Matching OPC and masks on 300-mm lithography tools utilizing variable illumination settings

NASA Astrophysics Data System (ADS)

Palitzsch, Katrin; Kubis, Michael; Schroeder, Uwe P.; Schumacher, Karl; Frangen, Andreas

2004-05-01

CD control is crucial to maximize product yields on 300mm wafers. This is particularly true for DRAM frontend lithography layers, like gate level, and deep trench (capacitor) level. In the DRAM process, large areas of the chip are taken up by array structures, which are difficult to structure due to aggressive pitch requirements. Consequently, the lithography process is centered such that the array structures are printed on target. Optical proximity correction is applied to print gate level structures in the periphery circuitry on target. Only slight differences of the different Zernike terms can cause rather large variations of the proximity curves, resulting in a difference of isolated and semi-isolated lines printed on different tools. If the deviations are too large, tool specific OPC is needed. The same is true for deep trench level, where the length to width ratio of elongated contact-like structures is an important parameter to adjust the electrical properties of the chip. Again, masks with specific biases for tools with different Zernikes are needed to optimize product yield. Additionally, mask making contributes to the CD variation of the process. Theoretically, the CD deviation caused by an off-centered mask process can easily eat up the majority of the CD budget of a lithography process. In practice, masks are very often distributed intelligently among production tools, such that lens and mask effects cancel each other. However, only dose adjusting and mask allocation may still result in a high CD variation with large systematical contributions. By adjusting the illumination settings, we have successfully implemented a method to reduce CD variation on our advanced processes. Especially inner and outer sigma for annular illumination, and the numerical aperture, can be optimized to match mask and stepper properties. This process will be shown to overcome slight lens and mask differences effectively. The effects on lithography process windows have to be considered, nonetheless.

Future reticle demand and next-generation lithography technologies

NASA Astrophysics Data System (ADS)

Behringer, Uwe F. W.; Ehrlich, Christian; Fortange, Olaf

1999-04-01

Mask technology has often been considered an enabling for semiconductor fabrication. But today photomasks have evolved to a bottle neck in the every increasing integration process of semiconductor circuits. Regarding to the 1997 SIA roadmap there are very stringent requirements for mask making. Even with the momentary weak Asian market the worldwide demand for reticles will continue to grow. The anticipation of larger reticles has been discussed over years. What ever the reason for the need of larger reticles, the move to the 230 mm X 230 mm reticle size will provide size will provide unique challenges to both the mask equipment manufacturers and mask fabricator. Next Generation Lithography together with their mask techniques are in development and try to come into the market.

Clean induced feature CD shift of EUV mask

NASA Astrophysics Data System (ADS)

Nesládek, Pavel; Schedel, Thorsten; Bender, Markus

2016-05-01

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

Statistical mechanics of image processing by digital halftoning

NASA Astrophysics Data System (ADS)

Inoue, Jun-Ichi; Norimatsu, Wataru; Saika, Yohei; Okada, Masato

2009-03-01

We consider the problem of digital halftoning (DH). The DH is an image processing representing each grayscale in images in terms of black and white dots, and it is achieved by making use of the threshold dither mask, namely, each pixel is determined as black if the grayscale pixel is greater than or equal to the mask value and as white vice versa. To determine the mask for a given grayscale image, we assume that human-eyes might recognize the BW dots as the corresponding grayscale by linear filters. Then, the Hamiltonian is constructed as a distance between the original and recognized images which is written in terms of the mask. Finding the ground state of the Hamiltonian via deterministic annealing, we obtain the optimal mask and the BW dots simultaneously. From the spectrum analysis, we find that the BW dots are desirable from the view point of human-eyes modulation properties. We also show that the lower bound of the mean square error for the inverse process of the DH is minimized on the Nishimori line which is well-known in the research field of spin glasses.

Mask data processing in the era of multibeam writers

NASA Astrophysics Data System (ADS)

Abboud, Frank E.; Asturias, Michael; Chandramouli, Maesh; Tezuka, Yoshihiro

2014-10-01

Mask writers' architectures have evolved through the years in response to ever tightening requirements for better resolution, tighter feature placement, improved CD control, and tolerable write time. The unprecedented extension of optical lithography and the myriad of Resolution Enhancement Techniques have tasked current mask writers with ever increasing shot count and higher dose, and therefore, increasing write time. Once again, we see the need for a transition to a new type of mask writer based on massively parallel architecture. These platforms offer a step function improvement in both dose and the ability to process massive amounts of data. The higher dose and almost unlimited appetite for edge corrections open new windows of opportunity to further push the envelope. These architectures are also naturally capable of producing curvilinear shapes, making the need to approximate a curve with multiple Manhattan shapes unnecessary.

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

NASA Astrophysics Data System (ADS)

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

1999-12-01

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

Patterned mask inspection technology with Projection Electron Microscope (PEM) technique for 11 nm half-pitch (hp) generation EUV masks

NASA Astrophysics Data System (ADS)

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

2015-07-01

High-sensitivity EUV mask pattern defect detection is one of the major issues in order to realize the device fabrication by using the EUV lithography. We have already designed a novel Projection Electron Microscope (PEM) optics that has been integrated into a new inspection system named EBEYE-V30 ("Model EBEYE" is an EBARA's model code), and which seems to be quite promising for 16 nm hp generation EUVL Patterned mask Inspection (PI). Defect inspection sensitivity was evaluated by capturing an electron image generated at the mask by focusing onto an image sensor. The progress of the novel PEM optics performance is not only about making an image sensor with higher resolution but also about doing a better image processing to enhance the defect signal. In this paper, we describe the experimental results of EUV patterned mask inspection using the above-mentioned system. The performance of the system is measured in terms of defect detectability for 11 nm hp generation EUV mask. To improve the inspection throughput for 11 nm hp generation defect detection, it would require a data processing rate of greater than 1.5 Giga- Pixel-Per-Second (GPPS) that would realize less than eight hours of inspection time including the step-and-scan motion associated with the process. The aims of the development program are to attain a higher throughput, and enhance the defect detection sensitivity by using an adequate pixel size with sophisticated image processing resulting in a higher processing rate.

Fast mask writers: technology options and considerations

NASA Astrophysics Data System (ADS)

Litt, Lloyd C.; Groves, Timothy; Hughes, Greg

2011-04-01

The semiconductor industry is under constant pressure to reduce production costs even as the complexity of technology increases. Lithography represents the most expensive process due to its high capital equipment costs and the implementation of low-k1 lithographic processes, which have added to the complexity of making masks because of 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 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 funding on the order of 50M to 90M for 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 poses a high risk for an individual supplier. The structure of the mask fabrication marketplace separates the mask writer equipment customer (the mask supplier) from the final customer (wafer manufacturer) that will be most effected by the increase in mask cost that will result if a high speed mask writer is not available. Since no individual company will likely risk entering this market, some type of industry-wide funding model will be needed.

Development of a data management front end for use with a LANDSAT based information system. [assessing gypsy moth defoliation damage in Pennsylvania

NASA Technical Reports Server (NTRS)

Turner, B. J. (Principal Investigator)

1982-01-01

A user friendly front end was constructed to facilitate access to the LANDSAT mosaic data base supplied by JPL and to process both LANDSAT and ancillary data. Archieval and retrieval techniques were developed to efficiently handle this data base and make it compatible with requirements of the Pennsylvania Bureau of Forestry. Procedures are ready for: (1) forming the forest/nonforest mask in ORSER compressed map format using GSFC-supplied classification procedures; (2) registering data from a new scene (defoliated) to the mask (which may involve mosaicking if the area encompasses two LANDSAT scenes; (3) producing a masked new data set using the MASK program; (4) analyzing this data set to produce a map showing degrees of defoliation, output on the Versatec plotter; and (5) producing color composite maps by a diazo-type process.

Masking interrupts figure-ground signals in V1.

PubMed

Lamme, Victor A F; Zipser, Karl; Spekreijse, Henk

2002-10-01

In a backward masking paradigm, a target stimulus is rapidly (<100 msec) followed by a second stimulus. This typically results in a dramatic decrease in the visibility of the target stimulus. It has been shown that masking reduces responses in V1. It is not known, however, which process in V1 is affected by the mask. In the past, we have shown that in V1, modulations of neural activity that are specifically related to figure-ground segregation can be recorded. Here, we recorded from awake macaque monkeys, engaged in a task where they had to detect figures from background in a pattern backward masking paradigm. We show that the V1 figure-ground signals are selectively and fully suppressed at target-mask intervals that psychophysically result in the target being invisible. Initial response transients, signalling the features that make up the scene, are not affected. As figure-ground modulations depend on feedback from extrastriate areas, these results suggest that masking selectively interrupts the recurrent interactions between V1 and higher visual areas.

Anticipating and controlling mask costs within EDA physical design

NASA Astrophysics Data System (ADS)

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

2003-08-01

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

1D design style implications for mask making and CEBL

NASA Astrophysics Data System (ADS)

Smayling, Michael C.

2013-09-01

At advanced nodes, CMOS logic is being designed in a highly regular design style because of the resolution limitations of optical lithography equipment. Logic and memory layouts using 1D Gridded Design Rules (GDR) have been demonstrated to nodes beyond 12nm.[1-4] Smaller nodes will require the same regular layout style but with multiple patterning for critical layers. One of the significant advantages of 1D GDR is the ease of splitting layouts into lines and cuts. A lines and cuts approach has been used to achieve good pattern fidelity and process margin to below 12nm.[4] Line scaling with excellent line-edge roughness (LER) has been demonstrated with self-aligned spacer processing.[5] This change in design style has important implications for mask making: • The complexity of the masks will be greatly reduced from what would be required for 2D designs with very complex OPC or inverse lithography corrections. • The number of masks will initially increase, as for conventional multiple patterning. But in the case of 1D design, there are future options for mask count reduction. • The line masks will remain simple, with little or no OPC, at pitches (1x) above 80nm. This provides an excellent opportunity for continual improvement of line CD and LER. The line pattern will be processed through a self-aligned pitch division sequence to divide pitch by 2 or by 4. • The cut masks can be done with "simple OPC" as demonstrated to beyond 12nm.[6] Multiple simple cut masks may be required at advanced nodes. "Coloring" has been demonstrated to below 12nm for two colors and to 8nm for three colors. • Cut/hole masks will eventually be replaced by e-beam direct write using complementary e-beam lithography (CEBL).[7-11] This transition is gated by the availability of multiple column e-beam systems with throughput adequate for high- volume manufacturing. A brief description of 1D and 2D design styles will be presented, followed by examples of 1D layouts. Mask complexity for 1D layouts patterned directly will be compared to mask complexity for lines and cuts at nodes larger than 20nm. No such comparison is possible below 20nm since single-patterning does not work below ~80nm pitch using optical exposure tools. Also discussed will be recently published wafer results for line patterns with pitch division by-2 and by-4 at sub-12nm nodes, plus examples of post-etch results for 1D patterns done with cut masks and compared to cuts exposed by a single-column e-beam direct write system.

New method of 2-dimensional metrology using mask contouring

NASA Astrophysics Data System (ADS)

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

2008-10-01

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

Integration of mask and silicon metrology in DFM

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Sugiyama, Akiyuki; Toyoda, Yasutaka

2009-03-01

We have developed a highly integrated method of mask and silicon metrology. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. We have inspected the high accuracy, stability and reproducibility in the experiments of integration. The accuracy is comparable with that of the mask and silicon CD-SEM metrology. In this report, we introduce the experimental results and the application. As shrinkage of design rule for semiconductor device advances, OPC (Optical Proximity Correction) goes aggressively dense in RET (Resolution Enhancement Technology). However, from the view point of DFM (Design for Manufacturability), the cost of data process for advanced MDP (Mask Data Preparation) and mask producing is a problem. Such trade-off between RET and mask producing is a big issue in semiconductor market especially in mask business. Seeing silicon device production process, information sharing is not completely organized between design section and production section. Design data created with OPC and MDP should be linked to process control on production. But design data and process control data are optimized independently. Thus, we provided a solution of DFM: advanced integration of mask metrology and silicon metrology. The system we propose here is composed of followings. 1) Design based recipe creation: Specify patterns on the design data for metrology. This step is fully automated since they are interfaced with hot spot coordinate information detected by various verification methods. 2) Design based image acquisition: Acquire the images of mask and silicon automatically by a recipe based on the pattern design of CD-SEM.It is a robust automated step because a wide range of design data is used for the image acquisition. 3) Contour profiling and GDS data generation: An image profiling process is applied to the acquired image based on the profiling method of the field proven CD metrology algorithm. The detected edges are then converted to GDSII format, which is a standard format for a design data, and utilized for various DFM systems such as simulation. Namely, by integrating pattern shapes of mask and silicon formed during a manufacturing process into GDSII format, it makes it possible to bridge highly accurate pattern profile information over to the design field of various EDA systems. These are fully integrated into design data and automated. Bi-directional cross probing between mask data and process control data is allowed by linking them. This method is a solution for total optimization that covers Design, MDP, mask production and silicon device producing. This method therefore is regarded as a strategic DFM approach in the semiconductor metrology.

Challenges in process marginality for advanced technology nodes and tackling its contributors

NASA Astrophysics Data System (ADS)

Narayana Samy, Aravind; Schiwon, Roberto; Seltmann, Rolf; Kahlenberg, Frank; Katakamsetty, Ushasree

2013-10-01

Process margin is getting critical in the present node shrinkage scenario due to the physical limits reached (Rayleigh's criterion) using ArF lithography tools. K1 is used to its best for better resolution and to enhance the process margin (28nm metal patterning k1=0.31). In this paper, we would like to give an overview of various contributors in the advanced technology nodes which limit the process margins and how the challenges have been tackled in a modern foundry model. Advanced OPC algorithms are used to make the design content at the mask optimum for patterning. However, as we work at the physical limit, critical features (Hot-spots) are very susceptible to litho process variations. Furthermore, etch can have a significant impact as well. Pattern that still looks healthy at litho can fail due to etch interactions. This makes the traditional 2D contour output from ORC tools not able to predict accurately all defects and hence not able to fully correct it in the early mask tapeout phase. The above makes a huge difference in the fast ramp-up and high yield in a competitive foundry market. We will explain in this paper how the early introduction of 3D resist model based simulation of resist profiles (resist top-loss, bottom bridging, top-rounding, etc.,) helped in our prediction and correction of hot-spots in the early 28nm process development phase. The paper also discusses about the other overall process window reduction contributors due to mask 3D effects, wafer topography (focus shifts/variations) and how this has been addressed with different simulation efforts in a fast and timely manner.

Speed Isn't Everything: Complex Processing Speed Measures Mask Individual Differences and Developmental Changes in Executive Control

ERIC Educational Resources Information Center

Cepeda, Nicholas J.; Blackwell, Katharine A.; Munakata, Yuko

2013-01-01

The rate at which people process information appears to influence many aspects of cognition across the lifespan. However, many commonly accepted measures of "processing speed" may require goal maintenance, manipulation of information in working memory, and decision-making, blurring the distinction between processing speed and executive…

My Other Half Manifested in Mask-Making

ERIC Educational Resources Information Center

Abel, Xanthippi

2010-01-01

Every fall season, each grade level of Rowland Hall St. Mark's Lower School in Salt Lake City, Utah, completes a mask-making project to be featured in a schoolwide parade. This sparked an opportunity to incorporate the fourth-grade unit of realistic and observational drawing with mask making. In this article, the author describes how her students…

The edge of awareness: Mask spatial density, but not color, determines optimal temporal frequency for continuous flash suppression.

PubMed

Drewes, Jan; Zhu, Weina; Melcher, David

2018-01-01

The study of how visual processing functions in the absence of visual awareness has become a major research interest in the vision-science community. One of the main sources of evidence that stimuli that do not reach conscious awareness-and are thus "invisible"-are still processed to some degree by the visual system comes from studies using continuous flash suppression (CFS). Why and how CFS works may provide more general insight into how stimuli access awareness. As spatial and temporal properties of stimuli are major determinants of visual perception, we hypothesized that these properties of the CFS masks would be of significant importance to the achieved suppression depth. In previous studies however, the spatial and temporal properties of the masks themselves have received little study, and masking parameters vary widely across studies, making a metacomparison difficult. To investigate the factors that determine the effectiveness of CFS, we varied both the temporal frequency and the spatial density of Mondrian-style masks. We consistently found the longest suppression duration for a mask temporal frequency of around 6 Hz. In trials using masks with reduced spatial density, suppression was weaker and frequency tuning was less precise. In contrast, removing color reduced mask effectiveness but did not change the pattern of suppression strength as a function of frequency. Overall, this pattern of results stresses the importance of CFS mask parameters and is consistent with the idea that CFS works by disrupting the spatiotemporal mechanisms that underlie conscious access to visual input.

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.

Video encryption using chaotic masks in joint transform correlator

NASA Astrophysics Data System (ADS)

Saini, Nirmala; Sinha, Aloka

2015-03-01

A real-time optical video encryption technique using a chaotic map has been reported. In the proposed technique, each frame of video is encrypted using two different chaotic random phase masks in the joint transform correlator architecture. The different chaotic random phase masks can be obtained either by using different iteration levels or by using different seed values of the chaotic map. The use of different chaotic random phase masks makes the decryption process very complex for an unauthorized person. Optical, as well as digital, methods can be used for video encryption but the decryption is possible only digitally. To further enhance the security of the system, the key parameters of the chaotic map are encoded using RSA (Rivest-Shamir-Adleman) public key encryption. Numerical simulations are carried out to validate the proposed technique.

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 holds true. There is a need to be flexible enough on unrepairable defect at early stage but also a need for efficient risk management system on mask defect waivers. Mask defects are often waived in low design criticality area in favor of scrapping the mask and delaying the mask and wafer schedule. Xilinx's involvement in mask manufacturing has contributed significantly to our success in past many nodes and will continue.

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

NASA Astrophysics Data System (ADS)

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

2016-10-01

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

Layout optimization of DRAM cells using rigorous simulation model for NTD

NASA Astrophysics Data System (ADS)

Jeon, Jinhyuck; Kim, Shinyoung; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Kuechler, Bernd; Zimmermann, Rainer; Muelders, Thomas; Klostermann, Ulrich; Schmoeller, Thomas; Do, Mun-hoe; Choi, Jung-Hoe

2014-03-01

DRAM chip space is mainly determined by the size of the memory cell array patterns which consist of periodic memory cell features and edges of the periodic array. Resolution Enhancement Techniques (RET) are used to optimize the periodic pattern process performance. Computational Lithography such as source mask optimization (SMO) to find the optimal off axis illumination and optical proximity correction (OPC) combined with model based SRAF placement are applied to print patterns on target. For 20nm Memory Cell optimization we see challenges that demand additional tool competence for layout optimization. The first challenge is a memory core pattern of brick-wall type with a k1 of 0.28, so it allows only two spectral beams to interfere. We will show how to analytically derive the only valid geometrically limited source. Another consequence of two-beam interference limitation is a "super stable" core pattern, with the advantage of high depth of focus (DoF) but also low sensitivity to proximity corrections or changes of contact aspect ratio. This makes an array edge correction very difficult. The edge can be the most critical pattern since it forms the transition from the very stable regime of periodic patterns to non-periodic periphery, so it combines the most critical pitch and highest susceptibility to defocus. Above challenge makes the layout correction to a complex optimization task demanding a layout optimization that finds a solution with optimal process stability taking into account DoF, exposure dose latitude (EL), mask error enhancement factor (MEEF) and mask manufacturability constraints. This can only be achieved by simultaneously considering all criteria while placing and sizing SRAFs and main mask features. The second challenge is the use of a negative tone development (NTD) type resist, which has a strong resist effect and is difficult to characterize experimentally due to negative resist profile taper angles that perturb CD at bottom characterization by scanning electron microscope (SEM) measurements. High resist impact and difficult model data acquisition demand for a simulation model that hat is capable of extrapolating reliably beyond its calibration dataset. We use rigorous simulation models to provide that predictive performance. We have discussed the need of a rigorous mask optimization process for DRAM contact cell layout yielding mask layouts that are optimal in process performance, mask manufacturability and accuracy. In this paper, we have shown the step by step process from analytical illumination source derivation, a NTD and application tailored model calibration to layout optimization such as OPC and SRAF placement. Finally the work has been verified with simulation and experimental results on wafer.

A tunable sub-100 nm silicon nanopore array with an AAO membrane mask: reducing unwanted surface etching by introducing a PMMA interlayer

NASA Astrophysics Data System (ADS)

Lim, Namsoo; Pak, Yusin; Kim, Jin Tae; Hwang, Youngkyu; Lee, Ryeri; Kumaresan, Yogeenth; Myoung, Nosoung; Ko, Heung Cho; Jung, Gun Young

2015-08-01

Highly ordered silicon (Si) nanopores with a tunable sub-100 nm diameter were fabricated by a CF4 plasma etching process using an anodic aluminum oxide (AAO) membrane as an etching mask. To enhance the conformal contact of the AAO membrane mask to the underlying Si substrate, poly(methyl methacrylate) (PMMA) was spin-coated on top of the Si substrate prior to the transfer of the AAO membrane. The AAO membrane mask was fabricated by two-step anodization and subsequent removal of the aluminum support and the barrier layer, which was then transferred to the PMMA-coated Si substrate. Contact printing was performed on the sample with a pressure of 50 psi and a temperature of 120 °C to make a conformal contact of the AAO membrane mask to the Si substrate. The CF4 plasma etching was conducted to transfer nanopores onto the Si substrate through the PMMA interlayer. The introduced PMMA interlayer prevented unwanted surface etching of the Si substrate by eliminating the etching ions and radicals bouncing at the gap between the mask and the substrate, resulting in a smooth Si nanopore array.Highly ordered silicon (Si) nanopores with a tunable sub-100 nm diameter were fabricated by a CF4 plasma etching process using an anodic aluminum oxide (AAO) membrane as an etching mask. To enhance the conformal contact of the AAO membrane mask to the underlying Si substrate, poly(methyl methacrylate) (PMMA) was spin-coated on top of the Si substrate prior to the transfer of the AAO membrane. The AAO membrane mask was fabricated by two-step anodization and subsequent removal of the aluminum support and the barrier layer, which was then transferred to the PMMA-coated Si substrate. Contact printing was performed on the sample with a pressure of 50 psi and a temperature of 120 °C to make a conformal contact of the AAO membrane mask to the Si substrate. The CF4 plasma etching was conducted to transfer nanopores onto the Si substrate through the PMMA interlayer. The introduced PMMA interlayer prevented unwanted surface etching of the Si substrate by eliminating the etching ions and radicals bouncing at the gap between the mask and the substrate, resulting in a smooth Si nanopore array. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02786a

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.

Scanner qualification with IntenCD based reticle error correction

NASA Astrophysics Data System (ADS)

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

2010-03-01

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

Mask Making: The Use of the Expressive Arts in Leadership Development.

ERIC Educational Resources Information Center

Jones, Angela Thomas

1992-01-01

Outdoor educators in training engaged in a mask-making activity involving partners. One person made the mask and the other provided his or her face as the mold. The anxiety-provoking experience invited an intimate exchange between partners around issues of intimacy, trust, and compassion. (KS)

Status of EUVL mask development in Europe (Invited Paper)

NASA Astrophysics Data System (ADS)

Peters, Jan H.

2005-06-01

EUV lithography is the prime candidate for the next generation lithography technology after 193 nm immersion lithography. The commercial onset for this technology is expected for the 45 nm half-pitch technology or below. Several European and national projects and quite a large number of companies and research institutions in Europe work on various aspects of the technological challenges to make EUV a commercially viable technology in the not so far future. Here the development of EUV sources, the development of an EUV exposure tools, metrology tools dedicated for characterization of mask, the production of EUV mask blanks and the mask structuring itself are the key areas in which major activities can be found. In this talk we will primarily focus on those activities, which are related to establish an EUV mask supply chain with all its ingredients from substrate production, polishing, deposition of EUV layers, blank characterization, mask patterning process and the consecutive metrology and defect inspection as well as shipping and handling from blank supply to usage in the wafer fab. The EUV mask related projects on the national level are primarily supported by the French Ministry of Economics and Finance (MinEFi) and the German Ministry of Education and Research (BMBF).

Implementation of assist features in EUV lithography

NASA Astrophysics Data System (ADS)

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

2015-03-01

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

Image processing and pattern recognition with CVIPtools MATLAB toolbox: automatic creation of masks for veterinary thermographic images

NASA Astrophysics Data System (ADS)

Mishra, Deependra K.; Umbaugh, Scott E.; Lama, Norsang; Dahal, Rohini; Marino, Dominic J.; Sackman, Joseph

2016-09-01

CVIPtools is a software package for the exploration of computer vision and image processing developed in the Computer Vision and Image Processing Laboratory at Southern Illinois University Edwardsville. CVIPtools is available in three variants - a) CVIPtools Graphical User Interface, b) CVIPtools C library and c) CVIPtools MATLAB toolbox, which makes it accessible to a variety of different users. It offers students, faculty, researchers and any user a free and easy way to explore computer vision and image processing techniques. Many functions have been implemented and are updated on a regular basis, the library has reached a level of sophistication that makes it suitable for both educational and research purposes. In this paper, the detail list of the functions available in the CVIPtools MATLAB toolbox are presented and how these functions can be used in image analysis and computer vision applications. The CVIPtools MATLAB toolbox allows the user to gain practical experience to better understand underlying theoretical problems in image processing and pattern recognition. As an example application, the algorithm for the automatic creation of masks for veterinary thermographic images is presented.

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

NASA Astrophysics Data System (ADS)

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

2006-06-01

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

Digital chaos-masked optical encryption scheme enhanced by two-dimensional key space

NASA Astrophysics Data System (ADS)

Liu, Ling; Xiao, Shilin; Zhang, Lu; Bi, Meihua; Zhang, Yunhao; Fang, Jiafei; Hu, Weisheng

2017-09-01

A digital chaos-masked optical encryption scheme is proposed and demonstrated. The transmitted signal is completely masked by interference chaotic noise in both bandwidth and amplitude with analog method via dual-drive Mach-Zehnder modulator (DDMZM), making the encrypted signal analog, noise-like and unrecoverable by post-processing techniques. The decryption process requires precise matches of both the amplitude and phase between the cancellation and interference chaotic noises, which provide a large two-dimensional key space with the help of optical interference cancellation technology. For 10-Gb/s 16-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal over the maximum transmission distance of 80 km without dispersion compensation or inline amplifier, the tolerable mismatch ranges of amplitude and phase/delay at the forward error correction (FEC) threshold of 3.8×10-3 are 0.44 dB and 0.08 ns respectively.

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.

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

NASA Astrophysics Data System (ADS)

Shoji, Masahiro; Inoue, Tadao; Yamabe, Masaki

2010-05-01

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

X-ray mask and method for making

DOEpatents

Morales, Alfredo M.

2004-10-26

The present invention describes a method for fabricating an x-ray mask tool which is a contact lithographic mask which can provide an x-ray exposure dose which is adjustable from point-to-point. The tool is useful in the preparation of LIGA plating molds made from PMMA, or similar materials. In particular the tool is useful for providing an ability to apply a graded, or "stepped" x-ray exposure dose across a photosensitive substrate. By controlling the x-ray radiation dose from point-to-point, it is possible to control the development process for removing exposed portions of the substrate; adjusting it such that each of these portions develops at a more or less uniformly rate regardless of feature size or feature density distribution.

High aspect ratio sub-15 nm silicon trenches from block copolymer templates.

PubMed

Gu, Xiaodan; Liu, Zuwei; Gunkel, Ilja; Chourou, S T; Hong, Sung Woo; Olynick, Deirdre L; Russell, Thomas P

2012-11-08

High-aspect-ratio sub-15-nm silicon trenches are fabricated directly from plasma etching of a block copolymer mask. A novel method that combines a block copolymer reconstruction process and reactive ion etching is used to make the polymer mask. Silicon trenches are characterized by various methods and used as a master for subsequent imprinting of different materials. Silicon nanoholes are generated from a block copolymer with cylindrical microdomains oriented normal to the surface. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

You Can Hide but You Can't Run: Interdisciplinary and Culturally Sensitive Approaches to Mask Making

ERIC Educational Resources Information Center

Ballengee-Morris, Christine

2005-01-01

From papier mache to plaster and paper to moulage, making masks is a popular activity for both art educators and students around the world. Masks have been and are currently used by many cultures/societies for specific cultural rituals and spiritual, metaphorical, role-playing, and theatrical reasons. In short, their use and their creation are…

A tunable sub-100 nm silicon nanopore array with an AAO membrane mask: reducing unwanted surface etching by introducing a PMMA interlayer.

PubMed

Lim, Namsoo; Pak, Yusin; Kim, Jin Tae; Hwang, Youngkyu; Lee, Ryeri; Kumaresan, Yogeenth; Myoung, NoSoung; Ko, Heung Cho; Jung, Gun Young

2015-08-28

Highly ordered silicon (Si) nanopores with a tunable sub-100 nm diameter were fabricated by a CF4 plasma etching process using an anodic aluminum oxide (AAO) membrane as an etching mask. To enhance the conformal contact of the AAO membrane mask to the underlying Si substrate, poly(methyl methacrylate) (PMMA) was spin-coated on top of the Si substrate prior to the transfer of the AAO membrane. The AAO membrane mask was fabricated by two-step anodization and subsequent removal of the aluminum support and the barrier layer, which was then transferred to the PMMA-coated Si substrate. Contact printing was performed on the sample with a pressure of 50 psi and a temperature of 120 °C to make a conformal contact of the AAO membrane mask to the Si substrate. The CF4 plasma etching was conducted to transfer nanopores onto the Si substrate through the PMMA interlayer. The introduced PMMA interlayer prevented unwanted surface etching of the Si substrate by eliminating the etching ions and radicals bouncing at the gap between the mask and the substrate, resulting in a smooth Si nanopore array.

Tunable wavefront coded imaging system based on detachable phase mask: Mathematical analysis, optimization and underlying applications

NASA Astrophysics Data System (ADS)

Zhao, Hui; Wei, Jingxuan

2014-09-01

The key to the concept of tunable wavefront coding lies in detachable phase masks. Ojeda-Castaneda et al. (Progress in Electronics Research Symposium Proceedings, Cambridge, USA, July 5-8, 2010) described a typical design in which two components with cosinusoidal phase variation operate together to make defocus sensitivity tunable. The present study proposes an improved design and makes three contributions: (1) A mathematical derivation based on the stationary phase method explains why the detachable phase mask of Ojeda-Castaneda et al. tunes the defocus sensitivity. (2) The mathematical derivations show that the effective bandwidth wavefront coded imaging system is also tunable by making each component of the detachable phase mask move asymmetrically. An improved Fisher information-based optimization procedure was also designed to ascertain the optimal mask parameters corresponding to specific bandwidth. (3) Possible applications of the tunable bandwidth are demonstrated by simulated imaging.

Being forward not backward: lexical limits to masked priming.

PubMed

Davis, Chris; Kim, Jeesun; Forster, Kenneth I

2008-05-01

This study investigated whether masked priming is mediated by existing memory representations by determining whether nonwords targets would show repetition priming. To avoid the potential confound that nonword repetition priming would be obscured by a familiarity response bias, the standard lexical decision and naming tasks were modified to make targets unfamiliar. Participants were required to read a target string from right to left (i.e., "ECAF" should be read as "FACE") and then make a response. To examine if priming was based on lexical representations, repetition primes consisted of words when read forwards or backwards (e.g., "face", "ecaf") and nonwords (e.g., "pame", "emap"). Forward and backward primes were used to test if task instruction affected prime encoding. The lexical decision and naming tasks showed the same pattern of results: priming only occurred for forward primes with word targets (e.g., "face-ECAF"). Additional experiments to test if response priming affected the LDT indicated that the lexical status of the prime per se did not affect target responses. These results showed that the encoding of masked primes was unaffected by the novel task instruction and support the view that masked priming is due to the automatic triggering of pre-established computational processes based on stored information.

Improved Method of Manufacturing SiC Devices

NASA Technical Reports Server (NTRS)

Okojie, Robert S.

2005-01-01

The phrase, "common-layered architecture for semiconductor silicon carbide" ("CLASSiC") denotes a method of batch fabrication of microelectromechanical and semiconductor devices from bulk silicon carbide. CLASSiC is the latest in a series of related methods developed in recent years in continuing efforts to standardize SiC-fabrication processes. CLASSiC encompasses both institutional and technological innovations that can be exploited separately or in combination to make the manufacture of SiC devices more economical. Examples of such devices are piezoresistive pressure sensors, strain gauges, vibration sensors, and turbulence-intensity sensors for use in harsh environments (e.g., high-temperature, high-pressure, corrosive atmospheres). The institutional innovation is to manufacture devices for different customers (individuals, companies, and/or other entities) simultaneously in the same batch. This innovation is based on utilization of the capability for fabrication, on the same substrate, of multiple SiC devices having different functionalities (see figure). Multiple customers can purchase shares of the area on the same substrate, each customer s share being apportioned according to the customer s production-volume requirement. This makes it possible for multiple customers to share costs in a common foundry, so that the capital equipment cost per customer in the inherently low-volume SiC-product market can be reduced significantly. One of the technological innovations is a five-mask process that is based on an established set of process design rules. The rules provide for standardization of the fabrication process, yet are flexible enough to enable multiple customers to lay out masks for their portions of the SiC substrate to provide for simultaneous batch fabrication of their various devices. In a related prior method, denoted multi-user fabrication in silicon carbide (MUSiC), the fabrication process is based largely on surface micromachining of poly SiC. However, in MUSiC one cannot exploit the superior sensing, thermomechanical, and electrical properties of single-crystal 6H-SiC or 4H-SiC. As a complement to MUSiC, the CLASSiC five-mask process can be utilized to fabricate multiple devices in bulk single-crystal SiC of any polytype. The five-mask process makes fabrication less complex because it eliminates the need for large-area deposition and removal of sacrificial material. Other innovations in CLASSiC pertain to selective etching of indium tin oxide and aluminum in connection with multilayer metallization. One major characteristic of bulk micromachined microelectromechanical devices is the presence of three-dimensional (3D) structures. Any 3D recesses that already exist at a given step in a fabrication process usually make it difficult to apply a planar coat of photoresist for metallization and other subsequent process steps. To overcome this difficulty, the CLASSiC process includes a reversal of part of the conventional flow: Metallization is performed before the recesses are etched.

Study of data I/O performance on distributed disk system in mask data preparation

NASA Astrophysics Data System (ADS)

Ohara, Shuichiro; Odaira, Hiroyuki; Chikanaga, Tomoyuki; Hamaji, Masakazu; Yoshioka, Yasuharu

2010-09-01

Data volume is getting larger every day in Mask Data Preparation (MDP). In the meantime, faster data handling is always required. MDP flow typically introduces Distributed Processing (DP) system to realize the demand because using hundreds of CPU is a reasonable solution. However, even if the number of CPU were increased, the throughput might be saturated because hard disk I/O and network speeds could be bottlenecks. So, MDP needs to invest a lot of money to not only hundreds of CPU but also storage and a network device which make the throughput faster. NCS would like to introduce new distributed processing system which is called "NDE". NDE could be a distributed disk system which makes the throughput faster without investing a lot of money because it is designed to use multiple conventional hard drives appropriately over network. NCS studies I/O performance with OASIS® data format on NDE which contributes to realize the high throughput in this paper.

To repair or not to repair: with FAVOR there is no question

NASA Astrophysics Data System (ADS)

Garetto, Anthony; Schulz, Kristian; Tabbone, Gilles; Himmelhaus, Michael; Scheruebl, Thomas

2016-10-01

In the mask shop the challenges associated with today's advanced technology nodes, both technical and economic, are becoming increasingly difficult. The constant drive to continue shrinking features means more masks per device, smaller manufacturing tolerances and more complexity along the manufacturing line with respect to the number of manufacturing steps required. Furthermore, the extremely competitive nature of the industry makes it critical for mask shops to optimize asset utilization and processes in order to maximize their competitive advantage and, in the end, profitability. Full maximization of profitability in such a complex and technologically sophisticated environment simply cannot be achieved without the use of smart automation. Smart automation allows productivity to be maximized through better asset utilization and process optimization. Reliability is improved through the minimization of manual interactions leading to fewer human error contributions and a more efficient manufacturing line. In addition to these improvements in productivity and reliability, extra value can be added through the collection and cross-verification of data from multiple sources which provides more information about our products and processes. When it comes to handling mask defects, for instance, the process consists largely of time consuming manual interactions that are error prone and often require quick decisions from operators and engineers who are under pressure. The handling of defects itself is a multiple step process consisting of several iterations of inspection, disposition, repair, review and cleaning steps. Smaller manufacturing tolerances and features with higher complexity contribute to a higher number of defects which must be handled as well as a higher level of complexity. In this paper the recent efforts undertaken by ZEISS to provide solutions which address these challenges, particularly those associated with defectivity, will be presented. From automation of aerial image analysis to the use of data driven decision making to predict and propose the optimized back end of line process flow, productivity and reliability improvements are targeted by smart automation. Additionally the generation of the ideal aerial image from the design and several repair enhancement features offer additional capabilities to improve the efficiency and yield associated with defect handling.

Development for 2D pattern quantification method on mask and wafer

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Toyoda, Yasutaka; Wang, Zhigang

2010-03-01

We have developed the effective method of mask and silicon 2-dimensional metrology. The aim of this method is evaluating the performance of the silicon corresponding to Hotspot on a mask. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. 2-dimensional Shape quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. On the other hand, there is roughness in the silicon shape made from a mass-production line. Moreover, there is variation in the silicon shape. For this reason, quantification of silicon shape is important, in order to estimate the performance of a pattern. In order to quantify, the same shape is equalized in two dimensions. And the method of evaluating based on the shape is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. It is possible to analyze variability of the edge of the same position with high precision. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. - Estimate of the correlativity of shape variability and a process margin. - Determination of two-dimensional variability of pattern. - Verification of the performance of the pattern of various kinds of Hotspots. In this report, we introduce the experimental results and the application. We expect that the mask measurement and the shape control on mask production will make a huge contribution to mask yield-enhancement and that the DFM solution for mask quality control process will become much more important technology than ever. It is very important to observe the shape of the same location of Design, Mask, and Silicon in such a viewpoint.

[A method of synthesizing cicada sound for treatment of tinnitus].

PubMed

Wang, Yangjing; He, Peiyu; Pan, Fan; Cui, Tao; Wang, Haiyan

2013-06-01

Masking therapy can make patients accustom to tinnitus. This therapy is safe and easy to implement, so that it has become a widely used treatment of curing tinnitus. According to surveys of tinnitus sounds, cicada sound is one of the most usual tinnituses. Meanwhile, we have not hitherto found published papers concerning how to synthesize cicada sound and to use it to ameliorate tinnitus. Inspired by the human acoustics theory, we proposed a method to synthesize medical masking sound and to realize the diversity by illustrating the process of synthesizing various cicada sounds. In addition, energy attenuation problem in spectrum shifting process has been successfully solved. Simulation results indicated that the proposed method achieved decent results and would have practical value for the future applications.

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

NASA Astrophysics Data System (ADS)

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

2015-10-01

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

Design Architecture of field-effect transistor with back gate electrode for biosensor application

NASA Astrophysics Data System (ADS)

Fathil, M. F. M.; Arshad, M. K. Md.; Hashim, U.; Ruslinda, A. R.; Gopinath, Subash C. B.; M. Nuzaihan M., N.; Ayub, R. M.; Adzhri, R.; Zaki, M.; Azman, A. H.

2016-07-01

This paper presents the preparation method of photolithography chrome mask design used in fabrication process of field-effect transistor with back gate biasing based biosensor. Initially, the chrome masks are designed by studying the process flow of the biosensor fabrication, followed by drawing of the actual chrome mask using the AutoCAD software. The overall width and length of the device is optimized at 16 mm and 16 mm, respectively. Fabrication processes of the biosensor required five chrome masks, which included source and drain formation mask, the back gate area formation mask, electrode formation mask, front gate area formation mask, and passivation area formation mask. The complete chrome masks design will be sent for chrome mask fabrication and for future use in biosensor fabrication.

Developing a New Quantitative Account of Backward Masking

ERIC Educational Resources Information Center

Francis, Gregory

2003-01-01

A new general explanation for u-shaped backward masking is analyzed and found to predict shifts in the interstimulus interval (ISI) that produces strongest masking. This predicted shift is then compared to six sets of masking data. The resulting comparisons force the general explanation to make certain assumptions to account for the data. In this…

Evaluation of setup uncertainties for single-fraction SRS by comparing two different mask-creation methods

NASA Astrophysics Data System (ADS)

Baek, Jong Geun; Jang, Hyun Soo; Oh, Young Kee; Lee, Hyun Jeong; Kim, Eng Chan

2015-07-01

The purpose of this study was to evaluate the setup uncertainties for single-fraction stereotactic radiosurgery (SF-SRS) based on clinical data with two different mask-creation methods using pretreatment con-beam computed tomography imaging guidance. Dedicated frameless fixation Brain- LAB masks for 23 patients were created as a routine mask (R-mask) making method, as explained in the BrainLAB's user manual. Alternative masks (A-masks), which were created by modifying the cover range of the R-masks for the patient's head, were used for 23 patients. The systematic errors including these for each mask and stereotactic target localizer were analyzed, and the errors were calculated as the means ± standard deviations (SD) from the left-right (LR), superior-inferior (SI), anterior-posterior (AP), and yaw setup corrections. In addition, the frequencies of the threedimensional (3D) vector length were analyzed. The values of the mean setup corrections for the R-mask in all directions were < 0.7 mm and < 0.1°, whereas the magnitudes of the SDs were relatively large compared to the mean values. In contrast, the means and SDs of the A-mask were smaller than those for the R-mask with the exception of the SD in the AP direction. The means and SDs in the yaw rotational direction for the R-mask and the A-mask system were comparable. 3D vector shifts of larger magnitude occurred more frequently for the R-mask than the A-mask. The setup uncertainties for each mask with the stereotactic localizing system had an asymmetric offset towards the positive AP direction. The A-mask-creation method, which is capable of covering the top of the patient's head, is superior to that for the R-mask, so the use of the A-mask is encouraged for SF-SRS to reduce the setup uncertainties. Moreover, careful mask-making is required to prevent possible setup uncertainties.

Scatterometry on pelliclized masks: an option for wafer fabs

NASA Astrophysics Data System (ADS)

Gallagher, Emily; Benson, Craig; Higuchi, Masaru; Okumoto, Yasuhiro; Kwon, Michael; Yedur, Sanjay; Li, Shifang; Lee, Sangbong; Tabet, Milad

2007-03-01

Optical scatterometry-based metrology is now widely used in wafer fabs for lithography, etch, and CMP applications. This acceptance of a new metrology method occurred despite the abundance of wellestablished CD-SEM and AFM methods. It was driven by the desire to make measurements faster and with a lower cost of ownership. Over the last year, scatterometry has also been introduced in advanced mask shops for mask measurements. Binary and phase shift masks have been successfully measured at all desired points during photomask production before the pellicle is mounted. There is a significant benefit to measuring masks with the pellicle in place. From the wafer fab's perspective, through-pellicle metrology would verify mask effects on the same features that are characterized on wafer. On-site mask verification would enable quality control and trouble-shooting without returning the mask to a mask house. Another potential application is monitoring changes to mask films once the mask has been delivered to the fab (haze, oxide growth, etc.). Similar opportunities apply to the mask metrologist receiving line returns from a wafer fab. The ability to make line-return measurements without risking defect introduction is clearly attractive. This paper will evaluate the feasibility of collecting scatterometry data on pelliclized masks. We explore the effects of several different pellicle types on scatterometry measurements made with broadband light in the range of 320-780 nm. The complexity introduced by the pellicles' optical behavior will be studied.

Active-duty military service members’ visual representations of PTSD and TBI in masks

PubMed Central

Walker, Melissa S.; Kaimal, Girija; Gonzaga, Adele M. L.; Myers-Coffman, Katherine A.; DeGraba, Thomas J.

2017-01-01

ABSTRACT Active-duty military service members have a significant risk of sustaining physical and psychological trauma resulting in traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD). Within an interdisciplinary treatment approach at the National Intrepid Center of Excellence, service members participated in mask making during art therapy sessions. This study presents an analysis of the mask-making experiences of service members (n = 370) with persistent symptoms from combat- and mission-related TBI, PTSD, and other concurrent mood issues. Data sources included mask images and therapist notes collected over a five-year period. The data were coded and analyzed using grounded theory methods. Findings indicated that mask making offered visual representations of the self related to individual personhood, relationships, community, and society. Imagery themes referenced the injury, relational supports/losses, identity transitions/questions, cultural metaphors, existential reflections, and conflicted sense of self. These visual insights provided an increased understanding of the experiences of service members, facilitating their recovery. PMID:28452610

Active-duty military service members' visual representations of PTSD and TBI in masks.

PubMed

Walker, Melissa S; Kaimal, Girija; Gonzaga, Adele M L; Myers-Coffman, Katherine A; DeGraba, Thomas J

2017-12-01

Active-duty military service members have a significant risk of sustaining physical and psychological trauma resulting in traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD). Within an interdisciplinary treatment approach at the National Intrepid Center of Excellence, service members participated in mask making during art therapy sessions. This study presents an analysis of the mask-making experiences of service members (n = 370) with persistent symptoms from combat- and mission-related TBI, PTSD, and other concurrent mood issues. Data sources included mask images and therapist notes collected over a five-year period. The data were coded and analyzed using grounded theory methods. Findings indicated that mask making offered visual representations of the self related to individual personhood, relationships, community, and society. Imagery themes referenced the injury, relational supports/losses, identity transitions/questions, cultural metaphors, existential reflections, and conflicted sense of self. These visual insights provided an increased understanding of the experiences of service members, facilitating their recovery.

Reticle writer for next-generation SEMI mask standard: mask handling and exposure

NASA Astrophysics Data System (ADS)

Ehrlich, Christian

1998-12-01

The world semiconductor industry is currently preparing itself for the next evolutionary step in the ongoing development of the integrated circuit, characterized by the 0.18 to 0.15 micrometer technology. The already complex engineering task for the mask tool makers is furthermore complicated by the introduction of the new SEMI reticle standard with a 230 mm by 230 mm large and 9 mm thick quartz glass blank that will have a weight of more than one kilogram. The production of these advanced masks is already identified as a key enabling technology which will stretch the capabilities of the manufacturing process, and its equipment, to the limit. The mask making e-beam system Leica ZBA320, capable of exposing a 230 mm reticle and featuring the variable shaped beam approach with a 20 kV accelerating voltage has been introduced recently. Now the first results of e-beam exposures with this new type of mask writer are presented. Enhancements form the previous generation system include improved deflection systems, stage metrology, pattern data handling, and an address grid down to 10 nanometers. This system's specified performance enables it to produce reticles designed to support semiconductor fabrication utilizing 180 nanometer design rules, and beyond, with high accuracy and productivity.

Simulation based mask defect repair verification and disposition

NASA Astrophysics Data System (ADS)

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

2009-10-01

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

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

DOEpatents

Schiek, Richard [Albuquerque, NM

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.

Optimization of wavefront coding imaging system using heuristic algorithms

NASA Astrophysics Data System (ADS)

González-Amador, E.; Padilla-Vivanco, A.; Toxqui-Quitl, C.; Zermeño-Loreto, O.

2017-08-01

Wavefront Coding (WFC) systems make use of an aspheric Phase-Mask (PM) and digital image processing to extend the Depth of Field (EDoF) of computational imaging systems. For years, several kinds of PM have been designed to produce a point spread function (PSF) near defocus-invariant. In this paper, the optimization of the phase deviation parameter is done by means of genetic algorithms (GAs). In this, the merit function minimizes the mean square error (MSE) between the diffraction limited Modulated Transfer Function (MTF) and the MTF of the system that is wavefront coded with different misfocus. WFC systems were simulated using the cubic, trefoil, and 4 Zernike polynomials phase-masks. Numerical results show defocus invariance aberration in all cases. Nevertheless, the best results are obtained by using the trefoil phase-mask, because the decoded image is almost free of artifacts.

Awareness of subtle emotional feelings: a comparison of long-term meditators and nonmeditators.

PubMed

Nielsen, Lisbeth; Kaszniak, Alfred W

2006-08-01

The authors explored whether meditation training to enhance emotional awareness improves discrimination of subtle emotional feelings hypothesized to guide decision-making. Long-term meditators and nonmeditators were compared on measures of self-reported valence and arousal, skin conductance response (SCR), and facial electromyography (EMG) to masked and nonmasked emotional pictures, and on measures of heartbeat detection and self-reported emotional awareness. Groups responded similarly to nonmasked pictures. In the masked condition, only controls showed discrimination in valence self-reports. However, meditators reported greater emotional clarity than controls, and meditators with higher clarity had reduced arousal and improved valence discrimination in the masked condition. These findings provide qualified support for the somatic marker hypothesis and suggest that meditation may influence how emotionally ambiguous information is processed, regulated, and represented in conscious awareness. (c) 2006 APA, all rights reserved

Enhancement of security using structured phase masked in optical image encryption on Fresnel transform domain

NASA Astrophysics Data System (ADS)

Yadav, Poonam Lata; Singh, Hukum

2018-05-01

To enhance the security in optical image encryption system and to protect it from the attackers, this paper proposes new digital spiral phase mask based on Fresnel Transform. In this cryptosystem the Spiral Phase Mask (SPM) used is a hybrid of Fresnel Zone Plate (FZP) and Radial Hilbert Mask (RHM) which makes the key strong and enhances the security. The different keys used for encryption and decryption purposed make the system much more secure. Proposed scheme uses various structured phase mask which increases the key space also it increases the number of parameters which makes it difficult for the attackers to exactly find the key to recover the original image. We have also used different keys for encryption and decryption purpose to make the system much more secure. The strength of the proposed cryptosystem has been analyzed by simulating on MATLAB 7.9.0(R2008a). Mean Square Errors (MSE) and Peak Signal to Noise Ratio (PSNR) are calculated for the proposed algorithm. The experimental results are provided to highlight the effectiveness and sustainability of proposed cryptosystem and to prove that the cryptosystem is secure for usage.

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

NASA Astrophysics Data System (ADS)

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

2010-05-01

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

Are Masking-Based Models of Risk Useful?

PubMed

Gisiner, Robert C

2016-01-01

As our understanding of directly observable effects from anthropogenic sound exposure has improved, concern about "unobservable" effects such as stress and masking have received greater attention. Equal energy models of masking such as power spectrum models have the appeal of simplicity, but do they offer biologically realistic assessments of the risk of masking? Data relevant to masking such as critical ratios, critical bandwidths, temporal resolution, and directional resolution along with what is known about general mammalian antimasking mechanisms all argue for a much more complicated view of masking when making decisions about the risk of masking inherent in a given anthropogenic sound exposure scenario.

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.

Optical DC overlay measurement in the 2nd level process of 65 nm alternating phase shift mask

NASA Astrophysics Data System (ADS)

Ma, Jian; Han, Ke; Lee, Kyung; Korobko, Yulia; Silva, Mary; Chavez, Joas; Irvine, Brian; Henrichs, Sven; Chakravorty, Kishore; Olshausen, Robert; Chandramouli, Mahesh; Mammen, Bobby; Padmanaban, Ramaswamy

2005-11-01

Alternating phase shift mask (APSM) techniques help bridge the significant gap between the lithography wavelength and the patterning of minimum features, specifically, the poly line of 35 nm gate length (1x) in Intel's 65 nm technology. One of key steps in making APSM mask is to pattern to within the design tolerances the 2nd level resist so that the zero-phase apertures will be protected by the resist and the pi-phase apertures will be wide open for quartz etch. The ability to align the 2nd level to the 1st level binary pattern, i.e. the 2nd level overlay capability is very important, so is the capability of measuring the overlay accurately. Poor overlay could cause so-called the encroachment after quartz etch, producing undesired quartz bumps in the pi-apertures or quartz pits in the zero-apertures. In this paper, a simple, low-cost optical setup for the 2nd level DC (develop check) overlay measurements in the high volume manufacturing (HVM) of APSM masks is presented. By removing systematic errors in overlay associated with TIS and MIS (tool-induced shift and Mask-process induced shift), it is shown that this setup is capable of supporting the measurement of DC overlay with a tolerance as small as +/- 25 nm. The outstanding issues, such as DC overlay error component analysis, DC - FC (final check) overlay correlation and the overlay linearity (periphery vs. indie), are discussed.

Automated aerial image based CD metrology initiated by pattern marking with photomask layout data

NASA Astrophysics Data System (ADS)

Davis, Grant; Choi, Sun Young; Jung, Eui Hee; Seyfarth, Arne; van Doornmalen, Hans; Poortinga, Eric

2007-05-01

The photomask is a critical element in the lithographic image transfer process from the drawn layout to the final structures on the wafer. The non-linearity of the imaging process and the related MEEF impose a tight control requirement on the photomask critical dimensions. Critical dimensions can be measured in aerial images with hardware emulation. This is a more recent complement to the standard scanning electron microscope measurement of wafers and photomasks. Aerial image measurement includes non-linear, 3-dimensional, and materials effects on imaging that cannot be observed directly by SEM measurement of the mask. Aerial image measurement excludes the processing effects of printing and etching on the wafer. This presents a unique contribution to the difficult process control and modeling tasks in mask making. In the past, aerial image measurements have been used mainly to characterize the printability of mask repair sites. Development of photomask CD characterization with the AIMS TM tool was motivated by the benefit of MEEF sensitivity and the shorter feedback loop compared to wafer exposures. This paper describes a new application that includes: an improved interface for the selection of meaningful locations using the photomask and design layout data with the Calibre TM Metrology Interface, an automated recipe generation process, an automated measurement process, and automated analysis and result reporting on a Carl Zeiss AIMS TM system.

Photomask repeater strategy for high-quality and low-cost reticle fabrication

NASA Astrophysics Data System (ADS)

Kyoh, Suigen; Inoue, Soichi; Ikenaga, Osamu; Higaki, Tomotaka; Shigemitsu, Fumiaki; Mori, Ichiro; Kokubo, Haruo; Hayashi, Naoya; Irie, Nobuyuki; Ishii, Yuki; Umatate, Toshikazu

2003-08-01

The severe mask specification makes mask cost increase drastically. Especially, the increase in the mask cost deals ASIC businesses a fatal blow due to its small chip volume per product. Pattern writing cost has always occupied the main part of the prime mask cost and the emphasis of this is still increasing. This paper reports on a Photomask Repeater strategy to be a solution for reducing mask cost in pattern writing, comparing with conventional EB system.

How much is enough? An analysis of CD measurement amount for mask characterization

NASA Astrophysics Data System (ADS)

Ullrich, Albrecht; Richter, Jan

2009-10-01

The demands on CD (critical dimension) metrology amount in terms of both reproducibility and measurement uncertainty steadily increase from node to node. Different mask characterization requirements have to be addressed like very small features, unevenly distributed features, contacts, semi-dense structures to name only a few. Usually this enhanced need is met by an increasing number of CD measurements, where the new CD requirements are added to the well established CD characterization recipe. This leads straight forwardly to prolonged cycle times and highly complex evaluation routines. At the same time mask processes are continuously improved to become more stable. The enhanced stability offers potential to actually reduce the number of measurements. Thus, in this work we will start to address the fundamental question of how many CD measurements are needed for mask characterization for a given confidence level. We used analysis of variances (ANOVA) to distinguish various contributors like mask making process, measurement tool stability and measurement methodology. These contributions have been investigated for classical photomask CD specifications e.g. mean to target, CD uniformity, target offset tolerance and x-y bias. We found depending on specification that the importance of the contributors interchanges. Interestingly, not only short and long-term metrology contributions are dominant. Also the number of measurements and their spatial distribution on the mask layout (sampling methodology) can be the most important part of the variance. The knowledge of contributions can be used to optimize the sampling plan. As a major finding, we conclude that there is potential to reduce a significant amount of measurements without loosing confidence at all. Here, full sampling in x and y as well as full sampling for different features can be shortened substantially almost up to 50%.

Wafer hot spot identification through advanced photomask characterization techniques

NASA Astrophysics Data System (ADS)

Choi, Yohan; Green, Michael; McMurran, Jeff; Ham, Young; Lin, Howard; Lan, Andy; Yang, Richer; Lung, Mike

2016-10-01

As device manufacturers progress through advanced technology nodes, limitations in standard 1-dimensional (1D) mask Critical Dimension (CD) metrics are becoming apparent. Historically, 1D metrics such as Mean to Target (MTT) and CD Uniformity (CDU) have been adequate for end users to evaluate and predict the mask impact on the wafer process. However, the wafer lithographer's process margin is shrinking at advanced nodes to a point that the classical mask CD metrics are no longer adequate to gauge the mask contribution to wafer process error. For example, wafer CDU error at advanced nodes is impacted by mask factors such as 3-dimensional (3D) effects and mask pattern fidelity on subresolution assist features (SRAFs) used in Optical Proximity Correction (OPC) models of ever-increasing complexity. These items are not quantifiable with the 1D metrology techniques of today. Likewise, the mask maker needs advanced characterization methods in order to optimize the mask process to meet the wafer lithographer's needs. These advanced characterization metrics are what is needed to harmonize mask and wafer processes for enhanced wafer hot spot analysis. In this paper, we study advanced mask pattern characterization techniques and their correlation with modeled wafer performance.

Transient charge-masking effect of applied voltage on electrospinning of pure chitosan nanofibers from aqueous solutions.

PubMed

Terada, Dohiko; Kobayashi, Hisatoshi; Zhang, Kun; Tiwari, Ashutosh; Yoshikawa, Chiaki; Hanagata, Nobutaka

2012-02-01

The processing of a polyelectrolyte (whose functionality is derived from its ionized functional groups) into a nanofiber may improve its functionality and yield multiple functionalities. However, the electrospinning of nanofibers from polyelectrolytes is imperfect because polyelectrolytes differ considerably from neutral polymers in their rheological properties. In our study, we attempt to solve this problem by applying a voltage of opposite polarity to charges on a polyelectrolyte. The application of this 'countervoltage' can temporarily mask or screen a specific rheological property of the polyelectrolyte, making it behave as a neutral polymer. This approach can significantly contribute to the development of new functional nanofiber materials.

Micromachined microwave signal control device and method for making same

DOEpatents

Forman, Michael A [San Francisco, CA

2008-09-02

A method for fabricating a signal controller, e.g., a filter or a switch, for a coplanar waveguide during the LIGA fabrication process of the waveguide. Both patterns for the waveguide and patterns for the signal controllers are created on a mask. Radiation travels through the mask and reaches a photoresist layer on a substrate. The irradiated portions are removed and channels are formed on the substrate. A metal is filled into the channels to form the conductors of the waveguide and the signal controllers. Micromachined quasi-lumped elements are used alone or together as filters. The switch includes a comb drive, a spring, a metal plunger, and anchors.

Method for making a micromachined microwave signal control device

DOEpatents

Forman, Michael A [Mountain House, CA

2011-02-15

A method for fabricating a signal controller, e.g., a filter or a switch, for a coplanar waveguide during the LIGA fabrication process of the waveguide. Both patterns for the waveguide and patterns for the signal controllers are created on a mask. Radiation travels through the mask and reaches a photoresist layer on a substrate. The irradiated portions are removed and channels are formed on the substrate. A metal is filled into the channels to form the conductors of the waveguide and the signal controllers. Micromachined quasi-lumped elements are used alone or together as filters. The switch includes a comb drive, a spring, a metal plunger, and anchors.

African Mask-Making Workshop: Professional Development Experiences of Diverse Participants

ERIC Educational Resources Information Center

Rule, Audrey C.; Montgomery, Sarah E.; Kirkland-Holmes, Gloria; Watson, Dwight C.; Ayesiga, Yvonne

2015-01-01

Diverse education professionals learned about African cultures in a workshop experience by making African masks using authentic symbolism. Analysis of reflections to evaluate the workshop for applicability to participants with and without African heritage showed that both groups expanded their cultural knowledge of traditional African ethnic…

Preserved subliminal processing and impaired conscious access in schizophrenia

PubMed Central

Del Cul, Antoine; Dehaene, Stanislas; Leboyer, Marion

2006-01-01

Background Studies of visual backward masking have frequently revealed an elevated masking threshold in schizophrenia. This finding has frequently been interpreted as indicating a low-level visual deficit. However, more recent models suggest that masking may also involve late and higher-level integrative processes, while leaving intact early “bottom-up” visual processing. Objectives We tested the hypothesis that the backward masking deficit in schizophrenia corresponds to a deficit in the late stages of conscious perception, whereas the subliminal processing of masked stimuli is fully preserved. Method 28 patients with schizophrenia and 28 normal controls performed two backward-masking experiments. We used Arabic digits as stimuli and varied quasi-continuously the interval with a subsequent mask, thus allowing us to progressively “unmask” the stimuli. We finely quantified their degree of visibility using both objective and subjective measures to evaluate the threshold duration for access to consciousness. We also studied the priming effect caused by the variably masked numbers on a comparison task performed on a subsequently presented and highly visible target number. Results The threshold delay between digit and mask necessary for the conscious perception of the masked stimulus was longer in patients compared to control subjects. This higher consciousness threshold in patients was confirmed by an objective and a subjective measure, and both measures were highly correlated for patients as well as for controls. However, subliminal priming of masked numbers was effective and identical in patients compared to controls. Conclusions Access to conscious report of masked stimuli is impaired in schizophrenia, while fast bottom-up processing of the same stimuli, as assessed by subliminal priming, is preserved. These findings suggest a high-level origin of the masking deficit in schizophrenia, although they leave open for further research its exact relation to previously identified bottom-up visual processing abnormalities. PMID:17146006

Athermalization of infrared dual field optical system based on wavefront coding

NASA Astrophysics Data System (ADS)

Jiang, Kai; Jiang, Bo; Liu, Kai; Yan, Peipei; Duan, Jing; Shan, Qiu-sha

2017-02-01

Wavefront coding is a technology which combination of the optical design and digital image processing. By inserting a phase mask closed to the pupil plane of the optical system the wavefront of the system is re-modulated. And the depth of focus is extended consequently. In reality the idea is same as the athermalization theory of infrared optical system. In this paper, an uncooled infrared dual field optical system with effective focal as 38mm/19mm, F number as 1.2 of both focal length, operating wavelength varying from 8μm to 12μm was designed. A cubic phase mask was used at the pupil plane to re-modulate the wavefront. Then the performance of the infrared system was simulated with CODEV as the environment temperature varying from -40° to 60°. MTF curve of the optical system with phase mask are compared with the outcome before using phase mask. The result show that wavefront coding technology can make the system not sensitive to thermal defocus, and then realize the athermal design of the infrared optical system.

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.

Expanding the printable design space for lithography processes utilizing a cut mask

NASA Astrophysics Data System (ADS)

Wandell, Jerome; Salama, Mohamed; Wilkinson, William; Curtice, Mark; Feng, Jui-Hsuan; Gao, Shao Wen; Asthana, Abhishek

2016-03-01

The utilization of a cut-mask in semiconductor patterning processes has been in practice for logic devices since the inception of 32nm-node devices, notably with unidirectional gate level printing. However, the microprocessor applications where cut-mask patterning methods are used are expanding as Self-Aligned Double Patterning (SADP) processes become mainstream for 22/14nm fin diffusion, and sub-14nm metal levels. One common weakness for these types of lithography processes is that the initial pattern requiring the follow-up cut-mask typically uses an extreme off-axis imaging source such as dipole to enhance the resolution and line-width roughness (LWR) for critical dense patterns. This source condition suffers from poor process margin in the semi-dense (forbidden pitch) realm and wrong-way directional design spaces. Common pattern failures in these limited design regions include bridging and extra-printing defects that are difficult to resolve with traditional mask improvement means. This forces the device maker to limit the allowable geometries that a designer may use on a device layer. This paper will demonstrate methods to expand the usable design space on dipole-like processes such as unidirectional gate and SADP processes by utilizing the follow-up cut mask to improve the process window. Traditional mask enhancement means for improving the process window in this design realm will be compared to this new cut-mask approach. The unique advantages and disadvantages of the cut-mask solution will be discussed in contrast to those customary methods.

AutoMOPS--B2B and B2C in mask making: mask manufacturing performance and customer satisfaction improvement through better information flow management

NASA Astrophysics Data System (ADS)

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

2001-04-01

Through application of modern supply chain concepts in combination with state-of-the-art information technology, mask manufacturing performance and customer satisfaction can be improved radically. The AutoMOPS solution emphasizes on the elimination of the order verification through paperless, electronically linked information sharing/exchange between chip design, mask production and prototype production stages.

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

NASA Astrophysics Data System (ADS)

Hector, Scott

2005-11-01

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

Selective spatial attention modulates bottom-up informational masking of speech

PubMed Central

Carlile, Simon; Corkhill, Caitlin

2015-01-01

To hear out a conversation against other talkers listeners overcome energetic and informational masking. Largely attributed to top-down processes, information masking has also been demonstrated using unintelligible speech and amplitude-modulated maskers suggesting bottom-up processes. We examined the role of speech-like amplitude modulations in information masking using a spatial masking release paradigm. Separating a target talker from two masker talkers produced a 20 dB improvement in speech reception threshold; 40% of which was attributed to a release from informational masking. When across frequency temporal modulations in the masker talkers are decorrelated the speech is unintelligible, although the within frequency modulation characteristics remains identical. Used as a masker as above, the information masking accounted for 37% of the spatial unmasking seen with this masker. This unintelligible and highly differentiable masker is unlikely to involve top-down processes. These data provides strong evidence of bottom-up masking involving speech-like, within-frequency modulations and that this, presumably low level process, can be modulated by selective spatial attention. PMID:25727100

Selective spatial attention modulates bottom-up informational masking of speech.

PubMed

Carlile, Simon; Corkhill, Caitlin

2015-03-02

To hear out a conversation against other talkers listeners overcome energetic and informational masking. Largely attributed to top-down processes, information masking has also been demonstrated using unintelligible speech and amplitude-modulated maskers suggesting bottom-up processes. We examined the role of speech-like amplitude modulations in information masking using a spatial masking release paradigm. Separating a target talker from two masker talkers produced a 20 dB improvement in speech reception threshold; 40% of which was attributed to a release from informational masking. When across frequency temporal modulations in the masker talkers are decorrelated the speech is unintelligible, although the within frequency modulation characteristics remains identical. Used as a masker as above, the information masking accounted for 37% of the spatial unmasking seen with this masker. This unintelligible and highly differentiable masker is unlikely to involve top-down processes. These data provides strong evidence of bottom-up masking involving speech-like, within-frequency modulations and that this, presumably low level process, can be modulated by selective spatial attention.

Study of shape evaluation for mask and silicon using large field of view

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

2010-09-01

We have developed a highly integrated method of mask and silicon metrology. The aim of this integration is evaluating the performance of the silicon corresponding to Hotspot on a mask. It can use the mask shape of a large field, besides. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. As an optimal solution to these issues, we provide a DFM solution that extracts 2-dimensional data for a more realistic and error-free simulation by reproducing accurately the contour of the actual mask, in addition to the simulation results from the mask data. On the other hand, there is roughness in the silicon form made from a mass-production line. Moreover, there is variation in the silicon form. For this reason, quantification of silicon form is important, in order to estimate the performance of a pattern. In order to quantify, the same form is equalized in two dimensions. And the method of evaluating based on the form is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. •Discrimination of nuisance defects for fine pattern. •Determination of two-dimensional variability of pattern. •Verification of the performance of the pattern of various kinds of Hotspots. In this report, we introduce the experimental results and the application. We expect that the mask measurement and the shape control on mask production will make a huge contribution to mask yield-enhancement and that the DFM solution for mask quality control process will become much more important technology than ever. It is very important to observe the form of the same location of Design, Mask, and Silicon in such a viewpoint. And we report it about algorithm of the image composition in Large Field.

Facile preparation of porous alumina through-hole masks for sputtering by two-layer anodization

NASA Astrophysics Data System (ADS)

Yanagishita, Takashi; Masuda, Hideki

2016-08-01

Highly ordered porous alumina through-hole masks were fabricated on a substrate by combining two-layer anodization with subsequent through-holing by selective etching. This process allowed the fabrication of porous alumina masks without an increase in pore size during the etching performed for through-holing. Additionally, the process contributed to improved operability in the setting of the masks on substrates because the second anodizing layer acts as a supporting layer for the handling of the mask. The fabrication of ordered Au nanodot arrays was demonstrated as an example application of the through-hole masks obtained by the present process.

Direct Mask Overlay Inspection

NASA Astrophysics Data System (ADS)

Hsia, Liang-Choo; Su, Lo-Soun

1983-11-01

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

Grayscale lithography-automated mask generation for complex three-dimensional topography

NASA Astrophysics Data System (ADS)

Loomis, James; Ratnayake, Dilan; McKenna, Curtis; Walsh, Kevin M.

2016-01-01

Grayscale lithography is a relatively underutilized technique that enables fabrication of three-dimensional (3-D) microstructures in photosensitive polymers (photoresists). By spatially modulating ultraviolet (UV) dosage during the writing process, one can vary the depth at which photoresist is developed. This means complex structures and bioinspired designs can readily be produced that would otherwise be cost prohibitive or too time intensive to fabricate. The main barrier to widespread grayscale implementation, however, stems from the laborious generation of mask files required to create complex surface topography. We present a process and associated software utility for automatically generating grayscale mask files from 3-D models created within industry-standard computer-aided design (CAD) suites. By shifting the microelectromechanical systems (MEMS) design onus to commonly used CAD programs ideal for complex surfacing, engineering professionals already familiar with traditional 3-D CAD software can readily utilize their pre-existing skills to make valuable contributions to the MEMS community. Our conversion process is demonstrated by prototyping several samples on a laser pattern generator-capital equipment already in use in many foundries. Finally, an empirical calibration technique is shown that compensates for nonlinear relationships between UV exposure intensity and photoresist development depth as well as a thermal reflow technique to help smooth microstructure surfaces.

Mask Making in Human Services Education: A Case for Student Engagement

ERIC Educational Resources Information Center

Lashewicz, Bonnie; McGrath, Jenny; Smyth, Maria

2014-01-01

This article is an examination of strategies for engaging students in programs of human services education. We describe an in class mask-making activity, used by three human services instructors at an undergraduate university in western Canada, as a means of engaging students to grow in individual and collaborative awareness and skills. We present…

Preschoolers' Person Description and Identification Accuracy: A Comparison of the Simultaneous and Elimination Lineup Procedures

ERIC Educational Resources Information Center

Pozzulo, Joanna D.; Dempsey, Julie; Crescini, Charmagne

2009-01-01

Preschoolers' (3- to 6-year-olds) person description and identification abilities were examined using the simultaneous and elimination lineup procedures. Participants (N = 100) were exposed to a 20-minute mask-making session conducted by a female confederate who acted as the mask-making teacher. After a brief delay (20 min), participants were…

Recovery from Object Substitution Masking Induced by Transient Suppression of Visual Motion Processing: A Repetitive Transcranial Magnetic Stimulation Study

ERIC Educational Resources Information Center

Hirose, Nobuyuki; Kihara, Ken; Mima, Tatsuya; Ueki, Yoshino; Fukuyama, Hidenao; Osaka, Naoyuki

2007-01-01

Object substitution masking is a form of visual backward masking in which a briefly presented target is rendered invisible by a lingering mask that is too sparse to produce lower image-level interference. Recent studies suggested the importance of an updating process in a higher object-level representation, which should rely on the processing of…

Effect of SPM-based cleaning POR on EUV mask performance

NASA Astrophysics Data System (ADS)

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

2011-11-01

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

Challenges of anamorphic high-NA lithography and mask making

NASA Astrophysics Data System (ADS)

Hsu, Stephen D.; Liu, Jingjing

2017-06-01

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

Maskless lithography using off-the-shelf inkjet printer

NASA Astrophysics Data System (ADS)

Seng, Leo Cheng; Chollet, Franck

2006-12-01

Photolithography is the most important process used to pattern the surface of silicon wafers in IC fabrication. It has shown high performance but its use is not cost-effective for small series or prototyping as it necessitates a costly infrastructure (mask aligner) and requires the fabrication of masks which can be expensive and timeconsuming. Recently, the high resolution achieved by ink-jet printer (> 1200 DPI) starts to make an interesting alternative to obtain a patterned protective layer instead of using photolithography. This is particularly true for MEMS which often need a resolution of only 10 to 20 μm. After studying the different architecture of inkjet printer available in the market, a commercial S$100-printer was selected and modified to allow printing on a rigid silicon wafer. We then developed three different patterning processes using the printer. In a first process the ink was directly used as a protective layer for patterning. A second process modified the photolithography by using the printed ink as a photo-mask on a spun layer of photoresist. In each case we had to modify the surface energy of the wafer by surface treatment to improve the resolution. Finally we replaced the ink with a modified photoresist solution and directly printed a protective mask onto the wafer. Design of Experiment (DOE) methods were systematically employed to study the main and interaction effects of the parameters on the lithography and on the pattern transfer. The series of experiment showed that off-the-shelf ink-jet printer could be used easily for pattern with a resolution below 50 μm, but could not yet reach the 20 μm range.

An integrated theory of attention and decision making in visual signal detection.

PubMed

Smith, Philip L; Ratcliff, Roger

2009-04-01

The simplest attentional task, detecting a cued stimulus in an otherwise empty visual field, produces complex patterns of performance. Attentional cues interact with backward masks and with spatial uncertainty, and there is a dissociation in the effects of these variables on accuracy and on response time. A computational theory of performance in this task is described. The theory links visual encoding, masking, spatial attention, visual short-term memory (VSTM), and perceptual decision making in an integrated dynamic framework. The theory assumes that decisions are made by a diffusion process driven by a neurally plausible, shunting VSTM. The VSTM trace encodes the transient outputs of early visual filters in a durable form that is preserved for the time needed to make a decision. Attention increases the efficiency of VSTM encoding, either by increasing the rate of trace formation or by reducing the delay before trace formation begins. The theory provides a detailed, quantitative account of attentional effects in spatial cuing tasks at the level of response accuracy and the response time distributions. (c) 2009 APA, all rights reserved

EUV mask manufacturing readiness in the merchant mask industry

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Altered affective response in marijuana smokers: an FMRI study.

PubMed

Gruber, Staci A; Rogowska, Jadwiga; Yurgelun-Todd, Deborah A

2009-11-01

More than 94 million Americans have tried marijuana, and it remains the most widely used illicit drug in the nation. Investigations of the cognitive effects of marijuana report alterations in brain function during tasks requiring executive control, including inhibition and decision-making. Endogenous cannabinoids regulate a variety of emotional responses, including anxiety, mood control, and aggression; nevertheless, little is known about smokers' responses to affective stimuli. The anterior cingulate and amygdala play key roles in the inhibition of impulsive behavior and affective regulation, and studies using PET and fMRI have demonstrated changes within these regions in marijuana smokers. Given alterations in mood and perception often observed in smokers, we hypothesized altered fMRI patterns of response in 15 chronic heavy marijuana smokers relative to 15 non-marijuana smoking control subjects during the viewing of masked happy and fearful faces. Despite no between-group differences on clinical or demographic measures, smokers demonstrated a relative decrease in both anterior cingulate and amygdalar activity during masked affective stimuli compared to controls, who showed relative increases in activation within these regions during the viewing of masked faces. Findings indicate that chronic heavy marijuana smokers demonstrate altered activation of frontal and limbic systems while viewing masked faces, consistent with autoradiographic studies reporting high CB-1 receptor density in these regions. These data suggest differences in affective processing in chronic smokers, even when stimuli are presented below the level of conscious processing, and underscore the likelihood that marijuana smokers process emotional information differently from those who do not smoke, which may result in negative consequences.

EUVL masks: paving the path for commercialization

NASA Astrophysics Data System (ADS)

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

2001-09-01

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

Auditory processing efficiency deficits in children with developmental language impairments

NASA Astrophysics Data System (ADS)

Hartley, Douglas E. H.; Moore, David R.

2002-12-01

The ``temporal processing hypothesis'' suggests that individuals with specific language impairments (SLIs) and dyslexia have severe deficits in processing rapidly presented or brief sensory information, both within the auditory and visual domains. This hypothesis has been supported through evidence that language-impaired individuals have excess auditory backward masking. This paper presents an analysis of masking results from several studies in terms of a model of temporal resolution. Results from this modeling suggest that the masking results can be better explained by an ``auditory efficiency'' hypothesis. If impaired or immature listeners have a normal temporal window, but require a higher signal-to-noise level (poor processing efficiency), this hypothesis predicts the observed small deficits in the simultaneous masking task, and the much larger deficits in backward and forward masking tasks amongst those listeners. The difference in performance on these masking tasks is predictable from the compressive nonlinearity of the basilar membrane. The model also correctly predicts that backward masking (i) is more prone to training effects, (ii) has greater inter- and intrasubject variability, and (iii) increases less with masker level than do other masking tasks. These findings provide a new perspective on the mechanisms underlying communication disorders and auditory masking.

Mechanical microencapsulation: The best technique in taste masking for the manufacturing scale - Effect of polymer encapsulation on drug targeting.

PubMed

Al-Kasmi, Basheer; Alsirawan, Mhd Bashir; Bashimam, Mais; El-Zein, Hind

2017-08-28

Drug taste masking is a crucial process for the preparation of pediatric and geriatric formulations as well as fast dissolving tablets. Taste masking techniques aim to prevent drug release in saliva and at the same time to obtain the desired release profile in gastrointestinal tract. Several taste masking methods are reported, however this review has focused on a group of promising methods; complexation, encapsulation, and hot melting. The effects of each method on the physicochemical properties of the drug are described in details. Furthermore, a scoring system was established to evaluate each process using recent published data of selected factors. These include, input, process, and output factors that are related to each taste masking method. Input factors include the attributes of the materials used for taste masking. Process factors include equipment type and process parameters. Finally, output factors, include taste masking quality and yield. As a result, Mechanical microencapsulation obtained the highest score (5/8) along with complexation with cyclodextrin suggesting that these methods are the most preferable for drug taste masking. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative evaluation of manufacturability and performance for ILT produced mask shapes using a single-objective function

NASA Astrophysics Data System (ADS)

Choi, Heon; Wang, Wei-long; Kallingal, Chidam

2015-03-01

The continuous scaling of semiconductor devices is quickly outpacing the resolution improvements of lithographic exposure tools and processes. This one-sided progression has pushed optical lithography to its limits, resulting in the use of well-known techniques such as Sub-Resolution Assist Features (SRAF's), Source-Mask Optimization (SMO), and double-patterning, to name a few. These techniques, belonging to a larger category of Resolution Enhancement Techniques (RET), have extended the resolution capabilities of optical lithography at the cost of increasing mask complexity, and therefore cost. One such technique, called Inverse Lithography Technique (ILT), has attracted much attention for its ability to produce the best possible theoretical mask design. ILT treats the mask design process as an inverse problem, where the known transformation from mask to wafer is carried out backwards using a rigorous mathematical approach. One practical problem in the application of ILT is the resulting contour-like mask shapes that must be "Manhattanized" (composed of straight edges and 90-deg corners) in order to produce a manufacturable mask. This conversion process inherently degrades the mask quality as it is a departure from the "optimal mask" represented by the continuously curved shapes produced by ILT. However, simpler masks composed of longer straight edges reduce the mask cost as it lowers the shot count and saves mask writing time during mask fabrication, resulting in a conflict between manufacturability and performance for ILT produced masks1,2. In this study, various commonly used metrics will be combined into an objective function to produce a single number to quantitatively measure a particular ILT solution's ability to balance mask manufacturability and RET performance. Several metrics that relate to mask manufacturing costs (i.e. mask vertex count, ILT computation runtime) are appropriately weighted against metrics that represent RET capability (i.e. process-variation band, edge-placement-error) in order to reflect the desired practical balance. This well-defined scoring system allows direct comparison of several masks with varying degrees of complexities. Using this method, ILT masks produced with increasing mask constraints will be compared, and it will be demonstrated that using the smallest minimum width for mask shapes does not always produce the optimal solution.

Masking disrupts reentrant processing in human visual cortex.

PubMed

Fahrenfort, J J; Scholte, H S; Lamme, V A F

2007-09-01

In masking, a stimulus is rendered invisible through the presentation of a second stimulus shortly after the first. Over the years, authors have typically explained masking by postulating some early disruption process. In these feedforward-type explanations, the mask somehow "catches up" with the target stimulus, disrupting its processing either through lateral or interchannel inhibition. However, studies from recent years indicate that visual perception--and most notably visual awareness itself--may depend strongly on cortico-cortical feedback connections from higher to lower visual areas. This has led some researchers to propose that masking derives its effectiveness from selectively interrupting these reentrant processes. In this experiment, we used electroencephalogram measurements to determine what happens in the human visual cortex during detection of a texture-defined square under nonmasked (seen) and masked (unseen) conditions. Electro-encephalogram derivatives that are typically associated with reentrant processing turn out to be absent in the masked condition. Moreover, extrastriate visual areas are still activated early on by both seen and unseen stimuli, as shown by scalp surface Laplacian current source-density maps. This conclusively shows that feedforward processing is preserved, even when subject performance is at chance as determined by objective measures. From these results, we conclude that masking derives its effectiveness, at least partly, from disrupting reentrant processing, thereby interfering with the neural mechanisms of figure-ground segmentation and visual awareness itself.

Comparison of DNQ/novolac resists for e-beam exposure

NASA Astrophysics Data System (ADS)

Fedynyshyn, Theodore H.; Doran, Scott P.; Lind, Michele L.; Lyszczarz, Theodore M.; DiNatale, William F.; Lennon, Donna; Sauer, Charles A.; Meute, Jeff

1999-12-01

We have surveyed the commercial resist market with the dual purpose of identifying diazoquinone/novolac based resists that have potential for use as e-beam mask making resists and baselining these resists for comparison against future mask making resist candidates. For completeness, this survey would require that each resist be compared with an optimized developer and development process. To accomplish this task in an acceptable time period, e-beam lithography modeling was employed to quickly identify the resist and developer combinations that lead to superior resist performance. We describe the verification of a method to quickly screen commercial i-line resists with different developers, by determining modeling parameters for i-line resists from e-beam exposures, modeling the resist performance, and comparing predicted performance versus actual performance. We determined the lithographic performance of several DNQ/novolac resists whose modeled performance suggests that sensitivities of less than 40 (mu) C/cm2 coupled with less than 10-nm CD change per percent change in dose are possible for target 600-nm features. This was accomplished by performing a series of statistically designed experiments on the leading resists candidates to optimize processing variables, followed by comparing experimentally determined resist sensitivities, latitudes, and profiles of the DNQ/novolac resists a their optimized process.

Invited Article: Mask-modulated lensless imaging with multi-angle illuminations

NASA Astrophysics Data System (ADS)

Zhang, Zibang; Zhou, You; Jiang, Shaowei; Guo, Kaikai; Hoshino, Kazunori; Zhong, Jingang; Suo, Jinli; Dai, Qionghai; Zheng, Guoan

2018-06-01

The use of multiple diverse measurements can make lensless phase retrieval more robust. Conventional diversity functions include aperture diversity, wavelength diversity, translational diversity, and defocus diversity. Here we discuss a lensless imaging scheme that employs multiple spherical-wave illuminations from a light-emitting diode array as diversity functions. In this scheme, we place a binary mask between the sample and the detector for imposing support constraints for the phase retrieval process. This support constraint enforces the light field to be zero at certain locations and is similar to the aperture constraint in Fourier ptychographic microscopy. We use a self-calibration algorithm to correct the misalignment of the binary mask. The efficacy of the proposed scheme is first demonstrated by simulations where we evaluate the reconstruction quality using mean square error and structural similarity index. The scheme is then experimentally tested by recovering images of a resolution target and biological samples. The proposed scheme may provide new insights for developing compact and large field-of-view lensless imaging platforms. The use of the binary mask can also be combined with other diversity functions for better constraining the phase retrieval solution space. We provide the open-source implementation code for the broad research community.

Optical image encryption via high-quality computational ghost imaging using iterative phase retrieval

NASA Astrophysics Data System (ADS)

Liansheng, Sui; Yin, Cheng; Bing, Li; Ailing, Tian; Krishna Asundi, Anand

2018-07-01

A novel computational ghost imaging scheme based on specially designed phase-only masks, which can be efficiently applied to encrypt an original image into a series of measured intensities, is proposed in this paper. First, a Hadamard matrix with a certain order is generated, where the number of elements in each row is equal to the size of the original image to be encrypted. Each row of the matrix is rearranged into the corresponding 2D pattern. Then, each pattern is encoded into the phase-only masks by making use of an iterative phase retrieval algorithm. These specially designed masks can be wholly or partially used in the process of computational ghost imaging to reconstruct the original information with high quality. When a significantly small number of phase-only masks are used to record the measured intensities in a single-pixel bucket detector, the information can be authenticated without clear visualization by calculating the nonlinear correlation map between the original image and its reconstruction. The results illustrate the feasibility and effectiveness of the proposed computational ghost imaging mechanism, which will provide an effective alternative for enriching the related research on the computational ghost imaging technique.

Metacontrast masking is processed before grapheme-color synesthesia.

PubMed

Bacon, Michael Patrick; Bridgeman, Bruce; Ramachandran, Vilayanur S

2013-01-01

We investigated the physiological mechanism of grapheme-color synesthesia using metacontrast masking. A metacontrast target is rendered invisible by a mask that is delayed by about 60 ms; the target and mask do not overlap in space or time. Little masking occurs, however, if the target and mask are simultaneous. This effect must be cortical, because it can be obtained dichoptically. To compare the data for synesthetes and controls, we developed a metacontrast design in which nonsynesthete controls showed weaker dichromatic masking (i.e., the target and mask were in different colors) than monochromatic masking. We accomplished this with an equiluminant target, mask, and background for each observer. If synesthetic color affected metacontrast, synesthetes should show monochromatic masking more similar to the weak dichromatic masking among controls, because synesthetes could add their synesthetic color to the monochromatic condition. The target-mask pairs used for each synesthete were graphemes that elicited strong synesthetic colors. We found stronger monochromatic than dichromatic U-shaped metacontrast for both synesthetes and controls, with optimal masking at an asynchrony of 66 ms. The difference in performance between the monochromatic and dichromatic conditions in the synesthetes indicates that synesthesia occurs at a later processing stage than does metacontrast masking.

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.

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.

Perceptual Discrimination of Basic Object Features Is Not Facilitated When Priming Stimuli Are Prevented From Reaching Awareness by Means of Visual Masking

PubMed Central

Peel, Hayden J.; Sperandio, Irene; Laycock, Robin; Chouinard, Philippe A.

2018-01-01

Our understanding of how form, orientation and size are processed within and outside of awareness is limited and requires further investigation. Therefore, we investigated whether or not the visual discrimination of basic object features can be influenced by subliminal processing of stimuli presented beforehand. Visual masking was used to render stimuli perceptually invisible. Three experiments examined if visible and invisible primes could facilitate the subsequent feature discrimination of visible targets. The experiments differed in the kind of perceptual discrimination that participants had to make. Namely, participants were asked to discriminate visual stimuli on the basis of their form, orientation, or size. In all three experiments, we demonstrated reliable priming effects when the primes were visible but not when the primes were made invisible. Our findings underscore the importance of conscious awareness in facilitating the perceptual discrimination of basic object features. PMID:29725292

A simple method of fabricating mask-free microfluidic devices for biological analysis

PubMed Central

Yi, Xin; Kodzius, Rimantas; Gong, Xiuqing; Xiao, Kang; Wen, Weijia

2010-01-01

We report a simple, low-cost, rapid, and mask-free method to fabricate two-dimensional (2D) and three-dimensional (3D) microfluidic chip for biological analysis researches. In this fabrication process, a laser system is used to cut through paper to form intricate patterns and differently configured channels for specific purposes. Bonded with cyanoacrylate-based resin, the prepared paper sheet is sandwiched between glass slides (hydrophilic) or polymer-based plates (hydrophobic) to obtain a multilayer structure. In order to examine the chip’s biocompatibility and applicability, protein concentration was measured while DNA capillary electrophoresis was carried out, and both of them show positive results. With the utilization of direct laser cutting and one-step gas-sacrificing techniques, the whole fabrication processes for complicated 2D and 3D microfluidic devices are shorten into several minutes which make it a good alternative of poly(dimethylsiloxane) microfluidic chips used in biological analysis researches. PMID:20890452

Perceptual Discrimination of Basic Object Features Is Not Facilitated When Priming Stimuli Are Prevented From Reaching Awareness by Means of Visual Masking.

PubMed

Peel, Hayden J; Sperandio, Irene; Laycock, Robin; Chouinard, Philippe A

2018-01-01

Our understanding of how form, orientation and size are processed within and outside of awareness is limited and requires further investigation. Therefore, we investigated whether or not the visual discrimination of basic object features can be influenced by subliminal processing of stimuli presented beforehand. Visual masking was used to render stimuli perceptually invisible. Three experiments examined if visible and invisible primes could facilitate the subsequent feature discrimination of visible targets. The experiments differed in the kind of perceptual discrimination that participants had to make. Namely, participants were asked to discriminate visual stimuli on the basis of their form, orientation, or size. In all three experiments, we demonstrated reliable priming effects when the primes were visible but not when the primes were made invisible. Our findings underscore the importance of conscious awareness in facilitating the perceptual discrimination of basic object features.

A method for evaluating the relation between sound source segregation and masking

PubMed Central

Lutfi, Robert A.; Liu, Ching-Ju

2011-01-01

Sound source segregation refers to the ability to hear as separate entities two or more sound sources comprising a mixture. Masking refers to the ability of one sound to make another sound difficult to hear. Often in studies, masking is assumed to result from a failure of segregation, but this assumption may not always be correct. Here a method is offered to identify the relation between masking and sound source segregation in studies and an example is given of its application. PMID:21302979

Subliminal Gestalt grouping: evidence of perceptual grouping by proximity and similarity in absence of conscious perception.

PubMed

Montoro, Pedro R; Luna, Dolores; Ortells, Juan J

2014-04-01

Previous studies making use of indirect processing measures have shown that perceptual grouping can occur outside the focus of attention. However, no previous study has examined the possibility of subliminal processing of perceptual grouping. The present work steps forward in the study of perceptual organization, reporting direct evidence of subliminal processing of Gestalt patterns. In two masked priming experiments, Gestalt patterns grouped by proximity or similarity that induced either a horizontal or vertical global orientation of the stimuli were presented as masked primes and followed by visible targets that could be congruent or incongruent with the orientation of the primes. The results showed a reliable priming effect in the complete absence of prime awareness for both proximity and similarity grouping principles. These findings suggest that a phenomenal report of the Gestalt pattern is not mandatory to observe an effect on the response based on the global properties of Gestalt stimuli. Copyright © 2014 Elsevier Inc. All rights reserved.

Cost-effective masks for deep x-ray lithography

NASA Astrophysics Data System (ADS)

Scheunemann, Heinz-Ulrich; Loechel, Bernd; Jian, Linke; Schondelmaier, Daniel; Desta, Yohannes M.; Goettert, Jost

2003-04-01

The production of X-ray masks is one of the key techniques for X-ray lithography and the LIGA process. Different ways for the fabrication of X-ray masks has been established. Very sophisticated, difficult and expensive procedures are required to produce high precision and high quality X-ray masks. In order to minimize the cost of an X-ray mask, the mask blank must be inexpensive and readily available. The steps involved in the fabrication process must also be minimal. In the past, thin membranes made of titanium, silicon carbide, silicon nitride (2-5μm) or thick beryllium substrates (500μm) have been used as mask blanks. Thin titanium and silicon compounds have very high transparency for X-rays; therefore, these materials are predestined for use as mask membrane material. However, the handling and fabrication of thin membranes is very difficult, thus expensive. Beryllium is highly transparent to X-rays, but the processing and use of beryllium is risky due to potential toxicity. During the past few years graphite based X-ray masks have been in use at various research centers, but the sidewall quality of the generated resist patterns is in the range of 200-300 nm Ra. We used polished graphite to improve the sidewall roughness, but polished graphite causes other problems in the fabrication of X-ray masks. This paper describes the advantages associated with the use of polished graphite as mask blank as well as the fabrication process for this low cost X-ray mask. Alternative membrane materials will also be discussed.

Detection of pigment network in dermoscopy images using supervised machine learning and structural analysis.

PubMed

García Arroyo, Jose Luis; García Zapirain, Begoña

2014-01-01

By means of this study, a detection algorithm for the "pigment network" in dermoscopic images is presented, one of the most relevant indicators in the diagnosis of melanoma. The design of the algorithm consists of two blocks. In the first one, a machine learning process is carried out, allowing the generation of a set of rules which, when applied over the image, permit the construction of a mask with the pixels candidates to be part of the pigment network. In the second block, an analysis of the structures over this mask is carried out, searching for those corresponding to the pigment network and making the diagnosis, whether it has pigment network or not, and also generating the mask corresponding to this pattern, if any. The method was tested against a database of 220 images, obtaining 86% sensitivity and 81.67% specificity, which proves the reliability of the algorithm. © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

Progress towards MODIS and VIIRS Cloud Fraction Data Record Continuity

NASA Astrophysics Data System (ADS)

Ackerman, S. A.; Frey, R.; Holz, R.; Platnick, S. E.; Heidinger, A. K.

2016-12-01

Satellite-derived clear-sky vs. cloudy-sky discrimination at the pixel scale is an important input parameter used in many real-time applications. Cloud fractions, resulting from integrating over time and space, are also critical to the study of recent decadal climate changes. The NASA NPOESS Preparatory Project (NPP) has funded a science team to develop and study the ability to make continuous climate records from MODIS (2000-2020) and VIIRS (2012-2030). The MODAWG project, led by Dr. Steve Platnick of NASA/GSFC, combines elements of the MODIS processing system and the NOAA Algorithm Working Group (AWG) to achieve this goal. This presentation will focus on the cloud masking aspects of MODAWG, derived primarily from the MODIS cloud mask (MOD35). Challenges to continuity of cloud detection due to differences in instrument characteristics will be discussed. Cloud mask results from use of the same (continuity) algorithm will be shown for both MODIS and VIIRS, including comparisons to collocated CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) cloud data.

Propagation of resist heating mask error to wafer level

NASA Astrophysics Data System (ADS)

Babin, S. V.; Karklin, Linard

2006-10-01

As technology is approaching 45 nm and below the IC industry is experiencing a severe product yield hit due to rapidly shrinking process windows and unavoidable manufacturing process variations. Current EDA tools are unable by their nature to deliver optimized and process-centered designs that call for 'post design' localized layout optimization DFM tools. To evaluate the impact of different manufacturing process variations on final product it is important to trace and evaluate all errors through design to manufacturing flow. Photo mask is one of the critical parts of this flow, and special attention should be paid to photo mask manufacturing process and especially to mask tight CD control. Electron beam lithography (EBL) is a major technique which is used for fabrication of high-end photo masks. During the writing process, resist heating is one of the sources for mask CD variations. Electron energy is released in the mask body mainly as heat, leading to significant temperature fluctuations in local areas. The temperature fluctuations cause changes in resist sensitivity, which in turn leads to CD variations. These CD variations depend on mask writing speed, order of exposure, pattern density and its distribution. Recent measurements revealed up to 45 nm CD variation on the mask when using ZEP resist. The resist heating problem with CAR resists is significantly smaller compared to other types of resists. This is partially due to higher resist sensitivity and the lower exposure dose required. However, there is no data yet showing CD errors on the wafer induced by CAR resist heating on the mask. This effect can be amplified by high MEEF values and should be carefully evaluated at 45nm and below technology nodes where tight CD control is required. In this paper, we simulated CD variation on the mask due to resist heating; then a mask pattern with the heating error was transferred onto the wafer. So, a CD error on the wafer was evaluated subject to only one term of the mask error budget - the resist heating CD error. In simulation of exposure using a stepper, variable MEEF was considered.

Analysis of the VIIRS cloud mask, comparison with the NAVOCEANO cloud mask, and how they complement each other

NASA Astrophysics Data System (ADS)

Cayula, Jean-François P.; May, Douglas A.; McKenzie, Bruce D.

2014-05-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) Cloud Mask (VCM) Intermediate Product (IP) has been developed for use with Suomi National Polar-orbiting Partnership (NPP) VIIRS Environmental Data Record (EDR) products. In particular, the VIIRS Sea Surface Temperature (SST) EDR relies on VCM to identify cloud contaminated observations. Unfortunately, VCM does not appear to perform as well as cloud detection algorithms for SST. This may be due to similar but different goals of the two algorithms. VCM is concerned with detecting clouds while SST is interested in identifying clear observations. The result is that in undetermined cases VCM defaults to "clear," while the SST cloud detection defaults to "cloud." This problem is further compounded because classic SST cloud detection often flags as "cloud" all types of corrupted data, thus making a comparison with VCM difficult. The Naval Oceanographic Office (NAVOCEANO), which operationally produces a VIIRS SST product, relies on cloud detection from the NAVOCEANO Cloud Mask (NCM), adapted from cloud detection schemes designed for SST processing. To analyze VCM, the NAVOCEANO SST process was modified to attach the VCM flags to all SST retrievals. Global statistics are computed for both day and night data. The cases where NCM and/or VCM tag data as cloud-contaminated or clear can then be investigated. By analyzing the VCM individual test flags in conjunction with the status of NCM, areas where VCM can complement NCM are identified.

The pinwheel pupil discovery: exoplanet science & improved processing with segmented telescopes

NASA Astrophysics Data System (ADS)

Breckinridge, James Bernard

2018-01-01

In this paper, we show that by using a “pinwheel” architecture for the segmented primary mirror and curved supports for the secondary mirror, we can achieve a near uniform diffraction background in ground and space large telescope systems needed for high SNR exoplanet science. Also, the point spread function will be nearly rotationally symmetric, enabling improved digital image reconstruction. Large (>4-m) aperture space telescopes are needed to characterize terrestrial exoplanets by direct imaging coronagraphy. Launch vehicle volume constrains these apertures are segmented and deployed in space to form a large mirror aperture that is masked by the gaps between the hexagonal segments and the shadows of the secondary support system. These gaps and shadows over the pupil result in an image plane point spread function that has bright spikes, which may mask or obscure exoplanets.These telescope artifact mask faint exoplanets, making it necessary for the spacecraft to make a roll about the boresight and integrate again to make sure no planets are missed. This increases integration time, and requires expensive space-craft resources to do bore-sight roll.Currently the LUVOIR and HabEx studies have several significant efforts to develop special purpose A/O technology and to place complex absorbing apodizers over their Hex pupils to shape the unwanted diffracted light. These strong apodizers absorb light, decreasing system transmittance and reducing SNR. Implementing curved pupil obscurations will eliminate the need for the highly absorbing apodizers and thus result in higher SNR.Quantitative analysis of diffraction patterns that use the pinwheel architecture are compared to straight hex-segment edges with a straight-line secondary shadow mask to show a gain of over a factor of 100 by reducing the background. For the first-time astronomers are able to control and minimize image plane diffraction background “noise”. This technology will enable 10-m segmented apertures to perform nearly the same as a 10-meter monolith filled aperture. The pinwheel pupil will enable a significant gain in exoplanet SNR.

Optical proximity correction for anamorphic extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

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

NASA Astrophysics Data System (ADS)

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

2008-05-01

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

Negative-tone imaging with EUV exposure toward 13nm hp

NASA Astrophysics Data System (ADS)

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

2016-03-01

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

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…

SU-8 negative photoresist for optical mask manufacturing

NASA Astrophysics Data System (ADS)

Bogdanov, Alexei L.

2000-06-01

The requirements for better control, linearity, and uniformity of critical dimension (CD) on photomasks in fabrication of 180 and 150 nm generation devices result in increasing demand for thinner, more etching durable, and more sensitive e-beam resists. Novolac based resists with chemical amplification have been a choice for their sensitivity and stability during etching. However, difficult CD control due to the acid catalyzer diffusion and quite narrow post exposure bake (PEB) process window are some of the major drawbacks of these resists. SU-8 is recently introduced to the market negative photoresist. High sensitivity, fairly good adhesion properties, and relatively simple processing of SU-8 make it a good substitution for novolac based chemically amplified negative e-beam resists in optical mask manufacturing. The replacement of traditional chemically amplified resists by SU- 8 can increase the process latitude and reduce resist costs. Among the obvious drawbacks of SU-8 are the use of solvent- based developer and demand of oxygen plasma for resist removal. In this paper the use of SU-8 for optical mask manufacturing is reported. All steps of resist film preparation, exposure and development are paid a share of attention. Possibilities to use reactive ion etching (RIE) with oxygen in order to increase resist mask contrast are discussed. Special exposure strategy (pattern outlining) was employed to further improve the edge definition. The resist PEB temperature and time were studied to estimate their weight in overall CD control performance. Specially designed test patterns with 0.25 micrometer design rule could be firmly transferred into a chromium layer both by wet etching and ion milling. Influence of exposure dose variation on the pattern CD change was studied.

Interactions between concentric form-from-structure and face perception revealed by visual masking but not adaptation

PubMed Central

Feczko, Eric; Shulman, Gordon L.; Petersen, Steven E.; Pruett, John R.

2014-01-01

Findings from diverse subfields of vision research suggest a potential link between high-level aspects of face perception and concentric form-from-structure perception. To explore this relationship, typical adults performed two adaptation experiments and two masking experiments to test whether concentric, but not nonconcentric, Glass patterns (a type of form-from-structure stimulus) utilize a processing mechanism shared by face perception. For the adaptation experiments, subjects were presented with an adaptor for 5 or 20 s, prior to discriminating a target. In the masking experiments, subjects saw a mask, then a target, and then a second mask. Measures of discriminability and bias were derived and repeated measures analysis of variance tested for pattern-specific masking and adaptation effects. Results from Experiment 1 show no Glass pattern-specific effect of adaptation to faces; results from Experiment 2 show concentric Glass pattern masking, but not adaptation, may impair upright/inverted face discrimination; results from Experiment 3 show concentric and radial Glass pattern masking impaired subsequent upright/inverted face discrimination more than translational Glass pattern masking; and results from Experiment 4 show concentric and radial Glass pattern masking impaired subsequent face gender discrimination more than translational Glass pattern masking. Taken together, these findings demonstrate interactions between concentric form-from-structure and face processing, suggesting a possible common processing pathway. PMID:24563526

Conceptual Masking: How One Picture Captures Attention from Another Picture.

ERIC Educational Resources Information Center

Loftus, Geoffrey R.; And Others

1988-01-01

Five experiments studied operations of conceptual masking--the reduction of conceptual memory performance for an initial stimulus when it is followed by a masking picture process. The subjects were 337 undergraduates at the University of Washington (Seattle). Conceptual masking is distinguished from perceptual masking. (TJH)

Force-dependent static dead space of face masks used with holding chambers.

PubMed

Shah, Samir A; Berlinski, Ariel B; Rubin, Bruce K

2006-02-01

Pressurized metered-dose inhalers with valved holding chambers and masks are commonly used for aerosol delivery in children. Drug delivery can decrease when the dead-space volume (DSV) of the valved holding chamber is increased, but there are no published data evaluating force-dependent DSV among different masks. Seven masks were studied. Masks were sealed at the valved holding chamber end and filled with water to measure mask volume. To measure mask DSV we used a mannequin of 2-year-old-size face and we applied the mask with forces of 1.5, 3.5, and 7 pounds. Mask seal was determined by direct observation. Intra-brand analysis was done via analysis of variance. At 3.5 pounds of force, the DSV ranged from 29 mL to 100 mL, with 3 masks having DSV of < 50 mL. The remaining masks all had DSV > 60 mL. At 3.5 pounds of force, DSV percent of mask volume ranged from 33.7% (Aerochamber, p < 0.01 compared with other masks) to 100% (Pocket Chamber). DSV decreased with increasing force with most of the masks, and the slope of this line was inversely proportional to mask flexibility. Mask fit was 100% at 1.5 pounds of force only with the Aerochamber and Optichamber. Mask fit was poorest with the Vortex, Pocket Chamber, and BreatheRite masks. Rigid masks with large DSV might not be not suitable for use in children, especially if discomfort from the stiff mask makes its use less acceptable to the child.

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

PubMed

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

2017-11-01

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

300 nm bandwidth adiabatic SOI polarization splitter-rotators exploiting continuous symmetry breaking.

PubMed

Socci, Luciano; Sorianello, Vito; Romagnoli, Marco

2015-07-27

Adiabatic polarization splitter-rotators are investigated exploiting continuous symmetry breaking thereby achieving significant device size and losses reduction in a single mask fabrication process for both SOI channel and ridge waveguides. A crosstalk lower than -25 dB is expected over 300nm bandwidth, making the device suitable for full grid CWDM and diplexer/triplexer FTTH applications at 1310, 1490 and 1550nm.

Design architecture of double spiral interdigitated electrode with back gate electrode for biosensor application

NASA Astrophysics Data System (ADS)

Fathil, M. F. M.; Arshad, M. K. Md.; Hashim, U.; Ruslinda, A. R.; Gopinath, Subash C. B.; M. Nuzaihan M., N.; Ayub, R. M.; Adzhri, R.; Zaki, M.; Azman, A. H.

2016-07-01

This paper presents the preparation method of photolithography chrome mask design used in fabrication process of double spiral interdigitated electrode with back gate biasing based biosensor. By learning the fabrication process flow of the biosensor, the chrome masks are designed through drawing using the AutoCAD software. The overall width and length of the device is optimized at 7.0 mm and 10.0 mm, respectively. Fabrication processes of the biosensor required three chrome masks, which included back gate opening, spiral IDE formation, and passivation area formation. The complete chrome masks design will be sent for chrome mask fabrication and for future use in biosensor fabrication.

Reentrant processing mediates object substitution masking: comment on Põder (2013).

PubMed

Di Lollo, Vincent

2014-01-01

Object-substitution masking (OSM) occurs when a target stimulus and a surrounding mask are displayed briefly together, and the display then continues with the mask alone. Target identification is accurate when the stimuli co-terminate but is progressively impaired as the duration of the trailing mask is increased. In reentrant accounts, OSM is said to arise from iterative exchanges between brain regions connected by two-way pathways. In an alternative account, OSM is explained on the basis of exclusively feed-forward processes, without recourse to reentry. Here I show that the feed-forward account runs afoul of the extant phenomenological, behavioral, brain-imaging, and electrophysiological evidence. Further, the feed-forward assumption that masking occurs when attention finds a degraded target is shown to be entirely ad hoc. In contrast, the evidence is uniformly consistent with a reentrant-processing account of OSM.

Inexpensive Masks for Film Deposition

NASA Technical Reports Server (NTRS)

Conley, W. R.

1986-01-01

Sputtered sprayed lines less than 2 millimeters wide made by superimposing masks with partially overlapping openings. Slits first cut in masks by stamping or other economical process. Masks superimposed so slits define new openings narrower than original slits.

"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…

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 contaminants: by inline techniques based on Adixen humidity, also VOC and organic sensors, together by off-line techniques already used in the extensive previous mask pods benchmark (TD-GCMS & Ionic Chromatography). Humidity and VOC levels from mask carriers had shown significant reduction after Adixen pod conditioning process. Focus had been made on optimized vacuum step (for AMC) after particles carrier cleaning cycle. Based upon these key results new procedures, as well as guidelines for mask carrier cleaning optimization are proposed to improve pod contamination control. Summary results/next steps: This paper reports molecular contamination measurement campaigns performed by a pool of European partners along the mask supply chain. It allows us to investigate, identify and quantify critical molecular contamination in mask pod, as well as VOC and humidity, issues depending on locations, uses, and carrier's type. Preliminary studies highlight initial process solutions for pods conditioning that are being used for short term industrialization and further industrialized.

Challenges and requirements of mask data processing for multi-beam mask writer

NASA Astrophysics Data System (ADS)

Choi, Jin; Lee, Dong Hyun; Park, Sinjeung; Lee, SookHyun; Tamamushi, Shuichi; Shin, In Kyun; Jeon, Chan Uk

2015-07-01

To overcome the resolution and throughput of current mask writer for advanced lithography technologies, the platform of e-beam writer have been evolved by the developments of hardware and software in writer. Especially, aggressive optical proximity correction (OPC) for unprecedented extension of optical lithography and the needs of low sensitivity resist for high resolution result in the limit of variable shaped beam writer which is widely used for mass production. The multi-beam mask writer is attractive candidate for photomask writing of sub-10nm device because of its high speed and the large degree of freedom which enable high dose and dose modulation for each pixel. However, the higher dose and almost unlimited appetite for dose modulation challenge the mask data processing (MDP) in aspects of extreme data volume and correction method. Here, we discuss the requirements of mask data processing for multi-beam mask writer and presents new challenges of the data format, data flow, and correction method for user and supplier MDP tool.

Pattern Inspection of EUV Masks Using DUV Light

NASA Astrophysics Data System (ADS)

Liang, Ted; Tejnil, Edita; Stivers, Alan R.

2002-12-01

Inspection of extreme ultraviolet (EUV) lithography masks requires reflected light and this poses special challenges for inspection tool suppliers as well as for mask makers. Inspection must detect all the printable defects in the absorber pattern as well as printable process-related defects. Progress has been made under the NIST ATP project on "Intelligent Mask Inspection Systems for Next Generation Lithography" in assessing the factors that impact the inspection tool sensitivity. We report in this paper the inspection of EUV masks with programmed absorber defects using 257nm light. All the materials of interests for masks are highly absorptive to EUV light as compared to deep ultraviolet (DUV) light. Residues and contamination from mask fabrication process and handling are prone to be printable. Therefore, it is critical to understand their EUV printability and optical inspectability. Process related defects may include residual buffer layer such as oxide, organic contaminants and possible over-etch to the multilayer surface. Both simulation and experimental results will be presented in this paper.

Fabrication of a novel quartz micromachined gyroscope

NASA Astrophysics Data System (ADS)

Xie, Liqiang; Xing, Jianchun; Wang, Haoxu; Wu, Xuezhong

2015-04-01

A novel quartz micromachined gyroscope is proposed in this paper. The novel gyroscope is realized by quartz anisotropic wet etching and 3-dimensional electrodes deposition. In the quartz wet etching process, the quality of Cr/Au mask films affecting the process are studied by experiment. An excellent mask film with 100 Å Cr and 2000 Å Au is achieved by optimization of experimental parameters. Crystal facets after etching seriously affect the following sidewall electrodes deposition process and the structure's mechanical behaviours. Removal of crystal facets is successfully implemented by increasing etching time based on etching rate ratios between facets and crystal planes. In the electrodes deposition process, an aperture mask evaporation method is employed to prepare electrodes on 3-dimensional surfaces of the gyroscope structure. The alignments among the aperture masks are realized by the ABM™ Mask Aligner System. Based on the processes described above, a z-axis quartz gyroscope is fabricated successfully.

Functional neuroanatomy of visual masking deficits in schizophrenia.

PubMed

Green, Michael F; Lee, Junghee; Cohen, Mark S; Engel, Steven A; Korb, Alexander S; Nuechterlein, Keith H; Wynn, Jonathan K; Glahn, David C

2009-12-01

Visual masking procedures assess the earliest stages of visual processing. Patients with schizophrenia reliably show deficits on visual masking, and these procedures have been used to explore vulnerability to schizophrenia, probe underlying neural circuits, and help explain functional outcome. To identify and compare regional brain activity associated with one form of visual masking (ie, backward masking) in schizophrenic patients and healthy controls. Subjects received functional magnetic resonance imaging scans. While in the scanner, subjects performed a backward masking task and were given 3 functional localizer activation scans to identify early visual processing regions of interest (ROIs). University of California, Los Angeles, and the Department of Veterans Affairs Greater Los Angeles Healthcare System. Nineteen patients with schizophrenia and 19 healthy control subjects. Main Outcome Measure The magnitude of the functional magnetic resonance imaging signal during backward masking. Two ROIs (lateral occipital complex [LO] and the human motion selective cortex [hMT+]) showed sensitivity to the effects of masking, meaning that signal in these areas increased as the target became more visible. Patients had lower activation than controls in LO across all levels of visibility but did not differ in other visual processing ROIs. Using whole-brain analyses, we also identified areas outside the ROIs that were sensitive to masking effects (including bilateral inferior parietal lobe and thalamus), but groups did not differ in signal magnitude in these areas. The study results support a key role in LO for visual masking, consistent with previous studies in healthy controls. The current results indicate that patients fail to activate LO to the same extent as controls during visual processing regardless of stimulus visibility, suggesting a neural basis for the visual masking deficit, and possibly other visual integration deficits, in schizophrenia.

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.

Flat-Sky Pseudo-Cls Analysis for Weak Gravitational Lensing

NASA Astrophysics Data System (ADS)

Asgari, Marika; Taylor, Andy; Joachimi, Benjamin; Kitching, Thomas D.

2018-05-01

We investigate the use of estimators of weak lensing power spectra based on a flat-sky implementation of the 'Pseudo-CI' (PCl) technique, where the masked shear field is transformed without regard for masked regions of sky. This masking mixes power, and 'E'-convergence and 'B'-modes. To study the accuracy of forward-modelling and full-sky power spectrum recovery we consider both large-area survey geometries, and small-scale masking due to stars and a checkerboard model for field-of-view gaps. The power spectrum for the large-area survey geometry is sparsely-sampled and highly oscillatory, which makes modelling problematic. Instead, we derive an overall calibration for large-area mask bias using simulated fields. The effects of small-area star masks can be accurately corrected for, while the checkerboard mask has oscillatory and spiky behaviour which leads to percent biases. Apodisation of the masked fields leads to increased biases and a loss of information. We find that we can construct an unbiased forward-model of the raw PCls, and recover the full-sky convergence power to within a few percent accuracy for both Gaussian and lognormal-distributed shear fields. Propagating this through to cosmological parameters using a Fisher-Matrix formalism, we find we can make unbiased estimates of parameters for surveys up to 1,200 deg2 with 30 galaxies per arcmin2, beyond which the percent biases become larger than the statistical accuracy. This implies a flat-sky PCl analysis is accurate for current surveys but a Euclid-like survey will require higher accuracy.

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

NASA Astrophysics Data System (ADS)

Kimmel, Kurt R.; Hughes, Patrick J.

1996-05-01

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

Paving the way to a full chip gate level double patterning application

NASA Astrophysics Data System (ADS)

Haffner, Henning; Meiring, Jason; Baum, Zachary; Halle, Scott

2007-10-01

Double patterning lithography processes can offer significant yield enhancement for challenging circuit designs. Many decomposition (i.e. the process of dividing the layout design into first and second exposures) techniques are possible, but the focus of this paper is on the use of a secondary "cut" mask to trim away extraneous features left from the first exposure. This approach has the advantage that each exposure only needs to support a subset of critical features (e.g. dense lines with the first exposure, isolated spaces with the second one). The extraneous features ("printing assist features" or PrAFs) are designed to support the process window of critical features much like the role of the subresolution assist features (SRAFs) in conventional processes. However, the printing nature of PrAFs leads to many more design options, and hence a greater process and decomposition parameter exploration space, than are available for SRAFs. A decomposition scheme using PRAFs was developed for a gate level process. A critical driver of the work was to deliver improved across-chip linewidth variation (ACLV) performance versus an optimized single exposure process while providing support for a larger range of critical features. A variety of PRAF techniques were investigated by simulation, with a PrAF scheme similar to standard SRAF rules being chosen as the optimal solution [1]. This paper discusses aspects of the code development for an automated PrAF generation and placement scheme and the subsequent decomposition of a layout into two mask levels. While PrAF placement and decomposition is straightforward for layouts with pitch and orientation restrictions, it becomes rather complex for unrestricted layout styles. Because this higher complexity yields more irregularly shaped PrAFs, mask making becomes another critical driver of the optimum placement and clean-up strategies. Examples are given of how those challenges are met or can be successfully circumvented. During subsequent decomposition of the PrAF-enhanced layout into two independent mask levels, various geometric decomposition parameters have to be considered. As an example, the removal of PrAFs has to be guaranteed by a minimum required overlap of the cut mask opening past any PrAF edge. It is discussed that process assumptions such as CD tolerances and overlay as well as inter-level relationship ground rules need to be considered to successfully optimize the final decomposition scheme. Furthermore, simulation and experimental results regarding not only ACLV but also across-device linewidth variation (ADLV) are analyzed.

Optical proximity correction for anamorphic extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Reinforced Masks for Ion Plating of Solar Cells

NASA Technical Reports Server (NTRS)

Conley, W. R.; Swick, E. G.; Volkers, J. C.

1987-01-01

Proposed mask for ion plating of surface electrodes on silicon solar cells reinforced to hold shape better during handling. Fabrication process for improved mask similar to conventional mask. Additional cuts and bends made in wide diametral strip to form bridges between pairs of mask fingers facing each other across this strip. Bridges high enough not to act as masks so entire strip area plated.

Full-chip level MEEF analysis using model based lithography verification

NASA Astrophysics Data System (ADS)

Kim, Juhwan; Wang, Lantian; Zhang, Daniel; Tang, Zongwu

2005-11-01

MEEF (Mask Error Enhancement Factor) has become a critical factor in CD uniformity control since optical lithography process moved to sub-resolution era. A lot of studies have been done by quantifying the impact of the mask CD (Critical Dimension) errors on the wafer CD errors1-2. However, the benefits from those studies were restricted only to small pattern areas of the full-chip data due to long simulation time. As fast turn around time can be achieved for the complicated verifications on very large data by linearly scalable distributed processing technology, model-based lithography verification becomes feasible for various types of applications such as post mask synthesis data sign off for mask tape out in production and lithography process development with full-chip data3,4,5. In this study, we introduced two useful methodologies for the full-chip level verification of mask error impact on wafer lithography patterning process. One methodology is to check MEEF distribution in addition to CD distribution through process window, which can be used for RET/OPC optimization at R&D stage. The other is to check mask error sensitivity on potential pinch and bridge hotspots through lithography process variation, where the outputs can be passed on to Mask CD metrology to add CD measurements on those hotspot locations. Two different OPC data were compared using the two methodologies in this study.

Strategy optimization for mask rule check in wafer fab

NASA Astrophysics Data System (ADS)

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

2015-07-01

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

New Y2K problem for mask making (or, Surviving mask data problems after 2000)

NASA Astrophysics Data System (ADS)

Sturgeon, Roger

1999-08-01

The Y2K problem has analogies in the mask-making world. With the Y2K problem where a date field has just two bytes for the year, there are some cases of mask-making data in which the file size cannot exceed 2 gigabytes. Where a two-digit date field can only unambiguously use a limited range of values (00 to 99), design coordinates can only cover a range of about 4 billion values, which is getting a little uncomfortable for all of the new applications. In retrospect, with a degree of foresight and planning the Y2K date problem could have been easily solved if new encodings had been allowed in the two- digit field. Likewise, in the mask-making industry we currently have the opportunity to achieve far superior data compression if we allow some new forms of data encoding in our data. But this will require universal agreement. The correct way to look at the Y2K problem is that some information was left out of the data stream due to common understandings that made the additional information superfluous. But as the year 2000 approaches, it has become widely recognized that missing data needs to be stated explicitly, and any ambiguities in the representation of the data will need to be eliminated with precise specifications. In a similar way, old mask data generation methods have had numerous flaws that we have been able to ignore for a long time. But now is the time to fix theses flaws and provide extended capabilities. What is not yet clear is if the old data generation methods can be modified to meet these developing needs. Unilateral action is not likely to lead to much progress, so some united effort is required by all interested parties if success is to be achieved in the brief time that remains.

SEMATECH produces defect-free EUV mask blanks: defect yield and immediate challenges

NASA Astrophysics Data System (ADS)

Antohe, Alin O.; Balachandran, Dave; He, Long; Kearney, Patrick; Karumuri, Anil; Goodwin, Frank; Cummings, Kevin

2015-03-01

Availability of defect-free reflective mask has been one of the most critical challenges to extreme ultraviolet lithography (EUVL). To mitigate the risk, significant progress has been made on defect detection, pattern shifting, and defect repair. Clearly such mitigation strategies are based on the assumption that defect counts and sizes from incoming mask blanks must be below practical levels depending on mask specifics. The leading industry consensus for early mask product development is that there should be no defects greater than 80 nm in the quality area, 132 mm x 132 mm. In addition less than 10 defects smaller than 80 nm may be mitigable. SEMATECH has been focused on EUV mask blank defect reduction using Veeco Nexus TM IBD platform, the industry standard for mask blank production, and assessing if IBD technology can be evolved to a manufacturing solution. SEMATECH has recently announced a breakthrough reduction of defects in the mask blank deposition process resulting in the production of two defect-free EUV mask blanks at 54 nm inspection sensitivity (SiO2 equivalent). This paper will discuss the dramatic reduction of baseline EUV mask blank defects, review the current deposition process run and compare results with previous process runs. Likely causes of remaining defects will be discussed based on analyses as characterized by their compositions and whether defects are embedded in the multilayer stack or non-embedded.

Machine learning for inverse lithography: using stochastic gradient descent for robust photomask synthesis

NASA Astrophysics Data System (ADS)

Jia, Ningning; Y Lam, Edmund

2010-04-01

Inverse lithography technology (ILT) synthesizes photomasks by solving an inverse imaging problem through optimization of an appropriate functional. Much effort on ILT is dedicated to deriving superior masks at a nominal process condition. However, the lower k1 factor causes the mask to be more sensitive to process variations. Robustness to major process variations, such as focus and dose variations, is desired. In this paper, we consider the focus variation as a stochastic variable, and treat the mask design as a machine learning problem. The stochastic gradient descent approach, which is a useful tool in machine learning, is adopted to train the mask design. Compared with previous work, simulation shows that the proposed algorithm is effective in producing robust masks.

Brightness masking is modulated by disparity structure.

PubMed

Pelekanos, Vassilis; Ban, Hiroshi; Welchman, Andrew E

2015-05-01

The luminance contrast at the borders of a surface strongly influences surface's apparent brightness, as demonstrated by a number of classic visual illusions. Such phenomena are compatible with a propagation mechanism believed to spread contrast information from borders to the interior. This process is disrupted by masking, where the perceived brightness of a target is reduced by the brief presentation of a mask (Paradiso & Nakayama, 1991), but the exact visual stage that this happens remains unclear. In the present study, we examined whether brightness masking occurs at a monocular-, or a binocular-level of the visual hierarchy. We used backward masking, whereby a briefly presented target stimulus is disrupted by a mask coming soon afterwards, to show that brightness masking is affected by binocular stages of the visual processing. We manipulated the 3-D configurations (slant direction) of the target and mask and measured the differential disruption that masking causes on brightness estimation. We found that the masking effect was weaker when stimuli had a different slant. We suggest that brightness masking is partly mediated by mid-level neuronal mechanisms, at a stage where binocular disparity edge structure has been extracted. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Masking Level Difference Response Norms from Learning Disabled Individuals.

ERIC Educational Resources Information Center

Waryas, Paul A.; Battin, R. Ray

1985-01-01

The study presents normative data on Masking Level Difference (an improvement of the auditory processing of interaural time/intensity differences between signals and masking noises) for 90 learning disabled persons (4-35 years old). It was concluded that the MLD may quickly screen for auditory processing problems. (CL)

Masked Speech Recognition and Reading Ability in School-Age Children: Is There a Relationship?

ERIC Educational Resources Information Center

Miller, Gabrielle; Lewis, Barbara; Benchek, Penelope; Buss, Emily; Calandruccio, Lauren

2018-01-01

Purpose: The relationship between reading (decoding) skills, phonological processing abilities, and masked speech recognition in typically developing children was explored. This experiment was designed to evaluate the relationship between phonological processing and decoding abilities and 2 aspects of masked speech recognition in typically…

Evaluation of the morphology structure of meibomian glands based on mask dodging method

NASA Astrophysics Data System (ADS)

Yan, Huangping; Zuo, Yingbo; Chen, Yisha; Chen, Yanping

2016-10-01

Low contrast and non-uniform illumination of infrared (IR) meibography images make the detection of meibomian glands challengeable. An improved Mask dodging algorithm is proposed. To overcome the shortage of low contrast using traditional Mask dodging method, a scale factor is used to enhance the image after subtracting background image from an original one. Meibomian glands are detected and the ratio of the meibomian gland area to the measurement area is calculated. The results show that the improved Mask algorithm has ideal dodging effect, which can eliminate non-uniform illumination and improve contrast of meibography images effectively.

Visual Masking in Schizophrenia: Overview and Theoretical Implications

PubMed Central

Green, Michael F.; Lee, Junghee; Wynn, Jonathan K.; Mathis, Kristopher I.

2011-01-01

Visual masking provides several key advantages for exploring the earliest stages of visual processing in schizophrenia: it allows for control over timing at the millisecond level, there are several well-supported theories of the underlying neurobiology of visual masking, and it is amenable to examination by electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI). In this paper, we provide an overview of the visual masking impairment schizophrenia, including the relevant theoretical mechanisms for masking impairment. We will discuss its relationship to clinical symptoms, antipsychotic medications, diagnostic specificity, and presence in at-risk populations. As part of this overview, we will cover the neural correlates of visual masking based on recent findings from EEG and fMRI. Finally, we will suggest a possible mechanism that could explain the patterns of masking findings and other visual processing findings in schizophrenia. PMID:21606322

Single closed contact for 0.18-micron photolithography process

NASA Astrophysics Data System (ADS)

Cheung, Cristina; Phan, Khoi A.; Chiu, Robert J.

2000-06-01

With the rapid advances of deep submicron semiconductor technology, identifying defects is converted into a challenge for different modules in the fabrication of chips. Yield engineers often do bitmap on a memory circuit array (SRAM) to identify the failure bits. This is followed by a wafer stripback to look for visual defects at each deprocessed layer for feedback to the Fab. However, to identify the root cause of a problem, Fab engineers must be able to detect similar defects either on the product wafers in process or some short loop test wafers. In the photolithography process, we recognize that the detection of defects is becoming as important as satisfying the critical dimension (CD) of the device. For a multi-level metallization chemically mechanical polish backend process, it is very difficult to detect missing contacts or via at the masking steps due to metal grain roughness, film color variation and/or previous layer defects. Often, photolithography engineer must depend on Photo Cell Monitor (PCM) and short loop experiments for controlling baseline defects and improvement. In this paper, we discuss the findings on the Poly mask PCM and the Contact mask PCM. We present the comparison between the Poly mask and the Contact mask of the I-line Phase Shifted Via mask and DUV mask process for a 0.18 micron process technology. The correlation and the different type of defects between the Contact PCM and the Poly Mask are discussed. The Contact PCM was found to be more sensitive and correlated to contact failure at sort yield better. We also dedicate to study the root cause of a single closed contact hole in the Contact mask short loop experiment for a 0.18 micron process technology. A single closed contact defect was often caused by the developer process, such as bubbles in the line, resist residue left behind, and the rinse mechanism. We also found surfactant solution helps to improve the surface tension of the wafer for the developer process and this prevents/eliminates a single closed contact hole defects. The applications and effects of using different substrates like SiON, different thicknesses of Oxides, and Poly in the Contact Photo Mask is shown. Finally, some defect troubleshooting techniques and the root cause analysis are also discussed.

Application of advanced structure to multi-tone mask for FPD process

NASA Astrophysics Data System (ADS)

Song, Jin-Han; Jeong, Jin-Woong; Kim, Kyu-Sik; Jeong, Woo-Gun; Yun, Sang-Pil; Lee, Dong-Heok; Choi, Sang-Soo

2017-07-01

In accordance with improvement of FPD technology, masks such as phase shift mask (PSM) and multi-tone mask (MTM) for a particular purpose also have been developed. Above all, the MTM consisted of more than tri-tone transmittance has a substantial advantage which enables to reduce the number of mask demand in FPD fabrication process contrast to normal mask of two-tone transmittance.[1,2] A chromium (Cr)-based MTM (Typically top type) is being widely employed because of convenience of etch process caused by its only Cr-based structure consisted of Cr absorber layer and Cr half-tone layer. However, the top type of Cr-based MTM demands two Cr sputtering processes after each layer etching process and writing process. For this reason, a different material from the Cr-based MTM is required for reduction of mask fabrication time and cost. In this study, we evaluate a MTM which has a structure combined Cr with molybdenum silicide (MoSi) to resolve the issues mentioned above. The MoSi which is demonstrated by integrated circuit (IC) process is a suitable material for MTM evaluation. This structure could realize multi-transmittance in common with the Cr-based MTM. Moreover, it enables to reduce the number of sputtering process. We investigate a optimized structure upon consideration of productivity along with performance such as critical dimension (CD) variation and transmittance range of each structure. The transmittance is targeted at h-line wavelength (405 nm) in the evaluation. Compared with Cr-based MTM, the performances of all Cr-/MoSi-based MTMs are considered.

Quartz 9-inch size mask blanks for ArF PSM (Phase Shift Mask)

NASA Astrophysics Data System (ADS)

Harashima, Noriyuki; Isozaki, Tatsuya; Kawanishi, Arata; Kanai, Shuichiro; Kageyama, Kagehiro; Iso, Hiroyuki; Chishima, Tatsuya

2017-07-01

Semiconductor technology nodes are steadily miniaturizing. On the other hand, various efforts have been made to reduce costs, mass production lines have shifted from 200 mmφ of Si wafer to 300 mmφ, and technology development of Si wafer 450 mmφ is also in progress. As a photomask, 6-inch size binary Cr mask has been used for many years, but in recent years, the use of 9-inch binary Cr masks for Proximity Lithography Process in automotive applications, MEMS, packages, etc. has increased, and cost reduction has been taken. Since the miniaturization will progress in the above applications in the future, products corresponding to miniaturization are also desired in 9-inch photomasks. The high grade Cr - binary mask blanks used in proximity exposure process, there is a prospect of being able to use it by ULVAC COATING CORPORATION's tireless research. As further demands for miniaturization, KrF and ArF Lithography Process, which are used for steppers and scanners , there are also a demand for 9-inch size Mask Blanks. In ULVAC COATING CORPORATION, we developed a 9 - inch size KrF PSM mask Blanks prototype in 2016 and proposed a new high grade 9 - inch photomask. This time, we have further investigated and developed 9-inch size ArF PSM Mask Blanks corresponding to ArF Lithography Process, so we report it.

Discrimination in lexical decision

PubMed Central

Feldman, Laurie Beth; Ramscar, Michael; Hendrix, Peter; Baayen, R. Harald

2017-01-01

In this study we present a novel set of discrimination-based indicators of language processing derived from Naive Discriminative Learning (ndl) theory. We compare the effectiveness of these new measures with classical lexical-distributional measures—in particular, frequency counts and form similarity measures—to predict lexical decision latencies when a complete morphological segmentation of masked primes is or is not possible. Data derive from a re-analysis of a large subset of decision latencies from the English Lexicon Project, as well as from the results of two new masked priming studies. Results demonstrate the superiority of discrimination-based predictors over lexical-distributional predictors alone, across both the simple and primed lexical decision tasks. Comparable priming after masked corner and cornea type primes, across two experiments, fails to support early obligatory segmentation into morphemes as predicted by the morpho-orthographic account of reading. Results fit well with ndl theory, which, in conformity with Word and Paradigm theory, rejects the morpheme as a relevant unit of analysis. Furthermore, results indicate that readers with greater spelling proficiency and larger vocabularies make better use of orthographic priors and handle lexical competition more efficiently. PMID:28235015

Discrimination in lexical decision.

PubMed

Milin, Petar; Feldman, Laurie Beth; Ramscar, Michael; Hendrix, Peter; Baayen, R Harald

2017-01-01

In this study we present a novel set of discrimination-based indicators of language processing derived from Naive Discriminative Learning (ndl) theory. We compare the effectiveness of these new measures with classical lexical-distributional measures-in particular, frequency counts and form similarity measures-to predict lexical decision latencies when a complete morphological segmentation of masked primes is or is not possible. Data derive from a re-analysis of a large subset of decision latencies from the English Lexicon Project, as well as from the results of two new masked priming studies. Results demonstrate the superiority of discrimination-based predictors over lexical-distributional predictors alone, across both the simple and primed lexical decision tasks. Comparable priming after masked corner and cornea type primes, across two experiments, fails to support early obligatory segmentation into morphemes as predicted by the morpho-orthographic account of reading. Results fit well with ndl theory, which, in conformity with Word and Paradigm theory, rejects the morpheme as a relevant unit of analysis. Furthermore, results indicate that readers with greater spelling proficiency and larger vocabularies make better use of orthographic priors and handle lexical competition more efficiently.

Automatic processing of facial affects in patients with borderline personality disorder: associations with symptomatology and comorbid disorders.

PubMed

Donges, Uta-Susan; Dukalski, Bibiana; Kersting, Anette; Suslow, Thomas

2015-01-01

Instability of affects and interpersonal relations are important features of borderline personality disorder (BPD). Interpersonal problems of individuals suffering from BPD might develop based on abnormalities in the processing of facial affects and high sensitivity to negative affective expressions. The aims of the present study were to examine automatic evaluative shifts and latencies as a function of masked facial affects in patients with BPD compared to healthy individuals. As BPD comorbidity rates for mental and personality disorders are high, we investigated also the relationships of affective processing characteristics with specific borderline symptoms and comorbidity. Twenty-nine women with BPD and 38 healthy women participated in the study. The majority of patients suffered from additional Axis I disorders and/or additional personality disorders. In the priming experiment, angry, happy, neutral, or no facial expression was briefly presented (for 33 ms) and masked by neutral faces that had to be evaluated. Evaluative decisions and response latencies were registered. Borderline-typical symptomatology was assessed with the Borderline Symptom List. In the total sample, valence-congruent evaluative shifts and delays of evaluative decision due to facial affect were observed. No between-group differences were obtained for evaluative decisions and latencies. The presence of comorbid anxiety disorders was found to be positively correlated with evaluative shifting owing to masked happy primes, regardless of baseline-neutral or no facial expression condition. The presence of comorbid depressive disorder, paranoid personality disorder, and symptoms of social isolation and self-aggression were significantly correlated with response delay due to masked angry faces, regardless of baseline. In the present affective priming study, no abnormalities in the automatic recognition and processing of facial affects were observed in BPD patients compared to healthy individuals. The presence of comorbid anxiety disorders could make patients more susceptible to the influence of a happy expression on judgment processes at an automatic processing level. Comorbid depressive disorder, paranoid personality disorder, and symptoms of social isolation and self-aggression may enhance automatic attention allocation to threatening facial expressions in BPD. Increased automatic vigilance for social threat stimuli might contribute to affective instability and interpersonal problems in specific patients with BPD.

An Asymmetric Image Encryption Based on Phase Truncated Hybrid Transform

NASA Astrophysics Data System (ADS)

Khurana, Mehak; Singh, Hukum

2017-09-01

To enhance the security of the system and to protect it from the attacker, this paper proposes a new asymmetric cryptosystem based on hybrid approach of Phase Truncated Fourier and Discrete Cosine Transform (PTFDCT) which adds non linearity by including cube and cube root operation in the encryption and decryption path respectively. In this cryptosystem random phase masks are used as encryption keys and phase masks generated after the cube operation in encryption process are reserved as decryption keys and cube root operation is required to decrypt image in decryption process. The cube and cube root operation introduced in the encryption and decryption path makes system resistant against standard attacks. The robustness of the proposed cryptosystem has been analysed and verified on the basis of various parameters by simulating on MATLAB 7.9.0 (R2008a). The experimental results are provided to highlight the effectiveness and suitability of the proposed cryptosystem and prove the system is secure.

UNMASKING MASKED HYPERTENSION: PREVALENCE, CLINICAL IMPLICATIONS, DIAGNOSIS, CORRELATES, AND FUTURE DIRECTIONS

PubMed Central

Peacock, James; Diaz, Keith M.; Viera, Anthony J.; Schwartz, Joseph E.; Shimbo, Daichi

2014-01-01

‘Masked hypertension’ is defined as having non-elevated clinic blood pressure (BP) with elevated out-of-clinic average BP, typically determined by ambulatory BP monitoring. Approximately 15–30% of adults with non-elevated clinic BP have masked hypertension. Masked hypertension is associated with increased risks of cardiovascular morbidity and mortality compared to sustained normotension (non-elevated clinic and ambulatory BP), which is similar to or approaching the risk associated with sustained hypertension (elevated clinic and ambulatory BP). The confluence of increased cardiovascular risk and a failure to be diagnosed by the conventional approach of clinic BP measurement makes masked hypertension a significant public health concern. However, many important questions remain. First, the definition of masked hypertension varies across studies. Further, the best approach in the clinical setting to exclude masked hypertension also remains unknown. It is unclear whether home BP monitoring is an adequate substitute for ambulatory BP monitoring in identifying masked hypertension. Few studies have examined the mechanistic pathways that may explain masked hypertension. Finally, scarce data are available on the best approach to treating individuals with masked hypertension. Herein, we review the current literature on masked hypertension including definition, prevalence, clinical implications, special patient populations, correlates, issues related to diagnosis, treatment, and areas for future research. PMID:24573133

Perceptual learning for speech in noise after application of binary time-frequency masks

PubMed Central

Ahmadi, Mahnaz; Gross, Vauna L.; Sinex, Donal G.

2013-01-01

Ideal time-frequency (TF) masks can reject noise and improve the recognition of speech-noise mixtures. An ideal TF mask is constructed with prior knowledge of the target speech signal. The intelligibility of a processed speech-noise mixture depends upon the threshold criterion used to define the TF mask. The study reported here assessed the effect of training on the recognition of speech in noise after processing by ideal TF masks that did not restore perfect speech intelligibility. Two groups of listeners with normal hearing listened to speech-noise mixtures processed by TF masks calculated with different threshold criteria. For each group, a threshold criterion that initially produced word recognition scores between 0.56–0.69 was chosen for training. Listeners practiced with one set of TF-masked sentences until their word recognition performance approached asymptote. Perceptual learning was quantified by comparing word-recognition scores in the first and last training sessions. Word recognition scores improved with practice for all listeners with the greatest improvement observed for the same materials used in training. PMID:23464038

A prototype urine collection device for female aircrew

NASA Technical Reports Server (NTRS)

Bisson, Roger U.; Delger, Karlyna L.

1993-01-01

Women are gaining increased access to small military cockpits. This shift has stimulated the search for practical urine containment and disposal methods for female aircrew. There are no external urine collection devices (UCD) for women that are comfortable, convenient, and leak free. We describe a prototype UCD that begins to meet this need. Materials used to make custom aviator masks were adapted to mold a perineal mask. First, a perineal cast (negative) was used to make a mold (positive). Next, a perineal mask made of wax was formed to fit the positive mold. Finally, a soft, pliable perineal mask was fabricated using the wax model as a guide. The prototype was tested for comfort, fit, and leakage. In the sitting position, less than 5 cc of urine leakage occurred with each 600 cc of urine collected. Comfort was mostly satisfactory, but ambulation was limited and the outlet design could lead to kinking and obstruction. We concluded that a perineal mask may serve as a comfortable and functional external UCD acceptable for use by females in confined environments. Changes are needed to improve comfort, fit, and urine drainage. Integration into cockpits, pressure suits, chemical defense gear, and environments where access to relief facilities is restricted is planned.

Cerebral Asymmetries in Early Orthographic and Phonological Reading Processes: Evidence from Backward Masking

ERIC Educational Resources Information Center

Halderman, Laura K.; Chiarello, Christine

2005-01-01

A lateralized backward masking paradigm was used to examine hemisphere differences in orthographic and phonological processes at an early time course of word recognition. Targets (e.g., bowl) were presented and backward masked by either pseudohomophones of the target word (orthographically and phonologically similar, e.g., BOAL), orthographically…

Dry etching technologies for reflective multilayer

NASA Astrophysics Data System (ADS)

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

2012-11-01

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

A computational engine for bringing environmental consequence analysis into aviation decision-making

DOT National Transportation Integrated Search

2010-04-21

This presentation looks at the methods for ambient masking of non-natural sounds. The masking of sounds is most effective when the masker spectrum overlaps the signal spectrum; more likely to occur if the masker is broadband in nature. Land vehicles ...

Lithographic process window optimization for mask aligner proximity lithography

NASA Astrophysics Data System (ADS)

Voelkel, Reinhard; Vogler, Uwe; Bramati, Arianna; Erdmann, Andreas; Ünal, Nezih; Hofmann, Ulrich; Hennemeyer, Marc; Zoberbier, Ralph; Nguyen, David; Brugger, Juergen

2014-03-01

We introduce a complete methodology for process window optimization in proximity mask aligner lithography. The commercially available lithography simulation software LAB from GenISys GmbH was used for simulation of light propagation and 3D resist development. The methodology was tested for the practical example of lines and spaces, 5 micron half-pitch, printed in a 1 micron thick layer of AZ® 1512HS1 positive photoresist on a silicon wafer. A SUSS MicroTec MA8 mask aligner, equipped with MO Exposure Optics® was used in simulation and experiment. MO Exposure Optics® is the latest generation of illumination systems for mask aligners. MO Exposure Optics® provides telecentric illumination and excellent light uniformity over the full mask field. MO Exposure Optics® allows the lithography engineer to freely shape the angular spectrum of the illumination light (customized illumination), which is a mandatory requirement for process window optimization. Three different illumination settings have been tested for 0 to 100 micron proximity gap. The results obtained prove, that the introduced process window methodology is a major step forward to obtain more robust processes in mask aligner lithography. The most remarkable outcome of the presented study is that a smaller exposure gap does not automatically lead to better print results in proximity lithography - what the "good instinct" of a lithographer would expect. With more than 5'000 mask aligners installed in research and industry worldwide, the proposed process window methodology might have significant impact on yield improvement and cost saving in industry.

Dry etched SiO2 Mask for HgCdTe Etching Process

NASA Astrophysics Data System (ADS)

Chen, Y. Y.; Ye, Z. H.; Sun, C. H.; Deng, L. G.; Zhang, S.; Xing, W.; Hu, X. N.; Ding, R. J.; He, L.

2016-09-01

A highly anisotropic etching process with low etch-induced damage is indispensable for advanced HgCdTe (MCT) infrared focal plane array (IRFPA) detectors. The inductively coupled plasma (ICP) enhanced reactive ion etching technique has been widely adopted in manufacturing HgCdTe IRFPA devices. An accurately patterned mask with sharp edges is decisive to accomplish pattern duplication. It has been reported by our group that the SiO2 mask functions well in etching HgCdTe with high selectivity. However, the wet process in defining the SiO2 mask is limited by ambiguous edges and nonuniform patterns. In this report, we patterned SiO2 with a mature ICP etching technique, prior to which a thin ZnS film was deposited by thermal evaporation. The SiO2 film etching can be terminated at the auto-stopping point of the ZnS layer thanks to the high selectivity of SiO2/ZnS in SF6 based etchant. Consequently, MCT etching was directly performed without any other treatment. This mask showed acceptable profile due to the maturity of the SiO2 etching process. The well-defined SiO2 pattern and the etched smooth surfaces were investigated with scanning electron microscopy and atomic force microscope. This new mask process could transfer the patterns exactly with very small etch-bias. A cavity with aspect-ratio (AR) of 1.2 and root mean square roughness of 1.77 nm was achieved first, slightly higher AR of 1.67 was also get with better mask profile. This masking process ensures good uniformity and surely benefits the delineation of shrinking pixels with its high resolution.

Masking Strategies for Image Manifolds.

PubMed

Dadkhahi, Hamid; Duarte, Marco F

2016-07-07

We consider the problem of selecting an optimal mask for an image manifold, i.e., choosing a subset of the pixels of the image that preserves the manifold's geometric structure present in the original data. Such masking implements a form of compressive sensing through emerging imaging sensor platforms for which the power expense grows with the number of pixels acquired. Our goal is for the manifold learned from masked images to resemble its full image counterpart as closely as possible. More precisely, we show that one can indeed accurately learn an image manifold without having to consider a large majority of the image pixels. In doing so, we consider two masking methods that preserve the local and global geometric structure of the manifold, respectively. In each case, the process of finding the optimal masking pattern can be cast as a binary integer program, which is computationally expensive but can be approximated by a fast greedy algorithm. Numerical experiments show that the relevant manifold structure is preserved through the datadependent masking process, even for modest mask sizes.

The automatic back-check mechanism of mask tooling database and automatic transmission of mask tooling data

NASA Astrophysics Data System (ADS)

Xu, Zhe; Peng, M. G.; Tu, Lin Hsin; Lee, Cedric; Lin, J. K.; Jan, Jian Feng; Yin, Alb; Wang, Pei

2006-10-01

Nowadays, most foundries have paid more and more attention in order to reduce the CD width. Although the lithography technologies have developed drastically, mask data accuracy is still a big challenge than before. Besides, mask (reticle) price also goes up drastically such that data accuracy needs more special treatments.We've developed a system called eFDMS to guarantee the mask data accuracy. EFDMS is developed to do the automatic back-check of mask tooling database and the data transmission of mask tooling. We integrate our own EFDMS systems to engage with the standard mask tooling system K2 so that the upriver and the downriver processes of the mask tooling main body K2 can perform smoothly and correctly with anticipation. The competition in IC marketplace is changing from high-tech process to lower-price gradually. How to control the reduction of the products' cost more plays a significant role in foundries. Before the violent competition's drawing nearer, we should prepare the cost task ahead of time.

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

NASA Astrophysics Data System (ADS)

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

2009-10-01

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

A mask quality control tool for the OSIRIS multi-object spectrograph

NASA Astrophysics Data System (ADS)

López-Ruiz, J. C.; Vaz Cedillo, Jacinto Javier; Ederoclite, Alessandro; Bongiovanni, Ángel; González Escalera, Víctor

2012-09-01

OSIRIS multi object spectrograph uses a set of user-customised-masks, which are manufactured on-demand. The manufacturing process consists of drilling the specified slits on the mask with the required accuracy. Ensuring that slits are on the right place when observing is of vital importance. We present a tool for checking the quality of the process of manufacturing the masks which is based on analyzing the instrument images obtained with the manufactured masks on place. The tool extracts the slit information from these images, relates specifications with the extracted slit information, and finally communicates to the operator if the manufactured mask fulfills the expectations of the mask designer. The proposed tool has been built using scripting languages and using standard libraries such as opencv, pyraf and scipy. The software architecture, advantages and limits of this tool in the lifecycle of a multiobject acquisition are presented.

Dynamic mask for producing uniform or graded-thickness thin films

DOEpatents

Folta, James A [Livermore, CA

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.

Antigen Masking During Fixation and Embedding, Dissected

PubMed Central

Scalia, Carla Rossana; Boi, Giovanna; Bolognesi, Maddalena Maria; Riva, Lorella; Manzoni, Marco; DeSmedt, Linde; Bosisio, Francesca Maria; Ronchi, Susanna; Leone, Biagio Eugenio; Cattoretti, Giorgio

2016-01-01

Antigen masking in routinely processed tissue is a poorly understood process caused by multiple factors. We sought to dissect the effect on antigenicity of each step of processing by using frozen sections as proxies of the whole tissue. An equivalent extent of antigen masking occurs across variable fixation times at room temperature. Most antigens benefit from longer fixation times (>24 hr) for optimal detection after antigen retrieval (AR; for example, Ki-67, bcl-2, ER). The transfer to a graded alcohol series results in an enhanced staining effect, reproduced by treating the sections with detergents, possibly because of a better access of the polymeric immunohistochemical detection system to tissue structures. A second round of masking occurs upon entering the clearing agent, mostly at the paraffin embedding step. This may depend on the non-freezable water removal. AR fully reverses the masking due both to the fixation time and the paraffin embedding. AR itself destroys some epitopes which do not survive routine processing. Processed frozen sections are a tool to investigate fixation and processing requirements for antigens in routine specimens. PMID:27798289

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).

Intact figure-ground segmentation in schizophrenia.

PubMed

Herzog, Michael H; Kopmann, Sabine; Brand, Andreas

2004-11-30

As revealed by backward masking studies, schizophrenic patients show strong impairments of early visual processing. However, the underlying temporal mechanisms are not yet well understood. To shed light on the exact timing of these deficits, we employed a paradigm in which two masks follow each other. We investigated 16 medicated schizophrenic patients and a matched group of 14 controls with a new backward masking technique, shine-through. In accordance with other masking studies, schizophrenic patients require a dramatically longer processing time to reach a predefined performance level compared with healthy subjects. However, patients are surprisingly sensitive to subtle differences in the timing of the two masks, revealing good temporal resolution. This good temporal resolution indicates intact and fast perceptual grouping and figure-ground segmentation in spite of high susceptibility to masking procedures in schizophrenia.

Task-Dependent Masked Priming Effects in Visual Word Recognition

PubMed Central

Kinoshita, Sachiko; Norris, Dennis

2012-01-01

A method used widely to study the first 250 ms of visual word recognition is masked priming: These studies have yielded a rich set of data concerning the processes involved in recognizing letters and words. In these studies, there is an implicit assumption that the early processes in word recognition tapped by masked priming are automatic, and masked priming effects should therefore be invariant across tasks. Contrary to this assumption, masked priming effects are modulated by the task goal: For example, only word targets show priming in the lexical decision task, but both words and non-words do in the same-different task; semantic priming effects are generally weak in the lexical decision task but are robust in the semantic categorization task. We explain how such task dependence arises within the Bayesian Reader account of masked priming (Norris and Kinoshita, 2008), and how the task dissociations can be used to understand the early processes in lexical access. PMID:22675316

Economic consequences of high throughput maskless lithography

NASA Astrophysics Data System (ADS)

Hartley, John G.; Govindaraju, Lakshmi

2005-11-01

Many people in the semiconductor industry bemoan the high costs of masks and view mask cost as one of the significant barriers to bringing new chip designs to market. All that is needed is a viable maskless technology and the problem will go away. Numerous sites around the world are working on maskless lithography but inevitably, the question asked is "Wouldn't a one wafer per hour maskless tool make a really good mask writer?" Of course, the answer is yes, the hesitation you hear in the answer isn't based on technology concerns, it's financial. The industry needs maskless lithography because mask costs are too high. Mask costs are too high because mask pattern generators (PG's) are slow and expensive. If mask PG's become much faster, mask costs go down, the maskless market goes away and the PG supplier is faced with an even smaller tool demand from the mask shops. Technical success becomes financial suicide - or does it? In this paper we will present the results of a model that examines some of the consequences of introducing high throughput maskless pattern generation. Specific features in the model include tool throughput for masks and wafers, market segmentation by node for masks and wafers and mask cost as an entry barrier to new chip designs. How does the availability of low cost masks and maskless tools affect the industries tool makeup and what is the ultimate potential market for high throughput maskless pattern generators?

Method for the fabrication of three-dimensional microstructures by deep X-ray lithography

DOEpatents

Sweatt, William C.; Christenson, Todd R.

2005-04-05

A method for the fabrication of three-dimensional microstructures by deep X-ray lithography (DXRL) comprises a masking process that uses a patterned mask with inclined mask holes and off-normal exposures with a DXRL beam aligned with the inclined mask holes. Microstructural features that are oriented in different directions can be obtained by using multiple off-normal exposures through additional mask holes having different orientations. Various methods can be used to block the non-aligned mask holes from the beam when using multiple exposures. A method for fabricating a precision 3D X-ray mask comprises forming an intermediate mask and a master mask on a common support membrane.

Cryogenic Etching of High Aspect Ratio 400 nm Pitch Silicon Gratings.

PubMed

Miao, Houxun; Chen, Lei; Mirzaeimoghri, Mona; Kasica, Richard; Wen, Han

2016-10-01

The cryogenic process and Bosch process are two widely used processes for reactive ion etching of high aspect ratio silicon structures. This paper focuses on the cryogenic deep etching of 400 nm pitch silicon gratings with various etching mask materials including polymer, Cr, SiO 2 and Cr-on-polymer. The undercut is found to be the key factor limiting the achievable aspect ratio for the direct hard masks of Cr and SiO 2 , while the etch selectivity responds to the limitation of the polymer mask. The Cr-on-polymer mask provides the same high selectivity as Cr and reduces the excessive undercut introduced by direct hard masks. By optimizing the etching parameters, we etched a 400 nm pitch grating to ≈ 10.6 μ m depth, corresponding to an aspect ratio of ≈ 53.

Optical inspection of NGL masks

NASA Astrophysics Data System (ADS)

Pettibone, Donald W.; Stokowski, Stanley E.

2004-12-01

For the last five years KLA-Tencor and our joint venture partners have pursued a research program studying the ability of optical inspection tools to meet the inspection needs of possible NGL lithographies. The NGL technologies that we have studied include SCALPEL, PREVAIL, EUV lithography, and Step and Flash Imprint Lithography. We will discuss the sensitivity of the inspection tools and mask design factors that affect tool sensitivity. Most of the work has been directed towards EUV mask inspection and how to optimize the mask to facilitate inspection. Our partners have succeeded in making high contrast EUV masks ranging in contrast from 70% to 98%. Die to die and die to database inspection of EUV masks have been achieved with a sensitivity that is comparable to what can be achieved with conventional photomasks, approximately 80nm defect sensitivity. We have inspected SCALPEL masks successfully. We have found a limitation of optical inspection when applied to PREVAIL stencil masks. We have run inspections on SFIL masks in die to die, reflected light, in an effort to provide feedback to improve the masks. We have used a UV inspection system to inspect both unpatterned EUV substrates (no coatings) and blanks (with EUV multilayer coatings). These inspection results have proven useful in driving down the substrate and blank defect levels.

Investigation of e-beam sensitive negative-tone chemically amplified resists for binary mask making

NASA Astrophysics Data System (ADS)

Irmscher, Mathias; Berger, Lothar; Beyer, Dirk; Butschke, Joerg; Dress, Peter; Hoffmann, Thomas; Hudek, Peter; Koepernik, Corinna; Tschinkl, Martin; Voehringer, Peter

2003-08-01

Negative-tone chemically amplified resists MES-EN1G (JSR), FEN-270 (Fujifilm ARCH), EN-024M (TOK) and NEB-22 (Sumitomo) were evaluated for binary mask making. The investigations were performed on an advanced tool set comprising a 50kV e-beam writer Leica SB350, a Steag Hamatech hot/cool plate module APB5000, a Steag Hamatech developer ASP5000, an UNAXIS MASK ETCHER III and a SEM LEO1560 with integrated CD measurement option. We investigated and compared the evaluated resists in terms of resolution, e-beam sensitivity, resist profile, post exposure bake sensitivity, CD-uniformity, line edge roughness, pattern fidelity and etch resistance. Furthermore, the influence of post coating delay and post exposure delay in vacuum and air was determined.

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

NASA Astrophysics Data System (ADS)

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

2009-04-01

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

Effects of hard mask etch on final topography of advanced phase shift masks

NASA Astrophysics Data System (ADS)

Hortenbach, Olga; Rolff, Haiko; Lajn, Alexander; Baessler, Martin

2017-07-01

Continuous shrinking of the semiconductor device dimensions demands steady improvements of the lithographic resolution on wafer level. These requirements challenge the photomask industry to further improve the mask quality in all relevant printing characteristics. In this paper topography of the Phase Shift Masks (PSM) was investigated. Effects of hard mask etch on phase shift uniformity and mask absorber profile were studied. Design of experiments method (DoE) was used for the process optimization, whereas gas composition, bias power of the hard mask main etch and bias power of the over-etch were varied. In addition, influence of the over-etch time was examined at the end of the experiment. Absorber depth uniformity, sidewall angle (SWA), reactive ion etch lag (RIE lag) and through pitch (TP) dependence were analyzed. Measurements were performed by means of Atomic-force microscopy (AFM) using critical dimension (CD) mode with a boot-shaped tip. Scanning electron microscope (SEM) cross-section images were prepared to verify the profile quality. Finally CD analysis was performed to confirm the optimal etch conditions. Significant dependence of the absorber SWA on hard mask (HM) etch conditions was observed revealing an improvement potential for the mask absorber profile. It was found that hard mask etch can leave a depth footprint in the absorber layer. Thus, the etch depth uniformity of hard mask etch is crucial for achieving a uniform phase shift over the active mask area. The optimized hard mask etch process results in significantly improved mask topography without deterioration of tight CD specifications.

The MSFC complementary metal oxide semiconductor (including multilevel interconnect metallization) process handbook

NASA Technical Reports Server (NTRS)

Bouldin, D. L.; Eastes, R. W.; Feltner, W. R.; Hollis, B. R.; Routh, D. E.

1979-01-01

The fabrication techniques for creation of complementary metal oxide semiconductor integrated circuits at George C. Marshall Space Flight Center are described. Examples of C-MOS integrated circuits manufactured at MSFC are presented with functional descriptions of each. Typical electrical characteristics of both p-channel metal oxide semiconductor and n-channel metal oxide semiconductor discrete devices under given conditions are provided. Procedures design, mask making, packaging, and testing are included.

Research on the Improved Image Dodging Algorithm Based on Mask Technique

NASA Astrophysics Data System (ADS)

Yao, F.; Hu, H.; Wan, Y.

2012-08-01

The remote sensing image dodging algorithm based on Mask technique is a good method for removing the uneven lightness within a single image. However, there are some problems with this algorithm, such as how to set an appropriate filter size, for which there is no good solution. In order to solve these problems, an improved algorithm is proposed. In this improved algorithm, the original image is divided into blocks, and then the image blocks with different definitions are smoothed using the low-pass filters with different cut-off frequencies to get the background image; for the image after subtraction, the regions with different lightness are processed using different linear transformation models. The improved algorithm can get a better dodging result than the original one, and can make the contrast of the whole image more consistent.

Literature and Creative Expression.

ERIC Educational Resources Information Center

Carlson, Ruth Kearney

Films, records, and literature and technique books helpful in encouraging creativity and composition writing are listed and described under the following headings: Books on forms of poetry (4 items); Creative dramatics and puppetry (9); Masks and mask making (9); Oriental forms of poetry--Haiku (9), Tanka (2), and other Oriental verse patterns…

Vejigante

ERIC Educational Resources Information Center

Nardulli, Anna

2013-01-01

In the Puerto Rican Carnivale, a traditional figure seen in many parades is the "vejigante," a clown-like character who wears a colorful mask. The author's kindergarteners were learning about Carnivale in Spanish class, so making vejigante masks of their own in art class was a great idea--and an opportunity to teach them papier-mache…

Application of multi-tone mask technology in photolithographic fabrication of color filter components in LCD

NASA Astrophysics Data System (ADS)

Takada, Yoshihiro; Fukui, Matoko; Sai, Tsunehiro

2008-11-01

Recent progresses in the photoresists and photolithography for LCD industry applications have been primarily driven by the following two factors: advancement in the material performances (high resolution, high contrast ratio, low dielectric constant) for higher display quality, and cost reduction in the fabrication process. Along with crucial demand for cost competitiveness by improving production efficiency, environmental consciousness has been a major priority at fabrication process design to minimize the amount of waste produced. Having said the above, integration of two or more fabrication processes into a single process by using multi-tone mask technology has been the interest of research, due to its obvious advantage of reducing fabrication processes and cost. For example, multi-tone mask technology application has been widely employed on the TFT side to reduce the different types of photomasks being used. Similar trend has been employed on the CF side as well, where application of multi-tone mask technology is being investigated to integrate fabrication of multiple CF micro-components into a single process. In this presentation, we demonstrate a new approach of fabricating photospacer and peripheral CF components (MVA protrusion, sub-photospacers) in a single integrated process through multi-tone mask technology.

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

NASA Astrophysics Data System (ADS)

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

2015-10-01

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

Writing next-generation display photomasks

NASA Astrophysics Data System (ADS)

Sandstrom, Tor; Wahlsten, Mikael; Park, Youngjin

2016-10-01

Recent years have seen a fast technical development within the display area. Displays get ever higher pixel density and the pixels get smaller. Current displays have over 800 PPI and market forces will eventually drive for densities of 2000 PPI or higher. The transistor backplanes also get more complex. OLED displays require 4-7 transistors per pixel instead of the typical 1-2 transistors used for LCDs, and they are significantly more sensitive to errors. New large-area maskwriters have been developed for masks used in high volume production of screens for state-of-theart smartphones. Redesigned laser optics with higher NA and lower aberrations improve resolution and CD uniformity and reduce mura effects. The number of beams has been increased to maintain the throughput despite the higher writing resolution. OLED displays are highly sensitive to placement errors and registration in the writers has been improved. To verify the registration of produced masks a separate metrology system has been developed. The metrology system is self-calibrated to high accuracy. The calibration is repeatable across machines and sites using Z-correction. The repeatability of the coordinate system makes it possible to standardize the coordinate system across an entire supply chain or indeed across the entire industry. In-house metrology is a commercial necessity for high-end mask shop, but also the users of the masks, the panel makers, would benefit from having in-house metrology. It would act as the reference for their mask suppliers, give better predictive and post mortem diagnostic power for the panel process, and the metrology could be used to characterize and improve the entire production loop from data to panel.

Process optimization for particle removal on blank chrome mask plates in preparation for resist application

NASA Astrophysics Data System (ADS)

Osborne, Stephen; Smith, Eryn; Woster, Eric; Pelayo, Anthony

2002-03-01

As integrated circuits require smaller lines to provide the memory and processing capability for tomorrow's marketplace, the photomask industry is adopting higher contrast resists to improve photomask lithography. Photomask yield for several high-contrast resist recipes may be improved by coating masks at the mask shop. When coating at a mask shop, an effective method is available that uses coat/bake cluster tools to ensure blanks are clean prior to coating. Many high-contrast resists are available, and some are more susceptible to time-dependent performance factors than conventional resists. One of these factors is the time between coating and writing. Although future methods may reduce the impact of this factor, one current trend is to reduce this time by coating plates at the mask shop just prior to writing. Establishing an effective process to clean blanks prior to coating is necessary for product quality control and is a new task that is critical for maskmakers who previously purchased mask plates but have decided to begin coating them within their facility. This paper provides a strategy and method to be used within coat/bake cluster tools to remove particle contamination from mask blanks. The process uses excimer-UV ionizing radiation and ozone to remove organic contaminants, and then uses a wet process combined with megasonic agitation, surfactant, and spin forces. Megasonic agitation with surfactant lifts up particles, while the convective outflow of water enhances centripetal shear without accumulating harmful charge.

A pattern-based method to automate mask inspection files

NASA Astrophysics Data System (ADS)

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

2017-03-01

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

The Effect Of Digital Unsharp Masking On The Detectability Of Interstitial Infiltrates And Pneumothoraces

NASA Astrophysics Data System (ADS)

MacMahon, Heber; Vyborny, Carl; Sabeti, Victoria; Metz, Charles; Doi, Kunio

1985-09-01

A potential advantage of digital radiographic systems is their ability to enhance images by various types of processing. Digital unsharp masking is one of the simplest and potentially most useful forms of enhancement. The efficacy of unsharp masking in clinical radiologic diagnosis has not been investigated systematically, however. The effect of digital unsharp masking on the detectability of two types of subtle abnormalities, pneumothorax and interstitial infiltrate, was studied in an observer performance test. An ROC analysis of this preliminary data suggests that unsharp masking may improve diagnostic accuracy for pneumothorax. Radiologists' performance in identifying interstitial infiltrates was degraded by the image processing, however, and false positive diagnoses tended to be more frequent.

Advanced refractory-metal and process technology for the fabrication of x-ray masks

NASA Astrophysics Data System (ADS)

Brooks, Cameron J.; Racette, Kenneth C.; Lercel, Michael J.; Powers, Lynn A.; Benoit, Douglas E.

1999-06-01

This paper provides an in-depth report of the advanced materials and process technology being developed for x-ray mask manufacturing at IBM. Masks using diamond membranes as replacement for silicon carbide are currently being fabricated. Alternate tantalum-based absorbers, such as tantalum boron, which offer improved etch resolution and critical dimension control, as well as higher x-ray absorption, are also being investigated. In addition to the absorber studies, the development of conductive chromium- based hard-mask films to replace the current silicon oxynitride layer is being explored. The progress of this advanced-materials work, which includes significant enhancements to x-ray mask image-placement performance, will be outlined.

OPC care-area feedforwarding to MPC

NASA Astrophysics Data System (ADS)

Dillon, Brian; Peng, Yi-Hsing; Hamaji, Masakazu; Tsunoda, Dai; Muramatsu, Tomoyuki; Ohara, Shuichiro; Zou, Yi; Arnoux, Vincent; Baron, Stanislas; Zhang, Xiaolong

2016-10-01

Demand for mask process correction (MPC) is growing for leading-edge process nodes. MPC was originally intended to correct CD linearity for narrow assist features difficult to resolve on a photomask without any correction, but it has been extended to main features as process nodes have been shrinking. As past papers have observed, MPC shows improvements in photomask fidelity. Using advanced shape and dose corrections could give more improvements, especially at line-ends and corners. However, there is a dilemma on using such advanced corrections on full mask level because it increases data volume and run time. In addition, write time on variable shaped beam (VSB) writers also increases as the number of shots increases. Optical proximity correction (OPC) care-area defines circuit design locations that require high mask fidelity under mask writing process variations such as energy fluctuation. It is useful for MPC to switch its correction strategy and permit the use of advanced mask correction techniques in those local care-areas where they provide maximum wafer benefits. The use of mask correction techniques tailored to localized post-OPC design can result in similar desired level of data volume, run time, and write time. ASML Brion and NCS have jointly developed a method to feedforward the care-area information from Tachyon LMC to NDE-MPC to provide real benefit for improving both mask writing and wafer printing quality. This paper explains the detail of OPC care-area feedforwarding to MPC between ASML Brion and NCS, and shows the results. In addition, improvements on mask and wafer simulations are also shown. The results indicate that the worst process variation (PV) bands are reduced up to 37% for a 10nm tech node metal case.

Vortex Mask: Making 80nm contacts with a twist!

NASA Astrophysics Data System (ADS)

Levenson, Marc D.; Dai, Grace; Ebihara, Takeaki

2002-12-01

An optical vortex has a phase that spirals like a corkscrew. Since any nonzero optical amplitude must have a well-defined phase, the axis of a vortex (where the phase is undefined) is always dark. Printed in negative resist, lowest order vortices would produce contact holes with 0.20.6 can be produced using a chromeless phase-edge mask composed of rectangles with phases of 0°, 90°, 180° and 270°. EMF and Kirchhoff-approximation simulations reveal that the image quality of the dark spots is excellent, and predict a process window with 15% exposure latitude and 400nm DOF for 80nm diameter spots on pitches >=250nm at σ=0.15. EMF simulations predict that the 0-270° phase step will not be excessively dark if the quartz wall is vertical. Chrome spots at the centers can control the diameters which otherwise are set by the parameters of the imaging system and exposure dose. Unwanted vortices can be erased from the image by exposing with a second, more conventional, trim mask. This method would be superior to the other ways of producing sub-wavelength vias, but successful implementation requires the development of appropriate negative-tone resist processes.

Real-Time Implementation of Nonlinear Processing Functions.

DTIC Science & Technology

1981-08-01

crystal devices and then to use them in a coherent optical data- processing apparatus using halftone masks custom designed at the University oi Southern...California. With the halftone mask technique, we have demonstrated logarithmic nonlinear transformation, allowing us to separate multiplicative images...improved.,_ This device allowed nonlinear functions to be implemented directly wit - out the need for specially made halftone masks. Besides

Determining the energetic and informational components of speech-on-speech masking

PubMed Central

Kidd, Gerald; Mason, Christine R.; Swaminathan, Jayaganesh; Roverud, Elin; Clayton, Kameron K.; Best, Virginia

2016-01-01

Identification of target speech was studied under masked conditions consisting of two or four independent speech maskers. In the reference conditions, the maskers were colocated with the target, the masker talkers were the same sex as the target, and the masker speech was intelligible. The comparison conditions, intended to provide release from masking, included different-sex target and masker talkers, time-reversal of the masker speech, and spatial separation of the maskers from the target. Significant release from masking was found for all comparison conditions. To determine whether these reductions in masking could be attributed to differences in energetic masking, ideal time-frequency segregation (ITFS) processing was applied so that the time-frequency units where the masker energy dominated the target energy were removed. The remaining target-dominated “glimpses” were reassembled as the stimulus. Speech reception thresholds measured using these resynthesized ITFS-processed stimuli were the same for the reference and comparison conditions supporting the conclusion that the amount of energetic masking across conditions was the same. These results indicated that the large release from masking found under all comparison conditions was due primarily to a reduction in informational masking. Furthermore, the large individual differences observed generally were correlated across the three masking release conditions. PMID:27475139

Spatial release from masking based on binaural processing for up to six maskers

PubMed Central

Yost, William A.

2017-01-01

Spatial Release from Masking (SRM) was measured for identification of a female target word spoken in the presence of male masker words. Target words from a single loudspeaker located at midline were presented when two, four, or six masker words were presented either from the same source as the target or from spatially separated masker sources. All masker words were presented from loudspeakers located symmetrically around the centered target source in the front azimuth hemifield. Three masking conditions were employed: speech-in-speech masking (involving both informational and energetic masking), speech-in-noise masking (involving energetic masking), and filtered speech-in-filtered speech masking (involving informational masking). Psychophysical results were summarized as three-point psychometric functions relating proportion of correct word identification to target-to-masker ratio (in decibels) for both the co-located and spatially separated target and masker sources cases. SRM was then calculated by comparing the slopes and intercepts of these functions. SRM decreased as the number of symmetrically placed masker sources increased from two to six. This decrease was independent of the type of masking, with almost no SRM measured for six masker sources. These results suggest that when SRM is dependent primarily on binaural processing, SRM is effectively limited to fewer than six sound sources. PMID:28372135

Reticles, write time, and the need for speed

NASA Astrophysics Data System (ADS)

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

2014-10-01

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

Mask replication using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

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

2011-11-01

The Jet and Flash Imprint Lithography (J-FILTM) process uses drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for memory markets including Flash memory and patterned media for hard disk drives. It is anticipated that the lifetime of a single template (for patterned media) or mask (for semiconductor) will be on the order of 104 - 105imprints. This suggests that tens of thousands of templates/masks will be required to satisfy the needs of a manufacturing environment. Electron-beam patterning is too slow to feasibly deliver these volumes, but instead can provide a high quality "master" mask which can be replicated many times with an imprint lithography tool. This strategy has the capability to produce the required supply of "working" templates/masks. In this paper, we review the development of the mask form factor, imprint replication tools and the semiconductor mask replication process. A PerfectaTM MR5000 mask replication tool has been developed specifically to pattern replica masks from an ebeam written master. Performance results, including image placement, critical dimension uniformity, and pattern transfer are covered in detail.

Understanding and reduction of defects on finished EUV masks

NASA Astrophysics Data System (ADS)

Liang, Ted; Sanchez, Peter; Zhang, Guojing; Shu, Emily; Nagpal, Rajesh; Stivers, Alan

2005-05-01

To reduce the risk of EUV lithography adaptation for the 32nm technology node in 2009, Intel has operated a EUV mask Pilot Line since early 2004. The Pilot Line integrates all the necessary process modules including common tool sets shared with current photomask production as well as EUV specific tools. This integrated endeavor ensures a comprehensive understanding of any issues, and development of solutions for the eventual fabrication of defect-free EUV masks. Two enabling modules for "defect-free" masks are pattern inspection and repair, which have been integrated into the Pilot Line. This is the first time we are able to look at real defects originated from multilayer blanks and patterning process on finished masks over entire mask area. In this paper, we describe our efforts in the qualification of DUV pattern inspection and electron beam mask repair tools for Pilot Line operation, including inspection tool sensitivity, defect classification and characterization, and defect repair. We will discuss the origins of each of the five classes of defects as seen by DUV pattern inspection tool on finished masks, and present solutions of eliminating and mitigating them.

Gestalt grouping and common onset masking.

PubMed

Kahan, Todd A; Mathis, Katherine M

2002-11-01

A four-dot mask that surrounds and is presented simultaneously with a briefly presented target will reduce a person's ability to identity that target if the mask persists beyond target offset and attention is divided (Enns & Di Lollo, 1997, 2000). This masking effect, referred to as common onset masking, reflects reentrant processing in the visual system and can best be explained with a theory of object substitution (Di Lollo, Enns, & Rensink, 2000). In the present experiments, we investigated whether Gestalt grouping variables would influence the strength of common onset masking. The results indicated that (1) masking was impervious to grouping by form, similarity of color, position, luminance polarity, and common region and (2) masking increased with the number of elements in the masking display.

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.

Investigation of phase distribution using Phame® in-die phase measurements

NASA Astrophysics Data System (ADS)

Buttgereit, Ute; Perlitz, Sascha

2009-03-01

As lithography mask processes move toward 45nm and 32nm node, mask complexity increases steadily, mask specifications tighten and process control becomes extremely important. Driven by this fact the requirements for metrology tools increase as well. Efforts in metrology have been focused on accurately measuring CD linearity and uniformity across the mask, and accurately measuring phase variation on Alternating/Attenuated PSM and transmission for Attenuated PSM. CD control on photo masks is usually done through the following processes: exposure dose/focus change, resist develop and dry etch. The key requirement is to maintain correct CD linearity and uniformity across the mask. For PSM specifically, the effect of CD uniformity for both Alternating PSM and Attenuated PSM and etch depth for Alternating PSM becomes also important. So far phase measurement has been limited to either measuring large-feature phase using interferometer-based metrology tools or measuring etch depth using AFM and converting etch depth into phase under the assumption that trench profile and optical properties of the layers remain constant. However recent investigations show that the trench profile and optical property of layers impact the phase. This effect is getting larger for smaller CD's. The currently used phase measurement methods run into limitations because they are not able to capture 3D mask effects, diffraction limitations or polarization effects. The new phase metrology system - Phame(R) developed by Carl Zeiss SMS overcomes those limitations and enables laterally resolved phase measurement in any kind of production feature on the mask. The resolution of the system goes down to 120nm half pitch at mask level. We will report on tool performance data with respect to static and dynamic phase repeatability focusing on Alternating PSM. Furthermore the phase metrology system was used to investigate mask process signatures on Alternating PSM in order to further improve the overall PSM process performance. Especially global loading effects caused by the pattern density and micro loading effects caused by the feature size itself have been evaluated using the capability of measuring phase in the small production features. The results of this study will be reported in this paper.

Is fear perception special? Evidence at the level of decision-making and subjective confidence.

PubMed

Koizumi, Ai; Mobbs, Dean; Lau, Hakwan

2016-11-01

Fearful faces are believed to be prioritized in visual perception. However, it is unclear whether the processing of low-level facial features alone can facilitate such prioritization or whether higher-level mechanisms also contribute. We examined potential biases for fearful face perception at the levels of perceptual decision-making and perceptual confidence. We controlled for lower-level visual processing capacity by titrating luminance contrasts of backward masks, and the emotional intensity of fearful, angry and happy faces. Under these conditions, participants showed liberal biases in perceiving a fearful face, in both detection and discrimination tasks. This effect was stronger among individuals with reduced density in dorsolateral prefrontal cortex, a region linked to perceptual decision-making. Moreover, participants reported higher confidence when they accurately perceived a fearful face, suggesting that fearful faces may have privileged access to consciousness. Together, the results suggest that mechanisms in the prefrontal cortex contribute to making fearful face perception special. © The Author (2016). Published by Oxford University Press.

Dual-sided coded-aperture imager

DOEpatents

Ziock, Klaus-Peter [Clinton, TN

2009-09-22

In a vehicle, a single detector plane simultaneously measures radiation coming through two coded-aperture masks, one on either side of the detector. To determine which side of the vehicle a source is, the two shadow masks are inverses of each other, i.e., one is a mask and the other is the anti-mask. All of the data that is collected is processed through two versions of an image reconstruction algorithm. One treats the data as if it were obtained through the mask, the other as though the data is obtained through the anti-mask.

Effects of Temporal Integration on the Shape of Visual Backward Masking Functions

ERIC Educational Resources Information Center

Francis, Gregory; Cho, Yang Seok

2008-01-01

Many studies of cognition and perception use a visual mask to explore the dynamics of information processing of a target. Especially important in these applications is the time between the target and mask stimuli. A plot of some measure of target visibility against stimulus onset asynchrony is called a masking function, which can sometimes be…

Progress in mask replication using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

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

2011-04-01

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

A Self-Aligned a-IGZO Thin-Film Transistor Using a New Two-Photo-Mask Process with a Continuous Etching Scheme.

PubMed

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der

2014-08-11

Minimizing the parasitic capacitance and the number of photo-masks can improve operational speed and reduce fabrication costs. Therefore, in this study, a new two-photo-mask process is proposed that exhibits a self-aligned structure without an etching-stop layer. Combining the backside-ultraviolet (BUV) exposure and backside-lift-off (BLO) schemes can not only prevent the damage when etching the source/drain (S/D) electrodes but also reduce the number of photo-masks required during fabrication and minimize the parasitic capacitance with the decreasing of gate overlap length at same time. Compared with traditional fabrication processes, the proposed process yields that thin-film transistors (TFTs) exhibit comparable field-effect mobility (9.5 cm²/V·s), threshold voltage (3.39 V), and subthreshold swing (0.3 V/decade). The delay time of an inverter fabricated using the proposed process was considerably decreased.

A Self-Aligned a-IGZO Thin-Film Transistor Using a New Two-Photo-Mask Process with a Continuous Etching Scheme

PubMed Central

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der

2014-01-01

Minimizing the parasitic capacitance and the number of photo-masks can improve operational speed and reduce fabrication costs. Therefore, in this study, a new two-photo-mask process is proposed that exhibits a self-aligned structure without an etching-stop layer. Combining the backside-ultraviolet (BUV) exposure and backside-lift-off (BLO) schemes can not only prevent the damage when etching the source/drain (S/D) electrodes but also reduce the number of photo-masks required during fabrication and minimize the parasitic capacitance with the decreasing of gate overlap length at same time. Compared with traditional fabrication processes, the proposed process yields that thin-film transistors (TFTs) exhibit comparable field-effect mobility (9.5 cm2/V·s), threshold voltage (3.39 V), and subthreshold swing (0.3 V/decade). The delay time of an inverter fabricated using the proposed process was considerably decreased. PMID:28788159

A diffusion model account of masked vs. unmasked priming: Are they qualitatively different?

PubMed Central

Gomez, Pablo; Perea, Manuel; Ratcliff, Roger

2017-01-01

In the past decades, hundreds of articles have explored the mechanisms underlying priming. Most researchers assume that masked and unmasked priming are qualitatively different. For masked priming, the effects are often assumed to reflect savings in the encoding of the target stimulus, whereas for unmasked priming, it has been suggested that the effects reflect the familiarity of the prime-target compound cue. In contrast, other researchers have claimed that masked and unmasked priming reflect essentially the same core processes. In this article, we use the diffusion model (Ratcliff, 1978) to account for the effects of masked and unmasked priming for identity and associatively related primes. The fits of the model lead us to the following conclusion: masked related primes give a head start to the processing of the target compared to unrelated primes, while unmasked priming affects primarily the quality of the lexical information. PMID:23647337

[Thermoplastic mask in radiotherapy: a source of anxiety for the patient?].

PubMed

Arino, C; Stadelmaier, N; Dupin, C; Kantor, G; Henriques de Figueiredo, B

2014-12-01

The thermoplastic mask often used to immobilize patients in radiotherapy can cause varying levels of stress and anxiety. This study aimed at evaluating the anxiety related to the use of radiotherapy masks and the coping strategies adopted by patients. Nineteen patients treated with radiotherapy mask for head and neck cancer, a brain tumour or a lymphoma, were met twice by a psychologist, either after the making of the mask and the first course of radiotherapy, or in the middle and at the end of treatment. Thirty-four semi-structured interviews were treated using a thematic content analysis and 13 patients answered to anxiety (STAI-YB) and coping (WCC) scales. The STAI-YB anxiety scores related to wearing the masks were low during the radiotherapy treatment period, and were confirmed by the remarks of patients recorded during the semi-structured interviews. Most patients had a positive perception of the mask, and considered it as a friend or protection. Twelve out of the 13 patients admitting to anxiety benefited from problem focused coping strategies. Thermoplastic mask-related anxiety is low and possibly lies in the positive representation patients have about the mask. The explanations provided by health professionals on the radiotherapy mask possibly have a very positive effect on this perception. Copyright © 2014 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Etch bias inversion during EUV mask ARC etch

NASA Astrophysics Data System (ADS)

Lajn, Alexander; Rolff, Haiko; Wistrom, Richard

2017-07-01

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

Results from the first fully automated PBS-mask process and pelliclization

NASA Astrophysics Data System (ADS)

Oelmann, Andreas B.; Unger, Gerd M.

1994-02-01

Automation is widely discussed in IC- and mask-manufacturing and partially realized everywhere. The idea for the automation goes back to 1978, when it turned out that the operators for the then newly installed PBS-process-line (the first in Europe) should be trained to behave like robots for particle reduction gaining lower defect densities on the masks. More than this goal has been achieved. It turned out recently, that the automation with its dedicated work routes and detailed documentation of every lot (individual mask or reticle) made it easy to obtain the CEEC certificate which includes ISO 9001.

Variations in backward masking with different masking stimuli: II. The effects of spatially quantised masks in the light of local contour interaction, interchannel inhibition, perceptual retouch, and substitution theories.

PubMed

Bachmann, Talis; Luiga, Iiris; Põder, Endel

2005-01-01

In part I we showed that with spatially non-overlapping targets and masks both local metacontrast-like interactions and attentional processes are involved in backward masking. In this second part we extend the strategy of varying the contents of masks to pattern masking where targets and masks overlap in space, in order to compare different masking theories. Images of human faces were backward-masked by three types of spatially quantised masks (the same faces as targets, faces different from targets, and Gaussian noise with power spectra typical for faces). Configural characteristics, rather than the spectral content of the mask, predicted the extent of masking at relatively long stimulus onset asynchronies (SOAs). This poses difficulties for the theory of transient-on-sustained inhibition as the principal mechanism of masking and also for local contour interaction being a decisive factor in pattern masking. The scale of quantisation had no effect on the masking capacity of noise masks and a strong effect on the capacity of different-face masks. Also, the decrease of configural masking with an increase in the coarseness of the quantisation of the mask highlights ambiguities inherent in the re-entrance-based substitution theory of masking. Different masking theories cannot solve the problems of masking separately. They should be combined in order to create a complex, yet comprehensible mode of interaction for the different mechanisms involved in visual backward masking.

Novel contact hole reticle design for enhanced lithography process window in IC manufacturing

NASA Astrophysics Data System (ADS)

Chang, Chung-Hsing

2005-01-01

For 90nm node generation, 65nm, and beyond, dark field mask types such as contact-hole, via, and trench patterns that all are very challenging to print with satisfactory process windows for day-to-day lithography manufacturing. Resolution enhancement technology (RET) masks together with ArF high numerical aperture (NA) scanners have been recognized as the inevitable choice of method for 65nm node manufacturing. Among RET mask types, the alternating phase shifting mask (AltPSM) is one of the well-known strong enhancement techniques. However AltPSM can have a very strong optical proximity effect that comes with the use of small on-axis illumination sigma setting. For very dense contact features, it may be possible for AltPSM to overcome the phase conflict by limiting the mask design rules. But it is not feasible to resolve the inherent phase conflict for the semi-dense, semi-isolated and isolated contact areas. Hence the adoption of this strong enhancement technique for dark filed mask types in today"s IC manufacturing has been very limited. In this paper, we present a novel yet a very powerful design method to achieve contact and via masks printing for 90nm, 65nm, and beyond. We name our new mask design as: Novel Improved Contact-hole pattern Exposure PSM (NICE PSM) with off-axis illumination, such as QUASAR. This RET masks design can enhance the process window of isolated, semi-isolated contact hole and via hole patterns. The main concepts of NICE PSM with QUASAR off-axis illumination are analogous to the Super-FLEX pupil filter technology.

Novel contact hole reticle design for enhanced lithography process window in IC manufacturing

NASA Astrophysics Data System (ADS)

Chang, Chung-Hsing

2004-10-01

For 90nm node generation, 65nm, and beyond, dark field mask types such as contact-hole, via, and trench patterns that all are very challenging to print with satisfactory process windows for day-to-day lithography manufacturing. Resolution enhancement technology (RET) masks together with ArF high numerical aperture (NA) scanners have been recognized as the inevitable choice of method for 65nm node manufacturing. Among RET mask types, the alternating phase shifting mask (AltPSM) is one of the well-known strong enhancement techniques. However, AltPSM can have a very strong optical proximity effect that comes with the use of small on-axis illumination sigma setting. For very dense contact features, it may be possible for AltPSM to overcome the phase conflict by limiting the mask design rules. But it is not feasible to resolve the inherent phase conflict for the semi-dense, semi-isolated and isolated contact areas. Hence the adoption of this strong enhancement technique for dark filed mask types in today"s IC manufacturing has been very limited. In this paper, we report a novel yet a very powerful design method to achieve contact and via masks printing for 90nm, 65nm, and beyond. We name our new mask design as: Novel Improved Contact-hole pattern Exposure PSM (NICE PSM) with off-axis illumination, such as QUASAR. This RET masks design can enhance the process window of isolated, semi-isolated contact hole and via hole patterns. The main concepts of NICE PSM with QUASAR off-axis illumination are analogous to the Super-FLEX pupil filter technology.

The extended functional neuroanatomy of emotional processing biases for masked faces in major depressive disorder.

PubMed

Victor, Teresa A; Furey, Maura L; Fromm, Stephen J; Bellgowan, Patrick S F; Öhman, Arne; Drevets, Wayne C

2012-01-01

Major depressive disorder (MDD) is associated with a mood-congruent processing bias in the amygdala toward face stimuli portraying sad expressions that is evident even when such stimuli are presented below the level of conscious awareness. The extended functional anatomical network that maintains this response bias has not been established, however. To identify neural network differences in the hemodynamic response to implicitly presented facial expressions between depressed and healthy control participants. Unmedicated-depressed participants with MDD (n=22) and healthy controls (HC; n=25) underwent functional MRI as they viewed face stimuli showing sad, happy or neutral face expressions, presented using a backward masking design. The blood-oxygen-level dependent (BOLD) signal was measured to identify regions where the hemodynamic response to the emotionally valenced stimuli differed between groups. The MDD subjects showed greater BOLD responses than the controls to masked-sad versus masked-happy faces in the hippocampus, amygdala and anterior inferotemporal cortex. While viewing both masked-sad and masked-happy faces relative to masked-neutral faces, the depressed subjects showed greater hemodynamic responses than the controls in a network that included the medial and orbital prefrontal cortices and anterior temporal cortex. Depressed and healthy participants showed distinct hemodynamic responses to masked-sad and masked-happy faces in neural circuits known to support the processing of emotionally valenced stimuli and to integrate the sensory and visceromotor aspects of emotional behavior. Altered function within these networks in MDD may establish and maintain illness-associated differences in the salience of sensory/social stimuli, such that attention is biased toward negative and away from positive stimuli.

Accelerating yield ramp through design and manufacturing collaboration

NASA Astrophysics Data System (ADS)

Sarma, Robin C.; Dai, Huixiong; Smayling, Michael C.; Duane, Michael P.

2004-12-01

Ramping an integrated circuit from first silicon bring-up to production yield levels is a challenge for all semiconductor products on the path to profitable market entry. Two approaches to accelerating yield ramp are presented. The first is the use of laser mask writers for fast throughput, high yield, and cost effective pattern transfer. The second is the use of electrical test to find a defect and identify the physical region to probe in failure analysis that is most likely to uncover the root cause. This provides feedback to the design team on modifications to make to the design to avoid the yield issue in a future tape-out revision. Additionally, the process parameter responsible for the root cause of the defect is forward annotated through the design, mask and wafer coordinate systems so it can be monitored in-line on subsequent lots of the manufacturing run. This results in an improved recipe for the manufacturing equipment to potentially prevent the recurrence of the defect and raise yield levels on the following material. The test diagnostics approach is enabled by the seamless traceability of a feature across the design, photomask and wafer, made possible by a common data model for design, mask pattern generation and wafer fabrication.

Revisiting adoption of high transmission PSM: pros, cons and path forward

NASA Astrophysics Data System (ADS)

Ma, Z. Mark; McDonald, Steve; Progler, Chris

2009-12-01

High transmission attenuated phase shift masks (Hi-T PSM) have been successfully applied in volume manufacturing for certain memory devices. Moreover, numerous studies have shown the potential benefits of Hi-T PSM for specific lithography applications. In this paper, the potential for extending Hi-T PSM to logic devices, is revisited with an emphasis on understanding layout, transmission, and manufacturing of Hi-T PSM versus traditional 6% embedded attenuated phase shift mask (EAPSM). Simulations on various layouts show Hi-T PSM has advantage over EAPSM in low duty cycle line patterns and high duty cycle space patterns. The overall process window can be enhanced when Hi- T PSM is combined with optimized optical proximity correction (OPC), sub-resolution assist features (SRAF), and source illumination. Therefore, Hi-T PSM may be a viable and lower cost alternative to other complex resolution enhancement technology (RET) approaches. Aerial image measurement system (AIMS) results on test masks, based on an inverse lithography technology (ILT) generated layout, confirm the simulation results. New advancement in high transmission blanks also make low topography Hi-T PSM a reality, which can minimize scattering effects in high NA lithography.

The contents of visual working memory reduce uncertainty during visual search.

PubMed

Cosman, Joshua D; Vecera, Shaun P

2011-05-01

Information held in visual working memory (VWM) influences the allocation of attention during visual search, with targets matching the contents of VWM receiving processing benefits over those that do not. Such an effect could arise from multiple mechanisms: First, it is possible that the contents of working memory enhance the perceptual representation of the target. Alternatively, it is possible that when a target is presented among distractor items, the contents of working memory operate postperceptually to reduce uncertainty about the location of the target. In both cases, a match between the contents of VWM and the target should lead to facilitated processing. However, each effect makes distinct predictions regarding set-size manipulations; whereas perceptual enhancement accounts predict processing benefits regardless of set size, uncertainty reduction accounts predict benefits only with set sizes larger than 1, when there is uncertainty regarding the target location. In the present study, in which briefly presented, masked targets were presented in isolation, there was a negligible effect of the information held in VWM on target discrimination. However, in displays containing multiple masked items, information held in VWM strongly affected target discrimination. These results argue that working memory representations act at a postperceptual level to reduce uncertainty during visual search.

Lithographic qualification of high-transmission mask blank for 10nm node and beyond

NASA Astrophysics Data System (ADS)

Xu, Yongan; Faure, Tom; Viswanathan, Ramya; Lobb, Granger; Wistrom, Richard; Burns, Sean; Hu, Lin; Graur, Ioana; Bleiman, Ben; Fischer, Dan; Mignot, Yann; Sakamoto, Yoshifumi; Toda, Yusuke; Bolton, John; Bailey, Todd; Felix, Nelson; Arnold, John; Colburn, Matthew

2016-04-01

In this paper, we discuss the lithographic qualification of high transmission (High T) mask for Via and contact hole applications in 10nm node and beyond. First, the simulated MEEF and depth of focus (DoF) data are compared between the 6% and High T attnPSM masks with the transmission of High T mask blank varying from 12% to 20%. The 12% High T blank shows significantly better MEEF and larger DoF than those of 6% attnPSM mask blank, which are consistent with our wafer data. However, the simulations show no obvious advantage in MEEF and DoF when the blank transmittance is larger than 12%. From our wafer data, it has been seen that the common process window from High T mask is 40nm bigger than that from the 6% attnPSM mask. In the elongated bar structure with smaller aspect ratio, 1.26, the 12% High T mask shows significantly less develop CD pull back in the major direction. Compared to the High T mask, the optimized new illumination condition for 6% attnPSM shows limited improvement in MEEF and the DoF through pitch. In addition, by using the High T mask blank, we have also investigated the SRAF printing, side lobe printing and the resist profile through cross sections, and no patterning risk has been found for manufacturing. As part of this work new 12% High T mask blank materials and processes were developed, and a brief overview of key mask technology development results have been shared. Overall, it is concluded that the High T mask, 12% transmission, provides the most robust and extendable lithographic solution for 10nm node and beyond.

An alternative method of fabricating sub-micron resolution masks using excimer laser ablation

NASA Astrophysics Data System (ADS)

Hayden, C. J.; Eijkel, J. C. T.; Dalton, C.

2004-06-01

In the work presented here, an excimer laser micromachining system has been used successfully to fabricate high-resolution projection and contact masks. The contact masks were subsequently used to produce chrome-gold circular ac electro-osmotic pump (cACEOP) microelectrode arrays on glass substrates, using a conventional contact photolithography process. The contact masks were produced rapidly (~15 min each) and were found to be accurate to sub-micron resolution, demonstrating an alternative route for mask fabrication. Laser machined masks were also used in a laser-projection system, demonstrating that such fabrication techniques are also suited to projection lithography. The work addresses a need for quick reproduction of high-resolution contact masks, given their rapid degradation when compared to non-contact masks.

Masking of Figure-Ground Texture and Single Targets by Surround Inhibition: A Computational Spiking Model

PubMed Central

Supèr, Hans; Romeo, August

2012-01-01

A visual stimulus can be made invisible, i.e. masked, by the presentation of a second stimulus. In the sensory cortex, neural responses to a masked stimulus are suppressed, yet how this suppression comes about is still debated. Inhibitory models explain masking by asserting that the mask exerts an inhibitory influence on the responses of a neuron evoked by the target. However, other models argue that the masking interferes with recurrent or reentrant processing. Using computer modeling, we show that surround inhibition evoked by ON and OFF responses to the mask suppresses the responses to a briefly presented stimulus in forward and backward masking paradigms. Our model results resemble several previously described psychophysical and neurophysiological findings in perceptual masking experiments and are in line with earlier theoretical descriptions of masking. We suggest that precise spatiotemporal influence of surround inhibition is relevant for visual detection. PMID:22393370

65-nm full-chip implementation using double dipole lithography

NASA Astrophysics Data System (ADS)

Hsu, Stephen D.; Chen, J. Fung; Cororan, Noel; Knose, William T.; Van Den Broeke, Douglas J.; Laidig, Thomas L.; Wampler, Kurt E.; Shi, Xuelong; Hsu, Michael; Eurlings, Mark; Finders, Jo; Chiou, Tsann-Bim; Socha, Robert J.; Conley, Will; Hsieh, Yen W.; Tuan, Steve; Hsieh, Frank

2003-06-01

Double Dipole Lithography (DDL) has been demonstrated to be capable of patterning complex 2D patterns. Due to inherently high aerial imaging contrast, especially for dense features, we have found that it has a very good potential to meet manufacturing requirements for the 65nm node using ArF binary chrome masks. For patterning in the k1<0.35 regime without resorting to hard phase-shift masks (PSMs), DDL is one unique Resolution Enhancement Technique (RET) which can achieve an acceptable process window. To utilize DDL for printing actual IC devices, the original design data must be decomposed into "vertical (V)" and "horizontal (H)" masks for the respective X- and Y-dipole exposures. An improved two-pass, model-based, DDL mask data processing methodology has been established. It is capable of simultaneously converting complex logic and memory mask patterns into DDL compatible mask layout. To maximize the overlapped process window area, we have previously shown that the pattern-shielding algorithm must be intelligently applied together with both Scattering Bars (SBs) and model-based OPC (MOPC). Due to double exposures, stray light must be well-controlled to ensure uniform printing across the entire chip. One solution to minimize stray light is to apply large patches of solid chrome in open areas to reduce the background transmission during exposure. Unfortunately, this is not feasible for a typical clear-field poly gate masks to be patterned by a positive resist process. In this work, we report a production-worthy DDL mask pattern decomposition scheme for full-chip application. A new generation of DDL technology reticle set has been developed to verify the printing performance. Shielding is a critical part of the DDL. An innovative shielding scheme has been developed to protect the critical features and minimize the impact of stray light during double exposure.

Orientation tuning of contrast masking caused by motion streaks.

PubMed

Apthorp, Deborah; Cass, John; Alais, David

2010-08-01

We investigated whether the oriented trails of blur left by fast-moving dots (i.e., "motion streaks") effectively mask grating targets. Using a classic overlay masking paradigm, we varied mask contrast and target orientation to reveal underlying tuning. Fast-moving Gaussian blob arrays elevated thresholds for detection of static gratings, both monoptically and dichoptically. Monoptic masking at high mask (i.e., streak) contrasts is tuned for orientation and exhibits a similar bandwidth to masking functions obtained with grating stimuli (∼30 degrees). Dichoptic masking fails to show reliable orientation-tuned masking, but dichoptic masks at very low contrast produce a narrowly tuned facilitation (∼17 degrees). For iso-oriented streak masks and grating targets, we also explored masking as a function of mask contrast. Interestingly, dichoptic masking shows a classic "dipper"-like TVC function, whereas monoptic masking shows no dip and a steeper "handle". There is a very strong unoriented component to the masking, which we attribute to transiently biased temporal frequency masking. Fourier analysis of "motion streak" images shows interesting differences between dichoptic and monoptic functions and the information in the stimulus. Our data add weight to the growing body of evidence that the oriented blur of motion streaks contributes to the processing of fast motion signals.

Print-to-pattern dry film photoresist lithography

NASA Astrophysics Data System (ADS)

Garland, Shaun P.; Murphy, Terrence M., Jr.; Pan, Tingrui

2014-05-01

Here we present facile microfabrication processes, referred to as print-to-pattern dry film photoresist (DFP) lithography, that utilize the combined advantages of wax printing and DFP to produce micropatterned substrates with high resolution over a large surface area in a non-cleanroom setting. The print-to-pattern methods can be performed in an out-of-cleanroom environment making microfabrication much more accessible to minimally equipped laboratories. Two different approaches employing either wax photomasks or wax etchmasks from a solid ink desktop printer have been demonstrated that allow the DFP to be processed in a negative tone or positive tone fashion, respectively, with resolutions of 100 µm. The effect of wax melting on resolution and as a bonding material was also characterized. In addition, solid ink printers have the capacity to pattern large areas with high resolution, which was demonstrated by stacking DFP layers in a 50 mm × 50 mm woven pattern with 1 mm features. By using an office printer to generate the masking patterns, the mask designs can be easily altered in a graphic user interface to enable rapid prototyping.

Emitter formation in dendritic web silicon solar cells

NASA Technical Reports Server (NTRS)

Meier, D. L.; Rohatgi, A.; Campbell, R. B.; Alexander, P.; Fonash, S. J.; Singh, R.

1984-01-01

The use of liquid dopants and liquid masks for p-n junction formation in dendritic web solar cells was investigated and found to be equivalent to the use of gaseous dopants and CVD SiO2 masks previously used. This results in a projected cost reduction of 0.02 1980$/Watt for a 25 MW/year production line, and makes possible junction formation processes having a higher throughput than more conventional processes. The effect of a low-energy (0.4 keV) hydrogen ion implant on dendritic web solar cells was also investigated. Such an implant was observed to improve Voc and Jsc substantially. Measurements of internal quantum efficiency suggest that it is the base of the cell, rather than the emitter, which benefits from the hydrogen implant. The diffusion length for electrons in the p-type base increased from 53 microns to 150 microns in one case, with dendritic web cell efficiency being boosted to 15.2 percent. The mechanism by which low-energy hydrogen ions can penetrate deeply into the silicon to effect the observed improvement is not known at this time.

Germanium Lift-Off Masks for Thin Metal Film Patterning

NASA Technical Reports Server (NTRS)

Brown, Ari

2012-01-01

A technique has been developed for patterning thin metallic films that are, in turn, used to fabricate microelectronics circuitry and thin-film sensors. The technique uses germanium thin films as lift-off masks. This requires development of a technique to strip or undercut the germanium chemically without affecting the deposited metal. Unlike in the case of conventional polymeric lift-off masks, the substrate can be exposed to very high temperatures during processing (sputter deposition). The reason why polymeric liftoff masks cannot be exposed to very high temperatures (greater than 100 C) is because (a) they can become cross linked, making lift-off very difficult if not impossible, and (b) they can outgas nitrogen and oxygen, which then can react with the metal being deposited. Consequently, this innovation is expected to find use in the fabrication of transition edge sensors and microwave kinetic inductance detectors, which use thin superconducting films deposited at high temperature as their sensing elements. Transition edge sensors, microwave kinetic inductance detectors, and their circuitry are comprised of superconducting thin films, for example Nb and TiN. Reactive ion etching can be used to pattern these films; however, reactive ion etching also damages the underlying substrate, which is unwanted in many instances. Polymeric lift-off techniques permit thin-film patterning without any substrate damage, but they are difficult to remove and the polymer can outgas during thin-film deposition. The outgassed material can then react with the film with the consequence of altered and non-reproducible materials properties, which, in turn, is deleterious for sensors and their circuitry. The purpose of this innovation was to fabricate a germanium lift-off mask to be used for patterning thin metal films.

Applications of CPL mask technology for sub-65nm gate imaging

NASA Astrophysics Data System (ADS)

Litt, Lloyd C.; Conley, Will; Wu, Wei; Peters, Richie; Parker, Colita; Cobb, Jonathan; Kasprowicz, Bryan S.; van den Broeke, Doug; Park, J. C.; Karur-Shanmugam, Ramkumar

2005-05-01

The requirements for critical dimension control on gate layer for high performance products are increasingly demanding. Phase shift techniques provide aerial image enhancement, which can translate into improved process window performance and greater critical dimension (CD) control if properly applied. Unfortunately, the application of hard shifter technology to production requires significant effort in layout and optical proximity correction (OPC) application. Chromeless Phase Lithography (CPL) has several advantages over complementary phase mask (c:PSM) such as use of a single mask, and lack of phase placement 'coloring' conflicts and phase imbalance issues. CPL does have implementation issues that must be resolved before it can be used in full-scale production. CPL mask designs can be approached by separating features into three zones based on several parameters, including size relative to the lithographic resolution of the stepper lens, wavelength, and illumination conditions defined. Features are placed into buckets for different treatment zones. Zone 1 features are constructed with 100% transmission phase shifted structures and Zone 3 features are chrome (binary) structures. Features that fall into Zone 2, which are too wide to be defined using the 100% transmission of pure CPL (i.e. have negative mask error factor, MEEF) are the most troublesome and can be approached in several ways. The authors have investigated the application of zebra structures of various sizes to product type layouts. Previous work to investigate CPL using test structures set the groundwork for the more difficult task of applying CPL rules to actual random logic design layouts, which include many zone transitions. Mask making limitations have been identified that play a role in the zebra sizing that can be applied to Zone 2 features. The elimination of Zone 2 regions was also investigated in an effort to simplify the application of CPL and improve manufacturability of reticle through data enhancements.

Removal of bone in CT angiography by multiscale matched mask bone elimination.

PubMed

Gratama van Andel, H A F; Venema, H W; Streekstra, G J; van Straten, M; Majoie, C B L M; den Heeten, G J; Grimbergen, C A

2007-10-01

For clear visualization of vessels in CT angiography (CTA) images of the head and neck using maximum intensity projection (MIP) or volume rendering (VR) bone has to be removed. In the past we presented a fully automatic method to mask the bone [matched mask bone elimination (MMBE)] for this purpose. A drawback is that vessels adjacent to bone may be partly masked as well. We propose a modification, multiscale MMBE, which reduces this problem by using images at two scales: a higher resolution than usual for image processing and a lower resolution to which the processed images are transformed for use in the diagnostic process. A higher in-plane resolution is obtained by the use of a sharper reconstruction kernel. The out-of-plane resolution is improved by deconvolution or by scanning with narrower collimation. The quality of the mask that is used to remove bone is improved by using images at both scales. After masking, the desired resolution for the normal clinical use of the images is obtained by blurring with Gaussian kernels of appropriate widths. Both methods (multiscale and original) were compared in a phantom study and with clinical CTA data sets. With the multiscale approach the width of the strip of soft tissue adjacent to the bone that is masked can be reduced from 1.0 to 0.2 mm without reducing the quality of the bone removal. The clinical examples show that vessels adjacent to bone are less affected and therefore better visible. Images processed with multiscale MMBE have a slightly higher noise level or slightly reduced resolution compared with images processed by the original method and the reconstruction and processing time is also somewhat increased. Nevertheless, multiscale MMBE offers a way to remove bone automatically from CT angiography images without affecting the integrity of the blood vessels. The overall image quality of MIP or VR images is substantially improved relative to images processed with the original MMBE method.

Low cost solar array project cell and module formation research area: Process research of non-CZ silicon material

NASA Technical Reports Server (NTRS)

1981-01-01

Liquid diffusion masks and liquid applied dopants to replace the CVD Silox masking and gaseous diffusion operations specified for forming junctions in the Westinghouse baseline process sequence for producing solar cells from dendritic web silicon were investigated. The baseline diffusion masking and drive processes were compared with those involving direct liquid applications to the dendritic web silicon strips. Attempts were made to control the number of variables by subjecting dendritic web strips cut from a single web crystal to both types of operations. Data generated reinforced earlier conclusions that efficiency levels at least as high as those achieved with the baseline back junction formation process can be achieved using liquid diffusion masks and liquid dopants. The deliveries of dendritic web sheet material and solar cells specified by the current contract were made as scheduled.

Dry etching technologies for the advanced binary film

NASA Astrophysics Data System (ADS)

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

2011-11-01

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

CMOS array design automation techniques

NASA Technical Reports Server (NTRS)

Lombardi, T.; Feller, A.

1976-01-01

The design considerations and the circuit development for a 4096-bit CMOS SOS ROM chip, the ATL078 are described. Organization of the ATL078 is 512 words by 8 bits. The ROM was designed to be programmable either at the metal mask level or by a directed laser beam after processing. The development of a 4K CMOS SOS ROM fills a void left by available ROM chip types, and makes the design of a totally major high speed system more realizable.

Effects of temporal integration on the shape of visual backward masking functions.

PubMed

Francis, Gregory; Cho, Yang Seok

2008-10-01

Many studies of cognition and perception use a visual mask to explore the dynamics of information processing of a target. Especially important in these applications is the time between the target and mask stimuli. A plot of some measure of target visibility against stimulus onset asynchrony is called a masking function, which can sometimes be monotonic increasing but other times is U-shaped. Theories of backward masking have long hypothesized that temporal integration of the target and mask influences properties of masking but have not connected the influence of integration with the shape of the masking function. With two experiments that vary the spatial properties of the target and mask, the authors provide evidence that temporal integration of the stimuli plays a critical role in determining the shape of the masking function. The resulting data both challenge current theories of backward masking and indicate what changes to the theories are needed to account for the new data. The authors further discuss the implication of the findings for uses of backward masking to explore other aspects of cognition.

Attentional Sensitization of Unconscious Cognition: Task Sets Modulate Subsequent Masked Semantic Priming

ERIC Educational Resources Information Center

Kiefer, Markus; Martens, Ulla

2010-01-01

According to classical theories, automatic processes are autonomous and independent of higher level cognitive influence. In contrast, the authors propose that automatic processing depends on attentional sensitization of task-congruent processing pathways. In 3 experiments, the authors tested this hypothesis with a modified masked semantic priming…

Improvement of sub-20nm pattern quality with dose modulation technique for NIL template production

NASA Astrophysics Data System (ADS)

Yagawa, Keisuke; Ugajin, Kunihiro; Suenaga, Machiko; Kanamitsu, Shingo; Motokawa, Takeharu; Hagihara, Kazuki; Arisawa, Yukiyasu; Kobayashi, Sachiko; Saito, Masato; Ito, Masamitsu

2016-04-01

Nanoimprint lithography (NIL) technology is in the spotlight as a next-generation semiconductor manufacturing technique for integrated circuits at 22 nm and beyond. NIL is the unmagnified lithography technique using template which is replicated from master templates. On the other hand, master templates are currently fabricated by electron-beam (EB) lithography[1]. In near future, finer patterns less than 15nm will be required on master template and EB data volume increases exponentially. So, we confront with a difficult challenge. A higher resolution EB mask writer and a high performance fabrication process will be required. In our previous study, we investigated a potential of photomask fabrication process for finer patterning and achieved 15.5nm line and space (L/S) pattern on template by using VSB (Variable Shaped Beam) type EB mask writer and chemically amplified resist. In contrast, we found that a contrast loss by backscattering decreases the performance of finer patterning. For semiconductor devices manufacturing, we must fabricate complicated patterns which includes high and low density simultaneously except for consecutive L/S pattern. Then it's quite important to develop a technique to make various size or coverage patterns all at once. In this study, a small feature pattern was experimentally formed on master template with dose modulation technique. This technique makes it possible to apply the appropriate exposure dose for each pattern size. As a result, we succeed to improve the performance of finer patterning in bright field area. These results show that the performance of current EB lithography process have a potential to fabricate NIL template.

Studies on the formation, temporal evolution and forensic applications of camera "fingerprints".

PubMed

Kuppuswamy, R

2006-06-02

A series of experiments was conducted by exposing negative film in brand new cameras of different make and model. The exposures were repeated at regular time intervals spread over a period of 2 years. The processed film negatives were studied under a stereomicroscope (10-40x) in transmitted illumination for the presence of the characterizing features on their four frame-edges. These features were then related to those present on the masking frame of the cameras by examining the latter in reflected light stereomicroscopy (10-40x). The purpose of the study was to determine the origin and permanence of the frame-edge-marks, and also the processes by which the marks may probably alter with time. The investigations have arrived at the following conclusions: (i) the edge-marks have originated principally from the imperfections received on the film mask from the manufacturing and also occasionally from the accumulated dirt, dust and fiber on the film mask over an extended time period. (ii) The edge profiles of the cameras have remained fixed over a considerable period of time so as to be of a valuable identification medium. (iii) The marks are found to be varying in nature even with those cameras manufactured at similar time. (iv) The influence of f/number and object distance has great effect in the recording of the frame-edge marks during exposure of the film. The above findings would serve as a useful addition to the technique of camera edge-mark comparisons.

Pixel-based OPC optimization based on conjugate gradients.

PubMed

Ma, Xu; Arce, Gonzalo R

2011-01-31

Optical proximity correction (OPC) methods are resolution enhancement techniques (RET) used extensively in the semiconductor industry to improve the resolution and pattern fidelity of optical lithography. In pixel-based OPC (PBOPC), the mask is divided into small pixels, each of which is modified during the optimization process. Two critical issues in PBOPC are the required computational complexity of the optimization process, and the manufacturability of the optimized mask. Most current OPC optimization methods apply the steepest descent (SD) algorithm to improve image fidelity augmented by regularization penalties to reduce the complexity of the mask. Although simple to implement, the SD algorithm converges slowly. The existing regularization penalties, however, fall short in meeting the mask rule check (MRC) requirements often used in semiconductor manufacturing. This paper focuses on developing OPC optimization algorithms based on the conjugate gradient (CG) method which exhibits much faster convergence than the SD algorithm. The imaging formation process is represented by the Fourier series expansion model which approximates the partially coherent system as a sum of coherent systems. In order to obtain more desirable manufacturability properties of the mask pattern, a MRC penalty is proposed to enlarge the linear size of the sub-resolution assistant features (SRAFs), as well as the distances between the SRAFs and the main body of the mask. Finally, a projection method is developed to further reduce the complexity of the optimized mask pattern.

ScAlN etch mask for highly selective silicon etching

DOE PAGES

Henry, Michael David; Young, Travis R.; Griffin, Ben

2017-09-08

Here, this work reports the utilization of a recently developed film, ScAlN, as a silicon etch mask offering significant improvements in high etch selectivity to silicon. Utilization of ScAlN as a fluorine chemistry based deep reactive ion etch mask demonstrated etch selectivity at 23 550:1, four times better than AlN, 11 times better than Al 2O 3, and 148 times better than silicon dioxide with significantly less resputtering at high bias voltage than either Al 2O 3 or AlN. Ellipsometry film thickness measurements show less than 0.3 nm/min mask erosion rates for ScAlN. Micromasking of resputtered Al for Al 2Omore » 3, AlN, and ScAlN etch masks is also reported here, utilizing cross-sectional scanning electron microscope and confocal microscope roughness measurements. With lower etch bias, the reduced etch rate can be optimized to achieve a trench bottom surface roughness that is comparable to SiO 2 etch masks. Etch mask selectivity enabled by ScAlN is likely to make significant improvements in microelectromechanical systems, wafer level packaging, and plasma dicing of silicon.« less

Etching Selectivity of Cr, Fe and Ni Masks on Si & SiO2 Wafers

NASA Astrophysics Data System (ADS)

Garcia, Jorge; Lowndes, Douglas H.

2000-10-01

During this Summer 2000 I joined the Semiconductors and Thin Films group led by Dr. Douglas H. Lowndes at Oak Ridge National Laboratory’s Solid State Division. Our objective was to evaluate the selectivity that Trifluoromethane (CHF3), and Sulfur Hexafluoride (SF6) plasmas have for Si, SiO2 wafers and the Ni, Cr, and Fe masks; being this etching selectivity the ratio of the etching rates of the plasmas for each of the materials. We made use of Silicon and Silicon Dioxide-coated wafers that have Fe, Cr or Ni masks. In the semiconductor field, metal layers are often used as masks to protect layers underneath during processing steps; when these wafers are taken to the dry etching process, both the wafer and the mask layers’ thickness are reduced.

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 could also achieve under 5nm performance. We assume mask registration excluding random error is mostly induced by charge accumulation during mask writing, which may be calculated from surrounding exposed pattern density. Multi-loading test mask registration result shows that with x direction writing sequence, mask registration behavior in x direction is mainly related to sequence direction, but mask registration in y direction would be highly impacted by pattern density distribution map. It proves part of mask registration error is due to charge issue from nearby environment. If exposure sequence is chip by chip for normal multi chip layout case, mask registration of both x and y direction would be impacted analogously, which has also been proved by real data. Therefore, we try to set up a simple model to predict the mask registration error based on mask exposure map, and correct it with the given POSCOR (position correction) file for advanced mask writing if needed.

Automatic pattern localization across layout database and photolithography mask

NASA Astrophysics Data System (ADS)

Morey, Philippe; Brault, Frederic; Beisser, Eric; Ache, Oliver; Röth, Klaus-Dieter

2016-03-01

Advanced process photolithography masks require more and more controls for registration versus design and critical dimension uniformity (CDU). The distribution of the measurement points should be distributed all over the whole mask and may be denser in areas critical to wafer overlay requirements. This means that some, if not many, of theses controls should be made inside the customer die and may use non-dedicated patterns. It is then mandatory to access the original layout database to select patterns for the metrology process. Finding hundreds of relevant patterns in a database containing billions of polygons may be possible, but in addition, it is mandatory to create the complete metrology job fast and reliable. Combining, on one hand, a software expertise in mask databases processing and, on the other hand, advanced skills in control and registration equipment, we have developed a Mask Dataprep Station able to select an appropriate number of measurement targets and their positions in a huge database and automatically create measurement jobs on the corresponding area on the mask for the registration metrology system. In addition, the required design clips are generated from the database in order to perform the rendering procedure on the metrology system. This new methodology has been validated on real production line for the most advanced process. This paper presents the main challenges that we have faced, as well as some results on the global performances.

How smart is your BEOL? productivity improvement through intelligent automation

NASA Astrophysics Data System (ADS)

Schulz, Kristian; Egodage, Kokila; Tabbone, Gilles; Garetto, Anthony

2017-07-01

The back end of line (BEOL) workflow in the mask shop still has crucial issues throughout all standard steps which are inspection, disposition, photomask repair and verification of repair success. All involved tools are typically run by highly trained operators or engineers who setup jobs and recipes, execute tasks, analyze data and make decisions based on the results. No matter how experienced operators are and how good the systems perform, there is one aspect that always limits the productivity and effectiveness of the operation: the human aspect. Human errors can range from seemingly rather harmless slip-ups to mistakes with serious and direct economic impact including mask rejects, customer returns and line stops in the wafer fab. Even with the introduction of quality control mechanisms that help to reduce these critical but unavoidable faults, they can never be completely eliminated. Therefore the mask shop BEOL cannot run in the most efficient manner as unnecessary time and money are spent on processes that still remain labor intensive. The best way to address this issue is to automate critical segments of the workflow that are prone to human errors. In fact, manufacturing errors can occur for each BEOL step where operators intervene. These processes comprise of image evaluation, setting up tool recipes, data handling and all other tedious but required steps. With the help of smart solutions, operators can work more efficiently and dedicate their time to less mundane tasks. Smart solutions connect tools, taking over the data handling and analysis typically performed by operators and engineers. These solutions not only eliminate the human error factor in the manufacturing process but can provide benefits in terms of shorter cycle times, reduced bottlenecks and prediction of an optimized workflow. In addition such software solutions consist of building blocks that seamlessly integrate applications and allow the customers to use tailored solutions. To accommodate for the variability and complexity in mask shops today, individual workflows can be supported according to the needs of any particular manufacturing line with respect to necessary measurement and production steps. At the same time the efficiency of assets is increased by avoiding unneeded cycle time and waste of resources due to the presence of process steps that are very crucial for a given technology. In this paper we present details of which areas of the BEOL can benefit most from intelligent automation, what solutions exist and the quantification of benefits to a mask shop with full automation by the use of a back end of line model.

Joint optimization of source, mask, and pupil in optical lithography

NASA Astrophysics Data System (ADS)

Li, Jia; Lam, Edmund Y.

2014-03-01

Mask topography effects need to be taken into consideration for more advanced resolution enhancement techniques in optical lithography. However, rigorous 3D mask model achieves high accuracy at a large computational cost. This work develops a combined source, mask and pupil optimization (SMPO) approach by taking advantage of the fact that pupil phase manipulation is capable of partially compensating for mask topography effects. We first design the pupil wavefront function by incorporating primary and secondary spherical aberration through the coefficients of the Zernike polynomials, and achieve optimal source-mask pair under the condition of aberrated pupil. Evaluations against conventional source mask optimization (SMO) without incorporating pupil aberrations show that SMPO provides improved performance in terms of pattern fidelity and process window sizes.

Low surface energy polymeric release coating for improved contact print lithography

NASA Astrophysics Data System (ADS)

Mancini, David P.; Resnick, Douglas J.; Gehoski, Kathleen A.; Popovich, Laura L.; Chang, Daniel

2002-03-01

Contact printing has been used for decades in many various lithography applications in the microelectronic industry. While vacuum contact printing processes offer sub-micron resolution and high throughput, they often suffer from some important drawbacks. One of the most common problems is degradation in both resolution and defect density which occurs when the same mask si used for multiple exposures without frequent mask cleans. This is largely due to the relatively high surface energy of both quartz and chrome and the tendency of most photoresists to adhere to these surfaces. As a result, when a mask and wafer are pressed into intimate contact, resist will tend to stick to the mask creating a defect on the wafer, effectively propagating defects to subsequent wafers. In this study, DuPont Teflon AF 1601S is used as a photomask coating and evaluated for its ability to act as a release agent and reduce defects while maintaining resolution for multiple exposures. Teflon AF is an amorphous, transparent, low surface energy, polymeric material that can be spin coated into a thin conformal film. Tests have shown that when using an uncoated mask in vacuum contact, resolution of 0.75 micrometers dense lines is severely degraded after less than 10 consecutive exposures. However, when the mask is coated, 0.75 micrometers dense lines were successfully resolved using vacuum contact for over 200 exposures without cleaning. In addition, it has been demonstrated that Teflon AF coatings impart to a mask a self-cleaning capability, since particles tend to stick to the photoresist rather than the mask. A coated mask, which was purposefully contaminated with particulates, resolved 0.75 micrometers dense lines on all but the first wafer of a series of 25 consecutive exposures. The patented mask releases layer process has successfully been demonstrated with a positive novolak resist. Additional data which describes the system chemistry, dilution and coating process, and film morphology are also presented.

Electron-beam Induced Processes and their Applicability to Mask Repair

NASA Astrophysics Data System (ADS)

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

2002-12-01

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

Communication masking in marine mammals: A review and research strategy.

PubMed

Erbe, Christine; Reichmuth, Colleen; Cunningham, Kane; Lucke, Klaus; Dooling, Robert

2016-02-15

Underwater noise, whether of natural or anthropogenic origin, has the ability to interfere with the way in which marine mammals receive acoustic signals (i.e., for communication, social interaction, foraging, navigation, etc.). This phenomenon, termed auditory masking, has been well studied in humans and terrestrial vertebrates (in particular birds), but less so in marine mammals. Anthropogenic underwater noise seems to be increasing in parts of the world's oceans and concerns about associated bioacoustic effects, including masking, are growing. In this article, we review our understanding of masking in marine mammals, summarise data on marine mammal hearing as they relate to masking (including audiograms, critical ratios, critical bandwidths, and auditory integration times), discuss masking release processes of receivers (including comodulation masking release and spatial release from masking) and anti-masking strategies of signalers (e.g. Lombard effect), and set a research framework for improved assessment of potential masking in marine mammals. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

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

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),…

Orion Emergency Mask Approach

NASA Technical Reports Server (NTRS)

Tuan, George C.; Graf, John C.

2008-01-01

Emergency mask approach on Orion poses a challenge to the traditional Shuttle or Station approaches. Currently, in the case of a fire or toxic spill event, the crew utilizes open loop oxygen masks that provide the crew with oxygen to breath, but also dumps the exhaled oxygen into the cabin. For Orion, with a small cabin volume, the extra oxygen will exceed the flammability limit within a short period of time, unless a nitrogen purge is also provided. Another approach to a fire or toxic spill event is the use of a filtering emergency masks. These masks utilize some form of chemical beds to scrub the air clean of toxic providing the crew safe breathing air for a period without elevating the oxygen level in the cabin. Using the masks and a form of smoke-eater filter, it may be possible to clean the cabin completely or to a level for safe transition to a space suit to perform a cabin purge. Issues with filters in the past have been the reaction temperature and high breathing resistance. Development in a new form of chemical filters has shown promise to make the filtering approach feasible.

Orion Emergency Mask Approach

NASA Technical Reports Server (NTRS)

Tuan, George C.; Graf, John C.

2009-01-01

Emergency mask approach on Orion poses a challenge to the traditional Shuttle or Station approaches. Currently, in the case of a fire or toxic spill event, the crew utilizes open loop oxygen masks that provide the crew with oxygen to breath, but also dumps the exhaled oxygen into the cabin. For Orion, with a small cabin volume, the extra oxygen will exceed the flammability limit within a short period of time, unless a nitrogen purge is also provided. Another approach to a fire or toxic spill event is the use of a filtering emergency masks. These masks utilize some form of chemical beds to scrub the air clean of toxic providing the crew safe breathing air for a period without elevating the oxygen level in the cabin. Using the masks and a form of smoke-eater filter, it may be possible to clean the cabin completely or to a level for safe transition to a space suit to perform a cabin purge. Issues with filters in the past have been the reaction time, breakthroughs, and high breathing resistance. Development in a new form of chemical filters has shown promise to make the filtering approach feasible.

Coatings masking in near, medium, and far infrared used for ship camouflage

NASA Astrophysics Data System (ADS)

Milewski, S.; Dulski, R.; Kastek, M.; Trzaskawka, P.; Barela, J.; Firmanty, K.

2011-11-01

The increasing range of naval engagements results in development of camouflages applied on warships that mask their signatures first in visible and next in and IR spectra. Camouflage applied on warships that mask their IR signatures is one of the most basic countermeasure methods against attacks by heat-seeking missiles. A set of special coatings applied to the ship's hull allows misidentification by enemies weapon and so make the ship harder to destroy. Thus the knowledge on actual thermal contrast between the ship and surrounding background is required in order to provide an effective antimissile defense. The paper presents selected aspects related to ship's camouflage realized by altering its thermal signature as well as the results of radiometric measurement of thermal radiation of IR-masking coatings. Measurements were performed using IR imaging spectrometers in near, medium and far infrared spectra. The presented measurement results constitute the basis for the assessment of the effectiveness of IR masking methods and additionally provide the opportunity to effectively simulate the properties of masking coatings and further to optimize their radiometric properties in the infrared range.

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

Henry, Michael David; Young, Travis R.; Griffin, Ben

Here, this work reports the utilization of a recently developed film, ScAlN, as a silicon etch mask offering significant improvements in high etch selectivity to silicon. Utilization of ScAlN as a fluorine chemistry based deep reactive ion etch mask demonstrated etch selectivity at 23 550:1, four times better than AlN, 11 times better than Al 2O 3, and 148 times better than silicon dioxide with significantly less resputtering at high bias voltage than either Al 2O 3 or AlN. Ellipsometry film thickness measurements show less than 0.3 nm/min mask erosion rates for ScAlN. Micromasking of resputtered Al for Al 2Omore » 3, AlN, and ScAlN etch masks is also reported here, utilizing cross-sectional scanning electron microscope and confocal microscope roughness measurements. With lower etch bias, the reduced etch rate can be optimized to achieve a trench bottom surface roughness that is comparable to SiO 2 etch masks. Etch mask selectivity enabled by ScAlN is likely to make significant improvements in microelectromechanical systems, wafer level packaging, and plasma dicing of silicon.« less

Inverse Tomo-Lithography for Making Microscopic 3D Parts

NASA Technical Reports Server (NTRS)

White, Victor; Wiberg, Dean

2003-01-01

According to a proposal, basic x-ray lithography would be extended to incorporate a technique, called inverse tomography, that would enable the fabrication of microscopic three-dimensional (3D) objects. The proposed inverse tomo-lithographic process would make it possible to produce complex shaped, submillimeter-sized parts that would be difficult or impossible to make in any other way. Examples of such shapes or parts include tapered helices, paraboloids with axes of different lengths, and even Archimedean screws that could serve as rotors in microturbines. The proposed inverse tomo-lithographic process would be based partly on a prior microfabrication process known by the German acronym LIGA (lithographie, galvanoformung, abformung, which means lithography, electroforming, molding). In LIGA, one generates a precise, high-aspect ratio pattern by exposing a thick, x-ray-sensitive resist material to an x-ray beam through a mask that contains the pattern. One can electrodeposit metal into the developed resist pattern to form a precise metal part, then dissolve the resist to free the metal. Aspect ratios of 100:1 and patterns into resist thicknesses of several millimeters are possible.

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

NASA Astrophysics Data System (ADS)

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

2005-11-01

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

Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

DOEpatents

Li, Ting [Ventura, CA

2011-04-26

The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

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…

Masked Repetition Priming Treatment for Anomia

ERIC Educational Resources Information Center

Silkes, JoAnn P.

2018-01-01

Purpose: Masked priming has been suggested as a way to directly target implicit lexical retrieval processes in aphasia. This study was designed to investigate repeated use of masked repetition priming to improve picture naming in individuals with anomia due to aphasia. Method: A single-subject, multiple-baseline design was used across 6 people…

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…

Sandwich masking eliminates both visual awareness of faces and face-specific brain activity through a feedforward mechanism.

PubMed

Harris, Joseph A; Wu, Chien-Te; Woldorff, Marty G

2011-06-07

It is generally agreed that considerable amounts of low-level sensory processing of visual stimuli can occur without conscious awareness. On the other hand, the degree of higher level visual processing that occurs in the absence of awareness is as yet unclear. Here, event-related potential (ERP) measures of brain activity were recorded during a sandwich-masking paradigm, a commonly used approach for attenuating conscious awareness of visual stimulus content. In particular, the present study used a combination of ERP activation contrasts to track both early sensory-processing ERP components and face-specific N170 ERP activations, in trials with versus without awareness. The electrophysiological measures revealed that the sandwich masking abolished the early face-specific N170 neural response (peaking at ~170 ms post-stimulus), an effect that paralleled the abolition of awareness of face versus non-face image content. Furthermore, however, the masking appeared to render a strong attenuation of earlier feedforward visual sensory-processing signals. This early attenuation presumably resulted in insufficient information being fed into the higher level visual system pathways specific to object category processing, thus leading to unawareness of the visual object content. These results support a coupling of visual awareness and neural indices of face processing, while also demonstrating an early low-level mechanism of interference in sandwich masking.

Uncertainty in the visibility mask of a survey and its effects on the clustering of biased tracers

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

Colavincenzo, M.; Monaco, P.; Borgani, S.

The forecasted accuracy of upcoming surveys of large-scale structure cannot be achieved without a proper quantification of the error induced by foreground removal (or other systematics like 0-point photometry offset). Because these errors are highly correlated on the sky, their influence is expected to be especially important at very large scales, at and beyond the first Baryonic Acoustic Oscillation (BAO). In this work we quantify how the uncertainty in the visibility mask of a survey, that gives the survey depth in a specific sky area, influences the measured power spectrum of a sample of tracers of the density field andmore » its covariance matrix. We start from a very large set of 10,000 catalogs of dark matter (DM) halos in periodic cosmological boxes, produced with the PINOCCHIO approximate method. To make an analytic approach feasible, we assume luminosity-independent halo bias and an idealized geometry for the visibility mask, that is constant in square tiles of physical length l ; this should be interpreted as the projection, at the observation redshift, of the angular correlation scale of the foreground residuals. We find that the power spectrum of these biased tracers can be expressed as the sum of a cosmological term, a mask term and a term involving their convolution. The mask and convolution terms scale like P ∝ l {sup 2}σ {sub A} {sup 2}, where σ {sub A} {sup 2} is the variance of the uncertainty on the visibility mask. With l = 30−100 Mpc/ h and σ {sub A} = 5−20%, the mask term can be significant at k ∼ 0.01−0.1 h /Mpc, and the convolution term can amount to ∼ 1−10% of the total. The influence of mask uncertainty on power spectrum covariance is more complicated: the coupling of the convolution term with the other two gives rise to several mixed terms, that we quantify by difference using the mock catalogs. These are found to be of the same order of the mask covariance, and to introduce non-diagonal terms at large scales. As a consequence, the power spectrum covariance matrix cannot be expressed as the sum of a cosmological and of a mask term. More realistic settings (realistic foregrounds, luminosity-dependent bias) make the analytical approach not feasible, and the problem requires on the one hand usage of extended sets of mock catalogs, on the other hand detailed knowledge of the correlations among errors in the visibility masks. Our results lie down the theoretical bases to quantify the impact that uncertainties in the mask calibration have on the derivation of cosmological constraints from large spectroscopic surveys.« less

Development of template and mask replication using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Brooks, Cynthia; Selinidis, Kosta; Doyle, Gary; Brown, Laura; LaBrake, Dwayne; Resnick, Douglas J.; Sreenivasan, S. V.

2010-09-01

The Jet and Flash Imprint Lithography (J-FILTM)1-7 process uses drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for memory markets including Flash memory and patterned media for hard disk drives. It is anticipated that the lifetime of a single template (for patterned media) or mask (for semiconductor) will be on the order of 104 - 105 imprints. This suggests that tens of thousands of templates/masks will be required. It is not feasible to employ electronbeam patterning directly to deliver these volumes. Instead, a "master" template - created by directly patterning with an electron-beam tool - will be replicated many times with an imprint lithography tool to produce the required supply of "working" templates/masks. In this paper, we review the development of the pattern transfer process for both template and mask replicas. Pattern transfer of resolutions down to 25nm has been demonstrated for bit patterned media replication. In addition, final resolution on a semiconductor mask of 28nm has been confirmed. The early results on both etch depth and CD uniformity are promising, but more extensive work is required to characterize the pattern transfer process.

Backward masked fearful faces enhance contralateral occipital cortical activity for visual targets within the spotlight of attention

PubMed Central

Reinke, Karen S.; LaMontagne, Pamela J.; Habib, Reza

2011-01-01

Spatial attention has been argued to be adaptive by enhancing the processing of visual stimuli within the ‘spotlight of attention’. We previously reported that crude threat cues (backward masked fearful faces) facilitate spatial attention through a network of brain regions consisting of the amygdala, anterior cingulate and contralateral visual cortex. However, results from previous functional magnetic resonance imaging (fMRI) dot-probe studies have been inconclusive regarding a fearful face-elicited contralateral modulation of visual targets. Here, we tested the hypothesis that the capture of spatial attention by crude threat cues would facilitate processing of subsequently presented visual stimuli within the masked fearful face-elicited ‘spotlight of attention’ in the contralateral visual cortex. Participants performed a backward masked fearful face dot-probe task while brain activity was measured with fMRI. Masked fearful face left visual field trials enhanced activity for spatially congruent targets in the right superior occipital gyrus, fusiform gyrus and lateral occipital complex, while masked fearful face right visual field trials enhanced activity in the left middle occipital gyrus. These data indicate that crude threat elicited spatial attention enhances the processing of subsequent visual stimuli in contralateral occipital cortex, which may occur by lowering neural activation thresholds in this retinotopic location. PMID:20702500

Structural colour printing from a reusable generic nanosubstrate masked for the target image

NASA Astrophysics Data System (ADS)

Rezaei, M.; Jiang, H.; Kaminska, B.

2016-02-01

Structural colour printing has advantages over traditional pigment-based colour printing. However, the high fabrication cost has hindered its applications in printing large-area images because each image requires patterning structural pixels in nanoscale resolution. In this work, we present a novel strategy to print structural colour images from a pixelated substrate which is called a nanosubstrate. The nanosubstrate is fabricated only once using nanofabrication tools and can be reused for printing a large quantity of structural colour images. It contains closely packed arrays of nanostructures from which red, green, blue and infrared structural pixels can be imprinted. To print a target colour image, the nanosubstrate is first covered with a mask layer to block all the structural pixels. The mask layer is subsequently patterned according to the target colour image to make apertures of controllable sizes on top of the wanted primary colour pixels. The masked nanosubstrate is then used as a stamp to imprint the colour image onto a separate substrate surface using nanoimprint lithography. Different visual colours are achieved by properly mixing the red, green and blue primary colours into appropriate ratios controlled by the aperture sizes on the patterned mask layer. Such a strategy significantly reduces the cost and complexity of printing a structural colour image from lengthy nanoscale patterning into high throughput micro-patterning and makes it possible to apply structural colour printing in personalized security features and data storage. In this paper, nanocone array grating pixels were used as the structural pixels and the nanosubstrate contains structures to imprint the nanocone arrays. Laser lithography was implemented to pattern the mask layer with submicron resolution. The optical properties of the nanocone array gratings are studied in detail. Multiple printed structural colour images with embedded covert information are demonstrated.

Method for growing low defect, high purity crystalline layers utilizing lateral overgrowth of a patterned mask

NASA Technical Reports Server (NTRS)

Morrison, Andrew D. (Inventor); Daud, Taher (Inventor)

1986-01-01

A method for growing a high purity, low defect layer of semiconductor is described. This method involves depositing a patterned mask of a material impervious to impurities of the semiconductor on a surface of a blank. When a layer of semiconductor is grown on the mask, the semiconductor will first grow from the surface portions exposed by the openings in the mask and will bridge the connecting portions of the mask to form a continuous layer having improved purity, since only the portions overlying the openings are exposed to defects and impurities. The process can be iterated and the mask translated to further improve the quality of grown layers.

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

NASA Astrophysics Data System (ADS)

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

2012-03-01

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

Time-Frequency Masking for Speech Separation and Its Potential for Hearing Aid Design

PubMed Central

Wang, DeLiang

2008-01-01

A new approach to the separation of speech from speech-in-noise mixtures is the use of time-frequency (T-F) masking. Originated in the field of computational auditory scene analysis, T-F masking performs separation in the time-frequency domain. This article introduces the T-F masking concept and reviews T-F masking algorithms that separate target speech from either monaural or binaural mixtures, as well as microphone-array recordings. The review emphasizes techniques that are promising for hearing aid design. This article also surveys recent studies that evaluate the perceptual effects of T-F masking techniques, particularly their effectiveness in improving human speech recognition in noise. An assessment is made of the potential benefits of T-F masking methods for the hearing impaired in light of the processing constraints of hearing aids. Finally, several issues pertinent to T-F masking are discussed. PMID:18974204

Fabrication of rectangular cross-sectional microchannels on PMMA with a CO2 laser and underwater fabricated copper mask

NASA Astrophysics Data System (ADS)

Prakash, Shashi; Kumar, Subrata

2017-09-01

CO2 lasers are commonly used for fabricating polymer based microfluidic devices. Despite several key advantages like low cost, time effectiveness, easy to operate and no requirement of clean room facility, CO2 lasers suffer from few disadvantages like thermal bulging, improper dimensional control, difficulty to produce microchannels of other than Gaussian cross sectional shapes and inclined surface walls. Many microfluidic devices require square or rectangular cross-sections which are difficult to produce using normal CO2 laser procedures. In this work, a thin copper sheet of 40 μm was used as a mask above the PMMA (Polymethyl-methacrylate) substrate while fabricating the microchannels utilizing the raster scanning feature of the CO2 lasers. Microchannels with different width dimensions were fabricated utilizing a CO2 laser in with mask and without-mask conditions. A comparison of both the fabricating process has been made. It was found that microchannels with U shape cross section and rectangular cross-section can efficiently be produced using the with mask technique. In addition to this, this technique can provide perfect dimensional control and better surface quality of the microchannel walls. Such a microchannel fabrication process do not require any post-processing. The fabrication of mask using a nanosecond fiber laser has been discussed in details. An underwater laser fabrication method was adopted to overcome heat related defects in mask preparation. Overall, the technique was found to be easy to adopt and significant improvements were observed in microchannel fabrication.

Application of the unified mask data format based on OASIS for VSB EB writers

NASA Astrophysics Data System (ADS)

Suzuki, Toshio; Hirumi, Junji; Suga, Osamu

2005-11-01

Mask data preparation (MDP) for modern mask manufacturing becomes a complex process because many kinds of EB data formats are used in mask makers and EB data files continue to become bigger by the application of RET. Therefore we developed a unified mask pattern data format named "OASIS.VSB1" and a job deck format named "MALY2" for Variable-Shaped-Beam (VSB) EB writers. OASIS.VSB is the mask pattern data format based on OASISTM 3 (Open Artwork System Interchange Standard) released as a successive format to GDSII by SEMI. We defined restrictions on OASIS for VSB EB writers to input OASIS.VSB data directly to VSB EB writers just like the native EB data. OASIS.VSB specification and MALY specification have been disclosed to the public and will become a SEMI standard in the near future. We started to promote the spread activities of OASIS.VSB and MALY. For practical use of OASIS.VSB and MALY, we are discussing the infrastructure system of MDP processing using OASIS.VSB and MALY with mask makers, VSB EB makers, and device makers. We are also discussing the tools for the infrastructure system with EDA vendors. The infrastructure system will enable TAT, the man-hour, and the cost in MDP to be reduced. In this paper, we propose the plan of the infrastructure system of MDP processing using OASIS.VSB and MALY as an application of OASIS.VSB and MALY.

Less is More: Neural Activity During Very Brief and Clearly Visible Exposure to Phobic Stimuli

PubMed Central

Siegel, Paul; Warren, Richard; Wang, Zhishun; Yang, Jie; Cohen, Don; Anderson, Jason F.; Murray, Lilly; Peterson, Bradley S.

2017-01-01

Research on automatic processes in emotion has focused almost exclusively on the provocation of fear responses. We have shown, in contrast, that the repeated presentation of masked feared images reduces avoidance of a live tarantula by spider-phobic participants. We investigated the neural basis for these adaptive effects of masked exposure. We identified 21 spider-phobic and 21 control participants using a psychiatric interview, fear questionnaire, and approach behavior towards a live tarantula. They received each of three conditions: (1) very brief exposure (VBE) to masked images of spiders; (2) clearly visible exposure (CVE) to spiders; and (3) masked images of flowers (control). Only VBE to masked spiders generated neural activity more strongly in phobic than in control participants, within subcortical fear, attention, higher-order language, and vision systems. Counter-intuitively, CVE to the same spiders generated stronger neural activity in control rather than phobic participants within these and other systems. VBE activated regions that support fear processing in phobic participants without causing them to experience fear consciously. CVE, by contrast, deactivated regions supporting fear regulation and caused phobic participants to experience fear. Activations by CVE to spiders correlated with fear ratings - explicit fear. Activations by VBE to masked spiders correlated with color-naming interference of spider words – implicit fear. These multiple dissociations between the effects of VBE and CVE to spiders suggest that limiting awareness of exposure to phobic stimuli through visual masking paradoxically facilitates their processing, while simultaneously minimizing the experience of fear. PMID:28165171

Thiazine-2-thiones as Masked 1-Azadienes in Cascade Dimerization Reactions).

PubMed

Kruithof, Art; Vande Velde, Christophe M L; Ruijter, Eelco; Orru, Romano V A

2017-03-28

We report the unexpected formation of a 1-azadiene dimer from 4,6-diphenyl-3,6-dihydro-2 H -1,3-thiazine-2-thiones under prolonged microwave irradiation. In this manner, thiazine-2-thiones act as "masked" 1-azadiene equivalents, which makes them useful synthetic tools to access complex heterocyclic frameworks. We compare this dimerization with earlier approaches and elaborate on the observed diastereoselectivity.

The effect of foveal and parafoveal masks on the eye movements of older and younger readers.

PubMed

Rayner, Keith; Yang, Jinmian; Schuett, Susanne; Slattery, Timothy J

2014-06-01

In the present study, we examined foveal and parafoveal processing in older compared with younger readers by using gaze-contingent paradigms with 4 conditions. Older and younger readers read sentences in which the text was either a) presented normally, b) the foveal word was masked as soon as it was fixated, c) all of the words to the left of the fixated word were masked, or d) all of the words to the right of the fixated word were masked. Although older and younger readers both found reading when the fixated word was masked quite difficult, the foveal mask increased sentence reading time more than 3-fold (3.4) for the older readers (in comparison with the control condition in which the sentence was presented normally) compared with the younger readers who took 1.3 times longer to read sentences in the foveal mask condition (in comparison with the control condition). The left and right parafoveal masks did not disrupt reading as severely as the foveal mask, though the right mask was more disruptive than the left mask. Also, there was some indication that the younger readers found the right mask condition relatively more disruptive than the left mask condition. PsycINFO Database Record (c) 2014 APA, all rights reserved.

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.

Football Face-Mask Removal With a Cordless Screwdriver on Helmets Used for at Least One Season of Play

PubMed Central

Decoster, Laura C; Shirley, Chandra P; Swartz, Erik E

2005-01-01

Context: The Inter-Association Task Force for the Appropriate Care of the Spine-Injured Athlete recommends leaving a football player's helmet in place and removing the face mask from the helmet “as quickly as possible and with as little movement of the head and neck as possible.” Although 2 groups have studied face-mask removal from new equipment, to our knowledge no researchers have investigated equipment that has been previously used. A full season of play may have a significant effect on football equipment and its associated hardware. Countless impacts, weather, playing surfaces, sweat, and other unforeseen or unknown variables might make the face-mask removal process more difficult on equipment that has been used. Objective: To determine the percentage of face masks that we could unscrew, with a cordless screwdriver, from football helmets used for a full season. Design: Cross-sectional. Setting: Three New England high schools. Patients or Other Participants: All football helmets used at 3 local high schools were tested (n = 222, mean games, 9.7 ± 1.2; mean practice weeks, 13.7 ± 1.2). Intervention(s): Each helmet was secured to a board, and a cordless screwdriver was used to attempt to remove all 4 screws attaching the face mask to the helmet. Main Outcome Measure(s): Variables included overall success or failure, time required for face-mask removal, and success by screw location. Data were analyzed with χ2, analysis of variance, and Tamhane post hoc tests. Results: Overall, 832 (94%) of 885 screws were unscrewed, and 183 (82.4%) of 222 face masks were removed. Mean removal time was 26.9 ± 5.83 seconds. Face-mask removal success was significantly different between school 1 (24 [52.2%] of 46) and schools 2 (84 [91.3%] of 92) and 3 (75 [89.3%] of 84; F2,219 = 24.608; P < .001). The removal success rate was significantly higher at top screws (98%) than at screws adjacent to ear holes (90%) (P < .001). Conclusions: Based on our results and previous findings that demonstrated quicker access time and reduced head movement associated with the use of the screwdriver compared with cutting tools, the former may be a good tool for face-mask removal. However, an appropriate cutting tool must be immediately available should the screwdriver fail. Helmet hardware adjacent to ear holes was more vulnerable to failure, perhaps because it is protected by less padding than the top hardware. Possible causes of the higher failure rate at school 1 are the use of hardware materials subject to rust and corrosion and differences in helmet brand; these areas warrant future research and rules consideration. PMID:16284636

ArF halftone PSM cleaning process optimization for next-generation lithography

NASA Astrophysics Data System (ADS)

Son, Yong-Seok; Jeong, Seong-Ho; Kim, Jeong-Bae; Kim, Hong-Seok

2000-07-01

ArF lithography which is expected for the next generation optical lithography is adapted for 0.13 micrometers design-rule and beyond. ArF half-tone phase shift mask (HT PSM) will be applied as 1st generation of ArF lithography. Also ArF PSM cleaning demands by means of tighter controls related to phase angle, transmittance and contamination on the masks. Phase angle on ArF HT PSM should be controlled within at least +/- 3 degree and transmittance controlled within at least +/- 3 percent after cleaning process and pelliclization. In the cleaning process of HT PSM, requires not only the remove the particle on mask, but also control to half-tone material for metamorphosis. Contamination defects on the Qz of half tone type PSM is not easy to remove on the photomask surface. New technology and methods of cleaning will be developed in near future, but we try to get out for limit contamination on the mask, without variation of phase angle and transmittance after cleaning process.

SMIF capability at Intel Mask Operation improves yield

NASA Astrophysics Data System (ADS)

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

2003-08-01

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

Utilizing Hierarchical Segmentation to Generate Water and Snow Masks to Facilitate Monitoring Change with Remotely Sensed Image Data

NASA Technical Reports Server (NTRS)

Tilton, James C.; Lawrence, William T.; Plaza, Antonio J.

2006-01-01

The hierarchical segmentation (HSEG) algorithm is a hybrid of hierarchical step-wise optimization and constrained spectral clustering that produces a hierarchical set of image segmentations. This segmentation hierarchy organizes image data in a manner that makes the image's information content more accessible for analysis by enabling region-based analysis. This paper discusses data analysis with HSEG and describes several measures of region characteristics that may be useful analyzing segmentation hierarchies for various applications. Segmentation hierarchy analysis for generating landwater and snow/ice masks from MODIS (Moderate Resolution Imaging Spectroradiometer) data was demonstrated and compared with the corresponding MODIS standard products. The masks based on HSEG segmentation hierarchies compare very favorably to the MODIS standard products. Further, the HSEG based landwater mask was specifically tailored to the MODIS data and the HSEG snow/ice mask did not require the setting of a critical threshold as required in the production of the corresponding MODIS standard product.

Unconscious and out of control: subliminal priming is insensitive to observer expectations.

PubMed

Cressman, Erin K; Lam, Melanie Y; Franks, Ian M; Enns, James T; Chua, Romeo

2013-09-01

We asked whether the influence of an invisible prime on movement is dependent on conscious movement expectations. Participants reached to a central target, which triggered a directional prime-mask arrow sequence. Participants were instructed that the visible arrows (masks) would most often signal a movement modification in a specific (biased) direction. Kinematic analyses revealed that responses to the visible mask were influenced by participants' intentional bias, as movements were fastest when the more probable mask was displayed. In addition, responses were influenced by the invisible prime without regard to its relationship to the more probable mask. Analysis of the time of initial trajectory modifications revealed that both primes influenced responses in a similar manner after accounting for participants' bias. These results imply that invisible stimuli automatically activate their associated responses and that unconscious priming of the motor system is insensitive to the conscious expectations of the participant making the pointing movements. Copyright © 2013 Elsevier Inc. All rights reserved.

Cycle time reduction by Html report in mask checking flow

NASA Astrophysics Data System (ADS)

Chen, Jian-Cheng; Lu, Min-Ying; Fang, Xiang; Shen, Ming-Feng; Ma, Shou-Yuan; Yang, Chuen-Huei; Tsai, Joe; Lee, Rachel; Deng, Erwin; Lin, Ling-Chieh; Liao, Hung-Yueh; Tsai, Jenny; Bowhill, Amanda; Vu, Hien; Russell, Gordon

2017-07-01

The Mask Data Correctness Check (MDCC) is a reticle-level, multi-layer DRC-like check evolved from mask rule check (MRC). The MDCC uses extended job deck (EJB) to achieve mask composition and to perform a detailed check for positioning and integrity of each component of the reticle. Different design patterns on the mask will be mapped to different layers. Therefore, users may be able to review the whole reticle and check the interactions between different designs before the final mask pattern file is available. However, many types of MDCC check results, such as errors from overlapping patterns usually have very large and complex-shaped highlighted areas covering the boundary of the design. Users have to load the result OASIS file and overlap it to the original database that was assembled in MDCC process on a layout viewer, then search for the details of the check results. We introduce a quick result-reviewing method based on an html format report generated by Calibre® RVE. In the report generation process, we analyze and extract the essential part of result OASIS file to a result database (RDB) file by standard verification rule format (SVRF) commands. Calibre® RVE automatically loads the assembled reticle pattern and generates screen shots of these check results. All the processes are automatically triggered just after the MDCC process finishes. Users just have to open the html report to get the information they need: for example, check summary, captured images of results and their coordinates.

System and methods for determining masking signals for applying empirical mode decomposition (EMD) and for demodulating intrinsic mode functions obtained from application of EMD

DOEpatents

Senroy, Nilanjan [New Delhi, IN; Suryanarayanan, Siddharth [Littleton, CO

2011-03-15

A computer-implemented method of signal processing is provided. The method includes generating one or more masking signals based upon a computed Fourier transform of a received signal. The method further includes determining one or more intrinsic mode functions (IMFs) of the received signal by performing a masking-signal-based empirical mode decomposition (EMD) using the at least one masking signal.

Do different perceptual task sets modulate electrophysiological correlates of masked visuomotor priming? Attention to shape and color put to the test.

PubMed

Zovko, Monika; Kiefer, Markus

2013-02-01

According to classical theories, automatic processes operate independently of attention. Recent evidence, however, shows that masked visuomotor priming, an example of an automatic process, depends on attention to visual form versus semantics. In a continuation of this approach, we probed feature-specific attention within the perceptual domain and tested in two event-related potential (ERP) studies whether masked visuomotor priming in a shape decision task specifically depends on attentional sensitization of visual pathways for shape in contrast to color. Prior to the masked priming procedure, a shape or a color decision task served to induce corresponding task sets. ERP analyses revealed visuomotor priming effects over the occipitoparietal scalp only after the shape, but not after the color induction task. Thus, top-down control coordinates automatic processing streams in congruency with higher-level goals even at a fine-grained level. Copyright © 2012 Society for Psychophysiological Research.

EUVL mask patterning with blanks from commercial suppliers

NASA Astrophysics Data System (ADS)

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

2004-12-01

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

Near-field photochemical and radiation-induced chemical fabrication of nanopatterns of a self-assembled silane monolayer

PubMed Central

Hentschel, Carsten; Fontein, Florian; Stegemann, Linda; Hoeppener, Christiane; Fuchs, Harald; Hoeppener, Stefanie

2014-01-01

Summary A general concept for parallel near-field photochemical and radiation-induced chemical processes for the fabrication of nanopatterns of a self-assembled monolayer (SAM) of (3-aminopropyl)triethoxysilane (APTES) is explored with three different processes: 1) a near-field photochemical process by photochemical bleaching of a monomolecular layer of dye molecules chemically bound to an APTES SAM, 2) a chemical process induced by oxygen plasma etching as well as 3) a combined near-field UV-photochemical and ozone-induced chemical process, which is applied directly to an APTES SAM. All approaches employ a sandwich configuration of the surface-supported SAM, and a lithographic mask in form of gold nanostructures fabricated through colloidal sphere lithography (CL), which is either exposed to visible light, oxygen plasma or an UV–ozone atmosphere. The gold mask has the function to inhibit the photochemical reactions by highly localized near-field interactions between metal mask and SAM and to inhibit the radiation-induced chemical reactions by casting a highly localized shadow. The removal of the gold mask reveals the SAM nanopattern. PMID:25247126

Process research of non-cz silicon material. Low cost solar array project, cell and module formation research area

NASA Technical Reports Server (NTRS)

1982-01-01

Liquid diffusion masks and liquid applied dopants to replace the CVD Silox masking and gaseous diffusion operations specified for forming junctions in the Westinghouse baseline process sequence for producing solar cells from dendritic web silicon were investigated.

Coherent optical processing using noncoherent light after source masking.

PubMed

Boopathi, V; Vasu, R M

1992-01-10

Coherent optical processing starting with spatially noncoherent illumination is described. Good spatial coherence is introduced in the far field by modulating a noncoherent source when masks with sharp autocorrelation are used. The far-field mutual coherence function of light is measured and it is seen that, for the masks and the source size used here, we get a fairly large area over which the mutual coherence function is high and flat. We demonstrate traditional coherent processing operations such as Fourier transformation and image deblurring when coherent light that is produced in the above fashion is used. A coherence-redundancy merit function is defined for this type of processing system. It is experimentally demonstrated that the processing system introduced here has superior blemish tolerance compared with a traditional processor that uses coherent illumination.

Improving the CD linearity and proximity performance of photomasks written on the Sigma7500-II DUV laser writer through embedded OPC

NASA Astrophysics Data System (ADS)

Österberg, Anders; Ivansen, Lars; Beyerl, Angela; Newman, Tom; Bowhill, Amanda; Sahouria, Emile; Schulze, Steffen

2007-10-01

Optical proximity correction (OPC) is widely used in wafer lithography to produce a printed image that best matches the design intent while optimizing CD control. OPC software applies corrections to the mask pattern data, but in general it does not compensate for the mask writer and mask process characteristics. The Sigma7500-II deep-UV laser mask writer projects the image of a programmable spatial light modulator (SLM) using partially coherent optics similar to wafer steppers, and the optical proximity effects of the mask writer are in principle correctable with established OPC methods. To enhance mask patterning, an embedded OPC function, LinearityEqualize TM, has been developed for the Sigma7500- II that is transparent to the user and which does not degrade mask throughput. It employs a Calibre TM rule-based OPC engine from Mentor Graphics, selected for the computational speed necessary for mask run-time execution. A multinode cluster computer applies optimized table-based CD corrections to polygonized pattern data that is then fractured into an internal writer format for subsequent data processing. This embedded proximity correction flattens the linearity behavior for all linewidths and pitches, which targets to improve the CD uniformity on production photomasks. Printing results show that the CD linearity is reduced to below 5 nm for linewidths down to 200 nm, both for clear and dark and for isolated and dense features, and that sub-resolution assist features (SRAF) are reliably printed down to 120 nm. This reduction of proximity effects for main mask features and the extension of the practical resolution for SRAFs expands the application space of DUV laser mask writing.

Advances in low-defect multilayers for EUVL mask blanks

NASA Astrophysics Data System (ADS)

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

2002-07-01

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

Schizophrenia alters intra-network functional connectivity in the caudate for detecting speech under informational speech masking conditions.

PubMed

Zheng, Yingjun; Wu, Chao; Li, Juanhua; Li, Ruikeng; Peng, Hongjun; She, Shenglin; Ning, Yuping; Li, Liang

2018-04-04

Speech recognition under noisy "cocktail-party" environments involves multiple perceptual/cognitive processes, including target detection, selective attention, irrelevant signal inhibition, sensory/working memory, and speech production. Compared to health listeners, people with schizophrenia are more vulnerable to masking stimuli and perform worse in speech recognition under speech-on-speech masking conditions. Although the schizophrenia-related speech-recognition impairment under "cocktail-party" conditions is associated with deficits of various perceptual/cognitive processes, it is crucial to know whether the brain substrates critically underlying speech detection against informational speech masking are impaired in people with schizophrenia. Using functional magnetic resonance imaging (fMRI), this study investigated differences between people with schizophrenia (n = 19, mean age = 33 ± 10 years) and their matched healthy controls (n = 15, mean age = 30 ± 9 years) in intra-network functional connectivity (FC) specifically associated with target-speech detection under speech-on-speech-masking conditions. The target-speech detection performance under the speech-on-speech-masking condition in participants with schizophrenia was significantly worse than that in matched healthy participants (healthy controls). Moreover, in healthy controls, but not participants with schizophrenia, the strength of intra-network FC within the bilateral caudate was positively correlated with the speech-detection performance under the speech-masking conditions. Compared to controls, patients showed altered spatial activity pattern and decreased intra-network FC in the caudate. In people with schizophrenia, the declined speech-detection performance under speech-on-speech masking conditions is associated with reduced intra-caudate functional connectivity, which normally contributes to detecting target speech against speech masking via its functions of suppressing masking-speech signals.

3D-printed coded apertures for x-ray backscatter radiography

NASA Astrophysics Data System (ADS)

Muñoz, André A. M.; Vella, Anna; Healy, Matthew J. F.; Lane, David W.; Jupp, Ian; Lockley, David

2017-09-01

Many different mask patterns can be used for X-ray backscatter imaging using coded apertures, which can find application in the medical, industrial and security sectors. While some of these patterns may be considered to have a self-supporting structure, this is not the case for some of the most frequently used patterns such as uniformly redundant arrays or any pattern with a high open fraction. This makes mask construction difficult and usually requires a compromise in its design by drilling holes or adopting a no two holes touching version of the original pattern. In this study, this compromise was avoided by 3D printing a support structure that was then filled with a radiopaque material to create the completed mask. The coded masks were manufactured using two different methods, hot cast and cold cast. Hot casting involved casting a bismuth alloy at 80°C into the 3D printed acrylonitrile butadiene styrene mould which produced an absorber with density of 8.6 g cm-3. Cold casting was undertaken at room temperature, when a tungsten/epoxy composite was cast into a 3D printed polylactic acid mould. The cold cast procedure offered a greater density of around 9.6 to 10 g cm-3 and consequently greater X-ray attenuation. It was also found to be much easier to manufacture and more cost effective. A critical review of the manufacturing procedure is presented along with some typical images. In both cases the 3D printing process allowed square apertures to be created avoiding their approximation by circular holes when conventional drilling is used.

A novel approach to mask defect inspection

NASA Astrophysics Data System (ADS)

Sagiv, Amir; Shirman, Yuri; Mangan, Shmoolik

2008-10-01

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

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

NASA Astrophysics Data System (ADS)

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

2012-11-01

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

Recovery of a crowded object by masking the flankers: Determining the locus of feature integration

PubMed Central

Chakravarthi, Ramakrishna; Cavanagh, Patrick

2009-01-01

Object recognition is a central function of the visual system. As a first step, the features of an object are registered; these independently encoded features are then bound together to form a single representation. Here we investigate the locus of this “feature integration” by examining crowding, a striking breakdown of this process. Crowding, an inability to identify a peripheral target surrounded by flankers, results from “excessive integration” of target and flanker features. We presented a standard crowding display with a target C flanked by four flanker C's in the periphery. We then masked only the flankers (but not the target) with one of three kinds of masks—noise, metacontrast, and object substitution—each of which interferes at progressively higher levels of visual processing. With noise and metacontrast masks (low-level masking), the crowded target was recovered, whereas with object substitution masks (high-level masking), it was not. This places a clear upper bound on the locus of interference in crowding suggesting that crowding is not a low-level phenomenon. We conclude that feature integration, which underlies crowding, occurs prior to the locus of object substitution masking. Further, our results indicate that the integrity of the flankers, but not their identification, is crucial for crowding to occur. PMID:19810785

Managing effects in CD control from PED and PEB in advanced DUV photomask manufacturing using FEP-171 resist

NASA Astrophysics Data System (ADS)

Paulsson, Adisa; Xing, Kezhao; Fosshaug, Hans; Lundvall, Axel; Bjoernberg, Charles; Karlsson, Johan

2005-05-01

A continuing improvement in resist process is a necessity for high-end photomask fabrication. In advanced chemically amplified resist systems the lithographic performance is strongly influenced by diffusion of acid and acid quencher (i.e. bases). Beside the resist properties, e.g. size and volatility of the photoacid, the process conditions play important roles for the diffusion control. Understanding and managing these properties influences lithographic characteristics on the photomask such as CD uniformity, CD and pitch linearity, resolution, substrate contamination, clear-dark bias and iso-dense bias. In this paper we have investigated effects on the lithographic characteristics with respect to post exposure bake conditions, when using the chemically amplified resist FEP-171. We used commercially available mask blanks from the Hoya Mask Blank Division with NTAR7 chrome and an optimized resist thickness for the 248 nm laser tool at 3200Å. The photomasks were exposed on the optical DUV (248nm) Sigma7300 pattern generator. Additionally, we investigated the image stability between exposure and post exposure bake. Unlike in wafer fabrication, photomask writing requires several hours, making the resist susceptible to image blur and acid latent image degradation.

Silicon cells made by self-aligned selective-emitter plasma-etchback process

DOEpatents

Ruby, Douglas S.; Schubert, William K.; Gee, James M.; Zaidi, Saleem H.

2000-01-01

Photovoltaic cells and methods for making them are disclosed wherein the metallized grids of the cells are used to mask portions of cell emitter regions to allow selective etching of phosphorus-doped emitter regions. The preferred etchant is SF.sub.6 or a combination of SF.sub.6 and O.sub.2. This self-aligned selective etching allows for enhanced blue response (versus cells with uniform heavy doping of the emitter) while preserving heavier doping in the region beneath the gridlines needed for low contact resistance. Embodiments are disclosed for making cells with or without textured surfaces. Optional steps include plasma hydrogenation and PECVD nitride deposition, each of which are suited to customized applications for requirements of given cells to be manufactured. The techniques disclosed could replace expensive and difficult alignment methodologies used to obtain selectively etched emitters, and they may be easily integrated with existing plasma processing methods and techniques of the invention may be accomplished in a single plasma-processing chamber.

Photomask quality assessment solution for 90-nm technology node

NASA Astrophysics Data System (ADS)

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

2004-08-01

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

Evaluating automatic attentional capture by self-relevant information.

PubMed

Ocampo, Brenda; Kahan, Todd A

2016-01-01

Our everyday decisions and memories are inadvertently influenced by self-relevant information. For example, we are faster and more accurate at making perceptual judgments about stimuli associated with ourselves, such as our own face or name, as compared with familiar non-self-relevant stimuli. Humphreys and Sui propose a "self-attention network" to account for these effects, wherein self-relevant stimuli automatically capture our attention and subsequently enhance the perceptual processing of self-relevant information. We propose that the masked priming paradigm and continuous flash suppression represent two ways to experimentally examine these controversial claims.

Infrared image construction with computer-generated reflection holograms. [using carbon dioxide laser

NASA Technical Reports Server (NTRS)

Angus, J. C.; Coffield, F. E.; Edwards, R. V.; Mann, J. A., Jr.; Rugh, R. W.; Gallagher, N. C.

1977-01-01

Computer-generated reflection holograms hold substantial promise as a means of carrying out complex machining, marking, scribing, welding, soldering, heat treating, and similar processing operations simultaneously and without moving the work piece or laser beam. In the study described, a photographically reduced transparency of a 64 x 64 element Lohmann hologram was used to make a mask which, in turn, was used (with conventional photoresist techniques) to produce a holographic reflector. Images from a commercial CO2 laser (150W TEM(00)) and the holographic reflector are illustrated and discussed.

System and method for high power diode based additive manufacturing

DOEpatents

El-Dasher, Bassem S.; Bayramian, Andrew; Demuth, James A.; Farmer, Joseph C.; Torres, Sharon G.

2018-01-02

A system is disclosed for performing an Additive Manufacturing (AM) fabrication process on a powdered material forming a substrate. The system may make use of a diode array for generating an optical signal sufficient to melt a powdered material of the substrate. A mask may be used for preventing a first predetermined portion of the optical signal from reaching the substrate, while allowing a second predetermined portion to reach the substrate. At least one processor may be used for controlling an output of the diode array.

System and method for high power diode based additive manufacturing

DOEpatents

El-Dasher, Bassem S.; Bayramian, Andrew; Demuth, James A.; Farmer, Joseph C.; Torres, Sharon G.

2016-04-12

A system is disclosed for performing an Additive Manufacturing (AM) fabrication process on a powdered material forming a substrate. The system may make use of a diode array for generating an optical signal sufficient to melt a powdered material of the substrate. A mask may be used for preventing a first predetermined portion of the optical signal from reaching the substrate, while allowing a second predetermined portion to reach the substrate. At least one processor may be used for controlling an output of the diode array.

IRACproc: IRAC Post-BCD Processing

NASA Astrophysics Data System (ADS)

Schuster, Mike; Marengo, Massimo; Patten, Brian

2012-09-01

IRACproc is a software suite that facilitates the co-addition of dithered or mapped Spitzer/IRAC data to make them ready for further analysis with application to a wide variety of IRAC observing programs. The software runs within PDL, a numeric extension for Perl available from pdl.perl.org, and as stand alone perl scripts. In acting as a wrapper for the Spitzer Science Center's MOPEX software, IRACproc improves the rejection of cosmic rays and other transients in the co-added data. In addition, IRACproc performs (optional) Point Spread Function (PSF) fitting, subtraction, and masking of saturated stars.

Mask-less patterning of organic light emitting diodes using electrospray and selective biasing on pixel electrodes

NASA Astrophysics Data System (ADS)

Lee, Sangyeob; Koo, Hyun; Cho, Sunghwan

2015-04-01

Wet process of soluble organic light emitting diode (OLED) materials has attracted much attention due to its potential as a large-area manufacturing process with high productivity. Electrospray (ES) deposition is one of candidates of organic thin film formation process for OLED. However, to fabricate red, green, and blue emitters for color display, a fine metal mask is required during spraying emitter materials. We demonstrate a mask-less color pixel patterning process using ES of soluble OLED materials and selective biasing on pixel electrodes and a spray nozzle. We show red and green line patterns of OLED materials. It was found that selective patterning can be allowed by coulomb repulsion between nozzle and pixel. Furthermore, we fabricated blue fluorescent OLED devices by vacuum evaporation and ES processes. The device performance of ES processed OLED showed nearly identical current-voltage characteristics and slightly lower current efficiency compared to vacuum processed OLED.

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.

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

Gratama van Andel, H. A. F.; Venema, H. W.; Streekstra, G. J.

For clear visualization of vessels in CT angiography (CTA) images of the head and neck using maximum intensity projection (MIP) or volume rendering (VR) bone has to be removed. In the past we presented a fully automatic method to mask the bone [matched mask bone elimination (MMBE)] for this purpose. A drawback is that vessels adjacent to bone may be partly masked as well. We propose a modification, multiscale MMBE, which reduces this problem by using images at two scales: a higher resolution than usual for image processing and a lower resolution to which the processed images are transformed formore » use in the diagnostic process. A higher in-plane resolution is obtained by the use of a sharper reconstruction kernel. The out-of-plane resolution is improved by deconvolution or by scanning with narrower collimation. The quality of the mask that is used to remove bone is improved by using images at both scales. After masking, the desired resolution for the normal clinical use of the images is obtained by blurring with Gaussian kernels of appropriate widths. Both methods (multiscale and original) were compared in a phantom study and with clinical CTA data sets. With the multiscale approach the width of the strip of soft tissue adjacent to the bone that is masked can be reduced from 1.0 to 0.2 mm without reducing the quality of the bone removal. The clinical examples show that vessels adjacent to bone are less affected and therefore better visible. Images processed with multiscale MMBE have a slightly higher noise level or slightly reduced resolution compared with images processed by the original method and the reconstruction and processing time is also somewhat increased. Nevertheless, multiscale MMBE offers a way to remove bone automatically from CT angiography images without affecting the integrity of the blood vessels. The overall image quality of MIP or VR images is substantially improved relative to images processed with the original MMBE method.« less

UDOF direct improvement by modulating mask absorber thickness

NASA Astrophysics Data System (ADS)

Yu, Tuan-Yen; Lio, En Chuan; Chen, Po Tsang; Wei, Chih I.; Chen, Yi Ting; Peng, Ming Chun; Chou, William; Yu, Chun Chi

2016-10-01

As the process generation migrate to advanced and smaller dimension or pitch, the mask and resist 3D effects will impact the lithography focus common window severely because of both individual depth-of-focus (iDOF) range decrease and center mismatch. Furthermore, some chemical or thermal factors, such as PEB (Post Exposure Bake) also worsen the usable depth-of-focus (uDOF) performance. So the mismatch of thru-pitch iDOF center should be considered as a lithography process integration issue, and more complicated to partition the 3D effects induced by optical or chemical factors. In order to reduce the impact of 3D effects induced by both optical and chemical issues, and improve iDOF center mismatch, we would like to propose a mask absorber thickness offset approach, which is directly to compensate the iDOF center bias by adjusting mask absorber thickness, for iso, semi-iso or dense characteristics in line, space or via patterns to enlarge common process window, i.e uDOF, which intends to provide similar application as Flexwave[1] (ASML trademark). By the way, since mask absorber thickness offset approach is similar to focus tuning or change on wafer lithography process, it could be acted as the process tuning method of photoresist (PR) profile optimization locally, PR scum improvement in specific patterns or to modulate etching bias to meet process integration request. For mass production consideration, and available material, current att-PSM blank, quartz, MoSi with chrome layer as hard-mask in reticle process, will be implemented in this experiment, i.e. chrome will be kept remaining above partial thru-pitch patterns, and act as the absorber thickness bias in different patterns. And then, from the best focus offset of thru-pitch patterns, the iDOF center shifts could be directly corrected and to enlarge uDOF by increasing the overlap of iDOF. Finally, some negative tone development (NTD) result in line patterns will be demonstrated as well.

How color, regularity, and good Gestalt determine backward masking.

PubMed

Sayim, Bilge; Manassi, Mauro; Herzog, Michael

2014-06-18

The strength of visual backward masking depends on the stimulus onset asynchrony (SOA) between target and mask. Recently, it was shown that the conjoint spatial layout of target and mask is as crucial as SOA. Particularly, masking strength depends on whether target and mask group with each other. The same is true in crowding where the global spatial layout of the flankers and target-flanker grouping determine crowding strength. Here, we presented a vernier target followed by different flanker configurations at varying SOAs. Similar to crowding, masking of a red vernier target was strongly reduced for arrays of 10 green compared with 10 red flanking lines. Unlike crowding, single green lines flanking the red vernier showed strong masking. Irregularly arranged flanking lines yielded stronger masking than did regularly arranged lines, again similar to crowding. While cuboid flankers reduced crowding compared with single lines, this was not the case in masking. We propose that, first, masking is reduced when the flankers are part of a larger spatial structure. Second, spatial factors counteract color differences between the target and the flankers. Third, complex Gestalts, such as cuboids, seem to need longer processing times to show ungrouping effects as observed in crowding. Strong parallels between masking and crowding suggest similar underlying mechanism; however, temporal factors in masking additionally modulate performance, acting as an additional grouping cue. © 2014 ARVO.

[An improved low spectral distortion PCA fusion method].

PubMed

Peng, Shi; Zhang, Ai-Wu; Li, Han-Lun; Hu, Shao-Xing; Meng, Xian-Gang; Sun, Wei-Dong

2013-10-01

Aiming at the spectral distortion produced in PCA fusion process, the present paper proposes an improved low spectral distortion PCA fusion method. This method uses NCUT (normalized cut) image segmentation algorithm to make a complex hyperspectral remote sensing image into multiple sub-images for increasing the separability of samples, which can weaken the spectral distortions of traditional PCA fusion; Pixels similarity weighting matrix and masks were produced by using graph theory and clustering theory. These masks are used to cut the hyperspectral image and high-resolution image into some sub-region objects. All corresponding sub-region objects between the hyperspectral image and high-resolution image are fused by using PCA method, and all sub-regional integration results are spliced together to produce a new image. In the experiment, Hyperion hyperspectral data and Rapid Eye data were used. And the experiment result shows that the proposed method has the same ability to enhance spatial resolution and greater ability to improve spectral fidelity performance.

Mirrors, masks, and motivation: implicit and explicit self-focused attention influence effort-related cardiovascular reactivity.

PubMed

Silvia, Paul J

2012-07-01

Using motivational intensity theory as a framework, three experiments examined how implicit self-focus (manipulated with masked first-name priming) and explicit self-focus (manipulated with a large mirror) influence effort-related cardiovascular activity, particularly systolic blood pressure reactivity. Theories of self-focused attention suggest that both implicit and explicit self-focus bring about self-evaluation and thus make meeting a goal more important. For a "do your best" task of unfixed difficulty, implicit and explicit self-focus both increased effort (Experiment 1) compared to a control condition. For a task that varied in difficulty, implicit and explicit self-focus promoted more effort as the task became increasingly hard (Experiments 2 and 3). Taken together, the findings suggest that implicit and explicit self-processes share a similar motivational architecture. The discussion explores the value of integrating motivational intensity theory with self-awareness theory and considers the emerging interest in implicit aspects of effort regulation. Copyright © 2012 Elsevier B.V. All rights reserved.

Masked Morphological Priming in German-Speaking Adults and Children: Evidence from Response Time Distributions

PubMed Central

Hasenäcker, Jana; Beyersmann, Elisabeth; Schroeder, Sascha

2016-01-01

In this study, we looked at masked morphological priming effects in German children and adults beyond mean response times by taking into account response time distributions. We conducted an experiment comparing suffixed word primes (kleidchen-KLEID), suffixed nonword primes (kleidtum-KLEID), nonsuffixed nonword primes (kleidekt-KLEID), and unrelated controls (träumerei-KLEID). The pattern of priming in adults showed facilitation from suffixed words, suffixed nonwords, and nonsuffixed nonwords relative to unrelated controls, and from both suffixed conditions relative to nonsuffixed nonwords, thus providing evidence for morpho-orthographic and embedded stem priming. Children also showed facilitation from real suffixed words, suffixed nonwords, and nonsuffixed nonwords compared to unrelated words, but no difference between the suffixed and nonsuffixed conditions, thus suggesting that German elementary school children do not make use of morpho-orthographic segmentation. Interestingly, for all priming effects, a shift of the response time distribution was observed. Consequences for theories of morphological processing are discussed. PMID:27445899

Getting the cocktail party started: masking effects in speech perception

PubMed Central

Evans, S; McGettigan, C; Agnew, ZK; Rosen, S; Scott, SK

2016-01-01

Spoken conversations typically take place in noisy environments and different kinds of masking sounds place differing demands on cognitive resources. Previous studies, examining the modulation of neural activity associated with the properties of competing sounds, have shown that additional speech streams engage the superior temporal gyrus. However, the absence of a condition in which target speech was heard without additional masking made it difficult to identify brain networks specific to masking and to ascertain the extent to which competing speech was processed equivalently to target speech. In this study, we scanned young healthy adults with continuous functional Magnetic Resonance Imaging (fMRI), whilst they listened to stories masked by sounds that differed in their similarity to speech. We show that auditory attention and control networks are activated during attentive listening to masked speech in the absence of an overt behavioural task. We demonstrate that competing speech is processed predominantly in the left hemisphere within the same pathway as target speech but is not treated equivalently within that stream, and that individuals who perform better in speech in noise tasks activate the left mid-posterior superior temporal gyrus more. Finally, we identify neural responses associated with the onset of sounds in the auditory environment, activity was found within right lateralised frontal regions consistent with a phasic alerting response. Taken together, these results provide a comprehensive account of the neural processes involved in listening in noise. PMID:26696297

Electrophysiological signals associated with fluency of different levels of processing reveal multiple contributions to recognition memory.

PubMed

Li, Bingbing; Taylor, Jason R; Wang, Wei; Gao, Chuanji; Guo, Chunyan

2017-08-01

Processing fluency appears to influence recognition memory judgements, and the manipulation of fluency, if misattributed to an effect of prior exposure, can result in illusory memory. Although it is well established that fluency induced by masked repetition priming leads to increased familiarity, manipulations of conceptual fluency have produced conflicting results, variously affecting familiarity or recollection. Some recent studies have found that masked conceptual priming increases correct recollection (Taylor & Henson, 2012), and the magnitude of this behavioural effect correlates with analogous fMRI BOLD priming effects in brain regions associated with recollection (Taylor, Buratto, & Henson, 2013). However, the neural correlates and time-courses of masked repetition and conceptual priming were not compared directly in previous studies. The present study used event-related potentials (ERPs) to identify and compare the electrophysiological correlates of masked repetition and conceptual priming and investigate how they contribute to recognition memory. Behavioural results were consistent with previous studies: Repetition primes increased familiarity, whereas conceptual primes increased correct recollection. Masked repetition and conceptual priming also decreased the latency of late parietal component (LPC). Masked repetition priming was associated with an early P200 effect and a later parietal maximum N400 effect, whereas masked conceptual priming was only associated with a central-parietal maximum N400 effect. In addition, the topographic distributions of the N400 repetition priming and conceptual priming effects were different. These results suggest that fluency at different levels of processing is associated with different ERP components, and contributes differentially to subjective recognition memory experiences. Copyright © 2017 Elsevier Inc. All rights reserved.

Spatial Release From Masking in Simulated Cochlear Implant Users With and Without Access to Low-Frequency Acoustic Hearing

PubMed Central

Dietz, Mathias; Hohmann, Volker; Jürgens, Tim

2015-01-01

For normal-hearing listeners, speech intelligibility improves if speech and noise are spatially separated. While this spatial release from masking has already been quantified in normal-hearing listeners in many studies, it is less clear how spatial release from masking changes in cochlear implant listeners with and without access to low-frequency acoustic hearing. Spatial release from masking depends on differences in access to speech cues due to hearing status and hearing device. To investigate the influence of these factors on speech intelligibility, the present study measured speech reception thresholds in spatially separated speech and noise for 10 different listener types. A vocoder was used to simulate cochlear implant processing and low-frequency filtering was used to simulate residual low-frequency hearing. These forms of processing were combined to simulate cochlear implant listening, listening based on low-frequency residual hearing, and combinations thereof. Simulated cochlear implant users with additional low-frequency acoustic hearing showed better speech intelligibility in noise than simulated cochlear implant users without acoustic hearing and had access to more spatial speech cues (e.g., higher binaural squelch). Cochlear implant listener types showed higher spatial release from masking with bilateral access to low-frequency acoustic hearing than without. A binaural speech intelligibility model with normal binaural processing showed overall good agreement with measured speech reception thresholds, spatial release from masking, and spatial speech cues. This indicates that differences in speech cues available to listener types are sufficient to explain the changes of spatial release from masking across these simulated listener types. PMID:26721918

Comparison of experiments and computations for cold gas spraying through a mask. Part 2

NASA Astrophysics Data System (ADS)

Klinkov, S. V.; Kosarev, V. F.; Ryashin, N. S.

2017-03-01

This paper presents experimental and simulation results of cold spray coating deposition using the mask placed above the plane substrate at different distances. Velocities of aluminum (mean size 30 μm) and copper (mean size 60 μm) particles in the vicinity of the mask are determined. It was found that particle velocities have angular distribution in flow with a representative standard deviation of 1.5-2 degrees. Modeling of coating formation behind the mask with account for this distribution was developed. The results of model agree with experimental data confirming the importance of particle angular distribution for coating deposition process in the masked area.

CA resist with high sensitivity and sub-100-nm resolution for advanced mask making

NASA Astrophysics Data System (ADS)

Huang, Wu-Song; Kwong, Ranee W.; Hartley, John G.; Moreau, Wayne M.; Angelopoulos, Marie; Magg, Christopher; Lawliss, Mark

2000-07-01

Recently, there is significant interest in using CA resist for electron beam (E-beam) applications including mask making, direct write, and projection printing. CA resists provide superior lithographic performance in comparison to traditional non-CA E-beam resist in particular high contrast, resolution, and sensitivity. However, most of the commercially available CA resist have the concern of airborne base contaminants and sensitivity to PAB and/or PEB temperatures. In this presentation, we will discuss a new improved ketal resists system referred to as KRS-XE which exhibits excellent lithography, is robust toward airborne base, compatible with 0.263N TMAH aqueous developer and exhibits excellent lithography, is robust toward airborne base, compatible with 0.263N TMAH aqueous developer and exhibits a large PAB/PEB latitude. With the combination of a high performance mask making E-beam exposure tool, high kV shaped beam system EL4+ and the KRS-XE resist, we have printed 75nm lines/space feature with excellent profile control at a dose of 13(mu) C/cm2 at 75kV. The shaped beam vector scan system used here provides a unique property in resolving small features in lithography and throughput. Overhead in EL4+$ limits the systems ability to fully exploit the sensitivity of the new resist for throughput. The EL5 system has sufficiently low overhead that it is projected to print a 4X, 16G DRAM mask with OPC in under 3 hours with the CA resist. We will discuss the throughput advantages of the next generation EL5 system over the existing EL4+.

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.

Is masked priming modulated by memory load? A test of the automaticity of masked identity priming in lexical decision.

PubMed

Perea, Manuel; Marcet, Ana; Lozano, Mario; Gomez, Pablo

2018-05-29

One of the key assumptions of the masked priming lexical decision task (LDT) is that primes are processed without requiring attentional resources. Here, we tested this assumption by presenting a dual-task manipulation to increase memory load and measure the change in masked identity priming on the targets in the LDT. If masked priming does not require attentional resources, increased memory load should have no influence on the magnitude of the observed identity priming effects. We conducted two LDT experiments, using a within-subjects design, to investigate the effect of memory load (via a concurrent matching task Experiment 1 and a concurrent search task in Experiment 2) on masked identity priming. Results showed that the magnitude of masked identity priming on word targets was remarkably similar under high and low memory load. Thus, these experiments provide empirical evidence for the automaticity assumption of masked identity priming in the LDT.

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.

Suppression and Contrast Normalization in Motion Processing

PubMed Central

2017-01-01

Sensory neurons are activated by a range of stimuli to which they are said to be tuned. Usually, they are also suppressed by another set of stimuli that have little effect when presented in isolation. The interactions between preferred and suppressive stimuli are often quite complex and vary across neurons, even within a single area, making it difficult to infer their collective effect on behavioral responses mediated by activity across populations of neurons. Here, we investigated this issue by measuring, in human subjects (three males), the suppressive effect of static masks on the ocular following responses induced by moving stimuli. We found a wide range of effects, which depend in a nonlinear and nonseparable manner on the spatial frequency, contrast, and spatial location of both stimulus and mask. Under some conditions, the presence of the mask can be seen as scaling the contrast of the driving stimulus. Under other conditions, the effect is more complex, involving also a direct scaling of the behavioral response. All of this complexity at the behavioral level can be captured by a simple model in which stimulus and mask interact nonlinearly at two stages, one monocular and one binocular. The nature of the interactions is compatible with those observed at the level of single neurons in primates, usually broadly described as divisive normalization, without having to invoke any scaling mechanism. SIGNIFICANCE STATEMENT The response of sensory neurons to their preferred stimulus is often modulated by stimuli that are not effective when presented alone. Individual neurons can exhibit multiple modulatory effects, with considerable variability across neurons even in a single area. Such diversity has made it difficult to infer the impact of these modulatory mechanisms on behavioral responses. Here, we report the effects of a stationary mask on the reflexive eye movements induced by a moving stimulus. A model with two stages, each incorporating a divisive modulatory mechanism, reproduces our experimental results and suggests that qualitative variability of masking effects in cortical neurons might arise from differences in the extent to which such effects are inherited from earlier stages. PMID:29018158

Near real-time shadow detection and removal in aerial motion imagery application

NASA Astrophysics Data System (ADS)

Silva, Guilherme F.; Carneiro, Grace B.; Doth, Ricardo; Amaral, Leonardo A.; Azevedo, Dario F. G. de

2018-06-01

This work presents a method to automatically detect and remove shadows in urban aerial images and its application in an aerospace remote monitoring system requiring near real-time processing. Our detection method generates shadow masks and is accelerated by GPU programming. To obtain the shadow masks, we converted images from RGB to CIELCh model, calculated a modified Specthem ratio, and applied multilevel thresholding. Morphological operations were used to reduce shadow mask noise. The shadow masks are used in the process of removing shadows from the original images using the illumination ratio of the shadow/non-shadow regions. We obtained shadow detection accuracy of around 93% and shadow removal results comparable to the state-of-the-art while maintaining execution time under real-time constraints.

Variability-aware double-patterning layout optimization for analog circuits

NASA Astrophysics Data System (ADS)

Li, Yongfu; Perez, Valerio; Tripathi, Vikas; Lee, Zhao Chuan; Tseng, I.-Lun; Ong, Jonathan Yoong Seang

2018-03-01

The semiconductor industry has adopted multi-patterning techniques to manage the delay in the extreme ultraviolet lithography technology. During the design process of double-patterning lithography layout masks, two polygons are assigned to different masks if their spacing is less than the minimum printable spacing. With these additional design constraints, it is very difficult to find experienced layout-design engineers who have a good understanding of the circuit to manually optimize the mask layers in order to minimize color-induced circuit variations. In this work, we investigate the impact of double-patterning lithography on analog circuits and provide quantitative analysis for our designers to select the optimal mask to minimize the circuit's mismatch. To overcome the problem and improve the turn-around time, we proposed our smart "anchoring" placement technique to optimize mask decomposition for analog circuits. We have developed a software prototype that is capable of providing anchoring markers in the layout, allowing industry standard tools to perform automated color decomposition process.

Metacontrast masking and attention do not interact.

PubMed

Agaoglu, Sevda; Breitmeyer, Bruno; Ogmen, Haluk

2016-07-01

Visual masking and attention have been known to control the transfer of information from sensory memory to visual short-term memory. A natural question is whether these processes operate independently or interact. Recent evidence suggests that studies that reported interactions between masking and attention suffered from ceiling and/or floor effects. The objective of the present study was to investigate whether metacontrast masking and attention interact by using an experimental design in which saturation effects are avoided. We asked observers to report the orientation of a target bar randomly selected from a display containing either two or six bars. The mask was a ring that surrounded the target bar. Attentional load was controlled by set-size and masking strength by the stimulus onset asynchrony between the target bar and the mask ring. We investigated interactions between masking and attention by analyzing two different aspects of performance: (i) the mean absolute response errors and (ii) the distribution of signed response errors. Our results show that attention affects observers' performance without interacting with masking. Statistical modeling of response errors suggests that attention and metacontrast masking exert their effects by independently modulating the probability of "guessing" behavior. Implications of our findings for models of attention are discussed.

Digital Images and Human Vision

NASA Technical Reports Server (NTRS)

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

1997-01-01

Processing of digital images destined for visual consumption raises many interesting questions regarding human visual sensitivity. This talk will survey some of these questions, including some that have been answered and some that have not. There will be an emphasis upon visual masking, and a distinction will be drawn between masking due to contrast gain control processes, and due to processes such as hypothesis testing, pattern recognition, and visual search.

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

NASA Astrophysics Data System (ADS)

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

2016-03-01

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

Realities of biomedical product liability suits and the role of junk science: from breast implants to TASER weapons.

PubMed

Kroll, Mark

2012-01-01

In the summer of 2006, manufacturers of a simple respirator mask costing US$1 told the U.S. Congress that Americans would find a shortage of these masks if there was another flu pandemic. The reason for this was that suing the makers of these dust masks became a major business for trial lawyers. By 2006, there had been more than 326,000 lawsuits filed. It has been reported in many cases that the law firms worked with cooperative physicians and contracted with X-ray labs to screen individuals for lung problems. If an individual had an abnormal lung X-ray and claimed that they had used a certain brand of respirator and the manufacturer was still in business and had economic resourcesa lawsuit was filed. Some manufacturers went out of business while others simply stopped making the masks.

Accurate mask-based spatially regularized correlation filter for visual tracking

NASA Astrophysics Data System (ADS)

Gu, Xiaodong; Xu, Xinping

2017-01-01

Recently, discriminative correlation filter (DCF)-based trackers have achieved extremely successful results in many competitions and benchmarks. These methods utilize a periodic assumption of the training samples to efficiently learn a classifier. However, this assumption will produce unwanted boundary effects, which severely degrade the tracking performance. Correlation filters with limited boundaries and spatially regularized DCFs were proposed to reduce boundary effects. However, their methods used the fixed mask or predesigned weights function, respectively, which was unsuitable for large appearance variation. We propose an accurate mask-based spatially regularized correlation filter for visual tracking. Our augmented objective can reduce the boundary effect even in large appearance variation. In our algorithm, the masking matrix is converted into the regularized function that acts on the correlation filter in frequency domain, which makes the algorithm fast convergence. Our online tracking algorithm performs favorably against state-of-the-art trackers on OTB-2015 Benchmark in terms of efficiency, accuracy, and robustness.

Fabrication of Fiber-Optic Tilted Bragg Grating Filter in 40 nm Range with A Single Phase Mask

NASA Technical Reports Server (NTRS)

Grant, Joseph; Wang, Y.; Sharma, A.; Burdine, Robert V. (Technical Monitor)

2002-01-01

Fiber-optic Bragg grating filters are fabricated with a range of Bragg wavelength between 1296 and 1336 nm, using a single phase mask. 30 mW of continuous-wave light at 244 nm is used from a frequency-doubled argon-ion laser having an intracavity etalon. Gratings are fabricated by tilting the photosensitive fiber with respect to the phase mask up to an angle of 15 degrees. The variation of Bragg wavelength with the fiber-tilt is explained with a simple formula. High spatial coherence of 244 nm light makes it possible to displace the fiber as much as 6 mm in front of the phase mask and tilt the fiber by as much as 15 degrees. This results in nearly constant band-width and near 100% reflectively for all gratings throughout the 40 nm range.

Vitreous carbon mask substrate for X-ray lithography

DOEpatents

Aigeldinger, Georg [Livermore, CA; Skala, Dawn M [Fremont, CA; Griffiths, Stewart K [Livermore, CA; Talin, Albert Alec [Livermore, CA; Losey, Matthew W [Livermore, CA; Yang, Chu-Yeu Peter [Dublin, CA

2009-10-27

The present invention is directed to the use of vitreous carbon as a substrate material for providing masks for X-ray lithography. The new substrate also enables a small thickness of the mask absorber used to pattern the resist, and this enables improved mask accuracy. An alternative embodiment comprised the use of vitreous carbon as a LIGA substrate wherein the VC wafer blank is etched in a reactive ion plasma after which an X-ray resist is bonded. This surface treatment provides a surface enabling good adhesion of the X-ray photoresist and subsequent nucleation and adhesion of the electrodeposited metal for LIGA mold-making while the VC substrate practically eliminates secondary radiation effects that lead to delamination of the X-ray resist form the substrate, the loss of isolated resist features, and the formation of a resist layer adjacent to the substrate that is insoluble in the developer.

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)

Patterning of light-extraction nanostructures on sapphire substrates using nanoimprint and ICP etching with different masking materials.

PubMed

Chen, Hao; Zhang, Qi; Chou, Stephen Y

2015-02-27

Sapphire nanopatterning is the key solution to GaN light emitting diode (LED) light extraction. One challenge is to etch deep nanostructures with a vertical sidewall in sapphire. Here, we report a study of the effects of two masking materials (SiO2 and Cr) and different etching recipes (the reaction gas ratio, the reaction pressure and the inductive power) in a chlorine-based (BCl3 and Cl2) inductively coupled plasma (ICP) etching of deep nanopillars in sapphire, and the etching process optimization. The masking materials were patterned by nanoimprinting. We have achieved high aspect ratio sapphire nanopillar arrays with a much steeper sidewall than the previous etching methods. We discover that the SiO2 mask has much slower erosion rate than the Cr mask under the same etching condition, leading to the deep cylinder-shaped nanopillars (122 nm diameter, 200 nm pitch, 170 nm high, flat top, and a vertical sidewall of 80° angle), rather than the pyramid-shaped shallow pillars (200 nm based diameter, 52 nm height, and 42° sidewall) resulted by using Cr mask. The processes developed are scalable to large volume LED manufacturing.

Directional Effects between Rapid Auditory Processing and Phonological Awareness in Children

ERIC Educational Resources Information Center

Johnson, Erin Phinney; Pennington, Bruce F.; Lee, Nancy Raitano; Boada, Richard

2009-01-01

Background: Deficient rapid auditory processing (RAP) has been associated with early language impairment and dyslexia. Using an auditory masking paradigm, children with language disabilities perform selectively worse than controls at detecting a tone in a backward masking (BM) condition (tone followed by white noise) compared to a forward masking…

Resist heating effect on e-beam mask writing at 75 kV and 60 A/cm2

NASA Astrophysics Data System (ADS)

Benes, Zdenek; Deverich, Christina; Huang, Chester; Lawliss, Mark

2003-12-01

Resist heating has been known to be one of the main contributors to local CD variation in mask patterning using variable shape e-beam tools. Increasingly complex mask patterns require increased number of shapes which drives the need for higher electron beam current densities to maintain reasonable write times. As beam current density is increased, CD error resulting from resist heating may become a dominating contributor to local CD variations. In this experimental study, the IBM EL4+ mask writer with high voltage and high current density has been used to quantitatively investigate the effect of resist heating on the local CD uniformity. ZEP 7000 and several chemically amplified resists have been evaluated under various exposure conditions (single-pass, multi-pass, variable spot size) and pattern densities. Patterns were designed specifically to allow easy measurement of local CD variations with write strategies designed to maximize the effect of resist heating. Local CD variations as high as 15 nm in 18.75 × 18.75 μm sub-field size have been observed for ZEP 7000 in a single-pass writing with full 1000 nm spots at 50% pattern density. This number can be reduced by increasing the number of passes or by decreasing the maximum spot size. The local CD variation has been reduced to as low as 2 nm for ZEP 7000 for the same pattern under modified exposure conditions. The effectiveness of various writing strategies is discussed as well as their possible deficiencies. Minimal or no resist heating effects have been observed for the chemically amplified resists studied. The results suggest that the resist heating effect can be well controlled by careful selection of the resist/process system and/or writing strategy and that resist heating does not have to pose a problem for high throughput e-beam mask making that requires high voltage and high current densities.

Classification and printability of EUV mask defects from SEM images

NASA Astrophysics Data System (ADS)

Cho, Wonil; Price, Daniel; Morgan, Paul A.; Rost, Daniel; Satake, Masaki; Tolani, Vikram L.

2017-10-01

Classification and Printability of EUV Mask Defects from SEM images EUV lithography is starting to show more promise for patterning some critical layers at 5nm technology node and beyond. However, there still are many key technical obstacles to overcome before bringing EUV Lithography into high volume manufacturing (HVM). One of the greatest obstacles is manufacturing defect-free masks. For pattern defect inspections in the mask-shop, cutting-edge 193nm optical inspection tools have been used so far due to lacking any e-beam mask inspection (EBMI) or EUV actinic pattern inspection (API) tools. The main issue with current 193nm inspection tools is the limited resolution for mask dimensions targeted for EUV patterning. The theoretical resolution limit for 193nm mask inspection tools is about 60nm HP on masks, which means that main feature sizes on EUV masks will be well beyond the practical resolution of 193nm inspection tools. Nevertheless, 193nm inspection tools with various illumination conditions that maximize defect sensitivity and/or main-pattern modulation are being explored for initial EUV defect detection. Due to the generally low signal-to-noise in the 193nm inspection imaging at EUV patterning dimensions, these inspections often result in hundreds and thousands of defects which then need to be accurately reviewed and dispositioned. Manually reviewing each defect is difficult due to poor resolution. In addition, the lack of a reliable aerial dispositioning system makes it very challenging to disposition for printability. In this paper, we present the use of SEM images of EUV masks for higher resolution review and disposition of defects. In this approach, most of the defects detected by the 193nm inspection tools are first imaged on a mask SEM tool. These images together with the corresponding post-OPC design clips are provided to KLA-Tencor's Reticle Decision Center (RDC) platform which provides ADC (Automated Defect Classification) and S2A (SEM-to-Aerial printability) analysis of every defect. First, a defect-free or reference mask SEM is rendered from the post-OPC design, and the defective signature is detected from the defect-reference difference image. These signatures help assess the true nature of the defect as evident in e-beam imaging; for example, excess or missing absorber, line-edge roughness, contamination, etc. Next, defect and reference contours are extracted from the grayscale SEM images and fed into the simulation engine with an EUV scanner model to generate corresponding EUV defect and reference aerial images. These are then analyzed for printability and dispositioned using an Aerial Image Analyzer (AIA) application to automatically measure and determine the amount of CD errors. Thus by integrating EUV ADC and S2A applications together, every defect detection is characterized for its type and printability which is essential for not only determining which defects to repair, but also in monitoring the performance of EUV mask process tools. The accuracy of the S2A print modeling has been verified with other commercially-available simulators, and will also be verified with actual wafer print results. With EUV lithography progressing towards volume manufacturing at 5nm technology, and the likelihood of EBMI inspectors approaching the horizon, the EUV ADC-S2A system will continue serving an essential role of dispositioning defects off e-beam imaging.

Automaticity of higher cognitive functions: neurophysiological evidence for unconscious syntactic processing of masked words.

PubMed

Jiménez-Ortega, Laura; García-Milla, Marcos; Fondevila, Sabela; Casado, Pilar; Hernández-Gutiérrez, David; Martín-Loeches, Manuel

2014-12-01

Models of language comprehension assume that syntactic processing is automatic, at least at early stages. However, the degree of automaticity of syntactic processing is still controversial. Evidence of automaticity is either indirect or has been observed for pairs of words, which might provide a poor syntactic context in comparison to sentences. The present study investigates the automaticity of syntactic processing using event-related brain potentials (ERPs) during sentence processing. To this end, masked adjectives that could either be syntactically correct or incorrect relative to a sentence being processed appeared just prior to the presentation of supraliminal adjectives. The latter could also be correct or incorrect. According to our data, subliminal gender agreement violations embedded in a sentence trigger an early anterior negativity-like modulation, whereas supraliminal gender agreement violations elicited a later anterior negativity. First-pass syntactic parsing thus appears to be unconsciously and automatically elicited. Interestingly, a P600-like modulation of short duration and early latency could also be observed for masked violations. In addition, masked violations also modulated the P600 component elicited by unmasked targets, probably reflecting that the mechanisms of revising a structural mismatch appear affected by subliminal information. According to our findings, both conscious and unconscious processes apparently contribute to syntactic processing. These results are discussed in line with most recent theories of automaticity and syntactic processing. Copyright © 2014 Elsevier B.V. All rights reserved.

Affect of the unconscious: visually suppressed angry faces modulate our decisions.

PubMed

Almeida, Jorge; Pajtas, Petra E; Mahon, Bradford Z; Nakayama, Ken; Caramazza, Alfonso

2013-03-01

Emotional and affective processing imposes itself over cognitive processes and modulates our perception of the surrounding environment. In two experiments, we addressed the issue of whether nonconscious processing of affect can take place even under deep states of unawareness, such as those induced by interocular suppression techniques, and can elicit an affective response that can influence our understanding of the surrounding environment. In Experiment 1, participants judged the likeability of an unfamiliar item--a Chinese character--that was preceded by a face expressing a particular emotion (either happy or angry). The face was rendered invisible through an interocular suppression technique (continuous flash suppression; CFS). In Experiment 2, backward masking (BM), a less robust masking technique, was used to render the facial expressions invisible. We found that despite equivalent phenomenological suppression of the visual primes under CFS and BM, different patterns of affective processing were obtained with the two masking techniques. Under BM, nonconscious affective priming was obtained for both happy and angry invisible facial expressions. However, under CFS, nonconscious affective priming was obtained only for angry facial expressions. We discuss an interpretation of this dissociation between affective processing and visual masking techniques in terms of distinct routes from the retina to the amygdala.

Accurate GM atrophy quantification in MS using lesion-filling with co-registered 2D lesion masks☆

PubMed Central

Popescu, V.; Ran, N.C.G.; Barkhof, F.; Chard, D.T.; Wheeler-Kingshott, C.A.; Vrenken, H.

2014-01-01

Background In multiple sclerosis (MS), brain atrophy quantification is affected by white matter lesions. LEAP and FSL-lesion_filling, replace lesion voxels with white matter intensities; however, they require precise lesion identification on 3DT1-images. Aim To determine whether 2DT2 lesion masks co-registered to 3DT1 images, yield grey and white matter volumes comparable to precise lesion masks. Methods 2DT2 lesion masks were linearly co-registered to 20 3DT1-images of MS patients, with nearest-neighbor (NNI), and tri-linear interpolation. As gold-standard, lesion masks were manually outlined on 3DT1-images. LEAP and FSL-lesion_filling were applied with each lesion mask. Grey (GM) and white matter (WM) volumes were quantified with FSL-FAST, and deep gray matter (DGM) volumes using FSL-FIRST. Volumes were compared between lesion mask types using paired Wilcoxon tests. Results Lesion-filling with gold-standard lesion masks compared to native images reduced GM overestimation by 1.93 mL (p < .001) for LEAP, and 1.21 mL (p = .002) for FSL-lesion_filling. Similar effects were achieved with NNI lesion masks from 2DT2. Global WM underestimation was not significantly influenced. GM and WM volumes from NNI, did not differ significantly from gold-standard. GM segmentation differed between lesion masks in the lesion area, and also elsewhere. Using the gold-standard, FSL-FAST quantified as GM on average 0.4% of the lesion area with LEAP and 24.5% with FSL-lesion_filling. Lesion-filling did not influence DGM volumes from FSL-FIRST. Discussion These results demonstrate that for global GM volumetry, precise lesion masks on 3DT1 images can be replaced by co-registered 2DT2 lesion masks. This makes lesion-filling a feasible method for GM atrophy measurements in MS. PMID:24567908

Spin-on metal oxide materials for N7 and beyond patterning applications

NASA Astrophysics Data System (ADS)

Mannaert, G.; Altamirano-Sanchez, E.; Hopf, T.; Sebaai, F.; Lorant, C.; Petermann, C.; Hong, S.-E.; Mullen, S.; Wolfer, E.; Mckenzie, D.; Yao, H.; Rahman, D.; Cho, J.-Y.; Padmanaban, M.; Piumi, D.

2017-04-01

There is a growing interest in new spin on metal oxide hard mask materials for advanced patterning solutions both in BEOL and FEOL processing. Understanding how these materials respond to plasma conditions may create a competitive advantage. In this study patterning development was done for two challenging FEOL applications where the traditional Si based films were replaced by EMD spin on metal oxides, which acted as highly selective hard masks. The biggest advantage of metal oxide hard masks for advanced patterning lays in the process window improvement at lower or similar cost compared to other existing solutions.

Recognizing speech under a processing load: dissociating energetic from informational factors.

PubMed

Mattys, Sven L; Brooks, Joanna; Cooke, Martin

2009-11-01

Effects of perceptual and cognitive loads on spoken-word recognition have so far largely escaped investigation. This study lays the foundations of a psycholinguistic approach to speech recognition in adverse conditions that draws upon the distinction between energetic masking, i.e., listening environments leading to signal degradation, and informational masking, i.e., listening environments leading to depletion of higher-order, domain-general processing resources, independent of signal degradation. We show that severe energetic masking, such as that produced by background speech or noise, curtails reliance on lexical-semantic knowledge and increases relative reliance on salient acoustic detail. In contrast, informational masking, induced by a resource-depleting competing task (divided attention or a memory load), results in the opposite pattern. Based on this clear dissociation, we propose a model of speech recognition that addresses not only the mapping between sensory input and lexical representations, as traditionally advocated, but also the way in which this mapping interfaces with general cognition and non-linguistic processes.

Contribution of Binaural Masking Release to Improved Speech Intelligibility for different Masker types.

PubMed

Sutojo, Sarinah; van de Par, Steven; Schoenmaker, Esther

2018-06-01

In situations with competing talkers or in the presence of masking noise, speech intelligibility can be improved by spatially separating the target speaker from the interferers. This advantage is generally referred to as spatial release from masking (SRM) and different mechanisms have been suggested to explain it. One proposed mechanism to benefit from spatial cues is the binaural masking release, which is purely stimulus driven. According to this mechanism, the spatial benefit results from differences in the binaural cues of target and masker, which need to appear simultaneously in time and frequency to improve the signal detection. In an alternative proposed mechanism, the differences in the interaural cues improve the segregation of auditory streams, a process, which involves top-down processing rather than being purely stimulus driven. Other than the cues that produce binaural masking release, the interaural cue differences between target and interferer required to improve stream segregation do not have to appear simultaneously in time and frequency. This study is concerned with the contribution of binaural masking release to SRM for three masker types that differ with respect to the amount of energetic masking they exert. Speech intelligibility was measured, employing a stimulus manipulation that inhibits binaural masking release, and analyzed with a metric to account for the number of better-ear glimpses. Results indicate that the contribution of the stimulus-driven binaural masking release plays a minor role while binaural stream segregation and the availability of glimpses in the better ear had a stronger influence on improving the speech intelligibility. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Hot melt extrusion of ion-exchange resin for taste masking.

PubMed

Tan, David Cheng Thiam; Ong, Jeremy Jianming; Gokhale, Rajeev; Heng, Paul Wan Sia

2018-05-30

Taste masking is important for some unpleasant tasting bioactives in oral dosage forms. Among many methods available for taste-masking, use of ion-exchange resin (IER) holds promise. IER combined with hot melt extrusion (HME) may offer additional advantages over solvent methods. IER provides taste masking by complexing with the drug ions and preventing drug dissolution in the mouth. Drug-IER complexation approaches described in literatures are mainly based either on batch processing or column eluting. These methods of drug-IER complexation have obvious limitations such as high solvent volume requirements, multiprocessing steps and extended processing time. Thus, the objective of this study was to develop a single-step, solvent-free, continuous HME process for complexation of drug-IER. The screening study evaluated drug to IER ratio, types of IER and drug complexation methods. In the screening study, a potassium salt of a weakly acidic carboxylate-based cationic IER was found suitable for the HME method. Thereafter, optimization study was conducted by varying HME process parameters such as screw speed, extrusion temperature and drug to IER ratio. It was observed that extrusion temperature and drug to IER ratio are imperative in drug-IER complexation through HME. In summary, this study has established the feasibility of a continuous complexation method for drug to IER using HME for taste masking. Copyright © 2018 Elsevier B.V. All rights reserved.

CDO budgeting

NASA Astrophysics Data System (ADS)

Nesladek, Pavel; Wiswesser, Andreas; Sass, Björn; Mauermann, Sebastian

2008-04-01

The Critical dimension off-target (CDO) is a key parameter for mask house customer, affecting directly the performance of the mask. The CDO is the difference between the feature size target and the measured feature size. The change of CD during the process is either compensated within the process or by data correction. These compensation methods are commonly called process bias and data bias, respectively. The difference between data bias and process bias in manufacturing results in systematic CDO error, however, this systematic error does not take into account the instability of the process bias. This instability is a result of minor variations - instabilities of manufacturing processes and changes in materials and/or logistics. Using several masks the CDO of the manufacturing line can be estimated. For systematic investigation of the unit process contribution to CDO and analysis of the factors influencing the CDO contributors, a solid understanding of each unit process and huge number of masks is necessary. Rough identification of contributing processes and splitting of the final CDO variation between processes can be done with approx. 50 masks with identical design, material and process. Such amount of data allows us to identify the main contributors and estimate the effect of them by means of Analysis of variance (ANOVA) combined with multivariate analysis. The analysis does not provide information about the root cause of the variation within the particular unit process, however, it provides a good estimate of the impact of the process on the stability of the manufacturing line. Additionally this analysis can be used to identify possible interaction between processes, which cannot be investigated if only single processes are considered. Goal of this work is to evaluate limits for CDO budgeting models given by the precision and the number of measurements as well as partitioning the variation within the manufacturing process. The CDO variation splits according to the suggested model into contributions from particular processes or process groups. Last but not least the power of this method to determine the absolute strength of each parameter will be demonstrated. Identification of the root cause of this variation within the unit process itself is not scope of this work.

Modular multiaperatures for light sensors

NASA Technical Reports Server (NTRS)

Rizzo, A. A.

1977-01-01

Process involves electroplating multiaperature masks as unit, eliminating alinement and assembly difficulties previously encountered. Technique may be applied to masks in automated and surveillance light systems, when precise, wide angle field of view is needed.

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)

Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind braille readers.

PubMed

Bhattacharjee, Arindam; Ye, Amanda J; Lisak, Joy A; Vargas, Maria G; Goldreich, Daniel

2010-10-27

Braille reading is a demanding task that requires the identification of rapidly varying tactile patterns. During proficient reading, neighboring characters impact the fingertip at ∼100 ms intervals, and adjacent raised dots within a character at 50 ms intervals. Because the brain requires time to interpret afferent sensorineural activity, among other reasons, tactile stimuli separated by such short temporal intervals pose a challenge to perception. How, then, do proficient Braille readers successfully interpret inputs arising from their fingertips at such rapid rates? We hypothesized that somatosensory perceptual consolidation occurs more rapidly in proficient Braille readers. If so, Braille readers should outperform sighted participants on masking tasks, which demand rapid perceptual processing, but would not necessarily outperform the sighted on tests of simple vibrotactile sensitivity. To investigate, we conducted two-interval forced-choice vibrotactile detection, amplitude discrimination, and masking tasks on the index fingertips of 89 sighted and 57 profoundly blind humans. Sighted and blind participants had similar unmasked detection (25 ms target tap) and amplitude discrimination (compared with 100 μm reference tap) thresholds, but congenitally blind Braille readers, the fastest readers among the blind participants, exhibited significantly less masking than the sighted (masker, 50 Hz, 50 μm; target-masker delays, ±50 and ±100 ms). Indeed, Braille reading speed correlated significantly and specifically with masking task performance, and in particular with the backward masking decay time constant. We conclude that vibrotactile sensitivity is unchanged but that perceptual processing is accelerated in congenitally blind Braille readers.

Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind Braille readers

PubMed Central

Bhattacharjee, Arindam; Ye, Amanda J.; Lisak, Joy A.; Vargas, Maria G.; Goldreich, Daniel

2010-01-01

Braille reading is a demanding task that requires the identification of rapidly varying tactile patterns. During proficient reading, neighboring characters impact the fingertip at about 100-ms intervals, and adjacent raised dots within a character at 50-ms intervals. Because the brain requires time to interpret afferent sensorineural activity, among other reasons, tactile stimuli separated by such short temporal intervals pose a challenge to perception. How, then, do proficient Braille readers successfully interpret inputs arising from their fingertips at such rapid rates? We hypothesized that somatosensory perceptual consolidation occurs more rapidly in proficient Braille readers. If so, Braille readers should outperform sighted participants on masking tasks, which demand rapid perceptual processing, but would not necessarily outperform the sighted on tests of simple vibrotactile sensitivity. To investigate, we conducted two-interval forced-choice vibrotactile detection, amplitude discrimination, and masking tasks on the index fingertips of 89 sighted and 57 profoundly blind humans. Sighted and blind participants had similar unmasked detection (25-ms target tap) and amplitude discrimination (compared to 100-micron reference tap) thresholds, but congenitally blind Braille readers, the fastest readers among the blind participants, exhibited significantly less masking than the sighted (masker: 50-Hz, 50-micron; target-masker delays ±50 and ±100 ms). Indeed, Braille reading speed correlated significantly and specifically with masking task performance, and in particular with the backward masking decay time constant. We conclude that vibrotactile sensitivity is unchanged, but that perceptual processing is accelerated in congenitally blind Braille readers. PMID:20980584

High performance, inexpensive solar cell process capable of a high degree of automation

NASA Technical Reports Server (NTRS)

Shah, P.; Fuller, C. R.

1976-01-01

This paper proposes a process for inexpensive high performance solar cell fabrication that can be automated for further cost reduction and higher throughputs. The unique feature of the process is the use of oxides as doping sources for simultaneous n(+) junction formation and back p(+) layer, as a mask for metallization and as an in situ AR coating for spectrum matching. Cost analysis is performed to show that significant cost reductions over the conventional process is possible using the proposed scheme and the cost intensive steps are identified which can be further reduced to make the process compatible with the needed price goals of 50 cents/watt. The process was demonstrated by fabricating n(+)-p cells using Arsenic doped oxides. Simple n(+)-p structure cells showed corrected efficiencies of 14.5% (AMO) and 12% with doped oxide as an in situ antireflection coating.

Acoustically Enhanced Electroplating Being Developed

NASA Technical Reports Server (NTRS)

Oeftering, Richard C.

2002-01-01

In cooperation with the NASA Glenn Research Center, Alchemitron Corp. is developing the Acoustically Enhanced Electroplating Process (AEEP), a new technique of employing nonlinear ultrasonics to enhance electroplating. The applications range from electroplating full-panel electronic circuit boards to electroplating microelectronics and microelectromechanical systems (MEMS) devices. In a conventional plating process, the surface area to be plated is separated from the nonplated areas by a temporary mask. The mask may take many forms, from a cured liquid coating to a simple tape. Generally, the mask is discarded when the plating is complete, creating a solid waste product that is often an environmental hazard. The labor and materials involved with the layout, fabrication, and tooling of masks is a primary source of recurring and nonrecurring production costs. The objective of this joint effort, therefore, is to reduce or eliminate the need for masks. AEEP improves selective plating processes by using directed beams of high-intensity acoustic waves to create nonlinear effects that alter the fluid dynamic and thermodynamic behavior of the plating process. It relies on two effects: acoustic streaming and acoustic heating. Acoustic streaming is observed when a high-intensity acoustic beam creates a liquid current within the beam. The liquid current can be directed as the beam is directed and, thus, users can move liquid around as desired without using pumps and nozzles. The current of the electroplating electrolyte, therefore, can be directed at distinct target areas where electroplating is desired. The current delivers fresh electrolyte to the target area while flushing away the spent electrolyte. This dramatically increases the plating rate in the target area. In addition, acoustic heating of both the liquid in the beam and the target surface increases the chemical reaction rate, which further increases the plating rate. The combined effects of acoustic streaming and heating accelerate the deposition of plating in that area and, thus, provide an effect similar to a mask but without the costs of masking. AEEP further improves the plating process by clearing debris and bubbles from the surface by acoustic radiation pressure and acoustic streaming.

Spirit of the Colleges, Voice of the People Students Share Pain, Hope Through Art

ERIC Educational Resources Information Center

Robbins, Rebecca L.

2005-01-01

Tribal colleges and universities, in addition to providing our people with higher education, help to bridge the gap among cultures. The colleges sustain American Indian art forms through class and degree offerings that include traditional (shield making, drum making, arrow making, knapping, carving, masks, and pottery), contemporary (digital art,…

Temporal mapping and analysis

NASA Technical Reports Server (NTRS)

O'Hara, Charles G. (Inventor); Shrestha, Bijay (Inventor); Vijayaraj, Veeraraghavan (Inventor); Mali, Preeti (Inventor)

2011-01-01

A compositing process for selecting spatial data collected over a period of time, creating temporal data cubes from the spatial data, and processing and/or analyzing the data using temporal mapping algebra functions. In some embodiments, the temporal data cube is creating a masked cube using the data cubes, and computing a composite from the masked cube by using temporal mapping algebra.

Suppression of Mirror Generalization for Reversible Letters: Evidence from Masked Priming

ERIC Educational Resources Information Center

Perea, Manuel; Moret-Tatay, Carmen; Panadero, Victoria

2011-01-01

Readers of the Roman script must "unlearn" some forms of mirror generalization when processing printed stimuli (i.e., herb and herd are different words). Here we examine whether the suppression of mirror generalization is a process that affects all letters or whether it mostly affects reversible letters (i.e., b/d). Three masked priming lexical…

Nanofabrication on unconventional substrates using transferred hard masks

DOE PAGES

Li, Luozhou; Bayn, Igal; Lu, Ming; ...

2015-01-15

Here, a major challenge in nanofabrication is to pattern unconventional substrates that cannot be processed for a variety of reasons, such as incompatibility with spin coating, electron beam lithography, optical lithography, or wet chemical steps. Here, we present a versatile nanofabrication method based on re-usable silicon membrane hard masks, patterned using standard lithography and mature silicon processing technology. These masks, transferred precisely onto targeted regions, can be in the millimetre scale. They allow for fabrication on a wide range of substrates, including rough, soft, and non-conductive materials, enabling feature linewidths down to 10 nm. Plasma etching, lift-off, and ion implantationmore » are realized without the need for scanning electron/ion beam processing, UV exposure, or wet etching on target substrates.« less

Optimization of optical proximity correction to reduce mask write time using genetic algorithm

NASA Astrophysics Data System (ADS)

Dick, Gregory J.; Cao, Liang; Asthana, Abhishek; Cheng, Jing; Power, David N.

2018-03-01

The ever increasing pattern densities and design complexities make the tuning of optical proximity correction (OPC) recipes very challenging. One known method for tuning is genetic algorithm (GA). Previously GA has been demonstrated to fine tune OPC recipes in order to achieve better results for possible 1D and 2D geometric concerns like bridging and pinching. This method, however, did not take into account the impact of excess segmentation on downstream operations like fracturing and mask writing. This paper introduces a general methodology to significantly reduce the number of excess edges in the OPC output, thus reducing the number of flashes generated at fracture and subsequently the write time at mask build. GA is used to reduce the degree of unwarranted segmentation while ensuring good OPC quality. An Objective Function (OF) is utilized to ensure quality convergence and process-variation (PV) plus an additional weighed factor to reduce clustered edge count. The technique is applied to 14nm metal layer OPC recipes in order to identify excess segmentation and to produce a modified recipe that significantly reduces these segments. OPC output file sizes is shown to be reduced by 15% or more and overall edge count is shown to be reduced by 10% or more. At the same time overall quality of the OPC recipe is shown to be maintained via OPC Verification (OPCV) results.

Mask industry assessment: 2008

NASA Astrophysics Data System (ADS)

Hughes, Greg; Yun, Henry

2008-10-01

Microelectronics industry leaders routinely name the cost and cycle time of mask technology and mask supply as top critical issues. A survey was created with support from SEMATECH and administered by David Powell Consulting to gather information about the mask industry as an objective assessment of its overall condition. The survey is designed with the input of semiconductor company mask technologists, merchant mask suppliers, and industry equipment makers. This year's assessment is the seventh 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. The report 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 is basically the same as the 2005 through 2007 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 is a multitude of questions that create a detailed profile of both the business and technical status of the critical mask industry.

Mask industry assessment trend analysis: 2010

NASA Astrophysics Data System (ADS)

Hughes, Greg; Yun, Henry

2010-05-01

Microelectronics industry leaders consistently cite the cost and cycle time of mask technology and mask supply as top critical issues. A survey was designed with input from semiconductor company mask technologists and merchant mask suppliers and support from SEMATECH to gather information about the mask industry as an objective assessment of its overall condition. This year's assessment was the eighth in the current series of annual reports. Its data were presented in detail at BACUS, and the detailed trend analysis is presented at EMLC. With continued 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. The report will continue to serve as a valuable reference to identify the strengths and opportunities of the mask industry. Its results will be used to guide future investments on critical path issues. This year's survey is basically the same as the surveys in 2005 through 2009. 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 creates a detailed profile of both the business and technical status of the critical mask industry.

The 2002 to 2010 mask survey trend analysis

NASA Astrophysics Data System (ADS)

Hughes, Greg; Chan, David

2011-03-01

Microelectronics industry leaders consistently cite the cost and cycle time of mask technology and mask supply as top critical issues. A survey was designed with input from semiconductor company mask technologists and merchant mask suppliers and support from SEMATECH to gather information about the mask industry as an objective assessment of its overall condition. This year's assessment was the ninth in the current series of annual reports. Its data were presented in detail at BACUS, and the detailed trend analysis is presented at EMLC. With continued 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. The report will continue to serve as a valuable reference to identify the strengths and opportunities of the mask industry. Results will be used to guide future investments in critical path issues. This year's survey is basically the same as the 2005 through 2010 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 are multiple questions that ultimately create a detailed profile of both the business and technical status of the critical mask industry.

Rigorous diffraction analysis using geometrical theory of diffraction for future mask technology

NASA Astrophysics Data System (ADS)

Chua, Gek S.; Tay, Cho J.; Quan, Chenggen; Lin, Qunying

2004-05-01

Advanced lithographic techniques such as phase shift masks (PSM) and optical proximity correction (OPC) result in a more complex mask design and technology. In contrast to the binary masks, which have only transparent and nontransparent regions, phase shift masks also take into consideration transparent features with a different optical thickness and a modified phase of the transmitted light. PSM are well-known to show prominent diffraction effects, which cannot be described by the assumption of an infinitely thin mask (Kirchhoff approach) that is used in many commercial photolithography simulators. A correct prediction of sidelobe printability, process windows and linearity of OPC masks require the application of rigorous diffraction theory. The problem of aerial image intensity imbalance through focus with alternating Phase Shift Masks (altPSMs) is performed and compared between a time-domain finite-difference (TDFD) algorithm (TEMPEST) and Geometrical theory of diffraction (GTD). Using GTD, with the solution to the canonical problems, we obtained a relationship between the edge on the mask and the disturbance in image space. The main interest is to develop useful formulations that can be readily applied to solve rigorous diffraction for future mask technology. Analysis of rigorous diffraction effects for altPSMs using GTD approach will be discussed.

Living kidney donation and masked nationalism in Israel.

PubMed

Epstein, Miran

2017-01-01

This paper draws attention to a current trend of masked conditional-nationalist living kidney donation in Israel, to which the local transplant system has been turning a blind eye. The paper seeks to make the international transplant and bioethics communities aware of this disturbing trend. It also explains why it is wrong and suggests how to tackle it. Finally, it calls on the Israeli system to bring the practice to a halt for the benefit of all parties involved.

The relationship between masking and short-term consolidation during recall from visual working memory.

PubMed

Ricker, Timothy J; Sandry, Joshua

2018-04-10

The presentation of a similar but irrelevant stimulus immediately following presentation of a memory item is called masking. Masking is known to reduce performance on working memory tests. This is the type of memory used to hold information in mind for brief periods of time for use in ongoing cognition. Two approaches to understanding masking effects have been proposed in different literatures. Working memory researchers often assume that the reduction in working memory performance after masking is because masking interferes with a transient sensory representation that is needed to complete consolidation into a working memory state. Researchers focused on the attentional blink, a finding that attention cannot be directed to new stimuli during working memory consolidation, have an alternative theory. Attentional blink researchers assume that masking slows the short-term consolidation process, thereby extending the length of the attentional blink. In two experiments, we contrast these two approaches to explaining masking effects and investigate the validity of both hypotheses. Some aspects of both approaches are validated, but neither theoretical perspective alone sufficiently explains the entire pattern of results. © 2018 New York Academy of Sciences.

Advanced EUV mask and imaging modeling

NASA Astrophysics Data System (ADS)

Evanschitzky, Peter; Erdmann, Andreas

2017-10-01

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

The binaural masking level difference: cortical correlates persist despite severe brain stem atrophy in progressive supranuclear palsy

PubMed Central

Rowe, James B.; Ghosh, Boyd C. P.; Carlyon, Robert P.; Plack, Christopher J.; Gockel, Hedwig E.

2014-01-01

Under binaural listening conditions, the detection of target signals within background masking noise is substantially improved when the interaural phase of the target differs from that of the masker. Neural correlates of this binaural masking level difference (BMLD) have been observed in the inferior colliculus and temporal cortex, but it is not known whether degeneration of the inferior colliculus would result in a reduction of the BMLD in humans. We used magnetoencephalography to examine the BMLD in 13 healthy adults and 13 patients with progressive supranuclear palsy (PSP). PSP is associated with severe atrophy of the upper brain stem, including the inferior colliculus, confirmed by voxel-based morphometry of structural MRI. Stimuli comprised in-phase sinusoidal tones presented to both ears at three levels (high, medium, and low) masked by in-phase noise, which rendered the low-level tone inaudible. Critically, the BMLD was measured using a low-level tone presented in opposite phase across ears, making it audible against the noise. The cortical waveforms from bilateral auditory sources revealed significantly larger N1m peaks for the out-of-phase low-level tone compared with the in-phase low-level tone, for both groups, indicating preservation of early cortical correlates of the BMLD in PSP. In PSP a significant delay was observed in the onset of the N1m deflection and the amplitude of the P2m was reduced, but these differences were not restricted to the BMLD condition. The results demonstrate that although PSP causes subtle auditory deficits, binaural processing can survive the presence of significant damage to the upper brain stem. PMID:25231610

The binaural masking level difference: cortical correlates persist despite severe brain stem atrophy in progressive supranuclear palsy.

PubMed

Hughes, Laura E; Rowe, James B; Ghosh, Boyd C P; Carlyon, Robert P; Plack, Christopher J; Gockel, Hedwig E

2014-12-15

Under binaural listening conditions, the detection of target signals within background masking noise is substantially improved when the interaural phase of the target differs from that of the masker. Neural correlates of this binaural masking level difference (BMLD) have been observed in the inferior colliculus and temporal cortex, but it is not known whether degeneration of the inferior colliculus would result in a reduction of the BMLD in humans. We used magnetoencephalography to examine the BMLD in 13 healthy adults and 13 patients with progressive supranuclear palsy (PSP). PSP is associated with severe atrophy of the upper brain stem, including the inferior colliculus, confirmed by voxel-based morphometry of structural MRI. Stimuli comprised in-phase sinusoidal tones presented to both ears at three levels (high, medium, and low) masked by in-phase noise, which rendered the low-level tone inaudible. Critically, the BMLD was measured using a low-level tone presented in opposite phase across ears, making it audible against the noise. The cortical waveforms from bilateral auditory sources revealed significantly larger N1m peaks for the out-of-phase low-level tone compared with the in-phase low-level tone, for both groups, indicating preservation of early cortical correlates of the BMLD in PSP. In PSP a significant delay was observed in the onset of the N1m deflection and the amplitude of the P2m was reduced, but these differences were not restricted to the BMLD condition. The results demonstrate that although PSP causes subtle auditory deficits, binaural processing can survive the presence of significant damage to the upper brain stem. Copyright © 2014 the American Physiological Society.

CA resist with high sensitivity and sub-100-nm resolution for advanced mask and device making

NASA Astrophysics Data System (ADS)

Kwong, Ranee W.; Huang, Wu-Song; Hartley, John G.; Moreau, Wayne M.; Robinson, Christopher F.; Angelopoulos, Marie; Magg, Christopher; Lawliss, Mark

2000-07-01

Recently, there is significant interest in using CA resists for electron beam (E-Beam) applications including mask making, direct write, and projection printing. CA resists provide superior lithographic performance in comparison to traditional non CA E-beam resists in particular high contrast, resolution, and sensitivity. However, most of the commercially available CA resists have the concern of airborne base contaminants and sensitivity to PAB and/or PEB temperatures. In this presentation, we will discuss a new improved ketal resist system referred to as KRS-XE which exhibits excellent lithography, is robust toward airborne base, compatible with 0.263 N TMAH aqueous developer and exhibits a large PAB/PEB latitude. With the combination of a high performance mask making E-beam exposure tool, high kV (75 kV) shaped beam system EL4+ and the KRS-XE resist, we have printed 75 nm lines/space features with excellent profile control at a dose of 13 (mu) C/cm2 at 75 kV. The shaped beam vector scan system used here provides an unique property in resolving small features in lithography and throughput. Overhead in EL4+ limits the systems ability to fully exploit the sensitivity of the new resist for throughput. The EL5 system, currently in the build phase, has sufficiently low overhead that it is projected to print a 4X, 16G, DRAM mask with OPC in under 3 hours with the CA resist. We will discuss the throughput advantages of the next generation EL5 system over the existing EL4+. In addition we will show the resolution of KRS-XE down to 70 nm using the PREVAIL projection printing system.

Utilization of optical emission endpoint in photomask dry etch processing

NASA Astrophysics Data System (ADS)

Faure, Thomas B.; Huynh, Cuc; Lercel, Michael J.; Smith, Adam; Wagner, Thomas

2002-03-01

Use of accurate and repeatable endpoint detection during dry etch processing of photomask is very important for obtaining good mask mean-to-target and CD uniformity performance. It was found that the typical laser reflectivity endpoint detecting system used on photomask dry etch systems had several key limitations that caused unnecessary scrap and non-optimum image size performance. Consequently, work to develop and implement use of a more robust optical emission endpoint detection system for chrome dry etch processing of photomask was performed. Initial feasibility studies showed that the emission technique was sensitive enough to monitor pattern loadings on contact and via level masks down to 3 percent pattern coverage. Additional work was performed to further improve this to 1 percent pattern coverage by optimizing the endpoint detection parameters. Comparison studies of mask mean-to-target performance and CD uniformity were performed with the use of optical emission endpoint versus laser endpoint for masks built using TOK IP3600 and ZEP 7000 resist systems. It was found that an improvement in mean-to-target performance and CD uniformity was realized on several types of production masks. In addition, part-to-part endpoint time repeatability was found to be significantly improved with the use of optical emission endpoint.

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

NASA Astrophysics Data System (ADS)

Hosono, Kunihiro; Kato, Kokoro

2008-10-01

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

Asymmetric multiple information cryptosystem based on chaotic spiral phase mask and random spectrum decomposition

NASA Astrophysics Data System (ADS)

Rafiq Abuturab, Muhammad

2018-01-01

A new asymmetric multiple information cryptosystem based on chaotic spiral phase mask (CSPM) and random spectrum decomposition is put forwarded. In the proposed system, each channel of secret color image is first modulated with a CSPM and then gyrator transformed. The gyrator spectrum is randomly divided into two complex-valued masks. The same procedure is applied to multiple secret images to get their corresponding first and second complex-valued masks. Finally, first and second masks of each channel are independently added to produce first and second complex ciphertexts, respectively. The main feature of the proposed method is the different secret images encrypted by different CSPMs using different parameters as the sensitive decryption/private keys which are completely unknown to unauthorized users. Consequently, the proposed system would be resistant to potential attacks. Moreover, the CSPMs are easier to position in the decoding process owing to their own centering mark on axis focal ring. The retrieved secret images are free from cross-talk noise effects. The decryption process can be implemented by optical experiment. Numerical simulation results demonstrate the viability and security of the proposed method.

The modulatory influence of the functional COMT Val158Met polymorphism on lexical decisions and semantic priming.

PubMed

Reuter, Martin; Montag, Christian; Peters, Kristina; Kocher, Anne; Kiefer, Markus

2009-01-01

The role of the prefrontal Cortex (PFC) in higher cognitive functions - including working memory, conflict resolution, set shifting and semantic processing - has been demonstrated unequivocally. Despite the great heterogeneity among tasks measuring these phenotypes, due in part to the different cognitive sub-processes implied and the specificity of the stimulus material used, there is agreement that all of these tasks recruit an executive control system located in the PFC. On a biochemical level it is known that the dopaminergic system plays an important role in executive control functions. Evidence comes from molecular genetics relating the functional COMT Val158Met polymorphism to working memory and set shifting. In order determine whether this pattern of findings generalises to linguistic and semantic processing, we investigated the effects of the COMT Val158Met polymorphism in lexical decision making using masked and unmasked versions of the semantic priming paradigm on N = 104 healthy subjects. Although we observed strong priming effects in all conditions (masked priming, unmasked priming with short/long stimulus asynchronies (SOAs), direct and indirect priming), COMT was not significantly related to priming, suggesting no reliable influence on semantic processing. However, COMT Val158Met was strongly associated with lexical decision latencies in all priming conditions if considered separately, explaining between 9 and 14.5% of the variance. Therefore, the findings indicate that COMT mainly influences more general executive control functions in the PFC supporting the speed of lexical decisions.

Automated hotspot analysis with aerial image CD metrology for advanced logic devices

NASA Astrophysics Data System (ADS)

Buttgereit, Ute; Trautzsch, Thomas; Kim, Min-ho; Seo, Jung-Uk; Yoon, Young-Keun; Han, Hak-Seung; Chung, Dong Hoon; Jeon, Chan-Uk; Meyers, Gary

2014-09-01

Continuously shrinking designs by further extension of 193nm technology lead to a much higher probability of hotspots especially for the manufacturing of advanced logic devices. The CD of these potential hotspots needs to be precisely controlled and measured on the mask. On top of that, the feature complexity increases due to high OPC load in the logic mask design which is an additional challenge for CD metrology. Therefore the hotspot measurements have been performed on WLCD from ZEISS, which provides the benefit of reduced complexity by measuring the CD in the aerial image and qualifying the printing relevant CD. This is especially of advantage for complex 2D feature measurements. Additionally, the data preparation for CD measurement becomes more critical due to the larger amount of CD measurements and the increasing feature diversity. For the data preparation this means to identify these hotspots and mark them automatically with the correct marker required to make the feature specific CD measurement successful. Currently available methods can address generic pattern but cannot deal with the pattern diversity of the hotspots. The paper will explore a method how to overcome those limitations and to enhance the time-to-result in the marking process dramatically. For the marking process the Synopsys WLCD Output Module was utilized, which is an interface between the CATS mask data prep software and the WLCD metrology tool. It translates the CATS marking directly into an executable WLCD measurement job including CD analysis. The paper will describe the utilized method and flow for the hotspot measurement. Additionally, the achieved results on hotspot measurements utilizing this method will be presented.

Brain-Building Math Games.

ERIC Educational Resources Information Center

Jung, Loretta Welk

1983-01-01

Index cards, masking tape, pizza shells, golf tees, and empty soda bottles can be used to make manipulative objects to be used in children's mathematics games. Twenty-two games that provide practice in number drills and problem solving are described, along with instructions for making objects needed for the games. (PP)

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

NASA Astrophysics Data System (ADS)

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

2011-03-01

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

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

Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation.

PubMed

Tapia, Evelina; Beck, Diane M

2014-01-01

A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness.

3D printed facial laser scans for the production of localised radiotherapy treatment masks - A case study.

PubMed

Briggs, Matthew; Clements, Helen; Wynne, Neil; Rennie, Allan; Kellett, Darren

This study investigates the use of 3D printing for patients that require localised radiotherapy treatment to the face. The current process involves producing a lead mask in order to protect the healthy tissue from the effects of the radiotherapy. The mask is produced by applying a thermoplastic sheet to the patient's face and allowing to set hard. This can then be used as a mould to create a plaster impression of the patient's face. A sheet of lead is then hammered on to the plaster to create a bespoke fitted face mask. This process can be distressing for patients and can be problematic when the patient is required to remain motionless for a prolonged time while the thermoplastic sets. In this study, a 1:1 scale 3D print of a patient's face was generated using a laser scanner. The lead was hammered directly on to the surface of the 3D print in order to create a bespoke fitted treatment mask. This eliminated the thermoplastic moulding stage and significantly reduced the time needed for the patient to be in clinic. The higher definition impression of the the face resulted in a more accurate, better fitting treatment mask.

Metal oxide multilayer hard mask system for 3D nanofabrication

NASA Astrophysics Data System (ADS)

Han, Zhongmei; Salmi, Emma; Vehkamäki, Marko; Leskelä, Markku; Ritala, Mikko

2018-02-01

We demonstrate the preparation and exploitation of multilayer metal oxide hard masks for lithography and 3D nanofabrication. Atomic layer deposition (ALD) and focused ion beam (FIB) technologies are applied for mask deposition and mask patterning, respectively. A combination of ALD and FIB was used and a patterning procedure was developed to avoid the ion beam defects commonly met when using FIB alone for microfabrication. ALD grown Al2O3/Ta2O5/Al2O3 thin film stacks were FIB milled with 30 keV gallium ions and chemically etched in 5% tetramethylammonium hydroxide at 50 °C. With metal evaporation, multilayers consisting of amorphous oxides Al2O3 and Ta2O5 can be tailored for use in 2D lift-off processing, in preparation of embedded sub-100 nm metal lines and for multilevel electrical contacts. Good pattern transfer was achieved by lift-off process from the 2D hard mask for micro- and nano-scaled fabrication. As a demonstration of the applicability of this method to 3D structures, self-supporting 3D Ta2O5 masks were made from a film stack on gold particles. Finally, thin film resistors were fabricated by utilizing controlled stiction of suspended Ta2O5 structures.

Unconscious processing of facial affect in children and adolescents.

PubMed

Killgore, William D S; Yurgelun-Todd, Deborah A

2007-01-01

In a previous study, with adults, we demonstrated that the amygdala and anterior cingulate gyrus are differentially responsive to happy and sad faces presented subliminally. Because the ability to perceive subtle facial signals communicating sadness is an important aspect of prosocial development, and is critical for empathic behavior, we examined this phenomenon from a developmental perspective using a backward masking paradigm. While undergoing functional magnetic resonance imaging (fMRI), 10 healthy adolescent children were presented with a series of happy and sad facial expressions, each lasting 20 ms and masked immediately by a neutral face to prevent conscious awareness of the affective expression. Relative to fixation baseline, masked sad faces activated the right amygdala, whereas masked happy faces failed to activate any of the regions of interest. Direct comparison between masked happy and sad faces revealed valence specific differences in the anterior cingulate gyrus. When the data were compared statistically to our previous sample of adults, the adolescent group showed significantly greater activity in the right amygdala relative to the adults during the masked sad condition. Groups also differed in several non-hypothesized regions. Development of unconscious perception from adolescence into adulthood appears to be accompanied by reduced activity within limbic affect processing systems, and perhaps increased involvement of other cortical and cerebellar systems.

Ambulatory Blood Pressure Monitoring in the Diagnosis and Treatment of Hypertension.

PubMed

Islam, Md Shahidul

2017-01-01

Clinicians should take initiatives to establish ambulatory blood pressure monitoring (ABPM) services in their own practice, or to ensure that they have access to such services elsewhere. Whenever possible, ABPM should be performed in suitable cases, where it is likely to deliver clinically useful information for making a correct diagnosis, or for tailoring the anti-hypertensive treatment regimen for each individual patient. ABPM is clinically useful, among others, for identifying people with "masked normotension", "masked hypertension", "sleep-time hypertension", and "reduced decline of sleep-time blood pressure". This review briefly outlines the rationales for the use of ABPM, interpretations of the ABPM-derived parameters, and the advantages of ABPM in decision making in the management of hypertension.

Reservoir computing with a slowly modulated mask signal for preprocessing using a mutually coupled optoelectronic system

NASA Astrophysics Data System (ADS)

Tezuka, Miwa; Kanno, Kazutaka; Bunsen, Masatoshi

2016-08-01

Reservoir computing is a machine-learning paradigm based on information processing in the human brain. We numerically demonstrate reservoir computing with a slowly modulated mask signal for preprocessing by using a mutually coupled optoelectronic system. The performance of our system is quantitatively evaluated by a chaotic time series prediction task. Our system can produce comparable performance with reservoir computing with a single feedback system and a fast modulated mask signal. We showed that it is possible to slow down the modulation speed of the mask signal by using the mutually coupled system in reservoir computing.

Data-derived symbol synchronization of MASK and QASK signals. [for multilevel digital communication systems

NASA Technical Reports Server (NTRS)

Simon, M. K.

1974-01-01

Multilevel amplitude-shift-keying (MASK) and quadrature amplitude-shift-keying (QASK) as signaling techniques for multilevel digital communications systems, and the problem of providing symbol synchronization in the receivers of such systems are discussed. A technique is presented for extracting symbol sync from an MASK or QASK signal. The scheme is a generalization of the data transition tracking loop used in PSK systems. The performance of the loop was analyzed in terms of its mean-squared jitter and its effects on the data detection process in MASK and QASK systems.

Method for correcting imperfections on a surface

DOEpatents

Sweatt, William C.; Weed, John W.

1999-09-07

A process for producing near perfect optical surfaces. A previously polished optical surface is measured to determine its deviations from the desired perfect surface. A multi-aperture mask is designed based on this measurement and fabricated such that deposition through the mask will correct the deviations in the surface to an acceptable level. Various mask geometries can be used: variable individual aperture sizes using a fixed grid for the apertures or fixed aperture sizes using a variable aperture spacing. The imperfections are filled in using a vacuum deposition process with a very thin thickness of material such as silicon monoxide to produce an amorphous surface that bonds well to a glass substrate.

Study of a coronagraphic mask using evanescent waves.

PubMed

Buisset, Christophe; Rabbia, Yves; Lepine, Thierry; Alagao, Mary-Angelie; Ducrot, Elsa; Poshyachinda, Saran; Soonthornthum, Boonrucksar

2017-04-03

The evanescent wave coronagraph (EvWaCo) is a specific kind of band-limited coronagraph using the frustrated total internal reflection phenomenon to produce the coronagraphic effect (removing starlight from the image plane in order to make the stellar environment detectable). In this paper, we present a theoretical and experimental study of the EvWaCo coronagraphic mask. First, we calculate the theoretical transmission and we show that this mask is partially achromatic. Then, we present the experimental results obtained in unpolarized light at the wavelength λ≈900 nm and relative spectral bandwidth Δλ/λ≈6%. In particular, we show that the coronagraph provides a contrast down to a few 10^-6 at an angular distance of about ten Airy radii.

Orthographic and Phonological Contributions to Reading Development: Tracking Developmental Trajectories Using Masked Priming

ERIC Educational Resources Information Center

Ziegler, Johannes C.; Bertrand, Daisy; Lété, Bernard; Grainger, Jonathan

2014-01-01

The present study used a variant of masked priming to track the development of 2 marker effects of orthographic and phonological processing from Grade 1 through Grade 5 in a cross-sectional study. Pseudohomophone (PsH) priming served as a marker for phonological processing, whereas transposed-letter (TL) priming was a marker for coarse-grained…

Binaural signal detection - Equalization and cancellation theory.

NASA Technical Reports Server (NTRS)

Durlach, N. I.

1972-01-01

The improvement in masked-signal detection afforded by two ears (i.e., binaural unmasking) is explained on the basis of a descriptive model of the processing of binaural stimuli by a system consisting of two bandpass filters, an equalization and cancellation mechanism, and a decision device. The main ideas of the model are initially explained, and a general equation is derived for the purpose of making quantitative predictions. Comparisons are then made between various special cases of this equation and experimental data. Failures of the preliminary model in predicting the data are considered, and possible revisions are discussed.

Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

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

Li, Ting

The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE processmore » is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.« less

Patterned microstructures formed with MeV Au implantation in Si(1 0 0)

NASA Astrophysics Data System (ADS)

Rout, Bibhudutta; Greco, Richard R.; Zachry, Daniel P.; Dymnikov, Alexander D.; Glass, Gary A.

2006-09-01

Energetic (MeV) Au implantation in Si(1 0 0) (n-type) through masked micropatterns has been used to create layers resistant to KOH wet etching. Microscale patterns were produced in PMMA and SU(8) resist coatings on the silicon substrates using P-beam writing and developed. The silicon substrates were subsequently exposed using 1.5 MeV Au 3+ ions with fluences as high as 1 × 10 16 ions/cm 2 and additional patterns were exposed using copper scanning electron microscope calibration grids as masks on the silicon substrates. When wet etched with KOH microstructures were created in the silicon due to the resistance to KOH etching cause by the Au implantation. The process of combining the fabrication of masked patterns with P-beam writing with broad beam Au implantation through the masks can be a promising, cost-effective process for nanostructure engineering with Si.

The temporal dynamics of masked repetition picture priming effects: manipulations of stimulus-onset asynchrony (SOA) and prime duration

PubMed Central

Eddy, Marianna D.; Holcomb, Phillip J.

2010-01-01

The current study used event-related potentials (ERPs) and masked repetition priming to examine the time-course of picture processing. We manipulated the stimulus-onset asynchrony (110 ms, 230 ms, 350 ms, 470 ms) between repeated and unrepeated prime-target pairs while holding the prime duration constant (50 ms) (Experiment 1) as well as the prime duration (30 ms, 50 ms, 70 ms, 90 ms) (Experiment 2) with a constant SOA of 110 ms in a masked repetition priming paradigm with pictures. The aim of this study was to further elucidate the mechanisms underlying previously observed ERP components in masked priming with pictures. We found both the N/P190 and N400 are modulated by changes in prime duration and SOA, however, it appears that longer prime exposure rather than a longer SOA leads to more in-depth processing as indexed by larger N400 effects. PMID:20403342

Impact of the flu mask regulation on health care personnel influenza vaccine acceptance rates.

PubMed

Edwards, Frances; Masick, Kevin D; Armellino, Donna

2016-10-01

Achieving high vaccination rates of health care personnel (HCP) is critical in preventing influenza transmission from HCP to patients and from patients to HCP; however, acceptance rates remain low. In 2013, New York State adopted the flu mask regulation, requiring unvaccinated HCP to wear a mask when in areas where patients are present. The purpose of this study assessed the impact of the flu mask regulation on the HCP influenza vaccination rate. A 13-question survey was distributed electronically and manually to the HCP to examine their knowledge of influenza transmission and the influenza vaccine and their personal vaccine acceptance history and perception about the use of the mask while working if not vaccinated. There were 1,905 respondents; 87% accepted the influenza vaccine, and 63% were first-time recipients who agreed the regulation influenced their vaccination decision. Of the respondents who declined the vaccine, 72% acknowledge HCP are at risk for transmitting influenza to patients, and 56% reported they did not receive enough information to make an educated decision. The flu mask protocol may have influenced HCP's choice to be vaccinated versus wearing a mask. The study findings supported that HCP may not have adequate knowledge on the morbidity and mortality associated with influenza. Regulatory agencies need to consider an alternative approach to increase HCP vaccination, such as mandating the influenza vaccine for HCP. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Cloud Motion in the GOCI COMS Ocean Colour Data

NASA Technical Reports Server (NTRS)

Robinson, Wayne D.; Franz, Bryan A.; Mannino, Antonio; Ahn, Jae-Hyun

2016-01-01

The Geostationary Ocean Colour Imager (GOCI) instrument, on Koreas Communications, Oceans, and Meteorological Satellite (COMS), can produce a spectral artefact arising from the motion of clouds the cloud is spatially shifted and the amount of shift varies by spectral band. The length of time it takes to acquire all eight GOCI bands for a given slot (portion of a scene) is sucient to require that cloud motion be taken into account to fully mask or correct the eects of clouds in all bands. Inter-band correlations can be used to measure the amount of cloud shift, which can then be used to adjust the cloud mask so that the union of all shifted masks can act as a mask for all bands. This approach reduces the amount of masking required versus a simple expansion of the mask in all directions away from clouds. Cloud motion can also aect regions with unidentied clouds thin or fractional clouds that evade the cloud identication process yielding degraded quality in retrieved ocean colour parameters. Areas with moving and unidentied clouds require more elaborate masking algo-rithms to remove these degraded retrievals. Correction for the eects of moving fractional clouds may also be possible. The cloud shift information can be used to determine cloud motion and thus wind at the cloud levels on sub-minute timescales. The benecial and negative eects of moving clouds should be con-sidered for any ocean colour instrument design and associated data processing plans.

Assisted suicide by oxygen deprivation with helium at a Swiss right-to-die organisation.

PubMed

Ogden, Russel D; Hamilton, William K; Whitcher, Charles

2010-03-01

In Switzerland, right-to-die organisations assist their members with suicide by lethal drugs, usually barbiturates. One organisation, Dignitas, has experimented with oxygen deprivation as an alternative to sodium pentobarbital. To analyse the process of assisted suicide by oxygen deprivation with helium and a common face mask and reservoir bag. This study examined four cases of assisted suicide by oxygen deprivation using helium delivered via a face mask. Videos of the deaths were provided by the Zurich police. Dignitas provided protocol and consent information. One man and three women were assisted to death by oxygen deprivation. There was wide variation in the time to unconsciousness and the time to death, probably due to the poor mask fit. Swiss law prevented attendants from effectively managing the face mask apparatus. Purposeless movements of the extremities were disconcerting for Dignitas attendants, who are accustomed to assisting suicide with barbiturates. None of the dying individuals attempted self-rescue. The dying process of oxygen deprivation with helium is potentially quick and appears painless. It also bypasses the prescribing role of physicians, effectively demedicalising assisted suicide. Oxygen deprivation with a face mask is not acceptable because leaks are difficult to control and it may not eliminate rebreathing. These factors will extend time to unconsciousness and time to death. A hood method could reduce the problem of mask fit. With a hood, a flow rate of helium sufficient to provide continuous washout of expired gases would remedy problems observed with the mask.

Affect of the unconscious: Visually suppressed angry faces modulate our decisions

PubMed Central

Pajtas, Petra E.; Mahon, Bradford Z.; Nakayama, Ken; Caramazza, Alfonso

2016-01-01

Emotional and affective processing imposes itself over cognitive processes and modulates our perception of the surrounding environment. In two experiments, we addressed the issue of whether nonconscious processing of affect can take place even under deep states of unawareness, such as those induced by interocular suppression techniques, and can elicit an affective response that can influence our understanding of the surrounding environment. In Experiment 1, participants judged the likeability of an unfamiliar item—a Chinese character—that was preceded by a face expressing a particular emotion (either happy or angry). The face was rendered invisible through an interocular suppression technique (continuous flash suppression; CFS). In Experiment 2, backward masking (BM), a less robust masking technique, was used to render the facial expressions invisible. We found that despite equivalent phenomenological suppression of the visual primes under CFS and BM, different patterns of affective processing were obtained with the two masking techniques. Under BM, nonconscious affective priming was obtained for both happy and angry invisible facial expressions. However, under CFS, nonconscious affective priming was obtained only for angry facial expressions. We discuss an interpretation of this dissociation between affective processing and visual masking techniques in terms of distinct routes from the retina to the amygdala. PMID:23224765

Low cost solar array project. Cell and module formation research area. Process research of non-CZ silicon material

NASA Technical Reports Server (NTRS)

1983-01-01

Liquid diffusion masks and liquid dopants to replace the more expensive CVD SiO2 mask and gaseous diffusion processes were investigated. Silicon pellets were prepared in the silicon shot tower; and solar cells were fabricated using web grown where the pellets were used as a replenishment material. Verification runs were made using the boron dopant and liquid diffusion mask materials. The average of cells produced in these runs was 13%. The relationship of sheet resistivity, temperature, gas flows, and gas composition for the diffusion of the P-8 liquid phosphorus solution was investigated. Solar cells processed from web grown from Si shot material were evaluated, and results qualified the use of the material produced in the shot tower for web furnace feed stock.

Guidelines for Use of Personal Protective Equipment by Law Enforcement Personnel During a Terrorist Chemical Agent Incident. Revision 2

DTIC Science & Technology

2003-12-01

mask increases the protection to the neck area that is often left exposed without one. Testing of protective ensembles, as discussed later in this...protective mask. Most often the area of the neck under the chin is left exposed . Since chemical agents are also effective through skin absorption it...suit. Less heat buildup due to air transfer. Can be exposed to water making it the preferred type of suit for operations in support of

Efficient full-chip SRAF placement using machine learning for best accuracy and improved consistency

NASA Astrophysics Data System (ADS)

Wang, Shibing; Baron, Stanislas; Kachwala, Nishrin; Kallingal, Chidam; Sun, Dezheng; Shu, Vincent; Fong, Weichun; Li, Zero; Elsaid, Ahmad; Gao, Jin-Wei; Su, Jing; Ser, Jung-Hoon; Zhang, Quan; Chen, Been-Der; Howell, Rafael; Hsu, Stephen; Luo, Larry; Zou, Yi; Zhang, Gary; Lu, Yen-Wen; Cao, Yu

2018-03-01

Various computational approaches from rule-based to model-based methods exist to place Sub-Resolution Assist Features (SRAF) in order to increase process window for lithography. Each method has its advantages and drawbacks, and typically requires the user to make a trade-off between time of development, accuracy, consistency and cycle time. Rule-based methods, used since the 90 nm node, require long development time and struggle to achieve good process window performance for complex patterns. Heuristically driven, their development is often iterative and involves significant engineering time from multiple disciplines (Litho, OPC and DTCO). Model-based approaches have been widely adopted since the 20 nm node. While the development of model-driven placement methods is relatively straightforward, they often become computationally expensive when high accuracy is required. Furthermore these methods tend to yield less consistent SRAFs due to the nature of the approach: they rely on a model which is sensitive to the pattern placement on the native simulation grid, and can be impacted by such related grid dependency effects. Those undesirable effects tend to become stronger when more iterations or complexity are needed in the algorithm to achieve required accuracy. ASML Brion has developed a new SRAF placement technique on the Tachyon platform that is assisted by machine learning and significantly improves the accuracy of full chip SRAF placement while keeping consistency and runtime under control. A Deep Convolutional Neural Network (DCNN) is trained using the target wafer layout and corresponding Continuous Transmission Mask (CTM) images. These CTM images have been fully optimized using the Tachyon inverse mask optimization engine. The neural network generated SRAF guidance map is then used to place SRAF on full-chip. This is different from our existing full-chip MB-SRAF approach which utilizes a SRAF guidance map (SGM) of mask sensitivity to improve the contrast of optical image at the target pattern edges. In this paper, we demonstrate that machine learning assisted SRAF placement can achieve a superior process window compared to the SGM model-based SRAF method, while keeping the full-chip runtime affordable, and maintain consistency of SRAF placement . We describe the current status of this machine learning assisted SRAF technique and demonstrate its application to full chip mask synthesis and discuss how it can extend the computational lithography roadmap.

Automated Visual Inspection Of Integrated Circuits

NASA Astrophysics Data System (ADS)

Noppen, G.; Oosterlinck, Andre J.

1989-07-01

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

Three-dimensional printing for restoration of the donor face: A new digital technique tested and used in the first facial allotransplantation patient in Finland.

PubMed

Mäkitie, A A; Salmi, M; Lindford, A; Tuomi, J; Lassus, P

2016-12-01

Prosthetic mask restoration of the donor face is essential in current facial transplant protocols. The aim was to develop a new three-dimensional (3D) printing (additive manufacturing; AM) process for the production of a donor face mask that fulfilled the requirements for facial restoration after facial harvest. A digital image of a single test person's face was obtained in a standardized setting and subjected to three different image processing techniques. These data were used for the 3D modeling and printing of a donor face mask. The process was also tested in a cadaver setting and ultimately used clinically in a donor patient after facial allograft harvest. and Conclusions: All the three developed and tested techniques enabled the 3D printing of a custom-made face mask in a timely manner that is almost an exact replica of the donor patient's face. This technique was successfully used in a facial allotransplantation donor patient. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Visual masking and the dynamics of human perception, cognition, and consciousness A century of progress, a contemporary synthesis, and future directions.

PubMed

Ansorge, Ulrich; Francis, Gregory; Herzog, Michael H; Oğmen, Haluk

2008-07-15

The 1990s, the "decade of the brain," witnessed major advances in the study of visual perception, cognition, and consciousness. Impressive techniques in neurophysiology, neuroanatomy, neuropsychology, electrophysiology, psychophysics and brain-imaging were developed to address how the nervous system transforms and represents visual inputs. Many of these advances have dealt with the steady-state properties of processing. To complement this "steady-state approach," more recent research emphasized the importance of dynamic aspects of visual processing. Visual masking has been a paradigm of choice for more than a century when it comes to the study of dynamic vision. A recent workshop (http://lpsy.epfl.ch/VMworkshop/), held in Delmenhorst, Germany, brought together an international group of researchers to present state-of-the-art research on dynamic visual processing with a focus on visual masking. This special issue presents peer-reviewed contributions by the workshop participants and provides a contemporary synthesis of how visual masking can inform the dynamics of human perception, cognition, and consciousness.

Visual masking and the dynamics of human perception, cognition, and consciousness A century of progress, a contemporary synthesis, and future directions

PubMed Central

Ansorge, Ulrich; Francis, Gregory; Herzog, Michael H.; Öğmen, Haluk

2008-01-01

The 1990s, the “decade of the brain,” witnessed major advances in the study of visual perception, cognition, and consciousness. Impressive techniques in neurophysiology, neuroanatomy, neuropsychology, electrophysiology, psychophysics and brain-imaging were developed to address how the nervous system transforms and represents visual inputs. Many of these advances have dealt with the steady-state properties of processing. To complement this “steady-state approach,” more recent research emphasized the importance of dynamic aspects of visual processing. Visual masking has been a paradigm of choice for more than a century when it comes to the study of dynamic vision. A recent workshop (http://lpsy.epfl.ch/VMworkshop/), held in Delmenhorst, Germany, brought together an international group of researchers to present state-of-the-art research on dynamic visual processing with a focus on visual masking. This special issue presents peer-reviewed contributions by the workshop participants and provides a contemporary synthesis of how visual masking can inform the dynamics of human perception, cognition, and consciousness. PMID:20517493

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.

Spatial Attention Enhances Perceptual Processing of Single-Element Displays

NASA Technical Reports Server (NTRS)

Bacon, William; Johnston, James C.; Remington, Roger W.; Null, Cynthia H. (Technical Monitor)

1994-01-01

Shiu and Pashler (1993) reported that precueing masked, single-element displays had negligible effects on identification accuracy. They argued that spatial attention does not actually enhance stimulus perceptibility, but only reduces decision noise. Alternatively, such negative results may arise if cues are sub-optimal, or if masks place an insufficient premium on timely deployment of attention. We report results showing that valid cueing enhances processing of even single-element displays. Spatial attention does indeed enhance perceptual processes.

A methodology for cloud masking uncalibrated lidar signals

NASA Astrophysics Data System (ADS)

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

2018-04-01

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

Disposable surgical face masks for preventing surgical wound infection in clean surgery.

PubMed

Lipp, Allyson; Edwards, Peggy

2014-02-17

Surgical face masks were originally developed to contain and filter droplets containing microorganisms expelled from the mouth and nasopharynx of healthcare workers during surgery, thereby providing protection for the patient. However, there are several ways in which surgical face masks could potentially contribute to contamination of the surgical wound, e.g. by incorrect wear or by leaking air from the side of the mask due to poor string tension. To determine whether disposable surgical face masks worn by the surgical team during clean surgery prevent postoperative surgical wound infection. We searched The Cochrane Wounds Group Specialised Register on 23 October 2013; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. Randomised controlled trials (RCTs) and quasi-randomised controlled trials comparing the use of disposable surgical masks with the use of no mask. Two review authors extracted data independently. Three trials were included, involving a total of 2113 participants. There was no statistically significant difference in infection rates between the masked and unmasked group in any of the trials. From the limited results it is unclear whether the wearing of surgical face masks by members of the surgical team has any impact on surgical wound infection rates for patients undergoing clean surgery.

Mask industry assessment trend analysis

NASA Astrophysics Data System (ADS)

Hughes, Greg; Yun, Henry

2009-01-01

Microelectronics industry leaders routinely name the cost and cycle time of mask technology and mask supply as top critical issues. A survey was created with support from SEMATECH to gather information about the mask industry as an objective assessment of its overall condition. This year's survey data were presented in detail at BACUS and the detailed trend analysis presented at EMLC. The survey is designed with the input of semiconductor company mask technologists and merchant mask suppliers. This year's assessment is the seventh in the current series of annual reports. With continued 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. The report 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 on critical path issues. This year's survey is basically the same as the surveys in 2005 through 2007. Questions are grouped into seven categories: General Business Profile Information, Data Processing, Yields and Yield Loss, Mechanisms, Delivery Times, Returns, and Services. (Examples are given below). Within each category is a multitude of questions that creates a detailed profile of both the business and technical status of the critical mask industry.

Mask industry assessment: 2009

NASA Astrophysics Data System (ADS)

Hughes, Greg; Yun, Henry

2009-10-01

Microelectronics industry leaders routinely name the cost and cycle time of mask technology and mask supply as top critical issues. A survey was created with support from SEMATECH and administered by David Powell Consulting to gather information about the mask industry as an objective assessment of its overall condition. The survey is designed with the input of semiconductor company mask technologists and merchant mask suppliers. This year's assessment is the eighth 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. The report 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 is basically the same as the 2005 through 2008 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 is a multitude of questions that create a detailed profile of both the business and technical status of the critical mask industry. This in combination with the past surveys represents a comprehensive view of changes in the industry.

Development of an Operational Land Water Mask for MODIS Collection 6, and Influence on Downstream Data Products

NASA Technical Reports Server (NTRS)

Carroll, M. L.; DiMiceli, C. M.; Townshend, J. R. G.; Sohlberg, R. A.; Elders, A. I.; Devadiga, S.; Sayer, A. M.; Levy, R. C.

2016-01-01

Data from the Moderate Resolution Imaging Spectro-radiometer (MODIS)on-board the Earth Observing System Terra and Aqua satellites are processed using a land water mask to determine when an algorithm no longer needs to be run or when an algorithm needs to follow a different pathway. Entering the fourth reprocessing (Collection 6 (C6)) the MODIS team replaced the 1 km water mask with a 500 m water mask for improved representation of the continental surfaces. The new water mask represents more small water bodies for an overall increase in water surface from 1 to 2 of the continental surface. While this is still a small fraction of the overall global surface area the increase is more dramatic in certain areas such as the Arctic and Boreal regions where there are dramatic increases in water surface area in the new mask. MODIS products generated by the on-going C6 reprocessing using the new land water mask show significant impact in areas with high concentrations of change in the land water mask. Here differences between the Collection 5 (C5) and C6 water masks and the impact of these differences on the MOD04 aerosol product and the MOD11 land surface temperature product are shown.

Process variation challenges and resolution in the negative-tone develop double patterning for 20nm and below technology node

NASA Astrophysics Data System (ADS)

Mehta, Sohan S.; Ganta, Lakshmi K.; Chauhan, Vikrant; Wu, Yixu; Singh, Sunil; Ann, Chia; Subramany, Lokesh; Higgins, Craig; Erenturk, Burcin; Srivastava, Ravi; Singh, Paramjit; Koh, Hui Peng; Cho, David

2015-03-01

Immersion based 20nm technology node and below becoming very challenging to chip designers, process and integration due to multiple patterning to integrate one design layer . Negative tone development (NTD) processes have been well accepted by industry experts for enabling technologies 20 nm and below. 193i double patterning is the technology solution for pitch down to 80 nm. This imposes tight control in critical dimension(CD) variation in double patterning where design patterns are decomposed in two different masks such as in litho-etch-litho etch (LELE). CD bimodality has been widely studied in LELE double patterning. A portion of CD tolerance budget is significantly consumed by variations in CD in double patterning. The objective of this work is to study the process variation challenges and resolution in the Negative Tone Develop Process for 20 nm and Below Technology Node. This paper describes the effect of dose slope on CD variation in negative tone develop LELE process. This effect becomes even more challenging with standalone NTD developer process due to q-time driven CD variation. We studied impact of different stacks with combination of binary and attenuated phase shift mask and estimated dose slope contribution individually from stack and mask type. Mask 3D simulation was carried out to understand theoretical aspect. In order to meet the minimum insulator requirement for the worst case on wafer the overlay and critical dimension uniformity (CDU) budget margins have slimmed. Besides the litho process and tool control using enhanced metrology feedback, the variation control has other dependencies too. Color balancing between the two masks in LELE is helpful in countering effects such as iso-dense bias, and pattern shifting. Dummy insertion and the improved decomposition techniques [2] using multiple lower priority constraints can help to a great extent. Innovative color aware routing techniques [3] can also help with achieving more uniform density and color balanced layouts.

[Laryngeal mask for intubation (Fastrach)].

PubMed

Añez Simón, C; Boada Pié, S; Solsona Dellá, B

2000-10-01

The laryngeal mask for intubation (MLI), or "Fastrach", is a new device designed by Brain for airway management. The MLI, a modified version of the conventional laryngeal mask, allows for blind intubation through the device using endotracheal tubes up to 8 mm in diameter. Insertion with the head in a neutral position makes this system useful for managing the airway when neck injury is present. The device has been used successfully in patients assessed as having difficult-to-manage airways and its use in emergencies inside or outside the hospital is promising. The MLI has been used with high rates of success in combination with other techniques such as fiberoptic bronchoscopy (success rate 99 to 100%) and transillumination (95 to 100% success rate) in patients whose airways have been considered difficult to manage. Given such high rates of success for MLI placement (95 to 100%) and for blind orotracheal intubation (81 to 100%), the Fastrach may offer an alternative to the conventional laryngeal mask in algorithms for airway management.

The role of low-spatial frequencies in lexical decision and masked priming.

PubMed

Boden, C; Giaschi, D

2009-04-01

Spatial frequency filtering was used to test the hypotheses that low-spatial frequency information in printed text can: (1) lead to a rapid lexical decision or (2) facilitate word recognition. Adult proficient readers made lexical decisions in unprimed and masked repetition priming experiments with unfiltered, low-pass, high-pass and notch filtered letter strings. In the unprimed experiments, a filtered target was presented for 105 or 400 ms followed by a pattern mask. Sensitivity (d') was lowest for the low-pass filtered targets at both durations with a bias towards a 'non-word' response. Sensitivity was higher in the high-pass and notch filter conditions. In the priming experiments, a forward mask was followed by a filtered prime then an unfiltered target. Primed words, but not non-words, were identified faster than unprimed words in both the low-pass and high-pass filtered conditions. These results do not support a unique role for low-spatial frequency information in either facilitating or making rapid lexical decisions.

Tissue Photolithography

NASA Technical Reports Server (NTRS)

Wade, Lawrence A.; Kartalov, Emil; Shibata, Darryl; Taylor, Clive

2011-01-01

Tissue lithography will enable physicians and researchers to obtain macromolecules with high purity (greater than 90 percent) from desired cells in conventionally processed, clinical tissues by simply annotating the desired cells on a computer screen. After identifying the desired cells, a suitable lithography mask will be generated to protect the contents of the desired cells while allowing destruction of all undesired cells by irradiation with ultraviolet light. The DNA from the protected cells can be used in a number of downstream applications including DNA sequencing. The purity (i.e., macromolecules isolated form specific cell types) of such specimens will greatly enhance the value and information of downstream applications. In this method, the specific cells are isolated on a microscope slide using photolithography, which will be faster, more specific, and less expensive than current methods. It relies on the fact that many biological molecules such as DNA are photosensitive and can be destroyed by ultraviolet irradiation. Therefore, it is possible to protect the contents of desired cells, yet destroy undesired cells. This approach leverages the technologies of the microelectronics industry, which can make features smaller than 1 micrometer with photolithography. A variety of ways has been created to achieve identification of the desired cell, and also to designate the other cells for destruction. This can be accomplished through chrome masks, direct laser writing, and also active masking using dynamic arrays. Image recognition is envisioned as one method for identifying cell nuclei and cell membranes. The pathologist can identify the cells of interest using a microscopic computerized image of the slide, and appropriate custom software. In one of the approaches described in this work, the software converts the selection into a digital mask that can be fed into a direct laser writer, e.g. the Heidelberg DWL66. Such a machine uses a metalized glass plate (with chrome metallization) on which there is a thin layer of photoresist. The laser transfers the digital mask onto the photoresist by direct writing, with typical best resolution of 2 micrometers. The plate is then developed to remove the exposed photoresist, which leaves the exposed areas susceptible to chemical chrome etch. The etch removes the unprotected chrome. The rest of the photoresist is then removed, by either ultraviolet organic solvent or over-development. The remaining chrome pattern is quickly oxidized by atmospheric exposure (typically within 30 seconds). The ready chrome mask is now applied to the tissue slide and aligned manually, or using automatic software and pre-designed alignment marks. The slide plate sandwich is then exposed to UV to destroy the DNA of the unwanted cells. The slide and plate are separated and the slide is processed in a standard way to prepare for polymerase chain reaction (PCR) and potential identification of cancer sequences.

Single-Run Single-Mask Inductively-Coupled-Plasma Reactive-Ion-Etching Process for Fabricating Suspended High-Aspect-Ratio Microstructures

NASA Astrophysics Data System (ADS)

Yang, Yao-Joe; Kuo, Wen-Cheng; Fan, Kuang-Chao

2006-01-01

In this work, we present a single-run single-mask (SRM) process for fabricating suspended high-aspect-ratio structures on standard silicon wafers using an inductively coupled plasma-reactive ion etching (ICP-RIE) etcher. This process eliminates extra fabrication steps which are required for structure release after trench etching. Released microstructures with 120 μm thickness are obtained by this process. The corresponding maximum aspect ratio of the trench is 28. The SRM process is an extended version of the standard process proposed by BOSCH GmbH (BOSCH process). The first step of the SRM process is a standard BOSCH process for trench etching, then a polymer layer is deposited on trench sidewalls as a protective layer for the subsequent structure-releasing step. The structure is released by dry isotropic etching after the polymer layer on the trench floor is removed. All the steps can be integrated into a single-run ICP process. Also, only one mask is required. Therefore, the process complexity and fabrication cost can be effectively reduced. Discussions on each SRM step and considerations for avoiding undesired etching of the silicon structures during the release process are also presented.

Registration performance on EUV masks using high-resolution registration metrology

NASA Astrophysics Data System (ADS)

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

2016-10-01

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

Vortex via process: analysis and mask fabrication for contact CDs <80 nm

NASA Astrophysics Data System (ADS)

Levenson, Marc D.; Tan, Sze M.; Dai, Grace; Morikawa, Yasutaka; Hayashi, Naoya; Ebihara, Takeaki

2003-06-01

In an optical vortex, the wavefront spirals like a corkscrew, rather than forming planes or spheres. Since any nonzero optical amplitude must have a well-defined phase, the axis of a vortex is always dark. Printed in negative resist at 248nm and NA=0.63, 250nm pitch vortex arrays would produce contact holes with 80nm0.6 can be patterned using a chromeless phase-edge mask composed of rectangles with nominal phases of 0°, 90°, 180° and 270°. Analytic and numerical calculations have been performed to characterize the aerial images projected from such vortex masks using the Kirchhoff-approximation and rigorous EMF methods. Combined with resist simulations, these analyses predict process windows with ~10%Elat and >200nm DOF for 80nm CDs on pitches greater than or equal to 250nm at σ greater than or equal to 0.15. Smaller CDs and pitches are possible with shorter wavelength and larger NA while larger pitches give rise to larger CDs. At pitch >0.8μm, the vortices begin to print independently for σ greater than or equal to 0.3. Such "independent" vortices have a quasi-isofocal dose that gives rise to 100nm contacts with Elat>9% and DOF>500nm at σ=0.3. The extra darkness of the nominal 270° phase step can be accommodated by fine-tuning the etch depth. A reticle fabrication process that achieves the required alignment and vertical wall profiles has been exercised and test masks analyzed. In an actual chip design, unwanted vortices and phase step images would be erased from the resist pattern by exposing the wafer with a second, more conventional trim mask. Vortex via placement is consistent with the coarse-gridded grating design paradigms which would - if widely exercised - lower the cost of the required reticles. Compared to other ways of producing deep sub-wavelength contacts, the vortex via process requires fewer masks and reduces the overlay and process control challenges. A high resolution negative-working resist process is essential, however.

Effects of masker frequency and duration in forward masking: further evidence for the influence of peripheral nonlinearity.

PubMed

Oxenham, A J; Plack, C J

2000-12-01

Forward masking has often been thought of in terms of neural adaptation, with nonlinearities in the growth and decay of forward masking being accounted for by the nonlinearities inherent in adaptation. In contrast, this study presents further evidence for the hypothesis that forward masking can be described as a linear process, once peripheral, mechanical nonlinearities are taken into account. The first experiment compares the growth of masking for on- and off-frequency maskers. Signal thresholds were measured as a function of masker level for three masker-signal intervals of 0, 10, and 30 ms. The brief 4-kHz sinusoidal signal was masked by a 200-ms sinusoidal forward masker which had a frequency of either 2.4 kHz (off-frequency) or 4 kHz (on-frequency). As in previous studies, for the on-frequency condition, the slope of the function relating signal threshold to masker level became shallower as the delay between the masker and signal was increased. In contrast, the slopes for the off-frequency condition were independent of masker-signal delay and had a value of around unity, indicating linear growth of masking for all masker-signal delays. In the second experiment, a broadband Gaussian noise forward masker was used to mask a brief 6-kHz sinusoidal signal. The spectrum level of the masker was either 0 or 40 dB (re: 20 microPa). The gap between the masker and signal was either 0 or 20 ms. Signal thresholds were measured for masker durations from 5 to 200 ms. The effect of masker duration was found to depend more on signal level than on gap duration or masker level. Overall, the results support the idea that forward masking can be modeled as a linear process, preceded by a static nonlinearity resembling that found on the basilar membrane.

Masking technique for coating thickness control on large and strongly curved aspherical optics.

PubMed

Sassolas, B; Flaminio, R; Franc, J; Michel, C; Montorio, J-L; Morgado, N; Pinard, L

2009-07-01

We discuss a method to control the coating thickness deposited onto large and strongly curved optics by ion beam sputtering. The technique uses an original design of the mask used to screen part of the sputtered materials. A first multielement mask is calculated from the measured two-dimensional coating thickness distribution. Then, by means of an iterative process, the final mask is designed. By using such a technique, it has been possible to deposit layers of tantalum pentoxide having a high thickness gradient onto a curved substrate 500 mm in diameter. Residual errors in the coating thickness profile are below 0.7%.

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

NASA Astrophysics Data System (ADS)

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

2013-04-01

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

Psychophysical "blinding" methods reveal a functional hierarchy of unconscious visual processing.

PubMed

Breitmeyer, Bruno G

2015-09-01

Numerous non-invasive experimental "blinding" methods exist for suppressing the phenomenal awareness of visual stimuli. Not all of these suppressive methods occur at, and thus index, the same level of unconscious visual processing. This suggests that a functional hierarchy of unconscious visual processing can in principle be established. The empirical results of extant studies that have used a number of different methods and additional reasonable theoretical considerations suggest the following tentative hierarchy. At the highest levels in this hierarchy is unconscious processing indexed by object-substitution masking. The functional levels indexed by crowding, the attentional blink (and other attentional blinding methods), backward pattern masking, metacontrast masking, continuous flash suppression, sandwich masking, and single-flash interocular suppression, fall at progressively lower levels, while unconscious processing at the lowest levels is indexed by eye-based binocular-rivalry suppression. Although unconscious processing levels indexed by additional blinding methods is yet to be determined, a tentative placement at lower levels in the hierarchy is also given for unconscious processing indexed by Troxler fading and adaptation-induced blindness, and at higher levels in the hierarchy indexed by attentional blinding effects in addition to the level indexed by the attentional blink. The full mapping of levels in the functional hierarchy onto cortical activation sites and levels is yet to be determined. The existence of such a hierarchy bears importantly on the search for, and the distinctions between, neural correlates of conscious and unconscious vision. Copyright © 2015 Elsevier Inc. All rights reserved.

Method of fabricating a 3-dimensional tool master

DOEpatents

Bonivert, William D.; Hachman, John T.

2002-01-01

The invention is a method for the fabrication of an imprint tool master. The process begins with a metallic substrate. A layer of photoresist is placed onto the metallic substrate and a image pattern mask is then aligned to the mask. The mask pattern has opaque portions that block exposure light and "open" or transparent portions which transmit exposure light. The photoresist layer is then exposed to light transmitted through the "open" portions of the first image pattern mask and the mask is then removed. A second layer of photoresist then can be placed onto the first photoresist layer and a second image pattern mask may be placed on the second layer of photoresist. The second layer of photoresist is exposed to light, as before, and the second mask removed. The photoresist layers are developed simultaneously to produce a multi-level master mandrel upon which a conductive film is formed. A tool master can now be formed onto the conductive film. An imprint tool is then produced from the tool master. In one embodiment, nickel is electroplated onto the tool master to produce a three-dimensional imprint tool.

Selective Plasma Deposition of Fluorocarbon Films on SAMs

NASA Technical Reports Server (NTRS)

Crain, Mark M., III; Walsh, Kevin M.; Cohn, Robert W.

2006-01-01

A dry plasma process has been demonstrated to be useful for the selective modification of self-assembled monolayers (SAMs) of alkanethiolates. These SAMs are used, during the fabrication of semiconductor electronic devices, as etch masks on gold layers that are destined to be patterned and incorporated into the devices. The selective modification involves the formation of fluorocarbon films that render the SAMs more effective in protecting the masked areas of the gold against etching by a potassium iodide (KI) solution. This modification can be utilized, not only in the fabrication of single electronic devices but also in the fabrication of integrated circuits, microelectromechanical systems, and circuit boards. In the steps that precede the dry plasma process, a silicon mold in the desired pattern is fabricated by standard photolithographic techniques. A stamp is then made by casting polydimethylsiloxane (commonly known as silicone rubber) in the mold. The stamp is coated with an alkanethiol solution, then the stamp is pressed on the gold layer of a device to be fabricated in order to deposit the alkanethiol to form an alkanethiolate SAM in the desired pattern (see figure). Next, the workpiece is exposed to a radio-frequency plasma generated from a mixture of CF4 and H2 gases. After this plasma treatment, the SAM is found to be modified, while the exposed areas of gold remain unchanged. This dry plasma process offers the potential for forming masks superior to those formed in a prior wet etching process. Among the advantages over the wet etching process are greater selectivity, fewer pin holes in the masks, and less nonuniformity of the masks. The fluorocarbon films formed in this way may also be useful as intermediate layers for subsequent fabrication steps and as dielectric layers to be incorporated into finished products.

The Attentional Blink Is Not Affected by Backward Masking of T2, T2-Mask SOA, or Level of T2 Impoverishment

ERIC Educational Resources Information Center

Jannati, Ali; Spalek, Thomas M.; Lagroix, Hayley E. P.; Di Lollo, Vincent

2012-01-01

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…

Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation

PubMed Central

Tapia, Evelina; Beck, Diane M.

2014-01-01

A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness. PMID:25374548

Click trains and the rate of information processing: does "speeding up" subjective time make other psychological processes run faster?

PubMed

Jones, Luke A; Allely, Clare S; Wearden, John H

2011-02-01

A series of experiments demonstrated that a 5-s train of clicks that have been shown in previous studies to increase the subjective duration of tones they precede (in a manner consistent with "speeding up" timing processes) could also have an effect on information-processing rate. Experiments used studies of simple and choice reaction time (Experiment 1), or mental arithmetic (Experiment 2). In general, preceding trials by clicks made response times significantly shorter than those for trials without clicks, but white noise had no effects on response times. Experiments 3 and 4 investigated the effects of clicks on performance on memory tasks, using variants of two classic experiments of cognitive psychology: Sperling's (1960) iconic memory task and Loftus, Johnson, and Shimamura's (1985) iconic masking task. In both experiments participants were able to recall or recognize significantly more information from stimuli preceded by clicks than those preceded by silence.

A method for interactive satellite failure diagnosis: Towards a connectionist solution

NASA Technical Reports Server (NTRS)

Bourret, P.; Reggia, James A.

1989-01-01

Various kinds of processes which allow one to make a diagnosis are analyzed. The analyses then focuses on one of these processes used for satellite failure diagnosis. This process consists of sending the satellite instructions about system status alterations: to mask the effects of one possible component failure or to look for additional abnormal measures. A formal model of this process is given. This model is an extension of a previously defined connectionist model which allows computation of ratios between the likelihoods of observed manifestations according to various diagnostic hypotheses. The expected mean value of these likelihood measures for each possible status of the satellite can be computed in a similar way. Therefore, it is possible to select the most appropriate status according to three different purposes: to confirm an hypothesis, to eliminate an hypothesis, or to choose between two hypotheses. Finally, a first connectionist schema of computation of these expected mean values is given.

Instantaneous phase-shifting Fizeau interferometry with high-speed pixelated phase-mask camera

NASA Astrophysics Data System (ADS)

Yatagai, Toyohiko; Jackin, Boaz Jessie; Ono, Akira; Kiyohara, Kosuke; Noguchi, Masato; Yoshii, Minoru; Kiyohara, Motosuke; Niwa, Hayato; Ikuo, Kazuyuki; Onuma, Takashi

2015-08-01

A Fizeou interferometer with instantaneous phase-shifting ability using a Wollaston prism is designed. to measure dynamic phase change of objects, a high-speed video camera of 10-5s of shutter speed is used with a pixelated phase-mask of 1024 × 1024 elements. The light source used is a laser of wavelength 532 nm which is split into orthogonal polarization states by passing through a Wollaston prism. By adjusting the tilt of the reference surface it is possible to make the reference and object beam with orthogonal polarizations states to coincide and interfere. Then the pixelated phase-mask camera calculate the phase changes and hence the optical path length difference. Vibration of speakers and turbulence of air flow were successfully measured in 7,000 frames/sec.

Plasma-Induced, Self-Masking, One-Step Approach to an Ultrabroadband Antireflective and Superhydrophilic Subwavelength Nanostructured Fused Silica Surface.

PubMed

Ye, Xin; Shao, Ting; Sun, Laixi; Wu, Jingjun; Wang, Fengrui; He, Junhui; Jiang, Xiaodong; Wu, Wei-Dong; Zheng, Wanguo

2018-04-25

In this work, antireflective and superhydrophilic subwavelength nanostructured fused silica surfaces have been created by one-step, self-masking reactive ion etching (RIE). Bare fused silica substrates with no mask were placed in a RIE vacuum chamber, and then nanoscale fluorocarbon masks and subwavelength nanostructures (SWSs) automatically formed on these substrate after the appropriate RIE plasma process. The mechanism of plasma-induced self-masking SWS has been proposed in this paper. Plasma parameter effects on the morphology of SWS have been investigated to achieve perfect nanocone-like SWS for excellent antireflection, including process time, reactive gas, and pressure of the chamber. Optical properties, i.e., antireflection and optical scattering, were simulated by the finite difference time domain (FDTD) method. Calculated data agree well with the experiment results. The optimized SWS show ultrabroadband antireflective property (up to 99% from 500 to 1360 nm). An excellent improvement of transmission was achieved for the deep-ultraviolet (DUV) range. The proposed low-cost, highly efficient, and maskless method was applied to achieve ultrabroadband antireflective and superhydrophilic SWSs on a 100 mm optical window, which promises great potential for applications in the automotive industry, goggles, and optical devices.

Phase-shifting coronagraph

NASA Astrophysics Data System (ADS)

Hénault, François; Carlotti, Alexis; Vérinaud, Christophe

2017-09-01

With the recent commissioning of ground instruments such as SPHERE or GPI and future space observatories like WFIRST-AFTA, coronagraphy should probably become the most efficient tool for identifying and characterizing extrasolar planets in the forthcoming years. Coronagraphic instruments such as Phase mask coronagraphs (PMC) are usually based on a phase mask or plate located at the telescope focal plane, spreading the starlight outside the diameter of a Lyot stop that blocks it. In this communication is investigated the capability of a PMC to act as a phase-shifting wavefront sensor for better control of the achieved star extinction ratio in presence of the coronagraphic mask. We discuss the two main implementations of the phase-shifting process, either introducing phase-shifts in a pupil plane and sensing intensity variations in an image plane, or reciprocally. Conceptual optical designs are described in both cases. Numerical simulations allow for better understanding of the performance and limitations of both options, and optimizing their fundamental parameters. In particular, they demonstrate that the phase-shifting process is a bit more efficient when implemented into an image plane, and is compatible with the most popular phase masks currently employed, i.e. fourquadrants and vortex phase masks.

Abnormal auditory forward masking pattern in the brainstem response of individuals with Asperger syndrome

PubMed Central

Källstrand, Johan; Olsson, Olle; Nehlstedt, Sara Fristedt; Sköld, Mia Ling; Nielzén, Sören

2010-01-01

Abnormal auditory information processing has been reported in individuals with autism spectrum disorders (ASD). In the present study auditory processing was investigated by recording auditory brainstem responses (ABRs) elicited by forward masking in adults diagnosed with Asperger syndrome (AS). Sixteen AS subjects were included in the forward masking experiment and compared to three control groups consisting of healthy individuals (n = 16), schizophrenic patients (n = 16) and attention deficit hyperactivity disorder patients (n = 16), respectively, of matching age and gender. The results showed that the AS subjects exhibited abnormally low activity in the early part of their ABRs that distinctly separated them from the three control groups. Specifically, wave III amplitudes were significantly lower in the AS group than for all the control groups in the forward masking condition (P < 0.005), which was not the case in the baseline condition. Thus, electrophysiological measurements of ABRs to complex sound stimuli (eg, forward masking) may lead to a better understanding of the underlying neurophysiology of AS. Future studies may further point to specific ABR characteristics in AS individuals that separate them from individuals diagnosed with other neurodevelopmental diseases. PMID:20628629

Forward Masking of the Speech-Evoked Auditory Brainstem Response.

PubMed

Hodge, Sarah E; Menezes, Denise C; Brown, Kevin D; Grose, John H

2018-02-01

The hypothesis tested was that forward masking of the speech-evoked auditory brainstem response (sABR) increases peak latency as an inverse function of masker-signal interval (Δt), and that the overall persistence of forward masking is age dependent. Older listeners exhibit deficits in forward masking. If forward-masked sABRs provide an objective measure of the susceptibility of speech sounds to prior stimulation, then this provides a novel approach to examining the age dependence of temporal processing. A /da/ stimulus forward masked by speech-shaped noise (Δt = 4-64 ms) was used to measure sABRs in 10 younger and nine older participants. Forward masking of subsegments of the /da/ stimulus (Δt = 16 ms) and click trains (Δt = 0-64 ms) was also measured. Forward-masked sABRs from young participants showed an increase in latency with decreasing Δt for the initial peak. Latency shifts for later peaks were smaller and more uniform. None of the peak latencies returned to baseline by Δt = 64 ms. Forward-masked /da/ subsegments showed peak latency shifts that did not depend simply on peak position, while forward-masked click trains showed latency shifts that were dependent on click position. The sABRs from older adults were less robust but confirmed the viability of the approach. Forward masking of the sABR provides an objective measure of the susceptibility of the auditory system to prior stimulation. Failure of recovery functions to return to baseline suggests an interaction between forward masking by the prior masker and temporal effects within the stimulus itself.

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.

Objective evaluation of the knocking sound of a diesel engine considering the temporal and frequency masking effect simultaneously

NASA Astrophysics Data System (ADS)

Yun, Dong-Un; Lee, Sang-Kwon

2017-06-01

In this paper, we present a novel method for an objective evaluation of knocking noise emitted by diesel engines based on the temporal and frequency masking theory. The knocking sound of a diesel engine is a vibro-acoustic sound correlated with the high-frequency resonances of the engine structure and a periodic impulsive sound with amplitude modulation. Its period is related to the engine speed and includes specific frequency bands related to the resonances of the engine structure. A knocking sound with the characteristics of a high-frequency impulsive wave can be masked by low-frequency sounds correlated with the harmonics of the firing frequency and broadband noise. The degree of modulation of the knocking sound signal was used for such objective evaluations in previous studies, without considering the masking effect. However, the frequency masking effect must be considered for the objective evaluation of the knocking sound. In addition to the frequency masking effect, the temporal masking effect occurs because the period of the knocking sound changes according to the engine speed. Therefore, an evaluation method considering the temporal and frequency masking effect is required to analyze the knocking sound objectively. In this study, an objective evaluation method considering the masking effect was developed based on the masking theory of sound and signal processing techniques. The method was applied successfully for the objective evaluation of the knocking sound of a diesel engine.

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.

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.

Prewarping techniques in imaging: applications in nanotechnology and biotechnology

NASA Astrophysics Data System (ADS)

Poonawala, Amyn; Milanfar, Peyman

2005-03-01

In all imaging systems, the underlying process introduces undesirable distortions that cause the output signal to be a warped version of the input. When the input to such systems can be controlled, pre-warping techniques can be employed which consist of systematically modifying the input such that it cancels out (or compensates for) the process losses. In this paper, we focus on the mask (reticle) design problem for 'optical micro-lithography', a process similar to photographic printing used for transferring binary circuit patterns onto silicon wafers. We use a pixel-based mask representation and model the above process as a cascade of convolution (aerial image formation) and thresholding (high-contrast recording) operations. The pre-distorted mask is obtained by minimizing the norm of the difference between the 'desired' output image and the 'reproduced' output image. We employ the regularization framework to ensure that the resulting masks are close-to-binary as well as simple and easy to fabricate. Finally, we provide insight into two additional applications of pre-warping techniques. First is 'e-beam lithography', used for fabricating nano-scale structures, and second is 'electronic visual prosthesis' which aims at providing limited vision to the blind by using a prosthetic retinally implanted chip capable of electrically stimulating the retinal neuron cells.

Using the Leitz LMS 2000 for monitoring and improvement of an e-beam

NASA Astrophysics Data System (ADS)

Blaesing-Bangert, Carola; Roeth, Klaus-Dieter; Ogawa, Yoichi

1994-11-01

Kaizen--a continuously improving--is a philosophy lived in Japan which is also becoming more and more important in Western companies. To implement this philosophy in the semiconductor industry, a high performance metrology tool is essential to determine the status of production quality periodically. An important prerequisite for statistical process control is the high stability of the metrology tool over several months or years; the tool-induced shift should be as small as possible. The pattern placement metrology tool Leitz LMS 2000 has been used in a major European mask house for several years now to qualify masks within the tightest specifications and to monitor the MEBES III and its cassettes. The mask shop's internal specification for the long term repeatability of the pattern placement metrology tool is 19 nm instead of 42 nm as specified by the supplier of the tool. Then the process capability of the LMS 2000 over 18 months is represented by an average cpk value of 2.8 for orthogonality, 5.2 for x-scaling, and 3.0 for y-scaling. The process capability of the MEBES III and its cassettes was improved in the past years. For instance, 100% of the masks produced with a process tolerance of +/- 200 nm are now within this limit.

An economic analysis for optimal distributed computing resources for mask synthesis and tape-out in production environment

NASA Astrophysics Data System (ADS)

Cork, Chris; Lugg, Robert; Chacko, Manoj; Levi, Shimon

2005-06-01

With the exponential increase in output database size due to the aggressive optical proximity correction (OPC) and resolution enhancement technique (RET) required for deep sub-wavelength process nodes, the CPU time required for mask tape-out continues to increase significantly. For integrated device manufacturers (IDMs), this can impact the time-to-market for their products where even a few days delay could have a huge commercial impact and loss of market window opportunity. For foundries, a shorter turnaround time provides a competitive advantage in their demanding market, too slow could mean customers looking elsewhere for these services; while a fast turnaround may even command a higher price. With FAB turnaround of a mature, plain-vanilla CMOS process of around 20-30 days, a delay of several days in mask tapeout would contribute a significant fraction to the total time to deliver prototypes. Unlike silicon processing, masks tape-out time can be decreased by simply purchasing extra computing resources and software licenses. Mask tape-out groups are taking advantage of the ever-decreasing hardware cost and increasing power of commodity processors. The significant distributability inherent in some commercial Mask Synthesis software can be leveraged to address this critical business issue. Different implementations have different fractions of the code that cannot be parallelized and this affects the efficiency with which it scales, as is described by Amdahl"s law. Very few are efficient enough to allow the effective use of 1000"s of processors, enabling run times to drop from days to only minutes. What follows is a cost aware methodology to quantify the scalability of this class of software, and thus act as a guide to estimating the optimal investment in terms of hardware and software licenses.

Less is more: Neural activity during very brief and clearly visible exposure to phobic stimuli.

PubMed

Siegel, Paul; Warren, Richard; Wang, Zhishun; Yang, Jie; Cohen, Don; Anderson, Jason F; Murray, Lilly; Peterson, Bradley S

2017-05-01

Research on automatic processes in fear has emphasized the provocation of fear responses rather than their attenuation. We have previously shown that the repeated presentation of feared images without conscious awareness via backward masking reduces avoidance of a live tarantula in spider-phobic participants. Herein we investigated the neural basis for these adaptive effects of masked exposure. 21 spider-phobic and 21 control participants, identified by a psychiatric interview, fear questionnaire, and approaching a live tarantula, viewed stimuli in each of three conditions: (1) very brief exposure (VBE) to masked images of spiders, severely limited awareness; (2) clearly visible exposure (CVE) to spiders, full awareness; and (3) masked images of flowers (control), severely limited awareness. Only VBE to masked spiders generated neural activity more strongly in phobic than in control participants, within subcortical fear, attention, higher-order language, and vision systems. Moreover, VBE activated regions that support fear processing in phobic participants without causing them to experience fear consciously. Counter-intuitively, CVE to the same spiders generated stronger neural activity in control rather than phobic participants within these and other systems. CVE deactivated regions supporting fear regulation and caused phobic participants to experience fear. CVE-induced activations also correlated with measures of explicit fear ratings, whereas VBE-induced activations correlated with measures of implicit fear (color-naming interference of spider words). These multiple dissociations between the effects of VBE and CVE to spiders suggest that limiting awareness of exposure to phobic stimuli through visual masking paradoxically facilitates their processing, while simultaneously minimizing the experience of fear. Hum Brain Mapp 38:2466-2481, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Massively-parallel FDTD simulations to address mask electromagnetic effects in hyper-NA immersion lithography

NASA Astrophysics Data System (ADS)

Tirapu Azpiroz, Jaione; Burr, Geoffrey W.; Rosenbluth, Alan E.; Hibbs, Michael

2008-03-01

In the Hyper-NA immersion lithography regime, the electromagnetic response of the reticle is known to deviate in a complicated manner from the idealized Thin-Mask-like behavior. Already, this is driving certain RET choices, such as the use of polarized illumination and the customization of reticle film stacks. Unfortunately, full 3-D electromagnetic mask simulations are computationally intensive. And while OPC-compatible mask electromagnetic field (EMF) models can offer a reasonable tradeoff between speed and accuracy for full-chip OPC applications, full understanding of these complex physical effects demands higher accuracy. Our paper describes recent advances in leveraging High Performance Computing as a critical step towards lithographic modeling of the full manufacturing process. In this paper, highly accurate full 3-D electromagnetic simulation of very large mask layouts are conducted in parallel with reasonable turnaround time, using a Blue- Gene/L supercomputer and a Finite-Difference Time-Domain (FDTD) code developed internally within IBM. A 3-D simulation of a large 2-D layout spanning 5μm×5μm at the wafer plane (and thus (20μm×20μm×0.5μm at the mask) results in a simulation with roughly 12.5GB of memory (grid size of 10nm at the mask, single-precision computation, about 30 bytes/grid point). FDTD is flexible and easily parallelizable to enable full simulations of such large layout in approximately an hour using one BlueGene/L "midplane" containing 512 dual-processor nodes with 256MB of memory per processor. Our scaling studies on BlueGene/L demonstrate that simulations up to 100μm × 100μm at the mask can be computed in a few hours. Finally, we will show that the use of a subcell technique permits accurate simulation of features smaller than the grid discretization, thus improving on the tradeoff between computational complexity and simulation accuracy. We demonstrate the correlation of the real and quadrature components that comprise the Boundary Layer representation of the EMF behavior of a mask blank to intensity measurements of the mask diffraction patterns by an Aerial Image Measurement System (AIMS) with polarized illumination. We also discuss how this model can become a powerful tool for the assessment of the impact to the lithographic process of a mask blank.

On the effectiveness of noise masks: naturalistic vs. un-naturalistic image statistics.

PubMed

Hansen, Bruce C; Hess, Robert F

2012-05-01

It has been argued that the human visual system is optimized for identification of broadband objects embedded in stimuli possessing orientation averaged power spectra fall-offs that obey the 1/f(β) relationship typically observed in natural scene imagery (i.e., β=2.0 on logarithmic axes). Here, we were interested in whether individual spatial channels leading to recognition are functionally optimized for narrowband targets when masked by noise possessing naturalistic image statistics (β=2.0). The current study therefore explores the impact of variable β noise masks on the identification of narrowband target stimuli ranging in spatial complexity, while simultaneously controlling for physical or perceived differences between the masks. The results show that β=2.0 noise masks produce the largest identification thresholds regardless of target complexity, and thus do not seem to yield functionally optimized channel processing. The differential masking effects are discussed in the context of contrast gain control. Copyright © 2012 Elsevier Ltd. All rights reserved.

Optical performances of the FM JEM-X masks

NASA Astrophysics Data System (ADS)

Reglero, V.; Rodrigo, J.; Velasco, T.; Gasent, J. L.; Chato, R.; Alamo, J.; Suso, J.; Blay, P.; Martínez, S.; Doñate, M.; Reina, M.; Sabau, D.; Ruiz-Urien, I.; Santos, I.; Zarauz, J.; Vázquez, J.

2001-09-01

The JEM-X Signal Multiplexing Systems are large HURA codes "written" in a pure tungsten plate 0.5 mm thick. 24.247 hexagonal pixels (25% open) are spread over a total area of 535 mm diameter. The tungsten plate is embedded in a mechanical structure formed by a Ti ring, a pretensioning system (Cu-Be) and an exoskeleton structure that provides the required stiffness. The JEM-X masks differ from the SPI and IBIS masks on the absence of a code support structure covering the mask assembly. Open pixels are fully transparent to X-rays. The scope of this paper is to report the optical performances of the FM JEM-X masks defined by uncertainties on the pixel location (centroid) and size coming from the manufacturing and assembly processes. Stability of the code elements under thermoelastic deformations is also discussed. As a general statement, JEM-X Mask optical properties are nearly one order of magnitude better than specified in 1994 during the ESA instrument selection.

Analysis and modeling of photomask edge effects for 3D geometries and the effect on process window

NASA Astrophysics Data System (ADS)

Miller, Marshal A.; Neureuther, Andrew R.

2009-03-01

Simulation was used to explore boundary layer models for 1D and 2D patterns that would be appropriate for fast CAD modeling of physical effects during design. FDTD simulation was used to compare rigorous thick mask modeling to a thin mask approximation (TMA). When features are large, edges can be viewed as independent and modeled as separate from one another, but for small mask features, edges experience cross-talk. For attenuating phase-shift masks, interaction distances as large as 150nm were observed. Polarization effects are important for accurate EMF models. Due to polarization effects, the edge perturbations in line ends become different compared to a perpendicular edge. For a mask designed to be real, the 90o transmission created at edges produces an asymmetry through focus, which is also polarization dependent. Thick mask fields are calculated using TEMPEST and Panoramic Technologies software. Fields are then analyzed in the near field and on wafer CDs to examine deviations from TMA.

Modular reconfigurable matched spectral filter spectrometer

NASA Astrophysics Data System (ADS)

Schundler, Elizabeth; Engel, James R.; Gruber, Thomas; Vaillancourt, Robert; Benedict-Gill, Ryan; Mansur, David J.; Dixon, John; Potter, Kevin; Newbry, Scott

2015-06-01

OPTRA is currently developing a modular, reconfigurable matched spectral filter (RMSF) spectrometer for the monitoring of greenhouse gases. The heart of this spectrometer will be the RMSF core, which is a dispersive spectrometer that images the sample spectrum from 2000 - 3333 cm-1 onto a digital micro-mirror device (DMD) such that different columns correspond to different wavebands. By applying masks to this DMD, a matched spectral filter can be applied in hardware. The core can then be paired with different fore-optics or detector modules to achieve active in situ or passive remote detection of the chemicals of interest. This results in a highly flexible system that can address a wide variety of chemicals by updating the DMD masks and a wide variety of applications by swapping out fore-optic and detector modules. In either configuration, the signal on the detector is effectively a dot-product between the applied mask and the sample spectrum that can be used to make detection and quantification determinations. Using this approach significantly reduces the required data bandwidth of the sensor without reducing the information content, therefore making it ideal for remote, unattended systems. This paper will focus on the design of the RMSF core.

The lithographer's dilemma: shrinking without breaking the bank

NASA Astrophysics Data System (ADS)

Levinson, Harry J.

2013-10-01

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

Uniformity Masks Design Method Based on the Shadow Matrix for Coating Materials with Different Condensation Characteristics

PubMed Central

2013-01-01

An intuitionistic method is proposed to design shadow masks to achieve thickness profile control for evaporation coating processes. The proposed method is based on the concept of the shadow matrix, which is a matrix that contains coefficients that build quantitive relations between shape parameters of masks and shadow quantities of substrate directly. By using the shadow matrix, shape parameters of shadow masks could be derived simply by solving a matrix equation. Verification experiments were performed on a special case where coating materials have different condensation characteristics. By using the designed mask pair with complementary shapes, thickness uniformities of better than 98% are demonstrated for MgF2 (m = 1) and LaF3 (m = 0.5) simultaneously on a 280 mm diameter spherical substrate with the radius curvature of 200 mm. PMID:24227996

A Parallel Vector Machine for the PM Programming Language

NASA Astrophysics Data System (ADS)

Bellerby, Tim

2016-04-01

PM is a new programming language which aims to make the writing of computational geoscience models on parallel hardware accessible to scientists who are not themselves expert parallel programmers. It is based around the concept of communicating operators: language constructs that enable variables local to a single invocation of a parallelised loop to be viewed as if they were arrays spanning the entire loop domain. This mechanism enables different loop invocations (which may or may not be executing on different processors) to exchange information in a manner that extends the successful Communicating Sequential Processes idiom from single messages to collective communication. Communicating operators avoid the additional synchronisation mechanisms, such as atomic variables, required when programming using the Partitioned Global Address Space (PGAS) paradigm. Using a single loop invocation as the fundamental unit of concurrency enables PM to uniformly represent different levels of parallelism from vector operations through shared memory systems to distributed grids. This paper describes an implementation of PM based on a vectorised virtual machine. On a single processor node, concurrent operations are implemented using masked vector operations. Virtual machine instructions operate on vectors of values and may be unmasked, masked using a Boolean field, or masked using an array of active vector cell locations. Conditional structures (such as if-then-else or while statement implementations) calculate and apply masks to the operations they control. A shift in mask representation from Boolean to location-list occurs when active locations become sufficiently sparse. Parallel loops unfold data structures (or vectors of data structures for nested loops) into vectors of values that may additionally be distributed over multiple computational nodes and then split into micro-threads compatible with the size of the local cache. Inter-node communication is accomplished using standard OpenMP and MPI. Performance analyses of the PM vector machine, demonstrating its scaling properties with respect to domain size and the number of processor nodes will be presented for a range of hardware configurations. The PM software and language definition are being made available under unrestrictive MIT and Creative Commons Attribution licenses respectively: www.pm-lang.org.

Bayesian cloud detection for MERIS, AATSR, and their combination

NASA Astrophysics Data System (ADS)

Hollstein, A.; Fischer, J.; Carbajal Henken, C.; Preusker, R.

2014-11-01

A broad range of different of Bayesian cloud detection schemes is applied to measurements from the Medium Resolution Imaging Spectrometer (MERIS), the Advanced Along-Track Scanning Radiometer (AATSR), and their combination. The cloud masks were designed to be numerically efficient and suited for the processing of large amounts of data. Results from the classical and naive approach to Bayesian cloud masking are discussed for MERIS and AATSR as well as for their combination. A sensitivity study on the resolution of multidimensional histograms, which were post-processed by Gaussian smoothing, shows how theoretically insufficient amounts of truth data can be used to set up accurate classical Bayesian cloud masks. Sets of exploited features from single and derived channels are numerically optimized and results for naive and classical Bayesian cloud masks are presented. The application of the Bayesian approach is discussed in terms of reproducing existing algorithms, enhancing existing algorithms, increasing the robustness of existing algorithms, and on setting up new classification schemes based on manually classified scenes.

Susceptibility weighted imaging: differentiating between calcification and hemosiderin*

PubMed Central

Barbosa, Jeam Haroldo Oliveira; Santos, Antonio Carlos; Salmon, Carlos Ernesto Garrido

2015-01-01

Objective To present a detailed explanation on the processing of magnetic susceptibility weighted imaging (SWI), demonstrating the effects of echo time and sensitive mask on the differentiation between calcification and hemosiderin. Materials and Methods Computed tomography and magnetic resonance (magnitude and phase) images of six patients (age range 41– 54 years; four men) were retrospectively selected. The SWI images processing was performed using the Matlab’s own routine. Results Four out of the six patients showed calcifications at computed tomography images and their SWI images demonstrated hyperintense signal at the calcification regions. The other patients did not show any calcifications at computed tomography, and SWI revealed the presence of hemosiderin deposits with hypointense signal. Conclusion The selection of echo time and of the mask may change all the information on SWI images, and compromise the diagnostic reliability. Amongst the possible masks, the authors highlight that the sigmoid mask allows for contrasting calcifications and hemosiderin on a single SWI image. PMID:25987750

The temporal dynamics of masked repetition picture priming effects: manipulations of stimulus-onset asynchrony (SOA) and prime duration.

PubMed

Eddy, Marianna D; Holcomb, Phillip J

2010-06-22

The current study used event-related potentials (ERPs) and masked repetition priming to examine the time-course of picture processing. We manipulated the stimulus-onset asynchrony (110 ms, 230 ms, 350 ms, and 470 ms) between repeated and unrepeated prime-target pairs while holding the prime duration constant (50 ms) (Experiment 1) as well as the prime durations (30 ms, 50 ms, 70 ms, and 90 ms) (Experiment 2) with a constant SOA of 110 ms in a masked repetition priming paradigm with pictures. The aim of this study was to further elucidate the mechanisms underlying previously observed ERP components in masked priming with pictures. We found that both the N/P190 and N400 are modulated by changes in prime duration and SOA, however, it appears that longer prime exposure rather than a longer SOA leads to more in-depth processing as indexed by larger N400 effects. (c) 2010 Elsevier B.V. All rights reserved.

Comparison of OPC job prioritization schemes to generate data for mask manufacturing

NASA Astrophysics Data System (ADS)

Lewis, Travis; Veeraraghavan, Vijay; Jantzen, Kenneth; Kim, Stephen; Park, Minyoung; Russell, Gordon; Simmons, Mark

2015-03-01

Delivering mask ready OPC corrected data to the mask shop on-time is critical for a foundry to meet the cycle time commitment for a new product. With current OPC compute resource sharing technology, different job scheduling algorithms are possible, such as, priority based resource allocation and fair share resource allocation. In order to maximize computer cluster efficiency, minimize the cost of the data processing and deliver data on schedule, the trade-offs of each scheduling algorithm need to be understood. Using actual production jobs, each of the scheduling algorithms will be tested in a production tape-out environment. Each scheduling algorithm will be judged on its ability to deliver data on schedule and the trade-offs associated with each method will be analyzed. It is now possible to introduce advance scheduling algorithms to the OPC data processing environment to meet the goals of on-time delivery of mask ready OPC data while maximizing efficiency and reducing cost.

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

NASA Astrophysics Data System (ADS)

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

2008-05-01

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

MANN: A program to transfer designs for diffractive optical elements to a MANN photolithographic mask generator

NASA Technical Reports Server (NTRS)

Matthys, Donald R.

1994-01-01

There are two basic areas of interest for diffractive optics. In the first, the property of wavefront division is exploited for achieving optical fanout, analogous to the more familiar electrical fanout of electronic circuitry. The basic problem here is that when using a simple uniform diffraction grating the energy input is divided unevenly among the output beams. The other area of interest is the use of diffractive elements to replace or supplement standard refractive elements such as lenses. Again, local grating variations can be used to control the amount of bending imparted to optical rays, and the efficiency of the diffractive element will depend on how closely the element can be matched to the design requirements. In general, production restrictions limit how closely the element approaches the design, and for the common case of photolithographic production, a series of binary masks is required to achieve high efficiency. The actual design process is much more involved than in the case of elements for optical fanout, as the desired phase of the optical wavefront over some reference plane must be specified and the phase alteration to be introduced at each point by the diffraction element must be known. This generally requires the utilization of a standard optical design program. Two approaches are possible. In the first approach, the diffractive element is treated as a special type of lens and the ordinary optical design equations are used. Optical design programs tend to follow a second approach, namely, using the equations of optical interference derived from holographic theory and then allowing the introduction of phase front corrections in the form of polynomial equations. By using either of these two methods, diffractive elements can be used not only to compensate for distortions such as chromatic or spherical aberration, but also to perform the work of a variety of other optical elements such as null correctors, beam shapers, etc. The main focus of the project described in this report is how the design information from the lens design program is incorporated into the photolithographic process. It is shown that the MANN program, a photolithographic mask generator, fills the need for a link between lens design programs and mask generation controllers.The generated masks can be used to expose a resist-coated substrate which is etched and then must be re-coated, re-exposed, and re-etched for making copies, just as in the electronics industry.

Edge enhancement and image equalization by unsharp masking using self-adaptive photochromic filters.

PubMed

Ferrari, José A; Flores, Jorge L; Perciante, César D; Frins, Erna

2009-07-01

A new method for real-time edge enhancement and image equalization using photochromic filters is presented. The reversible self-adaptive capacity of photochromic materials is used for creating an unsharp mask of the original image. This unsharp mask produces a kind of self filtering of the original image. Unlike the usual Fourier (coherent) image processing, the technique we propose can also be used with incoherent illumination. Validation experiments with Bacteriorhodopsin and photochromic glass are presented.

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

NASA Astrophysics Data System (ADS)

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

2011-11-01

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

Influence of Temporal Expectations on Response Priming by Subliminal Faces

PubMed Central

Guex, Raphael; Vuilleumier, Patrik

2016-01-01

Unconscious processes are often assumed immune from attention influence. Recent behavioral studies suggest however that the processing of subliminal information can be influenced by temporal attention. To examine the neural mechanisms underlying these effects, we used a stringent masking paradigm together with fMRI to investigate how temporal attention modulates the processing of unseen (masked) faces. Participants performed a gender decision task on a visible neutral target face, preceded by a masked prime face that could vary in gender (same or different than target) and emotion expression (neutral or fearful). We manipulated temporal attention by instructing participants to expect targets to appear either early or late during the stimulus sequence. Orienting temporal attention to subliminal primes influenced response priming by masked faces, even when gender was incongruent. In addition, gender-congruent primes facilitated responses regardless of attention while gender-incongruent primes reduced accuracy when attended. Emotion produced no differential effects. At the neural level, incongruent and temporally unexpected primes increased brain response in regions of the fronto-parietal attention network, reflecting greater recruitment of executive control and reorienting processes. Congruent and expected primes produced higher activations in fusiform cortex, presumably reflecting facilitation of perceptual processing. These results indicate that temporal attention can influence subliminal processing of face features, and thus facilitate information integration according to task-relevance regardless of conscious awareness. They also suggest that task-congruent information between prime and target may facilitate response priming even when temporal attention is not selectively oriented to the prime onset time. PMID:27764124

Influence of Temporal Expectations on Response Priming by Subliminal Faces.

PubMed

Pichon, Swann; Guex, Raphael; Vuilleumier, Patrik

2016-01-01

Unconscious processes are often assumed immune from attention influence. Recent behavioral studies suggest however that the processing of subliminal information can be influenced by temporal attention. To examine the neural mechanisms underlying these effects, we used a stringent masking paradigm together with fMRI to investigate how temporal attention modulates the processing of unseen (masked) faces. Participants performed a gender decision task on a visible neutral target face, preceded by a masked prime face that could vary in gender (same or different than target) and emotion expression (neutral or fearful). We manipulated temporal attention by instructing participants to expect targets to appear either early or late during the stimulus sequence. Orienting temporal attention to subliminal primes influenced response priming by masked faces, even when gender was incongruent. In addition, gender-congruent primes facilitated responses regardless of attention while gender-incongruent primes reduced accuracy when attended. Emotion produced no differential effects. At the neural level, incongruent and temporally unexpected primes increased brain response in regions of the fronto-parietal attention network, reflecting greater recruitment of executive control and reorienting processes. Congruent and expected primes produced higher activations in fusiform cortex, presumably reflecting facilitation of perceptual processing. These results indicate that temporal attention can influence subliminal processing of face features, and thus facilitate information integration according to task-relevance regardless of conscious awareness. They also suggest that task-congruent information between prime and target may facilitate response priming even when temporal attention is not selectively oriented to the prime onset time.

Simultaneous masking additivity for short Gaussian-shaped tones: spectral effects.

PubMed

Laback, Bernhard; Necciari, Thibaud; Balazs, Peter; Savel, Sophie; Ystad, Sølvi

2013-08-01

Laback et al. [(2011). J. Acoust. Soc. Am. 129, 888-897] investigated the additivity of nonsimultaneous masking using short Gaussian-shaped tones as maskers and target. The present study involved Gaussian stimuli to measure the additivity of simultaneous masking for combinations of up to four spectrally separated maskers. According to most basilar membrane measurements, the maskers should be processed linearly at the characteristic frequency (CF) of the target. Assuming also compression of the target, all masker combinations should produce excess masking (exceeding linear additivity). The results for a pair of maskers flanking the target indeed showed excess masking. The amount of excess masking could be predicted by a model assuming summation of masker-evoked excitations in intensity units at the target CF and compression of the target, using compressive input/output functions derived from the nonsimultaneous masking study. However, the combinations of lower-frequency maskers showed much less excess masking than predicted by the model. This cannot easily be attributed to factors like off-frequency listening, combination tone perception, or between-masker suppression. It was better predicted, however, by assuming weighted intensity summation of masker excitations. The optimum weights for the lower-frequency maskers were smaller than one, consistent with partial masker compression as indicated by recent psychoacoustic data.

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.

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.

Electrochemical Micromachining with Fiber Laser Masking for 304 Stainless Steel

NASA Astrophysics Data System (ADS)

Li, Xiaohai; Wang, Shuming; Wang, Dong; Tong, Han

2017-10-01

In order to fabricate micro structure, the combined machining of electrochemical micro machining (EMM) and laser masking for 304 stainless steel was studied. A device of composite machining of EMM with laser masking was developed, and the experiments of EMM with laser masking were carried out. First, by marking pattern with fiber laser on the surface of 304 stainless steel, the special masking layer can be formed. Through X ray photoelectron spectroscopy (XPS), the corrosion resistance of laser masking layer was analyzed. It is proved by XPS that the iron oxide and chromium oxide on the surface of stainless steel generates due to air oxidation when laser scanning heats. Second, the localization and precision of EMM are improved, since the marking patterns forming on the surface of stainless steel by laser masking play a protective role in the process of subsequent EMM when the appropriate parameters of EMM are selected. At last, the shape and the roughness of the machined samples were measured by SEM and optical profilometer and analyzed. The results show that the rapid fabrication of micro structures on the 304 stainless steel surface can be achieved by EMM with fiber laser masking, which has a good prospect in the field of micro machining.

Recognition of speech in noise after application of time-frequency masks: Dependence on frequency and threshold parameters

PubMed Central

Sinex, Donal G.

2013-01-01

Binary time-frequency (TF) masks can be applied to separate speech from noise. Previous studies have shown that with appropriate parameters, ideal TF masks can extract highly intelligible speech even at very low speech-to-noise ratios (SNRs). Two psychophysical experiments provided additional information about the dependence of intelligibility on the frequency resolution and threshold criteria that define the ideal TF mask. Listeners identified AzBio Sentences in noise, before and after application of TF masks. Masks generated with 8 or 16 frequency bands per octave supported nearly-perfect identification. Word recognition accuracy was slightly lower and more variable with 4 bands per octave. When TF masks were generated with a local threshold criterion of 0 dB SNR, the mean speech reception threshold was −9.5 dB SNR, compared to −5.7 dB for unprocessed sentences in noise. Speech reception thresholds decreased by about 1 dB per dB of additional decrease in the local threshold criterion. Information reported here about the dependence of speech intelligibility on frequency and level parameters has relevance for the development of non-ideal TF masks for clinical applications such as speech processing for hearing aids. PMID:23556604

The impact of perilaryngeal vibration on the self-perception of loudness and the Lombard effect.

PubMed

Brajot, François-Xavier; Nguyen, Don; DiGiovanni, Jeffrey; Gracco, Vincent L

2018-04-05

The role of somatosensory feedback in speech and the perception of loudness was assessed in adults without speech or hearing disorders. Participants completed two tasks: loudness magnitude estimation of a short vowel and oral reading of a standard passage. Both tasks were carried out in each of three conditions: no-masking, auditory masking alone, and mixed auditory masking plus vibration of the perilaryngeal area. A Lombard effect was elicited in both masking conditions: speakers unconsciously increased vocal intensity. Perilaryngeal vibration further increased vocal intensity above what was observed for auditory masking alone. Both masking conditions affected fundamental frequency and the first formant frequency as well, but only vibration was associated with a significant change in the second formant frequency. An additional analysis of pure-tone thresholds found no difference in auditory thresholds between masking conditions. Taken together, these findings indicate that perilaryngeal vibration effectively masked somatosensory feedback, resulting in an enhanced Lombard effect (increased vocal intensity) that did not alter speakers' self-perception of loudness. This implies that the Lombard effect results from a general sensorimotor process, rather than from a specific audio-vocal mechanism, and that the conscious self-monitoring of speech intensity is not directly based on either auditory or somatosensory feedback.

Ringfield lithographic camera

DOEpatents

Sweatt, W.C.

1998-09-08

A projection lithography camera is presented with a wide ringfield optimized so as to make efficient use of extreme ultraviolet radiation from a large area radiation source (e.g., D{sub source} {approx_equal} 0.5 mm). The camera comprises four aspheric mirrors optically arranged on a common axis of symmetry. The camera includes an aperture stop that is accessible through a plurality of partial aperture stops to synthesize the theoretical aperture stop. Radiation from a mask is focused to form a reduced image on a wafer, relative to the mask, by reflection from the four aspheric mirrors. 11 figs.

Method of making low leakage N-channel SOS transistors utilizing positive photoresist masking techniques

NASA Technical Reports Server (NTRS)

Policastro, Steven G. (Inventor); Woo, Dae-Shik (Inventor)

1983-01-01

A self-aligned method of implanting the edges of NMOS/SOS transistors is described. The method entails covering the silicon islands with a thick oxide layer, applying a protective photoresist layer over the thick oxide layer, and exposing the photoresist layer from the underside of the sapphire substrate thereby using the island as an exposure mask. Only the photoresist on the islands' edges will be exposed. The exposed photoresist is then removed and the thick oxide is removed from the islands edges which are then implanted.

Automatic emotion processing as a function of trait emotional awareness: an fMRI study

PubMed Central

Lichev, Vladimir; Sacher, Julia; Ihme, Klas; Rosenberg, Nicole; Quirin, Markus; Lepsien, Jöran; Pampel, André; Rufer, Michael; Grabe, Hans-Jörgen; Kugel, Harald; Kersting, Anette; Villringer, Arno; Lane, Richard D.

2015-01-01

It is unclear whether reflective awareness of emotions is related to extent and intensity of implicit affective reactions. This study is the first to investigate automatic brain reactivity to emotional stimuli as a function of trait emotional awareness. To assess emotional awareness the Levels of Emotional Awareness Scale (LEAS) was administered. During scanning, masked happy, angry, fearful and neutral facial expressions were presented to 46 healthy subjects, who had to rate the fit between artificial and emotional words. The rating procedure allowed assessment of shifts in implicit affectivity due to emotion faces. Trait emotional awareness was associated with increased activation in the primary somatosensory cortex, inferior parietal lobule, anterior cingulate gyrus, middle frontal and cerebellar areas, thalamus, putamen and amygdala in response to masked happy faces. LEAS correlated positively with shifts in implicit affect caused by masked happy faces. According to our findings, people with high emotional awareness show stronger affective reactivity and more activation in brain areas involved in emotion processing and simulation during the perception of masked happy facial expression than people with low emotional awareness. High emotional awareness appears to be characterized by an enhanced positive affective resonance to others at an automatic processing level. PMID:25140051

The effect of integration masking on visual processing in perceptual categorization.

PubMed

Hélie, Sébastien

2017-08-01

Learning to recognize and categorize objects is an essential cognitive skill allowing animals to function in the world. However, animals rarely have access to a canonical view of an object in an uncluttered environment. Hence, it is essential to study categorization under noisy, degraded conditions. In this article, we explore how the brain processes categorization stimuli in low signal-to-noise conditions using multivariate pattern analysis. We used an integration masking paradigm with mask opacity of 50%, 60%, and 70% inside a magnetic resonance imaging scanner. The results show that mask opacity affects blood-oxygen-level dependent (BOLD) signal in visual processing areas (V1, V2, V3, and V4) but does not affect the BOLD signal in brain areas traditionally associated with categorization (prefrontal cortex, striatum, hippocampus). This suggests that when a stimulus is difficult to extract from its background (e.g., low signal-to-noise ratio), the visual system extracts the stimulus and that activity in areas typically associated with categorization are not affected by the difficulty level of the visual conditions. We conclude with implications of this result for research on visual attention, categorization, and the integration of these fields. Copyright © 2017 Elsevier Inc. All rights reserved.

Dissociable brain mechanisms underlying the conscious and unconscious control of behavior.

PubMed

van Gaal, Simon; Lamme, Victor A F; Fahrenfort, Johannes J; Ridderinkhof, K Richard

2011-01-01

Cognitive control allows humans to overrule and inhibit habitual responses to optimize performance in challenging situations. Contradicting traditional views, recent studies suggest that cognitive control processes can be initiated unconsciously. To further capture the relation between consciousness and cognitive control, we studied the dynamics of inhibitory control processes when triggered consciously versus unconsciously in a modified version of the stop task. Attempts to inhibit an imminent response were often successful after unmasked (visible) stop signals. Masked (invisible) stop signals rarely succeeded in instigating overt inhibition but did trigger slowing down of response times. Masked stop signals elicited a sequence of distinct ERP components that were also observed on unmasked stop signals. The N2 component correlated with the efficiency of inhibitory control when elicited by unmasked stop signals and with the magnitude of slowdown when elicited by masked stop signals. Thus, the N2 likely reflects the initiation of inhibitory control, irrespective of conscious awareness. The P3 component was much reduced in amplitude and duration on masked versus unmasked stop trials. These patterns of differences and similarities between conscious and unconscious cognitive control processes are discussed in a framework that differentiates between feedforward and feedback connections in yielding conscious experience.

Performance of the ALTA 3500 scanned-laser mask lithography system

NASA Astrophysics Data System (ADS)

Buck, Peter D.; Buxbaum, Alex H.; Coleman, Thomas P.; Tran, Long

1998-09-01

The ALTA 3500, an advanced scanned-laser mask lithography tool produced by Etec, was introduced to the marketplace in September 1997. The system architecture was described and an initial performance evaluation was presented. This system, based on the ALTA 3000, uses a new 33.3X, 0.8 NA final reduction lens to reduce the spot size to 0.27 micrometers FWHM, thereby affording improved resolution and pattern acuity on the mask. To take advantage of the improved resolution, a new anisotropic chrome etch process has been developed and introduced along with change from Olin 895i resist to TOK iP3600 resist. In this paper we will more extensively describe the performance of the ALTA 3500 and the performance of these new processes.

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

NASA Astrophysics Data System (ADS)

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

2013-09-01

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

Effects of set-size and lateral masking in visual search.

PubMed

Põder, Endel

2004-01-01

In the present research, the roles of lateral masking and central processing limitations in visual search were studied. Two search conditions were used: (1) target differed from distractors by presence/absence of a simple feature; (2) target differed by relative position of the same components only. The number of displayed stimuli (set-size) and the distance between neighbouring stimuli were varied as independently as possible in order to measure the effect of both. The effect of distance between stimuli (lateral masking) was found to be similar in both conditions. The effect of set-size was much larger for relative position stimuli. The results support the view that perception of relative position of stimulus components is limited mainly by the capacity of central processing.

A study of an alignment-less lithography method as an educational resource

NASA Astrophysics Data System (ADS)

Kai, Kazuho; Shiota, Koki; Nagaoka, Shiro; Mahmood, Mohamad Rusop Bin Haji; Kawai, Akira

2016-07-01

A simplification of the lithography process was studied. The simplification method of photolithography, named "alignment-less lithography" was proposed by omitting the photomask alignment process in photolithography process using mechanically aligned photomasks and substrate by using a simple jig on which countersinks were formed. Photomasks made of glass and the photomasks made of transparent plastic sheets were prepared for the process. As the result, approximately 5µm in the case of the glass mask, and 20µm in the case of the OHP mask were obtained with repetitive accuracies, respectively. It was confirmed that the alignment-less lithography method was successful. The possibility of the application to an educational program, such as a heuristic for solving problems was suggested using the method with the OHP mask. The nMOS FET fabrication process was successfully demonstrated using this method. The feasibility of this process was confirmed. It is expected that a totally simplified device fabrication process can be achievable when combined with other simplifications, such ass the simplified impurity diffusion processes using PSG and BSG thin film as diffusion source prepared by the Sol-Gel material under normal air environment.

Design and performance of a production-worthy excimer-laser-based stepper

NASA Astrophysics Data System (ADS)

Unger, Robert; Sparkes, Christopher; Disessa, Peter A.; Elliott, David J.

1992-06-01

Excimer-laser-based steppers have matured to a production-worthy state. Widefield high-NA lenses have been developed and characterized for imaging down to 0.35 micron and below. Excimer lasers have attained practical levels of performance capability and stability, reliability, safety, and operating cost. Excimer stepper system integration and control issues such as focus, exposure, and overlay stability have been addressed. Enabling support technologies -- resist systems, resist processing, metrology and conventional mask making -- continue to progress and are becoming available. This paper discusses specific excimer stepper design challenges, and presents characterization data from several field installations of XLSTM deep-UV steppers configured with an advanced lens design.

Parallel Implementation of the Terrain Masking Algorithm

DTIC Science & Technology

1994-03-01

contains behavior rules which can define a computation or an algorithm. It can communicate with other process nodes, it can contain local data, and it can...terrain maskirg calculation is being performed. It is this algorithm that comsumes about seventy percent of the total terrain masking calculation time

ProTEK PSB as Biotechnology Photosensitive Protection Mask on 3C-SiC-on-Si in MEMS Sensor

NASA Astrophysics Data System (ADS)

Marsi, N.; Majlis, B. Y.; Mohd-Yasin, F.; Hamzah, A. A.; Mohd Rus, A. Z.

2016-11-01

This project presents the fabrication of MEMS employing a cubic silicon carbide (3C- SiC) on silicon wafer using newly developed ProTEK PSB as biotechnology photosensitive protection mask. This new biotechnology can reduce the number of processes and simplify the process flow with minimal impact on overall undercut performance. The 680 pm thick wafer is back-etched, leaving the 3C-SiC thin film with a thickness of 1.0 μm as the flexible diaphragm to detect pressure. The effect of the new coating of ProTEK PSB on different KOH solvents were investigated depending on various factors such as development time, final cure temperature and the thickness of the ProTEK PSB deposited layer. It is found that 6.174 μm thickness of ProTEK PSB offers some possibility of reducing the processing time compared to silicon nitride etch masks in KOH (55%wt, 80°C). The new ProTEK PSB biotechnology photosensitive protection mask indicates good stability and sustains its performance in different treatments under KOH and IPA for 8 hours. This work also revealed that the fabrication of MEMS sensors using the new biotechnology photosensitive protection mask provides a simple assembly approach and reduces manufacturing costs. The MEMS sensor can operate up to 500 °C as indicated under the sensitivity of 0.826 pF/MPa with nonlinearity and hysteresis of 0.61% and 3.13%, respectively.

Achieving mask order processing automation, interoperability and standardization based on P10

NASA Astrophysics Data System (ADS)

Rodriguez, B.; Filies, O.; Sadran, D.; Tissier, Michel; Albin, D.; Stavroulakis, S.; Voyiatzis, E.

2007-02-01

Last year the MUSCLE (Masks through User's Supply Chain: Leadership by Excellence) project was presented. Here is the project advancement. A key process in mask supply chain management is the exchange of technical information for ordering masks. This process is large, complex, company specific and error prone, and leads to longer cycle times and higher costs due to missing or wrong inputs. Its automation and standardization could produce significant benefits. We need to agree on the standard for mandatory and optional parameters, and also a common way to describe parameters when ordering. A system was created to improve the performance in terms of Key Performance Indicators (KPIs) such as cycle time and cost of production. This tool allows us to evaluate and measure the effect of factors, as well as the effect of implementing the improvements of the complete project. Next, a benchmark study and a gap analysis were performed. These studies show the feasibility of standardization, as there is a large overlap in requirements. We see that the SEMI P10 standard needs enhancements. A format supporting the standard is required, and XML offers the ability to describe P10 in a flexible way. Beyond using XML for P10, the semantics of the mask order should also be addressed. A system design and requirements for a reference implementation for a P10 based management system are presented, covering a mechanism for the evolution and for version management and a design for P10 editing and data validation.

Spontaneous Gender Categorization in Masking and Priming Studies: Key for Distinguishing Jane from John Doe but Not Madonna from Sinatra

PubMed Central

Habibi, Ruth; Khurana, Beena

2012-01-01

Facial recognition is key to social interaction, however with unfamiliar faces only generic information, in the form of facial stereotypes such as gender and age is available. Therefore is generic information more prominent in unfamiliar versus familiar face processing? In order to address the question we tapped into two relatively disparate stages of face processing. At the early stages of encoding, we employed perceptual masking to reveal that only perception of unfamiliar face targets is affected by the gender of the facial masks. At the semantic end; using a priming paradigm, we found that while to-be-ignored unfamiliar faces prime lexical decisions to gender congruent stereotypic words, familiar faces do not. Our findings indicate that gender is a more salient dimension in unfamiliar relative to familiar face processing, both in early perceptual stages as well as later semantic stages of person construal. PMID:22389697

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.

Rapid mask prototyping for microfluidics

PubMed Central

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

2016-01-01

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. PMID:27014396

Spatial frequency filtered images reveal differences between masked and unmasked processing of emotional information.

PubMed

Rohr, Michaela; Wentura, Dirk

2014-10-01

High and low spatial frequency information has been shown to contribute differently to the processing of emotional information. In three priming studies using spatial frequency filtered emotional face primes, emotional face targets, and an emotion categorization task, we investigated this issue further. Differences in the pattern of results between short and masked, and short and long unmasked presentation conditions emerged. Given long and unmasked prime presentation, high and low frequency primes triggered emotion-specific priming effects. Given brief and masked prime presentation in Experiment 2, we found a dissociation: High frequency primes caused a valence priming effect, whereas low frequency primes yielded a differentiation between low and high arousing information within the negative domain. Brief and unmasked prime presentation in Experiment 3 revealed that subliminal processing of primes was responsible for the pattern observed in Experiment 2. The implications of these findings for theories of early emotional information processing are discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

Nonconscious semantic processing of emotional words modulates conscious access

PubMed Central

Gaillard, Raphaël; Del Cul, Antoine; Naccache, Lionel; Vinckier, Fabien; Cohen, Laurent; Dehaene, Stanislas

2006-01-01

Whether masked words can be processed at a semantic level remains a controversial issue in cognitive psychology. Although recent behavioral studies have demonstrated masked semantic priming for number words, attempts to generalize this finding to other categories of words have failed. Here, as an alternative to subliminal priming, we introduce a sensitive behavioral method to detect nonconscious semantic processing of words. The logic of this method consists of presenting words close to the threshold for conscious perception and examining whether their semantic content modulates performance in objective and subjective tasks. Our results disclose two independent sources of modulation of the threshold for access to consciousness. First, prior conscious perception of words increases the detection rate of the same words when they are subsequently presented with stronger masking. Second, the threshold for conscious access is lower for emotional words than for neutral ones, even for words that have not been previously consciously perceived, thus implying that written words can receive nonconscious semantic processing. PMID:16648261

The development of sentence interpretation: effects of perceptual, attentional and semantic interference.

PubMed

Leech, Robert; Aydelott, Jennifer; Symons, Germaine; Carnevale, Julia; Dick, Frederic

2007-11-01

How does the development and consolidation of perceptual, attentional, and higher cognitive abilities interact with language acquisition and processing? We explored children's (ages 5-17) and adults' (ages 18-51) comprehension of morphosyntactically varied sentences under several competing speech conditions that varied in the degree of attentional demands, auditory masking, and semantic interference. We also evaluated the relationship between subjects' syntactic comprehension and their word reading efficiency and general 'speed of processing'. We found that the interactions between perceptual and attentional processes and complex sentence interpretation changed considerably over the course of development. Perceptual masking of the speech signal had an early and lasting impact on comprehension, particularly for more complex sentence structures. In contrast, increased attentional demand in the absence of energetic auditory masking primarily affected younger children's comprehension of difficult sentence types. Finally, the predictability of syntactic comprehension abilities by external measures of development and expertise is contingent upon the perceptual, attentional, and semantic milieu in which language processing takes place.

A blind source separation approach for humpback whale song separation.

PubMed

Zhang, Zhenbin; White, Paul R

2017-04-01

Many marine mammal species are highly social and are frequently encountered in groups or aggregations. When conducting passive acoustic monitoring in such circumstances, recordings commonly contain vocalizations of multiple individuals which overlap in time and frequency. This paper considers the use of blind source separation as a method for processing these recordings to separate the calls of individuals. The example problem considered here is that of the songs of humpback whales. The high levels of noise and long impulse responses can make source separation in underwater contexts a challenging proposition. The approach present here is based on time-frequency masking, allied to a noise reduction process. The technique is assessed using simulated and measured data sets, and the results demonstrate the effectiveness of the method for separating humpback whale songs.

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.

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.

Masked translation priming effects with low proficient bilinguals.

PubMed

Dimitropoulou, Maria; Duñabeitia, Jon Andoni; Carreiras, Manuel

2011-02-01

Non-cognate masked translation priming lexical decision studies with unbalanced bilinguals suggest that masked translation priming effects are asymmetric as a function of the translation direction (significant effects only in the dominant [L1] to nondominant [L2] language translation direction). However, in contrast to the predictions of most current accounts of masked translation priming effects, bidirectional effects have recently been reported with a group of low proficient bilinguals Duyck & Warlop 2009 (Experimental Psychology 56:173-179). In a series of masked translation priming lexical decision experiments we examined whether the same pattern of effects would emerge with late and low proficient Greek (L1)-Spanish (L2) bilinguals. Contrary to the results obtained by Duyck and Warlop, and in line with the results found in most studies in the masked priming literature, significant translation priming effects emerged only when the bilinguals performed the task with L1 primes and L2 targets. The existence of the masked translation priming asymmetry with low proficient bilinguals suggests that cross-linguistic automatic lexico-semantic links may be established very early in the process of L2 acquisition. These findings could help to define models of bilingualism that consider L2 proficiency level to be a determining factor.

An in-vitro-in-vivo taste assessment of bitter drug: comparative electronic tongues study.

PubMed

Maniruzzaman, Mohammed; Douroumis, Dennis

2015-01-01

The efficiency of the Astree e-tongue and Taste Sensing system TS5000Z for the evaluation of the taste masking effect of hot melt extruded formulations was investigated in this study. Hot melt extrusion (HME) processing was optimized using Randcastle single screw extruder (USA) to manufacture extrudates with desirable characteristics. Cationic model drug propranolol HCl (PRP) was processed with the anionic polymers - Eudragit L100 (L100) and Eudragit L100-55 (Acryl-EZE). Solid state of the drug in polymer matrices was evaluated by scanning electron microscopy (SEM), differential scanning calorimetry, particle size analysis, Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) analysis. In-vitro taste masking efficiency of the two polymers was performed by using two different e-tongues (Astree e-tongue and TS5000Z). The results obtained from both e-tongues were further compared and contrast to find out the sensor outputs in all formulations. Solid state analysis of the extruded formulations revealed the presence of amorphous PRP. Both e-tongues were able to detect the taste masking variations of the extrudates and were in good agreement with the in-vivo results obtained from a panel of six healthy human volunteers (R(2)  > 0.84). However, each e-tongue sensor demonstrated different sensitivity, suggesting a careful consideration of the experimental findings during melt extrusion, is necessary for the development of taste-masked formulations. Furthermore, FTIR spectroscopy and NMR studies revealed possible drug polymer intermolecular interactions as the mechanism of successful taste masking. HME can effectively be used to manufacture taste-masked extruded formulations, while both e-tongues demonstrated satisfactory taste analysis for the development of taste-masked formulations. © 2014 Royal Pharmaceutical Society.

Anatomic and physiopathologic changes affecting the airway of the elderly patient: implications for geriatric-focused airway management

PubMed Central

Johnson, Kathleen N; Botros, Daniel B; Groban, Leanne; Bryan, Yvon F

2015-01-01

There are many anatomical, physiopathological, and cognitive changes that occur in the elderly that affect different components of airway management: intubation, ventilation, oxygenation, and risk of aspiration. Anatomical changes occur in different areas of the airway from the oral cavity to the larynx. Common changes to the airway include tooth decay, oropharyngeal tumors, and significant decreases in neck range of motion. These changes may make intubation challenging by making it difficult to visualize the vocal cords and/or place the endotracheal tube. Also, some of these changes, including but not limited to, atrophy of the muscles around the lips and an edentulous mouth, affect bag mask ventilation due to a difficult face-mask seal. Physiopathologic changes may impact airway management as well. Common pulmonary issues in the elderly (eg, obstructive sleep apnea and COPD) increase the risk of an oxygen desaturation event, while gastrointestinal issues (eg, achalasia and gastroesophageal reflux disease) increase the risk of aspiration. Finally, cognitive changes (eg, dementia) not often seen as related to airway management may affect patient cooperation, especially if an awake intubation is required. Overall, degradation of the airway along with other physiopathologic and cognitive changes makes the elderly population more prone to complications related to airway management. When deciding which airway devices and techniques to use for intubation, the clinician should also consider the difficulty associated with ventilating the patient, the patient’s risk of oxygen desaturation, and/or aspiration. For patients who may be difficult to bag mask ventilate or who have a risk of aspiration, a specialized supralaryngeal device may be preferable over bag mask for ventilation. Patients with tumors or decreased neck range of motion may require a device with more finesse and maneuverability, such as a flexible fiberoptic broncho-scope. Overall, geriatric-focused airway management is necessary to decrease complications in this patient population. PMID:26673904

Fully optimized shaped pupils: preparation for a test at the Subaru Telescope

NASA Astrophysics Data System (ADS)

Carlotti, Alexis; Kasdin, N. Jeremy; Martinache, Frantz; Vanderbei, Robert J.; Young, Elizabeth J.; Che, George; Groff, Tyler D.; Guyon, Olivier

2012-09-01

The SCExAO instrument at the Subaru telescope, mainly based on a PIAA coronagraph can benefit from the addition of a robust and simple shaped pupil coronagraph. New shaped pupils, fully optimized in 2 dimensions, make it possible to design optimal apodizers for arbitrarily complex apertures, for instance on-axis telescopes such as the Subaru telescope. We have designed several masks with inner working angles as small as 2.5 λ / D, and for high-contrast regions with different shapes. Using Princeton University nanofabrication facilities, we have manufactured two masks by photolithography. These masks have been tested in the laboratory, both in Princeton and in the facilities of the National Astronomical Observatory of Japan (NAOJ) in Hilo. The goal of this work is to prepare tests on the sky of a shaped pupil coronagraph in 2012.

Speed isn’t everything: Complex processing speed measures mask individual differences and developmental changes in executive control

PubMed Central

Cepeda, Nicholas J.; Blackwell, Katharine A.; Munakata, Yuko

2012-01-01

The rate at which people process information appears to influence many aspects of cognition across the lifespan. However, many commonly accepted measures of “processing speed” may require goal maintenance, manipulation of information in working memory, and decision-making, blurring the distinction between processing speed and executive control and resulting in overestimation of processing-speed contributions to cognition. This concern may apply particularly to studies of developmental change, as even seemingly simple processing speed measures may require executive processes to keep children and older adults on task. We report two new studies and a re-analysis of a published study, testing predictions about how different processing speed measures influence conclusions about executive control across the life span. We find that the choice of processing speed measure affects the relationship observed between processing speed and executive control, in a manner that changes with age, and that choice of processing speed measure affects conclusions about development and the relationship among executive control measures. Implications for understanding processing speed, executive control, and their development are discussed. PMID:23432836

In vitro and in vivo investigation of taste-masking effectiveness of Eudragit E PO as drug particle coating agent in orally disintegrating tablets.

PubMed

Drašković, Milica; Medarević, Djordje; Aleksić, Ivana; Parojčić, Jelena

2017-05-01

Considering that bitter taste of drugs incorporated in orally disintegrating tablets (ODTs) can be the main reason for avoiding drug therapy, it is of the utmost importance to achieve successful taste-masking. The evaluation of taste-masking effectiveness is still a major challenge. The objective of this study was to mask bitter taste of the selected model drugs by drug particle coating with Eudragit ® E PO, as well as to evaluate taste-masking effectiveness of prepared ODTs using compendial dissolution testing, dissolution in the small-volume shake-flask assembly and trained human taste panel. Model drugs were coated in fluidized bed. Disintequik™ ODT was used as a novel co-processed excipient for ODT preparation. Selected formulations were investigated in vitro and in vivo using techniques for taste-masking assessment. Significantly slower drug dissolution was observed from tablets with coated drug particles during the first 3 min of investigation. Results of in vivo taste-masking assessment demonstrated significant improvement in drug bitterness suppression in formulations with coated drug. Strong correlation between the results of drug dissolution in the small-volume shake-flask assembly and in vivo evaluation data was established (R ≥ 0.970). Drug particle coating with Eudragit ® E PO can be a suitable approach for bitter taste-masking. Strong correlation between in vivo and in vitro results implicate that small-volume dissolution method may be used as surrogate for human panel taste-masking assessment, in the case of physical taste-masking approach application.