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Sample records for actinic mask inspection

  1. Computational defect review for actinic mask inspections

    NASA Astrophysics Data System (ADS)

    Morgan, Paul; Rost, Daniel; Price, Daniel; Corcoran, Noel; Satake, Masaki; Hu, Peter; Peng, Danping; Yonenaga, Dean; Tolani, Vikram

    2013-04-01

    As optical lithography continues to extend into low-k1 regime, resolution of mask patterns continues to diminish. The limitation of 1.35 NA posed by water-based lithography has led to the application of various resolution enhancement techniques (RET), for example, use of strong phase-shifting masks, aggressive OPC and sub-resolution assist features, customized illuminators, etc. The adoption of these RET techniques combined with the requirements to detect even smaller defects on masks due to increasing MEEF, poses considerable challenges for a mask inspection engineer. Inspecting masks under their actinic-aerial image conditions would detect defects that are more likely to print under those exposure conditions. However, this also makes reviewing such defects in their low-contrast aerial images very challenging. On the other hand, inspecting masks under higher resolution inspection optics would allow for better viewing of defects post-inspection. However, such inspections generally would also detect many more defects, including printable and nuisance, thereby making it difficult to judge which are of real concern for printability on wafer. Often, an inspection engineer may choose to use Aerial and/or high resolution inspection modes depending on where in the process flow the mask is and the specific device-layer characteristics of the mask. Hence, a comprehensive approach is needed in handling defects both post-aerial and post-high resolution inspections. This analysis system is designed for the Applied Materials Aera™ mask inspection platform, all data reported was collected using the Aera.

  2. Actinic inspection of multilayer defects on EUV masks

    SciTech Connect

    Barty, A; Liu, Y; Gullikson, E; Taylor, J S; Wood, O

    2005-03-24

    The production of defect-free mask blanks, and the development of techniques for inspecting and qualifying EUV mask blanks, remains a key challenge for EUV lithography. In order to ensure a reliable supply of defect-free mask blanks, it is necessary to develop techniques to reliably and accurately detect defects on un-patterned mask blanks. These inspection tools must be able to accurately detect all critical defects whilst simultaneously having the minimum possible false-positive detection rate. There continues to be improvement in high-speed non-actinic mask blank inspection tools, and it is anticipated that these tools can and will be used by industry to qualify EUV mask blanks. However, the outstanding question remains one of validating that non-actinic inspection techniques are capable of detecting all printable EUV defects. To qualify the performance of non-actinic inspection tools, a unique dual-mode EUV mask inspection system has been installed at the Advanced Light Source (ALS) synchrotron at Lawrence Berkeley National Laboratory. In high-speed inspection mode, whole mask blanks are scanned for defects using 13.5-nm wavelength light to identify and map all locations on the mask that scatter a significant amount of EUV light. In imaging, or defect review mode, a zone plate is placed in the reflected beam path to image a region of interest onto a CCD detector with an effective resolution on the mask of 100-nm or better. Combining the capabilities of the two inspection tools into one system provides the unique capability to determine the coordinates of native defects that can be used to compare actinic defect inspection with visible light defect inspection tools under commercial development, and to provide data for comparing scattering models for EUV mask defects.

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

    SciTech Connect

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

    2009-04-14

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

  4. A Dual-Mode Actinic EUV Mask Inspection Tool

    SciTech Connect

    Liu, Y; Barty, A; Gullikson, E; S.Taylor, J; Liddle, J A; Wood, O

    2005-03-21

    To qualify the performance of non-actinic inspection tools, a novel EUV mask inspection system has been installed at the Advanced Light Source (ALS) synchrotron facility at Lawrence Berkeley National Laboratory. Similar to the older generation actinic mask inspection tool, the new system can operate in scanning mode, when mask blanks are scanned for defects using 13.5-nm in-band radiation to identify and map all locations on the mask that scatter a significant amount of EUV light. By modifying and optimizing beamline optics (11.3.2 at ALS) and replacing K-B focusing mirrors with a high quality Schwarzschild illuminator, the new system achieves an order of magnitude improvement on in-band EUV flux density at the mask, enabling faster scanning speed and higher sensitivity to smaller defects. Moreover, the system can also operate in imaging mode, when it becomes a zone-plate-based full-field EUV microscope with spatial resolution better than 100 nm. The microscope utilizes an off-axis setup, making it possible to obtain bright field images over a field-of-view of 5 x 5 {micro}m.

  5. Mask blank defect printability comparison using optical and SEM mask and wafer inspection and bright field actinic mask imaging

    NASA Astrophysics Data System (ADS)

    Mangat, Pawitter; Verduijn, Erik; Wood, Obert R.; Benk, Markus P.; Wojdyla, Antoine; Goldberg, Kenneth A.

    2015-07-01

    Despite significant enhancements in defect detection using optical and e-beam methodology, the smaller length scales and increasing challenges of future technology nodes motivate ongoing research into the need and associated cost of actinic inspection for EUV masks. This paper reports an extensive study of two EUV patterned masks, wherein the mask blank defectivity was characterized using optical (mask and wafer) methods and bright-field mask imaging (using the SHARP actinic microscope) of previously identified blank defects. We find that the bright field actinic imaging tool microscope captures and images many defects that are not seen by the automated optical inspection of patterned masks and printed wafers. In addition, actinic review reveals the impact of multilayer damage and depicts the printability profile which can be used as an added metric to define the patterned mask repair and defect compensation strategies.

  6. Actinic Mask Inspection at the ALS Initial Design Review

    SciTech Connect

    Barty, A; Chapman, H; Sweeney, D; Levesque, R; Bokor, J; Gullikson, E; Jong, S; Liu, Y; Yi, M; Denbeaux, G; Goldberg, K; Naulleau, P; Denham, P; Rekawa, S; Baston, P; Tackaberry, R; Barale, P

    2003-03-05

    This report is the first milestone report for the actinic mask blank inspection project conducted at the VNL, which forms sub-section 3 of the Q1 2003 mask blank technology transfer program at the VNL. Specifically this report addresses deliverable 3.1.1--design review and preliminary tool design. The goal of this project is to design an actinic mask inspection tool capable of operating in two modes: high-speed scanning for the detection of multilayer defects (inspection mode), and a high-resolution aerial image mode in which the image emulates the imaging illumination conditions of a stepper system (aerial image or AIM mode). The purpose and objective of these two modes is as follows: (1) Defect inspection mode--This imaging mode is designed to scan large areas of the mask for defects EUV multilayer coatings. The goal is to detect the presence of multilayer defects on a mask blank and to store the co-ordinates for subsequent review in AIM mode, thus it is not essential that the illumination and imaging conditions match that of a production stepper. Potential uses for this imaging mode include: (a) Correlating the results obtained using actinic inspection with results obtained using other non-EUV defect inspection systems to verify that the non-EUV scanning systems are detecting all critical defects; (b) Gaining sufficient information to associate defects with particular processes, such as various stages of the multilayer deposition or different modes of operation of the deposition tool; and (c) Assessing the density and EUV impact of surface and multilayer anomalies. Because of the low defect density achieved using current multilayer coating technology it is necessary to be able to efficiently scan large areas of the mask in order to obtain sufficient statistics for use in cross-correlation experiments. Speed of operation as well as sensitivity is therefore key to operation in defect inspection mode. (2) Aerial Image Microscope (AIM) mode--In AIM mode the tool is

  7. Actinic EUV mask inspection beyond 0.25 NA

    SciTech Connect

    Goldberg, Kenneth A.; Mochi, Iacopo; Anderson, Erik H.; Rekawa, Seno B.; Kemp, Charles D.; Huh, S.; Han, H.-S.

    2008-08-06

    Operating at EUV wavelengths, the SEMATECH Berkeley Actinic Inspection Tool (AIT) is a zoneplate microscope that provides high quality aerial image measurements in routine operations for SEMATECH member companies. We have upgraded the optical performance of the AIT to provide multiple image magnifications, and several inspection NA values up to 0.35 NA equivalent (0.0875 mask-side). We report on the improved imaging capabilities including resolution below 100-nm on the mask side (25 nm, 4x wafer equivalent). EUV reticles are intricate optical systems made from of several materials with wavelength-specific optical properties. The combined interactions of the substrate, multilayer-stack, buffer layer and absorber layer produce a reflected EUV optical field that is challenging to model accurately, and difficult to fully assess without actinic at-wavelength inspection. Understanding the aerial image from lithographic printing alone is complicated by photoresist properties. The AIT is now used to investigate mask issues such as amplitude and phase defect printability, pattern repair techniques, contamination, inspection damage, and mask architecture. The AIT has a 6{sup o} illumination angle, and high-resolution exposure times are typically 20 seconds per image. The AIT operates semi-automatically capturing through-focus imaging series with step sizes as small as 0.1 {micro}m (0.5-0.8 {micro}m are typical), and a step resolution of 0.05 {micro}m. We believe it is the most advanced EUV mask inspection tool in operation today. In the AIT, an EUV image of the mask is projected by a zoneplate lens with high magnification (680-910x) onto a CCD camera. The CCD over-samples the image, providing equivalent pixel sizes down to 15 nm in mask coordinates-several image pixels per resolution element. The original AIT zoneplate specifications were designed to emulate the resolution of a 0.25-NA 4x stepper, and thorough benchmarking analysis of the aberrations, flare, contrast

  8. Actinic EUV mask inspection beyond 0.25 NA

    SciTech Connect

    Goldberg, Kenneth A.; Mochi, Iacopo; Anderson, Erik H.; Rekawa, Seno. B.; Kemp, Charles D.; Huh, S.; Han, H.-S.; Naulleau, P.; Huh, S.

    2008-03-24

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is an EUV-wavelength mask inspection microscope designed for direct aerial image measurements, and pre-commercial EUV mask research. Operating on a synchrotron bending magnet beamline, the AIT uses an off-axis Fresnel zoneplate lens to project a high-magnification EUV image directly onto a CCD camera. We present the results of recent system upgrades that have improved the imaging resolution, illumination uniformity, and partial coherence. Benchmarking tests show image contrast above 75% for 100-nm mask features, and significant improvements and across the full range of measured sizes. The zoneplate lens has been replaced by an array of user-selectable zoneplates with higher magnification and NA values up to 0.0875, emulating the spatial resolution of a 0.35-NA 4x EUV stepper. Illumination uniformity is above 90% for mask areas 2-{micro}m-wide and smaller. An angle-scanning mirror reduces the high coherence of the synchrotron beamline light source giving measured {sigma} values of approximately 0.125 at 0.0875 NA.

  9. Impact of EUVL mask surface roughness on an actinic blank inspection image and a wafer image

    NASA Astrophysics Data System (ADS)

    Yamane, Takeshi; Terasawa, Tsuneo

    2012-11-01

    An impact of EUVL mask surface roughness on actinic inspection was studied. The background level (BGL) of an actinic inspection image is caused by the light scattered from the mask blank surface roughness. The BGL is found to be proportional to the square of the mask surface roughness measured by AFM. By using this proportionality coefficient, a global distribution of the surface roughness can be obtained at the same time while inspection a mask. On the other hand, any local variation of BGL indicates variation of the mask surface roughness at each pixel. Assuming that the roughness at a center pixel is 0.15 nm rms (SEMI standard specification) and those at the surrounding pixels are 0.1 nm rms, the signal intensity at the center pixel is found to be approximately the same as that of a 1.2 nm-high and 40 nm-wide programmed defect. In that case, CD error on a wafer image due to the reflectivity loss by the roughness is found to be not critical. This means that the local roughness should be less than 0.15 nm rms, and that the inspection system can detect such a local variation of the roughness with 100 % probability.

  10. ACTINIC MASK INSPECTION AT THE ALS: RISK REDUCTION ACTIVITIES FOR 2003

    SciTech Connect

    Barty, A; Levesque, R; Ayers, J; Liu, Y; Gullikson, E; Barale, P

    2004-01-05

    This document reports on risk reduction activities performed at the VNL during CY2003 as a part of the Lith-343 actinic inspection project funded by International SEMATECH. The risk reduction activities described in this document comprise deliverable items 3.1.3, 3.1.4, 3.1.5 and 3.1.6 of Amendment 6 to the VNL EUV mask blank technology transfer contract.

  11. Phase defect analysis with actinic full-field EUVL mask blank inspection

    NASA Astrophysics Data System (ADS)

    Yamane, Takeshi; Tanaka, Toshihiko; Terasawa, Tsuneo; Suga, Osamu

    2011-11-01

    We had developed an actinic full-field inspection system to detect multilayer phase-defects with dark field imaging. Regarding the actinic inspection of native defects, the influence of the defect's surface dimension and multilayer structure, on the intensity-signal obtained from the inspection was analyzed. Three mask blanks were inspected from which 55 defects, observed with AFM and SEM, were classified as amplitude-defects or phase-defects. The surface dimensions and SEVDs (sphere equivalent volume diameters) of the defects were measured with the AFM. In the case where their SEVDs were same as of the programmed phase-defects, they were found to produce stronger intensitysignals in comparison to the ones from the programmed phase-defects. Cross-sectional multilayer structures of two native phase-defects were observed with TEM, and those defects formed non-conformal structures in the multilayer. This result means that most of the native phase-defects tend to form a non-conformal structure, and can make large impact on the wafer image in comparison to the ones from a conformal structure. Besides phase-defects, the actinic inspection also detected amplitude-defects. Although the sensitivities of the amplitude-defects were found to be lower than those of the phase-defects, an amplitude-defect higher than 30 nm could be detected with high probability.

  12. Investigation of buried EUV mask defect printability using actinic inspection and fast simulation

    SciTech Connect

    Clifford, C. H.; Chan, T. T.; Neureuther, A. R.; Goldberg, K. A.; Mochi, I.; Liang, T.

    2009-06-16

    The fast simulator RADICAL and the Actinic Inspection Tool (AIT) are used in advance of availability of high volume manufacturing quality exposure tools, resists, and masks to assess the expected defect printability levels in production conditions. AIT images are analyzed to qualitatively demonstrate general trends in defect printability: defects smaller than 0.5nm tall on the multilayer surface can cause an unacceptable critical dimension (CD) change, CD change increases for taller defects, and defect printability varies asymmetrically through focus. RADICAL is used to derive quantitative limits for defect size and demonstrate the effects of focus and illumination for 22nm and 16nm dense lines. For 22nm dense lines at best focus a 0.8nm tall defect causes a 10% CD change. For 16nm lines a 0.4nm tall defect causes a 10% CD change. The CD is shown to be more sensitive to buried defects out of focus, but less sensitive to defects in focus if annular or dipole illumination is used.

  13. Wavelength-specific reflections: A decade of EUV actinic mask inspection research

    SciTech Connect

    Goldberg, Kenneth; Mochi, Iacopo

    2010-12-31

    Mask inspection is essential for the success of any pattern-transfer lithography technology, and EUV Lithography in particular faces unique challenges. EUV masks resonant-reflective multilayer coatings have a narrow, wavelength-specific response that dramatically affects the way that defects appear, or disappear, at various illuminating wavelengths. Furthermore, the ever-shrinking size of 'critical' defects limits the potential effectiveness of DUV inspection techniques over time. Researchers pursuing numerous ways of finding and characterizing defects on EUV masks and have met with varying degrees of success. Their lessons inform the current, urgent exploration to select the most effective techniques for high-volume manufacturing. Ranging from basic research and demonstration experiments to commercial inspection tool prototypes, we survey the recent history of work in this area, including sixteen projects in Europe, Asia, and America. Solutions range from scanning beams to microscopy, dark field imaging to pattern transfer.

  14. Comparison of fast 3D simulation and actinic inspection for EUV masks with buries defects

    SciTech Connect

    Clifford, C. H.; Wiraatmadja, S.; Chan, T. T.; Neureuther, A. R.; Goldberg, K. A.; Mochi, I.; Liang, T.

    2009-02-23

    Aerial images for isolated defects and the interactions of defects with features are compared between the Actinic Inspection Tool (AIT) at Lawrence Berkeley National Laboratory (LBNL) and the fast EUV simulation program RADICAL. Comparisons between AIT images from August 2007 and RADICAL simulations are used to extract aberrations. At this time astigmatism was the dominant aberration with a value of 0.55 waves RMS. Significant improvements in the imaging performance of the AIT were made between August 2007 and December 2008. A good match will be shown between the most recent AIT images and RADICAL simulations without aberrations. These comparisons will demonstrate that a large defect, in this case 7nm tall on the surface, is still printable even if it is centered under the absorber line. These comparisons also suggest that the minimum defect size is between 1.5nm and 0.8nm surface height because a 1.5nm defect was printable but a 0.8nm was not. Finally, the image of a buried defect near an absorber line through focus will demonstrate an inversion in the effect of the defect from a protrusion of the dark line into the space to a protrusion of the space into the line.

  15. Actinic review of EUV masks

    NASA Astrophysics Data System (ADS)

    Feldmann, Heiko; Ruoff, Johannes; Harnisch, Wolfgang; Kaiser, Winfried

    2010-04-01

    Management of mask defects is a major challenge for the introduction of EUV for HVM production. Once a defect has been detected, its printing impact needs to be predicted. Potentially the defect requires some repair, the success of which needs to be proven. This defect review has to be done with an actinic inspection system that matches the imaging conditions of an EUV scanner. During recent years, several concepts for such an aerial image metrology system (AIMS™) have been proposed. However, until now no commercial solution exists for EUV. Today, advances in EUV optics technology allow envisioning a solution that has been discarded before as unrealistic. We present this concept and its technical cornerstones.While the power requirement for the EUV source is less demanding than for HVM lithography tools, radiance, floor space, and stability are the main criteria for source selection. The requirement to emulate several generations of EUV scanners demands a large flexibility for the ilumination and imaging systems. New critical specifications to the EUV mirrors in the projection microscope can be satisfied using our expertise from lithographic mirrors. In summary, an EUV AIMS™ meeting production requirements seems to be feasible.

  16. EUV actinic brightfield mask microscopy for predicting printed defect images

    NASA Astrophysics Data System (ADS)

    Goldberg, Kenneth; Benk, Markus P.; Wojdyla, Antoine; Verduijn, Erik; Wood, Obert R.; Mangat, Pawitter

    2015-10-01

    Improving our collective understanding of extreme ultraviolet (EUV) photomask defects and the imaging properties of available defect imaging tools is essential for improving EUV mask defectivity, defect repair and mitigation, and for high-level strategic decision-making. In this work, we perform a qualitative comparison of twenty-five defects imaged with mask scanning electron microscopy (SEM), EUV actinic mask imaging, and wafer SEM imaging. All but two of the defect locations were first identified by non-actinic mask blank inspection, prior to patterning. The others were identified as repeating defects on the wafer. We find that actinic defect imaging is predictive of the wafer prints, with small-scale features clearly replicated. While some mask defect SEM images match the wafer prints, others print with a larger outline indicating the presence of sub-surface disruptions hidden from the SEM's view. Fourteen other defects were subjected to an aerial image phase measurement method called Fourier Ptychography (FP). Although phase shifts were observed in the larger defects, the smaller defects in the dataset showed no significant phase shifting. We attribute this discrepancy to non-actinic mask blank inspection's limited ability to detect small phase defects under normal operating conditions.

  17. Multilayer defects nucleated by substrate pits: a comparison of actinic inspection and non-actinic inspection techniques

    SciTech Connect

    Barty, A; Goldberg, K; Kearney, P; Rekawa, S; LaFontaine, B; Wood, O; Taylor, J S; Han, H

    2006-10-02

    The production of defect-free mask blanks remains a key challenge for EUV lithography. Mask-blank inspection tools must be able to accurately detect all critical defects while simultaneously having the minimum possible false-positive detection rate. We have recently observed and here report the identification of bump-type buried substrate defects, that were below the detection limit of a non-actinic (i.e. non-EUV) in inspection tool. Presently, the occurrence inspection of pit-type defects, their printability, and their detectability with actinic techniques and non-actinic commercial tools, has become a significant concern. We believe that the most successful strategy for the development of effective non-actinic mask inspection tools will involve the careful cross-correlation with actinic inspection and lithographic printing. In this way, the true efficacy of prototype inspection tools now under development can be studied quantitatively against relevant benchmarks. To this end we have developed a dual-mode actinic mask inspection system capable of scanning mask blanks for defects (with simultaneous EUV bright-field and dark-field detection) and imaging those same defects with a zoneplate microscope that matches or exceeds the resolution of EUV steppers.

  18. Advances in the detection capability on actinic blank inspection

    NASA Astrophysics Data System (ADS)

    Yamane, Takeshi; Amano, Tsuyoshi; Takagi, Noriaki; Watanabe, Hidehiro; Mori, Ichro; Ino, Tomohisa; Suzuki, Tomohiro; Takehisa, Kiwamu; Miyai, Hiroki; Kusunose, Haruhiko

    2016-03-01

    Improvements in the detection capability of a high-volume-manufacturing (HVM) actinic blank inspection (ABI) prototype for native defects caused by illumination numerical aperture (NA) enlargement were evaluated. A mask blank was inspected by varying the illumination NA. The defect signal intensity increased with illumination NA enlargement as predicted from simulation. The mask blank was also inspected with optical tools, and no additional phase defect was detected. All of the printable phase defects were verified to have been detected by the HVM ABI prototype.

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

    SciTech Connect

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

    2010-03-12

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

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

    SciTech Connect

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

    2007-09-25

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

  1. Performance of actinic EUVL mask imaging using a zoneplatemicroscope

    SciTech Connect

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

    2007-08-20

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

  2. Inspection of lithographic mask blanks for defects

    DOEpatents

    Sommargren, Gary E.

    2001-01-01

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

  3. Computational mask defect review for contamination and haze inspections

    NASA Astrophysics Data System (ADS)

    Morgan, Paul; Rost, Daniel; Price, Daniel; Corcoran, Noel; Satake, Masaki; Hu, Peter; Peng, Danping; Yonenaga, Dean; Tolani, Vikram; Wolf, Yulian; Shah, Pinkesh

    2013-09-01

    As optical lithography continues to extend into sub-0.35 k1 regime, mask defect inspection and subsequent review has become tremendously challenging, and indeed the largest component to mask manufacturing cost. The routine use of various resolution enhancement techniques (RET) have resulted in complex mask patterns, which together with the need to detect even smaller defects due to higher MEEFs, now requires an inspection engineer to use combination of inspection modes. This is achieved in 193nm AeraTM mask inspection systems wherein masks are not only inspected at their scanner equivalent aerial exposure conditions, but also at higher Numerical Aperture resolution, and special reflected-light, and single-die contamination modes, providing better coverage over all available patterns, and defect types. Once the required defects are detected by the inspection system, comprehensively reviewing and dispositioning each defect then becomes the Achilles heel of the overall mask inspection process. Traditionally, defects have been reviewed manually by an operator, which makes the process error-prone especially given the low-contrast in the convoluted aerial images. Such manual review also limits the quality and quantity of classifications in terms of the different types of characterization and number of defects that can practically be reviewed by a person. In some ways, such manual classification limits the capability of the inspection tool itself from being setup to detect smaller defects since it often results in many more defects that need to be then manually reviewed. Paper 8681-109 at SPIE Advanced Lithography 2013 discussed an innovative approach to actinic mask defect review using computational technology, and focused on Die-to-Die transmitted aerial and high-resolution inspections. In this approach, every defect is characterized in two different ways, viz., quantitatively in terms of its print impact on wafer, and qualitatively in terms of its nature and origin in

  4. Actinic imaging of native and programmed defects on a full-field mask

    SciTech Connect

    Mochi, I.; Goldberg, K. A.; Fontaine, B. La; Tchikoulaeva, A.; Holfeld, C.

    2010-03-12

    We describe the imaging and characterization of native defects on a full field extreme ultraviolet (EUV) mask, using several reticle and wafer inspection modes. Mask defect images recorded with the SEMA TECH Berkeley Actinic Inspection Tool (AIT), an EUV-wavelength (13.4 nm) actinic microscope, are compared with mask and printed-wafer images collected with scanning electron microscopy (SEM) and deep ultraviolet (DUV) inspection tools. We observed that defects that appear to be opaque in the SEM can be highly transparent to EUV light, and inversely, defects that are mostly transparent to the SEM can be highly opaque to EUV. The nature and composition of these defects, whether they appear on the top surface, within the multilayer coating, or on the substrate as buried bumps or pits, influences both their significance when printed, and their detectability with the available techniques. Actinic inspection quantitatively predicts the characteristics of printed defect images in ways that may not be possible with non-EUV techniques. As a quantitative example, we investigate the main structural characteristics of a buried pit defect based on EUV through-focus imaging.

  5. Benchmarking EUV mask inspection beyond 0.25 NA

    SciTech Connect

    Goldberg, Kenneth A.; Mochi, Iacopo; Anderson, Erik H.; Rekawa, Seno B.; Kemp, Charles D.; Huh, S.; Han, H.-S.; Naulleau, P.; Gunion, R.F.

    2008-09-18

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is an EUV-wavelength mask inspection microscope designed for direct aerial image measurements, and pre-commercial EUV mask research. Operating on a synchrotron bending magnet beamline, the AIT uses an off-axis Fresnel zoneplate lens to project a high-magnification EUV image directly onto a CCD camera. We present the results of recent system upgrades that have improved the imaging resolution, illumination uniformity, and partial coherence. Benchmarking tests show image contrast above 75% for 100-nm mask features, and significant improvements and across the full range of measured sizes. The zoneplate lens has been replaced by an array of user-selectable zoneplates with higher magnification and NA values up to 0.0875, emulating the spatial resolution of a 0.35-NA 4 x EUV stepper. Illumination uniformity is above 90% for mask areas 2-{micro}m-wide and smaller. An angle-scanning mirror reduces the high coherence of the synchrotron beamline light source giving measured {sigma} values of approximately 0.125 at 0.0875 NA.

  6. EUV actinic defect inspection and defect printability at the sub-32 nm half pitch

    SciTech Connect

    Huh, Sungmin; Kearney, Patrick; Wurm, Stefan; Goodwin, Frank; Han, Hakseung; Goldberg, Kenneth; Mochi, Iacopp; Gullikson, Eric M.

    2009-08-01

    Extreme ultraviolet (EUV) mask blanks with embedded phase defects were inspected with a reticle actinic inspection tool (AIT) and the Lasertec M7360. The Lasertec M7360, operated at SEMA TECH's Mask Blank Development Center (MBDC) in Albany, NY, has a sensitivity to multilayer defects down to 40-45 nm, which is not likely sufficient for mask blank development below the 32 nm half-pitch node. Phase defect printability was simulated to calculate the required defect sensitivity for a next generation blank inspection tool to support reticle development for the sub-32 nm half-pitch technology node. Defect mitigation technology is proposed to take advantage of mask blanks with some defects. This technology will reduce the cost of ownership of EUV mask blanks. This paper will also discuss the kind of infrastructure that will be required for the development and mass production stages.

  7. Pattern inspection of etched multilayer EUV mask

    NASA Astrophysics Data System (ADS)

    Iida, Susumu; Hirano, Ryoichi; Amano, Tsuyoshi; Watanabe, Hidehiro

    2015-07-01

    Patterned mask inspection for an etched multilayer (ML) EUV mask was investigated. In order to optimize the mask structure from the standpoint of not only a pattern inspection by using a projection electron microscope (PEM), but also by considering the other fabrication processes using electron beam (EB) techniques such as CD metrology and mask repair, we employed a conductive layer between the ML and substrate. By measuring the secondary electron emission coefficients (SEECs) of the candidate materials for conductive layer, we evaluated the image contrast and the influence of charging effect. In the cases of 40-pair-ML, 16 nm sized extrusion and intrusion defects were found to be detectable more than 10 sigma in hp 44 nm, 40 nm, and 32 nm line and space (L/S) patterns. Reducing 40-pair-ML to 20-pair-ML degraded the image contrast and the defect detectability. However, by selecting B4C as a conductive layer, 16 nm sized defects remained detectable. A double layer structure with 2.5-nm-thik B4C on metal film used as a conductive layer was found to have sufficient conductivity and also was found to be free from the surface charging effect and influence of native oxide.

  8. Pattern inspection of etched multilayer EUV mask

    NASA Astrophysics Data System (ADS)

    Iida, Susumu; Hirano, Ryoichi; Amano, Tsuyoshi; Watanabe, Hidehiro

    2015-10-01

    Patterned mask inspection for an etched multilayer (ML) EUV mask was investigated. In order to optimize the mask structure from the standpoint of not only a pattern inspection by using a projection electron microscope (PEM), but also by considering the other fabrication processes using electron beam (EB) techniques such as CD metrology and mask repair, we employed a conductive layer between the ML and substrate. By measuring the secondary electron emission coefficients (SEECs) of the candidate materials for conductive layer, we evaluated the image contrast and the influence of charging effect. In the cases of 40-pair-ML, 16 nm sized extrusion and intrusion defects were found to be detectable more than 10 sigma in hp 44 nm, 40 nm, and 32 nm line and space (L/S) patterns. Reducing 40-pair-ML to 20-pair-ML degraded the image contrast and the defect detectability. However, by selecting B4C as a conductive layer, 16 nm sized defects remained detectable. These defects were also detected after the etched part was refilled with Si. Moreover, the simulation shows a high sensitivity for detecting the residual-type defects (etching residues). A double layer structure with 2.5-nm-thik B4C on metal film used as a conductive layer was found to have sufficient conductivity and also was found to be free from the surface charging effect and influence of native oxide.

  9. 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.

  10. Actinic imaging and evaluation of phase structures on EUV lithography masks

    SciTech Connect

    Mochi, Iacopo; Goldberg, Kenneth; Huh, Sungmin

    2010-09-28

    The authors describe the implementation of a phase-retrieval algorithm to reconstruct phase and complex amplitude of structures on EUV lithography masks. Many native defects commonly found on EUV reticles are difficult to detect and review accurately because they have a strong phase component. Understanding the complex amplitude of mask features is essential for predictive modeling of defect printability and defect repair. Besides printing in a stepper, the most accurate way to characterize such defects is with actinic inspection, performed at the design, EUV wavelength. Phase defect and phase structures show a distinct through-focus behavior that enables qualitative evaluation of the object phase from two or more high-resolution intensity measurements. For the first time, phase of structures and defects on EUV masks were quantitatively reconstructed based on aerial image measurements, using a modified version of a phase-retrieval algorithm developed to test optical phase shifting reticles.

  11. A new approach for defect inspection on large area masks

    NASA Astrophysics Data System (ADS)

    Scheuring, Gerd; Döbereiner, Stefan; Hillmann, Frank; Falk, Günther; Brück, Hans-Jürgen

    2007-02-01

    Besides the mask market for IC manufacturing, which mainly uses 6 inch sized masks, the market for the so called large area masks is growing very rapidly. Typical applications of these masks are mainly wafer bumping for current packaging processes, color filters on TFTs, and Flip Chip manufacturing. To expose e.g. bumps and similar features on 200 mm wafers under proximity exposure conditions 9 inch masks are used, while in 300 mm wafer bumping processes (Fig. 1) 14 inch masks are handled. Flip Chip manufacturing needs masks up to 28 by 32 inch. This current maximum mask dimension is expected to hold for the next 5 years in industrial production. On the other hand shrinking feature sizes, just as in case of the IC masks, demand enhanced sensitivity of the inspection tools. A defect inspection tool for those masks is valuable for both the mask maker, who has to deliver a defect free mask to his customer, and for the mask user to supervise the mask behavior conditions during its lifetime. This is necessary because large area masks are mainly used for proximity exposures. During this process itself the mask is vulnerable by contacting the resist on top of the wafers. Therefore a regular inspection of the mask after 25, 50, or 100 exposures has to be done during its whole lifetime. Thus critical resist contamination and other defects, which lead to yield losses, can be recognized early. In the future shrinking feature dimensions will require even more sensitive and reliable defect inspection methods than they do presently. Besides the sole inspection capability the tools should also provide highly precise measurement capabilities and extended review options.

  12. Coherent scattering microscopy as an effective inspection tool for analyzing performance of phase shift mask.

    PubMed

    Woo, Dong Gon; Lee, Jae Uk; Hong, Seong Chul; Kim, Jung Sik; Ahn, Jinho

    2016-05-30

    The imaging performance of a half-tone phase shift mask (PSM) has been analyzed using coherent scattering microscopy (CSM), which allows analysis of the actinic characteristics of an extreme ultraviolet (EUV) mask such as its reflectivity, diffraction efficiency, and phase information. This paper presents the 1st experimental result showing the effect of 180° phase difference between the absorber and reflector in EUV mask. This reveals that a PSM offers a 46% improvement in 1st/0th diffraction efficiency and 14% improvement in image contrast when compared to a binary intensity mask (BIM). The horizontal-vertical critical dimension (H-V CD) bias is also reduced by 1.37 nm at 22 nm line and space (L/S) patterns. Since the performance of PSM can be evaluated without a wafer patterning process, CSM is expected to be a useful inspection tool for the development of novel EUV masks. PMID:27410126

  13. Practical mask inspection system with printability and pattern priority verification

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Hideo; Ozaki, Fumio; Takahara, Kenichi; Inoue, Takafumi; Kikuiri, Nobutaka

    2011-05-01

    Through the four years of study in Association of Super-Advanced Electronics Technologies (ASET) on reducing mask manufacturing Turn Around Time (TAT) and cost, we have been able to establish a technology to improve the efficiency of the review process by applying a printability verification function that utilizes computational lithography simulations to analyze defects detected by a high-resolution mask inspection system. With the advent of Source-Mask Optimization (SMO) and other technologies that extend the life of existing optical lithography, it is becoming extremely difficult to judge a defect only by the shape of a mask pattern, while avoiding pseudo-defects. Thus, printability verification is indispensable for filtering out nuisance defects from high-resolution mask inspection results. When using computational lithography simulations to verify printability with high precision, the image captured by the inspection system must be prepared with extensive care. However, for practical applications, this preparation process needs to be simplified. In addition, utilizing Mask Data Rank (MDR) to vary the defect detection sensitivity according to the patterns is also useful for simultaneously inspecting minute patterns and avoiding pseudo-defects. Combining these two technologies, we believe practical mask inspection for next generation lithography is achievable. We have been improving the estimation accuracy of the printability verification function through discussion with several customers and evaluation of their masks. In this report, we will describe the progress of these practical mask verification functions developed through customers' evaluations.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  15. Actinic Inspection of EUV Programmed Multilayer Defects and Cross-Comparison Measurements

    SciTech Connect

    Goldberg, K; Barty, A; Liu, Y; Kearney, P; Tezuka, Y; Terasawa, T; Taylor, J S; Han, H; Wood, O

    2006-06-19

    The production of defect-free mask blanks remains a key challenge for extreme ultraviolet (EUV) lithography. Integral to this effort is the development and characterization of mask inspection tools that are sensitive enough to detect critical defects with high confidence. Using a single programmed-defect mask with a range of buried bump-type defects, we report a comparison of measurements made in four different mask-inspection tools: one commercial tool using 488-nm wavelength illumination, one prototype tool that uses 266-nm illumination, and two non-commercial EUV ''actinic'' inspection tools. The EUV tools include a darkfield imaging microscope and a scanning microscope. Our measurements show improving sensitivity with the shorter wavelength non-EUV tool, down to 33-nm spherical-equivalent-volume diameter, for defects of this type. Measurements conditions were unique to each tool, with the EUV tools operating at a much slower inspection rate. Several defects observed with EUV inspection were below the detection threshold of the non-EUV tools.

  16. Method and apparatus for inspecting an EUV mask blank

    DOEpatents

    Goldberg, Kenneth A.

    2005-11-08

    An apparatus and method for at-wavelength EUV mask-blank characterization for inspection of moderate and low spatial frequency coating uniformity using a synchrotron or other source of EUV light. The apparatus provides for rapid, non-destruction, non-contact, at-wavelength qualification of large mask areas, and can be self-calibrating or be calibrated to well-characterized reference samples. It can further check for spatial variation of mask reflectivity or for global differences among masks. The apparatus and method is particularly suited for inspection of coating uniformity and quality and can detect defects in the order of 50 .mu.m and above.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it's imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMSTM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts

  18. Improve mask inspection capacity with Automatic Defect Classification (ADC)

    NASA Astrophysics Data System (ADS)

    Wang, Crystal; Ho, Steven; Guo, Eric; Wang, Kechang; Lakkapragada, Suresh; Yu, Jiao; Hu, Peter; Tolani, Vikram; Pang, Linyong

    2013-09-01

    As optical lithography continues to extend into low-k1 regime, resolution of mask patterns continues to diminish. The adoption of RET techniques like aggressive OPC, sub-resolution assist features combined with the requirements to detect even smaller defects on masks due to increasing MEEF, poses considerable challenges for mask inspection operators and engineers. Therefore a comprehensive approach is required in handling defects post-inspections by correctly identifying and classifying the real killer defects impacting the printability on wafer, and ignoring nuisance defect and false defects caused by inspection systems. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at the SMIC mask shop for the 40nm technology node. Traditionally, each defect is manually examined and classified by the inspection operator based on a set of predefined rules and human judgment. At SMIC mask shop due to the significant total number of detected defects, manual classification is not cost-effective due to increased inspection cycle time, resulting in constrained mask inspection capacity, since the review has to be performed while the mask stays on the inspection system. Luminescent Technologies Automated Defect Classification (ADC) product offers a complete and systematic approach for defect disposition and classification offline, resulting in improved utilization of the current mask inspection capability. Based on results from implementation of ADC in SMIC mask production flow, there was around 20% improvement in the inspection capacity compared to the traditional flow. This approach of computationally reviewing defects post mask-inspection ensures no yield loss by qualifying reticles without the errors associated with operator mis-classification or human error. The ADC engine retrieves the high resolution inspection images and uses a decision-tree flow to classify a given defect. Some identification mechanisms adopted by ADC to

  19. EUV scanner printability evaluation of natural blank defects detected by actinic blank inspection

    NASA Astrophysics Data System (ADS)

    Takagi, Noriaki; Watanabe, Hidehiro; Van den Heuvel, Dieter; Jonckheere, Rik; Gallagher, Emily

    2015-07-01

    In this study, on-wafer printability test results of native blank defects on an EUV reticle, previously detected on the ABI (Actinic blank inspection) tool, were interpreted with on-mask analysis. One of the main factors that affects printability is the relative defect position to the absorber pattern. The ABI tool has been used for this purpose, by means of on-mask review. Subsequently, by removing covered defects (blank defects which are covered with absorber pattern), a clear relationship between DSI (ABI defect signal intensity) and printability was confirmed. By considering a relationship between relative defect position and printability precisely, a tentative printability threshold was defined with DSI. This result suggests that DSI has valuable information to define printability threshold, and shows significance of ABI inspection.

  20. Aerial Image Microscopes for the Inspection of Defects in EUV Masks

    SciTech Connect

    Barty, A; Taylor, J S; Hudyma, R; Spiller, E; Sweeney, D W; Shelden, G; Urbach, J-P

    2002-10-22

    The high volume inspection equipment currently available to support development of EUV blanks is non-actinic. The same is anticipated for patterned EUV mask inspection. Once potential defects are identified and located by such non-actinic inspection techniques, it is essential to have instrumentation to perform detailed characterization, and if repairs are performed, re-evaluation. The ultimate metric for the acceptance or rejection of a mask due to a defect, is the wafer level impact. Thus measuring the aerial image for the site under question is required. An EUV Aerial Image Microscope (''AIM'') similar to the current AIM tools for 248nm and 193nm exposure wavelength is the natural solution for this task. Due to the complicated manufacturing process of EUV blanks, AIM measurements might also be beneficial to accurately assessing the severity of a blank defect. This is an additional application for an EUV AIM as compared to today's use In recognition of the critical role of an EUV AIM for the successful implementation of EUV blank and mask supply, International SEMATECH initiated this design study with the purpose to define the technical requirements for accurately simulating EUV scanner performance, demonstrating the feasibility to meet these requirements and to explore various technical approaches to building an EUV AIM tool.

  1. Through-pellicle defect inspection of EUV masks using an ArF-based inspection tool

    NASA Astrophysics Data System (ADS)

    Goldfarb, Dario L.; Broadbent, William; Wylie, Mark; Felix, Nelson; Corliss, Daniel

    2016-03-01

    The use of EUV photomasks in a semiconductor manufacturing environment requires their periodic inspection to ensure they are continually free of defects that could impact device yield. Defects typically occur from fall-on particles or from surface degradation such as "haze". The proposed use of a polycrystalline-based EUV pellicle to prevent fall-on particles would preclude periodic through-pellicle mask defect inspection using e-beam, as well as, DUV inspection tools (the pellicle is opaque at DUV wavelengths). Thus, to use these types of defect inspection tools would require removal of the EUV pellicle before inspection. After inspection, the pellicle would need to be re-attached and the mask re-qualified using a test wafer, thus causing expense and delays. While EUV-wavelength inspection tools could inspect through such a pellicle precluding the need to remove the pellicle, these tools are not likely to be available in the commercial marketplace for many years. An alternate EUV pellicle material has been developed that is semi-transparent to 193nm wavelengths, thus allowing through-pellicle inspection using existing ArF-based, or other 193nm wavelength mask inspection tools. This eliminates the requirement to remove the pellicle for defect inspection and the associated time and expense. In this work, we will conduct an initial evaluation of through-pellicle EUV mask defect inspection using an existing 193nm mask inspection tool. This initial evaluation will include durability of the pellicle to defect inspection, and impact of the pellicle on inspection tool performance.

  2. Top Level User Specifications for Mask Inspection Microscope

    SciTech Connect

    Barty, A; Taylor, J S

    2002-01-31

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

  3. Pattern inspection of etched multilayer extreme ultraviolet mask

    NASA Astrophysics Data System (ADS)

    Iida, Susumu; Hirano, Ryoichi; Amano, Tsuyoshi; Watanabe, Hidehiro

    2016-04-01

    Patterned mask inspection for an etched multilayer (ML) extreme ultraviolet mask was investigated. In order to optimize the mask structure from the standpoint of a pattern inspection the mask structure not only from the standpoint of a pattern inspection by using a projection electron microscope but also by using a projection electron microscope but also by considering the other fabrication processes using electron beam techniques such as critical dimension metrology and mask repair, we employed a conductive layer between the ML and substrate. By measuring the secondary electron emission coefficients of the candidate materials for the conductive layer, we evaluated the image contrast and the influence of the charging effect. In the cases of 40-pair ML, 16-nm-sized extrusion and intrusion defects were found to be detectable more than 10 sigma in half pitch 44, 40, and 32 nm line-and-space patterns. Reducing 40-pair ML to 20-pair ML degraded the image contrast and the defect detectability. However, by selecting B4C as a conductive layer, 16-nm-sized defects and etching residues remained detectable. The 16-nm-sized defects were also detected after the etched part was refilled with Si. A double-layer structure with 2.5-nm-thick B4C on metal film used as a conductive layer was found to have sufficient conductivity and also was found to be free from the surface charging effect and influence of native oxide.

  4. Method and apparatus for inspecting reflection masks for defects

    DOEpatents

    Bokor, Jeffrey; Lin, Yun

    2003-04-29

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

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

    SciTech Connect

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

    2000-02-18

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

  6. Mask rule check for inspection of leading-edge photomask

    NASA Astrophysics Data System (ADS)

    Sakata, Wakahiko; Yamasaki, Kiyoshi; Narukawa, Shogo; Hayashi, Naoya

    2005-11-01

    Leading-edge photomask, to which optical proximity correction (OPC) and dummy pattern are applied, almost always has complex patterns. Complex patterns such as "Narrow Space", "Thin Pattern", "Dummy Pattern", "Closely Face-to-Face Heads" of Posi Serifs, "Narrow Waisted Pattern" formed by a Nega Serif, "Jogs", etc. are a factor to complicate photomask manufacturing. Some the problems caused by complex patterns are increase in EB writing time, and decrease in performance of etching and cleaning process caused by Cr peeling and, above all, increase in the inspection time. Patterns whose complexity is beyond the resolution limit of inspection tool are detected as false defects. Therefore, it will greatly take time for the data investigation and re-inspection, etc. for assurance, and this causes congestion of half-finished products. To improve the process efficiency, it is necessary to locate false defects, so that the Do-Not-Inspection-Area(DNIR) or replaced with simpler patterns. In order to locate false defects, it is proposed to apply Mask Rule Check (MRC) to mask data for EB-writing.

  7. Study of EUVL mask defect inspection using 199-nm inspection tool with super-resolution method

    NASA Astrophysics Data System (ADS)

    Shigemura, Hiroyuki; Amano, Tsuyoshi; Arisawa, Yukiyasu; Suga, Osamu; Hashimoto, Hideaki; Saito, Masanori; Takeda, Masaya; Kikuiri, Nobutaka; Hirano, Ryoichi

    2009-10-01

    In this paper, we will report on our experimental results on the impact of inspection system optics on mask defect detection sensitivity. We evaluated the capability of detecting defects on the EUVL masks by using a new inspection tool (NPI6000EUVα) made by NuFlare Technology, Inc. (NFT) and Advanced Mask Inspection Technology, Inc. (AMiT). This tool is based on NPI-5000 which is the leading-edge photomask defect inspection system using 199nm wavelength inspection optics. The programmed defect mask with LR-TaBN absorber was used which had various sized opaque and clear extension defects on hp-180nm, hp-128nm, and hp-108nm line and space patterns. According to the analysis, to obtain optimum sensitivity for various types of defects, using both C- and P-polarized illumination conditions were found to be effective. At present, sufficient defect-detection sensitivity is achieved for opaque and clear extension defects in hp128nm (hp32nm at wafer). For hp108nm (hp27nm at wafer), using both C- and P- polarized illumination is effective. However, further developments in defect-detection sensitivity are necessary.

  8. Evaluation of EUVL mask pattern defect inspection using 199nm inspection tool with super-resolution method

    NASA Astrophysics Data System (ADS)

    Shigemura, Hiroyuki; Amano, Tsuyoshi; Nishiyama, Yasushi; Suga, Osamu; Arisawa, Yukiyasu; Hashimoto, Hideaki; Takahara, Kenichi; Usuda, Kinya; Kikuiri, Nobutaka; Hirano, Ryoichi

    2009-04-01

    In this paper, we will report on our experimental and simulation results on the impact of EUVL mask absorber structure and of inspection system optics on mask defect detection sensitivity. We employed a commercial simulator EM-Suite (Panoramic Technology, Inc.) which calculated rigorously using FDTD (Finite-difference time-domain) method. By using various optical constants of absorber stacks, we calculated image contrasts and defect image signals as obtained from the mask defect inspection system. We evaluated the image contrast and the capability of detecting defects on the EUVL masks by using a new inspection tool made by NuFlare Technology, Inc. (NFT) and Advanced Mask Inspection Technology, Inc. (AMiT). This tool is based on NPI-5000 which is the leading-edge photomask defect inspection system using 199nm wavelength inspection optics. The programmed defect masks with LR-TaBN and LRTaSi absorbers were used which had various sized opaque and clear extension defects on hp-160nm, hp-225nm, and hp- 325nm line and space patterns. According to the analysis, reflectivity of EUVL mask absorber structures and the inspection optics have large influence on image contrast and defect sensitivity. It is very important to optimize absorber structure and inspection optics for the development of EUVL mask inspection technology, and for the improvement of performance of EUV lithographic systems.

  9. EUV actinic blank inspection tool with a high magnification review mode

    NASA Astrophysics Data System (ADS)

    Suzuki, Tomohiro; Miyai, Hiroki; Takehisa, Kiwamu; Kusunose, Haruhiko; Yamane, Takeshi; Terasawa, Tsuneo; Watanabe, Hidehiro; Inoue, Soichi; Mori, Ichiro

    2012-06-01

    Because the realization of defect-free Extreme Ultra-violet Lithography (EUVL) mask blanks is uncertain, the defect mitigation techniques are becoming quite important. One mitigation technique, "Pattern shift", is a technique that places a device pattern to cover multilayer (ML) defects underneath the absorber pattern in such a way that the ML defects are not printed onto wafers. This mitigation method requires the defect coordinate accuracy of down to tens of nanometers. Consequently, there is a strong demand for a Blank Inspection tool that is capable of providing such defect coordinate accuracy. To meet such requirement, we have started to develop a high accuracy defect locating function as an optional feature to our EUV Actinic Blank Inspection (ABI) system which is currently being developed aiming at HVM hp16 nm-11 nm node. Since a 26x Schwarzschild optics is used in this inspection tool, it is quite difficult to pinpoint defect location with high accuracy. Therefore we have decided to realize a high magnification review optics of 600x or higher by adding two mirrors to the Schwarzschild optics. One of the additional two mirrors is retractable so that the magnification can be switched according to the purpose of inspections. The high magnification review mode locates defect coordinates accurately with respect to the fiducial position. We set the accuracy target at 20 nm so that the mitigation technique can be implemented successfully. The optical configuration proposed in this paper allows both a high speed inspection for HVM and a high accuracy defect locating function to be achieved on one inspection system.

  10. Evidence of printing blank-related defects on EUV masks missed by blank inspection

    NASA Astrophysics Data System (ADS)

    Jonckheere, Rik; Van den Heuvel, Dieter; Bret, Tristan; Hofmann, Thorsten; Magana, John; Aharonson, Israel; Meshulach, Doron; Hendrickx, Eric; Ronse, Kurt

    2011-03-01

    In this follow-up paper for our contribution at BACUS 2010, first evidence is shown that also the more advanced Lasertec M7360 has missed a few printing reticle defects caused by an imperfection of its EUV mirror, a so-called multilayer defect (ML-defect). This work continued to use a combination of blank inspection (BI), patterned mask inspection (PMI) and wafer inspection (WI) to find as many as possible printing defects on EUV reticles. The application of more advanced wafer inspection, combined with a separate repeater analysis for each of the multiple focus conditions used for exposure on the ASML Alpha Demo Tool (ADT) at IMEC, has allowed to increase the detectability of printing MLdefects. The latter uses the previous finding that ML-defects may have a through-focus printing behavior, i.e., they cause a different grade of CD impact on the pattern in their neighborhood, depending on the focus condition. Subsequent reticle review is used on the corresponding locations with both SEM (Secondary Electron Microscope) and AFM (Atomic Force Microscope). This review methodology has allowed achieving clear evidence of printing ML defects missed by this BI tool, despite of an unacceptable nuisance rate reported before. This is a next step in the investigation if it is possible to avoid actinic blank inspection (ABI) at all, the only presently known technique that is expected to be independent from the presence of a (residual) topography of the ML-defect at the top of the EUV mirror, in detecting those defects. This is considered an important asset of blank inspection, because the printability of a ML-defect on the EUV scanner and its detectability by ABI is determined by the distortion throughout the multilayer, not that at the surface.

  11. Improving the performance of the actinic inspection tool with an optimized alignment procedure

    SciTech Connect

    Mochi, I.; Goldberg, K.A.; Naulleau, P.; Huh, Sungmin

    2009-03-04

    Extreme ultraviolet (EUV) microscopy is an important tool for the investigation of the performance of EUV masks, for detecting the presence and the characteristics of defects, and for evaluating the effectiveness of defect repair techniques. Aerial image measurement bypasses the difficulties inherent to photoresist imaging and enables high data collection speed and flexibility. It provides reliable and quick feedback for the development of masks and lithography system modeling methods. We operate the SEMATECH Berkeley Actinic Inspection Tool (AIT), a EUV microscope installed at the Advanced Light Source at Lawrence Berkeley National Laboratory. The AIT is equipped with several high-magnification Fresnel zoneplate lenses, with various numerical aperture values, that enable it image the reflective mask surface with various resolution and magnification settings. Although the AIT has undergone significant recent improvements in terms of imaging resolution and illumination uniformity, there is still room for improvement. In the AIT, an off-axis zoneplate lens collects the light coming from the sample and an image of the sample is projected onto an EUV-sensitive CCD camera. The simplicity of the optical system is particularly helpful considering that the AIT alignment has to be performed every time that a sample or a zoneplate is replaced. The alignment is sensitive to several parameters such as the lens position and orientation, the illumination direction and the sample characteristics. Since the AIT works in high vacuum, there is no direct access to the optics or to the sample during the alignment and the measurements. For all these reasons the alignment procedures and feedback can be complex, and in some cases can reduce the overall data throughput of the system. In this paper we review the main strategies and procedures that have been developed for quick and reliable alignments, and we describe the performance improvements we have achieved, in terms of aberration

  12. Bridging the gaps between mask inspection/review systems and actual wafer printability using computational metrology and inspection (CMI) technologies

    NASA Astrophysics Data System (ADS)

    Pang, Linyong; Tolani, Vikram; Satake, Masaki; Hu, Peter; Peng, Danping; Liu, Tingyang; Chen, Dongxue; Gleason, Bob; Vacca, Anthony

    2012-11-01

    Computational techniques have become increasingly important to improve resolution of optical lithography. Advanced computational lithography technologies, such as inverse lithography (ILT) and source mask optimization (SMO), are needed to print the most challenging layers, such as contact and metal, at the 20nm node and beyond. In order to deploy SMO and ILT into production, improvements and upgrades of mask manufacturing technology are required. These include writing, inspection, defect review, and repair. For example, mask plane inspection detects defect at highest resolution, but does not correlate accurately with scanner images. Aerial plane mask inspection and AIMSTM produce images close to those of a scanner, but except fot the latest AIMS-32TM, it does not have the flexibility needed to capture all the characteristics of free-form illumination. Advanced Computational Inspection and Metrology provides solutions to many of these issues.

  13. Enabling inspection solutions for future mask technologies through the development of massively parallel E-Beam inspection

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    The new device architectures and materials being introduced for sub-10nm manufacturing, combined with the complexity of multiple patterning and the need for improved hotspot detection strategies, have pushed current wafer inspection technologies to their limits. In parallel, gaps in mask inspection capability are growing as new generations of mask technologies are developed to support these sub-10nm wafer manufacturing requirements. In particular, the challenges associated with nanoimprint and extreme ultraviolet (EUV) mask inspection require new strategies that enable fast inspection at high sensitivity. The tradeoffs between sensitivity and throughput for optical and e-beam inspection are well understood. Optical inspection offers the highest throughput and is the current workhorse of the industry for both wafer and mask inspection. E-beam inspection offers the highest sensitivity but has historically lacked the throughput required for widespread adoption in the manufacturing environment. It is unlikely that continued incremental improvements to either technology will meet tomorrow's requirements, and therefore a new inspection technology approach is required; one that combines the high-throughput performance of optical with the high-sensitivity capabilities of e-beam inspection. To support the industry in meeting these challenges SUNY Poly SEMATECH has evaluated disruptive technologies that can meet the requirements for high volume manufacturing (HVM), for both the wafer fab [1] and the mask shop. Highspeed massively parallel e-beam defect inspection has been identified as the leading candidate for addressing the key gaps limiting today's patterned defect inspection techniques. As of late 2014 SUNY Poly SEMATECH completed a review, system analysis, and proof of concept evaluation of multiple e-beam technologies for defect inspection. A champion approach has been identified based on a multibeam technology from Carl Zeiss. This paper includes a discussion on the

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    Industry data suggests that Mask Inspection represents the second biggest component of Mask Cost and Mask Turn Around Time (TAT). Ever decreasing defect size targets lead to more sensitive mask inspection across the chip, thus generating too many defects. Hence, more operator time is being spent in analyzing and disposition of defects. Also, the fact that multiple Mask Inspection Systems and Defect Analysis strategies would typically be in use in a Mask Shop or a Wafer Foundry further complicates the situation. In this scenario, there is a need for a versatile, user friendly and extensible Defect Analysis software that reduces operator analysis time and enables correct classification and disposition of mask defects by providing intuitive visual and analysis aids. We propose a new vendor-neutral defect analysis software, NxDAT, based on an open architecture. The open architecture of NxDAT makes it easily extensible to support defect analysis for mask inspection systems from different vendors. The capability to load results from mask inspection systems from different vendors either directly or through a common interface enables the functionality of establishing correlation between inspections carried out by mask inspection systems from different vendors. This capability of NxDAT enhances the effectiveness of defect analysis as it directly addresses the real-life scenario where multiple types of mask inspection systems from different vendors co-exist in mask shops or wafer foundries. The open architecture also potentially enables loading wafer inspection results as well as loading data from other related tools such as Review Tools, Repair Tools, CD-SEM tools etc, and correlating them with the corresponding mask inspection results. A unique concept of Plug-In interface to NxDAT further enhances the openness of the architecture of NxDAT by enabling end-users to add their own proprietary defect analysis and image processing algorithms. The plug-in interface makes it

  15. Comparative Evaluation of Mask Production CAR Development Process with Stepwise Defect Inspection

    NASA Astrophysics Data System (ADS)

    Jeong, Woo-Gun; Lee, Jung-Kwan; Park, Dong-Il; Park, Eu-Sang; Lee, Jong-Hwa; Seo, Sun-Kyu; Lee, Dong-Heok; Kim, Jin-Min; Choi, Sang-Soo; Jeong, Soo-Hong

    2002-12-01

    Chemically amplified resist (CAR) provides superior lithographic performance compared to traditional e-beam resists in production maskmaking. Parameters benefiting the most are contrast, resolution, and sensitivity. In spite of CAR's advantages, defect control and tighter 50KeV e-beam CAR process restrictions are significantly more critical thanks to smaller geometries, tighter CD specifications, and optical proximity correction (OPC) for 90nm node mask technology. Among defect root causes, resist development is considered to be the one of the most important steps because post-development residue can generate printable defects on finished masks. We investigated the CAR development process across different resist development methods, such as binary and fan-type nozzle spin spray, and puddle development. Several high density binary and embedded-attenuated phase shift masks (EAPSMs) with 70% clear area in the main pattern field were evaluated in an effort to identify and contain post-develop defects in a typical mask production flow. Development step process residue was examined at the after-develop inspection (ADI) step and scanning electron microscopy (SEM) was used for individual defect review. The KLA-Tencor SLF77 TeraStar inspection tool was used to inspect patterns after the development, Cr/MoSiON layer dry etch, and clean steps. The effectiveness of the various CAR development methods has been also studied following development, dry etch, and cleaning inspection by using identical binary and EAPSM masks from production. The mechanism and defect source during the stepwise process and inspections were scrutinized and discussed. Experimental results showed that stepwise process inspection was effective in identifying defects and their sources to prevent defects, and in optimizing each process step. It was found that CAR development and dry etch processes are the most important process steps to control defects in CAR-based mask production. Suggested optimized

  16. Comparison of critical dimension measurements of a mask inspection system with a CD-SEM

    NASA Astrophysics Data System (ADS)

    Heumann, Jan P.; Ullrich, Albrecht; Utzny, Clemens S.; Meusemann, Stefan; Kromer, Frank; Whittey, John M.; Garcia, Edgardo; Wagner, Mark; Schmidt, Norbert J.

    2012-11-01

    Critical dimension uniformity (CDU) is an important parameter for photomask and wafer manufacturing. In order to reduce long-range CD variation, compensation techniques for mask writers and scanners have been developed. Both techniques require mask CD measurements with high spatial sampling. Scanning electron microscopes (SEMs), which provide CD measurements at very high precision, cannot in practice provide the required spatial sampling due to their low speed. In contrast mask inspection systems, some of which have the ability to perform optical CD measurements with very high sampling frequencies, are an interesting alternative. In this paper we evaluate the CDU measurement results with those of a CD-SEM.

  17. EUV mask and wafer defectivity: strategy and evaluation for full die defect inspection

    NASA Astrophysics Data System (ADS)

    Bonam, Ravi; Tien, Hung-Yu; Chou, Acer; Meli, Luciana; Halle, Scott; Wu, Ivy; Huang, Xiaoxia; Lei, Chris; Kuan, Chiyan; Wang, Fei; Corliss, Daniel; Fang, Wei; Jau, Jack; Qi, Zhengqing John; Badger, Karen; Turley, Christina; Rankin, Jed

    2016-03-01

    Over the past few years numerous advancements in EUV Lithography have proven its feasibility of insertion into High Volume Manufacturing (HVM).1, 2 A lot of progress is made in the area of pellicle development but a commercially solution with related infrastructure is currently unavailable.3, 4 Due to current mask structure and unavailability of a pellicle, a comprehensive strategy to qualify (native defects) and monitor (adder defects) defectivity on mask and wafer is required for implementing EUV Lithography in High Volume Manufacturing. In this work, we assess multiple strategies for mask and wafer defect inspection including a two-fold solution to leverage resolution of e-beam inspection along with throughput of optical inspection are evaluated. Defect capture rates for inspections based on full-die, critical areas based on priority and hotspots based on design and prior inspection data are evaluated. Each strategy has merits and de-merits, particularly related to throughput, effective die coverage and computational overhead. A production ready EUV Exposure tool was utilized to perform exposures at the IBM EUV Center of Excellence in Albany, NY for EUV Lithography Development along with a fully automated line of EUV Mask Infrastructure tools. We will present strategies considered in this study and discuss respective results. The results from the study indicate very low transfer rate of defect detection events from optical mask inspection. They also suggest a hybrid strategy of utilizing both optical and e-beam inspection can provide a comprehensive defect detection which can be employed in High Volume Manufacturing.

  18. High-radiance LDP source: clean, reliable, and stable EUV source for mask inspection

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    High-throughput and -resolution actinic mask inspection tools are needed as EUVL begins to enter into volume production phase. To realize such inspection tools, a high-radiance EUV source is necessary. Ushio's laser-assisted discharge-produced plasma (LDP) source is able to meet industry's requirements in radiance, cleanliness, stability and reliability. Ushio's LDP source has shown the peak radiance at plasma of 180 W/mm2/sr and the area-averaged radiance in a 200-μm-diameter circle behind the debris mitigation system of 120 W/mm2/sr. A new version of the debris mitigation system is in testing phase. Its optical transmission was confirmed to be 73 %, which is 4 % lower than that of the previous version and therefore will be improved. Cleanliness of the system is evaluated by exposing Ru mirrors placed behind the debris mitigation system. Ru sputter rate was proven to be sufficiently low as 3~5 nm/Gpulse at 7 kHz, whereas frequency-dependent sputter rate was 1~3 nm/Gpulse at 5~9 kHz as previously reported. Sn deposition remained very low (< 0.05 nm) and did not grow over time. A new technique to suppress debris was tested and preliminary results were promising. Time-of-flight signal of fast ions was completely suppressed and Ru sputter rate of exposed mirrors at 3 kHz was approximately 1.3 nm/Gpulse, whereas the conventional mitigation system (new version) resulted in Ru sputter rate of 0.7 nm/Gpulse. This new technique also allows increasing the radiance efficiency by 30 %. Stability tests were done at several different discharge frequencies. Pulse energy stability was approximately 10 %. Dose energy stability dropped from approximately 2 % to 0.1 % when feedback control was activated. EUV emission position stability was studied at 3 kHz. Deviation of the plasma center of gravity was 6 μm, which is 3 % of plasma diameter and therefore considered to be negligible. Reliability tests were performed on both R and D and prototype machines and up to 200 hours of non

  19. AIMS D2DB simulation for DUV and EUV mask inspection

    NASA Astrophysics Data System (ADS)

    Peng, Danping; Li, Ying; Satake, Masaki; Hu, Peter; Chen, Jerry; Hsu, S. C.; Lai, Rick; Lin, C. S.; Tuo, Laurent C. C.

    2012-02-01

    AIMS™ Die-to-Die (D2D) is widely used in checking the wafer printability of mask defects for DUV lithography. Two AIMS images, a reference and a defect image, are captured and compared with differences larger than certain tolerances identified as real defects. Since two AIMS images are needed, and since AIMS system time is precious, it is desirable to save image search and capture time by simulating reference images from the OPC mask pattern and AIMS optics. This approach is called Die-to-Database (D2DB). Another reason that D2DB is desirable is in single die mask, where the reference image from another die does not exist. This paper presents our approach to simulate AIMS optics and mask 3D effects. Unlike OPC model, whose major concern is predicting printed CD, AIMS D2DB model must produce simulated images that match measured images across the image field. This requires a careful modeling of all effects that impact the final image quality. We present a vector-diffraction theory that is based on solid theoretical foundations and a general formulation of mask model that are applicable to both rigorous Maxwell solver and empirical model that can capture the mask 3D-effects. We demonstrated the validity of our approach by comparing our simulated image with AIMS machine measured images. We also briefly discuss the necessary changes needed to model EUV optics. Simulation is particularly useful while the industry waits for an actinic EUV-AIMS tool.

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

    SciTech Connect

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

    2008-02-01

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

  1. Technique for rapid at-wavelength inspection of extreme ultraviolet mask blanks

    SciTech Connect

    Spector, S. J.; White, D. L.; Tennant, D. M.; Ocola, L. E.; Novembre, A. E.; Peabody, M. L.; Wood, O. R. II

    1999-11-01

    We have developed two new methods for at-wavelength inspection of mask blanks for extreme-ultraviolet (EUV) lithography. In one method an EUV photoresist is applied directly to a mask blank which is then flood exposed with EUV light and partially developed. In the second method, the photoresist is applied to an EUV transparent membrane that is placed in close proximity to the mask and then exposed and developed. Both reflectivity defects and phase defects alter the exposure of the resist, resulting in mounds of resist at defect sites that can then be located by visual inspection. In the direct application method, a higher contrast resist was shown to increase the height of the mounds, thereby improving the sensitivity of the technique. In the membrane method, a holographic technique was used to reconstruct an image of the mask, revealing the presence of very small defects, approximately 0.2 {mu}m in size. The demonstrated clean transfer of phase and amplitude defects to resist features on a membrane will be important when flagging defects in an automatic inspection tool. (c) 1999 American Vacuum Society.

  2. Inspectability and printability of lines and spaces halftone masks for the advanced DRAM node

    NASA Astrophysics Data System (ADS)

    Dürr, Arndt C.; Gutjahr, Karsten; Heumann, Jan; Stengl, Martin; Katzwinkel, Frank; Frangen, Andreas; Witte, Thomas

    2006-10-01

    With decreasing pattern sizes the absolute size of acceptable pattern deviations decreases. For mask-makers a new technology requires a review, which mask design variations print on the wafer under production illumination conditions and whether these variations can be found reliably (100%) with the current inspection tools. As defect dispositioning is performed with an AIMS-tool, the critical AIMS values, above which a defect prints lithographically significant on the wafer, needs to be determined. In this paper we present a detailed sensitivity analysis for programmed defects on 2 different KLA 5xx tools employing the pixel P90 at various sensitivity settings in die-to-die transmitted mode. Comparing the inspection results with the wafer prints of the mask under disar illumination it could be shown that all critical design variations are reliably detected using a state-of-the-art tool setup. Furthermore, AIMS measurements on defects with increasing defect area of various defect categories were taken under the same illumination conditions as for the wafer prints. The measurements were evaluated in terms of AIMS intensity variation (AIV). It could be shown that the AIMS results exhibit a linear behavior if plotted against the square-root area (SRA) of the defects on the mask as obtained from mask SEM images. A consistent lower AIV value was derived for all defect categories.

  3. Toward defect guard-banding of EUV exposures by full chip optical wafer inspection of EUV mask defect adders

    NASA Astrophysics Data System (ADS)

    Halle, Scott D.; Meli, Luciana; Delancey, Robert; Vemareddy, Kaushik; Crispo, Gary; Bonam, Ravi; Burkhardt, Martin; Corliss, Daniel

    2015-03-01

    The detection of EUV mask adder defects has been investigated with an optical wafer defect inspection system employing a methodology termed Die-to-"golden" Virtual Reference Die (D2VRD). Both opaque and clear type mask absorber programmed defects were inspected and characterized over a range of defect sizes, down to (4x mask) 40 nm. The D2VRD inspection system was capable of identifying the corresponding wafer print defects down to the limit of the defect printability threshold at approximately 30 nm (1x wafer). The efficacy of the D2VRD scheme on full chip wafer inspection to suppress random process defects and identify real mask defects is demonstrated. Using defect repeater analysis and patch image classification of both the reference die and the scanned die enables the unambiguous identification of mask adder defects.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

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

    SciTech Connect

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

    2010-03-12

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

  7. High-throughput parallel SPM for metrology, defect, and mask inspection

    NASA Astrophysics Data System (ADS)

    Sadeghian, H.; Herfst, R. W.; van den Dool, T. C.; Crowcombe, W. E.; Winters, J.; Kramer, G. F. I. J.

    2014-10-01

    Scanning probe microscopy (SPM) is a promising candidate for accurate assessment of metrology and defects on wafers and masks, however it has traditionally been too slow for high-throughput applications, although recent developments have significantly pushed the speed of SPM [1,2]. In this paper we present new results obtained with our previously presented high-throughput parallel SPM system [3,4] that showcase two key advances that are required for a successful deployment of SPM in high-throughput metrology, defect and mask inspection. The first is a very fast (up to 40 lines/s) image acquisition and a comparison of the image quality as function of speed. Secondly, a fast approach method: measurements of the scan-head approaching the sample from 0.2 and 1.0 mm distance in under 1.4 and 6 seconds respectively.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  9. E-beam inspection of EUV mask defects: To etch or not to etch?

    NASA Astrophysics Data System (ADS)

    Bonam, Ravi; Tien, Hung-Yu; Park, Chanro; Halle, Scott; Wang, Fei; Corliss, Daniel; Fang, Wei; Jau, Jack

    2014-04-01

    EUV Lithography is aimed to be inserted into mainstream production for sub-20nm pattern fabrication. Unlike conventional optical lithography, frequent defectivity monitors (adders, repeaters etc.) are required in EUV lithography. Due to sub-20nm pattern and defect dimensions e-beam inspection of critical pattern areas is essential for yield monitor. In previous work we showed sub-10nm defect detection sensitivity1 on patterned resist wafers. In this work we report 8-10× improvement in scan rates of etched patterns compared to resist patterns without loss in defect detection sensitivity. We observed good etch transfer of sub-10nm resist features. A combination of smart scan strategies with improved etched pattern scan rates can further improve throughput of e-beam inspection. An EUV programmed defect mask with Line/Space, Contact patterns was used to evaluate printability of defects and defect detection (Die-Die and Die-Database) capability of the e-beam inspection tool. Defect inspection tool parameters such as averaging, threshold value were varied to assess its detection capability and were compared to previously obtained results on resist patterns.

  10. Sensitivity comparison of fast integrated die-to-die T+R pattern inspection, standard database inspection, and STARlight2 contamination mode for application in mask production

    NASA Astrophysics Data System (ADS)

    Schmalfuss, Heiko; Schulmeyer, Thomas; Heumann, Jan; Lang, Michael; Sier, Jean-Paul

    2007-10-01

    'Fast Integrated Die-to-Die T+R' pattern inspection (DDTR), reflected tritone database inspection (DBRt) and STARlight2 TM (SL2) contamination inspection are employed by mask makers in order to detect pattern defects and contamination defects on photomasks for in process inspection steps. In this paper we compare the detection capabilities of these modes on real production masks with a representative set of contamination and pattern defects. Currently, SL2 inspection is used to find contamination defects and die-to-die and die-to-database are used for pattern defects. In this paper we will show that the new introduced 'Fast Integrated Die-to-Die T+R' pattern inspection (DDTR)1 in combination with the DBRt can be used in production environment, instead of SL2 without any loss in the sensitivity. During the study, we collected and analyzed inspection data on critical layers such as lines & spaces and contact holes. Besides, performance of the modes on product plates characterization was done using a test mask with programmed defects.

  11. Enhancing productivity and sensitivity in mask production via a fast integrated die-to-database T+R inspection

    NASA Astrophysics Data System (ADS)

    Lu, Eric Haodong; Wu, David; Chen, Ellison; Badoni, Raj

    2007-10-01

    Inspection strategies of transmitted die-to-database pattern inspection (DBT), reflected die-to-database inspection (DBR) and STARlight2 TM (SL2) contamination inspection are employed by mask makers in order to detect pattern defects and contamination defects on photo-masks in process inspection steps and outgoing quality control (OQC). Currently, SL2 inspection is used to detect contamination defects while die-to-database inspections are used to detect pattern defects. However, such inspection strategies need two passes to detect both pattern defects and contamination defects. In this paper we introduce 'Fast Integrated Die-to-Database T+R' (Fast dbTR) and compare its detection capabilities and the productivity to conventional standard detection modes, such as, DBT, DBR and SL2. Programmed reticles and production reticles with pattern defects and contamination defects were used for comparative data collection. During the study, we collected and analyzed inspection data on critical layers such as lines & spaces and contact holes. Empirical data show that 'Fast dbTR' is able to cover the sensitivity required by DBT, DBR and SL2 to detect both pattern defects and contamination defects in one single scan without any loss of productivity in production runs.

  12. Impact of B4C capping layer for EUV mask on the sensitivity of patterned mask inspection using projection electron microscope

    NASA Astrophysics Data System (ADS)

    Iida, Susumu; Hirano, Ryoichi; Amano, Tsuyoshi; Watanabe, Hidehiro

    2014-10-01

    The inspection sensitivity of a patterned extreme ultraviolet (EUV) mask with B4C capped multilayer (ML) was investigated using a simulated projection electron microscope (PEM) image. Extrusion and intrusion defects with 16 nm in size were detected with their intensity of > 10 times the standard deviation of the background level on a half-pitch (hp) 64 nm line and space pattern. The defect detection sensitivity in this case was higher than that of Ru capped ML sample, and has a potential to meet the requirement for beyond 16 nm node generation from the standpoint of patterned mask inspection using the PEM technique. These results indicate that B4C capping layer besides its good durability has an advantage for high sensitivity of patterned mask inspection. The optimal condition of the incident beam energy was found to be 500 and 1000 eV for the samples of B4C capped ML and B4C buffered Ru capped ML, respectively. The sensitivity of defect detection was strongly affected by the difference of secondary electron emission coefficients (SEECs) between the absorber layer and capping layer. However, severely scattered electrons near the pattern edge become a source of noise and then they block the effect of large SEEC difference. Thus, the small incident beam energy was found to be preferable when the SEEC difference was relatively high.

  13. Mask pattern recovery by level set method based inverse inspection technology (IIT) and its application on defect auto disposition

    NASA Astrophysics Data System (ADS)

    Park, Jin-Hyung; Chung, Paul D. H.; Jeon, Chan-Uk; Cho, Han Ku; Pang, Linyong; Peng, Danping; Tolani, Vikram; Cecil, Tom; Kim, David; Baik, KiHo

    2009-10-01

    At the most advanced technology nodes, such as 32nm and 22nm, aggressive OPC and Sub-Resolution Assist Features (SRAFs) are required. However, their use results in significantly increased mask complexity, making mask defect disposition more challenging than ever. This paper describes how mask patterns can first be recovered from the inspection images by applying patented algorithms using Level Set Methods. The mask pattern recovery step is then followed by aerial/wafer image simulation, the results of which can be plugged into an automated mask defect disposition system based on aerial/wafer image. The disposition criteria are primarily based on wafer-plane CD variance. The system also connects to a post-OPC lithography verification tool that can provide gauges and CD specs, thereby enabling them to be used in mask defect disposition as well. Results on both programmed defects and production defects collected at Samsung mask shop are presented to show the accuracy and consistency of using the Level Set Methods and aerial/wafer image based automated mask disposition.

  14. Recent results from extreme ultraviolet lithography patterned mask inspection for 11 nm half-pitch generation using projection electron microscope system

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    Extreme ultraviolet lithography (EUVL) is a promising technique for 1X nm half-pitch (hp) generation lithography. The inspection of patterned EUVL masks is one of the main issues that must be addressed during mask fabrication for manufacture of devices with 11 nm hp feature sizes. We have already designed projection electron microscope (PEM) optics that have been integrated into a new inspection system called Model EBEYE-V30 (where "Model EBEYE" is an EBARA's model code) and this system seems quite promising for 16 nm hp generation EUVL patterned mask inspection. The defect inspection sensitivity of this system was evaluated via capture of an electron image that was generated at the mask by focusing the image through the projection optics onto a time-delay integration (TDI) image sensor. For increased throughput and higher defect detection sensitivity, a new electron-sensitive area image sensor with a high-speed data processing unit, a bright and stable electron source, and a simultaneous deflector for the image capture area that follows the mask scanning motion have been developed. Using a combination of synchronous deflection and mask scanning, the image can be integrated into both the fixed area image sensor and the TDI image sensor. We describe our experimental results for EUV patterned mask inspection using the above system. Elements have been developed for inspection tool integration and the designed specification has been verified. The system performance demonstrates the defect detectability required for 11 nm hp generation EUVL masks.

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

    SciTech Connect

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

    2008-05-26

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

  16. Microwave discharge plasma production with resonant cavity for EUV mask inspection tool

    NASA Astrophysics Data System (ADS)

    Tashima, Saya; Ohnishi, Masami; Hugrass, Waheed; Sugimoto, Keita; Sakaguchi, Masatugu; Osawa, Hodaka; Nishimura, Hiroaki; Matsukuma, Hiraku

    2015-12-01

    A microwave-discharge-produced plasma source was developed to generate 13.5 nm extreme ultraviolet (EUV) radiation for application as a mask inspection tool. The EUV radiation of a system with a high Q-factor (>3900) resonant cavity and a solid-state oscillator was studied. The gas pressure and microwave power dependences on the EUV radiation for transverse-magnetic mode TM010 and transverse-electric mode TE111 were determined. For the solid-state oscillator, the efficiency of the EUV radiation over the input power was 5.8 times higher than that for a magnetron. EUV radiation of 10 mW/(2πsr) was observed under a gas pressure of 5 Pa and microwave power of 400 W. We expect that more EUV power and a smaller plasma is generated when a magnetic field is applied to confirm the plasma and a facility is operated with an improved system to cool an entire cavity.

  17. Implementation of reflected light die-to-die inspection and ReviewSmart to improve 65nm DRAM mask fabrication

    NASA Astrophysics Data System (ADS)

    Kim, Do Young; Cho, Won Il; Park, Jin Hyung; Chung, Dong Hoon; Cha, Byung Chul; Choi, Seong Woon; Han, Woo Sung; Park, Ki Hun; Kim, Nam Wook; Hess, Carl; Ma, Weimin; Kim, David

    2005-11-01

    As the design rule continues to shrink towards 65nm size and beyond the defect criteria are becoming ever more challenging. Pattern fidelity and reticle defects that were once considered as insignificant or nuisance are now becoming significant yield impacting defects. The intent of this study is to utilize the new generation DUV system to compare Die-to-Die Reflected Light inspection and Die-to-Die Transmitted Light Inspection to increase defect detection for optimization of the 65nm node process. In addition, the ReviewSmart will be implemented to help categorically identify systematic tool and process variations and thus allowing user to expedite the learning process to develop a production worthy 65nm node mask process. The learning will be applied to Samsung's pattern inspection strategy, complementing Transmitted Light Inspection, on critical layers of 65 nm node to gain ability to find defects that adversely affect process window.

  18. Extreme ultraviolet mask defect inspection with a half pitch 16-nm node using simulated projection electron microscope images

    NASA Astrophysics Data System (ADS)

    Iida, Susumu; Amano, Tsuyoshi; Hirano, Ryoichi; Terasawa, Tsuneo; Watanabe, Hidehiro

    2013-04-01

    According to an International Technology Roadmap for Semiconductors (ITRS-2012) update, the sensitivity requirement for an extreme ultraviolet (EUV) mask pattern inspection system is to be less than 18 nm for half pitch (hp) 16-nm node devices. The inspection sensitivity of extrusion and intrusion defects on hp 64-nm line-and-space patterned EUV mask were investigated using simulated projection electron microscope (PEM) images. The obtained defect images showed that the optimization of current density and image processing techniques were essential for the detection of defects. Extrusion and intrusion defects 16 nm in size were detected on images formed by 3000 electrons per pixel. The landing energy also greatly influenced the defect detection efficiency. These influences were different for extrusion and intrusion defects. These results were in good agreement with experimentally obtained yield curves of the mask materials and the elevation angles of the defects. These results suggest that the PEM technique has a potential to detect 16-nm size defects on an hp 64-nm patterned EUV mask.

  19. Advanced mask inspection optical system (AMOS) using 198.5-nm wavelength for 65-nm (hp) node and beyond: system development and initial state D/D inspection performance

    NASA Astrophysics Data System (ADS)

    Tojo, Toru; Hirano, Ryoich; Tsuchiya, Hideo; Oaki, Junji; Nishizaka, Takeshi; Sanada, Yasushi; Matsuki, Kazuto; Isomura, Ikunao; Ogawa, Riki; Kobayashi, Noboru; Nakashima, Kazuhiro; Sugihara, Shinji; Inoue, Hiromu; Imai, Shinichi; Suzuki, Hitoshi; Sekine, Akihiko; Taya, Makoto; Miwa, Akemi; Yoshioka, Nobuyuki; Ohira, Katsumi; Chung, Dong-Hoon; Otaki, Masao

    2004-12-01

    A novel high-resolution mask inspection platform using DUV wavelength has been developed. This platform is designed to enable the defect inspection of high quality masks for 65nm node used in 193nm lithography. In this paper, newly developed optical system and its performance are reported. The system is operated at wavelength of 198.5nm, which wavelength is nearly equal to 193nm-ArF laser exposure tool. Some defect image data and defect inspection sensitivity due to simulation-base die-to-die (D/D) inspection are shown on standard programmed defect test mask. As an initial state D/D inspection performance, 20-60 nm defects are certified. System capabilities for 65nm node inspection and beyond are also discussed.

  20. Ezrin self-association involves binding of an N-terminal domain to a normally masked C-terminal domain that includes the F-actin binding site.

    PubMed Central

    Gary, R; Bretscher, A

    1995-01-01

    Ezrin is a membrane-cytoskeletal linking protein that is concentrated in actin-rich surface structures. It is closely related to the microvillar proteins radixin and moesin and to the tumor suppressor merlin/schwannomin. Cell extracts contain ezrin dimers and ezrin-moesin heterodimers in addition to monomers. Truncated ezrin fusion proteins were assayed by blot overlay to determine which regions mediate self-association. Here we report that ezrin self-association occurs by head-to-tail joining of distinct N-terminal and C-terminal domains. It is likely that these domains, termed N- and C-ERMADs (ezrin-radixin-moesin association domain), are responsible for homotypic and heterotypic associations among ERM family members. The N-ERMAD of ezrin resided within amino acids 1-296; deletion of 10 additional residues resulted in loss of activity. The C-ERMAD was mapped to the last 107 amino acids of ezrin, residues 479-585. The two residues at the C-terminus were required for activity, and the region from 530-585 was insufficient. The C-ERMAD was masked in the native monomer. Exposure of this domain required unfolding ezrin with sodium dodecyl sulfate or expressing the domain as part of a truncated protein. Intermolecular association could not occur unless the C-ERMAD had been made accessible to its N-terminal partner. It can be inferred that dimerization in vivo requires an activation step that exposes this masked domain. The conformationally inaccessible C-terminal region included the F-actin binding site, suggesting that this activity is likewise regulated by masking. Images PMID:7579708

  1. Impact of the phase defect structure on an actinic dark-field blank inspection signal and wafer printability

    NASA Astrophysics Data System (ADS)

    Amano, Tsuyoshi; Murachi, Tetsunori; Yamane, Takeshi; Arisawa, Yukiyasu; Terasawa, Tsuneo

    2012-03-01

    A variety of phase defects (PDs) such as programmed bump and pit PDs, and native bump and pit PDs were detected by a dark-field ABI (Actinic Blank Inspection) tool. Among the PDs, some of them seemed to grow and propagate in an angular direction, away from substrate surface as was found by a TEM analysis. This presentation reports on the influence of 3-D phase defect on wafer printability, and on defect detection signals of an ABI tool. The result shows that the impact of the inclination angle on printing performance was quite significant when the PDs were not covered with the absorber pattern. On the other hand, the defect detection signal intensity was negligibly small in the case where the inclination angle was less than 9 degrees. However, ABI with its high magnification optics can pinpoint the PD's actual location as defined by the EUV light, rather than the ones that are not so clearly define by the surface topography.

  2. Mask inspection microscopy with 13.2 nm table-top laser illumination

    SciTech Connect

    Brizuela, Fernando; Wang, Yong; Brewer, Courtney A.; Pedaci, Francesco; Chao, Weilun; Anderson, Erik H.; Liu, Yanwei; Goldberg, Kenneth A.; Naulleau, Patrick; Wachulak, Przemyslaw; Marconi, Mario C.; Attwood, David T.; Rocca, Jorge J.; Menoni, Carmen S.

    2008-10-14

    We report the demonstration of a reflection microscope that operates at 13.2-nm wavelength with a spatial resolution of 55 {+-} 3 nm. The microscope uses illumination from a table-top EUV laser to acquire aerial images of photolithography masks with a 20 second exposure time. The modulation transfer function of the optical system was characterized.

  3. 13.2 nm Table-Top Inspection Microscope for Extreme Ultraviolet Lithography Mask Defect Characterization

    SciTech Connect

    Brizuela, F.; Wang, Y.; Brewer, C.; Pedaci, F.; Chao, W.; Anderson, E.; Liu, Y.; Goldberg, K.; Naulleau, P.; Wachulak, P.; Marconi, M.; Attwood, D.; Rocca, J.; Menoni, C.

    2009-04-07

    We report on a reflection microscope that operates at 13.2-nm wavelength with a spatial resolution of 55{+-}3 nm. The microscope uses a table-top EUV laser to acquire images of photolithography masks in 20 seconds.

  4. Process window impact of progressive mask defects: its inspection and disposition techniques (go/no-go criteria) via a lithographic detector

    NASA Astrophysics Data System (ADS)

    Huang, Jerry; Peng, Lan-Hsin; Chu, Chih-Wei; Bhattacharyya, Kaustuve; Eynon, Ben; Mirzaagha, Farzin; Dibiase, Tony; Son, Kong; Cheng, Jackie; Chen, Ellison; Wang, Den

    2005-11-01

    Progressive mask defect problem is an industry wide mask reliability issue. During the start of this problem when the defects on masks are just forming and are still non-critical, it is possible to continue to run such a problem mask in production with relatively low risk of yield impact. But when the defects approach more critical state, a decision needs to be made whether to pull the mask out of production to send for clean (repair). As this problem increases on the high-end masks running DUV lithography where masks are expensive, it is in the interest of the fab to sustain these problem masks in production as long as possible and take these out of production only when absolutely necessary; i.e., when the defects have reached such a critical condition on these masks that it will impact the process window. During the course of this technical work, investigation has been done towards understanding the impact of such small progressive defects on process window. It was seen that a small growing defect may not print at the best focus exposure condition, but it can still influence the process window and can shrink it significantly. With the help of a high-resolution direct reticle inspection, early detection of these defects is possible, but fabs are still searching for a way to disposition (make a go / no-go decision) on these defective masks. But it is not an easy task as the impact of these defects will depend on not only their size, but also on their transmission and MEEF. A lithographic detector has been evaluated to see if this can predict the criticality of such progressive mask defects.

  5. Your worst nightmare: inspection of aggressive OPC on 14nm masks with emphasis on defect sensitivity and wafer defect print predictability

    NASA Astrophysics Data System (ADS)

    Badger, Karen D.; Hibbs, Michael; Rankin, Jed; Seki, Kazunori; Stobert, Ian; Dechene, Daniel J.; Bleiman, Ben; Ghosal, Mini; Broadbent, William; Redding, Vincent

    2013-09-01

    To prevent catastrophic failures during wafer manufacturing, mask manufacturers employ sophisticated reticle inspection systems to examine every image on every reticle to identify defects. These advanced systems inspect at resolutions typically 3x higher at the reticle-plane than advanced wafer scanners; thus enabling them to detect the small defects necessary to ensure reticle quality. The most thorough inspection is done using a reticle-to-database comparison that ensures the reticle pattern matches the design pattern. For high defect sensitivity, the database must be carefully modeled to exactly match the reticle pattern. Further, sub-resolution OPC shapes are often at the limit of the mask manufacturing process, which adds subtle variations on such shapes across the reticle. These modeling errors and process variations can cause high numbers of unwanted detections, thereby limiting inspection system defect detection sensitivity.[1] OPC designs are expected to become more aggressive for future generations and may stress the performance of current reticle inspection systems. To systematically assess the capability of various inspection approaches and identify needed areas for improvement, a new "Nightmare" test reticle has been designed by IBM. The test reticle contains various sizes and shapes of sub-resolution features that might appear on reticle generations from today's 22nm to future 7nm. It also contains programmed defects to assess defect detection capability of current and future generation inspection systems. This paper will discuss the design of the "Nightmare" test reticle, and the inspection results of the current generation reticle inspection methods with emphasis on both inspectability and defect sensitivity. The subresolution features will be ranked according to importance for advanced OPC design. The reticle will also be evaluated using wafer print simulation so lithographic impact of features and defects can be measured and compared against

  6. Design and Evaluation of System Configurations for an EUV Mask Inspection Microscope

    SciTech Connect

    Barty, A; Taylor, J S; Hudyma, R; Spiller, E

    2002-08-20

    This document is the third sub-report of the EUV AIM design study being conducted at LLNL on behalf of International Sematech (ISMT). The purpose of this study as identified in section 1.2 of the statement of work is to research the basic user requirements of an actinic defect characterization tool, potential design configurations and top-level specifications. The objectives of this design study specifically identified in section 1.3 of the statement of work were to: (1) Determine the user requirements of an actinic defect characterization tool; (2) Determine if an EUV AIM tool is an appropriate platform for actinic defect characterization; (3) Determine possible design configurations and top-level performance specifications; (4) Identify potential technical issues and risks of different technical approaches; (5) Provide estimates of cost relating to different technical approaches; and (6) Provide simulated performance for key subsystems and the entire system. The sub-sections of the study to be addressed were accordingly defined in the statement of work as being: (1) Formulation of top-level specifications; (2) Identification of system configurations suitable for meeting the top-level specifications; (3) Preliminary design of imaging systems; (4) Preliminary design of illumination systems; (5) Prediction and comparison of performance through aerial image calculation; (6) Identification of sub-system requirements; (7) Identification of potential vendors; (8) Estimation of system cost; (9) Identification of technical issues; and (10) Definition of technology transfer or development required. Points 1 and 2 have already been addressed in previous reports to ISMT. This document addresses points 3 to 7, and 9 to 10 of the above list--formulation of a preliminary design of the imaging and illumination systems and the evaluation and comparison of potential designs through aerial image analysis. As such this report should be read in conjunction with and in the context of

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

    SciTech Connect

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

    2007-08-01

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

  8. Shuttle mask floorplanning

    NASA Astrophysics Data System (ADS)

    Xu, Gang; Tian, Ruiqi; Wong, Martin D.; Reich, Alfred J.

    2003-12-01

    A shuttle mask has different chips on the same mask. The chips are not electrically connected. Alliance and foundry customers can utilize shuttle masks to share the rising cost of mask and wafer manufacturing. This paper studies the shuttle mask floorplan problem, which is formulated as a rectangle-packing problem with constraints of final die sawing strategy and die-to-die mask inspection. For our formulation, we offer a "merging" method that reduces the problem to an unconstrained slicing floorplan problem. Excellent results are obtained from the experiment with real industry data. We also study a "general" method and discuss the reason why it does not work very well.

  9. Thorough characterization of a EUV mask

    SciTech Connect

    Mizuno, H.; McIntyre, G.; Koay, C.-W.; Burkhardt, M.; He, L.; Hartley, J.; Johnson, C.; Raghunathan, S.; Goldberg, K.; Mochi, I.; La Fontaine, B.; Wood, O.

    2009-06-25

    We reported that we were successful in our 45nm technology node device demonstration in February 2008 and 22nm node technology node device patterning in February 2009 using ASML's Alpha Demo Tool (ADT). In order to insert extreme ultraviolet (EUV) lithography at the 15nm technology node and beyond, we have thoroughly characterized one EUV mask, a so-called NOVACD mask. In this paper, we report on three topics, The first topic is an analysis of line edge roughness (LER) using a mask Scanning Electron Microscope (SEM), an Atomic Force Microscope (AFM) and the Actinic Inspection Tool (AIT) to compare resist images printed with the ASML ADT. The results of the analysis show a good correlation between the mask AFM and the mask SEM measurements, However, the resist printing results for the isolated space patterns are slightly different. The cause ofthis discrepancy may be resist blur, image log slope and SEM image quality and so on. The second topic is an analysis of mask topography using an AFM and relative reflectivity of mirror and absorber surface using the AIT, The AFM data show 6 and 7 angstrom rms roughness for mirror and absorber, respectively. The reflectivity measurements show that the mirror reflects EUV light about 20 times higher than absorber. The last topic is an analysis of a 32nm technology node SRAM cell which includes a comparison of mask SEM image, AIT image, resist image and simulation results. The ADT images of the SRAM pattern were of high quality even though the mask patters were not corrected for OPC or any EUV-specific effects. Image simulation results were in good agreement with the printing results.

  10. Mask degradation monitoring with aerial mask inspector

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  11. Actinic Keratosis

    MedlinePlus

    ... rashes clinical tools newsletter | contact Share | Actinic Keratosis (Solar Keratosis) Information for adults A A A Actinic ... the touch. Overview Actinic keratoses, also known as solar keratoses, are small rough or scaly areas of ...

  12. Carbon contamination of extreme ultraviolet (EUV) mask and its effect on imaging

    SciTech Connect

    Fan, Yu-Jen; Yankulin, Leonid; Antohe, Alin; Garg, Rashi; Thomas, Petros; Mbanaso, Chimaobi; Wuest, Andreas; Goodwin, Frank; Huh, Sungmin; Naulleau, Patrick; Goldlberg, Kenneth; Mochi, Iacopo; Denbeaux, Gregory

    2009-02-02

    Carbon contamination of extreme ultraviolet (EUV) masks and its effect on imaging is a significant issue due to lowered throughput and potential effects on imaging performance. In this work, a series of carbon contamination experiments were performed on a patterned EUV mask. Contaminated features were then inspected with a reticle scanning electron microscope (SEM) and printed with the SEMA TECH Berkeley Microfield-Exposure tool (MET) [1]. In addition, the mask was analyzed using the SEMA TECH Berkeley Actinic-Inspection tool (AIT) [2] to determine the effect of carbon contamination on the absorbing features and printing performance. To understand the contamination topography, simulations were performed based on calculated aerial images and resist parameters. With the knowledge of the topography, simulations were then used to predict the effect of other thicknesses of the contamination layer, as well as the imaging performance on printed features.

  13. Evaluating EUV mask pattern imaging with two EUV microscopes

    SciTech Connect

    Goldberg, Kenneth A.; Takase, Kei; Naulleau, Patrick P.; Han, Hakseung; Barty, Anton; Kinoshita, Hiroo; Hamamoto, Kazuhiro

    2008-02-26

    Aerial image measurement plays a key role in the development of patterned reticles for each generation of lithography. Studying the field transmitted (reflected) from EUV masks provides detailed information about potential disruptions caused by mask defects, and the performance of defect repair strategies, without the complications of photoresist imaging. Furthermore, by measuring the continuously varying intensity distribution instead of a thresholded, binary resist image, aerial image measurement can be used as feedback to improve mask and lithography system modeling methods. Interest in EUV, at-wavelength, aerial image measurement lead to the creation of several research tools worldwide. These tools are used in advanced mask development work, and in the evaluation of the need for commercial at-wavelength inspection tools. They describe performance measurements of two such tools, inspecting the same EUV mask in a series of benchmarking tests that includes brightfield and darkfield patterns. One tool is the SEMATECH Berkeley Actinic Inspection Tool (AIT) operating on a bending magnet beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The AIT features an EUV Fresnel zoneplate microscope that emulates the numerical aperture of a 0.25-NA stepper, and projects the aerial image directly onto a CCD camera, with 700x magnification. The second tool is an EUV microscope (EUVM) operating at the NewSUBARU synchrotron in Hyogo, Japan. The NewSUBARU tool projects the aerial image using a reflective, 30x Schwarzschild objective lens, followed by a 10-200x x-ray zooming tube. The illumination conditions and the imaging etendue are different for the two tools. The benchmarking measurements were used to determine many imaging and performance properties of the tools, including resolution, modulation transfer function (MTF), aberration magnitude, aberration field-dependence (including focal-plane tilt), illumination uniformity, line-edge roughness, and flare

  14. Shearography for Non-destructive Inspection with applications to BAT Mask Tile Adhesive Bonding and Specular Surface Honeycomb Panels

    NASA Technical Reports Server (NTRS)

    Lysak, Daniel B.

    2003-01-01

    The applicability of shearography techniques for non-destructive evaluation in two unique application areas is examined. In the first application, shearography is used to evaluate the quality of adhesive bonds holding lead tiles to the B.4T gamma ray mask for the NASA Swift program. Using a vibration excitation, the more poorly bonded tiles are readily identifiable in the shearography image. A quantitative analysis is presented that compares the shearography results with a destructive pull test measuring the force at bond failure. The second application is to evaluate the bonding between the skin and core of a honeycomb structure with a specular (mirror-like) surface. In standard shearography techniques, the object under test must have a diffuse surface to generate the speckle patterns in laser light, which are then sheared. A novel configuration using the specular surface as a mirror to image speckles from a diffuser is presented, opening up the use of shearography to a new class of objects that could not have been examined with the traditional approach. This new technique readily identifies large scale bond failures in the panel, demonstrating the validity of this approach.

  15. [Actinic Keratosis].

    PubMed

    Dejaco, D; Hauser, U; Zelger, B; Riechelmann, H

    2015-07-01

    Actinic keratosis is a cutaneous lesion characterized by proliferation of atypical epidermal keratinocytes due to prolonged exposure to exogenous factors such as ultraviolet radiation. AKs are in-situ-squamous cell carcinomas (PEC) of the skin. AK typically presents as erythematous, scaly patch or papule (classic AK), occasionally as thick, adherent scale on an erythematous base. Mostly fair-skinned adults are affected. AKs typically occur in areas of frequent sun exposure (balding scalp, face, "H-region", lateral neck, décolleté, dorsum of the hand and lower extremities). Actinic Cheilitis is the term used for AKs appearing on the lips. The diagnosis of AK is based on clinical examination including inspection and palpation. The typical palpable rough surface of AK often precedes a visible lesion. Dermoscopy may provide additional information. If diagnosis is uncertain and invasion suspected, biopsy and histopathologic evaluation should be performed. The potential for progression to invasive PECs mandates therapeutic intervention. Treatment options include topical and systemic therapies. Topical therapies are classified into physical, medical and combined physical-chemical approaches and a sequential combination of treatment modalities is possible. Topical-physical cryotherapy is the treatment of choice for isolated, non-hypertrophic AK. Topical-medical treatment, e. g. 5-fluoruracil (5FU) cream or Imiquomod or Ingenolmebutat application is used for multiple, non-hypertrophic AKs. For hypertrophic AKs, a dehorning pretreatment with salicinated vaseline is recommended. Isolated hypertrophic AKs often need cryotherapy with prolonged freezing time or several consecutive applications. Sequentially combined approaches are recommended for multiple, hypertrophic AKs. Photodynamic therapy (PDT) as example for a combined physical-chemical approach is an established treatment for multiple, non-hypertrophic and hypertrophic AKs. Prevention includes avoidance of sun and

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

    SciTech Connect

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

    2015-03-01

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

  17. Actinic keratosis

    MedlinePlus

    Solar keratosis; Sun-induced skin changes - keratosis; Keratosis - actinic (solar) ... Actinic keratosis is caused by exposure to sunlight. You are more likely to develop it if you: Have fair skin, blue or green eyes, or blond or red hair Had a ...

  18. Mask manufacturability improvement by MRC

    NASA Astrophysics Data System (ADS)

    Balasinski, A.; Coburn, D.; Buck, P.

    2007-10-01

    Mask data which can not be properly resolved by the mask writing tools, such as sub(resolution (reticle-scale) features or singularities can interfere with design intent or manufacturing capabilities in the absence of design guidelines or formal verification procedures. As a consequence, mask writing tools may introduce defects to device or metrology structures by snapping geometries to grid or misrepresenting process based sizing. To reduce the visibility of these defects by detuning inspection tools to release the mask with non-resolvable data in the production cycle or by waiving minimum CD rules compromises high fidelity of die pattern transfer to wafer. Driven by poor data quality, mask tool would provide degraded resolution without contextual analysis, such as correlations to the overlying and underlying mask layers and without regard to device models. The key reasons for this situation are arbitrary layout of technology structures and design layout-to-mask post-processing for OPC and fill pattern for which design has no intention or knowledge to intervene. The post-processing of mask data to eliminate errors effectively detaches design responsibility from the mask shop actions and may have other detrimental effects on the production cycle such as iterative defect analysis and long write times due to the large polygon count. In this work we propose mask rule check based on the principles to which the masks are being written and inspected. Running this mandatory rule set should reduce the product cycletime, benefit the cost and improve mask quality and reproduction of design intent. It feeds the prospective mask information back to the layout time making it possible to make design adjustments in the interest of pattern fidelity and device parameters.

  19. Actinic Cheilitis

    MedlinePlus

    ... is a precancerous condition related to cumulative lifetime sun exposure. The lower lip is most often affected. Individuals ... Wearing barrier clothing (eg, wide-brimmed hats) and sunscreen-containing lip balms can aid in preventing actinic ...

  20. Mask qualification strategies in a wafer fab

    NASA Astrophysics Data System (ADS)

    Jaehnert, Carmen; Kunowski, Angela

    2007-02-01

    Having consistent high quality photo masks is one of the key factors in lithography in the wafer fab. Combined with stable exposure- and resist processes, it ensures yield increases in production and fast learning cycles for technology development and design evaluation. Preventive controlling of incoming masks and quality monitoring while using the mask in production is essential for the fab to avoid yield loss or technical problems caused by mask issues, which eventually result in delivery problems to the customer. In this paper an overview of the procedures used for mask qualification and production release, for both logic and DRAM, at Infineon Dresden is presented. Incoming qualification procedures, such as specification checks, incoming inspection, and inline litho process window evaluation, are described here. Pinching and electrical tests, including compatibility tests for mask copies for high volume products on optimized litho processes, are also explained. To avoid mask degradation over lifetime, re-inspection checks are done for re-qualification while using the mask in production. The necessity of mask incoming inspection and re-qualification, due to the repeater printing from either the processing defects of the original mask or degrading defects of being used in the fab (i.e. haze, ESD, and moving particles, etc.), is demonstrated. The need and impact of tight mask specifications, such as CD uniformity signatures and corresponding electrical results, are shown with examples of mask-wafer CD correlation.

  1. [Masked depression].

    PubMed

    Preradović, M; Griva, D; Eror, S

    1991-01-01

    The study comprised 25 patients with masked depression and 30 patients with endogenous depression. According to the general characteristics both groups were homogenous and accordingly, comparable. Together with clinical evaluation of depressive syndrome, psychological management was applied. Rorschach test, Thematic Apperception Test and Minnesota Multiphasic Personality Inventory were used in the study. In the clinical picture of masked depressions somatovegetative disorders dominated and depressive behavior in endogenous depression. The frequence of suicid does not differ between patients with masked and endogenous depression.

  2. Mask Blank Defect Detection

    SciTech Connect

    Johnson, M A; Sommargren, G E

    2000-02-04

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

  3. Actinic Keratoses

    PubMed Central

    Brown, Marc D.

    2009-01-01

    Actinic keratoses are common intra-epidermal neoplasms that lie on a continuum with squamous cell carcinoma. Tightly linked to ultraviolet irradiation, they occur in areas of chronic sun exposure, and early treatment of these lesions may prevent their progression to invasive disease. A large variety of effective treatment modalities exist, and the optimal therapeutic choice is dependent on a variety of patient- and physician-associated variables. Many established and more recent approaches are discussed in this review with a focus on efficacy and administration techniques. Several previously experimental options, such as imiquimod and photodynamic therapy, have become incorporated as first-line options for the treatment of actinic keratoses, while combination treatment strategies have been gaining in popularity. The goal of all therapies is to ultimately limit the morbidity and mortality of squamous cell carcinoma. (J Clin Aesthetic Dermatol. 2009;2(7):43–48.) PMID:20729970

  4. SEMATECH EUVL mask program status

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

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

    SciTech Connect

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

    2015-03-16

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

  6. Coatings on reflective mask substrates

    DOEpatents

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

    2002-01-01

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

  7. Quantitative evaluation of mask phase defects from through-focus EUV aerial images

    SciTech Connect

    Mochi, Iacopo; Yamazoe, Kenji; Neureuther, Andrew; Goldberg, Kenneth A.

    2011-02-21

    Mask defects inspection and imaging is one of the most important issues for any pattern transfer lithography technology. This is especially true for EUV lithography where the wavelength-specific properties of masks and defects necessitate actinic inspection for a faithful prediction of defect printability and repair performance. In this paper we will present a technique to obtain a quantitative characterization of mask phase defects from EUV aerial images. We apply this technique to measure the aerial image phase of native defects on a blank mask, measured with the SEMATECH Berkeley Actinic Inspection Tool (AIT) an EUV zoneplate microscope that operates at Lawrence Berkeley National Laboratory. The measured phase is compared with predictions made from AFM top-surface measurements of those defects. While amplitude defects are usually easy to recognize and quantify with standard inspection techniques like scanning electron microscopy (SEM), defects or structures that have a phase component can be much more challenging to inspect. A phase defect can originate from the substrate or from any level of the multilayer. In both cases its effect on the reflected field is not directly related to the local topography of the mask surface, but depends on the deformation of the multilayer structure. Using the AIT, we have previously showed that EUV inspection provides a faithful and reliable way to predict the appearance of mask defect on the printed wafer; but to obtain a complete characterization of the defect we need to evaluate quantitatively its phase component. While aerial imaging doesn't provide a direct measurement of the phase of the object, this information is encoded in the through focus evolution of the image intensity distribution. Recently we developed a technique that allows us to extract the complex amplitude of EUV mask defects using two aerial images from different focal planes. The method for the phase reconstruction is derived from the Gerchberg-Saxton (GS

  8. Masks for extreme ultraviolet lithography

    SciTech Connect

    Cardinale, G; Goldsmith, J; Kearney, P A; Larson, C; Moore, C E; Prisbrey, S; Tong, W; Vernon, S P; Weber, F; Yan, P-Y

    1998-09-01

    In extreme ultraviolet lithography (EUVL), the technology specific requirements on the mask are a direct consequence of the utilization of radiation in the spectral region between 10 and 15 nm. At these wavelengths, all condensed materials are highly absorbing and efficient radiation transport mandates the use of all-reflective optical systems. Reflectivity is achieved with resonant, wavelength-matched multilayer (ML) coatings on all of the optical surfaces - including the mask. The EUV mask has a unique architecture - it consists of a substrate with a highly reflective ML coating (the mask blank) that is subsequently over-coated with a patterned absorber layer (the mask). Particulate contamination on the EUVL mask surface, errors in absorber definition and defects in the ML coating all have the potential to print in the lithographic process. While highly developed technologies exist for repair of the absorber layer, no viable strategy for the repair of ML coating defects has been identified. In this paper the state-of-the-art in ML deposition technology, optical inspection of EUVL mask blank defects and candidate absorber patterning approaches are reviewed.

  9. EUVL mask performance and optimization

    NASA Astrophysics Data System (ADS)

    Davydova, Natalia; de Kruif, Robert; van Setten, Eelco; Connolly, Brid; Mehagnoul, Karolien; Zimmerman, John; Harned, Noreen; Kalk, Franklin

    2012-02-01

    EUV lithography requires an exposure system with complex reflective optics and an equally complex EUV dedicated reflective mask. The required high level of reflectivity is obtained by using multilayers. The multilayer of the system optics and the mask are tuned to each other. The mask is equipped with an additional patterned absorber layer. The EUV mask is an optical element with many parameters that contribute to the final image and overlay quality on the wafer and the productivity of the system. Several of these parameters can be tuned for optimal overlay, imaging and productivity results. This should be done with care because of possible interaction between parameters. We will present an overview of the EUV mask contributors to the imaging, overlay and productivity performance for the 27 nm node and below, such as multilayer and absorber stack composition, reflectivity and reflectivity uniformity. These parameters will be reviewed in the context of real-life scanner parameters for the ASML NXE:3100 and NXE:3300 system configurations. The predictions will be compared to actual exposure results on NXE:3100 systems (NA=0.25) for various masks and extrapolated to the NXE:3300 (NA=0.33). In particular, we will present extensive multilayer and absorber actinic spectral reflectance measurements of a state-ofthe art EUV mask over a range of incidence angles corresponding to an NA of 0.33 at multiple positions within the image field. The ML measurements allow calibrating ML stack for imaging simulations. It allows also the estimation of mask-induced apodization effects having impact on overlay. In general, the reflectivity measurements will give detailed variations over the image field of mask parameters such as ML centroid wavelength and absorber reflectivity which contribute to CD uniformity. Such a relation will be established by means of rigorous full stack imaging simulations taking into account optical properties of the coming NXE:3300 system. Based on this

  10. Computational techniques for determining printability of real defects in EUV mask pilot line

    NASA Astrophysics Data System (ADS)

    Morgan, Paul; Rost, Daniel; Price, Daniel; Li, Ying; Peng, Daniel; Chen, Dongxue; Hu, Peter; Corcoran, Noel; Son, Donghwan; Yonenaga, Dean; Tolani, Vikram

    2014-04-01

    With EUV lithography on the ITRS roadmap for sub-2X half-pitch patterning, it has become increasingly essential to ramp up efforts in being able to manufacture defect-free reticles or at least ones with minimal defects initially. For this purpose, much of the focus in recent years has been in finding ways to adequately detect, characterize, and reduce defects on both EUV blanks and patterned masks. For detection purposes, the current high-resolution DUV or e-beam inspection platforms are being extended to inspect EUV blanks and patterned masks but being non-actinic, make it very challenging to assess the real impact of the detected defects on EUV plane. Even with the realization of the EUV beta AIMS™ aerial-image based metrology in 2014-2015, the exact nature of each critical defect needs to be determined in order to be able to come up with an appropriate repair strategy. In this paper, we demonstrate the application of computational techniques to non-actinic supplemental metrology data collected on EUV mask defects to effectively determine the nature and also predict printability of these defects. The fundamental EUV simulation engine used in this approach is the EUV Defect Printability Simulator (DPS), which uses simulation and modeling methods designed specifically for the individual EUV mask components, and achieves runtimes several orders of magnitude faster than rigorous FDTD and RCWA methods while maintaining adequate accuracy. The EUV DPS simulator is then coupled with supplemental inspection and metrology measurements of real defects to effectively predict wafer printability of these defects. Several sources of such supplementary data are explored here, and may sometimes be dependent on the actual nature of defect. These sources include AFM height-profile data, SEM top-down images, and 193nm high-NA inspection images of single or multiple focus plane capture. From each of these supplemental data sources, the mask pattern and defect information is first

  11. Mask-LMC: lithographic simulation and defect detection from high-resolution mask images

    NASA Astrophysics Data System (ADS)

    Chen, George; Wiley, James N.; Wang, Jen-Shiang; Howell, Rafael C.; Bai, Shufeng; Chen, Yi-Fan; Chen, Frank; Cao, Yu; Takigawa, Tadahiro; Kurosawa, Terunobu; Tsuchiya, Hideo; Usuda, Kinya; Tokita, Masakazu; Ozaki, Fumio; Kikuiri, Nobutaka; Tsuji, Yoshitake

    2009-04-01

    We report the development of Mask-LMC for defect printability evaluation from sub-200nm wavelength mask inspection images. Both transmitted and reflected images are utilized, and both die-to-die and die-to-database inspection modes are supported. The first step of the process is to recover the patterns on the mask from high resolution T and R images by de-convolving inspection optical effects. This step uses a mask reconstruction model, which is based on rigorous Hopkins-modeling of the inspection optics, and is pre-determined before the full mask inspection. After mask reconstruction, wafer scanner optics and wafer resist simulations are performed on the reconstructed mask, with a wafer lithography model. This step leverages Brion's industry-proven, hardware-accelerated LMC (Lithography Manufacturability Check) technology1. Existing litho process models that are in use for Brion's OPC+ and verification products may be used for this simulation. In the final step, special detectors are used to compare simulation results on the reference and defect dice. We have developed detectors for contact CD, contact area, line and space CD, and edge placement errors. The detection result has been validated with AIMSTM.

  12. Clay Mask Workshop

    ERIC Educational Resources Information Center

    Gamble, David L.

    2012-01-01

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

  13. Development of mask-DFM system MiLE load estimation of mask manufacturing

    NASA Astrophysics Data System (ADS)

    Nagamura, Yoshikazu; Hosono, Kunihiro; Narukawa, Shogo; Mohri, Hiroshi; Hayashi, Naoya; Kato, Masahiro; Kawase, Hidemichi

    2007-10-01

    Load of photomask manufacturing for the most advanced semiconductor devices is increasing due to the complexity of mask layouts caused by highly accurate RET or OPC, tight specification for 2D/3D mask structures, and requirements of quick deliveries. The mask cost becomes a concern of mask users especially in SoC businesses because the number of masks required throughout the wafer process is almost the same for each product regardless of the variety in production volume when a unified platform is applied to the designs. Shares of mask cost within total production cost cannot be ignored especially in small volume SoC products. DFM (design for manufacturing) is inevitable in a mask level as well as in a wafer level to solve the cost problem. "Mask-DFM" is a method to decrease the burden of mask manufacturing and to improve the yield and quality of masks, not only by modification of mask pattern layouts (design) but also all other things including utilization of designer's intents. We have developed our Mask-DFM system called "MiLE", that calculates mask-manufacturing workload through layout analyses combining information of mask configuration, and visualizes the consequence of Mask-DFM efforts. "MiLE (Mask manufacturIng Load Estimation)" calculates a relative index which represents the mask manufacturing workload determined by factors of 1) EB writing, 2) defect inspection/repair, 3) materials and processes and 4) specification. All the factors are computed before tape-outs for mask making in the system by the following methods. To estimate EB writing time, we applied high-throughput simulator and counted the number of "shot", minimum figure unit in EB writing, by using post-OPC layout data. Mask layout that caused troubles and extra load in mask inspection or repair was specified from MRC (mask rule checking) of the same post-OPC data. Additional layout analysis perceives designer's intents that are described in the layout data and these are reflected in the

  14. Smoke Mask

    NASA Technical Reports Server (NTRS)

    2003-01-01

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

  15. Sensing actin dynamics: Structural basis for G-actin-sensitive nuclear import of MAL

    SciTech Connect

    Hirano, Hidemi; Matsuura, Yoshiyuki

    2011-10-22

    Highlights: {yields} MAL has a bipartite NLS that binds to Imp{alpha} in an extended conformation. {yields} Mutational analyses verified the functional significance of MAL-Imp{alpha} interactions. {yields} Induced folding and NLS-masking by G-actins inhibit nuclear import of MAL. -- Abstract: The coordination of cytoskeletal actin dynamics with gene expression reprogramming is emerging as a crucial mechanism to control diverse cellular processes, including cell migration, differentiation and neuronal circuit assembly. The actin-binding transcriptional coactivator MAL (also known as MRTF-A/MKL1/BSAC) senses G-actin concentration and transduces Rho GTPase signals to serum response factor (SRF). MAL rapidly shuttles between the cytoplasm and the nucleus in unstimulated cells but Rho-induced depletion of G-actin leads to MAL nuclear accumulation and activation of transcription of SRF:MAL-target genes. Although the molecular and structural basis of actin-regulated nucleocytoplasmic shuttling of MAL is not understood fully, it is proposed that nuclear import of MAL is mediated by importin {alpha}/{beta} heterodimer, and that G-actin competes with importin {alpha}/{beta} for the binding to MAL. Here we present structural, biochemical and cell biological evidence that MAL has a classical bipartite nuclear localization signal (NLS) in the N-terminal 'RPEL' domain containing Arg-Pro-X-X-X-Glu-Leu (RPEL) motifs. The NLS residues of MAL adopt an extended conformation and bind along the surface groove of importin-{alpha}, interacting with the major- and minor-NLS binding sites. We also present a crystal structure of wild-type MAL RPEL domain in complex with five G-actins. Comparison of the importin-{alpha}- and actin-complexes revealed that the binding of G-actins to MAL is associated with folding of NLS residues into a helical conformation that is inappropriate for importin-{alpha} recognition.

  16. Imaging performance of attenuated phase-shift mask using coherent scattering microscope

    NASA Astrophysics Data System (ADS)

    Lee, Jae Uk; Jeong, SeeJun; Hong, Seong Chul; Lee, Seung Min; Ahn, Jinho

    2014-03-01

    The half-tone phase shift mask (PSM) has been suggested for better imaging performances like image contrast, NILS and H-V bias compared to the binary mask (BIM) in EUV lithography. In this paper, we measured imaging performance of a fabricated half-tone attenuated PSM with Coherent Scattering Microscopy (CSM) and the results were compared with simulation data obtained by EM-suite tool. We prepared a half-tone attenuated PSM which has 12.7% reflectivity and 180° phase shift with absorber stack of 16.5mn-thick TaN absorber and 24nm-thick Mo phase shifter. With CSM, an actinic inspection tool, we measured the imaging properties of PSM. The diffraction efficiencies of BIM were measured as 31%, 36%, and 44% for 88 nm, 100 nm, and 128 nm mask CD, respectively, while those of PSM were measured as 45%, 62%, and 81%. Also the aerial image at wafer level obtained by CSM with high volume manufacturing tool's (HVM) illumination condition (NA=0.33, σ=0.9) showed higher image contrast and NILS with phase shift effect. And the measured data were consistent with the simulation data.

  17. Particle removal challenges with EUV patterned mask for the sub-22nm HP node

    SciTech Connect

    Rastegar, A.; Eichenlaub, S.; Kadaksham, A. J.; Lee, B.; House, M.; Huh, S.; Cha, B.; Yun, H.; Mochi, I.; Goldberg, K. A.

    2010-03-12

    The particle removal efficiency (PRE) of cleaning processes diminishes whenever the minimum defect size for a specific technology node becomes smaller. For the sub-22 nm half-pitch (HP) node, it was demonstrated that exposure to high power megasonic up to 200 W/cm{sup 2} did not damage 60 nm wide TaBN absorber lines corresponding to the 16 nm HP node on wafer. An ammonium hydroxide mixture and megasonics removes {ge}50 nm SiO{sub 2} particles with a very high PRE, A sulfuric acid hydrogen peroxide mixture (SPM) in addition to ammonium hydroxide mixture (APM) and megasonic is required to remove {ge}28 nm SiO{sub 2} particles with a high PRE. Time-of-flight secondary ion mass spectroscopy (TOFSIMS) studies show that the presence of O{sub 2} during a vacuum ultraviolet (VUV) ({lambda} = 172 nm) surface conditioning step will result in both surface oxidation and Ru removal, which drastically reduce extreme ultraviolet (EUV) mask life time under multiple cleanings. New EUV mask cleaning processes show negligible or no EUV reflectivity loss and no increase in surface roughness after up to 15 cleaning cycles. Reviewing of defect with a high current density scanning electron microscope (SEM) drastically reduces PRE and deforms SiO{sub 2} particles. 28 nm SiO{sub 2} particles on EUV masks age very fast and will deform over time, Care must be taken when reviewing EUV mask defects by SEM. Potentially new particles should be identified to calibrate short wavelength inspection tools, Based on actinic image review, 50 nm SiO{sub 2} particles on top of the EUV mask will be printed on the wafer.

  18. Masks: Interpretations and Variations.

    ERIC Educational Resources Information Center

    Basso, Robert

    1990-01-01

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

  19. Achievements and challenges of EUV mask imaging

    NASA Astrophysics Data System (ADS)

    Davydova, Natalia; van Setten, Eelco; de Kruif, Robert; Connolly, Brid; Fukugami, Norihito; Kodera, Yutaka; Morimoto, Hiroaki; Sakata, Yo; Kotani, Jun; Kondo, Shinpei; Imoto, Tomohiro; Rolff, Haiko; Ullrich, Albrecht; Lammers, Ad; Schiffelers, Guido; van Dijk, Joep

    2014-07-01

    The impact of various mask parameters on CDU combined in a total mask budget is presented, for 22 nm lines, for reticles used for NXE:3300 qualification. Apart from the standard mask CD measurements, actinic spectrometry of multilayer is used to qualify reflectance uniformity over the image field; advanced 3D metrology is applied for absorber profile characterization including absorber height and side wall angle. The predicted mask impact on CDU is verified using actual exposure data collected on multiple NXE:3300 scanners. Mask 3D effects are addressed, manifesting themselves in best focus shifts for different structures exposed with off-axis illumination. Experimental NXE:3300 results for 16 nm dense lines and 20 nm (semi-)isolated spaces are shown: best focus range reaches 24 nm. A mitigation strategy by absorber height optimization is proposed based on experimental results of a special mask with varying absorber heights. Further development of a black image border for EUV mask is considered. The image border is a pattern free area surrounding image field preventing exposure the image field neighborhood on wafer. Normal EUV absorber is not suitable for this purpose as it has 1-3% EUV reflectance. A current solution is etching of ML down to substrate reducing EUV reflectance to <0.05%. A next step in the development of the black border is the reduction of DUV Out-of-Band reflectance (<1.5%) in order to cope with DUV light present in EUV scanners. Promising results achieved in this direction are shown.

  20. Application of DBM tool for detection of EUV mask defect

    NASA Astrophysics Data System (ADS)

    Yoo, Gyun; Kim, Jungchan; Park, Chanha; Lee, Taehyeong; Ji, Sunkeun; Yang, Hyunjo; Yim, Donggyu; Park, Byeongjun; Maruyama, Kotaro; Yamamoto, Masahiro

    2013-04-01

    Extreme ultraviolet lithography (EUVL) is one of the most leading lithography technologies for high volume manufacturing. The EUVL is based on reflective optic system therefore critical patterning issues are arisen from the surface of photomask. Defects below and inside of the multilayer or absorber of EUV photomask is one of the most critical issues to implement EUV lithography in mass production. It is very important to pick out and repair printable mask defects. Unfortunately, however, infrastructure for securing the defect free photomask such as inspection tool is still under development furthermore it does not seem to be ready soon. In order to overcome the lack of infrastructures for EUV mask inspection, we will discuss an alternative methodology which is based on wafer inspection results using DBM (Design Based Metrology) tool. It is very challenging for metrology to quantify real mask defect from wafer inspection result since various sources are possible contributor. One of them is random defect comes from poor CD uniformity. It is probable that those random defects are majority of a defect list including real mask defects. It is obvious that CD uniformity should be considered to pick out only a real mask defect. In this paper, the methodology to determine real mask defect from the wafer inspection results will be discussed. Experiments are carried out on contact layer and on metal layer using mask defect inspection tool, Teron(KLA6xx) and DBM (Design Based Metrology) tool, NGR2170™.

  1. 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.

  2. Masks and Other Disguises.

    ERIC Educational Resources Information Center

    Ploghoft, Debra

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

  3. Actin in Herpesvirus Infection

    PubMed Central

    Roberts, Kari L.; Baines, Joel D.

    2011-01-01

    Actin is important for a variety of cellular processes, including uptake of extracellular material and intracellular transport. Several emerging lines of evidence indicate that herpesviruses exploit actin and actin-associated myosin motors for viral entry, intranuclear transport of capsids, and virion egress. The goal of this review is to explore these processes and to highlight potential future directions for this area of research. PMID:21994736

  4. Actin Rings of Power.

    PubMed

    Schwayer, Cornelia; Sikora, Mateusz; Slováková, Jana; Kardos, Roland; Heisenberg, Carl-Philipp

    2016-06-20

    Circular or ring-like actin structures play important roles in various developmental and physiological processes. Commonly, these rings are composed of actin filaments and myosin motors (actomyosin) that, upon activation, trigger ring constriction. Actomyosin ring constriction, in turn, has been implicated in key cellular processes ranging from cytokinesis to wound closure. Non-constricting actin ring-like structures also form at cell-cell contacts, where they exert a stabilizing function. Here, we review recent studies on the formation and function of actin ring-like structures in various morphogenetic processes, shedding light on how those different rings have been adapted to fulfill their specific roles. PMID:27326928

  5. Vinculin Is a Dually Regulated Actin Filament Barbed End-capping and Side-binding Protein

    PubMed Central

    Le Clainche, Christophe; Dwivedi, Satya Prakash; Didry, Dominique; Carlier, Marie-France

    2010-01-01

    The focal adhesion protein vinculin is an actin-binding protein involved in the mechanical coupling between the actin cytoskeleton and the extracellular matrix. An autoinhibitory interaction between the N-terminal head (Vh) and the C-terminal tail (Vt) of vinculin masks an actin filament side-binding domain in Vt. The binding of several proteins to Vh disrupts this intramolecular interaction and exposes the actin filament side-binding domain. Here, by combining kinetic assays and microscopy observations, we show that Vt inhibits actin polymerization by blocking the barbed ends of actin filaments. In low salt conditions, Vt nucleates actin filaments capped at their barbed ends. We determined that the interaction between vinculin and the barbed end is characterized by slow association and dissociation rate constants. This barbed end capping activity requires C-terminal amino acids of Vt that are dispensable for actin filament side binding. Like the side-binding domain, the capping domain of vinculin is masked by an autoinhibitory interaction between Vh and Vt. In contrast to the side-binding domain, the capping domain is not unmasked by the binding of a talin domain to Vh and requires the dissociation of an additional autoinhibitory interaction. Finally, we show that vinculin and the formin mDia1, which is involved in the processive elongation of actin filaments in focal adhesions, compete for actin filament barbed ends. PMID:20484056

  6. Determining the Critcial Size of EUV Mask Substrate Defects

    SciTech Connect

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

    2008-02-28

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

  7. Determining the critical size of EUV mask substrate defects

    SciTech Connect

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

    2008-05-26

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

  8. Masking the Color Wheel.

    ERIC Educational Resources Information Center

    Greene, Charlene

    1982-01-01

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

  9. EUV mask process specifics and development challenges

    NASA Astrophysics Data System (ADS)

    Nesladek, Pavel

    2014-07-01

    EUV lithography is currently the favorite and most promising candidate among the next generation lithography (NGL) technologies. Decade ago the NGL was supposed to be used for 45 nm technology node. Due to introduction of immersion 193nm lithography, double/triple patterning and further techniques, the 193 nm lithography capabilities was greatly improved, so it is expected to be used successfully depending on business decision of the end user down to 10 nm logic. Subsequent technology node will require EUV or DSA alternative technology. Manufacturing and especially process development for EUV technology requires significant number of unique processes, in several cases performed at dedicated tools. Currently several of these tools as e.g. EUV AIMS or actinic reflectometer are not available on site yet. The process development is done using external services /tools with impact on the single unit process development timeline and the uncertainty of the process performance estimation, therefore compromises in process development, caused by assumption about similarities between optical and EUV mask made in experiment planning and omitting of tests are further reasons for challenges to unit process development. Increased defect risk and uncertainty in process qualification are just two examples, which can impact mask quality / process development. The aim of this paper is to identify critical aspects of the EUV mask manufacturing with respect to defects on the mask with focus on mask cleaning and defect repair and discuss the impact of the EUV specific requirements on the experiments needed.

  10. Direct dynamin–actin interactions regulate the actin cytoskeleton

    PubMed Central

    Gu, Changkyu; Yaddanapudi, Suma; Weins, Astrid; Osborn, Teresia; Reiser, Jochen; Pollak, Martin; Hartwig, John; Sever, Sanja

    2010-01-01

    The large GTPase dynamin assembles into higher order structures that are thought to promote endocytosis. Dynamin also regulates the actin cytoskeleton through an unknown, GTPase-dependent mechanism. Here, we identify a highly conserved site in dynamin that binds directly to actin filaments and aligns them into bundles. Point mutations in the actin-binding domain cause aberrant membrane ruffling and defective actin stress fibre formation in cells. Short actin filaments promote dynamin assembly into higher order structures, which in turn efficiently release the actin-capping protein (CP) gelsolin from barbed actin ends in vitro, allowing for elongation of actin filaments. Together, our results support a model in which assembled dynamin, generated through interactions with short actin filaments, promotes actin polymerization via displacement of actin-CPs. PMID:20935625

  11. Replicated mask surface roughness effects on EUV lithographic pattering and line edge roughness

    SciTech Connect

    George, Simi A.; Naulleau, Patrick P.; Gullikson, Eric M.; Mochi, Iacopo; Salmassi, Farhad; Goldberg, Kenneth A.; Anderson, Erik H.

    2011-03-11

    To quantify the roughness contributions to speckle, a programmed roughness substrate was fabricated with a number of areas having different roughness magnitudes. The substrate was then multilayer coated. Atomic force microscopy (AFM) surface maps were collected before and after multilayer deposition. At-wavelength reflectance and total integrated scattering measurements were also completed. Angle resolved scattering based power spectral densities are directly compared to the AFM based power spectra. We show that AFM overpredicts the roughness in the picometer measurements range. The mask was then imaged at-wavelength for the direct characterization of the aerial image speckle using the SEMATECH Berkeley Actinic Inspection Tool (AIT). Modeling was used to test the effectiveness of the different metrologies in predicting the measured aerial-image speckle. AIT measured contrast values are 25% or more than the calculated image contrast values obtained using the measured rms roughness input. The extent to which the various metrologies can be utilized for specifying tolerable roughness limits on EUV masks is still to be determined. Further modeling and measurements are being planned.

  12. Attention Attenuates Metacontrast Masking

    ERIC Educational Resources Information Center

    Boyer, Jennifer; Ro, Tony

    2007-01-01

    The influence of attention on perceptual awareness was examined using metacontrast masking. Attention was manipulated with endogenous cues to assess the effects on the temporal and spatial parameters of target visibility. Experiment 1 examined the time course of effective masking when the target and mask set were presented at an attended vs. an…

  13. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

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

  14. Dynamin at actin tails.

    PubMed

    Lee, Eunkyung; De Camilli, Pietro

    2002-01-01

    Dynamin, the product of the shibire gene of Drosophila, is a GTPase critically required for endocytosis. Some studies have suggested a functional link between dynamin and the actin cytoskeleton. This link is of special interest, because there is evidence implicating actin dynamics in endocytosis. Here we show that endogenous dynamin 2, as well as green fluorescence protein fusion proteins of both dynamin 1 and 2, is present in actin comets generated by Listeria or by type I PIP kinase (PIPK) overexpression. In PIPK-induced tails, dynamin is further enriched at the interface between the tails and the moving organelles. Dynamin mutants harboring mutations in the GTPase domain inhibited nucleation of actin tails induced by PIPK and moderately reduced their speed. Although dynamin localization to the tails required its proline-rich domain, expression of a dynamin mutant lacking this domain also diminished tail formation. In addition, this mutant disrupted a membrane-associated actin scaffold (podosome rosette) previously shown to include dynamin. These findings suggest that dynamin is part of a protein network that controls nucleation of actin from membranes. At endocytic sites, dynamin may couple the fission reaction to the polymerization of an actin pool that functions in the separation of the endocytic vesicles from the plasma membrane. PMID:11782545

  15. Aerial imaging study of the mask-induced line-width roughness of EUV lithography masks

    NASA Astrophysics Data System (ADS)

    Wojdyla, Antoine; Donoghue, Alexander; Benk, Markus P.; Naulleau, Patrick P.; Goldberg, Kenneth A.

    2016-03-01

    EUV lithography uses reflective photomasks to print features on a wafer through the formation of an aerial image. The aerial image is influenced by the mask's substrate and pattern roughness and by photon shot noise, which collectively affect the line-width on wafer prints, with an impact on local critical dimension uniformity (LCDU). We have used SHARP, an actinic mask-imaging microscope, to study line-width roughness (LWR) in aerial images at sub-nanometer resolution. We studied the impact of photon density and the illumination partial coherence on recorded images, and found that at low coherence settings, the line-width roughness is dominated by photon noise, while at high coherence setting, the effect of speckle becomes more prominent, dominating photon noise for exposure levels of 4 photons/nm2 at threshold on the mask size.

  16. Actin Mechanics and Fragmentation*

    PubMed Central

    De La Cruz, Enrique M.; Gardel, Margaret L.

    2015-01-01

    Cell physiological processes require the regulation and coordination of both mechanical and dynamical properties of the actin cytoskeleton. Here we review recent advances in understanding the mechanical properties and stability of actin filaments and how these properties are manifested at larger (network) length scales. We discuss how forces can influence local biochemical interactions, resulting in the formation of mechanically sensitive dynamic steady states. Understanding the regulation of such force-activated chemistries and dynamic steady states reflects an important challenge for future work that will provide valuable insights as to how the actin cytoskeleton engenders mechanoresponsiveness of living cells. PMID:25957404

  17. 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).

  18. Actin Automata with Memory

    NASA Astrophysics Data System (ADS)

    Alonso-Sanz, Ramón; Adamatzky, Andy

    Actin is a globular protein which forms long polar filaments in eukaryotic. The actin filaments play the roles of cytoskeleton, motility units, information processing and learning. We model actin filament as a double chain of finite state machines, nodes, which take states “0” and “1”. The states are abstractions of absence and presence of a subthreshold charge on actin units corresponding to the nodes. All nodes update their state in parallel to discrete time. A node updates its current state depending on states of two closest neighbors in the node chain and two closest neighbors in the complementary chain. Previous models of actin automata consider momentary state transitions of nodes. We enrich the actin automata model by assuming that states of nodes depend not only on the current states of neighboring node but also on their past states. Thus, we assess the effect of memory of past states on the dynamics of acting automata. We demonstrate in computational experiments that memory slows down propagation of perturbations, decrease entropy of space-time patterns generated, transforms traveling localizations to stationary oscillators, and stationary oscillations to still patterns.

  19. Phase measurements of EUV mask defects

    DOE PAGES

    Claus, Rene A.; Wang, Yow-Gwo; Wojdyla, Antoine; Benk, Markus P.; Goldberg, Kenneth A.; Neureuther, Andrew R.; Naulleau, Patrick P.; Waller, Laura

    2015-02-22

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

  20. Phase measurements of EUV mask defects

    SciTech Connect

    Claus, Rene A.; Wang, Yow-Gwo; Wojdyla, Antoine; Benk, Markus P.; Goldberg, Kenneth A.; Neureuther, Andrew R.; Naulleau, Patrick P.; Waller, Laura

    2015-02-22

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

  1. The Molecular Evolution of Actin

    PubMed Central

    Hightower, Robin C.; Meagher, Richard B.

    1986-01-01

    We have investigated the molecular evolution of plant and nonplant actin genes comparing nucleotide and amino acid sequences of 20 actin genes. Nucleotide changes resulting in amino acid substitutions (replacement substitutions) ranged from 3–7% for all pairwise comparisons of animal actin genes with the following exceptions. Comparisons between higher animal muscle actin gene sequences and comparisons between higher animal cytoplasmic actin gene sequences indicated <3% divergence. Comparisons between plant and nonplant actin genes revealed, with two exceptions, 11–15% replacement substitution. In the analysis of plant actins, replacement substitution between soybean actin genes SAc1, SAc3, SAc4 and maize actin gene MAc1 ranged from 8–10%, whereas these members within the soybean actin gene family ranged from 6–9% replacement substitution. The rate of sequence divergence of plant actin sequences appears to be similar to that observed for animal actins. Furthermore, these and other data suggest that the plant actin gene family is ancient and that the families of soybean and maize actin genes have diverged from a single common ancestral plant actin gene that originated long before the divergence of monocots and dicots. The soybean actin multigene family encodes at least three classes of actin. These classes each contain a pair of actin genes that have been designated kappa (SAc1, SAc6), lambda (SAc2, SAc4) and mu (SAc3, SAc7). The three classes of soybean actin are more divergent in nucleotide sequence from one another than higher animal cytoplasmic actin is divergent from muscle actin. The location and distribution of amino acid changes were compared between actin proteins from all sources. A comparison of the hydropathy of all actin sequences, except from Oxytricha, indicated a strong similarity in hydropathic character between all plant and nonplant actins despite the greater number of replacement substitutions in plant actins. These protein sequence

  2. Removable pellicle for lithographic mask protection and handling

    DOEpatents

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

    2002-01-01

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

  3. 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.

  4. Inspection of 32nm imprinted patterns with an advanced e-beam inspection system

    NASA Astrophysics Data System (ADS)

    Xiao, Hong; Ma, Long; Wang, Fei; Zhao, Yan; Jau, Jack; Selinidis, Kosta; Thompson, Ecron; Sreenivasan, S. V.; Resnick, Douglas J.

    2009-10-01

    We used electron beam (e-beam) inspection (EBI) systems to inspect nano imprint lithography (NIL) resist wafers with programmed defects. EBI with 10nm pixel sizes has been demonstrated and capability of capturing program defects sized as small as 4nm has been proven. Repeating defects have been captured by the EBI in multiple die inspections to identify the possible mask defects. This study demonstrated the feasibility of EBI as the NIL defect inspection solution of 32nm and beyond.

  5. Binary mask programmable hologram.

    PubMed

    Tsang, P W M; Poon, T-C; Zhou, Changhe; Cheung, K W K

    2012-11-19

    We report, for the first time, the concept and generation of a novel Fresnel hologram called the digital binary mask programmable hologram (BMPH). A BMPH is comprised of a static, high resolution binary grating that is overlaid with a lower resolution binary mask. The reconstructed image of the BMPH can be programmed to approximate a target image (including both intensity and depth information) by configuring the pattern of the binary mask with a simple genetic algorithm (SGA). As the low resolution binary mask can be realized with less stringent display technology, our method enables the development of simple and economical holographic video display.

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

    ERIC Educational Resources Information Center

    Lim, Stephen Wee Hun; Chua, Fook K.

    2008-01-01

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

  7. Intranuclear Actin Regulates Osteogenesis

    PubMed Central

    Sen, Buer; Xie, Zhihui; Uzer, Gunes; Thompson, William R.; Styner, Maya; Wu, Xin; Rubin, Janet

    2016-01-01

    Depolymerization of the actin cytoskeleton induces nuclear trafficking of regulatory proteins and global effects on gene transcription. We here show that in mesenchymal stem cells (MSCs), cytochalasin D treatment causes rapid cofilin-/importin-9-dependent transfer of G-actin into the nucleus. The continued presence of intranuclear actin, which forms rod-like structures that stain with phalloidin, is associated with induction of robust expression of the osteogenic genes osterix and osteocalcin in a Runx2-dependent manner, and leads to acquisition of osteogenic phenotype. Adipogenic differentiation also occurs, but to a lesser degree. Intranuclear actin leads to nuclear export of Yes-associated protein (YAP); maintenance of nuclear YAP inhibits Runx2 initiation of osteogenesis. Injection of cytochalasin into the tibial marrow space of live mice results in abundant bone formation within the space of 1 week. In sum, increased intranuclear actin forces MSC into osteogenic lineage through controlling Runx2 activity; this process may be useful for clinical objectives of forming bone. PMID:26140478

  8. Defects caused by blank masks and repair solution with nanomachining for 20nm node

    NASA Astrophysics Data System (ADS)

    Lee, HyeMi; Kim, ByungJu; Kim, MunSik; Jung, HoYong; Kim, Sang Pyo; Yim, DongGyu

    2014-09-01

    As the number of masks per wafer product set is increasing and low k1 lithography requires tight mask specifications, the patterning process below sub 20nm tech. node for critical layers will be much more expensive compared with previous tech. generations. Besides, the improved resolution and the zero defect level are necessary to meet tighter specifications on a mask and these resulted in the increased the blank mask price as well as the mask fabrication cost. Unfortunately, in spite of expensive price of blank masks, the certain number of defects on the blank mask is transformed into the mask defects and its ratio is increased. But using high quality blank mask is not a good idea to avoid defects on the blank mask because the price of a blank mask is proportional to specifications related to defect level. Furthermore, particular defects generated from the specific process during manufacturing a blank mask are detected as a smaller defect than real size by blank inspection tools because of its physical properties. As a result, it is almost impossible to prevent defects caused by blank masks during the mask manufacturing. In this paper, blank defect types which is evolved into mask defects and its unique characteristics are observed. Also, the repair issues are reviewed such as the pattern damage according to the defect types and the repair solution is suggested to satisfy the AIMS (Arial Image Measurement System) specification using a nanomachining tool.

  9. Enhancement in Informational Masking

    ERIC Educational Resources Information Center

    Cao, Xiang; Richards, Virginia M.

    2012-01-01

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

  10. Lightweight Face Mask

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  11. Simulation of AIMS measurements using rigorous mask 3D modeling

    NASA Astrophysics Data System (ADS)

    Chou, Chih-Shiang; Huang, Hsu-Ting; Chu, Fu-Sheng; Chu, Yuan-Chih; Huang, Wen-Chun; Liu, Ru-Gun; Gau, Tsai-Sheng

    2015-03-01

    Aerial image measurement system (AIMSTM) has been widely used for wafer level inspection of mask defects. Reported inspection flows include die-to-die (D2D) and die-to-database (D2DB) methods. For patterns that do not repeat in another die, only the D2DB approach is applicable. The D2DB method requires accurate simulation of AIMS measurements for a mask pattern. An optical vectorial model is needed to depict the mask diffraction effect in this simulation. To accurately simulate the imaging results, a rigorous electro-magnetic field (EMF) model is essential to correctly take account of the EMF scattering induced by the mask topography, which is usually called the mask 3D effect. In this study, the mask 3D model we use is rigorous coupled-wave analysis (RCWA), which calculates the diffraction fields from a single plane wave incidence. A hybrid Hopkins-Abbe method with RCWA is used to calculate the EMF diffraction at a desired accuracy level while keeping the computation time practical. We will compare the speed of the hybrid Hopkins-Abbe method to the rigorous Abbe method. The matching between simulation and experiment is more challenging for AIMS than CD-SEM because its measurements provide full intensity information. Parameters in the mask 3D model such as film stack thickness or film optical properties, is optimized during the fitting process. We will report the fitting results of AIMS images for twodimensional structures with various pitches. By accurately simulating the AIMS measurements, it provides a necessary tool to perform the mask inspection using the D2DB approach and to accurately predict the mask defects.

  12. Exploring EUV mask backside defectivity and control methods

    NASA Astrophysics Data System (ADS)

    Turley, Christina; Rankin, Jed; Kindt, Louis; Lawliss, Mark; Bolton, Luke; Collins, Kevin; Cheong, Lin; Bonam, Ravi; Poro, Richard; Isogawa, Takeshi; Narita, Eisuke; Kagawa, Masayuki

    2015-07-01

    The backside of photomasks have been largely ignored during the last several decades of development, with the exception of avoiding gross damage or defects, as almost all problems are far enough out of the focal plane to have minimal effect on imaging. Since EUV masks are reflective, and the column is held in a vacuum, scanners have been designed to utilize electrostatic chucking. With the chucking system for EUV, the requirements for the backside of the mask must be redefined to integrate concerns in substrate design, mask manufacturing, and usage. The two key concerns with respect to an electrostatic chuck are defects and durability. Backside defects can affect imaging, while potentially damaging or contaminating the tool, the mask, or even subsequently used masks. Compromised durability, from either usage or cleaning, can affect the ability of the chuck to hold the mask in place. In this study, these concerns are evaluated in three stages: minimizing defects created during mask fabrication, actions taken upon discovery of defects, and durability of the backside film with continued cleans and chucking. Data incorporated in this study includes: sheet resistance, film thickness, and optical inspection images. Incorporating the data from the three stages of fabrication, disposition, and lifetime will help us define how to structure backside EUV mask handling during mask manufacture and indicate what further solutions are needed as EUV technology transitions into manufacturing.

  13. Extreme ultraviolet mask substrate surface roughness effects on lithography patterning

    SciTech Connect

    George, Simi; Naulleau, Patrick; Salmassi, Farhad; Mochi, Iacopo; Gullikson, Eric; Goldberg, Kenneth; Anderson, Erik

    2010-06-21

    In extreme ultraviolet lithography exposure systems, mask substrate roughness induced scatter contributes to LER at the image plane. In this paper, the impact of mask substrate roughness on image plane speckle is explicitly evaluated. A programmed roughness mask was used to study the correlation between mask roughness metrics and wafer plane aerial image inspection. We find that the roughness measurements by top surface topography profile do not provide complete information on the scatter related speckle that leads to LER at the image plane. We suggest at wavelength characterization by imaging and/or scatter measurements into different frequencies as an alternative for a more comprehensive metrology of the mask substrate/multilayer roughness effects.

  14. 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.

  15. 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.

  16. Amplification of actin polymerization forces

    PubMed Central

    Dmitrieff, Serge; Nédélec, François

    2016-01-01

    The actin cytoskeleton drives many essential processes in vivo, using molecular motors and actin assembly as force generators. We discuss here the propagation of forces caused by actin polymerization, highlighting simple configurations where the force developed by the network can exceed the sum of the polymerization forces from all filaments. PMID:27002174

  17. Introduction of new database reflected tritone algorithm for application in mask production

    NASA Astrophysics Data System (ADS)

    Schulmeyer, Thomas; Schmalfuss, Heiko; Heumann, Jan; Lang, Michael

    2008-04-01

    At Photomask Japan 2007 the new algorithm of Fast Integrated die-to-die T+R (DDTR) for the views of P90 and P72 for the KLA Tencor TeraScanHR mask inspection system was presented. At the same time a new algorithm for P72 in database tritone mode for reflected light (DBRt) was introduced. Both modes can be used together as one combined inspection to detect pattern and contamination defects on production masks. It was shown that these new algorithms allow for creation of a new inspection strategy with improved throughput and a reduced amount of inspections. Currently an inspection strategy has to cover at first a pattern inspection (normally a combination of die-to-die and additional database inspections) for finding hard defects on a mask and then as second step a contamination inspection (STARlight2 TM). The hard defects have to be repaired and the contaminations can be cleaned. The new inspection strategy allows for detection of all critical hard and contamination defects on a mask with one single combined inspection, enhancing productivity. At BACUS 2007 the first evaluation of this new kind of inspection strategy for manufacturing of masks was described for two production plates of different design. At that time only the database reflected tritone algorithm for the view of P72 was available. The changes in inspection strategy could only go together with a change of view from P90 to P72. With view P72 higher overall sensitivity could be reached and smaller secondary features could be inspected. However, these improvements may not be necessary for all plates and may need more time than a comparable P90 inspection. Today the standard contamination inspection for critical masks is the P90 STARlight2 TM (SL2). To do a time effective parallel combo inspection with DDTR and DBRt the same view has to be used. An extension of the database reflected tritone algorithm to the P90 view is now available. This gives the mask manufacturer the flexibility to change the

  18. Control of actin-based motility through localized actin binding.

    PubMed

    Banigan, Edward J; Lee, Kun-Chun; Liu, Andrea J

    2013-12-01

    A wide variety of cell biological and biomimetic systems use actin polymerization to drive motility. It has been suggested that an object such as a bacterium can propel itself by self-assembling a high concentration of actin behind it, if it is repelled by actin. However, it is also known that it is essential for the moving object to bind actin. Therefore, a key question is how the actin tail can propel an object when it both binds and repels the object. We present a physically consistent Brownian dynamics model for actin-based motility that includes the minimal components of the dendritic nucleation model and allows for both attractive and repulsive interactions between actin and a moveable disc. We find that the concentration gradient of filamentous actin generated by polymerization is sufficient to propel the object, even with moderately strong binding interactions. Additionally, actin binding can act as a biophysical cap, and may directly control motility through modulation of network growth. Overall, this mechanism is robust in that it can drive motility against a load up to a stall pressure that depends on the Young's modulus of the actin network and can explain several aspects of actin-based motility.

  19. Protective Face Mask

    NASA Technical Reports Server (NTRS)

    1981-01-01

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

  20. EUVL Mask Blank Repair

    SciTech Connect

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

    2002-05-22

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

  1. New critical dimension uniformity measurement concept based reticle inspection tool

    NASA Astrophysics Data System (ADS)

    Seo, Kangjoon; Kim, MunSik; Kim, Sang Chul; Shin, JaeCheon; Kim, ChangYeol; Miller, John; Dayal, Aditya; Hutchinson, Trent; Park, KiHun

    2010-05-01

    The Critical Dimension Uniformity (CDU) specification on photo-mask is getting increasingly tighter which each successive node. The ITRS roadmap for optical masks indicates that, the CDU (3 sigma) for dense lines for binary or attenuated phase shift mask is 3.4nm for 45nm half-pitch (45HP) node and will go down to 2.4nm for 32HP node. The current variability in mask shop processes results in CDU variation across the photo-mask of ~2-3nm. Hence, we are entering in a phase where the mask CDU specification is approaching the limit of the capability of the current POR (process on record). Hence, mask shops have started exploring more active mechanisms to improve or compensate for the CDU of the masks. A typical application is in feeding back the CDU data to adjust the mask writer dose and compensate for non-uniformity in the CDs, resulting in improved quality of subsequent masks. Another option is to feed the CD uniformity information forward into the wafer FAB and adjust the scanner dose to correct for reticle non-uniformity. For these purposes mask makers prefer a dense measurement of CDs across the reticle in a short time. Mask makers are currently using the CD-SEM tool for data collection. While the resolution of SEM data ensures its position as the industry standard, an output map of CDU from a reticle inspection tool has the advantage of denser sampling over larger areas on the mask. High NA reticle inspection systems scan the entire reticle at high throughput, and are ideally suited for collecting CDU data on a dense grid. In this paper, we describe the basic theory of a new, reticle inspection-based CDU tool, and results on advanced memory masks. We discuss possible applications of CDU maps for optimizing the mask manufacturing and wafer production processes.

  2. Guardians of the actin monomer.

    PubMed

    Xue, Bo; Robinson, Robert C

    2013-01-01

    Actin is a universal force provider in eukaryotic cells. Biological processes harness the pressure generated from actin polymerization through dictating the time, place and direction of filament growth. As such, polymerization is initiated and maintained via tightly controlled filament nucleation and elongation machineries. Biological systems integrate force into their activities through recruiting and activating these machineries. In order that actin function as a common force generating polymerization motor, cells must maintain a pool of active, polymerization-ready monomeric actin, and minimize extemporaneous polymerization. Maintenance of the active monomeric actin pool requires the recycling of actin filaments, through depolymerization, nucleotide exchange and reloading of the polymerization machineries, while the levels of monomers are constantly monitored and supplemented, when needed, via the access of a reserve pool of monomers and through gene expression. Throughout its monomeric life, actin needs to be protected against gratuitous nucleation events. Here, we review the proteins that act as custodians of monomeric actin. We estimate their levels on a tissue scale, and calculate the implied concentrations of each actin complex based on reported binding affinities. These estimations predict that monomeric actin is rarely, if ever, alone. Thus, the guardians keep the volatility of actin in check, so that its explosive power is only released in the controlled environments of the nucleation and polymerization machineries. PMID:24268205

  3. 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.

  4. 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.

  5. New mask technology challenges

    NASA Astrophysics Data System (ADS)

    Kimmel, Kurt R.

    2001-09-01

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

  6. Actin stress in cell reprogramming

    PubMed Central

    Guo, Jun; Wang, Yuexiu; Sachs, Frederick; Meng, Fanjie

    2014-01-01

    Cell mechanics plays a role in stem cell reprogramming and differentiation. To understand this process better, we created a genetically encoded optical probe, named actin–cpstFRET–actin (AcpA), to report forces in actin in living cells in real time. We showed that stemness was associated with increased force in actin. We reprogrammed HEK-293 cells into stem-like cells using no transcription factors but simply by softening the substrate. However, Madin-Darby canine kidney (MDCK) cell reprogramming required, in addition to a soft substrate, Harvey rat sarcoma viral oncogene homolog expression. Replating the stem-like cells on glass led to redifferentiation and reduced force in actin. The actin force probe was a FRET sensor, called cpstFRET (circularly permuted stretch sensitive FRET), flanked by g-actin subunits. The labeled actin expressed efficiently in HEK, MDCK, 3T3, and bovine aortic endothelial cells and in multiple stable cell lines created from those cells. The viability of the cell lines demonstrated that labeled actin did not significantly affect cell physiology. The labeled actin distribution was similar to that observed with GFP-tagged actin. We also examined the stress in the actin cross-linker actinin. Actinin force was not always correlated with actin force, emphasizing the need for addressing protein specificity when discussing forces. Because actin is a primary structural protein in animal cells, understanding its force distribution is central to understanding animal cell physiology and the many linked reactions such as stress-induced gene expression. This new probe permits measuring actin forces in a wide range of experiments on preparations ranging from isolated proteins to transgenic animals. PMID:25422450

  7. Masks: The Artist in Me

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2009-01-01

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

  8. Defect printability analysis by lithographic simulation from high resolution mask images

    NASA Astrophysics Data System (ADS)

    Chen, George; Wiley, James N.; Wang, Jen-Shiang; Howell, Rafael C.; Bai, Shufeng; Chen, Yi-Fan; Chen, Frank; Cao, Yu; Takigawa, Tadahiro; Saito, Yasuko; Kurosawa, Terunobu; Tsuchiya, Hideo; Usuda, Kinya; Tokita, Masakazu; Ozaki, Fumio; Kikuiri, Nobutaka; Tsuji, Yoshitake

    2009-10-01

    We report the development of Mask-LMC for defect printability evaluation from sub-200nm wavelength mask inspection images. Both transmitted and reflected images are utilized, and both die-to-die and die-to-database inspection modes are supported. The first step of the process is to recover the patterns on the mask from high resolution T and R images by de-convolving inspection optical effects. This step uses a mask reconstruction model, which is based on rigorous Hopkins-modeling of the inspection optics, and is pre-determined before the full mask inspection. After mask reconstruction, wafer scanner optics and wafer resist simulations are performed on the reconstructed mask, with a wafer lithography model. This step leverages Brion's industry-proven, hardware-accelerated LMC (Lithography Manufacturability Check) technology1. Existing litho process models that are in use for Brion's OPC+ and verification products may be used for this simulation. In the final step, special detectors are used to compare simulation results on the reference and defect dice. We have developed detectors for contact CD, contact area, line and space CD, and edge placement errors. The detection results on test and production reticles have been validated with AIMSTM.

  9. Actin dynamics in living mammalian cells.

    PubMed

    Ballestrem, C; Wehrle-Haller, B; Imhof, B A

    1998-06-01

    The actin cytoskeleton maintains the cellular architecture and mediates cell movements. To explore actin cytoskeletal dynamics, the enhanced green fluorescent protein (EGFP) was fused to human &bgr ;-actin. The fusion protein was incorporated into actin fibers which became depolymerized upon cytochalasin B treatment. This functional EGFP-actin construct enabled observation of the actin cytoskeleton in living cells by time lapse fluorescence microscopy. Stable expression of the construct was obtained in mammalian cell lines of different tissue origins. In stationary cells, actin rich, ring-like structured 'actin clouds' were observed in addition to stress fibers. These ruffle-like structures were found to be involved in the reorganization of the actin cytoskeleton. In migratory cells, EGFP-actin was found in the advancing lamellipodium. Immobile actin spots developed in the lamellipodium and thin actin fibers formed parallel to the leading edge. Thus EGFP-actin expressed in living cells unveiled structures involved in the dynamics of the actin cytoskeleton.

  10. 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

  11. 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.

  12. 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.

  13. Critical dimension uniformity using reticle inspection tool

    NASA Astrophysics Data System (ADS)

    Wylie, Mark; Hutchinson, Trent; Pan, Gang; Vavul, Thomas; Miller, John; Dayal, Aditya; Hess, Carl; Green, Mike; Hedges, Shad; Chalom, Dan; Rudzinski, Maciej; Wood, Craig; McMurran, Jeff

    2009-10-01

    The Critical Dimension Uniformity (CDU) specification on photomasks continues to decrease with each successive node. The ITRS roadmap for optical masks indicates that the CDU (3 sigma) for dense lines on binary or attenuated phase shift mask is 3.4nm for the 45nm half-pitch (45HP) node and will decrease to 2.4nm for the 32HP node. The current capability of leading-edge mask shop patterning processes results in CDU variation across the photomask of a similar magnitude. Hence, we are entering a phase where the mask CDU specification is approaching the limit of the capability of the current Process of Record (POR). Mask shops have started exploring more active mechanisms to improve the CDU capability of the mask process. A typical application is feeding back the CDU data to adjust the mask writer dose to compensate for non-uniformity in the CDs, resulting in improved quality of subsequent masks. Mask makers are currently using the CD-SEM tool for this application. While the resolution of SEM data ensures its position as the industry standard and continued requirement to establish the photomask CD Mean to Target value, a dense measurement of CDs across the reticle with minimal cycle time impact would have value. In this paper, we describe the basic theory and application of a new, reticle inspection intensity-based CDU approach that has the advantage of dense sampling over larger areas on the mask. The TeraScanHR high NA reticle inspection system is used in this study; it can scan the entire reticle at relatively high throughput, and is ideally suited for collecting dense CDU data. We describe results obtained on advanced memory masks and discuss applications of CDU maps for optimizing the mask manufacturing process. A reticle inspection map of CDU is complementary to CD-SEM data. The dense data set has value for various applications, including feedback to mask writer and engineering analysis within the mask shop.

  14. Masked mycotoxins: A review

    PubMed Central

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

    2013-01-01

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

  15. Masked mycotoxins: a review.

    PubMed

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

    2013-01-01

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

  16. COAs: Behind the Masks.

    ERIC Educational Resources Information Center

    Birke, Szifra

    1993-01-01

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

  17. CADAT integrated circuit mask analysis

    NASA Technical Reports Server (NTRS)

    1981-01-01

    CADAT System Mask Analysis Program (MAPS2) is automated software tool for analyzing integrated-circuit mask design. Included in MAPS2 functions are artwork verification, device identification, nodal analysis, capacitance calculation, and logic equation generation.

  18. Pseudo-acetylation of K326 and K328 of actin disrupts Drosophila melanogaster indirect flight muscle structure and performance.

    PubMed

    Viswanathan, Meera C; Blice-Baum, Anna C; Schmidt, William; Foster, D Brian; Cammarato, Anthony

    2015-01-01

    In striated muscle tropomyosin (Tm) extends along the length of F-actin-containing thin filaments. Its location governs access of myosin binding sites on actin and, hence, force production. Intermolecular electrostatic associations are believed to mediate critical interactions between the proteins. For example, actin residues K326, K328, and R147 were predicted to establish contacts with E181 of Tm. Moreover, K328 also potentially forms direct interactions with E286 of myosin when the motor is strongly bound. Recently, LC-MS/MS analysis of the cardiac acetyl-lysine proteome revealed K326 and K328 of actin were acetylated, a post-translational modification (PTM) that masks the residues' inherent positive charges. Here, we tested the hypothesis that by removing the vital actin charges at residues 326 and 328, the PTM would perturb Tm positioning and/or strong myosin binding as manifested by altered skeletal muscle function and structure in the Drosophila melanogaster model system. Transgenic flies were created that permit tissue-specific expression of K326Q, K328Q, or K326Q/K328Q acetyl-mimetic actin and of wild-type actin via the UAS-GAL4 bipartite expression system. Compared to wild-type actin, muscle-restricted expression of mutant actin had a dose-dependent effect on flight ability. Moreover, excessive K328Q and K326Q/K328Q actin overexpression induced indirect flight muscle degeneration, a phenotype consistent with hypercontraction observed in other Drosophila myofibrillar mutants. Based on F-actin-Tm and F-actin-Tm-myosin models and on our physiological data, we conclude that acetylating K326 and K328 of actin alters electrostatic associations with Tm and/or myosin and thereby augments contractile properties. Our findings highlight the utility of Drosophila as a model that permits efficient targeted design and assessment of molecular and tissue-specific responses to muscle protein modifications, in vivo. PMID:25972811

  19. Pseudo-acetylation of K326 and K328 of actin disrupts Drosophila melanogaster indirect flight muscle structure and performance

    PubMed Central

    Viswanathan, Meera C.; Blice-Baum, Anna C.; Schmidt, William; Foster, D. Brian; Cammarato, Anthony

    2015-01-01

    In striated muscle tropomyosin (Tm) extends along the length of F-actin-containing thin filaments. Its location governs access of myosin binding sites on actin and, hence, force production. Intermolecular electrostatic associations are believed to mediate critical interactions between the proteins. For example, actin residues K326, K328, and R147 were predicted to establish contacts with E181 of Tm. Moreover, K328 also potentially forms direct interactions with E286 of myosin when the motor is strongly bound. Recently, LC-MS/MS analysis of the cardiac acetyl-lysine proteome revealed K326 and K328 of actin were acetylated, a post-translational modification (PTM) that masks the residues' inherent positive charges. Here, we tested the hypothesis that by removing the vital actin charges at residues 326 and 328, the PTM would perturb Tm positioning and/or strong myosin binding as manifested by altered skeletal muscle function and structure in the Drosophila melanogaster model system. Transgenic flies were created that permit tissue-specific expression of K326Q, K328Q, or K326Q/K328Q acetyl-mimetic actin and of wild-type actin via the UAS-GAL4 bipartite expression system. Compared to wild-type actin, muscle-restricted expression of mutant actin had a dose-dependent effect on flight ability. Moreover, excessive K328Q and K326Q/K328Q actin overexpression induced indirect flight muscle degeneration, a phenotype consistent with hypercontraction observed in other Drosophila myofibrillar mutants. Based on F-actin-Tm and F-actin-Tm-myosin models and on our physiological data, we conclude that acetylating K326 and K328 of actin alters electrostatic associations with Tm and/or myosin and thereby augments contractile properties. Our findings highlight the utility of Drosophila as a model that permits efficient targeted design and assessment of molecular and tissue-specific responses to muscle protein modifications, in vivo. PMID:25972811

  20. 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.

  1. 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.

  2. Mask strategy at International SEMATECH

    NASA Astrophysics Data System (ADS)

    Kimmel, Kurt R.

    2002-08-01

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

  3. Defect inspection of imprinted 32 nm half pitch patterns

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; McMackin, Ian; Perez, Joseph; Sreenivasan, S. V.; Resnick, Douglas J.

    2008-10-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  4. Electron beam inspection methods for imprint lithography at 32 nm

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Sreenivasan, S. V.; Resnick, Douglas J.

    2009-01-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  5. The Attentional Dynamics of Masked Detection

    ERIC Educational Resources Information Center

    Smith, Philip L.; Wolfgang, Bradley J.

    2004-01-01

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

  6. Formin' actin in the nucleus.

    PubMed

    Baarlink, Christian; Grosse, Robert

    2014-01-01

    Many if not most proteins can, under certain conditions, change cellular compartments, such as, for example, shuttling from the cytoplasm to the nucleus. Thus, many proteins may exert functions in various and very different subcellular locations, depending on the signaling context. A large amount of actin regulatory proteins has been detected in the mammalian cell nucleus, although their potential roles are much debated and are just beginning to emerge. Recently, members of the formin family of actin nucleators were also reported to dynamically localize to the nuclear environment. Here we discuss our findings that specific diaphanous-related formins can promote nuclear actin assembly in a signal-dependent manner.

  7. 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

  8. Revisiting mask contact hole measurements

    NASA Astrophysics Data System (ADS)

    Higuchi, Masaru; Gallagher, Emily; Ceperley, Daniel; Brunner, Timothy; Bowley, Reg; McGuire, Anne

    2006-10-01

    Contact holes represent one of the biggest critical dimension (CD) mask metrology challenges for 45nm technology mask development. The challenge is a consequence of both wafer and mask sensitivities. Large mask error factors and the small process windows found when contact holes are imaged on wafers impose very tight mask specifications for CD uniformity. The resultant CD error budget leaves little room for mask metrology. Current advanced mask metrology deploys a CD-SEM to characterize the mask contact hole CD uniformity. Measuring a contact hole is complex since it is inherently two-dimensional and is not always well-characterized by one-dimensional x- and y-axis measurements. This paper will investigate contact metrics such as line edge roughness (LER), region of interest (ROI) size, area, and CD sampling methods. The relative merits of each will be explored. Ultimately, an understanding of the connection between what is physically measured on the mask and what impacts wafer imaging must be understood. Simulations will be presented to explore the printability of a contact hole's physical attributes. The results will be summarized into a discussion of optimal contact hole metrology for 45nm technology node masks.

  9. Regulation of an Actin Spring

    NASA Astrophysics Data System (ADS)

    Tam, Barney; Shin, Jennifer; Brau, Ricardo; Lang, Matthew; Mahadevan, L.; Matsudaira, Paul

    2006-03-01

    To produce motion, cells rely on the conversion of potential energy into mechanical work. One such example is the dramatic process involving the acrosome reaction of Limulus sperm, whereby a 60 μm-long bundle of actin filaments straightens from a coiled conformation to extend out of the cell in five seconds. This cellular engine and the motion it produces represent a third type of actin-based motility fundamentally different from polymerization or myosin-driven processes. The motive force for this extension originates from stored elastic energy in the overtwisted, pre-formed coil---much like a compressed mechanical spring. When the actin bundle untwists, this energy is converted to mechanical work powering the extension. We report on experiments probing the regulation of this actin spring by extracellular calcium. We find that extracellular calcium needs to be present for the spring to activate, and that calcium regulates the velocity of the extension.

  10. Chemotaxis and Actin Oscillations

    NASA Astrophysics Data System (ADS)

    Bodenschatz, Eberhard; Hsu, Hsin-Fang; Negrete, Jose; Beta, Carsten; Pumir, Alain; Gholami, Azam; Tarantola, Marco; Westendorf, Christian; Zykov, Vladimir

    Recently, self-oscillations of the cytoskeletal actin have been observed in Dictyostelium, a model system for studying chemotaxis. Here we report experimental results on the self-oscillation mechanism and the role of regulatory proteins and myosin II. We stimulate cells rapidly and periodically by using photo un-caging of the chemoattractant in a micro-fluidic device and measured the cellular responses. We found that the response amplitude grows with stimulation strength only in a very narrow region of stimulation, after which the response amplitude reaches a plateau. Moreover, the frequency-response is not constant but rather varies with the strength of external stimuli. To understand the underlying mechanism, we analyzed the polymerization and de-polymerization time in the single cell level. Despite of the large cell-to-cell variability, we found that the polymerization time is independent of external stimuli and the de-polymerization time is prolonged as the stimulation strength increases. Our conclusions will be summarized and the role of noise in the signaling network will be discussed. German Science Foundation CRC 937.

  11. Three's company: the fission yeast actin cytoskeleton.

    PubMed

    Kovar, David R; Sirotkin, Vladimir; Lord, Matthew

    2011-03-01

    How the actin cytoskeleton assembles into different structures to drive diverse cellular processes is a fundamental cell biological question. In addition to orchestrating the appropriate combination of regulators and actin-binding proteins, different actin-based structures must insulate themselves from one another to maintain specificity within a crowded cytoplasm. Actin specification is particularly challenging in complex eukaryotes where a multitude of protein isoforms and actin structures operate within the same cell. Fission yeast Schizosaccharomyces pombe possesses a single actin isoform that functions in three distinct structures throughout the cell cycle. In this review we explore recent studies in fission yeast that help unravel how different actin structures operate in cells.

  12. Structural insights into de novo actin polymerization

    PubMed Central

    Dominguez, Roberto

    2010-01-01

    Summary Many cellular functions depend on rapid and localized actin polymerization/depolymerization. Yet, the de novo polymerization of actin in cells is kinetically unfavorable because of the instability of polymerization intermediates (small actin oligomers) and the actions of actin monomer binding proteins. Cells use filament nucleation and elongation factors to initiate and sustain polymerization. Structural biology is beginning to shed light on the diverse mechanisms by which these unrelated proteins initiate polymerization, undergo regulation, and mediate the transition of monomeric actin onto actin filaments. A prominent role is played by the W domain, which in some of these proteins occurs in tandem repeats that recruit multiple actin subunits. Pro-rich regions are also abundant and mediate the binding of profilin-actin complexes, which are the main source of polymerization competent actin in cells. Filament nucleation and elongation factors frequently interact with Rho family GTPases, which relay signals from membrane receptors to regulate actin cytoskeleton remodeling. PMID:20096561

  13. Mask fabrication process

    DOEpatents

    Cardinale, Gregory F.

    2000-01-01

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

  14. Polymerization of Actin from Maize Pollen.

    PubMed Central

    Yen, L. F.; Liu, X.; Cai, S.

    1995-01-01

    Here we describe the in vitro polymerization of actin from maize (Zea mays) pollen. The purified actin from maize pollen reported in our previous paper (X. Liu, L.F. Yen [1992] Plant Physiol 99: 1151-1155) is biologically active. In the presence of ATP, KCl, and MgCl2 the purified pollen actin polymerized into filaments. During polymerization the spectra of absorbance at 232 nm increased gradually. Polymerization of pollen actin was evidently accompanied by an increase in viscosity of the pollen actin solution. Also, the specific viscosity of pollen F-actin increased in a concentration-dependent manner. The ultraviolet difference spectrum of pollen actin is very similar to that of rabbit muscle actin. The activity of myosin ATPase from rabbit muscle was activated 7-fold by the polymerized pollen actin (F-actin). The actin filaments were visualized under the electron microscope as doubly wound strands of 7 nm diameter. If cytochalasin B was added before staining, no actin filaments were observed. When actin filaments were treated with rabbit heavy meromyosin, the actin filaments were decorated with an arrowhead structure. These results imply that there is much similarity between pollen and muscle actin. PMID:12228343

  15. Gβ Regulates Coupling between Actin Oscillators for Cell Polarity and Directional Migration.

    PubMed

    Hoeller, Oliver; Toettcher, Jared E; Cai, Huaqing; Sun, Yaohui; Huang, Chuan-Hsiang; Freyre, Mariel; Zhao, Min; Devreotes, Peter N; Weiner, Orion D

    2016-02-01

    For directional movement, eukaryotic cells depend on the proper organization of their actin cytoskeleton. This engine of motility is made up of highly dynamic nonequilibrium actin structures such as flashes, oscillations, and traveling waves. In Dictyostelium, oscillatory actin foci interact with signals such as Ras and phosphatidylinositol 3,4,5-trisphosphate (PIP3) to form protrusions. However, how signaling cues tame actin dynamics to produce a pseudopod and guide cellular motility is a critical open question in eukaryotic chemotaxis. Here, we demonstrate that the strength of coupling between individual actin oscillators controls cell polarization and directional movement. We implement an inducible sequestration system to inactivate the heterotrimeric G protein subunit Gβ and find that this acute perturbation triggers persistent, high-amplitude cortical oscillations of F-actin. Actin oscillators that are normally weakly coupled to one another in wild-type cells become strongly synchronized following acute inactivation of Gβ. This global coupling impairs sensing of internal cues during spontaneous polarization and sensing of external cues during directional motility. A simple mathematical model of coupled actin oscillators reveals the importance of appropriate coupling strength for chemotaxis: moderate coupling can increase sensitivity to noisy inputs. Taken together, our data suggest that Gβ regulates the strength of coupling between actin oscillators for efficient polarity and directional migration. As these observations are only possible following acute inhibition of Gβ and are masked by slow compensation in genetic knockouts, our work also shows that acute loss-of-function approaches can complement and extend the reach of classical genetics in Dictyostelium and likely other systems as well. PMID:26890004

  16. Gβ Regulates Coupling between Actin Oscillators for Cell Polarity and Directional Migration

    PubMed Central

    Cai, Huaqing; Sun, Yaohui; Huang, Chuan-Hsiang; Freyre, Mariel; Zhao, Min; Devreotes, Peter N.; Weiner, Orion D.

    2016-01-01

    For directional movement, eukaryotic cells depend on the proper organization of their actin cytoskeleton. This engine of motility is made up of highly dynamic nonequilibrium actin structures such as flashes, oscillations, and traveling waves. In Dictyostelium, oscillatory actin foci interact with signals such as Ras and phosphatidylinositol 3,4,5-trisphosphate (PIP3) to form protrusions. However, how signaling cues tame actin dynamics to produce a pseudopod and guide cellular motility is a critical open question in eukaryotic chemotaxis. Here, we demonstrate that the strength of coupling between individual actin oscillators controls cell polarization and directional movement. We implement an inducible sequestration system to inactivate the heterotrimeric G protein subunit Gβ and find that this acute perturbation triggers persistent, high-amplitude cortical oscillations of F-actin. Actin oscillators that are normally weakly coupled to one another in wild-type cells become strongly synchronized following acute inactivation of Gβ. This global coupling impairs sensing of internal cues during spontaneous polarization and sensing of external cues during directional motility. A simple mathematical model of coupled actin oscillators reveals the importance of appropriate coupling strength for chemotaxis: moderate coupling can increase sensitivity to noisy inputs. Taken together, our data suggest that Gβ regulates the strength of coupling between actin oscillators for efficient polarity and directional migration. As these observations are only possible following acute inhibition of Gβ and are masked by slow compensation in genetic knockouts, our work also shows that acute loss-of-function approaches can complement and extend the reach of classical genetics in Dictyostelium and likely other systems as well. PMID:26890004

  17. Cofilin-mediated actin dynamics promotes actin bundle formation during Drosophila bristle development

    PubMed Central

    Wu, Jing; Wang, Heng; Guo, Xuan; Chen, Jiong

    2016-01-01

    The actin bundle is an array of linear actin filaments cross-linked by actin-bundling proteins, but its assembly and dynamics are not as well understood as those of the branched actin network. Here we used the Drosophila bristle as a model system to study actin bundle formation. We found that cofilin, a major actin disassembly factor of the branched actin network, promotes the formation and positioning of actin bundles in the developing bristles. Loss of function of cofilin or AIP1, a cofactor of cofilin, each resulted in increased F-actin levels and severe defects in actin bundle organization, with the defects from cofilin deficiency being more severe. Further analyses revealed that cofilin likely regulates actin bundle formation and positioning by the following means. First, cofilin promotes a large G-actin pool both locally and globally, likely ensuring rapid actin polymerization for bundle initiation and growth. Second, cofilin limits the size of a nonbundled actin-myosin network to regulate the positioning of actin bundles. Third, cofilin prevents incorrect assembly of branched and myosin-associated actin filament into bundles. Together these results demonstrate that the interaction between the dynamic dendritic actin network and the assembling actin bundles is critical for actin bundle formation and needs to be closely regulated. PMID:27385345

  18. Cofilin-mediated actin dynamics promotes actin bundle formation during Drosophila bristle development.

    PubMed

    Wu, Jing; Wang, Heng; Guo, Xuan; Chen, Jiong

    2016-08-15

    The actin bundle is an array of linear actin filaments cross-linked by actin-bundling proteins, but its assembly and dynamics are not as well understood as those of the branched actin network. Here we used the Drosophila bristle as a model system to study actin bundle formation. We found that cofilin, a major actin disassembly factor of the branched actin network, promotes the formation and positioning of actin bundles in the developing bristles. Loss of function of cofilin or AIP1, a cofactor of cofilin, each resulted in increased F-actin levels and severe defects in actin bundle organization, with the defects from cofilin deficiency being more severe. Further analyses revealed that cofilin likely regulates actin bundle formation and positioning by the following means. First, cofilin promotes a large G-actin pool both locally and globally, likely ensuring rapid actin polymerization for bundle initiation and growth. Second, cofilin limits the size of a nonbundled actin-myosin network to regulate the positioning of actin bundles. Third, cofilin prevents incorrect assembly of branched and myosin-associated actin filament into bundles. Together these results demonstrate that the interaction between the dynamic dendritic actin network and the assembling actin bundles is critical for actin bundle formation and needs to be closely regulated.

  19. A Masked Photocathode in Photoinjector

    SciTech Connect

    Qiang, Ji

    2010-12-14

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

  20. Towards reduced impact of EUV mask defectivity on wafer

    NASA Astrophysics Data System (ADS)

    Jonckheere, R.; Van den Heuvel, D.; Pacco, A.; Pollentier, I.; Baudemprez, B.; Jehoul, C.; Hermans, J.; Hendrickx, E.

    2014-07-01

    The defectivity challenges of extreme ultraviolet (EUV) masks, that need to be addressed before production readiness of EUV lithography is assured from the mask perspective, are twofold. First, the EUV-specific defect type relating to the multi-layer (ML) mirror, the so-called ML-defects, require to become more detectable than they are printable. This not only requires proven capability of blank inspection, but also the existence of satisfactory printability mitigation strategies (comprising avoidance, pattern shift methodology, compensation repair). Both these assets need to become available within the mask supply chain, as there is little that can still be done about such residual defects at the wafer fab. In a production phase, finding unexpected printing ML-defects is unacceptable. It is shown how the specific way-of-working in use at imec, starting from the printed wafer, contributes to related learning and identification of remaining gaps, in getting this issue fully dealt with. The second challenge relates to particle contamination during use of the reticle at the wafer fab. Avoiding overlaycritical particles on the backside of NXE3100 reticles is facilitated by the established way-of-working. Minimizing the occurrence of particles "hopping" between reticles via the electrostatic clamp of the scanner (so-called clamp-traveling particles) is a major driver for appropriate mask cleaning. The latter may not have negative impact by frequent use, in view of the highly vulnerable EUV mask stack, and especially for the present "black-border" solution in which the ML is etched away at the image border on the reticle. A lot of effort is spent into monitoring of NXE3100 reticles for particle adders on the pattern side. This is realized by comparing past and present mask defect maps obtained by inspection of printed wafers with subsequent repeater analysis.

  1. What Is Being Masked in Object Substitution Masking?

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  2. Masked Proportional Routing

    NASA Technical Reports Server (NTRS)

    Wolpert, David

    2004-01-01

    Masked proportional routing is an improved procedure for choosing links between adjacent nodes of a network for the purpose of transporting an entity from a source node ("A") to a destination node ("B"). The entity could be, for example, a physical object to be shipped, in which case the nodes would represent waypoints and the links would represent roads or other paths between waypoints. For another example, the entity could be a message or packet of data to be transmitted from A to B, in which case the nodes could be computer-controlled switching stations and the links could be communication channels between the stations. In yet another example, an entity could represent a workpiece while links and nodes could represent, respectively, manufacturing processes and stages in the progress of the workpiece towards a finished product. More generally, the nodes could represent states of an entity and the links could represent allowed transitions of the entity. The purpose of masked proportional routing and of related prior routing procedures is to schedule transitions of entities from their initial states ("A") to their final states ("B") in such a manner as to minimize a cost or to attain some other measure of optimality or efficiency. Masked proportional routing follows a distributed (in the sense of decentralized) approach to probabilistically or deterministically choosing the links. It was developed to satisfy a need for a routing procedure that 1. Does not always choose the same link(s), even for two instances characterized by identical estimated values of associated cost functions; 2. Enables a graceful transition from one set of links to another set of links as the circumstances of operation of the network change over time; 3. Is preferably amenable to separate optimization of different portions of the network; 4. Is preferably usable in a network in which some of the routing decisions are made by one or more other procedure(s); 5. Preferably does not cause an

  3. Boolean gates on actin filaments

    NASA Astrophysics Data System (ADS)

    Siccardi, Stefano; Tuszynski, Jack A.; Adamatzky, Andrew

    2016-01-01

    Actin is a globular protein which forms long polar filaments in the eukaryotic cytoskeleton. Actin networks play a key role in cell mechanics and cell motility. They have also been implicated in information transmission and processing, memory and learning in neuronal cells. The actin filaments have been shown to support propagation of voltage pulses. Here we apply a coupled nonlinear transmission line model of actin filaments to study interactions between voltage pulses. To represent digital information we assign a logical TRUTH value to the presence of a voltage pulse in a given location of the actin filament, and FALSE to the pulse's absence, so that information flows along the filament with pulse transmission. When two pulses, representing Boolean values of input variables, interact, then they can facilitate or inhibit further propagation of each other. We explore this phenomenon to construct Boolean logical gates and a one-bit half-adder with interacting voltage pulses. We discuss implications of these findings on cellular process and technological applications.

  4. Masked Repetition Priming Using Magnetoencephalography

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  5. Combining Simultaneous with Temporal Masking

    ERIC Educational Resources Information Center

    Hermens, Frouke; Herzog, Michael H.; Francis, Gregory

    2009-01-01

    Simultaneous and temporal masking are two frequently used techniques in psychology and vision science. Although there are many studies and theories related to each masking technique, there are no systematic investigations of their mutual relationship, even though both techniques are often applied together. Here, the authors show that temporal…

  6. Mask registration and wafer overlay

    NASA Astrophysics Data System (ADS)

    Lee, Chulseung; Bang, Changjin; Kim, Myoungsoo; Kang, Hyosang; Lee, Dohwa; Jeong, Woonjae; Lim, Ok-Sung; Yoon, Seunghoon; Jung, Jaekang; Laske, Frank; Parisoli, Lidia; Roeth, Klaus-Dieter; Robinson, John C.; Jug, Sven; Izikson, Pavel; Dinu, Berta; Widmann, Amir; Choi, DongSub

    2010-03-01

    Overlay continues to be one of the key challenges for lithography in advanced semiconductor manufacturing. It becomes even more challenging due to the continued shrinking of the device node. Some low k1 techniques, such as Double Exposure and Double Patterning also add additional loss of the overlay margin due to the fact that the single layer pattern is created based on more than 1 exposure. Therefore, the overlay between 2 exposures requires very tight overlay specification. Mask registration is one of the major contributors to wafer overlay, especially field related overlay. We investigated mask registration and wafer overlay by co-analyzing the mask data and the wafer overlay data. To achieve the accurate cohesive results, we introduced the combined metrology mark which can be used for both mask registration measurement as well as for wafer overlay measurement. Coincidence of both metrology marks make it possible to subtract mask signature from wafer overlay without compromising the accuracy due to the physical distance between measurement marks, if we use 2 different marks for both metrologies. Therefore, it is possible to extract pure scanner related signatures, and to analyze the scanner related signatures in details to in order to enable root cause analysis and ultimately drive higher wafer yield. We determined the exact mask registration error in order to decompose wafer overlay into mask, scanner, process and metrology. We also studied the impact of pellicle mounting by comparison of mask registration measurement pre-pellicle mounting and post-pellicle mounting in this investigation.

  7. Advanced Mask Aligner Lithography (AMALITH)

    NASA Astrophysics Data System (ADS)

    Voelkel, Reinhard; Vogler, Uwe; Bramati, Arianna

    2015-03-01

    Mask aligner lithography is very attractive for less-critical lithography layers and is widely used for LED, display, CMOS image sensor, micro-fluidics and MEMS manufacturing. Mask aligner lithography is also a preferred choice the semiconductor back-end for 3D-IC, TSV interconnects, advanced packaging (AdP) and wafer-level-packaging (WLP). Mask aligner lithography is a mature technique based on shadow printing and has not much changed since the 1980s. In shadow printing lithography a geometric pattern is transferred by free-space propagation from a photomask to a photosensitive layer on a wafer. The inherent simplicity of the pattern transfer offers ease of operation, low maintenance, moderate capital expenditure, high wafers-per-hour (WPH) throughput, and attractive cost-of-ownership (COO). Advanced mask aligner lithography (AMALITH) comprises different measures to improve shadow printing lithography beyond current limits. The key enabling technology for AMALITH is a novel light integrator systems, referred to as MO Exposure Optics® (MOEO). MOEO allows to fully control and shape the properties of the illumination light in a mask aligner. Full control is the base for accurate simulation and optimization of the shadow printing process (computational lithography). Now photolithography enhancement techniques like customized illumination, optical proximity correction (OPC), phase masks (AAPSM), half-tone lithography and Talbot lithography could be used in mask aligner lithography. We summarize the recent progress in advanced mask aligner lithography (AMALITH) and discuss possible measures to further improve shadow printing lithography.

  8. Technical advance: identification of plant actin-binding proteins by F-actin affinity chromatography

    NASA Technical Reports Server (NTRS)

    Hu, S.; Brady, S. R.; Kovar, D. R.; Staiger, C. J.; Clark, G. B.; Roux, S. J.; Muday, G. K.

    2000-01-01

    Proteins that interact with the actin cytoskeleton often modulate the dynamics or organization of the cytoskeleton or use the cytoskeleton to control their localization. In plants, very few actin-binding proteins have been identified and most are thought to modulate cytoskeleton function. To identify actin-binding proteins that are unique to plants, the development of new biochemical procedures will be critical. Affinity columns using actin monomers (globular actin, G-actin) or actin filaments (filamentous actin, F-actin) have been used to identify actin-binding proteins from a wide variety of organisms. Monomeric actin from zucchini (Cucurbita pepo L.) hypocotyl tissue was purified to electrophoretic homogeneity and shown to be native and competent for polymerization to actin filaments. G-actin, F-actin and bovine serum albumin affinity columns were prepared and used to separate samples enriched in either soluble or membrane-associated actin-binding proteins. Extracts of soluble actin-binding proteins yield distinct patterns when eluted from the G-actin and F-actin columns, respectively, leading to the identification of a putative F-actin-binding protein of approximately 40 kDa. When plasma membrane-associated proteins were applied to these columns, two abundant polypeptides eluted selectively from the F-actin column and cross-reacted with antiserum against pea annexins. Additionally, a protein that binds auxin transport inhibitors, the naphthylphthalamic acid binding protein, which has been previously suggested to associate with the actin cytoskeleton, was eluted in a single peak from the F-actin column. These experiments provide a new approach that may help to identify novel actin-binding proteins from plants.

  9. Defect tolerant transmission lithography mask

    DOEpatents

    Vernon, Stephen P.

    2000-01-01

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

  10. Bacterial Actins? An Evolutionary Perspective

    NASA Technical Reports Server (NTRS)

    Doolittle, Russell F.; York, Amanda L.

    2003-01-01

    According to the conventional wisdom, the existence of a cytoskeleton in eukaryotes and its absence in prokaryotes constitute a fundamental divide between the two domains of life. An integral part of the dogma is that a cytoskeleton enabled an early eukaryote to feed upon prokaryotes, a consequence of which was the occasional endosymbiosis and the eventual evolution of organelles. Two recent papers present compelling evidence that actin, one of the principal components of a cytoskeleton, has a homolog in Bacteria that behaves in many ways like eukaryotic actin. Sequence comparisons reveml that eukaryotic actin and the bacterial homolog (mreB protein), unlike many other proteins common to eukaryotes and Bacteria, have very different and more highly extended evolutionary histories.

  11. Programmable RET Mask Layout Verification

    NASA Astrophysics Data System (ADS)

    Beale, Daniel F.; Mayhew, Jeffrey P.; Rieger, Michael L.; Tang, Zongwu

    2002-12-01

    Emerging resolution enhancement techniques (RET) and OPC are dramatically increasing the complexity of mask layouts and, in turn, mask verification. Mask shapes needed to achieve required results on the wafer diverge significantly from corresponding shapes in the physical design, and in some cases a single chip layer may be decomposed into two masks used in multiple exposures. The mask verification challenge is to certify that a RET-synthesized mask layout will produce an acceptable facsimile of the design intent expressed in the design layout. Furthermore costs, tradeoffs between mask-complexity, design intent, targeted process latitude, and other factors are playing a growing role in helping to control rising mask costs. All of these considerations must in turn be incorporated into the mask layout verification strategy needed for data prep sign-off. In this paper we describe a technique for assessing the lithographic quality of mask layouts for diverse RET methods while effectively accommodating various manufacturing objectives and specifications. It leverages the familiar DRC paradigm for identifying errors and producing DRC-like error shapes in its output layout. It integrates a unique concept of "check figures" - layer-based geometries that dictate where and how simulations of shapes on the wafer are to be compared to the original desired layout. We will show how this provides a highly programmable environment that makes it possible to engage in "compound" check strategies that vary based on design intent and adaptive simulation with multiple checks. Verification may be applied at the "go/no go" level or can be used to build a body of data for quantitative analysis of lithographic behavior at multiple process conditions or for specific user-defined critical features. In addition, we will outline automated methods that guide the selection of input parameters controlling specific verification strategies.

  12. Fascin regulates nuclear actin during Drosophila oogenesis.

    PubMed

    Kelpsch, Daniel J; Groen, Christopher M; Fagan, Tiffany N; Sudhir, Sweta; Tootle, Tina L

    2016-10-01

    Drosophila oogenesis provides a developmental system with which to study nuclear actin. During Stages 5-9, nuclear actin levels are high in the oocyte and exhibit variation within the nurse cells. Cofilin and Profilin, which regulate the nuclear import and export of actin, also localize to the nuclei. Expression of GFP-tagged Actin results in nuclear actin rod formation. These findings indicate that nuclear actin must be tightly regulated during oogenesis. One factor mediating this regulation is Fascin. Overexpression of Fascin enhances nuclear GFP-Actin rod formation, and Fascin colocalizes with the rods. Loss of Fascin reduces, whereas overexpression of Fascin increases, the frequency of nurse cells with high levels of nuclear actin, but neither alters the overall nuclear level of actin within the ovary. These data suggest that Fascin regulates the ability of specific cells to accumulate nuclear actin. Evidence indicates that Fascin positively regulates nuclear actin through Cofilin. Loss of Fascin results in decreased nuclear Cofilin. In addition, Fascin and Cofilin genetically interact, as double heterozygotes exhibit a reduction in the number of nurse cells with high nuclear actin levels. These findings are likely applicable beyond Drosophila follicle development, as the localization and functions of Fascin and the mechanisms regulating nuclear actin are widely conserved.

  13. Fascin regulates nuclear actin during Drosophila oogenesis.

    PubMed

    Kelpsch, Daniel J; Groen, Christopher M; Fagan, Tiffany N; Sudhir, Sweta; Tootle, Tina L

    2016-10-01

    Drosophila oogenesis provides a developmental system with which to study nuclear actin. During Stages 5-9, nuclear actin levels are high in the oocyte and exhibit variation within the nurse cells. Cofilin and Profilin, which regulate the nuclear import and export of actin, also localize to the nuclei. Expression of GFP-tagged Actin results in nuclear actin rod formation. These findings indicate that nuclear actin must be tightly regulated during oogenesis. One factor mediating this regulation is Fascin. Overexpression of Fascin enhances nuclear GFP-Actin rod formation, and Fascin colocalizes with the rods. Loss of Fascin reduces, whereas overexpression of Fascin increases, the frequency of nurse cells with high levels of nuclear actin, but neither alters the overall nuclear level of actin within the ovary. These data suggest that Fascin regulates the ability of specific cells to accumulate nuclear actin. Evidence indicates that Fascin positively regulates nuclear actin through Cofilin. Loss of Fascin results in decreased nuclear Cofilin. In addition, Fascin and Cofilin genetically interact, as double heterozygotes exhibit a reduction in the number of nurse cells with high nuclear actin levels. These findings are likely applicable beyond Drosophila follicle development, as the localization and functions of Fascin and the mechanisms regulating nuclear actin are widely conserved. PMID:27535426

  14. 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

  15. The reconstitution of actin polymerization on liposomes.

    PubMed

    Stamnes, Mark; Xu, Weidong

    2010-01-01

    Membrane-associated actin polymerization is of considerable interest due to its role in cell migration and the motility of intracellular organelles. Intensive research efforts are underway to investigate the physiological role of membrane-associated actin as well as the regulation and mechanics of actin assembly. Branched actin polymerization on membranes is catalyzed by the Arp2/3 complex. Signaling events leading to the activation of the guanosine triphosphate (GTP)-binding protein Cdc42 stimulate Arp2/3-dependent actin polymerization. We have studied the role of Cdc42 at the Golgi apparatus in part by reconstituting actin polymerization on isolated Golgi membranes and on liposomes. In this manner, we showed that cytosolic proteins are sufficient for actin assembly on a phospholipid bilayer. Here we describe methods for the cell-free reconstitution of membrane-associated actin polymerization using liposomes and brain cytosol.

  16. Dynamic actin structures stabilized by profilin.

    PubMed Central

    Finkel, T; Theriot, J A; Dise, K R; Tomaselli, G F; Goldschmidt-Clermont, P J

    1994-01-01

    We describe the production and analysis of clonal cell lines in which we have overexpressed human profilin, a small ubiquitous actin monomer binding protein, to assess the role of profilin on actin function in vivo. The concentration of filamentous actin is increased in cells with higher profilin levels, and actin filament half-life measured in these cells is directly proportional to the steady-state profilin concentration. The distribution of actin filaments is altered by profilin overexpression. While parallel actin bundles crossing the cells are virtually absent in cells overexpressing profilin, the submembranous actin network of these cells is denser than in control cells. These results suggest that in vivo profilin regulates the stability, and thereby distribution, of specific dynamic actin structures. Images PMID:8108438

  17. Bringing mask repair to the next level

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  18. [Masked hypertension: myth or reality?].

    PubMed

    Mallion, Jean-Michel; Ormezzano, Olivier; Barone-Rochette, Gilles; Neuder, Yannick; Salvat, Muriel; Baguet, Jean-Philippe

    2008-06-01

    Masked hypertension is also referred as reverse white coat hypertension. Masked hypertension is diagnosed in subjects who have normal clinic blood pressure (BP) <140/90 mmHg and elevated ambulatory BP or home BP, with daytime systolic BP> or = 135 mmHg or daytime diastolic BP > or = 85 mmHg. Its prevalence varies between 10 to at least 47% and differs substantially according to the reference population and the specific criteria.Subjects with masked hypertension have been shown to have more extensive target organ damage, specifically, a higher prevalence of carotid atherosclerosis and of left ventricular cardiac hypertrophy. Longitudinal studies of patients with masked hypertension show higher levels of cardiovascular morbidity and mortality than in reference populations. These studies show that ambulatory or home BP measurements predict risk much better than the usual clinical measurements and that those who are found to be hypertensive by ambulatory or home measurements have greater risks than those who are not. Who should be tested for masked hypertension? Our reference study shows that 3 characteristics are most likely to predict masked hypertension: male sex, age over 60 years, and office systolic BP of more than 130 mmHg. Masked hypertension is indeed a reality. Individual patients should be tested and treated, based on the physician's clinical judgment.

  19. Association of actin with alpha crystallins

    NASA Technical Reports Server (NTRS)

    Gopalakrishnan, S.; Boyle, D.; Takemoto, L.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    The alpha crystallins are cytosolic proteins that co-localize and co-purify with actin-containing microfilaments. Affinity column chromatography employing both covalently-coupled actin or alpha crystallin was used to demonstrate specific and saturable binding of actin with alpha crystallin. This conclusion was confirmed by direct visualization of alpha aggregates bound to actin polymerized in vitro. The significance of this interaction in relation to the functional properties of these two polypeptides will be discussed.

  20. Mask side wall clamping

    NASA Astrophysics Data System (ADS)

    Naaijkens, G. J. P.; Rosielle, P. C. J. N.; Steinbuch, M.

    2013-04-01

    Current state-of-the-art optical lithography scanners using 193nm wavelength lasers and numerical apertures of 1.35 have reached fundamental printing limits. Yet, consumer demands and device trends continue to drive smaller feature sizes, and most IC manufacturers have already navigated beyond the lithographic printing limits by turning to double patterning techniques.1 Requiring an extra lithography step for these techniques, it is essential to keep costs down by e.g. increasing wafer throughput. Currently, leading edge immersion scanners consistently produce over 190 wafers per hour (wph). However, to keep decreasing the cost per transistor, higher throughputs of 250 wph are key targets for the year 20132. Amongst others, higher throughput can be acquired by increasing acceleration of the positioning stages. One of the constraining technologies is the current mask or reticle clamping concept due to its friction based acceleration. While current reticle accelerations amount to 150 m/s2, some research3 has already been performed to reticle stage accelerations of 400 m/s2. In this paper, a novel reticle clamping concept is presented. The concept is shown to be suitable for accelerations larger than 400 m/s2 entirely eliminating reticle slip, whilst meeting specifications for clamping induced error with a pattern deformation of < 0.12 nm on wafer stage level (WS) and comprising high clamp stiffness.

  1. Hg-Mask Coronagraph

    NASA Astrophysics Data System (ADS)

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

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

  2. Ofsted Inspected

    ERIC Educational Resources Information Center

    Coffield, Frank

    2009-01-01

    One of the most radical actions one can take is to describe, without exaggeration or bias, exactly what is happening. The author has been reading the "Handbook for the inspection of further education and skills from September 2009." The Office for Standards in Education, Children's Services and Skills' (Ofsted's) new handbook promises a "fresh…

  3. Actin in hair cells and hearing loss.

    PubMed

    Drummond, Meghan C; Belyantseva, Inna A; Friderici, Karen H; Friedman, Thomas B

    2012-06-01

    Hereditary deafness is genetically heterogeneous such that mutations of many different genes can cause hearing loss. This review focuses on the evidence and implications that several of these deafness genes encode actin-interacting proteins or actin itself. There is a growing appreciation of the contribution of the actin interactome in stereocilia development, maintenance, mechanotransduction and malfunction of the auditory system.

  4. Yersinia effector YopO uses actin as bait to phosphorylate proteins that regulate actin polymerization

    PubMed Central

    Lee, Wei Lin; Grimes, Jonathan M; Robinson, Robert C

    2016-01-01

    Pathogenic Yersinia species evade host immune systems through the injection of Yersinia outer proteins (Yops) into phagocytic cells. One Yop, YopO, also known as YpkA, induces actin-filament disruption, impairing phagocytosis. Here we describe the X-ray structure of Yersinia enterocolitica YopO in complex with actin, which reveals that YopO binds to an actin monomer in a manner that blocks polymerization yet allows the bound actin to interact with host actin-regulating proteins. SILAC-MS and biochemical analyses confirm that actin-polymerization regulators such as VASP, EVL, WASP, gelsolin and the formin diaphanous 1 are directly sequestered and phosphorylated by YopO through formation of ternary complexes with actin. This leads to a model in which YopO at the membrane sequesters actin from polymerization while using the bound actin as bait to recruit, phosphorylate and misregulate host actin-regulating proteins to disrupt phagocytosis. PMID:25664724

  5. Yersinia effector YopO uses actin as bait to phosphorylate proteins that regulate actin polymerization.

    PubMed

    Lee, Wei Lin; Grimes, Jonathan M; Robinson, Robert C

    2015-03-01

    Pathogenic Yersinia species evade host immune systems through the injection of Yersinia outer proteins (Yops) into phagocytic cells. One Yop, YopO, also known as YpkA, induces actin-filament disruption, impairing phagocytosis. Here we describe the X-ray structure of Yersinia enterocolitica YopO in complex with actin, which reveals that YopO binds to an actin monomer in a manner that blocks polymerization yet allows the bound actin to interact with host actin-regulating proteins. SILAC-MS and biochemical analyses confirm that actin-polymerization regulators such as VASP, EVL, WASP, gelsolin and the formin diaphanous 1 are directly sequestered and phosphorylated by YopO through formation of ternary complexes with actin. This leads to a model in which YopO at the membrane sequesters actin from polymerization while using the bound actin as bait to recruit, phosphorylate and misregulate host actin-regulating proteins to disrupt phagocytosis.

  6. Measuring the Cold Mask Offset

    NASA Astrophysics Data System (ADS)

    Roye, E.; Krist, J.; Schultz, A. B.; Wiklind, T.

    2003-04-01

    An unexpected increase in measured thermal background during the Cycle 11 early calibration program caused speculation that the cold mask position could have shifted since Cycle 7. To address this concern, a single orbit NICMOS program was executed (Program ID: 9704) to obtain deep PSF images of the star LHS1846 in all three cameras. Analysis of this data using the Phase Retrieval software package revealed a minimal amount of cold mask shift since Cycle 7 and provided new, more accurate cold mask values for the Tiny Tim PSF modeling software. It was concluded that the cold mask position was not the cause of increased thermal background observed during the Cycle 11 early calibration program. Increased thermal background has since been determined to be the result of increased thermal load on the HST aft shroud due to the addition of ACS and NCS during SM3b.

  7. Automatic classification and accurate size measurement of blank mask defects

    NASA Astrophysics Data System (ADS)

    Bhamidipati, Samir; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter

    2015-07-01

    A blank mask and its preparation stages, such as cleaning or resist coating, play an important role in the eventual yield obtained by using it. Blank mask defects' impact analysis directly depends on the amount of available information such as the number of defects observed, their accurate locations and sizes. Mask usability qualification at the start of the preparation process, is crudely based on number of defects. Similarly, defect information such as size is sought to estimate eventual defect printability on the wafer. Tracking of defect characteristics, specifically size and shape, across multiple stages, can further be indicative of process related information such as cleaning or coating process efficiencies. At the first level, inspection machines address the requirement of defect characterization by detecting and reporting relevant defect information. The analysis of this information though is still largely a manual process. With advancing technology nodes and reducing half-pitch sizes, a large number of defects are observed; and the detailed knowledge associated, make manual defect review process an arduous task, in addition to adding sensitivity to human errors. Cases where defect information reported by inspection machine is not sufficient, mask shops rely on other tools. Use of CDSEM tools is one such option. However, these additional steps translate into increased costs. Calibre NxDAT based MDPAutoClassify tool provides an automated software alternative to the manual defect review process. Working on defect images generated by inspection machines, the tool extracts and reports additional information such as defect location, useful for defect avoidance[4][5]; defect size, useful in estimating defect printability; and, defect nature e.g. particle, scratch, resist void, etc., useful for process monitoring. The tool makes use of smart and elaborate post-processing algorithms to achieve this. Their elaborateness is a consequence of the variety and

  8. Mechanism of Actin-Based Motility

    NASA Astrophysics Data System (ADS)

    Pantaloni, Dominique; Le Clainche, Christophe; Carlier, Marie-France

    2001-05-01

    Spatially controlled polymerization of actin is at the origin of cell motility and is responsible for the formation of cellular protrusions like lamellipodia. The pathogens Listeria monocytogenes and Shigella flexneri, which undergo actin-based propulsion, are acknowledged models of the leading edge of lamellipodia. Actin-based motility of the bacteria or of functionalized microspheres can be reconstituted in vitro from only five pure proteins. Movement results from the regulated site-directed treadmilling of actin filaments, consistent with observations of actin dynamics in living motile cells and with the biochemical properties of the components of the synthetic motility medium.

  9. Subdivisions with infinitely supported mask

    NASA Astrophysics Data System (ADS)

    Li, Song; Pan, Yali

    2008-04-01

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

  10. Low-defect reflective mask blanks for extreme ultraviolet lithography

    SciTech Connect

    Burkhart, S C; Cerjarn, C; Kearney, P; Mirkarimi, P; Walton, C; Ray-Chaudhuri, A

    1999-03-11

    Extreme Ultraviolet Lithgraphy (EUVL) is an emerging technology for fabrication of sub-100 nm feature sizes on silicon, following the SIA roadmap well into the 21st century. The specific EUVL system described is a scanned, projection lithography system with a 4:1 reduction, using a laser plasma EUV source. The mask and all of the system optics are reflective, multilayer mirrors which function in the extreme ultraviolet at 13.4 nm wavelength. Since the masks are imaged to the wafer exposure plane, mask defects greater than 80% of the exposure plane CD (for 4:1 reduction) will in many cases render the mask useless, whereas intervening optics can have defects which are not a printing problem. For the 100 nm node, we must reduce defects to less than 0.01/cm² @ 80nm or larger to obtain acceptable mask production yields. We have succeeded in reducing the defects to less than 0.1/cm² for defects larger than 130 nm detected by visible light inspection tools, however our program goal is to achieve 0.01/cm² in the near future. More importantly though, we plan to have a detailed understanding of defect origination and the effect on multilayer growth in order to mitigate defects below the 10-2/cm² level on the next generation of mask blank deposition systems. In this paper we will discuss issues and results from the ion-beam multilayer deposition tool, details of the defect detection and characterization facility, and progress on defect printability modeling.

  11. Visual Masking During Pursuit Eye Movements

    ERIC Educational Resources Information Center

    White, Charles W.

    1976-01-01

    Visual masking occurs when one stimulus interferes with the perception of another stimulus. Investigates which matters more for visual masking--that the target and masking stimuli are flashed on the same part of the retina, or, that the target and mask appear in the same place. (Author/RK)

  12. The Meaning behind the Mask. [Lesson Plan].

    ERIC Educational Resources Information Center

    National Endowment for the Humanities (NFAH), Washington, DC.

    In this lesson plan, students explore the cultural significance of masks. After exploring the world of African masks and storytelling, they create masks that tell stories of their own. In these six lessons, students first recall contexts in which masks are worn in the United States, and then discuss their use in stories. Students then investigate…

  13. The actin of muscle and fibroblasts.

    PubMed Central

    Anderson, P J

    1976-01-01

    The isolation and quantification of an 18-residue peptide from the N-terminal region of chicken actin was used to quantify the amount of actin in acetone-dried powders of chicken breast muscle and chicken-embryo fibroblasts. Either isotope dilution or double labelling can be used for peptide quantification. About 17% of the protein of chicken breast muscle was estimated to be actin. However, only 0.25% of the protein of chicken-embryo fibroblasts was determined to be actin by quantification of this peptide. The actin content of fibroblasts may be low or the amino acid sequences of muscle and fibroblast actin may differ in the N-terminal region. The methodology used can be extended to examine whether other regions of muscle actin sequence are present in fibroblasts or other cell types. PMID:938480

  14. Quantifying actin wave modulation on periodic topography

    NASA Astrophysics Data System (ADS)

    Guven, Can; Driscoll, Meghan; Sun, Xiaoyu; Parker, Joshua; Fourkas, John; Carlsson, Anders; Losert, Wolfgang

    2014-03-01

    Actin is the essential builder of the cell cytoskeleton, whose dynamics are responsible for generating the necessary forces for the formation of protrusions. By exposing amoeboid cells to periodic topographical cues, we show that actin can be directionally guided via inducing preferential polymerization waves. To quantify the dynamics of these actin waves and their interaction with the substrate, we modify a technique from computer vision called ``optical flow.'' We obtain vectors that represent the apparent actin flow and cluster these vectors to obtain patches of newly polymerized actin, which represent actin waves. Using this technique, we compare experimental results, including speed distribution of waves and distance from the wave centroid to the closest ridge, with actin polymerization simulations. We hypothesize the modulation of the activity of nucleation promotion factors on ridges (elevated regions of the surface) as a potential mechanism for the wave-substrate coupling. Funded by NIH grant R01GM085574.

  15. Automatic classification and defect verification based on inspection technology with lithography simulation

    NASA Astrophysics Data System (ADS)

    Kato, Masaya; Inuzuka, Hideki; Kosuge, Takeshi; Yoshikawa, Shingo; Kanno, Kayoko; Imai, Hidemichi; Miyashita, Hiroyuki; Vacca, Anthony; Fiekowsky, Peter; Fiekowsky, Dan

    2015-10-01

    Even small defects on the main patterns can create killer defects on the wafer, whereas the same defect on or near the decorative patterns may be completely benign to the wafer functionality. This ambiguity often causes operators and engineers to put a mask "on hold" to be analyzed by an AIMS™ tool which slows the manufacturing time and increases mask cost. In order to streamline the process, mask shops need a reliable way to quickly identify the wafer impact of defects during mask inspection review reducing the number of defects requiring AIMS™ analysis. Source Mask Optimization (SMO) techniques are now common on sub 20nm node critical reticle patterns These techniques create complex reticle patterns which often makes it difficult for inspection tool operators to identify the desired wafer pattern from the surrounding nonprinting patterns in advanced masks such as SMO, Inverse Lithography Technology (ILT), Negative Tone Development (NTD). In this study, we have tested a system that generates aerial simulation images directly from the inspection tool images. The resulting defect dispositions from a program defect test mask along with numerous production mask defects have been compared to the dispositions attained from AIMS™ analysis. The results of our comparisons are presented, as well as the impact to mask shop productivity.

  16. Automated SEM metrology of wafers printed using a SCAA mask

    NASA Astrophysics Data System (ADS)

    Desai, Sunil; Ebihara, Takeaki; Levenson, David; White, Sylvia

    2002-07-01

    The massive amount of data necessary to qualify a new 100nm generation technology can be efficiency collected using a CD-SEM and analyzed using Klarity ProData. By comparing the linewidths, space widths, and pitches printed in resists with different focus, exposure does, and numerical aperture with the measured reticle parameters, one can be determine optimal processing conditions and the required biasing rules for the new technology. The Sidewall Chrome Alternating Aperture Mask, a next generation alternating phase shift mask structure, is especially suitable for this as all relevant mask features are visible from the top surface which, however, is not planar and thus can confuse optical mask inspection tools. Resist patterns with line-space pitches from 220nm to 800nm and isolated lines - as well as the reticle - were measured sing a KLA-Tencor 8250 CD-SEM and analyzed with ProData. At the isofocal dose, the 70nm line - 150nm space reticle pattern printed with equal 110 nm lines and spaces at NA equals 0.63 on a Canon FPA-5000 ES3 248 nm step and scan tool, with a process window that overlapped those of less dense approximately 100 nm features.

  17. Evidence for a species of nuclear actin distinct from cytoplasmic and muscles actins.

    PubMed

    Bremer, J W; Busch, H; Yeoman, L C

    1981-03-31

    Nuclear actin (protein BJ) has been isolated from the chromatin of Novikoff hepatoma ascites cells and purified to homogeneity by selective extraction, Sepharose CL-6B chromatography, and preparative polyacrylamide gel electrophoresis. A comparison of nuclear and cytoplasmic actins from Novikoff hepatoma cells and rabbit muscle actin was made by amino acid analysis, isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and two-dimensional peptide mapping procedures. By these criteria, all of the proteins compared are actins, but each is chemically distinct. It was concluded, therefore, that nuclear actin is similar to, but not identical with, cytoplasmic actin isolated from Novikoff hepatoma cells. A striking similarity in peptide charge and migration as shown by peptide map analysis was observed for nuclear and rabbit skeletal muscle actins. This may indicate that nuclear actin has the capacity for contractile function. In addition, the actins synthesized in Novikoff hepatoma cells may results from more than two structural genes.

  18. The mask of psychotic diagnoses.

    PubMed

    Garfield, David

    2003-01-01

    Chronic mental illness results in the patient becoming adhered to a DSM-IV diagnostic label. Over time, this diagnosis can expand and become a "mask" that invisibly covers over the true person of the patient. Most commonly, two things then occur. First, the outside world forgets that the patient is a person and family, friends, staff, and doctors begin to treat the patient according to the superficial aspects of what the mask of the diagnosis connotes, rather than connecting with the person struggling with the illness. Second and, perhaps, more insidious, is that the patient, who has been vulnerable and shattered by his or her experience and battle with the illness, adopts the mask as a kind of invisible protective shield. The task of making contact with the patient behind the mask of the diagnosis is therefore a formidable one for psychoanalysts and therapists and staff who work with seriously ill patients. Treatment must focus on the dual process of interfering with the patient's use of the diagnostic mask while, at the same time, making safe contact with the person of the patient behind the mask. A focus on affect can help achieve these dual goals. By utilizing Semrad's (Semrad and van Buskirk, 1969) method of noticing and asking about "feelings" as conveyed by hallucinations, delusions, or bodily sensations, a reliable relationship can evolve and the clinician can come to have an important "selfobject" (Kohut, 1971) meaning for the patient. By attuning to the patient's "vitality" affects (Stern, 1985), great stability and a new sense of "aliveness" is made possible to help the patient emerge from the deadening effects of the illness and the mask of the diagnosis. PMID:12722887

  19. Affinity chromatography of immobilized actin and myosin.

    PubMed Central

    Bottomley, R C; Trayer, I P

    1975-01-01

    Actin and myosin were immobilized by coupling them to agarose matrices. Both immobilized G-actin and immobilized myosin retain most of the properties of the proteins in free solution and are reliable over long periods of time. Sepharose-F-actin, under the conditions used in this study, has proved unstable and variable in its properties. Sepharose-G-actin columns were used to bind heavy meromyosin and myosin subfragment 1 specifically and reversibly. The interaction involved is sensitive to variation in ionic strength, such that myosin itself is not retained by the columns at the high salt concentration required for its complete solubilization. Myosin, rendered soluble at low ionic strength by polyalanylation, will interact successfully with the immobilized actin. The latter can distinguish between active and inactive fractions of the proteolytic and polyalanyl myosin derivatives, and was used in the preparation of these molecules. The complexes formed between the myosin derivatives and Sepharose-G-actin can be dissociated by low concentrations of ATP, ADP and pyrophosphate in both the presence and the absence of Mg2+. The G-actin columns were used to evaluate the results of chemical modifications of myosin subfragments on their interactions with actin. F-Actin in free solution is bound specifically and reversibly to columns of insolubilized myosin. Thus, with elution by either ATP or pyrophosphate, actin has been purified in one step from extracts of acetone-dried muscle powder. PMID:241335

  20. Cloud and Cloud Shadow Masking Using Multi-Temporal Cloud Masking Algorithm in Tropical Environmental

    NASA Astrophysics Data System (ADS)

    Candra, D. S.; Phinn, S.; Scarth, P.

    2016-06-01

    A cloud masking approach based on multi-temporal satellite images is proposed. The basic idea of this approach is to detect cloud and cloud shadow by using the difference reflectance values between clear pixels and cloud and cloud shadow contaminated pixels. Several bands of satellite image which have big difference values are selected for developing Multi-temporal Cloud Masking (MCM) algorithm. Some experimental analyses are conducted by using Landsat-8 images. Band 3 and band 4 are selected because they can distinguish between cloud and non cloud. Afterwards, band 5 and band 6 are used to distinguish between cloud shadow and clear. The results show that the MCM algorithm can detect cloud and cloud shadow appropriately. Moreover, qualitative and quantitative assessments are conducted using visual inspections and confusion matrix, respectively, to evaluate the reliability of this algorithm. Comparison between this algorithm and QA band are conducted to prove the reliability of the approach. The results show that MCM better than QA band and the accuracy of the results are very high.

  1. Optical inspection system for cylindrical objects

    DOEpatents

    Brenden, Byron B.; Peters, Timothy J.

    1989-01-01

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

  2. Multiple actin binding domains of Ena/VASP proteins determine actin network stiffening.

    PubMed

    Gentry, Brian S; van der Meulen, Stef; Noguera, Philippe; Alonso-Latorre, Baldomero; Plastino, Julie; Koenderink, Gijsje H

    2012-11-01

    Vasodilator-stimulated phosphoprotein (Ena/VASP) is an actin binding protein, important for actin dynamics in motile cells and developing organisms. Though VASP's main activity is the promotion of barbed end growth, it has an F-actin binding site and can form tetramers, and so could additionally play a role in actin crosslinking and bundling in the cell. To test this activity, we performed rheology of reconstituted actin networks in the presence of wild-type VASP or mutants lacking the ability to tetramerize or to bind G-actin and/or F-actin. We show that increasing amounts of wild-type VASP increase network stiffness up to a certain point, beyond which stiffness actually decreases with increasing VASP concentration. The maximum stiffness is 10-fold higher than for pure actin networks. Confocal microscopy shows that VASP forms clustered actin filament bundles, explaining the reduction in network elasticity at high VASP concentration. Removal of the tetramerization site results in significantly reduced bundling and bundle clustering, indicating that VASP's flexible tetrameric structure causes clustering. Removing either the F-actin or the G-actin binding site diminishes VASP's effect on elasticity, but does not eliminate it. Mutating the F-actin and G-actin binding site together, or mutating the F-actin binding site and saturating the G-actin binding site with monomeric actin, eliminates VASP's ability to increase network stiffness. We propose that, in the cell, VASP crosslinking confers only moderate increases in linear network elasticity, and unlike other crosslinkers, VASP's network stiffening activity may be tuned by the local concentration of monomeric actin.

  3. EUV mask particle adders during scanner exposure

    NASA Astrophysics Data System (ADS)

    Hyun, Yoonsuk; Kim, Jinsoo; Kim, Kyuyoung; Koo, Sunyoung; Kim, SeoMin; Kim, Youngsik; Lim, Changmoon; Kwak, Nohjung

    2015-03-01

    As EUV reaches high volume manufacturing, scanner source power and reticle defectivity attract a lot of attention. Keeping a EUV mask clean after mask production is as essential as producing a clean EUV mask. Even though EUV pellicle is actively investigated, we might expose EUV masks without EUV pellicle for some time. To keep clean EUV mask under pellicle-less lithography, EUV scanner cleanliness needs to meet the requirement of high volume manufacturing. In this paper, we will show the cleanliness of EUV scanners in view of mask particle adders during scanner exposure. From this we will find several tendencies of mask particle adders depending on mask environment in scanner. Further we can categorize mask particle adders, which could show the possible causes of particle adders during exposure in scanners.

  4. Accurate mask model for advanced nodes

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  5. Informational masking and musical training.

    PubMed

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

    2003-09-01

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

  6. Informational masking and musical training

    NASA Astrophysics Data System (ADS)

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

    2003-09-01

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

  7. Psychometric functions for informational masking

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

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

  8. Production mask composition checking flow

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  9. The actin cytoskeleton in endothelial cell phenotypes

    PubMed Central

    Prasain, Nutan; Stevens, Troy

    2009-01-01

    Endothelium forms a semi-permeable barrier that separates blood from the underlying tissue. Barrier function is largely determined by cell-cell and cell-matrix adhesions that define the limits of cell borders. Yet, such cell-cell and cell-matrix tethering is critically reliant upon the nature of adherence within the cell itself. Indeed, the actin cytoskeleton fulfills this essential function, to provide a strong, dynamic intracellular scaffold that organizes integral membrane proteins with the cell’s interior, and responds to environmental cues to orchestrate appropriate cell shape. The actin cytoskeleton is comprised of three distinct, but interrelated structures, including actin cross-linking of spectrin within the membrane skeleton, the cortical actin rim, and actomyosin-based stress fibers. This review addresses each of these actin-based structures, and discusses cellular signals that control the disposition of actin in different endothelial cell phenotypes. PMID:19028505

  10. Inspection and repair for imprint lithography at 32 nm and below

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Sreenivasan, S. V.; Resnick, Douglas J.; Pritschow, Marcus; Butschke, Joerg; Irmscher, Mathias; Sailer, Holger; Dobberstein, Harald

    2009-04-01

    Step and Flash Imprint involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the progress made in inspection and repair of 1X imprint masks A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. These defects were then inspected using three different electron beam inspection systems. Defect sizes as small as 8 nm were detected, and detection limits were found to be a function of defect type. Both subtractive and additive repairs were attempted on SRAM Metal 1 cells. Repairs as small as 32nm were demonstrated, and the repair process was successfully tested for several hundreds of imprints.

  11. Filopodia-like actin cables position nuclei in association with perinuclear actin in Drosophila nurse cells.

    PubMed

    Huelsmann, Sven; Ylänne, Jari; Brown, Nicholas H

    2013-09-30

    Controlling the position of the nucleus is vital for a number of cellular processes from yeast to humans. In Drosophila nurse cells, nuclear positioning is crucial during dumping, when nurse cells contract and expel their contents into the oocyte. We provide evidence that in nurse cells, continuous filopodia-like actin cables, growing from the plasma membrane and extending to the nucleus, achieve nuclear positioning. These actin cables move nuclei away from ring canals. When nurse cells contract, actin cables associate laterally with the nuclei, in some cases inducing nuclear turning so that actin cables become partially wound around the nuclei. Our data suggest that a perinuclear actin meshwork connects actin cables to nuclei via actin-crosslinking proteins such as the filamin Cheerio. We provide a revised model for how actin structures position nuclei in nurse cells, employing evolutionary conserved machinery.

  12. Persistent nuclear actin filaments inhibit transcription by RNA polymerase II.

    PubMed

    Serebryannyy, Leonid A; Parilla, Megan; Annibale, Paolo; Cruz, Christina M; Laster, Kyle; Gratton, Enrico; Kudryashov, Dmitri; Kosak, Steven T; Gottardi, Cara J; de Lanerolle, Primal

    2016-09-15

    Actin is abundant in the nucleus and it is clear that nuclear actin has important functions. However, mystery surrounds the absence of classical actin filaments in the nucleus. To address this question, we investigated how polymerizing nuclear actin into persistent nuclear actin filaments affected transcription by RNA polymerase II. Nuclear filaments impaired nuclear actin dynamics by polymerizing and sequestering nuclear actin. Polymerizing actin into stable nuclear filaments disrupted the interaction of actin with RNA polymerase II and correlated with impaired RNA polymerase II localization, dynamics, gene recruitment, and reduced global transcription and cell proliferation. Polymerizing and crosslinking nuclear actin in vitro similarly disrupted the actin-RNA-polymerase-II interaction and inhibited transcription. These data rationalize the general absence of stable actin filaments in mammalian somatic nuclei. They also suggest a dynamic pool of nuclear actin is required for the proper localization and activity of RNA polymerase II.

  13. Improving inspectability with KLA-Tencor TeraScan thin line de-sense

    NASA Astrophysics Data System (ADS)

    Chen, Chunlin; Kim, David; Park, Ki Hun; Kim, NamWook; Han, Sang Hoon; Park, Jin Hyung; Chung, Dong Hoon

    2007-10-01

    In the ever-changing semi-conductor industry, new innovations and technical advances constantly bring new challenges to fabs, mask-shops and vendors. One of such advances is an aggressive optical proximity correction (OPC) method, sub-resolution assist features (SRAF). On one hand, SRAFs bring a leap forward in resolution improvement during wafer printing; on the other hand they bring new challenges to many processes in mask making. KLA-Tencor Corp. working together with Samsung Electronics Co. developed an additional function to the current HiRes 1 detector to increase inspectability and usable sensitivity during the inspection step of the mask making process. SRAFs bring an unique challenge to the mask inspection process, which mask shops had not experienced before. SRAF by nature do not resolve on wafer and thus have a higher tolerance in the CD (critical dimension) uniformity, edge roughness and pattern defects. This new function, Thin-Line De-sense (TLD), increase the inspectability and usable sensitivity by generating different regions of sensitivity and thus will match the defect requirement on a particular photomask with SRAFs better. The value of TLD was proven in a production setting with more than 30 masks inspected, and resulted in higher sensitivity on main features and a sharp decrease in the amount of defects that needed to be classified.

  14. Stochastic model of profilin-actin polymerization

    NASA Astrophysics Data System (ADS)

    Horan, Brandon; Vavylonis, Dimitrios

    A driving factor in cell motility and other processes that involve changes of cell shape is the rapid polymerization of actin subunits into long filaments. This process is regulated by profilin, a protein which binds to actin subunits and regulates elongation of actin filaments. Whether profilin stimulates polymerization by coupling to hydrolysis of ATP-bound actin is debated. Previous studies have proposed indirect coupling to ATP hydrolysis using rate equations, but did not include the effects of fluctuations that are important near the critical concentration. We developed stochastic simulations using the Gillespie algorithm to study single filament elongation at the barbed end in the presence of profilin. We used recently measured rate constants and estimated the rate of profilin binding to the barbed end such that detailed balance is satisfied. Fast phosphate release at the tip of the filament was accounted for. The elongation rate and length diffusivity as functions of profilin and actin concentration were calculated and used to extract the critical concentrations of free actin and of total actin. We show under what conditions profilin leads to an increase in the critical concentration of total actin but a decrease in the critical concentration of free actin.

  15. Contribution of nuclear actin to transcription regulation.

    PubMed

    Yamazaki, Shota; Yamamoto, Koji; Harata, Masahiko

    2015-06-01

    Actin, an integral component of the cytoskeleton, plays crucial roles in a variety of cell functions, including cell migration, adhesion, polarity and shape change. Studies performed during the last couple of decades have revealed that the actin also exists in the nucleus. However, the function and properties of nuclear actin remained elusive so far. Recently, we showed that an actin tagged with EYFP and fused with a nuclear localization signal (EYFP-NLS-actin) formed visible filamentous (F)-actin bundles in cells. To obtain further details about the individual genes that are affected by the nuclear actin, we have used the microarray analysis to determine the changes in the expression levels of RNAs in HeLa cells as a result of EYFP-NLS-actin expression. Our results suggest that the nuclear actin plays a role in the activation of genes rather than their repression. The data has been deposited in the Gene Expression Omnibus (GEO) database under the accession number GSE59799.

  16. Phosphorylation and actin activation of brain myosin.

    PubMed Central

    Barylko, B; Sobieszek, A

    1983-01-01

    A method is described for obtaining brain myosin that shows significant actin activation, after phosphorylation with chicken gizzard myosin light chain kinase. Myosin with this activity could be obtained only via the initial purification of brain actomyosin. The latter complex, isolated by a method similar to that used for smooth muscle, contained actin, myosin, tropomyosin of the non-muscle type and another actin-binding protein of approximately 100,000 daltons. From the presence of a specific myosin light chain kinase and phosphatase in brain tissue it is suggested that the regulation of actin-myosin interaction operates via phosphorylation and dephosphorylation of myosin. Images Fig. 1. Fig. 3. PMID:11894951

  17. Architecture and Connectivity Govern Actin Network Contractility.

    PubMed

    Ennomani, Hajer; Letort, Gaëlle; Guérin, Christophe; Martiel, Jean-Louis; Cao, Wenxiang; Nédélec, François; De La Cruz, Enrique M; Théry, Manuel; Blanchoin, Laurent

    2016-03-01

    Actomyosin contractility plays a central role in a wide range of cellular processes, including the establishment of cell polarity, cell migration, tissue integrity, and morphogenesis during development. The contractile response is variable and depends on actomyosin network architecture and biochemical composition. To determine how this coupling regulates actomyosin-driven contraction, we used a micropatterning method that enables the spatial control of actin assembly. We generated a variety of actin templates and measured how defined actin structures respond to myosin-induced forces. We found that the same actin filament crosslinkers either enhance or inhibit the contractility of a network, depending on the organization of actin within the network. Numerical simulations unified the roles of actin filament branching and crosslinking during actomyosin contraction. Specifically, we introduce the concept of "network connectivity" and show that the contractions of distinct actin architectures are described by the same master curve when considering their degree of connectivity. This makes it possible to predict the dynamic response of defined actin structures to transient changes in connectivity. We propose that, depending on the connectivity and the architecture, network contraction is dominated by either sarcomeric-like or buckling mechanisms. More generally, this study reveals how actin network contractility depends on its architecture under a defined set of biochemical conditions.

  18. F-actin waves, actin cortex disassembly and focal exocytosis driven by actin-phosphoinositide positive feedback.

    PubMed

    Masters, Thomas A; Sheetz, Michael P; Gauthier, Nils C

    2016-04-01

    Actin polymerization is controlled by the phosphoinositide composition of the plasma membrane. However, the molecular mechanisms underlying the spatiotemporal regulation of actin network organization over extended length scales are still unclear. To observe phosphoinositide-dependent cytoskeletal dynamics we combined the model system of frustrated phagocytosis, total internal reflection microscopy and manipulation of the buffer tonicity. We found that macrophages interacting with IgG-coated glass substrates formed circular F-actin waves on their ventral surface enclosing a region of plasma membrane devoid of cortical actin. Plasma membrane free of actin cortex was strongly depleted of PI(4,5)P2 , but enriched in PI(3,4)P2 and displayed a fivefold increase in exocytosis. Wave formation could be promoted by application of a hypotonic shock. The actin waves were characteristic of a bistable wavefront at the boundary between the regions of membrane containing and lacking cortical actin. Phosphoinositide modifiers and RhoGTPase activities dramatically redistributed with respect to the wavefronts, which often exhibited spatial oscillations. Perturbation of either lipid or actin cytoskeleton-related pathways led to rapid loss of both the polarized lipid distribution and the wavefront. As waves travelled over the plasma membrane, wavefront actin was seen to rapidly polymerize and depolymerize at pre-existing clusters of FcγRIIA, coincident with rapid changes in lipid composition. Thus the potential of receptors to support rapid F-actin polymerization appears to depend acutely on the local concentrations of multiple lipid species. We propose that interdependence through positive feedback from the cytoskeleton to lipid modifiers leads to coordinated local cortex remodeling, focal exocytosis, and organizes extended actin networks. PMID:26915738

  19. F-actin waves, actin cortex disassembly and focal exocytosis driven by actin-phosphoinositide positive feedback.

    PubMed

    Masters, Thomas A; Sheetz, Michael P; Gauthier, Nils C

    2016-04-01

    Actin polymerization is controlled by the phosphoinositide composition of the plasma membrane. However, the molecular mechanisms underlying the spatiotemporal regulation of actin network organization over extended length scales are still unclear. To observe phosphoinositide-dependent cytoskeletal dynamics we combined the model system of frustrated phagocytosis, total internal reflection microscopy and manipulation of the buffer tonicity. We found that macrophages interacting with IgG-coated glass substrates formed circular F-actin waves on their ventral surface enclosing a region of plasma membrane devoid of cortical actin. Plasma membrane free of actin cortex was strongly depleted of PI(4,5)P2 , but enriched in PI(3,4)P2 and displayed a fivefold increase in exocytosis. Wave formation could be promoted by application of a hypotonic shock. The actin waves were characteristic of a bistable wavefront at the boundary between the regions of membrane containing and lacking cortical actin. Phosphoinositide modifiers and RhoGTPase activities dramatically redistributed with respect to the wavefronts, which often exhibited spatial oscillations. Perturbation of either lipid or actin cytoskeleton-related pathways led to rapid loss of both the polarized lipid distribution and the wavefront. As waves travelled over the plasma membrane, wavefront actin was seen to rapidly polymerize and depolymerize at pre-existing clusters of FcγRIIA, coincident with rapid changes in lipid composition. Thus the potential of receptors to support rapid F-actin polymerization appears to depend acutely on the local concentrations of multiple lipid species. We propose that interdependence through positive feedback from the cytoskeleton to lipid modifiers leads to coordinated local cortex remodeling, focal exocytosis, and organizes extended actin networks.

  20. Multiple-mask chemical etching

    NASA Technical Reports Server (NTRS)

    Cannon, D. L.

    1969-01-01

    Multiple masking techniques use lateral etching to reduce the total area of the high etch-rate oxide exposed to the chemical etchant. One method uses a short-term etch to remove the top layer from the silicon oxide surface, another acts before the top layer is grown.

  1. Process optimization for mask fabrication

    NASA Astrophysics Data System (ADS)

    Sakurai, Hideaki; Itoh, Masamitsu; Kumagae, Akitoshi; Anze, Hirohito; Abe, Takayuki; Higashikawa, Iwao

    1998-09-01

    Recently, next-generation mask fabrication processes have been actively examined for application with Electron Beam writing tools and chemically amplified resists. In this study, we used a variable shaped electron beam writing system with an accelerating voltage and chemically amplified resist to investigate the dependence of the CD error in a localized area of a 6025 mask on the process factors, with the goal of fabricating more accurate masks with improving sensitivity. Our results indicated that CD error in a localized area did not depend on the resist thickness. Higher sensitivity and CD uniformity were achieved simultaneously. Moreover, we could isolate the CD error caused by the resist heating effect is more apparent for higher doses than lower doses. However, a higher dose gives rise to a small CD change rate. In this experiment, the effect of the lower CD change rate at a higher dose counterbalances the resist heating effect. By decreasing CD error in a localized area, we obtained a CD uniformity of 14 nm in a 100 mm area on the mask.

  2. The pros and cons of common actin labeling tools for visualizing actin dynamics during Drosophila oogenesis

    PubMed Central

    Spracklen, Andrew J.; Fagan, Tiffany N.; Lovander, Kaylee E.; Tootle, Tina L.

    2015-01-01

    Dynamic remodeling of the actin cytoskeleton is required for both development and tissue homeostasis. While fixed image analysis has provided significant insight into such events, a complete understanding of cytoskeletal dynamics requires live imaging. Numerous tools for the live imaging of actin have been generated by fusing the actin-binding domain from an actin-interacting protein to a fluorescent protein. Here we comparatively assess the utility of three such tools – Utrophin, Lifeact, and F-tractin – for characterizing the actin remodeling events occurring within the germline-derived nurse cells during Drosophila mid-oogenesis or follicle development. Specifically, we used the UAS/GAL4 system to express these tools at different levels and in different cells, and analyzed these tools for effects on fertility, alterations in the actin cytoskeleton, and ability to label filamentous actin (F-actin) structures by both fixed and live imaging. While both Utrophin and Lifeact robustly label F-actin structures within the Drosophila germline, when strongly expressed they cause sterility and severe actin defects including cortical actin breakdown resulting in multi-nucleate nurse cells, early F-actin filament and aggregate formation during stage 9 (S9), and disorganized parallel actin filament bundles during stage 10B (S10B). However, by using a weaker germline GAL4 driver in combination with a higher temperature, Utrophin can label F-actin with minimal defects. Additionally, strong Utrophin expression within the germline causes F-actin formation in the nurse cell nuclei and germinal vesicle during mid-oogenesis. Similarly, Lifeact expression results in nuclear F-actin only within the germinal vesicle. F-tractin expresses at a lower level than the other two labeling tools, but labels cytoplasmic F-actin structures well without causing sterility or striking actin defects. Together these studies reveal how critical it is to evaluate the utility of each actin labeling

  3. The pros and cons of common actin labeling tools for visualizing actin dynamics during Drosophila oogenesis.

    PubMed

    Spracklen, Andrew J; Fagan, Tiffany N; Lovander, Kaylee E; Tootle, Tina L

    2014-09-15

    Dynamic remodeling of the actin cytoskeleton is required for both development and tissue homeostasis. While fixed image analysis has provided significant insight into such events, a complete understanding of cytoskeletal dynamics requires live imaging. Numerous tools for the live imaging of actin have been generated by fusing the actin-binding domain from an actin-interacting protein to a fluorescent protein. Here we comparatively assess the utility of three such tools--Utrophin, Lifeact, and F-tractin--for characterizing the actin remodeling events occurring within the germline-derived nurse cells during Drosophila mid-oogenesis or follicle development. Specifically, we used the UAS/GAL4 system to express these tools at different levels and in different cells, and analyzed these tools for effects on fertility, alterations in the actin cytoskeleton, and ability to label filamentous actin (F-actin) structures by both fixed and live imaging. While both Utrophin and Lifeact robustly label F-actin structures within the Drosophila germline, when strongly expressed they cause sterility and severe actin defects including cortical actin breakdown resulting in multi-nucleate nurse cells, early F-actin filament and aggregate formation during stage 9 (S9), and disorganized parallel actin filament bundles during stage 10B (S10B). However, by using a weaker germline GAL4 driver in combination with a higher temperature, Utrophin can label F-actin with minimal defects. Additionally, strong Utrophin expression within the germline causes F-actin formation in the nurse cell nuclei and germinal vesicle during mid-oogenesis. Similarly, Lifeact expression results in nuclear F-actin only within the germinal vesicle. F-tractin expresses at a lower level than the other two labeling tools, but labels cytoplasmic F-actin structures well without causing sterility or striking actin defects. Together these studies reveal how critical it is to evaluate the utility of each actin labeling tool

  4. "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…

  5. Force of an actin spring

    NASA Astrophysics Data System (ADS)

    Shin, Jennifer; Mahadevan, L.; Matsudaira, Paul

    2003-03-01

    The acrosomal process of the horseshoe crab sperm is a novel mechanochemical molecular spring that converts its elastic stain energy to mechanical work upon the chemical activation by Ca2+. Twisted and bent, the initial state of the acrosomal bundle features a high degree of complexity in its structure and the energy is believed to be stored in the highly strained actin filaments as an elastic potential energy. When activated, the bundle relaxes from the coil of the highly twisted and bent filaments to its straight conformation at a mean velocity of 15um/s. The mean extension velocity increases dramatically from 3um/s to 27um/s when temperature of the medium is changed from 9.6C to 32C (respective viscosities of 1.25-0.75cp), yet it exhibits a very weak dependence on changes in the medium viscosity (1cp-33cp). These experiments suggest that the uncoiling of the actin spring should be limited not by the viscosity of the medium but by the unlatching events of involved proteins at a molecular level. Unlike the viscosity-limited processes, where force is directly related to the rate of the reaction, a direct measurement is required to obtain the spring force of the acrosomal process. The extending acrosomal bundle is forced to push against a barrier and its elastic buckling response is analyzed to measure the force generated during the uncoiling.

  6. Vertical Feature Mask Feature Classification Flag Extraction

    Atmospheric Science Data Center

    2013-03-28

      Vertical Feature Mask Feature Classification Flag Extraction This routine demonstrates extraction of the ... in a CALIPSO Lidar Level 2 Vertical Feature Mask feature classification flag value. It is written in Interactive Data Language (IDL) ...

  7. Physiological functioning of the ear and masking

    NASA Technical Reports Server (NTRS)

    1984-01-01

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

  8. Effect of alpha-actinin on actin structure. Actin ATPase activity.

    PubMed

    Singh, I; Goll, D E; Robson, R M

    1981-08-28

    Alpha-Actinin increases the ATPase activity of actin by up to 84%, depending un pH, divalent cations present and the added Mg2+: ATP ratio. Dithiothreitol decreases actin ATPase activity approx. 20% but does not reduce the ability of alpha-actinin to increase actin ATP activity. Increasing amounts of added alpha-actinin up to 1 mos alpha-actinin to 49 mol actin cause in increasing increment in actin ATPase activity, but adding alpha-actinin beyond 1 mol alpha-actinin to 49 mol actin elicits only small additional increments in activity. Actin ATPase activity ranges from approx 100 nmol Pi/mg actin per h (4.3 mol Pi/mol actin per h) at high levels (10 mM) of ATP in the presence of lower amounts (1 mM) of added mg2+ to approx. 12.5 nmol Pi/mg actin per h (0.52 mol Pi/mol actin per h) at high pH (8.5) or at low levels (0.5-1.0 mM) of ATP in the presence of higher amounts (10 mM) of added Mg2+ ATp uncomplexed with Mg2+ inhibits the ability of alpha-actinin to increase F-actin ATPase activity. Activities with different divalent cations showed that the actin ATPase in these studies, which was 1/100 as great as Mg2+-modified actomyosin ATPase activity, was not due to trace amounts of myosin contaminating the actin preparations. The results are consistent with the concept that alpha-actinin can alter the structure of actin monomers. PMID:6456018

  9. Change in the actin-myosin subfragment 1 interaction during actin polymerization.

    PubMed

    Chaussepied, P; Kasprzak, A A

    1989-12-01

    To better characterize the conformational differences of G- and F-actin, we have compared the interaction between G- and F-actin with myosin subfragment 1 (S1) which had part of its F-actin binding site (residues 633-642) blocked by a complementary peptide or "antipeptide" (Chaussepied, P., and Morales, M. F. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 7471-7475). Light scattering, sedimentation, and electron microscopy measurements showed that, with the antipeptide covalently attached to the S1 heavy chain, S1 was not capable of inducing G-actin polymerization in the absence of salt. Moreover, the antipeptide-carrying S1 did not change the fluorescence polarization of 5-[2-(iodoacetyl)-aminoethyl]aminonaphthalene-1-sulfonic acid (1,5-IAEDANS)-labeled G-actin or of 1,5-IAEDANS-labeled actin dimer, compared to the control S1. This result, interpreted as a lack of interaction between G-actin and antipeptide-carrying S1, was confirmed further by the following experiments: in the presence of G-actin, antipeptide.S1 heavy chain was not protected against trypsin and papain proteolysis, and G-actin could not be cross-linked to antipeptide.S1 by 1-ethyl-3[-3-(dimethylamino)propyl]carbodiimide. In contrast, similar experiments showed that antipeptide.S1 was able to interact with nascent F-actin and with F-actin. Thus, blocking the stretch 633-642 of S1 heavy chain by the antipeptide strongly inhibits G-actin-S1 interaction but only slightly alters F-actin-S1 contact. We, therefore postulate that this stretch of skeletal S1 heavy chain is essential for G-actin-S1 interaction and that the G-F transformation generates new S1 binding site(s) on the actin molecule.

  10. Unconventional actin conformations localize on intermediate filaments in mitosis

    SciTech Connect

    Hubert, Thomas; Vandekerckhove, Joel; Gettemans, Jan

    2011-03-04

    Research highlights: {yields} Unconventional actin conformations colocalize with vimentin on a cage-like structure in metaphase HEK 293T cells. {yields} These conformations are detected with the anti-actin antibodies 1C7 ('lower dimer') and 2G2 ('nuclear actin'), but not C4 (monomeric actin). {yields} Mitotic unconventional actin cables are independent of filamentous actin or microtubules. {yields} Unconventional actin colocalizes with vimentin on a nocodazole-induced perinuclear dense mass of cables. -- Abstract: Different structural conformations of actin have been identified in cells and shown to reside in distinct subcellular locations of cells. In this report, we describe the localization of actin on a cage-like structure in metaphase HEK 293T cells. Actin was detected with the anti-actin antibodies 1C7 and 2G2, but not with the anti-actin antibody C4. Actin contained in this structure is independent of microtubules and actin filaments, and colocalizes with vimentin. Taking advantage of intermediate filament collapse into a perinuclear dense mass of cables when microtubules are depolymerized, we were able to relocalize actin to such structures. We hypothesize that phosphorylation of intermediate filaments at mitosis entry triggers the recruitment of different actin conformations to mitotic intermediate filaments. Storage and partition of the nuclear actin and antiparallel 'lower dimer' actin conformations between daughter cells possibly contribute to gene transcription and transient actin filament dynamics at G1 entry.

  11. Synthetic peptides that cause F-actin bundling and block actin depolymerization

    DOEpatents

    Sederoff, Heike; Huber, Steven C; Larabell, Carolyn A

    2011-10-18

    Synthetic peptides derived from sucrose synthase, and having homology to actin and actin-related proteins, sharing a common motif, useful for causing acting bundling and preventing actin depolymerization. Peptides exhibiting the common motif are described, as well as specific synthetic peptides which caused bundled actin and inhibit actin depolymerization. These peptides can be useful for treating a subject suffering from a disease characterized by cells having neoplastic growth, for anti-cancer therapeutics, delivered to subjects solely, or concomitantly or sequentially with other known cancer therapeutics. These peptides can also be used for stabilizing microfilaments in living cells and inhibiting growth of cells.

  12. Refilins are short-lived Actin-bundling proteins that regulate lamellipodium protrusion dynamics

    PubMed Central

    Gay, Olivia; Gilquin, Benoît; Assard, Nicole; Stuelsatz, Pascal; Delphin, Christian; Lachuer, Joël; Gidrol, Xavier; Baudier, Jacques

    2016-01-01

    ABSTRACT Refilins (RefilinA and RefilinB) are members of a novel family of Filamin binding proteins that function as molecular switches to conformationally alter the Actin filament network into bundles. We show here that Refilins are extremely labile proteins. An N-terminal PEST/DSG(X)2-4S motif mediates ubiquitin-independent rapid degradation. A second degradation signal is localized within the C-terminus. Only RefilinB is protected from rapid degradation by an auto-inhibitory domain that masks the PEST/DSG(X)2-4S motif. Dual regulation of RefilinA and RefilinB stability was confirmed in rat brain NG2 precursor cells (polydendrocyte). Using loss- and gain-of-function approaches we show that in these cells, and in U373MG cells, Refilins contribute to the dynamics of lamellipodium protrusion by catalysing Actin bundle formation within the lamella Actin network. These studies extend the Actin bundling function of the Refilin-Filamin complex to dynamic regulation of cell membrane remodelling. PMID:27744291

  13. Method for mask repair using defect compensation

    DOEpatents

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

    2001-01-01

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

  14. 21 CFR 868.5600 - Venturi mask.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  15. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a...

  16. 21 CFR 868.5600 - Venturi mask.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Venturi mask. 868.5600 Section 868.5600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5600 Venturi mask. (a) Identification. A venturi mask is...

  17. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a...

  18. 21 CFR 868.5600 - Venturi mask.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Venturi mask. 868.5600 Section 868.5600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5600 Venturi mask. (a) Identification. A venturi mask is...

  19. 21 CFR 868.5600 - Venturi mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  20. 21 CFR 868.5600 - Venturi mask.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Venturi mask. 868.5600 Section 868.5600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5600 Venturi mask. (a) Identification. A venturi mask is...

  1. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a...

  2. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a...

  3. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a...

  4. Profilin connects actin assembly with microtubule dynamics.

    PubMed

    Nejedla, Michaela; Sadi, Sara; Sulimenko, Vadym; de Almeida, Francisca Nunes; Blom, Hans; Draber, Pavel; Aspenström, Pontus; Karlsson, Roger

    2016-08-01

    Profilin controls actin nucleation and assembly processes in eukaryotic cells. Actin nucleation and elongation promoting factors (NEPFs) such as Ena/VASP, formins, and WASP-family proteins recruit profilin:actin for filament formation. Some of these are found to be microtubule associated, making actin polymerization from microtubule-associated platforms possible. Microtubules are implicated in focal adhesion turnover, cell polarity establishment, and migration, illustrating the coupling between actin and microtubule systems. Here we demonstrate that profilin is functionally linked to microtubules with formins and point to formins as major mediators of this association. To reach this conclusion, we combined different fluorescence microscopy techniques, including superresolution microscopy, with siRNA modulation of profilin expression and drug treatments to interfere with actin dynamics. Our studies show that profilin dynamically associates with microtubules and this fraction of profilin contributes to balance actin assembly during homeostatic cell growth and affects micro-tubule dynamics. Hence profilin functions as a regulator of microtubule (+)-end turnover in addition to being an actin control element.

  5. Probing the actin-auxin oscillator

    PubMed Central

    2010-01-01

    The directional transport of the plant hormone auxin depends on transcellular gradients of auxin-efflux carriers that continuously cycle between plasma membrane and intracellular compartments. This cycling has been proposed to depend on actin filaments. However, the role of actin for the polarity of auxin transport has been disputed. To get insight into this question, actin bundling was induced by overexpression of the actin-binding domain of talin in tobacco BY-2 cells and in rice plants. This bundling can be reverted by addition of auxins, which allows to address the role of actin organization on the flux of auxin. In both systems, the reversion of a normal actin configuration can be restored by addition of exogenous auxins and this fully restores the respective auxin-dependent functions. These findings lead to a model of a self-referring regulatory circuit between polar auxin transport and actin organization. To further dissect the actin-auxin oscillator, we used photoactivated release of caged auxin in tobacco cells to demonstrate that auxin gradients can be manipulated at a subcellular level. PMID:20023411

  6. Profilin connects actin assembly with microtubule dynamics

    PubMed Central

    Nejedla, Michaela; Sadi, Sara; Sulimenko, Vadym; de Almeida, Francisca Nunes; Blom, Hans; Draber, Pavel; Aspenström, Pontus; Karlsson, Roger

    2016-01-01

    Profilin controls actin nucleation and assembly processes in eukaryotic cells. Actin nucleation and elongation promoting factors (NEPFs) such as Ena/VASP, formins, and WASP-family proteins recruit profilin:actin for filament formation. Some of these are found to be microtubule associated, making actin polymerization from microtubule-associated platforms possible. Microtubules are implicated in focal adhesion turnover, cell polarity establishment, and migration, illustrating the coupling between actin and microtubule systems. Here we demonstrate that profilin is functionally linked to microtubules with formins and point to formins as major mediators of this association. To reach this conclusion, we combined different fluorescence microscopy techniques, including superresolution microscopy, with siRNA modulation of profilin expression and drug treatments to interfere with actin dynamics. Our studies show that profilin dynamically associates with microtubules and this fraction of profilin contributes to balance actin assembly during homeostatic cell growth and affects micro­tubule dynamics. Hence profilin functions as a regulator of microtubule (+)-end turnover in addition to being an actin control element. PMID:27307590

  7. Actin cytoskeleton redox proteome oxidation by cadmium

    PubMed Central

    Go, Young-Mi; Orr, Michael

    2013-01-01

    Epidemiological studies associate environmental cadmium (Cd) exposure with the risk of lung diseases. Although mechanisms are not fully elucidated, several studies demonstrate Cd effects on actin and actin-associated proteins. In a recent study of Cd at concentrations similar to environmental exposures, we found that redox-dependent inflammatory signaling by NF-κB was sensitive to the actin-disrupting agent, cytochalasin D. The goal of the present study was to use mass spectrometry-based redox proteomics to investigate Cd effects on the actin cytoskeleton proteome and related functional pathways in lung cells at low environmental concentrations. The results showed that Cd under conditions that did not alter total protein thiols or glutathione redox state caused significant oxidation of peptidyl Cys of proteins regulating actin cytoskeleton. Immunofluorescence microscopy of lung fibroblasts and pulmonary artery endothelial cells showed that low-dose Cd exposure stimulated filamentous actin formation and nuclear localization of destrin, an actin-depolymerizing factor. Taken together, the results show that redox states of peptidyl Cys in proteins associated with actin cytoskeleton pathways are selectively oxidized in lung by Cd at levels thought to occur from environmental exposure. PMID:24077948

  8. Colchicine activates actin polymerization by microtubule depolymerization.

    PubMed

    Jung, H I; Shin, I; Park, Y M; Kang, K W; Ha, K S

    1997-06-30

    Swiss 3T3 fibroblasts were treated with the microtubule-disrupting agent colchicine to study any interaction between microtubule dynamics and actin polymerization. Colchicine increased the amount of filamentous actin (F-actin), in a dose- and time-dependent manner with a significant increase at 1 h by about 130% over control level. Confocal microscopic observation showed that colchicine increased F-actin contents by stress fiber formation without inducing membrane ruffling. Colchicine did not activate phospholipase C and phospholipase D, whereas lysophosphatidic acid did, indicating that colchicine may have a different mechanism of actin polymerization regulation from LPA. A variety of microtubule-disrupting agents stimulated actin polymerization in Swiss 3T3 and Rat-2 fibroblasts as did colchicine, but the microtubule-stabilizing agent taxol inhibited actin polymerization induced by the above microtubule-disrupting agents. In addition, colchicine-induced actin polymerization was blocked by two protein phosphatase inhibitors, okadaic acid and calyculin A. These results suggest that microtubule depolymerization activates stress fiber formation by serine/threonine dephosphorylation in fibroblasts. PMID:9264034

  9. 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…

  10. Formin DAAM1 Organizes Actin Filaments in the Cytoplasmic Nodal Actin Network

    PubMed Central

    Luo, Weiwei; Lieu, Zi Zhao; Manser, Ed; Bershadsky, Alexander D.; Sheetz, Michael P.

    2016-01-01

    A nodal cytoplasmic actin network underlies actin cytoplasm cohesion in the absence of stress fibers. We previously described such a network that forms upon Latrunculin A (LatA) treatment, in which formin DAAM1 was localized at these nodes. Knock down of DAAM1 reduced the mobility of actin nodes but the nodes remained. Here we have investigated DAAM1 containing nodes after LatA washout. DAAM1 was found to be distributed between the cytoplasm and the plasma membrane. The membrane binding likely occurs through an interaction with lipid rafts, but is not required for F-actin assembly. Interesting the forced interaction of DAAM1 with plasma membrane through a rapamycin-dependent linkage, enhanced F-actin assembly at the cell membrane (compared to the cytoplasm) after the LatA washout. However, immediately after addition of both rapamycin and LatA, the cytoplasmic actin nodes formed transiently, before DAAM1 moved to the membrane. This was consistent with the idea that DAAM1 was initially anchored to cytoplasmic actin nodes. Further, photoactivatable tracking of DAAM1 showed DAAM1 was immobilized at these actin nodes. Thus, we suggest that DAAM1 organizes actin filaments into a nodal complex, and such nodal complexes seed actin network recovery after actin depolymerization. PMID:27760153

  11. Actin-binding proteins: the long road to understanding the dynamic landscape of cellular actin networks.

    PubMed

    Lappalainen, Pekka

    2016-08-15

    The actin cytoskeleton supports a vast number of cellular processes in nonmuscle cells. It is well established that the organization and dynamics of the actin cytoskeleton are controlled by a large array of actin-binding proteins. However, it was only 40 years ago that the first nonmuscle actin-binding protein, filamin, was identified and characterized. Filamin was shown to bind and cross-link actin filaments into higher-order structures and contribute to phagocytosis in macrophages. Subsequently many other nonmuscle actin-binding proteins were identified and characterized. These proteins regulate almost all steps of the actin filament assembly and disassembly cycles, as well as the arrangement of actin filaments into diverse three-dimensional structures. Although the individual biochemical activities of most actin-regulatory proteins are relatively well understood, knowledge of how these proteins function together in a common cytoplasm to control actin dynamics and architecture is only beginning to emerge. Furthermore, understanding how signaling pathways and mechanical cues control the activities of various actin-binding proteins in different cellular, developmental, and pathological processes will keep researchers busy for decades. PMID:27528696

  12. Integration of linear and dendritic actin nucleation in Nck-induced actin comets

    PubMed Central

    Borinskaya, Sofya; Velle, Katrina B.; Campellone, Kenneth G.; Talman, Arthur; Alvarez, Diego; Agaisse, Hervé; Wu, Yi I.; Loew, Leslie M.; Mayer, Bruce J.

    2016-01-01

    The Nck adaptor protein recruits cytosolic effectors such as N-WASP that induce localized actin polymerization. Experimental aggregation of Nck SH3 domains at the membrane induces actin comet tails—dynamic, elongated filamentous actin structures similar to those that drive the movement of microbial pathogens such as vaccinia virus. Here we show that experimental manipulation of the balance between unbranched/branched nucleation altered the morphology and dynamics of Nck-induced actin comets. Inhibition of linear, formin-based nucleation with the small-molecule inhibitor SMIFH2 or overexpression of the formin FH1 domain resulted in formation of predominantly circular-shaped actin structures with low mobility (actin blobs). These results indicate that formin-based linear actin polymerization is critical for the formation and maintenance of Nck-dependent actin comet tails. Consistent with this, aggregation of an exclusively branched nucleation-promoting factor (the VCA domain of N-WASP), with density and turnover similar to those of N-WASP in Nck comets, did not reconstitute dynamic, elongated actin comets. Furthermore, enhancement of branched Arp2/3-mediated nucleation by N-WASP overexpression caused loss of the typical actin comet tail shape induced by Nck aggregation. Thus the ratio of linear to dendritic nucleation activity may serve to distinguish the properties of actin structures induced by various viral and bacterial pathogens. PMID:26609071

  13. Integration of linear and dendritic actin nucleation in Nck-induced actin comets.

    PubMed

    Borinskaya, Sofya; Velle, Katrina B; Campellone, Kenneth G; Talman, Arthur; Alvarez, Diego; Agaisse, Hervé; Wu, Yi I; Loew, Leslie M; Mayer, Bruce J

    2016-01-15

    The Nck adaptor protein recruits cytosolic effectors such as N-WASP that induce localized actin polymerization. Experimental aggregation of Nck SH3 domains at the membrane induces actin comet tails--dynamic, elongated filamentous actin structures similar to those that drive the movement of microbial pathogens such as vaccinia virus. Here we show that experimental manipulation of the balance between unbranched/branched nucleation altered the morphology and dynamics of Nck-induced actin comets. Inhibition of linear, formin-based nucleation with the small-molecule inhibitor SMIFH2 or overexpression of the formin FH1 domain resulted in formation of predominantly circular-shaped actin structures with low mobility (actin blobs). These results indicate that formin-based linear actin polymerization is critical for the formation and maintenance of Nck-dependent actin comet tails. Consistent with this, aggregation of an exclusively branched nucleation-promoting factor (the VCA domain of N-WASP), with density and turnover similar to those of N-WASP in Nck comets, did not reconstitute dynamic, elongated actin comets. Furthermore, enhancement of branched Arp2/3-mediated nucleation by N-WASP overexpression caused loss of the typical actin comet tail shape induced by Nck aggregation. Thus the ratio of linear to dendritic nucleation activity may serve to distinguish the properties of actin structures induced by various viral and bacterial pathogens. PMID:26609071

  14. Xenopus egg cytoplasm with intact actin.

    PubMed

    Field, Christine M; Nguyen, Phuong A; Ishihara, Keisuke; Groen, Aaron C; Mitchison, Timothy J

    2014-01-01

    We report optimized methods for preparing Xenopus egg extracts without cytochalasin D, that we term "actin-intact egg extract." These are undiluted egg cytoplasm that contains abundant organelles, and glycogen which supplies energy, and represents the least perturbed cell-free cytoplasm preparation we know of. We used this system to probe cell cycle regulation of actin and myosin-II dynamics (Field et al., 2011), and to reconstitute the large, interphase asters that organize early Xenopus embryos (Mitchison et al., 2012; Wühr, Tan, Parker, Detrich, & Mitchison, 2010). Actin-intact Xenopus egg extracts are useful for analysis of actin dynamics, and interaction of actin with other cytoplasmic systems, in a cell-free system that closely mimics egg physiology, and more generally for probing the biochemistry and biophysics of the egg, zygote, and early embryo. Detailed protocols are provided along with assays used to check cell cycle state and tips for handling and storing undiluted egg extracts.

  15. Crystal structure of an archaeal actin homolog.

    PubMed

    Roeben, Annette; Kofler, Christine; Nagy, István; Nickell, Stephan; Hartl, F Ulrich; Bracher, Andreas

    2006-04-21

    Prokaryotic homologs of the eukaryotic structural protein actin, such as MreB and ParM, have been implicated in determination of bacterial cell shape, and in the segregation of genomic and plasmid DNA. In contrast to these bacterial actin homologs, little is known about the archaeal counterparts. As a first step, we expressed a predicted actin homolog of the thermophilic archaeon Thermoplasma acidophilum, Ta0583, and determined its crystal structure at 2.1A resolution. Ta0583 is expressed as a soluble protein in T.acidophilum and is an active ATPase at physiological temperature. In vitro, Ta0583 forms sheets with spacings resembling the crystal lattice, indicating an inherent propensity to form filamentous structures. The fold of Ta0583 contains the core structure of actin and clearly belongs to the actin/Hsp70 superfamily of ATPases. Ta0583 is approximately equidistant from actin and MreB on the structural level, and combines features from both eubacterial actin homologs, MreB and ParM. The structure of Ta0583 co-crystallized with ADP indicates that the nucleotide binds at the interface between the subdomains of Ta0583 in a manner similar to that of actin. However, the conformation of the nucleotide observed in complex with Ta0583 clearly differs from that in complex with actin, but closely resembles the conformation of ParM-bound nucleotide. On the basis of sequence and structural homology, we suggest that Ta0583 derives from a ParM-like actin homolog that was once encoded by a plasmid and was transferred into a common ancestor of Thermoplasma and Ferroplasma. Intriguingly, both genera are characterized by the lack of a cell wall, and therefore Ta0583 could have a function in cellular organization.

  16. Probing actin incorporation into myofibrils using Asp11 and His73 actin mutants.

    PubMed

    Xia, D; Peng, B; Sesok, D A; Peng, I

    1993-01-01

    We used a cell free system Bouché et al.: J. Cell Biol. 107:587-596, 1988] to study the incorporation of actin into myofibrils. We used alpha-skeletal muscle actin and actins with substitutions of either His73 [Solomon and Rubenstein: J. Biol.Chem. 262:11382, 1987], or Asp11 [Solomon et al.: J. Biol. Chem. 263:19662, 1988]. Actins were translated in reticulocyte lysate and incubated with myofibrils. The incorporated wild type actin could be cross-linked into dimers using N,N'-1,4-phenylenebismaleimide (PBM), indicating that the incorporated actin is actually inserted into the thin filaments of the myofibril. The His73 mutants incorporated to the same extent as wild type actin and was also cross-linked with PBM. Although some of the Asp11 mutants co-assembled with carrier actin, only 1-3% of the Asp11 mutant actins incorporated after 2 min and did not increase after 2 hr. Roughly 17% of wild type actin incorporated after 2 min and 31% after 2 hr. ATP increased the release of wild type actin from myofibrils, but did not increase the release of Asp11 mutants. We suggest that (1) the incorporation of wild type and His73 mutant actins was due to a physiological process whereas association of Asp11 mutants with myofibrils was non-specific, (2) the incorporation of wild type actin involved a rapid initial phase, followed by a slower phase, and (3) since some of the Asp11 mutants can co-assemble with wild type actin, the ability to self-assemble was not sufficient for incorporation into myofibrils. Thus, incorporation probably includes interaction between actin and a thin filament associated protein. We also showed that incorporation occurred at actin concentrations which would cause disassembly of F-actin. Since the myofibrils did not show large scale disassembly but incorporated actin, filament stability and monomer incorporation are likely to be mediated by actin associated proteins of the myofibril. PMID:8287497

  17. Inspection of imprint lithography patterns for semiconductor and patterned media

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  18. Dynamics of an actin spring

    NASA Astrophysics Data System (ADS)

    Riera, Christophe; Mahadevan, L.; Shin, Jennifer; Matsudaira, Paul

    2003-03-01

    The acrosome of the sperm of the horseshoe crab (Limulus Polyphemus) is an unusual actin based system that shows a spectacular dynamical transition in the presence of Ca++ that is present in abundance in the neighborhood of the egg. During this process, the bundle, which is initially bent and twisted uncoils and becomes straight in a matter of a few seconds. Based on microstructural data, we propose a model for the dynamics of uncoiling that is best represented by a triple-well potential corresponding to the different structural arrangements of the supertwisted filaments. Each of the false, true and coiled states corresponds to a local minimum of the energy, with the true state being the one with the lowest energy. Using an evolution equation derived by balancing torques, we investigate the nucleation and propagation of the phase transition and compare the results with those of experiments. Our model quantifies the hypothesis that the acrosomal bundle behaves like a mechano-chemical spring.

  19. Improving vision by pupil masking.

    PubMed

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

    2016-07-01

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

  20. Improving vision by pupil masking

    PubMed Central

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

    2016-01-01

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

  1. Variations in programmed phase defect size and its impact on defect detection signal intensity using at-wavelength inspection system

    NASA Astrophysics Data System (ADS)

    Amano, Tsuyoshi; Takagi, Noriaki; Abe, Tsukasa

    2015-10-01

    A programmed phase defect Extreme Ultraviolet (EUV) mask was fabricated and measurement repeatability of the defect size using a scanning probe microscope (SPM) was evaluated. The SPM measurement results indicated that the defect size variation as registered by the measurement repeatability were much smaller than the defect-to-defect variations. It means the defect-to-defect variation in size actually does exist. Some defects were found where their sizes before a multilayer coating (on quartz) were all the same but after the coat their sizes varied quite significantly when observed on the multilayer. This result indicated that it is difficult to estimate the phase defect size on quartz, whereas they can be accurately measured on multilayer. Influences of the defect size variation on defect detection signal intensity (DSI) using an actinic blank inspection (ABI) system were examined; their influences on the wafer printability were also examined. The DSI was strongly correlated with defect depth on the multilayer, and it was also indicated that the ABI can detect small variations in defect sizes. It was also confirmed that the impact of the phase defects on wafer printed CDs were proportional to the DSIs, and that the ABI has a potential to detect phase defect that could cause 5 % of the CD error when printing 16 nm dense lines.

  2. History and future of mask making

    NASA Astrophysics Data System (ADS)

    Levy, Ken L.

    1996-12-01

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

  3. Cortical correlate of pattern backward masking.

    PubMed Central

    Kovács, G; Vogels, R; Orban, G A

    1995-01-01

    The perception of a briefly presented shape is strongly impaired when it is followed by another pattern, a phenomenon called backward masking. We found that the vast majority of a sample of shape-selective neurons in the macaque inferior temporal cortex respond selectively to backward-masked shapes, although these shapes could not be discriminated by human and monkey subjects. However, this selective response was brief, since it was either interrupted by the mask or overridden by a response to the mask itself. We show that reliable discrimination of briefly presented shapes by single neurons depends on the temporal integration of the response. Presentation of the mask, however, reduces the number of spikes available for integration, explaining backward masking. These results also provide direct neurophysiological evidence for the "interruption theory" of backward masking. PMID:7777553

  4. Actin depolymerizing factor controls actin turnover and gliding motility in Toxoplasma gondii

    PubMed Central

    Mehta, Simren; Sibley, L. David

    2011-01-01

    Apicomplexan parasites rely on actin-based gliding motility to move across the substratum, cross biological barriers, and invade their host cells. Gliding motility depends on polymerization of parasite actin filaments, yet ∼98% of actin is nonfilamentous in resting parasites. Previous studies suggest that the lack of actin filaments in the parasite is due to inherent instability, leaving uncertain the role of actin-binding proteins in controlling dynamics. We have previously shown that the single allele of Toxoplasma gondii actin depolymerizing factor (TgADF) has strong actin monomer–sequestering and weak filament-severing activities in vitro. Here we used a conditional knockout strategy to investigate the role of TgADF in vivo. Suppression of TgADF led to accumulation of actin-rich filaments that were detected by immunofluorescence and electron microscopy. Parasites deficient in TgADF showed reduced speed of motility, increased aberrant patterns of motion, and inhibition of sustained helical gliding. Lack of TgADF also led to severe defects in entry and egress from host cells, thus blocking infection in vitro. These studies establish that the absence of stable actin structures in the parasite are not simply the result of intrinsic instability, but that TgADF is required for the rapid turnover of parasite actin filaments, gliding motility, and cell invasion. PMID:21346192

  5. Reversible stress softening of actin networks

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Ovijit; Parekh, Sapun H.; Fletcher, Daniel A.

    2007-01-01

    The mechanical properties of cells play an essential role in numerous physiological processes. Organized networks of semiflexible actin filaments determine cell stiffness and transmit force during mechanotransduction, cytokinesis, cell motility and other cellular shape changes. Although numerous actin-binding proteins have been identified that organize networks, the mechanical properties of actin networks with physiological architectures and concentrations have been difficult to measure quantitatively. Studies of mechanical properties in vitro have found that crosslinked networks of actin filaments formed in solution exhibit stress stiffening arising from the entropic elasticity of individual filaments or crosslinkers resisting extension. Here we report reversible stress-softening behaviour in actin networks reconstituted in vitro that suggests a critical role for filaments resisting compression. Using a modified atomic force microscope to probe dendritic actin networks (like those formed in the lamellipodia of motile cells), we observe stress stiffening followed by a regime of reversible stress softening at higher loads. This softening behaviour can be explained by elastic buckling of individual filaments under compression that avoids catastrophic fracture of the network. The observation of both stress stiffening and softening suggests a complex interplay between entropic and enthalpic elasticity in determining the mechanical properties of actin networks.

  6. Comparative Study of Manufacturing Techniques for Coronagraphic Binary Pupil Masks: Masks on Substrates and Free-Standing Masks

    NASA Astrophysics Data System (ADS)

    Enya, Keigo; Haze, Kanae; Kotani, Takayuki; Abe, Lyu

    2012-12-01

    We present a comparative study of the manufacture of binary pupil masks for coronagraphic observations of exoplanets. A checkerboard mask design, a type of binary pupil mask design, was adopted, and identical patterns of the same size were used for all masks in order that we could compare the differences resulting from the different manufacturing methods. The masks on substrates had aluminum checkerboard patterns with thicknesses of 0.1/0.2/0.4/0.8/1.6μm, constructed on substrates of BK7 glass, silicon, and germanium using photolithography and chemical processes. Free-standing masks made of copper and nickel with thicknesses of 2/5/10/20μm were also realized using photolithography and chemical processes, which included careful release from the substrate used as an intermediate step in the manufacture. Coronagraphic experiments using a visible laser were carried out for all masks on BK7 glass substrate and the free-standing masks. The average contrasts were 8.4 × 10-8, 1.2 × 10-7, and 1.2 × 10-7 for the masks on BK7 substrates, the free-standing copper masks, and the free-standing nickel masks, respectively. No significant correlation was concluded between the contrast and the mask properties. The high-contrast masks have the potential to cover the needs of coronagraphs for both ground-based and space-borne telescopes over a wide wavelength range. Especially, their application to the infrared space telescope, SPICA, is appropriate.

  7. Actinic Granuloma with Focal Segmental Glomerulosclerosis

    PubMed Central

    Phasukthaworn, Ruedee; Chanprapaph, Kumutnart; Vachiramon, Vasanop

    2016-01-01

    Actinic granuloma is an uncommon granulomatous disease, characterized by annular erythematous plaque with central clearing predominately located on sun-damaged skin. The pathogenesis is not well understood, ultraviolet radiation is recognized as precipitating factor. We report a case of a 52-year-old woman who presented with asymptomatic annular erythematous plaques on the forehead and both cheeks persisting for 2 years. The clinical presentation and histopathologic findings support the diagnosis of actinic granuloma. During that period of time, she also developed focal segmental glomerulosclerosis. The association between actinic granuloma and focal segmental glomerulosclerosis needs to be clarified by further studies. PMID:27293392

  8. Binding of actin to lens alpha crystallins

    NASA Technical Reports Server (NTRS)

    Gopalakrishnan, S.; Takemoto, L.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    Actin has been coupled to a cyanogen bromide-activated Sepharose 4B column, then tested for binding to alpha, beta, and gamma crystallin preparations from the bovine lens. Alpha, but not beta or gamma, crystallins bound to the actin affinity column in a time dependent and saturable manner. Subfractionation of the alpha crystallin preparation into the alpha-A and alpha-B species, followed by incubation with the affinity column, demonstrated that both species bound approximately the same. Together, these studies demonstrate a specific and saturable binding of lens alpha-A and alpha-B with actin.

  9. Dynamic reorganization of the actin cytoskeleton

    PubMed Central

    Gressin, Laurène; Théry, Manuel; Blanchoin, Laurent

    2015-01-01

    Cellular processes, including morphogenesis, polarization, and motility, rely on a variety of actin-based structures. Although the biochemical composition and filament organization of these structures are different, they often emerge from a common origin. This is possible because the actin structures are highly dynamic. Indeed, they assemble, grow, and disassemble in a time scale of a second to a minute. Therefore, the reorganization of a given actin structure can promote the formation of another. Here, we discuss such transitions and illustrate them with computer simulations. PMID:26989473

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

  11. Computational model of polarized actin cables and cytokinetic actin ring formation in budding yeast

    PubMed Central

    Tang, Haosu; Bidone, Tamara C.

    2015-01-01

    The budding yeast actin cables and contractile ring are important for polarized growth and division, revealing basic aspects of cytoskeletal function. To study these formin-nucleated structures, we built a 3D computational model with actin filaments represented as beads connected by springs. Polymerization by formins at the bud tip and bud neck, crosslinking, severing, and myosin pulling, are included. Parameter values were estimated from prior experiments. The model generates actin cable structures and dynamics similar to those of wild type and formin deletion mutant cells. Simulations with increased polymerization rate result in long, wavy cables. Simulated pulling by type V myosin stretches actin cables. Increasing the affinity of actin filaments for the bud neck together with reduced myosin V pulling promotes the formation of a bundle of antiparallel filaments at the bud neck, which we suggest as a model for the assembly of actin filaments to the contractile ring. PMID:26538307

  12. Correlation between polymerizability and conformation in scallop beta-like actin and rabbit skeletal muscle alpha-actin.

    PubMed

    Khaitlina, S; Antropova, O; Kuznetsova, I; Turoverov, K; Collins, J H

    1999-08-01

    In order to investigate the structural basis for functional differences among actin isoforms, we have compared the polymerization properties and conformations of scallop adductor muscle beta-like actin and rabbit skeletal muscle alpha-actin. Polymerization of scallop Ca(2+)-actin was slower than that of skeletal muscle Ca(2+)-actin. Cleavage of the actin polypeptide chain between Gly-42 and Val-43 with Escherichia coli protease ECP 32 impaired the polymerization of scallop Mg(2+)-actin to a greater extent than skeletal muscle Mg(2+)-actin. When monomeric scallop and skeletal muscle Ca(2+)-actins were subjected to limited proteolysis with trypsin, subtilisin, or ECP 32, no differences in the conformation of actin subdomain 2 were detected. At the same time, local differences in the conformations of scallop and skeletal muscle actin subdomains 1 were revealed as intrinsic fluorescence differences. Replacement of tightly bound Ca(2+) with Mg(2+) resulted in more extensive proteolysis of segment 61-69 of scallop actin than in the case of skeletal muscle actin. Furthermore, segment 61-69 was more accessible to proteolysis with subtilisin in polymerized scallop Ca(2+)-actin than in polymerized skeletal muscle Ca(2+)-actin, indicating that, in the polymeric form, the nucleotide-containing cleft is in a more open conformation in beta-like scallop actin than in skeletal muscle alpha-actin. We suggest that this difference between scallop and skeletal muscle actins is due to a less efficient shift of scallop actin subdomain 2 to the position it has in the polymer. The possible consequences of amino acid substitutions in actin subdomain 1 in the allosteric regulation of the actin cleft, and hence in the different stabilities of polymers formed by different actins, are discussed. PMID:10415117

  13. Structural Differences Explain Diverse Functions of Plasmodium Actins

    PubMed Central

    Vahokoski, Juha; Martinez, Silvia Muñico; Ignatev, Alexander; Lepper, Simone; Frischknecht, Friedrich; Sidén-Kiamos, Inga; Sachse, Carsten; Kursula, Inari

    2014-01-01

    Actins are highly conserved proteins and key players in central processes in all eukaryotic cells. The two actins of the malaria parasite are among the most divergent eukaryotic actins and also differ from each other more than isoforms in any other species. Microfilaments have not been directly observed in Plasmodium and are presumed to be short and highly dynamic. We show that actin I cannot complement actin II in male gametogenesis, suggesting critical structural differences. Cryo-EM reveals that Plasmodium actin I has a unique filament structure, whereas actin II filaments resemble canonical F-actin. Both Plasmodium actins hydrolyze ATP more efficiently than α-actin, and unlike any other actin, both parasite actins rapidly form short oligomers induced by ADP. Crystal structures of both isoforms pinpoint several structural changes in the monomers causing the unique polymerization properties. Inserting the canonical D-loop to Plasmodium actin I leads to the formation of long filaments in vitro. In vivo, this chimera restores gametogenesis in parasites lacking actin II, suggesting that stable filaments are required for exflagellation. Together, these data underline the divergence of eukaryotic actins and demonstrate how structural differences in the monomers translate into filaments with different properties, implying that even eukaryotic actins have faced different evolutionary pressures and followed different paths for developing their polymerization properties. PMID:24743229

  14. Actin filament organization of foot processes in vertebrate glomerular podocytes.

    PubMed

    Ichimura, Koichiro; Kurihara, Hidetake; Sakai, Tatsuo

    2007-09-01

    We investigated the actin filament organization and immunolocalization of actin-binding proteins (alpha-actinin and cortactin) in the podocyte foot processes of eight vertebrate species (lamprey, carp, newt, frog, gecko, turtle, quail, and rat). Three types of actin cytoskeleton were found in these foot processes. (1) A cortical actin network with cortactin filling the space between the plasma membrane and the other actin cytoskeletons described below was found in all of the species examined here. The data indicated that the cortical actin network was the minimal essential actin cytoskeleton for the formation and maintenance of the foot processes in vertebrate podocytes. (2) An actin bundle with alpha-actinin existing along the longitudinal axis of foot process above the level of slit diaphragms was only observed in quail and rat. (3) An actin fascicle consisting of much fewer numbers of actin filaments than that of the actin bundle was observed in the species other than quail and rat, but at various frequencies. These findings suggest that the actin bundle is an additional actin cytoskeleton reflecting a functional state peculiar to quail and rat glomeruli. Considering the higher intraglomerular pressure and the extremely thin filtration barrier in birds and mammals, the foot processes probably mainly protect the thinner filtration barrier from the higher internal pressure occurring in quail and rat glomeruli. Therefore, we consider that the actin bundle plays a crucial role in the mechanical protection of the filtration barrier. Moreover, the actin fascicle may be a potential precursor of the actin bundle.

  15. Genetics Home Reference: actin-accumulation myopathy

    MedlinePlus

    ... 7(3):160-8. Citation on PubMed Laing NG, Dye DE, Wallgren-Pettersson C, Richard G, Monnier ... Vigneron J, Wallgren-Pettersson C, Beggs AH, Laing NG. Mutations in the skeletal muscle alpha-actin gene ...

  16. [Actin in the wound healing process].

    PubMed

    Nowak, Dorota; Popow-Woźniak, Agnieszka; Raźnikiewicz, Linda; Malicka-Błaszkiewicz, Maria

    2009-01-01

    Wound healing is an important biological process of crucial value for organisms survival and retention of its proper functions. The recognition of molecular mechanisms of these phenomenon is still under investigation. The transition of mesenchymal fibroblasts to myofibroblasts is a key point in wound healing. The contraction ability of myofibroblast enables the shrinkage of a wound and closes its edges. Alpha smooth muscle actin (alpha-SMA), one of six actin isoforms, is a marker of compeletely differentiated myofibroblast. The regulation of differentiation process depends on many growth factors (especially TGF beta 1), the level of active thymosin beta 4, extracellular matrix proteins--including fibronectin, and also on specificity of microenvironment. Thymosin beta 4 is responsible for maintenance of pool of monomeric actin and actin filaments depolymerization. It can also act as a transcription factor, migration stimulator and immunomodulator, so this protein deserves for more attention in wound healing research field. PMID:19824469

  17. Structural Dynamics of an Actin Spring

    PubMed Central

    Mahadevan, L.; Riera, C.S.; Shin, Jennifer H.

    2011-01-01

    Actin-based motility in cells is usually associated with either polymerization/depolymerization in the presence of cross-linkers or contractility in the presence of myosin motors. Here, we focus on a third distinct mechanism involving actin in motility, seen in the dynamics of an active actin spring that powers the acrosomal reaction of the horseshoe crab (Limulus polyphemus) sperm. During this process, a 60-μm bent and twisted bundle of cross-linked actin uncoils and becomes straight in a few seconds in the presence of Ca2+. This straightening, which occurs at a constant velocity, allows the acrosome to forcefully penetrate the egg. Synthesizing ultrastructural information with the kinetics, energetics, and imaging of calcium binding allows us to construct a dynamical theory for this mechanochemical engine consistent with our experimental observations. It also illuminates the general mechanism by which energy may be stored in conformational changes and released cooperatively in ordered macromolecular assemblies. PMID:21320427

  18. Mechanics model for actin-based motility.

    PubMed

    Lin, Yuan

    2009-02-01

    We present here a mechanics model for the force generation by actin polymerization. The possible adhesions between the actin filaments and the load surface, as well as the nucleation and capping of filament tips, are included in this model on top of the well-known elastic Brownian ratchet formulation. A closed form solution is provided from which the force-velocity relationship, summarizing the mechanics of polymerization, can be drawn. Model predictions on the velocity of moving beads driven by actin polymerization are consistent with experiment observations. This model also seems capable of explaining the enhanced actin-based motility of Listeria monocytogenes and beads by the presence of Vasodilator-stimulated phosphoprotein, as observed in recent experiments.

  19. Mechanics model for actin-based motility

    NASA Astrophysics Data System (ADS)

    Lin, Yuan

    2009-02-01

    We present here a mechanics model for the force generation by actin polymerization. The possible adhesions between the actin filaments and the load surface, as well as the nucleation and capping of filament tips, are included in this model on top of the well-known elastic Brownian ratchet formulation. A closed form solution is provided from which the force-velocity relationship, summarizing the mechanics of polymerization, can be drawn. Model predictions on the velocity of moving beads driven by actin polymerization are consistent with experiment observations. This model also seems capable of explaining the enhanced actin-based motility of Listeria monocytogenes and beads by the presence of Vasodilator-stimulated phosphoprotein, as observed in recent experiments.

  20. Nematic textures in F-actin

    NASA Astrophysics Data System (ADS)

    Das, P.; Roy, J.; Chakrabarti, N.; Basu, S.; Das, U.

    2002-05-01

    Actin filaments, which are protein polymers occurring abundantly and ubiquitously in muscle and nonmuscle cells, are known to align in a shear flow, and with an external magnetic field. They form a nematic liquid crystal of the athermal type at a low concentration. Typical defects and textures of the nematic actin liquid crystal are described in this work. The generation of well-aligned nematic single crystals has been reported, in the vicinity of an air-water interface, with the actin filaments spontaneously aligning normal to the interface. Away from the air-water interface nematic single crystal domains are due to the alignment of the actin filaments parallel to the glass surface. The twist-bend nature of the disclination line of integral strength (m=1) has been attributed to the relative magnitudes of the anisotropic curvature elastic constants, which reflect the filaments' semirigidity.

  1. Elasticity of F-actin networks

    NASA Astrophysics Data System (ADS)

    Gardel, Margaret Lise

    This thesis presents a study of the elasticity and microstructure of three filamentous actin (F-actin) based materials. Using bulk rheology, microrheology, multiple particle tracking and imaging techniques, we study the microscopic origins of the mechanical properties of F-actin networks. We briefly introduce aspects of F-actin and rheology essential to provide a background for and motivate this thesis in Chapter 1. In Chapter 2, we describe the materials and methods used. An introduction to microrheology is given in Chapter 3. In Chapter 4, we study solutions of entangled F-actin. We elucidate the microscopic origins of bulk elasticity using microrheology techniques. We also show that multiple particle tracking can also probe the dynamics of the F-actin solution microstructure. We explore the effect of rigid, incompliant chemical cross-links between actin filaments in Chapter 5. We explore changes in the network microstructure as the concentration of cross-links is varied. We find that the elastic stiffness of these networks is extremely sensitive to small changes in cross-link density. Despite this large variation, the linear viscoelasticity of all networks can be scaled onto a universal master curve; this scaling reveals that the mechanical dissipation of the networks is due to thermal fluctuations of F-actin. At large stresses, the mechanical stiffness of these networks diverges. The form of this stress stiffening response is consistent with the non-linear force extension of a single semi-flexible polymer. Thus, over a large range of conditions, the linear and nonlinear mechanical response of rigidly cross-linked networks is entropic in origin. Finally, at very low cross-link and filament densities, we observe a transition to a qualitatively different type of elasticity; this is consistent with a transition to an enthalpic network elasticity dominated by bending of F-actin. In Chapter 6, we study the elastic properties of F-actin networks assembled with a

  2. High-resolution defect inspection of step-and-flash imprint lithography for 32-nm half-pitch patterning

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; McMackin, Ian; Sreenivasan, S. V.; Resnick, Douglas J.

    2009-03-01

    Step and Flash Imprint involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using KLA-T eS35 and NGR2100 electron beam wafer inspection systems. Defect sizes as small as 8 nm were detected, and detection limits were found to be a function of defect type.

  3. Mechanism of Actin Filament Bundling by Fascin

    SciTech Connect

    Jansen, Silvia; Collins, Agnieszka; Yang, Changsong; Rebowski, Grzegorz; Svitkina, Tatyana; Dominguez, Roberto

    2013-03-07

    Fascin is the main actin filament bundling protein in filopodia. Because of the important role filopodia play in cell migration, fascin is emerging as a major target for cancer drug discovery. However, an understanding of the mechanism of bundle formation by fascin is critically lacking. Fascin consists of four {beta}-trefoil domains. Here, we show that fascin contains two major actin-binding sites, coinciding with regions of high sequence conservation in {beta}-trefoil domains 1 and 3. The site in {beta}-trefoil-1 is located near the binding site of the fascin inhibitor macroketone and comprises residue Ser-39, whose phosphorylation by protein kinase C down-regulates actin bundling and formation of filopodia. The site in {beta}-trefoil-3 is related by pseudo-2-fold symmetry to that in {beta}-trefoil-1. The two sites are {approx}5 nm apart, resulting in a distance between actin filaments in the bundle of {approx}8.1 nm. Residue mutations in both sites disrupt bundle formation in vitro as assessed by co-sedimentation with actin and electron microscopy and severely impair formation of filopodia in cells as determined by rescue experiments in fascin-depleted cells. Mutations of other areas of the fascin surface also affect actin bundling and formation of filopodia albeit to a lesser extent, suggesting that, in addition to the two major actin-binding sites, fascin makes secondary contacts with other filaments in the bundle. In a high resolution crystal structure of fascin, molecules of glycerol and polyethylene glycol are bound in pockets located within the two major actin-binding sites. These molecules could guide the rational design of new anticancer fascin inhibitors.

  4. Actin: its cumbersome pilgrimage through cellular compartments.

    PubMed

    Schleicher, Michael; Jockusch, Brigitte M

    2008-06-01

    In this article, we follow the history of one of the most abundant, most intensely studied proteins of the eukaryotic cells: actin. We report on hallmarks of its discovery, its structural and functional characterization and localization over time, and point to present days' knowledge on its position as a member of a large family. We focus on the rather puzzling number of diverse functions as proposed for actin as a dual compartment protein. Finally, we venture on some speculations as to its origin.

  5. Polarization masks: concept and initial assessment

    NASA Astrophysics Data System (ADS)

    Lam, Michael; Neureuther, Andrew R.

    2002-07-01

    Polarization from photomasks can be used as a new lever to improve lithographic performance in both binary and phase-shifting masks (PSMs). While PSMs manipulate the phase of light to control the temporal addition of electric field vectors, polarization masks manipulate the vector direction of electric field vectors to control the spatial addition of electric field components. This paper explores the theoretical possibilities of polarization masks, showing that it is possible to use bar structures within openings on the mask itself to polarize incident radiation. Rigorous electromagnetic scattering simulations using TEMPEST and imaging with SPLAT are used to give an initial assessment on the functionality of polarization masks, discussing the polarization quality and throughputs achieved with the masks. Openings between 1/8 and 1/3 of a wavelength provide both a low polarization ratio and good transmission. A final overall throughput of 33% - 40% is achievable, corresponding to a dose hit of 2.5x - 3x.

  6. Repairing native defects on EUV mask blanks

    NASA Astrophysics Data System (ADS)

    Lawliss, Mark; Gallagher, Emily; Hibbs, Michael; Seki, Kazunori; Isogawa, Takeshi; Robinson, Tod; LeClaire, Jeff

    2014-10-01

    Mask defectivity is a serious problem for all lithographic masks, but especially for EUV masks. Defects in the EUV blank are particularly challenging because their elimination is beyond control of the mask fab. If defects have been identified on a mask blank, patterns can be shifted to place as many blank defects as possible in regions where printing impact will be eliminated or become unimportant. For those defects that cannot be mitigated through pattern shift, repair strategies must be developed. Repairing defects that occur naturally in the EUV blank is challenging because the printability of these defects varies widely. This paper describes some types of native defects commonly found and begins to outline a triage strategy for defects that are identified on the blank. Sample defects best suited to nanomachining repair are treated in detail: repairs are attempted, characterized using mask metrology and then tested for printability. Based on the initial results, the viability of repairing EUV blank native defects is discussed.

  7. Semiconductor technology trend and requirements for masks

    NASA Astrophysics Data System (ADS)

    Komiya, Hiroyoshi

    1999-08-01

    The fabrication cost of the semiconductor device is increasing because the fabrication cost per wafer unit area and the mask cost are increasing rapidly with the design rule decreased. The rapid increase in the mask cost will influence the semiconductor industry growth. The progress in the lithography, including the mask, is the key issue for the progress in the entire semiconductor technology beyond 180 nm design rule, because the mask is indispensable for any types of lithography, and is regarded as one of the most critical technologies, both in resolution and productivity. To continue the progress in the entire semiconductor technology and the growth of the semiconductor business, it is indispensable to make challenges in the low cost and high precision mask technology under the cooperation with related industries and academia. It is especially important to develop the cost optimum solution for the total lithography technology including masks.

  8. Sarcomeric Pattern Formation by Actin Cluster Coalescence

    PubMed Central

    Friedrich, Benjamin M.; Fischer-Friedrich, Elisabeth; Gov, Nir S.; Safran, Samuel A.

    2012-01-01

    Contractile function of striated muscle cells depends crucially on the almost crystalline order of actin and myosin filaments in myofibrils, but the physical mechanisms that lead to myofibril assembly remains ill-defined. Passive diffusive sorting of actin filaments into sarcomeric order is kinetically impossible, suggesting a pivotal role of active processes in sarcomeric pattern formation. Using a one-dimensional computational model of an initially unstriated actin bundle, we show that actin filament treadmilling in the presence of processive plus-end crosslinking provides a simple and robust mechanism for the polarity sorting of actin filaments as well as for the correct localization of myosin filaments. We propose that the coalescence of crosslinked actin clusters could be key for sarcomeric pattern formation. In our simulations, sarcomere spacing is set by filament length prompting tight length control already at early stages of pattern formation. The proposed mechanism could be generic and apply both to premyofibrils and nascent myofibrils in developing muscle cells as well as possibly to striated stress-fibers in non-muscle cells. PMID:22685394

  9. Polyurethane Masks Large Areas in Electroplating

    NASA Technical Reports Server (NTRS)

    Beasley, J. L.

    1985-01-01

    Polyurethane foam provides effective mask in electroplating of copper or nickel. Thin layer of Turco maskant painted on area to be masked: Layer ensures polyurethane foam removed easily after served its purpose. Component A, isocyanate, and component B, polyol, mixed together and brushed or sprayed on mask area. Mixture reacts, yielding polyurethane foam. Foam prevents deposition of nickel or copper on covered area. New method saves time, increases productivity and uses less material than older procedures.

  10. VIIRS Cloud Mask Validation Exercises

    NASA Astrophysics Data System (ADS)

    Frey, R.; Heidinger, A. K.; Hutchison, K.; Dutcher, S.

    2011-12-01

    The NPP Satellite is scheduled for launch October 25, 2011. Included on the platform is the VIIRS (Visible/Infrared Imager/Suite) instrument which features 16 bands at about 0.75 m spatial resolution and 5 imager bands at roughly 0.375 m resolution. The basic VIIRS cloud mask (VCM) output is a flag that indicates one of four possible cloudy vs. clear conditions for each 0.75 m pixel: confident clear, probably clear, probably cloudy, and confident cloudy. Pre-launch assessment of the VCM algorithm has been performed with use of MODIS observations as proxy input. Several comparisons are shown between VCM results and cloud detection from other instruments and/or algorithms: MODIS cloud mask (MOD35) at the five-minute granule level (L2), global and regional monthly average cloud amounts from MODIS (MOD35) and MODIS-CERES, ISCCP, PATMOS-x (AVHRR), and CALIOP (lidar). In addition to overall results, collocated MODIS observations, CALIOP and VCM cloud determinations are used to evaluate VCM cloud test thresholds and other tunable parameters. The methods shown will be among those used during the Intensive Calibration and Validation period and beyond.

  11. X-ray lithography masking

    NASA Technical Reports Server (NTRS)

    Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

    1998-01-01

    X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

  12. Mask lithography for display manufacturing

    NASA Astrophysics Data System (ADS)

    Sandstrom, T.; Ekberg, P.

    2010-05-01

    The last ten years have seen flat displays conquer our briefcases, desktops, and living rooms. There has been an enormous development in production technology, not least in lithography and photomasks. Current masks for large displays are more than 2 m2 and make 4-6 1X prints on glass substrates that are 9 m2. One of the most challenging aspects of photomasks for displays is the so called mura, stripes or blemishes which cause visible defects in the finished display. For the future new and even tighter maskwriter specifications are driven by faster transistors and more complex pixel layouts made necessary by the market's wish for still better image quality, multi-touch panels, 3D TVs, and the next wave of e-book readers. Large OLED screens will pose new challenges. Many new types of displays will be lowcost and use simple lithography, but anything which can show video and high quality photographic images needs a transistor backplane and sophisticated masks for its production.

  13. Evaluation of a native vegetation masking technique

    NASA Technical Reports Server (NTRS)

    Kinsler, M. C.

    1984-01-01

    A crop masking technique based on Ashburn's vegetative index (AVI) was used to evaluate native vegetation as an indicator of crop moisture condition. A mask of the range areas (native vegetation) was generated for each of thirteen Great Plains LANDSAT MSS sample segments. These masks were compared to the digitized ground truth and accuracies were computed. An analysis of the types of errors indicates a consistency in errors among the segments. The mask represents a simple quick-look technique for evaluating vegetative cover.

  14. 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.

  15. Resemblance of actin-binding protein/actin gels to covalently crosslinked networks

    NASA Astrophysics Data System (ADS)

    Janmey, Paul A.; Hvidt, Søren; Lamb, Jennifer; Stossel, Thomas P.

    1990-05-01

    THE maintainance of the shape of cells is often due to their surface elasticity, which arises mainly from an actin-rich cytoplasmic cortex1,2. On locomotion, phagocytosis or fission, however, these cells become partially fluid-like. The finding of proteins that can bind to actin and control the assembly of, or crosslink, actin filaments, and of intracellular messages that regulate the activities of some of these actin-binding proteins, indicates that such 'gel sol' transformations result from the rearrangement of cortical actin-rich networks3. Alternatively, on the basis of a study of the mechanical properties of mixtures of actin filaments and an Acanthamoeba actin-binding protein, α-actinin, it has been proposed that these transformations can be accounted for by rapid exchange of crosslinks between actin filaments4: the cortical network would be solid when the deformation rate is greater than the rate of crosslink exchange, but would deform or 'creep' when deformation is slow enough to permit crosslinker molecules to rearrange. Here we report, however, that mixtures of actin filaments and actin-binding protein (ABP), an actin crosslinking protein of many higher eukaryotes, form gels Theologically equivalent to covalently crosslinked networks. These gels do not creep in response to applied stress on a time scale compatible with most cell-surface movements. These findings support a more complex and controlled mechanism underlying the dynamic mechanical properties of cortical cytoplasm, and can explain why cells do not collapse under the constant shear forces that often exist in tissues.

  16. A cluster randomised trial of cloth masks compared with medical masks in healthcare workers

    PubMed Central

    MacIntyre, C Raina; Seale, Holly; Dung, Tham Chi; Hien, Nguyen Tran; Nga, Phan Thi; Chughtai, Abrar Ahmad; Rahman, Bayzidur; Dwyer, Dominic E; Wang, Quanyi

    2015-01-01

    Objective The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). The null hypothesis is that there is no difference between medical masks and cloth masks. Setting 14 secondary-level/tertiary-level hospitals in Hanoi, Vietnam. Participants 1607 hospital HCWs aged ≥18 years working full-time in selected high-risk wards. Intervention Hospital wards were randomised to: medical masks, cloth masks or a control group (usual practice, which included mask wearing). Participants used the mask on every shift for 4 consecutive weeks. Main outcome measure Clinical respiratory illness (CRI), influenza-like illness (ILI) and laboratory-confirmed respiratory virus infection. Results The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%. Conclusions This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated. Trial registration number Australian New Zealand Clinical Trials Registry: ACTRN12610000887077. PMID

  17. Nuclear and cytoplasmic actin in dinoflagellates.

    PubMed

    Soyer-Gobillard, M O; Ausseil, J; Géraud, M L

    1996-01-01

    Experiments using monoclonal and polyclonal anti-actin antibodies allowed us to demonstrate the presence of F- or G-actin in original protists, dinoflagellates, either by biochemistry, immunofluorescence and in TEM. SDS-PAGE electrophoresis and immunoblottings made either from total or nuclear protein extracts revealed the presence of a 44-kDa band reacting with monoclonal anti-actin antibody in two species, Prorocentrum micans and Crypthecodinium cohnii, and thus demonstrated the presence of actin in nuclear and cytoplasmic fractions. After squash preparation of P micans cells, actin was identified within the nucleus and in some regions of the cytoplasm by immunofluorescence microscopy. Labelling of both the nucleolus and the centrosome region was evident together with amorphous nucleoplasmic material surrounding the chromosomes. The use of cryosections of intact P micans and C cohnii cells for immunofluorescence along with staining with DAPI to delineate the chromosomes themselves, yielded finer resolution of the intranuclear network labelling pattern and allowed us to complete our observations, in particular on the cytoplasmic labelling. In P micans, in addition to the centrosome region, the cytoplasmic channels passing through the nucleus in dividing cells are labelled. In C cohnii, the cortex, the centrosome region, the cytoplasmic channels, the region surrounding the nucleus, the filaments linking it to the cortex and the cleavage furrow are also labelled. In the nucleus of the two species, there is a prominent "weft' of fine actin filaments in the nucleoplasm forming a matrix of varying density around the persistent chromosomes. This actin matrix, of unknown function, is most conspicuous at the end of the S-phase of the cell cycle. Fluorescent derivatives of phalloidin, used as diagnostic cytochemical probes for polymeric actin (F-actin), gave similar results. Positive TEM immunolabelling of intranuclear actin confirms its presence in the nucleoplasm, in the

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

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

    SRAF (sub-resolution assist feature) generation technology has been a popular resolution enhancement technique in photo-lithography past sub-65nm node. It helps to increase the process window, and these are some times called ILT(inverse lithography technology). Also, many studies have been presented on how to determine the best positions of SRAFs, and optimize its size. According to these reports, the generation of SRAF can be formulated as a constrained optimization problem. The constraints are the side lobe suppression and allowable minimum feature size or MRC (mask manufacturing rule check). As we know, bigger SRAF gives better contribution to main feature but susceptible to SRAF side lobe issue. Thus, we finally have no choice but to trade-off the advantages of the ideally optimized mask that contains very complicated SRAF patterns to the layout that has been MRC imposed applied to it. The above dilemma can be resolved by simultaneously using lower dose (high threshold) and cleaning up by smaller MRC. This solution makes the room between threshold (side lobe limitation) and MRC constraint (minimum feature limitation) wider. In order to use smaller MRC restriction without considering the mask writing and inspection issue, it is also appropriate to identify the exact mask writing limitation and find the smart mask constraints that well reflect the mask manufacturability and the e-beam lithography characteristics. In this article, we discuss two main topics on mask optimizations with SRAF. The first topic is on the experimental work to find what behavior of the mask writing ability is in term of several MRC parameters, and we propose more effective MRC constraint for aggressive generation of SRAF. The next topic is on finding the optimum MRC condition in practical case, 3X nm node DRAM contact layer. In fact, it is not easy to encompass the mask writing capability for very complicate real SRAF pattern by using the current MRC constraint based on the only width and

  19. Interactions of actin, myosin, and an actin-binding protein of chronic myelogenous leukemia leukocytes.

    PubMed Central

    Boxer, L A; Stossel, T P

    1976-01-01

    Actin, myosin, and a high molecular weight actin-binding protein were purified from chronic myelogenous leukemia (CML) leukocytes. CML leukocyte actin resembled skeletal muscle and other cytoplasmic actins by its subunit molecular weight, by its ability to polymerize in the presence of salts, and to activate the Mg2+-ATPase activity of rabbit skeletal muscle myosin. CML leukocyte myosin was similar to other vertebrate cytoplasmic myosins in having heavy chains and two light subunits. However, its apparent heavy-chain molecular weight and Stokes radius suggested that it was variably degraded during purification. Purified CML leukocyte myosin had average specific EDTA- AND Ca2+-activated ATPase activities of 125 and 151 nmol Pi released/mg protein per min, respectively and low specific Mg2+-ATPase activity. The Mg2+-ATPase activity of CML myosin was increased 200-fold by rabbit skeletal muscle F-actin, but the specific activity relative to that of actin-activated rabbit skeletal muscle myosin was low. CML leukocyte myosin, like other vertebrate cytoplasmic myosins, formed filaments in 0.1 M KCl solutions. Reduced and denatured CML leukocyte-actin-binding protein had a single high molecular weight subunit like a recently described actin-binding protein of rabbit pulmonary macrophages which promotes the polymerization and gelation of actin. Cytoplasmic extracts of CML leukocytes prepared with ice-cold 0.34-M sucrose solutions containing Mg2+-ATP, dithiothreitol, and EDTA at pH 7.0 underwent rapid gelation when warmed to 25 degrees C. Initially, the gel could be liquified by cooling to ice-bath temperature. With time, warmed cytoplasmic extract gels shrunk ("contracted") into aggregates. The following findings indicated that CML leukocyte actin-binding protein promoted the temperature-dependent gelation of actin in the cytoplasmic extracts and that CML leukocyte myosin was involved in the contraction of the actin gels: (a) Cytoplasmic extract gels initially contained

  20. Set Size and Mask Duration Do Not Interact in Object-Substitution Masking

    ERIC Educational Resources Information Center

    Argyropoulos, Ioannis; Gellatly, Angus; Pilling, Michael; Carter, Wakefield

    2013-01-01

    Object-substitution masking (OSM) occurs when a mask, such as four dots that surround a brief target item, onsets simultaneously with the target and offsets a short time after the target, rather than simultaneously with it. OSM is a reduction in accuracy of reporting the target with the temporally trailing mask, compared with the simultaneously…

  1. IntenCD and mask phase uniformity

    NASA Astrophysics Data System (ADS)

    Cohen, Yaron; Mangan, Shmoolik; Attal, Shay; Ben-Yishay, Michael; Englard, Ilan

    2010-09-01

    The allowable wafer Critical Dimension Uniformity (CDU) budget of the 2x node poses stringent requirements on mask induced errors at wafer level. The total CDU budget of 2 nm which is partially consumed by across wafer and field process and imaging variations, leaves little room for additional mask errors to still comply to the overall CDU budget. The trend of higher mask error enhancement factor (MEEF) for advanced technology nodes aggravates this situation further. Traditionally, the assessment of these variations is based on separate critical dimension and phase/transmission measurements. Metrology measurement tools are typically based on different techniques to independently measure each source of non-uniformity and produce the required uniformity maps. Each technique concentrates on a single physical property (e.g., line-width, phase, transmission, etc.) and requires special calibration for the required accuracy, precision and its transformation from mask to the wafer nanometer domain. An alternative to all these separate measurements is proposed by using the IntenCDTM application based on the aerial image of the mask. This alternative approach provides a map of mask-induced, printed CD variations across the photomask. In this paper, a study is presented to estimate mask-induced printed CDU at wafer level from the aerial image and results are compared to mask- and phase-CD measurements. The work shows that a single aerial IntenCD map can replace the two sets of data based on mask-CD and mask-phase measurements and allows for prediction of the mask contribution to overall printed CDU.

  2. 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.

  3. Shadows Alter Facial Expressions of Noh Masks

    PubMed Central

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

    2013-01-01

    Background A Noh mask, worn by expert actors during performance on the Japanese traditional Noh drama, conveys various emotional expressions despite its fixed physical properties. How does the mask change its expressions? Shadows change subtly during the actual Noh drama, which plays a key role in creating elusive artistic enchantment. We here describe evidence from two experiments regarding how attached shadows of the Noh masks influence the observers’ recognition of the emotional expressions. Methodology/Principal Findings In Experiment 1, neutral-faced Noh masks having the attached shadows of the happy/sad masks were recognized as bearing happy/sad expressions, respectively. This was true for all four types of masks each of which represented a character differing in sex and age, even though the original characteristics of the masks also greatly influenced the evaluation of emotions. Experiment 2 further revealed that frontal Noh mask images having shadows of upward/downward tilted masks were evaluated as sad/happy, respectively. This was consistent with outcomes from preceding studies using actually tilted Noh mask images. Conclusions/Significance Results from the two experiments concur that purely manipulating attached shadows of the different types of Noh masks significantly alters the emotion recognition. These findings go in line with the mysterious facial expressions observed in Western paintings, such as the elusive qualities of Mona Lisa’s smile. They also agree with the aesthetic principle of Japanese traditional art “yugen (profound grace and subtlety)”, which highly appreciates subtle emotional expressions in the darkness. PMID:23940748

  4. Defining a core set of actin cytoskeletal proteins critical for actin-based motility of Rickettsia.

    PubMed

    Serio, Alisa W; Jeng, Robert L; Haglund, Cat M; Reed, Shawna C; Welch, Matthew D

    2010-05-20

    Many Rickettsia species are intracellular bacterial pathogens that use actin-based motility for spread during infection. However, while other bacteria assemble actin tails consisting of branched networks, Rickettsia assemble long parallel actin bundles, suggesting the use of a distinct mechanism for exploiting actin. To identify the underlying mechanisms and host factors involved in Rickettsia parkeri actin-based motility, we performed an RNAi screen targeting 115 actin cytoskeletal genes in Drosophila cells. The screen delineated a set of four core proteins-profilin, fimbrin/T-plastin, capping protein, and cofilin--as crucial for determining actin tail length, organizing filament architecture, and enabling motility. In mammalian cells, these proteins were localized throughout R. parkeri tails, consistent with a role in motility. Profilin and fimbrin/T-plastin were critical for the motility of R. parkeri but not Listeria monocytogenes. Our results highlight key distinctions between the evolutionary strategies and molecular mechanisms employed by bacterial pathogens to assemble and organize actin. PMID:20478540

  5. SelR reverses Mical-mediated oxidation of actin to regulate F-actin dynamics.

    PubMed

    Hung, Ruei-Jiun; Spaeth, Christopher S; Yesilyurt, Hunkar Gizem; Terman, Jonathan R

    2013-12-01

    Actin's polymerization properties are markedly altered by oxidation of its conserved Met 44 residue. Mediating this effect is a specific oxidation-reduction (redox) enzyme, Mical, that works with Semaphorin repulsive guidance cues and selectively oxidizes Met 44. We now find that this actin-regulatory process is reversible. Employing a genetic approach, we identified a specific methionine sulfoxide reductase (MsrB) enzyme SelR that opposes Mical redox activity and Semaphorin-Plexin repulsion to direct multiple actin-dependent cellular behaviours in vivo. SelR specifically catalyses the reduction of the R isomer of methionine sulfoxide (methionine-R-sulfoxide) to methionine, and we found that SelR directly reduced Mical-oxidized actin, restoring its normal polymerization properties. These results indicate that Mical oxidizes actin stereospecifically to generate actin Met-44-R-sulfoxide (actin(Met(R)O-44)), and also implicate the interconversion of specific Met/Met(R)O residues as a precise means to modulate protein function. Our results therefore uncover a specific reversible redox actin regulatory system that controls cell and developmental biology.

  6. 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.

  7. 42 CFR 84.117 - Gas mask containers; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Gas mask containers; minimum requirements. 84.117... § 84.117 Gas mask containers; minimum requirements. (a) Gas masks shall be equipped with a substantial... mask it contains and all appropriate approval labels. (b) Containers for gas masks shall be...

  8. 42 CFR 84.117 - Gas mask containers; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Gas mask containers; minimum requirements. 84.117... § 84.117 Gas mask containers; minimum requirements. (a) Gas masks shall be equipped with a substantial... mask it contains and all appropriate approval labels. (b) Containers for gas masks shall be...

  9. 42 CFR 84.117 - Gas mask containers; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Gas mask containers; minimum requirements. 84.117... § 84.117 Gas mask containers; minimum requirements. (a) Gas masks shall be equipped with a substantial... mask it contains and all appropriate approval labels. (b) Containers for gas masks shall be...

  10. 42 CFR 84.110 - Gas masks; description.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Gas masks; description. 84.110 Section 84.110... HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.110 Gas masks; description. (a) Gas masks including all completely assembled air purifying masks designed...

  11. 42 CFR 84.110 - Gas masks; description.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Gas masks; description. 84.110 Section 84.110... HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.110 Gas masks; description. (a) Gas masks including all completely assembled air purifying masks designed...

  12. 42 CFR 84.110 - Gas masks; description.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Gas masks; description. 84.110 Section 84.110... HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.110 Gas masks; description. (a) Gas masks including all completely assembled air purifying masks designed...

  13. EUV Dark-Field Microscopy for Defect Inspection

    SciTech Connect

    Juschkin, L.; Maryasov, A.; Herbert, S.; Aretz, A.; Bergmann, K.; Lebert, R.

    2011-09-09

    An actinic EUV microscope for defect detection on mask blanks for operation in dark field using a table-top discharge-produced plasma source has been developed. Several test structures (pits and bumps) on multilayer mirrors were investigated by our Schwarzschild objective-based EUV microscope at 13.5-nm wavelength and then characterized with an atomic force microscope. Possible defect-detection limits with large field of view and moderate magnification are discussed in terms of required irradiation dose and system performance.

  14. Novel glass inspection method for advanced photomask blanks

    NASA Astrophysics Data System (ADS)

    Tanabe, Masaru; Kikuchi, Toshiharu; Hashimoto, Masahiro; Ohkubo, Yasushi

    2007-05-01

    Recently, extremely-high-quality-quartz substrates have been demanded for advancing ArF-lithography. HOYA has developed a novel inspection method for interior defects as well as surface defects. The total internal reflection of the substrate is employed to produce an ideal dark field illumination. The novel inspection method can detect a "nano-pit" of 12nm-EDS, the Equivalent of the Diameter of a Sphere (EDS). It will meet the sensitivity for 32nm node and beyond. Moreover, a type of unique defect is detected, which induces Serious Transmittance Error for Arf-LiTHography. We call it the "STEALTH" defect. It is a killer defect in wafer printing; but it cannot be detected with any conventional inspection in the mask-making process so far. In this paper, the performance of the novel inspection method for quartz substrates and the investigation of "STEALTH" are reported.

  15. Lamellipodin promotes actin assembly by clustering Ena/VASP proteins and tethering them to actin filaments.

    PubMed

    Hansen, Scott D; Mullins, R Dyche

    2015-01-01

    Enabled/Vasodilator (Ena/VASP) proteins promote actin filament assembly at multiple locations, including: leading edge membranes, focal adhesions, and the surface of intracellular pathogens. One important Ena/VASP regulator is the mig-10/Lamellipodin/RIAM family of adaptors that promote lamellipod formation in fibroblasts and drive neurite outgrowth and axon guidance in neurons. To better understand how MRL proteins promote actin network formation we studied the interactions between Lamellipodin (Lpd), actin, and VASP, both in vivo and in vitro. We find that Lpd binds directly to actin filaments and that this interaction regulates its subcellular localization and enhances its effect on VASP polymerase activity. We propose that Lpd delivers Ena/VASP proteins to growing barbed ends and increases their polymerase activity by tethering them to filaments. This interaction represents one more pathway by which growing actin filaments produce positive feedback to control localization and activity of proteins that regulate their assembly.

  16. Septins promote F-actin ring formation by crosslinking actin filaments into curved bundles.

    PubMed

    Mavrakis, Manos; Azou-Gros, Yannick; Tsai, Feng-Ching; Alvarado, José; Bertin, Aurélie; Iv, Francois; Kress, Alla; Brasselet, Sophie; Koenderink, Gijsje H; Lecuit, Thomas

    2014-04-01

    Animal cell cytokinesis requires a contractile ring of crosslinked actin filaments and myosin motors. How contractile rings form and are stabilized in dividing cells remains unclear. We address this problem by focusing on septins, highly conserved proteins in eukaryotes whose precise contribution to cytokinesis remains elusive. We use the cleavage of the Drosophila melanogaster embryo as a model system, where contractile actin rings drive constriction of invaginating membranes to produce an epithelium in a manner akin to cell division. In vivo functional studies show that septins are required for generating curved and tightly packed actin filament networks. In vitro reconstitution assays show that septins alone bundle actin filaments into rings, accounting for the defects in actin ring formation in septin mutants. The bundling and bending activities are conserved for human septins, and highlight unique functions of septins in the organization of contractile actomyosin rings.

  17. Electronic Inspection of Beef

    NASA Technical Reports Server (NTRS)

    Anselmo, Victor J.; Gammell, Paul M.; Clark, Jerry

    1987-01-01

    Two proposed methods for grading beef quality based on inspection by electronic equipment: one method uses television camera to generate image of a cut of beef as customer sees it; other uses ultrasonics to inspect live animal or unsliced carcasses. Both methods show promise for automated meat inspection.

  18. Software Formal Inspections Guidebook

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Software Formal Inspections Guidebook is designed to support the inspection process of software developed by and for NASA. This document provides information on how to implement a recommended and proven method for conducting formal inspections of NASA software. This Guidebook is a companion document to NASA Standard 2202-93, Software Formal Inspections Standard, approved April 1993, which provides the rules, procedures, and specific requirements for conducting software formal inspections. Application of the Formal Inspections Standard is optional to NASA program or project management. In cases where program or project management decide to use the formal inspections method, this Guidebook provides additional information on how to establish and implement the process. The goal of the formal inspections process as documented in the above-mentioned Standard and this Guidebook is to provide a framework and model for an inspection process that will enable the detection and elimination of defects as early as possible in the software life cycle. An ancillary aspect of the formal inspection process incorporates the collection and analysis of inspection data to effect continual improvement in the inspection process and the quality of the software subjected to the process.

  19. Arabidopsis ACTIN-DEPOLYMERIZING FACTOR7 Severs Actin Filaments and Regulates Actin Cable Turnover to Promote Normal Pollen Tube Growth[W

    PubMed Central

    Zheng, Yiyan; Xie, Yurong; Jiang, Yuxiang; Qu, Xiaolu; Huang, Shanjin

    2013-01-01

    Actin filaments are often arranged into higher-order structures, such as the longitudinal actin cables that generate the reverse fountain cytoplasmic streaming pattern present in pollen tubes. While several actin binding proteins have been implicated in the generation of these cables, the mechanisms that regulate their dynamic turnover remain largely unknown. Here, we show that Arabidopsis thaliana ACTIN-DEPOLYMERIZING FACTOR7 (ADF7) is required for turnover of longitudinal actin cables. In vitro biochemical analyses revealed that ADF7 is a typical ADF that prefers ADP-G-actin over ATP-G-actin. ADF7 inhibits nucleotide exchange on actin and severs filaments, but its filament severing and depolymerizing activities are less potent than those of the vegetative ADF1. ADF7 primarily decorates longitudinal actin cables in the shanks of pollen tubes. Consistent with this localization pattern, the severing frequency and depolymerization rate of filaments significantly decreased, while their maximum lifetime significantly increased, in adf7 pollen tube shanks. Furthermore, an ADF7–enhanced green fluorescent protein fusion with defective severing activity but normal G-actin binding activity could not complement adf7, providing compelling evidence that the severing activity of ADF7 is vital for its in vivo functions. These observations suggest that ADF7 evolved to promote turnover of longitudinal actin cables by severing actin filaments in pollen tubes. PMID:24058157

  20. Purification and Characterization of Actin from Maize Pollen 1

    PubMed Central

    Liu, Xiong; Yen, Lung-Fei

    1992-01-01

    Pollen is an excellent source of actin for biochemical and physiological studies of the actomyosin system in higher plants. We have developed an efficient method to prepare relatively high levels of actin from the pollen of maize (Zea mays L.). The procedures of purification include acetone powder preparation, saturated ammonium sulfate fractionation, diethylaminoethyl-cellulose chromatography, a cycle of polymerization-depolymerization, and Sephacryl S-200 gel filtration. The average yield of actin is 19 milligrams per 100 grams of pollen grains extracted. This is comparable with those of Acanthamoeba castellanii and human platelets. The purified pollen actin is electrophoretically homogeneous and its molecular mass is 42 kilodaltons. The amino acid composition and circular dichroism spectrum of pollen actin are identical to those of muscle actin. The actin purified from pollen is able to polymerize to F-actin. The pollen F-actin activated the activity of the muscle myosin ATPase sevenfold. ImagesFigure 1Figure 2 PMID:16668982

  1. Tau co-organizes dynamic microtubule and actin networks

    PubMed Central

    Elie, Auréliane; Prezel, Elea; Guérin, Christophe; Denarier, Eric; Ramirez-Rios, Sacnicte; Serre, Laurence; Andrieux, Annie; Fourest-Lieuvin, Anne; Blanchoin, Laurent; Arnal, Isabelle

    2015-01-01

    The crosstalk between microtubules and actin is essential for cellular functions. However, mechanisms underlying the microtubule-actin organization by cross-linkers remain largely unexplored. Here, we report that tau, a neuronal microtubule-associated protein, binds to microtubules and actin simultaneously, promoting in vitro co-organization and coupled growth of both networks. By developing an original assay to visualize concomitant microtubule and actin assembly, we show that tau can induce guided polymerization of actin filaments along microtubule tracks and growth of single microtubules along actin filament bundles. Importantly, tau mediates microtubule-actin co-alignment without changing polymer growth properties. Mutagenesis studies further reveal that at least two of the four tau repeated motifs, primarily identified as tubulin-binding sites, are required to connect microtubules and actin. Tau thus represents a molecular linker between microtubule and actin networks, enabling a coordination of the two cytoskeletons that might be essential in various neuronal contexts. PMID:25944224

  2. 21 CFR 868.5590 - Scavenging mask.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification....

  3. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask....

  4. 21 CFR 868.5590 - Scavenging mask.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification....

  5. 21 CFR 868.5590 - Scavenging mask.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification....

  6. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask....

  7. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask....

  8. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask....

  9. 21 CFR 868.5590 - Scavenging mask.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification....

  10. 21 CFR 868.5590 - Scavenging mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification....

  11. 21 CFR 868.5570 - Nonrebreathing mask.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonrebreathing mask. 868.5570 Section 868.5570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5570 Nonrebreathing mask....

  12. 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),…

  13. Computing Challenges in Coded Mask Imaging

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald

    2009-01-01

    This slide presaentation reviews the complications and challenges in developing computer systems for Coded Mask Imaging telescopes. The coded mask technique is used when there is no other way to create the telescope, (i.e., when there are wide fields of view, high energies for focusing or low energies for the Compton/Tracker Techniques and very good angular resolution.) The coded mask telescope is described, and the mask is reviewed. The coded Masks for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) instruments are shown, and a chart showing the types of position sensitive detectors used for the coded mask telescopes is also reviewed. Slides describe the mechanism of recovering an image from the masked pattern. The correlation with the mask pattern is described. The Matrix approach is reviewed, and other approaches to image reconstruction are described. Included in the presentation is a review of the Energetic X-ray Imaging Survey Telescope (EXIST) / High Energy Telescope (HET), with information about the mission, the operation of the telescope, comparison of the EXIST/HET with the SWIFT/BAT and details of the design of the EXIST/HET.

  14. Incorporation of mammalian actin into microfilaments in plant cell nucleus

    PubMed Central

    Paves, Heiti; Truve, Erkki

    2004-01-01

    Background Actin is an ancient molecule that shows more than 90% amino acid homology between mammalian and plant actins. The regions of the actin molecule that are involved in F-actin assembly are largely conserved, and it is likely that mammalian actin is able to incorporate into microfilaments in plant cells but there is no experimental evidence until now. Results Visualization of microfilaments in onion bulb scale epidermis cells by different techniques revealed that rhodamine-phalloidin stained F-actin besides cytoplasm also in the nuclei whereas GFP-mouse talin hybrid protein did not enter the nuclei. Microinjection of fluorescently labeled actin was applied to study the presence of nuclear microfilaments in plant cells. Ratio imaging of injected fluorescent rabbit skeletal muscle actin and phalloidin staining of the microinjected cells showed that mammalian actin was able to incorporate into plant F-actin. The incorporation occurred preferentially in the nucleus and in the perinuclear region of plant cells whereas part of plant microfilaments, mostly in the periphery of cytoplasm, did not incorporate mammalian actin. Conclusions Microinjected mammalian actin is able to enter plant cell's nucleus, whereas incorporation of mammalian actin into plant F-actin occurs preferentially in the nucleus and perinuclear area. PMID:15102327

  15. The EGF receptor is an actin-binding protein

    PubMed Central

    1992-01-01

    In a number of recent studies it has been shown that in vivo part of the EGF receptor (EGFR) population is associated to the actin filament system. In this paper we demonstrate that the purified EGFR can be cosedimented with purified filamentous actin (F-actin) indicating a direct association between EGFR and actin. A truncated EGFR, previously shown not to be associated to the cytoskeleton, was used as a control and this receptor did not cosediment with actin filaments. Determination of the actin-binding domain of the EGFR was done by measuring competition of either a polyclonal antibody or synthetic peptides on EGFR cosedimentation with F-actin. A synthetic peptide was made homologous to amino acid residues 984-996 (HL-33) of the EGFR which shows high homology with the actin-binding domain of Acanthamoeba profilin. A polyclonal antibody raised against HL-33 was found to prevent cosedimentation of EGFR with F-actin. This peptide HL-33 was shown to bind directly to actin in contrast with a synthetic peptide homologous to residues 1001-1013 (HL-34). During cosedimentation, HL-33 competed for actin binding of the EGFR and HL-34 did not, indicating that the EGFR contains one actin-binding site. These results demonstrate that the EGFR is an actin-binding protein which binds to actin via a domain containing amino acids residues 984-996. PMID:1383230

  16. Crystal structure of a nuclear actin ternary complex.

    PubMed

    Cao, Tingting; Sun, Lingfei; Jiang, Yuxiang; Huang, Shanjin; Wang, Jiawei; Chen, Zhucheng

    2016-08-01

    Actin polymerizes and forms filamentous structures (F-actin) in the cytoplasm of eukaryotic cells. It also exists in the nucleus and regulates various nucleic acid transactions, particularly through its incorporation into multiple chromatin-remodeling complexes. However, the specific structure of actin and the mechanisms that regulate its polymeric nature inside the nucleus remain unknown. Here, we report the crystal structure of nuclear actin (N-actin) complexed with actin-related protein 4 (Arp4) and the helicase-SANT-associated (HSA) domain of the chromatin remodeler Swr1. The inner face and barbed end of N-actin are sequestered by interactions with Arp4 and the HSA domain, respectively, which prevents N-actin from polymerization and binding to many actin regulators. The two major domains of N-actin are more twisted than those of globular actin (G-actin), and its nucleotide-binding pocket is occluded, freeing N-actin from binding to and regulation by ATP. These findings revealed the salient structural features of N-actin that distinguish it from its cytoplasmic counterpart and provide a rational basis for its functions and regulation inside the nucleus. PMID:27457955

  17. The actinome of Dictyostelium discoideum in comparison to actins and actin-related proteins from other organisms.

    PubMed

    Joseph, Jayabalan M; Fey, Petra; Ramalingam, Nagendran; Liu, Xiao I; Rohlfs, Meino; Noegel, Angelika A; Müller-Taubenberger, Annette; Glöckner, Gernot; Schleicher, Michael

    2008-07-09

    Actin belongs to the most abundant proteins in eukaryotic cells which harbor usually many conventional actin isoforms as well as actin-related proteins (Arps). To get an overview over the sometimes confusing multitude of actins and Arps, we analyzed the Dictyostelium discoideum actinome in detail and compared it with the genomes from other model organisms. The D. discoideum actinome comprises 41 actins and actin-related proteins. The genome contains 17 actin genes which most likely arose from consecutive gene duplications, are all active, in some cases developmentally regulated and coding for identical proteins (Act8-group). According to published data, the actin fraction in a D. discoideum cell consists of more than 95% of these Act8-type proteins. The other 16 actin isoforms contain a conventional actin motif profile as well but differ in their protein sequences. Seven actin genes are potential pseudogenes. A homology search of the human genome using the most typical D. discoideum actin (Act8) as query sequence finds the major actin isoforms such as cytoplasmic beta-actin as best hit. This suggests that the Act8-group represents a nearly perfect actin throughout evolution. Interestingly, limited data from D. fasciculatum, a more ancient member among the social amoebae, show different relationships between conventional actins. The Act8-type isoform is most conserved throughout evolution. Modeling of the putative structures suggests that the majority of the actin-related proteins is functionally unrelated to canonical actin. The data suggest that the other actin variants are not necessary for the cytoskeleton itself but rather regulators of its dynamical features or subunits in larger protein complexes.

  18. Protein contamination of the Laryngeal Mask Airway and its relationship to re-use.

    PubMed

    Greenwood, J; Green, N; Power, G

    2006-06-01

    The Laryngeal Mask Airway is a reusable device for maintaining the patency of a patient's airway during general anaesthesia. The device can be reused after it has been cleaned and sterilized. Protein contamination of medical instruments is a concern and has been found to occur despite standard sterilization techniques. The reason for the concern relates to the possibility of the transmission of prions and the risk of developing a neurodegenerative disorder such as Creutzveldt-Jacob disease. The purpose of this study was to quantify the amount of protein contamination that occurs, and to relate this to the number of times the Laryngeal Mask Airway has been used. Fifty previously used Classic Laryngeal Masks were collected after routine sterilization and packaging. The devices were immersed in protein detecting stain and then visual inspection performed to assess the degree and distribution of the staining. The researcher was blinded to the number of times the Laryngeal Mask Airway had been used. Linear regression analysis of the degrees of staining of the airway revealed that protein contamination occurs after the first use of the device and this increases with each subsequent use. This finding highlights the concern that the currently used cleaning and sterilization methods do not prevent the accumulation of proteinaceous material on Laryngeal Mask Airways. Consideration should be given to the search for more efficient cleaning and sterilization techniques or the use of disposable devices. PMID:16802488

  19. Impact of Carbon Nanomaterials on Actin Polymerization.

    PubMed

    Dong, Ying; Sun, Haiyan; Li, Xu; Li, Xin; Zhao, Lina

    2016-03-01

    Many nanomaterials have entered people's daily lives and impact the normal process of biological entities consequently. As one kind of the important nanomaterials, carbon based nanomaterials have invoked a lot of concerns from scientific researches because of their unique physicochemical properties. In eukaryotes, actin is the most abundantly distributed protein in both cytoplasm and cell nucleus, and closely controls the cell proliferation and mobility. Recently, many investigations have found some carbon based nanomaterials can affect actin cytoskeleton remarkably, including fullerenes derivatives, carbon nanotubes, graphene and its derivatives. However, these interaction processes are complicated and the underlying mechanism is far from being understood clearly. In this review, we discussed the different mechanisms of carbon nanomaterials impact on actin polymerization into three pathways, as triggering the signaling pathways from carbon nanomaterials outside of cells, increasing the production of reactive oxygen species from carbon nanomaterials inside of cells and direct interaction from carbon nanomaterials inside of cells. As a result, the dimension and size of carbon nanomaterials play a key role in regulation of actin cytoskeleton. Furthermore, we forecasted the possible investigation strategy for meeting the challenges of the future study on this topic. We hope the findings are helpful in understanding the molecular mechanism in carbon nanomaterials regulating actin polymerization, and provide new insight in novel nanomedicine development for inhibition tumor cell migration. PMID:27455649

  20. EUV mask defect mitigation through pattern placement

    NASA Astrophysics Data System (ADS)

    Burns, John; Abbas, Mansoor

    2010-09-01

    One of the challenges of EUVL is to bring EUV mask blank defect levels to zero. With uncertainty on when defect free masks may be routinely available, we explore a possibility for effectively using defective EUV mask blanks in production with a defect avoidance strategy. The key idea is to position the pattern/layout on the blank where the defects do not impact the final wafer image. Assuming that layout designs contain some non-critical areas in which defects can be safely positioned, it may be possible to align these regions with a given, small set of defect positions mapped from an imperfect mask blank. Using a few representative assortment of current-node, full-chip layout patterns we run multiple trials against real blank defect maps with various defect counts successfully. Our goal is to assess the probabilities that defect avoidance will work as a function of mask blank defect count, and by lithography layer.

  1. EUVL mask substrate specifications (wafer-type)

    SciTech Connect

    Tong, W

    1999-07-01

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

  2. Software Formal Inspections Standard

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This Software Formal Inspections Standard (hereinafter referred to as Standard) is applicable to NASA software. This Standard defines the requirements that shall be fulfilled by the software formal inspections process whenever this process is specified for NASA software. The objective of this Standard is to define the requirements for a process that inspects software products to detect and eliminate defects as early as possible in the software life cycle. The process also provides for the collection and analysis of inspection data to improve the inspection process as well as the quality of the software.

  3. A new F-actin structure in fungi: actin ring formation around the cell nucleus of Cryptococcus neoformans.

    PubMed

    Kopecká, Marie; Kawamoto, Susumu; Yamaguchi, Masashi

    2013-04-01

    The F-actin cytoskeleton of Cryptococcus neoformans is known to comprise actin cables, cortical patches and cytokinetic ring. Here, we describe a new F-actin structure in fungi, a perinuclear F-actin collar ring around the cell nucleus, by fluorescent microscopic imaging of rhodamine phalloidin-stained F-actin. Perinuclear F-actin rings form in Cryptococcus neoformans treated with the microtubule inhibitor Nocodazole or with the drug solvent dimethyl sulfoxide (DMSO) or grown in yeast extract peptone dextrose (YEPD) medium, but they are absent in cells treated with Latrunculin A. Perinuclear F-actin rings may function as 'funicular cabin' for the cell nucleus, and actin cables as intracellular 'funicular' suspending nucleus in the central position in the cell and moving nucleus along the polarity axis along actin cables.

  4. Structural Transitions of F-Actin:Espin Bundles

    NASA Astrophysics Data System (ADS)

    Purdy, Kirstin; Bartles, James; Wong, Gerard

    2006-03-01

    Espin is an actin bundling protein involved in the formation of the parallel bundles of filamentous actin in hair cell stereocilia. Mutations in espin are implicated in deafness phenotypes in mice and humans. We present measurements of the F-actin structures induced by wild type and by mutated espin obtained via small angle x-ray scattering and fluorescence microscopy. We found that wild type espin induced a paracrystalline hexagonal array of twisted F-actin, whereas the mutated espin only condensed the F-actin into a nematic-like phase. The possibility of coexisting nematic and bundled actin in mixtures containing both mutant and wild type espins was also investigated.

  5. Cheap Face Masks Little Help Against Air Pollutants

    MedlinePlus

    ... News) -- Inexpensive cloth masks offer little protection against air pollution, a new study suggests. Many people in Asia ... or washable cloth masks to protect against small air pollution particles. But tests on different types of masks ...

  6. Nuclear actin and lamins in viral infections.

    PubMed

    Cibulka, Jakub; Fraiberk, Martin; Forstova, Jitka

    2012-03-01

    Lamins are the best characterized cytoskeletal components of the cell nucleus that help to maintain the nuclear shape and participate in diverse nuclear processes including replication or transcription. Nuclear actin is now widely accepted to be another cytoskeletal protein present in the nucleus that fulfills important functions in the gene expression. Some viruses replicating in the nucleus evolved the ability to interact with and probably utilize nuclear actin for their replication, e.g., for the assembly and transport of capsids or mRNA export. On the other hand, lamins play a role in the propagation of other viruses since nuclear lamina may represent a barrier for virions entering or escaping the nucleus. This review will summarize the current knowledge about the roles of nuclear actin and lamins in viral infections.

  7. Actin Filament Segmentation Using Dynamic Programming

    PubMed Central

    Li, Hongsheng; Shen, Tian; Huang, Xiaolei

    2011-01-01

    We introduce a novel algorithm for actin filament segmentation in 2D TIRFM image sequences. This problem is difficult because actin filaments dynamically change shapes during their growth, and the TIRFM images are usually noisy. We ask a user to specify the two tips of a filament of interest in the first frame. We then model the segmentation problem in an image sequence as a temporal chain, where its states are tip locations; given candidate tip locations, actin filaments' body points are inferred by a dynamic programming method, which adaptively generates candidate solutions. Combining candidate tip locations and their inferred body points, the temporal chain model is efficiently optimized using another dynamic programming method. Evaluation on noisy TIRFM image sequences demonstrates the accuracy and robustness of this approach. PMID:21761674

  8. Spontaneous actin dynamics in contractile rings

    NASA Astrophysics Data System (ADS)

    Kruse, Karsten; Wollrab, Viktoria; Thiagarajan, Raghavan; Wald, Anne; Riveline, Daniel

    Networks of polymerizing actin filaments are known to be capable to self-organize into a variety of structures. For example, spontaneous actin polymerization waves have been observed in living cells in a number of circumstances, notably, in crawling neutrophils and slime molds. During later stages of cell division, they can also spontaneously form a contractile ring that will eventually cleave the cell into two daughter cells. We present a framework for describing networks of polymerizing actin filaments, where assembly is regulated by various proteins. It can also include the effects of molecular motors. We show that the molecular processes driven by these proteins can generate various structures that have been observed in contractile rings of fission yeast and mammalian cells. We discuss a possible functional role of each of these patterns. The work was supported by Agence Nationale de la Recherche, France, (ANR-10-LABX-0030-INRT) and by Deutsche Forschungsgemeinschaft through SFB1027.

  9. Nasal mask ventilation is better than face mask ventilation in edentulous patients

    PubMed Central

    Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

    2016-01-01

    Background and Aims: Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Material and Methods: Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. Results: A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Conclusion: Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients. PMID:27625477

  10. Nasal mask ventilation is better than face mask ventilation in edentulous patients

    PubMed Central

    Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

    2016-01-01

    Background and Aims: Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Material and Methods: Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. Results: A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Conclusion: Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    film for the device. In addition to the increase in complexity of the mask, introduction of EUVL requires infrastructure development of new substrate, mask blank, and finished reticle inspection tools and techniques for handling and storage of a mask without a pellicle. This paper will highlight recent advances in the ability to produce pilot line quality EUV mask blanks to meet the near-term requirements and review the existing technology gaps which must be closed to extend the current capability to meet HVM needs. A special focus will be put on substrate and mask blank defect densities; other process and infrastructure challenges will also be discussed.

  12. Inspection 13.2 nm table-top full-field microscope

    SciTech Connect

    Brizuela, F.; Wang, Y.; Brewer, C. A.; Pedaci, F.; Chao, W.; Anderson, E. H.; Liu, Y.; Goldberg, K. A.; Naulleau, P.; Wachulak, P.; Marconi, M. C.; Attwood, D. T.; Rocca, J. J.; Menoni, C. S.

    2009-02-23

    We present results on a table-top microscope that uses an EUV stepper geometry to capture full-field images with a halfpitch spatial resolution of 55 nm. This microscope uses a 13.2 nm wavelength table-top laser for illumination and acquires images of reflective masks with exposures of 20 seconds. These experiments open the path to the realization of high resolution table-top imaging systems for actinic defect characterization.

  13. Masking property of quantum random cipher with phase mask encryption

    NASA Astrophysics Data System (ADS)

    Sohma, Masaki; Hirota, Osamu

    2014-10-01

    The security analysis of physical encryption protocol based on coherent pulse position modulation (CPPM) originated by Yuen is one of the most interesting topics in the study of cryptosystem with a security level beyond the Shannon limit. Although the implementation of CPPM scheme has certain difficulty, several methods have been proposed recently. This paper deals with the CPPM encryption in terms of symplectic transformation, which includes a phase mask encryption as a special example, and formulates a unified security analysis for such encryption schemes. Specifically, we give a lower bound of Eve's symbol error probability using reliability function theory to ensure that our proposed system exceeds the Shannon limit. Then we assume the secret key is given to Eve after her heterodyne measurement. Since this assumption means that Eve has a great advantage in the sense of the conventional cryptography, the lower bound of her error indeed ensures the security level beyond the Shannon limit. In addition, we show some numerical examples of the security performance.

  14. Human Muscle LIM Protein Dimerizes along the Actin Cytoskeleton and Cross-Links Actin Filaments

    PubMed Central

    Hoffmann, Céline; Moreau, Flora; Moes, Michèle; Luthold, Carole; Dieterle, Monika; Goretti, Emeline; Neumann, Katrin; Steinmetz, André

    2014-01-01

    The muscle LIM protein (MLP) is a nucleocytoplasmic shuttling protein playing important roles in the regulation of myocyte remodeling and adaptation to hypertrophic stimuli. Missense mutations in human MLP or its ablation in transgenic mice promotes cardiomyopathy and heart failure. The exact function(s) of MLP in the cytoplasmic compartment and the underlying molecular mechanisms remain largely unknown. Here, we provide evidence that MLP autonomously binds to, stabilizes, and bundles actin filaments (AFs) independently of calcium and pH. Using total internal reflection fluorescence microscopy, we have shown how MLP cross-links actin filaments into both unipolar and mixed-polarity bundles. Quantitative analysis of the actin cytoskeleton configuration confirmed that MLP substantially promotes actin bundling in live myoblasts. In addition, bimolecular fluorescence complementation (BiFC) assays revealed MLP self-association. Remarkably, BiFC complexes mostly localize along actin filament-rich structures, such as stress fibers and sarcomeres, supporting a functional link between MLP self-association and actin cross-linking. Finally, we have demonstrated that MLP self-associates through its N-terminal LIM domain, whereas it binds to AFs through its C-terminal LIM domain. Together our data support that MLP contributes to the maintenance of cardiomyocyte cytoarchitecture by a mechanism involving its self-association and actin filament cross-linking. PMID:24934443

  15. Fatal congenital myopathy with actin filament deposits.

    PubMed

    Bornemann, A; Petersen, M B; Schmalbruch, H

    1996-07-01

    We present the clinical and morphological findings in a case of progressive congenital myopathy. The symptoms present at birth included severe general muscular hypotonia, diffuse muscular atrophy, arthrogryposis, absence of spontaneous movements, and left ventricular hypertrophy. A biopsy specimen taken from the gastrocnemius muscle when the patient was 2 weeks old revealed deposits which consisted of actin filaments as shown by electron microscopy. The infant was occasionally respirator dependent but was mostly able to breathe unassisted. At the age of 5 months he died of respiratory failure. The actin filament deposits may explain the clinical findings.

  16. Actin Age Orchestrates Myosin-5 and Myosin-6 Runlengths

    PubMed Central

    Zimmermann, Dennis; Santos, Alicja; Kovar, David R.; Rock, Ronald S.

    2015-01-01

    Summary Unlike a static and immobile skeleton, the actin cytoskeleton is a highly dynamic network of filamentous actin (F-actin) polymers that continuously turn over. In addition to generating mechanical forces and sensing mechanical deformation, dynamic F-actin networks serve as cellular tracks for myosin motor traffic. However, much of our mechanistic understanding of processive myosins comes from in vitro studies where motility was studied on pre-assembled and artificially stabilized, static F-actin tracks. In this work, we examine the role of actin dynamics in single-molecule myosin motility using assembling F-actin and the two highly processive motors, myosin-5 and myosin-6. These two myosins have distinct functions in the cell and travel in opposite directions along actin filaments [1–3]. Myosin-5 walks towards the barbed ends of F-actin, traveling to sites of actin polymerization at the cell periphery [4]. Myosin-6 walks towards the pointed end of F-actin [5], traveling towards the cell center along older segments of the actin filament. We find that myosin-5 takes 1.3 to 1.5-fold longer runs on ADP•Pi (young) F-actin, while myosin-6 takes 1.7 to 3.6-fold longer runs along ADP (old) F-actin. These results suggest that conformational differences between ADP•Pi and ADP F-actin tailor these myosins to walk farther toward their preferred actin filament end. Taken together, these experiments define a new mechanism by which myosin traffic may sort to different F-actin networks depending on filament age. PMID:26190073

  17. Functional adaptation between yeast actin and its cognate myosin motors.

    PubMed

    Stark, Benjamin C; Wen, Kuo-Kuang; Allingham, John S; Rubenstein, Peter A; Lord, Matthew

    2011-09-01

    We employed budding yeast and skeletal muscle actin to examine the contribution of the actin isoform to myosin motor function. While yeast and muscle actin are highly homologous, they exhibit different charge density at their N termini (a proposed myosin-binding interface). Muscle myosin-II actin-activated ATPase activity is significantly higher with muscle versus yeast actin. Whether this reflects inefficiency in the ability of yeast actin to activate myosin is not known. Here we optimized the isolation of two yeast myosins to assess actin function in a homogenous system. Yeast myosin-II (Myo1p) and myosin-V (Myo2p) accommodate the reduced N-terminal charge density of yeast actin, showing greater activity with yeast over muscle actin. Increasing the number of negative charges at the N terminus of yeast actin from two to four (as in muscle) had little effect on yeast myosin activity, while other substitutions of charged residues at the myosin interface of yeast actin reduced activity. Thus, yeast actin functions most effectively with its native myosins, which in part relies on associations mediated by its outer domain. Compared with yeast myosin-II and myosin-V, muscle myosin-II activity was very sensitive to salt. Collectively, our findings suggest differing degrees of reliance on electrostatic interactions during weak actomyosin binding in yeast versus muscle. Our study also highlights the importance of native actin isoforms when considering the function of myosins. PMID:21757693

  18. Actin nucleators in the nucleus: an emerging theme.

    PubMed

    Weston, Louise; Coutts, Amanda S; La Thangue, Nicholas B

    2012-08-01

    Actin is an integral component of the cytoskeleton, forming a plethora of macromolecular structures that mediate various cellular functions. The formation of such structures relies on the ability of actin monomers to associate into polymers, and this process is regulated by actin nucleation factors. These factors use monomeric actin pools at specific cellular locations, thereby permitting rapid actin filament formation when required. It has now been established that actin is also present in the nucleus, where it is implicated in chromatin remodelling and the regulation of eukaryotic gene transcription. Notably, the presence of typical actin filaments in the nucleus has not been demonstrated directly. However, studies in recent years have provided evidence for the nuclear localisation of actin nucleation factors that promote cytoplasmic actin polymerisation. Their localisation to the nucleus suggests that these proteins mediate collaboration between the cytoskeleton and the nucleus, which might be dependent on their ability to promote actin polymerisation. The nature of this cooperation remains enigmatic and it will be important to elucidate the physiological relevance of the link between cytoskeletal actin networks and nuclear events. This Commentary explores the current evidence for the nuclear roles of actin nucleation factors. Furthermore, the implication of actin-associated proteins in relaying exogenous signals to the nucleus, particularly in response to cellular stress, will be considered.

  19. Dynamic Regulation of Sarcomeric Actin Filaments in Striated Muscle

    PubMed Central

    Ono, Shoichiro

    2010-01-01

    In striated muscle, the actin cytoskeleton is differentiated into myofibrils. Actin and myosin filaments are organized in sarcomeres and specialized for producing contractile forces. Regular arrangement of actin filaments with uniform length and polarity is critical for the contractile function. However, the mechanisms of assembly and maintenance of sarcomeric actin filaments in striated muscle are not completely understood. Live imaging of actin in striated muscle has revealed that actin subunits within sarcomeric actin filaments are dynamically exchanged without altering overall sarcomeric structures. A number of regulators for actin dynamics have been identified, and malfunction of these regulators often result in disorganization of myofibril structures or muscle diseases. Therefore, proper regulation of actin dynamics in striated muscle is critical for assembly and maintenance of functional myofibrils. Recent studies have suggested that both enhancers of actin dynamics and stabilizers of actin filaments are important for sarcomeric actin organization. Further investigation of the regulatory mechanism of actin dynamics in striated muscle should be a key to understanding how myofibrils develop and operate. © 2010 Wiley-Liss, Inc. PMID:20737540

  20. Actin3 promoter reveals undulating F-actin bundles at shanks and dynamic F-actin meshworks at tips of tip-growing pollen tubes.

    PubMed

    Jásik, Ján; Mičieta, Karol; Siao, Wei; Voigt, Boris; Stuchlík, Stanislav; Schmelzer, Elmon; Turňa, Ján; Baluška, František

    2016-01-01

    The dynamic actin cytoskeleton of pollen tubes is both the driver of the tip growth and the organizer of cell polarity. In order to understand this fast re-arranging cytoskeletal system, we need reliable constructs expressed under relevant promoters. Here we are reporting that the Lifeact reporter, expressed under the pollen-specific Actin3 promoter, visualizes very dynamic F-actin elements both in germinating pollen grains and tip-growing pollen tubes. Importantly, we have documented very active actin polymerization at the cell periphery, especially in the bulging area during pollen germination and in the apical clear zone. Expression of the Lifeact reporter under control of the pollen-specific Actin3 promoter revealed 2 new aspects: (i) long F-actin bundles in pollen tube shanks are dynamic, showing undulating movements, (ii) subapical 'actin collars' or 'fringes' are absent.

  1. Actin3 promoter reveals undulating F-actin bundles at shanks and dynamic F-actin meshworks at tips of tip-growing pollen tubes

    PubMed Central

    Jásik, Ján; Mičieta, Karol; Siao, Wei; Voigt, Boris; Stuchlík, Stanislav; Schmelzer, Elmon; Turňa, Ján; Baluška, František

    2016-01-01

    ABSTRACT The dynamic actin cytoskeleton of pollen tubes is both the driver of the tip growth and the organizer of cell polarity. In order to understand this fast re-arranging cytoskeletal system, we need reliable constructs expressed under relevant promoters. Here we are reporting that the Lifeact reporter, expressed under the pollen-specific Actin3 promoter, visualizes very dynamic F-actin elements both in germinating pollen grains and tip-growing pollen tubes. Importantly, we have documented very active actin polymerization at the cell periphery, especially in the bulging area during pollen germination and in the apical clear zone. Expression of the Lifeact reporter under control of the pollen-specific Actin3 promoter revealed 2 new aspects: (i) long F-actin bundles in pollen tube shanks are dynamic, showing undulating movements, (ii) subapical ‘actin collars’ or ‘fringes’ are absent. PMID:26980067

  2. [Cytoskeletal actin and its associated proteins. Some examples in Protista].

    PubMed

    Guillén, N; Carlier, M F; Brugerolle, G; Tardieux, I; Ausseil, J

    1998-06-01

    Many processes, cell motility being an example, require cells to remodel the actin cytoskeleton in response to both intracellular and extracellular signals. Reorganization of the actin cytoskeleton involves the rapid disassembly and reassembly of actin filaments, a phenomenon regulated by the action of particular actin-binding proteins. In recent years, an interest in studying actin regulation in unicellular organisms has arisen. Parasitic protozoan are among these organisms and studies of the cytoskeleton functions of these protozoan are relevant related to either cell biology or pathogenicity. To discuss recent data in this field, a symposium concerning "Actin and actin-binding proteins in protists" was held on May 8-11 in Paris, France, during the XXXV meeting of the French Society of Protistology. As a brief summary of the symposium we report here findings concerning the in vitro actin dynamic assembly, as well as the characterization of several actin-binding proteins from the parasitic protozoan Entamoeba histolytica, Trichomonas vaginalis and Plasmodium knowlesi. In addition, localization of actin in non-pathogen protists such as Prorocentrum micans and Crypthecodinium cohnii is also presented. The data show that some actin-binding proteins facilitate organization of filaments into higher order structures as pseudopods, while others have regulatory functions, indicating very particular roles for actin-binding proteins. One of the proteins discussed during the symposium, the actin depolymerizing factor ADF, was shown to enhance the treadmilling rate of actin filaments. In vitro, ADF binds to the ADP-bound forms of G-actin and F-actin, thereby participating in and changing the rate of actin assembly. Biochemical approaches allowed the identification of a protein complex formed by HSP/C70-cap32-34 which might also be involved in depolymerization of F-actin in P. knowlesi. Molecular and cellular approaches were used to identify proteins such as ABP-120 and myosin

  3. LCD masks for spatial augmented reality

    NASA Astrophysics Data System (ADS)

    Smithwick, Quinn Y. J.; Reetz, Daniel; Smoot, Lanny

    2014-03-01

    One aim of Spatial Augmented Reality is to visually integrate synthetic objects into real-world spaces amongst physical objects, viewable by many observers without 3D glasses, head-mounted displays or mobile screens. In common implementations, using beam-combiners, scrim projection, or transparent self-emissive displays, the synthetic object's and real-world scene's light combine additively. As a result, synthetic objects appear low-contrast and semitransparent against well-lit backgrounds, and do not cast shadows. These limitations prevent synthetic objects from appearing solid and visually integrated into the real-world space. We use a transparent LCD panel as a programmable dynamic mask. The LCD panel displaying the synthetic object's silhouette mask is colocated with the object's color image, both staying aligned for all points-of-view. The mask blocks the background providing occlusion, presents a black level for high-contrast images, blocks scene illumination thus casting true shadows, and prevents blow-by in projection scrim arrangements. We have several implementations of SAR with LCD masks: 1) beam-combiner with an LCD mask, 2) scrim projection with an LCD mask, and 3) transparent OLED display with an LCD mask. Large format (80" diagonal) and dual layer volumetric variations are also implemented.

  4. The Sensitivity of Coded Mask Telescopes

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald K.

    2008-01-01

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

  5. An interactive tool for gamut masking

    NASA Astrophysics Data System (ADS)

    Song, Ying; Lau, Cheryl; Süsstrunk, Sabine

    2014-02-01

    Artists often want to change the colors of an image to achieve a particular aesthetic goal. For example, they might limit colors to a warm or cool color scheme to create an image with a certain mood or feeling. Gamut masking is a technique that artists use to limit the set of colors they can paint with. They draw a mask over a color wheel and only use the hues within the mask. However, creating the color palette from the mask and applying the colors to the image requires skill. We propose an interactive tool for gamut masking that allows amateur artists to create an image with a desired mood or feeling. Our system extracts a 3D color gamut from the 2D user-drawn mask and maps the image to this gamut. The user can draw a different gamut mask or locally refine the image colors. Our voxel grid gamut representation allows us to represent gamuts of any shape, and our cluster-based image representation allows the user to change colors locally.

  6. Reflective masks for extreme ultraviolet lithography

    SciTech Connect

    Nguyen, Khanh Bao

    1994-05-01

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

  7. Intact crowding and temporal masking in dyslexia.

    PubMed

    Doron, Adi; Manassi, Mauro; Herzog, Michael H; Ahissar, Merav

    2015-01-01

    Phonological deficits in dyslexia are well documented. However, there is an ongoing discussion about whether visual deficits limit the reading skills of people with dyslexia. Here, we investigated visual crowding and backward masking. We presented a Vernier (i.e., two vertical bars slightly offset to the left or right) and asked observers to indicate the offset direction. Vernier stimuli are visually similar to letters and are strongly affected by crowding, even in the fovea. To increase task difficulty, Verniers are often followed by a mask (i.e., backward masking). We measured Vernier offset discrimination thresholds for the basic Vernier task, under crowding, and under backward masking, in students with dyslexia (n = 19) and age and intelligence matched students (n = 27). We found no group differences in any of these conditions. Controls with fast visual processing (good backward masking performance), were faster readers. By contrast, no such correlation was found among the students with dyslexia, suggesting that backward masking does not limit their reading efficiency. These findings indicate that neither elevated crowding nor elevated backward masking pose a bottleneck to reading skills of people with dyslexia. PMID:26505966

  8. Space and time in masking and crowding.

    PubMed

    Lev, Maria; Polat, Uri

    2015-01-01

    Masking and crowding are major phenomena associated with contextual modulations, but the relationship between them remains unclear. We have recently shown that crowding is apparent in the fovea when the time available for processing is limited, pointing to the strong relationship between crowding in the spatial and temporal domains. Models of crowding emphasize the size (acuity) of the target and the spacing between the target and flankers as the main determinants that predict crowding. Our model, which is based on lateral interactions, posits that masking and crowding are related in the spatial and temporal domains at the fovea and periphery and that both can be explained by the increasing size of the human perceptive field (PF) with increasing eccentricity. We explored the relations between masking and crowding using letter identification and contrast detection by correlating the crowding effect with the estimated size of the PF and with masking under different spatiotemporal conditions. We found that there is a large variability in PF size and crowding effects across observers. Nevertheless, masking and crowding were both correlated with the estimated size of the PF in the fovea and periphery under a specific range of spatiotemporal parameters. Our results suggest that under certain conditions, crowding and masking share common neural mechanisms that underlie the spatiotemporal properties of these phenomena in both the fovea and periphery. These results could explain the transfer of training gains from spatiotemporal Gabor masking to letter acuity, reading, and reduced crowding.

  9. Intact crowding and temporal masking in dyslexia.

    PubMed

    Doron, Adi; Manassi, Mauro; Herzog, Michael H; Ahissar, Merav

    2015-01-01

    Phonological deficits in dyslexia are well documented. However, there is an ongoing discussion about whether visual deficits limit the reading skills of people with dyslexia. Here, we investigated visual crowding and backward masking. We presented a Vernier (i.e., two vertical bars slightly offset to the left or right) and asked observers to indicate the offset direction. Vernier stimuli are visually similar to letters and are strongly affected by crowding, even in the fovea. To increase task difficulty, Verniers are often followed by a mask (i.e., backward masking). We measured Vernier offset discrimination thresholds for the basic Vernier task, under crowding, and under backward masking, in students with dyslexia (n = 19) and age and intelligence matched students (n = 27). We found no group differences in any of these conditions. Controls with fast visual processing (good backward masking performance), were faster readers. By contrast, no such correlation was found among the students with dyslexia, suggesting that backward masking does not limit their reading efficiency. These findings indicate that neither elevated crowding nor elevated backward masking pose a bottleneck to reading skills of people with dyslexia.

  10. Emulation of anamorphic imaging on the SHARP EUV mask microscope

    NASA Astrophysics Data System (ADS)

    Benk, Markus P.; Wojdyla, Antoine; Chao, Weilun; Salmassi, Farhad; Oh, Sharon; Wang, Yow-Gwo; Miyakawa, Ryan H.; Naulleau, Patrick P.; Goldberg, Kenneth A.

    2016-03-01

    The SHARP High numerical aperture Actinic Reticle review Project is a synchrotron-based, extreme ultraviolet (EUV) microscope dedicated to photomask research. SHARP emulates the illumination and imaging conditions of current EUV lithography scanners and several generations into the future. An anamorphic imaging optic with increased mask side-NA in the horizontal and increased demagnification in the vertical direction has been proposed to overcome limitations of current multilayer coatings and extend EUV lithography beyond 0.33 NA.1 Zoneplate lenses with an anamorphic 4x/8x NA of 0.55 are fabricated and installed in the SHARP microscope to emulate anamorphic imaging. SHARP's Fourier synthesis illuminator with a range of angles exceeding the collected solid angle of the newly designed elliptical zoneplates can produce arbitrary angular source spectra, matched to anamorphic imaging. A target with anamorphic dense features down to 50-nm critical dimension is fabricated using 40-nm of nickel as the absorber. In a demonstration experiment anamorphic imaging at 0.55 4x/8xNA and 6° central ray angle is compared to conventional imaging at 0.5 4xNA and 8° central ray angle. A significant contrast loss in horizontal features is observed in the conventional images. The anamorphic images show the same image quality in the horizontal and vertical directions.

  11. A binary masking technique for isolating energetic masking in speech perception

    NASA Astrophysics Data System (ADS)

    Brungart, Douglas S.; Simpson, Brian D.; Chang, Peter S.; Wang, Deliang

    2005-04-01

    When a target speech signal is obscured by interfering speech, two distinct types of masking contribute to the resulting degradation in the intelligibility of the target talker: energetic masking caused by overlap in the time-frequency distribution of energy in the two voices, and informational masking caused by the listener's inability to correctly segregate the acoustic elements of the two voices into distinct streams. This study attempted to isolate the effects of energetic masking on multitalker speech perception with ideal time-frequency binary masks that retained those spectro-temporal regions of the acoustic mixture that were dominated by the target speech but eliminated those regions that were dominated by the interfering speech. This procedure removed the same phonetic information from the target speech that would ordinarily be lost due to energetic masking, but eliminated the possibility for the kinds of target-masker confusions that are thought to produce informational masking. The results suggest that energetic masking may play a surprisingly small role in the overall masking that occurs in certain types of multitalker speech signals. They also indicate that the number of competing talkers has a much greater influence than target-masker similarity on the amount of energetic masking that occurs in a multitalker stimulus.

  12. The actin cytoskeleton as a sensor and mediator of apoptosis

    PubMed Central

    Desouza, Melissa; Gunning, Peter W.; Stehn, Justine R.

    2012-01-01

    Apoptosis is an important biological process required for the removal of unwanted or damaged cells. Mounting evidence implicates the actin cytoskeleton as both a sensor and mediator of apoptosis. Studies also suggest that actin binding proteins (ABPs) significantly contribute to apoptosis and that actin dynamics play a key role in regulating apoptosis signaling. Changes in the organization of the actin cytoskeleton has been attributed to the process of malignant transformation and it is hypothesized that remodeling of the actin cytoskeleton may enable tumor cells to evade normal apoptotic signaling. This review aims to illuminate the role of the actin cytoskeleton in apoptosis by systematically analyzing how actin and ABPs regulate different apoptosis pathways and to also highlight the potential for developing novel compounds that target tumor-specific actin filaments. PMID:22880146

  13. CNS myelin wrapping is driven by actin disassembly.

    PubMed

    Zuchero, J Bradley; Fu, Meng-Meng; Sloan, Steven A; Ibrahim, Adiljan; Olson, Andrew; Zaremba, Anita; Dugas, Jason C; Wienbar, Sophia; Caprariello, Andrew V; Kantor, Christopher; Leonoudakis, Dmitri; Leonoudakus, Dmitri; Lariosa-Willingham, Karen; Kronenberg, Golo; Gertz, Karen; Soderling, Scott H; Miller, Robert H; Barres, Ben A

    2015-07-27

    Myelin is essential in vertebrates for the rapid propagation of action potentials, but the molecular mechanisms driving its formation remain largely unknown. Here we show that the initial stage of process extension and axon ensheathment by oligodendrocytes requires dynamic actin filament assembly by the Arp2/3 complex. Unexpectedly, subsequent myelin wrapping coincides with the upregulation of actin disassembly proteins and rapid disassembly of the oligodendrocyte actin cytoskeleton and does not require Arp2/3. Inducing loss of actin filaments drives oligodendrocyte membrane spreading and myelin wrapping in vivo, and the actin disassembly factor gelsolin is required for normal wrapping. We show that myelin basic protein, a protein essential for CNS myelin wrapping whose role has been unclear, is required for actin disassembly, and its loss phenocopies loss of actin disassembly proteins. Together, these findings provide insight into the molecular mechanism of myelin wrapping and identify it as an actin-independent form of mammalian cell motility.

  14. Actin network architecture can determine myosin motor activity.

    PubMed

    Reymann, Anne-Cécile; Boujemaa-Paterski, Rajaa; Martiel, Jean-Louis; Guérin, Christophe; Cao, Wenxiang; Chin, Harvey F; De La Cruz, Enrique M; Théry, Manuel; Blanchoin, Laurent

    2012-06-01

    The organization of actin filaments into higher-ordered structures governs eukaryotic cell shape and movement. Global actin network size and architecture are maintained in a dynamic steady state through regulated assembly and disassembly. Here, we used experimentally defined actin structures in vitro to investigate how the activity of myosin motors depends on network architecture. Direct visualization of filaments revealed myosin-induced actin network deformation. During this reorganization, myosins selectively contracted and disassembled antiparallel actin structures, while parallel actin bundles remained unaffected. The local distribution of nucleation sites and the resulting orientation of actin filaments appeared to regulate the scalability of the contraction process. This "orientation selection" mechanism for selective contraction and disassembly suggests how the dynamics of the cellular actin cytoskeleton can be spatially controlled by actomyosin contractility.

  15. Printed shadow masks for organic transistors

    NASA Astrophysics Data System (ADS)

    Noguchi, Yoshiaki; Sekitani, Tsuyoshi; Someya, Takao

    2007-09-01

    We have manufactured organic field-effect transistors by using shadow masks that are patterned by a screen printing system. The 50-nm-thick pentacene layer is sublimed as a channel in the vacuum system through the shadow mask on the base film with a multilayer patterned by ink-jet. After the deposition of the pentacene layer, the shadow mask is peeled off from the base film without any mechanical damages to the lower structures. The mobility in the saturation regime is 0.4cm2/Vs and the on-off ratio exceeds 105.

  16. Evaluation and implementation of TeraScan reflected light die-to-database inspection mode for 65nm design node process

    NASA Astrophysics Data System (ADS)

    Hsu, Luke T. H.; Ho, C. H.; Lin, C. C.; Hsu, Vincent; Chen, Ellison; Yu, Paul; Son, Kong

    2005-11-01

    The standard inspection flow typically consists of transmitted light pattern inspection (die-to-die or die-to-database) and STARlightTM (Simultaneous Transmitted And Reflective Light) contamination inspection. The initial introduction of TeraScan (DUV) inspection system was limited to transmitted pattern inspection modes. Hence, complete inspections of critical mask layers required utilizing TeraScan for maximized pattern defect sensitivity and the previous generation TeraStar (UV) for STARlightTM contamination inspection. Recently, the reflective light die-to-database (dbR) inspection mode was introduced on the DUV tool to compliment transmitted light die-to-database (dbT) inspection. The dbR inspection mode provides not only pattern inspection but also contamination inspection capabilities. The intent of this evaluation is to characterize the dbR inspection capability on pattern defects and contaminations. A series of standard programmed defect test plates will be used to evaluate pattern inspection capability and a PSL test plate will be used to determine the contamination performance. Inspection results will be compared to the current inspection process of record (dbT + STARlightTM). Lastly, the learning will be used to develop and implement an optimal dbR inspection flow for selected critical layers of the 65-nm node to meet the inspection criteria and minimize the cycle time.

  17. Utilization of paramagnetic relaxation enhancements for structural analysis of actin-binding proteins in complex with actin

    PubMed Central

    Huang, Shuxian; Umemoto, Ryo; Tamura, Yuki; Kofuku, Yutaka; Uyeda, Taro Q. P.; Nishida, Noritaka; Shimada, Ichio

    2016-01-01

    Actin cytoskeleton dynamics are controlled by various actin binding proteins (ABPs) that modulate the polymerization of the monomeric G-actin and the depolymerization of filamentous F-actin. Although revealing the structures of the actin/ABP complexes is crucial to understand how the ABPs regulate actin dynamics, the X-ray crystallography and cryoEM methods are inadequate to apply for the ABPs that interact with G- or F-actin with lower affinity or multiple binding modes. In this study, we aimed to establish the alternative method to build a structural model of G-actin/ABP complexes, utilizing the paramagnetic relaxation enhancement (PRE) experiments. Thymosin β4 (Tβ4) was used as a test case for validation, since its structure in complex with G-actin was reported recently. Recombinantly expressed G-actin, containing a cysteine mutation, was conjugated with a nitroxyl spin label at the specific site. Based on the intensity ratio of the 1H-15N HSQC spectra of Tβ4 in the complex with G-actin in the paramagnetic and diamagnetic states, the distances between the amide groups of Tβ4 and the spin label of G-actin were estimated. Using the PRE-derived distance constraints, we were able to compute a well-converged docking structure of the G-actin/Tβ4 complex that shows great accordance with the reference structure. PMID:27654858

  18. When Bad Masks Turn Good

    NASA Astrophysics Data System (ADS)

    Abraham, Roberto G.

    In keeping with the spirit of a meeting on ‘masks,' this talk presents two short stories on the theme of dust. In the first, dust plays the familiar role of the evil obscurer, the enemy to bedefeated by the cunning observer in order to allow a key future technology (adaptive optics) to be exploited fully by heroic astronomers. In the second story, dust itself emerges as the improbable hero, in the form of a circumstellar debris disks. I will present evidence of a puzzling near-infrared excess in the continuum of high-redshift galaxies and will argue that the seemingly improbable origin of this IR excess is a population of young circumstellar disks formed around high-mass stars in distant galaxies. Assuming circumstellar disks extend down to lower masses,as they do in our own Galaxy, the excess emission presents us with an exciting opportunity to measure the formation rate of planetary systems in distant galaxies at cosmic epochs before our own solar system formed.

  19. High temperature reactive ion etching of iridium thin films with aluminum mask in CF4/O2/Ar plasma

    NASA Astrophysics Data System (ADS)

    Yeh, Chia-Pin; Lisker, Marco; Kalkofen, Bodo; Burte, Edmund P.

    2016-08-01

    Reactive ion etching (RIE) technology for iridium with CF4/O2/Ar gas mixtures and aluminum mask at high temperatures up to 350 °C was developed. The influence of various process parameters such as gas mixing ratio and substrate temperature on the etch rate was studied in order to find optimal process conditions. The surface of the samples after etching was found to be clean under SEM inspection. It was also shown that the etch rate of iridium could be enhanced at higher process temperature and, at the same time, very high etching selectivity between aluminum etching mask and iridium could be achieved.

  20. Interaction of profilin with the barbed end of actin filaments.

    PubMed

    Courtemanche, Naomi; Pollard, Thomas D

    2013-09-17

    Profilin binds not only to actin monomers but also to the barbed end of the actin filament, where it inhibits association of subunits. To address open questions about the interactions of profilin with barbed ends, we measured the effects of a wide range of concentrations of Homo sapiens profilin 1 on the rate of elongation of individual skeletal muscle actin filaments by total internal reflection fluorescence microscopy. Much higher concentrations of profilin were required to stop elongation by AMP-PNP-actin monomers than ADP-actin monomers. High concentrations of profilin depolymerized barbed ends at a rate much faster than the spontaneous dissociation rates of Mg-ATP-, Mg-AMP-PNP-, Mg-ADP-Pi-, and Mg-ADP-actin subunits. Fitting a thermodynamic model to these data allowed us to determine the affinities of profilin and profilin-actin for barbed ends and the influence of the nucleotide bound to actin on these interactions. Profilin has a much higher affinity for ADP-actin filament barbed ends (Kd = 1 μM) than AMP-PNP-actin filament barbed ends (Kd = 226 μM). ADP-actin monomers associated with profilin bind to ADP-actin filament barbed ends 10% as fast as free ADP-actin monomers, but bound profilin does not affect the rate of association of AMP-PNP-actin monomers with barbed ends. The differences in the affinities of AMP-PNP- and ADP-bound barbed ends for profilin and profilin-actin suggest that conformations of barbed end subunits differ from those of monomers and change upon nucleotide hydrolysis and phosphate release. A structural model revealed minor steric clashes between profilin and actin subunits at the barbed end that explain the biochemical results.

  1. Actin of Beta vulgaris seedlings under the clinorotation

    NASA Astrophysics Data System (ADS)

    Kozeko, L. Ye.

    We study the influence of altered gravity on actin expression in roots of Beta vulguris seedlings grown on the horizontal clinostat (2 rpm) from seed germination for three days. It is shown that the total actin quantity was not influenced. Three actin isoforms are revealed; a relative protein quantity of these isoforms was similar both in clinorotated seedlings and in ones grown in norm. This point to stable expression of actin under the altered gravity conditions.

  2. Curvature and torsion in growing actin networks

    NASA Astrophysics Data System (ADS)

    Shaevitz, Joshua W.; Fletcher, Daniel A.

    2008-06-01

    Intracellular pathogens such as Listeria monocytogenes and Rickettsia rickettsii move within a host cell by polymerizing a comet-tail of actin fibers that ultimately pushes the cell forward. This dense network of cross-linked actin polymers typically exhibits a striking curvature that causes bacteria to move in gently looping paths. Theoretically, tail curvature has been linked to details of motility by considering force and torque balances from a finite number of polymerizing filaments. Here we track beads coated with a prokaryotic activator of actin polymerization in three dimensions to directly quantify the curvature and torsion of bead motility paths. We find that bead paths are more likely to have low rather than high curvature at any given time. Furthermore, path curvature changes very slowly in time, with an autocorrelation decay time of 200 s. Paths with a small radius of curvature, therefore, remain so for an extended period resulting in loops when confined to two dimensions. When allowed to explore a three-dimensional (3D) space, path loops are less evident. Finally, we quantify the torsion in the bead paths and show that beads do not exhibit a significant left- or right-handed bias to their motion in 3D. These results suggest that paths of actin-propelled objects may be attributed to slow changes in curvature, possibly associated with filament debranching, rather than a fixed torque.

  3. Viscoelastic properties of actin-coated membranes

    NASA Astrophysics Data System (ADS)

    Helfer, E.; Harlepp, S.; Bourdieu, L.; Robert, J.; Mackintosh, F. C.; Chatenay, D.

    2001-02-01

    In living cells, cytoskeletal filaments interact with the plasma membrane to form structures that play a key role in cell shape and mechanical properties. To study the interaction between these basic components, we designed an in vitro self-assembled network of actin filaments attached to the outer surface of giant unilamellar vesicles. Optical tweezers and single-particle tracking experiments are used to study the rich dynamics of these actin-coated membranes (ACM). We show that microrheology studies can be carried out on such an individual microscopic object. The principle of the experiment consists in measuring the thermally excited position fluctuations of a probe bead attached biochemically to the membrane. We propose a model that relates the power spectrum of these thermal fluctuations to the viscoelastic properties of the membrane. The presence of the actin network modifies strongly the membrane dynamics with respect to a fluid, lipid bilayer one. It induces first a finite (ω=0) two-dimensional (2D) shear modulus G02D~0.5 to 5 μN/m in the membrane plane. Moreover, the frequency dependence at high frequency of the shear modulus [G'2D(f )~f0.85+/-0.07] and of the bending modulus (κACM(f)~f0.55+/-0.21) demonstrate the viscoelastic behavior of the composite membrane. These results are consistent with a common exponent of 0.75 for both moduli as expected from our model and from prior measurements on actin solutions.

  4. Investigation of EUV haze defect: molecular behaviors of mask cleaning chemicals on EUV mask surfaces

    NASA Astrophysics Data System (ADS)

    Choi, Jaehyuck; Novak, Steve; Kandel, Yudhishthir; Denbeaux, Greg; Lee, Han-shin; Ma, Andy; Goodwin, Frank

    2012-03-01

    Photo-induced defects (or haze defects) on 193nm optic masks (haze defects) have been a serious problem not only to reticle engineers working for mask manufacturing and handling but also to photo-lithography engineers. The most widely accepted explanation of the root causes of haze defects is the cleaning chemical residues remaining on the mask surface and unavoidable outgassed molecules that outgas from pellicle materials when exposed to 193nm radiation. These have been significant challenges for reticle cleaning engineers who need to use cleaning chemicals whose residues do not lead to progressive defect formation on the mask and to find improved materials to minimize pellicle outgassing. It is assumed that contamination generation on EUV masks would have a higher probability than on optic masks, primarily since EUV masks are not protected by a pellicle and amorphous carbon films can accumulate during exposure to EUV light. While there is potential to mitigate the generation of carbon contamination by improving the exposure tool environment and removing carbon films using in-situ atomic hydrogen cleaning, it is not yet clear whether the reaction of mask cleaning chemicals to EUV radiation will lead to creation of progressive defects on EUV mask surfaces. With the work to being done it has been observed that carbon contamination on EUV masks dominates any effects of solvent chemicals under normal environmental or exposure conditions (from atmospheric pressure up to a vacuum level of 10-6 Torr) during EUV exposure. However, it is still unknown whether residual cleaning chemicals will provide a nucleus for progressive defect formation during exposure. This lack of understanding needs to be addressed by the industry as EUV masks are expected to undergo more frequent cleaning cycles. In this work, we will report on an investigation of the molecular behavior of cleaning chemicals on EUV mask surfaces during EUV exposure. Movement (e.g., migration or aggregation) of

  5. Endothelial actin-binding proteins and actin dynamics in leukocyte transendothelial migration.

    PubMed

    Schnoor, Michael

    2015-04-15

    The endothelium is the first barrier that leukocytes have to overcome during recruitment to sites of inflamed tissues. The leukocyte extravasation cascade is a complex multistep process that requires the activation of various adhesion molecules and signaling pathways, as well as actin remodeling, in both leukocytes and endothelial cells. Endothelial adhesion molecules, such as E-selectin or ICAM-1, are connected to the actin cytoskeleton via actin-binding proteins (ABPs). Although the contribution of receptor-ligand interactions to leukocyte extravasation has been studied extensively, the contribution of endothelial ABPs to the regulation of leukocyte adhesion and transendothelial migration remains poorly understood. This review focuses on recently published evidence that endothelial ABPs, such as cortactin, myosin, or α-actinin, regulate leukocyte extravasation by controlling actin dynamics, biomechanical properties of endothelia, and signaling pathways, such as GTPase activation, during inflammation. Thus, ABPs may serve as targets for novel treatment strategies for disorders characterized by excessive leukocyte recruitment.

  6. Competition of two distinct actin networks for actin defines a bistable switch for cell polarization

    PubMed Central

    Lomakin, Alexis J.; Lee, Kun-Chun; Han, Sangyoon J.; Bui, D A.; Davidson, Michael; Mogilner, Alex; Danuser, Gaudenz

    2015-01-01

    Symmetry-breaking polarization enables functional plasticity of cells and tissues and is yet not well understood. Here we show that epithelial cells, hard-wired to maintain a static morphology and to preserve tissue organization, can spontaneously switch to a migratory polarized phenotype upon relaxation of the actomyosin cytoskeleton. We find that myosin-II engages actin in the formation of cortical actomyosin bundles and thus makes it unavailable for deployment in the process of dendritic growth normally driving cell motility. At low contractility regimes epithelial cells polarize in a front-back manner due to emergence of actin retrograde flows powered by dendritic polymerization of actin. Coupled to cell movement, the flows transport myosin-II from the front to the back of the cell, where the motor locally “locks” actin in contractile bundles. This polarization mechanism could be employed by embryonic and cancer epithelial cells in microenvironments where high contractility-driven cell motion is inefficient. PMID:26414403

  7. Actin cytoskeleton demonstration in Trichomonas vaginalis and in other trichomonads.

    PubMed

    Brugerolle, G; Bricheux, G; Coffe, G

    1996-01-01

    The flagellate form of Trichomonas vaginalis (T v) transforms to amoeboid cells upon adherence to converslips. They grow and their nuclei divide without undergoing cytokinesis, yielding giant cells and a monolayer of T v F-actin was demonstrated in Trichomonas vaginalis by fluorescence microscopy using phalloidin and an anti-actin mAb which labelled the cytoplasm of both the flagellate and amoeboid forms. Comparative electrophoresis and immunoblotting established that the actin band has the same 42 kDa as muscle actin, but 2-D electrophoresis resolved the actin band into four spots; the two major spots observed were superimposable with major muscle actin isoforms. Electron microscopy demonstrated an ectoplasmic microfibrillar layer along the adhesion zone of amoeboid T v adhering to coverslips. Immunogold staining, using anti-actin monoclonal antibodies demonstrated that this layer was mainly composed of actin microfilaments. A comparative immunoblotting study comprising seven trichomonad species showed that all trichomonads studied expressed actin. The mAb Sigma A-4700 specific for an epitope on the actin C-terminal sequence labelled only actin of Trichomonas vaginalis, Tetratrichomonas gallinarum. Trichomitus batrachorum and Hypotrichomonas acosta, but not the actin of Tritrichomonas foetus, Tritrichomonas augusta and Monocercomonas sp. This discrimination between a 'trichomonas branch' and a 'tritrichomonas branch' is congruent with inferred sequence phylogeny from SSu rRNA and with classical phylogeny of trichomonads. PMID:9175265

  8. Actin-organising properties of the muscular dystrophy protein myotilin.

    PubMed

    von Nandelstadh, Pernilla; Grönholm, Mikaela; Moza, Monica; Lamberg, Arja; Savilahti, Harri; Carpén, Olli

    2005-10-15

    Myotilin is a sarcomeric Z-disc protein that binds F-actin directly and bundles actin filaments, although it does not contain a conventional actin-binding domain. Expression of mutant myotilin leads to sarcomeric alterations in the dominantly inherited limb-girdle muscular dystrophy 1A and in myofibrillar myopathy/desmin-related myopathy. Together, with previous in vitro studies, this indicates that myotilin has an important function in the assembly and maintenance of Z-discs. This study characterises further the interaction between myotilin and actin. Functionally important regions in myotilin were identified by actin pull-down and yeast two-hybrid assays and with a novel strategy that combines in vitro DNA transposition-based peptide insertion mutagenesis with phenotype analysis in yeast cells. The shortest fragment to bind actin was the second Ig domain together with a short C-terminal sequence. Concerted action of the first and second Ig domain was, however, necessary for the functional activity of myotilin, as verified by analysis of transposon mutants, actin binding and phenotypic effect in mammalian cells. Furthermore, the Ig domains flanked with N- and C-terminal regions were needed for actin-bundling, indicating that the mere actin-binding sequence was insufficient for the actin-regulating activity. None of the four known disease-associated mutations altered the actin-organising ability. These results, together with previous studies in titin and kettin, identify the Ig domain as an actin-binding unit.

  9. Prostaglandins temporally regulate cytoplasmic actin bundle formation during Drosophila oogenesis.

    PubMed

    Spracklen, Andrew J; Kelpsch, Daniel J; Chen, Xiang; Spracklen, Cassandra N; Tootle, Tina L

    2014-02-01

    Prostaglandins (PGs)--lipid signals produced downstream of cyclooxygenase (COX) enzymes--regulate actin dynamics in cell culture and platelets, but their roles during development are largely unknown. Here we define a new role for Pxt, the Drosophila COX-like enzyme, in regulating the actin cytoskeleton--temporal restriction of actin remodeling during oogenesis. PGs are required for actin filament bundle formation during stage 10B (S10B). In addition, loss of Pxt results in extensive early actin remodeling, including actin filaments and aggregates, within the posterior nurse cells of S9 follicles; wild-type follicles exhibit similar structures at a low frequency. Hu li tai shao (Hts-RC) and Villin (Quail), an actin bundler, localize to all early actin structures, whereas Enabled (Ena), an actin elongation factor, preferentially localizes to those in pxt mutants. Reduced Ena levels strongly suppress early actin remodeling in pxt mutants. Furthermore, loss of Pxt results in reduced Ena localization to the sites of bundle formation during S10B. Together these data lead to a model in which PGs temporally regulate actin remodeling during Drosophila oogenesis by controlling Ena localization/activity, such that in S9, PG signaling inhibits, whereas at S10B, it promotes Ena-dependent actin remodeling.

  10. Shape control of lipid bilayer membranes by confined actin bundles.

    PubMed

    Tsai, Feng-Ching; Koenderink, Gijsje Hendrika

    2015-12-01

    In living cells, lipid membranes and biopolymers determine each other's conformation in a delicate force balance. Cellular polymers such as actin filaments are strongly confined by the plasma membrane in cell protrusions such as lamellipodia and filopodia. Conversely, protrusion formation is facilitated by actin-driven membrane deformation and these protrusions are maintained by dense actin networks or bundles of actin filaments. Here we investigate the mechanical interplay between actin bundles and lipid bilayer membranes by reconstituting a minimal model system based on cell-sized liposomes with encapsulated actin filaments bundled by fascin. To address the competition between the deformability of the membrane and the enclosed actin bundles, we tune the bundle stiffness (through the fascin-to-actin molar ratio) and the membrane rigidity (through protein decoration). Using confocal microscopy and quantitative image analysis, we show that actin bundles deform the liposomes into a rich set of morphologies. For liposomes having a small membrane bending rigidity, the actin bundles tend to generate finger-like membrane protrusions that resemble cellular filopodia. Stiffer bundles formed at high crosslink density stay straight in the liposome body, whereas softer bundles formed at low crosslink density are bent and kinked. When the membrane has a large bending rigidity, membrane protrusions are suppressed. In this case, membrane enclosure forces the actin bundles to organize into cortical rings, to minimize the energy cost associated with filament bending. Our results highlight the importance of taking into account mechanical interactions between the actin cytoskeleton and the membrane to understand cell shape control.

  11. Unconventional actins and actin-binding proteins in human protozoan parasites.

    PubMed

    Gupta, C M; Thiyagarajan, S; Sahasrabuddhe, A A

    2015-06-01

    Actin and its regulatory proteins play a key role in several essential cellular processes such as cell movement, intracellular trafficking and cytokinesis in most eukaryotes. While these proteins are highly conserved in higher eukaryotes, a number of unicellular eukaryotic organisms contain divergent forms of these proteins which have highly unusual biochemical and structural properties. Here, we review the biochemical and structural properties of these unconventional actins and their core binding proteins which are present in commonly occurring human protozoan parasites.

  12. 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.

  13. Shadow-masked growth and its applications

    NASA Astrophysics Data System (ADS)

    Demeester, Piet M. A.; Coudenys, G.; Vermeire, Gerrit; Moerman, Ingrid; Zhu, Youcai; Buydens, Luc; Eeckhout, C.; Van Daele, Peter

    1993-02-01

    In this paper we will review the shadow masked growth technique and its applications. The technique enables us to change the layer thicknesses over a substrate by the variation in dimensions of windows in the shadow mask. One of the major application areas is the realization of photonic integrated circuits where materials with a different bandgap have to be integrated on the same substrate. The combination of thickness variations with the use of quantum wells results in the required bandgap changes. In the paper we will first start with an overview of the basic technology of shadow masked growth and in a second part we will discuss some of the important applications. Note that we will limit ourselves to the shadow masked growth technique and no review will be given on other technologies such as selective growth.

  14. Simplified models for mask roughness induced LER

    SciTech Connect

    McClinton, Brittany; Naulleau, Patrick

    2011-02-21

    The ITRS requires < 1.2nm line-edge roughness (LER) for the 22nm half-pitch node. Currently, we can consistently achieve only about 3nm LER. Further progress requires understanding the principle causes of LER. Much work has already been done on how both the resist and LER on the mask effect the final printed LER. What is poorly understood, however, is the extent to which system-level effects such as mask surface roughness, illumination conditions, and defocus couple to speckle at the image plane, and factor into LER limits. Presently, mask-roughness induced LER is studied via full 2D aerial image modeling and subsequent analysis of the resulting image. This method is time consuming and cumbersome. It is, therefore, the goal of this research to develop a useful 'rule-of-thumb' analytic model for mask roughness induced LER to expedite learning and understanding.

  15. Optical fiber inspection system

    DOEpatents

    Moore, F.W.

    1985-04-05

    A remote optical inspection system including an inspection head. The inspection head has a passageway through which pellets or other objects are passed. A window is provided along the passageway through which light is beamed against the objects being inspected. A plurality of lens assemblies are arranged about the window so that reflected light can be gathered and transferred to a plurality of coherent optical fiber light guides. The light guides transfer the light images to a television or other image transducer which converts the optical images into a representative electronic signal. The electronic signal can then be displayed on a signal viewer such as a television monitor for inspection by a person. A staging means can be used to support the objects for viewing through the window. Routing means can be used to direct inspected objects into appropriate exit passages for accepted or rejected objects. The inspected objects are advantageously fed in a singular manner to the staging means and routing means. The inspection system is advantageously used in an enclosure when toxic or hazardous materials are being inspected. 10 figs.

  16. Optical fiber inspection system

    DOEpatents

    Moore, Francis W.

    1987-01-01

    A remote optical inspection system including an inspection head. The inspection head has a passageway through which pellets or other objects are passed. A window is provided along the passageway through which light is beamed against the objects being inspected. A plurality of lens assemblies are arranged about the window so that reflected light can be gathered and transferred to a plurality of coherent optical fiber light guides. The light guides transfer the light images to a television or other image transducer which converts the optical images into a representative electronic signal. The electronic signal can then be displayed on a signal viewer such as a television monitor for inspection by a person. A staging means can be used to support the objects for viewing through the window. Routing means can be used to direct inspected objects into appropriate exit passages for accepted or rejected objects. The inspected objects are advantageously fed in a singular manner to the staging means and routing means. The inspection system is advantageously used in an enclosure when toxic or hazardous materials are being inspected.

  17. FMNL3 FH2-actin structure gives insight into formin-mediated actin nucleation and elongation

    SciTech Connect

    Thompson, Morgan E; Heimsath, Ernest G; Gauvin, Timothy J; Higgs, Henry N; Kull, F Jon

    2012-12-09

    Formins are actin-assembly factors that act in a variety of actin-based processes. The conserved formin homology 2 (FH2) domain promotes filament nucleation and influences elongation through interaction with the barbed end. FMNL3 is a formin that induces assembly of filopodia but whose FH2 domain is a poor nucleator. The 3.4-Å structure of a mouse FMNL3 FH2 dimer in complex with tetramethylrhodamine-actin uncovers details of formin-regulated actin elongation. We observe distinct FH2 actin-binding regions; interactions in the knob and coiled-coil subdomains are necessary for actin binding, whereas those in the lasso-post interface are important for the stepping mechanism. Biochemical and cellular experiments test the importance of individual residues for function. This structure provides details for FH2-mediated filament elongation by processive capping and supports a model in which C-terminal non-FH2 residues of FMNL3 are required to stabilize the filament nucleus.

  18. The neural processing of masked speech.

    PubMed

    Scott, Sophie K; McGettigan, Carolyn

    2013-09-01

    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. This article is part of a Special Issue entitled "Annual Reviews 2013". PMID:23685149

  19. 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.

  20. VSP wave separation by adaptive masking filters

    NASA Astrophysics Data System (ADS)

    Rao, Ying; Wang, Yanghua

    2016-06-01

    In vertical seismic profiling (VSP) data processing, the first step might be to separate the down-going wavefield from the up-going wavefield. When using a masking filter for VSP wave separation, there are difficulties associated with two termination ends of the up-going waves. A critical challenge is how the masking filter can restore the energy tails, the edge effect associated with these terminations uniquely exist in VSP data. An effective strategy is to implement masking filters in both τ-p and f-k domain sequentially. Meanwhile it uses a median filter, producing a clean but smooth version of the down-going wavefield, used as a reference data set for designing the masking filter. The masking filter is implemented adaptively and iteratively, gradually restoring the energy tails cut-out by any surgical mute. While the τ-p and the f-k domain masking filters target different depth ranges of VSP, this combination strategy can accurately perform in wave separation from field VSP data.

  1. Structure of a Bud6/actin complex reveals a novel WH2-like actin monomer recruitment motif

    PubMed Central

    Park, Eunyoung; Graziano, Brian R.; Zheng, Wei; Garabedian, Mikael; Goode, Bruce L.; Eck, Michael J.

    2015-01-01

    SUMMARY In budding yeast, the actin-binding protein Bud6 cooperates with formins Bni1 and Bnr1 to catalyze the assembly of actin filaments. The nucleation-enhancing activity of Bud6 requires both a “core” domain that binds to the formin and a “flank” domain that binds monomeric actin. Here we describe the structure of the Bud6 flank domain in complex with actin. Two helices in Bud6flank interact with actin; one binds in a groove at the barbed-end of the actin monomer in a manner closely resembling the helix of WH2 domains, a motif found in many actin nucleation factors. The second helix rises along the face of actin. Mutational analysis verifies the importance of these Bud6-actin contacts for nucleation-enhancing activity. The Bud6 binding site on actin overlaps with that of the formin FH2 domain and is also incompatible with inter-subunit contacts in F-actin, suggesting that Bud6 interacts only transiently with actin monomers during filament nucleation. PMID:26118535

  2. Structure of a Bud6/Actin Complex Reveals a Novel WH2-like Actin Monomer Recruitment Motif.

    PubMed

    Park, Eunyoung; Graziano, Brian R; Zheng, Wei; Garabedian, Mikael; Goode, Bruce L; Eck, Michael J

    2015-08-01

    In budding yeast, the actin-binding protein Bud6 cooperates with formins Bni1 and Bnr1 to catalyze the assembly of actin filaments. The nucleation-enhancing activity of Bud6 requires both a "core" domain that binds to the formin and a "flank" domain that binds monomeric actin. Here, we describe the structure of the Bud6 flank domain in complex with actin. Two helices in Bud6(flank) interact with actin; one binds in a groove at the barbed end of the actin monomer in a manner closely resembling the helix of WH2 domains, a motif found in many actin nucleation factors. The second helix rises along the face of actin. Mutational analysis verifies the importance of these Bud6-actin contacts for nucleation-enhancing activity. The Bud6 binding site on actin overlaps with that of the formin FH2 domain and is also incompatible with inter-subunit contacts in F-actin, suggesting that Bud6 interacts only transiently with actin monomers during filament nucleation.

  3. The origin and evolution of green algal and plant actins.

    PubMed

    An, S S; Möpps, B; Weber, K; Bhattacharya, D

    1999-02-01

    The Viridiplantae are subdivided into two groups: the Chlorophyta, which includes the Chlorophyceae, Trebouxiophyceae, Ulvophyceae, and Prasinophyceae; and the Streptophyta, which includes the Charophyceae and all land plants. Within the Streptophyta, the actin genes of the angiosperms diverge nearly simultaneously from each other before the separation of monocots and dicots. Previous evolutionary analyses have provided limited insights into the gene duplications that have produced these complex gene families. We address the origin and diversification of land plant actin genes by studying the phylogeny of actins within the green algae, ferns, and fern allies. Partial genomic sequences or cDNAs encoding actin were characterized from Cosmarium botrytis (Zygnematales), Selaginella apoda (Selaginellales), Anemia phyllitidis (Polypodiales), and Psilotum triquetrum (Psilotales). Selaginella contains at least two actin genes. One sequence (Ac2) diverges within a group of fern sequences that also includes the Psilotum Ac1 actin gene and one gymnosperm sequence (Cycas revoluta Cyc3). This clade is positioned outside of the angiosperm actin gene radiation. The second Selaginella sequence (Ac1) is the sister to all remaining land plant actin sequences, although the internal branches in this portion of the tree are very short. Use of complete actin-coding regions in phylogenetic analyses provides support for the separation of angiosperm actins into two classes. N-terminal "signature" sequence analyses support these groupings. One class (VEG) includes actin genes that are often expressed in vegetative structures. The second class (REP) includes actin genes that trace their ancestry within the vegetative actins and contains members that are largely expressed in reproductive structures. Analysis of intron positions within actin genes shows that sequences from both Selaginella and Cosmarium contain the conserved 20-3, 152-1, and 356-3 introns found in many members of the

  4. Demonstration of prominent actin filaments in the root columella.

    PubMed

    Collings, D A; Zsuppan, G; Allen, N S; Blancaflor, E B

    2001-02-01

    The distribution of actin filaments within the gravity-sensing columella cells of plant roots remains poorly understood, with studies over numerous years providing inconsistent descriptions of actin organization in these cells. This uncertainty in actin organization, and thus in actin's role in graviperception and gravisignaling, has led us to investigate actin arrangements in the columella cells of Zea mays L., Medicago truncatula Gaertn., Linum usitatissiilium L. and Nicotianla benthamiana Domin. Actin organization was examined using a combination of optimized immunofluorescence techniques, and an improved fluorochrome-conjugated phalloidin labeling method reliant on 3-maleimidobenzoyl-N-hydroxy-succinimide ester (MBS) cross-linking combined with glycerol permeabilization. Confocal microscopy of root sections labeled with anti-actin antibodies revealed patterns suggestive of actin throughout the columella region. These patterns included short and fragmented actin bundles, fluorescent rings around amyloplasts and intense fluorescence originating from the nucleus. Additionally, confocal microscopy of MBS-stabilized and Alexa Fluor-phalloidin-labeled root sections revealed a previously undetected state of actin organization in the columella. Discrete actin structures surrounded the amyloplasts and prominent actin cables radiated from the nuclear surface toward the cell periphery. Furthermore, the cortex of the columella cells contained fine actin bundles (or single filaments) that had a predominant transverse orientation. We also used confocal microscopy of plant roots expressing endoplasmic reticulum (ER)-targeted green fluorescent protein to demonstrate rapid ER movements within the columella cells, suggesting that the imaged actin network is functional. The successful identification of discrete actin structures in the root columella cells forms the perception and signaling. PMID:11289604

  5. Exploring the Stability Limits of Actin and Its Suprastructures

    PubMed Central

    Rosin, Christopher; Erlkamp, Mirko; Ecken, Julian von der; Raunser, Stefan; Winter, Roland

    2014-01-01

    Actin is the main component of the microfilament system in eukaryotic cells and can be found in distinct morphological states. Global (G)-actin is able to assemble into highly organized, supramolecular cellular structures known as filamentous (F)-actin and bundled (B)-actin. To evaluate the structure and stability of G-, F-, and B-actin over a wide range of temperatures and pressures, we used Fourier transform infrared spectroscopy in combination with differential scanning and pressure perturbation calorimetry, small-angle x-ray scattering, laser confocal scanning microscopy, and transmission electron microscopy. Our analysis was designed to provide new (to our knowledge) insights into the stabilizing forces of actin self-assembly and to reveal the stability of the actin polymorphs, including in conditions encountered in extreme environments. In addition, we sought to explain the limited pressure stability of actin self-assembly observed in vivo. G-actin is not only the least temperature-stable but also the least pressure-stable actin species. Under abyssal conditions, where temperatures as low as 1–4°C and pressures up to 1 kbar are reached, G-actin is hardly stable. However, the supramolecular assemblies of actin are stable enough to withstand the extreme conditions usually encountered on Earth. Beyond ∼3–4 kbar, filamentous structures disassemble, and beyond ∼4 kbar, complete dissociation of F-actin structures is observed. Between ∼1 and 2 kbar, some disordering of actin assemblies commences, in agreement with in vivo observations. The limited pressure stability of the monomeric building block seems to be responsible for the suppression of actin assembly in the kbar pressure range. PMID:25517163

  6. Demonstration of prominent actin filaments in the root columella

    NASA Technical Reports Server (NTRS)

    Collings, D. A.; Zsuppan, G.; Allen, N. S.; Blancaflor, E. B.; Brown, C. S. (Principal Investigator)

    2001-01-01

    The distribution of actin filaments within the gravity-sensing columella cells of plant roots remains poorly understood, with studies over numerous years providing inconsistent descriptions of actin organization in these cells. This uncertainty in actin organization, and thus in actin's role in graviperception and gravisignaling, has led us to investigate actin arrangements in the columella cells of Zea mays L., Medicago truncatula Gaertn., Linum usitatissiilium L. and Nicotianla benthamiana Domin. Actin organization was examined using a combination of optimized immunofluorescence techniques, and an improved fluorochrome-conjugated phalloidin labeling method reliant on 3-maleimidobenzoyl-N-hydroxy-succinimide ester (MBS) cross-linking combined with glycerol permeabilization. Confocal microscopy of root sections labeled with anti-actin antibodies revealed patterns suggestive of actin throughout the columella region. These patterns included short and fragmented actin bundles, fluorescent rings around amyloplasts and intense fluorescence originating from the nucleus. Additionally, confocal microscopy of MBS-stabilized and Alexa Fluor-phalloidin-labeled root sections revealed a previously undetected state of actin organization in the columella. Discrete actin structures surrounded the amyloplasts and prominent actin cables radiated from the nuclear surface toward the cell periphery. Furthermore, the cortex of the columella cells contained fine actin bundles (or single filaments) that had a predominant transverse orientation. We also used confocal microscopy of plant roots expressing endoplasmic reticulum (ER)-targeted green fluorescent protein to demonstrate rapid ER movements within the columella cells, suggesting that the imaged actin network is functional. The successful identification of discrete actin structures in the root columella cells forms the perception and signaling.

  7. 21 CFR 868.5560 - Gas mask head strap.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gas mask head strap. 868.5560 Section 868.5560...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5560 Gas mask head strap. (a) Identification. A gas mask head strap is a device used to hold an anesthetic gas mask in position on a...

  8. 21 CFR 868.5560 - Gas mask head strap.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas mask head strap. 868.5560 Section 868.5560...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5560 Gas mask head strap. (a) Identification. A gas mask head strap is a device used to hold an anesthetic gas mask in position on a...

  9. 21 CFR 868.5560 - Gas mask head strap.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gas mask head strap. 868.5560 Section 868.5560...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5560 Gas mask head strap. (a) Identification. A gas mask head strap is a device used to hold an anesthetic gas mask in position on a...

  10. 42 CFR 84.111 - Gas masks; required components.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Gas masks; required components. 84.111 Section 84... AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.111 Gas masks; required components. (a) Each gas mask described in § 84.110 shall, where its...

  11. 42 CFR 84.111 - Gas masks; required components.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Gas masks; required components. 84.111 Section 84... AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.111 Gas masks; required components. (a) Each gas mask described in § 84.110 shall, where its...

  12. 42 CFR 84.111 - Gas masks; required components.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Gas masks; required components. 84.111 Section 84... AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.111 Gas masks; required components. (a) Each gas mask described in § 84.110 shall, where its...

  13. Ceramic Masks--A Multi-Cultural Experience

    ERIC Educational Resources Information Center

    Penn, Elizabeth E.

    1978-01-01

    The creation of ceramic masks in reaction to the film, Roots, focused on the functions of the masks themselves within a particular society, the materials and techniques used to create these masks, and the identification of typical shapes of heads and facial features on the masks in each culture. (Author/RK)

  14. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Mask work fees. 211.3 Section... PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask works. (b)...

  15. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Mask work fees. 211.3 Section... PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask works. (b)...

  16. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Mask work fees. 211.3 Section... PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask works. (b)...

  17. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Mask work fees. 211.3 Section... AND PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask...

  18. 37 CFR 211.3 - Mask work fees.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Mask work fees. 211.3 Section... PROCEDURES MASK WORK PROTECTION § 211.3 Mask work fees. (a) Section 201.3 of this chapter prescribes the fees or charges established by the Register of Copyrights for services relating to mask works. (b)...

  19. Actin nucleation and elongation factors: mechanisms and interplay.

    PubMed

    Chesarone, Melissa A; Goode, Bruce L

    2009-02-01

    Cells require actin nucleators to catalyze the de novo assembly of filaments and actin elongation factors to control the rate and extent of polymerization. Nucleation and elongation factors identified to date include Arp2/3 complex, formins, Ena/VASP, and newcomers Spire, Cobl, and Lmod. Here, we discuss recent advances in understanding their activities and mechanisms and new evidence for their cooperation and interaction in vivo. Earlier models had suggested that different nucleators function independently to assemble distinct actin arrays. However, more recent observations indicate that the construction of most cellular actin networks depends on the activities of multiple actin assembly-promoting factors working in concert.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  1. Best-practice evaluation-methods for wafer-fab photomask-requalification inspection tools

    NASA Astrophysics Data System (ADS)

    Cho, Chan Seob; Mungmode, Ashish; Taylor, Ron; Cho, David; Koh, Hui Peng

    2014-10-01

    Requalifying semiconductor photomasks remains critically important and is increasingly challenging for 20nm and 14nm node logic reticles. Patterns are becoming more complex on the photomask, and defect sensitivity requirements are more stringent than ever before. Reticle inspection tools are equally important for effective process development and the successful ramp and sustained yield for high volume manufacturing. The inspection stages considered were: incoming inspection to match with Mask Shop Outgoing result and to detect defects generated during transport; requalification by routine cycle inspection to detect Haze and any other defects; and inspection by in-house or Mask shop at the post cleaning. There are many critical capability and capacity factors for the decision for best inspection tool and strategy for high volume manufacturing, especially objective Lens NA, wavelength, power, pixel size, throughput, full-automation inspection linked with Overhead Transport, algorithm application, engineering application function, and inspection of PSM and OMOG . These tools are expensive but deliver differentiated value in terms of performance and throughput as well as extendibility. Performing a thorough evaluation and making a technically sound choice which explores these many factors is critical for success of a fab. This paper examines the methodology for evaluating two different photomask inspection tools. The focus is on ensuring production worthiness on real and advanced product photomasks requiring accurate evaluation of sensitivity, throughput, data analysis function and engineering work function on those product photomasks. Photomasks used for data collection are production reticles, PDM(Program defect Mask), SiN spray defect Reticle which is described that evaluates how the tools would perform on a contaminated plate.

  2. Mask topography effect in chromeless phase lithography

    NASA Astrophysics Data System (ADS)

    Philipsen, Vicky; Bekaert, Joost; Vandenberghe, Geert; Jonckheere, Rik; Van Den Broeke, Douglas; Socha, Robert

    2004-12-01

    Different types of phase-shift masks (PSM) in combination with the proper illumination condition are widely used to allow 193nm lithography to print ever-decreasing pitches with a sufficient process window. A viable option for the 65nm node is Chromeless Phase Lithography (CPL), which combines a chromeless phase shift mask and 193nm off-axis illumination. It has been demonstrated that CPL has a high flexibility for through pitch imaging. Also concerning mask making CPL masks showed advantages over alternating and attenuated PSM [1]. This paper discusses how the mask quality and its topography influence the imaging performance of CPL. It is shown that mask topography is an important factor for CPL, as the imaging relies also on the quartz depth differences in the mask. The wafer image is sensitive to phase variations induced by the quartz etch depth and the sidewall profile. Their impact is separately studied using rigorous 3D mask electro-magnetic field simulations (Sigma-C Solid-CM). Correlation of experimental results to simulation explains that the observed pitch-dependent tilt in the Bossung curves is mainly related to the 3D character of the mask. In search for a global compensation valid through pitch, the simulation study also evaluates the effect of other contributors such as lens aberrations in the optical system, assist features and half-toning Cr zebra lines in the design. However, as the tilt is inherent to the CPL mask fabrication, a compensation of the Bossung tilt effect can only be obtained for specific combinations of all sources, as will be shown. We concentrate on the imaging of 70nm lines and 100nm contact holes in pitches ranging from dense up to isolated. The wafers are exposed on an ASML PAS5500/1100 ArF scanner working with a 0.75NA projection lens and various types of off-axis illumination. The wafers are evaluated on a top-down CD SEM (KLA-Tencor 8250XR).

  3. Fire Prevention Inspection Procedures.

    ERIC Educational Resources Information Center

    Pribyl, Paul F.

    Lesson plans are provided for a fire prevention inspection course of the Wisconsin Fire Service Training program. Objectives for the course are to enable students to describe and conduct fire prevention inspections, to identify and correct hazards common to most occupancies, to understand the types of building construction and occupancy, and to…

  4. Inspection information model

    SciTech Connect

    Bradford, J.

    1989-12-01

    This document establishes information structures and semantics used for the electronic communication of Product Definition Data (PDD) which supports dimensional inspection using contact Coordinate Measuring Machines (CMM). Included are attributes of CMMs for support of generative process planning functions for dimensional inspection.

  5. Direct Observation of Tropomyosin Binding to Actin Filaments

    PubMed Central

    Schmidt, William M.; Lehman, William; Moore, Jeffrey R.

    2015-01-01

    Tropomyosin is an elongated α-helical coiled-coil that binds to seven consecutive actin subunits along the long-pitch helix of actin filaments. Once bound, tropomyosin polymerizes end-to-end and both stabilizes F-actin and regulates access of various actin binding proteins including myosin in muscle and non-muscle cells. Single tropomyosin molecules bind weakly to F-actin with millimolar Kd, whereas the end-to-end linked tropomyosin associates with about a one thousand-fold greater affinity. Despite years of study, the assembly mechanism of tropomyosin onto actin filaments remains unclear. In the current study, we used total internal reflection fluorescence (TIRF) microscopy to directly monitor the cooperative binding of fluorescently labeled tropomyosin molecules to phalloidin-stabilized actin filaments. We find that tropomyosin molecules assemble from multiple growth sites following random low affinity binding of single molecules to actin. As the length of the tropomyosin chain increases, the probability of detachment decreases, which leads to further chain growth. Tropomyosin chain extension is linearly dependent on tropomyosin concentration, occurring at approximately 100 monomers/(μM*s). The random tropomyosin binding to F-actin leads to discontinuous end-to-end association where gaps in the chain continuity smaller than the required seven sequential actin monomers are available. Direct observation of tropomyosin detachment revealed the number of gaps in actin-bound tropomyosin, the time course of gap annealing, and the eventual filament saturation process. PMID:26033920

  6. Actin in xenopus oocytes: II. intracellular distribution and polymerizability

    PubMed Central

    Merriam, RW; Clark, TG

    1978-01-01

    The largest oocytes of Xenopus Laevis were broken open in the absence of shearing forces which might transfer actin from particulate to supernatant fractions. Particulate and postmitochondrial supernatant fractions were prepared by centrifugation. SDS-electrophoretic fractionation on polyacrylamide gels and quantitative scanning techniques were used to separate actin and to assay its amount in cellular fractions. The actin has been identified in electrophoretograms by its molecular weight and its binding to DNase I. oocytes contain 1.4-1.7 {um}g of actin per cell, of which up to 88 percent is recovered in the postmitochondrial supernate under a variety of conditions. In the soluble fraction, it represents about 8.8 percent of the total protein. Its concentration in native cytoplasm was directly assayed at 4.1 mg/ml. There is no detectable actin that can be transferred from the particulate to the soluble phase by neutral detergents or ionic conditions that would depolymerize muscle actin. Centrifugation of the soluble oocyte fractions showed that 75-95 percent of the actin can not be sedimented under forces that would pellet filamentous actin. Addition of potassium and magnesium to the cytoplasm, to concentrations that would polymerize muscle actin, does not increase the amount of sedimentable actin. Roughly one-third of the soluble actin is recovered from Sephadex columns at about the position of monomer. About two- thirds is in complexes of 100,000 daltons or greater. PMID:565782

  7. Distributed actin turnover in the lamellipodium and FRAP kinetics.

    PubMed

    Smith, Matthew B; Kiuchi, Tai; Watanabe, Naoki; Vavylonis, Dimitrios

    2013-01-01

    Studies of actin dynamics at the leading edge of motile cells with single-molecule speckle (SiMS) microscopy have shown a broad distribution of EGFP-actin speckle lifetimes and indicated actin polymerization and depolymerization over an extended region. Other experiments using FRAP with the same EGFP-actin as a probe have suggested, by contrast, that polymerization occurs exclusively at the leading edge. We performed FRAP experiments on XTC cells to compare SiMS to FRAP on the same cell type. We used speckle statistics obtained by SiMS to model the steady-state distribution and kinetics of actin in the lamellipodium. We demonstrate that a model with a single diffuse actin species is in good agreement with FRAP experiments. A model including two species of diffuse actin provides an even better agreement. The second species consists of slowly diffusing oligomers that associate to the F-actin network throughout the lamellipodium or break up into monomers after a characteristic time. Our work motivates studies to test the presence and composition of slowly diffusing actin species that may contribute to local remodeling of the actin network and increase the amount of soluble actin.

  8. Bundling actin filaments from membranes: some novel players

    PubMed Central

    Thomas, Clément

    2012-01-01

    Progress in live-cell imaging of the cytoskeleton has significantly extended our knowledge about the organization and dynamics of actin filaments near the plasma membrane of plant cells. Noticeably, two populations of filamentous structures can be distinguished. On the one hand, fine actin filaments which exhibit an extremely dynamic behavior basically characterized by fast polymerization and prolific severing events, a process referred to as actin stochastic dynamics. On the other hand, thick actin bundles which are composed of several filaments and which are comparatively more stable although they constantly remodel as well. There is evidence that the actin cytoskeleton plays critical roles in trafficking and signaling at both the cell cortex and organelle periphery but the exact contribution of actin bundles remains unclear. A common view is that actin bundles provide the long-distance tracks used by myosin motors to deliver their cargo to growing regions and accordingly play a particularly important role in cell polarization. However, several studies support that actin bundles are more than simple passive highways and display multiple and dynamic roles in the regulation of many processes, such as cell elongation, polar auxin transport, stomatal and chloroplast movement, and defense against pathogens. The list of identified plant actin-bundling proteins is ever expanding, supporting that plant cells shape structurally and functionally different actin bundles. Here I review the most recently characterized actin-bundling proteins, with a particular focus on those potentially relevant to membrane trafficking and/or signaling. PMID:22936939

  9. A second Las17 monomeric actin-binding motif functions in Arp2/3-dependent actin polymerization during endocytosis.

    PubMed

    Feliciano, Daniel; Tolsma, Thomas O; Farrell, Kristen B; Aradi, Al; Di Pietro, Santiago M

    2015-04-01

    During clathrin-mediated endocytosis (CME), actin assembly provides force to drive vesicle internalization. Members of the Wiskott-Aldrich syndrome protein (WASP) family play a fundamental role stimulating actin assembly. WASP family proteins contain a WH2 motif that binds globular actin (G-actin) and a central-acidic motif that binds the Arp2/3 complex, thus promoting the formation of branched actin filaments. Yeast WASP (Las17) is the strongest of five factors promoting Arp2/3-dependent actin polymerization during CME. It was suggested that this strong activity may be caused by a putative second G-actin-binding motif in Las17. Here, we describe the in vitro and in vivo characterization of such Las17 G-actin-binding motif (LGM) and its dependence on a group of conserved arginine residues. Using the yeast two-hybrid system, GST-pulldown, fluorescence polarization and pyrene-actin polymerization assays, we show that LGM binds G-actin and is necessary for normal Arp2/3-mediated actin polymerization in vitro. Live-cell fluorescence microscopy experiments demonstrate that LGM is required for normal dynamics of actin polymerization during CME. Further, LGM is necessary for normal dynamics of endocytic machinery components that are recruited at early, intermediate and late stages of endocytosis, as well as for optimal endocytosis of native CME cargo. Both in vitro and in vivo experiments show that LGM has relatively lower potency compared to the previously known Las17 G-actin-binding motif, WH2. These results establish a second G-actin-binding motif in Las17 and advance our knowledge on the mechanism of actin assembly during CME.

  10. The Potential Roles of Actin in The Nucleus

    PubMed Central

    Falahzadeh, Khadijeh; Banaei-Esfahani, Amir; Shahhoseini, Maryam

    2015-01-01

    Over the past few decades, actin’s presence in the nucleus has been demonstrated. Actin is a key protein necessary for different nuclear processes. Although actin is well known for its functional role in dynamic behavior of the cytoskeleton, emerging studies are now highlighting new roles for actin. At the present time there is no doubt about the presence of actin in the nucleus. A number of studies have uncovered the functional involvement of actin in nuclear processes. Actin as one of the nuclear components has its own structured and functional rules, such as nuclear matrix association, chromatin remodeling, transcription by RNA polymerases I, II, III and mRNA processing. In this historical review, we attempt to provide an overview of our current understanding of the functions of actin in the nucleus. PMID:25870830

  11. Regulation of cellular actin architecture by S100A10.

    PubMed

    Jung, M Juliane; Murzik, Ulrike; Wehder, Liane; Hemmerich, Peter; Melle, Christian

    2010-04-15

    Actin structures are involved in several biological processes and the disruption of actin polymerisation induces impaired motility of eukaryotic cells. Different factors are involved in regulation and maintenance of the cytoskeletal actin architecture. Here we show that S100A10 participates in the particular organisation of actin filaments. Down-regulation of S100A10 by specific siRNA triggered a disorganisation of filamentous actin structures without a reduction of the total cellular actin concentration. In contrast, the formation of cytoskeleton structures containing tubulin was unhindered in S100A10 depleted cells. Interestingly, the cellular distribution of annexin A2, an interaction partner of S100A10, was unaffected in S100A10 depleted cells. Cells lacking S100A10 showed an impaired migration activity and were unable to close a scratched wound. Our data provide first insights of S100A10 function as a regulator of the filamentous actin network. PMID:20100475

  12. Ligand-induced Epitope Masking

    PubMed Central

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

    2016-01-01

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

  13. Phase analysis of amplitude binary mask structures

    NASA Astrophysics Data System (ADS)

    Puthankovilakam, Krishnaparvathy; Scharf, Toralf; Herzig, Hans Peter; Vogler, Uwe; Bramati, Arianna; Voelkel, Reinhard

    2016-03-01

    Shaping of light behind masks using different techniques is the milestone of the printing industry. The aerial image distribution or the intensity distribution at the printing distances defines the resolution of the structure after printing. Contrast and phase are the two parameters that play a major role in shaping of light to get the desired intensity pattern. Here, in contrast to many other contributions that focus on intensity, we discuss the phase evolution for different structures. The amplitude or intensity characteristics of the structures in a binary mask at different proximity gaps have been analyzed extensively for many industrial applications. But the phase evolution from the binary mask having OPC structures is not considered so far. The mask we consider here is the normal amplitude binary mask but having high resolution Optical Proximity Correction (OPC) structures for corners. The corner structures represent a two dimensional problem which is difficult to handle with simple rules of phase masks design and therefore of particular interest. The evolution of light from small amplitude structures might lead to high contrast by creating sharp phase changes or phase singularities which are points of zero intensity. We show the phase modulation at different proximity gaps and can visualize the shaping of light according to the phase changes. The analysis is done with an instrument called High Resolution Interference Microscopy (HRIM), a Mach-Zehnder interferometer that gives access to three-dimensional phase and amplitude images. The current paper emphasizes on the phase measurement of different optical proximity correction structures, and especially on corners of a binary mask.

  14. Unconscious processing of dichoptically masked words.

    PubMed

    Greenwald, A G; Klinger, M R; Liu, T J

    1989-01-01

    In three experiments, the subjects' task was to decide whether each of a series of words connoted something good (e.g., fame, comedy, rescue) or bad (stress, detest, malaria). One-half second before the presentation of each such target word, an evaluatively polarized priming word was presented briefly to the nondominant eye and was masked dichoptically by either the rapidly following (Experiment 1) or simultaneous (Experiments 2 and 3) presentation of a random letter-fragment pattern to the dominant eye. (The effectiveness of the masking procedure was demonstrated by the subjects' inability to discriminate the left vs. right position of a test series of words.) In all experiments, significant masked priming effects were obtained; evaluative decisions to congruent masked prime-target combinations (such as a positive masked prime followed by a positive target) were significantly faster than those to incongruent (e.g., negative prime/positive target) or noncongruent (e.g., neutral prime/positive target) combinations. Also, in two of the three experiments, when subjects were at chance accuracy in discriminating word position, their position judgments were nevertheless significantly influenced by the irrelevant semantic content (LEFT vs. RIGHT) of the masked position-varying words. The series of experiments demonstrated that two very different tasks--speeded judgment of evaluative meaning and nonspeeded judgment of word position--yielded statistically significant and replicable influences of the semantic content of apparently undetectable words. Coupled with previous research by others using the lexical decision task, these findings converge in establishing the reliability of the empirical phenomenon of semantic processing of words that are rendered undetectable by dichoptic pattern masking.

  15. Partial Depletion of Gamma-Actin Suppresses Microtubule Dynamics

    PubMed Central

    Po'uha, Sela T; Honore, Stephane; Braguer, Diane; Kavallaris, Maria

    2013-01-01

    Actin and microtubule interactions are important for many cellular events, however these interactions are poorly described. Alterations in γ-actin are associated with diseases such as hearing loss and cancer. Functional investigations demonstrated that partial depletion of γ-actin affects cell polarity and induces resistance to microtubule-targeted agents. To determine whether γ-actin alterations directly affect microtubule dynamics, microtubule dynamic instability was analyzed in living cells following partial siRNA depletion of γ-actin. Partial depletion of γ-actin suppresses interphase microtubule dynamics by 17.5% due to a decrease in microtubule shortening rates and an increase in microtubule attenuation. γ-Actin partial depletion also increased distance-based microtubule catastrophe and rescue frequencies. In addition, knockdown of γ-actin delayed mitotic progression, partially blocking metaphase–anaphase transition and inhibiting cell proliferation. Interestingly, in the presence of paclitaxel, interphase microtubule dynamics were further suppressed by 24.4% in the γ-actin knockdown cells, which is comparable to 28.8% suppression observed in the control siRNA treated cells. Paclitaxel blocked metaphase–anaphase transition in both the γ-actin knockdown cells and the control siRNA cells. However, the extent of mitotic arrest was much higher in the control cells (28.4%), compared to the γ-actin depleted cells (8.5%). Therefore, suppression of microtubule dynamics by partial depletion of γ-actin is associated with marked delays in metaphase-anaphase transition and not mitotic arrest. This is the first demonstration that γ-actin can modulate microtubule dynamics by reducing the microtubule shortening rate, promoting paused/attenuated microtubules, and increasing transition frequencies suggesting a mechanistic link between γ-actin and microtubules. © 2013 Wiley Periodicals, Inc PMID:23335583

  16. Distinct Functional Interactions between Actin Isoforms and Nonsarcomeric Myosins

    PubMed Central

    Müller, Mirco; Diensthuber, Ralph P.; Chizhov, Igor; Claus, Peter; Heissler, Sarah M.; Preller, Matthias; Taft, Manuel H.; Manstein, Dietmar J.

    2013-01-01

    Despite their near sequence identity, actin isoforms cannot completely replace each other in vivo and show marked differences in their tissue-specific and subcellular localization. Little is known about isoform-specific differences in their interactions with myosin motors and other actin-binding proteins. Mammalian cytoplasmic β- and γ-actin interact with nonsarcomeric conventional myosins such as the members of the nonmuscle myosin-2 family and myosin-7A. These interactions support a wide range of cellular processes including cytokinesis, maintenance of cell polarity, cell adhesion, migration, and mechano-electrical transduction. To elucidate differences in the ability of isoactins to bind and stimulate the enzymatic activity of individual myosin isoforms, we characterized the interactions of human skeletal muscle α-actin, cytoplasmic β-actin, and cytoplasmic γ-actin with human myosin-7A and nonmuscle myosins-2A, -2B and -2C1. In the case of nonmuscle myosins-2A and -2B, the interaction with either cytoplasmic actin isoform results in 4-fold greater stimulation of myosin ATPase activity than was observed in the presence of α-skeletal muscle actin. Nonmuscle myosin-2C1 is most potently activated by β-actin and myosin-7A by γ-actin. Our results indicate that β- and γ-actin isoforms contribute to the modulation of nonmuscle myosin-2 and myosin-7A activity and thereby to the spatial and temporal regulation of cytoskeletal dynamics. FRET-based analyses show efficient copolymerization abilities for the actin isoforms in vitro. Experiments with hybrid actin filaments show that the extent of actomyosin coupling efficiency can be regulated by the isoform composition of actin filaments. PMID:23923011

  17. Reconstitution and Protein Composition Analysis of Endocytic Actin Patches

    PubMed Central

    Michelot, Alphée; Costanzo, Michael; Sarkeshik, Ali; Boone, Charles; Yates, John R.; Drubin, David G.

    2010-01-01

    Summary Background Clathrin-actin-mediated endocytosis in yeast involves the progressive assembly of at least 60 different proteins at cortical sites. More than half of these proteins are involved in the assembly of a branched network of actin filaments to provide the forces required for plasma membrane invagination. Results To gain insights into the regulation of endocytic actin patch dynamics, we developed an in vitro actin assembly assay using microbeads functionalized with the nucleation promoting factor (NPF) Las17 (yeast WASP). When incubated in a yeast extract, these beads assembled actin networks and a significant fraction became motile. Multi dimensional Protein Identification Technology (MudPIT) showed that the recruitment of actin binding proteins to these Las17-derived actin networks is selective. None of the proteins known to exclusively regulate the in vivo formation of actin cables or the actin contractile ring were identified. Intriguingly, our analysis also identified components of three other cortical structures, eisosomes, PIK patches and the TORC2 complex, establishing intriguing biochemical connections between four different yeast cortical complexes. Finally, we identified Aim3 as a regulator of actin dynamics at endocytic sites. Conclusions WASP is sufficient to trigger assembly of actin networks composed selectively of actin-patch proteins. These experiments establish that the protein composition of different F-actin structures is determined by the protein factor that initiates the network. The identification of binding partners revealed new biochemical connections between WASP derived networks and other cortical complexes and identified Aim3 as a novel regulator of the endocytic actin patch. PMID:21035341

  18. Characterizing contamination inspection capabilities using programmed defect test reticles

    NASA Astrophysics Data System (ADS)

    Nhiev, Anthony; Riddick, John; Straub, Joseph; Hutchinson, Trent; Reese, Bryan; Dayal, Aditya

    2007-10-01

    The ORION TM series of test reticles have been used for many years as the photomask industry standard for evaluating contamination inspection algorithms. The deposition of Polystyrene Latex (PSL) spheres on various reticle pattern designs allow STARlight TM tool owners to measure the relative contamination inspection performance in a consistent and quantifiable manner. However, with recent inspection technology advances such as shorter laser (light source) wavelengths and smaller inspection pixels, PSL spheres were observed to physically degrade over relatively short time periods: especially for the smallest sized spheres used to characterize contamination inspection performance at the most advanced technology nodes. Investigations into using alternative materials or methods that address the issue of PSL shrinkage have not yet proven completely successful. Problems such as failure to properly adhere to reticle surfaces or identification of materials that can produce consistent and predictable sphere sizes for the reliable manufacture of these critical test masks are only some of the challenges that must be solved. Even if these and other criteria are met, the final substance must appear to inspection optics as pseudo soft defects which resemble actual contamination that inevitably appears on production reticle surfaces. In the interim, programmed pindot defects present in the quartz region of the SPICA TM test reticle are being used to characterize contamination performance while a suitable long-term solution to address the issue of shrinking PSL spheres on ORION masks can be found. This paper examines the results of a programmed pindot test reticle specifically designed to evaluate contamination algorithms without the deposition of PSL spheres or similar structures. This alternative programmed pindot test reticle uses various background patterns similar to the ORION, however, it also includes multiple defects sizes and locations making it more desirable than the

  19. Automated reticle inspection data analysis for wafer fabs

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

  20. Automated reticle inspection data analysis for wafer fabs

    NASA Astrophysics Data System (ADS)

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

    2008-10-01

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

  1. Automated reticle inspection data analysis for wafer fabs

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  2. The Intervenor Effect in Masked Priming: How Does Masked Priming Survive across an Intervening Word?

    ERIC Educational Resources Information Center

    Forster, Kenneth I.

    2009-01-01

    Four masked priming experiments are reported investigating the effect of inserting an unrelated word between the masked prime and the target. When the intervening word is visible, identity priming is reduced to the level of one-letter-different form priming, but form priming is largely unaffected. However, when the intervening word is itself…

  3. Caffeine relaxes smooth muscle through actin depolymerization.

    PubMed

    Tazzeo, Tracy; Bates, Genevieve; Roman, Horia Nicolae; Lauzon, Anne-Marie; Khasnis, Mukta D; Eto, Masumi; Janssen, Luke J

    2012-08-15

    Caffeine is sometimes used in cell physiological studies to release internally stored Ca(2+). We obtained evidence that caffeine may also act through a different mechanism that has not been previously described and sought to examine this in greater detail. We ruled out a role for phosphodiesterase (PDE) inhibition, since the effect was 1) not reversed by inhibiting PKA or adenylate cyclase; 2) not exacerbated by inhibiting PDE4; and 3) not mimicked by submillimolar caffeine nor theophylline, both of which are sufficient to inhibit PDE. Although caffeine is an agonist of bitter taste receptors, which in turn mediate bronchodilation, its relaxant effect was not mimicked by quinine. After permeabilizing the membrane using β-escin and depleting the internal Ca(2+) store using A23187, we found that 10 mM caffeine reversed tone evoked by direct application of Ca(2+), suggesting it functionally antagonizes the contractile apparatus. Using a variety of molecular techniques, we found that caffeine did not affect phosphorylation of myosin light chain (MLC) by MLC kinase, actin-filament motility catalyzed by MLC kinase, phosphorylation of CPI-17 by either protein kinase C or RhoA kinase, nor the activity of MLC-phosphatase. However, we did obtain evidence that caffeine decreased actin filament binding to phosphorylated myosin heads and increased the ratio of globular to filamentous actin in precontracted tissues. We conclude that, in addition to its other non-RyR targets, caffeine also interferes with actin function (decreased binding by myosin, possibly with depolymerization), an effect that should be borne in mind in studies using caffeine to probe excitation-contraction coupling in smooth muscle.

  4. Summertime actinic lichenoid eruption (lichen planus actinicus).

    PubMed

    Isaacson, D; Turner, M L; Elgart, M L

    1981-04-01

    A patient with an unusual lichenoid photosensitive eruption is presented. The features differentiating this entity from classic lichen planus, lupus erythematosus, and polymorphous light eruption are discussed. Phototesting confirmed the provocative influence of sunlight. We prefer the name "summertime actinic lichenoid eruption" to that of "lichen planus subtropicus" or "lichen planus actinicus," since this condition is not confined to subtropical countries, and, although light appears to initiate the eruption, its exact relationship to lichen planus is unclear.

  5. Viscoelastic properties of actin-coated membranes.

    PubMed

    Helfer, E; Harlepp, S; Bourdieu, L; Robert, J; MacKintosh, F C; Chatenay, D

    2001-02-01

    In living cells, cytoskeletal filaments interact with the plasma membrane to form structures that play a key role in cell shape and mechanical properties. To study the interaction between these basic components, we designed an in vitro self-assembled network of actin filaments attached to the outer surface of giant unilamellar vesicles. Optical tweezers and single-particle tracking experiments are used to study the rich dynamics of these actin-coated membranes (ACM). We show that microrheology studies can be carried out on such an individual microscopic object. The principle of the experiment consists in measuring the thermally excited position fluctuations of a probe bead attached biochemically to the membrane. We propose a model that relates the power spectrum of these thermal fluctuations to the viscoelastic properties of the membrane. The presence of the actin network modifies strongly the membrane dynamics with respect to a fluid, lipid bilayer one. It induces first a finite (omega=0) two-dimensional (2D) shear modulus G(0)(2D) approximately 0.5 to 5 microN/m in the membrane plane. Moreover, the frequency dependence at high frequency of the shear modulus [G(')(2D)(f ) approximately f(0.85+/-0.07)] and of the bending modulus (kappa(ACM)(f) approximately f(0.55+/-0.21)) demonstrate the viscoelastic behavior of the composite membrane. These results are consistent with a common exponent of 0.75 for both moduli as expected from our model and from prior measurements on actin solutions.

  6. Characterization and possible repair of defects in Soft X-ray Projection Lithography masks

    SciTech Connect

    Hawryluk, A.M.

    1993-07-01

    Soft X-ray Projection Lithography (SXPL) is one promising technique for the mass production of integrated circuits with minimum features sizes below 100 nm. Mask fabrication, inspection and repair processes are critically important to all forms of lithography, including SXPL which requires a reflection mask (a substrate coated with a x-ray multilayer coating and patterned with thin metallization layer). Processes for the repair of defects in the metallization patterns have been developed, but at present, there exist no processes for the repair of defects in the multilayer coatings deposited in LLNL`s magnetron sputter deposition facility, which produces state of the art x-ray multilayer mirrors. We also propose one possible process for the repair of defects in these multilayer coatings.

  7. Novel roles for actin in mitochondrial fission

    PubMed Central

    Hatch, Anna L.; Gurel, Pinar S.; Higgs, Henry N.

    2014-01-01

    ABSTRACT Mitochondrial dynamics, including fusion, fission and translocation, are crucial to cellular homeostasis, with roles in cellular polarity, stress response and apoptosis. Mitochondrial fission has received particular attention, owing to links with several neurodegenerative diseases. A central player in fission is the cytoplasmic dynamin-related GTPase Drp1, which oligomerizes at the fission site and hydrolyzes GTP to drive membrane ingression. Drp1 recruitment to the outer mitochondrial membrane (OMM) is a key regulatory event, which appears to require a pre-constriction step in which the endoplasmic reticulum (ER) and mitochondrion interact extensively, a process termed ERMD (ER-associated mitochondrial division). It is unclear how ER–mitochondrial contact generates the force required for pre-constriction or why pre-constriction leads to Drp1 recruitment. Recent results, however, show that ERMD might be an actin-based process in mammals that requires the ER-associated formin INF2 upstream of Drp1, and that myosin II and other actin-binding proteins might be involved. In this Commentary, we present a mechanistic model for mitochondrial fission in which actin and myosin contribute in two ways; firstly, by supplying the force for pre-constriction and secondly, by serving as a coincidence detector for Drp1 binding. In addition, we discuss the possibility that multiple fission mechanisms exist in mammals. PMID:25217628

  8. Virulent Burkholderia species mimic host actin polymerases to drive actin-based motility

    PubMed Central

    Benanti, Erin L.; Nguyen, Catherine M.; Welch, Matthew D.

    2015-01-01

    Summary Burkholderia pseudomallei and B. mallei are bacterial pathogens that cause melioidosis and glanders, while their close relative B. thailandensis is nonpathogenic. All use the trimeric autotransporter BimA to facilitate actin-based motility, host cell fusion and dissemination. Here, we show that BimA orthologs mimic different host actin-polymerizing proteins. B. thailandensis BimA activates the host Arp2/3 complex. In contrast, B. pseudomallei and B. mallei BimA mimic host Ena/VASP actin polymerases in their ability to nucleate, elongate and bundle filaments by associating with barbed ends, as well as in their use of WH2 motifs and oligomerization for activity. Mechanistic differences among BimA orthologs resulted in distinct actin filament organization and motility parameters, which affected the efficiency of cell fusion during infection. Our results identify bacterial Ena/VASP mimics and reveal that pathogens imitate the full spectrum of host actin-polymerizing pathways, suggesting that mimicry of different polymerization mechanisms influences key parameters of infection. PMID:25860613

  9. Virulent Burkholderia species mimic host actin polymerases to drive actin-based motility.

    PubMed

    Benanti, Erin L; Nguyen, Catherine M; Welch, Matthew D

    2015-04-01

    Burkholderia pseudomallei and B. mallei are bacterial pathogens that cause melioidosis and glanders, whereas their close relative B. thailandensis is non-pathogenic. All use the trimeric autotransporter BimA to facilitate actin-based motility, host cell fusion, and dissemination. Here, we show that BimA orthologs mimic different host actin-polymerizing proteins. B. thailandensis BimA activates the host Arp2/3 complex. In contrast, B. pseudomallei and B. mallei BimA mimic host Ena/VASP actin polymerases in their ability to nucleate, elongate, and bundle filaments by associating with barbed ends, as well as in their use of WH2 motifs and oligomerization for activity. Mechanistic differences among BimA orthologs resulted in distinct actin filament organization and motility parameters, which affected the efficiency of cell fusion during infection. Our results identify bacterial Ena/VASP mimics and reveal that pathogens imitate the full spectrum of host actin-polymerizing pathways, suggesting that mimicry of different polymerization mechanisms influences key parameters of infection.

  10. Lamellipodin promotes actin assembly by clustering Ena/VASP proteins and tethering them to actin filaments

    PubMed Central

    Hansen, Scott D; Mullins, R Dyche

    2015-01-01

    Enabled/Vasodilator (Ena/VASP) proteins promote actin filament assembly at multiple locations, including: leading edge membranes, focal adhesions, and the surface of intracellular pathogens. One important Ena/VASP regulator is the mig-10/Lamellipodin/RIAM family of adaptors that promote lamellipod formation in fibroblasts and drive neurite outgrowth and axon guidance in neurons. To better understand how MRL proteins promote actin network formation we studied the interactions between Lamellipodin (Lpd), actin, and VASP, both in vivo and in vitro. We find that Lpd binds directly to actin filaments and that this interaction regulates its subcellular localization and enhances its effect on VASP polymerase activity. We propose that Lpd delivers Ena/VASP proteins to growing barbed ends and increases their polymerase activity by tethering them to filaments. This interaction represents one more pathway by which growing actin filaments produce positive feedback to control localization and activity of proteins that regulate their assembly. DOI: http://dx.doi.org/10.7554/eLife.06585.001 PMID:26295568

  11. Dynacortin is a novel actin bundling protein that localizes to dynamic actin structures.

    PubMed

    Robinson, Douglas N; Ocon, Stephani S; Rock, Ronald S; Spudich, James A

    2002-03-15

    Dynacortin is a novel protein that was discovered in a genetic suppressor screen of a Dictyostelium discoideum cytokinesis-deficient mutant cell line devoid of the cleavage furrow actin bundling protein, cortexillin I. While dynacortin is highly enriched in the cortex, particularly in cell-surface protrusions, it is excluded from the cleavage furrow cortex during cytokinesis. Here, we describe the biochemical characterization of this new protein. Purified dynacortin is an 80-kDa dimer with a large 5.7-nm Stokes radius. Dynacortin cross-links actin filaments into parallel arrays with a mole ratio of one dimer to 1.3 actin monomers and a 3.1 microm K(d). Using total internal reflection fluorescence microscopy, GFP-dynacortin and the actin bundling protein coronin-GFP are seen to concentrate in highly dynamic cortical structures with assembly and disassembly half-lives of about 15 s. These results indicate that cells have evolved different actin-filament cross-linking proteins with complementary cellular distributions that collaborate to orchestrate complex cell shape changes.

  12. Mask and lithography techniques for FPD

    NASA Astrophysics Data System (ADS)

    Sandstrom, T.; Wahlsten, M.; Sundelin, E.; Hansson, G.; Svensson, A.

    2015-09-01

    Large-field projection lithography for FPDs has developed gradually since the 90s. The LCD screen technology has remained largely unchanged and incremental development has given us better image quality, larger screen sizes, and above all lower cost per area. Recently new types of mobile devices with very high pixel density and/or OLED displays have given rise to dramatically higher requirem ents on photomask technology. Devices with 600 ppi or m ore need lithography with higher optical resolution and better linewidth control. OLED di splays pose new challenges with high sensitivity to transistor parameters and to capacitive cross-talk. New mask requirements leads to new maskwriter requirements and Mycronic has developed a new generation of large -area mask writers with significantly improved properties. This paper discusses and shows data for the improved writers. Mask production to high er quality stan dards also need metrology to verify the quality and Mycronic has introduced a 2D metrology tool with accuracy adequate for current and future masks. New printing or additive methods of producing disp lays on plastic or metal foil will make low-cost disp lays available. This inexpensive type of disp lays will exist side by side with the photographic quality displays of TVs and mobile devices, which will continue to be a challenge in terms of mask and production quality.

  13. Calculating aerial images from EUV masks

    NASA Astrophysics Data System (ADS)

    Pistor, Thomas V.; Neureuther, Andrew R.

    1999-06-01

    Aerial images for line/space patterns, arrays of posts and an arbitrary layout pattern are calculated for EUV masks in a 4X EUV imaging system. Both mask parameters and illumination parameters are varied to investigate their effects on the aerial image. To facilitate this study, a parallel version of TEMPEST with a Fourier transform boundary condition was developed and run on a network of 24 microprocessors. Line width variations are observed when absorber thickness or sidewall angle changes. As the line/space pattern scales to smaller dimensions, the aspect ratios of the absorber features increase, introducing geometric shadowing and reducing aerial image intensity and contrast. 100nm square posts have circular images of diameter close to 100nm, but decreasing in diameter significantly when the corner round radius at the mask becomes greater than 50 nm. Exterior mask posts image slightly smaller and with higher ellipticity than interior mask posts. The aerial image of the arbitrary test pattern gives insight into the effects of the off-axis incidence employed in EUV lithography systems.

  14. Metrology on phase-shift masks

    NASA Astrophysics Data System (ADS)

    Roeth, Klaus-Dieter; Maurer, Wilhelm; Blaesing-Bangert, Carola

    1992-06-01

    In the evaluation of new manufacturing processes, metrology is a key function, beginning with the first step of process development through the final step of everyday mass production at the fabrication floor level. RIM-type phase shift masks are expected to be the first application of phase shift masks in high volume production, since they provide improved lithography process capability at the expense of only moderate complexity in their manufacturing. Measurements of critical dimension (CD) and pattern position (overlay) on experimental rim-type and chromeless phase shift masks are reported. Pattern placement (registration) was measured using the Leitz LMS 2000. The overall design and important components were already described. The pattern placement of the RIM type phase shift structures on the photomask described above was determined within a tolerance of 25 nm (3s); nominal accuracy was within 45 nm (3s). On the chromeless phase shift mask the measurement results were easily obtained using a wafer intensity algorithm available with the system. The measurement uncertainties were less than 25 nm and 50 nm for precision and nominal accuracy respectively. The measurement results from the Leitz CD 200 using transmitted light were: a CD- distribution of 135 nm (3s) on a typical 6 micrometers structure all over the mask; the 0.9 micrometers RIM structure had a distribution of 43 nm (3s). Typical long term precision performance values for the CD 200 on both chrome and phase shift structures have been less than 15 nm.

  15. Study of program defects of 22nm nanoimprint template with an advanced e-beam inspection system

    NASA Astrophysics Data System (ADS)

    Hiraka, Takaaki; Mizuochi, Jun; Nakanishi, Yuko; Yusa, Satoshi; Sasaki, Shiho; Kurihara, Masaaki; Toyama, Nobuhito; Morikawa, Yasutaka; Mohri, Hiroshi; Hayashi, Naoya; Xiao, Hong; Kuan, Chiyan; Wang, Fei; Ma, Long; Zhao, Yan; Jau, Jack

    2009-10-01

    Nanoimprint lithography (NIL) is a candidate of alternative, low cost of ownership lithography solution for deep nano-meter device manufacturing12. For the NIL template pattern making, we have been developing the processes with 100keV SB EB writer and 50keV VSB EB writer to achieve the fine resolution of near 20nm1-7. However, inspection of nanoimprint template posed a big challenge to inspection system due to the small geometry, 1x comparing to 4x of Optical mask and EUV mask. Previous studies of nanoimprint template inspection were performed indirectly on a stamped wafer and/or on a round quartz wafer13. Electron beam inspection (EBI) systems have been widely used in semiconductor fabs in nanometer technology nodes. Most commonly EBI applications are electrical defects, or voltage contrast (VC) defects detection and monitoring8-11. In this study, we used a mask EBI system developed by Hermes Microvision, Inc. (HMI) to directly inspect a NIL template with line/space and hole patterns half pitched from 22nm to 90nm and with program defects sized from 4nm to 92nm. Capability of inspection with 10nm pixel size has been demonstrated and capability of capturing program defects sized 12nm and smaller has been shown. This study proved the feasibility of EBI as inspection solution of nanoimprint template for 22nmHP and beyond.

  16. Computational Study of the Binding Mechanism of Actin-Depolymerizing Factor 1 with Actin in Arabidopsis thaliana

    PubMed Central

    Wang, Xue; Dong, Chun-Hai; Yang, Jian Ming; Yao, Xiao Jun

    2016-01-01

    Actin is a highly conserved protein. It plays important roles in cellular function and exists either in the monomeric (G-actin) or polymeric form (F-actin). Members of the actin-depolymerizing factor (ADF)/cofilin protein family bind to both G-actin and F-actin and play vital roles in actin dynamics by manipulating the rates of filament polymerization and depolymerization. It has been reported that the S6D and R98A/K100A mutants of actin-depolymerizing factor 1 (ADF1) in Arabidopsis thaliana decreased the binding affinity of ADF for the actin monomer. To investigate the binding mechanism and dynamic behavior of the ADF1–actin complex, we constructed a homology model of the AtADF1–actin complex based on the crystal structure of AtADF1 and the twinfilin C-terminal ADF-H domain in a complex with a mouse actin monomer. The model was then refined for subsequent molecular dynamics simulations. Increased binding energy of the mutated system was observed using the Molecular Mechanics Generalized Born Surface Area and Poisson–Boltzmann Surface Area (MM-GB/PBSA) methods. To determine the residues that make decisive contributions to the ADF1 actin-binding affinity, per-residue decomposition and computational alanine scanning analyses were performed, which provided more detailed information on the binding mechanism. Root-mean-square fluctuation and principal component analyses confirmed that the S6D and R98A/K100A mutants induced an increased conformational flexibility. The comprehensive molecular insight gained from this study is of great importance for understanding the binding mechanism of ADF1 and G-actin. PMID:27414648

  17. Computational Study of the Binding Mechanism of Actin-Depolymerizing Factor 1 with Actin in Arabidopsis thaliana.

    PubMed

    Du, Juan; Wang, Xue; Dong, Chun-Hai; Yang, Jian Ming; Yao, Xiao Jun

    2016-01-01

    Actin is a highly conserved protein. It plays important roles in cellular function and exists either in the monomeric (G-actin) or polymeric form (F-actin). Members of the actin-depolymerizing factor (ADF)/cofilin protein family bind to both G-actin and F-actin and play vital roles in actin dynamics by manipulating the rates of filament polymerization and depolymerization. It has been reported that the S6D and R98A/K100A mutants of actin-depolymerizing factor 1 (ADF1) in Arabidopsis thaliana decreased the binding affinity of ADF for the actin monomer. To investigate the binding mechanism and dynamic behavior of the ADF1-actin complex, we constructed a homology model of the AtADF1-actin complex based on the crystal structure of AtADF1 and the twinfilin C-terminal ADF-H domain in a complex with a mouse actin monomer. The model was then refined for subsequent molecular dynamics simulations. Increased binding energy of the mutated system was observed using the Molecular Mechanics Generalized Born Surface Area and Poisson-Boltzmann Surface Area (MM-GB/PBSA) methods. To determine the residues that make decisive contributions to the ADF1 actin-binding affinity, per-residue decomposition and computational alanine scanning analyses were performed, which provided more detailed information on the binding mechanism. Root-mean-square fluctuation and principal component analyses confirmed that the S6D and R98A/K100A mutants induced an increased conformational flexibility. The comprehensive molecular insight gained from this study is of great importance for understanding the binding mechanism of ADF1 and G-actin. PMID:27414648

  18. Actin is required for IFT regulation in Chlamydomonas reinhardtii.

    PubMed

    Avasthi, Prachee; Onishi, Masayuki; Karpiak, Joel; Yamamoto, Ryosuke; Mackinder, Luke; Jonikas, Martin C; Sale, Winfield S; Shoichet, Brian; Pringle, John R; Marshall, Wallace F

    2014-09-01

    Assembly of cilia and flagella requires intraflagellar transport (IFT), a highly regulated kinesin-based transport system that moves cargo from the basal body to the tip of flagella [1]. The recruitment of IFT components to basal bodies is a function of flagellar length, with increased recruitment in rapidly growing short flagella [2]. The molecular pathways regulating IFT are largely a mystery. Because actin network disruption leads to changes in ciliary length and number, actin has been proposed to have a role in ciliary assembly. However, the mechanisms involved are unknown. In Chlamydomonas reinhardtii, conventional actin is found in both the cell body and the inner dynein arm complexes within flagella [3, 4]. Previous work showed that treating Chlamydomonas cells with the actin-depolymerizing compound cytochalasin D resulted in reversible flagellar shortening [5], but how actin is related to flagellar length or assembly remains unknown. Here we utilize small-molecule inhibitors and genetic mutants to analyze the role of actin dynamics in flagellar assembly in Chlamydomonas reinhardtii. We demonstrate that actin plays a role in IFT recruitment to basal bodies during flagellar elongation and that when actin is perturbed, the normal dependence of IFT recruitment on flagellar length is lost. We also find that actin is required for sufficient entry of IFT material into flagella during assembly. These same effects are recapitulated with a myosin inhibitor, suggesting that actin may act via myosin in a pathway by which flagellar assembly is regulated by flagellar length.

  19. Tropomyosin - master regulator of actin filament function in the cytoskeleton.

    PubMed

    Gunning, Peter W; Hardeman, Edna C; Lappalainen, Pekka; Mulvihill, Daniel P

    2015-08-15

    Tropomyosin (Tpm) isoforms are the master regulators of the functions of individual actin filaments in fungi and metazoans. Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two Tpm isoforms, whereas mammals have over 40. Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition along its length. Evidence for this 'master regulator' role is based on four core sets of observation. First, spatially and functionally distinct actin filaments contain different Tpm isoforms, and recent data suggest that members of the formin family of actin filament nucleators can specify which Tpm isoform is added to the growing actin filament. Second, Tpms regulate whole-organism physiology in terms of morphogenesis, cell proliferation, vesicle trafficking, biomechanics, glucose metabolism and organ size in an isoform-specific manner. Third, Tpms achieve these functional outputs by regulating the interaction of actin filaments with myosin motors and actin-binding proteins in an isoform-specific manner. Last, the assembly of complex structures, such as stress fibers and podosomes involves the collaboration of multiple types of actin filament specified by their Tpm composition. This allows the cell to specify actin filament function in time and space by simply specifying their Tpm isoform composition.

  20. The neuronal and actin commitment: Why do neurons need rings?

    PubMed

    Leite, Sérgio Carvalho; Sousa, Mónica Mendes

    2016-09-01

    The role of the actin cytoskeleton in neurons has been extensively studied in actin-enriched compartments such as the growth cone and dendritic spines. The recent discovery of actin rings in the axon shaft and in dendrites, together with the identification of axon actin trails, has advanced our understanding on actin organization and dynamics in neurons. However, specifically in the case of actin rings, the mechanisms regulating their nucleation and assembly, and the functions that they may exert in axons and dendrites remain largely unexplored. Here we discuss the possible structural, mechanistic and functional properties of the subcortical neuronal cytoskeleton putting the current knowledge in perspective with the information available on actin rings formed in other biological contexts, and with the organization of actin-spectrin lattices in other cell types. The detailed analysis of these novel neuronal actin ring structures, together with the elucidation of the function of actin-binding proteins in neuron biology, has a large potential to uncover new mechanisms of neuronal function under normal conditions that may have impact in our understanding of axon degeneration and regeneration. © 2016 Wiley Periodicals, Inc.