,000 and 2,000 km from the source, leading to a reduced communication range for, e.g., blue and fin whales up to 2,000 km from the source.

  2. Enhancing EUV mask blanks usability through smart shift and blank-design pairing optimization

    NASA Astrophysics Data System (ADS)

    Soni, Rakesh Kumar; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter; Thwaite, Peter

    2016-10-01

    EUV Defect avoidance techniques will play a vital role in extreme ultraviolet lithography (EUVL) photomask fabrication with the anticipation that defect free mask blanks won't be available and that cost effective techniques will not be available for defect repairing. In addition, mask shops may not have a large inventory of expensive EUV mask blanks. Given these facts, defect avoidance can be used as cost effective technique to optimize the mask blank and design data (mask data) pair selection across mask blank manufacturers and mask shops so that overall mask blank utilization can be enhanced. In previous work, it was determined that the pattern shift based solution increases the chance that a defective mask blank can be used that would otherwise be discarded [1]. In pattern shift, design data is shifted such that defects are either moved to isolated regions or hidden under the patterns that are written. However pattern shifts techniques don't perform well with masks with higher defect counts. Pattern shift techniques in this form assume all defects to be equally critical. In addition, a defect is critical or important only if it lands on the main pattern. A defect landing on fill, sub-resolution assist feature (SRAF) or fiducial areas may not be critical. In this paper we assess the performance of pattern shift techniques assuming defects that are not critical based upon size or type, as well as defects landing in non-critical areas (smart shift) can be ignored. In a production mask manufacturing environment it is necessary to co-optimize and prioritize blank-design pairing for multiple mask layouts in the queue with the available blanks. A blank-design pairing tool maximizes the utilization of blanks by finding the best pairing between blanks and design data so that the maximum number of mask blanks can be used. In this paper we also propose a novel process which would optimize the usage of costly EUV mask blanks across mask blank manufacturers and mask shops

  3. Masks and Other Disguises.

    ERIC Educational Resources Information Center

    Ploghoft, Debra

    Instructions for making simple masks are provided in this guide for teachers of elementary children. Directions with illustrations are given for constructing masks from paper plates, construction paper, plastic milk jugs, and papier-mache. Ideas include a clown mask, a flower mask, a top hat, a paper crown, and "Groucho" glasses. Types…

  4. Masks and Other Disguises.

    ERIC Educational Resources Information Center

    Ploghoft, Debra

    Instructions for making simple masks are provided in this guide for teachers of elementary children. Directions with illustrations are given for constructing masks from paper plates, construction paper, plastic milk jugs, and papier-mache. Ideas include a clown mask, a flower mask, a top hat, a paper crown, and "Groucho" glasses. Types…

  5. Improving Approaches for Determining Ice Volume Change on the Greenland Ice Sheet Margin using ASTER and SPOT Digital Elevation Models and Spectral Masking

    NASA Astrophysics Data System (ADS)

    Johnson, K. N.; Rhodes, T.; Tulaczyk, S. M.; Finfrock, A.; Lajoie, L.

    2009-12-01

    The Greenland Ice Sheet (GIS) is the largest ice sheet in the Northern Hemisphere and understanding trends in its mass balance has important implications for predicting global sea level rise. High relief topography along the margin of the GIS makes it difficult to use low-resolution remote sensing to resolve ice elevations. These marginal regions however, tend to be more dynamic than the interior of the ice sheet and may show signs of ice volume loss earlier than the interior. In this study we difference georeferenced ASTER digital elevation models (DEMs) from 2000-01 (30 meter resolution) with SPOT DEMs from 2008-09 (40 meter resolution) made available through the SPIRIT IPY program. ASTER DEMs from 2006-07 are used where SPOT data is not available. The change in these DEMs is divided by the time elapsed between scenes giving change in km3 per year. The method used for DEM production is not accurate over low contrast surfaces such as water, and snow. High relief bedrock can also have more error than areas of glacial ice due to slope. Masking snow, water, and rock from scenes minimizes total error. Most methods of spectral masking available in the literature rely on establishing thresholds for a scene which separate snow from ice from water. In order to apply these methods to multiple scenes taken at different latitudes, seasons, and sun altitudes, a new set of thresholds need to be developed for each scene which proves to be a very time intensive process. When covering large areas with a mosaic of scenes, these methods have not proven applicable. We have developed a method of nesting masks which allows for faster and less subjective trial-and-error threshold setting. This method can be applied to a range of scenes with little to no individual manipulation giving a repeatable result. The first mask eliminates most bedrock with a negative NDSI and fjord water and sea ice with an elevation of about 0. A principal components analysis (PCA) is done under this mask for

  6. History and future of mask making

    NASA Astrophysics Data System (ADS)

    Levy, Ken L.

    1996-12-01

    The history of the mask industry has three main periods, which I call the Classical Period, the Dark Ages, and the Renaissance, by analogy with those periods in the history of Western Europe. During the Classical Period, people developed 1X masks and the technology to make them. In the Dark Ages, people exploited the equipment developed during the Classical Period to make 5X reduction reticle, ending the nobility of mask making. In today's Renaissance of mask making, a proliferation of mask types is requiring a rebirth of innovation and creativity. The Renaissance resembles the Classical Period: masks are once again strategic, and technological capability is once again the driver. Meanwhile, the mask industry is carrying forward the productivity and efficiency gains it achieved during the Dark Ages. We must create a new business and economic model to support these changes in the characteristics of the marketplace.

  7. A computational feedforward model predicts categorization of masked emotional body language for longer, but not for shorter, latencies.

    PubMed

    Stienen, Bernard M C; Schindler, Konrad; de Gelder, Beatrice

    2012-07-01

    Given the presence of massive feedback loops in brain networks, it is difficult to disentangle the contribution of feedforward and feedback processing to the recognition of visual stimuli, in this case, of emotional body expressions. The aim of the work presented in this letter is to shed light on how well feedforward processing explains rapid categorization of this important class of stimuli. By means of parametric masking, it may be possible to control the contribution of feedback activity in human participants. A close comparison is presented between human recognition performance and the performance of a computational neural model that exclusively modeled feedforward processing and was engineered to fulfill the computational requirements of recognition. Results show that the longer the stimulus onset asynchrony (SOA), the closer the performance of the human participants was to the values predicted by the model, with an optimum at an SOA of 100 ms. At short SOA latencies, human performance deteriorated, but the categorization of the emotional expressions was still above baseline. The data suggest that, although theoretically, feedback arising from inferotemporal cortex is likely to be blocked when the SOA is 100 ms, human participants still seem to rely on more local visual feedback processing to equal the model's performance.

  8. LER control and mitigation: mask roughness induced LER

    SciTech Connect

    McClinton, Brittany; Naulleau, Patrick

    2011-02-21

    In the push towards commercialization of extreme-ultraviolet lithography (EUVL), meeting the stringent requirements for line-edge roughness (LER) is increasingly challenging. For the 22-nm half-pitch node and below, the ITRS requires under 1.2 nm LER. Much of this LER is thought to arise from three significant contributors: LER on the mask absorber pattern, LER from the resist, and LER from mask roughness induced speckle. The physical mechanism behind the last contributor is becoming clearer, but how it is affected by the presence of aberrations is less well understood. Here, we conduct a full 2D aerial image simulation analysis of aberrations sensitivities of mask roughness induced LER for the first 37 fringe zernikes. These results serve as a guideline for future LER aberrations control. In examining how to mitigate mask roughness induced LER, we next consider an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a 'strip'. While this illumination surprisingly provides merely minimal improvement to the LER as several alternate illumination schemes, overall imaging quality in terms of ILS, NILS, and contrast is improved. While the 22-nm half-pitch node can tolerate significant aberrations from a mask roughness induced LER perspective, total aberration levels for the 16-nm half-pitch node need to be strictly capped at 0.25nm rms to meet the ITRS guidelines. An individual aberrations study for the first 37 fringe zernikes on the 16-nm half-pitch node at the 0.25nm rms level reveals a sensitivity to various forms of spherical aberrations (Z9 & Z25) and quadrafoil (Z28) in particular, under conventional crosspole illumination ({sigma} = 0.10). Compared to conventional dipole or crosspole illuminations, an extended dipole 'strip' illumination scheme offers a way to mitigate mask roughness induced LER, while still maintaining high imaging quality for

  9. Damage Free Particle Removal from Extreme Ultraviolet Lithography Mask Layers by High Energy Laser Shock Wave Cleaning

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Gon; Yoo, Young-Sam; Kim, Tae-Geun; Ahn, Jinho; Lee, Jong-Myoung; Choi, Jae-Sung; Busnaina, Ahmed A.; Park, Jin-Goo

    2008-06-01

    Plasma shock waves induced by focusing a Q-switched Nd:YAG laser at a maximum energy of 1.8 J in air were characterized by a laser beam deflection method and were applied to 50 nm silica particle removal from a Al2O3/TaN/Ru/MoSi 40 pairs as the extreme ultraviolet lithography (EUVL) mask layers on silicon wafer. A high energy laser induced shock wave effectively removed 50 nm silica particles from the EUVL mask layers. The change of sample topography before and after laser shock cleaning was measured by an atomic force microscope. Surface damage was observed at a gap distance of 1.5 mm. The dimensions of the plasma plume were characterized as a function of the laser energy and focus-to-surface gap distance. The plasma plume was the main source for damaging the surface. A high energy laser induced shock wave with a gap distance of over 3 mm achieved damage-free sub-100 nm particle removal.

  10. EUV mask defectivity - a process of increasing control toward HVM

    NASA Astrophysics Data System (ADS)

    Jonckheere, Rik

    2017-06-01

    This article covers the various aspects of defectivity of a typical mask used for extreme ultra-violet (EUV) lithography. The focus of the present article is on those aspects that are more specific for EUV lithography. A prime type of defect that fully falls under the really EUV-specific category consists of the so-called multilayer defects (ML-defects): these defects relate to the ML mirror on the mask, which makes it reflective. While not specific, particle contamination plays a special role in EUV lithography and includes two aspects: both front- and backside of an EUV mask have peculiarities beyond historical deep-UV lithography. Frontside particles can print when they exceed a critical size and, while solvable as in (deep)-UV lithography by means of a pellicle, there are specific challenges. Backside particles can distort a clamped EUV reticle, and the resulting local non-flatness of the reticle may result in focus and overlay errors on the wafer. A last aspect that requires special attention for EUVL can be categorized under reticle degradation by extensive use. That includes the high-volume manufacturing-oriented conditions of high source power needed to obtain competitive throughput. For each aspect of EUV mask defectivity, and hence each type of defect, the paper reviews how the community tackles them and how their possible impact on the result of wafer printing with a given EUV reticle is minimized. This includes a summary of the authors' own contribution to related learning and developments. Finally, a personal interpretation is given of what are the remaining open items before a workable or full solution can be considered in place.

  11. Variations in backward masking with different masking stimuli: I. Local interaction versus attentional switch.

    PubMed

    Bachmann, Talis; Luiga, Iiris; Põder, Endel

    2005-01-01

    The types of stimuli used as targets and masks considerably change the masking functions in a way that requires us to abandon any single mechanism of masking as the sole explanation of backward masking. In the first of two reports in which the problem of the mask-dependence of masking is addressed, we explore the role of the relative spatial positioning of targets and masks in order to differentiate between local interaction and attentional models. If single letters were masked by double-letter masks then the relative spatial arrangement of the letters, which was changed in order to vary the involvement of metacontrast-like processes, had an effect at shorter SOAs, but not at longer SOAs where strong masking still persisted. This poses difficulties for proposing local contour interaction as the main mechanism of masking. Similarly, crowding effects alone cannot explain the results. Backward masking also involves attention being directed to working-memory processing of the succeeding object while abandoning the preceding object.

  12. 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.

  13. Masking the Color Wheel.

    ERIC Educational Resources Information Center

    Greene, Charlene

    1982-01-01

    Describes an art activity in which sixth graders made mirror-image masks using only two primary colors and one secondary color. Students discussed the effect of color combinations and the use of masks in folk and modern cultures. (AM)

  14. Noise masking of White's illusion exposes the weakness of current spatial filtering models of lightness perception.

    PubMed

    Betz, Torsten; Shapley, Robert; Wichmann, Felix A; Maertens, Marianne

    2015-01-01

    Spatial filtering models are currently a widely accepted mechanistic account of human lightness perception. Their popularity can be ascribed to two reasons: They correctly predict how human observers perceive a variety of lightness illusions, and the processing steps involved in the models bear an apparent resemblance with known physiological mechanisms at early stages of visual processing. Here, we tested the adequacy of these models by probing their response to stimuli that have been modified by adding narrowband noise. Psychophysically, it has been shown that noise in the range of one to five cycles per degree (cpd) can drastically reduce the strength of some lightness phenomena, while noise outside this range has little or no effect on perceived lightness. Choosing White's illusion (White, 1979) as a test case, we replicated and extended the psychophysical results, and found that none of the spatial filtering models tested was able to reproduce the spatial frequency specific effect of narrowband noise. We discuss the reasons for failure for each model individually, but we argue that the failure is indicative of the general inadequacy of this class of spatial filtering models. Given the present evidence we do not believe that spatial filtering models capture the mechanisms that are responsible for producing many of the lightness phenomena observed in human perception. Instead we think that our findings support the idea that low-level contributions to perceived lightness are primarily determined by the luminance contrast at surface boundaries.

  15. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

    Art is a good place to learn about our multicultural planet, and African masks are prized throughout the world as powerfully expressive artistic images. Unfortunately, multicultural education, especially for young children, can perpetuate stereotypes. Masks taken out of context lose their meaning and the term "African masks" suggests that there is…

  16. Masks in Pedagogical Practice

    ERIC Educational Resources Information Center

    Roy, David

    2016-01-01

    In Drama Education mask work is undertaken and presented as both a methodology and knowledge base. There are numerous workshops and journal articles available for teachers that offer knowledge or implementation of mask work. However, empirical examination of the context or potential implementation of masks as a pedagogical tool remains…

  17. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

    Art is a good place to learn about our multicultural planet, and African masks are prized throughout the world as powerfully expressive artistic images. Unfortunately, multicultural education, especially for young children, can perpetuate stereotypes. Masks taken out of context lose their meaning and the term "African masks" suggests that there is…

  18. 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

  19. Mask degradation monitoring with aerial mask inspector

    NASA Astrophysics Data System (ADS)

    Tseng, Wen-Jui; Fu, Yung-Ying; Lu, Shih-Ping; Jiang, Ming-Sian; Lin, Jeffrey; Wu, Clare; Lifschitz, Sivan; Tam, Aviram

    2013-06-01

    As design rule continues to shrink, microlithography is becoming more challenging and the photomasks need to comply with high scanner laser energy, low CDU, and ever more aggressive RETs. This give rise to numerous challenges in the semiconductor wafer fabrication plants. Some of these challenges being contamination (mainly haze and particles), mask pattern degradation (MoSi oxidation, chrome migration, etc.) and pellicle degradation. Fabs are constantly working to establish an efficient methodology to manage these challenges mainly using mask inspection, wafer inspection, SEM review and CD SEMs. Aerial technology offers a unique opportunity to address the above mask related challenges using one tool. The Applied Materials Aera3TM system has the inherent ability to inspect for defects (haze, particles, etc.), and track mask degradation (e.g. CDU). This paper focuses on haze monitoring, which is still a significant challenge in semiconductor manufacturing, and mask degradation effects that are starting to emerge as the next challenge for high volume semiconductor manufacturers. The paper describes Aerial inspector (Aera3) early haze methodology and mask degradation tracking related to high volume manufacturing. These will be demonstrated on memory products. At the end of the paper we take a brief look on subsequent work currently conducted on the more general issue of photo mask degradation monitoring by means of an Aerial inspector.

  20. Wafer topography modeling for ionic implantation mask correction dedicated to 2x nm FDSOI technologies

    NASA Astrophysics Data System (ADS)

    Michel, Jean-Christophe; Le Denmat, Jean-Christophe; Sungauer, Elodie; Robert, Frédéric; Yesilada, Emek; Armeanu, Ana-Maria; Entradas, Jorge; Sturtevant, John L.; Do, Thuy; Granik, Yuri

    2013-04-01

    Reflection by wafer topography and underlying layers during optical lithography can cause unwanted exposure in the resist [1]. This wafer stack effect phenomenon which is neglected for larger nodes than 45nm, is becoming problematic for 32nm technology node and below at the ionic implantation process. This phenomenon is expected to be attenuated by the use of anti-reflecting coating but increases process complexity and adds cost and cycle time penalty. As a consequence, an OPC based solution is today under evaluation to cope with stack effects involved in ionic implantation patterning [2] [3]. For the source drain (SD) ionic implantation process step on 28nm Fully Depleted Silicon-on-Insulator (FDSOI) technology, active silicon areas, poly silicon patterns, Shallow Trench Isolation (STI), Silicon-on-Insulator (SOI) areas and the transitions between these different regions result in significant SD implant pattern critical dimension variations. The large number of stack variations involved in these effects implies a complex modeling to simulate pattern degradations. This paper deals with the characterization of stack effects on 28nm node using SOI substrates. The large number of measurements allows to highlight all individual and combined stack effects. A new modeling flow has been developed in order to generate wafer stack aware OPC model. The accuracy and the prediction of the model is presented in this paper.

  1. Detecting Drawdowns Masked by Environmental Stresses with Water-Level Models

    PubMed Central

    Garcia, CA; Halford, KJ; Fenelon, JM

    2013-01-01

    Detecting and quantifying small drawdown at observation wells distant from the pumping well greatly expands the characterized aquifer volume. However, this detection is often obscured by water level fluctuations such as barometric and tidal effects. A reliable analytical approach for distinguishing drawdown from nonpumping water-level fluctuations is presented and tested here. Drawdown is distinguished by analytically simulating all pumping and nonpumping water-level stresses simultaneously during the period of record. Pumping signals are generated with Theis models, where the pumping schedule is translated into water-level change with the Theis solution. This approach closely matched drawdowns simulated with a complex three-dimensional, hypothetical model and reasonably estimated drawdowns from an aquifer test conducted in a complex hydrogeologic system. Pumping-induced changes generated with a numerical model and analytical Theis model agreed (RMS as low as 0.007 m) in cases where pumping signals traveled more than 1 km across confining units and fault structures. Maximum drawdowns of about 0.05 m were analytically estimated from field investigations where environmental fluctuations approached 0.2 m during the analysis period. PMID:23469925

  2. Detecting drawdowns masked by environmental stresses with water-level models

    USGS Publications Warehouse

    Garcia, C.A.; Halford, K.J.; Fenelon, J.M.

    2013-01-01

    Detecting and quantifying small drawdown at observation wells distant from the pumping well greatly expands the characterized aquifer volume. However, this detection is often obscured by water level fluctuations such as barometric and tidal effects. A reliable analytical approach for distinguishing drawdown from nonpumping water-level fluctuations is presented and tested here. Drawdown is distinguished by analytically simulating all pumping and nonpumping water-level stresses simultaneously during the period of record. Pumping signals are generated with Theis models, where the pumping schedule is translated into water-level change with the Theis solution. This approach closely matched drawdowns simulated with a complex three-dimensional, hypothetical model and reasonably estimated drawdowns from an aquifer test conducted in a complex hydrogeologic system. Pumping-induced changes generated with a numerical model and analytical Theis model agreed (RMS as low as 0.007 m) in cases where pumping signals traveled more than 1 km across confining units and fault structures. Maximum drawdowns of about 0.05 m were analytically estimated from field investigations where environmental fluctuations approached 0.2 m during the analysis period.

  3. Cognitive Development Masks Support for Attributional Style Models of Depression in Children and Adolescents

    ERIC Educational Resources Information Center

    Weitlauf, Amy S.; Cole, David A.

    2012-01-01

    Attributional style models of depression in adults (Abramson et al. 1989, 1978) have been adapted for use with children; however, most applications do not consider that children's understanding of causal relations may be qualitatively different from that of adults. If children's causal attributions depend on children's level of cognitive…

  4. 2013 mask industry survey

    NASA Astrophysics Data System (ADS)

    Malloy, Matt

    2013-09-01

    A comprehensive survey was sent to merchant and captive mask shops to gather information about the mask industry as an objective assessment of its overall condition. 2013 marks the 12th consecutive year for this process. Historical topics including general mask profile, mask processing, data and write time, yield and yield loss, delivery times, maintenance, and returns were included and new topics were added. Within each category are multiple questions that result in a detailed profile of both the business and technical status of the mask industry. While each year's survey includes minor updates based on feedback from past years and the need to collect additional data on key topics, the bulk of the survey and reporting structure have remained relatively constant. A series of improvements is being phased in beginning in 2013 to add value to a wider audience, while at the same time retaining the historical content required for trend analyses of the traditional metrics. Additions in 2013 include topics such as top challenges, future concerns, and additional details in key aspects of mask masking, such as the number of masks per mask set per ground rule, minimum mask resolution shipped, and yield by ground rule. These expansions beyond the historical topics are aimed at identifying common issues, gaps, and needs. They will also provide a better understanding of real-life mask requirements and capabilities for comparison to the International Technology Roadmap for Semiconductors (ITRS).

  5. Study on modeling of resist heating effect correction in EB mask writer EBM-9000

    NASA Astrophysics Data System (ADS)

    Nomura, Haruyuki; Kamikubo, Takashi; Suganuma, Mizuna; Kato, Yasuo; Yashima, Jun; Nakayamada, Noriaki; Anze, Hirohito; Ogasawara, Munehiro

    2015-07-01

    Resist heating effect which is caused in electron beam lithography by rise in substrate temperature of a few tens or hundreds of degrees changes resist sensitivity and leads to degradation of local critical dimension uniformity (LCDU). Increasing writing pass count and reducing dose per pass is one way to avoid the resist heating effect, but it worsens writing throughput. As an alternative way, NuFlare Technology is developing a heating effect correction system which corrects CD deviation induced by resist heating effect and mitigates LCDU degradation even in high dose per pass conditions. Our developing correction model is based on a dose modulation method. Therefore, a kind of conversion equation to modify the dose corresponding to CD change by temperature rise is necessary. For this purpose, a CD variation model depending on local pattern density was introduced and its validity was confirmed by experiments and temperature simulations. And then the dose modulation rate which is a parameter to be used in the heating effect correction system was defined as ideally irrelevant to the local pattern density, and the actual values were also determined with the experimental results for several resist types. The accuracy of the heating effect correction was also discussed. Even when deviations depending on the pattern density slightly remains in the dose modulation rates (i.e., not ideal in actual), the estimated residual errors in the correction are sufficiently small and acceptable for practical 2 pass writing with the constant dose modulation rates. In these results, it is demonstrated that the CD variation model is effective for the heating effect correction system.

  6. Validity of the thin mask approximation in extreme ultraviolet mask roughness simulations

    SciTech Connect

    Naulleau, Patrick; George, Simi

    2011-01-26

    In the case of extreme ultraviolet (EUV) lithography, modeling has shown that reflector phase roughness on the lithographic mask is a significant concern due to the image plan speckle it causes and the resulting line-edge roughness on imaged features. Modeling results have recently been used to determine the requirements for future production worthy masks yielding the extremely stringent specification of 50 pm rms roughness. Owing to the scale of the problem in terms of memory requirements, past modeling results have all been based on the thin mask approximation. EUV masks, however, are inherently three dimensional in nature and thus the question arises as to the validity of the thin mask approximation. Here we directly compare image plane speckle calculation results using the fast two dimensional thin mask model to rigorous finite-difference time-domain results and find the two methods to be comparable.

  7. Vendor Capability for Low Thermal Expansion Mask Substrates for EUV Lithography

    SciTech Connect

    Blaedel, K L; Taylor, J S; Hector, S D; Yan, P Y; Ramamoorthy, A; Brooker, P D

    2002-04-12

    Development of manufacturing infrastructure is required to ensure a commercial source of mask substrates for the timely introduction of EUVL. Improvements to the low thermal expansion materials that compose the substrate have been made, but need to be scaled to production quantities. We have been evaluating three challenging substrate characteristics to determine the state of the infrastructure for the finishing of substrates. First, surface roughness is on track and little risk is associated with achieving the roughness requirement as an independent specification. Second, with new flatness-measuring equipment just coming on line, the vendors are poised for improvement toward the SEMI P37 flatness specification. Third, significant acceleration is needed in the reduction of defect levels on substrates. The lack of high-sensitivity defect metrology at the vendors' sites is limiting progress in developing substrates for EWL.

  8. Effects of biotic interactions on modeled species' distribution can be masked by environmental gradients.

    PubMed

    Godsoe, William; Franklin, Janet; Blanchet, F Guillaume

    2017-01-01

    A fundamental goal of ecology is to understand the determinants of species' distributions (i.e., the set of locations where a species is present). Competition among species (i.e., interactions among species that harms each of the species involved) is common in nature and it would be tremendously useful to quantify its effects on species' distributions. An approach to studying the large-scale effects of competition or other biotic interactions is to fit species' distributions models (SDMs) and assess the effect of competitors on the distribution and abundance of the species of interest. It is often difficult to validate the accuracy of this approach with available data. Here, we simulate virtual species that experience competition. In these simulated datasets, we can unambiguously identify the effects that competition has on a species' distribution. We then fit SDMs to the simulated datasets and test whether we can use the outputs of the SDMs to infer the true effect of competition in each simulated dataset. In our simulations, the abiotic environment influenced the effects of competition. Thus, our SDMs often inferred that the abiotic environment was a strong predictor of species abundance, even when the species' distribution was strongly affected by competition. The severity of this problem depended on whether the competitor excluded the focal species from highly suitable sites or marginally suitable sites. Our results highlight how correlations between biotic interactions and the abiotic environment make it difficult to infer the effects of competition using SDMs.

  9. Video modelling for reducing anxiety related to the use of nasal masks place it for inhalation sedation: a randomised clinical trial.

    PubMed

    Al-Namankany, A; Petrie, A; Ashley, P

    2015-02-01

    A randomised controlled trial to investigate if video modelling can reduce the level of dental anxiety and increase the patient's acceptance of the nasal mask usage for children receiving dental treatment using inhalation sedation (IS). A sample of 80 (8-16 years) children due to have dental treatments under IS were randomly allocated to either the modelling video or the control video (oral hygiene instruction). The level of anxiety was recorded before and after watching the video on the Abeer Children Dental Anxiety Scale and each child's ability to cope with the subsequent procedure was assessed on the visual analogue scale. A two-group Chi-square test was used as the basis for the sample size calculation; a significance level of 0.025 was chosen rather than the conventional 0.05 to avoid spurious results arising from multiple testing. Children in the test group had significantly less anxiety after watching the video than those in the control group throughout the subsequent dental procedure; particullary, at the time of the nasal mask administration (P<0.001). Video modelling appeared to be effective at reducing dental anxiety and has a significant impact on the acceptance of the nasal mask administration for Inhalation Sedation in children.

  10. Aperture masking interferometry research simulation

    NASA Astrophysics Data System (ADS)

    Wang, Haitao; Luo, Qiufeng; Fan, Weijun; Zhang, Xian Ling; Tao, Chunkan; Zhu, Yongtian; Zhou, Bifang; Chen, Hanliang

    2004-10-01

    Aperture Masking Interferometry (AMI) is one of the high-resolution astronomical image observation technologies. It is also an important research way to the Optical Aperture Synthesis (OAS). The theory of OAS is simply introduced and AMI simulation method is raised. The mathematics model is built and the interferogram fringes are got. The aperture mask u-v coverage is discussed and one image reconstruction method is done. The reconstructed image result is got with CLEAN method. Shortcoming of this work is also referred and the future research work is mentioned at last.

  11. Psychometric functions for informational masking

    NASA Astrophysics Data System (ADS)

    Lutfi, Robert A.; Kistler, Doris J.; Callahan, Michael R.; Wightman, Frederic L.

    2003-12-01

    The term informational masking has traditionally been used to refer to elevations in signal threshold resulting from masker uncertainty. In the present study, the method of constant stimuli was used to obtain complete psychometric functions (PFs) from 44 normal-hearing listeners in conditions known to produce varying amounts of informational masking. The listener's task was to detect a pure-tone signal in the presence of a broadband noise masker (low masker uncertainty) and in the presence of multitone maskers with frequencies and amplitudes that varied at random from one presentation to the next (high masker uncertainty). Relative to the broadband noise condition, significant reductions were observed in both the slope and the upper asymptote of the PF for multitone maskers producing large amounts of informational masking. Slope was affected more for some listeners and conditions while asymptote was affected more for others; consequently, neither parameter alone was highly predictive of individual thresholds or the amount of informational masking. Mean slopes and asymptotes varied nonmonotonically with the number of masker components in a manner similar to mean thresholds, particularly when the estimated effect of energetic masking on thresholds was subtracted out. As in past studies, the threshold data were well described by a model in which trial-by-trial judgments are based on a weighted sum of levels in dB at the output of independent auditory filters. The psychometric data, however, complicated the model's interpretation in two ways: First, they suggested that, depending on the listener and condition, the weights can either reflect a fixed influence of masker components on each trial or the effect of occasionally mistaking a masker component for the signal from trial to trial. Second, they indicated that in either case the variance of the underlying decision variable as estimated from PF slope is not by itself great enough to account for the observed changes

  12. Mask industry assessment: 2003

    NASA Astrophysics Data System (ADS)

    Kimmel, Kurt R.

    2003-12-01

    Microelectronics industry leaders routinely name mask technology and mask supply issues of cost and cycle time as top issues of concern. A survey was initiated in 2002 with support from International SEMATECH (ISMT) and administered by SEMI North America to gather information about the mask industry as an objective assessment of its overall condition.1 This paper presents the results of the second annual survey which is an enhanced version of the inaugural survey building upon its strengths and improving the weak points. The original survey was designed with the input of member company mask technologists, merchant mask suppliers, and industry equipment makers. The assessment is intended to be used as a baseline for the mask industry and the microelectronics industry to gain a perspective on the technical and business status of the critical mask industry. An objective is to create a valuable reference to identify strengths and opportunities and to guide investments on critical-path issues. As subsequent years are added, historical profiles can also be created. This assessment includes inputs from ten major global merchant and captive mask manufacturers representing approximately 80% of the global mask market (using revenue as the measure) and making this the most comprehensive mask industry survey ever. The participating companies are: Compugraphics, Dai Nippon Printing, Dupont Photomask, Hoya, IBM, Infineon, Intel, Taiwan Mask Company, Toppan, and TSMC. Questions are grouped into five categories: General Business Profile Information; Data Processing; Yields and Yield loss Mechanisms; Delivery Time; and Returns and Services. Within each category are a multitude of questions that create a detailed profile of both the business and technical status of the mask industry.

  13. Psychometric functions for informational masking

    PubMed Central

    Lutfi, Robert A.; Kistler, Doris J.; Callahan, Michael R.; Wightman, Frederic L.

    2010-01-01

    The term informational masking has traditionally been used to refer to elevations in signal threshold resulting from masker uncertainty. In the present study, the method of constant stimuli was used to obtain complete psychometric functions (PFs) from 44 normal-hearing listeners in conditions known to produce varying amounts of informational masking. The listener’s task was to detect a pure-tone signal in the presence of a broadband noise masker (low masker uncertainty) and in the presence of multitone maskers with frequencies and amplitudes that varied at random from one presentation to the next (high masker uncertainty). Relative to the broadband noise condition, significant reductions were observed in both the slope and the upper asymptote of the PF for multitone maskers producing large amounts of informational masking. Slope was affected more for some listeners and conditions while asymptote was affected more for others; consequently, neither parameter alone was highly predictive of individual thresholds or the amount of informational masking. Mean slopes and asymptotes varied nonmonotonically with the number of masker components in a manner similar to mean thresholds, particularly when the estimated effect of energetic masking on thresholds was subtracted out. As in past studies, the threshold data were well described by a model in which trial-by-trial judgments are based on a weighted sum of levels in dB at the output of independent auditory filters. The psychometric data, however, complicated the model’s interpretation in two ways: First, they suggested that, depending on the listener and condition, the weights can either reflect a fixed influence of masker components on each trial or the effect of occasionally mistaking a masker component for the signal from trial to trial. Second, they indicated that in either case the variance of the underlying decision variable as estimated from PF slope is not by itself great enough to account for the observed

  14. Mitigation of image contrast loss due to mask-side non-telecentricity in an EUV scanner

    NASA Astrophysics Data System (ADS)

    Shih, Chih-Tsung; Yu, Shinn-Sheng; Lu, Yen-Cheng; Chung, Chia-Chun; Chen, Jack J. H.; Yen, Anthony

    2015-03-01

    Due to the use of reflective optics in extreme-ultraviolet lithography (EUVL), the chief ray angle of incidence at the object (mask) side (CRAO) cannot be zero. If the conventional resolution enhancement technique (RET) of off-axis illumination (OAI) is used, such mask-side non-telecentricity degrades aerial image contrast partly because of asymmetry (w.r.t. the mask) of the two beams in an incident beam pair and partly because of asymmetry (w.r.t. the mask) of the two diffraction orders of either incident beam. The former leads to intensity imbalance of the two incident beams (after leaving the mask) and the latter leads to amplitude and phase imbalance of the two diffraction orders of either incident beam. Solutions proposed previously only alleviate the former and have little help for the latter. In this paper, we introduce n=1 absorber to eliminate the phase imbalance so that the transverse shift between the two aerial images formed by the two incident beams can be minimized and the contrast of the final aerial image (by superposition of the two) can be restored.

  15. Object Substitution Masking: When Does Mask Preview Work?

    ERIC Educational Resources Information Center

    Lim, Stephen Wee Hun; Chua, Fook K.

    2008-01-01

    When a target is enclosed by a 4-dot mask that persists after the target disappears, target identification is worse than it is when the mask terminates with the target. This masking effect is attributed to object substitution masking (OSM). Previewing the mask, however, attenuates OSM. This study investigated specific conditions under which mask…

  16. Object Substitution Masking: When Does Mask Preview Work?

    ERIC Educational Resources Information Center

    Lim, Stephen Wee Hun; Chua, Fook K.

    2008-01-01

    When a target is enclosed by a 4-dot mask that persists after the target disappears, target identification is worse than it is when the mask terminates with the target. This masking effect is attributed to object substitution masking (OSM). Previewing the mask, however, attenuates OSM. This study investigated specific conditions under which mask…

  17. 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

  18. Sensorimotor supremacy: Investigating conscious and unconscious vision by masked priming

    PubMed Central

    Ansorge, Ulrich; Neumann, Odmar; Becker, Stefanie I.; Kälberer, Holger; Cruse, Holk

    2008-01-01

    According to the sensorimotor supremacy hypothesis, conscious perception draws on motor action. In the present report, we will sketch two lines of potential development in the field of masking research based on the sensorimotor supremacy hypothesis. In the first part of the report, evidence is reviewed that masked, invisible stimuli can affect motor responses, attention shifts, and semantic processes. After the review of the corresponding evidence – so-called masked priming effects – an approach based on the sensorimotor supremacy hypothesis is detailed as to how the question of a unitary mechanism of unconscious vision can be pursued by masked priming studies. In the second part of the report, different models and theories of backward masking and masked priming are reviewed. Types of models based on the sensorimotor hypothesis are discussed that can take into account ways in which sensorimotor processes (reflected in masked priming effects) can affect conscious vision under backward masking conditions. PMID:20517513

  19. Lightweight Face Mask

    NASA Technical Reports Server (NTRS)

    Cason, W. E. I.; Baucom, R. M.; Evans, R. C.

    1982-01-01

    Lightweight face mask originally developed to protect epileptic patients during seizures could have many other medical and nonmedical applications such as muscular distrophy patients, football linesmen and riot-control police. Masks are extremely lightweight, the lightest of the configurations weighing only 136 grams.

  20. Enhancement in Informational Masking

    ERIC Educational Resources Information Center

    Cao, Xiang; Richards, Virginia M.

    2012-01-01

    Purpose: The ability to detect a tone added to a random masker improves when a preview of the masker is provided. In 2 experiments, the authors explored the role that perceptual organization plays in this release from masking. Method: Detection thresholds were measured in informational masking studies. The maskers were drawn at random prior to…

  1. Lightweight Face Mask

    NASA Technical Reports Server (NTRS)

    Cason, W. E. I.; Baucom, R. M.; Evans, R. C.

    1982-01-01

    Lightweight face mask originally developed to protect epileptic patients during seizures could have many other medical and nonmedical applications such as muscular distrophy patients, football linesmen and riot-control police. Masks are extremely lightweight, the lightest of the configurations weighing only 136 grams.

  2. Enhancement in Informational Masking

    ERIC Educational Resources Information Center

    Cao, Xiang; Richards, Virginia M.

    2012-01-01

    Purpose: The ability to detect a tone added to a random masker improves when a preview of the masker is provided. In 2 experiments, the authors explored the role that perceptual organization plays in this release from masking. Method: Detection thresholds were measured in informational masking studies. The maskers were drawn at random prior to…

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

    SciTech Connect

    Kang, I.-Y.; Seo, H.-S.; Ahn, B.-S.; Lee, D.-G.; Kim, D.; Huh, S.; Koh, C.-W.; Cha, B.; Kim, S.-S.; Cho, H.-K.; Mochi, I.; Goldberg, K. A.

    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 defects 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.

  4. A practical alternating PSM modeling and OPC approach to deal with 3D mask effects for the 65nm node and beyond

    NASA Astrophysics Data System (ADS)

    Drapeau, Martin; van Adrichem, Paul J. M.; van Look, Lieve; Kasprowicz, Bryan S.

    2005-11-01

    Alternating PSM (Alt-PSM) has been recognized as a logical Resolution Enhancement Technique (RET) candidate for the 65nm technology node. One of the key properties this technique has to offer is high Depth of Focus (DOF) and lower Mask Error Enhancement Factor (MEEF). The so-called image imbalance is an Alt-PSM specific property which, if not dealt with correctly, constrains the added DOF. Because of mask topography, intensity differences caused by light scattering become evident between π (180°) and zero degree phase shifters. This causes a line shift that is inversely proportional to the pitch. The traditional solution of applying a fixed trench bias increases the width if the π phase shifter to level out intensities and thus minimize image imbalance. This technique may no longer be sufficient at the 65nm technology node. With the requirement to print even smaller pitches together with a tighter Critical Dimension (CD) budget, intensity imbalance is a larger concern. It may be necessary to apply a pitch dependent or variable trench bias. In this paper, we present a practical OPC modeling approach that accounts for image imbalance. The 2D modeling approach uses boundary layers to represent the 3D effect of light scattering. We demonstrate that with the boundary layer model, it is possible to predict image imbalance caused by mask 3D effects. The model can then be used either to determine the nominal trench bias or can be integrated into the OPC engine to apply a variable trench bias. Results are compared to rigorous Electro Magnetic Field (EMF) simulations and experimental exposures using an ArF scanner, targeting pitches of 130nm and above.

  5. Image tone optimization in advanced mask making for DUV lithography

    NASA Astrophysics Data System (ADS)

    Kim, Jong-doo; Do, Mun-hoe; Jeong, Seong-ho; Kim, Jea-hee; Kim, Keeho

    2007-03-01

    Deep-UV (DUV) lithography has been developed to define minimum feature sizes of sub-100 nm dimensions of devices semiconductor. In response to this trend, DUV mask technology has been proposed as an effective technique for considering the reduction of mask making cost, especially, in low volume designs. However, the requirement of tight CD control of the mask features in advanced devices is resulted in increasing of mask cost. In this research, we discussed two different typed image tones comparison, positive and negative tone, in DUV lithography. The choice of final mask tone needs to be selected as function of pattern density and shape. The evaluation items to judge if the mask is good are the OPC model accuracy, resolution and mask throughput. Both mask process and manufacturing throughput are affected by image tone type of positive and negative. This paper will show the procedures and results of experiment.

  6. Lithographic performance evaluation of a contaminated EUV mask after cleaning

    SciTech Connect

    George, Simi; Naulleau, Patrick; Okoroanyanwu, Uzodinma; Dittmar, Kornelia; Holfeld, Christian; Wuest, Andrea

    2009-11-16

    The effect of surface contamination and subsequent mask surface cleaning on the lithographic performance of a EUV mask is investigated. SEMATECH's Berkeley micro-field exposure tool (MET) printed 40 nm and 50 nm line and space (L/S) patterns are evaluated to compare the performance of a contaminated and cleaned mask to an uncontaminated mask. Since the two EUV masks have distinct absorber architectures, optical imaging models and aerial image calculations were completed to determine any expected differences in performance. Measured and calculated Bossung curves, process windows, and exposure latitudes for the two sets of L/S patterns are compared to determine how the contamination and cleaning impacts the lithographic performance of EUV masks. The observed differences in mask performance are shown to be insignificant, indicating that the cleaning process did not appreciably affect mask performance.

  7. Masking by Gratings Predicted by an Image Sequence Discriminating Model: Testing Models for Perceptual Discrimination Using Repeatable Noise

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Null, Cynthia H. (Technical Monitor)

    1998-01-01

    Adding noise to stimuli to be discriminated allows estimation of observer classification functions based on the correlation between observer responses and relevant features of the noisy stimuli. Examples will be presented of stimulus features that are found in auditory tone detection and visual vernier acuity. using the standard signal detection model (Thurstone scaling), we derive formulas to estimate the proportion of the observers decision variable variance that is controlled by the added noise. one is based on the probability of agreement of the observer with him/herself on trials with the same noise sample. Another is based on the relative performance of the observer and the model. When these do not agree, the model can be rejected. A second derivation gives the probability of agreement of observer and model when the observer follows the model except for internal noise. Agreement significantly less than this amount allows rejection of the model.

  8. Masking by Gratings Predicted by an Image Sequence Discriminating Model: Testing Models for Perceptual Discrimination Using Repeatable Noise

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Null, Cynthia H. (Technical Monitor)

    1998-01-01

    Adding noise to stimuli to be discriminated allows estimation of observer classification functions based on the correlation between observer responses and relevant features of the noisy stimuli. Examples will be presented of stimulus features that are found in auditory tone detection and visual vernier acuity. using the standard signal detection model (Thurstone scaling), we derive formulas to estimate the proportion of the observers decision variable variance that is controlled by the added noise. one is based on the probability of agreement of the observer with him/herself on trials with the same noise sample. Another is based on the relative performance of the observer and the model. When these do not agree, the model can be rejected. A second derivation gives the probability of agreement of observer and model when the observer follows the model except for internal noise. Agreement significantly less than this amount allows rejection of the model.

  9. 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.

  10. Reparing the mask industry

    NASA Astrophysics Data System (ADS)

    Lercel, Michael; Hector, Scott

    2006-10-01

    In many semiconductor markets, the largest fraction of total lithography cost is photomask cost; therefore any improvements in that area can have a noticeable impact on net chip cost. A significant yield loss mechanism for advanced photomasks is through nonrepairable defects. Providing improved methods to repair defects allows for improvements in mask yield and, therefore, the cost to make a defect-free mask and eventually the cost to produce the integrated circuit. However, the connection between mask yield and integrated circuit price is not a first-order relationship because it bridges between the mask supplier and end-user. SEMATECH and other worldwide consortia have, in the past, bridged this gap by sponsoring programs to develop improved mask infrastructure tools. A significant investment has been made in mask repair tool technology, but the quantitative benefit and return on investment has not been summarized until now. This paper attempts to show the strong benefits to the photomask and semiconductor industries from improving mask repair.

  11. 2012 Mask Industry Survey

    NASA Astrophysics Data System (ADS)

    Malloy, Matt; Litt, Lloyd C.

    2012-11-01

    A survey supported by SEMATECH and administered by David Powell Consulting was sent to semiconductor industry leaders to gather information about the mask industry as an objective assessment of its overall condition. The survey was designed with the input of semiconductor company mask technologists and merchant mask suppliers. 2012 marks the 11th consecutive year for the mask industry survey. This year's survey and reporting structure are similar to those of the previous years with minor modifications based on feedback from past years and the need to collect additional data on key topics. Categories include general mask information, mask processing, data and write time, yield and yield loss, delivery times, and maintenance and returns. Within each category are multiple questions that result in a detailed profile of both the business and technical status of the mask industry. Results, initial observations, and key comparisons between the 2011 and 2012 survey responses are shown here, including multiple indications of a shift towards the manufacturing of higher end photomasks.

  12. Masked Photocathode for Photoinjector

    SciTech Connect

    Qiang, Ji

    2010-01-21

    In this research note, we propose a scheme to insert a photocathode inside a photoinjector for generating high brightness electron beam. Instead of mounting the photocathode onto the electrode, a masked electrode with small hole is used to shield the photocathode from the accelerating vacuum chamber. Using such a masked photocathode will make the replacement of photocathode material very simple by rotating the photocathode behind the mask into the hole. This will significantly increase the usage lifetime of a photocathode. Furthermore, this also helps reduce the dark current or secondary electron emission from the photocathode. The hole on the mask also provides a transverse cut-off to the Gaussian laser profile which can be beneficial from the beam dynamics point of view.

  13. Protective Face Mask

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Mask to protect the physically impaired from injuries to the face and head has been developed by Langley Research Center. It is made of composite materials, usually graphite or boron fibers woven into a matrix. Weighs less than three ounces.

  14. Comodulation masking release in bottlenose dolphins (Tursiops truncatus).

    PubMed

    Branstetter, Brian K; Finneran, James J

    2008-07-01

    The acoustic environment of the bottlenose dolphin often consists of noise where energy across frequency regions is coherently modulated in time (e.g., ambient noise from snapping shrimp). However, most masking studies with dolphins have employed random Gaussian noise for estimating patterns of masked thresholds. The current study demonstrates a pattern of masking where temporally fluctuating comodulated noise produces lower masked thresholds (up to a 17 dB difference) compared to Gaussian noise of the same spectral density level. Noise possessing wide bandwidths, low temporal modulation rates, and across-frequency temporal envelope coherency resulted in lower masked thresholds, a phenomenon known as comodulation masking release. The results are consistent with a model where dolphins compare temporal envelope information across auditory filters to aid in signal detection. Furthermore, results suggest conventional models of masking derived from experiments using random Gaussian noise may not generalize well to environmental noise that dolphins actually encounter.

  15. New mask technology challenges

    NASA Astrophysics Data System (ADS)

    Kimmel, Kurt R.

    2001-09-01

    Mask technology development has accelerated dramatically in recent years from the glacial pace of the last three decades to the rapid and sometimes simultaneous introductions of new wavelengths and mask-based resolution enhancement techniques. The nature of the semiconductor business has also become one driven by time-to-market as an overwhelming factor in capturing market share and profit. These are among the factors that have created enormous stress on the mask industry to produce masks with enhanced capabilities, such as phase-shifting attenuators, sub-resolution assist bars, and optical proximity correction (OPC) features, while maintaining or reducing cost and cycle time. The mask can no longer be considered a commodity item that is purchased form the lowest-cost supplier. Instead, it must now be promoted as an integral part of the technical and business case for a total lithographic solution. Improving partnership between designer, mask-maker, and wafer lithographer will be the harbinger of success in finding a profitable balance of capability, cost, and cycle time. Likewise for equipment infrastructure development, stronger partnership on the international level is necessary to control development cost and mitigate schedule and technical risks.

  16. Mask Industry Assessment: 2011

    NASA Astrophysics Data System (ADS)

    Chan, Y. David

    2011-11-01

    A survey supported by SEMATECH and administered by David Powell Consulting was sent to microelectronics industry leaders to gather information about the mask industry as an objective assessment of its overall condition. The survey was designed with the input of semiconductor company mask technologists and merchant mask suppliers. This year's assessment is the tenth in the current series of annual reports. With ongoing industry support, the report has been used as one of the baselines to gain perspective on the technical and business status of the mask and microelectronics industries. It continues to serve as a valuable reference to identify the strengths and opportunities of the mask industry. The results will be used to guide future investments pertaining to critical path issues. This year's survey was essentially the same as the 2005 through 2010 surveys. Questions are grouped into following categories: General Business Profile Information, Data Processing, Yields and Yield Loss Mechanisms, Delivery Times, Returns, and Services. Within each category are multiple questions that result in a detailed profile of both the business and technical status of the critical mask industry. This profile combined with the responses to past surveys represents a comprehensive view of changes in the industry.

  17. Mask Industry Assessment: 2010

    NASA Astrophysics Data System (ADS)

    Hughes, Greg; Chan, David Y.

    2010-09-01

    A survey created supported by SEMATECH and administered by David Powell Consulting was sent to microelectronics industry leaders to gather information about the mask industry as an objective assessment of its overall condition. The survey was designed with the input of semiconductor company mask technologists and merchant mask suppliers. This year's assessment is the ninth in the current series of annual reports. With ongoing industry support, the report can be used as a baseline to gain perspective on the technical and business status of the mask and microelectronics industries. It will continue to serve as a valuable reference to identify the strengths and opportunities of the mask industry. The results will be used to guide future investments pertaining to critical path issues. This year's survey was basically the same as the 2005 through 2009 surveys. Questions are grouped into categories: General Business Profile Information, Data Processing, Yields and Yield Loss Mechanisms, Delivery Times, Returns, and Services. Within each category are multiple questions that result in a detailed profile of both the business and technical status of the critical mask industry. This profile combined with the responses to past surveys represents a comprehensive view of changes in the industry.

  18. Masks: The Artist in Me

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2009-01-01

    Whether masks are made from cardboard, papier-mache, metal, wood, leather, fabric, clay or any combination of these materials, they bring out the artist in people. Young children like to wear masks when they play to pretend they were another person or animal. Masks let them fantasize and be creative. The author's students made masks representing…

  19. Masks: The Artist in Me

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2009-01-01

    Whether masks are made from cardboard, papier-mache, metal, wood, leather, fabric, clay or any combination of these materials, they bring out the artist in people. Young children like to wear masks when they play to pretend they were another person or animal. Masks let them fantasize and be creative. The author's students made masks representing…

  20. Mask cost of ownership for advanced lithography

    NASA Astrophysics Data System (ADS)

    Muzio, Edward G.; Seidel, Philip K.

    2000-07-01

    As technology advances, becoming more difficult and more expensive, the cost of ownership (CoO) metric becomes increasingly important in evaluating technical strategies. The International SEMATECH CoC analysis has steadily gained visibility over the past year, as it attempts to level the playing field between technology choices, and create a fair relative comparison. In order to predict mask cots for advanced lithography, mask process flows are modeled using bets-known processing strategies, equipment cost, and yields. Using a newly revised yield mode, and updated mask manufacture flows, representative mask flows can be built. These flows are then used to calculate mask costs for advanced lithography down to the 50 nm node. It is never the goal of this type of work to provide absolute cost estimates for business planning purposes. However, the combination of a quantifiable yield model with a clearly defined set of mask processing flows and a cost model based upon them serves as an excellent starting point for cost driver analysis and process flow discussion.

  1. Active Mask Segmentation of Fluorescence Microscope Images

    PubMed Central

    Srinivasa, Gowri; Fickus, Matthew C.; Guo, Yusong; Linstedt, Adam D.; Kovačević, Jelena

    2009-01-01

    We propose a new active mask algorithm for the segmentation of fluorescence microscope images of punctate patterns. It combines the (a) flexibility offered by active-contour methods, (b) speed offered by multiresolution methods, (c) smoothing offered by multiscale methods, and (d) statistical modeling offered by region-growing methods into a fast and accurate segmentation tool. The framework moves from the idea of the “contour” to that of “inside and outside”, or, masks, allowing for easy multidimensional segmentation. It adapts to the topology of the image through the use of multiple masks. The algorithm is almost invariant under initialization, allowing for random initialization, and uses a few easily tunable parameters. Experiments show that the active mask algorithm matches the ground truth well, and outperforms the algorithm widely used in fluorescence microscopy, seeded watershed, both qualitatively as well as quantitatively. PMID:19380268

  2. Overview of Mask Metrology

    NASA Astrophysics Data System (ADS)

    Rice, Bryan J.; Jindal, Vibhu; Lin, C. C.; Harris-Jones, Jenah; Kwon, Hyuk Joo; Ma, Hsing-Chien; Goldstein, Michael; Chan, Yau-Wai; Goodwin, Frank

    2011-11-01

    Extreme ultraviolet (EUV) lithography is the successor to optical lithography and will enable advanced patterning in semiconductor manufacturing processes down to the 8 nm half pitch technology node and beyond. However, before EUV can successfully be inserted into high volume manufacturing a few challenges must be overcome. Central among these remaining challenges is the requirement to produce "defect free" EUV masks. Mask blank defects have been one of the top challenges in the commercialization of extreme ultraviolet (EUV) lithography. To determine defect sources and devise mitigation solutions, detailed characterization of defects is critical. However, small defects pose challenges in metrology scale-up. SEMATECH has a comprehensive metrology strategy to address any defect larger than a 20 nm core size to obtain solutions for defect-free EUV mask blanks. SEMATECH's Mask Blank Development Center has been working since 2003 to develop the technology to support defect free EUV mask blanks. Since 2003, EUV mask blank defects have been reduced from 10000 of size greater than 100 nm to about a few tens at size 70 nm. Unfortunately, today's state of the art defect levels are still about 10 to 100 times higher than needed. Closing this gap requires progress in the various processes associated with glass substrate creation and multilayer deposition. That process development improvement in turn relies upon the availability of metrology equipment that can resolve and chemically characterize defects as small as 30 nm. The current defect reduction efforts at SEMATECH have intensively included a focus on inspection and characterization. The facility boasts nearly 100M of metrology hardware, including an FEI Titan TEM, Lasertec M1350 and M7360 tools, an actinic inspection tool, AFM, SPM, and scanning auger capabilities. The newly established Auger tool at SEMATECH can run a standard 6-inch mask blank and is already providing important information on sub-100 nm defects on EUV

  3. MSB for ILT masks

    NASA Astrophysics Data System (ADS)

    Gramss, Juergen; Weidenmueller, Ulf; Stoeckel, Arnd; Jaritz, Renate; Doering, Hans-Joachim; Boettcher, Monika

    2011-03-01

    Multi Shaped Beam (MSB) throughput simulation results have already been published in the past. An IC mask set of a 32nm node logic device was one of the applications that had been analyzed in more detail. In this paper we want to highlight results of shot count and write time evaluations done for Inverse Lithography Technology (ILT) masks targeting the 22nm technology node. The test pattern data we used for these practice-oriented analyses was designed by DNP / Japan and created by Luminescent Technologies, Inc. / USA. To achieve reliable evaluation results, the influence of different MSB configurations on shot count and mask write time has been taken into account and will be discussed here. Exposure results of pattern details are presented and compared with the fracturing result. The MSB engineering tool we used for our investigations covers such major components like an electron-optical column, a precision x/y stage and the MSB data path.

  4. 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

  5. Evaluation of a next generation EB mask writer for hp 32nm lithography

    NASA Astrophysics Data System (ADS)

    Komagata, Tadashi; Hasegawa, Takahisa; Goto, Kazuya; Kono, Kenji; Yamamoto, Ryuuji; Nishida, Naoki; Nakagawa, Yasutoshi

    2010-05-01

    Lithography technologies promising for the half pitch (HP) 32 nm generation include 193 nm immersion with water, extreme ultraviolet lithography (EUVL), and nano-imprint lithography (NIL). Among these, 193 nm immersion with water is considered a mainstream for hp 32 nm device fabrication in terms of performance and device production costs. Meanwhile, according to the International Technology Roadmap for Semiconductors (ITRS) 2009, the optical masks for hp 32 nm devices need to meet extremely strict requirements; for example, an image placement accuracy of 3.8 nm (2.7 nm for double patterning), and CD uniformities of 1.5 nm (isolated lines) and 2.4 nm (dense lines). To meet these accuracy requirements, we have developed JBX-3200MV, a variable shaped beam mask writer featuring an accelerating voltage of 50 kV and a current density of 70 A/cm2. For this new writer, we developed a new digital-to-analog converter (DAC) amplifier designed to reduce noises input to electron beam optics components such as the main and sub positioning deflectors and the beam shaping deflectors. The stage and exposure chambers were enhanced in rigidity to reduce mechanical noises. The position of the stage is measured by laser devices with a finer resolution of 0.15 nm, and the measured results are fed back to the beam position. In addition, data transfer speed and proximity correction speed were improved to handle larger data volumes. Our exposure test results demonstrate that the new lithography system, installed at the leading-edge mask production facility, achieved the hp 32 nm mask accuracies required by the ITRS 2009.

  6. Microscale rarefied gas dynamics and surface interactions for EUVL and MEMS applications.

    SciTech Connect

    Gallis, Michail A.; Rader, Daniel John; Castaneda, Jaime N.; Torczynski, John Robert; Grasser, Thomas W.; Trott, Wayne Merle

    2004-11-01

    A combined experimental/modeling study was conducted to better understand the critical role of gas-surface interactions in rarefied gas flows. An experimental chamber and supporting diagnostics were designed and assembled to allow simultaneous measurements of gas heat flux and inter-plate gas density profiles in an axisymmetric, parallel-plate geometry. Measurements of gas density profiles and heat flux are made under identical conditions, eliminating an important limitation of earlier studies. The use of in situ, electron-beam fluorescence is demonstrated as a means to measure gas density profiles although additional work is required to improve the accuracy of this technique. Heat flux is inferred from temperature-drop measurements using precision thermistors. The system can be operated with a variety of gases (monatomic, diatomic, polyatomic, mixtures) and carefully controlled, well-characterized surfaces of different types (metals, ceramics) and conditions (smooth, rough). The measurements reported here are for 304 stainless steel plates with a standard machined surface coupled with argon, helium, and nitrogen. The resulting heat-flux and gas-density-profile data are analyzed using analytic and computational models to show that a simple Maxwell gas-surface interaction model is adequate to represent all of the observations. Based on this analysis, thermal accommodation coefficients for 304 stainless steel coupled with argon, nitrogen, and helium are determined to be 0.88, 0.80, and 0.38, respectively, with an estimated uncertainty of {+-}0.02.

  7. Incomplete figure perception and invisible masking.

    PubMed

    Chikhman, Valery; Shelepin, Yuri; Foreman, Nigel; Merkuljev, Aleksey; Pronin, Sergey

    2006-01-01

    The Gollin test (measuring recognition thresholds for fragmented line drawings of everyday objects and animals) has traditionally been regarded as a test of incomplete figure perception or 'closure', though there is a debate about how such closure is achieved. Here, figural incompleteness is considered to be the result of masking, such that absence of contour elements of a fragmented figure is the result of the influence of an 'invisible' mask. It is as though the figure is partly obscured by a mask having parameters identical to those of the background. This mask is 'invisible' only consciously, but for the early stages of visual processing it is real and has properties of multiplicative noise. Incomplete Gollin figures were modeled as the figure covered by the mask with randomly distributed transparent and opaque patches. We adjusted the statistical characteristics of the contour image and empty noise patches and processed those using spatial and spatial-frequency measures. Across 73 figures, despite inter-subject variability, mean recognition threshold was always approximately 15% of total contour in naive observers. Recognition worsened with increasing spectral similarity between the figure and the 'invisible' mask. Near threshold, the spectrum of the fragmented image was equally similar to that of the 'invisible' mask and complete image. The correlation between spectral parameters of figures at threshold and complete figures was greatest for figures that were most easily recognised. Across test sessions, thresholds reduced when either figure or mask parameters were familiar. We argue that recognition thresholds for Gollin stimuli in part reflect the extraction of signal from noise.

  8. Robust source and mask optimization compensating for mask topography effects in computational lithography.

    PubMed

    Li, Jia; Lam, Edmund Y

    2014-04-21

    Mask topography effects need to be taken into consideration for a more accurate solution of source mask optimization (SMO) in advanced optical lithography. However, rigorous 3D mask models generally involve intensive computation and conventional SMO fails to manipulate the mask-induced undesired phase errors that degrade the usable depth of focus (uDOF) and process yield. In this work, an optimization approach incorporating pupil wavefront aberrations into SMO procedure is developed as an alternative to maximize the uDOF. We first design the pupil wavefront function by adding primary and secondary spherical aberrations through the coefficients of the Zernike polynomials, and then apply the conjugate gradient method to achieve an optimal source-mask pair under the condition of aberrated pupil. We also use a statistical model to determine the Zernike coefficients for the phase control and adjustment. Rigorous simulations of thick masks show that this approach provides compensation for mask topography effects by improving the pattern fidelity and increasing uDOF.

  9. Lithographic characterization of improved projection optics in the EUVL engineering test stand

    NASA Astrophysics Data System (ADS)

    O'Connell, Donna J.; Lee, Sang Hun; Ballard, William P.; Tichenor, Daniel A.; Bernardez, Louis J., II; Haney, Steven J.; Johnson, Terry A.; Barr, Pamela K.; Leung, Alvin H.; Jefferson, Karen L.; Replogle, William C.; Goldsmith, John E. M.; Chapman, Henry N.; Naulleau, Patrick P.; Wurm, Stefan; Panning, Eric M.

    2003-06-01

    Static and scanned images of 100nm dense features for a developmental set of l/14 optics (projection optics box # 1, POB 1) in the Engineering Test Stand (ETS) were successfully obtained with various LPP source powers last year. The ETS with POB1 has been used to understand initial system performance and lithographic learning. Since then, numerous system upgrades have been made to improve ETS lithographic performance to meet or exceed the original design objectives. The most important upgrade is the replacement of POB 1 with an improved projection optics system, POB2, having lower figure error (l/20 rms wavefront error) and lower flare. Both projection optics boxes are a four-mirror design with a 0.1 numerical aperture. Scanned 70-nm dense features have been successfully printed using POB2. Aerial image contrast measurements have been made using the resist clearing method. The results are in good agreement to previous POB2 aerial image contrast measurements at the subfield exposure station (SES) at Lawrence Berkeley National Laboratory. For small features the results deviate from the modeling predictions due to the inherent resolution limit of the resist. The intrinsic flare of POB2 was also characterized. The experimental results were in excellent agreement with modeling predictions. As predicted, the flare in POB2 is less than 20% for 2μm features, which is two times lower than the flare in POB1. EUV flare is much easier to compensate for than its DUV counterpart due to its greater degree of uniformity and predictability. The lithographic learning obtained from the ETS will be used in the development of EUV High Volume Manufacturing tools. This paper describes the ETS tool ETS tool setup, both static and scanned, that was required after the installation of POB2. The paper will also describe the lithographic characterization of POB2 in the ETS and cmpare those results to the lithographic results obtained last year with POB1.

  10. COAs: Behind the Masks.

    ERIC Educational Resources Information Center

    Birke, Szifra

    1993-01-01

    Provides information on alcoholism and codependency to help teachers identify and respond to children of alcoholics (COAs). Discusses characteristics of alcoholic homes and problems encountered by children and adult COAs. Examines survival "masks" of COAs, including hero, rebel, adjustor, clown, and caretaker. Lists organizational,…

  11. COAs: Behind the Masks.

    ERIC Educational Resources Information Center

    Birke, Szifra

    1993-01-01

    Provides information on alcoholism and codependency to help teachers identify and respond to children of alcoholics (COAs). Discusses characteristics of alcoholic homes and problems encountered by children and adult COAs. Examines survival "masks" of COAs, including hero, rebel, adjustor, clown, and caretaker. Lists organizational,…

  12. The laryngeal mask airway.

    PubMed

    Brimacombe, J; Shorney, N

    The laryngeal mask airway is a new development in airway management. It became commercially available in 1988 and has since become an integral part of anaesthetic practice; its potential outside anaesthesia is rapidly developing. This article describes the basic concepts, methods of insertion and applications, current and projected.

  13. Masked mycotoxins: A review

    PubMed Central

    Berthiller, Franz; Crews, Colin; Dall'Asta, Chiara; Saeger, Sarah De; Haesaert, Geert; Karlovsky, Petr; Oswald, Isabelle P; Seefelder, Walburga; Speijers, Gerrit; Stroka, Joerg

    2013-01-01

    The aim of this review is to give a comprehensive overview of the current knowledge on plant metabolites of mycotoxins, also called masked mycotoxins. Mycotoxins are secondary fungal metabolites, toxic to human and animals. Toxigenic fungi often grow on edible plants, thus contaminating food and feed. Plants, as living organisms, can alter the chemical structure of mycotoxins as part of their defence against xenobiotics. The extractable conjugated or non-extractable bound mycotoxins formed remain present in the plant tissue but are currently neither routinely screened for in food nor regulated by legislation, thus they may be considered masked. Fusarium mycotoxins (deoxynivalenol, zearalenone, fumonisins, nivalenol, fusarenon-X, T-2 toxin, HT-2 toxin, fusaric acid) are prone to metabolisation or binding by plants, but transformation of other mycotoxins by plants (ochratoxin A, patulin, destruxins) has also been described. Toxicological data are scarce, but several studies highlight the potential threat to consumer safety from these substances. In particular, the possible hydrolysis of masked mycotoxins back to their toxic parents during mammalian digestion raises concerns. Dedicated chapters of this article address plant metabolism as well as the occurrence of masked mycotoxins in food, analytical aspects for their determination, toxicology and their impact on stakeholders. PMID:23047235

  14. Apodized Phase Mask Coronagraphs

    NASA Astrophysics Data System (ADS)

    Carlotti, Alexis

    2013-01-01

    Among the optical instruments proposed to detect and characterize exoplanets, phase masks coronagraphs offer very small inner working angles. Designed for off-axis telescopes, their performance is greatly reduced when used with centrally obstructed apertures such as those of the Palomar telescope, the very large telescope, or the James Webb space telescope. However, a clear circular aperture is not the only pupil shape for which a phase mask coronagraph can work properly. In fact, for a given centrally obstructed aperture, we show that it is possible to compute optimal apodizers that help achieve stellar extinction levels similar to those obtained in the ideal case of an off-axis telescope. Trade-offs exist between these levels, the transmission of the apodizer, and the area covered by the Lyot stop. We detail the Fourier optics formalism that makes these optimizations possible, as well as a few examples of shaped pupils. Some are designed for a four-quadrants phase mask, and some others for a vortex phase mask. We also offer a comparison with a coronagraph solely composed of a shaped pupil.

  15. Masked mycotoxins: a review.

    PubMed

    Berthiller, Franz; Crews, Colin; Dall'Asta, Chiara; Saeger, Sarah De; Haesaert, Geert; Karlovsky, Petr; Oswald, Isabelle P; Seefelder, Walburga; Speijers, Gerrit; Stroka, Joerg

    2013-01-01

    The aim of this review is to give a comprehensive overview of the current knowledge on plant metabolites of mycotoxins, also called masked mycotoxins. Mycotoxins are secondary fungal metabolites, toxic to human and animals. Toxigenic fungi often grow on edible plants, thus contaminating food and feed. Plants, as living organisms, can alter the chemical structure of mycotoxins as part of their defence against xenobiotics. The extractable conjugated or non-extractable bound mycotoxins formed remain present in the plant tissue but are currently neither routinely screened for in food nor regulated by legislation, thus they may be considered masked. Fusarium mycotoxins (deoxynivalenol, zearalenone, fumonisins, nivalenol, fusarenon-X, T-2 toxin, HT-2 toxin, fusaric acid) are prone to metabolisation or binding by plants, but transformation of other mycotoxins by plants (ochratoxin A, patulin, destruxins) has also been described. Toxicological data are scarce, but several studies highlight the potential threat to consumer safety from these substances. In particular, the possible hydrolysis of masked mycotoxins back to their toxic parents during mammalian digestion raises concerns. Dedicated chapters of this article address plant metabolism as well as the occurrence of masked mycotoxins in food, analytical aspects for their determination, toxicology and their impact on stakeholders.

  16. Competing for Consciousness: Prolonged Mask Exposure Reduces Object Substitution Masking

    ERIC Educational Resources Information Center

    Goodhew, Stephanie C.; Visser, Troy A. W.; Lipp, Ottmar V.; Dux, Paul E.

    2011-01-01

    In object substitution masking (OSM) a sparse, temporally trailing 4-dot mask impairs target identification, even though it has different contours from, and does not spatially overlap with the target. Here, we demonstrate a previously unknown characteristic of OSM: Observers show reduced masking at prolonged (e.g., 640 ms) relative to intermediate…

  17. Effect of mask dead space and occlusion of mask holes on delivery of nebulized albuterol.

    PubMed

    Berlinski, Ariel

    2014-08-01

    Infants and children with respiratory conditions are often prescribed bronchodilators. Face masks are used to facilitate the administration of nebulized therapy in patients unable to use a mouthpiece. Masks incorporate holes into their design, and their occlusion during aerosol delivery has been a common practice. Masks are available in different sizes and different dead volumes. The aim of this study was to compare the effect of different degrees of occlusion of the mask holes and different mask dead space on the amount of nebulized albuterol available at the mouth opening in a model of a spontaneously breathing child. A breathing simulator mimicking infant (tidal volume [VT] = 50 mL, breathing frequency = 30 breaths/min, inspiratory-expiratory ratio [I:E] = 1:3), child (VT = 155 mL, breathing frequency = 25 breaths/min, I:E = 1:2), and adult (VT = 500 mL, breathing frequency = 15 breaths/min, I:E = 1:2) breathing patterns was connected to a collection filter hidden behind a face plate. A pediatric size mask and an adult size mask connected to a continuous output jet nebulizer were sealed to the face plate. Three nebulizers were loaded with albuterol sulfate (2.5 mg/3 mL) and operated with 6 L/min compressed air for 5 min. Experiments were repeated with different degrees of occlusion (0%, 50%, and 90%). Albuterol was extracted from the filter and measured with a spectrophotometer at 276 nm. Occlusion of the holes in the large mask did not increase the amount of albuterol in any of the breathing patterns. The amount of albuterol captured at the mouth opening did not change when the small mask was switched to the large mask, except with the breathing pattern of a child, and when the holes in the mask were 50% occluded (P = .02). Neither decreasing the dead space of the mask nor occluding the mask holes increased the amount of nebulized albuterol captured at the mouth opening.

  18. Mask costs: a new look

    NASA Astrophysics Data System (ADS)

    Grenon, Brian J.; Hector, Scott

    2006-06-01

    Over the last decade SEMATECH has provided significant guidance in predicting mask costs and their potential effects on the cost of manufacturing semiconductors. Additionally, these projections have been used to appropriately fund activities that could have the most impact on reducing mask costs, improving quality and cycle time. The most recent cost projections provide a comprehensive look at the impact of improvements to the mask fabrication process. We will provide projections that clearly indicate that appropriately funded mask technologies can have a significant impact on manufacturing yields and hence, cost and cycle time. While historical mask cost projections were realistic, the new projections represent the best estimates for mask costs over the next several years based on the current mask technology and processes1. These projections are significantly more optimistic than previous estimates. These changes are due primarily to the introduction of new mask repair technologies, improvements in focused ion beam (FIB), nano-machining and femto-second laser repair.

  19. Compensation of overlay errors due to mask bending and non-flatness for EUV masks

    NASA Astrophysics Data System (ADS)

    Chandhok, Manish; Goyal, Sanjay; Carson, Steven; Park, Seh-Jin; Zhang, Guojing; Myers, Alan M.; Leeson, Michael L.; Kamna, Marilyn; Martinez, Fabian C.; Stivers, Alan R.; Lorusso, Gian F.; Hermans, Jan; Hendrickx, Eric; Govindjee, Sanjay; Brandstetter, Gerd; Laursen, Tod

    2009-03-01

    EUV blank non-flatness results in both out of plane distortion (OPD) and in-plane distortion (IPD) [3-5]. Even for extremely flat masks (~50 nm peak to valley (PV)), the overlay error is estimated to be greater than the allocation in the overlay budget. In addition, due to multilayer and other thin film induced stresses, EUV masks have severe bow (~1 um PV). Since there is no electrostatic chuck to flatten the mask during the e-beam write step, EUV masks are written in a bent state that can result in ~15 nm of overlay error. In this article we present the use of physically-based models of mask bending and non-flatness induced overlay errors, to compensate for pattern placement of EUV masks during the e-beam write step in a process we refer to as E-beam Writer based Overlay error Correction (EWOC). This work could result in less restrictive tolerances for the mask blank non-flatness specs which in turn would result in less blank defects.

  20. Respiratory source control using surgical masks with nanofiber media.

    PubMed

    Skaria, Shaji D; Smaldone, Gerald C

    2014-07-01

    Potentially infected individuals ('source') are sometimes encouraged to use face masks to reduce exposure of their infectious aerosols to others ('receiver'). To improve compliance with Respiratory Source Control via face mask and therefore reduce receiver exposure, a mask should be comfortable and effective. We tested a novel face mask designed to improve breathability and filtration using nanofiber filtration. Using radiolabeled test aerosols and a calibrated exposure chamber simulating source to receiver interaction, facepiece function was measured with a life-like ventilated manikin model. Measurements included mask airflow resistance (pressure difference during breathing), filtration, (mask capture of exhaled radiolabeled test aerosols), and exposure (the transfer of 'infectious' aerosols from the 'source' to a 'receiver'). Polydisperse aerosols were measured at the source with a mass median aerodynamic diameter of 0.95 µm. Approximately 90% of the particles were <2.0 µm. Tested facepieces included nanofiber prototype surgical masks, conventional surgical masks, and for comparison, an N95-class filtering facepiece respirator (commonly known as an 'N95 respirator'). Airflow through and around conventional surgical face mask and nanofiber prototype face mask was visualized using Schlieren optical imaging. Airflow resistance [ΔP, cmH2O] across sealed surgical masks (means: 0.1865 and 0.1791 cmH2O) approached that of the N95 (mean: 0.2664 cmH2O). The airflow resistance across the nanofiber face mask whether sealed or not sealed (0.0504 and 0.0311 cmH2O) was significantly reduced in comparison. In addition, 'infected' source airflow filtration and receiver exposure levels for nanofiber face masks placed on the source were comparable to that achieved with N95 placed on the source; 98.98% versus 82.68% and 0.0194 versus 0.0557, respectively. Compared to deflection within and around the conventional face masks, Schlieren optical imaging demonstrated enhanced

  1. Respiratory Source Control Using Surgical Masks With Nanofiber Media

    PubMed Central

    Skaria, Shaji D.; Smaldone, Gerald C.

    2014-01-01

    Background: Potentially infected individuals (‘source’) are sometimes encouraged to use face masks to reduce exposure of their infectious aerosols to others (‘receiver’). To improve compliance with Respiratory Source Control via face mask and therefore reduce receiver exposure, a mask should be comfortable and effective. We tested a novel face mask designed to improve breathability and filtration using nanofiber filtration. Methods: Using radiolabeled test aerosols and a calibrated exposure chamber simulating source to receiver interaction, facepiece function was measured with a life-like ventilated manikin model. Measurements included mask airflow resistance (pressure difference during breathing), filtration, (mask capture of exhaled radiolabeled test aerosols), and exposure (the transfer of ‘infectious’ aerosols from the ‘source’ to a ‘receiver’). Polydisperse aerosols were measured at the source with a mass median aerodynamic diameter of 0.95 µm. Approximately 90% of the particles were <2.0 µm. Tested facepieces included nanofiber prototype surgical masks, conventional surgical masks, and for comparison, an N95-class filtering facepiece respirator (commonly known as an ‘N95 respirator’). Airflow through and around conventional surgical face mask and nanofiber prototype face mask was visualized using Schlieren optical imaging. Results: Airflow resistance [ΔP, cmH2O] across sealed surgical masks (means: 0.1865 and 0.1791 cmH2O) approached that of the N95 (mean: 0.2664 cmH2O). The airflow resistance across the nanofiber face mask whether sealed or not sealed (0.0504 and 0.0311 cmH2O) was significantly reduced in comparison. In addition, ‘infected’ source airflow filtration and receiver exposure levels for nanofiber face masks placed on the source were comparable to that achieved with N95 placed on the source; 98.98% versus 82.68% and 0.0194 versus 0.0557, respectively. Compared to deflection within and around the conventional face

  2. Mask Blank Defect Detection

    SciTech Connect

    Johnson, M A; Sommargren, G E

    2000-02-04

    Mask blanks are the substrates that hold the master patterns for integrated circuits. Integrated circuits are semiconductor devices, such as microprocessors (mPs), dynamic random access memory (DRAMs), and application specific integrated circuits (ASICs) that are central to the computer, communication, and electronics industries. These devices are fabricated using a set of master patterns that are sequentially imaged onto light-sensitive coated silicon wafers and processed to form thin layers of insulating and conductive materials on top of the wafer. These materials form electrical paths and transistors that control the flow of electricity through the device. For the past forty years the semiconductor industry has made phenomenal improvements in device functionality, compactness, speed, power, and cost. This progress is principally due to the exponential decrease in the minimum feature size of integrated circuits, which has been reduced by a factor of {radical}2 every three years. Since 1992 the Semiconductor Industry Association (SIA) has coordinated the efforts of producing a technology roadmap for semiconductors. In the latest document, ''The International Technology Roadmap for Semiconductors: 1999'', future technology nodes (minimum feature sizes) and targeted dates were specified and are summarized in Table 1. Lithography is the imaging technology for producing a de-magnified image of the mask on the wafer. A typical de-magnification factor is 4. Mask blank defects as small as one-eighth the equivalent minimum feature size are printable and may cause device failure. Defects might be the result of the surface preparation, such as polishing, or contamination due to handling or the environment. Table 2 shows the maximum tolerable defect sizes on the mask blank for each technology node. This downward trend puts a tremendous burden on mask fabrication, particularly in the area of defect detection and reduction. A new infrastructure for mask inspection will be

  3. Advances in mask fabrication and alignment for masked ion-beam lithography

    NASA Astrophysics Data System (ADS)

    Stumbo, David P.; Damm, George A.; Engler, D. W.; Fong, F. O.; Sen, S.; Wolfe, John C.; Randall, John N.; Mauger, Phillip E.; Shimkunas, Alex R.; Loeschne, Hans

    1990-05-01

    This paper describes recent developments in three areas ofmasked ion beam lithography (MIBL). These are 1) fabrication oflarge area, low distortion, silicon stencilmasks for demagnifying ion projection lithography, 2) fabrication ofstencil masks with nanometer scale resolution for 1:1 proximity printing, and 3) development of a direct method of alignment using the ion beam induced fluorescence of Si02. These topics are discussed below. Demagnifying ion projection masks: We describe the fabrication of stencil masks in large area, low stress (10 MPa), n-type silicon membranes. The projection masks have a silicon foil area 95 mm in diameter, thicknesses between 1.5-5 and resolution of0.6um. Measured distortion (3a) in the IPL masks ranges between 0.23gm and 0.65,um, with an experimental error of 0.20 1um. Proximity printing masks: A process is described for fabricating stencil masks with 50 nm resolution in low stress, n-type silicon membranes. Membranes less than 0.5 ,ttm thick are shown to be free of the sidewall taper that limits resolution in thicker masks. These thin membranes show a slightly flared profile due to the imperfectly collimated etching ions. Alignment: A direct method of alignment is being developed which uses the ion beam induced fluorescence of Si02 marks. Fluorescence yield is characterized as a function of ion energy and resist coating thickness. The yield for Si02 is in the range between 0.1-1.0 photons/proton, while the yields for Si, Al, and photoresist are negligibly small. Thus, a simple alignment technique can be implemented where registration of a grating in the mask with a corresponding oxide pattern is detected as a fluorescence maximum. A simple model predicts that 50 nm alignment can be accomplished, following a 1 im prealignment, in 2 seconds.

  4. Comparison of manually triggered ventilation and bag-valve-mask ventilation during cardiopulmonary resuscitation in a manikin model.

    PubMed

    Bergrath, Sebastian; Rossaint, Rolf; Biermann, Henning; Skorning, Max; Beckers, Stefan K; Rörtgen, Daniel; Brokmann, Jörg Ch; Flege, Christian; Fitzner, Christina; Czaplik, Michael

    2012-04-01

    To compare a novel, pressure-limited, flow adaptive ventilator that enables manual triggering of ventilations (MEDUMAT Easy CPR, Weinmann, Germany) with a bag-valve-mask (BVM) device during simulated cardiac arrest. Overall 74 third-year medical students received brief video instructions (BVM: 57s, ventilator: 126s), standardised theoretical instructions and practical training for both devices. Four days later, the students were randomised into 37 two-rescuer teams and were asked to perform 8min of cardiopulmonary resuscitation (CPR) on a manikin using either the ventilator or the BVM (randomisation list). Applied tidal volumes (V(T)), inspiratory times and hands-off times were recorded. Maximum airway pressures (P(max)) were measured with a sensor connected to the artificial lung. Questionnaires concerning levels of fatigue, stress and handling were evaluated. V(T), pressures and hands-off times were compared using t-tests, questionnaire data were analysed using the Wilcoxon test. BVM vs. ventilator (mean±SD): the mean V(T) (408±164ml vs. 315±165ml, p=0.10) and the maximum V(T) did not differ, but the number of recorded V(T)<200ml differed (8.1±11.3 vs. 17.0±14.4 ventilations, p=0.04). P(max) did not differ, but inspiratory times (0.80±0.23s vs. 1.39±0.31s, p<0.001) and total hands-off times (133.5±17.8s vs. 162.0±11.1s, p<0.001) did. The estimated levels of fatigue and stress were comparable; however, the BVM was rated to be easier to use (p=0.03). For the user group investigated here, this ventilator exhibits no advantages in the setting of simulated CPR and carries a risk of prolonged no-flow time. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  5. Evaluation of mask manufacturing efficiency using mask data rank information

    NASA Astrophysics Data System (ADS)

    Kato, Kokoro; Endo, Masakazu; Inoue, Tadao; Yamabe, Masaki; Nakatake, Shigetoshi

    2010-05-01

    The photomask cost is becoming one of the challenging issues in the semiconductor industry, as the cost of photomasks has been rising year by year. ASET started Mask D2I (Mask Design, Drawing and Inspection Technology) project with the sponsorship from the NEDO (New Energy and Industrial Technology Development Organization) in 2006 for the purpose of the mask cost reduction. In earlier papers[1-5], we introduced the idea of photomask data prioritization method which is referred to as Mask Data Rank (MDR). We have built our software system to convert Design Intent (DI) to MDR with cooperation of STARC. Then we showed the results of experiments with mask data provided by semiconductor companies. In this paper we show the additional report of mask inspection experiments using real photomasks. Then we show the evaluation results about mask drawing time reduction using MDR flow. Finally we introduce detailed algorithm to extract design intent from analog circuits.

  6. Printability and actinic AIMS review of programmed mask blank defects

    NASA Astrophysics Data System (ADS)

    Verduijn, Erik; Mangat, Pawitter; Wood, Obert; Rankin, Jed; Chen, Yulu; Goodwin, Francis; Capelli, Renzo; Perlitz, Sascha; Hellweg, Dirk; Bonam, Ravi; Matham, Shravan; Felix, Nelson; Corliss, Daniel

    2017-03-01

    We report on the printability, mitigation and actinic mask level review of programmed substrate blank pit and bump defects in a EUV lithography test mask. We show the wafer printing behavior of these defects exposed with an NXE:3300 EUV lithography scanner and the corresponding mask level actinic review using the AIMSTM tool. We will show which categories of these blank substrate defects print on wafer and how they can be mitigated by hiding these defects under absorber lines. Furthermore we show that actinic AIMSTM mask review images of these defects, in combination with a simple thresholded resist transfer model, can accurately predict their wafer printing profiles. We also compare mask level actinic AIMSTM to top down mask SEM review in their ability to detect these defects.

  7. Quality enhancement of parallel MDP flows with mask suppliers

    NASA Astrophysics Data System (ADS)

    Deng, Erwin; Lee, Rachel; Lee, Chun Der

    2013-06-01

    For many maskshops, designed parallel mask data preparation (MDP) flows accompanying with a final data comparison are viewed as a reliable method that could reduce quality risks caused by mis-operation. However, in recent years, more and more mask data mistakes have shown that present parallel MDP flows could not capture all mask data errors yet. In this paper, we will show major failure models of parallel MDP flows from analyzing MDP quality accidents and share our approaches to achieve further improvement with mask suppliers together.

  8. Mask industry quality assessment

    NASA Astrophysics Data System (ADS)

    Strott, Al; Bassist, Larry

    1994-12-01

    Product quality and timely delivery are two of the most important parameters in determining the success of a mask manufacturing facility. Because of the sensitivity of this data, very little was known about industry performance in these areas until an assessment was authored and presented at the 1993 BACUS Symposium by Larry Regis of Intel Corporation, Neil Paulsen of Intel Corporation, and James A. Reynolds of Reynolds Consulting. This data has been updated and will be published and presented at this year's BACUS Symposium. Contributor identities will again remain protected by utilizing Arthur Andersen & Company to compile the submittals. Participation was consistent with last year's representation of over 75% of the total merchant and captive mask volume in the United States. The data compiled includes shipments, customer return rate, customer return reasons from 1988 through Q2, 1994, performance to schedule, plate survival yield, and throughput time (TPT).

  9. RHIC Prefire Protection Masks

    SciTech Connect

    Drees, A.; Biscardi, C.; Curcio, T.; Gassner, D.; DeMonte, V.; DeSanto, L.; Fu, W.; Liaw, C. J.; Montag, C.; Thieberger, P.; Yip, K.

    2015-01-07

    The protection of the RHIC experimental detectors from damage due to beam hitting close upstream elements in cases of abort kicker prefires requires some dedicated precautionary measures with two general options: to bring the beam close to a limiting aperture (i.e. the beam pipe wall), as far upstream of the detector components as possible or, alternatively, to bring a limiting aperture close to the circulating beam. During the FY 2014 RHIC Heavy Ion run the first option was chosen because of the limited time available for preparation before the start of the run. For future runs the second option, in this case the installation of dual-sided movable masks, is preferred. The installation of the masks, one per ring, is planned before the start of the FY 2015 run.

  10. Masks: Culture and Kids.

    ERIC Educational Resources Information Center

    Patterson, MaryEllen; And Others

    This guide describes a 7-day lesson plan to be used with bilingual 3rd and 4th graders and 6th, 7th, and 8th graders in English-as-a-Second-Language (ESL) classes. The guide shows how mask making can be tied into each class, and then how to pull the classes together for the older students to become peer tutors to the younger ones in the…

  11. Masked multichannel analyzer

    DOEpatents

    Winiecki, Alan L.; Kroop, David C.; McGee, Marilyn K.; Lenkszus, Frank R.

    1986-01-01

    An analytical instrument and particularly a time-of-flight-mass spectrometer for processing a large number of analog signals irregularly spaced over a spectrum, with programmable masking of portions of the spectrum where signals are unlikely in order to reduce memory requirements and/or with a signal capturing assembly having a plurality of signal capturing devices fewer in number than the analog signals for use in repeated cycles within the data processing time period.

  12. Masked multichannel analyzer

    DOEpatents

    Winiecki, A.L.; Kroop, D.C.; McGee, M.K.; Lenkszus, F.R.

    1984-01-01

    An analytical instrument and particularly a time-of-flight-mass spectrometer for processing a large number of analog signals irregularly spaced over a spectrum, with programmable masking of portions of the spectrum where signals are unlikely in order to reduce memory requirements and/or with a signal capturing assembly having a plurality of signal capturing devices fewer in number than the analog signals for use in repeated cycles within the data processing time period.

  13. On Masking Effect

    DTIC Science & Technology

    1993-07-01

    solution will perform better than the others and present experimental data supportive of the analysis. This investigation is based on simulated robot...solution will perform better than the agent’s task is to catch the evasion agent. Both agents others, and present experimental data supportive of the...Masking interception, and the resultant time lost from hiding and The previous section ruled out refinement stratgies replanning. Without the learned rule

  14. The Attentional Dynamics of Masked Detection

    ERIC Educational Resources Information Center

    Smith, Philip L.; Wolfgang, Bradley J.

    2004-01-01

    A dichoptic masking procedure was used to test whether the mask-dependent cuing effects found in luminance detection by P. L. Smith (2000a) were due to integration masking or interruption masking. Attentional cuing enhanced detection sensitivity (d') when stimuli were backwardly masked with either dichoptic or monoptic masks, whereas no cuing…

  15. EUV mask black border evolution

    NASA Astrophysics Data System (ADS)

    Turley, Christina; Bonam, Ravi; Gallagher, Emily; Grohs, Jonathan; Kagawa, Masayuki; Kindt, Louis; Narita, Eisuke; Nash, Steven; Sakamoto, Yoshifumi

    2014-10-01

    The black border is a frame created by removing all the multilayers on the EUV mask in the region around the chip. It is created to prevent exposure of adjacent fields when printing an EUV mask on a wafer. Papers have documented its effectiveness. As the technology transitions into manufacturing, the black border must be optimized from the initial mask making process through its life. In this work, the black border is evaluated in three stages: the black border during fabrication, the final sidewall profile, and extended lifetime studies. This work evaluates the black border through simulations and physical experiments. The simulations address concerns for defects and sidewall profiles. The physical experiments test the current black border process. Three masks are used: one mask to test how black border affects the image placement of features on mask and two masks to test how the multilayers change through extended cleans. Data incorporated in this study includes: registration, reflectivity, multilayer structure images and simulated wafer effects. By evaluating the black border from both a mask making perspective and a lifetime perspective, we are able to characterize how the structure evolves. The mask data and simulations together predict the performance of the black border and its ability to maintain critical dimensions on wafer. In this paper we explore what mask changes occur and how they will affect mask use.

  16. Mask strategy at International SEMATECH

    NASA Astrophysics Data System (ADS)

    Kimmel, Kurt R.

    2002-08-01

    International SEMATECH (ISMT) is a consortium consisting of 13 leading semiconductor manufacturers from around the globe. Its objective is to develop the infrastructure necessary for its member companies to realize the International Technology Roadmap for Semiconductors (ITRS) through efficiencies of shared development resources and knowledge. The largest area of effort is lithography, recognized as a crucial enabler for microelectronics technology progress. Within the Lithography Division, most of the efforts center on mask-related issues. The development strategy at International SEMATCH will be presented and the interlock of lithography projects clarified. Because of the limited size of the mask production equipment market, the business case is weak for aggressive investment commensurate with the pace of the International Technology Roadmap for Semiconductors. With masks becoming the overwhelming component of lithography cost, new ways of reducing or eliminating mask costs are being explored. Will mask technology survive without a strong business case? Will the mask industry limit the growth of the semiconductor industry? Are advanced masks worth their escalating cost? An analysis of mask cost from the perspective of mask value imparted to the user is presented with examples and generic formulas for the reader to apply independently. A key part to the success for both International SEMATECH and the industry globally will be partnerships on both the local level between mask-maker and mask-user, and the macro level where global collaborations will be necessary to resolve technology development cost challenges.

  17. Masks in imaging flow cytometry.

    PubMed

    Dominical, Venina; Samsel, Leigh; McCoy, J Philip

    2017-01-01

    Data analysis in imaging flow cytometry incorporates elements of flow cytometry together with other aspects of morphological analysis of images. A crucial early step in this analysis is the creation of a mask to distinguish the portion of the image upon which further examination of specified features can be performed. Default masks are provided by the manufacturer of the imaging flow cytometer but additional custom masks can be created by the individual user for specific applications. Flawed or inaccurate masks can have a substantial negative impact on the overall analysis of a sample, thus great care must be taken to ensure the accuracy of masks. Here we discuss various types of masks and cite examples of their use. Furthermore we provide our insight for how to approach selecting and assessing the optimal mask for a specific analysis.

  18. Cost of mask fabrication

    NASA Astrophysics Data System (ADS)

    Trybula, Walter J.; Dance, Daren L.

    1997-07-01

    The development of the cost of ownership methodology provided the semiconductor industry with a process that is employed to evaluate the life cycle costs of any particular equipment. Applying this technique has provided a cost focus on areas of potential improvement. The existing methodology is equipment centric. The limitation of this process is that there has not been a means of evaluating the impact of the cost of ownership for a process. An evaluation of process requirements indicated that such a tool would provide an advantage for evaluating not only the process flow cost but also allocate the individual cost of ownership values according to the planned volumes and yields. This would not be the comprehensive evaluation that can be done with dynamic simulation, but a static first approximation at total process costs based on a combined process flow. This paper describes the application of this new process to the development of the process cost of ownership to the optical mask production process. The program employed in work, PRO COOLTM, was developed by WWK in conjunction with SEMATECH. This paper describes the application of process cost of ownership to the optical mask production process sequence. Using a generic mask fabrication flow, process sequence cost of ownership analysis is used to identify cost drivers, throughput limitations, and process cost sensitivities. This generic process flow consists of the data evaluation and general number crunching requirements at the beginning of the process, followed by exposure, develop, inspection, measure, CD, pelliclize, inspect, and ship. Understanding of the relationship of these factors will help evaluate future mask fabrication technologies and requirements. Analyzing a generic optical mask production process sequence showed that the simple approach of adding process step cost of ownership values underestimates the process cost of ownership. Thus a complete analysis must consider the cost of unused capacity in

  19. Masking exposes multiple global form mechanisms

    PubMed Central

    Webb, Ben S.; Roach, Neil W.; Peirce, Jon W.

    2011-01-01

    Previous work suggests there are mechanisms at intermediate levels of visual processing specialized for the detection of radial and circular form. The evidence in favor of specialized global form mechanisms is derived from structure detection experiments that have told us very little about their bandwidth or number. To address these related questions, we examined the effects of configural backward masking on human observers’ ability to detect global structure in arrays with different spiral forms. Each array consisted of 100 Gabors randomly positioned within a circular annular window. Observers judged which of two sequentially presented Gabor arrays contained global structure. One array contained Gabors with random orientations; the other contained Gabors with a variable proportion of orientations coherent with a randomly chosen spiral pitch. At its offset, each array was immediately followed by a backward masking Gabor array with a fixed spiral pitch angle. When mask and test had the same spiral pitch, we found an approximately three-fold elevation of structure detection thresholds that was not explained by local orientation masking. The magnitude and breadth of tuning around each masking angle was predicted by a simple model consisting of at least eight detectors broadly tuned for different spiral forms. PMID:18831652

  20. Metabolic power of European starlings Sturnus vulgaris during flight in a wind tunnel, estimated from heat transfer modelling, doubly labelled water and mask respirometry.

    PubMed

    Ward, S; Möller, U; Rayner, J M V; Jackson, D M; Nachtigall, W; Speakman, J R

    2004-11-01

    It is technically demanding to measure the energetic cost of animal flight. Each of the previously available techniques has some disadvantage as well advantages. We compared measurements of the energetic cost of flight in a wind tunnel by four European starlings Sturnus vulgaris made using three independent techniques: heat transfer modelling, doubly labelled water (DLW) and mask respirometry. We based our heat transfer model on thermal images of the surface temperature of the birds and air flow past the body and wings calculated from wing beat kinematics. Metabolic power was not sensitive to uncertainty in the value of efficiency when estimated from heat transfer modelling. A change in the assumed value of whole animal efficiency from 0.19 to 0.07 (the range of estimates in previous studies) only altered metabolic power predicted from heat transfer modelling by 13%. The same change in the assumed value of efficiency would cause a 2.7-fold change in metabolic power if it were predicted from mechanical power. Metabolic power did not differ significantly between measurements made using the three techniques when we assumed an efficiency in the range 0.11-0.19, although the DLW results appeared to form a U-shaped power-speed curve while the heat transfer model and respirometry results increased linearly with speed. This is the first time that techniques for determining metabolic power have been compared using data from the same birds flying under the same conditions. Our data provide reassurance that all the techniques produce similar results and suggest that heat transfer modelling may be a useful method for estimating metabolic rate.

  1. Mask Design for the Space Interferometry Mission Internal Metrology

    NASA Technical Reports Server (NTRS)

    Marx, David; Zhao, Feng; Korechoff, Robert

    2005-01-01

    This slide presentation reviews the mask design used for the internal metrology of the Space Interferometry Mission (SIM). Included is information about the project, the method of measurements with SIM, the internal metrology, numerical model of internal metrology, wavefront examples, performance metrics, and mask design

  2. Pattern transfer with stabilized nanoparticle etch masks.

    PubMed

    Hogg, Charles R; Picard, Yoosuf N; Narasimhan, Amrit; Bain, James A; Majetich, Sara A

    2013-03-01

    Self-assembled nanoparticle monolayer arrays are used as an etch mask for pattern transfer into Si and SiO(x) substrates. Crack formation within the array is prevented by electron beam curing to fix the nanoparticles to the substrate, followed by a brief oxygen plasma to remove excess carbon. This leaves a dot array of nanoparticle cores with a minimum gap of 2 nm. Deposition and liftoff can transform the dot array mask into an antidot mask, where the gap is determined by the nanoparticle core diameter. Reactive ion etching is used to transfer the dot and antidot patterns into the substrate. The effect of the gap size on the etching rate is modeled and compared with the experimental results.

  3. Pattern transfer with stabilized nanoparticle etch masks

    NASA Astrophysics Data System (ADS)

    Hogg, Charles R.; Picard, Yoosuf N.; Narasimhan, Amrit; Bain, James A.; Majetich, Sara A.

    2013-03-01

    Self-assembled nanoparticle monolayer arrays are used as an etch mask for pattern transfer into Si and SiOx substrates. Crack formation within the array is prevented by electron beam curing to fix the nanoparticles to the substrate, followed by a brief oxygen plasma to remove excess carbon. This leaves a dot array of nanoparticle cores with a minimum gap of 2 nm. Deposition and liftoff can transform the dot array mask into an antidot mask, where the gap is determined by the nanoparticle core diameter. Reactive ion etching is used to transfer the dot and antidot patterns into the substrate. The effect of the gap size on the etching rate is modeled and compared with the experimental results.

  4. Overlay improvement by exposure map based mask registration optimization

    NASA Astrophysics Data System (ADS)

    Shi, Irene; Guo, Eric; Chen, Ming; Lu, Max; Li, Gordon; Li, Rivan; Tian, Eric

    2015-03-01

    Along with the increased miniaturization of semiconductor electronic devices, the design rules of advanced semiconductor devices shrink dramatically. [1] One of the main challenges of lithography step is the layer-to-layer overlay control. Furthermore, DPT (Double Patterning Technology) has been adapted for the advanced technology node like 28nm and 14nm, corresponding overlay budget becomes even tighter. [2][3] After the in-die mask registration (pattern placement) measurement is introduced, with the model analysis of a KLA SOV (sources of variation) tool, it's observed that registration difference between masks is a significant error source of wafer layer-to-layer overlay at 28nm process. [4][5] Mask registration optimization would highly improve wafer overlay performance accordingly. It was reported that a laser based registration control (RegC) process could be applied after the pattern generation or after pellicle mounting and allowed fine tuning of the mask registration. [6] In this paper we propose a novel method of mask registration correction, which can be applied before mask writing based on mask exposure map, considering the factors of mask chip layout, writing sequence, and pattern density distribution. Our experiment data show if pattern density on the mask keeps at a low level, in-die mask registration residue error in 3sigma could be always under 5nm whatever blank type and related writer POSCOR (position correction) file was applied; it proves random error induced by material or equipment would occupy relatively fixed error budget as an error source of mask registration. On the real production, comparing the mask registration difference through critical production layers, it could be revealed that registration residue error of line space layers with higher pattern density is always much larger than the one of contact hole layers with lower pattern density. Additionally, the mask registration difference between layers with similar pattern density

  5. Mask alignment system for semiconductor processing

    DOEpatents

    Webb, Aaron P.; Carlson, Charles T.; Weaver, William T.; Grant, Christopher N.

    2017-02-14

    A mask alignment system for providing precise and repeatable alignment between ion implantation masks and workpieces. The system includes a mask frame having a plurality of ion implantation masks loosely connected thereto. The mask frame is provided with a plurality of frame alignment cavities, and each mask is provided with a plurality of mask alignment cavities. The system further includes a platen for holding workpieces. The platen may be provided with a plurality of mask alignment pins and frame alignment pins configured to engage the mask alignment cavities and frame alignment cavities, respectively. The mask frame can be lowered onto the platen, with the frame alignment cavities moving into registration with the frame alignment pins to provide rough alignment between the masks and workpieces. The mask alignment cavities are then moved into registration with the mask alignment pins, thereby shifting each individual mask into precise alignment with a respective workpiece.

  6. Assessing EUV mask defectivity

    NASA Astrophysics Data System (ADS)

    Okoroanyanwu, Uzodinma; Tchikoulaeva, Anna; Ackmann, Paul; Wood, Obert; La Fontaine, Bruno; Bubke, Karsten; Holfeld, Christian; Peters, Jan Hendrik; Kini, Sumanth; Watson, Sterling; Lee, Isaac; Mu, Bo; Lim, Phillip; Raghunathan, Sudhar; Boye, Carol

    2010-04-01

    This paper assesses the readiness of EUV masks for pilot line production. The printability of well characterized reticle defects, with particular emphasis on those reticle defects that cause electrical errors on wafer test chips, is investigated. The reticles are equipped with test marks that are inspected in a die-to-die mode (using DUV inspection tool) and reviewed (using a SEM tool), and which also comprise electrically testable patterns. The reticles have three modules comprising features with 32 nm ground rules in 104 nm pitch, 22 nm ground rules with 80 nm pitch, and 16 nm ground rules with 56 nm pitch (on the wafer scale). In order to determine whether specific defects originate from the substrate, the multilayer film, the absorber stack, or from the patterning process, the reticles were inspected after each fabrication step. Following fabrication, the reticles were used to print wafers on a 0.25 NA full-field ASML EUV exposure tool. The printed wafers were inspected with state of the art bright-field and Deep UV inspection tools. It is observed that the printability of EUV mask defects down to a pitch of 56 nm shows a trend of increased printability as the pitch of the printed pattern gets smaller - a well established trend at larger pitches of 80 nm and 104 nm, respectively. The sensitivity of state-of-the-art reticle inspection tools is greatly improved over that of the previous generation of tools. There appears to be no apparent decline in the sensitivity of these state-of-the-art reticle inspection tools for higher density (smaller) patterns on the mask, even down to 56nm pitch (1x). Preliminary results indicate that a blank defect density of the order of 0.25 defects/cm2 can support very early learning on EUV pilot line production at the 16nm node.

  7. Accelerating volcanic ash data assimilation using a mask-state algorithm based on an ensemble Kalman filter: a case study with the LOTOS-EUROS model (version 1.10)

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Lin, Hai Xiang; Heemink, Arnold; Lu, Sha; Segers, Arjo; van Velzen, Nils; Lu, Tongchao; Xu, Shiming

    2017-04-01

    In this study, we investigate a strategy to accelerate the data assimilation (DA) algorithm. Based on evaluations of the computational time, the analysis step of the assimilation turns out to be the most expensive part. After a study of the characteristics of the ensemble ash state, we propose a mask-state algorithm which records the sparsity information of the full ensemble state matrix and transforms the full matrix into a relatively small one. This will reduce the computational cost in the analysis step. Experimental results show the mask-state algorithm significantly speeds up the analysis step. Subsequently, the total amount of computing time for volcanic ash DA is reduced to an acceptable level. The mask-state algorithm is generic and thus can be embedded in any ensemble-based DA framework. Moreover, ensemble-based DA with the mask-state algorithm is promising and flexible, because it implements exactly the standard DA without any approximation and it realizes the satisfying performance without any change in the full model.

  8. Masks of the Universe

    NASA Astrophysics Data System (ADS)

    Harrison, Edward

    2003-05-01

    Preface; Introducing the masks; Part I. Worlds in the Making: 1. The magic Universe; 2. The mythic Universe; 3. The geometric Universe; 4. The medieval Universe; 5. The infinite Universe; 6. The mechanistic Universe; Part II. The Heart Divine: 7. Dance of the atoms and waves; 8. Fabric of space and time; 9. Nearer to the heart's desire; 10. The cosmic tide; 11. Do dreams ever come true?; Part III. The Cloud of Unknowing: 12. The witch universe; 13. The spear of Archytas; 14. All that is made; 15. The cloud of unknowing; 16. Learned ignorance.

  9. Mask fabrication process

    DOEpatents

    Cardinale, Gregory F.

    2000-01-01

    A method for fabricating masks and reticles useful for projection lithography systems. An absorber layer is conventionally patterned using a pattern and etch process. Following the step of patterning, the entire surface of the remaining top patterning photoresist layer as well as that portion of an underlying protective photoresist layer where absorber material has been etched away is exposed to UV radiation. The UV-exposed regions of the protective photoresist layer and the top patterning photoresist layer are then removed by solution development, thereby eliminating the need for an oxygen plasma etch and strip and chances for damaging the surface of the substrate or coatings.

  10. Trends in mask data preparation

    NASA Astrophysics Data System (ADS)

    Fujimura, Aki; Pang, Liyong; Su, Bo; Choi, Yohan

    2014-10-01

    Whether for VSB mask writing or for multibeam mask writing, the shapes we need to write on masks are increasingly complex, increasingly curvilinear, and smaller in minimum width and space. The overwhelming trend in mask data preparation (MDP) is the shift from deterministic, rule-based, geometric, context-independent, shape-modulated, rectangular processing to statistical, simulation-based, context-dependent, dose- and shape-modulated any-shape processing. The paper briefly surveys the history of MDP, and explains through a simulation-based study that 50nm line and space is the tipping point where rule-based processing gives away to simulation-based processing.

  11. Masked hypertension: a systematic review.

    PubMed

    Bobrie, Guillaume; Clerson, Pierre; Ménard, Joël; Postel-Vinay, Nicolas; Chatellier, Gilles; Plouin, Pierre-François

    2008-09-01

    The purpose of this research was to review the literature on masked hypertension. Studies, reviews and editorials on masked hypertension were identified by PubMed, Pascal BioMed and Cochrane literature systematic searches. Then, we carried out a meta-analysis of the six cohort studies reporting quantitative data for masked hypertension prognosis. There is still no clear consensus definition of masked hypertension and the reproducibility of the phenomenon is unknown. Nevertheless, the prevalence of masked hypertension seems to lie between 8 and 20%, and can be up to 50% in treated hypertensive patients. Subjects with masked hypertension have a higher risk of cardiovascular accidents [hazard ratios: 1.92 (1.51-2.44)] than normotensive subjects. This is due to a possible failure to recognize and appropriately manage this particular form of hypertension, the frequent association with other risk factors and coexisting target organ damage. The remaining unresolved questions are as follows: is masked hypertension a clinical entity that requires identification and characterization or a statistical phenomenon linked to the variability of blood pressure measurements?; because screening of the entire population is not feasible, how to identify individuals with masked hypertension?; and, in the absence of randomized trial, how to treat masked hypertension?

  12. A Masked Photocathode in Photoinjector

    SciTech Connect

    Qiang, Ji

    2010-12-14

    In this paper, we propose a masked photocathode inside the photoinjector for generating high brightness election beam. Instead of mounting the photocathode onto an electrode, an electrode with small hole is used as a mask to shield the photocathode from the accelerating vacuum chamber. Using such a masked photocathode will make the replacement of photocathode material easy by rotating the photocathode behind the electrode into the hole. Furthermore, this helps reduce the dark current or secondary electron emission from the photocathode material. The masked photocathode also provides transverse cut-off to a Gaussian laser beam that reduces electron beam emittance growth from nonlinear space-charge effects.

  13. Akathisia masked by hypokinesia.

    PubMed

    Tuisku, K; Lauerma, H; Holi, M M; Honkonen, T; Rimon, R

    2000-07-01

    Here, we will discuss the concept of subjective akathisia and present a patient case. Our patient was suffering from neuroleptic-induced hypokinesia and akathisia at the same time. The typical motor manifestations of akathisia were masked by hypokinesia, which made the diagnosis difficult. However, the subjective symptoms of akathisia were evident and distressing. Although not observable to bare eye, the pathognomonic pattern of motor activity detected in akathisia was demonstrated by actometric recording. Changing the conventional neuroleptic to an atypical one brought relief to the subjective symptoms of akathisia and hypokinesia, while the motor activity was clearly diminished in actometric recording. Actometric recording may be useful in diagnosing akathisia masked by hypokinesia, but the typical subjective symptoms of akathisia should not be ignored, even when actometry is not available to demonstrate the missing motor component of akathisia. Not only akathisia defined by DSM-IV but also subjective akathisia should be adequately treated to relieve the subjective distress, and to diminish the unfavorable effects on psychotic symptoms, behavior, and drug compliance.

  14. EFFECT OF MASKED REGIONS ON WEAK-LENSING STATISTICS

    SciTech Connect

    Shirasaki, Masato; Yoshida, Naoki; Hamana, Takashi

    2013-09-10

    Sky masking is unavoidable in wide-field weak-lensing observations. We study how masks affect the measurement of statistics of matter distribution probed by weak gravitational lensing. We first use 1000 cosmological ray-tracing simulations to examine in detail the impact of masked regions on the weak-lensing Minkowski Functionals (MFs). We consider actual sky masks used for a Subaru Suprime-Cam imaging survey. The masks increase the variance of the convergence field and the expected values of the MFs are biased. The bias then compromises the non-Gaussian signals induced by the gravitational growth of structure. We then explore how masks affect cosmological parameter estimation. We calculate the cumulative signal-to-noise ratio (S/N) for masked maps to study the information content of lensing MFs. We show that the degradation of S/N for masked maps is mainly determined by the effective survey area. We also perform simple {chi}{sup 2} analysis to show the impact of lensing MF bias due to masked regions. Finally, we compare ray-tracing simulations with data from a Subaru 2 deg{sup 2} survey in order to address if the observed lensing MFs are consistent with those of the standard cosmology. The resulting {chi}{sup 2}/n{sub dof} = 29.6/30 for three combined MFs, obtained with the mask effects taken into account, suggests that the observational data are indeed consistent with the standard {Lambda}CDM model. We conclude that the lensing MFs are a powerful probe of cosmology only if mask effects are correctly taken into account.

  15. What Is Being Masked in Object Substitution Masking?

    ERIC Educational Resources Information Center

    Gellatly, Angus; Pilling, Michael; Cole, Geoff; Skarratt, Paul

    2006-01-01

    Object substitution masking (OSM) is said to occur when a perceptual object is hypothesized that is mismatched by subsequent sensory evidence, leading to a new hypothesized object being substituted for the first. For example, when a brief target is accompanied by a longer lasting display of nonoverlapping mask elements, reporting of target…

  16. Removal of particles from lithographic masks through plasma-assisted cleaning by metastable atomic neutralization

    NASA Astrophysics Data System (ADS)

    Lytle, W. M.; Szybilski, D. S.; Das, C. E.; Raju, R.; Surla, V.; Neumann, M. J.; Ruzic, D. N.

    2008-11-01

    For extreme ultraviolet lithography (EUVL) to become a high volume manufacturing technology for integrated circuit manufacturing, the cleanliness of the system, especially the photomask, is of high importance. For EUV photomasks, which cannot be protected from contamination by the use of a pellicle, an effective and quick cleaning technology needs to be ready in order to maintain wafer throughput. There are challenges to extend current wet cleaning technologies to meet the future needs for damage-free and high efficiency mask cleaning. Accordingly, a unique process for cleaning particulates from surfaces, specifically photomasks as well as wafers, has been evaluated at the University of Illinois Urbana-Champaign. The removal technique utilizes a high density plasma source as well as pulsed substrate biases to provide for removal. Helium is used as the primary gas in the plasma, which under ionization, provides for a large density of helium metastable atoms present in the plasma. These metastable helium atoms have on the order of 20 eV of energy which can transfer to particles on the substrate to be cleaned. When the substrate is under a small flux of ion bombardment, these bonds then remain broken and it is theorized that this allows the particles to be volatilized for their subsequent removal. 100 % particle removal efficiency has been obtained for 30 nm, 80 nm, and 200 nm polystyrene latex particles. In addition, removal rate has been correlated with helium metastable population density determined by optical emission spectroscopy.

  17. Simplified tooling for spray masking

    NASA Technical Reports Server (NTRS)

    Dinbar, B. J.; Hammons, R. E.

    1978-01-01

    Tooling technique involves positioning tiles within acrylic plastic masking frames that attach magnetically to holding fixture. Plastics are "magnetized" with adhesive mangetic-rubber strips. Technique is simpler and less expensive than conventional methods. L-shaped masks are easily cut and altered.

  18. Masked Repetition Priming Using Magnetoencephalography

    ERIC Educational Resources Information Center

    Monahan, Philip J.; Fiorentino, Robert; Poeppel, David

    2008-01-01

    Masked priming is used in psycholinguistic studies to assess questions about lexical access and representation. We present two masked priming experiments using MEG. If the MEG signal elicited by words reflects specific aspects of lexical retrieval, then one expects to identify specific neural correlates of retrieval that are sensitive to priming.…

  19. Masked Repetition Priming Using Magnetoencephalography

    ERIC Educational Resources Information Center

    Monahan, Philip J.; Fiorentino, Robert; Poeppel, David

    2008-01-01

    Masked priming is used in psycholinguistic studies to assess questions about lexical access and representation. We present two masked priming experiments using MEG. If the MEG signal elicited by words reflects specific aspects of lexical retrieval, then one expects to identify specific neural correlates of retrieval that are sensitive to priming.…

  20. 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.

  1. Taste masking microspheres for orally disintegrating tablets.

    PubMed

    Xu, Jianchen; Bovet, Li Li; Zhao, Kang

    2008-07-09

    The purpose of this study was to evaluate the potential of microspheres for taste masking when incorporated into orally disintegrating tablets. The microspheres were produced by spray drying a mixture of the model compound (famotidine) with taste masking material. The spray process was optimized using a central composite design for two variables to obtain microspheres with desirable characteristics. Then the microspheres were mixed with other excipients to form orally disintegrating tablets. The optimal spray-drying process parameters were 34mg/ml for solid concentration and 7ml/min for feed rate. The drug encapsulation efficiency of the spray-dried microspheres ranges from of 37.59 to 61.56%, with a mean diameter of less than 10microm size and low moisture content (less than 4%). Results from an evaluation by a panel of six human volunteers demonstrated that the orally disintegrating tablets with taste masking microspheres improved the taste significantly. Furthermore, an in vivo study in rats showed that the microspheres neither decrease the bioavailability nor retard the release of famotidine significantly. In conclusion, spray-dried microspheres can effectively mask the bitter taste of the active pharmaceutical ingredients in combination with the orally disintegrating tablets.

  2. Masked object registration in the Fourier domain.

    PubMed

    Padfield, Dirk

    2012-05-01

    Registration is one of the most common tasks of image analysis and computer vision applications. The requirements of most registration algorithms include large capture range and fast computation so that the algorithms are robust to different scenarios and can be computed in a reasonable amount of time. For these purposes, registration in the Fourier domain using normalized cross-correlation is well suited and has been extensively studied in the literature. Another common requirement is masking, which is necessary for applications where certain regions of the image that would adversely affect the registration result should be ignored. To address these requirements, we have derived a mathematical model that describes an exact form for embedding the masking step fully into the Fourier domain so that all steps of translation registration can be computed efficiently using Fast Fourier Transforms. We provide algorithms and implementation details that demonstrate the correctness of our derivations. We also demonstrate how this masked FFT registration approach can be applied to improve the Fourier-Mellin algorithm that calculates translation, rotation, and scale in the Fourier domain. We demonstrate the computational efficiency, advantages, and correctness of our algorithm on a number of images from real-world applications. Our framework enables fast, global, parameter-free registration of images with masked regions.

  3. Optimization of mask shot count using MB-MDP and lithography simulation

    NASA Astrophysics Data System (ADS)

    Chua, Gek Soon; Wang, Wei Long; Choi, Byoung IL; Zou, Yi; Tabery, Cyrus; Bork, Ingo; Nguyen, Tam; Fujimura, Aki

    2011-11-01

    In order to maintain manageable process windows, mask shapes at the 20nm technology node and below become so complex that mask write times reach 40 hours or might not be writeable at all since the extrapolated write time reaches 80 hours. The recently introduced Model Based Mask Data Preparation (MB-MDP) technique is able to reduce shot count and therefore mask write time by using overlapping shots. Depending on the amount of shot count reduction the contour of the mask shapes is changed leading to the question how the mask contour influences wafer performance. This paper investigates the tradeoff between mask shot count reduction using MB-MDP and wafer performance using lithography simulation. A typical Source-Mask-Optimization (SMO) result for a 20nm technology will be used as an example.

  4. A prototype erodible mask delivery system for the excimer laser.

    PubMed

    Maloney, R K; Friedman, M; Harmon, T; Hayward, M; Hagen, K; Gailitis, R P; Waring, G O

    1993-04-01

    The authors developed an erodible mask delivery system for the argon-fluoride 193-nm excimer laser, which offers the possibility of correcting hyperopia and astigmatism as well as myopia. Masks were made of polymethylmethacrylate on a quartz window, with intended corrections for myopia and hyperopia of 2.5 and 5 diopters (D). Ablations using the mask and control ablations using an expanding diaphragm were performed in 30 eyes of 15 pigmented rabbits with an Excimed UV200 laser (Summit Technology, Inc, Waltham, MA). The rabbits were followed for 134 days with regular biomicroscopy and retinoscopic examination by two observers. Ablations with the mask to correct myopia were successful and produced stable corrections, although the higher-power mask produced undercorrections. Hyperopic masks produced paradoxic myopic corrections, possibly due to the lack of a transition zone at the edge of the mask. Corneas ablated with the mask had less sub-epithelial haze than those ablated with the diaphragm at all examinations. Results of histopathologic examination showed epithelial hyperplasia over the ablation zone in all eyes. Dichlorotriazinyl aminofluorescein collagen staining showed subepithelial new collagen in all eyes, but there was no relation between the depth of ablation at any point on the cornea and the amount of new collagen deposited there. Myopic ablations are feasible with the erodible mask, although additional calibration is needed. Hyperopic ablations were unsuccessful with the current design. Corneas ablated with the mask may be clearer than corneas ablated with the diaphragm, possibly due to a smoother ablated surface. Regression of effect after laser ablation in the rabbit model is likely due more to epithelial hyperplasia than to stromal remodeling.

  5. Bringing mask repair to the next level

    NASA Astrophysics Data System (ADS)

    Edinger, K.; Wolff, K.; Steigerwald, H.; Auth, N.; Spies, P.; Oster, J.; Schneider, H.; Budach, M.; Hofmann, T.; Waiblinger, M.

    2014-10-01

    Mask repair is an essential step in the mask manufacturing process as the extension of 193nm technology and the insertion of EUV are drivers for mask complexity and cost. The ability to repair all types of defects on all mask blank materials is crucial for the economic success of a mask shop operation. In the future mask repair is facing several challenges. The mask minimum features sizes are shrinking and require a higher resolution repair tool. At the same time mask blanks with different new mask materials are introduced to optimize optical performance and long term durability. For EUV masks new classes of defects like multilayer and phase defects are entering the stage. In order to achieve a high yield, mask repair has to cover etch and deposition capabilities and must not damage the mask. These challenges require sophisticated technologies to bring mask repair to the next level. For high end masks ion-beam based and e-based repair technologies are the obvious choice when it comes to the repair of small features. Both technologies have their pro and cons. The scope of this paper is to review and compare the performance of ion-beam based mask repair to e-beam based mask repair. We will analyze the limits of both technologies theoretically and experimentally and show mask repair related performance data. Based on this data, we will give an outlook to future mask repair tools.

  6. Sensitivity of coded mask telescopes.

    PubMed

    Skinner, Gerald K

    2008-05-20

    Simple formulas are often used to estimate the sensitivity of coded mask x-ray or gamma-ray telescopes, but these are strictly applicable only if a number of basic assumptions are met. Complications arise, for example, if a grid structure is used to support the mask elements, if the detector spatial resolution is not good enough to completely resolve all the detail in the shadow of the mask, or if any of a number of other simplifying conditions are not fulfilled. We derive more general expressions for the Poisson-noise-limited sensitivity of astronomical telescopes using the coded mask technique, noting explicitly in what circumstances they are applicable. The emphasis is on using nomenclature and techniques that result in simple and revealing results. Where no convenient expression is available a procedure is given that allows the calculation of the sensitivity. We consider certain aspects of the optimization of the design of a coded mask telescope and show that when the detector spatial resolution and the mask to detector separation are fixed, the best source location accuracy is obtained when the mask elements are equal in size to the detector pixels.

  7. Sensitivity of coded mask telescopes

    SciTech Connect

    Skinner, Gerald K

    2008-05-20

    Simple formulas are often used to estimate the sensitivity of coded mask x-ray or gamma-ray telescopes, but these are strictly applicable only if a number of basic assumptions are met. Complications arise, for example, if a grid structure is used to support the mask elements, if the detector spatial resolution is not good enough to completely resolve all the detail in the shadow of the mask, or if any of a number of other simplifying conditions are not fulfilled. We derive more general expressions for the Poisson-noise-limited sensitivity of astronomical telescopes using the coded mask technique, noting explicitly in what circumstances they are applicable. The emphasis is on using nomenclature and techniques that result in simple and revealing results. Where no convenient expression is available a procedure is given that allows the calculation of the sensitivity. We consider certain aspects of the optimization of the design of a coded mask telescope and show that when the detector spatial resolution and the mask to detector separation are fixed, the best source location accuracy is obtained when the mask elements are equal in size to the detector pixels.

  8. Biological Activity of Masked Endotoxin

    PubMed Central

    Schwarz, Harald; Gornicec, Jan; Neuper, Theresa; Parigiani, Maria Alejandra; Wallner, Michael; Duschl, Albert; Horejs-Hoeck, Jutta

    2017-01-01

    Low endotoxin recovery (LER) is a recently discovered phenomenon describing the inability of limulus amebocyte lysate (LAL)-based assays to detect lipopolysaccharide (LPS) because of a “masking effect” caused by chelators or detergents commonly used in buffer formulations for medical products and recombinant proteins. This study investigates the masking capacities of different buffer formulations and whether masked endotoxin is biologically active. We show that both naturally occurring endotoxin as well as control standard endotoxin can be affected by LER. Furthermore, whereas masked endotoxin cannot be detected in Factor C based assays, it is still detectable in a cell-based TLR4-NF-κB-luciferase reporter gene assay. Moreover, in primary human monocytes, masked LPS induces the expression of pro-inflammatory cytokines and surface activation markers even at very low concentrations. We therefore conclude that masked LPS is a potent trigger of immune responses, which emphasizes the potential danger of masked LPS, as it may pose a health threat in pharmaceutical products or compromise experimental results. PMID:28317862

  9. Infrared Signature Masking by Air Plasma Radiation

    NASA Technical Reports Server (NTRS)

    Kruger, C. H.; Laux, C. O.

    1998-01-01

    This report describes progress during the second year of our research program on Infrared Signature Masking by Air Plasmas at Stanford University. This program is intended to investigate the masking of infrared signatures by the air plasma formed behind the bow shock of high velocity missiles. Our previous annual report described spectral measurements and modeling of the radiation emitted between 3.2 and 5.5 microns by an atmospheric pressure air plasma in chemical and thermal equilibrium at a temperature of approximately 3100 K. One of our goals was to examine the spectral emission of secondary species such as water vapor or carbon dioxide. The cold air stream injected in the plasma torch contained approximately 330 parts per million Of CO2, which is the natural CO2 concentration in atmospheric air at room temperature, and a small amount of water vapor with an estimated mole fraction of 3.8 x 10(exp -4). As can be seen from Figure 1, it was found that the measured spectrum exhibited intense spectral features due to the fundamental rovibrational bands of NO at 4.9 - 5.5 microns and the V(3) band of CO2 (antisymmetric stretch) at 4.2-4.8 microns. These observations confirmed the well-known fact that infrared signatures between 4.15 - 5.5 microns can be masked by radiative emission in the interceptor's bow-shock. Figure I also suggested that the range 3.2 - 4.15 microns did not contain any significant emission features (lines or continuum) that could mask IR signatures. However, the signal-to-noise level, close to one in that range, precluded definite conclusions. Thus, in an effort to further investigate the spectral emission in the range of interest to signature masking problem, new measurements were made with a higher signal-to-noise ratio and an extended wavelength range.

  10. Hg-Mask Coronagraph

    NASA Astrophysics Data System (ADS)

    Bourget, P.; Veiga, C. H.; Vieira Martins, R.; Assus, P.; Colas, F.

    In order to optimize the occulting process of a Lyot coronagraph and to provide a high dynamic range imaging, a new kind of occulting disk has been developed at the National Observatory of Rio de Janeiro. A mercury (Hg) drop glued onto an optical window by molecular cohesion and compressed by a pellicle film is used as the occulting disk. The minimum of the superficial tension potential function provides an optical precision (lambda/100) of the toric free surface of the mercury. This process provides a size control for the adaptation to the seeing conditions and to the apparent diameter of a resolved object, and in the case of adaptive optics, to the Airy diameter fraction needed. The occultation is a three dimensional process near the focal plane on the toric free surface that provides an apodization of the occultation. The Hg-Mask coronagraph has been projected for astrometric observations of faint satellites near to Jovian planets and works since 2000 at the 1.6 m telescope of the Pico dos Dias Observatory (OPD - Brazil).

  11. Mechanical alignment of substrates to a mask

    SciTech Connect

    Webb, Aaron P.; Carlson, Charles T.; Honan, Michael; Amato, Luigi G.; Grant, Christopher Neil; Strassner, James D.

    2016-11-08

    A plurality of masks is attached to the underside of a mask frame. This attachment is made such that each mask can independently move relative to the mask frame in three directions. This relative movement allows each mask to adjust its position to align with respective alignment pins disposed on a working surface. In one embodiment, each mask is attached to the mask frame using fasteners, where the fasteners have a shaft with a diameter smaller than the diameter of the mounting hole disposed on the mask. A bias element may be used to allow relative movement between the mask and the mask frame in the vertical direction. Each mask may also have kinematic features to mate with the respective alignment pins on the working surface.

  12. Influence of mask type and mask position on the effectiveness of bag-mask ventilation in a neonatal manikin.

    PubMed

    Deindl, Philipp; O'Reilly, Megan; Zoller, Katharina; Berger, Angelika; Pollak, Arnold; Schwindt, Jens; Schmölzer, Georg M

    2014-01-01

    Anatomical face mask with an air cushion rim might be placed accidentally in a false orientation on the newborn's face or filled with various amounts of air during neonatal resuscitation. Both false orientation as well as variable filling may reduce a tight seal and therefore hamper effective positive pressure ventilation (PPV). We aimed to measure the influence of mask type and mask position on the effectiveness of PPV. Twenty neonatal staff members delivered PPV to a modified, leak-free manikin. Resuscitation parameters were recorded using a self-inflatable bag PPV with an Intersurgical anatomical air cushion rim face mask (IS) and a size 0/1 Laerdal round face mask. Three different positions of the IS were tested: correct position, 90° and 180° rotation in reference to the midline of the face. IS masks in each correct position on the face but with different inflation of the air cushion (empty, 10, 20 and 30 mL). Mask leak was similar with mask rotation to either 90° or 180° but significantly increased from 27 (13-73) % with an adequate filled IS mask compared to 52 (16-83) % with an emptied air cushion rim. Anatomical-shaped face mask had similar mask leaks compared to round face mask. A wrongly positioned anatomical-shaped mask does not influence mask leak. Mask leak significantly increased once the air cushion rim was empty, which may cause failure in mask PPV.

  13. Vibrotactile masking through the body.

    PubMed

    D'Amour, Sarah; Harris, Laurence R

    2014-09-01

    Touches on one hand or forearm can affect tactile sensitivity at contralateral locations on the opposite side of the body. These interactions suggest an intimate connection between the two sides of the body. Here, we explore the effect of masking not across the body but through the body by measuring the effect of a masking stimulus on the back on the tactile sensitivity of the corresponding point on the front. Tactile sensitivity was measured on each side of the stomach, while vibrotactile masking stimulation was applied to one side of the front and to points on the back including the point directly behind the test point on the front. Results were compared to sensitivity, while vibrotactile stimulation was applied to a control site on the shoulder. A reduction in sensitivity of about .8 dB was found that required the masking stimulus to be within about 2 cm of the corresponding point on the back.

  14. Review of biomedical aspects of CB masks and their relationship to military performance. Technical report

    SciTech Connect

    Muza, S.R.

    1986-11-01

    This review describes the most important factors affecting military work performance while wearing a CB mask: (1) the additional inspiratory and expiratory breathing resistance; (2) increased external dead space; (3) thermal stress of the mask and hood; (4) restriction of functional vision; (5) hindrance of speech transmission and reception; (6) weight, size, and pressure on the face by the CB mask; (7) claustrophobic reactions, and (8) sleep loss and lack of nutrient intake due to long-term wear. In assessing the biomedical aspects of these factors, rather than making comparisons between specific models of CB masks, the review addresses these factors as they apply to CB masks in general.

  15. Block-based mask optimization for optical lithography.

    PubMed

    Ma, Xu; Song, Zhiyang; Li, Yanqiu; Arce, Gonzalo R

    2013-05-10

    Pixel-based optical proximity correction (PBOPC) methods have been developed as a leading-edge resolution enhancement technique (RET) for integrated circuit fabrication. PBOPC independently modulates each pixel on the reticle, which tremendously increases the mask's complexity and, at the same time, deteriorates its manufacturability. Most current PBOPC algorithms recur to regularization methods or a mask manufacturing rule check (MRC) to improve the mask manufacturability. Typically, these approaches either fail to satisfy manufacturing constraints on the practical product line, or lead to suboptimal mask patterns that may degrade the lithographic performance. This paper develops a block-based optical proximity correction (BBOPC) algorithm to pursue the optimal masks with manufacturability compliance, where the mask is shaped by a set of overlapped basis blocks rather than pixels. BBOPC optimization is formulated based on a vector imaging model, which is adequate for both dry lithography with lower numerical aperture (NA), and immersion lithography with hyper-NA. The BBOPC algorithm successively optimizes the main features (MF) and subresolution assist features (SRAF) based on a modified conjugate gradient method. It is effective at smoothing any unmanufacturable jogs along edges. A weight matrix is introduced in the cost function to preserve the edge fidelity of the printed images. Simulations show that the BBOPC algorithm can improve lithographic imaging performance while maintaining mask manufacturing constraints.

  16. Comparison of univariate and multivariate models for prediction of major and minor elements from laser-induced breakdown spectra with and without masking

    NASA Astrophysics Data System (ADS)

    Dyar, M. Darby; Fassett, Caleb I.; Giguere, Stephen; Lepore, Kate; Byrne, Sarah; Boucher, Thomas; Carey, CJ; Mahadevan, Sridhar

    2016-09-01

    This study uses 1356 spectra from 452 geologically-diverse samples, the largest suite of LIBS rock spectra ever assembled, to compare the accuracy of elemental predictions in models that use only spectral regions thought to contain peaks arising from the element of interest versus those that use information in the entire spectrum. Results show that for the elements Si, Al, Ti, Fe, Mg, Ca, Na, K, Ni, Mn, Cr, Co, and Zn, univariate predictions based on single emission lines are by far the least accurate, no matter how carefully the region of channels/wavelengths is chosen and despite the prominence of the selected emission lines. An automated iterative algorithm was developed to sweep through all 5485 channels of data and select the single region that produces the optimal prediction accuracy for each element using univariate analysis. For the eight major elements, use of this technique results in a 35% improvement in prediction accuracy; for minors, the improvement is 13%. The best wavelength region choice for any given univariate analysis is likely to be an inherent property of the specific training set that cannot be generalized. In comparison, multivariate analysis using partial least-squares (PLS) almost universally outperforms univariate analysis. PLS using all the same wavelength regions from the univariate analysis produces results that improve in accuracy by 63% for major elements and 3% for minor element. This difference is likely a reflection of signal to noise ratios, which are far better for major elements than for minor elements, and likely limit their prediction accuracy by any technique. We also compare predictions using specific wavelength ranges for each element against those employing all channels. Masking out channels to focus on emission lines from a specific element that occurs decreases prediction accuracy for major elements but is useful for minor elements with low signals and proportionally much higher noise; use of PLS rather than univariate

  17. A new suction mask to reduce leak during neonatal resuscitation: a manikin study.

    PubMed

    Lorenz, Laila; Maxfield, Dominic A; Dawson, Jennifer A; Kamlin, C Omar F; McGrory, Lorraine; Thio, Marta; Donath, Susan M; Davis, Peter G

    2016-09-01

    Leak around the face mask is a common problem during neonatal resuscitation. A newly designed face mask using a suction system to enhance contact between the mask and the infant's face might reduce leak and improve neonatal resuscitation. The aim of the study is to determine whether leak is reduced using the suction mask (Resusi-sure mask) compared with a conventional mask (Laerdal Silicone mask) in a manikin model. Sixty participants from different professional categories (neonatal consultants, fellows, registrars, nurses, midwives and students) used each face mask in a random order to deliver 2 min of positive pressure ventilation to a manikin. Delivered airway pressures were measured using a pressure line. Inspiratory and expiratory flows were measured using a flow sensor, and expiratory tidal volumes and mask leaks were derived from these values. A median (IQR) leak of 12.1 (0.6-39.0)% was found with the conventional mask compared with 0.7 (0.2-4.6)% using the suction mask (p=0.002). 50% of the participants preferred to use the suction mask and 38% preferred to use the conventional mask. There was no correlation between leak and operator experience. A new neonatal face mask based on the suction system reduced leak in a manikin model. Clinical studies to test the safety and effectiveness of this mask are needed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  18. 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

  19. Subdivisions with infinitely supported mask

    NASA Astrophysics Data System (ADS)

    Li, Song; Pan, Yali

    2008-04-01

    In this paper we investigate the convergence of subdivision schemes associated with masks being polynomially decay sequences. Two-scale vector refinement equations are the formwhere the vector of functions [phi]=([phi]1,E..,[phi]r)T is in and is polynomially decay sequence of rxr matrices called refinement mask. Associated with the mask a is a linear operator on given byBy using same methods in [B. Han, R. Q. Jia, Characterization of Riesz bases of wavelets generated from multiresolution analysis, manuscript]; [BE Han, Refinable functions and cascade algorithms in weighted spaces with infinitely supported masks, manuscript]; [R.Q. Jia, Q.T. Jiang, Z.W. Shen, Convergence of cascade algorithms associated with nonhomogeneous refinement equations, Proc. Amer. Math. Soc. 129 (2001) 415-427]; [R.Q. Jia, Convergence of vector subdivision schemes and construction of biorthogonal multiple wavelets, in: Advances in Wavelet, Hong Kong,1997, Springer, Singapore, 1998, pp. 199-227], a characterization of convergence of the sequences in the L2-norm is given, which extends the main results in [R.Q. Jia, S.D. Riemenschneider, D.X. Zhou, Vector subdivision schemes and multiple wavelets, Math. Comp. 67 (1998) 1533-1563] on convergence of the subdivision schemes associated with a finitely supported mask to the case in which mask a is polynomially decay sequence. As an application, we also obtain a characterization of smoothness of solutions of the refinement equation mentioned above for the case r=1.

  20. Increased dead space in face mask continuous positive airway pressure in neonates.

    PubMed

    Hishikawa, Kenji; Fujinaga, Hideshi; Ito, Yushi

    2017-01-01

    Continuous positive airway pressure (CPAP) by face mask is commonly performed in newborn resuscitation. We evaluated the effect of face mask CPAP on system dead space. Face mask CPAP increases dead space. A CPAP model study. We estimated the volume of the inner space of the mask. We devised a face mask CPAP model, in which the outlet of the mask was covered with plastic; and three modified face mask CPAP models, in which holes were drilled near to the cushion of the covered face mask to alter the air exit. We passed a continuous flow of 21% oxygen through each model and we controlled the inner pressure to 5 cmH2 O by adjusting the flow-relief valve. To evaluate the ventilation in the inner space of each model, we measured the oxygen concentration rise time, that is, the time needed for the oxygen concentration of each model to reach 35% after the oxygen concentration of the continuous flow was raised from 21% to 40%. The volume of inner space of the face mask was 38.3 ml. Oxygen concentration rise time in the face mask CPAP model was significantly longer at various continuous flow rates and points of the inner space of the face mask compared with that of the modified face mask CPAP model. Our study indicates that face mask CPAP leads to an increase in dead space and a decrease in ventilation efficiency under certain circumstances. Pediatr Pulmonol. 2017;52:107-111. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. New method of contour-based mask-shape compiler

    NASA Astrophysics Data System (ADS)

    Matsuoka, Ryoichi; Sugiyama, Akiyuki; Onizawa, Akira; Sato, Hidetoshi; Toyoda, Yasutaka

    2007-10-01

    We have developed a new method of accurately profiling 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, it is possible to create the profiles with much higher accuracy which is comparable with CD-SEM for semiconductor device CD measurement. 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. 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 for a DFM solution in which two dimensional data are extracted for an error free practical simulation by precise reproduction of a real mask shape in addition to the mask data simulation. The flow centering around the design data is fully automated and provides an environment where optimization and verification for fully automated model calibration with much less error is available. It also allows complete consolidation of input and output functions with an EDA system by constructing a design data oriented system structure. This method therefore is regarded as a strategic DFM approach in the semiconductor metrology.

  2. Masking mediated print defect visibility predictor

    NASA Astrophysics Data System (ADS)

    Jing, Xiaochen; Nachlieli, Hila; Shaked, Doron; Shiffman, Smadar; Allebach, Jan P.

    2012-01-01

    Banding is a well-known artifact produced by printing systems. It usually appears as lines perpendicular to the process direction of the print. Therefore, banding is an important print quality issue which has been analyzed and assessed by many researchers. However, little literature has focused on the study of the masking effect of content for this kind of print quality issue. Compared with other image and print quality research, our work is focused on the print quality of typical documents printed on a digital commercial printing press. In this paper, we propose a Masking Mediated Print Defect Visibility Predictor (MMPDVP) to predict the visibility of defects in the presence of customer content. The parameters of the algorithm are trained from ground-truth images that have been marked by subjects. The MMPDVP could help the press operator decide whether the print quality is acceptable for specific customer requirements. Ultimately, this model can be used to optimize the print-shop workflow.

  3. Mask specification guidelines in spacer patterning technology

    NASA Astrophysics Data System (ADS)

    Hashimoto, Kohji; Mukai, Hidefumi; Miyoshi, Seiro; Yamaguchi, Shinji; Mashita, Hiromitsu; Kobayashi, Yuuji; Kawano, Kenji; Hirano, Takashi

    2008-11-01

    We have studied both the mask CD specification and the mask defect specification for spacer patterning technology (SPT). SPT has the possibility of extending optical lithography to below 40nm half-pitch devices. Since SPT necessitates somewhat more complicated wafer process flow, the CD error and mask defect printability on wafers involve more process factors compared with conventional single-exposure process (SEP). This feature of SPT implies that it is very important to determine mask-related specifications for SPT in order to select high-end mask fabrication strategies; those are for mask writing tools, mask process development, materials, inspection tools, and so on. Our experimental studies reveal that both mask CD specification and mask defect specification are somehow relaxed from those in ITRS2007. This is most likely because SPT reduces mask CD error enhanced factor (MEF) and the reduction of line-width roughness (LWR).

  4. Stray-light sources from pupil mask edges and mitigation techniques for the TPF Coronagraph

    NASA Astrophysics Data System (ADS)

    Ceperley, Daniel; Neureuther, Andrew; Miller, Marshall; Lieber, Michael; Kasdin, Jeremy

    2006-06-01

    Stray-light sources from pupil plane masks that may limit Terrestrial Planet Finder Coronagraph (TPF-C) performance are characterized 1,2 and mitigation strategies are discussed to provide a guide for future development. Rigorous vector simulation with the Finite-Difference Time-Domain (FDTD) method is used to characterize waveguiding effects in narrow openings, sidewall interactions, manufacturing tool-marks, manufacturing roughness, mask tilt, and cross-wavelength performance of thick Silicon mask structures. These effects cause stray-light that is not accounted for in scalar thin-mask diffraction theory, the most important of which are sidewall interactions, waveguiding effects in narrow openings, and tilt. These results have been used to improve the scalar thin-mask theory used to simulate the TPF-C with the Integrated Telescope Model. 3 Of particular interest are simulations of 100m thick vertical sidewall openings that model features typically found on Ripple masks 4 fabricated by Reactive Ion Etching (RIE) processes. 5 This paper contributes fundamental data for systematically modeling these effects in end-to-end system simulation. Leakage straight through the mask material varies greatly with wavelength, especially in Silicon (an attractive mask material due to the precision manufacturing techniques developed by the IC industry). Coating Silicon with 200nm of Chrome effectively mitigates the leakage without causing additional scattering. Thick-mask diffraction differs from the predictions of scalar thin-mask theory because diffraction spreading is confined by the mask's sidewalls. This confinement can make a mask opening look electro-magnetically larger or smaller than designed, by up to 3λ per vertical sidewall on a 50μm thick mask yet this can be reduced an order of magnitude by undercutting the sidewalls 20°. These confinement effects are sensitive to mask tilt (if light reaches the sidewalls) which can lead to an imbalance in stray-light sources and

  5. Mask roughness induced LER: a rule of thumb -- paper

    SciTech Connect

    McClinton, Brittany; Naulleau, Patrick

    2010-03-12

    Much work has already been done on how both the resist and line-edge roughness (LER) on the mask affect the final printed LER. What is poorly understood, however, is the extent to which system-level effects such as mask surface roughness, illumination conditions, and defocus couple to speckle at the image plane, and currently factor into LER limits. Here, we propose a 'rule-of-thumb' simplified solution that provides a fast and powerful method to obtain mask roughness induced LER. We present modeling data on an older generation mask with a roughness of 230 pm as well as the ultimate target roughness of 50 pm. Moreover, we consider feature sizes of 50 nm and 22 nm, and show that as a function of correlation length, the LER peaks at the condition that the correlation length is approximately equal to the resolution of the imaging optic.

  6. Visual masking: past accomplishments, present status, future developments

    PubMed Central

    Breitmeyer, Bruno G.

    2008-01-01

    Visual masking, throughout its history, has been used as an investigative tool in exploring the temporal dynamics of visual perception, beginning with retinal processes and ending in cortical processes concerned with the conscious registration of stimuli. However, visual masking also has been a phenomenon deemed worthy of study in its own right. Most of the recent uses of visual masking have focused on the study of central processes, particularly those involved in feature, object and scene representations, in attentional control mechanisms, and in phenomenal awareness. In recent years our understanding of the phenomenon and cortical mechanisms of visual masking also has benefited from several brain imaging techniques and from a number of sophisticated and neurophysiologically plausible neural network models. Key issues and problems are discussed with the aim of guiding future empirical and theoretical research. PMID:20517494

  7. Rapid, accurate improvement in 3D mask representation via input geometry optimization and crosstalk

    NASA Astrophysics Data System (ADS)

    Fryer, David; Lam, Michael; Adam, Kostas; Clifford, Chris; Oliver, Mike; Zuniga, Christian; Sturtevant, John; Wang, ChangAn; Mansfield, Scott

    2014-03-01

    This paper extends the state of the art by demonstrating performance improvements in the Domain Decomposition Method (DDM) from a physical perturbation of the input mask geometry. Results from four testcases demonstrate that small, direct modifications in the input mask stack slope and edge location can result in model calibration and verification accuracy benefit of up to 30%. All final mask optimization results from this approach are shown to be valid within measurement accuracy of the dimensions expected from manufacture. We highlight the benefits of a more accurate description of the 3D EMF near field with crosstalk in model calibration and impact as a function of mask dimensions. The result is a useful technique to align DDM mask model accuracy with physical mask dimensions and scattering via model calibration.

  8. Contralateral tactile masking between forearms.

    PubMed

    D'Amour, Sarah; Harris, Laurence R

    2014-03-01

    Masking effects have been demonstrated in which tactile sensitivity is affected when one touch is close to another on the body surface. Such effects are likely a result of local lateral inhibitory circuits that sharpen the spatial tuning of a given tactile receptor. Mutually inhibitory pathways have also been demonstrated between cortical tactile maps of the two halves of the body. Occasional reports have indicated that touches on one hand or forearm can affect tactile sensitivity at contralateral locations. Here, we measure the spatial tuning and effect of posture on this contralateral masking effect. Tactile sensitivity was measured on one forearm, while vibrotactile masking stimulation was applied to the opposite arm. Results were compared to sensitivity while vibrotactile stimulation was applied to a control site on the right shoulder. Sensitivity on the forearm was reduced by over 3 dB when the arms were touching and by 0.52 dB when they were held parallel. The masking effect depended on the position of the masking stimulus. Its effectiveness fell off by 1 STD when the stimulus was 29 % of arm length from the corresponding contralateral point. This long-range inhibitory effect in the tactile system suggests a surprisingly intimate relationship between the two sides of the body.

  9. Dose masking feature for BNCT radiotherapy planning

    DOEpatents

    Cook, Jeremy L.; Wessol, Daniel E.; Wheeler, Floyd J.

    2000-01-01

    A system for displaying an accurate model of isodoses to be used in radiotherapy so that appropriate planning can be performed prior to actual treatment on a patient. The nature of the simulation of the radiotherapy planning for BNCT and Fast Neutron Therapy, etc., requires that the doses be computed in the entire volume. The "entire volume" includes the patient and beam geometries as well as the air spaces in between. Isodoses derived from the computed doses will therefore extend into the air regions between the patient and beam geometries and thus depict the unrealistic possibility that radiation deposition occurs in regions containing no physical media. This problem is solved by computing the doses for the entire geometry and then masking the physical and air regions along with the isodose contours superimposed over the patient image at the corresponding plane. The user is thus able to mask out (remove) the contour lines from the unwanted areas of the image by selecting the appropriate contour masking region from the raster image.

  10. Binaural effects in simultaneous room reflection masking

    NASA Astrophysics Data System (ADS)

    Buchholz, Joerg M.

    2005-04-01

    Masked thresholds (MT) for a single test reflection masked by a direct sound (200 ms long broadband noise) were measured dependent on the time delay of the reflection for diotic as well as dichotic stimulus presentation. In the diotic case, the direct sound and the test reflection were presented equally to both ears via headphones. In the dichotic case, an ITD of 0.5 ms was added to the test reflection. In order to focus on simultaneous masking effects, the reflection was truncated in such a way that it formed a common offset with the direct sound. For the diotic case, the resulting data showed a MT increase with increasing reflection delay and for the dichotic case a MT decrease with increasing reflection delay, producing an intercept between both curves at a reflection delay of 6-8 ms. Hence, negative BMLDs (up to -8 dB) were found for very early reflections and positive BMLDs (up to +8 dB) for later reflections, suggesting a binaural mechanism that suppresses very early reflections and enhances later reflections. The measurement results are discussed in the background of different auditory models.

  11. Fabless company mask technology approach: fabless but not fab-careless

    NASA Astrophysics Data System (ADS)

    Hisamura, Toshiyuki; Wu, Xin

    2009-10-01

    There are two different foundry-fabless working models in the aspect of mask. Some foundries have in-house mask facility while others contract with merchant mask vendors. Significant progress has been made in both kinds of situations. Xilinx as one of the pioneers of fabless semiconductor companies has been continually working very closely with both merchant mask vendors and mask facilities of foundries in past many years, contributed well in both technology development and benefited from corporations. Our involvement in manufacturing is driven by the following three elements: The first element is to understand the new fabrication and mask technologies and then find a suitable design / layout style to better utilize these new technologies and avoid potential risks. Because Xilinx has always been involved in early stage of advanced technology nodes, this early understanding and adoption is especially important. The second element is time to market. Reduction in mask and wafer manufacturing cycle-time can ensure faster time to market. The third element is quality. Commitment to quality is our highest priority for our customers. We have enough visibility on any manufacturing issues affecting the device functionality. Good correlation has consistently been observed between FPGA speed uniformity and the poly mask Critical Dimension (CD) uniformity performance. To achieve FPGA speed uniformity requirement, the manufacturing process as well as the mask and wafer CD uniformity has to be monitored. Xilinx works closely with the wafer foundries and mask suppliers to improve productivity and the yield from initial development stage of mask making operations. As an example, defect density reduction is one of the biggest challenges for mask supplier in development stage to meet the yield target satisfying the mask cost and mask turn-around-time (TAT) requirement. Historically, masks were considered to be defect free but at these advanced process nodes, that assumption no longer

  12. Dissolution methodology for taste masked oral dosage forms.

    PubMed

    Gittings, Sally; Turnbull, Neil; Roberts, Clive J; Gershkovich, Pavel

    2014-01-10

    Conventional adult dosage forms are often not suitable for the paediatric and geriatric populations due to either swallowing difficulties or patient repulsion and a requirement for tailored dosing to individual compliance or physiological needs. Alternative formulations are available; however these often require the incorporation of more complex taste masking techniques. One approach to taste masking is to reduce contact between the bitter Active Pharmaceutical Ingredient (API) and oral cavity taste bud regions. This is achieved by hindering release in the oral cavity, or including competitive inhibition of bitter sensation for example by using flavours or sweeteners. There may also be other sensational complications from the API such as residual burning, reflux or metallic taste sensations to deal with. In vitro dissolution testing is employed to elucidate taste masking capability by quantifying release of the drug in simulated oral cavity conditions. Dissolution testing approaches may also be used to potentially predict or quantify the effect of the taste masking technique on the resultant pharmacokinetic profile. The present review investigates the anatomy and physiology of the oral cavity and current approaches to taste masking. In vitro dissolution methodologies adopted in the evaluation of taste masked formulations are discussed for their relative merits and drawbacks. A vast array of methodologies has been employed, with little agreement between approaches, and a lack of biorelevance. Future directions in dissolution methodology such as TNO Intestinal Model (TIM) and the Artificial Stomach and Duodenum model (ASD) are also discussed. © 2013.

  13. Temporal integration in vision: masking can aid detection.

    PubMed

    Swift, Dan J

    2013-04-01

    Temporal form-part integration is the process whereby two discrete sets of stimuli, presented at different times, are perceived by the visual system as a single integrated percept. Dixon and Di Lollo (Cognitive Psychology 26(1):33-63, 1994) proposed a temporal correlation model that was able to quantitatively account for a number of findings related to both form-part integration tasks and partial report. The present study demonstrates a novel approach to form-part integration--the addition of a whole-field mask stimulus at the termination of the second set of stimuli. According to an extension of the correlation model, the mask stimulus should reduce the visual system's response to the trailing display, thus increasing the relative overlap of the two displays, fostering integration. Experiment 1 supported this hypothesis, showing a maximum benefit when the mask followed the trailing display immediately, as opposed to after a delay of 60 ms. Experiment 2 showed that this same mask actually did yield worse performance when presented immediately after a single set of stimuli. The third experiment collected detailed data for a few observers over a larger number of mask delays. Taken together, these experiments provide a rare example of masking degrading a target stimulus, and yet aiding perception.

  14. Fixing the focus shift caused by 3D mask diffraction

    NASA Astrophysics Data System (ADS)

    Yenikaya, Bayram; Chuyeshov, Constantin; Bakir, Onur; Han, Youngae

    2014-03-01

    As the feature sizes printed with optical lithography get smaller, Kirchhoff's thin mask approximation used in full chip optical proximity corrections (OPC) fails to yield acceptable accuracy due to thick mask diffraction effects. One of the most observed effects of the thick mask diffraction is that it creates different focus shift for different patterns. When Bossung curves (CD plots with respect to defocus) of various patterns are observed from rigorous simulations and from actual wafer data one can notice that each pattern has a different best focus. Depending on the pattern, Bossung curves can be offset in either positive or negative direction. This significantly reduces the common depth of focus (DOF) for which all patterns print with acceptable fidelity. Even though each pattern by itself may have an acceptable DOF, the common DOF may not be acceptable. Several extensions to the thin mask approximation have been developed that model this behavior accurately, such as boundary layer approximations and domain decomposition methods. These methods provide a more accurate approximation than the thin mask model while still being computationally efficient to be useful for full chip OPC. Even though these approximations model and predict the focus shift accurately, to the best knowledge of the authors no method has been published to use these modeling capabilities to automatically fix this focus shift during OPC. In this paper we provide an optimization method to significantly reduce focus shift due to 3D mask effects during OPC. We show that our 3D mask model can predict this focus shift fairly accurately and we also demonstrate how we use this model in OPC to reduce focus shift, which significantly improves the common DOF for the entire layout.

  15. 1999 mask industry quality assessment

    NASA Astrophysics Data System (ADS)

    Grenon, Brian J.

    1999-12-01

    This paper will summarize the results of the seventh annual mask industry assessment survey. This year there were 12 respondents. The specific responses from the participants have been kept confidential by having the participants send their responses to Arthur Anderson & Company prior to data evaluation. This year we will report the following information: total shipments, total customer returns, mask survival rate, delivery performance, average throughput time and safety records. The data reported will be for the period of 3Q98 through 2Q98. Additionally, we will present any trends that may be apparent in the data. This year's participants are Align-Rite, Dai Nippon Printing, IBM Essex Junction, Photronics/Toppan Texas, Compugraphics, DuPont Photomasks, Northrup-Grumman, Infineon, Taiwan Mask Corporation (TMC), Taiwan Semiconductor Manufacturing Corporation (TSMC) and Innova. In order to maintain some consistency, the format that has been used from past years will be maintained when possible.

  16. Informational masking and musical training

    NASA Astrophysics Data System (ADS)

    Oxenham, Andrew J.; Fligor, Brian J.; Mason, Christine R.; Kidd, Gerald

    2003-09-01

    The relationship between musical training and informational masking was studied for 24 young adult listeners with normal hearing. The listeners were divided into two groups based on musical training. In one group, the listeners had little or no musical training; the other group was comprised of highly trained, currently active musicians. The hypothesis was that musicians may be less susceptible to informational masking, which is thought to reflect central, rather than peripheral, limitations on the processing of sound. Masked thresholds were measured in two conditions, similar to those used by Kidd et al. [J. Acoust. Soc. Am. 95, 3475-3480 (1994)]. In both conditions the signal was comprised of a series of repeated tone bursts at 1 kHz. The masker was comprised of a series of multitone bursts, gated with the signal. In one condition the frequencies of the masker were selected randomly for each burst; in the other condition the masker frequencies were selected randomly for the first burst of each interval and then remained constant throughout the interval. The difference in thresholds between the two conditions was taken as a measure of informational masking. Frequency selectivity, using the notched-noise method, was also estimated in the two groups. The results showed no difference in frequency selectivity between the two groups, but showed a large and significant difference in the amount of informational masking between musically trained and untrained listeners. This informational masking task, which requires no knowledge specific to musical training (such as note or interval names) and is generally not susceptible to systematic short- or medium-term training effects, may provide a basis for further studies of analytic listening abilities in different populations.

  17. Production mask composition checking flow

    NASA Astrophysics Data System (ADS)

    Ma, Shou-Yuan; Yang, Chuen-Huei; Tsai, Joe; Wang, Alice; Lin, Roger; Lee, Rachel; Deng, Erwin; Lin, Ling-Chieh; Liao, Hung-Yueh; Tsai, Jenny; Bowhill, Amanda; Vu, Hien; Russell, Gordon

    2016-05-01

    The mask composition checking flow is an evolution of the traditional mask rule check (MRC). In order to differentiate the flow from MRC, we call it Mask Data Correctness Check (MDCC). The mask house does MRC only to identify process limitations including writing, etching, metrology, etc. There still exist many potential errors that could occur when the frame, main circuit and dummies all together form a whole reticle. The MDCC flow combines the design rule check (DRC) and MRC concepts to adapt to the complex patterns in today's wafer production technologies. Although photomask data has unique characteristics, the MRC tool in Calibre® MDP can easily achieve mask composition by using the Extended MEBES job deck (EJB) format. In EJB format, we can customize the combination of any input layers in an IC design layout format, such as OASIS. Calibre MDP provides section-based processing for many standard verification rule format (SVRF) commands that support DRC-like checks on mask data. Integrating DRC-like checking with EJB for layer composition, we actually perform reticle-level DRC, which is the essence of MDCC. The flow also provides an early review environment before the photomask pattern files are available. Furthermore, to incorporate the MDCC in our production flow, runtime is one of the most important indexes we consider. When the MDCC is included in the tape-out flow, the runtime impact is very limited. Calibre, with its multi-threaded processes and good scalability, is the key to achieving acceptable runtime. In this paper, we present real case runtime data for 28nm and 14nm technology nodes, and prove the practicability of placing MDCC into mass production.

  18. Phase-shift mask applications

    NASA Astrophysics Data System (ADS)

    Buck, Peter D.; Rieger, Michael L.

    1991-07-01

    Phase-shifted masks (PSMs) promise significant performance benefits for conventional optical lithography. By simultaneously enhancing resolution and depth of focus (DOF), some PSM techniques offer lithography improvements equivalent to more than a 30% reduction of exposure wavelength. Existing wafer exposure equipment can be adapted to PSM use without extensive modification. However, widespread use of PSM technology must await the creation of a PSM infrastructure, including automated generation of PSM patterns, new mask-making materials, and production worthy PSM manufacturing equipment and methods. Modified CAD software, phase layer mask exposure, phase layer deposition, etch, inspection, repair, and other supporting equipment are still in research or development phases. The integration of PSM methodologies and processes to mask and wafer production facilities has not yet begun. In this paper PSM manufacturing and application issues will be examined, with emphasis on PSM reticle printing, PSM reticle requirements and PSM manufacturing alternatives. The authors report on the performance of a scanned laser mask lithography system optimized for printing multilayer phase-shift masks. This system leverages the sub-half micron printing performance of the ATEQ CORE-2500 combined with an optical alignment system. The use of 363.8 nm exposure wavelength offers significant advantages for making PSMs. Chrome alignment marks under dielectric phase and resist layers are accurately and nondestructively acquired with a nonactinic illumination system. The exposure wavelength, near i-line, does not cause or react to dielectric substrate charge. Optimum performance is achieved with common i-line resists which also provide ideal process performance for phase layer deposition and dry etching.

  19. The man in the mask.

    PubMed

    Zugibe, F T; Costello, J T; Breithaupt, M K

    1987-05-01

    A skeletonized body, wearing a black leather bondage mask, was found in a Revolutionary War smokehouse cave with two bullet holes in the back of the head. The body was skeletonized up to the maxillary area but the head region under the mask was well preserved and permitted a positive visual identification. There was evidence that the body had been eaten by small animals and subsequently burned. Investigations into this brutal murder revealed a tale of a bizarre sadomasochistic ritual that attained national prominence.

  20. Perceptual masking of boar taint in Swedish fermented sausages.

    PubMed

    Stolzenbach, Sandra; Lindahl, Gunilla; Lundström, Kerstin; Chen, Gang; Byrne, Derek V

    2009-04-01

    Surgical castration of male piglets has traditionally been practiced to avoid development of boar taint in pork meat which can occur if entire male pigs are raised. Boar taint is commonly characterised as exhibiting the odour and flavour of urine and manure. This study involves sensory characterisation of the possibilities to mask boar taint in meat from entire male pigs by fermentation and smoking to maintain high sensory quality in meat products if castration is prohibited. Model and commercial type Swedish fermented sausage products based on low or high levels of boar tainted fat, three different starter cultures and two different levels of smoking were studied. In the model sausages, liquid smoke masked the perception of boar taint. In contrast, the smoking procedure of the commercial sausages was insufficient to totally mask the perception of boar taint. In both the model and commercial sausages, the aroma development from the starter cultures lowered the perception of boar taint but was insufficient for total perceptual masking. Due to the total masking effect of smoking in the model sausages, it was clear that smoke may present a potential solution to remove the perception of boar taint in fermented sausages if the smoking procedure is optimised.

  1. The Marine Mask of War

    DTIC Science & Technology

    2011-11-10

    America’s Army. To the Marines, it is teamwork and the subordination of the individual to the common good of the unit. First person pronouns are shunned...As demonstrated over the last decade, this versatility and cost effectiveness is a good deal for the American taxpayer. Having examined the Mask

  2. Imaging With the IBIS Mask

    NASA Astrophysics Data System (ADS)

    Berná, J. A.; Torrejón, J. M.; Bernabeu, G.

    2001-03-01

    We present very preliminary results on the imaging capabilities of the IBIS instrument, the gamma ray imager on board ESA's INTEGRAL satellite, regarding the coded mask subsystem. For this purpose we perform a simulation of a pointed observation to the Galactic Centre region and investigate the detection of the most prominent sources.

  3. Ultrahigh efficiency EUV contact-hole printing with chromeless phase shift mask

    NASA Astrophysics Data System (ADS)

    Naulleau, Patrick; Anderson, Christopher N.; Chao, Weilun; Goldberg, Kenneth A.; Gullikson, Eric; Salmassi, Farhad; Wojdyla, Antoine

    2016-05-01

    Contact-hole layer patterning is expected to be one of the first applications for EUV lithography. Conventional darkfield absorber masks, however, are extremely inefficient for these layers, placing even more burden on the already challenging source power demands. To address this concern, a checkerboard phase shift mask configuration has been proposed yielding theoretical throughput gains of 5x assuming a thin-mask modeling. In this manuscript we describe the fabrication of such a mask and demonstrate its imaging performance using the SHARP EUV microscope and MET exposure tool at Lawrence Berkeley National Laboratory. For 25-nm dense features, the phase shift mask was shown to provide a throughput gain of 8x based on SHARP and 7x based on the Berkeley MET. The higher then predicted gain is expected to be due to the fact that the thin mask modeling used in the initial prediction misses shadowing effects.

  4. Masked Hypertension in Diabetes Mellitus

    PubMed Central

    Franklin, Stanley S.; Thijs, Lutgarde; Li, Yan; Hansen, Tine W.; Boggia, José; Liu, Yanping; Asayama, Kei; Björklund-Bodegård, Kristina; Ohkubo, Takayoshi; Jeppesen, Jørgen; Torp-Pedersen, Christian; Dolan, Eamon; Kuznetsova, Tatiana; Stolarz-Skrzypek, Katarzyna; Tikhonoff, Valérie; Malyutina, Sofia; Casiglia, Edoardo; Nikitin, Yuri; Lind, Lars; Sandoya, Edgardo; Kawecka-Jaszcz, Kalina; Filipovský, Jan; Imai, Yutaka; Wang, Jiguang; Ibsen, Hans; O’Brien, Eoin; Staessen, Jan A.

    2013-01-01

    Although distinguishing features of masked hypertension in diabetics are well known, the significance of antihypertensive treatment on clinical practice decisions has not been fully explored. We analyzed 9691 subjects from the population-based 11-country International Database on Ambulatory Blood Pressure in Relation to Cardiovascular Outcomes. Prevalence of masked hypertension in untreated normotensive participants was higher (P<0.0001) among 229 diabetics (29.3%, n=67) than among 5486 nondiabetics (18.8%, n=1031). Over a median of 11.0 years of follow-up, the adjusted risk for a composite cardiovascular end point in untreated diabetic-masked hypertensives tended to be higher than in normotensives (hazard rate [HR], 1.96; 95% confidence interval [CI], 0.97–3.97; P=0.059), similar to untreated stage 1 hypertensives (HR, 1.07; CI, 0.58–1.98; P=0.82), but less than stage 2 hypertensives (HR, 0.53; CI, 0.29–0.99; P=0.048). In contrast, cardiovascular risk was not significantly different in antihypertensive-treated diabetic-masked hypertensives, as compared with the normotensive comparator group (HR, 1.13; CI, 0.54–2.35; P=0.75), stage 1 hypertensives (HR, 0.91; CI, 0.49–1.69; P=0.76), and stage 2 hypertensives (HR, 0.65; CI, 0.35–1.20; P=0.17). In the untreated diabetic-masked hypertensive population, mean conventional systolic/diastolic blood pressure was 129.2±8.0/76.0±7.3 mm Hg, and mean daytime systolic/diastolic blood pressure 141.5±9.1/83.7±6.5 mm Hg. In conclusion, masked hypertension occurred in 29% of untreated diabetics, had comparable cardiovascular risk as stage 1 hypertension, and would require considerable reduction in conventional blood pressure to reach daytime ambulatory treatment goal. Importantly, many hypertensive diabetics when receiving antihypertensive therapy can present with normalized conventional and elevated ambulatory blood pressure that mimics masked hypertension. PMID:23478096

  5. "The Mask Who Wasn't There": Visual Masking Effect with the Perceptual Absence of the Mask

    ERIC Educational Resources Information Center

    Rey, Amandine Eve; Riou, Benoit; Muller, Dominique; Dabic, Stéphanie; Versace, Rémy

    2015-01-01

    Does a visual mask need to be perceptually present to disrupt processing? In the present research, we proposed to explore the link between perceptual and memory mechanisms by demonstrating that a typical sensory phenomenon (visual masking) can be replicated at a memory level. Experiment 1 highlighted an interference effect of a visual mask on the…

  6. "The Mask Who Wasn't There": Visual Masking Effect with the Perceptual Absence of the Mask

    ERIC Educational Resources Information Center

    Rey, Amandine Eve; Riou, Benoit; Muller, Dominique; Dabic, Stéphanie; Versace, Rémy

    2015-01-01

    Does a visual mask need to be perceptually present to disrupt processing? In the present research, we proposed to explore the link between perceptual and memory mechanisms by demonstrating that a typical sensory phenomenon (visual masking) can be replicated at a memory level. Experiment 1 highlighted an interference effect of a visual mask on the…

  7. Clinical bitterness masking test for phantogeusia.

    PubMed

    Ishimaru, T; Hatanaka, S; Miwa, T; Furukawa, M

    2001-01-01

    It is difficult to determine the reason why a patient complains of a bitter taste when their mouth is empty. We examined a new diagnostic test using a bitterness masking substance. The bitterness masking substance, 'Benecoat BMI-60' (hereafter BMI-60), is a masking substance specific to the taste cells' bitterness receptors. After patients gargled with BMI-60 solutions, the phantom sensation of bitterness was masked in some patients, but was not masked in others. Bitter substances in saliva seemed to be masked by BMI-60, but bitterness did not seem to be masked when the locus of the phantom sensation was within the peripheral nerve and/or the brain. The bitterness masking test is useful for diagnosis of the phantom sensation of bitter taste.

  8. Vertical Feature Mask Feature Classification Flag Extraction

    Atmospheric Science Data Center

    2013-03-28

    ... Feature Mask Feature Classification Flag Extraction This routine demonstrates extraction of the feature type information stored in a ... Vertical Feature Mask Feature Classification Flag Extraction routine  (5 KB) Interactive Data Language (IDL) is available from  ...

  9. Physiological functioning of the ear and masking

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The physiological functions of the ear and the role masking plays in speech communication are examined. Topics under investigation include sound analysis of the ear, the aural reflex, and various types of noise masking.

  10. An instructional video enhanced bag-mask ventilation quality during simulated newborn resuscitation.

    PubMed

    Deindl, Philipp; Schwindt, Jens; Berger, Angelika; Schmölzer, Georg M

    2015-01-01

    Approximately 20% of newborns infants need respiratory support at birth. This study evaluated whether video-based education could improve quality of positive pressure ventilation (PPV) performed by inexperienced staff during neonatal resuscitation. Fourth-year medical students were randomly paired and instructed to give PPV to a modified manikin as single-person resuscitators and as two-person-paired resuscitators using either an air cushion rim mask or a round mask before and after watching a self-instructional video. Airway pressure, gas flow, tidal volume and mask leak were recorded. PPV performance quality was analysed using video recording. Mask leak was lower during one-person ventilation when using the air cushion rim mask (56 ± 16%) compared to the round mask (71 ± 19%). Round mask leak during one-person ventilation was significantly lower when using the two point top hold in contrast to the 'o.k.' rim hold (before training: 63 ± 22% vs. 72 ± 18%, after training: 57 ± 17% vs. 77 ± 12%). Watching a self-instructional video improved performance quality scores of both correct head positioning, and the quality of airway manoeuvres compared to baseline, however mask leak was not significantly reduced. A self-instructional video significantly improved bag mask PPV performance in inexperienced providers but did not improve mask leak in a model of neonatal resuscitation. ©2014 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  11. Spatial and Temporal Visual Masking and Visibility.

    DTIC Science & Technology

    1984-10-01

    and by showing that familarity with a random mask pattern can produce such a criterion change. In this paper we present evidence for the existence of...conditions. The data presented in this paper are typically test thresholds for a variety of mask contrasts. The various mask contrasts were always...nonlinearity preserves the ordering of these states. In this paper , we shall develop the following hypothesis. If a test pattern is masked by noise

  12. How do different brands of size 1 laryngeal mask airway compare with face mask ventilation in a dedicated laryngeal mask airway teaching manikin?

    PubMed

    Tracy, Mark Brian; Priyadarshi, Archana; Goel, Dimple; Lowe, Krista; Huvanandana, Jacqueline; Hinder, Murray

    2017-08-11

    International neonatal resuscitation guidelines recommend the use of laryngeal mask airway (LMA) with newborn infants (≥34 weeks' gestation or >2 kg weight) when bag-mask ventilation (BMV) or tracheal intubation is unsuccessful. Previous publications do not allow broad LMA device comparison. To compare delivered ventilation of seven brands of size 1 LMA devices with two brands of face mask using self-inflating bag (SIB). 40 experienced neonatal staff provided inflation cycles using SIB with positive end expiratory pressure (PEEP) (5 cmH2O) to a specialised newborn/infant training manikin randomised for each LMA and face mask. All subjects received prior education in LMA insertion and BMV. 12 415 recorded inflations for LMAs and face masks were analysed. Leak detected was lowest with i-gel brand, with a mean of 5.7% compared with face mask (triangular 42.7, round 35.7) and other LMAs (45.5-65.4) (p<0.001). Peak inspiratory pressure was higher with i-gel, with a mean of 28.9 cmH2O compared with face mask (triangular 22.8, round 25.8) and other LMAs (14.3-22.0) (p<0.001). PEEP was higher with i-gel, with a mean of 5.1 cmH2O compared with face mask (triangular 3.0, round 3.6) and other LMAs (0.6-2.6) (p<0.001). In contrast to other LMAs examined, i-gel had no insertion failures and all users found i-gel easy to use. This study has shown dramatic performance differences in delivered ventilation, mask leak and ease of use among seven different brands of LMA tested in a manikin model. This coupled with no partial or complete insertion failures and ease of use suggests i-gel LMA may have an expanded role with newborn resuscitation as a primary resuscitation device. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  13. Sandwich Priming: A Method for Overcoming the Limitations of Masked Priming by Reducing Lexical Competitor Effects

    ERIC Educational Resources Information Center

    Lupker, Stephen J.; Davis, Colin J.

    2009-01-01

    An orthographically similar masked nonword prime facilitates responding in a lexical decision task (Forster & Davis, 1984). Recently, this masked priming paradigm has been used to evaluate models of orthographic coding--models that attempt to quantify prime-target similarity. One general finding is that priming effects often do not occur when…

  14. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask. (a) Identification. A nonrebreathing mask is a device fitting over a patient's face to administer oxygen. It utilizes... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570...

  15. Masks: Escape to/from Reality.

    ERIC Educational Resources Information Center

    Kavett, Hyman

    1981-01-01

    Explains the significance of masks in ethnographic and cultural research and suggests 24 activities intended for use by social studies classroom teachers as they teach about masks. Activities include projecting slides onto students' bodies and faces, directing students to create masks from old clothing and rags, cutting faces from magazines, and…

  16. Inadequate face mask ventilation--clinical applications.

    PubMed

    Goranović, Tatjana; Milić, Morena; Holjevac, Jadranka Katancić; Maldini, Branka; Sakić, Katarina

    2010-09-01

    Face mask ventilation is a life saving technique. This article will review aetiology and patophysiological consequences of inadequate mask ventilation. The main focus will be on circulatory changes during induction of anesthesia, before and in a short period after intubation that could be attributed to inadequate mask ventilation in humans.

  17. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask. (a) Identification. A nonrebreathing mask is a device fitting over a patient's face to administer oxygen. It utilizes... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570...

  18. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask. (a) Identification. A nonrebreathing mask is a device fitting over a patient's face to administer oxygen. It utilizes... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570...

  19. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and... ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a device placed over a patient's nose, mouth, or tracheostomy to administer oxygen or aerosols. (b)...

  20. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and... ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a device placed over a patient's nose, mouth, or tracheostomy to administer oxygen or aerosols. (b)...

  1. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and... ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a device placed over a patient's nose, mouth, or tracheostomy to administer oxygen or aerosols. (b)...

  2. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and... ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a device placed over a patient's nose, mouth, or tracheostomy to administer oxygen or aerosols. (b)...

  3. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and... ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a device placed over a patient's nose, mouth, or tracheostomy to administer oxygen or aerosols. (b)...

  4. 21 CFR 868.5600 - Venturi mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Venturi mask. 868.5600 Section 868.5600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5600 Venturi mask. (a) Identification. A venturi mask is...

  5. 21 CFR 868.5600 - Venturi mask.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Venturi mask. 868.5600 Section 868.5600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5600 Venturi mask. (a) Identification. A venturi mask is a...

  6. Method for mask repair using defect compensation

    DOEpatents

    Sweeney, Donald W.; Ray-Chaudhuri, Avijit K.

    2001-01-01

    A method for repair of amplitude and/or phase defects in lithographic masks. The method involves modifying or altering a portion of the absorber pattern on the surface of the mask blank proximate to the mask defect to compensate for the local disturbance (amplitude or phase) of the optical field due to the defect.

  7. 47 CFR 90.210 - Emission masks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Emission masks. 90.210 Section 90.210... MOBILE RADIO SERVICES General Technical Standards § 90.210 Emission masks. Except as indicated elsewhere... emission masks outlined in this section. Unless otherwise stated, per paragraphs (d)(4), (e)(4), and (m)...

  8. 47 CFR 90.210 - Emission masks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Emission masks. 90.210 Section 90.210... MOBILE RADIO SERVICES General Technical Standards § 90.210 Emission masks. Except as indicated elsewhere... emission masks outlined in this section. Unless otherwise stated, per paragraphs (d)(4), (e)(4), and (o)...

  9. 47 CFR 90.210 - Emission masks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Emission masks. 90.210 Section 90.210... MOBILE RADIO SERVICES General Technical Standards § 90.210 Emission masks. Except as indicated elsewhere... emission masks outlined in this section. Unless otherwise stated, per paragraphs (d)(4), (e)(4), and (o)...

  10. 47 CFR 90.210 - Emission masks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emission masks. 90.210 Section 90.210... MOBILE RADIO SERVICES General Technical Standards § 90.210 Emission masks. Except as indicated elsewhere... emission masks outlined in this section. Unless otherwise stated, per paragraphs (d)(4), (e)(4), and (m)...

  11. 47 CFR 90.210 - Emission masks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Emission masks. 90.210 Section 90.210... MOBILE RADIO SERVICES General Technical Standards § 90.210 Emission masks. Except as indicated elsewhere... emission masks outlined in this section. Unless otherwise stated, per paragraphs (d)(4), (e)(4), and (m)...

  12. Object Substitution Masking Induced by Illusory Masks: Evidence for Higher Object-Level Locus of Interference

    ERIC Educational Resources Information Center

    Hirose, Nobuyuki; Osaka, Naoyuki

    2009-01-01

    A briefly presented target can be rendered invisible by a lingering sparse mask that does not even touch it. This form of visual backward masking, called object substitution masking, is thought to occur at the object level of processing. However, it remains unclear whether object-level interference alone produces substitution masking because…

  13. Object Substitution Masking Induced by Illusory Masks: Evidence for Higher Object-Level Locus of Interference

    ERIC Educational Resources Information Center

    Hirose, Nobuyuki; Osaka, Naoyuki

    2009-01-01

    A briefly presented target can be rendered invisible by a lingering sparse mask that does not even touch it. This form of visual backward masking, called object substitution masking, is thought to occur at the object level of processing. However, it remains unclear whether object-level interference alone produces substitution masking because…

  14. Trade-off between inverse lithography mask complexity and lithographic performance

    NASA Astrophysics Data System (ADS)

    Kim, Byung-Gook; Suh, Sung Soo; Kim, Byung-Sung; Woo, Sang-Gyun; Cho, Han-Ku; Tolani, Vikram; Dai, Grace; Irby, Dave; Wang, Kechang; Xiao, Guangming; Kim, David; Baik, Ki-Ho; Gleason, Bob

    2009-04-01

    Improvements in resolution of exposure systems have not kept pace with increasing density of semiconductor products. In order to keep shrinking circuits using equipment with the same basic resolution, lithographers have turned to options such as double-patterning, and have moved beyond model-based OPC in the search for optimal mask patterns. Inverse Lithography Technology (ILT) is becoming one of the strong candidates in 32nm & below single patterning, low-k1 lithography regime. It enables computation of optimum mask patterns to minimize deviations of images from their targets not only at nominal but also over a range of process variations, such as dose, defocus, and mask CD errors. When optimizing for a factor, such as process window, more complex mask patterns are often necessary to achieve the desired depth of focus. Complex mask patterns require more shots when written with VSB systems, increasing the component of mask cost associated with writing time. It can also be more difficult to inspect or repair certain types of complex patterns. Inspection and repair may take more time, or require more expensive equipment compared to the case with simpler masks. For these reasons, we desire to determine the simplest mask patterns that meet necessary lithographic manufacturing objectives. Luminescent ILT provides means to constrain complexity of mask solutions, each of which is optimized to meet lithographic objectives within the bounds of the constraints. Results presented here show trade-offs to process window performance with varying degrees of mask complexity. The paper details ILT mask simplification schemes on contact arrays and random logic, comparing process window trade-offs in each case. Ultimately this method enables litho and mask engineers balance lithographic requirements with mask manufacturing complexity and related cost.

  15. Performance of GFIS mask repair system for various mask materials

    NASA Astrophysics Data System (ADS)

    Aramaki, Fumio; Kozakai, Tomokazu; Matsuda, Osamu; Yasaka, Anto; Yoshikawa, Shingo; Kanno, Koichi; Miyashita, Hiroyuki; Hayashi, Naoya

    2014-10-01

    We have developed a new focused ion beam (FIB) technology using a gas field ion source (GFIS) for mask repair. Meanwhile, since current high-end photomasks do not have high durability in exposure nor cleaning, some new photomask materials are proposed. In 2012, we reported that our GFIS system had repaired a representative new material "A6L2". It is currently expected to extend the application range of GFIS technology for various new materials and various defect shapes. In this study, we repaired a single bridge, a triple bridge and a missing hole on a phase shift mask (PSM) of "A6L2", and also repaired single bridges on a binary mask of molybdenum silicide (MoSi) material "W4G" and a PSM of high transmittance material "SDC1". The etching selectivity between those new materials and quartz were over 4:1. There were no significant differences of pattern shapes on scanning electron microscopy (SEM) images between repair and non-repair regions. All the critical dimensions (CD) at repair regions were less than +/-3% of those at normal ones on an aerial image metrology system (AIMS). Those results demonstrated that GFIS technology is a reliable solution of repairing new material photomasks that are candidates for 1X nm generation.

  16. Integrating RET and mask manufacturability in memory designs for local interconnect for sub-100nm trenches

    NASA Astrophysics Data System (ADS)

    Kachwala, Nishrin; Iandolo, Walter; Brist, Travis; Farnbach, Rick

    2005-05-01

    Model based OPC for low k1 lithography has a large impact on mask cost, and hence must be optimized with respect to mask manufacturability and mask cost without sacrificing device performance. Design IP blocks not designed with the lithography process in mind (not "litho friendly") require more complex RET/OPC solutions, which can in turn result in unnecessary increases in the mask cost and turn around time. These blocks are typically replicated many times across a design and can therefore have a compounding effect.

  17. Rapid mask prototyping for microfluidics.

    PubMed

    Maisonneuve, B G C; Honegger, T; Cordeiro, J; Lecarme, O; Thiry, T; Fuard, D; Berton, K; Picard, E; Zelsmann, M; Peyrade, D

    2016-03-01

    With the rise of microfluidics for the past decade, there has come an ever more pressing need for a low-cost and rapid prototyping technology, especially for research and education purposes. In this article, we report a rapid prototyping process of chromed masks for various microfluidic applications. The process takes place out of a clean room, uses a commercially available video-projector, and can be completed in less than half an hour. We quantify the ranges of fields of view and of resolutions accessible through this video-projection system and report the fabrication of critical microfluidic components (junctions, straight channels, and curved channels). To exemplify the process, three common devices are produced using this method: a droplet generation device, a gradient generation device, and a neuro-engineering oriented device. The neuro-engineering oriented device is a compartmentalized microfluidic chip, and therefore, required the production and the precise alignment of two different masks.

  18. Ligand-induced Epitope Masking

    PubMed Central

    Mould, A. Paul; Askari, Janet A.; Byron, Adam; Takada, Yoshikazu; Jowitt, Thomas A.; Humphries, Martin J.

    2016-01-01

    We previously demonstrated that Arg-Gly-Asp (RGD)-containing ligand-mimetic inhibitors of integrins are unable to dissociate pre-formed integrin-fibronectin complexes (IFCs). These observations suggested that amino acid residues involved in integrin-fibronectin binding become obscured in the ligand-occupied state. Because the epitopes of some function-blocking anti-integrin monoclonal antibodies (mAbs) lie near the ligand-binding pocket, it follows that the epitopes of these mAbs may become shielded in the ligand-occupied state. Here, we tested whether function-blocking mAbs directed against α5β1 can interact with the integrin after it forms a complex with an RGD-containing fragment of fibronectin. We showed that the anti-α5 subunit mAbs JBS5, SNAKA52, 16, and P1D6 failed to disrupt IFCs and hence appeared unable to bind to the ligand-occupied state. In contrast, the allosteric anti-β1 subunit mAbs 13, 4B4, and AIIB2 could dissociate IFCs and therefore were able to interact with the ligand-bound state. However, another class of function-blocking anti-β1 mAbs, exemplified by Lia1/2, could not disrupt IFCs. This second class of mAbs was also distinguished from 13, 4B4, and AIIB2 by their ability to induce homotypic cell aggregation. Although the epitope of Lia1/2 was closely overlapping with those of 13, 4B4, and AIIB2, it appeared to lie closer to the ligand-binding pocket. A new model of the α5β1-fibronectin complex supports our hypothesis that the epitopes of mAbs that fail to bind to the ligand-occupied state lie within, or very close to, the integrin-fibronectin interface. Importantly, our findings imply that the efficacy of some therapeutic anti-integrin mAbs could be limited by epitope masking. PMID:27484800

  19. 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.

  20. Filter penetration and breathing resistance evaluation of respirators and dust masks.

    PubMed

    Ramirez, Joel; O'Shaughnessy, Patrick

    2017-02-01

    The primary objective of this study was to compare the filter performance of a representative selection of uncertified dust masks relative to the filter performance of a set of NIOSH-approved N95 filtering face-piece respirators (FFRs). Five different models of commercially available dust masks were selected for this study. Filter penetration of new dust masks was evaluated against a sodium chloride aerosol. Breathing resistance (BR) of new dust masks and FFRs was then measured for 120 min while challenging the dust masks and FFRs with Arizona road dust (ARD) at 25°C and 30% relative humidity. Results demonstrated that a wide range of maximum filter penetration was observed among the dust masks tested in this study (3-75% at the most penetrating particle size (p < 0.001). The breathing resistances of the unused FFRs and dust masks did not vary greatly (8-13 mm H2O) but were significantly different (p < 0.001). After dust loading there was a significant difference between the BR caused by the ARD dust layer on each FFR and dust mask. Microscopic analysis of the external layer of each dust mask and FFR suggests that different collection media in the external layer influences the development of the dust layer and therefore affects the increase in BR differently between the tested models. Two of the dust masks had penetration values < 5% and quality factors (0.26 and 0.33) comparable to those obtained for the two FFRs (0.23 and 0.31). However, the remaining three dust masks, those with penetration > 15%, had quality factors ranging between 0.04-0.15 primarily because their initial BR remained relatively high. These results indicate that some dust masks analysed during this research did not have an expected very low BR to compensate for their high penetration.

  1. Improving vision by pupil masking

    PubMed Central

    Bonaque-González, Sergio; Ríos-Rodríguez, Susana; López-Gil, Norberto

    2016-01-01

    We propose an alternative solution to improve visual quality by spatially modulating the amplitude of light passing into the eye (related to the eye's transmittance), in contrast to traditional correction of the wavefront phase (related to the local refractive power). Numerical simulations show that masking the aberrated areas at the pupil plane should enhance visual function, especially in highly aberrated eyes. This correction could be implemented in practice using customized contact or intraocular lenses. PMID:27446688

  2. Application of CPL mask for whole chip 65nm DRAM patterning

    NASA Astrophysics Data System (ADS)

    Lin, Orson; Hung, Richard; Lee, Booky; Wu, Yuan-Hsun; Kozuma, Makoto; Shih, Chiang-Lin; Lin, Jengping; Hsu, Michael; Hsu, Stephen D.

    2005-06-01

    To extend the application of ArF exposure tool, CPL is one of the most powerful technologies for the resolution enhancement. From previous study, the 2nd level writing by E-Beam writer has been developed to ensure the manufacturability of CPL process. To fulfill the application of CPL Mask, we implemented this technology for 65nm DRAM patterning. First we studied the performance and characteristics of CPL mask with optimized exposure illumination setting for the desired pattern and dimension of 65nm DRAM. Then the mask data for CPL mask manufacture has been generated by modeled pattern decomposition approach together with rule and modeled OPC. This was accomplished by using an engine named MaskWeaver. For the manufacture of CPL mask, we used a binary mask and the Qz was etched for the 180 degrees phase difference. We utilized a 2nd level writing by an E-Beam writer to make the zebra pattern that was generated by the engine for the optimized patterning performance. The exposure tool we utilized for the verification of wafer patterning is an advanced 193nm exposure system. The process performance indexes such as MEEF, process window, CD uniformity were collected to show the capability of CPL process. Also, simulation and empirical data were compared to verify the performance of CPL technology. So by using an optimized CPL technology included mask data generation skill, mask making specifications, and ArF illumination optimization, we can meet the manufacture requirement of 65nm DRAM.

  3. Combining mask and OPC process verification for improved wafer patterning and yield

    NASA Astrophysics Data System (ADS)

    Hamouda, Ayman; Abdelghany, Hesham

    2016-10-01

    As technology advances into deep submicron nodes, the mask manufacturing process accuracy become more important. Mask Process Correction (MPC) has been transitioning from Rules-Based Mask Process correction to Model-Based Mask Process Correction mode. MPC is a subsequent step to OPC, where additional perturbation is applied to the mask shapes to correct for the mask manufacturing process. Shifting towards full model-based MPC is driven mainly by the accuracy requirements in advanced technology nodes, both for DUV and EUV processes. In the current state-of-the-art MPC process, MPC is completely decoupled from OPC, where each of them assumes that the other is executing perfectly. However, this decoupling is not suitable anymore due to the limited tolerance in the mask CDU budget and the increased wafer CDU requirements required from OPC. It is becoming more important to reduce any systematic mask errors, especially where they matter the most. In this work, we present a new combined-verification methodology that allows testing the combined effect of mask process and lithography process together and judging the final wafer patterning quality. This has the potential to intercept risks due to superposition of OPC and MPC correction residual errors, and capturing and correcting such a previously hidden source of patterning degradation.

  4. 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.

  5. Shadows alter facial expressions of Noh masks.

    PubMed

    Kawai, Nobuyuki; Miyata, Hiromitsu; Nishimura, Ritsuko; Okanoya, Kazuo

    2013-01-01

    A Noh mask, worn by expert actors during performance on the Japanese traditional Noh drama, conveys various emotional expressions despite its fixed physical properties. How does the mask change its expressions? Shadows change subtly during the actual Noh drama, which plays a key role in creating elusive artistic enchantment. We here describe evidence from two experiments regarding how attached shadows of the Noh masks influence the observers' recognition of the emotional expressions. In Experiment 1, neutral-faced Noh masks having the attached shadows of the happy/sad masks were recognized as bearing happy/sad expressions, respectively. This was true for all four types of masks each of which represented a character differing in sex and age, even though the original characteristics of the masks also greatly influenced the evaluation of emotions. Experiment 2 further revealed that frontal Noh mask images having shadows of upward/downward tilted masks were evaluated as sad/happy, respectively. This was consistent with outcomes from preceding studies using actually tilted Noh mask images. Results from the two experiments concur that purely manipulating attached shadows of the different types of Noh masks significantly alters the emotion recognition. These findings go in line with the mysterious facial expressions observed in Western paintings, such as the elusive qualities of Mona Lisa's smile. They also agree with the aesthetic principle of Japanese traditional art "yugen (profound grace and subtlety)", which highly appreciates subtle emotional expressions in the darkness.

  6. Inverted hemispherical mask colloidal lithography.

    PubMed

    Xu, Haixia; Rao, Wenyuan; Meng, Jun; Shen, Yang; Jin, Chongjun; Wang, Xuehua

    2009-11-18

    This paper presents a cost-effective nanofabrication method for forming large area and high coverage two-dimensional metal nanostructures on flat and curved surfaces. This method starts with a periodic array of hemispherical dimples on polystyrene (PS) film prepared by colloidal lithography with a sacrificial layer of polyacrylic acid (PAA) underneath. After the removal of PAA in water solution, the PS layer is turned over and attached to the substrate to be patterned. An inverted hemispherical mask is formed after oxygen plasma etching. As the holes at the bottom are much larger than those on the surface, the mask is especially suitable for a standard lift-off process. Based on this mask, metal nano-disk and pair-disk arrays, as well as two-dimensional nanostructures on a curved surface, have been fabricated. Optical measurement shows that a surface plasmon resonance exists in a periodic disk array. This method is valuable for the fabrication of a magnifying metamaterial hyperlens in order to eliminate the limitation of optical diffraction.

  7. Spatial release from informational masking

    NASA Astrophysics Data System (ADS)

    Rakerd, Brad; Aaronson, Neil L.

    2001-05-01

    A new method for investigating spatial release from informational masking was developed and employed in two experiments. The new method is computer controlled and efficient. It employs the versatile coordinate response measure speech stimulus set [Bolia et al., J. Acoust. Soc. Am. 107, 1065 (2000)]. The experiments were conducted in an anechoic room, with a primary loudspeaker in front of the listener and a secondary loudspeaker at 60 deg to the right. Target messages were presented from the primary speaker only. For a standard, distractor messages, simultaneous with the target, were also presented from the primary speaker only. Spatial release was measured by presenting the distractors from both primary and secondary speakers with a temporal offset. Experiment 1 fixed the offset (secondary leading, +4 ms) and varied the number of distractors (1 to 3) and the target-to-distractor ratio (-12 to +4 dB). Masking release, sometimes as large as 10 dB, was found for all combinations of these variables. Experiment 2 varied the offset over a wide range of values. Substantial release from masking was found for both positive and negative offsets, but only in the range in which speech echoes are suppressed (<50 ms). [Work supported by NIDCD grant DC 00181.

  8. [A multicenter, double-masked, randomized evaluation of olopatadine 0.2% using the conjunctival allergen challenge model in Japanese patients with allergic conjunctivitis].

    PubMed

    Ohno, Shigeaki

    2012-12-01

    Olopatadine hydrochloride ophthalmic solution, 0.2% (olopatadine 0.2%) is approved for allergic conjunctivitis when instilled twice-daily. The objective of this study was to evaluate the efficacy and safety of olopatadine 0.2% (instilled twice-daily) versus vehicle and olopatadine 0.1% (instilled 4-times daily) in Japanese patients with allergic conjunctivitis. A multicenter, parallel-group, double-masked, randomized, conjunctival allergen challenge (CAC) study. Patients > or = 18 years of age with histories of allergic conjunctivitis were treated with either olopatadine 0.2% or olopatadine 0.1% in a single eye and the vehicle in the contralateral eye at 1 visit. Overall, 267 patients were enrolled. Olopatadine 0.2% was superior to its vehicle for ocular itching (p < 0.0001 at the time of observation) and marginally superior for total redness (p = 0.0543 at the time of observation). Olopatadine 0.2% was similar to olopatadine 0.1% for ocular itching at the time of observation. No trends were identified through a review of safety parameters. Olopatadine 0.2% (instilled twice-daily) is safe, well tolerated, superior to the vehicle, and similar to olopatadine 0.1% in preventing ocular itching. Olopatadine 0.2%, which can be instilled less often than olopatadine 0.1%, is a useful new option for allergic conjunctivitis in Japanese patients that could potentially result in better treatment compliance.

  9. Comparison of Aerosol Delivery by Face Mask and Tracheostomy Collar.

    PubMed

    Bugis, Alaa A; Sheard, Meryl M; Fink, James B; Harwood, Robert J; Ari, Arzu

    2015-09-01

    The purpose of this study was to compare the performance of a tracheostomy collar, Wright mask, and aerosol mask attached to a jet nebulizer in facilitating aerosolized medication delivery to the lungs. We also compared albuterol delivery with open versus closed fenestration and determined the effect of inspiratory-expiratory ratio (I:E) on aerosol delivery. Albuterol (2.5 mg/3 mL) was administered to an in vitro model consisting of an adult teaching mannequin extrathoracic and upper airway with stoma intubated with an 8-mm fenestrated tracheostomy tube. The cuff was deflated. A collecting filter at the level of the bronchi was connected to a breathing simulator at a tidal volume of 400 mL, breathing frequency of 20 breaths/min, and I:E of 2:1 and 1:2. A jet nebulizer was operated with O2 at 8 L/min. Each interface was tested in triplicate. The flow was discontinued at the end of nebulization. For each test, the nebulizer was attached to a tracheostomy collar with the fenestration open or closed, a Wright mask, or an aerosol mask. Drug was analyzed by spectrophotometry (276 nm). A paired t test and analysis of variance were performed (P < .05). The mean ± SD percent albuterol dose delivered distal to the bronchi was greater with the tracheostomy collar with a closed fenestration (9.4 ± 1.5%) compared with an open fenestration (7.0 ± 0.8%). The doses delivered with the Wright mask (4.1 ± 0.6%) and aerosol mask (3.5 ± 0.04%) were both less than with the tracheostomy collar under either condition (P < .05). Increasing the I:E from 1:2 to 2:1 increased aerosol delivery by 2.5-4%, with significance for the tracheostomy collar with an open fenestration (11.6 ± 1.4%), Wright mask (7.2 ± 0.6%), and aerosol mask (6.1 ± 0.5%). In an adult tracheostomy model, the tracheostomy collar delivered more aerosol to the bronchi than the Wright or aerosol mask. An I:E of 2:1 caused greater aerosol deposition compared with an I:E of 1:2. During aerosol administration via a

  10. Fabrication and commercialization of scalpel masks

    NASA Astrophysics Data System (ADS)

    Novembre, Anthony E.; Peabody, Milton L., Jr.; Blakey, Myrtle I.; Farrow, Reginald C.; Kasica, Richard J.; Liddle, James A.; Saunders, Thomas E.; Tennant, Donald M.

    1998-09-01

    SCALPEL masks have been fabricated for use in the Proof-of- Lithography system and to demonstrate the feasibility of having them produced by a commercial blank manufacturer and optical mask shops. Masks blanks are formed from 100 mm diameter silicon wafers. A 100-150 nm thick SiNx layer is LPCVD deposited onto the wafers followed by magnetron sputter deposition of a thin Cr/W metal layer which is used as the scatterer layer for the mask>the mask is supported by an underlying network of struts which are arranged to be compatible with the step and scan writing strategy of the exposure tool and to provide robustness to the mask. Crystallographic wet etching of the silicon wafer forms membranes and struts. To date over 300 mask blanks have been formed and yield data as a function of the thickness of the silicon nitride membrane has been quantified. Recent developments in the mask blank formation process include the production of blanks by MCNC who serve as a commercial source of SCALPEL mask blanks. They have successfully delivered 36 blanks that exhibit equivalent properties to those produced at Lucent. Mask patterning has been performed at the commercial optical mask shops of PHOTRONICS and DUPONT. In this investigation a MEBES exposure system has been used to write patterns. The resist used is ZEP-520 and development and pattern transfer processes are performed in the STEAG-Hammatech spray/spin processing tool. Metrology is performed using a KMS 310 RT optical microscope. Pattern placement accuracy is measured on the LMS 2020 system without modification. The masks are inspected for defects using the optical based KLA 300 series inspection system in a die to die mode and in transmission. Results to date suggest feasibility of producing SCALPEL masks by a commercial blank supplier and by merchant optical mask shops.

  11. A novel method to quantify the complex mask patterns

    NASA Astrophysics Data System (ADS)

    Tung, Yu-Lung; Sun, Che-Yuan; Chuang, Shu-Chuan; Luo, Woei-Bin; Hu, Jia-Rui; Chen, Hsiang-Lin; Lin, Hua-Tai; Ke, Chih-Ming; Gau, Tsai-Sheng

    2016-03-01

    Immersion technology has successfully extends the application of ArF lithography in the semiconductor. However, as we further push the k1 factor below 0.3, the patterning fidelities degrade significantly. In this paper, a novel method to quantify the mask fidelity of complex 2D patterns is proposed. With this method, the critical dimension (CD) error of both edge placement error (EPE) and corner rounding can be well described by using 2 indices "bias" and "blur" respectively. The "bias" is defined as the CD offset between the mask and the targets, and the "blur" is a derived term that can well represent the mask rounding. These 2 indices are not only able to describe the mask quality but also able to link with model parameters that are used in optical proximity correction (OPC) and some other applications. In this paper, we demonstrate the methodology and quantify the actual mask quality on the complex and critical 2D patterning in the advanced nodes.

  12. Masked priming effect reflects evidence accumulated by the prime.

    PubMed

    Kinoshita, Sachiko; Norris, Dennis

    2010-01-01

    In the same-different match task, masked priming is observed with the same responses but not different responses. Norris and Kinoshita's (2008) Bayesian reader account of masked priming explains this pattern based on the same principle as that explaining the absence of priming for nonwords in the lexical decision task. The pattern of priming follows from the way the model makes optimal decisions in the two tasks; priming does not depend on first activating the prime and then the target. An alternative explanation is in terms of a bias towards responding "same" that exactly counters the facilitatory effect of lexical access. The present study tested these two views by varying both the degree to which the prime predicts the response and the visibility of the prime. Unmasked primes produced effects expected from the view that priming is influenced by the degree to which the prime predicts the response. In contrast, with masked primes, the size of priming for the same response was completely unaffected by predictability. These results rule out response bias as an explanation of the absence of masked priming for different responses and, in turn, indicate that masked priming is not a consequence of automatic lexical access of the prime.

  13. Facial skin beautification using adaptive region-aware masks.

    PubMed

    Liang, Lingyu; Jin, Lianwen; Li, Xuelong

    2014-12-01

    In this paper, we propose a unified facial beautification framework with respect to skin homogeneity, lighting, and color. A novel region-aware mask is constructed for skin manipulation, which can automatically select the edited regions with great precision. Inspired by the state-of-the-art edit propagation techniques, we present an adaptive edge-preserving energy minimization model with a spatially variant parameter and a high-dimensional guided feature space for mask generation. Using region-aware masks, our method facilitates more flexible and accurate facial skin enhancement while the complex manipulations are simplified considerably. In our beautification framework, a portrait is decomposed into smoothness, lighting, and color layers by an edge-preserving operator. Next, facial landmarks and significant features are extracted as input constraints for mask generation. After three region-aware masks have been obtained, a user can perform facial beautification simply by adjusting the skin parameters. Furthermore, the combinations of parameters can be optimized automatically, depending on the data priors and psychological knowledge. We performed both qualitative and quantitative evaluation for our method using faces with different genders, races, ages, poses, and backgrounds from various databases. The experimental results demonstrate that our technique is superior to previous methods and comparable to commercial systems, for example, PicTreat, Portrait+ , and Portraiture.

  14. Economics of automation for the design-to-mask interface

    NASA Astrophysics Data System (ADS)

    Erck, Wesley

    2009-04-01

    Mask order automation has increased steadily over the years through a variety of individual mask customer implementations. These have been supported by customer-specific software at the mask suppliers to support the variety of customer output formats. Some customers use the SEMI P10 1 standard, some use supplier-specific formats, and some use customer-specific formats. Some customers use little automation and depend instead on close customer-supplier relationships. Implementations are varied in quality and effectiveness. A major factor which has prolonged the adoption of more advanced and effective solutions has been a lack of understanding of the economic benefits. Some customers think standardized automation mainly benefits the mask supplier in order entry automation, but this ignores a number of other significant benefits which differ dramatically for each party in the supply chain. This paper discusses the nature of those differing advantages and presents simple models suited to four business cases: integrated device manufacturers (IDM), fabless companies, foundries and mask suppliers. Examples and estimates of the financial advantages for these business types will be shown.

  15. Auditory Time-Frequency Masking for Spectrally and Temporally Maximally-Compact Stimuli

    PubMed Central

    Laback, Bernhard; Savel, Sophie; Ystad, Sølvi; Balazs, Peter; Meunier, Sabine; Kronland-Martinet, Richard

    2016-01-01

    Many audio applications perform perception-based time-frequency (TF) analysis by decomposing sounds into a set of functions with good TF localization (i.e. with a small essential support in the TF domain) using TF transforms and applying psychoacoustic models of auditory masking to the transform coefficients. To accurately predict masking interactions between coefficients, the TF properties of the model should match those of the transform. This involves having masking data for stimuli with good TF localization. However, little is known about TF masking for mathematically well-localized signals. Most existing masking studies used stimuli that are broad in time and/or frequency and few studies involved TF conditions. Consequently, the present study had two goals. The first was to collect TF masking data for well-localized stimuli in humans. Masker and target were 10-ms Gaussian-shaped sinusoids with a bandwidth of approximately one critical band. The overall pattern of results is qualitatively similar to existing data for long maskers. To facilitate implementation in audio processing algorithms, a dataset provides the measured TF masking function. The second goal was to assess the potential effect of auditory efferents on TF masking using a modeling approach. The temporal window model of masking was used to predict present and existing data in two configurations: (1) with standard model parameters (i.e. without efferents), (2) with cochlear gain reduction to simulate the activation of efferents. The ability of the model to predict the present data was quite good with the standard configuration but highly degraded with gain reduction. Conversely, the ability of the model to predict existing data for long maskers was better with than without gain reduction. Overall, the model predictions suggest that TF masking can be affected by efferent (or other) effects that reduce cochlear gain. Such effects were avoided in the experiment of this study by using maximally

  16. High performance mask fabrication process for the next-generation mask production

    NASA Astrophysics Data System (ADS)

    Yagawa, Keisuke; Ugajin, Kunihiro; Suenaga, Machiko; Kobayashi, Yoshihito; Motokawa, Takeharu; Hagihara, Kazuki; Saito, Masato; Itoh, Masamitsu

    2014-07-01

    ArF immersion lithography combined with double patterning has been used for fabricating below half pitch 40nm devices. However, when pattern size shrinks below 20nm, we must use new technology like quadruple patterning process or next generation lithography (NGL) solutions. Moreover, with change in lithography tool, next generation mask production will be needed. According to ITRS 2013, fabrication of finer patterns less than 15nm will be required on mask plate in NGL mask production 5 years later [1]. In order to fabricate finer patterns on mask, higher resolution EB mask writer and high performance fabrication process will be required. In a previous study, we investigated a potential of mask fabrication process for finer patterning and achieved 17nm dense line pattern on mask plate by using VSB (Variable Shaped Beam) type EB mask writer and chemically amplified resist [2][3]. After a further investigation, we constructed higher performance mask process by using new EB mask writer EBM9000. EBM9000 is the equipment supporting hp16nm generation's photomask production and has high accuracy and high throughput. As a result, we achieved 15.5nm pattern on mask with high productivity. Moreover, from evaluation of isolated pattern, we proved that current mask process has the capability for sub-10nm pattern. These results show that the performance of current mask fabrication process have the potential to fabricate the next-generation mask.

  17. Early, Equivalent ERP Masked Priming Effects for Regular and Irregular Morphology

    ERIC Educational Resources Information Center

    Morris, Joanna; Stockall, Linnaea

    2012-01-01

    Converging evidence from behavioral masked priming (Rastle & Davis, 2008), EEG masked priming (Morris, Frank, Grainger, & Holcomb, 2007) and single word MEG (Zweig & Pylkkanen, 2008) experiments has provided robust support for a model of lexical processing which includes an early, automatic, visual word form based stage of morphological parsing…

  18. Early, Equivalent ERP Masked Priming Effects for Regular and Irregular Morphology

    ERIC Educational Resources Information Center

    Morris, Joanna; Stockall, Linnaea

    2012-01-01

    Converging evidence from behavioral masked priming (Rastle & Davis, 2008), EEG masked priming (Morris, Frank, Grainger, & Holcomb, 2007) and single word MEG (Zweig & Pylkkanen, 2008) experiments has provided robust support for a model of lexical processing which includes an early, automatic, visual word form based stage of morphological parsing…

  19. BAYESIAN INSIGHTS ON DISCLOSURE LIMITATION: MASK OR IMPUTE?

    SciTech Connect

    S. KELLER-MCNULTY; G. DUNCAN

    2000-10-01

    Statistical agencies seek to disseminate useful data while keeping low the risk of statistical confidentiality disclosure. Recognizing that reidentification of data is generally inadequate to protect its confidentiality against attack by a data snooper, agencies restrict the data they release for general use. Typically, these restricted data procedures have involved transformation or masking of the original, collected data through such devices as adding noise, topcoding, data swapping, and recoding. Recently, proposals have been put forth for the release of synthetic data, simulated from models constructed from the original data. This paper gives a framework for the comparison of masking and synthetic data as two approaches to disclosure limitation. Particular attention is paid to data utility and disclosure risk. Examples of instantiation of masking and of synthetic data construction are provided to illustrate the concepts. Particular attention is paid to data swapping. Insights drawn from the Bayesian paxadigm are provided.

  20. Taste masked thin films printed by jet dispensing.

    PubMed

    Scoutaris, Nikolaos; Snowden, Martin; Douroumis, Dennis

    2015-10-30

    Taste masking of bitter active substances is an emerging area in the pharmaceutical industry especially for paediatric/geriatric medications. In this study we introduce the use of jet dispensing as a taste masking technology by printing mucosal thin films of three model bitter substances, Cetirizine HCl, Diphenylhydramine HCl and Ibuprofen. The process was used to dispense aqueous drugs/polymer solutions at very high speed where eventually the drugs were embedded in the polymer matrix. The in vivo evaluation of jet-dispensed mucosal films showed excellent taste masking for drug loadings from 20 to 40%. Jet dispensing was proved to make uniform, accurate and reproducible thin films with excellent content uniformity. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. "Perplex't paths": youth and authority in Milton's Mask.

    PubMed

    Greteman, Blaine

    2009-01-01

    This essay argues that John Milton's "A Mask Presented at Ludlow Castle" (1634) is influenced by early modern concepts of childhood in a way that critics have not recognized. Childhood was a problematic concept in contemporary religious, pedagogical, and legal discourses. Children were depicted as models of submission, but prone to impetuous indiscretion, and their path to adult agency was strewn with pitfalls, especially in the liminal period of youth. "A Mask" engages with and transforms these discourses. It rejects the political quietism routinely associated with childhood and shows that the child's unique sensitivity may offer a route to a particularly powerful kind of voice.

  2. Mask roughness and its implications for LER at the 22- and 16-nm nodes

    SciTech Connect

    Naulleau, Patrick; George, Simi A.; McClinton, Brittany M.

    2010-02-16

    Line-edge roughness (LER) remains the most significant challenge facing the development of extreme ultraviolet (EUV) resist. The mask, however, has been found to be a significant contributor to image-plane LER. This has long been expected based on modeling and has more recently been demonstrated experimentally. Problems arise from both mask-absorber LER as well as mask multilayer roughness leading to random phase variations in the reflected beam and consequently speckle. Understanding the implications this has on mask requirements for the 22-nm half pitch node and below is crucial. Modeling results indicate a replicated surface roughness (RSR) specification of 50 pm and a ruthenium capping layer roughness specification of 440 pm. Moreover, modeling indicates that it is crucial to achieve the current ITRS specifications for mask absorber LER which is significantly smaller than current capabilities.

  3. Mask data volume: explosion or damp squib?

    NASA Astrophysics Data System (ADS)

    Spence, Chris; Goad, Scott; Buck, Peter; Gladhill, Richard; Cinque, Russell

    2005-11-01

    Mask data file sizes are increasing as we move from technology generation to generation. The historical 30% linear shrink every 2-3 years that has been called Moore's Law, has driven a doubling of the transistor budget and hence feature count. The transition from steppers to step-and-scan tools has increased the area of the mask that needs to be patterned. At the 130nm node and below, Optical Proximity Correction (OPC) has become prevalent, and the edge fragmentation required to implement OPC leads to an increase in the number of polygons required to define the layout. Furthermore, Resolution Enhancement Techniques (RETs) such as Sub-Resolution Assist Features (SRAFs) or tri-tone Phase Shift Masks (PSM) require additional features to be defined on the mask which do not resolve on the wafer, further increasing masks volumes. In this paper we review historical data on mask file sizes for microprocessor designs. We consider the consequences of this increase in file size on Mask Data Prep (MDP) activities, both within the Integrated Device Manufacturer (IDM) and Mask Shop, namely: computer resources, storage and networks (for file transfer). The impact of larger file sizes on mask writing times is also reviewed. Finally we consider, based on the trends that have been observed over the last 5 technology nodes, what will be required to maintain reasonable MDP and mask manufacturing cycle times.

  4. Evidence for Early Morphological Decomposition: Combining Masked Priming with Magnetoencephalography

    ERIC Educational Resources Information Center

    Lehtonen, Minna; Monahan, Philip J.; Poeppel, David

    2011-01-01

    Are words stored as morphologically structured representations? If so, when during word recognition are morphological pieces accessed? Recent masked priming studies support models that assume early decomposition of (potentially) morphologically complex words. The electrophysiological evidence, however, is inconsistent. We combined masked…

  5. Evidence for Early Morphological Decomposition: Combining Masked Priming with Magnetoencephalography

    ERIC Educational Resources Information Center

    Lehtonen, Minna; Monahan, Philip J.; Poeppel, David

    2011-01-01

    Are words stored as morphologically structured representations? If so, when during word recognition are morphological pieces accessed? Recent masked priming studies support models that assume early decomposition of (potentially) morphologically complex words. The electrophysiological evidence, however, is inconsistent. We combined masked…

  6. Masked Inhibitory Priming in English: Evidence for Lexical Inhibition

    ERIC Educational Resources Information Center

    Davis, Colin J.; Lupker, Stephen J.

    2006-01-01

    Predictions derived from the interactive activation (IA) model were tested in 3 experiments using the masked priming technique in the lexical decision task. Experiment 1 showed a strong effect of prime lexicality: Classifications of target words were facilitated by orthographically related nonword primes (relative to unrelated nonword primes) but…

  7. High altitude hypoxia, a mask and a Street. Donation of an aviation BLB oxygen mask apparatus from World War 2.

    PubMed

    Cooper, M G; Street, N E

    2017-03-01

    The history of hypoxia prevention is closely inter-related with high altitude mountain and aviation physiology. One pioneering attempt to overcome low inspired oxygen partial pressures in aviation was the BLB mask-named after the three designers-Walter M Boothby, W Randolph Lovelace II and Arthur H Bulbulian. This mask and its variations originated just prior to World War 2 when aircraft were able to fly higher than 10,000 feet and pilot hypoxia affecting performance was an increasing problem. We give a brief description of the mask and its designers and discuss the donation of a model used by the British War Office in October 1940 and donated to the Harry Daly Museum at the Australian Society of Anaesthetists by the family of Dr Fred Street. Dr Street was a pioneering paediatric surgeon in Australia and served as a doctor in the Middle East and New Guinea in World War 2. He received the Military Cross.

  8. Orthogonal subspaces for correlation masking

    NASA Technical Reports Server (NTRS)

    Juday, Richard D.; Fisher, Timothy E.

    1990-01-01

    A digital correlation mask that induces orthogonality among a prescribed set of reference imagery is described. In this particular implementation, the resulting correlation is undersampled and shift-variant, though if it is applied to optical correlators, those limitations are removed. A method of introducing orthogonality among the weights among the training set from which filter values are obtained is derived, so that the correlation value from a given filter is representative of the unique nature of the reference object as compared against the other objects in the training class.

  9. Repairing native defects on EUV mask blanks

    NASA Astrophysics Data System (ADS)

    Lawliss, Mark; Gallagher, Emily; Hibbs, Michael; Seki, Kazunori; Isogawa, Takeshi; Robinson, Tod; LeClaire, Jeff

    2014-10-01

    Mask defectivity is a serious problem for all lithographic masks, but especially for EUV masks. Defects in the EUV blank are particularly challenging because their elimination is beyond control of the mask fab. If defects have been identified on a mask blank, patterns can be shifted to place as many blank defects as possible in regions where printing impact will be eliminated or become unimportant. For those defects that cannot be mitigated through pattern shift, repair strategies must be developed. Repairing defects that occur naturally in the EUV blank is challenging because the printability of these defects varies widely. This paper describes some types of native defects commonly found and begins to outline a triage strategy for defects that are identified on the blank. Sample defects best suited to nanomachining repair are treated in detail: repairs are attempted, characterized using mask metrology and then tested for printability. Based on the initial results, the viability of repairing EUV blank native defects is discussed.

  10. Helical apodizers for tunable hyper Gaussian masks

    NASA Astrophysics Data System (ADS)

    Ojeda-Castañeda, J.; Ledesma, Sergio; Gómez-Sarabia, Cristina M.

    2013-09-01

    We discuss an optical method for controlling the half-width of Gaussian like transmittance windows, by using a pair of absorption masks that have both radial and helical amplitude variations. For describing the radial part of the proposed masks, we employ amplitude transmittance profiles of the form T(ρ) = exp(- ρ s ). For s = 2, one has an amplitude transmittance that is proportional to a Gaussian function. A sub Gaussian mask is defined by a value of s < 2. And if s > 2, one has super Gaussian masks. Our discussion considers that any of these radially varying masks has also helical modulations. We show that by using a suitable pair of this type of masks, one can control the halfwidth of Gaussian like windows.

  11. Polyurethane Masks Large Areas in Electroplating

    NASA Technical Reports Server (NTRS)

    Beasley, J. L.

    1985-01-01

    Polyurethane foam provides effective mask in electroplating of copper or nickel. Thin layer of Turco maskant painted on area to be masked: Layer ensures polyurethane foam removed easily after served its purpose. Component A, isocyanate, and component B, polyol, mixed together and brushed or sprayed on mask area. Mixture reacts, yielding polyurethane foam. Foam prevents deposition of nickel or copper on covered area. New method saves time, increases productivity and uses less material than older procedures.

  12. Influence of Planck foreground masks in the large angular scale quadrant CMB asymmetry

    NASA Astrophysics Data System (ADS)

    Santos, L.; Cabella, P.; Villela, T.; Zhao, W.

    2015-12-01

    Context. The measured cosmic microwave background (CMB) angular distribution shows high consistency with the ΛCDM model, which predicts cosmological isotropy as one of its fundamental characteristics. However, isotropy violations were reported in CMB temperature maps of the Wilkinson Microwave Anisotropy Probe (WMAP) and confirmed by Planck satellite data. Aims: Our purpose is to investigate the influence of different sky cuts (masks) employed in the analysis of CMB angular distribution, in particular in the excess of power in the southeastern quadrant (SEQ) and the lack of power in the northeastern quadrant (NEQ), found in both WMAP and Planck data. Methods: We compared the two-point correlation function (TPCF) computed for each quadrant of the CMB foreground-cleaned temperature maps to 1000 Monte Carlo (MC) simulations generated assuming the ΛCDM best-fit power spectrum using four different masks, from the least to the most severe one: mask-rulerminimal, UT78, U73, and U66. In addition to the quadrants and for a better understanding of these anomalies, we computed the TPCF using the mask-rulerminimal for circular regions in the map where the excess and lack of power are present. We also compared, for completeness, the effect of Galactic cuts (+/-10, 20, 25, and 30 degrees above/below the Galactic plane) in the TPCF calculations as compared to the MC simulations. Results: We found consistent results for three masks, namely mask-rulerminimal, U73, and U66. The results indicate that the excess of power in the SEQ tends to vanish as the portion of the sky covered by the mask increases and the lack of power in the NEQ remains virtually unchanged. A different result arises for the newly released UT78 Planck mask. When this mask is applied, the NEQ is no longer anomalous. On the other hand, the excess of power in the SEQ becomes the most significant one among the masks. Nevertheless, the asymmetry between the SEQ and NEQ is independent of the mask and it disagrees

  13. Serotonin dependent masking of hippocampal sharp wave ripples.

    PubMed

    ul Haq, Rizwan; Anderson, Marlene L; Hollnagel, Jan-Oliver; Worschech, Franziska; Sherkheli, Muhammad Azahr; Behrens, Christoph J; Heinemann, Uwe

    2016-02-01

    Sharp wave ripples (SPW-Rs) are thought to play an important role in memory consolidation. By rapid replay of previously stored information during slow wave sleep and consummatory behavior, they result from the formation of neural ensembles during a learning period. Serotonin (5-HT), suggested to be able to modify SPW-Rs, can affect many neurons simultaneously by volume transmission and alter network functions in an orchestrated fashion. In acute slices from dorsal hippocampus, SPW-Rs can be induced by repeated high frequency stimulation that induces long-lasting LTP. We used this model to study SPW-R appearance and modulation by 5-HT. Although stimulation in presence of 5-HT permitted LTP induction, SPW-Rs were "masked"--but appeared after 5-HT wash-out. This SPW-R masking was dose dependent with 100 nM 5-HT being sufficient--if the 5-HT re-uptake inhibitor citalopram was present. Fenfluramine, a serotonin releaser, could also mask SPW-Rs. Masking was due to 5-HT1A and 5-HT2A/C receptor activation. Neither membrane potential nor membrane conductance changes in pyramidal cells caused SPW-R blockade since both remained unaffected by combining 5-HT and citalopram. Moreover, 10 and 30 μM 5-HT mediated SPW-R masking preceded neuronal hyperpolarization and involved reduced presynaptic transmitter release. 5-HT, as well as a 5-HT1A agonist, augmented paired pulse facilitation and affected the coefficient of variance. Spontaneous SPW-Rs in mice hippocampal slices were also masked by 5-HT and fenfluramine. While neuronal ensembles can acquire long lasting LTP during higher 5-HT levels, lower 5-HT levels enable neural ensembles to replay previously stored information and thereby permit memory consolidation memory.

  14. Terahertz coded aperture mask using vanadium dioxide bowtie antenna array

    NASA Astrophysics Data System (ADS)

    Nadri, Souheil; Percy, Rebecca; Kittiwatanakul, Lin; Arsenovic, Alex; Lu, Jiwei; Wolf, Stu; Weikle, Robert M.

    2014-09-01

    Terahertz imaging systems have received substantial attention from the scientific community for their use in astronomy, spectroscopy, plasma diagnostics and security. One approach to designing such systems is to use focal plane arrays. Although the principle of these systems is straightforward, realizing practical architectures has proven deceptively difficult. A different approach to imaging consists of spatially encoding the incoming flux of electromagnetic energy prior to detection using a reconfigurable mask. This technique is referred to as "coded aperture" or "Hadamard" imaging. This paper details the design, fabrication and testing of a prototype coded aperture mask operating at WR-1.5 (500-750 GHz) that uses the switching properties of vanadium dioxide(VO2). The reconfigurable mask consists of bowtie antennas with vanadium dioxide VO2 elements at the feed points. From the symmetry, a unit cell of the array can be represented by an equivalent waveguide whose dimensions limit the maximum operating frequency. In this design, the cutoff frequency of the unit cell is 640 GHz. The VO2 devices are grown using reactive-biased target ion beam deposition. A reflection coefficient (S11) measurement of the mask in the WR-1.5 (500-750 GHz) band is conducted. The results are compared with circuit models and found to be in good agreement. A simulation of the transmission response of the mask is conducted and shows a transmission modulation of up to 28 dB. This project is a first step towards the development of a full coded aperture imaging system operating at WR-1.5 with VO2 as the mask switching element.

  15. Temporal masking of multidimensional tactual stimuli

    NASA Astrophysics Data System (ADS)

    Tan, Hong Z.; Reed, Charlotte M.; Delhorne, Lorraine A.; Durlach, Nathaniel I.; Wan, Natasha

    2003-12-01

    Experiments were performed to examine the temporal masking properties of multidimensional tactual stimulation patterns delivered to the left index finger. The stimuli consisted of fixed-frequency sinusoidal motions in the kinesthetic (2 or 4 Hz), midfrequency (30 Hz), and cutaneous (300 Hz) frequency ranges. Seven stimuli composed of one, two, or three spectral components were constructed at each of two signal durations (125 or 250 ms). Subjects identified target signals under three different masking paradigms: forward masking, backward masking, and sandwiched masking (in which the target is presented between two maskers). Target identification was studied as a function of interstimulus interval (ISI) in the range 0 to 640 ms. For both signal durations, percent-correct scores increased with ISI for each of the three masking paradigms. Scores with forward and backward masking were similar and significantly higher than scores obtained with sandwiched masking. Analyses of error trials revealed that subjects showed a tendency to respond, more often than chance, with the masker, the composite of the masker and target, or the combination of the target and a component of the masker. The current results are compared to those obtained in previous studies of tactual recognition masking with brief cutaneous spatial patterns. The results are also discussed in terms of estimates of information transfer (IT) and IT rate, are compared to previous studies with multidimensional tactual signals, and are related to research on the development of tactual aids for the deaf.

  16. Evaluation of a native vegetation masking technique

    NASA Technical Reports Server (NTRS)

    Kinsler, M. C.

    1984-01-01

    A crop masking technique based on Ashburn's vegetative index (AVI) was used to evaluate native vegetation as an indicator of crop moisture condition. A mask of the range areas (native vegetation) was generated for each of thirteen Great Plains LANDSAT MSS sample segments. These masks were compared to the digitized ground truth and accuracies were computed. An analysis of the types of errors indicates a consistency in errors among the segments. The mask represents a simple quick-look technique for evaluating vegetative cover.

  17. [A new bite block for laryngeal mask].

    PubMed

    Ohe, Y; Ota, M; Tachibana, C; Aoyama, Y

    2001-05-01

    We devised a new bite block made of a used connector of anesthesia machine (ACOMA medical industry CO., LTD.) for laryngeal mask. Fitness for laryngeal mask and strength against patient's biting are the key for its use. Cutting lengthwise the connector (the outside diameter 22 mm, inside diameter 15-19 mm, 55 mm in length) we made a bite block for laryngeal mask. We studied the strength of a new bite block experimentally and recognized its ability to bear the human biting. We conclude a new bite block for laryngeal mask is clinically useful and can be used during anesthesia for its fitness and safety.

  18. X-ray lithography masking

    NASA Technical Reports Server (NTRS)

    Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

    1998-01-01

    X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

  19. Mask lithography for display manufacturing

    NASA Astrophysics Data System (ADS)

    Sandstrom, T.; Ekberg, P.

    2010-05-01

    The last ten years have seen flat displays conquer our briefcases, desktops, and living rooms. There has been an enormous development in production technology, not least in lithography and photomasks. Current masks for large displays are more than 2 m2 and make 4-6 1X prints on glass substrates that are 9 m2. One of the most challenging aspects of photomasks for displays is the so called mura, stripes or blemishes which cause visible defects in the finished display. For the future new and even tighter maskwriter specifications are driven by faster transistors and more complex pixel layouts made necessary by the market's wish for still better image quality, multi-touch panels, 3D TVs, and the next wave of e-book readers. Large OLED screens will pose new challenges. Many new types of displays will be lowcost and use simple lithography, but anything which can show video and high quality photographic images needs a transistor backplane and sophisticated masks for its production.

  20. VIIRS Cloud Mask Validation Exercises

    NASA Astrophysics Data System (ADS)

    Frey, R.; Heidinger, A. K.; Hutchison, K.; Dutcher, S.

    2011-12-01

    The NPP Satellite is scheduled for launch October 25, 2011. Included on the platform is the VIIRS (Visible/Infrared Imager/Suite) instrument which features 16 bands at about 0.75 m spatial resolution and 5 imager bands at roughly 0.375 m resolution. The basic VIIRS cloud mask (VCM) output is a flag that indicates one of four possible cloudy vs. clear conditions for each 0.75 m pixel: confident clear, probably clear, probably cloudy, and confident cloudy. Pre-launch assessment of the VCM algorithm has been performed with use of MODIS observations as proxy input. Several comparisons are shown between VCM results and cloud detection from other instruments and/or algorithms: MODIS cloud mask (MOD35) at the five-minute granule level (L2), global and regional monthly average cloud amounts from MODIS (MOD35) and MODIS-CERES, ISCCP, PATMOS-x (AVHRR), and CALIOP (lidar). In addition to overall results, collocated MODIS observations, CALIOP and VCM cloud determinations are used to evaluate VCM cloud test thresholds and other tunable parameters. The methods shown will be among those used during the Intensive Calibration and Validation period and beyond.

  1. A cluster randomised trial of cloth masks compared with medical masks in healthcare workers

    PubMed Central

    MacIntyre, C Raina; Seale, Holly; Dung, Tham Chi; Hien, Nguyen Tran; Nga, Phan Thi; Chughtai, Abrar Ahmad; Rahman, Bayzidur; Dwyer, Dominic E; Wang, Quanyi

    2015-01-01

    Objective The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). The null hypothesis is that there is no difference between medical masks and cloth masks. Setting 14 secondary-level/tertiary-level hospitals in Hanoi, Vietnam. Participants 1607 hospital HCWs aged ≥18 years working full-time in selected high-risk wards. Intervention Hospital wards were randomised to: medical masks, cloth masks or a control group (usual practice, which included mask wearing). Participants used the mask on every shift for 4 consecutive weeks. Main outcome measure Clinical respiratory illness (CRI), influenza-like illness (ILI) and laboratory-confirmed respiratory virus infection. Results The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%. Conclusions This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated. Trial registration number Australian New Zealand Clinical Trials Registry: ACTRN12610000887077. PMID

  2. 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.

  3. Comparative study of simulations and experiments for contact array patterns on attenuated phase shifting mask

    NASA Astrophysics Data System (ADS)

    Henkel, Thomas; Sczyrba, Martin; Noelscher, Christoph

    2005-11-01

    Experiments and full resist simulations of contact patterns using both infinitely thin masks (2D) and 3-dimensional mask topography (3D) were performed to examine the quality of prediction by simulation. Experimental data were acquired by CD-SEM measurements of contact patterns in resist which were generated using a 193 nm scanner with a numerical aperture of 0.75, circular illumination (σ=0.5), and an attenuated phase shifting mask with 6% transmission. Analysis of the data is performed in terms of dose to size, process window, mask error enhancement factor (MEEF), and printed critical dimension (CD) in resist. Furthermore, an error analysis is performed with respect to mask CD, illumination source, dose and focus error. For the same contact size in resist a parabola like dependence of the mask contact length on contact width was found by experiment and simulation. Fair agreement between 2D and 3D simulation was obtained above 180 nm mask CD whereas a strong difference was observed below this region. Especially the location of the minimum at around 140 nm mask CD can be reasonably described only by 3D simulation. Thus, the prediction of accurate mask biases and process windows in the lower mask CD region is only possible by 3D simulation. Simple corrections of the 3D effect like the consideration of a mask CD offset or dose offset fail. Apart from that, 2D simulation in conjunction with a well calibrated resist model is sufficient for delivering reliable predictions for process window, MEEF, and CD.

  4. 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.

  5. Set Size and Mask Duration Do Not Interact in Object-Substitution Masking

    ERIC Educational Resources Information Center

    Argyropoulos, Ioannis; Gellatly, Angus; Pilling, Michael; Carter, Wakefield

    2013-01-01

    Object-substitution masking (OSM) occurs when a mask, such as four dots that surround a brief target item, onsets simultaneously with the target and offsets a short time after the target, rather than simultaneously with it. OSM is a reduction in accuracy of reporting the target with the temporally trailing mask, compared with the simultaneously…

  6. Experimental validation of novel mask technology to reduce mask 3D effects

    NASA Astrophysics Data System (ADS)

    Van Look, Lieve; Philipsen, Vicky; Hendrickx, Eric; Davydova, Natalia; Wittebrood, Friso; de Kruif, Robert; van Oosten, Anton; Miyazaki, Junji; Fliervoet, Timon; van Schoot, Jan; Neumann, Jens Timo

    2015-10-01

    Traditional EUV masks, with absorber on top of the multi-layer (ML) mirror, generally suffer from mask 3D effects: H/V shadowing, best focus shifts through pitch and pattern shifts through focus. These effects reduce the overlapping process window, complicate optical proximity correction and generate overlay errors. With further pitch scaling, these mask 3D effects are expected to become stronger, increasing the need for a compensation strategy. In this study, we have proven by simulations and experiments that alternative mask technologies can lower mask 3D effects and therefore have the potential to improve the imaging of critical EUV layers. We have performed an experimental imaging study of a prototype etched ML mask, which has recently become available. This prototype alternative mask has only half the ML mirror thickness (20 Mo/Si pairs) and contains no absorber material at all. Instead, the ML mirror is etched away to the substrate at the location of the dark features. For this etched ML mask, we have compared the imaging performance for mask 3D related effects to that of a standard EUV mask, using wafer exposures at 0.33 NA. Experimental data are compared to the simulated predictions and the benefits and drawbacks of such an alternative mask are shown. Besides the imaging performance, we will also discuss the manufacturability challenges related to the etched ML mask technology.

  7. Alternative EUV mask technology to compensate for mask 3D effects

    NASA Astrophysics Data System (ADS)

    Van Look, Lieve; Philipsen, Vicky; Hendrickx, Eric; Vandenberghe, Geert; Davydova, Natalia; Wittebrood, Friso; de Kruif, Robert; van Oosten, Anton; Miyazaki, Junji; Fliervoet, Timon; van Schoot, Jan; Neumann, Jens Timo

    2015-07-01

    Traditional EUV masks, with absorber on top of the multi-layer (ML) mirror, generally suffer from mask 3D effects: H/V shadowing, best focus shifts through pitch and pattern shifts through focus. These effects reduce the overlapping process window, complicate optical proximity correction and generate overlay errors. With further pitch scaling, these mask 3D effects are expected to become stronger, increasing the need for a compensation strategy. In this study, we have proven by simulations and experiments that alternative mask technologies can lower mask 3D effects and therefore have the potential to improve the imaging of critical EUV layers. We have performed an experimental imaging study of a prototype Etched ML mask, which has recently become available. This prototype alternative mask has only half the ML mirror thickness (20 Mo/Si pairs) and contains no absorber material at all. Instead, the ML mirror is etched away to the substrate at the location of the dark features. For this Etched ML mask, we have compared the imaging performance for mask 3D related effects to that of a standard EUV mask, using wafer exposures at 0.33 NA. Experimental data are compared to the simulated predictions and the benefits and drawbacks of such an alternative mask are shown. Besides the imaging performance, we will also discuss the manufacturability challenges related to the etched ML mask technology.

  8. Experimental validation of novel EUV mask technology to reduce mask 3D effects

    NASA Astrophysics Data System (ADS)

    Van Look, Lieve; Philipsen, Vicky; Hendrickx, Eric; Davydova, Natalia; Wittebrood, Friso; de Kruif, Robert; van Oosten, Anton; Miyazaki, Junji; Fliervoet, Timon; van Schoot, Jan; Neumann, Jens Timo

    2015-09-01

    Traditional EUV masks, with absorber on top of the multi-layer (ML) mirror, generally suffer from mask 3D effects: H/V shadowing, best focus shifts through pitch and pattern shifts through focus. These effects reduce the overlapping process window, complicate optical proximity correction and generate overlay errors. With further pitch scaling, these mask 3D effects are expected to become stronger, increasing the need for a compensation strategy. In this study, we have proven by simulations and experiments that alternative mask technologies can lower mask 3D effects and therefore have the potential to improve the imaging of critical EUV layers. We have performed an experimental imaging study of a prototype etched ML mask, which has recently become available. This prototype alternative mask has only half the ML mirror thickness (20 Mo/Si pairs) and contains no absorber material at all. Instead, the ML mirror is etched away to the substrate at the location of the dark features. For this etched ML mask, we have compared the imaging performance for mask 3D related effects to that of a standard EUV mask, using wafer exposures at 0.33 NA. Experimental data are compared to the simulated predictions and the benefits and drawbacks of such an alternative mask are shown. Besides the imaging performance, we will also discuss the manufacturability challenges related to the etched ML mask technology.

  9. Redesign of an Open-System Oxygen Face Mask With Mainstream Capnometer for Children.

    PubMed

    Napolitano, Natalie; Nishisaki, Akira; Buffman, Hayley S; Leffelman, Jessica; Maltese, Matthew R; Nadkarni, Vinay M

    2017-01-01

    Partial pressure of end-tidal carbon dioxide (PETCO2 ) monitoring in children is important to detect apnea or hypopnea early to intervene before hypoxemia develops. Monitoring PETCO2 in children without a tracheal tube is challenging. To improve PETCO2 measurement accuracy in a commercially available mask with a mainstream CO2 detector, we implemented design changes with deform-and-hold shaping technology and anterior-posterior adjustment of the expiratory gas flow cup. Two sizes of redesigned face masks (small for 7-20 kg, medium for 10-40 kg) were evaluated. Initial bench testing used a simulator modeling a spontaneously breathing infant and child with a natural airway. An infant/child manikin head was connected to the breathing lung simulator. A mass flow controller provided expiratory CO2. Mask fit was then evaluated on healthy human subjects to identify anatomical features associated with good fit, defined as square shape capnography waveform during expiration. A 3-dimensional digital scan was used to quantify anatomical features. The gaps between face mask rims and facial surface were manually measured. Bench testing revealed a PETCO2 difference of 3.4 ± 1.5 mm Hg between a measured PETCO2 by the redesigned mask and CO2 concentration at trachea, as compared with 6.7 ± 6.2 mm Hg between PETCO2 measured by nasal cannula and trachea (P < .001). In the human mask fit study, 35 children (13 ± 4 kg) with the small mask and 38 (24 ± 8 kg) with the medium mask were evaluated. Capnography tracing was successfully obtained in 86% of the small and 100% of the medium masks. In children with small-size masks, the gap between the face mask rim and the child's face was not statistically different among those with good mask fit and without (1.0 ± 1.5 mm vs 1.4 ± 1.9 mm, P = .73). PETCO2 measurement by a redesigned open-system face mask with a mainstream CO2 detector was accurate in the bench setting. The redesigned face mask can attain good mask fit and accurate

  10. Hybrid source mask optimization for robust immersion lithography.

    PubMed

    Ma, Xu; Han, Chunying; Li, Yanqiu; Wu, Bingliang; Song, Zhiyang; Dong, Lisong; Arce, Gonzalo R

    2013-06-20

    To keep pace with the shrinkage of critical dimension, source and mask optimization (SMO) has emerged as a promising resolution enhancement technique to push the resolution of 193 nm argon fluoride immersion lithography systems. However, most current pixelated SMO approaches relied on scalar imaging models that are no longer accurate for immersion lithography systems with hyper-NA (NA>1). This paper develops a robust hybrid SMO (HSMO) algorithm based on a vector imaging model capable of effectively improving the robustness of immersion lithography systems to defocus and dose variations. The proposed HSMO algorithm includes two steps. First, the individual source optimization approach is carried out to rapidly reduce the cost function. Subsequently, the simultaneous SMO approach is applied to further improve the process robustness by exploiting the synergy in the joint optimization of source and mask patterns. The conjugate gradient method is used to update the source and mask pixels. In addition, a source regularization approach and source postprocessing are both used to improve the manufacturability of the optimized source patterns. Compared to the mask optimization method, the HSMO algorithm achieves larger process windows, i.e., extends the depth of focus and exposure latitude, thus more effectively improving the process robustness of 45 nm immersion lithography systems.

  11. Assessment of molecular contamination in mask pod

    NASA Astrophysics Data System (ADS)

    Foray, Jean Marie; Dejaune, Patrice; Sergent, Pierre; Gough, Stuart; Cheung, D.; Davenet, Magali; Favre, Arnaud; Rude, C.; Trautmann, T.; Tissier, Michel; Fontaine, H.; Veillerot, M.; Avary, K.; Hollein, I.; Lerit, R.

    2008-04-01

    Context/ study Motivation: Contamination and especially Airbone Molecular Contamination (AMC) is a critical issue for mask material flow with a severe and fairly unpredictable risk of induced contamination and damages especially for 193 nm lithography. It is therefore essential to measure, to understand and then try to reduce AMC in mask environment. Mask material flow was studied in a global approach by a pool of European partners, especially within the frame of European MEDEA+ project, so called "MUSCLE". This paper deals with results and assessment of mask pod environment in term of molecular contamination in a first step, then in a second step preliminary studies to reduce mask pod influence and contamination due to material out gassing. Approach and techniques: A specific assessment of environmental / molecular contamination along the supply chain was performed by all partners. After previous work presented at EMLC 07, further studies were performed on real time contamination measurement pod at different sites locations (including Mask manufacturing site, blank manufacturing sites, IC fab). Studies were linked to the main critical issues: cleaning, storage, handling, materials and processes. Contamination measurement campaigns were carried out along the mask supply chain using specific Adixen analyzer in order to monitor in real time organic contaminants (ppb level) in mask pods. Key results would be presented: VOC, AMC and humidity level on different kinds of mask carriers, impact of basic cleaning on pod outgassing measurement (VOC, NH3), and process influence on pod contamination... In a second step, preliminary specific pod conditioning studies for better pod environment were performed based on Adixen vacuum process. Process influence had been experimentally measured in term of molecular outgassing from mask pods. Different AMC experimental characterization methods had been carried out leading to results on a wide range of organic and inorganic

  12. Fast, low-complexity mask design

    NASA Astrophysics Data System (ADS)

    Cobb, Nicolas B.; Zakhor, Avideh

    1995-05-01

    In previous work, Cobb and Zakhor developed an automated mask design algorithm using optimization to produce masks which can print at smaller feature sizes. In this work, we build upon our previous approach with special regard to computational efficiency and mask manufacturability to produce an Optical Proximity Correction (OPC) algorithm which operates orders of magnitude faster and produces simpler optimized masks. The algorithm can be used for OPC of Manhattan geometry masks for which phase assignment has been previously completed. Therefore, the OPC problem is divorced from phase-mask design and the two tasks are performed independently. Our algorithm decomposes the mask features into edges and corners which can be moved from their original placements to improve the image characteristics. The resulting optimization algorithm inherently requires computation of O((rho) o3) where (rho) o is the density of edges and corners on the mask. A major feature of the algorithm is a new fast intensity computation technique which uses lookup tables to achieve single point intensity computation on the order of O(Na (DOT) Mr) where Na is the order of approximation to the optical system and Mr is the number of rectangles in the mask region description. The single point intensity computation time is typically around 300 microsecond(s) ec for fairly complicated masks on a HP 700 series workstation. The resulting algorithm optimized a 36 X 36 micrometers 2 test mask in 6 iterations at 11 seconds per iteration pass on the same machine. The new techniques make the described algorithm viable for a production environment with k1 as low as k1 equals 0.4.

  13. Shadows Alter Facial Expressions of Noh Masks

    PubMed Central

    Kawai, Nobuyuki; Miyata, Hiromitsu; Nishimura, Ritsuko; Okanoya, Kazuo

    2013-01-01

    Background A Noh mask, worn by expert actors during performance on the Japanese traditional Noh drama, conveys various emotional expressions despite its fixed physical properties. How does the mask change its expressions? Shadows change subtly during the actual Noh drama, which plays a key role in creating elusive artistic enchantment. We here describe evidence from two experiments regarding how attached shadows of the Noh masks influence the observers’ recognition of the emotional expressions. Methodology/Principal Findings In Experiment 1, neutral-faced Noh masks having the attached shadows of the happy/sad masks were recognized as bearing happy/sad expressions, respectively. This was true for all four types of masks each of which represented a character differing in sex and age, even though the original characteristics of the masks also greatly influenced the evaluation of emotions. Experiment 2 further revealed that frontal Noh mask images having shadows of upward/downward tilted masks were evaluated as sad/happy, respectively. This was consistent with outcomes from preceding studies using actually tilted Noh mask images. Conclusions/Significance Results from the two experiments concur that purely manipulating attached shadows of the different types of Noh masks significantly alters the emotion recognition. These findings go in line with the mysterious facial expressions observed in Western paintings, such as the elusive qualities of Mona Lisa’s smile. They also agree with the aesthetic principle of Japanese traditional art “yugen (profound grace and subtlety)”, which highly appreciates subtle emotional expressions in the darkness. PMID:23940748

  14. A novel 3D constellation-masked method for physical security in hierarchical OFDMA system.

    PubMed

    Zhang, Lijia; Liu, Bo; Xin, Xiangjun; Liu, Deming

    2013-07-01

    This paper proposes a novel 3D constellation-masked method to ensure the physical security in hierarchical optical orthogonal frequency division multiplexing access (OFDMA) system. The 3D constellation masking is executed on the two levels of hierarchical modulation and among different OFDM subcarriers, which is realized by the masking vectors. The Lorenz chaotic model is adopted for the generation of masking vectors in the proposed scheme. A 9.85 Gb/s encrypted hierarchical QAM OFDM signal is successfully demonstrated in the experiment. The performance of illegal optical network unit (ONU) with different masking vectors is also investigated. The proposed method is demonstrated to be secure and efficient against the commonly known attacks in the experiment.

  15. Integrating RET and mask manufacturability in designs for local interconnect for sub-100-nm trenches

    NASA Astrophysics Data System (ADS)

    Kachwala, Nishrin; Brist, Travis E.; Farnbach, Rick S.

    2004-12-01

    Model based OPC for low k1 lithography has a large impact on mask cost, and hence must be optimized with respect to mask manufacturability and mask cost without sacrificing device performance. Design IP blocks not designed with the lithography process in mind (not "litho friendly") require more complex RET/OPC solutions, which can in turn result in unnecessary increases in the mask cost and turn around time. These blocks are typically replicated many times across a design and can therefore have a compounding effect. Design for manufacturing (DFM) techniques verify and alleviate complex interactions between design and process. DFM can be applied at various stages in your design-to-silicon flow. We will discuss how these DFM methods are applied and implemented at Cypress. We will also show how design rules are defined and present several methods for injecting OPC/RET awareness into the designs prior to mask manufacture.

  16. The attentional blink is not affected by backward masking of T2, T2-mask SOA, or level of T2 impoverishment.

    PubMed

    Jannati, Ali; Spalek, Thomas M; Lagroix, Hayley E P; Di Lollo, Vincent

    2012-02-01

    Identification of the second of two targets (T2) is impaired when presented shortly after the first (T1). This attentional blink (AB) is thought to arise from a delay in T2 processing during which T2 is vulnerable to masking. Conventional studies have measured T2 accuracy which is constrained by the 100% ceiling. We avoided this problem by using a dynamic threshold-tracking procedure that is inherently free from ceiling constraints. In two experiments we examined how AB magnitude is affected by three masking-related factors: (a) presence/absence of T2 mask, (b) T2-mask stimulus onset asynchrony (SOA), and (c) level of T2 impoverishment (signal-to-noise ratio [SNR]). In Experiment 1, overall accuracy decreased with T2-mask SOA. The magnitude of the AB, however, was invariant with SOA and with mask presence/absence. Experiment 2 further showed that the AB was invariant with T2 SNR. The relationship among mask presence/absence, SOA, and T2 SNR and the AB is encompassed in a qualitative model.

  17. Implicit Semantic Perception in Object Substitution Masking

    ERIC Educational Resources Information Center

    Goodhew, Stephanie C.; Visser, Troy A. W.; Lipp, Ottmar V.; Dux, Paul E.

    2011-01-01

    Decades of research on visual perception has uncovered many phenomena, such as binocular rivalry, backward masking, and the attentional blink, that reflect "failures of consciousness". Although stimuli do not reach awareness in these paradigms, there is evidence that they nevertheless undergo semantic processing. Object substitution masking (OSM),…

  18. Spatial processing and visual backward masking.

    PubMed

    Herzog, Michael H

    2008-07-15

    Most theories of visual masking focus prima-rily on the temporal aspects of visual information processing, strongly neglecting spatial factors. In recent years, however, we have shown that this position is not tenable. Spatial aspects cannot be neglected in metacontrast, pattern and un-masking. Here, we review these results.

  19. Spatial processing and visual backward masking

    PubMed Central

    Herzog, Michael H.

    2008-01-01

    Most theories of visual masking focus prima-rily on the temporal aspects of visual information processing, strongly neglecting spatial factors. In recent years, however, we have shown that this position is not tenable. Spatial aspects cannot be neglected in metacontrast, pattern and un-masking. Here, we review these results. PMID:20517500

  20. GEWEX-RFA Land-Ocean Mask

    Atmospheric Science Data Center

    2017-05-25

    GEWEX RFA Land-Ocean Mask A 2.5° resolution land-ocean mask has been developed for the Radiative Flux Assessment. It can be used ... creating global, regional, or zonal time series for land or ocean. Format - Pixels are arranged as in global map standard . ...

  1. A facial mask comprising Dead Sea mud.

    PubMed

    Abu-Jdayil, Basim; Mohameed, Hazim A

    2006-01-01

    Many investigators have proved that Dead Sea salt and mud are useful in treating skin disorders and skin diseases. Therefore, the black mud has been extensively used as a base for the preparation of soaps, creams, and unguents for skin care. This study concerns a facial mask made mainly of Dead Sea mud. The effects of temperature and shearing conditions on the rheological behavior of the facial mask were investigated. The mud facial mask exhibited a shear thinning behavior with a yield stress. It was found that the apparent viscosity of the mask has a strong dependence on the shear rate as well as on the temperature. The facial mask exhibited a maximum yield stress and very shear thinning behavior at 40 degrees C, which is attributed to the gelatinization of the polysaccharide used to stabilize the mud particles. On the other hand, the mud mask exhibited a time-independent behavior at low temperatures and shear rates and changed to a thixotropic behavior upon increasing both the temperature and the shear rate. The shear thinning and thixotropic behaviors have a significant importance in the ability of the facial mask to spread on the skin: the Dead Sea mud mask can break down for easy spreading, and the applied film can gain viscosity instantaneously to resist running. Moreover, particle sedimentation, which in this case would negatively affect consumer acceptance of the product, occurs slowly due to high viscosity at rest conditions.

  2. 21 CFR 868.5590 - Scavenging mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification....

  3. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask....

  4. 21 CFR 868.5590 - Scavenging mask.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification. A...

  5. EUV mask pilot line at Intel Corporation

    NASA Astrophysics Data System (ADS)

    Stivers, Alan R.; Yan, Pei-Yang; Zhang, Guojing; Liang, Ted; Shu, Emily Y.; Tejnil, Edita; Lieberman, Barry; Nagpal, Rajesh; Hsia, Kangmin; Penn, Michael; Lo, Fu-Chang

    2004-12-01

    The introduction of extreme ultraviolet (EUV) lithography into high volume manufacturing requires the development of a new mask technology. In support of this, Intel Corporation has established a pilot line devoted to encountering and eliminating barriers to manufacturability of EUV masks. It concentrates on EUV-specific process modules and makes use of the captive standard photomask fabrication capability of Intel Corporation. The goal of the pilot line is to accelerate EUV mask development to intersect the 32nm technology node. This requires EUV mask technology to be comparable to standard photomask technology by the beginning of the silicon wafer process development phase for that technology node. The pilot line embodies Intel's strategy to lead EUV mask development in the areas of the mask patterning process, mask fabrication tools, the starting material (blanks) and the understanding of process interdependencies. The patterning process includes all steps from blank defect inspection through final pattern inspection and repair. We have specified and ordered the EUV-specific tools and most will be installed in 2004. We have worked with International Sematech and others to provide for the next generation of EUV-specific mask tools. Our process of record is run repeatedly to ensure its robustness. This primes the supply chain and collects information needed for blank improvement.

  6. [Use of respiratory masks in healthcare workers].

    PubMed

    Ciotti, C; Bouvet, E; Abiteboul, D

    2008-08-01

    Two different types of filtering respiratory masks are available in healthcare settings. The first ones are used to protect patients from droplets coming from the mouth of healthcare workers (HCW) and the second ones are protective masks. For the moment, we lack information regarding application of Ministry of Health recommendations and on adherence of HCW to mask use. Geres, the HCW exposure risk study group, and the INRS, are now conducting a survey in several hospitals in France to evaluate the use of respiratory masks in healthcare settings. Two phases are planned. Phase I is a self survey using a questionnaire for occupational doctors and hygienists and phase II includes three steps on HCW behavior: evaluation of knowledge and practice concerning respiratory masks, evaluation of respiratory mask use, evaluation of wear and fit test in a context of airborne isolation with a FFP1 and FFP2 respiratory mask. Phase I is finished and phase II is beginning. The first phase I data show that the Ministry's recommendations are observed: respiratory masks are available, written recommendations are present; information and training are organized for healthcare workers. Phase II results are not available yet.

  7. Computing Challenges in Coded Mask Imaging

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald

    2009-01-01

    This slide presaentation reviews the complications and challenges in developing computer systems for Coded Mask Imaging telescopes. The coded mask technique is used when there is no other way to create the telescope, (i.e., when there are wide fields of view, high energies for focusing or low energies for the Compton/Tracker Techniques and very good angular resolution.) The coded mask telescope is described, and the mask is reviewed. The coded Masks for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) instruments are shown, and a chart showing the types of position sensitive detectors used for the coded mask telescopes is also reviewed. Slides describe the mechanism of recovering an image from the masked pattern. The correlation with the mask pattern is described. The Matrix approach is reviewed, and other approaches to image reconstruction are described. Included in the presentation is a review of the Energetic X-ray Imaging Survey Telescope (EXIST) / High Energy Telescope (HET), with information about the mission, the operation of the telescope, comparison of the EXIST/HET with the SWIFT/BAT and details of the design of the EXIST/HET.

  8. Comparison of face masks in the bag-mask ventilation of a manikin.

    PubMed

    Redfern, D; Rassam, S; Stacey, M R; Mecklenburgh, J S

    2006-02-01

    We conducted a study investigating the effectiveness of four face mask designs in the bag-mask ventilation of a special manikin adapted to simulate a difficult airway. Forty-eight anaesthetists volunteered to bag-mask ventilate the manikin for 3 min with four different face masks. The primary outcome of the study was to calculate mean percentage leak from the face masks over 3 min. Anaesthetists were also asked to rate the face masks using a visual analogue score. The single-use scented intersurgical face mask had the lowest mean leak (20%). This was significantly lower than the mean leak from the single-use, cushioned 7,000 series Air Safety Ltd. face mask (24%) and the reusable silicone Laerdal face mask (27%) but not significantly lower than the mean leak from the reusable anatomical intersurgical face mask (23%). There was a large variation in both performance and satisfaction between anaesthetists with each design. This highlights the importance of having a variety of face masks available for emergency use.

  9. Enhancement of global CD correction and data processing in EB mask writer EBM-8000

    NASA Astrophysics Data System (ADS)

    Matsumoto, Hiroshi; Kato, Yasuo; Motosugi, Tomoo; Yashima, Jun; Abe, Takayuki; Nakayamada, Noriaki; Yoshitake, Shusuke; Hattori, Kiyoshi

    2011-11-01

    We report our development of fogging effect correction method aimed for EBM-8000, our newest series of EB mask writers for mask production of 22nm half-pitch generation and for mask development of 16nm half-pitch generation. We refined the method of fogging effect correction by taking account of dose modulation for proximity effects correction and loading effect correction into fogging effect correction, greatly reducing theoretical error. Writing experiment has shown that our method based on the threshold dose model is effective, though deviation from the model is observed.

  10. Nasal mask ventilation is better than face mask ventilation in edentulous patients

    PubMed Central

    Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

    2016-01-01

    Background and Aims: Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Material and Methods: Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. Results: A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Conclusion: Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients. PMID:27625477

  11. Nasal mask ventilation is better than face mask ventilation in edentulous patients.

    PubMed

    Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

    2016-01-01

    Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients.

  12. Lithographic plane review (LPR) for sub-32nm mask defect disposition

    NASA Astrophysics Data System (ADS)

    Tolani, Vikram; Peng, Danping; He, Lin; Hwa, George; Chang, Hsien-Min; Dai, Grace; Corcoran, Noel; Dam, Thuc; Pang, Linyong; Tuo, Laurent C.; Chen, C. J.; Lai, Rick

    2010-09-01

    As optical lithography continues to extend into low-k1 regime, resolution of mask patterns under mask inspection optical conditions continues to diminish. Furthermore, as mask complexity and MEEF has also increased, it requires detecting even smaller defects in the already narrower pitch mask patterns. This leaves the mask inspection engineer with the option to either purchase a higher resolution mask inspection tool or increase the detector sensitivity on the existing inspection system or maybe even both. In order to meet defect sensitivity requirements in critical features of sub-32nm node designs, increasing sensitivity typically results in increased nuisance (i.e., small sub-specification) defect detection by 5-20X defects making post-inspection defect review non-manufacturable. As a solution for automatically dispositioning the increased number of nuisance and real defects detected at higher inspection sensitivity, Luminescent has successfully extended Inverse Lithography Technology (ILT) and its patented level-set methods to reconstruct the defective mask from its inspection image, and then perform simulated AIMS dispositioning on the reconstructed mask. In this technique, named Lithographic Plane Review (LPR), inspection transmitted and reflected light images of the test (i.e. defect) and reference (i.e., corresponding defect-free) regions are provided to the "inversion" engine which then computes the corresponding test and reference mask patterns. An essential input to this engine is a well calibrated model incorporating inspection tool optics, mask processing and 3D effects, and also the subsequent AIMS tool optics to be able to then simulate the aerial image impact of the defects. This flow is equivalent to doing an actual AIMS tool measurement of every defect detected during mask inspection, while at the same time maintaining inspection at high enough resolution. What makes this product usable in mask volume production is the high degree of accuracy of

  13. Mask tuning for process window improvement

    NASA Astrophysics Data System (ADS)

    Buttgereit, Ute; Birkner, Robert; Graitzer, Erez; Cohen, Avi; Triulzi, Benedetta; Romeo, Carmelo

    2011-03-01

    For the next years optical lithography stays at 193nm with a numerical aperture of 1.35. Mask design becomes more complex, mask and lithography specifications tighten. The k1 factor comes close to 0.25 which leads to a tremendously increased Mask Error Enhancement Factor (MEEF). This means that CD errors on mask are getting highly amplified on wafer. Process control becomes more important than ever. Accurate process control is a key factor to success to maintain a high yield in chip production. One key parameter to ensure a high and reliable functionality for any integrated circuit is the critical dimension uniformity (CDU). There are different contributors which impact the intra-field CD performance at wafer such as mask CD uniformity, scanner fingerprint, resist process etc. In the present work we focus on improvement of mask CD signature which is one of the main contributors to intra-field CD uniformity. The mask CD uniformity has been measured by WLCD32 which measures the CD based on proven aerial image technology. Based on this CD input the CD uniformity was corrected by CDC200TM and afterwards verified by WLCD32 measurement. The CDC200TM tool utilizes an ultrafast femto-second laser to write intra-volume shading elements (Shade-In ElementsTM) inside the bulk material of the mask. By adjusting the density of the shading elements, the light transmission through the mask is locally changed in a manner that improves wafer CDU when the corrected mask is printed. Additionally, the impact of the improved CD uniformity on the lithography process window was investigated. Goal of the work is to establish a process flow for mask CD uniformity improvement based on mask CD metrology by WLCD32 and mask CD uniformity control by CDC200TM and to verify its impact on the lithography process window. The proposed process flow will be validated by wafer prints. It was shown that the WLCD32 has an excellent correlation to wafer data and an outstanding CD repeatability. It provides

  14. Masking property of quantum random cipher with phase mask encryption

    NASA Astrophysics Data System (ADS)

    Sohma, Masaki; Hirota, Osamu

    2014-10-01

    The security analysis of physical encryption protocol based on coherent pulse position modulation (CPPM) originated by Yuen is one of the most interesting topics in the study of cryptosystem with a security level beyond the Shannon limit. Although the implementation of CPPM scheme has certain difficulty, several methods have been proposed recently. This paper deals with the CPPM encryption in terms of symplectic transformation, which includes a phase mask encryption as a special example, and formulates a unified security analysis for such encryption schemes. Specifically, we give a lower bound of Eve's symbol error probability using reliability function theory to ensure that our proposed system exceeds the Shannon limit. Then we assume the secret key is given to Eve after her heterodyne measurement. Since this assumption means that Eve has a great advantage in the sense of the conventional cryptography, the lower bound of her error indeed ensures the security level beyond the Shannon limit. In addition, we show some numerical examples of the security performance.

  15. Implications of Sustained and Transient Channels for Theories of Visual Pattern Masking, Saccadic Suppression, and Information Processing

    ERIC Educational Resources Information Center

    Breitmeyer, Bruno G.; Ganz, Leo

    1976-01-01

    This paper reviewed briefly the major types of masking effects obtained with various methods and the major theories or models that have been proposed to account for these effects, and outlined a three-mechanism model of visual pattern masking based on psychophysical and neurophysiological properties of the visual system. (Author/RK)

  16. Actinic EUV mask inspection beyond 0.25 NA

    SciTech Connect

    Goldberg, Kenneth A.; Mochi, Iacopo; Anderson, Erik H.; Rekawa, Seno B.; Kemp, Charles D.; Huh, S.; Han, H.-S.

    2008-08-06

    Operating at EUV wavelengths, the SEMATECH Berkeley Actinic Inspection Tool (AIT) is a zoneplate microscope that provides high quality aerial image measurements in routine operations for SEMATECH member companies. We have upgraded the optical performance of the AIT to provide multiple image magnifications, and several inspection NA values up to 0.35 NA equivalent (0.0875 mask-side). We report on the improved imaging capabilities including resolution below 100-nm on the mask side (25 nm, 4x wafer equivalent). EUV reticles are intricate optical systems made from of several materials with wavelength-specific optical properties. The combined interactions of the substrate, multilayer-stack, buffer layer and absorber layer produce a reflected EUV optical field that is challenging to model accurately, and difficult to fully assess without actinic at-wavelength inspection. Understanding the aerial image from lithographic printing alone is complicated by photoresist properties. The AIT is now used to investigate mask issues such as amplitude and phase defect printability, pattern repair techniques, contamination, inspection damage, and mask architecture. The AIT has a 6{sup o} illumination angle, and high-resolution exposure times are typically 20 seconds per image. The AIT operates semi-automatically capturing through-focus imaging series with step sizes as small as 0.1 {micro}m (0.5-0.8 {micro}m are typical), and a step resolution of 0.05 {micro}m. We believe it is the most advanced EUV mask inspection tool in operation today. In the AIT, an EUV image of the mask is projected by a zoneplate lens with high magnification (680-910x) onto a CCD camera. The CCD over-samples the image, providing equivalent pixel sizes down to 15 nm in mask coordinates-several image pixels per resolution element. The original AIT zoneplate specifications were designed to emulate the resolution of a 0.25-NA 4x stepper, and thorough benchmarking analysis of the aberrations, flare, contrast

  17. Pupil Masks for Spectrophotometry of Transiting Exoplanets

    NASA Astrophysics Data System (ADS)

    Itoh, Satoshi; Matsuo, Taro; Goda, Shohei; Shibai, Hiroshi; Sumi, Takahiro

    2017-09-01

    Spectrophotometric stability, which is crucial in the spectral characterization of transiting exoplanets, is affected by photometric variations arising from field-stop loss in space telescopes with pointing jitter or primary mirror deformation. This paper focuses on a new method for removing slit-loss or field-stop-loss photometric variation through the use of a pupil mask. Two types of pupil function are introduced: the first uses conventional (e.g., Gaussian or hyper-Gaussian) apodizing patterns; whereas the second, which we call a block-shaped mask, employs a new type of pupil mask designed for high photometric stability. A methodology for the optimization of a pupil mask for transit observations is also developed. The block-shaped mask can achieve a photometric stability of 10-5 for a nearly arbitrary field-stop radius when the pointing jitter is smaller than approximately 0.7λ /D and a photometric stability of 10-6 at a pointing jitter smaller than approximately 0.5λ /D. The impact of optical aberrations and mask imperfections upon mask performance is also discussed.

  18. Intact crowding and temporal masking in dyslexia.

    PubMed

    Doron, Adi; Manassi, Mauro; Herzog, Michael H; Ahissar, Merav

    2015-01-01

    Phonological deficits in dyslexia are well documented. However, there is an ongoing discussion about whether visual deficits limit the reading skills of people with dyslexia. Here, we investigated visual crowding and backward masking. We presented a Vernier (i.e., two vertical bars slightly offset to the left or right) and asked observers to indicate the offset direction. Vernier stimuli are visually similar to letters and are strongly affected by crowding, even in the fovea. To increase task difficulty, Verniers are often followed by a mask (i.e., backward masking). We measured Vernier offset discrimination thresholds for the basic Vernier task, under crowding, and under backward masking, in students with dyslexia (n = 19) and age and intelligence matched students (n = 27). We found no group differences in any of these conditions. Controls with fast visual processing (good backward masking performance), were faster readers. By contrast, no such correlation was found among the students with dyslexia, suggesting that backward masking does not limit their reading efficiency. These findings indicate that neither elevated crowding nor elevated backward masking pose a bottleneck to reading skills of people with dyslexia.

  19. Mask Fabrication Using Electron Beam Exposure System

    NASA Astrophysics Data System (ADS)

    Watakabe, Y.; Shigetomi, A.; Morimoto, H.; Kato, T.

    1981-07-01

    This study describes the results of feature size distribution, pattern location accuracy and level to level registration error on chrominum master masks fabricated by EeBES-40. This system has the capability of high speed electron beam blanking at 40MHz, the capacity for large size masks (with 6 inch mask cassette), and the automatic cassette handling system. OEBR-100(PGMA), as the electron beam negative resist, is used for 5 inch and 6 inch chrominum masks. The chrominum etching process is used for both wet and dry plasma technology. Test patterns and 64 K bit memory TEG, as the practical pattern, are used in this study. More than 40 measurements are taken, uniformly distributed over 96 to 112mm square, and the feature size distribution is measured by a laser interferometer X-Y measuring system. Pattern location accuracy and level to level registration error are obtained using EeBES-40 quality assurance programs called MARKET/PLOTMARKET. This program operates by scanning over the resist image of the test pattern, utilizing the normal fiducial mark location hardware. The followinc results are obtained; (1) Feature size distribution within 6 inch mask : -/+0.1 μm (2) Level-to-level registration error2 : less than 0.1 pm High quality masks with about 0.02 defects/cm2 , and rapid throughput of 6 hr./10 masks using the auto-matic 10-cassette handling system are obtained.

  20. The Sensitivity of Coded Mask Telescopes

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald K.

    2008-01-01

    Simple formulae are often used to estimate the sensitivity of coded mask X-ray or gamma-ray telescopes, but t,hese are strictly only applicable if a number of basic assumptions are met. Complications arise, for example, if a grid structure is used to support the mask elements, if the detector spatial resolution is not good enough to completely resolve all the detail in the shadow of the mask or if any of a number of other simplifying conditions are not fulfilled. We derive more general expressions for the Poisson-noise-limited sensitivity of astronomical telescopes using the coded mask technique, noting explicitly in what circumstances they are applicable. The emphasis is on using nomenclature and techniques that result in simple and revealing results. Where no convenient expression is available a procedure is given which allows the calculation of the sensitivity. We consider certain aspects of the optimisation of the design of a coded mask telescope and show that when the detector spatial resolution and the mask to detector separation are fixed, the best source location accuracy is obtained when the mask elements are equal in size to the detector pixels.

  1. Achievements and challenges of EUV mask imaging

    NASA Astrophysics Data System (ADS)

    Davydova, Natalia; van Setten, Eelco; de Kruif, Robert; Connolly, Brid; Fukugami, Norihito; Kodera, Yutaka; Morimoto, Hiroaki; Sakata, Yo; Kotani, Jun; Kondo, Shinpei; Imoto, Tomohiro; Rolff, Haiko; Ullrich, Albrecht; Lammers, Ad; Schiffelers, Guido; van Dijk, Joep

    2014-07-01

    The impact of various mask parameters on CDU combined in a total mask budget is presented, for 22 nm lines, for reticles used for NXE:3300 qualification. Apart from the standard mask CD measurements, actinic spectrometry of multilayer is used to qualify reflectance uniformity over the image field; advanced 3D metrology is applied for absorber profile characterization including absorber height and side wall angle. The predicted mask impact on CDU is verified using actual exposure data collected on multiple NXE:3300 scanners. Mask 3D effects are addressed, manifesting themselves in best focus shifts for different structures exposed with off-axis illumination. Experimental NXE:3300 results for 16 nm dense lines and 20 nm (semi-)isolated spaces are shown: best focus range reaches 24 nm. A mitigation strategy by absorber height optimization is proposed based on experimental results of a special mask with varying absorber heights. Further development of a black image border for EUV mask is considered. The image border is a pattern free area surrounding image field preventing exposure the image field neighborhood on wafer. Normal EUV absorber is not suitable for this purpose as it has 1-3% EUV reflectance. A current solution is etching of ML down to substrate reducing EUV reflectance to <0.05%. A next step in the development of the black border is the reduction of DUV Out-of-Band reflectance (<1.5%) in order to cope with DUV light present in EUV scanners. Promising results achieved in this direction are shown.

  2. Mask industry assessment trend analysis: 2012

    NASA Astrophysics Data System (ADS)

    Chan, Y. David

    2012-02-01

    Microelectronics industry leaders consistently cite the cost and cycle time of mask technology and mask supply among the top critical issues for lithography. A survey was designed by SEMATECH with input from semiconductor company mask technologists and merchant mask suppliers to objectively assess the overall conditions of the mask industry. With the continued support of the industry, this year's assessment was the tenth in the current series of annual reports. This year's survey is basically the same as the 2005 through 2011 surveys. Questions are grouped into six categories: General Business Profile Information, Data Processing, Yields and Yield Loss Mechanisms, Delivery Times, Returns, and Services. Within each category is a multitude of questions that ultimately produce a detailed profile of both the business and technical status of the critical mask industry. We received data from 11 companies this year, which was a record high since the beginning of the series. The responding companies represented more than 96% of the volume shipped and about 90% of the 2011 revenue for the photomask industry. These survey reports are often used as a baseline to gain perspective on the technical and business status of the mask and microelectronics industries. They will continue to serve as a valuable reference to identify strengths and opportunities. Results can also be used to guide future investments in critical path issues.

  3. Evaluating EUV mask pattern imaging with two EUV microscopes

    SciTech Connect

    Goldberg, Kenneth A.; Takase, Kei; Naulleau, Patrick P.; Han, Hakseung; Barty, Anton; Kinoshita, Hiroo; Hamamoto, Kazuhiro

    2008-02-26

    Aerial image measurement plays a key role in the development of patterned reticles for each generation of lithography. Studying the field transmitted (reflected) from EUV masks provides detailed information about potential disruptions caused by mask defects, and the performance of defect repair strategies, without the complications of photoresist imaging. Furthermore, by measuring the continuously varying intensity distribution instead of a thresholded, binary resist image, aerial image measurement can be used as feedback to improve mask and lithography system modeling methods. Interest in EUV, at-wavelength, aerial image measurement lead to the creation of several research tools worldwide. These tools are used in advanced mask development work, and in the evaluation of the need for commercial at-wavelength inspection tools. They describe performance measurements of two such tools, inspecting the same EUV mask in a series of benchmarking tests that includes brightfield and darkfield patterns. One tool is the SEMATECH Berkeley Actinic Inspection Tool (AIT) operating on a bending magnet beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The AIT features an EUV Fresnel zoneplate microscope that emulates the numerical aperture of a 0.25-NA stepper, and projects the aerial image directly onto a CCD camera, with 700x magnification. The second tool is an EUV microscope (EUVM) operating at the NewSUBARU synchrotron in Hyogo, Japan. The NewSUBARU tool projects the aerial image using a reflective, 30x Schwarzschild objective lens, followed by a 10-200x x-ray zooming tube. The illumination conditions and the imaging etendue are different for the two tools. The benchmarking measurements were used to determine many imaging and performance properties of the tools, including resolution, modulation transfer function (MTF), aberration magnitude, aberration field-dependence (including focal-plane tilt), illumination uniformity, line-edge roughness, and flare

  4. Psychophysical estimates of cochlear phase response: masking by harmonic complexes.

    PubMed

    Lentz, J J; Leek, M R

    2001-12-01

    Harmonic complexes with identical component frequencies and amplitudes but different phase spectra may be differentially effective as maskers. Such harmonic waveforms, constructed with positive or negative Schroeder phases, have similar envelopes and identical long-term power spectra, but the positive Schroeder-phase waveform is typically a less effective masker than the negative Schroeder-phase waveform. These masking differences have been attributed to an interaction between the masker phase spectrum and the phase characteristic of the basilar membrane. To explore this relationship, the gradient of stimulus phase change across masker bandwidth was varied by systematically altering the Schroeder-phase algorithm. Observers detected a signal tone added in-phase to a single component of a masker whose frequencies ranged from 200 to 5000 Hz, with a fundamental frequency of 100 Hz. For signal frequencies of 1000-4000 Hz, differences in masking across the harmonic complexes could be as large as 5-10 dB for phase gradients changing by only 10%. The phase gradient that resulted in a minimum amount of masking varied with signal frequency, with low frequencies masked least effectively by stimuli with rapidly changing component phases and high frequencies masked by stimuli with more shallow phase gradients. A gammachirp filter was implemented to model these results, predicting the qualitative changes in curvature of the phase-byfrequency function estimated from the empirical data: In some cases, small modifications to the gammachirp filter produced better quantitative predictions of curvature changes across frequency, but this filter, as implemented here, was unable to accurately represent all the data.

  5. Neopuff T-piece mask resuscitator: is mask leak related to watching the pressure dial?

    PubMed

    Tracy, Mark B; Klimek, J; Shingde, V; Hinder, M; Maheshwari, R; Tracy, S K

    2010-09-01

    The aim of the study is to compare mask leak and delivered ventilation during Neopuff (NP) mask ventilation in two modes: (i) with NP pressure dial hidden and resuscitator watching chest wall (CW) rise with, (ii) CW movement hidden and resuscitator watching NP pressure dial. Thirty-six participants gave mask ventilation to a modified manikin designed to measure mask leak and delivered ventilation for two minutes in each mode randomly assigned. Paired t-tests were used to analyse differences in mean values. Linear regression was used to determine the association of mask leak with delivered ventilation. Of 7277 inflations analysed, 3621 were observing chest wall mode (CWM) and 3656 observing NP mode (NPM). Mask leak was similar between the groups; 31.6% for CWM and 31.5% (p = 0.56) for NPM. There were no significant differences in airways pressures and expired tidal volumes (TVe) between modes. Mask leak was strongly associated with TVe (R = -0.86 p < 0.0001) and with peak inspiratory pressure (PIP) (R = -0.51 p < 0.0001). TVe was associated with PIP (R = 0.51 p < 0.0001). This study provides reassurance that NP mask leak is not greater when resuscitators watch the NP pressure dial. Mask leak is related to TVe. Mask ventilation training with manikins should include tidal volume measurements. © 2010 The Author(s)/Journal Compilation © 2010 Foundation Acta Paediatrica.

  6. Evaluation of taste-masking effects of pharmaceutical sweeteners with an electronic tongue system.

    PubMed

    Choi, Du Hyung; Kim, Nam Ah; Nam, Tack Soo; Lee, Sangkil; Jeong, Seong Hoon

    2014-03-01

    Electronic tongue systems have been developed for taste measurement of bitter drug substances in accurate taste comparison to development palatable oral formulations. This study was to evaluate the taste masking effect of conventional pharmaceutical sweeteners such as neohesperidin dihydrochalcone, sucrose, sucralose and aspartame. The model drugs were acetaminophen, ibuprofen, tramadol hydrochloride, and sildenafil citrate (all at 20 mM). The degree of bitterness was measured by a multichannel taste sensor system (an electronic tongue). The data was collected by seven sensors and analyzed by a statistical method of principal components analysis (PCA). The effect of taste masking excipient was dependent on the type of model drug. Changing the concentration of taste masking excipients affected the sensitivity of taste masking effect according to the type of drug. As the excipient concentration increased, the effect of taste masking increased. Moreover, most of the sensors showed a concentration-dependent pattern of the taste-masking agents as higher concentration provided higher selectivity. This might indicate that the sensors can detect small concentration changes of a chemical in solution. These results suggest that the taste masking could be evaluated based on the data of the electronic tongue system and that the formulation development process could be performed in a more efficient way.

  7. Behavior of imperfect band-limited coronagraphic masks in a high-contrast imaging system.

    PubMed

    Sidick, Erkin; Wilson, Daniel W

    2007-03-20

    We investigate the behavior of imperfect band-limited occulting masks in a high-contrast imaging system through modeling and simulations. Grayscale masks having 1D Sinc(2) (linear-Sinc(2)) amplitude transmission coefficient (Sinc(4) intensity transmittance) profiles as well as optical density and wavelength-dependent parasitic phases are considered occulters. We compare the behaviors of several, slightly different occulter transmittance profiles by evaluating the contrast performance of the high-contrast imaging testbed (HCIT) at the Jet Propulsion Laboratory (JPL). These occulters include a measured occulter, a standard Sinc(2) occulter, and several of its variations. We show that when an occulting mask has a parasitic phase, a modified Sinc(2) transmittance profile works much better than the standard Sinc(2) mask. We examine the impact of some fabrication errors of the occulter on the HCIT's contrast performance. We find through modeling and simulations that starlight suppression by a factor of more than 10(10) is achievable at least monochromatically on the HCIT with the occulting mask and the optics currently being used on the testbed. To the best of our knowledge, this is the first time that we investigate the behavior of a real (or fabricated) focal plane occulting mask in a high-contrast imaging system. We also briefly describe the approach used at JPL in fabricating a grayscale occulting mask and characterizing its transmittance and phase profiles.

  8. Optical scales, reticles, gratings, masks, and standards.

    PubMed

    Horne, D F

    1981-12-01

    Photofabrication techniques using positive photoresists, developed for the quantity production of theodolite circular scales, have been adapted to making master chrome masks for photoetching moire fringe radial diffraction gratings. Diamond stylus wear, or chipping of the diamond tip, on a precision surface measuring instrument is difficult to detect and can cause incorrect surface texture measurements. A stylus wear standard was developed, and fabrication problems were solved by the anisotropic etching of a silicon slice using a chrome mask and photoresist. An essential feature of this process was precise orientation of the mask with a crystal cleavage plane. Experience gained suggests the means for quantitative quality control of diamond tools used for micromachining.

  9. Masking water ice on small icy bodies

    NASA Astrophysics Data System (ADS)

    Brunetto, R.

    2011-10-01

    Additional clues on the surface composition of small icy bodies come from the laboratory study of cometary grains, such as some interplanetary dust particles collected in the Earth's stratosphere. These studies indicate the presence of refractory carbonaceous units that are usually sub-micron in size, i.e. smaller than the wavelength commonly used in remote sensing spectral observations of icy bodies. Based on this evidence, it has been suggested [2] that reddening of small icy bodies may be caused by submicron particles of organic material of pre-solar origin trapped in ice. According to this model, the amount of reddening varies with the concentration of organics to ice. To extend these results, we are developing a space weathering spectral model for small icy bodies that is compatible with laboratory measurements of collected cometary particles [3], and that takes into account the surface processing by solar and cosmic ions. Following the approach of Grundy [2], our model makes use of the Hapke scattering theory and of the Maxwell-Garnett effective medium theory to approximate the effect of carbon subwavelength inclusions. Preliminary results will be presented and discussed in view of their application to icy body surfaces. The conditions for the NIR spectral detection of water ice will be estimated. We will show that up to ~50% of water ice can be spectroscopically masked at 10% detection sensitivity due to the strong absorption of the sub-micron carbonaceous component, similarly to what previously found in the case of carbon-enriched crusts [4].

  10. When Bad Masks Turn Good

    NASA Astrophysics Data System (ADS)

    Abraham, Roberto G.

    In keeping with the spirit of a meeting on ‘masks,' this talk presents two short stories on the theme of dust. In the first, dust plays the familiar role of the evil obscurer, the enemy to bedefeated by the cunning observer in order to allow a key future technology (adaptive optics) to be exploited fully by heroic astronomers. In the second story, dust itself emerges as the improbable hero, in the form of a circumstellar debris disks. I will present evidence of a puzzling near-infrared excess in the continuum of high-redshift galaxies and will argue that the seemingly improbable origin of this IR excess is a population of young circumstellar disks formed around high-mass stars in distant galaxies. Assuming circumstellar disks extend down to lower masses,as they do in our own Galaxy, the excess emission presents us with an exciting opportunity to measure the formation rate of planetary systems in distant galaxies at cosmic epochs before our own solar system formed.

  11. Diplopia due to mask barotrauma.

    PubMed

    Latham, Emi; van Hoesen, Karen; Grover, Ian

    2011-11-01

    Scuba diving is a very popular and safe sport. Occasionally divers will suffer an injury from barotrauma, decompression sickness or an arterial gas embolism. The history and physical examination are important when determining the etiology of the injury and its subsequent treatment. This article will help readers identify key components of the history and physical examination in a patient to help differentiate between and injury caused by barotrauma or arterial gas embolism. This is a case of a diver that was initially felt to have an arterial gas embolism after scuba diving. After obtaining further history and performing a detailed physical exam it was determined that his diplopia was due to barotrauma from his mask. This was confirmed by an orbital computed tomography (CT) scan. Scuba diving is a very safe sport. When injuries occur it is important to obtain a careful history and physical examination to determine the exact cause of the injury because treatments vary according to the type of injury. In this case, the history and physical examination showed that the only neurologic sign the patient had was diplopia, which is not consistent with a diagnosis of arterial gas embolism. The CT scan helped with the diagnosis because it proved the patient had an orbital hematoma causing his proptosis and double vision. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Masked PDAMNA Film On Glass

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Polydiacetylenes are a unique class of highly conjugated organic polymers that are of interest for both electronic and photonic applications. Photodeposition from solutions is a novel process superior to those grown by conventional techniques. Evidence of this is seen when the films are viewed under a microscope; they exhibit small particles of solid polymer which form in the bulk solution, get transported by convection to the surface of the growing film, and become embedded. Also convection tends to cause the film thickness to be less uniform, and may even affect the molecular orientation of the films. The thrust of the research is to investigate in detail, both in 1-g and low-g, the effects of convection (and lack thereof) on this novel and interesting reaction. In this example, a portion of the substrate was blocked from exposure to the UV light by the mask, which was placed on the opposite side of the glass disk as the film, clearly demonstrating that photodeposition occurs only where the substrate is irradiated directly.

  13. High-radiance LDP source: clean, reliable, and stable EUV source for mask inspection

    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; Shirai, Takahiro; Nakamura, Kiyotada; Aoki, Kazuya; Kasama, Kunihiko

    2016-03-01

    High-throughput and -resolution actinic mask inspection tools are needed as EUVL begins to enter into volume production phase. To realize such inspection tools, a high-radiance EUV source is necessary. Ushio's laser-assisted discharge-produced plasma (LDP) source is able to meet industry's requirements in radiance, cleanliness, stability and reliability. Ushio's LDP source has shown the peak radiance at plasma of 180 W/mm2/sr and the area-averaged radiance in a 200-μm-diameter circle behind the debris mitigation system of 120 W/mm2/sr. A new version of the debris mitigation system is in testing phase. Its optical transmission was confirmed to be 73 %, which is 4 % lower than that of the previous version and therefore will be improved. Cleanliness of the system is evaluated by exposing Ru mirrors placed behind the debris mitigation system. Ru sputter rate was proven to be sufficiently low as 3~5 nm/Gpulse at 7 kHz, whereas frequency-dependent sputter rate was 1~3 nm/Gpulse at 5~9 kHz as previously reported. Sn deposition remained very low (< 0.05 nm) and did not grow over time. A new technique to suppress debris was tested and preliminary results were promising. Time-of-flight signal of fast ions was completely suppressed and Ru sputter rate of exposed mirrors at 3 kHz was approximately 1.3 nm/Gpulse, whereas the conventional mitigation system (new version) resulted in Ru sputter rate of 0.7 nm/Gpulse. This new technique also allows increasing the radiance efficiency by 30 %. Stability tests were done at several different discharge frequencies. Pulse energy stability was approximately 10 %. Dose energy stability dropped from approximately 2 % to 0.1 % when feedback control was activated. EUV emission position stability was studied at 3 kHz. Deviation of the plasma center of gravity was 6 μm, which is 3 % of plasma diameter and therefore considered to be negligible. Reliability tests were performed on both R and D and prototype machines and up to 200 hours of non

  14. Auditory masking of a 10 kHz tone with environmental, comodulated, and Gaussian noise in bottlenose dolphins (Tursiops truncatus).

    PubMed

    Trickey, Jennifer S; Branstetter, Brian K; Finneran, James J

    2010-12-01

    The pattern of auditory masking derived from Gaussian noise is often cited and used to predict the detrimental effects of masking noise on marine mammals. However, environmental noise (both anthropogenic and natural) may not always be Gaussian distributed. Some noise sources are highly structured with complex amplitude fluctuations that extend across frequency regions, which are often termed comodulated noise. Recent evidence with bottlenose dolphins using comodulated noise demonstrated a significant release from masking compared to Gaussian maskers of the same bandwidth and pressure spectral density level, a result known as comodulation masking release. The present study demonstrates a pattern of masking where both temporally fluctuating comodulated noise and environmental noise produce lower masked thresholds compared to Gaussian noise of the same spectral density level and bandwidth. Furthermore, a threshold reduction or "masking release" occurred when the environmental noise bandwidth increased beyond a critical band. These results provide further evidence that conventional models of auditory masking using Gaussian maskers (i.e., the power spectrum model) do not fully describe the masking effects that occur in realistic environments.

  15. An Improved Chaotic Masking Scheme via System-Alternating

    NASA Astrophysics Data System (ADS)

    Wang, Xing-Yuan; Xu, Bing; Ma, Yutian

    2013-10-01

    Aiming at the drawbacks of the chaotic masking scheme, this paper optimizes this conventional scheme by using improved state observer method and system-alternating method, proposes a new secure communication scheme which can improve these drawbacks of chaotic method: (1) Restriction that the power of useful signal must be smaller than that of chaotic signal. (2) Low security. In addition, the model of this whole communication system is constructed under the system simulation environment of Simulink.

  16. Implications of image plane line-edge roughness requirements on extreme ultraviolet mask specifications

    SciTech Connect

    Naulleau, P. P.; George, Simi A.

    2009-02-13

    Line-edge roughness (LER) and the related effect of contact size variation remain as significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. LER is typically viewed as a resist problem; however, recent simulation results have shown that the mask can indeed be an important contributor. Problems arise from both mask absorber LER as well as mask multilayer roughness leading to random phase variations in the reflected beam (see Fig. 1). The latter effect is especially important as higher coherence off-axis illumination conditions are used and defocus is considered. Here we describe these effect in detail and explore how they will impact EUV mask requirements for the 22-nm half-pitch node and beyond. Figure 2 shows modeling results for 22-nm lines printed in a 0.32-numerical aperture system with 100-nm defocus assuming a mask with 0.24-nm rms multilayer roughness and no absorber edge roughness (unlike the example in Fig. 1). The impact of the phase roughness on the printed line-edge roughness is clearly evident and demonstrates the basic problem with mask roughness. The more detailed modeling-based analysis to be presented will account for performance throughout the process window as well as non-stochastic resist effects. We note that the mean-field resist effect is important to consider because, in practice, the resist is the limiting resolution element in the system and therefore dominates the mask-error enhancement factor (MEEF). As is typically the case with projection-optic-induced MEEF, the resist-induced MEEF will lead to even tighter mask requirements. Note that we do not consider resist stochastic effects since the purpose of this study is isolate mask-induced sources of image-plane roughness.

  17. Thrifty metabolic programming in rats is induced by both maternal undernutrition and postnatal leptin treatment, but masked in the presence of both: implications for models of developmental programming.

    PubMed

    Ellis, Peter J I; Morris, Tiffany J; Skinner, Benjamin M; Sargent, Carole A; Vickers, Mark H; Gluckman, Peter D; Gilmour, Stewart; Affara, Nabeel A

    2014-01-21

    Maternal undernutrition leads to an increased risk of metabolic disorders in offspring including obesity and insulin resistance, thought to be due to a programmed thrifty phenotype which is inappropriate for a subsequent richer nutritional environment. In a rat model, both male and female offspring of undernourished mothers are programmed to become obese, however postnatal leptin treatment gives discordant results between males and females. Leptin treatment is able to rescue the adverse programming effects in the female offspring of undernourished mothers, but not in their male offspring. Additionally, in these rats, postnatal leptin treatment of offspring from normally-nourished mothers programmes their male offspring to develop obesity in later life, while there is no comparable effect in their female offspring. We show by microarray analysis of the female liver transcriptome that both maternal undernutrition and postnatal leptin treatment independently induce a similar thrifty transcriptional programme affecting carbohydrate metabolism, amino acid metabolism and oxidative stress genes. Paradoxically, however, the combination of both stimuli restores a more normal transcriptional environment. This demonstrates that "leptin reversal" is a global phenomenon affecting all genes involved in fetal programming by maternal undernourishment and leptin treatment. The thrifty transcriptional programme was associated with pro-inflammatory markers and downregulation of adaptive immune mediators, particularly MHC class I genes, suggesting a deficit in antigen presentation in these offspring. We propose a revised model of developmental programming reconciling the male and female observations, in which there are two competing programmes which collectively drive liver transcription. The first element is a thrifty metabolic phenotype induced by early life growth restriction independently of leptin levels. The second is a homeostatic set point calibrated in response to postnatal

  18. Masking properties of APD communication systems

    NASA Astrophysics Data System (ADS)

    Fernandez, J. G.; Larrondo, H. A.; Slavin, H. A.; Levin, D. G.; Hidalgo, R. M.; Rivera, R. R.

    2003-10-01

    In this paper, we explore the ability of wavelet multilevel analysis to unmask the information hidden in a chaotic mask. This digital filtering technique has been recently reported as particularly well suited for the detection of coherent structures. In a recent paper the capability of wavelets to unmask a message, in cases where a chaotic signal is just added to the information, has also been demonstrated. The case of an active passive decomposition scheme, where message is mixed with the chaotic signal, is studied here. A representative case employing Daubechies wavelets and a typical Rossler-oscillator-based communication system is reported. Using a time scaling parameter modifies the spectrum of the mask. The results show that wavelets are effective only in particular cases with poor masking. The fast Fourier transform analysis demonstrates that the spectrum of the chaotic mask shows no holes and then other digital filtering techniques such as Wiener filters or comb filters must also been disregarded.

  19. It's a Fine Season for Masks.

    ERIC Educational Resources Information Center

    Kennedy, Patricia

    1999-01-01

    Describes an art lesson, inspired by Giuseppe Arcimboldo's "Seasons" series, in which students construct masks representing one of the four seasons. Discusses the process and lists words and phrases associated with each season. (CMK)

  20. Inverse lithography using sparse mask representations

    NASA Astrophysics Data System (ADS)

    Ionescu, Radu C.; Hurley, Paul; Apostol, Stefan

    2015-03-01

    We present a novel optimisation algorithm for inverse lithography, based on optimization of the mask derivative, a domain inherently sparse, and for rectilinear polygons, invertible. The method is first developed assuming a point light source, and then extended to general incoherent sources. What results is a fast algorithm, producing manufacturable masks (the search space is constrained to rectilinear polygons), and flexible (specific constraints such as minimal line widths can be imposed). One inherent trick is to treat polygons as continuous entities, thus making aerial image calculation extremely fast and accurate. Requirements for mask manufacturability can be integrated in the optimization without too much added complexity. We also explain how to extend the scheme for phase-changing mask optimization.

  1. Masking of aluminum surface against anodizing

    NASA Technical Reports Server (NTRS)

    Crawford, G. B.; Thompson, R. E.

    1969-01-01

    Masking material and a thickening agent preserve limited unanodized areas when aluminum surfaces are anodized with chromic acid. For protection of large areas it combines well with a certain self-adhesive plastic tape.

  2. Correction of deflection under mask's own weight by bending mask technology

    NASA Astrophysics Data System (ADS)

    Yagami, Takashi; Kambayashi, Takashi; Azumi, Minako

    2016-10-01

    It is known that the photomask substrate deflects when the mask is set on the frame and the deflection is an obstacle to light exposure. In this study, we introduce "the bending mask" to cancel out the deflection. The surface of the bending mask has the height distribution in advance to cancel out the deflection, owing to Nikon's accurate polishing technology and Nikon's accurate measurement machine.

  3. Pixelated source and mask optimization for immersion lithography.

    PubMed

    Ma, Xu; Han, Chunying; Li, Yanqiu; Dong, Lisong; Arce, Gonzalo R

    2013-01-01

    Immersion lithography systems with hyper-numerical aperture (hyper-NA) (NA>1) have become indispensable in nanolithography for technology nodes of 45 nm and beyond. Source and mask optimization (SMO) has emerged as a key technique used to further improve the imaging performance of immersion lithography. Recently, a set of pixelated gradient-based SMO approaches were proposed under the scalar imaging models, which are inaccurate for hyper-NA settings. This paper focuses on developing pixelated gradient-based SMO algorithms based on a vector imaging model that is accurate for current immersion lithography. To achieve this goal, an integrative and analytic vector imaging model is first used to formulate the simultaneous SMO (SISMO) and sequential SMO (SESMO) frameworks. A gradient-based algorithm is then exploited to jointly optimize the source and mask. Subsequently, this paper studies and compares the performance of individual source optimization (SO), individual mask optimization (MO), SISMO, and SESMO. Finally, a hybrid SMO (HSMO) approach is proposed to take full advantage of SO, SISMO, and MO, consequently achieving superior performance.

  4. Applying Triple-Matrix Masking for Privacy Preserving Data Collection and Sharing in HIV Studies.

    PubMed

    Pei, Qinglin; Chen, Shigang; Xiao, Yao; Wu, Samuel S

    2016-01-01

    Many HIV research projects are plagued by the high missing rate of selfreported information during data collection. Also, due to the sensitive nature of the HIV research data, privacy protection is always a concern for data sharing in HIV studies. This paper applies a data masking approach, called triple-matrix masking [1], to the context of HIV research for ensuring privacy protection during the process of data collection and data sharing. Using a set of generated HIV patient data, we show step by step how the data are randomly transformed (masked) before leaving the patients' individual data collection device (which ensures that nobody sees the actual data) and how the masked data are further transformed by a masking service provider and a data collector. We demonstrate that the masked data retain statistical utility of the original data, yielding the exactly same inference results in the planned logistic regression on the effect of age on the adherence to antiretroviral therapy and in the Cox proportional hazard model for the age effect on time to viral load suppression. Privacy-preserving data collection method may help resolve the privacy protection issue in HIV research. The individual sensitive data can be completely hidden while the same inference results can still be obtained from the masked data, with the use of common statistical analysis methods.

  5. 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.

  6. Best focus shift mechanism for thick masks

    NASA Astrophysics Data System (ADS)

    Burkhardt, Martin; Raghunathan, Ananthan

    2015-03-01

    The best focus shift due to thick mask effects is well known, both in ArF, and more importantly in EUV, where the shorter wavelength is small compared to both mask openings and absorber height. While the effect is stronger in opaque features in clear field masks, the best focus shift is visible in dark field masks as well, and it becomes even more pronounced when scattering bars are added to non-dense features. This pattern dependent focus variation can be predicted in both exact EMF simulations and fast image calculations that are used for optical proximity correction (OPC). Even though this focus shift can be predicted and patterns can be corrected in OPC, we would like to understand the mechanism that causes this focus shift. This can help us understand if, in addition to best focus shift, the image quality is further deteriorated due to the thick mask effects. The best focus shift is found to be an interplay of the complex diffraction coefficient due to thick mask effects and the direction of the light that is incident on the mask, or coherence value σ. A change in focus adds a phase term to each of the complex diffraction coefficients, causing their rotation in a phasor diagram. Best focus is found when the phasors have an angle of 0 or 180 degrees to each other and depending on which diffracted orders are caught in the pupil and contribute to imaging. We investigate the effect of partial coherence, mask thickness, and assist feature placement on best focus shift. We observe a waveguide effect in the absorber gaps because of the reduced real index of refraction in the absorber layer, making vacuum the optically dense medium. We suggest ways to lessen the best focus shifts through assist feature placement or the use of alternative absorbers that are closer matched to the dielectric index of vacuum.

  7. Achromatic phase shifting focal plane masks

    NASA Astrophysics Data System (ADS)

    Newman, Kevin

    The search for life on other worlds is an exciting scientific endeavor that could change the way we perceive our place in the universe. Thousands of extrasolar planets have been discovered using indirect detection techniques. One of the most promising methods for discovering new exoplanets and searching for life is direct imaging with a coronagraph. Exoplanet coronagraphy of Earth-like planets is a challenging task, but we have developed many of the tools necessary to make it feasible. The Phase-Induced Amplitude Apodization (PIAA) Coronagraph is one of the highest-performing architectures for direct exoplanet imaging. With a complex phase-shifting focal plane mask, the PIAA Complex Mask Coronagraph (PIAACMC) can approach the theoretical performance limit for any direct detection technique. The architecture design is flexible enough to be applied to any arbitrary aperture shape, including segmented and obscured apertures. This is an important feature for compatibility with next-generation ground and space-based telescopes. PIAA and PIAACMC focal plane masks have been demonstrated in monochromatic light. An important next step for high-performance coronagraphy is the development of broadband phase-shifting focal plane masks. In this dissertation, we present an algorithm for designing the PIAA and PIAACMC focal plane masks to operate in broadband. We also demonstrate manufacturing of the focal plane masks, and show laboratory results. We use simulations to show the potential performance of the coronagraph system, and the use of wavefront control to correct for mask manufacturing errors. Given the laboratory results and simulations, we show new areas of exoplanet science that can potentially be explored using coronagraph technology. The main conclusion of this dissertation is that we now have the tools required to design and manufacture PIAA and PIAACMC achromatic focal plane masks. These tools can be applied to current and future telescope systems to enable new

  8. The neural processing of masked speech

    PubMed Central

    Scott, Sophie K; McGettigan, Carolyn

    2014-01-01

    Spoken language is rarely heard in silence, and a great deal of interest in psychoacoustics has focused on the ways that the perception of speech is affected by properties of masking noise. In this review we first briefly outline the neuroanatomy of speech perception. We then summarise the neurobiological aspects of the perception of masked speech, and investigate this as a function of masker type, masker level and task. PMID:23685149

  9. Thorough characterization of a EUV mask

    SciTech Connect

    Mizuno, H.; McIntyre, G.; Koay, C.-W.; Burkhardt, M.; He, L.; Hartley, J.; Johnson, C.; Raghunathan, S.; Goldberg, K.; Mochi, I.; La Fontaine, B.; Wood, O.

    2009-06-25

    We reported that we were successful in our 45nm technology node device demonstration in February 2008 and 22nm node technology node device patterning in February 2009 using ASML's Alpha Demo Tool (ADT). In order to insert extreme ultraviolet (EUV) lithography at the 15nm technology node and beyond, we have thoroughly characterized one EUV mask, a so-called NOVACD mask. In this paper, we report on three topics, The first topic is an analysis of line edge roughness (LER) using a mask Scanning Electron Microscope (SEM), an Atomic Force Microscope (AFM) and the Actinic Inspection Tool (AIT) to compare resist images printed with the ASML ADT. The results of the analysis show a good correlation between the mask AFM and the mask SEM measurements, However, the resist printing results for the isolated space patterns are slightly different. The cause ofthis discrepancy may be resist blur, image log slope and SEM image quality and so on. The second topic is an analysis of mask topography using an AFM and relative reflectivity of mirror and absorber surface using the AIT, The AFM data show 6 and 7 angstrom rms roughness for mirror and absorber, respectively. The reflectivity measurements show that the mirror reflects EUV light about 20 times higher than absorber. The last topic is an analysis of a 32nm technology node SRAM cell which includes a comparison of mask SEM image, AIT image, resist image and simulation results. The ADT images of the SRAM pattern were of high quality even though the mask patters were not corrected for OPC or any EUV-specific effects. Image simulation results were in good agreement with the printing results.

  10. Thrifty metabolic programming in rats is induced by both maternal undernutrition and postnatal leptin treatment, but masked in the presence of both: implications for models of developmental programming

    PubMed Central

    2014-01-01

    Background Maternal undernutrition leads to an increased risk of metabolic disorders in offspring including obesity and insulin resistance, thought to be due to a programmed thrifty phenotype which is inappropriate for a subsequent richer nutritional environment. In a rat model, both male and female offspring of undernourished mothers are programmed to become obese, however postnatal leptin treatment gives discordant results between males and females. Leptin treatment is able to rescue the adverse programming effects in the female offspring of undernourished mothers, but not in their male offspring. Additionally, in these rats, postnatal leptin treatment of offspring from normally-nourished mothers programmes their male offspring to develop obesity in later life, while there is no comparable effect in their female offspring. Results We show by microarray analysis of the female liver transcriptome that both maternal undernutrition and postnatal leptin treatment independently induce a similar thrifty transcriptional programme affecting carbohydrate metabolism, amino acid metabolism and oxidative stress genes. Paradoxically, however, the combination of both stimuli restores a more normal transcriptional environment. This demonstrates that “leptin reversal” is a global phenomenon affecting all genes involved in fetal programming by maternal undernourishment and leptin treatment. The thrifty transcriptional programme was associated with pro-inflammatory markers and downregulation of adaptive immune mediators, particularly MHC class I genes, suggesting a deficit in antigen presentation in these offspring. Conclusions We propose a revised model of developmental programming reconciling the male and female observations, in which there are two competing programmes which collectively drive liver transcription. The first element is a thrifty metabolic phenotype induced by early life growth restriction independently of leptin levels. The second is a homeostatic set point

  11. No masking between test and mask components in perceptually different depth planes.

    PubMed

    Hibbeler, Patrick J; Olzak, Lynn A

    2011-01-01

    2-D cues to perceived depth organization have been used to segregate test and mask stimulus components in a discrimination task. Observers made either spatial-frequency or orientation judgments on a rectangular test component by itself or in the presence of constant rectangular masks. There were two basic masking conditions: same-plane or different-plane. In the same-plane conditions, the test components and masks are perceived as existing in the same depth plane. In the different-plane conditions, the test and mask components are perceived to exist in different depth planes. The perception of different depth planes was achieved by using perceived occlusion, which could place either component closer or further from the observer. The results suggest that when test and mask components are separated into different depth planes they no longer influence one another. This effect could be observed in either depth organization, test components in front of the masks or mask components in front of the test. These results indicate that the figure-ground organization of components is not important. Only the designation as existing in the same or different depth planes affects whether or not a mask is effective.

  12. Supreme Laryngeal Mask Airway versus Face Mask during Neonatal Resuscitation: A Randomized Controlled Trial.

    PubMed

    Trevisanuto, Daniele; Cavallin, Francesco; Nguyen, Loi Ngoc; Nguyen, Tien Viet; Tran, Linh Dieu; Tran, Chien Dinh; Doglioni, Nicoletta; Micaglio, Massimo; Moccia, Luciano

    2015-08-01

    To assess the effectiveness of supreme laryngeal mask airway (SLMA) over face mask ventilation for preventing need for endotracheal intubation at birth. We report a prospective, randomized, parallel 1:1, unblinded, controlled trial. After a short-term educational intervention on SLMA use, infants ≥34-week gestation and/or expected birth weight ≥1500 g requiring positive pressure ventilation (PPV) at birth were randomized to resuscitation by SLMA or face mask. The primary outcome was the success rate of the resuscitation devices (SLMA or face mask) defined as the achievement of an effective PPV preventing the need for endotracheal intubation. We enrolled 142 patients (71 in SLMA and 71 in face mask group, respectively). Successful resuscitation rate was significantly higher with the SLMA compared with face mask ventilation (91.5% vs 78.9%; P = .03). Apgar score at 5 minutes was significantly higher in SLMA than in face mask group (P = .02). Neonatal intensive care unit admission rate was significantly lower in SLMA than in face mask group (P = .02). No complications related to the procedure occurred. In newborns with gestational age ≥34 weeks and/or expected birth weight ≥1500 g needing PPV at birth, the SLMA is more effective than face mask to prevent endotracheal intubation. The SLMA is effective in clinical practice after a short-term educational intervention. Registered with ClinicalTrials.gov: NCT01963936. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. VSP wave separation by adaptive masking filters

    NASA Astrophysics Data System (ADS)

    Rao, Ying; Wang, Yanghua

    2016-06-01

    In vertical seismic profiling (VSP) data processing, the first step might be to separate the down-going wavefield from the up-going wavefield. When using a masking filter for VSP wave separation, there are difficulties associated with two termination ends of the up-going waves. A critical challenge is how the masking filter can restore the energy tails, the edge effect associated with these terminations uniquely exist in VSP data. An effective strategy is to implement masking filters in both τ-p and f-k domain sequentially. Meanwhile it uses a median filter, producing a clean but smooth version of the down-going wavefield, used as a reference data set for designing the masking filter. The masking filter is implemented adaptively and iteratively, gradually restoring the energy tails cut-out by any surgical mute. While the τ-p and the f-k domain masking filters target different depth ranges of VSP, this combination strategy can accurately perform in wave separation from field VSP data.

  14. Laser mask repair system LM700A

    NASA Astrophysics Data System (ADS)

    Ueda, Atsushi; Yoshino, Yoichi; Morishige, Yukio; Watanabe, Syuichi; Kyusho, Yukio; Haneda, Tsutoma; Ohmiya, Makoto

    2001-09-01

    High throughput laser mask repair system satisfying the accuracy demanded for 0.5micrometers pattern rule reticles has been newly developed. The named Laser Mask Repair LM700A has the following versatile features: *Opaque defect repair capability of 0.5micrometers L&S patterns with high repair accuracy of 45nm (3(sigma) ) *Low Quartz damage and high transmission at the repair site, especially for MoSi KrF-HT mask, and applicable to MoSi ArF-HT mask, by newly developed pico-second solid state UV pulse laser *0.1micrometers defect detectability by high resolution UV Optics *Through pellicle repair capability by newly developed long working distance UV objective lens *Auto-edge positioning function for various patterns By utilizing a pico-second UV pulse laser, very high quality laser zapping can be obtained. This paper presents the configuration and the evaluated results for mask repair performance in MoSi KrF-HT and ArF-HT masks.

  15. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Mask work fees. 211.3 Section... AND PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask works...

  16. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Mask work fees. 211.3 Section... PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask works. (b) Section...

  17. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Mask work fees. 211.3 Section... PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask works. (b) Section...

  18. 21 CFR 868.5560 - Gas mask head strap.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gas mask head strap. 868.5560 Section 868.5560...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5560 Gas mask head strap. (a) Identification. A gas mask head strap is a device used to hold an anesthetic gas mask in position on a patient's...

  19. 21 CFR 868.5560 - Gas mask head strap.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gas mask head strap. 868.5560 Section 868.5560...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5560 Gas mask head strap. (a) Identification. A gas mask head strap is a device used to hold an anesthetic gas mask in position on a patient's...

  20. 21 CFR 868.5560 - Gas mask head strap.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gas mask head strap. 868.5560 Section 868.5560...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5560 Gas mask head strap. (a) Identification. A gas mask head strap is a device used to hold an anesthetic gas mask in position on a patient's...