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.

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

NASA Astrophysics Data System (ADS)

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

2017-03-01

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

Dynamic mask for producing uniform or graded-thickness thin films

DOEpatents

Folta, James A [Livermore, CA

2006-06-13

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

Microscale Patterning of Thermoplastic Polymer Surfaces by Selective Solvent Swelling

PubMed Central

Rahmanian, Omid; Chen, Chien-Fu; DeVoe, Don L.

2012-01-01

A new method for the fabrication of microscale features in thermoplastic substrates is presented. Unlike traditional thermoplastic microfabrication techniques, in which bulk polymer is displaced from the substrate by machining or embossing, a unique process termed orogenic microfabrication has been developed in which selected regions of a thermoplastic surface are raised from the substrate by an irreversible solvent swelling mechanism. The orogenic technique allows thermoplastic surfaces to be patterned using a variety of masking methods, resulting in three-dimensional features that would be difficult to achieve through traditional microfabrication methods. Using cyclic olefin copolymer as a model thermoplastic material, several variations of this process are described to realize growth heights ranging from several nanometers to tens of microns, with patterning techniques include direct photoresist masking, patterned UV/ozone surface passivation, elastomeric stamping, and noncontact spotting. Orogenic microfabrication is also demonstrated by direct inkjet printing as a facile photolithography-free masking method for rapid desktop thermoplastic microfabrication. PMID:22900539

Process for the Production of Star Tracklng [Tracking] Reticles

NASA Technical Reports Server (NTRS)

Smith, Wade O. (Inventor); Toft, Albert R. (Inventor)

1972-01-01

A method for the production of reticles, particularly those for use in outer space, wherein the product is a quartz base coated with highly adherent layers of chromium, chromium-silver, and silver vacuum deposited through a mask, and then coated with an electrodeposit of copper from a copper sulfate solution followed by an electrodeposit of black chromium. The masks are produced by coating a beryllium-copper alloy substrate with a positive working photoresist, developing the photoresist according to a pattern to leave a positive mask, plating uncoated areas with gold, removing the photoresist, coating the substrate with a negative working photoresist, developing the negative working photoresist to expose the base metal of the pattern, and chemically etching the unplated side of the pattern to produce the mask. The mask produced is then used in the vacuum deposition of: (1) chromium metal on the surface of a quartz base to obtain a highly adherent quartz-chromium interface; (2) silver on the chromium deposit, during the final stage of chromium deposit, to produce a silver chromium alloy layer; and (3) silver onto the surface of the alloy layer. The coated quartz base is then coated by electroplating utilizing an acid copper deposit followed by a black chromium electrodeposit to produce the product of the present invention.

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

NASA Astrophysics Data System (ADS)

Yanagishita, Takashi; Masuda, Hideki

2016-08-01

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

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

NASA Astrophysics Data System (ADS)

Kimmel, Kurt R.; Hughes, Patrick J.

1996-07-01

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

Pattern transfer with stabilized nanoparticle etch masks

NASA Astrophysics Data System (ADS)

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

2013-03-01

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

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

NASA Astrophysics Data System (ADS)

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

2013-09-01

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

Germanium Lift-Off Masks for Thin Metal Film Patterning

NASA Technical Reports Server (NTRS)

Brown, Ari

2012-01-01

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

High-quality GaN epitaxially grown on Si substrate with serpentine channels

NASA Astrophysics Data System (ADS)

Wei, Tiantian; Zong, Hua; Jiang, Shengxiang; Yang, Yue; Liao, Hui; Xie, Yahong; Wang, Wenjie; Li, Junze; Tang, Jun; Hu, Xiaodong

2018-06-01

A novel serpentine-channeled mask was introduced to Si substrate for low-dislocation GaN epitaxial growth and the fully coalesced GaN film on the masked Si substrate was achieved for the first time. Compared with the epitaxial lateral overgrowth (ELOG) growth method, this innovative mask only requires one-step epitaxial growth of GaN which has only one high-dislocation region per mask opening. This new growth method can effectively reduce dislocation density, thus improving the quality of GaN significantly. High-quality GaN with low dislocation density ∼2.4 × 107 cm-2 was obtained, which accounted for about eighty percent of the GaN film in area. This innovative technique is promising for the growth of high-quality GaN templates and the subsequent fabrication of high-performance GaN-based devices like transistors, laser diodes (LDs), and light-emitting diodes (LEDs) on Si substrate.

Status of EUVL mask development in Europe (Invited Paper)

NASA Astrophysics Data System (ADS)

Peters, Jan H.

2005-06-01

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

Fabrication and characterisation of embedded metal nanostructures by ion implantation with nanoporous anodic alumina masks

NASA Astrophysics Data System (ADS)

Guan, Wei; Peng, Nianhua; Jeynes, Christopher; Ghatak, Jay; Peng, Yong; Ross, Ian M.; Bhatta, Umananda M.; Inkson, Beverley J.; Möbus, Günter

2013-07-01

Lateral ordered Co, Pt and Co/Pt nanostructures were fabricated in SiO2 and Si3N4 substrates by high fluence metal ion implantation through periodic nanochannel membrane masks based on anodic aluminium oxides (AAO). The quality of nanopatterning transfer defined by various AAO masks in different substrates was examined by transmission electron microscopy (TEM) in both imaging and spectroscopy modes.

Umbra/penumbra detector

DOEpatents

Carner, Jr., Don C.

1988-01-01

A device which monitors the characteristics of an image cast upon a radiation sensitive substrate. This includes a shadow casting object or mask and at least one source of radiation disposed above the object or mask so that the image cast on the substrate can be analyzed.

Nanofabrication on unconventional substrates using transferred hard masks

DOE PAGES

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

2015-01-15

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

Masking ability of a zirconia ceramic on composite resin substrate shades.

PubMed

Tabatabaian, Farhad; Shabani, Sima; Namdari, Mahshid; Sadeghpour, Koroush

2017-01-01

Masking ability of a restorative material plays an important role to cover discolored tooth structure; however, this ability has not yet been well understood in zirconia-based restorations. This study assessed the masking ability of a zirconia ceramic on composite resin substrates with different shades. Ten zirconia disc specimens, with 0.5 mm thickness and 10 mm diameter, were fabricated by a computer-aided design/computer-aided manufacturing system. A white substrate (control) and six composite resin substrates with different shades including A1, A2, A3, B2, C2, and D3 were prepared. The substrates had a cylindrical shape with 10 mm diameter and height. The specimens were placed onto the substrates for spectrophotometric evaluation. A spectrophotometer measured the L*, a*, and b* values for the specimens. ΔE values were calculated to determine the color differences between the groups and the control and then were compared with a perceptional threshold (ΔE = 2.6). Repeated measures ANOVA and Bonferroni tests were used for data analysis ( P < 0.05). The mean and standard deviation of ΔE values for A1, A2, A3, B2, C2, and D3 groups were 6.78 ± 1.59, 8.13 ± 1.66, 9.81 ± 2.64, 9.61 ± 1.38, 9.59 ± 2.63, and 8.13 ± 1.89, respectively. A significant difference was found among the groups in the ΔE values ( P = 0.006). The ΔE values were more than the perceptional threshold in all the groups ( P < 0.0001). Within the limitations of this study, it can be concluded that the tested zirconia ceramic could not thoroughly mask different shades of the composite resin substrates. Moreover, color masking of zirconia depends on the shade of substrate.

Umbra/penumbra detector

DOEpatents

Carner, D.C. Jr.

1988-10-11

A device which monitors the characteristics of an image cast upon a radiation sensitive substrate. This includes a shadow casting object or mask and at least one source of radiation disposed above the object or mask so that the image cast on the substrate can be analyzed. 23 figs.

Growth of arrays of oriented epitaxial platinum nanoparticles with controlled size and shape by natural colloidal lithography

DOE PAGES

Komanicky, Vladimir; Barbour, Andi; Lackova, Miroslava; ...

2014-07-05

Here, we developed a method for production of arrays of platinum nanocrystals of controlled size and shape using templates from ordered silica bead monolayers. Silica beads with nominal sizes of 150 and 450 nm were self-assembl into monolayers over strontium titanate single crystal substrates. The monolayers were used as shadow masks for platinum metal deposition on the substrate using the three-step evaporation technique. Produced arrays of epitaxial platinum islands were transformed into nanocrystals by annealing in a quartz tube in nitrogen flow. The shape of particles is determined by the substrate crystallography, while the size of the particles and theirmore » spacing are controlled by the size of the silica beads in the mono- layer mask. As a proof of concept, arrays of platinum nanocrystals of cubooctahedral shape were prepared on (100) strontium titanate substrates. We also characterized the nanocrystal arrays by atomic force microscopy, scanning electron microscopy, and synchrotron X-ray diffraction techniques.« less

Methods of fabrication of graphene nanoribbons

DOEpatents

Zhang, Yuegang

2015-06-23

Methods of fabricating graphene nanoribbons include depositing a catalyst layer on a substrate. A masking layer is deposited on the catalyst layer. The masking layer and the catalyst layer are etched to form a structure on the substrate, the structure comprising a portion of the catalyst layer and a portion of the masking layer disposed on the catalyst layer, with sidewalls of the catalyst layer being exposed. A graphene layer is formed on a sidewall of the catalyst layer with a carbon-containing gas.

X-ray mask and method for providing same

DOEpatents

Morales, Alfredo M [Pleasanton, CA; Skala, Dawn M [Fremont, CA

2004-09-28

The present invention describes a method for fabricating an x-ray mask tool which can achieve pattern features having lateral dimension of less than 1 micron. The process uses a thin photoresist and a standard lithographic mask to transfer an trace image pattern in the surface of a silicon wafer by exposing and developing the resist. The exposed portion of the silicon substrate is then anisotropically etched to provide an etched image of the trace image pattern consisting of a series of channels in the silicon having a high depth-to-width aspect ratio. These channels are then filled by depositing a metal such as gold to provide an inverse image of the trace image and thereby providing a robust x-ray mask tool.

X-ray mask and method for providing same

DOEpatents

Morales, Alfredo M.; Skala, Dawn M.

2002-01-01

The present invention describes a method for fabricating an x-ray mask tool which can achieve pattern features having lateral dimension of less than 1 micron. The process uses a thin photoresist and a standard lithographic mask to transfer an trace image pattern in the surface of a silicon wafer by exposing and developing the resist. The exposed portion of the silicon substrate is then anisotropically etched to provide an etched image of the trace image pattern consisting of a series of channels in the silicon having a high depth-to-width aspect ratio. These channels are then filled by depositing a metal such as gold to provide an inverse image of the trace image and thereby providing a robust x-ray mask tool.

Approach to high quality GaN lateral nanowires and planar cavities fabricated by focused ion beam and metal-organic vapor phase epitaxy.

PubMed

Pozina, Galia; Gubaydullin, Azat R; Mitrofanov, Maxim I; Kaliteevski, Mikhail A; Levitskii, Iaroslav V; Voznyuk, Gleb V; Tatarinov, Evgeniy E; Evtikhiev, Vadim P; Rodin, Sergey N; Kaliteevskiy, Vasily N; Chechurin, Leonid S

2018-05-08

We have developed a method to fabricate GaN planar nanowires and cavities by combination of Focused Ion Beam (FIB) patterning of the substrate followed by Metal Organic Vapor Phase Epitaxy (MOVPE). The method includes depositing a silicon nitride mask on a sapphire substrate, etching of the trenches in the mask by FIB with a diameter of 40 nm with subsequent MOVPE growth of GaN within trenches. It was observed that the growth rate of GaN is substantially increased due to enhanced bulk diffusion of the growth precursor therefore the model for analysis of the growth rate was developed. The GaN strips fabricated by this method demonstrate effective luminescence properties. The structures demonstrate enhancement of spontaneous emission via formation of Fabry-Perot modes.

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.

Nanoimprint system development and status for high volume semiconductor manufacturing

NASA Astrophysics Data System (ADS)

Hiura, Hiromi; Takabayashi, Yukio; Takashima, Tsuneo; Emoto, Keiji; Choi, Jin; Schumaker, Phil

2016-10-01

Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Jet and Flash Imprint Lithography* (J-FIL*) 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 resist on the substrate. There are many criteria that determine whether a particular technology is ready for wafer manufacturing. For imprint lithography, recent attention has been given to the areas of overlay, throughput, defectivity, and mask replication. This paper reviews progress in these critical areas. Recent demonstrations have proven that mix and match overlay of less than 5nm can achieved. Further reductions require a higher order correction system. Modeling and experimental data are presented which provide a path towards reducing the overlay errors to less than 3nm. Throughput is mainly impacted by the fill time of the relief images on the mask. Improvement in resist materials provides a solution that allows 15 wafers per hour per station, or a tool throughput of 60 wafers per hour. Defectivity and mask life play a significant role relative to meeting the cost of ownership (CoO) requirements in the production of semiconductor devices. Hard particles on a wafer or mask create the possibility of inducing a permanent defect on the mask that can impact device yield and mask life. By using material methods to reduce particle shedding and by introducing an air curtain system, the lifetime of both the master mask and the replica mask can be extended. In this work, we report results that demonstrate a path towards achieving mask lifetimes of better than 1000 wafers. Finally, on the mask side, a new replication tool, the FPA-1100NR2 is introduced. Mask replication is required for nanoimprint lithography (NIL), and criteria that are crucial to the success of a replication platform include both particle control and IP accuracy. In particular, by improving the specifications on the mask chuck, residual errors of only 1nm can be realized.

Two-dimensional analytical modeling of a linear variable filter for spectral order sorting.

PubMed

Ko, Cheng-Hao; Wu, Yueh-Hsun; Tsai, Jih-Run; Wang, Bang-Ji; Chakraborty, Symphony

2016-06-10

A two-dimensional thin film thickness model based on the geometry of a commercial coater which can calculate more effectively the profiles of linear variable filters (LVFs) has been developed. This is done by isolating the substrate plane as an independent coordinate (local coordinate), while the rotation and translation matrices are used to establish the coordinate transformation and combine the characteristic vector with the step function to build a borderline which can conclude whether the local mask will block the deposition or not. The height of the local mask has been increased up to 40 mm in the proposed model, and two-dimensional simulations are developed to obtain a thin film profile deposition on the substrate inside the evaporation chamber to achieve the specific request of producing a LVF zone width in a more economical way than previously reported [Opt. Express23, 5102 (2015)OPEXFF1094-408710.1364/OE.23.005102].

Uniformity Masks Design Method Based on the Shadow Matrix for Coating Materials with Different Condensation Characteristics

PubMed Central

2013-01-01

An intuitionistic method is proposed to design shadow masks to achieve thickness profile control for evaporation coating processes. The proposed method is based on the concept of the shadow matrix, which is a matrix that contains coefficients that build quantitive relations between shape parameters of masks and shadow quantities of substrate directly. By using the shadow matrix, shape parameters of shadow masks could be derived simply by solving a matrix equation. Verification experiments were performed on a special case where coating materials have different condensation characteristics. By using the designed mask pair with complementary shapes, thickness uniformities of better than 98% are demonstrated for MgF2 (m = 1) and LaF3 (m = 0.5) simultaneously on a 280 mm diameter spherical substrate with the radius curvature of 200 mm. PMID:24227996

Optical inspection of NGL masks

NASA Astrophysics Data System (ADS)

Pettibone, Donald W.; Stokowski, Stanley E.

2004-12-01

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

High speed, mask-less, laser controlled deposition of microscale tungsten tracks using 405 nm wavelength diode laser

NASA Astrophysics Data System (ADS)

Ten, Jyi Sheuan; Sparkes, Martin; O'Neill, William

2017-02-01

A rapid, mask-less deposition technique for the deposition of conductive tracks to nano- and micro-devices has been developed. The process uses a 405 nm wavelength laser diode for the direct deposition of tungsten tracks on silicon substrates via laser assisted chemical vapour deposition. Unlike lithographic processes this technique is single step and does not require chemical masks that may contaminate the substrate. To demonstrate the process, tungsten was deposited from tungsten hexacarbonyl precursors to produce conductive tracks with widths of 1.7-28 μm and heights of 0.05-35 μm at laser scan speeds up to 40 μm/s. The highest volumetric deposition rate achieved is 1×104 μm3/s, three orders of magnitude higher than that of focused ion beam deposition and on par with a 515 nm wavelength argon ion laser previously reported as the laser source. The microstructure and elemental composition of the deposits are comparable to that of largearea chemical vapour deposition methods using the same chemical precursor. The contact resistance and track resistance of the deposits has been measured using the transfer length method to be 205 μΩ cm. The deposition temperature has been estimated at 334 °C from a laser heat transfer model accounting for temperature dependent optical and physical properties of the substrate. The peak temperatures achieved on silicon and other substrates are higher than the thermal dissociation temperature of numerous precursors, indicating that this technique can also be used to deposit other materials such as gold and platinum on various substrates.

Low resistance thin film organic solar cell electrodes

DOEpatents

Forrest, Stephen [Princeton, NJ; Xue, Jiangeng [Piscataway, NJ

2008-01-01

A method which lower the series resistance of photosensitive devices includes providing a transparent film of a first electrically conductive material arranged on a transparent substrate; depositing and patterning a mask over the first electrically conductive material, such that openings in the mask have sloping sides which narrow approaching the substrate; depositing a second electrically conductive material directly onto the first electrically conductive material exposed in the openings of the mask, at least partially filling the openings; stripping the mask, leaving behind reentrant structures of the second electrically conductive material which were formed by the deposits in the openings of the mask; after stripping the mask, depositing a first organic material onto the first electrically conductive material in between the reentrant structures; and directionally depositing a third electrically conductive material over the first organic material deposited in between the reentrant structures, edges of the reentrant structures aligning deposition so that the third electrically conductive material does not directly contact the first electrically conductive material, and does not directly contact the second electrically conductive material.

Mask pattern generator employing EPL technology

NASA Astrophysics Data System (ADS)

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

2003-08-01

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

An alternative route for the synthesis of silicon nanowires via porous anodic alumina masks

PubMed Central

2011-01-01

Amorphous Si nanowires have been directly synthesized by a thermal processing of Si substrates. This method involves the deposition of an anodic aluminum oxide mask on a crystalline Si (100) substrate. Fe, Au, and Pt thin films with thicknesses of ca. 30 nm deposited on the anodic aluminum oxide-Si substrates have been used as catalysts. During the thermal treatment of the samples, thin films of the metal catalysts are transformed in small nanoparticles incorporated within the pore structure of the anodic aluminum oxide mask, directly in contact with the Si substrate. These homogeneously distributed metal nanoparticles are responsible for the growth of Si nanowires with regular diameter by a simple heating process at 800°C in an Ar-H2 atmosphere and without an additional Si source. The synthesized Si nanowires have been characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman. PMID:21849077

Thermal Management in Nanofiber-Based Face Mask

DOE PAGES

Yang, Ankun; Cai, Lili; Zhang, Rufan; ...

2017-05-15

Face masks are widely used to filter airborne pollutants, especially when particulate matter (PM) pollution has become a serious concern to public health. Here in this paper, the concept of thermal management is introduced into face masks for the first time to enhance the thermal comfort of the user. A system of nanofiber on nanoporous polyethylene (fiber/nanoPE) is developed where the nanofibers with strong PM adhesion ensure high PM capture efficiency (99.6% for PM 2.5) with low pressure drop and the nanoPE substrate with high-infrared (IR) transparency (92.1%, weighted based on human body radiation) results in effective radiative cooling. Wemore » further demonstrate that by coating nanoPE with a layer of Ag, the fiber/Ag/nanoPE mask shows a high IR reflectance (87.0%) and can be used for warming purposes. These multifunctional face mask designs can be explored for both outdoor and indoor applications to protect people from PM pollutants and simultaneously achieve personal thermal comfort.« less

Thermal Management in Nanofiber-Based Face Mask.

PubMed

Yang, Ankun; Cai, Lili; Zhang, Rufan; Wang, Jiangyan; Hsu, Po-Chun; Wang, Hongxia; Zhou, Guangmin; Xu, Jinwei; Cui, Yi

2017-06-14

Face masks are widely used to filter airborne pollutants, especially when particulate matter (PM) pollution has become a serious concern to public health. Here, the concept of thermal management is introduced into face masks for the first time to enhance the thermal comfort of the user. A system of nanofiber on nanoporous polyethylene (fiber/nanoPE) is developed where the nanofibers with strong PM adhesion ensure high PM capture efficiency (99.6% for PM 2.5 ) with low pressure drop and the nanoPE substrate with high-infrared (IR) transparency (92.1%, weighted based on human body radiation) results in effective radiative cooling. We further demonstrate that by coating nanoPE with a layer of Ag, the fiber/Ag/nanoPE mask shows a high IR reflectance (87.0%) and can be used for warming purposes. These multifunctional face mask designs can be explored for both outdoor and indoor applications to protect people from PM pollutants and simultaneously achieve personal thermal comfort.

Thermal Management in Nanofiber-Based Face Mask

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

Yang, Ankun; Cai, Lili; Zhang, Rufan

Face masks are widely used to filter airborne pollutants, especially when particulate matter (PM) pollution has become a serious concern to public health. Here in this paper, the concept of thermal management is introduced into face masks for the first time to enhance the thermal comfort of the user. A system of nanofiber on nanoporous polyethylene (fiber/nanoPE) is developed where the nanofibers with strong PM adhesion ensure high PM capture efficiency (99.6% for PM 2.5) with low pressure drop and the nanoPE substrate with high-infrared (IR) transparency (92.1%, weighted based on human body radiation) results in effective radiative cooling. Wemore » further demonstrate that by coating nanoPE with a layer of Ag, the fiber/Ag/nanoPE mask shows a high IR reflectance (87.0%) and can be used for warming purposes. These multifunctional face mask designs can be explored for both outdoor and indoor applications to protect people from PM pollutants and simultaneously achieve personal thermal comfort.« less

Dry etching technologies for reflective multilayer

NASA Astrophysics Data System (ADS)

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

2012-11-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Nanoimprint wafer and mask tool progress and status for high volume semiconductor manufacturing

NASA Astrophysics Data System (ADS)

Matsuoka, Yoichi; Seki, Junichi; Nakayama, Takahiro; Nakagawa, Kazuki; Azuma, Hisanobu; Yamamoto, Kiyohito; Sato, Chiaki; Sakai, Fumio; Takabayashi, Yukio; Aghili, Ali; Mizuno, Makoto; Choi, Jin; Jones, Chris E.

2016-10-01

Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Jet and Flash* Imprint Lithography (J-FIL*) 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 resist on the substrate. There are many criteria that determine whether a particular technology is ready for wafer manufacturing. Defectivity and mask life play a significant role relative to meeting the cost of ownership (CoO) requirements in the production of semiconductor devices. Hard particles on a wafer or mask create the possibility of inducing a permanent defect on the mask that can impact device yield and mask life. By using material methods to reduce particle shedding and by introducing an air curtain system, the lifetime of both the master mask and the replica mask can be extended. In this work, we report results that demonstrate a path towards achieving mask lifetimes of better than 1000 wafers. On the mask side, a new replication tool, the FPA-1100 NR2 is introduced. Mask replication is required for nanoimprint lithography (NIL), and criteria that are crucial to the success of a replication platform include both particle control, resolution and image placement accuracy. In this paper we discuss the progress made in both feature resolution and in meeting the image placement specification for replica masks.

Development of Ordered, Porous (Sub-25 nm Dimensions) Surface Membrane Structures Using a Block Copolymer Approach.

PubMed

Ghoshal, Tandra; Holmes, Justin D; Morris, Michael A

2018-05-08

In an effort to develop block copolymer lithography to create high aspect vertical pore arrangements in a substrate surface we have used a microphase separated poly(ethylene oxide) -b- polystyrene (PEO-b-PS) block copolymer (BCP) thin film where (and most unusually) PS not PEO is the cylinder forming phase and PEO is the majority block. Compared to previous work, we can amplify etch contrast by inclusion of hard mask material into the matrix block allowing the cylinder polymer to be removed and the exposed substrate subject to deep etching thereby generating uniform, arranged, sub-25 nm cylindrical nanopore arrays. Briefly, selective metal ion inclusion into the PEO matrix and subsequent processing (etch/modification) was applied for creating iron oxide nanohole arrays. The oxide nanoholes (22 nm diameter) were cylindrical, uniform diameter and mimics the original BCP nanopatterns. The oxide nanohole network is demonstrated as a resistant mask to fabricate ultra dense, well ordered, good sidewall profile silicon nanopore arrays on substrate surface through the pattern transfer approach. The Si nanopores have uniform diameter and smooth sidewalls throughout their depth. The depth of the porous structure can be controlled via the etch process.

Small feature sizes and high aperture ratio organic light-emitting diodes by using laser-patterned polyimide shadow masks

NASA Astrophysics Data System (ADS)

Kajiyama, Yoshitaka; Joseph, Kevin; Kajiyama, Koichi; Kudo, Shuji; Aziz, Hany

2014-02-01

A shadow mask technique capable of realizing high resolution (>330 pixel-per-inch) and ˜100% aperture ratio Organic Light-Emitting Diode (OLED) full color displays is demonstrated. The technique utilizes polyimide contact shadow masks, patterned by laser ablation. Red, green, and blue OLEDs with very small feature sizes (<25 μm) are fabricated side by side on one substrate. OLEDs fabricated via this technique have the same performance as those made by established technology. This technique has a strong potential to achieve high resolution OLED displays via standard vacuum deposition processes even on flexible substrates.

Self-organized broadband light trapping in thin film amorphous silicon solar cells.

PubMed

Martella, C; Chiappe, D; Delli Veneri, P; Mercaldo, L V; Usatii, I; Buatier de Mongeot, F

2013-06-07

Nanostructured glass substrates endowed with high aspect ratio one-dimensional corrugations are prepared by defocused ion beam erosion through a self-organized gold (Au) stencil mask. The shielding action of the stencil mask is amplified by co-deposition of gold atoms during ion bombardment. The resulting glass nanostructures enable broadband anti-reflection functionality and at the same time ensure a high efficiency for diffuse light scattering (Haze). It is demonstrated that the patterned glass substrates exhibit a better photon harvesting than the flat glass substrate in p-i-n type thin film a-Si:H solar cells.

Twisted multifilament superconductor

NASA Technical Reports Server (NTRS)

Coles, W. D. (Inventor)

1973-01-01

Masking selected portions of a ribbon and forming an intermetallic compound on the unmasked portions by a controlled diffusion reaction produces a twisted filamentary structure. The masking material prohibits the formation of superconductive material on predetermined areas of the substrate.

Plasma cleaning of nanoparticles from EUV mask materials by electrostatics

NASA Astrophysics Data System (ADS)

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

2008-03-01

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

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

NASA Astrophysics Data System (ADS)

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

2004-06-01

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

Fast prototyping of high-aspect ratio, high-resolution x-ray masks by gas-assisted focused ion beam

NASA Technical Reports Server (NTRS)

Hartley, F.; Malek, C.; Neogi, J.

2001-01-01

The capacity of chemically-assisted focused ion beam (fib) etching systems to undertake direct and highly anisotropic erosion of thin and thick gold (or other high atomic number [Z])coatings on x-ray mask membranes/substrates provides new levels of precision, flexibility, simplification and rapidity in the manufacture of mask absorber patterns, allowing the fast prototyping of high aspect ratio, high-resolution masks for deep x-ray lithography.

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

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

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

2010-03-12

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

Mask-to-wafer alignment system

DOEpatents

Sweatt, William C.; Tichenor, Daniel A.; Haney, Steven J.

2003-11-04

A modified beam splitter that has a hole pattern that is symmetric in one axis and anti-symmetric in the other can be employed in a mask-to-wafer alignment device. The device is particularly suited for rough alignment using visible light. The modified beam splitter transmits and reflects light from a source of electromagnetic radiation and it includes a substrate that has a first surface facing the source of electromagnetic radiation and second surface that is reflective of said electromagnetic radiation. The substrate defines a hole pattern about a central line of the substrate. In operation, an input beam from a camera is directed toward the modified beam splitter and the light from the camera that passes through the holes illuminates the reticle on the wafer. The light beam from the camera also projects an image of a corresponding reticle pattern that is formed on the mask surface of the that is positioned downstream from the camera. Alignment can be accomplished by detecting the radiation that is reflected from the second surface of the modified beam splitter since the reflected radiation contains both the image of the pattern from the mask and a corresponding pattern on the wafer.

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

PubMed

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

2015-02-27

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

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.

Maskless deposition technique for the physical vapor deposition of thin film and multilayer coatings with subnanometer precision and accuracy

DOEpatents

Vernon, Stephen P.; Ceglio, Natale M.

2000-01-01

The invention is a method for the production of axially symmetric, graded and ungraded thickness thin film and multilayer coatings that avoids the use of apertures or masks to tailor the deposition profile. A motional averaging scheme permits the deposition of uniform thickness coatings independent of the substrate radius. Coating uniformity results from an exact cancellation of substrate radius dependent terms, which occurs when the substrate moves at constant velocity. If the substrate is allowed to accelerate over the source, arbitrary coating profiles can be generated through appropriate selection and control of the substrate center of mass equation of motion. The radial symmetry of the coating profile is an artifact produced by orbiting the substrate about its center of mass; other distributions are obtained by selecting another rotation axis. Consequently there is a direct mapping between the coating thickness and substrate equation of motion which can be used to tailor the coating profile without the use of masks and apertures.

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

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Method for providing an arbitrary three-dimensional microstructure in silicon using an anisotropic deep etch

DOEpatents

Morales, Alfredo M.; Gonzales, Marcela

2004-06-15

The present invention describes a method for fabricating an embossing tool or an x-ray mask tool, providing microstructures that smoothly vary in height from point-to-point in etched substrates, i.e., structure which can vary in all three dimensions. The process uses a lithographic technique to transfer an image pattern in the surface of a silicon wafer by exposing and developing the resist and then etching the silicon substrate. Importantly, the photoresist is variably exposed so that when developed some of the resist layer remains. The remaining undeveloped resist acts as an etchant barrier to the reactive plasma used to etch the silicon substrate and therefore provides the ability etch structures of variable depths.

Control of spectral transmission enhancement properties of random anti-reflecting surface structures fabricated using gold masking

NASA Astrophysics Data System (ADS)

Peltier, Abigail; Sapkota, Gopal; Potter, Matthew; Busse, Lynda E.; Frantz, Jesse A.; Shaw, L. Brandon; Sanghera, Jasbinder S.; Aggarwal, Ishwar D.; Poutous, Menelaos K.

2017-02-01

Random anti-reflecting subwavelength surface structures (rARSS) have been shown to suppress Fresnel reflection and scatter from optical surfaces. The structures effectively function as a gradient-refractive-index at the substrate boundary, and the spectral transmission properties of the boundary have been shown to depend on the structure's statistical properties (diameter, height, and density.) We fabricated rARSS on fused silica substrates using gold masking. A thin layer of gold was deposited on the surface of the substrate and then subjected to a rapid thermal annealing (RTA) process at various temperatures. This RTA process resulted in the formation of gold "islands" on the surface of the substrate, which then acted as a mask while the substrate was dry etched in a reactive ion etching (RIE) process. The plasma etch yielded a fused silica surface covered with randomly arranged "rods" that act as the anti-reflective layer. We present data relating the physical characteristics of the gold "island" statistical populations, and the resulting rARSS "rod" population, as well as, optical scattering losses and spectral transmission properties of the final surfaces. We focus on comparing results between samples processed at different RTA temperatures, as well as samples fabricated without undergoing RTA, to relate fabrication process statistics to transmission enhancement values.

Multi-shaped beam: development status and update on lithography results

NASA Astrophysics Data System (ADS)

Slodowski, Matthias; Doering, Hans-Joachim; Dorl, Wolfgang; Stolberg, Ines A.

2011-04-01

According to the ITRS [1] photo mask is a significant challenge for the 22nm technology node requirements and beyond. Mask making capability and cost escalation continue to be critical for future lithography progress. On the technological side mask specifications and complexity have increased more quickly than the half-pitch requirements on the wafer designated by the roadmap due to advanced optical proximity correction and double patterning demands. From the economical perspective mask costs have significantly increased each generation, in which mask writing represents a major portion. The availability of a multi-electron-beam lithography system for mask write application is considered a potential solution to overcome these challenges [2, 3]. In this paper an update of the development status of a full-package high-throughput multi electron-beam writer, called Multi Shaped Beam (MSB), will be presented. Lithography performance results, which are most relevant for mask writing applications, will be disclosed. The MSB technology is an evolutionary development of the matured single Variable Shaped Beam (VSB) technology. An arrangement of Multi Deflection Arrays (MDA) allows operation with multiple shaped beams of variable size, which can be deflected and controlled individually [4]. This evolutionary MSB approach is associated with a lower level of risk and a relatively short time to implementation compared to the known revolutionary concepts [3, 5, 6]. Lithography performance is demonstrated through exposed pattern. Further details of the substrate positioning platform performance will be disclosed. It will become apparent that the MSB operational mode enables lithography on the same and higher performance level compared to single VSB and that there are no specific additional lithography challenges existing beside those which have already been addressed [1].

Ion Beam Sputtered Coatings of Bioglass

NASA Technical Reports Server (NTRS)

Hench, Larry L.; Wilson, J.; Ruzakowski, Patricia Henrietta Anne

1982-01-01

The ion beam sputtering technique available at the NASA-Lewis was used to apply coatings of bioglass to ceramic, metallic, and polymeric substrates. Experiments in vivo and in vitro described investigate these coatings. Some degree of substrate masking was obtained in all samples although stability and reactivity equivalent to bulk bioglass was not observed in all coated samples. Some degree of stability was seen in all coated samples that were reacted in vitro. Both metallic and ceramic substrates coated in this manner failed to show significantly improved coatings over those obtained with existing techniques. Implantation of the coated ceramic substrate samples in bone gave no definite bonding as seen with bulk glass; however, partial and patchy bonding was seen. Polymeric substrates in these studies showed promise of success. The coatings applied were sufficient to mask the underlying reactive test surface and tissue adhesion of collagen to bioglass was seen. Hydrophilic, hydrophobic, charged, and uncharged polymeric surfaces were successfully coated.

Nanoepitaxy of GaAs on a Si(001) substrate using a round-hole nanopatterned SiO2 mask.

PubMed

Hsu, Chao-Wei; Chen, Yung-Feng; Su, Yan-Kuin

2012-12-14

GaAs is grown by metal-organic vapor-phase epitaxy on a 55 nm round-hole patterned Si substrate with SiO(2) as a mask. The threading dislocations, which are stacked on the lowest energy facet plane, move along the SiO(2) walls, reducing the number of dislocations. The etching pit density of GaAs on the 55 nm round-hole patterned Si substrate is about 3.3 × 10(5) cm(-2). Compared with the full width at half maximum measurement from x-ray diffraction and photoluminescence spectra of GaAs on a planar Si(001) substrate, those of GaAs on the 55 nm round-hole patterned Si substrate are reduced by 39.6 and 31.4%, respectively. The improvement in material quality is verified by transmission electron microscopy, field-emission scanning electron microscopy, Hall measurements, Raman spectroscopy, photoluminescence, and x-ray diffraction studies.

Modeling of projection electron lithography

NASA Astrophysics Data System (ADS)

Mack, Chris A.

2000-07-01

Projection Electron Lithography (PEL) has recently become a leading candidate for the next generation of lithography systems after the successful demonstration of SCAPEL by Lucent Technologies and PREVAIL by IBM. These systems use a scattering membrane mask followed by a lens with limited angular acceptance range to form an image of the mask when illuminated by high energy electrons. This paper presents an initial modeling system for such types of projection electron lithography systems. Monte Carlo modeling of electron scattering within the mask structure creates an effective mask 'diffraction' pattern, to borrow the standard optical terminology. A cutoff of this scattered pattern by the imaging 'lens' provides an electron energy distribution striking the wafer. This distribution is then convolved with a 'point spread function,' the results of a Monte Carlo scattering calculation of a point beam of electrons striking the resist coated substrate and including the effects of beam blur. Resist exposure and development models from standard electron beam lithography simulation are used to simulate the final three-dimensional resist profile.

Development of binary image masks for TPF-C and ground-based AO coronagraphs

NASA Astrophysics Data System (ADS)

Ge, Jian; Crepp, Justin; Vanden Heuvel, Andrew; Miller, Shane; McDavitt, Dan; Kravchenko, Ivan; Kuchner, Marc

2006-06-01

We report progress on the development of precision binary notch-filter focal plane coronagraphic masks for directly imaging Earth-like planets at visible wavelengths with the Terrestrial Planet Finder Coronagraph (TPF-C), and substellar companions at near infrared wavelengths from the ground with coronagraphs coupled to high-order adaptive optics (AO) systems. Our recent theoretical studies show that 8th-order image masks (Kuchner, Crepp & Ge 2005, KCG05) are capable of achieving unlimited dynamic range in an ideal optical system, while simultaneously remaining relatively insensitive to low-spatial-frequency optical aberrations, such as tip/tilt errors, defocus, coma, astigmatism, etc. These features offer a suite of advantages for the TPF-C by relaxing many control and stability requirements, and can also provide resistance to common practical problems associated with ground-based observations; for example, telescope flexure and low-order errors left uncorrected by the AO system due to wavefront sensor-deformable mirror lag time can leak light at significant levels. Our recent lab experiments show that prototype image masks can generate contrast levels on the order of 2x10 -6 at 3 λ/D and 6x10 -7 at 10 λ/D without deformable mirror correction using monochromatic light (Crepp et al. 2006), and that this contrast is limited primarily by light scattered by imperfections in the optics and extra diffraction created by mask construction errors. These experiments also indicate that the tilt and defocus sensitivities of high-order masks follow the theoretical predictions of Shaklan and Green 2005. In this paper, we discuss these topics as well as review our progress on developing techniques for fabricating a new series of image masks that are "free-standing", as such construction designs may alleviate some of the (mostly chromatic) problems associated with masks that rely on glass substrates for mechanical support. Finally, results obtained from our AO coronagraph simulations are provided in the last section. In particular, we find that: (i) apodized masks provide deeper contrast than hard-edge masks when the image quality exceeds 80% Strehl ratio (SR), (ii) above 90% SR, 4th-order band-limited masks provide higher off-axis throughput than Gaussian masks when generating comparable contrast levels, and (iii) below ~90% SR, hard-edge masks may be better suited for high contrast imaging, since they are less susceptible to tip/tilt alignment errors.

New concept for in-line OLED manufacturing

NASA Astrophysics Data System (ADS)

Hoffmann, U.; Landgraf, H.; Campo, M.; Keller, S.; Koening, M.

2011-03-01

A new concept of a vertical In-Line deposition machine for large area white OLED production has been developed. The concept targets manufacturing on large substrates (>= Gen 4, 750 x 920 mm2) using linear deposition source achieving a total material utilization of >= 50 % and tact time down to 80 seconds. The continuously improved linear evaporation sources for the organic material achieve thickness uniformity on Gen 4 substrate of better than +/- 3 % and stable deposition rates down to less than 0.1 nm m/min and up to more than 100 nm m/min. For Lithium-Fluoride but also for other high evaporation temperature materials like Magnesium or Silver a linear source with uniformity better than +/- 3 % has been developed. For Aluminum we integrated a vertical oriented point source using wire feed to achieve high (> 150 nm m/min) and stable deposition rates. The machine concept includes a new vertical vacuum handling and alignment system for Gen 4 shadow masks. A complete alignment cycle for the mask can be done in less than one minute achieving alignment accuracy in the range of several 10 μm.

High resolution masks for ion milling pores through substrates of biological interest

NASA Technical Reports Server (NTRS)

Donovan, S. S.

1978-01-01

The feasibility was investigated of electrochemically oxidizing vapor deposited aluminum coatings to produce porous aluminum oxide coatings with submicron pore diameters and with straight channels normal to the substrate surface. Porous aluminum oxide coatings were produced from vapor deposited aluminum coatings on thin stainless steel (304), copper, Teflon (FEP) and Kapton substrates and also on pure aluminum substrates. Scanning electron microscope examination indicated that porous oxide coatings can be produced with straight channels, appropriate pore diameters and none or minimal intervening residual aluminum. The oxide coatings on the copper and Kapton substrates had the straightest channels and in general were superior to those fabricated on the other substrate materials. For oxide coatings fabricated at 600 V and 300 V, pore diameters were 0.4-0.6, and 0.3 micron with center-to-center spacing of 0.7-0.8, and 0.4 micron, respectively. Estimated direct labor and materials costs to prepare an oxide mask is anticipated to be about $4-$6 per square foot.

Defect reduction of high-density full-field patterns in jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Singh, Lovejeet; Luo, Kang; Ye, Zhengmao; Xu, Frank; Haase, Gaddi; Curran, David; LaBrake, Dwayne; Resnick, Douglas; Sreenivasan, S. V.

2011-04-01

Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Jet and Flash Imprint Lithography (J-FIL) 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 resist on the substrate. Acceptance of imprint lithography for manufacturing will require demonstration that it can attain defect levels commensurate with the defect specifications of high end memory devices. Typical defectivity targets are on the order of 0.10/cm2. This work summarizes the results of defect inspections focusing on two key defect types; random non-fill defects occurring during the resist filling process and repeater defects caused by interactions with particles on the substrate. Non-fill defectivity must always be considered within the context of process throughput. The key limiting throughput step in an imprint process is resist filling time. As a result, it is critical to characterize the filling process by measuring non-fill defectivity as a function of fill time. Repeater defects typically have two main sources; mask defects and particle related defects. Previous studies have indicated that soft particles tend to cause non-repeating defects. Hard particles, on the other hand, can cause either resist plugging or mask damage. In this work, an Imprio 500 twenty wafer per hour (wph) development tool was used to study both defect types. By carefully controlling the volume of inkjetted resist, optimizing the drop pattern and controlling the resist fluid front during spreading, fill times of 1.5 seconds were achieved with non-fill defect levels of approximately 1.2/cm2. Longevity runs were used to study repeater defects and a nickel contamination was identified as the key source of particle induced repeater defects.

Selective-area growth of GaN nanowires on SiO{sub 2}-masked Si (111) substrates by molecular beam epitaxy

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

Kruse, J. E.; Doundoulakis, G.; Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, N. Plastira 100, 70013 Heraklion

2016-06-14

We analyze a method to selectively grow straight, vertical gallium nitride nanowires by plasma-assisted molecular beam epitaxy (MBE) at sites specified by a silicon oxide mask, which is thermally grown on silicon (111) substrates and patterned by electron-beam lithography and reactive-ion etching. The investigated method requires only one single molecular beam epitaxy MBE growth process, i.e., the SiO{sub 2} mask is formed on silicon instead of on a previously grown GaN or AlN buffer layer. We present a systematic and analytical study involving various mask patterns, characterization by scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy, as well asmore » numerical simulations, to evaluate how the dimensions (window diameter and spacing) of the mask affect the distribution of the nanowires, their morphology, and alignment, as well as their photonic properties. Capabilities and limitations for this method of selective-area growth of nanowires have been identified. A window diameter less than 50 nm and a window spacing larger than 500 nm can provide single nanowire nucleation in nearly all mask windows. The results are consistent with a Ga diffusion length on the silicon dioxide surface in the order of approximately 1 μm.« less

Fabrication and Characteristics of Free Standing Shaped Pupil Masks for TPF-Coronagraph

NASA Technical Reports Server (NTRS)

Balasubramanian, Kunjithapatham; Echternach, Pierre M.; Dickie, Matthew R.; Muller, Richard E.; White, Victor E.; Hoppe, Daniel J.; Shaklan, Stuart B.; Belikov, Ruslan; Kasdin, N. Jeremy; Vanderbei, Robert J.;

Advances in maskless and mask-based optical lithography on plastic flexible substrates

NASA Astrophysics Data System (ADS)

Barbu, Ionut; Ivan, Marius G.; Giesen, Peter; Van de Moosdijk, Michel; Meinders, Erwin R.

2009-12-01

Organic flexible electronics is an emerging technology with huge potential growth in the future which is likely to open up a complete new series of potential applications such as flexible OLED-based displays, urban commercial signage, and flexible electronic paper. The transistor is the fundamental building block of all these applications. A key challenge in patterning transistors on flexible plastic substrates stems from the in-plane nonlinear deformations as a consequence of foil expansion/shrinkage, moisture uptake, baking etc. during various processing steps. Optical maskless lithography is one of the potential candidates for compensating for these foil distortions by in-situ adjustment prior to exposure of the new layer image with respect to the already patterned layers. Maskless lithography also brings the added value of reducing the cost-of-ownership related to traditional mask-based tools by eliminating the need for expensive masks. For the purpose of this paper, single-layer maskless exposures at 355 nm were performed on gold-coated poly(ethylenenaphthalate) (PEN) flexible substrates temporarily attached to rigid carriers to ensure dimensional stability during processing. Two positive photoresists were employed for this study and the results on plastic foils were benchmarked against maskless as well as mask-based (ASML PAS 5500/100D stepper) exposures on silicon wafers.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

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

Plasma-Induced, Self-Masking, One-Step Approach to an Ultrabroadband Antireflective and Superhydrophilic Subwavelength Nanostructured Fused Silica Surface.

PubMed

Ye, Xin; Shao, Ting; Sun, Laixi; Wu, Jingjun; Wang, Fengrui; He, Junhui; Jiang, Xiaodong; Wu, Wei-Dong; Zheng, Wanguo

2018-04-25

In this work, antireflective and superhydrophilic subwavelength nanostructured fused silica surfaces have been created by one-step, self-masking reactive ion etching (RIE). Bare fused silica substrates with no mask were placed in a RIE vacuum chamber, and then nanoscale fluorocarbon masks and subwavelength nanostructures (SWSs) automatically formed on these substrate after the appropriate RIE plasma process. The mechanism of plasma-induced self-masking SWS has been proposed in this paper. Plasma parameter effects on the morphology of SWS have been investigated to achieve perfect nanocone-like SWS for excellent antireflection, including process time, reactive gas, and pressure of the chamber. Optical properties, i.e., antireflection and optical scattering, were simulated by the finite difference time domain (FDTD) method. Calculated data agree well with the experiment results. The optimized SWS show ultrabroadband antireflective property (up to 99% from 500 to 1360 nm). An excellent improvement of transmission was achieved for the deep-ultraviolet (DUV) range. The proposed low-cost, highly efficient, and maskless method was applied to achieve ultrabroadband antireflective and superhydrophilic SWSs on a 100 mm optical window, which promises great potential for applications in the automotive industry, goggles, and optical devices.

Chemical Communications

DTIC Science & Technology

2012-10-26

the need for alignment. We have also demonstrated the use of this technique with various materials as masks for silk biopolymer RIE processing and a...project. The automatization of silk solution was developed. Examination of different processing conditions for the raw material showed promise for...higher durability and higher flexibility optical substrates. Progress on interfaces was solidified. The previous findings on silk -metal interfaces

Effect of Three Different Core Materials on Masking Ability of a Zirconia Ceramic.

PubMed

Tabatabaian, Farhad; Masoomi, Faeze; Namdari, Mahshid; Mahshid, Minoo

2016-09-01

Masking ability of a restorative material plays a role in hiding colored substructures; however, the masking ability of zirconia ceramic (ZRC) has not yet been clearly understood in zirconia-based restorations. This study evaluated the effect of three different core materials on masking ability of a ZRC. Ten zirconia disc samples, 0.5mm in thickness and 10mm in diameter, were fabricated. A white (W) substrate (control) and three substrates of nickel-chromium alloy (NCA), non-precious gold alloy (NPGA), and ZRC were prepared. The zirconia discs were placed on the four types of substrates for spectrophotometry. The L*, a*, and b* values of the specimens were measured by a spectrophotometer and color change (ΔE) values were calculated to determine color differences between the test and control groups and were then compared with the perceptual threshold. Randomized block ANOVA and Bonferroni test analyzed the data. A significance level of 0.05 was considered. The mean and standard deviation values of ΔE for NCA, NPGA, and ZRC groups were 10.26±2.43, 9.45±1.74, and 6.70±1.91 units, respectively. Significant differences were found in the ΔE values between ZRC and the other two experimental groups (NCA and NPGA; P<0.0001 and P=0.001, respectively). The ΔE values for the groups were more than the predetermined perceptual threshold. Within the limitations of this study, it was concluded that the tested ZRC could not well mask the examined core materials.

Engineered Metallic Nanostructures: Fabrication, Characterization, and Applications

NASA Astrophysics Data System (ADS)

Bohloul, Arash

Metallic nanostructures have garnered a great deal of attention due to their fascinating optical properties, which differ from the bulk metal. They have been proven to exceed expectations in wide variety of applications including chemical and biological sensing. Nevertheless, high-throughput and low cost nanofabrication techniques are required to implant metallic nanostructures in widespread applications. With that vision, this thesis presents a versatile and reliable method for scalable fabrication of gold nanostructures. In this approach, a plasma-treated ordered array of polystyrene nanospheres acts as an initial mask. The key step in this process is the vapor-deposition of nickel as a sacrificial mask. Thereby, gold nanostructures are directly formed on the substrate through the nickel mask. This is an easy, powerful, and straightforward method that offers several degrees of freedom to precisely control the shape and size of nanostructures. We made a library of nanostructures including gold nanocrescents, double crescents, nanorings, and nanodisks with the ability to tune the size in the range of 150 to 650 nm. The fabricated nanostructures are highly packed and uniformly cover the centimeter scale substrate. The optical properties of metallic nanostructures were extensively studied by a combination of UV-Vis-NIR and Fourier transform infrared (FTIR) spectroscopies, and correlation between optical response and geometrical parameters were investigated. In the next part of this thesis, highly sensitive surface enhanced infrared absorption (SEIRA) analysis was demonstrated on gold nanocrescent arrays. Theoretical modeling was confirmed that these substrates provide highly dense and strong hot-spots over the substrate, which is required for surface enhanced spectroscopic studies. Gold nanocrescent arrays exhibit highly tunable plasmon resonance to cover desired molecular vibrational bands. These substrates experimentally illustrated 3 orders of magnitude enhancement of IR signal over the entire substrate and up to 5 orders of magnitude enhancement on hot-spot area. Finally, we showed that fabricated substrates are completely biocompatible for growth, adhesion, and proliferation of human dermal fibroblast cells. Leveraging the capability of gold nanocrescent arrays to enhance IR signals, we developed a real time SEIRA spectroscopic technique for label-free biological cell analysis. The performance of proposed method was assessed by in situ tracking the SEIRA signal of human dermal fibroblast cells cultured on gold nanocrescent arrays.

Substrate With Low Secondary Emissions

NASA Technical Reports Server (NTRS)

Jensen, Kenneth A. (Inventor); Curren, Arthur N. (Inventor); Roman, Robert F. (Inventor)

2000-01-01

The present invention is directed to a method and apparatus for producing a highly -textured surface on a copper substrate -with only extremely small amounts of texture-inducing seeding or masking material. The texture-inducing seeding material is delivered to the copper substrate electrically switching the seeding material in and out of a circuit loop.

Analytical modeling and tolerance analysis of a linear variable filter for spectral order sorting.

PubMed

Ko, Cheng-Hao; Chang, Kuei-Ying; Huang, You-Min

2015-02-23

This paper proposes an innovative method to overcome the low production rate of current linear variable filter (LVF) fabrication. During the fabrication process, a commercial coater is combined with a local mask on a substrate. The proposed analytical thin film thickness model, which is based on the geometry of the commercial coater, is developed to more effectively calculate the profiles of LVFs. Thickness tolerance, LVF zone width, thin film layer structure, transmission spectrum and the effects of variations in critical parameters of the coater are analyzed. Profile measurements demonstrate the efficacy of local mask theory in the prediction of evaporation profiles with a high degree of accuracy.

Study of residue type defect formation mechanism and the effect of advanced defect reduction (ADR) rinse process

NASA Astrophysics Data System (ADS)

Arima, Hiroshi; Yoshida, Yuichi; Yoshihara, Kosuke; Shibata, Tsuyoshi; Kushida, Yuki; Nakagawa, Hiroki; Nishimura, Yukio; Yamaguchi, Yoshikazu

2009-03-01

Residue type defect is one of yield detractors in lithography process. It is known that occurrence of the residue type defect is dependent on resist development process and the defect is reduced by optimized rinsing condition. However, the defect formation is affected by resist materials and substrate conditions. Therefore, it is necessary to optimize the development process condition by each mask level. Those optimization steps require a large amount of time and effort. The formation mechanism is investigated from viewpoint of both material and process. The defect formation is affected by resist material types, substrate condition and development process condition (D.I.W. rinse step). Optimized resist formulation and new rinse technology significantly reduce the residue type defect.

Multi-Functional, Micro Electromechanical Silicon Carbide Accelerometer

NASA Technical Reports Server (NTRS)

Okojie, Robert S. (Inventor)

2004-01-01

A method of bulk manufacturing SiC sensors is disclosed and claimed. Materials other than SiC may be used as the substrate material. Sensors requiring that the SiC substrate be pierced are also disclosed and claimed. A process flow reversal is employed whereby the metallization is applied first before the recesses are etched into or through the wafer. Aluminum is deposited on the entire planar surface of the metallization. Photoresist is spun onto the substantially planar surface of the Aluminum which is subsequently masked (and developed and removed). Unwanted Aluminum is etched with aqueous TMAH and subsequently the metallization is dry etched. Photoresist is spun onto the still substantially planar surface of Aluminum and oxide and then masked (and developed and removed) leaving the unimidized photoresist behind. Next, ITO is applied over the still substantially planar surface of Aluminum, oxide and unimidized photoresist. Unimidized and exposed photoresist and ITO directly above it are removed with Acetone. Next, deep reactive ion etching attacks exposed oxide not protected by ITO. Finally, hot phosphoric acid removes the Al and ITO enabling wires to connect with the metallization. The back side of the SiS wafer may be also etched.

Multi-functional micro electromechanical devices and method of bulk manufacturing same

NASA Technical Reports Server (NTRS)

Okojie, Robert S. (Inventor)

2004-01-01

A method of bulk manufacturing SiC sensors is disclosed and claimed. Materials other than SiC may be used as the substrate material. Sensors requiring that the SiC substrate be pierced are also disclosed and claimed. A process flow reversal is employed whereby the metallization is applied first before the recesses are etched into or through the wafer. Aluminum is deposited on the entire planar surface of the metallization. Photoresist is spun onto the substantially planar surface of the Aluminum which is subsequently masked (and developed and removed). Unwanted Aluminum is etched with aqueous TMAH and subsequently the metallization is dry etched. Photoresist is spun onto the still substantially planar surface of Aluminum and oxide and then masked (and developed and removed) leaving the unimidized photoresist behind. Next, ITO is applied over the still substantially planar surface of Aluminum, oxide and unimidized photoresist. Unimidized and exposed photoresist and ITO directly above it are removed with Acetone. Next, deep reactive ion etching attacks exposed oxide not protected by ITO. Finally, hot phosphoric acid removes the Al and ITO enabling wires to connect with the metallization. The back side of the SiC wafer may be also be etched.

Plasma-deposited fluoropolymer film mask for local porous silicon formation

PubMed Central

2012-01-01

The study of an innovative fluoropolymer masking layer for silicon anodization is proposed. Due to its high chemical resistance to hydrofluoric acid even under anodic bias, this thin film deposited by plasma has allowed the formation of deep porous silicon regions patterned on the silicon wafer. Unlike most of other masks, fluoropolymer removal after electrochemical etching is rapid and does not alter the porous layer. Local porous regions were thus fabricated both in p+-type and low-doped n-type silicon substrates. PMID:22734507

Process for selectively patterning epitaxial film growth on a semiconductor substrate

DOEpatents

Sheldon, P.; Hayes, R.E.

1984-12-04

Disclosed is a process for selectively patterning epitaxial film growth on a semiconductor substrate. The process includes forming a masking member on the surface of the substrate, the masking member having at least two layers including a first layer disposed on the substrate and the second layer covering the first layer. A window is then opened in a selected portion of the second layer by removing that portion to expose the first layer thereunder. The first layer is then subjected to an etchant introduced through the window to dissolve the first layer a sufficient amount to expose the substrate surface directly beneath the window, the first layer being adapted to preferentially dissolve at a substantially greater rate than the second layer so as to create an overhanging ledge portion with the second layer by undercutting the edges thereof adjacent the window. The epitaxial film is then deposited on the exposed substrate surface directly beneath the window. Finally, an etchant is introduced through the window to dissolve the remainder of the first layer so as to lift-off the second layer and materials deposited thereon to fully expose the balance of the substrate surface.

Process for selectively patterning epitaxial film growth on a semiconductor substrate

DOEpatents

Sheldon, Peter; Hayes, Russell E.

1986-01-01

A process is disclosed for selectively patterning epitaxial film growth on a semiconductor substrate. The process includes forming a masking member on the surface of the substrate, the masking member having at least two layers including a first layer disposed on the substrate and the second layer covering the first layer. A window is then opened in a selected portion of the second layer by removing that portion to expose the first layer thereunder. The first layer is then subjected to an etchant introduced through the window to dissolve a sufficient amount of the first layer to expose the substrate surface directly beneath the window, the first layer being adapted to preferentially dissolve at a substantially greater rate than the second layer so as to create an overhanging ledge portion with the second layer by undercutting the edges thereof adjacent to the window. The epitaxial film is then deposited on the exposed substrate surface directly beneath the window. Finally, an etchant is introduced through the window to dissolve the remainder of the first layer so as to lift-off the second layer and materials deposited thereon to fully expose the balance of the substrate surface.

The color masking ability of a zirconia ceramic on the substrates with different values.

PubMed

Tabatabaian, Farhad; Javadi Sharif, Mahdiye; Massoumi, Farhood; Namdari, Mahshid

2017-01-01

Background. The color masking ability of a restoration plays a significant role in coveringa discolored substructure; however, this optical property of zirconia ceramics has not been clearly determined yet. The aim of this in vitro study was to evaluate the color masking ability of a zirconia ceramic on substrates with different values. Methods. Ten zirconia disk specimens,0.5 mm in thickness and 10 mm in diameter, were fabricated by a CAD/CAM system. Four substrates with different values were prepared, including: white (control), light grey, dark grey, and black. The disk specimens were placed over the substratesfor spectrophotometric measurements. A spectrophotometer measured the L * , a * , and b * color attributes of the specimens. Additionally, ΔE values were calculated to determine the color differences between each group and the control,and were then compared with the perceptional threshold of ΔE=2.6. Repeated-measures ANOVA, Bonferroni, and one-sample t-test were used to analyze data. All the tests were carried out at 0.05 level of significance. Results. The means and standard deviations of ΔE values for the three groups of light grey, dark grey and black were 9.94±2.11, 10.40±2.09, and 13.34±1.77 units, respectively.Significant differences were detected between the groups in the ΔE values (P<0.0001).The ΔE values in all the groups were more than the predetermined perceptional threshold(ΔE>2.6) (P<0.0001). Conclusion. Within the limitations of this study, it was concluded that the tested zirconia ceramic did not exhibit sufficient color masking ability to hide the grey and black substrates.

Method and Apparatus for Producing a Substrate with Low Secondary Electron Emissions

NASA Technical Reports Server (NTRS)

Jensen, Kenneth A. (Inventor); Curren, Arthur N. (Inventor); Roman, Robert F. (Inventor)

1998-01-01

The present invention is directed to a method and apparatus for producing a highly-textured surface on a copper substrate with only extremely small amounts of texture-inducing seeding of masking material. The texture-inducing seeding material is delivered to the copper substrate electrically switching the seeding material in and out of a circuit loop.

VUV lithography

DOEpatents

George, Edward V.; Oster, Yale; Mundinger, David C.

1990-01-01

Deep UV projection lithography can be performed using an e-beam pumped solid excimer UV source, a mask, and a UV reduction camera. The UV source produces deep UV radiation in the range 1700-1300A using xenon, krypton or argon; shorter wavelengths of 850-650A can be obtained using neon or helium. A thin solid layer of the gas is formed on a cryogenically cooled plate and bombarded with an e-beam to cause fluorescence. The UV reduction camera utilizes multilayer mirrors having high reflectivity at the UV wavelength and images the mask onto a resist coated substrate at a preselected demagnification. The mask can be formed integrally with the source as an emitting mask.

Masking technique for coating thickness control on large and strongly curved aspherical optics.

PubMed

Sassolas, B; Flaminio, R; Franc, J; Michel, C; Montorio, J-L; Morgado, N; Pinard, L

2009-07-01

We discuss a method to control the coating thickness deposited onto large and strongly curved optics by ion beam sputtering. The technique uses an original design of the mask used to screen part of the sputtered materials. A first multielement mask is calculated from the measured two-dimensional coating thickness distribution. Then, by means of an iterative process, the final mask is designed. By using such a technique, it has been possible to deposit layers of tantalum pentoxide having a high thickness gradient onto a curved substrate 500 mm in diameter. Residual errors in the coating thickness profile are below 0.7%.

Dislocation Reduction and Stress Relaxation of GaN and InGaN Multiple Quantum Wells with Improved Performance via Serpentine Channel Patterned Mask.

PubMed

Ji, Qingbin; Li, Lei; Zhang, Wei; Wang, Jia; Liu, Peichi; Xie, Yahong; Yan, Tongxing; Yang, Wei; Chen, Weihua; Hu, Xiaodong

2016-08-24

The existence of high threading dislocation density (TDD) in GaN-based epilayers is a long unsolved problem, which hinders further applications of defect-sensitive GaN-based devices. Multiple-modulation of epitaxial lateral overgrowth (ELOG) is used to achieve high-quality GaN template on a novel serpentine channel patterned sapphire substrate (SCPSS). The dislocation blocking brought by the serpentine channel patterned mask, coupled with repeated dislocation bending, can reduce the dislocation density to a yet-to-be-optimized level of ∼2 × 10(5) to 2 × 10(6) cm(-2). About 80% area utilization rate of GaN with low TDD and stress relaxation is obtained. The periodical variations of dislocation density, optical properties and residual stress in GaN-based epilayers on SCPSS are analyzed. The quantum efficiency of InGaN/GaN multiple quantum wells (MQWs) on it can be increased by 52% compared with the conventional sapphire substrate. The reduced nonradiative recombination centers, the enhanced carrier localization, and the suppressed quantum confined Stark effect, are the main determinants of improved luminous performance in MQWs on SCPSS. This developed ELOG on serpentine shaped mask needs no interruption and regrowth, which can be a promising candidate for the heteroepitaxy of semipolar/nonpolar GaN and GaAs with high quality.

Humidity Sensing Properties of Paper Substrates and Their Passivation with ZnO Nanoparticles for Sensor Applications

PubMed Central

Niarchos, Georgios; Dubourg, Georges; Afroudakis, Georgios; Georgopoulos, Markos; Tsouti, Vasiliki; Makarona, Eleni; Crnojevic-Bengin, Vesna; Tsamis, Christos

2017-01-01

In this paper, we investigated the effect of humidity on paper substrates and propose a simple and low-cost method for their passivation using ZnO nanoparticles. To this end, we built paper-based microdevices based on an interdigitated electrode (IDE) configuration by means of a mask-less laser patterning method on simple commercial printing papers. Initial resistive measurements indicate that a paper substrate with a porous surface can be used as a cost-effective, sensitive and disposable humidity sensor in the 20% to 70% relative humidity (RH) range. Successive spin-coated layers of ZnO nanoparticles then, control the effect of humidity. Using this approach, the sensors become passive to relative humidity changes, paving the way to the development of ZnO-based gas sensors on paper substrates insensitive to humidity. PMID:28273847

Digital selective growth of a ZnO nanowire array by large scale laser decomposition of zinc acetate.

PubMed

Hong, Sukjoon; Yeo, Junyeob; Manorotkul, Wanit; Kang, Hyun Wook; Lee, Jinhwan; Han, Seungyong; Rho, Yoonsoo; Suh, Young Duk; Sung, Hyung Jin; Ko, Seung Hwan

2013-05-07

We develop a digital direct writing method for ZnO NW micro-patterned growth on a large scale by selective laser decomposition of zinc acetate. For ZnO NW growth, by replacing the bulk heating with the scanning focused laser as a fully digital local heat source, zinc acetate crystallites can be selectively activated as a ZnO seed pattern to grow ZnO nanowires locally on a larger area. Together with the selective laser sintering process of metal nanoparticles, more than 10,000 UV sensors have been demonstrated on a 4 cm × 4 cm glass substrate to develop all-solution processible, all-laser mask-less digital fabrication of electronic devices including active layer and metal electrodes without any conventional vacuum deposition, photolithographic process, premade mask, high temperature and vacuum environment.

X-ray/VUV transmission gratings for astrophysical and laboratory applications

NASA Technical Reports Server (NTRS)

Schattenburg, M. L.; Anderson, E. H.; Smith, Henry I.

1990-01-01

This paper describes the techniques used to fabricate deep-submicron-period transmission gratings for astrophysical and laboratory applications, with special attention given to the major steps involved in the transmission grating fabrication. These include the holographic lithography procedure used to pattern the master transmission grating, the fabrication of X-ray mask, the X-ray lithography step used to transfer the X-ray mask pattern into a substrate, and the electroplating of the substrate to form the final grating pattern. The various ways in which transmission gratings can be used in X-ray and VUV spectroscopy are discussed together with some examples of experiments reported in the literature.

Micromachined microwave signal control device and method for making same

DOEpatents

Forman, Michael A [San Francisco, CA

2008-09-02

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

Method for making a micromachined microwave signal control device

DOEpatents

Forman, Michael A [Mountain House, CA

2011-02-15

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

Critical aspects of substrate nanopatterning for the ordered growth of GaN nanocolumns.

PubMed

Barbagini, Francesca; Bengoechea-Encabo, Ana; Albert, Steven; Martinez, Javier; Sanchez García, Miguel Angel; Trampert, Achim; Calleja, Enrique

2011-12-14

Precise and reproducible surface nanopatterning is the key for a successful ordered growth of GaN nanocolumns. In this work, we point out the main technological issues related to the patterning process, mainly surface roughness and cleaning, and mask adhesion to the substrate. We found that each of these factors, process-related, has a dramatic impact on the subsequent selective growth of the columns inside the patterned holes. We compare the performance of e-beam lithography, colloidal lithography, and focused ion beam in the fabrication of hole-patterned masks for ordered columnar growth. These results are applicable to the ordered growth of nanocolumns of different materials.

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.

VUV lithography

DOEpatents

George, E.V.; Oster, Y.; Mundinger, D.C.

1990-12-25

Deep UV projection lithography can be performed using an e-beam pumped solid excimer UV source, a mask, and a UV reduction camera. The UV source produces deep UV radiation in the range 1,700--1,300A using xenon, krypton or argon; shorter wavelengths of 850--650A can be obtained using neon or helium. A thin solid layer of the gas is formed on a cryogenically cooled plate and bombarded with an e-beam to cause fluorescence. The UV reduction camera utilizes multilayer mirrors having high reflectivity at the UV wavelength and images the mask onto a resist coated substrate at a preselected demagnification. The mask can be formed integrally with the source as an emitting mask. 6 figs.

Nanotip Carpets as Antireflection Surfaces

NASA Technical Reports Server (NTRS)

Bae, Youngsam; Mobasser, Sohrab; Manohara, Harish; Lee, Choonsup

2008-01-01

Carpet-like random arrays of metal-coated silicon nanotips have been shown to be effective as antireflection surfaces. Now undergoing development for incorporation into Sun sensors that would provide guidance for robotic exploratory vehicles on Mars, nanotip carpets of this type could also have many uses on Earth as antireflection surfaces in instruments that handle or detect ultraviolet, visible, or infrared light. In the original Sun-sensor application, what is required is an array of 50-micron-diameter apertures on what is otherwise an opaque, minimally reflective surface, as needed to implement a miniature multiple-pinhole camera. The process for fabrication of an antireflection nanotip carpet for this application (see Figure 1) includes, and goes somewhat beyond, the process described in A New Process for Fabricating Random Silicon Nanotips (NPO-40123), NASA Tech Briefs, Vol. 28, No. 1 (November 2004), page 62. In the first step, which is not part of the previously reported process, photolithography is performed to deposit etch masks to define the 50-micron apertures on a silicon substrate. In the second step, which is part of the previously reported process, the non-masked silicon area between the apertures is subjected to reactive ion etching (RIE) under a special combination of conditions that results in the growth of fluorine-based compounds in randomly distributed formations, known in the art as "polymer RIE grass," that have dimensions of the order of microns. The polymer RIE grass formations serve as microscopic etch masks during the next step, in which deep reactive ion etching (DRIE) is performed. What remains after DRIE is the carpet of nano - tips, which are high-aspect-ratio peaks, the tips of which have radii of the order of nanometers. Next, the nanotip array is evaporatively coated with Cr/Au to enhance the absorption of light (more specifically, infrared light in the Sun-sensor application). The photoresist etch masks protecting the apertures are then removed by dipping the substrate into acetone. Finally, for the Sun-sensor application, the back surface of the substrate is coated with a 57-nm-thick layer of Cr for attenuation of sunlight.

Reconfigurable mask for adaptive coded aperture imaging (ACAI) based on an addressable MOEMS microshutter array

NASA Astrophysics Data System (ADS)

McNie, Mark E.; Combes, David J.; Smith, Gilbert W.; Price, Nicola; Ridley, Kevin D.; Brunson, Kevin M.; Lewis, Keith L.; Slinger, Chris W.; Rogers, Stanley

2007-09-01

Coded aperture imaging has been used for astronomical applications for several years. Typical implementations use a fixed mask pattern and are designed to operate in the X-Ray or gamma ray bands. More recent applications have emerged in the visible and infra red bands for low cost lens-less imaging systems. System studies have shown that considerable advantages in image resolution may accrue from the use of multiple different images of the same scene - requiring a reconfigurable mask. We report on work to develop a novel, reconfigurable mask based on micro-opto-electro-mechanical systems (MOEMS) technology employing interference effects to modulate incident light in the mid-IR band (3-5μm). This is achieved by tuning a large array of asymmetric Fabry-Perot cavities by applying an electrostatic force to adjust the gap between a moveable upper polysilicon mirror plate supported on suspensions and underlying fixed (electrode) layers on a silicon substrate. A key advantage of the modulator technology developed is that it is transmissive and high speed (e.g. 100kHz) - allowing simpler imaging system configurations. It is also realised using a modified standard polysilicon surface micromachining process (i.e. MUMPS-like) that is widely available and hence should have a low production cost in volume. We have developed designs capable of operating across the entire mid-IR band with peak transmissions approaching 100% and high contrast. By using a pixelated array of small mirrors, a large area device comprising individually addressable elements may be realised that allows reconfiguring of the whole mask at speeds in excess of video frame rates.

Method for etching thin films of niboium and niobium-containing compounds for preparing superconductive circuits

DOEpatents

Kampwirth, R.T.; Schuller, I.K.; Falco, C.M.

1979-11-23

An improved method of preparing thin film superconducting electrical circuits of niobium or niobium compounds is provided in which a thin film of the niobium or niobium compound is applied to a nonconductive substrate and covered with a layer of photosensitive material. The sensitive material is in turn covered with a circuit pattern exposed and developed to form a mask of the circuit in photoresistive material on the surface of the film. The unmasked excess niobium film is removed by contacting the substrate with an aqueous etching solution of nitric acid, sulfuric acid, and hydrogen fluoride, which will rapidly etch the niobium compound without undercutting the photoresist. A modification of the etching solution will permit thin films to be lifted from the substrate without further etching.

Reusable High Aspect Ratio 3-D Nickel Shadow Mask

PubMed Central

Shandhi, M.M.H.; Leber, M.; Hogan, A.; Warren, D.J.; Bhandari, R.; Negi, S.

2017-01-01

Shadow Mask technology has been used over the years for resistless patterning and to pattern on unconventional surfaces, fragile substrate and biomaterial. In this work, we are presenting a novel method to fabricate high aspect ratio (15:1) three-dimensional (3D) Nickel (Ni) shadow mask with vertical pattern length and width of 1.2 mm and 40 μm respectively. The Ni shadow mask is 1.5 mm tall and 100 μm wide at the base. The aspect ratio of the shadow mask is 15. Ni shadow mask is mechanically robust and hence easy to handle. It is also reusable and used to pattern the sidewalls of unconventional and complex 3D geometries such as microneedles or neural electrodes (such as the Utah array). The standard Utah array has 100 active sites at the tip of the shaft. Using the proposed high aspect ratio Ni shadow mask, the Utah array can accommodate 300 active sites, 200 of which will be along and around the shaft. The robust Ni shadow mask is fabricated using laser patterning and electroplating techniques. The use of Ni 3D shadow mask will lower the fabrication cost, complexity and time for patterning out-of-plane structures. PMID:29056835

Surface texturing of fluoropolymers

NASA Technical Reports Server (NTRS)

Banks, B. A.; Mirtich, M. J.; Sovey, J. S. (Inventor)

1982-01-01

A method is disclosed for improving surface texture for adhesive bonding, metal bonding, substrate plating, decal substrate preparation, and biomedical implant applications. The surface to be bonded is dusted in a controlled fashion to produce a disbursed layer of fine mesh particles which serve as masks. The surface texture is produced by impinging gas ions on the masked surface. The textured surface takes the form of pillars or cones. The bonding material, such as a liquid epoxy, flows between the pillars which results in a bond having increased strength. For bonding metals a thin film of metal is vapor or sputter deposited onto the textured surface. Electroplating or electroless plating is then used to increase the metal thickness in the desired amount.

Critical aspects of substrate nanopatterning for the ordered growth of GaN nanocolumns

PubMed Central

2011-01-01

Precise and reproducible surface nanopatterning is the key for a successful ordered growth of GaN nanocolumns. In this work, we point out the main technological issues related to the patterning process, mainly surface roughness and cleaning, and mask adhesion to the substrate. We found that each of these factors, process-related, has a dramatic impact on the subsequent selective growth of the columns inside the patterned holes. We compare the performance of e-beam lithography, colloidal lithography, and focused ion beam in the fabrication of hole-patterned masks for ordered columnar growth. These results are applicable to the ordered growth of nanocolumns of different materials. PMID:22168918

Fabrication of a terahertz quantum-cascade laser with a double metal waveguide based on multilayer GaAs/AlGaAs heterostructures

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

Khabibullin, R. A., E-mail: khabibullin@isvch.ru; Shchavruk, N. V.; Pavlov, A. Yu.

2016-10-15

The Postgrowth processing of GaAs/AlGaAs multilayer heterostructures for terahertz quantumcascade lasers (QCLs) are studied. This procedure includes the thermocompression bonding of In–Au multilayer heterostructures with a doped n{sup +}-GaAs substrate, mechanical grinding, and selective wet etching of the substrate, and dry etching of QCL ridge mesastripes through a Ti/Au metallization mask 50 and 100 μm wide. Reactive-ion-etching modes with an inductively coupled plasma source in a BCl{sub 3}/Ar gas mixture are selected to obtain vertical walls of the QCL ridge mesastripes with minimum Ti/Au mask sputtering.

Enhancing the Microparticle Deposition Stability and Homogeneity on Planer for Synthesis of Self-Assembly Monolayer.

PubMed

Shih, An-Ci; Han, Chi-Jui; Kuo, Tsung-Cheng; Cheng, Yun-Chien

2018-03-14

The deposition stability and homogeneity of microparticles improved with mask, lengthened nozzle and flow rate adjustment. The microparticles can be used to encapsulate monomers, before the monomers in the microparticles can be deposited onto a substrate for nanoscale self-assembly. For the uniformity of the synthesized nanofilm, the homogeneity of the deposited microparticles becomes an important issue. Based on the ANSYS simulation results, the effects of secondary flow were minimized with a lengthened nozzle. The ANSYS simulation was also used to investigate the ring-vortex generation and why the ring vortex can be eliminated by adding a mask with an aperture between the nozzle and deposition substrate. The experimental results also showed that particle deposition with a lengthened nozzle was more stable, while adding the mask stabilized deposition and diminished the ring-vortex contamination. The effects of flow rate and pressure were also investigated. Hence, the deposition stability and homogeneity of microparticles was improved.

High aspect ratio nano-fabrication of photonic crystal structures on glass wafers using chrome as hard mask.

PubMed

Hossain, Md Nazmul; Justice, John; Lovera, Pierre; McCarthy, Brendan; O'Riordan, Alan; Corbett, Brian

2014-09-05

Wafer-scale nano-fabrication of silicon nitride (Si x N y ) photonic crystal (PhC) structures on glass (quartz) substrates is demonstrated using a thin (30 nm) chromium (Cr) layer as the hard mask for transferring the electron beam lithography (EBL) defined resist patterns. The use of the thin Cr layer not only solves the charging effect during the EBL on the insulating substrate, but also facilitates high aspect ratio PhCs by acting as a hard mask while deep etching into the Si x N y . A very high aspect ratio of 10:1 on a 60 nm wide grating structure has been achieved while preserving the quality of the flat top of the narrow lines. The presented nano-fabrication method provides PhC structures necessary for a high quality optical response. Finally, we fabricated a refractive index based PhC sensor which shows a sensitivity of 185 nm per RIU.

2D mesoscale colloidal crystal patterns on polymer substrates

NASA Astrophysics Data System (ADS)

Bredikhin, Vladimir; Bityurin, Nikita

2018-05-01

The development of nanosphere lithography relies on the ability of depositing 2D colloidal crystals comprising micro- and nano-size elements on substrates of different materials. One of the most difficult problems here is deposition of coatings on hydrophobic substrates, e.g. polymers, from aqueous colloidal solutions. We use UV photooxidation for substrate hydrophilization. We demonstrate a new method of producing a two-dimensional ordered array of polymer microparticles (polystyrene microspheres ∼1 μm in diameter) on a polymer substrate (PMMA). We show that implementation of the new deposition technique for directed self-assembly of microspheres on an UV irradiated surface provides an opportunity to obtain coatings on a hydrophilized PMMA surface of large area (∼5 cm2). UV irradiation of the surface through masks allows creating 2D patterns consisting of mesoscale elements formed by the deposited self-assembled microparticles owing to the fact that the colloidal particles are deposited only on the irradiated area leaving the non-irradiated sections intact.

Single closed contact for 0.18-micron photolithography process

NASA Astrophysics Data System (ADS)

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

2000-06-01

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

Defect reduction for semiconductor memory applications using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Ye, Zhengmao; Luo, Kang; Irving, J. W.; Lu, Xiaoming; Zhang, Wei; Fletcher, Brian; Liu, Weijun; Xu, Frank; LaBrake, Dwayne; Resnick, Douglas; Sreenivasan, S. V.

2013-03-01

Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Jet and Flash Imprint Lithography (J-FIL) 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 resist on the substrate. Acceptance of imprint lithography for manufacturing will require demonstration that it can attain defect levels commensurate with the defect specifications of high end memory devices. Typical defectivity targets are on the order of 0.10/cm2. In previous studies, we have focused on defects such as random non-fill defects occurring during the resist filling process and repeater defects caused by interactions with particles on the substrate. In this work, we attempted to identify the critical imprint defect types using a mask with NAND Flash-like patterns at dimensions as small as 26nm. The two key defect types identified were line break defects induced by small particulates and airborne contaminants which result in local adhesion failure. After identification, the root cause of the defect was determined, and corrective measures were taken to either eliminate or reduce the defect source. As a result, we have been able to reduce defectivity levels by more than three orders of magnitude in only 12 months and are now achieving defectivity adders as small as 2 adders per lot of wafers.

Silicon Solar Cell Optimization.

DTIC Science & Technology

1981-06-01

from the surface. (b) Oxide mask formation Etching grooves into the silicon requires an effective alkaline-resistant mask which will withstand the...face. This technique employs a very viscous photoresist, Furt #206, in conjunction with multiple spin-applications and bake periods, to effectively ...175 80 125 78 75 74 To compare the effects of groove depth, substrate thick- ness and bulk resistivity, an experiment was conducted. Using identical

Fabrication of 3D surface structures using grayscale lithography

NASA Astrophysics Data System (ADS)

Stilson, Christopher; Pal, Rajan; Coutu, Ronald A.

2014-03-01

The ability to design and develop 3D microstructures is important for microelectromechanical systems (MEMS) fabrication. Previous techniques used to create 3D devices included tedious steps in direct writing and aligning patterns onto a substrate followed by multiple photolithography steps using expensive, customized equipment. Additionally, these techniques restricted batch processing and placed limits on achievable shapes. Gray-scale lithography enables the fabrication of a variety of shapes using a single photolithography step followed by reactive ion etching (RIE). Micromachining 3D silicon structures for MEMS can be accomplished using gray-scale lithography along with dry anisotropic etching. In this study, we investigated: using MATLAB for mask designs; feasibility of using 1 μm Heidelberg mask maker to direct write patterns onto photoresist; using RIE processing to etch patterns into a silicon substrate; and the ability to tailor etch selectivity for precise fabrication. To determine etch rates and to obtain desired etch selectivity, parameters such as gas mixture, gas flow, and electrode power were studied. This process successfully demonstrates the ability to use gray-scale lithography and RIE for use in the study of micro-contacts. These results were used to produce a known engineered non-planer surface for testing micro-contacts. Surface structures are between 5 μm and 20 μm wide with varying depths and slopes based on mask design and etch rate selectivity. The engineered surfaces will provide more insight into contact geometries and failure modes of fixed-fixed micro-contacts.

Effective formation method for an aspherical microlens array based on an aperiodic moving mask during exposure.

PubMed

Shi, Lifang; Du, Chunlei; Dong, Xiaochun; Deng, Qiling; Luo, Xiangang

2007-12-01

An aperiodic mask design method for fabricating a microlens array with an aspherical profile is proposed. The nonlinear relationship between exposure doses and lens profile is considered, and the select criteria of quantization interval and fabrication range of the method are given. The mask function of a quadrangle microlens array with a hyperboloid profile used in the infrared was constructed by using this method. The microlens array can be effectively fabricated during a one time exposure process using the mask. Reactive ion etching was carried out to transfer the structure into the substrate of germanium. The measurement results indicate that the roughness is less than 10 nm (pv), and the profile error is less than 40 nm (rms).

Selective nanoscale growth of lattice mismatched materials

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

Lee, Seung-Chang; Brueck, Steven R. J.

Exemplary embodiments provide materials and methods of forming high-quality semiconductor devices using lattice-mismatched materials. In one embodiment, a composite film including one or more substantially-single-particle-thick nanoparticle layers can be deposited over a substrate as a nanoscale selective growth mask for epitaxially growing lattice-mismatched materials over the substrate.

Systems and methods for the combinatorial synthesis of novel materials

DOEpatents

Wu, Xin Di; Wang, Youqi; Goldwasser, Isy

2000-01-01

Methods and apparatus for the preparation of a substrate having an array of diverse materials in predefined regions thereon. A substrate having an array of diverse materials thereon is generally prepared by depositing components of target materials to predefined regions on the substrate, and, in some embodiments, simultaneously reacting the components to form at least two resulting materials. In particular, the present invention provides novel masking systems and methods for applying components of target materials onto a substrate in a combinatorial fashion, thus creating arrays of resulting materials that differ slightly in composition, stoichiometry, and/or thickness. Using the novel masking systems of the present invention, components can be delivered to each site in a uniform distribution, or in a gradient of stoichiometries, thicknesses, compositions, etc. Resulting materials which can be prepared using the methods and apparatus of the present invention include, for example, covalent network solids, ionic solids and molecular solids. Once prepared, these resulting materials can be screened sequentially, or in parallel, for useful properties including, for example, electrical, thermal, mechanical, morphological, optical, magnetic, chemical and other properties.

Photolithography-free laser-patterned HF acid-resistant chromium-polyimide mask for rapid fabrication of microfluidic systems in glass

NASA Astrophysics Data System (ADS)

Zamuruyev, Konstantin O.; Zrodnikov, Yuriy; Davis, Cristina E.

2017-01-01

Excellent chemical and physical properties of glass, over a range of operating conditions, make it a preferred material for chemical detection systems in analytical chemistry, biology, and the environmental sciences. However, it is often compromised with SU8, PDMS, or Parylene materials due to the sophisticated mask preparation requirements for wet etching of glass. Here, we report our efforts toward developing a photolithography-free laser-patterned hydrofluoric acid-resistant chromium-polyimide tape mask for rapid prototyping of microfluidic systems in glass. The patterns are defined in masking layer with a diode-pumped solid-state laser. Minimum feature size is limited to the diameter of the laser beam, 30 µm minimum spacing between features is limited by the thermal shrinkage and adhesive contact of the polyimide tape to 40 µm. The patterned glass substrates are etched in 49% hydrofluoric acid at ambient temperature with soft agitation (in time increments, up to 60 min duration). In spite of the simplicity, our method demonstrates comparable results to the other current more sophisticated masking methods in terms of the etched depth (up to 300 µm in borosilicate glass), feature under etch ratio in isotropic etch (~1.36), and low mask hole density. The method demonstrates high yield and reliability. To our knowledge, this method is the first proposed technique for rapid prototyping of microfluidic systems in glass with such high performance parameters. The proposed method of fabrication can potentially be implemented in research institutions without access to a standard clean-room facility.

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

NASA Astrophysics Data System (ADS)

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

2016-02-01

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

Cyclic photochemical re-growth of gold nanoparticles: Overcoming the mask-erosion limit during reactive ion etching on the nanoscale

PubMed Central

Seidenstücker, Axel; Plettl, Alfred; Ziemann, Paul

2013-01-01

Summary The basic idea of using hexagonally ordered arrays of Au nanoparticles (NP) on top of a given substrate as a mask for the subsequent anisotropic etching in order to fabricate correspondingly ordered arrays of nanopillars meets two serious obstacles: The position of the NP may change during the etching process and, thus, the primary pattern of the mask deteriorates or is completely lost. Furthermore, the NP are significantly eroded during etching and, consequently, the achievable pillar height is strongly restricted. The present work presents approaches on how to get around both problems. For this purpose, arrays of Au NPs (starting diameter 12 nm) are deposited on top of silica substrates by applying diblock copolymer micelle nanolithography (BCML). It is demonstrated that evaporated octadecyltrimethoxysilane (OTMS) layers act as stabilizer on the NP position, which allows for an increase of their size up to 50 nm by an electroless photochemical process. In this way, ordered arrays of silica nanopillars are obtained with maximum heights of 270 nm and aspect ratios of 5:1. Alternatively, the NP position can be fixed by a short etching step with negligible mask erosion followed by cycles of growing and reactive ion etching (RIE). In that case, each cycle is started by photochemically re-growing the Au NP mask and thereby completely compensating for the erosion due to the previous cycle. As a result of this mask repair method, arrays of silica nanopillar with heights up to 680 nm and aspect ratios of 10:1 are fabricated. Based on the given recipes, the approach can be applied to a variety of materials like silicon, silicon oxide, and silicon nitride. PMID:24367758

Ultrasonic generator and detector using an optical mask having a grating for launching a plurality of spatially distributed, time varying strain pulses in a sample

DOEpatents

Maris, Humphrey J.

2003-01-01

A method and a system are disclosed for determining at least one characteristic of a sample that contains a substrate and at least one film disposed on or over a surface of the substrate. The method includes a first step of placing a mask over a free surface of the at least one film, where the mask has a top surface and a bottom surface that is placed adjacent to the free surface of the film. The bottom surface of the mask has formed therein or thereon a plurality of features for forming at least one grating. A next step directs optical pump pulses through the mask to the free surface of the film, where individual ones of the pump pulses are followed by at least one optical probe pulse. The pump pulses are spatially distributed by the grating for launching a plurality of spatially distributed, time varying strain pulses within the film, which cause a detectable change in optical constants of the film. A next step detects a reflected or a transmitted portion of the probe pulses, which are also spatially distributed by the grating. A next step measures a change in at least one characteristic of at least one of reflected or transmitted probe pulses due to the change in optical constants, and a further step determines the at least one characteristic of the sample from the measured change in the at least one characteristic of the probe pulses. An optical mask is also disclosed herein, and forms a part of these teachings.

Ultrasonic generator and detector using an optical mask having a grating for launching a plurality of spatially distributed, time varying strain pulses in a sample

DOEpatents

Maris, Humphrey J.

2002-01-01

A method and a system are disclosed for determining at least one characteristic of a sample that contains a substrate and at least one film disposed on or over a surface of the substrate. The method includes a first step of placing a mask over a free surface of the at least one film, where the mask has a top surface and a bottom surface that is placed adjacent to the free surface of the film. The bottom surface of the mask has formed therein or thereon a plurality of features for forming at least one grating. A next step directs optical pump pulses through the mask to the free surface of the film, where individual ones of the pump pulses are followed by at least one optical probe pulse. The pump pulses are spatially distributed by the grating for launching a plurality of spatially distributed, time varying strain pulses within the film, which cause a detectable change in optical constants of the film. A next step detects a reflected or a transmitted portion of the probe pulses, which are also spatially distributed by the grating. A next step measures a change in at least one characteristic of at least one of reflected or transmitted probe pulses due to the change in optical constants, and a further step determines the at least one characteristic of the sample from the measured change in the at least one characteristic of the probe pulses. An optical mask is also disclosed herein, and forms a part of these teachings.

Method of patterning an aerogel

DOEpatents

Reed, Scott T [Edgewood, NM

2012-07-24

A method for producing a pattern in an aerogel disposed as a coating on a substrate comprises exposing the aerogel coating to the vapors of a hydrophobic silane compound, masking the aerogel coating with a shadow photomask and irradiating the aerogel coating with ultraviolet (UV) irradiation. The exposure to UV through the shadow mask creates a pattern of hydrophobic and hydrophilic regions in the aerogel coating. Etching away the hydrophilic regions of the aerogel coating, preferably with a 1 molar solution of sodium hydroxide, leaves the unwetted and unetched hydrophobic regions of the aerogel layer on the substrate, replicating the pattern of the photomask. The hydrophobic aerogel pattern can be further exposed to UV irradiation if desired, to create a hydrophilic aerogel pattern.

Clean induced feature CD shift of EUV mask

NASA Astrophysics Data System (ADS)

Nesládek, Pavel; Schedel, Thorsten; Bender, Markus

2016-05-01

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

Fabrication of 0.25-um electrode width SAW filters using x-ray lithography with a laser plasma source

NASA Astrophysics Data System (ADS)

Bobkowski, Romuald; Li, Yunlei; Fedosejevs, Robert; Broughton, James N.

1996-05-01

A process for the fabrication of surface acoustic wave (SAW) devices with line widths of 250 nm and less, based on x-ray lithography using a laser-plasma source has been developed. The x-ray lithography process is based on keV x-ray emission from Cu plasma produced by 15 Hz, 50 ps, 248 nm KrF excimer laser pulses. The full structure of a 2 GHz surface acoustic wave filter with interdigital transducers in a split-electrode geometry has been manufactured. The devices require patterning a 150 nm thick aluminum layer on a LiNbO3 substrate with electrodes 250 nm wide. The manufacturing process has two main steps: x-ray mask fabrication employing e-beam lithography and x-ray lithography to obtain the final device. The x-ray masks are fabricated on 1 micrometers thick membranes of Si2N4. The line patterns on the masks are written into PMMA resist using a scanning electron microscope which has been interfaced to a personal computer equipped to control the x and y scan voltages. The opaque regions of the x-ray mask are then formed by electroplating fine grain gold into the open spaces in the etched PMMA. The mask and sample are mounted in an exposure cassette with a fixed spacer of 10 micrometers separating them. The sample consists of a LiNbO3 substrate coated with Shipley XP90104C x-ray resist which has been previously characterized. The x-ray patterning is carried out in an exposure chamber with flowing helium background gas in order to minimize debris deposition on the filters. After etching the x-ray resist, the final patterns are produced using metallization and a standard lift-off technique. The SAW filters are then bonded and packaged onto impedance matching striplines. The resultant devices are tested using Scalar Network Analyzers. The final devices produced had a center frequency of 1.93 GHz with a bandwidth of 98 MHz, close to the expected performance of our simple design.

A facile and cost-effective TEM grid approach to design gold nano-structured substrates for high throughput plasmonic sensitive detection of biomolecules.

PubMed

Jia, Kun; Bijeon, Jean Louis; Adam, Pierre Michel; Ionescu, Rodica Elena

2013-02-21

A commercial TEM grid was used as a mask for the creation of extremely well-organized gold micro-/nano-structures on a glass substrate via a high temperature annealing process at 500 °C. The structured substrate was (bio)functionalized and used for the high throughput LSPR immunosensing of different concentrations of a model protein named bovine serum albumin.

Electrically induced formation of uncapped, hollow polymeric microstructures

NASA Astrophysics Data System (ADS)

Lee, Sung Hun; Kim, Pilnam; Jeong, Hoon Eui; Suh, Kahp Y.

2006-11-01

Uncapped, hollow polymeric microstructures were fabricated on a silicon substrate using electric field induced stretching and detachment. Initially, square or cylinder microposts were generated using a solvent-assisted capillary molding technique, and a featureless electrode mask was positioned on the top of the microstructure with spacers maintaining an air gap (~20 µm). Upon exposure to an external electric field (1.0-3.0 V µm-1), the hollow microstructures were destabilized and stretched by the well-known electrohydrodynamic instability, resulting in contact of the top polymer surface with the mask. Subsequently, detachment of the capping layer occurred upon removal of the mask due to larger adhesion forces at the polymer/mask interface than cohesion forces of the polymer. These hollow microstructures were tested to capture the budding yeast, Saccharomyces cerevisiae, for shear protection.

EUV phase-shifting masks and aberration monitors

NASA Astrophysics Data System (ADS)

Deng, Yunfei; Neureuther, Andrew R.

2002-07-01

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

Scanning nozzle plating system. [for etching or plating metals on substrates without masking

NASA Technical Reports Server (NTRS)

Oliver, G. D. (Inventor)

1974-01-01

A plating system is described in which a substrate to be plated is supported on a stationary platform. A nozzle assembly with a small nozzle is supplied with a plating solution under high pressure, so that a constant-flow stream of solution is directed to the substrate. The nozzle assembly is moved relative to the substrate at a selected rate and movement pattern. A potential difference (voltage) is provided between the substrate and the solution in the assembly. The voltage amplitude is modulated so that only when the amplitude is above a minimum known value plating takes place.

Method for masking selected regions of a substrate

DOEpatents

Fusaro, Jr., Robert Anthony; Bethel, Timothy Francis

2010-05-04

Described herein is a method for providing a clean edge at the interface of a portion of a substrate coated with a coating system and an adjacent portion of the substrate which is uncoated. The method includes the step of forming a zone of non-adherence on the substrate portion which is to be uncoated, prior to application of the coating system. The zone of non-adherence is adjacent the interface, so that the coating system will not adhere to the zone of non-adherence, but will adhere to the portion of the substrate which is to be coated with the coating system.

Method for correcting imperfections on a surface

DOEpatents

Sweatt, William C.; Weed, John W.

1999-09-07

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

Ion Beam Etching: Replication of Micro Nano-structured 3D Stencil Masks

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

Weber, Patrick; Guibert, Edouard; Mikhailov, Serguei

2009-03-10

Ion beam LIGA allows the etching of 3D nano-structures by direct writing with a nano-sized beam. However, this is a relatively time consuming process. We propose here another approach for etching structures on large surfaces and faster, compared to the direct writing process. This approach consists of replicating 3D structured masks, by scanning an unfocused ion beam. A polymer substrate is placed behind the mask, as in UV photolithography. But the main advantage is that the 3D structure of the mask can be replicated into the polymer. For that purpose, the masks (developped at LMIS1, EPFL) are made of amore » silicon nitride membrane 100 nm thick, on which 3D gold structures up to 200 nm thick, are deposited. The 3D Au structures are made with the nanostencil method, based on successive gold deposition. The IMA institute, from HE-Arc, owns a High Voltage Engineering 1.7 MV Tandetron with both solid and gaseous negative ion sources, able to generate ions from almost every chemical element in a broad range of energies comprised between 400 keV and 6.8 MeV. The beam composition and energy are chosen in such a way, that ions lose a significant fraction of their energy when passing through the thickest regions of the mask. Ions passing through thinner regions of the mask loose a smaller fraction of their energy and etch the polymer with larger thicknesses, allowing a replication of the mask into the polymer. For our trials, we have used a carbon beam with an energy of 500 keV. The beam was focussed to a diameter of 5 mm with solid slits, in order to avoid border effects and thus ensure a homogeneous dose distribution on the beam diameter. The feasibility of this technique has been demonstrated, allowing industrial applications for micro-mould fabrication, micro-fluidics and micro-optics.« less

Method for the manufacture of phase shifting masks for EUV lithography

DOEpatents

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

2006-04-04

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

System and method for high power diode based additive manufacturing

DOEpatents

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

2018-01-02

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

System and method for high power diode based additive manufacturing

DOEpatents

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

2016-04-12

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

Deep reactive ion etching of 4H-SiC via cyclic SF6/O2 segments

NASA Astrophysics Data System (ADS)

Luna, Lunet E.; Tadjer, Marko J.; Anderson, Travis J.; Imhoff, Eugene A.; Hobart, Karl D.; Kub, Fritz J.

2017-10-01

Cycles of inductively coupled SF6/O2 plasma with low (9%) and high (90%) oxygen content etch segments are used to produce up to 46.6 µm-deep trenches with 5.5 µm-wide openings in single-crystalline 4H-SiC substrates. The low oxygen content segment serves to etch deep in SiC whereas the high oxygen content segment serves to etch SiC at a slower rate, targeting carbon-rich residues on the surface as the combination of carbon-rich and fluorinated residues impact sidewall profile. The cycles work in concert to etch past 30 µm at an etch rate of ~0.26 µm min-1 near room temperature, while maintaining close to vertical sidewalls, high aspect ratio, and high mask selectivity. In addition, power ramps during the low oxygen content segment is used to produce a 1:1 ratio of mask opening to trench bottom width. The effect of process parameters such as cycle time and backside substrate cooling on etch depth and micromasking of the electroplated nickel etch mask are investigated.

Fabrication of volcano-shaped nano-patterned sapphire substrates using colloidal self-assembly and wet chemical etching.

PubMed

Geng, Chong; Zheng, Lu; Fang, Huajing; Yan, Qingfeng; Wei, Tongbo; Hao, Zhibiao; Wang, Xiaoqing; Shen, Dezhong

2013-08-23

Patterned sapphire substrates (PSS) have been widely used to enhance the light output power in GaN-based light emitting diodes. The shape and feature size of the pattern in a PSS affect its enhancement efficiency to a great degree. In this work we demonstrate the nanoscale fabrication of volcano-shaped PSS using a wet chemical etching approach in combination with a colloidal monolayer templating strategy. Detailed analysis by scanning electron microscopy reveals that the unique pattern shape is a result of the different corrosion-resistant abilities of silica masks of different effective heights during wet chemical etching. The formation of silica etching masks of different effective heights has been ascribed to the silica precursor solution in the interstice of the colloidal monolayer template being distributed unevenly after infiltration. In the subsequent wet chemical etching process, the active reaction sites altered as etching duration was prolonged, resulting in the formation of volcano-shaped nano-patterned sapphire substrates.

Technological development of spectral filters for Sentinel-2

NASA Astrophysics Data System (ADS)

Schröter, Karin; Schallenberg, Uwe; Mohaupt, Matthias

2017-11-01

In the frame of the initiative for Global Monitoring for Environment and Security (GMES), jointly undertaken by the European Commission and the European Space Agency a technological development of two filter assemblies was performed for the Multi- Spectral Instrument (MSI) for Sentinel-2. The multispectral pushbroom imaging of the Earth will be performed in 10 VNIR bands (from 443 nm to 945nm) and 3 SWIR bands (from 1375 nm to 2190 nm). Possible filter coating techniques and masking concepts were considered in the frame of trade-off studies. The selected deposition concept is based on self-blocked all-dielectric multilayer band pass filter. Band pass and blocking characteristic is deposited on the space side of a single filter substrate whereas the detector side of the substrate has an antireflective coating. The space- and detector side masking design is realized by blades integrated in the mechanical parts including the mechanical interface to the filter assembly support on the MSI focal plane. The feasibility and required performance of the VNIR Filter Assembly and SWIR Filter Assembly were successfully demonstrated by breadboarding. Extensive performance tests of spectral and optical parameters and environmental tests (radiation, vibration, shock, thermal vacuum cycling, humidity) were performed on filter stripe- and filter assembly level. The presentation will contain a detailed description of the filter assembly design and the results of the performance and environmental tests.

A review of nanoimprint lithography for high-volume semiconductor device manufacturing

NASA Astrophysics Data System (ADS)

Resnick, Douglas J.; Choi, Jin

2017-06-01

Imprint lithography has been shown to be a promising technique for the replication of nanoscale features. Jet and flash imprint lithography (J-FIL) [jet and flash imprint lithography and J-FIL are trademarks of Molecular Imprints, Inc.] 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. After this filling step, the resist is cross-linked under UV radiation, and then the mask is removed, leaving a patterned resist on the substrate. There are many criteria that determine whether a particular technology is ready for wafer manufacturing. Included on the list are overlay, throughput, and defectivity. The most demanding devices now require an overlay of better than 4 nm, 3σ. Throughput for an imprint tool is generally targeted at 80 wafers/h. Defectivity and mask life play a significant role relative to meeting the cost of ownership (CoO) requirements in the production of semiconductor devices. The purpose of this paper is to report the status of throughput and defectivity work and to describe the progress made in addressing overlay for advanced devices. To address high-order corrections, a high-order distortion correction (HODC) system is introduced. The combination of applying magnification actuation to the mask and temperature correction to the wafer is described in detail. Examples are presented for the correction of K7, K11, and K17 distortions as well as distortions on actual device wafers.

Cost-effective masks for deep x-ray lithography

NASA Astrophysics Data System (ADS)

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

2003-04-01

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

Biofunctionalization of a “Clickable” Organic Layer Photochemically Grafted on Titanium Substrates

PubMed Central

Li, Yan; Zhao, Meirong; Wang, Jun; Liu, Kai; Cai, Chengzhi

2011-01-01

We have developed a general method combining photochemical grafting and copper-catalyzed click chemistry for biofunctionalization of titanium substrates. The UV-activated grafting of an α,ω-alkenyne onto TiO2/Ti substrates provided a “clickable” thin film platform. The selective attachment of the vinyl end of the molecule to the surface was achieved by masking the alkynyl end with a trimethylgermanyl (TMG) protecting group. Subsequently, various oligo(ethylene glycol) (OEG) derivatives terminated with an azido group were attached to the TMG-alkynyl modified titanium surface via a one-pot deprotection/click reaction. The films were characterized by X-ray photoelectron spectroscopy (XPS), contact angle goniometry, ellipsometry, and atomic force microscopy (AFM). We showed that the titanium surface presenting click-immobilized OEG substantially suppressed the nonspecific attachment of protein and cells as compared to the unmodified titanium substrate. Furthermore, glycine-arginine-glycine-aspartate (GRGD), a cell adhesion peptide, was coimmobilized with OEG on the platform. We demonstrated that the resultant GRGD-presenting thin film on Ti substrates can promote the specific adhesion and spreading of AsPC-1 cells. PMID:21417429

Preliminary results for mask metrology using spatial heterodyne interferometry

NASA Astrophysics Data System (ADS)

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

2003-12-01

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

Quantum Information Science Research and Technical Assessment Project

DTIC Science & Technology

2010-08-01

parameter space. This system incorporates heaters, deposition monitors, temperature sensors , and adjustable substrate holders and masks under high...thickness monitor; G = glass surfaces for transmission measurements; PD = photodiode; TC = thermocouple temperature sensors . Substrate Preparation...crystal due to the mass of material deposited on the crystal. By adjusting the distance of the sensor relative to the source and employing the ~1/R2

Wafer Scale Integration of CMOS Chips for Biomedical Applications via Self-Aligned Masking.

PubMed

Uddin, Ashfaque; Milaninia, Kaveh; Chen, Chin-Hsuan; Theogarajan, Luke

2011-12-01

This paper presents a novel technique for the integration of small CMOS chips into a large area substrate. A key component of the technique is the CMOS chip based self-aligned masking. This allows for the fabrication of sockets in wafers that are at most 5 µm larger than the chip on each side. The chip and the large area substrate are bonded onto a carrier such that the top surfaces of the two components are flush. The unique features of this technique enable the integration of macroscale components, such as leads and microfluidics. Furthermore, the integration process allows for MEMS micromachining after CMOS die-wafer integration. To demonstrate the capabilities of the proposed technology, a low-power integrated potentiostat chip for biosensing implemented in the AMI 0.5 µm CMOS technology is integrated in a silicon substrate. The horizontal gap and the vertical displacement between the chip and the large area substrate measured after the integration were 4 µm and 0.5 µm, respectively. A number of 104 interconnects are patterned with high-precision alignment. Electrical measurements have shown that the functionality of the chip is not affected by the integration process.

Extreme ultraviolet lithography machine

DOEpatents

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

2000-01-01

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

Measuring and Modeling the Growth Dynamics of Self-Catalyzed GaP Nanowire Arrays.

PubMed

Oehler, Fabrice; Cattoni, Andrea; Scaccabarozzi, Andrea; Patriarche, Gilles; Glas, Frank; Harmand, Jean-Christophe

2018-02-14

The bottom-up fabrication of regular nanowire (NW) arrays on a masked substrate is technologically relevant, but the growth dynamic is rather complex due to the superposition of severe shadowing effects that vary with array pitch, NW diameter, NW height, and growth duration. By inserting GaAsP marker layers at a regular time interval during the growth of a self-catalyzed GaP NW array, we are able to retrieve precisely the time evolution of the diameter and height of a single NW. We then propose a simple numerical scheme which fully computes shadowing effects at play in infinite arrays of NWs. By confronting the simulated and experimental results, we infer that re-emission of Ga from the mask is necessary to sustain the NW growth while Ga migration on the mask must be negligible. When compared to random cosine or random uniform re-emission from the mask, the simple case of specular reflection on the mask gives the most accurate account of the Ga balance during the growth.

Drosophila as an unconventional substrate for microfabrication

NASA Astrophysics Data System (ADS)

Shum, Angela J.; Parviz, Babak A.

2007-02-01

We present the application of Drosophila fruit flies as an unconventional substrate for microfabrication. Drosophila by itself represents a complex system capable of many functions not attainable with current microfabrication technology. By using Drosophila as a substrate, we are able to capitalize on these natural functions while incorporating additional functionality into a superior hybrid system. In the following, development of microfabrication processes for Drosophila substrates is discussed. In particular, results of a study on Drosophila tolerance to vacuum pressure during multiple stages of development are given. A remarkable finding that adult Drosophila may withstand up to 3 hours of exposure to vacuum with measurable survival is noted. This finding opens a number of new opportunities for performing fabrication processes, similar to the ones performed on a silicon wafer, on a fruit fly as a live substrate. As a model microfabrication process, it is shown how a collection of Drosophila can be made to self-assemble into an array of microfabricated recesses on a silicon wafer and how a shadow mask can be used to thermally evaporate 100 nm of indium on flies. The procedure resulted in the production of a number of live flies with a pre-designed metal micropattern on their wings. This demonstration of vacuum microfabrication on a live organism provides the first step towards the development of a hybrid biological/solid-state manufacturing process for complex microsystems.

Modification of Surface Energy via Direct Laser Ablative Surface Patterning

NASA Technical Reports Server (NTRS)

Wohl, Christopher J., Jr. (Inventor); Belcher, Marcus A. (Inventor); Connell, John W. (Inventor); Hopkins, John W. (Inventor)

2015-01-01

Surface energy of a substrate is changed without the need for any template, mask, or additional coating medium applied to the substrate. At least one beam of energy directly ablates a substrate surface to form a predefined topographical pattern at the surface. Each beam of energy has a width of approximately 25 micrometers and an energy of approximately 1-500 microJoules. Features in the topographical pattern have a width of approximately 1-500 micrometers and a height of approximately 1.4-100 micrometers.

In HepG2 Cells, Coexisting Carnitine Deficiency Masks Important Indicators of Marginal Biotin Deficiency123

PubMed Central

Bogusiewicz, Anna; Boysen, Gunnar; Mock, Donald M

2015-01-01

Background: A large number of birth defects are related to nutrient deficiencies; concern that biotin deficiency is teratogenic in humans is reasonable. Surprisingly, studies indicate that increased urinary 3-hydroxyisovalerylcarnitine (3HIAc), a previously validated marker of biotin deficiency, is not a valid biomarker in pregnancy. Objective: In this study we hypothesized that coexisting carnitine deficiency can prevent the increase in 3HIAc due to biotin deficiency. Methods: We used a 2-factor nutrient depletion design to induce isolated and combined biotin and carnitine deficiency in HepG2 cells and then repleted cells with carnitine. To elucidate the metabolic pathogenesis, we quantitated intracellular and extracellular free carnitine, acylcarnitines, and acylcarnitine ratios using liquid chromatography–tandem mass spectrometry. Results: Relative to biotin-sufficient, carnitine-sufficient cells, intracellular acetylcarnitine increased by 90%, propionylcarnitine more than doubled, and 3HIAc increased by >10-fold in biotin-deficient, carnitine-sufficient (BDCS) cells, consistent with a defensive mechanism in which biotin-deficient cells transesterify the acyl-coenzyme A (acyl-CoA) substrates of the biotin-dependent carboxylases to the related acylcarnitines. Likewise, in BDCS cells, the ratio of acetylcarnitine to malonylcarnitine and the ratio of propionylcarnitine to methylmalonylcarnitine both more than tripled, and the ratio of 3HIAc to 3-methylglutarylcarnitine (MGc) increased by >10-fold. In biotin-deficient, carnitine-deficient (BDCD) cells, the 3 substrate-derived acylcarnitines changed little, but the substrate:product ratios were masked to a lesser extent. Moreover, carnitine repletion unmasked biotin deficiency in BDCD cells as shown by increases in acetylcarnitine, propionylcarnitine, and 3HIAc (each increased by >50-fold). Likewise, ratios of acetylcarnitine:malonylcarnitine, propionylcarnitine:methylmalonylcarnitine, and 3HIAc:MGc all increased by >8-fold. Conclusions: Our findings provide strong evidence that coexisting carnitine deficiency masks some indicators of biotin deficiency and support the potential importance of the ratios of acylcarnitines arising from the acyl-CoA substrates and products for biotin-dependent carboxylases in detecting the biotin deficiency that is masked by coexisting carnitine deficiency. PMID:25527659

In HepG2 cells, coexisting carnitine deficiency masks important indicators of marginal biotin deficiency.

PubMed

Bogusiewicz, Anna; Boysen, Gunnar; Mock, Donald M

2015-01-01

A large number of birth defects are related to nutrient deficiencies; concern that biotin deficiency is teratogenic in humans is reasonable. Surprisingly, studies indicate that increased urinary 3-hydroxyisovalerylcarnitine (3HIAc), a previously validated marker of biotin deficiency, is not a valid biomarker in pregnancy. In this study we hypothesized that coexisting carnitine deficiency can prevent the increase in 3HIAc due to biotin deficiency. We used a 2-factor nutrient depletion design to induce isolated and combined biotin and carnitine deficiency in HepG2 cells and then repleted cells with carnitine. To elucidate the metabolic pathogenesis, we quantitated intracellular and extracellular free carnitine, acylcarnitines, and acylcarnitine ratios using liquid chromatography-tandem mass spectrometry. Relative to biotin-sufficient, carnitine-sufficient cells, intracellular acetylcarnitine increased by 90%, propionylcarnitine more than doubled, and 3HIAc increased by >10-fold in biotin-deficient, carnitine-sufficient (BDCS) cells, consistent with a defensive mechanism in which biotin-deficient cells transesterify the acyl-coenzyme A (acyl-CoA) substrates of the biotin-dependent carboxylases to the related acylcarnitines. Likewise, in BDCS cells, the ratio of acetylcarnitine to malonylcarnitine and the ratio of propionylcarnitine to methylmalonylcarnitine both more than tripled, and the ratio of 3HIAc to 3-methylglutarylcarnitine (MGc) increased by >10-fold. In biotin-deficient, carnitine-deficient (BDCD) cells, the 3 substrate-derived acylcarnitines changed little, but the substrate:product ratios were masked to a lesser extent. Moreover, carnitine repletion unmasked biotin deficiency in BDCD cells as shown by increases in acetylcarnitine, propionylcarnitine, and 3HIAc (each increased by >50-fold). Likewise, ratios of acetylcarnitine:malonylcarnitine, propionylcarnitine:methylmalonylcarnitine, and 3HIAc:MGc all increased by >8-fold. Our findings provide strong evidence that coexisting carnitine deficiency masks some indicators of biotin deficiency and support the potential importance of the ratios of acylcarnitines arising from the acyl-CoA substrates and products for biotin-dependent carboxylases in detecting the biotin deficiency that is masked by coexisting carnitine deficiency. © 2015 American Society for Nutrition.

Grafted Polystyrene Monolayer Brush as Both Negative and Positive Tone Electron Beam Resist.

PubMed

Aydinoglu, Ferhat; Yamada, Hirotaka; Dey, Ripon K; Cui, Bo

2017-05-23

Although spin coating is the most widely used electron-beam resist coating technique in nanolithography, it cannot typically be applied for nonflat or irregular surfaces. Here, we demonstrate that monolayer polystyrene brush can be grafted on substrates and used as both positive and negative electron-beam resist, which can be applied for such unconventional surfaces. Polystyrene is a popular negative resist when using solvent developer but solvent cannot be used for grafted polystyrene brush that is firmly bonded to the substrate. Instead, we employed two unconventional development methods to lead polystyrene brush to positive or negative tone behavior. Negative tone was achieved by thermal development at 300 °C because exposed thus cross-linked polystyrene brush is more thermally stable against vaporization than unexposed linear one. Surprisingly, positive tone behavior occurred when the brush was grafted onto an aluminum (Al) layer and the film stack was developed using diluted hydrofluoric acid (HF) that etched the underlying Al layer. By transferring the patterns into the silicon (Si) substrates using the thin Al layer as a sacrificial hard mask for dry etch, well-defined structures in Si were obtained in two different electron-beam resist tones as well as in nonflat surfaces.

Method for deposition of a conductor in integrated circuits

DOEpatents

Creighton, J. Randall; Dominguez, Frank; Johnson, A. Wayne; Omstead, Thomas R.

1997-01-01

A method is described for fabricating integrated semiconductor circuits and, more particularly, for the selective deposition of a conductor onto a substrate employing a chemical vapor deposition process. By way of example, tungsten can be selectively deposited onto a silicon substrate. At the onset of loss of selectivity of deposition of tungsten onto the silicon substrate, the deposition process is interrupted and unwanted tungsten which has deposited on a mask layer with the silicon substrate can be removed employing a halogen etchant. Thereafter, a plurality of deposition/etch back cycles can be carried out to achieve a predetermined thickness of tungsten.

Silica substrate or portion formed from oxidation of monocrystalline silicon

DOEpatents

Matzke, Carolyn M.; Rieger, Dennis J.; Ellis, Robert V.

2003-07-15

A method is disclosed for forming an inclusion-free silica substrate using a monocrystalline silicon substrate as the starting material and oxidizing the silicon substrate to convert it entirely to silica. The oxidation process is performed from both major surfaces of the silicon substrate using a conventional high-pressure oxidation system. The resulting product is an amorphous silica substrate which is expected to have superior etching characteristics for microfabrication than conventional fused silica substrates. The present invention can also be used to convert only a portion of a monocrystalline silicon substrate to silica by masking the silicon substrate and locally thinning a portion the silicon substrate prior to converting the silicon portion entirely to silica. In this case, the silica formed by oxidizing the thinned portion of the silicon substrate can be used, for example, as a window to provide optical access through the silicon substrate.

Directed Self-Assembly of Epitaxial CoFe2O4-BiFeO3 Multiferroic Nanocomposites

DTIC Science & Technology

2012-04-09

has been limited. One method to produce patterned magneto- electric composites is to use a porous anodic aluminum oxide ( AAO ) film as a liftoff mask...control found in the BFO−CFO 1-3 epitaxial nanocomposites.6,8 Additionally, the AAO and membrane masks are not practical for the formation of a square...during deposition, which produces a hexagonal array pattern.12,13 In one approach, a BTO−CFO multilayer is deposited onto the AAO film on a STO substrate

Defect reduction for semiconductor memory applications using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Ye, Zhengmao; Luo, Kang; Lu, Xiaoming; Fletcher, Brian; Liu, Weijun; Xu, Frank; LaBrake, Dwayne; Resnick, Douglas J.; Sreenivasan, S. V.

2012-07-01

Acceptance of imprint lithography for manufacturing will require demonstration that it can attain defect levels commensurate with the defect specifications of high-end memory devices. Defects occurring during imprinting can generally be broken into two categories; random defects and repeating defects. Examples of random defects include fluid phase imprint defects, such as bubbles, and solid phase imprint defects, such as line collapse. Examples of repeater defects include mask fabrication defects and particle induced defects. Previous studies indicated that soft particles cause nonrepeating defects. Hard particles, on the other hand, can cause either permanent resist plugging or mask damage. In a previous study, two specific defect types were examined; random nonfill defects occurring during the resist filling process and repeater defects caused by interactions with particles on the substrate. We attempted to identify the different types of imprint defect types using a mask with line/space patterns at dimensions as small as 26 nm. An Imprio 500 twenty-wafer per hour development tool was used to study the various defect types. The imprint defect density was reduced nearly four orders of magnitude, down to ˜4/cm2 in a period of two years following the availability of low defect imprint masks at 26-nm half-pitch. This reduction was achieved by identifying the root cause of various defects and then taking the appropriate corrective action.

A Comprehensive Surface Mount Technology Solution for Integrated Circuits onto Flexible Screen Printed Electrical Interconnects

DTIC Science & Technology

2014-05-19

their acceptable thermal stability, Polyimides have established as a conventional substrate material for flexible interconnects, which can be...of the silver flake ink for the screen-printed interconnects, the assembled unit fulfills biocompatibility requirements in a limited manner ([29...30]). Even though biocompatibility of substrate [31] is fulfilled, toxicity of the insulating mask [32] and encapsulation need to be considered

Fabrication of wedged multilayer Laue lenses

DOE PAGES

Prasciolu, M.; Leontowich, A. F. G.; Krzywinski, J.; ...

2015-01-01

We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Bragg’s law for all layers in the stack.more » This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.« less

Strong geometrical effects in submillimeter selective area growth and light extraction of GaN light emitting diodes on sapphire

DOE PAGES

Tanaka, Atsunori; Chen, Renjie; Jungjohann, Katherine L.; ...

2015-11-27

Advanced semiconductor devices often utilize structural and geometrical effects to tailor their characteristics and improve their performance. Our detailed understanding of such geometrical effects in the epitaxial selective area growth of GaN on sapphire substrates is reported here, and we utilize them to enhance light extraction from GaN light emitting diodes. Systematic size and spacing effects were performed side-by-side on a single 2” sapphire substrate to minimize experimental sampling errors for a set of 144 pattern arrays with circular mask opening windows in SiO 2. We show that the mask opening diameter leads to as much as 4 times increasemore » in the thickness of the grown layers for 20 μm spacings and that spacing effects can lead to as much as 3 times increase in thickness for a 350 μm dot diameter. We also observed that the facet evolution in comparison with extracted Ga adatom diffusion lengths directly influences the vertical and lateral overgrowth rates and can be controlled with pattern geometry. Lastly, such control over the facet development led to 2.5 times stronger electroluminescence characteristics from well-faceted GaN/InGaN multiple quantum well LEDs compared to non-faceted structures.« less

Effectiveness of Combination of Dentin and Enamel Layers on the Masking Ability of Porcelain.

PubMed

Boscato, Noéli; Hauschild, Fernando Gabriel; Kaizer, Marina da Rosa; De Moraes, Rafael Ratto

2015-01-01

This study evaluated the masking ability of different porcelain thicknesses and combination of enamel and/or dentin porcelain layers over simulated background dental substrates with higher (A2) and lower (C4) color values. Combination of the enamel (E) and dentin (D) monolayer porcelain disks with different thicknesses (0.5 mm, 0.8 mm, and 1 mm) resulted in the following bilayer groups (n=10): D1E1, D1E0.8; D1E0.5; D0.8E0.8; D0.8E0.5, and D0.5E0.5. CIELAB color coordinates were measured with a spectrophotometer. The translucency parameter of mono and bilayer specimens and the masking ability estimated by color variation (ΔE*ab) of bilayer specimens over simulated dental substrates were evaluated. Linear regression analysis was used to investigate the relationships translucency parameter × ΔE*, translucency parameter × porcelain thickness, and ΔE* × porcelain thickness. Data were analyzed statistically (α= 0.05). Thinner porcelain disks were associated with higher translucency. Porcelain monolayers were considerably more translucent than bilayers (enamel + dentin). Dentin porcelain was less translucent than enamel porcelain with same thickness. ΔE* was always lower when measured over A2 background. Higher ΔE* was observed for the C4 background, indicating poorer masking ability. Increased ΔE* was significantly associated with increased translucency for both backgrounds. Decreased translucency and ΔE* were associated with increased total porcelain thickness or increased dentin thickness for both backgrounds. In conclusion, increased porcelain thickness (particularly increased dentin layer) and increased porcelain opacity resulted in better masking ability of the dental backgrounds.

Stress engineering in GaN structures grown on Si(111) substrates by SiN masking layer application

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

Szymański, Tomasz, E-mail: tomasz.szymanski@pwr.edu.pl; Wośko, Mateusz; Paszkiewicz, Bogdan

2015-07-15

GaN layers without and with an in-situ SiN mask were grown by using metal organic vapor phase epitaxy for three different approaches used in GaN on silicon(111) growth, and the physical and optical properties of the GaN layers were studied. For each approach applied, GaN layers of 1.4 μm total thickness were grown, using silan SiH{sub 4} as Si source in order to grow Si{sub x}N{sub x} masking layer. The optical micrographs, scanning electron microscope images, and atomic force microscope images of the grown samples revealed cracks for samples without SiN mask, and micropits, which were characteristic for the samples grownmore » with SiN mask. In situ reflectance signal traces were studied showing a decrease of layer coalescence time and higher degree of 3D growth mode for samples with SiN masking layer. Stress measurements were conducted by two methods—by recording micro-Raman spectra and ex-situ curvature radius measurement—additionally PLs spectra were obtained revealing blueshift of PL peak positions with increasing stress. The authors have shown that a SiN mask significantly improves physical and optical properties of GaN multilayer systems reducing stress in comparison to samples grown applying the same approaches but without SiN masking layer.« less

Mechanically adjustable single-molecule transistors and stencil mask nanofabrication of high-resolution scanning probes

NASA Astrophysics Data System (ADS)

Champagne, Alexandre

This dissertation presents the development of two original experimental techniques to probe nanoscale objects. The first one studies electronic transport in single organic molecule transistors in which the source-drain electrode spacing is mechanically adjustable. The second involves the fabrication of high-resolution scanning probe microscopy sensors using a stencil mask lithography technique. We describe the fabrication of transistors in which a single organic molecule can be incorporated. The source and drain leads of these transistors are freely suspended above a flexible substrate, and their spacing can be adjusted by bending the substrate. We detail the technology developed to carry out measurements on these samples. We study electronic transport in single C60 molecules at low temperature. We observe Coulomb blockaded transport and can resolve the discrete energy spectrum of the molecule. We are able to mechanically tune the spacing between the electrodes (over a range of 5 A) to modulate the lead-molecule coupling, and can electrostatically tune the energy levels on the molecule by up to 160 meV using a gate electrode. Initial progress in studying different transport regimes in other molecules is also discussed. We present a lithographic process that allows the deposition of metal nanostructures with a resolution down to 10 nm directly onto atomic force microscope (AFM) tips. We show that multiple layers of lithography can be deposited and aligned. We fabricate high-resolution magnetic force microscopy (MFM) probes using this method and discuss progress to fabricate other scanning probe microscopy (SPM) sensors.

Stress engineering of high-quality single crystal diamond by heteroepitaxial lateral overgrowth

DOE PAGES

Tang, Y. -H.; Golding, B.

2016-02-02

Here, we describe a method for lateral overgrowth of low-stress single crystal diamond by chemical vapor deposition (CVD). The process is initiated by deposition of a thin (550 nm) (001) diamond layer on Ir-buffered a-plane sapphire. The diamond is partially masked by periodic thermally evaporated Au stripes using photolithography. Lateral overgrowth of the Au occurs with extremely effective filtering of threading dislocations. Thermal stress resulting from mismatch of the low thermal expansion diamond and the sapphire substrate is largely accommodated by the ductile Au layer. The stress state of the diamond is investigated by Raman spectroscopy for two thicknesses: atmore » 10 μm where the film has just overgrown the Au mask and at 180 μm where the film thickness greatly exceeds the scale of the masking. For the 10-μm film, the Raman linewidth shows spatial oscillations with the period of the Au stripes with a factor of 2 to 3 reduction relative to the unmasked region. In a 180-μm thick diamond film, the overall surface stress was extremely low, 0.00 ± 0.16 GPa, obtained from the Raman shift averaged over the 7.5mm diameter of the crystal at its surface. We conclude that the metal mask protects the overgrown diamond layer from substrate-induced thermal stress and cracking. Lastly, it is also responsible for low internal stress by reducing dislocation density by several orders of magnitude.« less

Modeling Visible/Near-Infrared Photometric Properties of Dustfall on a Known Substrate

NASA Technical Reports Server (NTRS)

Sohl-Dickstein, J.; Johnson, J. R.; Grundy, W. M.; Guinness, E.; Graff, T.; Shepard, M. K.; Arvidson, R. E.; Bell, J. F., III; Christensen, P.; Morris, R.

2005-01-01

We present a comprehensive visible/near-infrared two-layer radiative transfer modeling study using laboratory spectra of variable dust thicknesses deposited on substrates with known photometric parameters. The masking effects of Martian airfall dust deposition on rocks, soils, and lander/rover components provides the incentive to improve two-layer models [1-3]. It is believed that the model presented will facilitate understanding of the spectral and compositional properties of both the dust layer and substrate material, and allow for better compensation for dust deposition.

Enhancing the efficiency of sortase-mediated ligations through nickel-peptide complex formation.

PubMed

David Row, R; Roark, Travis J; Philip, Marina C; Perkins, Lorena L; Antos, John M

2015-08-14

A modified sortase A recognition motif containing a masked Ni(2+)-binding peptide was employed to boost the efficiency of sortase-catalyzed ligation reactions. Deactivation of the Ni(2+)-binding peptide using a Ni(2+) additive improved reaction performance at low to equimolar ratios of the glycine amine nucleophile and sortase substrate. The success of this approach was demonstrated with both peptide and protein substrates.

Maskless, reticle-free, lithography

DOEpatents

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

1997-11-25

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

Maskless, reticle-free, lithography

DOEpatents

Ceglio, Natale M.; Markle, David A.

1997-11-25

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

Copper circuit patterning on polymer using selective surface modification and electroless plating

NASA Astrophysics Data System (ADS)

Park, Sang Jin; Ko, Tae-Jun; Yoon, Juil; Moon, Myoung-Woon; Oh, Kyu Hwan; Han, Jun Hyun

2017-02-01

We have examined a potential new and simple method for patterning a copper circuit on PET substrate by copper electroless plating, without the pretreatment steps (i.e., sensitization and activation) for electroless plating as well as the etching processes of conventional circuit patterning. A patterned mask coated with a catalyst material, Ag, for the reduction of Cu ions, is placed on a PET substrate. Subsequent oxygen plasma treatment of the PET substrate covered with the mask promotes the selective generation of anisotropic pillar- or hair-like nanostructures coated with co-deposited nanoparticles of the catalyst material on PET. After oxygen plasma treatment, a Cu circuit is well formed just by dipping the plasma-treated PET into a Cu electroless plating solution. By increasing the oxygen gas pressure in the chamber, the height of the nanostructures increases and the Ag catalyst particles are coated on not only the top but also the side surfaces of the nanostructures. Strong mechanical interlocking between the Cu circuit and PET substrate is produced by the large surface area of the nanostructures, and enhances peel strength. Results indicate this new simple two step (plasma surface modification and pretreatment-free electroless plating) method can be used to produce a flexible Cu circuit with good adhesion.

Diffractive phase-shift lithography photomask operating in proximity printing mode.

PubMed

Cirino, Giuseppe A; Mansano, Ronaldo D; Verdonck, Patrick; Cescato, Lucila; Neto, Luiz G

2010-08-02

A phase shift proximity printing lithographic mask is designed, manufactured and tested. Its design is based on a Fresnel computer-generated hologram, employing the scalar diffraction theory. The obtained amplitude and phase distributions were mapped into discrete levels. In addition, a coding scheme using sub-cells structure was employed in order to increase the number of discrete levels, thus increasing the degree of freedom in the resulting mask. The mask is fabricated on a fused silica substrate and an amorphous hydrogenated carbon (a:C-H) thin film which act as amplitude modulation agent. The lithographic image is projected onto a resist coated silicon wafer, placed at a distance of 50 microm behind the mask. The results show a improvement of the achieved resolution--linewidth as good as 1.5 microm--what is impossible to obtain with traditional binary masks in proximity printing mode. Such achieved dimensions can be used in the fabrication of MEMS and MOEMS devices. These results are obtained with a UV laser but also with a small arc lamp light source exploring the partial coherence of this source.

Method for deposition of a conductor in integrated circuits

DOEpatents

Creighton, J.R.; Dominguez, F.; Johnson, A.W.; Omstead, T.R.

1997-09-02

A method is described for fabricating integrated semiconductor circuits and, more particularly, for the selective deposition of a conductor onto a substrate employing a chemical vapor deposition process. By way of example, tungsten can be selectively deposited onto a silicon substrate. At the onset of loss of selectivity of deposition of tungsten onto the silicon substrate, the deposition process is interrupted and unwanted tungsten which has deposited on a mask layer with the silicon substrate can be removed employing a halogen etchant. Thereafter, a plurality of deposition/etch back cycles can be carried out to achieve a predetermined thickness of tungsten. 2 figs.

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

NASA Astrophysics Data System (ADS)

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

2011-11-01

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

Method of making low leakage N-channel SOS transistors utilizing positive photoresist masking techniques

NASA Technical Reports Server (NTRS)

Policastro, Steven G. (Inventor); Woo, Dae-Shik (Inventor)

1983-01-01

A self-aligned method of implanting the edges of NMOS/SOS transistors is described. The method entails covering the silicon islands with a thick oxide layer, applying a protective photoresist layer over the thick oxide layer, and exposing the photoresist layer from the underside of the sapphire substrate thereby using the island as an exposure mask. Only the photoresist on the islands' edges will be exposed. The exposed photoresist is then removed and the thick oxide is removed from the islands edges which are then implanted.

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

PubMed

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

2018-04-04

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

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

NASA Astrophysics Data System (ADS)

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

2016-03-01

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

Integrated Optical Information Processing

DTIC Science & Technology

1988-08-01

applications in optical disk memory systems [91. This device is constructed in a glass /SiO2/Si waveguide. The choice of a Si substrate allows for the...contact mask) were formed in the photoresist deposited on all of the samples, we covered the unwanted gratings on each sample with cover glass slides...processing, let us consider TeO2 (v, = 620 m/s) as a potential substrate for applications requiring large time delays. This con- sideration is despite

The JWST/NIRCam Coronagraph: Mask Design and Fabrication

NASA Technical Reports Server (NTRS)

Krista, John E.; Balasubramanian, Kunjithapatha; Beichman, Charles A.; Echternach, Pierre M.; Green, Joseph J.; Liewer, Kurt M.; Muller, Richard E.; Serabyn, Eugene; Shaklan, Stuart B.; Trauger, John T.;

Nanofabrication on monocrystalline silicon through friction-induced selective etching of Si3N4 mask

PubMed Central

2014-01-01

A new fabrication method is proposed to produce nanostructures on monocrystalline silicon based on the friction-induced selective etching of its Si3N4 mask. With low-pressure chemical vapor deposition (LPCVD) Si3N4 film as etching mask on Si(100) surface, the fabrication can be realized by nanoscratching on the Si3N4 mask and post-etching in hydrofluoric acid (HF) and potassium hydroxide (KOH) solution in sequence. Scanning Auger nanoprobe analysis indicated that the HF solution could selectively etch the scratched Si3N4 mask and then provide the gap for post-etching of silicon substrate in KOH solution. Experimental results suggested that the fabrication depth increased with the increase of the scratching load or KOH etching period. Because of the excellent masking ability of the Si3N4 film, the maximum fabrication depth of nanostructure on silicon can reach several microns. Compared to the traditional friction-induced selective etching technique, the present method can fabricate structures with lesser damage and deeper depths. Since the proposed method has been demonstrated to be a less destructive and flexible way to fabricate a large-area texture structure, it will provide new opportunities for Si-based nanofabrication. PMID:24940174

Heat pipe with improved wick structures

DOEpatents

Benson, David A.; Robino, Charles V.; Palmer, David W.; Kravitz, Stanley H.

2000-01-01

An improved planar heat pipe wick structure having projections formed by micromachining processes. The projections form arrays of interlocking, semi-closed structures with multiple flow paths on the substrate. The projections also include overhanging caps at their tops to increase the capillary pumping action of the wick structure. The capped projections can be formed in stacked layers. Another layer of smaller, more closely spaced projections without caps can also be formed on the substrate in between the capped projections. Inexpensive materials such as Kovar can be used as substrates, and the projections can be formed by electrodepositing nickel through photoresist masks.

High Precision Metal Thin Film Liftoff Technique

NASA Technical Reports Server (NTRS)

Brown, Ari D. (Inventor); Patel, Amil A. (Inventor)

2015-01-01

A metal film liftoff process includes applying a polymer layer onto a silicon substrate, applying a germanium layer over the polymer layer to create a bilayer lift off mask, applying a patterned photoresist layer over the germanium layer, removing an exposed portion of the germanium layer, removing the photoresist layer and a portion of the polymer layer to expose a portion of the substrate and create an overhanging structure of the germanium layer, depositing a metal film over the exposed portion of the substrate and the germanium layer, and removing the polymer and germanium layers along with the overlaying metal film.

Robotic Patterning a Superhydrophobic Surface for Collective Cell Migration Screening.

PubMed

Pang, Yonggang; Yang, Jing; Hui, Zhixin; Grottkau, Brian E

2018-04-01

Collective cell migration, in which cells migrate as a group, is fundamental in many biological and pathological processes. There is increasing interest in studying the collective cell migration in high throughput. Cell scratching, insertion blocker, and gel-dissolving techniques are some methodologies used previously. However, these methods have the drawbacks of cell damage, substrate surface alteration, limitation in medium exchange, and solvent interference. The superhydrophobic surface, on which the water contact angle is greater than 150 degrees, has been recently utilized to generate patterned arrays. Independent cell culture areas can be generated on a substrate that functions the same as a conventional multiple well plate. However, so far there has been no report on superhydrophobic patterning for the study of cell migration. In this study, we report on the successful development of a robotically patterned superhydrophobic array for studying collective cell migration in high throughput. The array was developed on a rectangular single-well cell culture plate consisting of hydrophilic flat microwells separated by the superhydrophobic surface. The manufacturing process is robotic and includes patterning discrete protective masks to the substrate using 3D printing, robotic spray coating of silica nanoparticles, robotic mask removal, robotic mini silicone blocker patterning, automatic cell seeding, and liquid handling. Compared with a standard 96-well plate, our system increases the throughput by 2.25-fold and generates a cell-free area in each well non-destructively. Our system also demonstrates higher efficiency than conventional way of liquid handling using microwell plates, and shorter processing time than manual operating in migration assays. The superhydrophobic surface had no negative impact on cell viability. Using our system, we studied the collective migration of human umbilical vein endothelial cells and cancer cells using assays of endpoint quantification, dynamic cell tracking, and migration quantification following varied drug treatments. This system provides a versatile platform to study collective cell migration in high throughput for a broad range of applications.

Synthesis and patterning of polymers for biomedical applications

NASA Astrophysics Data System (ADS)

He, Wei

The goal of this dissertation is to synthesize and characterize novel polymers, as well as to explore alternative techniques for biomedical applications. Although significant progress has been achieved in the design and preparation of new biomaterials over the past years, much remains to be accomplished. The interactions between biomaterials and cells are very important, especially in the emerging field of tissue engineering. The focus of this research is to improve such interactions via several different approaches. One way to engineer cellular interaction is by modifying surface topography through micro-patterning. Although photolithography is widely used for patterning, it is not suitable for direct cell and protein patterning because of the usage of organic solvent for feature development. To address this issue, a biocompatible chemically amplified resist derived from N-vinyl-2-pyrrolidone (NVP) was prepared. The results have shown that no organic solvent development was required to reveal the patterns and cells can be cultured on these patterned surfaces directly. Strong cell alignment was observed. The other issue addressed in this research is to develop a technique that can modify surface morphology and surface chemistry simultaneously. Such a technique is called masked ion beam lithography (MIBL). By implanting phosphorous ions on polymeric substrates through masks, not only micron/nano size patterns were generated on the surface, but also the phosphorous ions were incorporated. Incubation of bone forming osteoblast cells on these ion beam processed samples has shown that osteoblast cell attachment to the substrate was enhanced, as a consequence of the increased surface roughness as well as the implanted phosphorous ions. This indicates that MIBL can not only generate micro/nanostructures on the surface of a biocompatible polymer, but can also selectively modify the surface chemistry by implanting with specific ions. These factors can contribute to an osteogenic environment.

Self-Assembled Polystyrene Beads for Templated Covalent Functionalization of Graphitic Substrates Using Diazonium Chemistry.

PubMed

Van Gorp, Hans; Walke, Peter; Bragança, Ana M; Greenwood, John; Ivasenko, Oleksandr; Hirsch, Brandon E; De Feyter, Steven

2018-04-11

A network of self-assembled polystyrene beads was employed as a lithographic mask during covalent functionalization reactions on graphitic surfaces to create nanocorrals for confined molecular self-assembly studies. The beads were initially assembled into hexagonal arrays at the air-liquid interface and then transferred to the substrate surface. Subsequent electrochemical grafting reactions involving aryl diazonium molecules created covalently bound molecular units that were localized in the void space between the nanospheres. Removal of the bead template exposed hexagonally arranged circular nanocorrals separated by regions of chemisorbed molecules. Small molecule self-assembly was then investigated inside the resultant nanocorrals using scanning tunneling microscopy to highlight localized confinement effects. Overall, this work illustrates the utility of self-assembly principles to transcend length scale gaps in the development of hierarchically patterned molecular materials.

Atom Chips on Direct Bonded Copper Substrates (Postprint)

DTIC Science & Technology

2012-01-19

joining of a thin sheet of pure copper to a ceramic substrate14 and is commonly used in power electronics due to its high current handling and heat...Squires et al. Rev. Sci. Instrum. 82, 023101 (2011) FIG. 1. A scanning electron micrograph of the top view of test chip A. the photolithographically...the etching pro- cesses and masking methods were quantified using a scanning electron microscope. Two test chips (A and B) are presented below and are

Catalyst patterning for nanowire devices

NASA Technical Reports Server (NTRS)

Li, Jun (Inventor); Cassell, Alan M. (Inventor); Han, Jie (Inventor)

2004-01-01

Nanowire devices may be provided that are based on carbon nanotubes or single-crystal semiconductor nanowires. The nanowire devices may be formed on a substrate. Catalyst sites may be formed on the substrate. The catalyst sites may be formed using lithography, thin metal layers that form individual catalyst sites when heated, collapsible porous catalyst-filled microscopic spheres, microscopic spheres that serve as masks for catalyst deposition, electrochemical deposition techniques, and catalyst inks. Nanowires may be grown from the catalyst sites.

Wafer-Scale Hierarchical Nanopillar Arrays Based on Au Masks and Reactive Ion Etching for Effective 3D SERS Substrate.

PubMed

Men, Dandan; Wu, Yingyi; Wang, Chu; Xiang, Junhuai; Yang, Ganlan; Wan, Changjun; Zhang, Honghua

2018-02-04

Two-dimensional (2D) periodic micro/nanostructured arrays as SERS substrates have attracted intense attention due to their excellent uniformity and good stability. In this work, periodic hierarchical SiO₂ nanopillar arrays decorated with Ag nanoparticles (NPs) with clean surface were prepared on a wafer-scale using monolayer Au NP arrays as masks, followed by reactive ion etching (RIE), depositing Ag layer and annealing. For the prepared SiO₂ nanopillar arrays decorated with Ag NPs, the size of Ag NPs was tuned from ca. 24 to 126 nanometers by controlling the deposition thickness of Ag film. Importantly, the SiO₂ nanopillar arrays decorated with Ag NPs could be used as highly sensitive SERS substrate for the detection of 4-aminothiophenol (4-ATP) and rhodamine 6G (R6G) due to the high loading of Ag NPs and a very uniform morphology. With a deposition thickness of Ag layer of 30 nm, the SiO₂ nanopillar arrays decorated with Ag NPs exhibited the best sensitive SERS activity. The excellent SERS performance of this substrate is mainly attributed to high-density "hotspots" derived from nanogaps between Ag NPs. Furthermore, this strategy might be extended to synthesize other nanostructured arrays with a large area, which are difficult to be prepared only via conventional wet-chemical or physical methods.

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

NASA Astrophysics Data System (ADS)

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

2008-10-01

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

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

NASA Astrophysics Data System (ADS)

Makimura, Tetsuya; Urai, Hikari; Niino, Hiroyuki

2017-03-01

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

Low thermal distortion extreme-UV lithography reticle

DOEpatents

Gianoulakis, Steven E.; Ray-Chaudhuri, Avijit K.

2002-01-01

Thermal distortion of reticles or masks can be significantly reduced by emissivity engineering, i.e., the selective placement or omission of coatings on the reticle. Reflective reticles so fabricated exhibit enhanced heat transfer thereby reducing the level of thermal distortion and ultimately improving the quality of the transcription of the reticle pattern onto the wafer. Reflective reticles include a substrate having an active region that defines the mask pattern and non-active region(s) that are characterized by a surface that has a higher emissivity than that of the active region. The non-active regions are not coated with the radiation reflective material.

Low thermal distortion extreme-UV lithography reticle

DOEpatents

Gianoulakis, Steven E.; Ray-Chaudhuri, Avijit K.

2001-01-01

Thermal distortion of reticles or masks can be significantly reduced by emissivity engineering, i.e., the selective placement or omission of coatings on the reticle. Reflective reticles so fabricated exhibit enhanced heat transfer thereby reducing the level of thermal distortion and ultimately improving the quality of the transcription of the reticle pattern onto the wafer. Reflective reticles include a substrate having an active region that defines the mask pattern and non-active region(s) that are characterized by a surface that has a higher emissivity than that of the active region. The non-active regions are not coated with the radiation reflective material.

Photovoltaic cell and production thereof

DOEpatents

Narayanan, Srinivasamohan [Gaithersburg, MD; Kumar, Bikash [Bangalore, IN

2008-07-22

An efficient photovoltaic cell, and its process of manufacture, is disclosed wherein the back surface p-n junction is removed from a doped substrate having an oppositely doped emitter layer. A front surface and edges and optionally the back surface periphery are masked and a back surface etch is performed. The mask is not removed and acts as an anti-reflective coating, a passivating agent, or both. The photovoltaic cell retains an untextured back surface whether or not the front is textured and the dopant layer on the back surface is removed to enhance the cell efficiency. Optionally, a back surface field is formed.

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

NASA Astrophysics Data System (ADS)

Prakash, Shashi; Kumar, Subrata

2017-09-01

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

Effect of the Fabrication Parameters of the Nanosphere Lithography Method on the Properties of the Deposited Au-Ag Nanoparticle Arrays

PubMed Central

Liu, Jing; Chen, Chaoyang; Yang, Guangsong; Chen, Yushan; Yang, Cheng-Fu

2017-01-01

The nanosphere lithography (NSL) method can be developed to deposit the Au-Ag triangle hexagonal nanoparticle arrays for the generation of localized surface plasmon resonance. Previously, we have found that the parameters used to form the NSL masks and the physical methods required to deposit the Au-Ag thin films had large effects on the geometry properties of the nanoparticle arrays. Considering this, the different parameters used to grow the Au-Ag triangle hexagonal nanoparticle arrays were investigated. A single-layer NSL mask was formed by using self-assembly nano-scale polystyrene (PS) nanospheres with an average radius of 265 nm. At first, the concentration of the nano-scale PS nanospheres in the solution was set at 6 wt %. Two coating methods, drop-coating and spin-coating, were used to coat the nano-scale PS nanospheres as a single-layer NSL mask. From the observations of scanning electronic microscopy (SEM), we found that the matrixes of the PS nanosphere masks fabricated by using the drop-coating method were more uniform and exhibited a smaller gap than those fabricated by the spin-coating method. Next, the drop-coating method was used to form the single-layer NSL mask and the concentration of nano-scale PS nanospheres in a solution that was changed from 4 to 10 wt %, for further study. The SEM images showed that when the concentrations of PS nanospheres in the solution were 6 and 8 wt %, the matrixes of the PS nanosphere masks were more uniform than those of 4 and 10 wt %. The effects of the one-side lifting angle of substrates and the vaporization temperature for the solvent of one-layer self-assembly PS nanosphere thin films, were also investigated. Finally, the concentration of the nano-scale PS nanospheres in the solution was set at 8 wt % to form the PS nanosphere masks by the drop-coating method. Three different physical deposition methods, including thermal evaporation, radio-frequency magnetron sputtering, and e-gun deposition, were used to deposit the Au-Ag triangle hexagonal periodic nanoparticle arrays. The SEM images showed that as the single-layer PS nanosphere mask was well controlled, the thermal evaporation could deposit the Au-Ag triangle hexagonal nanoparticle arrays with a higher quality than the other two methods. PMID:28772741

Effect of the Fabrication Parameters of the Nanosphere Lithography Method on the Properties of the Deposited Au-Ag Nanoparticle Arrays.

PubMed

Liu, Jing; Chen, Chaoyang; Yang, Guangsong; Chen, Yushan; Yang, Cheng-Fu

2017-04-03

The nanosphere lithography (NSL) method can be developed to deposit the Au-Ag triangle hexagonal nanoparticle arrays for the generation of localized surface plasmon resonance. Previously, we have found that the parameters used to form the NSL masks and the physical methods required to deposit the Au-Ag thin films had large effects on the geometry properties of the nanoparticle arrays. Considering this, the different parameters used to grow the Au-Ag triangle hexagonal nanoparticle arrays were investigated. A single-layer NSL mask was formed by using self-assembly nano-scale polystyrene (PS) nanospheres with an average radius of 265 nm. At first, the concentration of the nano-scale PS nanospheres in the solution was set at 6 wt %. Two coating methods, drop-coating and spin-coating, were used to coat the nano-scale PS nanospheres as a single-layer NSL mask. From the observations of scanning electronic microscopy (SEM), we found that the matrixes of the PS nanosphere masks fabricated by using the drop-coating method were more uniform and exhibited a smaller gap than those fabricated by the spin-coating method. Next, the drop-coating method was used to form the single-layer NSL mask and the concentration of nano-scale PS nanospheres in a solution that was changed from 4 to 10 wt %, for further study. The SEM images showed that when the concentrations of PS nanospheres in the solution were 6 and 8 wt %, the matrixes of the PS nanosphere masks were more uniform than those of 4 and 10 wt %. The effects of the one-side lifting angle of substrates and the vaporization temperature for the solvent of one-layer self-assembly PS nanosphere thin films, were also investigated. Finally, the concentration of the nano-scale PS nanospheres in the solution was set at 8 wt % to form the PS nanosphere masks by the drop-coating method. Three different physical deposition methods, including thermal evaporation, radio-frequency magnetron sputtering, and e-gun deposition, were used to deposit the Au-Ag triangle hexagonal periodic nanoparticle arrays. The SEM images showed that as the single-layer PS nanosphere mask was well controlled, the thermal evaporation could deposit the Au-Ag triangle hexagonal nanoparticle arrays with a higher quality than the other two methods.

High-yielding and photolabile approaches to the covalent attachment of biomolecules to surfaces via hydrazone chemistry.

PubMed

Lee, Ju Hun; Domaille, Dylan W; Noh, Hyunwoo; Oh, Taeseok; Choi, Chulmin; Jin, Sungho; Cha, Jennifer N

2014-07-22

The development of strategies to couple biomolecules covalently to surfaces is necessary for constructing sensing arrays for biological and biomedical applications. One attractive conjugation reaction is hydrazone formation--the reaction of a hydrazine with an aldehyde or ketone--as both hydrazines and aldehydes/ketones are largely bioorthogonal, which makes this particular reaction suitable for conjugating biomolecules to a variety of substrates. We show that the mild reaction conditions afforded by hydrazone conjugation enable the conjugation of DNA and proteins to the substrate surface in significantly higher yields than can be achieved with traditional bioconjugation techniques, such as maleimide chemistry. Next, we designed and synthesized a photocaged aryl ketone that can be conjugated to a surface and photochemically activated to provide a suitable partner for subsequent hydrazone formation between the surface-anchored ketone and DNA- or protein-hydrazines. Finally, we exploit the latent functionality of the photocaged ketone and pattern multiple biomolecules on the same substrate, effectively demonstrating a strategy for designing substrates with well-defined domains of different biomolecules. We expect that this approach can be extended to the production of multiplexed assays by using an appropriate mask with sequential photoexposure and biomolecule conjugation steps.

Development of EUV mask handling technology at MIRAI-Selete

NASA Astrophysics Data System (ADS)

Ota, Kazuya; Amemiya, Mitsuaki; Taguchi, Takao; Kamono, Takashi; Kubo, Hiroyoshi; Takikawa, Tadahiko; Usui, Yoichi; Suga, Osamu

2007-03-01

We, MIRAI-Selete, started a new EUV mask program in April, 2006. Development of EUV mask handling technology is one of the key areas of the program. We plan to develop mask handling technology and to evaluate EUV mask carriers using Lasertec M3350, a particle inspection tool with the defect sensitivity less than 50nm PSL, and Mask Protection Engineering Tool (named "MPE Tool"). M3350 is a newly developed tool based on a conventional M1350 for EUV blanks inspection. Since our M3350 has a blank flipping mechanism in it, we can inspect the front and the back surface of the blank automatically. We plan to use the M3350 for evaluating particle adders during mask shipping, storage and handling. MPE Tool is a special tool exclusively developed for demonstration of pellicleless mask handling. It can handle a mask within a protective enclosure, which Canon and Nikon have been jointly proposing1, and also, can be modified to handle other type of carrier as the need arises.

Hierarchically ordered carbon tubes

NASA Astrophysics Data System (ADS)

Pan, Zheng-Wei; Zhu, Hao-Guo; Zhang, Zong-Tao; Im, Hee-Jung; Dai, Sheng; Beach, David B.; Lowndes, Douglas H.

2003-04-01

Micropatterns of hierarchically ordered carbon tubes (i.e., ordered carbon microtubes composed of aligned carbon nanotubes) were grown on a film-like iron/silica substrate consisting of ring-like catalyst patterns. The substrates were prepared by a combined technique, in which the sol-gel method was used to prepare catalyst film and transmission electron microscope grids were used as a shadow mask. In comparison with other techniques that involve sophisticated lithography, this approach represents a simple and low-cost way to the micropatterning of aligned carbon nanotubes.

Fiber Optic Couplers.

DTIC Science & Technology

1979-11-01

over a 1 x 4 inch glass plate. A further problem has been that the surface over the ion diffused region is submerged 2 pm below that of the substrate...of varying mask openings (35, 45, 55, 65, 78, 85 pm ). The ion exchange processing time was varied using 20, 25, 35 and 40 minutes. We found that the...pattern is then overcoated with a thick layer of SiO 2 (lO0 pm thick). This thick layer and the SiO 2 substrate thus com- pletely surround the dopant

Bottom-up photonic crystal cavities formed by patterned III-V nanopillars.

PubMed

Scofield, Adam C; Shapiro, Joshua N; Lin, Andrew; Williams, Alex D; Wong, Ping-Show; Liang, Baolai L; Huffaker, Diana L

2011-06-08

We report on the formation and optical properties of bottom-up photonic crystal (PC) cavities formed by III-V nanopillars (NPs) via catalyst-free selective-area metal-organic chemical vapor deposition on masked GaAs substrates. This method of NP synthesis allows for precise lithographic control of NP position and diameter enabling simultaneous formation of both the photonic band gap (PBG) region and active gain region. The PBG and cavity resonance are determined by independently tuning the NP radius r, pitch a, and height h in the respective masked areas. Near-infrared emission at 970 nm is achieved from axial GaAs/InGaAs heterostructures with in situ passivation by laterally grown InGaP shells. To achieve out-of-plane optical confinement, the PC cavities are embedded in polydimethylsiloxane (PDMS) and removed from the growth substrate. Spatially and spectrally resolved 77 K photoluminescence demonstrates a strong influence of the PBG resonance on device emission. Resonant peaks are observed in the emission spectra of PC cavities embedded in PDMS.

Masked PDAMNA Film On Glass

NASA Technical Reports Server (NTRS)

1996-01-01

Polydiacetylenes are a unique class of highly conjugated organic polymers that are of interest for both electronic and photonic applications. Photodeposition from solutions is a novel process superior to those grown by conventional techniques. Evidence of this is seen when the films are viewed under a microscope; they exhibit small particles of solid polymer which form in the bulk solution, get transported by convection to the surface of the growing film, and become embedded. Also convection tends to cause the film thickness to be less uniform, and may even affect the molecular orientation of the films. The thrust of the research is to investigate in detail, both in 1-g and low-g, the effects of convection (and lack thereof) on this novel and interesting reaction. In this example, a portion of the substrate was blocked from exposure to the UV light by the mask, which was placed on the opposite side of the glass disk as the film, clearly demonstrating that photodeposition occurs only where the substrate is irradiated directly.

Advanced detectors and signal processing

NASA Technical Reports Server (NTRS)

Greve, D. W.; Rasky, P. H. L.; Kryder, M. H.

1986-01-01

Continued progress is reported toward development of a silicon on garnet technology which would allow fabrication of advanced detection and signal processing circuits on bubble memories. The first integrated detectors and propagation patterns have been designed and incorporated on a new mask set. In addition, annealing studies on spacer layers are performed. Based on those studies, a new double layer spacer is proposed which should reduce contamination of the silicon originating in the substrate. Finally, the magnetic sensitivity of uncontaminated detectors from the last lot of wafers is measured. The measured sensitivity is lower than anticipated but still higher than present magnetoresistive detectors.

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

NASA Astrophysics Data System (ADS)

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

2015-10-01

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

Apparatus and processes for the mass production of photovoltaic modules

DOEpatents

Barth, Kurt L [Ft. Collins, CO; Enzenroth, Robert A [Fort Collins, CO; Sampath, Walajabad S [Fort Collins, CO

2007-05-22

An apparatus and processes for large scale inline manufacturing of CdTe photovoltaic modules in which all steps, including rapid substrate heating, deposition of CdS, deposition of CdTe, CdCl.sub.2 treatment, and ohmic contact formation, are performed within a single vacuum boundary at modest vacuum pressures. A p+ ohmic contact region is formed by subliming a metal salt onto the CdTe layer. A back electrode is formed by way of a low cost spray process, and module scribing is performed by means of abrasive blasting or mechanical brushing through a mask. The vacuum process apparatus facilitates selective heating of substrates and films, exposure of substrates and films to vapor with minimal vapor leakage, deposition of thin films onto a substrate, and stripping thin films from a substrate. A substrate transport apparatus permits the movement of substrates into and out of vacuum during the thin film deposition processes, while preventing the collection of coatings on the substrate transport apparatus itself.

Apparatus and processes for the mass production of photovotaic modules

DOEpatents

Barth, Kurt L.; Enzenroth, Robert A.; Sampath, Walajabad S.

2002-07-23

An apparatus and processes for large scale inline manufacturing of CdTe photovoltaic modules in which all steps, including rapid substrate heating, deposition of CdS, deposition of CdTe, CdCl.sub.2 treatment, and ohmic contact formation, are performed within a single vacuum boundary at modest vacuum pressures. A p+ ohmic contact region is formed by subliming a metal salt onto the CdTe layer. A back electrode is formed by way of a low cost spray process, and module scribing is performed by means of abrasive blasting or mechanical brushing through a mask. The vacuum process apparatus facilitates selective heating of substrates and films, exposure of substrates and films to vapor with minimal vapor leakage, deposition of thin films onto a substrate, and stripping thin films from a substrate. A substrate transport apparatus permits the movement of substrates into and out of vacuum during the thin film deposition processes, while preventing the collection of coatings on the substrate transport apparatus itself.

Characterization of a Surface-Flashover Ion Source with 10-250 ns Pulse Widths

NASA Astrophysics Data System (ADS)

Falabella, S.; Guethlein, G.; Kerr, P. L.; Meyer, G. A.; Morse, J. D.; Sampayan, S.; Tang, V.

2009-03-01

As a step towards developing an ultra compact D-D neutron source for various defense and homeland security applications, a compact ion source is needed. Towards that end, we are testing a pulsed, surface flashover source, with deuterated titanium films deposited on alumina substrates as the electrodes. An electrochemically-etched mask was used to define the electrode areas on the substrate during the sputtered deposition of the titanium films. Deuterium loading of the films was performed in an all metal-sealed vacuum chamber containing a heated stage. Deuterium ion current from the source was determined by measuring the neutrons produced when the ions impacted a deuterium-loaded target held at -90 kV. As the duration of the arc current is varied, it was observed that the integrated deuteron current per pulse initially increases rapidly, then reaches a maximum near a pulse length of 100 ns.

A strategy for design and fabrication of low cost microchannel for future reproductivity of bio/chemical lab-on-chip application

NASA Astrophysics Data System (ADS)

Humayun, Q.; Hashim, U.; Ruzaidi, C. M.; Noriman, N. Z.

2017-03-01

The fabrication and characterization of sensitive and selective fluids delivery system for the application of nano laboratory on a single chip is a challenging task till to date. This paper is one of the initial attempt to resolve this challenging task by using a simple, cost effective and reproductive technique for pattering a microchannel structures on SU-8 resist. The objective of the research is to design, fabricate and characterize polydimethylsiloxane (PDMS) microchannel. The proposed device mask was designed initially by using AutoCAD software and then the designed was transferred to transparency sheet and to commercial chrome mask for better photo masking process. The standard photolithography process coupled with wet chemical etching process was used for the fabrication of proposed microchannel. This is a low cost fabrication technique for the formation of microchannel structure at resist. The fabrication process start from microchannel formation and then the structure was transformed to PDMS substrate, the microchannel structure was cured from mold and then the cured mold was bonded with the glass substrate by plasma oxidation bonding process. The surface morphology was characterized by high power microscope (HPM) and the structure was characterized by Hawk 3 D surface nanoprofiler. The next part of the research will be focus onto device testing and validation by using real biological samples by the implementation of a simple manual injection technique.

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.

Rapid Stencil Mask Fabrication Enabled One-Step Polymer-Free Graphene Patterning and Direct Transfer for Flexible Graphene Devices

PubMed Central

Yong, Keong; Ashraf, Ali; Kang, Pilgyu; Nam, SungWoo

2016-01-01

We report a one-step polymer-free approach to patterning graphene using a stencil mask and oxygen plasma reactive-ion etching, with a subsequent polymer-free direct transfer for flexible graphene devices. Our stencil mask is fabricated via a subtractive, laser cutting manufacturing technique, followed by lamination of stencil mask onto graphene grown on Cu foil for patterning. Subsequently, micro-sized graphene features of various shapes are patterned via reactive-ion etching. The integrity of our graphene after patterning is confirmed by Raman spectroscopy. We further demonstrate the rapid prototyping capability of a stretchable, crumpled graphene strain sensor and patterned graphene condensation channels for potential applications in sensing and heat transfer, respectively. We further demonstrate that the polymer-free approach for both patterning and transfer to flexible substrates allows the realization of cleaner graphene features as confirmed by water contact angle measurements. We believe that our new method promotes rapid, facile fabrication of cleaner graphene devices, and can be extended to other two dimensional materials in the future. PMID:27118249

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.

Fabrication of silicon films from patterned protruded seeds

NASA Astrophysics Data System (ADS)

Zeng, Huang; Zhang, Wei; Li, Jizhou; Wang, Cong; Yang, Hui; Chen, Yigang; Chen, Xiaoyuan; Liu, Dongfang

2017-05-01

Thin, flexible silicon crystals are starting up applications such as light-weighted flexible solar cells, SOI, flexible IC chips, 3D ICs imagers and 3D CMOS imagers on the demand of high performance with low cost. Kerfless wafering technology by direct conversion of source gases into mono-crystalline wafers on reusable substrates is highly cost-effective and feedstock-effective route to cheap wafers with the thickness down to several microns. Here we show a prototype for direct conversion of silicon source gases to wafers by using the substrate with protruded seeds. A reliable and controllable method of wafer-scaled preparation of protruded seed patterns has been developed by filling liquid wax into a rod array as the mask for the selective removal of oxide layer on the rod head. Selectively epitaxial growth is performed on the protruded seeds, and the voidless film is formed by the merging of neighboring seeds through growing. And structured hollows are formed between the grown film and the substrate, which would offer the transferability of the grown film and the reusability of the protruded seeds.

The pilus usher controls protein interactions via domain masking and is functional as an oligomer.

PubMed

Werneburg, Glenn T; Henderson, Nadine S; Portnoy, Erica B; Sarowar, Samema; Hultgren, Scott J; Li, Huilin; Thanassi, David G

2015-07-01

The chaperone-usher (CU) pathway assembles organelles termed pili or fimbriae in Gram-negative bacteria. Type 1 pili expressed by uropathogenic Escherichia coli are prototypical structures assembled by the CU pathway. Biogenesis of pili by the CU pathway requires a periplasmic chaperone and an outer-membrane protein termed the usher (FimD). We show that the FimD C-terminal domains provide the high-affinity substrate-binding site but that these domains are masked in the resting usher. Domain masking requires the FimD plug domain, which serves as a switch controlling usher activation. We demonstrate that usher molecules can act in trans for pilus biogenesis, providing conclusive evidence for a functional usher oligomer. These results reveal mechanisms by which molecular machines such as the usher regulate and harness protein-protein interactions and suggest that ushers may interact in a cooperative manner during pilus assembly in bacteria.

The Pilus Usher Controls Protein Interactions via Domain Masking and is Functional as an Oligomer

PubMed Central

Werneburg, Glenn T.; Henderson, Nadine S.; Portnoy, Erica B.; Sarowar, Samema; Hultgren, Scott J.; Li, Huilin; Thanassi, David G.

2015-01-01

The chaperone-usher (CU) pathway assembles organelles termed pili or fimbriae in Gram-negative bacteria. Type 1 pili expressed by uropathogenic Escherichia coli are prototypical structures assembled by the CU pathway. Biogenesis of pili by the CU pathway requires a periplasmic chaperone and an outer membrane protein termed the usher (FimD). We show that the FimD C-terminal domains provide the high-affinity substrate binding site, but that these domains are masked in the resting usher. Domain masking requires the FimD plug domain, which serves as a switch controlling usher activation. We demonstrate that usher molecules can act in trans for pilus biogenesis, providing conclusive evidence for a functional usher oligomer. These results reveal mechanisms by which molecular machines such as the usher regulate and harness protein-protein interactions, and suggest that ushers may interact in a cooperative manner during pilus assembly in bacteria. PMID:26052892

Femtopulse laser-based mask repair in the DUV wavelength regime

NASA Astrophysics Data System (ADS)

Ghadiali, Firoz; Tolani, Vikram; Nagpal, Rajesh; Robinson, Tod; LeClaire, Jeff; Bozak, Ron; Lee, David A.; White, Roy

2006-05-01

Deep ultraviolet (DUV) femtosecond-pulsed laser ablation has numerous highly desirable properties for subtractive photomask defect repair. These qualities include high removal rates, resolution better than the focused spot size, minimized redeposition of the ablated material (rollup and splatter), and a negligible heat affected zone. The optical properties of the photomask result in a broad repair process window because the absorber film (whether Cr or MoSi) and the transmissive substrate allow for a high degree of material removal selectivity. Repair results and process parameters from such a system are examined in light of theoretical considerations. In addition, the practical aspects of the operation of this system in a production mask house environment are reviewed from the standpoint of repair quality, capability, availability, and throughput. Focus is given to the benefit received by the mask shop, and to the technical performance of the system.

Method to fabricate a tilted logpile photonic crystal

DOEpatents

Williams, John D.; Sweatt, William C.

2010-10-26

A method to fabricate a tilted logpile photonic crystal requires only two lithographic exposures and does not require mask repositioning between exposures. The mask and photoresist-coated substrate are spaced a fixed and constant distance apart using a spacer and the stack is clamped together. The stack is then tilted at a crystallographic symmetry angle (e.g., 45 degrees) relative to the X-ray beam and rotated about the surface normal until the mask is aligned with the X-ray beam. The stack is then rotated in plane by a small stitching angle and exposed to the X-ray beam to pattern the first half of the structure. The stack is then rotated by 180.degree. about the normal and a second exposure patterns the remaining half of the structure. The method can use commercially available DXRL scanner technology and LIGA processes to fabricate large-area, high-quality tilted logpile photonic crystals.

Low thermal distortion Extreme-UV lithography reticle and method

DOEpatents

Gianoulakis, Steven E.; Ray-Chaudhuri, Avijit K.

2002-01-01

Thermal distortion of reticles or masks can be significantly reduced by emissivity engineering, i.e., the selective placement or omission of coatings on the reticle. Reflective reticles so fabricated exhibit enhanced heat transfer thereby reducing the level of thermal distortion and ultimately improving the quality of the transcription of the reticle pattern onto the wafer. Reflective reticles include a substrate having an active region that defines the mask pattern and non-active region(s) that are characterized by a surface that has a higher emissivity than that of the active region. The non-active regions are not coated with the radiation reflective material.

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

NASA Astrophysics Data System (ADS)

Kimmel, Kurt R.; Hughes, Patrick J.

1996-05-01

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

Pressure Ulcer Incidence in Patients Wearing Nasal-Oral Versus Full-Face Noninvasive Ventilation Masks.

PubMed

Schallom, Marilyn; Cracchiolo, Lisa; Falker, Antoinette; Foster, Jennifer; Hager, JoAnn; Morehouse, Tamara; Watts, Peggy; Weems, Linda; Kollef, Marin

2015-07-01

Device-related pressure ulcers from noninvasive ventilation masks alter skin integrity and cause patients discomfort. To examine the incidence, location, and stage of pressure ulcers and patients' comfort with a nasal-oral mask compared with a full-face mask. A before-after study of a convenience sample of patients with noninvasive ventilation orders in 5 intensive care units was conducted. Two groups of 100 patients each received either the nasal-oral mask or the full-face mask. Skin was assessed before the mask was applied and every 12 hours after that or upon mask removal. Comfort levels were assessed every 12 hours on a Likert scale of 1 to 5 (1, most comfortable). A pressure ulcer developed in 20% of patients in the nasal-oral mask group and 2% of patients in the full-face mask group (P < .001). Comfort scores were significantly lower (more comfortable) with the full-face mask (mean [SD], 1.9 [1.1]) than with the nasal-oral mask (mean [SD], 2.7 [1.2], P < .001). Neither mean hours worn nor percentage adherence differed significantly: 28.9 (SD, 27.2) hours and 92% for full-face mask and 25 (SD, 20.7) and 92% for nasal-oral mask. No patients who had a pressure ulcer develop with the nasal-oral mask had a pressure ulcer develop with the full-face mask. The full-face mask resulted in significantly fewer pressure ulcers and was more comfortable for patients. The full-face mask is a reasonable alternative to traditional nasal-oral masks for patients receiving noninvasive ventilation. ©2015 American Association of Critical-Care Nurses.

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.

Optimization of plasma etching of SiO2 as hard mask for HgCdTe dry etching

NASA Astrophysics Data System (ADS)

Chen, Yiyu; Ye, Zhenhua; Sun, Changhong; Zhang, Shan; Xin, Wen; Hu, Xiaoning; Ding, Ruijun; He, Li

2016-10-01

HgCdTe is one of the dominating materials for infrared detection. To pattern this material, our group has proven the feasibility of SiO2 as a hard mask in dry etching process. In recent years, the SiO2 mask patterned by plasma with an auto-stopping layer of ZnS sandwiched between HgCdTe and SiO2 has been developed by our group. In this article, we will report the optimization of SiO2 etching on HgCdTe. The etching of SiO2 is very mature nowadays. Multiple etching recipes with deferent gas mixtures can be used. We utilized a recipe containing Ar and CHF3. With strictly controlled photolithography, the high aspect-ratio profile of SiO2 was firstly achieved on GaAs substrate. However, the same recipe could not work well on MCT because of the low thermal conductivity of HgCdTe and CdTe, resulting in overheated and deteriorated photoresist. By decreasing the temperature, the photoresist maintained its good profile. A starting table temperature around -5°C worked well enough. And a steep profile was achieved as checked by the SEM. Further decreasing of temperature introduced profile with beveled corner. The process window of the temperature is around 10°C. Reproducibility and uniformity were also confirmed for this recipe.

Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

DOEpatents

Braunlich, Peter F.; Tetzlaff, Wolfgang

1989-01-01

Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phoshphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate.

EUVL Mask Blank Repair

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

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

2002-05-22

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

Polyelectrolyte multilayer-assisted fabrication of non-periodic silicon nanocolumn substrates for cellular interface applications

NASA Astrophysics Data System (ADS)

Lee, Seyeong; Kim, Dongyoon; Kim, Seong-Min; Kim, Jeong-Ah; Kim, Taesoo; Kim, Dong-Yu; Yoon, Myung-Han

2015-08-01

Recent advances in nanostructure-based biotechnology have resulted in a growing demand for vertical nanostructure substrates with elaborate control over the nanoscale geometry and a high-throughput preparation. In this work, we report the fabrication of non-periodic vertical silicon nanocolumn substrates via polyelectrolyte multilayer-enabled randomized nanosphere lithography. Owing to layer-by-layer deposited polyelectrolyte adhesives, uniformly-separated polystyrene nanospheres were securely attached on large silicon substrates and utilized as masks for the subsequent metal-assisted silicon etching in solution. Consequently, non-periodic vertical silicon nanocolumn arrays were successfully fabricated on a wafer scale, while each nanocolumn geometric factor, such as the diameter, height, density, and spatial patterning, could be fully controlled in an independent manner. Finally, we demonstrate that our vertical silicon nanocolumn substrates support viable cell culture with minimal cell penetration and unhindered cell motility due to the blunt nanocolumn morphology. These results suggest that vertical silicon nanocolumn substrates may serve as a useful cellular interface platform for performing a statistically meaningful number of cellular experiments in the fields of biomolecular delivery, stem cell research, etc.Recent advances in nanostructure-based biotechnology have resulted in a growing demand for vertical nanostructure substrates with elaborate control over the nanoscale geometry and a high-throughput preparation. In this work, we report the fabrication of non-periodic vertical silicon nanocolumn substrates via polyelectrolyte multilayer-enabled randomized nanosphere lithography. Owing to layer-by-layer deposited polyelectrolyte adhesives, uniformly-separated polystyrene nanospheres were securely attached on large silicon substrates and utilized as masks for the subsequent metal-assisted silicon etching in solution. Consequently, non-periodic vertical silicon nanocolumn arrays were successfully fabricated on a wafer scale, while each nanocolumn geometric factor, such as the diameter, height, density, and spatial patterning, could be fully controlled in an independent manner. Finally, we demonstrate that our vertical silicon nanocolumn substrates support viable cell culture with minimal cell penetration and unhindered cell motility due to the blunt nanocolumn morphology. These results suggest that vertical silicon nanocolumn substrates may serve as a useful cellular interface platform for performing a statistically meaningful number of cellular experiments in the fields of biomolecular delivery, stem cell research, etc. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02384j

Flexible, transparent and highly sensitive SERS substrates with cross-nanoporous structures for fast on-site detection.

PubMed

Wang, Yingcheng; Jin, Yuanhao; Xiao, Xiaoyang; Zhang, Tianfu; Yang, Haitao; Zhao, Yudan; Wang, Jiaping; Jiang, Kaili; Fan, Shoushan; Li, Qunqing

2018-05-30

A flexible and transparent film assembled from the cross-nanoporous structures of Au on PET (CNS of Au@PET) is developed as a versatile and effective SERS substrate for rapid, on-site trace analysis with high sensitivity. The fabrication of the CNS of Au can be achieved on a large scale at low cost by employing an etching process with super-aligned carbon nanotubes as a mask, followed by metal deposition. A strongly enhanced Raman signal with good uniformity can be obtained, which is attributed to the excitation of "hot spots" around the metal nanogaps and sharp edges. Using the CNS of Au@PET film as a SERS platform, real-time and on-site SERS detection of the food contaminant crystal violet (CV) is achieved, with a detection limit of CV solution on a tomato skin of 10-7 M. Owing to its ability to efficiently extract trace analytes, the resulting substrate also achieves detection of 4-ATP contaminants and thiram pesticides by swabbing the skin of an apple. A SERS detection signal for 4-ATP has a relative standard deviation of less than 10%, revealing the excellent reproducibility of the substrate. The flexible, transparent and highly sensitive substrates fabricated using this simple and cost-effective strategy are promising for practical application in rapid, on-site SERS-based detection.

Electrostatic particle trap for ion beam sputter deposition

DOEpatents

Vernon, Stephen P.; Burkhart, Scott C.

2002-01-01

A method and apparatus for the interception and trapping of or reflection of charged particulate matter generated in ion beam sputter deposition. The apparatus involves an electrostatic particle trap which generates electrostatic fields in the vicinity of the substrate on which target material is being deposited. The electrostatic particle trap consists of an array of electrode surfaces, each maintained at an electrostatic potential, and with their surfaces parallel or perpendicular to the surface of the substrate. The method involves interception and trapping of or reflection of charged particles achieved by generating electrostatic fields in the vicinity of the substrate, and configuring the fields to force the charged particulate material away from the substrate. The electrostatic charged particle trap enables prevention of charged particles from being deposited on the substrate thereby enabling the deposition of extremely low defect density films, such as required for reflective masks of an extreme ultraviolet lithography (EUVL) system.

Large Coded Aperture Mask for Spaceflight Hard X-ray Images

NASA Technical Reports Server (NTRS)

Vigneau, Danielle N.; Robinson, David W.

2002-01-01

The 2.6 square meter coded aperture mask is a vital part of the Burst Alert Telescope on the Swift mission. A random, but known pattern of more than 50,000 lead tiles, each 5 mm square, was bonded to a large honeycomb panel which projects a shadow on the detector array during a gamma ray burst. A two-year development process was necessary to explore ideas, apply techniques, and finalize procedures to meet the strict requirements for the coded aperture mask. Challenges included finding a honeycomb substrate with minimal gamma ray attenuation, selecting an adhesive with adequate bond strength to hold the tiles in place but soft enough to allow the tiles to expand and contract without distorting the panel under large temperature gradients, and eliminating excess adhesive from all untiled areas. The largest challenge was to find an efficient way to bond the > 50,000 lead tiles to the panel with positional tolerances measured in microns. In order to generate the desired bondline, adhesive was applied and allowed to cure to each tile. The pre-cured tiles were located in a tool to maintain positional accuracy, wet adhesive was applied to the panel, and it was lowered to the tile surface with synchronized actuators. Using this procedure, the entire tile pattern was transferred to the large honeycomb panel in a single bond. The pressure for the bond was achieved by enclosing the entire system in a vacuum bag. Thermal vacuum and acoustic tests validated this approach. This paper discusses the methods, materials, and techniques used to fabricate this very large and unique coded aperture mask for the Swift mission.

The technical consideration of multi-beam mask writer for production

NASA Astrophysics Data System (ADS)

Lee, Sang Hee; Ahn, Byung-Sup; Choi, Jin; Shin, In Kyun; Tamamushi, Shuichi; Jeon, Chan-Uk

2016-10-01

Multi-beam mask writer is under development to solve the throughput and patterning resolution problems in VSB mask writer. Theoretically, the writing time is appropriate for future design node and the resolution is improved with multi-beam mask writer. Many previous studies show the feasible results of resolution, CD control and registration. Although such technical results of development tool seem to be enough for mass production, there are still many unexpected problems for real mass production. In this report, the technical challenges of multi-beam mask writer are discussed in terms of production and application. The problems and issues are defined based on the performance of current development tool compared with the requirements of mask quality. Using the simulation and experiment, we analyze the specific characteristics of electron beam in multi-beam mask writer scheme. Consequently, we suggest necessary specifications for mass production with multi-beam mask writer in the future.

Bioinspired broadband antireflection coatings on GaSb

NASA Astrophysics Data System (ADS)

Min, Wei-Lun; Betancourt, Amaury P.; Jiang, Peng; Jiang, Bin

2008-04-01

We report an inexpensive yet scalable templating technique for fabricating moth-eye antireflection gratings on gallium antimonide substrates. Non-close-packed colloidal monolayers are utilized as etching masks to pattern subwavelength-structured nipple arrays on GaSb. The resulting gratings exhibit superior broadband antireflection properties and thermal stability than conventional multilayer dielectric coatings. The specular reflection of the templated nipple arrays match with the theoretical predictions using a rigorous coupled-wave analysis model. The effect of the nipple shape and size on the antireflection properties has also been investigated by the same model. These biomimetic coatings are of great technological importance in developing efficient thermophotovoltaic cells.

SEMICONDUCTOR TECHNOLOGY: Reduction of proximity effect in fabricating nanometer-spaced nanopillars by two-step exposure

NASA Astrophysics Data System (ADS)

Yang, Zhang; Renping, Zhang; Weihua, Han; Jian, Liu; Xiang, Yang; Ying, Wang; Chian Chiu, Li; Fuhua, Yang

2009-11-01

A two-step exposure method to effectively reduce the proximity effect in fabricating nanometer-spaced nanopillars is presented. In this method, nanopillar patterns on poly-methylmethacrylate (PMMA) were partly cross-linked in the first-step exposure. After development, PMMA between nanopillar patterns was removed, and hence the proximity effect would not take place there in the subsequent exposure. In the second-step exposure, PMMA masks were completely cross-linked to achieve good resistance in inductively coupled plasma etching. Accurate pattern transfer of rows of nanopillars with spacing down to 40 nm was realized on a silicon-on-insulator substrate.

Combinatorial preparation and characterization of thin-film multilayer electro-optical devices.

PubMed

Neuber, Christian; Bäte, Markus; Thelakkat, Mukundan; Schmidt, Hans-Werner; Hänsel, Helmut; Zettl, Heiko; Krausch, Georg

2007-07-01

In this article we present a setup for the combinatorial vapor deposition of thin-film multilayer devices as well as methods for the fast and efficient analytic screening of the libraries obtained. The preparation setup is based on a commercially available evaporation chamber equipped with various evaporation sources for both organic and metallic materials. The combinatorial approach is realized by the combination of a rotation stage for the substrate, a five-mask sampler, and an additional mask whose position can be deliberately varied along one axis during the evaporation process. The latter is used to evaporate linear as well as step gradients by continuous or stepwise movement of a shutter mask. The mask sampler allows to define the sectors of the library and to evaporate more complex structures, e.g., an electrode layout. Finally, the simultaneous evaporation of two or more materials enables us to produce layers of varying composition ratio in general and doped materials, in particular. For the control of the evaporation process we have developed an automation software, which is particularly helpful for complex library designs and which grants excellent repeatability of experiments. Efficient and fast characterization of the obtained libraries is realized by (i) a purely optical setup and (ii) an electro-optical setup. (i) The UV/vis reader FLASHScan 530 permits to map out the UV/vis absorbance or fluorescence of the whole library. The UV/vis absorbance is primarily used to determine layer thicknesses and to confirm thickness uniformity across larger regions. The fluorescence measurements are used to determine the composition of layers containing fluorescent dyes. (ii) For a detailed short- and long-term electro-optical analysis we have developed an automated measurement system, which allows the characterization of 8x8 optoelectronic devices and to study their degradation behavior. Both solar cells and organic light-emitting diodes can be tested. Finally, we have developed a data analysis software to extract characteristic values from the huge amount of data and with this facilitate the finding of systematic dependencies.

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

Upadhyaya, Mihir; Jindal, Vibhu; Basavalingappa, Adarsh

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

High-Resolution Inkjet-Printed Oxide Thin-Film Transistors with a Self-Aligned Fine Channel Bank Structure.

PubMed

Zhang, Qing; Shao, Shuangshuang; Chen, Zheng; Pecunia, Vincenzo; Xia, Kai; Zhao, Jianwen; Cui, Zheng

2018-05-09

A self-aligned inkjet printing process has been developed to construct small channel metal oxide (a-IGZO) thin-film transistors (TFTs) with independent bottom gates on transparent glass substrates. Poly(methylsilsesquioxane) was used to pattern hydrophobic banks on the transparent substrate instead of commonly used self-assembled octadecyltrichlorosilane. Photolithographic exposure from backside using bottom-gate electrodes as mask formed hydrophilic channel areas for the TFTs. IGZO ink was selectively deposited by an inkjet printer in the hydrophilic channel region and confined by the hydrophobic bank structure, resulting in the precise deposition of semiconductor layers just above the gate electrodes. Inkjet-printed IGZO TFTs with independent gate electrodes of 10 μm width have been demonstrated, avoiding completely printed channel beyond the broad of the gate electrodes. The TFTs showed on/off ratios of 10 8 , maximum mobility of 3.3 cm 2 V -1 s -1 , negligible hysteresis, and good uniformity. This method is conductive to minimizing the area of printed TFTs so as to the development of high-resolution printing displays.

Thin-Film Nanocapacitor and Its Characterization

ERIC Educational Resources Information Center

Hunter, David N.; Pickering, Shawn L.; Jia, Dongdong

2007-01-01

An undergraduate thin-film nanotechnology laboratory was designed. Nanocapacitors were fabricated on silicon substrates by sputter deposition. A mask was designed to form the shape of the capacitor and its electrodes. Thin metal layers of Au with a 80 nm thickness were deposited and used as two infinitely large parallel plates for a capacitor.…

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

Dong, Rui; Moore, Logan; Ocola, Leonidas E.

The mask-free patterning technique is employed to fabricate arrays of MoS2 and WS2 structures on silicon and graphene substrates with quality interfaces. By depositing precursor inks with the AFM cantilevers and subsequent heat treatment in the CVD furnace, it is demonstrated that MoS2 and WS2 structures can be formed on graphene surfaces at predefined device architectures.

Irradiation resistance of intravolume shading elements embedded in photomasks used for CD uniformity control by local intra-field transmission attenuation

NASA Astrophysics Data System (ADS)

Zait, Eitan; Ben-Zvi, Guy; Dmitriev, Vladimir; Oshemkov, Sergey; Pforr, Rainer; Hennig, Mario

2006-05-01

Intra-field CD variation is, besides OPC errors, a main contributor to the total CD variation budget in IC manufacturing. It is caused mainly by mask CD errors. In advanced memory device manufacturing the minimum features are close to the resolution limit resulting in large mask error enhancement factors hence large intra-field CD variations. Consequently tight CD Control (CDC) of the mask features is required, which results in increasing significantly the cost of mask and hence the litho process costs. Alternatively there is a search for such techniques (1) which will allow improving the intrafield CD control for a given moderate mask and scanner imaging performance. Currently a new technique (2) has been proposed which is based on correcting the printed CD by applying shading elements generated in the substrate bulk of the mask by ultrashort pulsed laser exposure. The blank transmittance across a feature is controlled by changing the density of light scattering pixels. The technique has been demonstrated to be very successful in correcting intra-field CD variations caused by the mask and the projection system (2). A key application criterion of this technique in device manufacturing is the stability of the absorbing pixels against DUV light irradiation being applied during mask projection in scanners. This paper describes the procedures and results of such an investigation. To do it with acceptable effort a special experimental setup has been chosen allowing an evaluation within reasonable time. A 193nm excimer laser with pulse duration of 25 ns has been used for blank irradiation. Accumulated dose equivalent to 100,000 300 mm wafer exposures has been applied to Half Tone PSM mask areas with and without CDC shadowing elements. This allows the discrimination of effects appearing in treated and untreated glass regions. Several intensities have been investigated to define an acceptable threshold intensity to avoid glass compaction or generation of color centers in the glass. The impact of the irradiation on the mask transmittance of both areas has been studied by measurements of the printed CD on wafer using a wafer scanner before and after DUV irradiation.

Nanomesh of Cu fabricated by combining nanosphere lithography and high power pulsed magnetron sputtering and a preliminary study about its function

NASA Astrophysics Data System (ADS)

Xie, Wanchuan; Chen, Jiang; Jiang, Lang; Yang, Ping; Sun, Hong; Huang, Nan

2013-10-01

The Cu nanomesh was obtained by a combination of nanosphere lithography (NSL) and high power pulsed magnetron sputtering (HiPPMS). A deposition mask was formed on TiO2 substrates by the self-assembly of polystyrene latex spheres with a diameter of 1 μm, then Cu nanomesh structure was produced on the substrate using sputtering. The structures were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results show the increase of temperature of the polystyrene mask caused by the thermal radiation from the target and the bombardment of sputtering particles would affect the quality of the final nanopattern. The tests of photocatalytic degradation, platelet adhesion and human umbilical artery smooth muscle cells (HUASMCs) culture show Cu deposition could promote the photocatalytic efficiency of TiO2, affect platelet adhesion and inhibit smooth muscle cell adhesion and proliferation. It is highlighted that these findings may serve as a guide for the research of multifunctional surface structure.

Microminiature optical waveguide structure and method for fabrication

DOEpatents

Strand, O.T.; Deri, R.J.; Pocha, M.D.

1998-12-08

A method for manufacturing low-cost, nearly circular cross section waveguides comprises starting with a substrate material that a molten waveguide material can not wet or coat. A thin layer is deposited of an opposite material that the molten waveguide material will wet and is patterned to describe the desired surface-contact path pedestals for a waveguide. A waveguide material, e.g., polymer or doped silica, is deposited. A resist material is deposited and unwanted excess is removed to form pattern masks. The waveguide material is etched away to form waveguide precursors and the masks are removed. Heat is applied to reflow the waveguide precursors into near-circular cross-section waveguides that sit atop the pedestals. The waveguide material naturally forms nearly circular cross sections due to the surface tension effects. After cooling, the waveguides will maintain the round shape. If the width and length are the same, then spherical ball lenses are formed. Alternatively, the pedestals can be patterned to taper along their lengths on the surface of the substrate. This will cause the waveguides to assume a conical taper after reflowing by heat. 32 figs.

Microminiature optical waveguide structure and method for fabrication

DOEpatents

Strand, Oliver T.; Deri, Robert J.; Pocha, Michael D.

1998-01-01

A method for manufacturing low-cost, nearly circular cross section waveguides comprises starting with a substrate material that a molten waveguide material can not wet or coat. A thin layer is deposited of an opposite material that the molten waveguide material will wet and is patterned to describe the desired surface-contact path pedestals for a waveguide. A waveguide material, e.g., polymer or doped silica, is deposited. A resist material is deposited and unwanted excess is removed to form pattern masks. The waveguide material is etched away to form waveguide precursors and the masks are removed. Heat is applied to reflow the waveguide precursors into near-circular cross-section waveguides that sit atop the pedestals. The waveguide material naturally forms nearly circular cross sections due to the surface tension effects. After cooling, the waveguides will maintain the round shape. If the width and length are the same, then spherical ball lenses are formed. Alternatively, the pedestals can be patterned to taper along their lengths on the surface of the substrate. This will cause the waveguides to assume a conical taper after reflowing by heat.

Etching nano-holes in silicon carbide using catalytic platinum nano-particles

NASA Astrophysics Data System (ADS)

Moyen, E.; Wulfhekel, W.; Lee, W.; Leycuras, A.; Nielsch, K.; Gösele, U.; Hanbücken, M.

2006-09-01

The catalytic reaction of platinum during a hydrogen etching process has been used to perform controlled vertical nanopatterning of silicon carbide substrates. A first set of experiments was performed with platinum powder randomly distributed on the SiC surface. Subsequent hydrogen etching in a hot wall reactor caused local atomic hydrogen production at the catalyst resulting in local SiC etching and hole formation. Secondly, a highly regular and monosized distribution of Pt was obtained by sputter deposition of Pt through an Au membrane serving as a contact mask. After the lift-off of the mask, the hydrogen etching revealed the onset of well-controlled vertical patterned holes on the SiC surface.

Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

DOEpatents

Braunlich, P.F.; Tetzlaff, W.

1989-04-25

Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs.

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

NASA Astrophysics Data System (ADS)

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

2006-10-01

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

Improved Method of Manufacturing SiC Devices

NASA Technical Reports Server (NTRS)

Okojie, Robert S.

2005-01-01

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

Immobilization of alkaline phosphatase on solid surface through self-assembled monolayer and by active-site protection.

PubMed

Gao, En-Feng; Kang, Kyung Lhi; Kim, Jeong Hee

2014-06-01

Retaining biological activity of a protein after immobilization is an important issue and many studies reported to enhance the activity of proteins after immobilization. We recently developed a new immobilization method of enzyme using active-site protection and minimization of the cross-links between enzyme and surface with a DNA polymerase as a model system. In this study, we extended the new method to an enzyme with a small mono-substrate using alkaline phosphatase (AP) as another model system. A condition to apply the new method is that masking agents, in this case its own substrate needs to stay at the active-site of the enzyme to be immobilized in order to protect the active-site during the harsh immobilization process. This could be achieved by removal of essential divalent ion, Zn2+ that is required for full enzyme activity of AP from the masking solution while active-site of AP was protected with p-nitrophenyl phosphate (pNPP). Approximately 40% of the solution-phase activity was acquired with active-site protected immobilized AP. In addition to protection active-site of AP, the number of immobilization links was kinetically controlled. When the mole fraction of the activated carboxyl group of the linker molecule in self-assembled monolayer (SAM) of 12-mercaptododecanoic acid and 6-mercapto-1-ethanol was varied, 10% of 12-mercaptododecanoic acid gave the maximum enzyme activity. Approximately 51% increase in enzyme activity of the active-site protected AP was observed compared to that of the unprotected group. It was shown that the concept of active-site protection and kinetic control of the number of covalent immobilization bonds can be extended to enzymes with small mono-substrates. It opens the possibility of further extension of the new methods of active-site protection and kinetic control of immobilization bond to important enzymes used in research and industrial fields.

Wrinkling and Folding on Patched Elastic Surfaces: Modulation of the Chemistry and Pattern Size of Microwrinkled Surfaces.

PubMed

Nogales, Aurora; Del Campo, Adolfo; Ezquerra, Tiberio A; Rodriguez-Hernández, Juan

2017-06-14

An unconventional strategy is proposed that takes advantage of localized high-deformation areas, referred to as folded wrinkles, to produce microstructured elastic surfaces with precisely controlled pattern dimensions and chemical distribution. For that purpose, elastic PDMS substrates were prestretched to a different extent and oxidized in particular areas using a mask. When the stretching was removed, the PDMS substrate exhibited out-of-plane deformations that largely depend on the applied prestretching. Prestretchings below 100% lead to affine deformations in which the treated areas are buckled. On the contrary, prestretchings above ε >100% prior to surface treatment induce the formation of folded wrinkles on those micrometer-size ultraviolet-ozone (UVO) treated areas upon relaxation. As a result, dual periodic wrinkles were formed due to the alternation of highly deformed (folded) and low deformed (buckled) areas. Our strategy is based on the surface treatment at precise positions upon prestretching of the elastic substrate (PDMS). Additionally, this approach can be used to template the formation of wrinkled surfaces by alternating lines of folded wrinkles (valleys) and low-deformed areas (hills). This effect allowed us to precisely tune the shape and distribution of the UVO exposed areas by varying the prestretching direction. Moreover, the wrinkle characteristics, including period and amplitude, exhibit a direct relation to the dimensions of the patterns present in the mask.

Self-Positioned Nanosized Mask for Transparent and Flexible Ferroelectric Polymer Nanodiodes Array.

PubMed

Hyun, Seung; Kwon, Owoong; Choi, Chungryong; Vincent Joseph, Kanniyambatti L; Kim, Yunseok; Kim, Jin Kon

2016-10-12

High density arrays of ferroelectric polymer nanodiodes have gained strong attention for next-generation transparent and flexible nonvolatile resistive memory. Here, we introduce a facile and innovative method to fabricate ferroelectric polymer nanodiode array on an ITO-coated poly(ethylene terephthalate) (PET) substrate by using block copolymer self-assembly and oxygen plasma etching. First, polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) micelles were spin-coated on poly(vinylidene fluoride-ran-trifluoroethylene) copolymer (P(VDF-TrFE)) film/ITO-coated PET substrate. After the sample was immersed in a gold precursor (HAuCl 4 ) containing solution, which strongly coordinates with nitrogen group in P2VP, oxygen plasma etching was performed. During the plasma etching, coordinated gold precursors became gold nanoparticles (GNPs), which successfully acted as self-positioned etching mask to fabricate a high density array of P(VDF-TrFE)) nanoislands with GNP at the top. Each nanoisland shows clearly individual diode property, as confirmed by current-voltage (I-V) curve. Furthermore, due to the transparent and flexible nature of P(VDF-TrFE)) nanoisland as well as the substrate, the P(VDF-TrFE) nanodiode array was highly tranparent, and the diode property was maintained even after a large number of bendings (for instance, 1000 times). The array could be used as the next-generation tranparent and flexible nonvolatile memory device.

Utilizing pulsed laser deposition lateral inhomogeneity as a tool in combinatorial material science.

PubMed

Keller, David A; Ginsburg, Adam; Barad, Hannah-Noa; Shimanovich, Klimentiy; Bouhadana, Yaniv; Rosh-Hodesh, Eli; Takeuchi, Ichiro; Aviv, Hagit; Tischler, Yaakov R; Anderson, Assaf Y; Zaban, Arie

2015-04-13

Pulsed laser deposition (PLD) is widely used in combinatorial material science, as it enables rapid fabrication of different composite materials. Nevertheless, this method was usually limited to small substrates, since PLD deposition on large substrate areas results in severe lateral inhomogeneity. A few technical solutions for this problem have been suggested, including the use of different designs of masks, which were meant to prevent inhomogeneity in the thickness, density, and oxidation state of a layer, while only the composition is allowed to be changed. In this study, a possible way to take advantage of the large scale deposition inhomogeneity is demonstrated, choosing an iron oxide PLD-deposited library with continuous compositional spread (CCS) as a model system. An Fe₂O₃-Nb₂O₅ library was fabricated using PLD, without any mask between the targets and the substrate. The library was measured using high-throughput scanners for electrical, structural, and optical properties. A decrease in electrical resistivity that is several orders of magnitude lower than pure α-Fe₂O₃ was achieved at ∼20% Nb-O (measured at 47 and 267 °C) but only at points that are distanced from the center of the PLD plasma plume. Using hierarchical clustering analysis, we show that the PLD inhomogeneity can be used as an additional degree of freedom, helping, in this case, to achieve iron oxide with much lower resistivity.

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

NASA Astrophysics Data System (ADS)

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

2007-05-01

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

Taming the Wildness of "Trojan-Horse" Peptides by Charge-Guided Masking and Protease-Triggered Demasking for the Controlled Delivery of Antitumor Agents.

PubMed

Shi, Nian-Qiu; Qi, Xian-Rong

2017-03-29

Cell-penetrating peptide (CPP), also called "Trojan Horse" peptide, has become a successful approach to deliver various payloads into cells for achieving the intracellular access. However, the "Trojan Horse" peptide is too wild, not just to "Troy", but rather widely distributed in the body. Thus, there is an urgent need to tame the wildness of "Trojan Horse" peptide for targeted delivery of antineoplastic agents to the tumor site. To achieve this goal, we exploit a masked CPP-doxorubicin conjugate platform for targeted delivery of chemotherapeutic drugs using charge-guided masking and protease-triggered demasking strategies. In this platform, the cell-penetrating function of the positively CPP (d-form nonaarginine) is abrogated by a negatively shielding peptide (masked CPP), and between them is a cleavable substrate peptide by the protease (MMP-2/9). Protease-triggered demasking would occur when the masked CPP reached the MMP-2/9-riched tumor. The CPP-doxorubicin conjugate (CPP-Dox) and the masked CPP-Dox conjugate (mCPP-Dox) were used as models for the evaluation of masking and demasking processes. It was found that exogenous MMP-2/9 could effectively trigger the reversion of CPP-cargo in this conjugate, and this trigger adhered to the Michaelis-Menten kinetics profile. This conjugate was sensitive to the trigger of endogenous MMP-2/9 and could induce enhanced cytotoxicity toward MMP-2/9-rich tumor cells. In vivo antitumor efficacy revealed that this masked conjugate had considerable antitumor activity and could inhibit the tumor growth at a higher level relative to CPP-cargo. Low toxicity in vivo showed the noticeably decreased wildness of this conjugate toward normal tissues and more controllable entry of antitumor agents into "Troy". On the basis of analyses in vitro and in vivo, this mCPP-cargo conjugate delivery system held an improved selectivity toward MMP-2/9-rich tumors and would be a promising strategy for tumor-targeted treatment.

Close-packed monolayer self-assembly of silica nanospheres assisted by infrared irradiation

NASA Astrophysics Data System (ADS)

Minh, Nguyen Van; Hue, Nguyen Thi; Lien, Nghiem Thi Ha; Hoang, Chu Manh

2018-01-01

In this paper, we report on a fast and cost-effective drop coating technique for the self-assembly of silica nano-spheres from a mono-dispersed colloidal suspension into close-packed monolayer (CMP) on hydrophilic single-crystal silicon substrate. The technique includes the self-assembly of silica nano-spheres on slanted silicon substrate and infrared irradiation during evaporation process of the coated droplet. The influence of the substrate slant angle and infrared irradiation on the formation of silica nano-sphere monolayer is investigated. This achievement is promising for various applications, such as a mask layer for nano-sphere lithography that is employed for producing fundamental elements in photonics, plasmonics, and solar cell. [Figure not available: see fulltext.

Straight single-crystalline germanium nanowires and their patterns grown on sol gel prepared gold/silica substrates

NASA Astrophysics Data System (ADS)

Pan, Zheng Wei; Dai, Sheng; Lowndes, Douglas H.

2005-04-01

Straight single-crystalline Ge nanowires with a uniform diameter distribution of 50-80 nm and lengths up to tens of micrometers were grown in a high yield on sol-gel prepared gold/silica substrates by using Ge powder as the Ge source. Detailed electron microscopy analyses show that the nanowires grow through a vapor-liquid-solid growth mechanism with gold nanoparticles located at the nanowire tips. By using transmission electron microscope grids as the shadow mask, the sol-gel technique can be readily adapted to prepare patterned film-like gold/silica substrates, so that regular micropatterns of Ge nanowires were obtained, which could facilitate the integration of Ge nanowires for characterization and devices.

Improved output power of GaN-based light-emitting diodes grown on a nanopatterned sapphire substrate

NASA Astrophysics Data System (ADS)

Chan, Chia-Hua; Hou, Chia-Hung; Tseng, Shao-Ze; Chen, Tsing-Jen; Chien, Hung-Ta; Hsiao, Fu-Li; Lee, Chien-Chieh; Tsai, Yen-Ling; Chen, Chii-Chang

2009-07-01

This letter describes the improved output power of GaN-based light-emitting diodes (LEDs) formed on a nanopatterned sapphire substrate (NPSS) prepared through etching with a self-assembled monolayer of 750-nm-diameter SiO2 nanospheres used as the mask. The output power of NPSS LEDs was 76% greater than that of LEDs on a flat sapphire substrate. Three-dimensional finite-difference time-domain calculation predicted a 40% enhancement in light extraction efficiency of NPSS LEDs. In addition, the reduction of full widths at half maximum in the ω-scan rocking curves for the (0 0 2) and (1 0 2) planes of GaN on NPSS suggested improved crystal quality.

The pilus usher controls protein interactions via domain masking and is functional as an oligomer

DOE PAGES

Werneburg, Glenn T.; Li, Huilin; Henderson, Nadine S.; ...

2015-06-08

The chaperone/usher (CU) pathway is responsible for biogenesis of organelles termed pili or fimbriae in Gram-negative bacteria. Type 1 pili expressed by uropathogenic Escherichia coli are prototypical structures assembled by the CU pathway. Assembly and secretion of pili by the CU pathway requires a dedicated periplasmic chaperone and a multidomain outer membrane protein termed the usher (FimD). We show that the FimD C-terminal domains provide the high-affinity substrate binding site, but that these domains are masked in the resting usher. Domain masking requires the FimD plug domain, which served as a central switch controlling usher activation. In addition, we demonstratemore » that usher molecules can act in trans for pilus biogenesis, providing conclusive evidence for a functional usher oligomer. These results reveal mechanisms by which molecular machines such as the usher regulate and harness protein-protein interactions, and suggest that ushers may interact in a cooperative manner during pilus assembly in bacteria.« less

A mask manufacturer's perspective on maskless lithography

NASA Astrophysics Data System (ADS)

Buck, Peter; Biechler, Charles; Kalk, Franklin

2005-11-01

Maskless Lithography (ML2) is again being considered for use in mainstream CMOS IC manufacturing. Sessions at technical conferences are being devoted to ML2. A multitude of new companies have been formed in the last several years to apply new concepts to breaking the throughput barrier that has in the past prevented ML2 from achieving the cost and cycle time performance necessary to become economically viable, except in rare cases. Has Maskless Lithography's (we used to call it "Direct Write Lithography") time really come? If so, what is the expected impact on the mask manufacturer and does it matter? The lithography tools used today in mask manufacturing are similar in concept to ML2 except for scale, both in throughput and feature size. These mask tools produce highly accurate lithographic images directly from electronic pattern files, perform multi-layer overlay, and mix-n-match across multiple tools, tool types and sites. Mask manufacturers are already accustomed to the ultimate low volume - one substrate per design layer. In order to achieve the economically required throughput, proposed ML2 systems eliminate or greatly reduce some of the functions that are the source of the mask writer's accuracy. Can these ML2 systems meet the demanding lithographic requirements without these functions? ML2 may eliminate the reticle but many of the processes and procedures performed today by the mask manufacturer are still required. Examples include the increasingly complex mask data preparation step and the verification performed to ensure that the pattern on the reticle is accurately representing the design intent. The error sources that are fixed on a reticle are variable with time on an ML2 system. It has been proposed that if ML2 is successful it will become uneconomical to be in the mask business - that ML2, by taking the high profit masks will take all profitability out of mask manufacturing and thereby endanger the entire semiconductor industry. Others suggest that a successful ML2 system solves the mask cost issue and thereby reduces the need and attractiveness of ML2. Are these concerns valid? In this paper we will present a perspective on maskless lithography from the considerable "direct write" experience of a mask manufacturer. We will examine the various business models proposed for ML2 insertion as well as the key technical challenges to achieving simultaneously the throughput and the lithographic quality necessary to become economically viable. We will consider the question of the economic viability of the mask industry in a post-ML2 world and will propose possible models where the mask industry can meaningfully participate.

Development of x-ray mask in Taiwan

NASA Astrophysics Data System (ADS)

Sheu, Jeng Tzong; Su, Shyang

1996-05-01

This paper presents results of using silicon carbide (SiC) and silicon-rich silicon nitride (SiNx) as membrane for X-ray masks in technology of X-ray lithography. Microcrystalline silicon carbide film was deposited on silicon substrate by electron synchrotron resonance plasma-enhanced chemical vapor deposition at 300 degrees C utilizing a SiH4/CH4/H2/Ar gas mixture. Low tensile stress film which is suitable as X-ray membrane can be achieved by annealing after silicon carbide film deposition. The microwave power over 800 watts and the gas ratio (Methane:Silane) larger than 1.5 are needed for the stoichiometry of SiC film. On the other hand, we deposited silicon-rich silicon nitride film on silicon substrate by low pressure chemical vapor deposition at 850 degrees C to 900 degrees C. In order to get low tensile stress film, different gas flow ratios (Dichlorosilane:Ammonia) were tested. The increased gas flow ratio (Dichlorosilane:Ammonia) and the increased deposition temperature are related to the decrease of tensile stress of film. Roughness, uniformity, optical transmittance and soft X-ray transmission of both films are reported. The absorption bands of both films were measured by FTIR spectroscopy. The surface morphology was monitored by AFM. The photon transmission of both films was measured in the range of 400 to 800 nm for visible light and 800 to 1600 ev photon energy for SR soft X-ray transmission was conducted at the Synchrotron Radiation Research Center, Hsinchu, Taiwan. The deposition rate of both films are 13 nm/min and 40 nm/min for silicon nitride and silicon carbide, respectively.

EUV mask pilot line at Intel Corporation

NASA Astrophysics Data System (ADS)

Stivers, Alan R.; Yan, Pei-Yang; Zhang, Guojing; Liang, Ted; Shu, Emily Y.; Tejnil, Edita; Lieberman, Barry; Nagpal, Rajesh; Hsia, Kangmin; Penn, Michael; Lo, Fu-Chang

2004-12-01

The introduction of extreme ultraviolet (EUV) lithography into high volume manufacturing requires the development of a new mask technology. In support of this, Intel Corporation has established a pilot line devoted to encountering and eliminating barriers to manufacturability of EUV masks. It concentrates on EUV-specific process modules and makes use of the captive standard photomask fabrication capability of Intel Corporation. The goal of the pilot line is to accelerate EUV mask development to intersect the 32nm technology node. This requires EUV mask technology to be comparable to standard photomask technology by the beginning of the silicon wafer process development phase for that technology node. The pilot line embodies Intel's strategy to lead EUV mask development in the areas of the mask patterning process, mask fabrication tools, the starting material (blanks) and the understanding of process interdependencies. The patterning process includes all steps from blank defect inspection through final pattern inspection and repair. We have specified and ordered the EUV-specific tools and most will be installed in 2004. We have worked with International Sematech and others to provide for the next generation of EUV-specific mask tools. Our process of record is run repeatedly to ensure its robustness. This primes the supply chain and collects information needed for blank improvement.

EUVL masks: paving the path for commercialization

NASA Astrophysics Data System (ADS)

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

2001-09-01

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

Diamond Coatings

NASA Technical Reports Server (NTRS)

1990-01-01

Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

Study on Buckling of Stiff Thin Films on Soft Substrates as Functional Materials

NASA Astrophysics Data System (ADS)

Ma, Teng

In engineering, buckling is mechanical instability of walls or columns under compression and usually is a problem that engineers try to prevent. In everyday life buckles (wrinkles) on different substrates are ubiquitous -- from human skin to a rotten apple they are a commonly observed phenomenon. It seems that buckles with macroscopic wavelengths are not technologically useful; over the past decade or so, however, thanks to the widespread availability of soft polymers and silicone materials micro-buckles with wavelengths in submicron to micron scale have received increasing attention because it is useful for generating well-ordered periodic microstructures spontaneously without conventional lithographic techniques. This thesis investigates the buckling behavior of thin stiff films on soft polymeric substrates and explores a variety of applications, ranging from optical gratings, optical masks, energy harvest to energy storage. A laser scanning technique is proposed to detect micro-strain induced by thermomechanical loads and a periodic buckling microstructure is employed as a diffraction grating with broad wavelength tunability, which is spontaneously generated from a metallic thin film on polymer substrates. A mechanical strategy is also presented for quantitatively buckling nanoribbons of piezoelectric material on polymer substrates involving the combined use of lithographically patterning surface adhesion sites and transfer printing technique. The precisely engineered buckling configurations provide a route to energy harvesters with extremely high levels of stretchability. This stiff-thin-film/polymer hybrid structure is further employed into electrochemical field to circumvent the electrochemically-driven stress issue in silicon-anode-based lithium ion batteries. It shows that the initial flat silicon-nanoribbon-anode on a polymer substrate tends to buckle to mitigate the lithiation-induced stress so as to avoid the pulverization of silicon anode. Spontaneously generated submicron buckles of film/polymer are also used as an optical mask to produce submicron periodic patterns with large filling ratio in contrast to generating only ˜100 nm edge submicron patterns in conventional near-field soft contact photolithography. This thesis aims to deepen understanding of buckling behavior of thin films on compliant substrates and, in turn, to harness the fundamental properties of such instability for diverse applications.

Patterned Growth of Carbon Nanotubes or Nanofibers

NASA Technical Reports Server (NTRS)

Delzeit, Lance D.

2004-01-01

A method and apparatus for the growth of carbon nanotubes or nanofibers in a desired pattern has been invented. The essence of the method is to grow the nanotubes or nanofibers by chemical vapor deposition (CVD) onto a patterned catalyst supported by a substrate. The figure schematically depicts salient aspects of the method and apparatus in a typical application. A substrate is placed in a chamber that contains both ion-beam sputtering and CVD equipment. The substrate can be made of any of a variety of materials that include several forms of silicon or carbon, and selected polymers, metals, ceramics, and even some natural minerals and similar materials. Optionally, the substrate is first coated with a noncatalytic metal layer (which could be a single layer or could comprise multiple different sublayers) by ion-beam sputtering. The choice of metal(s) and thickness(es) of the first layer (if any) and its sublayers (if any) depends on the chemical and electrical properties required for subsequent deposition of the catalyst and the subsequent CVD of the carbon nanotubes. A typical first-sublayer metal is Pt, Pd, Cr, Mo, Ti, W, or an alloy of two or more of these elements. A typical metal for the second sublayer or for an undivided first layer is Al at a thickness .1 nm or Ir at a thickness .5 nm. Proper choice of the metal for a second sublayer of a first layer makes it possible to use a catalyst that is chemically incompatible with the substrate. In the next step, a mask having holes in the desired pattern is placed over the coated substrate. The catalyst is then deposited on the coated substrate by ion-beam sputtering through the mask. Optionally, the catalyst could be deposited by a technique other than sputtering and/or patterned by use of photolithography, electron- beam lithography, or another suitable technique. The catalytic metal can be Fe, Co, Ni, or an alloy of two or more of these elements, deposited to a typical thickness in the range from 0.1 to 20 nm.

III-V compound semiconductor material characterization of microstructures and nanostructures on various optoelectronic devices with analytical transmission electron microscopy and high resolution electron microscopy

NASA Astrophysics Data System (ADS)

Zhou, Wei

Analytical Transmission Electron Microscopy (TEM) and High Resolution Electron Microscopy have been carried out to characterize microstructures and nanostructures in various III-V compound semiconductor devices by metalorganic chemical vapor deposition (MOCVD). The low-defect GaN nonplanar templates by lateral epitaxial overgrowth (LEO) has a trapezoidal cross-section with smooth (0001) and {112¯2} facets. Penetration of threading dislocations (TDs) beyond mask windows is observed in ordinary LEO substrates. In two-step LEO substrates, where TDs are engineered to bend 90° in the TD bending layer after the first LEO step, only perfect a-type dislocations with Burgers vector b = 1/3 <112¯0> are generated in the upper Post-bending layer with a density of ˜8 x 107cm-2. The demonstrated 3-dimensional dislocation spatial distribution in the LEO nonplanar substrate substantiates the dislocation reaction mechanism. Al0.07GaN/GaN superlattice can further decrease dislocations. InGaN QW thickness enhancement on top of GaN nonplanar templates has been verified to influence the optoelectronic properties significantly. Dense arrays of hexagonally ordered MOCVD-grown (In)(Ga)As nano-QDs by block copolymer nanolithography & selective area growth (SAG), approximately 20nm in diameter and 40nm apart with a density of 1011/cm 2, are perfect crystals by TEM. V-shaped defects and worse InAs growth uniformity have been observed in multiple layers of vertically coupled self-assembled InAs nanostructure arrays on strain-modulated GaAs substrates. TEM shows a smooth coalesced GaN surface with a thickness as thin as ˜200nm after Nano-LEO and a defect reduction of 70%-75%. The (In)GaAs 20 nm twist bonded compliant substrates have almost no compliant effect and higher dislocation density, but the 10nm compliant substrates are on the contrary. A 60nm oxygen-infiltrated crystallized transition layer is observed between the amorphous oxidized layer and the crystallized unoxidized aperture in Al xGa1-xAs wet lateral oxidation, potentially influencing the current confinement characteristic of the sub-micron oxide aperture. Almost no dislocation is aroused by the wet lateral oxidation of In0.52Al 0.48As in the InP microresonator waveguides. XTEM was performed to compare InP SAG regions with 10˜50mum masks, which shows the performance deterioration of laser threshold current densities in the case of 50mum mask results from high density of dislocations induced from the highly strained QW structures caused by the high enhancements.

Photodeposition Method For Fabricating A Three-Dimensional, Patterned Polymer Microstructure

DOEpatents

Walt, David R.; Healey, Brian G.

2001-03-13

The present invention is a photodeposition methodology for fabricating a three-dimensional patterned polymer microstructure. A variety of polymeric structures can be fabricated on solid substrates using unitary fiber optic arrays for light delivery. The methodology allows micrometer-scale photopatterning for the fabricated structures using masks substantially larger than the desired dimensions of the microstructure.

Effects of Palagonitic Dust Coatings on Thermal Emission Spectra of Rocks and Minerals: Implications for Mineralogical Characterization of the Martian Surface by MGS-TES

NASA Technical Reports Server (NTRS)

Graff, T. G.; Morris, R.; Christensen, P.

2001-01-01

Thermal emission measurements on dust-coated rocks and minerals show that a 300 5m thick layer is required to mask emission from the substrate and that non-linear effects are present. Additional information is contained in the original extended abstract.

Superconducting microcircuitry by the microlithographic patterning of superconducting compounds and related materials

DOEpatents

Coppa, N.V.

1993-08-24

A method is described of producing superconducting microcircuits comprising the steps of: depositing a thin film of Ba[sub 2]Cu[sub 3]O[sub 5+x](O < x < 1) onto a substrate; depositing a thin film of a dopant onto said thin film of Ba[sub 2]Cu[sub 3]O[sub 5+x]; depositing a photoresist onto said thin film of a dopant; shining light through a mask containing a pattern for a desired circuit configuration and onto said photoresist; developing said photoresist to remove portions of said photoresist shined by the light and to selectively expose said dopant film; etching said selectively exposed dopant film from said thin film of Ba[sub 2]Cu[sub 3]O[sub 5+x] to form a pattern of dopant; and heating said substrate at a temperature and for a period of time sufficient to diffuse and react said pattern of dopant with said thin film of Ba[sub 2]Cu[sub 3]O[sub 5+x].

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 made but a continued collaborative effort will be needed along with timely infrastructure investments to meet these challenging goals.

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

NASA Astrophysics Data System (ADS)

Shoji, Masahiro; Inoue, Tadao; Yamabe, Masaki

2010-05-01

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

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

NASA Astrophysics Data System (ADS)

Hisamura, Toshiyuki; Wu, Xin

2009-10-01

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

Mask replication using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

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

2011-11-01

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

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

NASA Astrophysics Data System (ADS)

Hector, Scott

2005-11-01

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

RF performances of inductors integrated on localized p+-type porous silicon regions

PubMed Central

2012-01-01

To study the influence of localized porous silicon regions on radiofrequency performances of passive devices, inductors were integrated on localized porous silicon regions, full porous silicon sheet, bulk silicon and glass substrates. In this work, a novel strong, resistant fluoropolymer mask is introduced to localize the porous silicon on the silicon wafer. Then, the quality factors and resonant frequencies obtained with the different substrates are presented. A first comparison is done between the performances of inductors integrated on same-thickness localized and full porous silicon sheet layers. The effect of the silicon regions in the decrease of performances of localized porous silicon is discussed. Then, the study shows that the localized porous silicon substrate significantly reduces losses in comparison with high-resistivity silicon or highly doped silicon bulks. These results are promising for the integration of both passive and active devices on the same silicon/porous silicon hybrid substrate. PMID:23009746

Soft liquid phase adsorption for fabrication of organic semiconductor films on wettability patterned surfaces.

PubMed

Watanabe, Satoshi; Akiyoshi, Yuri; Matsumoto, Mutsuyoshi

2014-01-01

We report a soft liquid-phase adsorption (SLPA) technique for the fabrication of organic semiconductor films on wettability-patterned substrates using toluene/water emulsions. Wettability-patterned substrates were obtained by the UV-ozone treatment of self-assembled monolayers of silane coupling agents on glass plates using a metal mask. Organic semiconductor polymer films were formed selectively on the hydrophobic part of the wettability-patterned substrates. The thickness of the films fabricated by the SLPA technique is significantly larger than that of the films fabricated by dip-coating and spin-coating techniques. The film thickness can be controlled by adjusting the volume ratio of toluene to water, immersion angle, immersion temperature, and immersion time. The SLPA technique allows for the direct production of organic semiconductor films on wettability-patterned substrates with minimized material consumption and reduced number of fabrication steps.

Development of movable mask system to cope with high beam current

NASA Astrophysics Data System (ADS)

Suetsugu, Y.; Shibata, K.; Sanami, T.; Kageyama, T.; Takeuchi, Y.

2003-07-01

The KEK B factory (KEKB), a high current electron-positron collider, has a movable mask (or collimator) system to reduce the background noise in the BELLE detector coming from spent particles. The early movable masks, however, had severe problems of heating, arcing, and vacuum leaks over the stored beam current of several hundred mA. The cause is intense trapped higher order modes (HOMs) excited at the mask head, where the cross section of the beam chamber changed drastically. The mask head, made of copper-tungsten alloy or pure copper, was frequently damaged by hitting of the high energy beam at the same time. Since the problems of the mask were revealed, several kinds of improved masks have been designed employing rf technologies in dealing with the HOM and installed to the ring step by step. Much progress has come from adopting a trapped-mode free structure, where the mask was a bent chamber itself. Recently the further improved mask with a reduced HOM design or HOM dampers was developed to suppress the heating of vacuum components near the mask due to the HOM traveling from the mask. To avoid damage to the mask head, on the other hand, a titanium mask head was tried. The latest masks are working as expected now at the stored beam current of 1.5 A. Presented are the problems and experiences on the movable mask system for the KEKB, which are characteristic of and common in a high intensity accelerator.

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.

Design of aerosol face masks for children using computerized 3D face analysis.

PubMed

Amirav, Israel; Luder, Anthony S; Halamish, Asaf; Raviv, Dan; Kimmel, Ron; Waisman, Dan; Newhouse, Michael T

2014-08-01

Aerosol masks were originally developed for adults and downsized for children. Overall fit to minimize dead space and a tight seal are problematic, because children's faces undergo rapid and marked topographic and internal anthropometric changes in their first few months/years of life. Facial three-dimensional (3D) anthropometric data were used to design an optimized pediatric mask. Children's faces (n=271, aged 1 month to 4 years) were scanned with 3D technology. Data for the distance from the bridge of the nose to the tip of the chin (H) and the width of the mouth opening (W) were used to categorize the scans into "small," "medium," and "large" "clusters." "Average" masks were developed from each cluster to provide an optimal seal with minimal dead space. The resulting computerized contour, W and H, were used to develop the SootherMask® that enables children, "suckling" on their own pacifier, to keep the mask on their face, mainly by means of subatmospheric pressure. The relatively wide and flexible rim of the mask accommodates variations in facial size within and between clusters. Unique pediatric face masks were developed based on anthropometric data obtained through computerized 3D face analysis. These masks follow facial contours and gently seal to the child's face, and thus may minimize aerosol leakage and dead space.

The future of 2D metrology for display manufacturing

NASA Astrophysics Data System (ADS)

Sandstrom, Tor; Wahlsten, Mikael; Park, Youngjin

2016-10-01

The race to 800 PPI and higher in mobile devices and the transition to OLED displays are driving a dramatic development of mask quality: resolution, CDU, registration, and complexity. 2D metrology for large area masks is necessary and must follow the roadmap. Driving forces in the market place point to continued development of even more dense displays. State-of-the-art metrology has proven itself capable of overlay below 40 nm and registration below 65 nm for G6 masks. Future developments include incoming and recurrent measurements of pellicalized masks at the panel maker's factory site. Standardization of coordinate systems across supplier networks is feasible. This will enable better yield and production economy for both mask and panel maker. Better distortion correction methods will give better registration on the panels and relax the flatness requirements of the mask blanks. If panels are measured together with masks and the results are used to characterize the aligners, further quality and yield improvements are possible. Possible future developments include in-cell metrology and integration with other instruments in the same platform.

Fabrication of 2-inch nano patterned sapphire substrate with high uniformity by two-beam laser interference lithography

NASA Astrophysics Data System (ADS)

Dai, LongGui; Yang, Fan; Yue, Gen; Jiang, Yang; Jia, Haiqiang; Wang, Wenxin; Chen, Hong

2014-11-01

Generally, nano-scale patterned sapphire substrate (NPSS) has better performance than micro-scale patterned sapphire substrate (MPSS) in improving the light extraction efficiency of LEDs. Laser interference lithography (LIL) is one of the powerful fabrication methods for periodic nanostructures without photo-masks for different designs. However, Lloyd's mirror LIL system has the disadvantage that fabricated patterns are inevitably distorted, especially for large-area twodimensional (2D) periodic nanostructures. Herein, we introduce two-beam LIL system to fabricate consistent large-area NPSS. Quantitative analysis and characterization indicate that the high uniformity of the photoresist arrays is achieved. Through the combination of dry etching and wet etching techniques, the well-defined NPSS with period of 460 nm were prepared on the whole sapphire substrate. The deviation is 4.34% for the bottom width of the triangle truncated pyramid arrays on the whole 2-inch sapphire substrate, which is suitable for the application in industrial production of NPSS.

A high-coverage nanoparticle monolayer for the fabrication of a subwavelength structure on InP substrates.

PubMed

Kim, Dae-Seon; Park, Min-Su; Jang, Jae-Hyung

2011-08-01

Subwavelength structures (SWSs) were fabricated on the Indium Phosphide (InP) substrate by utilizing the confined convective self-assembly (CCSA) method followed by reactive ion etching (RIE). The surface condition of the InP substrate was changed by depositing a 30-nm-thick SiO2 layer and subsequently treating the surface with O2 plasma to achieve better surface coverage. The surface coverage of nanoparticle monolayer reached 90% by using O2 plasma-treated SiO2/InP substrate among three kinds of starting substrates such as the bare InP, SiO2/InP and O2 plasma-treated SiO2/InP substrate. A nanoparticle monolayer consisting of polystyrene spheres with diameter of 300 nm was used as an etch mask for transferring a two-dimensional periodic pattern onto the InP substrate. The fabricated conical SWS with an aspect ratio of 1.25 on the O2 plasma-treated SiO2/InP substrate exhibited the lowest reflectance. The average reflectance of the conical SWS was 5.84% in a spectral range between 200 and 900 nm under the normal incident angle.

Method for extreme ultraviolet lithography

DOEpatents

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

1999-01-01

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

Low-Angle-Incidence Microchannel Epitaxy of a-Plane GaN Grown by Ammonia-Based Metal-Organic Molecular Beam Epitaxy

NASA Astrophysics Data System (ADS)

Lin, Chia-Hung; Uchiyama, Shota; Maruyama, Takahiro; Naritsuka, Shigeya

2012-04-01

Low-angle-incidence microchannel epitaxy (LAIMCE) of a-plane GaN was performed using ammonia-based metal-organic molecular beam epitaxy to obtain wide and thin lateral overgrowth over a SiO2 mask. Trimethylgallium (TMG) was supplied perpendicular to the openings cut in the mask with a low incident angle of 5° relative to the substrate plane. The [NH3]/[TMG] ratio (R) dependence of GaN LAIMCE was optimized by varying R from 5 to 30. A wide lateral overgrowth of 3.7 µm with a dislocation density below the transmission electron microscope detection limit was obtained at R=15 for a thickness of 520 nm.

Method for extreme ultraviolet lithography

DOEpatents

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

2000-01-01

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

Fabrication and Characterization of Vertically Aligned ZnO Nanorod Arrays via Inverted Monolayer Colloidal Crystals Mask

NASA Astrophysics Data System (ADS)

Chen, Cheng; Ding, Taotao; Qi, Zhiqiang; Zhang, Wei; Zhang, Jun; Xu, Juan; Chen, Jingwen; Dai, Jiangnan; Chen, Changqing

2018-04-01

The periodically ordered ZnO nanorod (NR) arrays have been successfully synthesized via a hydrothermal approach on the silicon substrates by templating of the TiO2 ring deriving from the polystyrene (PS) nanosphere monolayer colloidal crystals (MCC). With the inverted MCC mask, sol-gel-derived ZnO seeds could serve as the periodic nucleation positions for the site-specific growth of ZnO NRs. The large-scale patterned arrays of single ZnO NR with good side-orientation can be readily produced. According to the experimental results, the as-integrated ZnO NR arrays showed an excellent crystal quality and optical property, very suitable for optoelectronic applications such as stimulated emitters and ZnO photonic crystal devices.

A simple approach to patterned protein immobilization on silicon via electrografting from diazonium salt solutions.

PubMed

Flavel, Benjamin S; Gross, Andrew J; Garrett, David J; Nock, Volker; Downard, Alison J

2010-04-01

A highly versatile method utilizing diazonium salt chemistry has been developed for the fabrication of protein arrays. Conventional ultraviolet mask lithography was used to pattern micrometer sized regions into a commercial photoresist on a highly doped p-type silicon (100) substrate. These patterned regions were used as a template for the electrochemical grafting of the in situ generated p-aminobenzenediazonium cation to form patterns of aminophenyl film on silicon. Immobilization of biomolecules was demonstrated by coupling biotin to the aminophenyl regions followed by reaction with fluorescently labeled avidin and visualization with fluorescence microscopy. This simple patterning strategy is promising for future application in biosensor devices.

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Nanostructure Secondary-Mirror Apodizing Mask for Transmitter Signal Suppression in a Duplex Telescope

NASA Technical Reports Server (NTRS)

Hagopian, John; Livas, Jeffrey; Shiri, Shahram; Getty, Stephanie; Tveekrem, June; Butler, James

2012-01-01

A document discusses a nanostructure apodizing mask, made of multi-walled carbon nanotubes, that is applied to the centers (or in and around the holes) of the secondary mirrors of telescopes that are used to interferometrically measure the strain of space-time in response to gravitational waves. The shape of this ultra-black mask can be adjusted to provide a smooth transition to the clear aperture of the secondary mirror to minimize diffracted light. Carbon nanotubes grown on silicon are a viable telescope mirror substrate, and can absorb significantly more light than other black treatments. The hemispherical reflectance of multi-walled carbon nanotubes grown at GSFC is approximately 3 to 10 times better than a standard aerospace paint used for stray light control. At the LISA (Laser Interferometer Space Antenna) wavelength of 1 micron, the advantage over paint is a factor of 10. Primarily, in the center of the secondary mirror (in the region of central obscuration, where no received light is lost) a black mask is applied to absorb transmitted light that could be reflected back into the receiver. In the LISA telescope, this is in the center couple of millimeters. The shape of this absorber is critical to suppress diffraction at the edge. By using the correct shape, the stray light can be reduced by approximately 10 to the 9 orders of magnitude versus no center mask. The effect of the nanotubes has been simulated in a stray-light model. The effect of the apodizing mask has been simulated in a near-field diffraction model. Specifications are geometry-dependent, but the baseline design for the LISA telescope has been modeled as well. The coatings are somewhat fragile, but work is continuing to enhance adhesion.

Neural Correlates and Mechanisms of Spatial Release From Masking: Single-Unit and Population Responses in the Inferior Colliculus

PubMed Central

Lane, Courtney C.; Delgutte, Bertrand

2007-01-01

Spatial release from masking (SRM), a factor in listening in noisy environments, is the improvement in auditory signal detection obtained when a signal is separated in space from a masker. To study the neural mechanisms of SRM, we recorded from single units in the inferior colliculus (IC) of barbiturate-anesthetized cats, focusing on low-frequency neurons sensitive to interaural time differences. The stimulus was a broadband chirp train with a 40-Hz repetition rate in continuous broadband noise, and the unit responses were measured for several signal and masker (virtual) locations. Masked thresholds (the lowest signal-to-noise ratio, SNR, for which the signal could be detected for 75% of the stimulus presentations) changed systematically with signal and masker location. Single-unit thresholds did not necessarily improve with signal and masker separation; instead, they tended to reflect the units’ azimuth preference. Both how the signal was detected (through a rate increase or decrease) and how the noise masked the signal response (suppressive or excitatory masking) changed with signal and masker azimuth, consistent with a cross-correlator model of binaural processing. However, additional processing, perhaps related to the signal’s amplitude modulation rate, appeared to influence the units’ responses. The population masked thresholds (the most sensitive unit’s threshold at each signal and masker location) did improve with signal and masker separation as a result of the variety of azimuth preferences in our unit sample. The population thresholds were similar to human behavioral thresholds in both SNR value and shape, indicating that these units may provide a neural substrate for low-frequency SRM. PMID:15857966

A conceptual approach to the masking effect of measures of disproportionality.

PubMed

Maignen, Francois; Hauben, Manfred; Hung, Eric; Holle, Lionel Van; Dogne, Jean-Michel

2014-02-01

Masking is a statistical issue by which true signals of disproportionate reporting are hidden by the presence of other products in the database. Masking is currently not perfectly understood. There is no algorithm to identify the potential masking drugs to remove them for subsequent analyses of disproportionality. The primary objective of our study is to develop a mathematical framework for assessing the extent and impact of the masking effect of measures of disproportionality. We have developed a masking ratio that quantifies the masking effect of a given product. We have conducted a simulation study to validate our algorithm. The masking ratio is a measure of the strength of the masking effect whether the analysis is performed at the report or event level, and the manner in which reports are allocated to cells in the contingency table significantly impact the masking mechanisms. The reports containing both the product of interest and the masking product need to be handled appropriately. The proposed algorithm can use simplified masking provided that underlying assumptions (in particular the size of the database) are verified. For any event, the strongest masking effect is associated with the drug with the highest number of records (reports excluding the product of interest). Our study provides significant insights with practical implications for real-world pharmacovigilance that are supported by both real and simulated data. The public health impact of masking is still unknown. Copyright © 2013 John Wiley & Sons, Ltd.

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

NASA Astrophysics Data System (ADS)

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

1999-07-01

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

Scent trailing by virgin females ofPseudococcm calceolariae.

PubMed

Rotundo, G; Tremblay, E

1981-01-01

Virgin females of the citrophilous mealybugPseudococcus calceolariae (Mask.) deposit scent marks as trails on the substrate on which they rest or move. These substances elicit attraction and sexual behavior by conspecific males. The same responses were obtained when males were bioassayed on extracts from filter paper disks on which females had rested. The significance of scent trailing in mealybugs is discussed.

Polarity-inverted lateral overgrowth and selective wet-etching and regrowth (PILOSWER) of GaN.

PubMed

Jang, Dongsoo; Jue, Miyeon; Kim, Donghoi; Kim, Hwa Seob; Lee, Hyunkyu; Kim, Chinkyo

2018-03-07

On an SiO 2 -patterned c-plane sapphire substrate, GaN domains were grown with their polarity controlled in accordance with the pattern. While N-polar GaN was grown on hexagonally arranged circular openings, Ga-polar GaN was laterally overgrown on mask regions due to polarity inversion occurring at the boundary of the circular openings. After etching of N-polar GaN on the circular openings by H 3 PO 4 , this template was coated with 40-nm Si by sputtering and was slightly etched by KOH. After slight etching, a thin layer of Si left on the circular openings of sapphire,but not on GaN, was oxidized during thermal annealing and served as a dielectric mask during subsequent regrowth. Thus, the subsequent growth of GaN was made only on the existing Ga-polar GaN domains, not on the circular openings of the sapphire substrate. Transmission electron microscopy analysis revealed no sign of threading dislocations in this film. This approach may help fabricating an unholed and merged GaN film physically attached to but epitaxially separated from the SiO 2 -patterned sapphire.

Orally disintegrating dosage forms and taste-masking technologies; 2010.

PubMed

Douroumis, Dennis

2011-05-01

In the last decade the development of orally disintegrating tablets (ODTs) and thin-film platforms has grown enormously in the field of pharmaceutical industry. A wide variety of new masking technologies combined with the aforementioned platforms have been developed in order to mask the taste of bitter active substances and achieve patient compliance. The commercial success and viability of such products requires the development of robust formulations with excellent palatability, disintegration times, physicochemical stability and pharmacokinetic profiles. In this review, emerging taste-masking technologies applied to solid dosage form manufacturing are summarized. The unique features and principles of taste-masking approaches used with ODT platforms are discussed, including the advantages and limitations of each technology. A brief discussion is also included on the taste masking of thin-film technologies, owing to their similar applications and requirements. This review elucidates the unique features of current commercially available or highly promising ODT and thin-film technologies, along with taste-masking approaches used in the manufacturing of oral solid dosage forms. A better understanding of these drug delivery approaches will help researchers to select the appropriate platform, or to develop innovative products with improved safety, compliance and clinical value.

Cicada-Wing-Inspired Self-Cleaning Antireflection Coatings on Polymer Substrates.

PubMed

Chen, Ying-Chu; Huang, Zhe-Sheng; Yang, Hongta

2015-11-18

The cicada has transparent wings with remarkable self-cleaning properties and high transmittance over the whole visible spectral range, which is derived from periodic conical structures covering the wing surface. Here we report a scalable self-assembly technique for fabricating multifunctional optical coatings that mimic cicada-wing structures. Spin-coated two-dimensional non-close-packed colloidal crystals are utilized as etching masks to pattern subwavelength-structured cone arrays directly on polymer substrates. The resulting gratings exhibit broadband antireflection performance and superhydrophobic properties after surface modification. The dependence of the cone shape and size on the antireflective and self-cleaning properties has also been investigated in this study.

Cantilever epitaxial process

DOEpatents

Ashby, Carol I.; Follstaedt, David M.; Mitchell, Christine C.; Han, Jung

2003-07-29

A process of growing a material on a substrate, particularly growing a Group II-VI or Group III-V material, by a vapor-phase growth technique where the growth process eliminates the need for utilization of a mask or removal of the substrate from the reactor at any time during the processing. A nucleation layer is first grown upon which a middle layer is grown to provide surfaces for subsequent lateral cantilever growth. The lateral growth rate is controlled by altering the reactor temperature, pressure, reactant concentrations or reactant flow rates. Semiconductor materials, such as GaN, can be produced with dislocation densities less than 10.sup.7 /cm.sup.2.

Graphoepitaxy integration and pattern transfer of lamellar silicon-containing high-chi block copolymers

NASA Astrophysics Data System (ADS)

Bézard, P.; Chevalier, X.; Legrain, A.; Navarro, C.; Nicolet, C.; Fleury, G.; Cayrefourcq, I.; Tiron, R.; Zelsmann, M.

2018-03-01

In this work, we present our recent achievements on the integration and transfer etching of a novel silicon-containing high-χ block copolymer for lines/spaces applications. Developed carbo-silane BCPs are synthesized under industrial conditions and present periodicities as low as 14 nm. A full directed self-assembly by graphoepitaxy process is shown using standard photolithography stacks and all processes are performed on 300 mm wafer compatible tools. Specific plasma processes are developed to isolate perpendicular lamellae and sub-12 nm features are finally transferred into silicon substrates. The quality of the final BCP hard mask (CDU, LWR, LER) are also investigated. Finally, thanks to the development of dedicated neutral layers and top-coats allowing perpendicular orientations, it was possible to investigate plasma etching experiments on full-sheets at 7 nm resolution, opening the way to the integration of these polymers in chemoepitaxy stacks.

Advanced mask cleaning for 0.20-μm technology: an integrated user-supplier approach

NASA Astrophysics Data System (ADS)

Poschenrieder, Rudolf; Hay, Bernd; Beier, Matthias; Hourd, Andrew C.; Stuemer, Harald; Gairing, Thomas M.

1998-12-01

A newly developed photomask final cleaning system, STEAG HamaTech's Advanced Single Substrate Cleaner, ASC 500, was assessed and optimized at the Siemens mask shop in Munich, Germany, under production conditions within the Esprit European Semiconductor Equipment Assessment programme (SEA). The project was carried out together with the active participation of Compugraphics Intl. Ltd. (UK), DuPont Photomasks, Inc. (Germany; Photronics-MZD, Germany). The results of the assessment are presented, focusing on the cleaning performance at the 0.25 micrometer defect level on photomasks, equipment reliability and Cost of Ownership data. A reticle free of soft defects on glass and on chrome down to the 0.25 micrometer level requires an excellent cleaning process and the use of high-end inspection tools like the KLA STARlight. In order to get a full understanding of the nature of the detected features additional investigations on the blank quality have been carried out. These investigations include the questions whether a detection is a hard or a soft defect and whether small defects on chrome are able to move on the reticle surface. Final cleaning recipes have been optimized in respect to cleaning efficiency while maintaining high throughput and low Cost of Ownership. A benchmark comparison against other final cleaning tools at the partner's maskshops showed the leading data of the ASC 500. It was found that a cleaning program which includes several substrate flips and a combination of the available cleaning methods acid- dispense, water pressure jet clean, brush and megasonic clean was best suitable to achieve these goals. In particular the use of the brush unit was shown to improve the yield while not adding damage to the plate.

Effect of SPM-based cleaning POR on EUV mask performance

NASA Astrophysics Data System (ADS)

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

2011-11-01

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

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.

A new predictive model for continuous positive airway pressure in the treatment of obstructive sleep apnea.

PubMed

Ebben, Matthew R; Narizhnaya, Mariya; Krieger, Ana C

2017-05-01

Numerous mathematical formulas have been developed to determine continuous positive airway pressure (CPAP) without an in-laboratory titration study. Recent studies have shown that style of CPAP mask can affect the optimal pressure requirement. However, none of the current models take mask style into account. Therefore, the goal of this study was to develop new predictive models of CPAP that take into account the style of mask interface. Data from 200 subjects with attended CPAP titrations during overnight polysomnograms using nasal masks and 132 subjects using oronasal masks were randomized and split into either a model development or validation group. Predictive models were then created in each model development group and the accuracy of the models was then tested in the model validation groups. The correlation between our new oronasal model and laboratory determined optimal CPAP was significant, r = 0.61, p < 0.001. Our nasal formula was also significantly related to laboratory determined optimal CPAP, r = 0.35, p < 0.001. The oronasal model created in our study significantly outperformed the original CPAP predictive model developed by Miljeteig and Hoffstein, z = 1.99, p < 0.05. The predictive performance of our new nasal model did not differ significantly from Miljeteig and Hoffstein's original model, z = -0.16, p < 0.90. The best predictors for the nasal mask group were AHI, lowest SaO2, and neck size, whereas the top predictors in the oronasal group were AHI and lowest SaO2. Our data show that predictive models of CPAP that take into account mask style can significantly improve the formula's accuracy. Most of the past models likely focused on model development with nasal masks (mask style used for model development was not typically reported in previous investigations) and are not well suited for patients using an oronasal interface. Our new oronasal CPAP prediction equation produced significantly improved performance compared to the well-known Miljeteig and Hoffstein formula in patients titrated on CPAP with an oronasal mask and was also significantly related to laboratory determined optimal CPAP.

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

NASA Astrophysics Data System (ADS)

Litt, Lloyd C.

2010-09-01

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

Suzuki-miyaura cross-coupling in acylation reactions, scope and recent developments.

PubMed

Blangetti, Marco; Rosso, Heléna; Prandi, Cristina; Deagostino, Annamaria; Venturello, Paolo

2013-01-17

Since the first report and due to its handiness and wide scope, the Suzuki-Miyaura (SM) cross coupling reaction has become a routine methodology in many laboratories worldwide. With respect to other common transition metal catalyzed cross couplings, the SM reaction has been so far less exploited as a tool to introduce an acyl function into a specific substrate. In this review, the various approaches found in the literature will be considered, starting from the direct SM acylative coupling to the recent developments of cross coupling between boronates and acyl chlorides or anhydrides. Special attention will be dedicated to the use of masked acyl boronates, alkoxy styryl and alkoxy dienyl boronates as coupling partners. A final section will be then focused on the acyl SM reaction as key synthetic step in the framework of natural products synthesis.

Methods and devices for fabricating three-dimensional nanoscale structures

DOEpatents

Rogers, John A.; Jeon, Seokwoo; Park, Jangung

2010-04-27

The present invention provides methods and devices for fabricating 3D structures and patterns of 3D structures on substrate surfaces, including symmetrical and asymmetrical patterns of 3D structures. Methods of the present invention provide a means of fabricating 3D structures having accurately selected physical dimensions, including lateral and vertical dimensions ranging from 10s of nanometers to 1000s of nanometers. In one aspect, methods are provided using a mask element comprising a conformable, elastomeric phase mask capable of establishing conformal contact with a radiation sensitive material undergoing photoprocessing. In another aspect, the temporal and/or spatial coherence of electromagnetic radiation using for photoprocessing is selected to fabricate complex structures having nanoscale features that do not extend entirely through the thickness of the structure fabricated.

Soft x-ray reduction camera for submicron lithography

DOEpatents

Hawryluk, Andrew M.; Seppala, Lynn G.

1991-01-01

Soft x-ray projection lithography can be performed using x-ray optical components and spherical imaging lenses (mirrors), which form an x-ray reduction camera. The x-ray reduction is capable of projecting a 5x demagnified image of a mask onto a resist coated wafer using 4.5 nm radiation. The diffraction limited resolution of this design is about 135 nm with a depth of field of about 2.8 microns and a field of view of 0.2 cm.sup.2. X-ray reflecting masks (patterned x-ray multilayer mirrors) which are fabricated on thick substrates and can be made relatively distortion free are used, with a laser produced plasma for the source. Higher resolution and/or larger areas are possible by varying the optic figures of the components and source characteristics.

EUV mask manufacturing readiness in the merchant mask industry

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Micropores and methods of making and using thereof

DOEpatents

Perroud, Thomas D.; Patel, Kamlesh D.; Meagher, Robert J.

2016-08-02

Disclosed herein are methods of making micropores of a desired height and/or width between two isotropic wet etched features in a substrate which comprises single-level isotropic wet etching the two features using an etchant and a mask distance that is less than 2.times. a set etch depth. Also disclosed herein are methods using the micropores and microfluidic devices comprising the micropores.

A Twice Electrochemical-Etching Method to Fabricate Superhydrophobic-Superhydrophilic Patterns for Biomimetic Fog Harvest.

PubMed

Yang, Xiaolong; Song, Jinlong; Liu, Junkai; Liu, Xin; Jin, Zhuji

2017-08-18

Superhydrophobic-superhydrophilic patterned surfaces have attracted more and more attention due to their great potential applications in the fog harvest process. In this work, we developed a simple and universal electrochemical-etching method to fabricate the superhydrophobic-superhydrophilic patterned surface on metal superhydrophobic substrates. The anti-electrochemical corrosion property of superhydrophobic substrates and the dependence of electrochemical etching potential on the wettability of the fabricated dimples were investigated on Al samples. Results showed that high etching potential was beneficial for efficiently producing a uniform superhydrophilic dimple. Fabrication of long-term superhydrophilic dimples on the Al superhydrophobic substrate was achieved by combining the masked electrochemical etching and boiling-water immersion methods. A long-term wedge-shaped superhydrophilic dimple array was fabricated on a superhydrophobic surface. The fog harvest test showed that the surface with a wedge-shaped pattern array had high water collection efficiency. Condensing water on the pattern was easy to converge and depart due to the internal Laplace pressure gradient of the liquid and the contact angle hysteresis contrast on the surface. The Furmidge equation was applied to explain the droplet departing mechanism and to control the departing volume. The fabrication technique and research of the fog harvest process may guide the design of new water collection devices.

Evaluation of taste-masking effects of pharmaceutical sweeteners with an electronic tongue system.

PubMed

Choi, Du Hyung; Kim, Nam Ah; Nam, Tack Soo; Lee, Sangkil; Jeong, Seong Hoon

2014-03-01

Electronic tongue systems have been developed for taste measurement of bitter drug substances in accurate taste comparison to development palatable oral formulations. This study was to evaluate the taste masking effect of conventional pharmaceutical sweeteners such as neohesperidin dihydrochalcone, sucrose, sucralose and aspartame. The model drugs were acetaminophen, ibuprofen, tramadol hydrochloride, and sildenafil citrate (all at 20 mM). The degree of bitterness was measured by a multichannel taste sensor system (an electronic tongue). The data was collected by seven sensors and analyzed by a statistical method of principal components analysis (PCA). The effect of taste masking excipient was dependent on the type of model drug. Changing the concentration of taste masking excipients affected the sensitivity of taste masking effect according to the type of drug. As the excipient concentration increased, the effect of taste masking increased. Moreover, most of the sensors showed a concentration-dependent pattern of the taste-masking agents as higher concentration provided higher selectivity. This might indicate that the sensors can detect small concentration changes of a chemical in solution. These results suggest that the taste masking could be evaluated based on the data of the electronic tongue system and that the formulation development process could be performed in a more efficient way.

Dark-field image contrast in transmission scanning electron microscopy: Effects of substrate thickness and detector collection angle.

PubMed

Woehl, Taylor; Keller, Robert

2016-12-01

An annular dark field (ADF) detector was placed beneath a specimen in a field emission scanning electron microscope operated at 30kV to calibrate detector response to incident beam current, and to create transmission images of gold nanoparticles on silicon nitride (SiN) substrates of various thicknesses. Based on the linear response of the ADF detector diodes to beam current, we developed a method that allowed for direct determination of the percentage of that beam current forward scattered to the ADF detector from the sample, i.e. the transmitted electron (TE) yield. Collection angles for the ADF detector region were defined using a masking aperture above the detector and were systematically varied by changing the sample to detector distance. We found the contrast of the nanoparticles, relative to the SiN substrate, decreased monotonically with decreasing inner exclusion angle and increasing substrate thickness. We also performed Monte Carlo electron scattering simulations, which showed quantitative agreement with experimental contrast associated with the nanoparticles. Together, the experiments and Monte Carlo simulations revealed that the decrease in contrast with decreasing inner exclusion angle was due to a rapid increase in the TE yield of the low atomic number substrate. Nanoparticles imaged at low inner exclusion angles (<150mrad) and on thick substrates (>50nm) showed low image contrast in their centers surrounded by a bright high-contrast halo on their edges. This complex image contrast was predicted by Monte Carlo simulations, which we interpreted in terms of mixing of the nominally bright field (BF) and ADF electron signals. Our systematic investigation of inner exclusion angle and substrate thickness effects on ADF t-SEM imaging provides fundamental understanding of the contrast mechanisms for image formation, which in turn suggest practical limitations and optimal imaging conditions for different substrate thicknesses. Copyright © 2016. Published by Elsevier B.V.

EUV mask defect inspection and defect review strategies for EUV pilot line and high volume manufacturing

NASA Astrophysics Data System (ADS)

Chan, Y. David; Rastegar, Abbas; Yun, Henry; Putna, E. Steve; Wurm, Stefan

2010-04-01

Reducing mask blank and patterned mask defects is the number one challenge for extreme ultraviolet lithography. If the industry succeeds in reducing mask blank defects at the required rate of 10X every year for the next 2-3 years to meet high volume manufacturing defect requirements, new inspection and review tool capabilities will soon be needed to support this goal. This paper outlines the defect inspection and review tool technical requirements and suggests development plans to achieve pilot line readiness in 2011/12 and high volume manufacturing readiness in 2013. The technical specifications, tooling scenarios, and development plans were produced by a SEMATECH-led technical working group with broad industry participation from material suppliers, tool suppliers, mask houses, integrated device manufacturers, and consortia. The paper summarizes this technical working group's assessment of existing blank and mask inspection/review infrastructure capabilities to support pilot line introduction and outlines infrastructure development requirements and tooling strategies to support high volume manufacturing.

Metacontrast masking is processed before grapheme-color synesthesia.

PubMed

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

2013-01-01

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

Developing a New Quantitative Account of Backward Masking

ERIC Educational Resources Information Center

Francis, Gregory

2003-01-01

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

Rapid colorimetric sensing platform for the detection of Listeria monocytogenes foodborne pathogen.

PubMed

Alhogail, Sahar; Suaifan, Ghadeer A R Y; Zourob, Mohammed

2016-12-15

Listeria monocytogenes is a serious cause of human foodborne infections worldwide, which needs spending billions of dollars for inspection of bacterial contamination in food every year. Therefore, there is an urgent need for rapid, in-field and cost effective detection techniques. In this study, rapid, low-cost and simple colorimetric assay was developed using magnetic nanoparticles for the detection of listeria bacteria. The protease from the listeria bacteria was detected using D-amino acid substrate. D-amino acid substrate was linked to the carboxylic acid on the magnetic nanoparticles using EDC/NHS chemistry. The cysteine residue at the C-terminal of the substrate was used for the self-assembled monolayer formation on the gold sensor surface, which in turn the black magnetic nanobeads will mask the golden color. The color will change from black to golden color upon the cleavage of the specific peptide sequence by the Listeria protease. The sensor was tested with serial dilutions of Listeria bacteria. It was found that the appearance of the gold surface area is proportional to the bacterial concentrations in CFU/ml. The lowest detection limit of the developed sensor for Listeria was found to be 2.17×10(2) colony forming unit/ml (CFU/ml). The specificity of the biosensor was tested against four different foodborne associated bacteria (Escherichia coli, Salmonella, Shigella flexnerii and Staphylococcus aureus). Finally, the sensor was tested with artificially spiked whole milk and ground meat spiked with listeria. Copyright © 2016 Elsevier B.V. All rights reserved.

The involvement of beta-1,4-Galactosyltransferase and N-Acetylglucosamine residues in fertilization has been lost in the horse.

PubMed

Mugnier, Sylvie; Boittin, Stéphane; Douet, Cécile; Monget, Philippe; Magistrini, Michèle; Goudet, Ghylène

2008-11-14

In human and rodents, sperm-zona pellucida binding is mediated by a sperm surface Galactosyltransferase that recognizes N-Acetylglucosamine residues on a glycoprotein ZPC. In large domestic mammals, the role of these molecules remains unclear: in bovine, they are involved in sperm-zona pellucida binding, whereas in porcine, they are not necessary. Our aim was to clarify the role of Galactosyltransferase and N-Acetylglucosamine residues in sperm-zona pellucida binding in ungulates. For this purpose, we analyzed the mechanism of sperm-zona pellucida interaction in a third ungulate: the horse, since the Galactosyltransferase and N-Acetylglucosamine residues have been localized on equine gametes. We masked the Galactosyltransferase and N-Acetylglucosamine residues before the co-incubation of gametes. Galactosyltransferase was masked either with an anti-Galactosyltransferase antibody or with the enzyme substrate, UDP Galactose. N-Acetylglucosamine residues were masked either with a purified Galactosyltransferase or with an anti-ZPC antibody. The number of spermatozoa bound to the zona pellucida did not decrease after the masking of Galactosyltransferase or N-Acetylglucosamine. So, these two molecules may not be necessary in the mechanism of in vitro sperm-zona pellucida interaction in the horse. The involvement of Galactosyltransferase and N-Acetylglucosamine residues in sperm-zona pellucida binding may have been lost during evolution in some ungulates, such as porcine and equine species.

Microlens array processor with programmable weight mask and direct optical input

NASA Astrophysics Data System (ADS)

Schmid, Volker R.; Lueder, Ernst H.; Bader, Gerhard; Maier, Gert; Siegordner, Jochen

1999-03-01

We present an optical feature extraction system with a microlens array processor. The system is suitable for online implementation of a variety of transforms such as the Walsh transform and DCT. Operating with incoherent light, our processor accepts direct optical input. Employing a sandwich- like architecture, we obtain a very compact design of the optical system. The key elements of the microlens array processor are a square array of 15 X 15 spherical microlenses on acrylic substrate and a spatial light modulator as transmissive mask. The light distribution behind the mask is imaged onto the pixels of a customized a-Si image sensor with adjustable gain. We obtain one output sample for each microlens image and its corresponding weight mask area as summation of the transmitted intensity within one sensor pixel. The resulting architecture is very compact and robust like a conventional camera lens while incorporating a high degree of parallelism. We successfully demonstrate a Walsh transform into the spatial frequency domain as well as the implementation of a discrete cosine transform with digitized gray values. We provide results showing the transformation performance for both synthetic image patterns and images of natural texture samples. The extracted frequency features are suitable for neural classification of the input image. Other transforms and correlations can be implemented in real-time allowing adaptive optical signal processing.

Programmable CGH on photochromic material using DMD generated masks

NASA Astrophysics Data System (ADS)

Alata, Romain; Zamkotsian, Frédéric; Lanzoni, Patrick; Pariani, Giorgio; Bianco, Andrea; Bertarelli, Chiara

2018-02-01

Computer Generated Holograms (CGHs) are used for wavefront shaping and complex optics testing, including aspherical and free-form optics. Today, CGHs are recorded directly with a laser or intermediate masks, allowing only the realization of binary CGHs; they are efficient but can reconstruct only pixilated images. We propose a Digital Micromirror Device (DMD) as a reconfigurable mask, to record rewritable binary and grayscale CGHs on a photochromic plate. The DMD is composed of 2048x1080 individually controllable micro-mirrors, with a pitch of 13.68 μm. This is a real-time reconfigurable mask, perfect for recording CGHs. The photochromic plate is opaque at rest and becomes transparent when it is illuminated with visible light of suitable wavelength. We have successfully recorded the very first amplitude grayscale CGH, in equally spaced levels, so called stepped CGH. We recorded up to 1000x1000 pixels CGHs with a contrast greater than 50, using Fresnel as well as Fourier coding scheme. Fresnel's CGH are obtained by calculating the inverse Fresnel transform of the original image at a given focus, ranging from 50cm to 2m. The reconstruction of the recorded images with a 632.8nm He-Ne laser beam leads to images with a high fidelity in shape, intensity, size and location. These results reveal the high potential of this method for generating programmable/rewritable grayscale CGHs, which combine DMDs and photochromic substrates.

An improved land mask for the SSM/I grid

NASA Technical Reports Server (NTRS)

Martino, Michael G.; Cavalieri, Donald J.; Gloersen, Per; Zwally, H. Jay; Acker, James G. (Editor)

1995-01-01

This paper discusses the development of a new land/ocean/coastline mask for use with Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) data, and other types of data which are mapped to the polar stereographic SSM/I grid. Pre-existing land masks were found to disagree, to lack certain land features, and to disagree with land boundaries that are visible in high resolution sensor imagery, such as imagery from the Synthetic Aperture Radar (SAR) on the Earth Resources Satellite (ERS-1). The Digital Chart of the World (DCW) database was initially selected as a source of shoreline data for this effort. Techniques for developing a land mask from these shoreline data are discussed. The resulting land mask, although not perfect, is seen to exhibit significant improvement over previous land mask products.

Electrostatically screened, voltage-controlled electrostatic chuck

DOEpatents

Klebanoff, Leonard Elliott

2001-01-01

Employing an electrostatically screened, voltage-controlled electrostatic chuck particularly suited for holding wafers and masks in sub-atmospheric operations will significantly reduce the likelihood of contaminant deposition on the substrates. The electrostatic chuck includes (1) an insulator block having a outer perimeter and a planar surface adapted to support the substrate and comprising at least one electrode (typically a pair of electrodes that are embedded in the insulator block), (2) a source of voltage that is connected to the at least one electrode, (3) a support base to which the insulator block is attached, and (4) a primary electrostatic shield ring member that is positioned around the outer perimeter of the insulator block. The electrostatic chuck permits control of the voltage of the lithographic substrate; in addition, it provides electrostatic shielding of the stray electric fields issuing from the sides of the electrostatic chuck. The shielding effectively prevents electric fields from wrapping around to the upper or front surface of the substrate, thereby eliminating electrostatic particle deposition.

Tunable Nanoantennas for Surface Enhanced Infrared Absorption Spectroscopy by Colloidal Lithography and Post-Fabrication Etching

NASA Astrophysics Data System (ADS)

Chen, Kai; Duy Dao, Thang; Nagao, Tadaaki

2017-03-01

We fabricated large-area metallic (Al and Au) nanoantenna arrays on Si substrates using cost-effective colloidal lithography with different micrometer-sized polystyrene spheres. Variation of the sphere size leads to tunable plasmon resonances in the middle infrared (MIR) range. The enhanced near-fields allow us to detect the surface phonon polaritons in the natural SiO2 thin layers. We demonstrated further tuning capability of the resonances by employing dry etching of the Si substrates with the nanoantennas acting as the etching masks. The effective refractive index of the nanoantenna surroundings is efficiently decreased giving rise to blueshifts of the resonances. In addition, partial removal of the Si substrates elevates the nanoantennas from the high-refractive-index substrates making more enhanced near-fields accessible for molecular sensing applications as demonstrated here with surface-enhanced infrared absorption (SEIRA) spectroscopy for a thin polymer film. We also directly compared the plasmonic enhancement from the Al and Au nanoantenna arrays.

A Study on the Formation of 2-Dimensional Tungsten Disulfide Thin Films on Sapphire Substrate by Sputtering and High Temperature Rapid Thermal Processing.

PubMed

Nam, Hanyeob; Kim, Hong-Seok; Han, Jae-Hee; Kwon, Sang Jik; Cho, Eou Sik

2018-09-01

As direct formation of p-type two-dimensional transition metal dichalcogenides (TMDC) films on substrates, tungsten disulfide (WS2) thin films were deposited onto sapphire glass substrate through shadow mask patterns by radio-frequency (RF) sputtering at different sputtering powers ranging from 60 W to 150 W and annealed by rapid thermal processing (RTP) at various high temperatures ranging from 500 °C to 800 °C. Based on scanning electron microscope (SEM) images and Raman spectra, better surface roughness and mode dominant E12g and A1g peaks were found for WS2 thin films prepared at higher RF sputtering powers. It was also possible to obtain high mobilities and carrier densities for all WS2 thin films based on results of Hall measurements. Process conditions for these WS2 thin films on sapphire substrate were optimized to low RF sputtering power and high temperature annealing.

Flexible organic light-emitting diodes with enhanced light out-coupling efficiency fabricated on a double-sided nanotextured substrate.

PubMed

Luo, Yu; Wang, Chunhui; Wang, Li; Ding, Yucheng; Li, Long; Wei, Bin; Zhang, Jianhua

2014-07-09

High-efficiency organic light-emitting diodes (OLEDs) have generated tremendous research interest. One of the exciting possibilities of OLEDs is the use of flexible plastic substrates, which unfortunately have a mismatching refractive index compared with the conventional ITO anode and the air. To unlock the light loss on flexible plastic, we report a high-efficiency flexible OLED directly fabricated on a double-sided nanotextured polycarbonate substrate by thermal nanoimprint lithography. The template for the nanoimprint process is a replicate from a silica arrayed with nanopillars and fabricated by ICP etching through a SiO2 colloidal spheres mask. It has been shown that with the internal quasi-periodical scattering gratings the efficiency enhancement can reach 50% for a green light OLED, and with an external antireflection structure, the normal transmittance is increased from 89% to 94% for paraboloid-like pillars. The OLED directly fabricated on the double-sided nanotextured polycarbonate substrate has reached an enhancing factor of ∼2.8 for the current efficiency.

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

NASA Astrophysics Data System (ADS)

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

1999-06-01

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

Does technology acceleration equate to mask cost acceleration?

NASA Astrophysics Data System (ADS)

Trybula, Walter J.; Grenon, Brian J.

2003-06-01

The technology acceleration of the ITRS Roadmap has many implications on both the semiconductor sup-plier community and the manufacturers. INTERNATIONAL SEMATECH has revaluated the projected cost of advanced technology masks. Building on the methodology developed in 1996 for mask costs, this work provided a critical review of mask yields and factors relating to the manufacture of photolithography masks. The impact of the yields provided insight into the learning curve for leading edge mask manufac-turing. The projected mask set cost was surprising, and the ability to provide first and second year cost estimates provided additional information on technology introduction. From this information, the impact of technology acceleration can be added to the projected yields to evaluate the impact on mask costs.

Highly Sensitive, Uniform, and Reproducible Surface-Enhanced Raman Spectroscopy Substrate with Nanometer-Scale Quasi-periodic Nanostructures.

PubMed

Jin, Yuanhao; Wang, Yingcheng; Chen, Mo; Xiao, Xiaoyang; Zhang, Tianfu; Wang, Jiaping; Jiang, Kaili; Fan, Shoushan; Li, Qunqing

2017-09-20

We introduce a simple and cost-effective approach for fabrication of effective surface-enhanced Raman spectroscopy (SERS) substrates. It is shown that the as-fabricated substrates show excellent SERS effects in various probe molecules with high sensitivity, that is, picomolar level detection, and also good reliability. With a SERS enhancement factor beyond 10 8 and excellent reproducibility (deviation less than 5%) of signal intensity, the fabrication of the SERS substrate is realized on a four-inch wafer and proven to be effective in pesticide residue detection. The SERS substrate is realized first through the fabrication of quasi-periodic nanostructured silicon with dimension features in tens of nanometers using superaligned carbon nanotubes networks as an etching mask, after which a large amount of hot spots with nanometer gaps are formed through deposition of a gold film. With rigorous nanostructure design, the enhanced performance of electromagnetic field distribution for nanostructures is optimized. With the advantage of cost-effective large-area preparation, it is believed that the as-fabricated SERS substrate could be used in a wide variety of actual applications where detection of trace amounts is necessary.

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.

"Slit Mask Design for the Giant Magellan Telescope Multi-object Astronomical and Cosmological Spectrograph"

NASA Astrophysics Data System (ADS)

Williams, Darius; Marshall, Jennifer L.; Schmidt, Luke M.; Prochaska, Travis; DePoy, Darren L.

2018-01-01

The Giant Magellan Telescope Multi-object Astronomical and Cosmological Spectrograph (GMACS) is currently in development for the Giant Magellan Telescope (GMT). GMACS will employ slit masks with a usable diameter of approximately 0.450 m for the purpose of multi-slit spectroscopy. Of significant importance are the design constraints and parameters of the multi-object slit masks themselves as well as the means for mapping astronomical targets to physical mask locations. Analytical methods are utilized to quantify deformation effects on a potential slit mask due to thermal expansion and vignetting of target light cones. Finite element analysis (FEA) is utilized to simulate mask flexure in changing gravity vectors. The alpha version of the mask creation program for GMACS, GMACS Mask Simulator (GMS), a derivative of the OSMOS Mask Simulator (OMS), is introduced.

Rates of initial acceptance of PAP masks and outcomes of mask switching.

PubMed

Bachour, Adel; Vitikainen, Pirjo; Maasilta, Paula

2016-05-01

Recently, we noticed a considerable development in alleviating problems related to positive airway pressure (PAP) masks. In this study, we report on the initial PAP mask acceptance rates and the effects of mask switching on mask-related symptoms. We prospectively collected all cases of mask switching in our sleep unit for a period of 14 months. At the time of the study, we used ResMed™ CPAP devices and masks. Mask switching was defined as replacing a mask used for at least 1 day with another type of mask. Changing to a different size but keeping the same type of mask did not count as mask switching. Switching outcomes were considered failed if the initial problem persisted or reappeared during the year that followed switching. Our patient pool was 2768. We recorded 343 cases of mask switching among 267 patients. Of the 566 patients who began new PAP therapy, 108 (39 women) had switched masks, yielding an initial mask acceptance rate of 81 %. The reason for switching was poor-fit/uncomfortable mask in 39 %, leak-related in 30 %, outdated model in 25 %, and nasal stuffiness in 6 % of cases; mask switching resolved these problems in 61 %. Mask switching occurred significantly (p = 0.037) more often in women and in new PAP users. The odds ratio for abandoning PAP therapy within 1 year after mask switching was 7.2 times higher (interval 4.7-11.1) than not switching masks. The initial PAP mask acceptance rate was high. Patients who switched their masks are at greater risk for abandoning PAP therapy.

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

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Preparation and morphology, magnetic properties of yttrium iron garnet nanodot arrays on Gd3Ga5O12 substrate

NASA Astrophysics Data System (ADS)

Xu, Zhiwang; Zheng, Hui; Han, Mangui

2017-07-01

In this work, yttrium iron garnet nanodot array has been deposited on Gd3Ga5O12 substrate by pulsed laser deposition through an ultrathin alumina mask. The morphology and magnetic properties of YIG nanodot array have been investigated. Scanning electron microscopy displays the prepared nanodot array has a sharp distribution in diameter centered at 330 nm with standard deviation of 20 nm. X-ray diffraction θ-2θ and pole figure analysis show the yttrium iron garnet nanodot array has oriented growth. Moreover, typical hysteresis loops and ferromagnetic resonance spectra display larger coercivity and multi-resonance peaks which are ascribed to this unique structure.

Recrystallization of tubules from natural lotus (Nelumbo nucifera) wax on a Au(111) surface

PubMed Central

Wandelt, Klaus

2011-01-01

Summary We present here the first results on the self-assembly of tubules of natural wax from lotus leaves on a single crystal Au(111) surface. A comparison of the tubule growth on Au(111) to that on HOPG is discussed. Although the tubule formation on both Au(111) and HOPG takes place on an intermediate wax film which should mask the substrate properties, the tubule orientations differ. In contrast to a vertical tubule orientation on HOPG, the tubules lie flat on Au(111). Taking into account the physical properties of HOPG and Au(111), we put forward a hypothesis which can explain the different tubule orientations on both substrates. PMID:21977438

Reflective optical imaging system

DOEpatents

Shafer, David R.

2000-01-01

An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements are characterized in order from object to image as convex, concave, convex and concave mirrors. The optical system is particularly suited for step and scan lithography methods. The invention increases the slit dimensions associated with ringfield scanning optics, improves wafer throughput and allows higher semiconductor device density.

Reflective optical imaging method and circuit

DOEpatents

Shafer, David R.

2001-01-01

An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements are characterized in order from object to image as convex, concave, convex and concave mirrors. The optical system is particularly suited for step and scan lithography methods. The invention increases the slit dimensions associated with ringfield scanning optics, improves wafer throughput and allows higher semiconductor device density.

Fabrication and Characterization of Vertical Gallium Nitride Power Schottky Diodes on Bulk GaN Substrates FY2016

DTIC Science & Technology

2016-12-01

2000 rpm to give a resist thickness of approximately 2 µm. Following resist exposure, a soft bake was performed at 95 °C for 60 s on a hot plate. The...resist was then exposed to UV light for 4.2 s while in contact with the mask. To perform image reversal, the exposed resist was baked at 105 °C for

Noninvasive esthetic treatment for hypomaturation amelogenesis imperfecta: a case report.

PubMed

Nahsan, Flávia Pardo Salata; Silva, Luciana Mendonça da; Lima, Thiago Mendes de; Bertocco, Verônica Pereira de Lima; Chui, Fabíola Mendonça da Silva; Martins, Leandro de Moura

2016-01-01

Enamel alterations, such as amelogenesis imperfecta, can compromise the harmony of the smile and the patient's self-esteem and may cause tooth sensitivity. A simple and effective treatment approach uses the natural stratification of composite resins to mask deficient enamel formation and mimic the natural appearance of the substrate. The operative steps and principles for restorative success are described in this case report with 36-month follow-up.

Digital One-Disc-One-Compound Method for High-Throughput Discovery of Prostate Cancer - Targeting Ligands

DTIC Science & Technology

2015-10-01

shown in Fig. 1a, the prepolymer mixture was sandwiched between photo mask and glass slide. Microdiscs were fabricated on the glass substrate through...polymerization of the prepolymer mixture and the acrylated silane under UV exposure. To achieve the more stable microdiscs for peptide synthesis, the...composition of prepolymer mixture was changed to PEG (Polyethylene Glycol)-diacrylate, crosslinker, photo initiator, 2-aminoethylmethacrylate, water

In-plane InSb nanowires grown by selective area molecular beam epitaxy on semi-insulating substrate.

PubMed

Desplanque, L; Bucamp, A; Troadec, D; Patriarche, G; Wallart, X

2018-07-27

In-plane InSb nanostructures are grown on a semi-insulating GaAs substrate using an AlGaSb buffer layer covered with a patterned SiO 2 mask and selective area molecular beam epitaxy. The shape of these nanostructures is defined by the aperture in the silicon dioxide layer used as a selective mask thanks to the use of an atomic hydrogen flux during the growth. Transmission electron microscopy reveals that the mismatch accommodation between InSb and GaAs is obtained in two steps via the formation of an array of misfit dislocations both at the AlGaSb buffer layer/GaAs and at the InSb nanostructures/AlGaSb interfaces. Several micron long in-plane nanowires (NWs) can be achieved as well as more complex nanostructures such as branched NWs. The electrical properties of the material are investigated by the characterization of an InSb NW MOSFET down to 77 K. The resulting room temperature field effect mobility values are comparable with those reported on back-gated MOSFETs based on InSb NWs obtained by vapor liquid solid growth or electrodeposition. This growth method paves the way to the fabrication of complex InSb-based nanostructures.

Adaptive wettability-enhanced surfaces ordered on molded etched substrates using shrink film

NASA Astrophysics Data System (ADS)

Jayadev, Shreshta; Pegan, Jonathan; Dyer, David; McLane, Jolie; Lim, Jessica; Khine, Michelle

2013-01-01

Superhydrophobic surfaces in nature exhibit desirable properties including self-cleaning, bacterial resistance, and flight efficiency. However, creating such intricate multi-scale features with conventional fabrication approaches is difficult, expensive, and not scalable. By patterning photoresist on pre-stressed shrink-wrap film, which contracts by 95% in surface area when heated, such features over large areas can be obtained easily. Photoresist serves as a dry etch mask to create complex and high-aspect ratio microstructures in the film. Using a double-shrink process, we introduce adaptive wettability-enhanced surfaces ordered on molded etched (AWESOME) substrates. We first create a mask out of the children’s toy ‘Shrinky-Dinks’ by printing dots using a laserjet printer. Heating this thermoplastic sheet causes the printed dots to shrink to a fraction of their original size. We then lithographically transfer the inverse pattern onto photoresist-coated shrink-wrap polyolefin film. The film is then plasma etched. After shrinking, the film serves as a high-aspect ratio mold for polydimethylsiloxane, creating a superhydrophobic surface with water contact angles >150° and sliding angles <10°. We pattern a microarray of ‘sticky’ spots with a dramatically different sliding angle compared to that of the superhydrophobic region, enabling microtiter-plate type assays without the need for a well plate.

Localised anodic oxidation of aluminium material using a continuous electrolyte jet

NASA Astrophysics Data System (ADS)

Kuhn, D.; Martin, A.; Eckart, C.; Sieber, M.; Morgenstern, R.; Hackert-Oschätzchen, M.; Lampke, T.; Schubert, A.

2017-03-01

Anodic oxidation of aluminium and its alloys is often used as protection against material wearout and corrosion. Therefore, anodic oxidation of aluminium is applied to produce functional oxide layers. The structure and properties of the oxide layers can be influenced by various factors. These factors include for example the properties of the substrate material, like alloy elements and heat treatment or process parameters, like operating temperature, electric parameters or the type of the used electrolyte. In order to avoid damage to the work-piece surface caused by covering materials in masking applications, to minimize the use of resources and to modify the surface in a targeted manner, the anodic oxidation has to be localised to partial areas. Within this study a proper alternative without preparing the substrate by a mask is investigated for generating locally limited anodic oxidation by using a continuous electrolyte jet. Therefore aluminium material EN AW 7075 is machined by applying a continuous electrolyte jet of oxalic acid. Experiments were carried out by varying process parameters like voltage or processing time. The realised oxide spots on the aluminium surface were investigated by optical microscopy, SEM and EDX line scanning. Furthermore, the dependencies of the oxide layer properties from the process parameters are shown.

Progress in mask replication using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

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

2011-04-01

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

High resolution photolithography using arrays of polystyrene and SiO2 micro- and nano-sized spherical lenses

NASA Astrophysics Data System (ADS)

Dvoretckaia, L. N.; Mozharov, A. M.; Mukhin, I. S.

2017-11-01

Photolithography mask made of close-packed array of micro- and nano-sized spherical lenses allows to obtain the ordered structures and provides highest “optical resolution/cost” ratio between all existing photolithography and laser direct writing methods. In this letter, we present results of modeling the propagation of a plane wave falling on the array of quartz (SiO2) microspherical lenses and focusing in the image reverse photoresist layer. We present here experimental results on fabrication of ordered arrays of submicron wells and columns and substrate preparation for growth of monocrystalline nanowires on metal surface using photolithography with mask of SiO2 microspheres. Such ordered nano-sized arrays of wells and columns can be used in fabrication of further growth of monocrystalline nanowires, quantum dots and production of plasmon structures.

Photoresist composition for extreme ultraviolet lithography

DOEpatents

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

1999-01-01

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

Growth and transfer of monolithic horizontal nanowire superstructures onto flexible substrates

DOEpatents

Wang, Zhong L; Xu, Sheng

2013-08-27

In a method of making a monolithic elongated nanowire, a mask polymer layer is applied to a selected crystal surface of a seed crystal. A plurality of spaced apart elongated openings is defined through the mask polymer layer, thereby exposing a corresponding plurality of portions of the crystal surface. The openings are disposed so as to be aligned with and parallel to a selected crystal axis of the seed crystal. The portions of the crystal surface are subjected to a chemical nutrient environment that causes crystalline material to grow from the plurality of portions for at least a period of time so that monocrystalline members grow from the elongated openings and until the monocrystalline members laterally expand so that each monocrystalline member grows into and merges with an adjacent one of the monocrystalline members, thereby forming a monolithic elongated nanowire.

Soft x-ray reduction camera for submicron lithography

DOEpatents

Hawryluk, A.M.; Seppala, L.G.

1991-03-26

Soft x-ray projection lithography can be performed using x-ray optical components and spherical imaging lenses (mirrors), which form an x-ray reduction camera. The x-ray reduction is capable of projecting a 5x demagnified image of a mask onto a resist coated wafer using 4.5 nm radiation. The diffraction limited resolution of this design is about 135 nm with a depth of field of about 2.8 microns and a field of view of 0.2 cm[sup 2]. X-ray reflecting masks (patterned x-ray multilayer mirrors) which are fabricated on thick substrates and can be made relatively distortion free are used, with a laser produced plasma for the source. Higher resolution and/or larger areas are possible by varying the optic figures of the components and source characteristics. 9 figures.

New operational technology of intrauterine ventilation the fetus lungs by breathing gas

NASA Astrophysics Data System (ADS)

Urakov, A. L.; Nikityuk, D. B.; Urakova, N. A.; Kasankin, A. A.; Chernova, L. V.; Dementiev, V. B.

2015-11-01

New operational technology for elimination intrauterine hypoxia and asphyxia of the fetus using endoscopic artificial ventilation lungs by respiratory gas was developed. For intrauterine ventilation of fetal lung it is proposed to enter into the uterus a special breathing mask and wear it on the head of the fetus using the original endoscopic technology. The breathing mask, developed by us is connected with external breathing apparatus with a hose. The device is called "intrauterine aqualung". Intrauterine aqualung includes a ventilator and breathing circuit with a special fold-out breathing mask that is put on inside the uterus on the head of fetus like a mesh hat. Controlled by ultrasound the technology of the introduction of the mask inside of the uterus through the natural opening in the cervix and technology of putting on the respiratory mask on the head of the fetus with its head previa were developed. The technology intrauterine ventilation of the fetus lungs by respiratory gas was developed.

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

NASA Technical Reports Server (NTRS)

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

1997-01-01

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

A respiratory mask for resting and exercising dogs.

PubMed

Stavert, D M; Reischl, P; O'Loughlin, B J

1982-02-01

A respiratory face mask has been developed for use with unsedated beagles trained to run on a treadmill. The latex rubber mask, shaped to fit the animal's muzzle, incorporates two modified, commercially available, pulmonary valves for separating inspiratory and expiratory flows. The mask has a dead space of 30 cm3 and a flow resistance below 1 cmH2O . 1(-1) . s. The flexible mask is used to measure breath-by-breath respiratory variables over extended periods of time during rest and exercise.

Research on high-efficiency polishing technology of photomask substrate

NASA Astrophysics Data System (ADS)

Zhao, Shijie; Xie, Ruiqing; Zhou, Lian; Liao, Defeng; Chen, Xianhua; Wang, Jian

2018-03-01

A method of photomask substrate fabrication is demonstrated ,that the surface figure and roughness of fused silica will converge to target precision rapidly with the full aperture polishing. Surface figure of optical flats in full aperture polishing processes is primarily dependent on the surface profile of polishing pad, therefor, a improved function of polishing mechanism was put forward based on two axis lapping machine and technology experience, and the pad testing based on displacement sensor and the active conditioning method of the pad is applied in this research. Moreover , the clamping deformation of the thin glass is solved by the new pitch dispensing method. The experimental results show that the surface figure of the 152mm×152mm×6.35mm optical glass is 0.25λ(λ=633nm) and the roughness is 0.32nm ,which has meet the requirements of mask substrate for 90 45nm nodes.

Cross-stacked carbon nanotubes assisted self-separation of free-standing GaN substrates by hydride vapor phase epitaxy

NASA Astrophysics Data System (ADS)

Wei, Tongbo; Yang, Jiankun; Wei, Yang; Huo, Ziqiang; Ji, Xiaoli; Zhang, Yun; Wang, Junxi; Li, Jinmin; Fan, Shoushan

2016-06-01

We report a novel method to fabricate high quality 2-inch freestanding GaN substrate grown on cross-stacked carbon nanotubes (CSCNTs) coated sapphire by hydride vapor phase epitaxy (HVPE). As nanoscale masks, these CSCNTs can help weaken the interface connection and release the compressive stress by forming voids during fast coalescence and also block the propagation of threading dislocations (TDs). During the cool-down process, thermal stress-induced cracks are initiated at the CSCNTs interface with the help of air voids and propagated all over the films which leads to full self-separation of FS-GaN substrate. Raman and photoluminescence spectra further reveal the stress relief and crystalline improvement of GaN with CSCNTs. It is expected that the efficient, low cost and mass-producible technique may enable new applications for CNTs in nitride optoelectronic fields.

Photo-Spectrometer Realized In A Standard Cmos Ic Process

DOEpatents

Simpson, Michael L.; Ericson, M. Nance; Dress, William B.; Jellison, Gerald E.; Sitter, Jr., David N.; Wintenberg, Alan L.

1999-10-12

A spectrometer, comprises: a semiconductor having a silicon substrate, the substrate having integrally formed thereon a plurality of layers forming photo diodes, each of the photo diodes having an independent spectral response to an input spectra within a spectral range of the semiconductor and each of the photo diodes formed only from at least one of the plurality of layers of the semiconductor above the substrate; and, a signal processing circuit for modifying signals from the photo diodes with respective weights, the weighted signals being representative of a specific spectral response. The photo diodes have different junction depths and different polycrystalline silicon and oxide coverings. The signal processing circuit applies the respective weights and sums the weighted signals. In a corresponding method, a spectrometer is manufactured by manipulating only the standard masks, materials and fabrication steps of standard semiconductor processing, and integrating the spectrometer with a signal processing circuit.

Lateral epitaxial overgowth of GaAs by organometallic chemical vapor deposition

NASA Technical Reports Server (NTRS)

Gale, R. P.; Mcclelland, R. W.; Fan, J. C. C.; Bozler, C. O.

1982-01-01

Lateral epitaxial overgrowth of GaAs by organometallic chemical vapor deposition has been demonstrated. Pyrolytic decomposition of trimethylgallium and arsine, without the use of HCl, was used to deposit GaAs on substrates prepared by coating (110) GaAs wafers with SiO2, then using photolithography to open narrow stripes in the oxide. Lateral overgrowth was seeded by epitaxial deposits formed on the GaAs surfaces exposed by the stripe openings. The extent of lateral overgrowth was investigated as a function of stripe orientation and growth temperature. Ratios of lateral to vertical growth rates greater than five have been obtained. The lateral growth is due to surface-kinetic control for the two-dimensional growth geometry studied. A continuous epitaxial GaAs layer 3 microns thick has been grown over a patterned mask on a GaAs substrate and then cleaved from the substrate.

Cross-stacked carbon nanotubes assisted self-separation of free-standing GaN substrates by hydride vapor phase epitaxy.

PubMed

Wei, Tongbo; Yang, Jiankun; Wei, Yang; Huo, Ziqiang; Ji, Xiaoli; Zhang, Yun; Wang, Junxi; Li, Jinmin; Fan, Shoushan

2016-06-24

We report a novel method to fabricate high quality 2-inch freestanding GaN substrate grown on cross-stacked carbon nanotubes (CSCNTs) coated sapphire by hydride vapor phase epitaxy (HVPE). As nanoscale masks, these CSCNTs can help weaken the interface connection and release the compressive stress by forming voids during fast coalescence and also block the propagation of threading dislocations (TDs). During the cool-down process, thermal stress-induced cracks are initiated at the CSCNTs interface with the help of air voids and propagated all over the films which leads to full self-separation of FS-GaN substrate. Raman and photoluminescence spectra further reveal the stress relief and crystalline improvement of GaN with CSCNTs. It is expected that the efficient, low cost and mass-producible technique may enable new applications for CNTs in nitride optoelectronic fields.

Cross-stacked carbon nanotubes assisted self-separation of free-standing GaN substrates by hydride vapor phase epitaxy

PubMed Central

Wei, Tongbo; Yang, Jiankun; Wei, Yang; Huo, Ziqiang; Ji, Xiaoli; Zhang, Yun; Wang, Junxi; Li, Jinmin; Fan, Shoushan

2016-01-01

We report a novel method to fabricate high quality 2-inch freestanding GaN substrate grown on cross-stacked carbon nanotubes (CSCNTs) coated sapphire by hydride vapor phase epitaxy (HVPE). As nanoscale masks, these CSCNTs can help weaken the interface connection and release the compressive stress by forming voids during fast coalescence and also block the propagation of threading dislocations (TDs). During the cool-down process, thermal stress-induced cracks are initiated at the CSCNTs interface with the help of air voids and propagated all over the films which leads to full self-separation of FS-GaN substrate. Raman and photoluminescence spectra further reveal the stress relief and crystalline improvement of GaN with CSCNTs. It is expected that the efficient, low cost and mass-producible technique may enable new applications for CNTs in nitride optoelectronic fields. PMID:27340030

Improved light extraction efficiency of GaN-based flip-chip light-emitting diodes with an antireflective interface layer

NASA Astrophysics Data System (ADS)

Wu, Dongxue; Ma, Ping; Liu, Boting; Zhang, Shuo; Wang, Junxi; Li, Jinmin

2016-05-01

GaN-based flip-chip light-emitting diodes (FC-LEDs) grown on nanopatterned sapphire substrates (NPSS) are fabricated using self-assembled SiO2 nanospheres as masks during inductively coupled plasma etching. By controlling the pattern spacing, epitaxial GaN can be grown from the top or bottom of patterns to obtain two different GaN/substrate interfaces. The optoelectronic characteristics of FC-LED chips with different GaN/sapphire interfaces are studied. The FC-LED with an antireflective interface layer consisting of a NPSS with GaN in the pattern spacings demonstrates better optical properties than the FC-LED with an interface embedded with air voids. Our study indicates that the two types of FC-LEDs grown on NPSS show higher crystal quality and improved electrical and optical characteristics compared with those of FC-LEDs grown on conventional planar sapphire substrates.

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.

Toward Deterministic Implantation of Nitrogen Vacancy Centers in Bulk Diamond Crystals

NASA Astrophysics Data System (ADS)

Brundage, T. O.; Atkins, Z.; Sangtawesin, S.; Petta, J. R.

2014-03-01

Over the last decade, research investigating the room temperature stability, coherence, and optical manipulation of spin states of the nitrogen vacancy (NV) center in diamond has made it a strong candidate for applications in magnetometry and quantum information processing. As research progresses and we begin to investigate the dynamics and scalability of multiple NV systems, the ability to place NV centers deterministically in the host material with high accuracy is critical. Here we implement a simple fabrication method for NV implantation. We expose and develop small dots in PMMA using an electron-beam lithography tool. Unexposed PMMA serves as a mask for 20 keV nitrogen-15 implantation. The implanted sample is then cleaned in a boiling mixture of nitric, sulfuric, and perchloric acid. Annealing at 850° for 2 hours allows vacancies to diffuse next to implanted nitrogen atoms, forming NV centers with an efficiency of a few percent. SRIM simulations provide nitrogen ion distribution within our diamond substrate and PMMA mask as functions of implantation energy. Thus, after balancing implantation parameters and exposure hole cross-sections, NV center placement can be achieved with accuracy limited by the precision of available electron-beam lithography equipment. Supported by the Sloan and Packard Foundations, the Army Research Office, and the National Science Foundation.

Programmable 2-D Addressable Cryogenic Aperture Masks

NASA Technical Reports Server (NTRS)

Kutyrev, A. S.; Moseley, S. H.; Jhabvala, M.; Li, M.; Schwinger, D. S.; Silverberg, R. F.; Wesenberg, R. P.

2004-01-01

We are developing a two-dimensional array of square microshutters (programmable aperture mask) for a multi-object spectrometer for the James Webb Space Telescope (JWST). This device will provide random access selection of the areas in the field to be studied. The device is in essence a close packed array of square slits, each of which can be opened independently to select areas of the sky for detailed study.The device is produced using a 100-micron thick silicon wafer as a substrate with 0.5-micron thick silicon nitride shutters on top of it. Silicon nitride has been selected as the blade and flexure material because its stiffness allows thinner and lighter structures than single crystal Si, the chief alternative, and because of its ease of manufacture. The 100 micron silicon wafer is backetched in a high aspect ratio Deep Reactive Ion Etching (Deep RIE) to leave only a support grid for the shutters and the address electronics. The shutter actuation is done magnetically whereas addressing is electrostatic. 128x128 format microshutter arrays have been produced. Their operation has been demostarted on 32x32 subarrays. Good reliability of the fabrication process and good quality of the microshutters has been achieved. The mechanical behavior and optical performance of the fabricated arrays at cryogenic temperature are being studied.

Mask CD relationship to temperature at the time backscatter is received

NASA Astrophysics Data System (ADS)

Zable, Harold; Kronmiller, Tom; Pearman, Ryan; Guthrie, Bill; Shirali, Nagesh; Masuda, Yukihiro; Kamikubo, Takashi; Nakayamada, Noriaki; Fujimura, Aki

2017-07-01

Mask writers need to be able to write sub-50nm features accurately. Nano-imprint lithography (NIL) masters need to create sub-20nm line and space (L:S) patterns reliably. Increasingly slower resists are deployed, but mask write times need to remain reasonable. The leading edge EBM-9500 offers 1200A/cm2 current density to shoot variable shaped beam (VSB) to write the masks. Last year, thermal effect correction (TEC) was introduced by NuFlare in the EBM-95001. It is a GPU-accelerated inline correction for the effect that the temperature of the resist has on CD. For example, a 100nm CD may print at 102nm where that area was at a comparably high temperature at the time of the shot. Since thermal effect is a temporal effect, the simulated temperature of the surface of the mask is dynamically updated for the effect of each shot in order to accurately predict the cumulative effect that is the temperature at the location of the shot at the time of the shot and therefore its impact on CD. The shot dose is changed to reverse the effects of the temperature change. This paper for the first time reveals an enhancement to this thermal model and a simulator for it. It turns out that the temperature at the time each location receives backscatter from other shots also make a difference to the CD. The effect is secondary, but still measurable for some resists and substrates. Results of a test-chip study will be presented. The computation required for the backscatter effect is substantial. It has been demonstrated that this calculation can be performed fast enough to be inline with the EBM-9500 with a reasonable-sized computing platform. Run-time results and the computing architecture will be presented.

Design And Demonstration Of Band-limited Hybrid Coronagraph Masks For Space Imaging And Spectroscopy Of Exoplanetary Systems

NASA Astrophysics Data System (ADS)

Trauger, John T.; Moody, D. C.

2010-05-01

Among the leading architectures for the imaging and spectroscopy of nearby exoplanetary systems is the space coronagraph, which provides in principle very high (10 billion to one) suppression of diffracted and scattered starlight at very small separations (a few tenths of arcseconds) from the star. The concept of a band-limited Lyot coronagraph, introduced by Kuchner and Traub (2002), provides the theoretical basis for mathematically perfect starlight suppression. In practice, the optical characteristics of available materials and practical aspects of the fabrication processes impose limitations on contrast and spectral bandwidths that are achievable in the real world. Nevertheless, the band-limited Lyot coronagraph approach has produced the best laboratory validated performance among known types of internal coronagraph for contrast and spectral bandwidth, and alone it has demonstrated high-contrast imaging performance at levels required for exoplanet exploration. We report the design and fabrication of hybrid focal-plane masks for Lyot coronagraphy, composed of thickness-profiled metallic and dielectric thin films, vacuum deposited on a glass substrate. These masks are in principle band-limited in both the real and imaginary parts of the complex amplitude characteristics. Together with a deformable mirror for control of wavefront phase, these masks have the potential for contrast performance better than 10-9 at inner working angles of 3 lambda/D or better over spectral bandwidths of 20% or more, and with throughput efficiencies up to 60%. We report recent laboratory demonstrations of high contrast with nickel-dielectric masks, including the demonstration of 2x10-9 contrast with a 3 lambda/D inner working angle over 20% spectral bandwidths.

Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects

NASA Astrophysics Data System (ADS)

Ye, Zhou; Nain, Amrinder S.; Behkam, Bahareh

2016-06-01

Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features.Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features. Electronic supplementary information (ESI) available: SWAN lithography on silicon; comparison of SWAN lithography and state-of-the-art nanopatterning methods; replica molding using SWAN lithography fabricated template; PDMS nanofluidic device, gold nanopattern characterization. See DOI: 10.1039/c6nr03323g

Mask manufacturing improvement through capability definition and bottleneck line management

NASA Astrophysics Data System (ADS)

Strott, Al

1994-02-01

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

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

NASA Astrophysics Data System (ADS)

Li, Jia; Lam, Edmund Y.

2014-03-01

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

Laser patterning of highly conductive flexible circuits

NASA Astrophysics Data System (ADS)

Ji, Seok Young; Muhammed Ajmal, C.; Kim, Taehun; Chang, Won Seok; Baik, Seunghyun

2017-04-01

There has been considerable attention paid to highly conductive flexible adhesive (CFA) materials as electrodes and interconnectors for future flexible electronic devices. However, the patterning technology still needs to be developed to construct micro-scale electrodes and circuits. Here we developed the selective laser sintering technology where the pattering and curing were accomplished simultaneously without making additional masks. The CFA was composed of micro-scale Ag flakes, multiwalled carbon nanotubes decorated with Ag nanoparticles, and a nitrile-butadiene-rubber matrix. The Teflon-coated polyethylene terephthalate film was used as a flexible substrate. The width of lines (50-500 μm) and circuit patterns were controlled by the programmable scanning of a focused laser beam (power = 50 mW, scanning speed = 1 mm s-1). The laser irradiation removed solvent and induced effective coalescence among fillers providing a conductivity as high as 25 012 S cm-1. The conductivity stability was excellent under the ambient air and humid environments. The normalized resistance change of the pattern was smaller than 1.2 at the bending radius of 5 mm. The cyclability and adhesion of the laser-sintered line pattern on the substrate was excellent. A flexible circuit was fabricated sequentially for operating light emitting diodes during the bending motion, demonstrating excellent feasibility for practical applications in flexible electronics.

Laser patterning of highly conductive flexible circuits.

PubMed

Ji, Seok Young; Ajmal, C Muhammed; Kim, Taehun; Chang, Won Seok; Baik, Seunghyun

2017-04-21

There has been considerable attention paid to highly conductive flexible adhesive (CFA) materials as electrodes and interconnectors for future flexible electronic devices. However, the patterning technology still needs to be developed to construct micro-scale electrodes and circuits. Here we developed the selective laser sintering technology where the pattering and curing were accomplished simultaneously without making additional masks. The CFA was composed of micro-scale Ag flakes, multiwalled carbon nanotubes decorated with Ag nanoparticles, and a nitrile-butadiene-rubber matrix. The Teflon-coated polyethylene terephthalate film was used as a flexible substrate. The width of lines (50-500 μm) and circuit patterns were controlled by the programmable scanning of a focused laser beam (power = 50 mW, scanning speed = 1 mm s -1 ). The laser irradiation removed solvent and induced effective coalescence among fillers providing a conductivity as high as 25 012 S cm -1 . The conductivity stability was excellent under the ambient air and humid environments. The normalized resistance change of the pattern was smaller than 1.2 at the bending radius of 5 mm. The cyclability and adhesion of the laser-sintered line pattern on the substrate was excellent. A flexible circuit was fabricated sequentially for operating light emitting diodes during the bending motion, demonstrating excellent feasibility for practical applications in flexible electronics.

X Ray Mask Of Gold-Carbon Mixture Absorber On BCN Compound Substrate Fabricated By Plasma Processes

NASA Astrophysics Data System (ADS)

Aiyer, Chandrasekhar R.; Itoh, Satoshi; Yamada, Hitomi; Morita, Shinzo; Hattori, Shuzo

1988-06-01

X-ray mask fabrication based on BCN compound membrane and gold containing polymeric carbon ( Au-C ) absorber by totally dry processes is proposed. The Au-C films were depo-sited by plasma polymerization of propylene or styrene monomers and co-evaporation of gold. These films have 2 to 5 times higher etching rate than that of pure gold for 09 RIE, depending on the Au content. The stress in the films could be reduced to 1.9 E 7 N/m2 by annealing. The BCN films were deposited on silicon wafers by rf (13.56 MHz) plasma CVD with diborane, methane and nitrogen as source gases at typical deposition rate of 30 nm/min. The optical (633nm) and X ray (Pd L~) transparencies were nearly 80% for film thickness of 6 um. Patterning of Au-C was achieved by using tungsten as intermediate layer and PMMA electron beam resist. CF4 RIE was used to etch the tungsten layer which in turn acted as mask for the gold carbide 02 RIE. The process parameters and the characteristics of the Au-C and BCN films are presented.

A study of an alignment-less lithography method as an educational resource

NASA Astrophysics Data System (ADS)

Kai, Kazuho; Shiota, Koki; Nagaoka, Shiro; Mahmood, Mohamad Rusop Bin Haji; Kawai, Akira

2016-07-01

A simplification of the lithography process was studied. The simplification method of photolithography, named "alignment-less lithography" was proposed by omitting the photomask alignment process in photolithography process using mechanically aligned photomasks and substrate by using a simple jig on which countersinks were formed. Photomasks made of glass and the photomasks made of transparent plastic sheets were prepared for the process. As the result, approximately 5µm in the case of the glass mask, and 20µm in the case of the OHP mask were obtained with repetitive accuracies, respectively. It was confirmed that the alignment-less lithography method was successful. The possibility of the application to an educational program, such as a heuristic for solving problems was suggested using the method with the OHP mask. The nMOS FET fabrication process was successfully demonstrated using this method. The feasibility of this process was confirmed. It is expected that a totally simplified device fabrication process can be achievable when combined with other simplifications, such ass the simplified impurity diffusion processes using PSG and BSG thin film as diffusion source prepared by the Sol-Gel material under normal air environment.

Challenges and the state of the technology for printed sensor arrays for structural monitoring

NASA Astrophysics Data System (ADS)

Joshi, Shiv; Bland, Scott; DeMott, Robert; Anderson, Nickolas; Jursich, Gregory

2017-04-01

Printed sensor arrays are attractive for reliable, low-cost, and large-area mapping of structural systems. These sensor arrays can be printed on flexible substrates or directly on monitored structural parts. This technology is sought for continuous or on-demand real-time diagnosis and prognosis of complex structural components. In the past decade, many innovative technologies and functional materials have been explored to develop printed electronics and sensors. For example, an all-printed strain sensor array is a recent example of a low-cost, flexible and light-weight system that provides a reliable method for monitoring the state of aircraft structural parts. Among all-printing techniques, screen and inkjet printing methods are well suited for smaller-scale prototyping and have drawn much interest due to maturity of printing procedures and availability of compatible inks and substrates. Screen printing relies on a mask (screen) to transfer a pattern onto a substrate. Screen printing is widely used because of the high printing speed, large selection of ink/substrate materials, and capability of making complex multilayer devices. The complexity of collecting signals from a large number of sensors over a large area necessitates signal multiplexing electronics that need to be printed on flexible substrate or structure. As a result, these components are subjected to same deformation, temperature and other parameters for which sensor arrays are designed. The characteristics of these electronic components, such as transistors, are affected by deformation and other environmental parameters which can lead to erroneous sensed parameters. The manufacturing and functional challenges of the technology of printed sensor array systems for structural state monitoring are the focus of this presentation. Specific examples of strain sensor arrays will be presented to highlight the technical challenges.

Development for 2D pattern quantification method on mask and wafer

NASA Astrophysics Data System (ADS)

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

2010-03-01

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

Hierarchical brain tissue segmentation and its application in multiple sclerosis and Alzheimer's disease

NASA Astrophysics Data System (ADS)

Lei, Tianhu; Udupa, Jayaram K.; Moonis, Gul; Schwartz, Eric; Balcer, Laura

2005-04-01

Based on Fuzzy Connectedness (FC) object delineation principles and algorithms, a hierarchical brain tissue segmentation technique has been developed for MR images. After MR image background intensity inhomogeneity correction and intensity standardization, three FC objects for cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) are generated via FC object delineation, and an intracranial (IC) mask is created via morphological operations. Then, the IC mask is decomposed into parenchymal (BP) and CSF masks, while the BP mask is separated into WM and GM masks. WM mask is further divided into pure and dirty white matter masks (PWM and DWM). In Multiple Sclerosis studies, a severe white matter lesion (LS) mask is defined from DWM mask. Based on the segmented brain tissue images, a histogram-based method has been developed to find disease-specific, image-based quantitative markers for characterizing the macromolecular manifestation of the two diseases. These same procedures have been applied to 65 MS (46 patients and 19 normal subjects) and 25 AD (15 patients and 10 normal subjects) data sets, each of which consists of FSE PD- and T2-weighted MR images. Histograms representing standardized PD and T2 intensity distributions and their numerical parameters provide an effective means for characterizing the two diseases. The procedures are systematic, nearly automated, robust, and the results are reproducible.

An improved method for determining the efficiency of crew and passenger oxygen masks.

DOT National Transportation Integrated Search

1962-11-01

A method for determining oxygen mask leakage as developed under contract FA-885 between the Federal Aviation Agency and the Pioneer-Central Division of the Bendix Corporation was evaluated. Measurement of nitrogen concentration within an oxygen mask ...

Tape transfer atomization patterning of liquid alloys for microfluidic stretchable wireless power transfer.

PubMed

Jeong, Seung Hee; Hjort, Klas; Wu, Zhigang

2015-02-12

Stretchable electronics offers unsurpassed mechanical compliance on complex or soft surfaces like the human skin and organs. To fully exploit this great advantage, an autonomous system with a self-powered energy source has been sought for. Here, we present a new technology to pattern liquid alloys on soft substrates, targeting at fabrication of a hybrid-integrated power source in microfluidic stretchable electronics. By atomized spraying of a liquid alloy onto a soft surface with a tape transferred adhesive mask, a universal fabrication process is provided for high quality patterns of liquid conductors in a meter scale. With the developed multilayer fabrication technique, a microfluidic stretchable wireless power transfer device with an integrated LED was demonstrated, which could survive cycling between 0% and 25% strain over 1,000 times.

Tape Transfer Atomization Patterning of Liquid Alloys for Microfluidic Stretchable Wireless Power Transfer

PubMed Central

Jeong, Seung Hee; Hjort, Klas; Wu, Zhigang

2015-01-01

Stretchable electronics offers unsurpassed mechanical compliance on complex or soft surfaces like the human skin and organs. To fully exploit this great advantage, an autonomous system with a self-powered energy source has been sought for. Here, we present a new technology to pattern liquid alloys on soft substrates, targeting at fabrication of a hybrid-integrated power source in microfluidic stretchable electronics. By atomized spraying of a liquid alloy onto a soft surface with a tape transferred adhesive mask, a universal fabrication process is provided for high quality patterns of liquid conductors in a meter scale. With the developed multilayer fabrication technique, a microfluidic stretchable wireless power transfer device with an integrated LED was demonstrated, which could survive cycling between 0% and 25% strain over 1,000 times. PMID:25673261

High-throughput characterization of film thickness in thin film materials libraries by digital holographic microscopy.

PubMed

Lai, Yiu Wai; Krause, Michael; Savan, Alan; Thienhaus, Sigurd; Koukourakis, Nektarios; Hofmann, Martin R; Ludwig, Alfred

2011-10-01

A high-throughput characterization technique based on digital holography for mapping film thickness in thin-film materials libraries was developed. Digital holographic microscopy is used for fully automatic measurements of the thickness of patterned films with nanometer resolution. The method has several significant advantages over conventional stylus profilometry: it is contactless and fast, substrate bending is compensated, and the experimental setup is simple. Patterned films prepared by different combinatorial thin-film approaches were characterized to investigate and demonstrate this method. The results show that this technique is valuable for the quick, reliable and high-throughput determination of the film thickness distribution in combinatorial materials research. Importantly, it can also be applied to thin films that have been structured by shadow masking.

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.

Use of KRS-XE positive chemically amplified resist for optical mask manufacturing

NASA Astrophysics Data System (ADS)

Ashe, Brian; Deverich, Christina; Rabidoux, Paul A.; Peck, Barbara; Petrillo, Karen E.; Angelopoulos, Marie; Huang, Wu-Song; Moreau, Wayne M.; Medeiros, David R.

2002-03-01

The traditional mask making process uses chain scission-type resists such as PBS, poly(butene-1-sulfone), and ZEP, poly(methyl a-chloroacrylate-co-a-methylstyrene) for making masks with dimensions greater than 180nm. PBS resist requires a wet etch process to produce patterns in chrome. ZEP was employed for dry etch processing to meet the requirements of shrinking dimensions, optical proximity corrections and phase shift masks. However, ZEP offers low contrast, marginal etch resistance, organic solvent development, and concerns regarding resist heating with its high dose requirements1. Chemically Amplified Resist (CAR) systems are a very good choice for dimensions less than 180nm because of their high sensitivity and contrast, high resolution, dry etch resistance, aqueous development, and process latitude2. KRS-XE was developed as a high contrast CA resist based on ketal protecting groups that eliminate the need for post exposure bake (PEB). This resist can be used for a variety of electron beam exposures, and improves the capability to fabricate masks for devices smaller than 180nm. Many factors influence the performance of resists in mask making such as post apply bake, exposure dose, resist develop, and post exposure bake. These items will be discussed as well as the use of reactive ion etching (RIE) selectivity and pattern transfer.

The Neural Substrate for Binaural Masking Level Differences in the Auditory Cortex

PubMed Central

Gilbert, Heather J.; Krumbholz, Katrin; Palmer, Alan R.

2015-01-01

The binaural masking level difference (BMLD) is a phenomenon whereby a signal that is identical at each ear (S0), masked by a noise that is identical at each ear (N0), can be made 12–15 dB more detectable by inverting the waveform of either the tone or noise at one ear (Sπ, Nπ). Single-cell responses to BMLD stimuli were measured in the primary auditory cortex of urethane-anesthetized guinea pigs. Firing rate was measured as a function of signal level of a 500 Hz pure tone masked by low-passed white noise. Responses were similar to those reported in the inferior colliculus. At low signal levels, the response was dominated by the masker. At higher signal levels, firing rate either increased or decreased. Detection thresholds for each neuron were determined using signal detection theory. Few neurons yielded measurable detection thresholds for all stimulus conditions, with a wide range in thresholds. However, across the entire population, the lowest thresholds were consistent with human psychophysical BMLDs. As in the inferior colliculus, the shape of the firing-rate versus signal-level functions depended on the neurons' selectivity for interaural time difference. Our results suggest that, in cortex, BMLD signals are detected from increases or decreases in the firing rate, consistent with predictions of cross-correlation models of binaural processing and that the psychophysical detection threshold is based on the lowest neural thresholds across the population. PMID:25568115

Captive breeding and reintroduction of the endangered masked bobwhite

USGS Publications Warehouse

Carpenter, J.W.; Gabel, R.R.; Goodwin, J.G.

1991-01-01

Efforts to restore the endangered masked bobwhite (Colinus virginianus ridgwayi) to its former range have required 1) habitat acquisition, restoration, and preservation; 2) captive propagation; and 3) reintroduction .bf captive-bred stock. In its role to recover the masked bobwhite, the Patuxent Wildlife Research Center (U.S. Fish and Wildli e Service) has refined captive breeding techniques; provided captive-produced stock for release; conducted field research on the distribution, limiting factors, and habitat characteristics of this species; and developed release methods. Techniques for the husbandry and captive management, breeding, artificial incubation and hatching of eggs, and rearing of young of the masked bobwhite have been developed. Successful reintroduction techniques for the masked bobwhite have included prerelease conditioning and/or cross-fostering of captive-reared masked bobwhite chicks to a wild-caught, related, vasectomized bobwhite species and their release to the wild as family units. In addition, the establishment by the U. S. Fish and Wildlife Service of the Buenos Aires National Wildlife Refuge in 1985 has further enhanced the potential for establishing a self-sustaining population of the masked bobwhite in the U. S. Through continued releases and active management of habitat, therefore, it is believed that the masked bobwhite can become permanently established at the refuge to ensure its continued survival in the wild.

Design criteria for small coded aperture masks in gamma-ray astronomy

NASA Technical Reports Server (NTRS)

Sembay, S.; Gehrels, Neil

1990-01-01

Most theoretical work on coded aperture masks in X-ray and low-energy gamma-ray astronomy has concentrated on masks with large numbers of elements. For gamma-ray spectrometers in the MeV range, the detector plane usually has only a few discrete elements, so that masks with small numbers of elements are called for. For this case it is feasible to analyze by computer all the possible mask patterns of given dimension to find the ones that best satisfy the desired performance criteria. A particular set of performance criteria for comparing the flux sensitivities, source positioning accuracies and transparencies of different mask patterns is developed. The results of such a computer analysis for masks up to dimension 5 x 5 unit cell are presented and it is concluded that there is a great deal of flexibility in the choice of mask pattern for each dimension.

Marquardt’s Facial Golden Decagon Mask and Its Fitness with South Indian Facial Traits

PubMed Central

Gandikota, Chandra Sekhar; Yadagiri, Poornima K; Manne, Ranjit; Juvvadi, Shubhaker Rao; Farah, Tamkeen; Vattipelli, Shilpa; Gumbelli, Sangeetha

2016-01-01

Introduction The mathematical ratio of 1:1.618 which is famously known as golden ratio seems to appear recurrently in beautiful things in nature as well as in other things that are seen as beautiful. Dr. Marquardt developed a facial golden mask that contains and includes all of the one-dimensional and two-dimensional geometric golden elements formed from the golden ratio and he claimed that beauty is universal, beautiful faces conforms to the facial golden mask regardless of sex and race. Aim The purpose of this study was to evaluate the goodness of fit of the golden facial mask with the South Indian facial traits. Materials and Methods A total of 150 subjects (75 males & 75 females) with attractive faces were selected with cephalometric orthodontic standards of a skeletal class I relation. The facial aesthetics was confirmed by the aesthetic evaluation of the frontal photographs of the subjects by a panel of ten evaluators including five orthodontists and five maxillofacial surgeons. The well-proportioned photographs were superimposed with the Golden mask along the reference lines, to evaluate the goodness of fit. Results South Indian males and females invariably show a wider inter-zygomatic and inter-gonial width than the golden mask. Most of the South Indian females and males show decreased mid-facial height compared to the golden mask, while the total facial height is more or less equal to the golden mask. Conclusion Ethnic or individual discrepancies cannot be totally ignored as in our study the mask did not fit exactly with the South Indian facial traits but, the beauty ratios came closer to those of the mask. To overcome this difficulty, there is a need to develop variants of golden facial mask for different ethnic groups. PMID:27190951

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

PubMed

Li, Jia; Lam, Edmund Y

2014-04-21

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

Development of a low-cost x-ray mask for high-aspect-ratio MEM smart structures

NASA Astrophysics Data System (ADS)

Ajmera, Pratul K.; Stadler, Stefan; Abdollahi, Neda

1998-07-01

A cost-effective process with short fabrication time for making x-ray masks for research and development purposes is described here for fabricating high-aspect ratio microelectromechanical structures using synchrotron based x- ray lithography. Microscope cover glass slides as membrane material is described. Slides with an initial thickness of 175 micrometers are etched to a thickness in the range of 10 - 25 micrometers using a diluted HF and buffered hydrofluoric acid solutions. The thinned slides are glued on supportive mask frames and sputtered with a chromium/silver sandwich layer which acts as a plating base layer for the deposition of the gold absorber. The judicial choice of glue and mask frame material are significant parameters in a successful fabrication process. Gold absorber structures are electroplated on the membrane. Calculations are done for contrast and dose ratio obtained in the photoresist after synchrotron radiation as a function of the mask design parameters. Exposure experiments are performed to prove the applicability of the fabricated x-ray mask.

Photocatalytic performance of highly amorphous titania-silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

NASA Astrophysics Data System (ADS)

Lázár, István; Kalmár, József; Peter, Anca; Szilágyi, Anett; Győri, Enikő; Ditrói, Tamás; Fábián, István

2015-11-01

Titania-silica composite aerogels with 16-29% Ti-content by the mass were synthesized by the sol-gel method from different Ti-precursors, and calcined at 500 °C. These aerogels are highly amorphous as no crystalline TiO2 phase can be detected in them by X-ray diffraction methods, and show the dominating presence of either mesopores or macropores. The incorporation of Ti into the silica structure is shown by the appearance of characteristic IR transitions of Sisbnd Osbnd Ti vibrations. The characteristic band-gap energies of the different aerogels are estimated to be between 3.6 and 3.9 eV from UV reflection spectra. Band-gap energy decreases with decreasing pore-size. When suspended in solution, even these highly amorphous aerogels accelerate the photodegradation of salicylic acid and methylene blue compared to simple photolysis. Kinetic experiments were conducted under illumination, and also in the dark to study the adsorption of the substrates onto the suspended aerogels. We assume that the fast in situ adsorption of the organic substrates mask the suspended aerogel particles from UV photons, which reduces the rate of photocatalysis. We managed to mathematically separate the parallel processes of photocatalysis and adsorption, and develop a simple kinetic model to describe the reaction system.

Precision process calibration and CD predictions for low-k1 lithography

NASA Astrophysics Data System (ADS)

Chen, Ting; Park, Sangbong; Berger, Gabriel; Coskun, Tamer H.; de Vocht, Joep; Chen, Fung; Yu, Linda; Hsu, Stephen; van den Broeke, Doug; Socha, Robert; Park, Jungchul; Gronlund, Keith; Davis, Todd; Plachecki, Vince; Harris, Tom; Hansen, Steve; Lambson, Chuck

2005-06-01

Leading resist calibration for sub-0.3 k1 lithography demands accuracy <2nm for CD through pitch. An accurately calibrated resist process is the prerequisite for establishing production-worthy manufacturing under extreme low k1. From an integrated imaging point of view, the following key components must be simultaneously considered during the calibration - high numerical aperture (NA>0.8) imaging characteristics, customized illuminations (measured vs. modeled pupil profiles), resolution enhancement technology (RET) mask with OPC, reticle metrology, and resist thin film substrate. For imaging at NA approaching unity, polarized illumination can impact significantly the contrast formation in the resist film stack, and therefore it is an important factor to consider in the CD-based resist calibration. For aggressive DRAM memory core designs at k1<0.3, pattern-specific illumination optimization has proven to be critical for achieving the required imaging performance. Various optimization techniques from source profile optimization with fixed mask design to the combined source and mask optimization have been considered for customer designs and available imaging capabilities. For successful low-k1 process development, verification of the optimization results can only be made with a sufficiently tunable resist model that can predicate the wafer printing accurately under various optimized process settings. We have developed, for resist patterning under aggressive low-k1 conditions, a novel 3D diffusion model equipped with double-Gaussian convolution in each dimension. Resist calibration with the new diffusion model has demonstrated a fitness and CD predication accuracy that rival or outperform the traditional 3D physical resist models. In this work, we describe our empirical approach to achieving the nm-scale precision for advanced lithography process calibrations, using either measured 1D CD through-pitch or 2D memory core patterns. We show that for ArF imaging, the current resist development and diffusion modeling can readily achieve ~1-2nm max CD errors for common 1D through-pitch and aggressive 2D memory core resist patterns. Sensitivities of the calibrated models to various process parameters are analyzed, including the comparison between the measured and modeled (Gaussian or GRAIL) pupil profiles. We also report our preliminary calibration results under selected polarized illumination conditions.

Large area InN terahertz emitters based on the lateral photo-Dember effect

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

Wallauer, Jan, E-mail: jan.wallauer@fmf.uni-freiburg.de; Grumber, Christian; Walther, Markus

2015-09-14

Large area terahertz emitters based on the lateral photo-Dember effect in InN (indium nitride) are presented. The formation of lateral photo-Dember currents is induced by laser-illumination through a microstructured metal cover processed onto the InN substrate, causing an asymmetry in the lateral photogenerated charge carrier distribution. Our design uses simple metal structures, which are produced by conventional two-dimensional micro-structuring techniques. Having favoring properties as a photo-Dember material InN is particularly well-suited as a substrate for our emitters. We demonstrate that the emission intensity of the emitters can be significantly influenced by the structure of the metal cover leaving room formore » improvement by optimizing the masking structures.« less

Si substrates texturing and vapor-solid-solid Si nanowhiskers growth using pure hydrogen as source gas

NASA Astrophysics Data System (ADS)

Nordmark, H.; Nagayoshi, H.; Matsumoto, N.; Nishimura, S.; Terashima, K.; Marioara, C. D.; Walmsley, J. C.; Holmestad, R.; Ulyashin, A.

2009-02-01

Scanning and transmission electron microscopies have been used to study silicon substrate texturing and whisker growth on Si substrates using pure hydrogen source gas in a tungsten hot filament reactor. Substrate texturing, in the nanometer to micrometer range of mono- and as-cut multicrystalline silicon, was observed after deposition of WSi2 particles that acted as a mask for subsequent hydrogen radical etching. Simultaneous Si whisker growth was observed for long residence time of the source gas and low H2 flow rate with high pressure. The whiskers formed via vapor-solid-solid growth, in which the deposited WSi2 particles acted as catalysts for a subsequent metal-induced layer exchange process well below the eutectic temperature. In this process, SiHx species, formed by substrate etching by the H radicals, diffuse through the metal particles. This leads to growth of crystalline Si whiskers via metal-induced solid-phase crystallization. Transmission electron microscopy, electron diffraction, and x-ray energy dispersive spectroscopy were used to study the WSi2 particles and the structure of the Si substrates in detail. It has been established that the whiskers are partly crystalline and partly amorphous, consisting of pure Si with WSi2 particles on their tips as well as sometimes being incorporated into their structure.

High Contrast Internal and External Coronagraph Masks Produced by Various Techniques

NASA Technical Reports Server (NTRS)

Balasubramanian, Kunjithapatha; Wilson, Daniel; White, Victor; Muller, Richard; Dickie, Matthew; Yee, Karl; Ruiz, Ronald; Shaklan, Stuart; Cady, Eric; Kern, Brian;

The automated array assembly task of the low-cost silicon solar array project, phase 2

NASA Technical Reports Server (NTRS)

Coleman, M. G.; Pryor, R. A.; Sparks, T. G.; Legge, R.; Saltzman, D. L.

1980-01-01

Several specific processing steps as part of a total process sequence for manufacturing silicon solar cells were studied. Ion implantation was identified as the preferred process step for impurity doping. Unanalyzed beam ion implantation was shown to have major cost advantages over analyzed beam implantation. Further, high quality cells were fabricated using a high current unanalyzed beam. Mechanically masked plasma patterning of silicon nitride was shown to be capable of forming fine lines on silicon surfaces with spacings between mask and substrate as great as 250 micrometers. Extensive work was performed on advances in plated metallization. The need for the thick electroless palladium layer was eliminated. Further, copper was successfully utilized as a conductor layer utilizing nickel as a barrier to copper diffusion into the silicon. Plasma etching of silicon for texturing and saw damage removal was shown technically feasible but not cost effective compared to wet chemical etching techniques.

Titanium induced polarity inversion in ordered (In,Ga)N/GaN nanocolumns.

PubMed

Kong, X; Li, H; Albert, S; Bengoechea-Encabo, A; Sanchez-Garcia, M A; Calleja, E; Draxl, C; Trampert, A

2016-02-12

We report on the formation of polarity inversion in ordered (In,Ga)N/GaN nanocolumns grown on a Ti-masked GaN-buffered sapphire substrate by plasma assisted molecular beam epitaxy. High-resolution transmission electron microscopy and electron energy-loss spectroscopy reveal a stacking fault-like planar defect at the homoepitaxial GaN interface due to Ti incorporation, triggering the generation of N-polar domains in Ga-polar nanocolumns. Density functional theory calculations are applied to clarify the atomic configurations of a Ti monolayer occupation on the GaN (0002) plane and to prove the inversion effect. The polarity inversion leads to an enhanced indium incorporation in the subsequent (In,Ga)N segment of the nanocolumn. This study provides a deeper understanding of the effects of Ti mask in the well-controlled selective area growth of (In,Ga)N/GaN nanocolumns.

Temperature sensor based on a polymer diffraction grating with silver nanoparticles

NASA Astrophysics Data System (ADS)

Nuzhdin, V. I.; Valeev, V. F.; Galyautdinov, M. F.; Osin, Yu. N.; Stepanov, A. L.

2018-01-01

The method is suggested for producing an optical temperature noncontact sensor on a polymer polymethylmethacrylate (PMMA) substrate with a diffraction optical element formed by implanting low-energy high-dose silver ions through a surface mask. Ion implantation is performed at an energy of 30 keV, a radiation dose of 5.0 × 1016 ion cm-2 and an ion beam current density of 2 μA cm-2 through a surface metal mask having the form of grid with square periodical holes (cells) of size 25 μm. In the course of implantation, silver nanoparticles are produced in periodical unmasked domains of irradiated PMMA. Operation of the temperature sensor on diffraction microstructures made of polymer with silver nanoparticles is demonstrated in the range from 20 °C to 95 °C by testing it with a probe radiation of a He - Ne laser.

Masking the Feeling of Being Stupid.

ERIC Educational Resources Information Center

Smith, Sally L.

1988-01-01

Teaching experience at The Lab School of Washington has shown that learning-disabled children and adults cope with their lack of self-esteem and feelings of stupidity by developing masks to hide their hurt. These include masks of super-competence, helplessness, invisibility, clowning, injustice collecting, indifference, boredom, outrageousness,…

A mathematical framework to quantify the masking effect associated with the confidence intervals of measures of disproportionality

PubMed Central

Maignen, François; Hauben, Manfred; Dogné, Jean-Michel

2017-01-01

Background: The lower bound of the 95% confidence interval of measures of disproportionality (Lower95CI) is widely used in signal detection. Masking is a statistical issue by which true signals of disproportionate reporting are hidden by the presence of other medicines. The primary objective of our study is to develop and validate a mathematical framework for assessing the masking effect of Lower95CI. Methods: We have developed our new algorithm based on the masking ratio (MR) developed for the measures of disproportionality. A MR for the Lower95CI (MRCI) is proposed. A simulation study to validate this algorithm was also conducted. Results: We have established the existence of a very close mathematical relation between MR and MRCI. For a given drug–event pair, the same product will be responsible for the highest masking effect with the measure of disproportionality and its Lower95CI. The extent of masking is likely to be very similar across the two methods. An important proportion of identical drug–event associations affected by the presence of an important masking effect is revealed by the unmasking exercise, whether the proportional reporting ratio (PRR) or its confidence interval are used. Conclusion: The detection of the masking effect of Lower95CI can be automated. The real benefits of this unmasking in terms of new true-positive signals (rate of true-positive/false-positive) or time gained by the revealing of signals using this method have not been fully assessed. These benefits should be demonstrated in the context of prospective studies. PMID:28845231

Performance and stability of mask process correction for EBM-7000

NASA Astrophysics Data System (ADS)

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

2010-05-01

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

Masked Hypertension and Incident Clinic Hypertension Among Blacks in the Jackson Heart Study.

PubMed

Abdalla, Marwah; Booth, John N; Seals, Samantha R; Spruill, Tanya M; Viera, Anthony J; Diaz, Keith M; Sims, Mario; Muntner, Paul; Shimbo, Daichi

2016-07-01

Masked hypertension, defined as nonelevated clinic blood pressure (BP) and elevated out-of-clinic BP may be an intermediary stage in the progression from normotension to hypertension. We examined the associations of out-of-clinic BP and masked hypertension using ambulatory BP monitoring with incident clinic hypertension in the Jackson Heart Study, a prospective cohort of blacks. Analyses included 317 participants with clinic BP <140/90 mm Hg, complete ambulatory BP monitoring, who were not taking antihypertensive medication at baseline in 2000 to 2004. Masked daytime hypertension was defined as mean daytime blood pressure ≥135/85 mm Hg, masked night-time hypertension as mean night-time BP ≥120/70 mm Hg, and masked 24-hour hypertension as mean 24-hour BP ≥130/80 mm Hg. Incident clinic hypertension, assessed at study visits in 2005 to 2008 and 2009 to 2012, was defined as the first visit with clinic systolic/diastolic BP ≥140/90 mm Hg or antihypertensive medication use. During a median follow-up of 8.1 years, there were 187 (59.0%) incident cases of clinic hypertension. Clinic hypertension developed in 79.2% and 42.2% of participants with and without any masked hypertension, 85.7% and 50.4% with and without masked daytime hypertension, 79.9% and 43.7% with and without masked night-time hypertension, and 85.7% and 48.2% with and without masked 24-hour hypertension, respectively. Multivariable-adjusted hazard ratios (95% confidence interval) of incident clinic hypertension for any masked hypertension and masked daytime, night-time, and 24-hour hypertension were 2.13 (1.51-3.02), 1.79 (1.24-2.60), 2.22 (1.58-3.12), and 1.91 (1.32-2.75), respectively. These findings suggest that ambulatory BP monitoring can identify blacks at increased risk for developing clinic hypertension. © 2016 American Heart Association, Inc.

Masked Hypertension and Incident Clinic Hypertension among African Americans in the Jackson Heart Study

PubMed Central

Abdalla, Marwah; Booth, John N.; Seals, Samantha R.; Spruill, Tanya M.; Viera, Anthony J.; Diaz, Keith M.; Sims, Mario; Muntner, Paul; Shimbo, Daichi

2016-01-01

Masked hypertension, defined as non-elevated clinic blood pressure and elevated out-of-clinic blood pressure may be an intermediary stage in the progression from normotension to hypertension. We examined the associations of out-of-clinic blood pressure and masked hypertension using ambulatory blood pressure monitoring with incident clinic hypertension in the Jackson Heart Study, a prospective cohort of African Americans. Analyses included 317 participants with clinic blood pressure <140/90mmHg, complete ABPM, who were not taking antihypertensive medication at baseline in 2000–2004. Masked daytime hypertension was defined as mean daytime blood pressure ≥135/85mmHg; masked nighttime hypertension as mean nighttime blood pressure ≥120/70mmHg; and masked 24-hour hypertension as mean 24-hour blood pressure ≥130/80mmHg. Incident clinic hypertension, assessed at study visits in 2005–2008 and 2009–2012, was defined as the first visit with clinic systolic/diastolic blood pressure ≥140/90mmHg or antihypertensive medication use. During a median follow-up of 8.1 years, there were 187 (59.0%) incident cases of clinic hypertension. Clinic hypertension developed in 79.2% and 42.2% of participants with and without any masked hypertension, 85.7% and 50.4% with and without masked daytime hypertension, 79.9% and 43.7% with and without masked nighttime hypertension and 85.7% and 48.2% with and without masked 24-hour hypertension, respectively. Multivariable-adjusted hazard ratios (95% CI) of incident clinic hypertension for any masked hypertension and masked daytime, nighttime, and 24-hour hypertension were 2.13 (1.51–3.02), 1.79 (1.24–2.60), 2.22 (1.58–3.12), and 1.91 (1.32–2.75), respectively. These findings suggest that ambulatory blood pressure monitoring can identify African Americans at increased risk for developing clinic hypertension. PMID:27185746

Development of techniques for evaluating the physiological protective efficiency of civil aviation oxygen equipment.

DOT National Transportation Integrated Search

1967-04-01

A number of techniques for determining the protective efficiency of passenger and crew masks was developed, utilized and compared. In the case of newly developed passenger masks, subjects were exposed to a chamber flight profile designed around the N...

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

ERIC Educational Resources Information Center

Jones, Angela Thomas

1992-01-01

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

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

ERIC Educational Resources Information Center

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

2018-01-01

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

Designs and Materials for Better Coronagraph Occulting Masks

NASA Technical Reports Server (NTRS)

Balasubramanian, Kunjithapatham

2010-01-01

New designs, and materials appropriate for such designs, are under investigation in an effort to develop coronagraph occulting masks having broad-band spectral characteristics superior to those currently employed. These designs and materials are applicable to all coronagraphs, both ground-based and spaceborne. This effort also offers potential benefits for the development of other optical masks and filters that are required (1) for precisely tailored spatial transmission profiles, (2) to be characterized by optical-density neutrality and phase neutrality (that is, to be characterized by constant optical density and constant phase over broad wavelength ranges), and/or (3) not to exhibit optical- density-dependent phase shifts. The need for this effort arises for the following reasons: Coronagraph occulting masks are required to impose, on beams of light transmitted through them, extremely precise control of amplitude and phase according to carefully designed transmission profiles. In the original application that gave rise to this effort, the concern has been to develop broad-band occulting masks for NASA s Terrestrial Planet Finder coronagraph. Until now, experimental samples of these masks have been made from high-energy-beam-sensitive (HEBS) glass, which becomes locally dark where irradiated with a high-energy electron beam, the amount of darkening depending on the electron-beam energy and dose. Precise mask profiles have been written on HEBS glass blanks by use of electron beams, and the masks have performed satisfactorily in monochromatic light. However, the optical-density and phase profiles of the HEBS masks vary significantly with wavelength; consequently, the HEBS masks perform unsatisfactorily in broad-band light. The key properties of materials to be used in coronagraph occulting masks are their extinction coefficients, their indices of refraction, and the variations of these parameters with wavelength. The effort thus far has included theoretical predictions of performances of masks that would be made from alternative materials chosen because the wavelength dependences of their extinction coefficients and their indices of refraction are such that that the optical-density and phase profiles of masks made from these materials can be expected to vary much less with wavelength than do those of masks made from HEBS glass. The alternative materials considered thus far include some elemental metals such as Pt and Ni, metal alloys such as Inconel, metal nitrides such as TiN, and dielectrics such as SiO2. A mask as now envisioned would include thin metal and dielectric films having stepped or smoothly varying thicknesses (see figure). The thicknesses would be chosen, taking account of the indices of refraction and extinction coefficients, to obtain an acceptably close approximation of the desired spatial transmittance profile with a flat phase profile

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

NASA Astrophysics Data System (ADS)

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

2008-05-01

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

Pattern Laser Annealing by a Pulsed Laser

NASA Astrophysics Data System (ADS)

Komiya, Yoshio; Hoh, Koichiro; Murakami, Koichi; Takahashi, Tetsuo; Tarui, Yasuo

1981-10-01

Preliminary experiments with contact-type pattern laser annealing were made for local polycrystallization of a-Si, local evaporation of a-Si and local formation of Ni-Si alloy. These experiments showed that the mask patterns can be replicated as annealed regions with a resolution of a few microns on substrates. To overcome shortcomings due to the contact type pattern annealing, a projection type reduction pattern laser annealing system is proposed for resistless low temperature pattern forming processes.

Microstructured polymer films by X-ray lithographic exposure and grafting

NASA Astrophysics Data System (ADS)

Gürsel, Selmiye A.; Padeste, Celestino; Solak, Harun H.; Scherer, Günther G.

2005-07-01

Recently we reported on a new technique to generate micro- and nanostructured polymer materials by the combination of selective irradiation of polymer substrates with X-rays and subsequent grafting of a second polymer. Here we focus on the spatially defined grafting throughout the thickness of poly(ethylene-alt-tetrafluoroethylene) (ETFE) and poly (tetrafluoroethylene-co-hexafluoropropylene) (FEP) films using X-ray irradiation through a metal mask, followed by grafting with styrene. Calculations of the transmission of X-rays through the polymer as a function of the wavelength have revealed that energy deposition within the substrate material, which should control the density of created radicals, can be selected in a wide range. Depending on the used wavelength the radicals are created either near the surface or in the bulk of the sample. First experiments demonstrated spatially defined grafting through a 100 μm thick ETFE film and 25 μm thick FEP film. The achieved graft level depends on the irradiation dose as well as on the grafting parameters such as concentration, temperature and time. The precision of structure definition within the film depends on the properties of the X-ray source, the metal mask and the grafting process. The presented process allows controlled grafting through fluoropolymer films with micrometer resolution and local modification of the properties of the films, such as ion conductivity, diffusion of specific molecules or optical properties.

Counteracting Power Analysis Attacks by Masking

NASA Astrophysics Data System (ADS)

Oswald, Elisabeth; Mangard, Stefan

The publication of power analysis attacks [12] has triggered a lot of research activities. On the one hand these activities have been dedicated toward the development of secure and efficient countermeasures. On the other hand also new and improved attacks have been developed. In fact, there has been a continuous arms race between designers of countermeasures and attackers. This chapter provides a brief overview of the state-of-the art in the arms race in the context of a countermeasure called masking. Masking is a popular countermeasure that has been extensively discussed in the scientific community. Numerous articles have been published that explain different types of masking and that analyze weaknesses of this countermeasure.

Advantages, Disadvantages, Indications, Contraindications and Surgical Technique of Laryngeal Airway Mask

PubMed Central

Shekar, Ashim; Balakrishna, Ramdas; Sudarshan, H.; Veena, G. C.; Bhuvaneshwari, S.

2017-01-01

The beauty of the laryngeal mask is that it forms an air tight seal enclosing the larynx rather than plugging the pharynx, and avoid airway obstruction in the oropharynx. The goal of its development was to create an intermediate form of airway management face mask and endotracheal tube. Indication for its use includes any procedure that would normally involve the use of a face mask. The laryngeal mask airway was designed as a new concept in airway management and has been gaining a firm position in anesthetic practice. Despite wide spread use the definitive role of the laryngeal mask airway is yet to be established. In some situations, such as after failed tracheal intubation or in oral surgery its use is controversial. There are several unresolved issues, for example the effect of the laryngeal mask on regurgitation and whether or not cricoids pressure prevents placement of mask. We review the techniques of insertion, details of misplacement, and complications associated with use of the laryngeal mask. We then attempt to clarify the role of laryngeal mask in air way management during anesthesia, discussing the advantages and disadvantages as well as indications and contraindications of its use in oral and maxillofacial surgery. PMID:29349045

Advantages, Disadvantages, Indications, Contraindications and Surgical Technique of Laryngeal Airway Mask.

PubMed

Jannu, Anubhav; Shekar, Ashim; Balakrishna, Ramdas; Sudarshan, H; Veena, G C; Bhuvaneshwari, S

2017-12-01

The beauty of the laryngeal mask is that it forms an air tight seal enclosing the larynx rather than plugging the pharynx, and avoid airway obstruction in the oropharynx. The goal of its development was to create an intermediate form of airway management face mask and endotracheal tube. Indication for its use includes any procedure that would normally involve the use of a face mask. The laryngeal mask airway was designed as a new concept in airway management and has been gaining a firm position in anesthetic practice. Despite wide spread use the definitive role of the laryngeal mask airway is yet to be established. In some situations, such as after failed tracheal intubation or in oral surgery its use is controversial. There are several unresolved issues, for example the effect of the laryngeal mask on regurgitation and whether or not cricoids pressure prevents placement of mask. We review the techniques of insertion, details of misplacement, and complications associated with use of the laryngeal mask. We then attempt to clarify the role of laryngeal mask in air way management during anesthesia, discussing the advantages and disadvantages as well as indications and contraindications of its use in oral and maxillofacial surgery.

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.

High-sensitivity x-ray mask damage studies employing holographic gratings and phase-shifting interferometry

NASA Astrophysics Data System (ADS)

Hansen, Matthew E.; Cerrina, Franco

1994-05-01

A high-sensitivity holographic and interferometric metrology developed at the Center for X- ray Lithography (CXrL) has been employed to investigate in-plane distortions (IPD) produced in x-ray mask materials. This metrology has been applied to characterize damage to x-ray mask materials exposed to synchrotron radiation. X-ray mask damage and accelerated mask damage studies on silicon nitride and silicon carbide were conducted on the Aladdin ES-1 and ES-2 beamline exposure stations, respectively. Accumulated in-plane distortions due to x-ray irradiation were extracted from the incremental interferometric phase maps to yield IPD vs. dose curves for silicon nitride mask blanks. Silicon carbide mask blanks were subjected to accelerated mask damage in the high flux 2 mm X 2 mm beam of the ES-2 exposure station. An accelerated damage study of silicon carbide has shown no in-plane distortion for an accumulated dose of 800 kJ/cm2 with a measurement sensitivity of less than 5 nm.

Development of Personalized Fitting Device With 3-Dimensional Solution for Prevention of NIV Oronasal Mask-Related Pressure Ulcers.

PubMed

Shikama, Maiko; Nakagami, Gojiro; Noguchi, Hiroshi; Mori, Taketoshi; Sanada, Hiromi

2018-05-22

Pressure ulcers related to oronasal masks used with noninvasive ventilation (NIV), along with patient discomfort, occur due to improper fit of the mask. We developed a personalized fitting device using a 3-dimensional (3D) scanning solution to prevent the formation of NIV mask-related pressure ulcers. This study aimed to evaluate the effectiveness of the proposed personalized fitting device. We conducted a randomized crossover experimental study of 20 healthy participants to study the use of this personalized fitting device between the face and an NIV mask designed with 3D solutions. The fitting device was not used under the NIV mask for the control. The outcome measures were the presence of blanchable erythema, standardized redness intensity, discomfort level, and contact pressure. The incidence of blanchable erythema and standardized redness intensity values were significantly lower for subjects who used the fitting device when worn for 30 min ( P < .001). The discomfort levels at the forehead, nasal bridge, and both cheeks, as well as leakage, were significantly reduced as well ( P = .008, P < .001, P = .001, P = .002, P = .001, P = .02, P < .001, P < .001, P < .001). Contact pressure at the nasal bridge, where pressure ulcers most frequently develop, was significantly decreased with the fitting device ( P < .001). Personalized fitting devices that incorporate 3D scanning solutions may contribute to the prevention of NIV mask-related pressure ulcers and the reduction of discomfort. Copyright © 2018 by Daedalus Enterprises.

Effectiveness of surgical masks against influenza bioaerosols.

PubMed

Makison Booth, C; Clayton, M; Crook, B; Gawn, J M

2013-05-01

Most surgical masks are not certified for use as respiratory protective devices (RPDs). In the event of an influenza pandemic, logistical and practical implications such as storage and fit testing will restrict the use of RPDs to certain high-risk procedures that are likely to generate large amounts of infectious bioaerosols. Studies have shown that in such circumstances increased numbers of surgical masks are worn, but the protection afforded to the wearer by a surgical mask against infectious aerosols is not well understood. To develop and apply a method for assessing the protection afforded by surgical masks against a bioaerosol challenge. A dummy test head attached to a breathing simulator was used to test the performance of surgical masks against a viral challenge. Several designs of surgical masks commonly used in the UK healthcare sector were evaluated by measuring levels of inert particles and live aerosolised influenza virus in the air, from in front of and behind each mask. Live influenza virus was measurable from the air behind all surgical masks tested. The data indicate that a surgical mask will reduce exposure to aerosolised infectious influenza virus; reductions ranged from 1.1- to 55-fold (average 6-fold), depending on the design of the mask. We describe a workable method to evaluate the protective efficacy of surgical masks and RPDs against a relevant aerosolised biological challenge. The results demonstrated limitations of surgical masks in this context, although they are to some extent protective. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2010-09-01

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

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

NASA Astrophysics Data System (ADS)

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

2007-10-01

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

Bubble masks for time-encoded imaging of fast neutrons.

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

Brubaker, Erik; Brennan, James S.; Marleau, Peter

2013-09-01

Time-encoded imaging is an approach to directional radiation detection that is being developed at SNL with a focus on fast neutron directional detection. In this technique, a time modulation of a detected neutron signal is inducedtypically, a moving mask that attenuates neutrons with a time structure that depends on the source position. An important challenge in time-encoded imaging is to develop high-resolution two-dimensional imaging capabilities; building a mechanically moving high-resolution mask presents challenges both theoretical and technical. We have investigated an alternative to mechanical masks that replaces the solid mask with a liquid such as mineral oil. Instead of fixedmore » blocks of solid material that move in pre-defined patterns, the oil is contained in tubing structures, and carefully introduced air gapsbubblespropagate through the tubing, generating moving patterns of oil mask elements and air apertures. Compared to current moving-mask techniques, the bubble mask is simple, since mechanical motion is replaced by gravity-driven bubble propagation; it is flexible, since arbitrary bubble patterns can be generated by a software-controlled valve actuator; and it is potentially high performance, since the tubing and bubble size can be tuned for high-resolution imaging requirements. We have built and tested various single-tube mask elements, and will present results on bubble introduction and propagation as a function of tubing size and cross-sectional shape; real-time bubble position tracking; neutron source imaging tests; and reconstruction techniques demonstrated on simple test data as well as a simulated full detector system.« less

Innovative Masking of Ferrous Inserts in Magnesium Aerospace Components Prior to Tagnite Anodization (v.1, Unlimited Release)

DTIC Science & Technology

2013-07-01

cadmium plating, and other metals cannot be anodized. If any of these dissimilar metals are in contact with the Tagnite electrolyte during the...commercial masking vendor had to offer. TAG contacted Acme Masking Company, Avon, Indiana , who specializes in developing masking for aluminum...were received from TAG. For the purpose of this discussion, the edge of the panel near a hole is considered a top. Each panel had a cadmium -plated

Silicon micro-mold and method for fabrication

DOEpatents

Morales, Alfredo M.

2005-01-11

The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon micro-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

Silicon micro-mold

DOEpatents

Morales, Alfredo M [Livermore, CA

2006-10-24

The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

Manufacture of a conformal multilayer rf antenna substrate using excimer mask imaging technology and a 6-axis robot

NASA Astrophysics Data System (ADS)

Charrier, Michel; Everett, Daniel; Fieret, Jim; Karrer, Tobias; Rau, Sven; Valard, Jean-Luc

2001-06-01

A novel method is presented to produce a high precision pattern of copper tracks on both sides of a 4-layer conformal radar antenna made of PEI polymer and shaped as a truncated pseudo-parabolic cylinder. The antenna is an active emitter-receiver so that an accuracy of a fraction of the wavelength of the microwave radiation is required. After 2D layer design in Allegro, the resulting Gerber file-format circuits are wrapped around the antenna shape, resulting in a cutter-path file which provides the input for a postprocessor that outputs G-code for robot- and laser control. A rules file contains embedded information such as laser parameters and mask aperture related to the Allegro symbols. The robot consists of 6 axes that manipulate the antenna, and 2 axes for the mask plate. The antenna can be manipulated to an accuracy of +/- 20 micrometers over its full dimensions of 200x300x50 mm. The four layers are constructed by successive copper coating, resist coating, laser ablation, copper etching, resist removal, insulation polyimide film lamination and laser dielectric drilling for microvia holes and through-holes drilling. Applications are in space and aeronautical communication and radar detection systems, with possible extensions to automotive and mobile hand-sets, and land stations.

Stretchable multilayer self-aligned interconnects fabricated using excimer laser photoablation and in situ masking

NASA Astrophysics Data System (ADS)

Lin, Kevin L.; Jain, Kanti

2009-02-01

Stretchable interconnects are essential to large-area flexible circuits and large-area sensor array systems, and they play an important role towards the realization of the realm of systems which include wearable electronics, sensor arrays for structural health monitoring, and sensor skins for tactile feedback. These interconnects must be reliable and robust for viability, and must be flexible, stretchable, and conformable to non-planar surfaces. This research describes the design, modeling, fabrication, and testing of stretchable interconnects on polymer substrates using metal patterns both as functional interconnect layers and as in-situ masks for excimer laser photoablation. Excimer laser photoablation is often used for patterning of polymers and thin-film metals. The fluences for photoablation of polymers are generally much lower than the threshold fluence for removal or damage of high-thermallyconductive metals; thus, metal thin films can be used as in-situ masks for polymers if the proper fluence is used. Selfaligned single-layer and multi-layer interconnects of various designs (rectilinear and 'meandering') have been fabricated, and certain 'meandering' interconnect designs can be stretched up to 50% uniaxially while maintaining good electrical conductivity and structural integrity. These results are compared with Finite Element Analysis (FEA) models and are observed to be in good accordance with them. This fabrication approach eliminates masks and microfabrication processing steps as compared to traditional fabrication approaches; furthermore, this technology is scalable for large-area sensor arrays and electronic circuits, adaptable for a variety of materials and interconnects designs, and compatible with MEMS-based capacitive sensor technology.

Regional brain activity during early visual perception in unaffected siblings of schizophrenia patients.

PubMed

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

2010-07-01

Visual masking paradigms assess the early part of visual information processing, which may reflect vulnerability measures for schizophrenia. We examined the neural substrates of visual backward performance in unaffected sibling of schizophrenia patients using functional magnetic resonance imaging (fMRI). Twenty-one unaffected siblings of schizophrenia patients and 19 healthy controls performed a backward masking task and three functional localizer tasks to identify three visual processing regions of interest (ROI): lateral occipital complex (LO), the motion-sensitive area, and retinotopic areas. In the masking task, we systematically manipulated stimulus onset asynchronies (SOAs). We analyzed fMRI data in two complementary ways: 1) an ROI approach for three visual areas, and 2) a whole-brain analysis. The groups did not differ in behavioral performance. For ROI analysis, both groups increased activation as SOAs increased in LO. Groups did not differ in activation levels of the three ROIs. For whole-brain analysis, controls increased activation as a function of SOAs, compared with siblings in several regions (i.e., anterior cingulate cortex, posterior cingulate cortex, inferior prefrontal cortex, inferior parietal lobule). The study found: 1) area LO showed sensitivity to the masking effect in both groups; 2) siblings did not differ from controls in activation of LO; and 3) groups differed significantly in several brain regions outside visual processing areas that have been related to attentional or re-entrant processes. These findings suggest that LO dysfunction may be a disease indicator rather than a risk indicator for schizophrenia. Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Simulation-based MDP verification for leading-edge masks

NASA Astrophysics Data System (ADS)

Su, Bo; Syrel, Oleg; Pomerantsev, Michael; Hagiwara, Kazuyuki; Pearman, Ryan; Pang, Leo; Fujimara, Aki

2017-07-01

For IC design starts below the 20nm technology node, the assist features on photomasks shrink well below 60nm and the printed patterns of those features on masks written by VSB eBeam writers start to show a large deviation from the mask designs. Traditional geometry-based fracturing starts to show large errors for those small features. As a result, other mask data preparation (MDP) methods have become available and adopted, such as rule-based Mask Process Correction (MPC), model-based MPC and eventually model-based MDP. The new MDP methods may place shot edges slightly differently from target to compensate for mask process effects, so that the final patterns on a mask are much closer to the design (which can be viewed as the ideal mask), especially for those assist features. Such an alteration generally produces better masks that are closer to the intended mask design. Traditional XOR-based MDP verification cannot detect problems caused by eBeam effects. Much like model-based OPC verification which became a necessity for OPC a decade ago, we see the same trend in MDP today. Simulation-based MDP verification solution requires a GPU-accelerated computational geometry engine with simulation capabilities. To have a meaningful simulation-based mask check, a good mask process model is needed. The TrueModel® system is a field tested physical mask model developed by D2S. The GPU-accelerated D2S Computational Design Platform (CDP) is used to run simulation-based mask check, as well as model-based MDP. In addition to simulation-based checks such as mask EPE or dose margin, geometry-based rules are also available to detect quality issues such as slivers or CD splits. Dose margin related hotspots can also be detected by setting a correct detection threshold. In this paper, we will demonstrate GPU-acceleration for geometry processing, and give examples of mask check results and performance data. GPU-acceleration is necessary to make simulation-based mask MDP verification acceptable.

All dispenser printed flexible 3D structured thermoelectric generators

NASA Astrophysics Data System (ADS)

Cao, Z.; Shi, J. J.; Torah, R. N.; Tudor, M. J.; Beeby, S. P.

2015-12-01

This work presents a vertically fabricated 3D thermoelectric generator (TEG) by dispenser printing on flexible polyimide substrate. This direct-write technology only involves printing of electrodes, thermoelectric active materials and structure material, which needs no masks to transfer the patterns onto the substrate. The dimension for single thermoelectric element is 2 mm × 2 mm × 0.5 mm while the distance between adjacent cubes is 1.2 mm. The polymer structure layer was used to support the electrodes which are printed to connect the top ends of the thermoelectric material and ensure the flexibility as well. The advantages and the limitations of the dispenser printed 3D TEGs will also be evaluated in this paper. The proposed method is potential to be a low-cost and scalable fabrication solution for TEGs.

Solvothermal Vapor Annealing of Lamellar Poly(styrene)-block-poly(d,l-lactide) Block Copolymer Thin Films for Directed Self-Assembly Application.

PubMed

Cummins, Cian; Mokarian-Tabari, Parvaneh; Andreazza, Pascal; Sinturel, Christophe; Morris, Michael A

2016-03-01

Solvothermal vapor annealing (STVA) was employed to induce microphase separation in a lamellar forming block copolymer (BCP) thin film containing a readily degradable block. Directed self-assembly of poly(styrene)-block-poly(d,l-lactide) (PS-b-PLA) BCP films using topographically patterned silicon nitride was demonstrated with alignment over macroscopic areas. Interestingly, we observed lamellar patterns aligned parallel as well as perpendicular (perpendicular microdomains to substrate in both cases) to the topography of the graphoepitaxial guiding patterns. PS-b-PLA BCP microphase separated with a high degree of order in an atmosphere of tetrahydrofuran (THF) at an elevated vapor pressure (at approximately 40-60 °C). Grazing incidence small-angle X-ray scattering (GISAXS) measurements of PS-b-PLA films reveal the through-film uniformity of perpendicular microdomains after STVA. Perpendicular lamellar orientation was observed on both hydrophilic and relatively hydrophobic surfaces with a domain spacing (L0) of ∼32.5 nm. The rapid removal of the PLA microdomains is demonstrated using a mild basic solution for the development of a well-defined PS mask template. GISAXS data reveal the through-film uniformity is retained following wet etching. The experimental results in this article demonstrate highly oriented PS-b-PLA microdomains after a short annealing period and facile PLA removal to form porous on-chip etch masks for nanolithography application.

Improvement of optical quality of semipolar (11 2 ¯ 2 ) GaN on m-plane sapphire by in-situ epitaxial lateral overgrowth

NASA Astrophysics Data System (ADS)

Monavarian, Morteza; Izyumskaya, Natalia; Müller, Marcus; Metzner, Sebastian; Veit, Peter; Can, Nuri; Das, Saikat; Özgür, Ümit; Bertram, Frank; Christen, Jürgen; Morkoç, Hadis; Avrutin, Vitaliy

2016-04-01

Among the major obstacles for development of non-polar and semipolar GaN structures on foreign substrates are stacking faults which deteriorate the structural and optical quality of the material. In this work, an in-situ SiNx nano-network has been employed to achieve high quality heteroepitaxial semipolar (11 2 ¯ 2 ) GaN on m-plane sapphire with reduced stacking fault density. This approach involves in-situ deposition of a porous SiNx interlayer on GaN that serves as a nano-mask for the subsequent growth, which starts in the nanometer-sized pores (window regions) and then progresses laterally as well, as in the case of conventional epitaxial lateral overgrowth (ELO). The inserted SiNx nano-mask effectively prevents the propagation of defects, such as dislocations and stacking faults, in the growth direction and thus reduces their density in the overgrown layers. The resulting semipolar (11 2 ¯ 2 ) GaN layers exhibit relatively smooth surface morphology and improved optical properties (PL intensity enhanced by a factor of 5 and carrier lifetimes by 35% to 85% compared to the reference semipolar (11 2 ¯ 2 ) GaN layer) which approach to those of the c-plane in-situ nano-ELO GaN reference and, therefore, holds promise for light emitting and detecting devices.

Realization and Integration of Large Lattice Mismatched Materials for Device Innovation: A Comprehensive Approach to the Underlying Science and Practical Application

DTIC Science & Technology

2011-07-08

Nastasi. Effects of Hydrogen Implantation Conditions on the Trapping of Hydrogen in InP, Applied Physics Letters ( ) 2006/07/25 10:01:57 1 TOTAL: 6...formation of 20 nm PMMA cylinder in a matrix of polystyrene. This cylinder pattern can be transferred to an underlying dielectric mask and used in...allowing for selective hydrogen implantation . The implanted wafers were bonded to acceptor substrates and transfer was initiated. The surface of the

Design and Fabrication of a Strain-Powered Microelectromechanical System (MEMS) Switch

DTIC Science & Technology

2014-09-01

release showing uniform folding upwards; the top edge appears to be anchored to the substrate, which necessitated a mask rewrite after reducing...underdeveloped resist causing the switch to be anchored (left), thin-film shearing at the contact edge (right), and thin- film edge anchoring (right). Geometry...a “hip” joint and an “ ankle ” joint—while a center hinge was designed to fold down at a “knee” joint and make electrical contact with an electrical

Automated imprint mask cleaning for step-and-flash imprint lithography

NASA Astrophysics Data System (ADS)

Singh, Sherjang; Chen, Ssuwei; Selinidis, Kosta; Fletcher, Brian; McMackin, Ian; Thompson, Ecron; Resnick, Douglas J.; Dress, Peter; Dietze, Uwe

2009-03-01

Step-and-Flash Imprint Lithography (S-FIL) is a promising lithography strategy for semiconductor manufacturing at device nodes below 32nm. The S-FIL 1:1 pattern transfer technology utilizes a field-by-field ink jet dispense of a low viscosity liquid resist to fill the relief pattern of the device layer etched into the glass mask. Compared to other sub 40nm CD lithography methods, the resulting high resolution, high throughput through clustering, 3D patterning capability, low process complexity, and low cost of ownership (CoO) of S-FIL makes it a widely accepted technology for patterned media as well as a promising mainstream option for future CMOS applications. Preservation of mask cleanliness is essential to avoid risk of repeated printing of defects. The development of mask cleaning processes capable of removing particles adhered to the mask surface without damaging the mask is critical to meet high volume manufacturing requirements. In this paper we have presented various methods of residual (cross-linked) resist removal and final imprint mask cleaning demonstrated on the HamaTech MaskTrack automated mask cleaning system. Conventional and non-conventional (acid free) methods of particle removal have been compared and the effect of mask cleaning on pattern damage and CD integrity is also studied.

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

NASA Astrophysics Data System (ADS)

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

2004-05-01

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

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

NASA Astrophysics Data System (ADS)

Hosono, Kunihiro; Kato, Kokoro

2008-10-01

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

Structural basis of redox-dependent substrate binding of protein disulfide isomerase

PubMed Central

Yagi-Utsumi, Maho; Satoh, Tadashi; Kato, Koichi

2015-01-01

Protein disulfide isomerase (PDI) is a multidomain enzyme, operating as an essential folding catalyst, in which the b′ and a′ domains provide substrate binding sites and undergo an open–closed domain rearrangement depending on the redox states of the a′ domain. Despite the long research history of this enzyme, three-dimensional structural data remain unavailable for its ligand-binding mode. Here we characterize PDI substrate recognition using α-synuclein (αSN) as the model ligand. Our nuclear magnetic resonance (NMR) data revealed that the substrate-binding domains of PDI captured the αSN segment Val37–Val40 only in the oxidized form. Furthermore, we determined the crystal structure of an oxidized form of the b′–a′ domains in complex with an undecapeptide corresponding to this segment. The peptide-binding mode observed in the crystal structure with NMR validation, was characterized by hydrophobic interactions on the b′ domain in an open conformation. Comparison with the previously reported crystal structure indicates that the a′ domain partially masks the binding surface of the b′ domain, causing steric hindrance against the peptide in the reduced form of the b′–a′ domains that exhibits a closed conformation. These findings provide a structural basis for the mechanism underlying the redox-dependent substrate binding of PDI. PMID:26350503

Sub-100 nm gold nanohole-enhanced Raman scattering on flexible PDMS sheets.

PubMed

Lee, Seunghyun; Ongko, Andry; Kim, Ho Young; Yim, Sang-Gu; Jeon, Geumhye; Jeong, Hee Jin; Lee, Seungwoo; Kwak, Minseok; Yang, Seung Yun

2016-08-05

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive vibrational spectroscopy technique enabling detection of multiple analytes at the molecular level in a nondestructive and rapid manner. In this work, we introduce a new approach to fabricate deep subwavelength-scaled (sub-100 nm) metallic nanohole arrays (quasi-3D metallic nanoholes) on flexible and highly efficient SERS substrates. Target structures have been fabricated using a two-step process consisting of (i) direct pattern transfer of spin-coated polymer films onto polydimethylsiloxane (PDMS) substrates by plasma etching with transferred anodic aluminum oxide masks, and (ii) producing SERS-active substrates by functionalization of the etched polymeric films followed by Au deposition. Such an all-dry, top-down lithographic approach enables on-demand patterning of SERS-active metallic nanoholes with high structural fidelity even onto flexible and stretchable substrates, thus making possible multiple sensing modes in a versatile fashion. For example, metallic nanoholes on flexible PDMS substrates are highly amenable to their integration with curved glass sticks, which can be used in optical fiber-integrated SERS systems. Au surfaces immobilized by probe DNA molecules show a selective enhancement of Raman scattering with Cy5-labeled complementary DNA (as compared to flat Au surfaces), demonstrating the potential of using the quasi-3D Au nanohole arrays for bio-sensing applications.

Sub-100 nm gold nanohole-enhanced Raman scattering on flexible PDMS sheets

NASA Astrophysics Data System (ADS)

Lee, Seunghyun; Ongko, Andry; Kim, Ho Young; Yim, Sang-Gu; Jeon, Geumhye; Jeong, Hee Jin; Lee, Seungwoo; Kwak, Minseok; Yang, Seung Yun

2016-08-01

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive vibrational spectroscopy technique enabling detection of multiple analytes at the molecular level in a nondestructive and rapid manner. In this work, we introduce a new approach to fabricate deep subwavelength-scaled (sub-100 nm) metallic nanohole arrays (quasi-3D metallic nanoholes) on flexible and highly efficient SERS substrates. Target structures have been fabricated using a two-step process consisting of (i) direct pattern transfer of spin-coated polymer films onto polydimethylsiloxane (PDMS) substrates by plasma etching with transferred anodic aluminum oxide masks, and (ii) producing SERS-active substrates by functionalization of the etched polymeric films followed by Au deposition. Such an all-dry, top-down lithographic approach enables on-demand patterning of SERS-active metallic nanoholes with high structural fidelity even onto flexible and stretchable substrates, thus making possible multiple sensing modes in a versatile fashion. For example, metallic nanoholes on flexible PDMS substrates are highly amenable to their integration with curved glass sticks, which can be used in optical fiber-integrated SERS systems. Au surfaces immobilized by probe DNA molecules show a selective enhancement of Raman scattering with Cy5-labeled complementary DNA (as compared to flat Au surfaces), demonstrating the potential of using the quasi-3D Au nanohole arrays for bio-sensing applications.

Computerized Dead-Space Volume Measurement of Face Masks Applied to Simulated Faces.

PubMed

Amirav, Israel; Luder, Anthony S; Halamish, Asaf; Marzuk, Chatib; Daitzchman, Marcelo; Newhouse, Michael T

2015-09-01

The dead-space volume (VD) of face masks for metered-dose inhaler treatments is particularly important in infants and young children with asthma, who have relatively low tidal volumes. Data about VD have been traditionally obtained from water displacement measurements, in which masks are held against a flat surface. Because, in real life, masks are placed against the face, VD is likely to differ considerably between masks depending upon their contour and fit. The aim of this study was to develop an accurate and reliable way to measure VD electronically and to apply this technique by comparing the electronic VD of commonly available face masks. Average digital faces were obtained from 3-dimensional images of 270 infants and children. Commonly used face masks (small and medium) from various manufacturers (Monaghan Medical, Pari Respiratory Equipment, Philips Respironics, and InspiRx) were scanned and digitized by means of computed tomography. Each mask was electronically applied to its respective digital face, and the VD enclosed (mL) was computerized and precisely measured. VD varied between 22.6 mL (SootherMask, InspiRx) and 43.1 mL (Vortex, Pari) for small masks and between 41.7 mL (SootherMask) and 71.5 mL (AeroChamber, Monaghan Medical) for medium masks. These values were significantly lower and less variable than measurements obtained by water displacement. Computerized techniques provide an innovative and relatively simple way of accurately measuring the VD of face masks applied to digital faces. As determined by computerized measurement using average-size virtual faces, the InspiRx masks had a significantly smaller VD for both small and medium masks compared with the other masks. This is of considerable importance with respect to aerosol dose and delivery time, particularly in young children. (ClinicalTrials.gov registration NCT01274299.). Copyright © 2015 by Daedalus Enterprises.

Understanding and reduction of defects on finished EUV masks

NASA Astrophysics Data System (ADS)

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

2005-05-01

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

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.

Implementation on Landsat Data of a Simple Cloud Mask Algorithm Developed for MODIS Land Bands

NASA Technical Reports Server (NTRS)

Oreopoulos, Lazaros; Wilson, Michael J.; Varnai, Tamas

2010-01-01

This letter assesses the performance on Landsat-7 images of a modified version of a cloud masking algorithm originally developed for clear-sky compositing of Moderate Resolution Imaging Spectroradiometer (MODIS) images at northern mid-latitudes. While data from recent Landsat missions include measurements at thermal wavelengths, and such measurements are also planned for the next mission, thermal tests are not included in the suggested algorithm in its present form to maintain greater versatility and ease of use. To evaluate the masking algorithm we take advantage of the availability of manual (visual) cloud masks developed at USGS for the collection of Landsat scenes used here. As part of our evaluation we also include the Automated Cloud Cover Assesment (ACCA) algorithm that includes thermal tests and is used operationally by the Landsat-7 mission to provide scene cloud fractions, but no cloud masks. We show that the suggested algorithm can perform about as well as ACCA both in terms of scene cloud fraction and pixel-level cloud identification. Specifically, we find that the algorithm gives an error of 1.3% for the scene cloud fraction of 156 scenes, and a root mean square error of 7.2%, while it agrees with the manual mask for 93% of the pixels, figures very similar to those from ACCA (1.2%, 7.1%, 93.7%).

A direct-measurement technique for estimating discharge-chamber lifetime. [for ion thrusters

NASA Technical Reports Server (NTRS)

Beattie, J. R.; Garvin, H. L.

1982-01-01

The use of short-term measurement techniques for predicting the wearout of ion thrusters resulting from sputter-erosion damage is investigated. The laminar-thin-film technique is found to provide high precision erosion-rate data, although the erosion rates are generally substantially higher than those found during long-term erosion tests, so that the results must be interpreted in a relative sense. A technique for obtaining absolute measurements is developed using a masked-substrate arrangement. This new technique provides a means for estimating the lifetimes of critical discharge-chamber components based on direct measurements of sputter-erosion depths obtained during short-duration (approximately 1 hr) tests. Results obtained using the direct-measurement technique are shown to agree with sputter-erosion depths calculated for the plasma conditions of the test. The direct-measurement approach is found to be applicable to both mercury and argon discharge-plasma environments and will be useful for estimating the lifetimes of inert gas and extended performance mercury ion thrusters currently under development.

Fabrication of a Polymer Micro Needle Array by Mask-Dragging X-Ray Lithography and Alignment X-Ray Lithography

NASA Astrophysics Data System (ADS)

Li, Yi-Gui; Yang, Chun-Sheng; Liu, Jing-Quan; Sugiyama, Susumu

2011-03-01

Polymer materials such as transparent thermoplastic poly(methyl methacrylate) (PMMA) have been of great interest in the research and development of integrated circuits and micro-electromechanical systems due to their relatively low cost and easy process. We fabricated PMMA-based polymer hollow microneedle arrays by mask-dragging and aligning x-ray lithography. Techniques for 3D micromachining by direct lithography using x-rays are developed. These techniques are based on using image projection in which the x-ray is used to illuminate an appropriate gold pattern on a polyimide film mask. The mask is imaged onto the PMMA sample. A pattern with an area of up to 100 × 100mm2 can be fabricated with sub-micron resolution and a highly accurate order of a few microns by using a dragging mask. The fabrication technology has several advantages, such as forming complex 3D micro structures, high throughput and low cost.

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

NASA Astrophysics Data System (ADS)

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

2015-07-01

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

Disentangling the Developmental Trajectories of Letter Position and Letter Identity Coding Using Masked Priming

ERIC Educational Resources Information Center

Kezilas, Yvette; McKague, Meredith; Kohnen, Saskia; Badcock, Nicholas A.; Castles, Anne

2017-01-01

Masked transposed-letter (TL) priming effects have been used to index letter position processing over the course of reading development. Whereas some studies have reported an increase in TL priming over development, others have reported a decrease. These findings have led to the development of 2 somewhat contradictory accounts of letter position…

Pixel-based OPC optimization based on conjugate gradients.

PubMed

Ma, Xu; Arce, Gonzalo R

2011-01-31

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

Ultraviolet-assisted direct patterning and low-temperature formation of flexible ZrO2 resistive switching arrays on PET/ITO substrates

NASA Astrophysics Data System (ADS)

Li, Lingwei; Chen, Yuanqing; Yin, Xiaoru; Song, Yang; Li, Na; Niu, Jinfen; Wu, Huimin; Qu, Wenwen

2017-12-01

We demonstrate a low-cost and facile photochemical solution method to prepare the ZrO2 resistive switching arrays as memristive units on flexible PET/ITO substrates. ZrO2 solution sensitive to UV light of 337 nm was synthesized using zirconium n-butyl alcohol as the precursor, and benzoylacetone as the complexing agent. After the dip-coated ZrO2 gel films were irradiated through a mask under the UV lamp (with wavelength of 325-365 nm) at room temperature and rinsed in ethanol, the ZrO2 gel arrays were obtained on PET/ITO substrates. Subsequently, the ZrO2 gel arrays were irradiated by deep UV light of 254 and 185 nm at 150 °C, resulting in the amorphous ZrO2 memristive micro-arrays. The ZrO2 units on flexible PET/ITO substrates exhibited excellent memristive properties. A high ratio of 104 of on-state and off-state resistance was obtained. The resistive switching behavior of the flexible device remained stable after being bent for 103 times. The device showed stable flexibility up to a minimum bending diameter of 1.25 cm.

Method for validating cloud mask obtained from satellite measurements using ground-based sky camera.

PubMed

Letu, Husi; Nagao, Takashi M; Nakajima, Takashi Y; Matsumae, Yoshiaki

2014-11-01

Error propagation in Earth's atmospheric, oceanic, and land surface parameters of the satellite products caused by misclassification of the cloud mask is a critical issue for improving the accuracy of satellite products. Thus, characterizing the accuracy of the cloud mask is important for investigating the influence of the cloud mask on satellite products. In this study, we proposed a method for validating multiwavelength satellite data derived cloud masks using ground-based sky camera (GSC) data. First, a cloud cover algorithm for GSC data has been developed using sky index and bright index. Then, Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data derived cloud masks by two cloud-screening algorithms (i.e., MOD35 and CLAUDIA) were validated using the GSC cloud mask. The results indicate that MOD35 is likely to classify ambiguous pixels as "cloudy," whereas CLAUDIA is likely to classify them as "clear." Furthermore, the influence of error propagations caused by misclassification of the MOD35 and CLAUDIA cloud masks on MODIS derived reflectance, brightness temperature, and normalized difference vegetation index (NDVI) in clear and cloudy pixels was investigated using sky camera data. It shows that the influence of the error propagation by the MOD35 cloud mask on the MODIS derived monthly mean reflectance, brightness temperature, and NDVI for clear pixels is significantly smaller than for the CLAUDIA cloud mask; the influence of the error propagation by the CLAUDIA cloud mask on MODIS derived monthly mean cloud products for cloudy pixels is significantly smaller than that by the MOD35 cloud mask.

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

NASA Astrophysics Data System (ADS)

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

2006-06-01

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

Migration from full-head mask to "open-face" mask for immobilization of patients with head and neck cancer.

PubMed

Li, Guang; Lovelock, D Michael; Mechalakos, James; Rao, Shyam; Della-Biancia, Cesar; Amols, Howard; Lee, Nancy

2013-09-06

To provide an alternative device for immobilization of the head while easing claustrophobia and improving comfort, an "open-face" thermoplastic mask was evaluated using video-based optical surface imaging (OSI) and kilovoltage (kV) X-ray radiography. A three-point thermoplastic head mask with a precut opening and reinforced strips was developed. After molding, it provided sufficient visible facial area as the region of interest for OSI. Using real-time OSI, the head motion of ten volunteers in the new mask was evaluated during mask locking and 15minutes lying on the treatment couch. Using a nose mark with reference to room lasers, forced head movement in open-face and full-head masks (with a nose hole) was compared. Five patients with claustrophobia were immobilized with open-face masks, set up using OSI and kV, and treated in 121 fractions, in which 61 fractions were monitored during treatment using real-time OSI. With the open-face mask, head motion was found to be 1.0 ± 0.6 mm and 0.4° ± 0.2° in volunteers during the experiment, and 0.8 ± 0.3 mm and 0.4° ± 0.2° in patients during treatment. These agree with patient motion calculated from pre-/post-treatment OSI and kV data using different anatomical landmarks. In volunteers, the head shift induced by mask-locking was 2.3 ± 1.7 mm and 1.8° ± 0.6°, and the range of forced movements in the open-face and full-head masks were found to be similar. Most (80%) of the volunteers preferred the open-face mask to the full-head mask, while claustrophobic patients could only tolerate the open-face mask. The open-face mask is characterized for its immobilization capability and can immobilize patients sufficiently (< 2 mm) during radiotherapy. It provides a clinical solution to the immobilization of patients with head and neck (HN) cancer undergoing radiotherapy, and is particularly beneficial for claustrophobic patients. This new open-face mask is readily adopted in radiotherapy clinic as a superior alternative to the standard full-head mask.

Data sharing system for lithography APC

NASA Astrophysics Data System (ADS)

Kawamura, Eiichi; Teranishi, Yoshiharu; Shimabara, Masanori

2007-03-01

We have developed a simple and cost-effective data sharing system between fabs for lithography advanced process control (APC). Lithography APC requires process flow, inter-layer information, history information, mask information and so on. So, inter-APC data sharing system has become necessary when lots are to be processed in multiple fabs (usually two fabs). The development cost and maintenance cost also have to be taken into account. The system handles minimum information necessary to make trend prediction for the lots. Three types of data have to be shared for precise trend prediction. First one is device information of the lots, e.g., process flow of the device and inter-layer information. Second one is mask information from mask suppliers, e.g., pattern characteristics and pattern widths. Last one is history data of the lots. Device information is electronic file and easy to handle. The electronic file is common between APCs and uploaded into the database. As for mask information sharing, mask information described in common format is obtained via Wide Area Network (WAN) from mask-vender will be stored in the mask-information data server. This information is periodically transferred to one specific lithography-APC server and compiled into the database. This lithography-APC server periodically delivers the mask-information to every other lithography-APC server. Process-history data sharing system mainly consists of function of delivering process-history data. In shipping production lots to another fab, the product-related process-history data is delivered by the lithography-APC server from the shipping site. We have confirmed the function and effectiveness of data sharing systems.

Rat Palatability Study for Taste Assessment of Caffeine Citrate Formulation Prepared via Hot-Melt Extrusion Technology

PubMed Central

Tiwari, Roshan V.; Polk, Ashley N.; Patil, Hemlata; Ye, Xingyou; Pimparade, Manjeet B.; Repka, Michael A.

2017-01-01

Developing a pediatric oral formulation with an age-appropriate dosage form and taste masking of naturally bitter active pharmaceutical ingredients (APIs) are key challenges for formulation scientists. Several techniques are used for taste masking of bitter APIs to improve formulation palatability; however, not all the techniques are applicable to pediatric dosage forms because of the limitations on the kind and concentration of the excipients that can be used. Hot-melt extrusion (HME) technology is used successfully for taste masking of bitter APIs, and overcomes some of the limitations of the existing taste masking techniques. Likewise, analytical taste assessment is an important quality control parameter evaluated by several in vivo and in vitro methods, such as the human taste panel, electrophysiological methods, electronic sensor, and animal preference tests to aid in selecting a taste-masked formulation. However, the most appropriate in-vivo method to assess the taste-masking efficacy of pediatric formulations remains unknown, because it is not known to what extent the human taste panel/electronic tongue can predict the palatability in the pediatric patients. The purpose of this study was to develop taste-masked caffeine citrate extrudates via HME, and to demonstrate the wide applicability of a single bottle-test rat model to record and compare the volume consumed of the taste-masked solutions to that of the pure API. Thus, this rat model can be considered as a low-cost alternative taste-assessment method to the most commonly used expensive human taste panel/electronic tongue method for pediatric formulations. PMID:26573158

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

NASA Astrophysics Data System (ADS)

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

2015-03-01

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

Temporal masking of multidimensional tactual stimuli

NASA Astrophysics Data System (ADS)

Tan, Hong Z.; Reed, Charlotte M.; Delhorne, Lorraine A.; Durlach, Nathaniel I.; Wan, Natasha

2003-12-01

Experiments were performed to examine the temporal masking properties of multidimensional tactual stimulation patterns delivered to the left index finger. The stimuli consisted of fixed-frequency sinusoidal motions in the kinesthetic (2 or 4 Hz), midfrequency (30 Hz), and cutaneous (300 Hz) frequency ranges. Seven stimuli composed of one, two, or three spectral components were constructed at each of two signal durations (125 or 250 ms). Subjects identified target signals under three different masking paradigms: forward masking, backward masking, and sandwiched masking (in which the target is presented between two maskers). Target identification was studied as a function of interstimulus interval (ISI) in the range 0 to 640 ms. For both signal durations, percent-correct scores increased with ISI for each of the three masking paradigms. Scores with forward and backward masking were similar and significantly higher than scores obtained with sandwiched masking. Analyses of error trials revealed that subjects showed a tendency to respond, more often than chance, with the masker, the composite of the masker and target, or the combination of the target and a component of the masker. The current results are compared to those obtained in previous studies of tactual recognition masking with brief cutaneous spatial patterns. The results are also discussed in terms of estimates of information transfer (IT) and IT rate, are compared to previous studies with multidimensional tactual signals, and are related to research on the development of tactual aids for the deaf.

Precision drilling of fused silica with 157-nm excimer laser radiation

NASA Astrophysics Data System (ADS)

Temme, Thorsten; Ostendorf, Andreas; Kulik, Christian; Meyer, Klaus

2003-07-01

μFor drilling fused silica, mechanical techniques like with diamond drills, ultrasonic machining, sand blasting or water jet machining are used. Also chemical techniques like laser assisted wet etching or thermal drilling with CO2-lasers are established. As an extension of these technologies, the drilling of micro-holes in fused silica with VUV laser radiation is presented here. The high absorption of the 157 nm radiation emitted by the F2 excimer laser and the short pulse duration lead to a material ablation with minimised impact on the surrounding material. Contrary to CO2-laser drilling, a molten and solidified phase around the bore can thus be avoided. The high photon energy of 7.9 eV requires either high purity nitrogen flushing or operation in vacuum, which also effects the processing results. Depending on the required precision, the laser can be used for percussion drilling as well as for excimer laser trepanning, by applying rotating masks. Rotating masks are especially used for high aspect ratio drilling with well defined edges and minimised debris. The technology is suitable particularly for holes with a diameter below 200 μm down to some microns in substrates with less than 200 μm thickness, that can not be achieved with mechanical methods. Drilling times in 200 μm fused silica substrates are in the range of ten seconds, which is sufficient to compete with conventional methods while providing similar or even better accuracy.

Lithography-free glass surface modification by self-masking during dry etching

NASA Astrophysics Data System (ADS)

Hein, Eric; Fox, Dennis; Fouckhardt, Henning

2011-01-01

Glass surface morphologies with defined shapes and roughness are realized by a two-step lithography-free process: deposition of an ~10-nm-thin lithographically unstructured metallic layer onto the surface and reactive ion etching in an Ar/CF4 high-density plasma. Because of nucleation or coalescence, the metallic layer is laterally structured during its deposition. Its morphology exhibits islands with dimensions of several tens of nanometers. These metal spots cause a locally varying etch velocity of the glass substrate, which results in surface structuring. The glass surface gets increasingly rougher with further etching. The mechanism of self-masking results in the formation of surface structures with typical heights and lateral dimensions of several hundred nanometers. Several metals, such as Ag, Al, Au, Cu, In, and Ni, can be employed as the sacrificial layer in this technology. Choice of the process parameters allows for a multitude of different glass roughness morphologies with individual defined and dosed optical scattering.

Ink-jet printing technology enables self-aligned mould patterning for electroplating in a single step

NASA Astrophysics Data System (ADS)

Meissner, M. V.; Spengler, N.; Mager, D.; Wang, N.; Kiss, S. Z.; Höfflin, J.; While, P. T.; Korvink, J. G.

2015-06-01

We present a new self-aligned, mask-free micro-fabrication method with which to form thick-layered conductive metal micro-structures inside electroplating moulds. Seed layer patterning for electroplating was performed by ink-jet printing using a silver nano-particle ink deposited on SU-8 or Ordyl SY permanent resist. The silver ink contact angle on SU-8 was adjusted by oxygen plasma followed by a hard bake. Besides functioning as a seed layer, the printed structures further served as a shadow mask during patterning of electroplating moulds into negative photoresist. The printed silver tracks remained in strong adhesion to the substrate when exposed to the acidic chemistry of the electroplating bath. To demonstrate the process, we manufactured rectangular, low-resistivity planar micro-coils for use in magnetic resonance microscopy. MRI images of a spring onion with an in-plane resolution down to 10 µm × 10 µm were acquired using a micro-coil on an 11.7 T MRI scanner.

Large area nanoscale metal meshes for use as transparent conductive layers.

PubMed

Jin, Yuanhao; Li, Qunqing; Chen, Mo; Li, Guanhong; Zhao, Yudan; Xiao, Xiaoyang; Wang, Jiaping; Jiang, Kaili; Fan, Shoushan

2015-10-21

We report on the experimental realization of using super-aligned carbon nanotubes (SACNTs) as etching masks for the fabrication of large area nanoscale metal meshes. This method can easily be extended to different metals on both rigid and flexible substrates. The as-fabricated metal meshes, including the ones made of gold, copper, and aluminum, are suitable for use as transparent conductive layers (TCLs). The metal meshes, which are similar to the SACNT networks in their dimensional features of tens of nanometers, exhibit compatible performance in terms of optical transmittance and sheet resistance. Moreover, because the metal meshes are fabricated as an integrated material, there is no junction resistance between the interconnected metal nanostructures, which markedly lowers their sheet resistance at high temperatures. The fabrication of such an effective etching mask involves a simple drawing process of the SACNT networks prepared and a common deposition process. This approach should be easy to extend to various research fields and has broad prospects in commercial applications.

Diameter and location control of ZnO nanowires using electrodeposition and sodium citrate

NASA Astrophysics Data System (ADS)

Lifson, Max L.; Levey, Christopher G.; Gibson, Ursula J.

2013-10-01

We report single-step growth of spatially localized ZnO nanowires of controlled diameter to enable improved performance of piezoelectric devices such as nanogenerators. This study is the first to demonstrate the combination of electrodeposition with zinc nitrate and sodium citrate in the growth solution. Electrodeposition through a thermally-grown silicon oxide mask results in localization, while the growth voltage and solution chemistry are tuned to control the nanowire geometry. We observe a competition between lateral (relative to the (0001) axis) citrate-related morphology and voltage-driven vertical growth which enables this control. High aspect ratios result with either pure nitrate or nitrate-citrate mixtures if large voltages are used, but low growth voltages permit the growth of large diameter nanowires in solution with citrate. Measurements of the current density suggest a two-step growth process. An oxide mask blocks the electrodeposition, and suppresses nucleation of thermally driven growth, permitting single-step lithography on low cost p-type silicon substrates.

Disinhibition outside receptive fields in the visual cortex.

PubMed

Walker, Gary A; Ohzawa, Izumi; Freeman, Ralph D

2002-07-01

By definition, the region outside the classical receptive field (CRF) of a neuron in the visual cortex does not directly activate the cell. However, the response of a neuron can be influenced by stimulation of the surrounding area. In previous work, we showed that this influence is mainly suppressive and that it is generally limited to a local region outside the CRF. In the experiments reported here, we investigate the mechanisms of the suppressive effect. Our approach is to find the position of a grating patch that is most effective in suppressing the response of a cell. We then use a masking stimulus at different contrasts over the grating patch in an attempt to disinhibit the response. We find that suppressive effects may be partially or completely reversed by use of the masking stimulus. This disinhibition suggests that effects from outside the CRF may be local. Although they do not necessarily underlie the perceptual analysis of a figure-ground visual scene, they may provide a substrate for this process.

High-charge and multiple-star vortex coronagraphy from stacked vector vortex phase masks.

PubMed

Aleksanyan, Artur; Brasselet, Etienne

2018-02-01

Optical vortex phase masks are now installed at many ground-based large telescopes for high-contrast astronomical imaging. To date, such instrumental advances have been restricted to the use of helical phase masks of the lowest even order, while future giant telescopes will require high-order masks. Here we propose a single-stage on-axis scheme to create high-order vortex coronagraphs based on second-order vortex phase masks. By extending our approach to an off-axis design, we also explore the implementation of multiple-star vortex coronagraphy. An experimental laboratory demonstration is reported and supported by numerical simulations. These results offer a practical roadmap to the development of future coronagraphic tools with enhanced performances.

Future reticle demand and next-generation lithography technologies

NASA Astrophysics Data System (ADS)

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

1999-04-01

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

Disposable surgical face masks for preventing surgical wound infection in clean surgery.

PubMed

Lipp, Allyson; Edwards, Peggy

2014-02-17

Surgical face masks were originally developed to contain and filter droplets containing microorganisms expelled from the mouth and nasopharynx of healthcare workers during surgery, thereby providing protection for the patient. However, there are several ways in which surgical face masks could potentially contribute to contamination of the surgical wound, e.g. by incorrect wear or by leaking air from the side of the mask due to poor string tension. To determine whether disposable surgical face masks worn by the surgical team during clean surgery prevent postoperative surgical wound infection. We searched The Cochrane Wounds Group Specialised Register on 23 October 2013; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. Randomised controlled trials (RCTs) and quasi-randomised controlled trials comparing the use of disposable surgical masks with the use of no mask. Two review authors extracted data independently. Three trials were included, involving a total of 2113 participants. There was no statistically significant difference in infection rates between the masked and unmasked group in any of the trials. From the limited results it is unclear whether the wearing of surgical face masks by members of the surgical team has any impact on surgical wound infection rates for patients undergoing clean surgery.

Development of an Operational Land Water Mask for MODIS Collection 6, and Influence on Downstream Data Products

NASA Technical Reports Server (NTRS)

Carroll, M. L.; DiMiceli, C. M.; Townshend, J. R. G.; Sohlberg, R. A.; Elders, A. I.; Devadiga, S.; Sayer, A. M.; Levy, R. C.

2016-01-01

Data from the Moderate Resolution Imaging Spectro-radiometer (MODIS)on-board the Earth Observing System Terra and Aqua satellites are processed using a land water mask to determine when an algorithm no longer needs to be run or when an algorithm needs to follow a different pathway. Entering the fourth reprocessing (Collection 6 (C6)) the MODIS team replaced the 1 km water mask with a 500 m water mask for improved representation of the continental surfaces. The new water mask represents more small water bodies for an overall increase in water surface from 1 to 2 of the continental surface. While this is still a small fraction of the overall global surface area the increase is more dramatic in certain areas such as the Arctic and Boreal regions where there are dramatic increases in water surface area in the new mask. MODIS products generated by the on-going C6 reprocessing using the new land water mask show significant impact in areas with high concentrations of change in the land water mask. Here differences between the Collection 5 (C5) and C6 water masks and the impact of these differences on the MOD04 aerosol product and the MOD11 land surface temperature product are shown.

Aerosol jet printed silver nanowire transparent electrode for flexible electronic application

NASA Astrophysics Data System (ADS)

Tu, Li; Yuan, Sijian; Zhang, Huotian; Wang, Pengfei; Cui, Xiaolei; Wang, Jiao; Zhan, Yi-Qiang; Zheng, Li-Rong

2018-05-01

Aerosol jet printing technology enables fine feature deposition of electronic materials onto low-temperature, non-planar substrates without masks. In this work, silver nanowires (AgNWs) are proposed to be printed into transparent flexible electrodes using a Maskless Mesoscale Material Deposition Aerosol Jet® printing system on a glass substrate. The influence of the most significant process parameters, including printing cycles, printing speed, and nozzle size, on the performance of AgNW electrodes was systematically studied. The morphologies of printed patterns were characterized by scanning electron microscopy, and the transmittance was evaluated using an ultraviolet-visible spectrophotometer. Under optimum conditions, high transparent AgNW electrodes with a sheet resistance of 57.68 Ω/sq and a linewidth of 50.9 μm were obtained, which is an important step towards a higher performance goal for flexible electronic applications.

Metal catalyst technique for texturing silicon solar cells

DOEpatents

Ruby, Douglas S.; Zaidi, Saleem H.

2001-01-01

Textured silicon solar cells and techniques for their manufacture utilizing metal sources to catalyze formation of randomly distributed surface features such as nanoscale pyramidal and columnar structures. These structures include dimensions smaller than the wavelength of incident light, thereby resulting in a highly effective anti-reflective surface. According to the invention, metal sources present in a reactive ion etching chamber permit impurities (e.g. metal particles) to be introduced into a reactive ion etch plasma resulting in deposition of micro-masks on the surface of a substrate to be etched. Separate embodiments are disclosed including one in which the metal source includes one or more metal-coated substrates strategically positioned relative to the surface to be textured, and another in which the walls of the reaction chamber are pre-conditioned with a thin coating of metal catalyst material.

Large scale ZnTe nanostructures on polymer micro patterns via capillary force photolithography

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

Florence, S. Sasi, E-mail: sshanmugaraj@jazanu.edu.sa; Can, N.; Adam, H.

2016-06-10

A novel approach to prepare micro patterns ZnTe nanostructures on Si (100) substrate using thermal evaporation is proposed by capillary Force Lithography (CFL) technique on a self-assembled sacrificial Polystyrene mask. Polystyrene thin films on Si substrates are used to fabricate surface micro-relief patterns. ZnTe nanoparticles have been deposited by thermal evaporation method. The deposited ZnTe nanoparticles properties were assessed by Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM). SEM studies indicated that the particles are uniform in size and shape, well dispersed and spherical in shape. This study reports the micro-arrays of ZnTe nanoparticles on a self-assembled sacrificial PS maskmore » using a capillary flow photolithography process which showed excellent, morphological properties which can be used in photovoltaic devices for anti-reflection applications.« less

Ion sensitivity of large-area epitaxial graphene film on SiC substrate

NASA Astrophysics Data System (ADS)

Mitsuno, Takanori; Taniguchi, Yoshiaki; Ohno, Yasuhide; Nagase, Masao

2017-11-01

We investigated the intrinsic ion sensitivity of graphene field-effect transistors (FETs) fabricated by a resist-free stencil mask lithography process from a large-scale graphene film epitaxially grown on a SiC substrate. A pH-adjusted phosphate-buffered solution was used for the measurement to eliminate the interference of other ions on the graphene FET's ion sensitivity. The charge neutrality point shifted negligibly with changing pH for the pH-adjusted phosphate-buffered solution, whereas for the mixed buffer solution, it shifted toward the negative gate voltage owing to the decrease in the concentration of phthalate ions. This phenomenon is contrary to that observed in previous reports. Overall, our results indicate that the graphene film is intrinsically insensitive to ions except for those with functional groups that interact with the graphene surface.

Ensuring Confidentiality of Geocoded Health Data: Assessing Geographic Masking Strategies for Individual-Level Data.

PubMed

Zandbergen, Paul A

2014-01-01

Public health datasets increasingly use geographic identifiers such as an individual's address. Geocoding these addresses often provides new insights since it becomes possible to examine spatial patterns and associations. Address information is typically considered confidential and is therefore not released or shared with others. Publishing maps with the locations of individuals, however, may also breach confidentiality since addresses and associated identities can be discovered through reverse geocoding. One commonly used technique to protect confidentiality when releasing individual-level geocoded data is geographic masking. This typically consists of applying a certain amount of random perturbation in a systematic manner to reduce the risk of reidentification. A number of geographic masking techniques have been developed as well as methods to quantity the risk of reidentification associated with a particular masking method. This paper presents a review of the current state-of-the-art in geographic masking, summarizing the various methods and their strengths and weaknesses. Despite recent progress, no universally accepted or endorsed geographic masking technique has emerged. Researchers on the other hand are publishing maps using geographic masking of confidential locations. Any researcher publishing such maps is advised to become familiar with the different masking techniques available and their associated reidentification risks.

CD-measurement technique for hole patterns on stencil mask

NASA Astrophysics Data System (ADS)

Ishikawa, Mikio; Yusa, Satoshi; Takikawa, Tadahiko; Fujita, Hiroshi; Sano, Hisatake; Hoga, Morihisa; Hayashi, Naoya

2004-12-01

EB lithography has a potential to successfully form hole patterns as small as 80 nm with a stencil mask. In a previous paper we proposed a technique using a HOLON dual-mode critical dimension (CD) SEM ESPA-75S in the transmission mode for CD measurement of line-and-space patterns on a stencil mask. In this paper we extend our effort of developing a CD measurement technique to contact hole features and determine it in comparison of measured values between features on mask and those printed on wafer. We have evaluated the width method and the area methods using designed 80-500 nm wide contact hole patterns on a large area membrane mask and their resist images on wafer printed by a LEEPL3000. We find that 1) the width method and the area methods show an excellent mask-wafer correlation for holes over 110 nm, and 2) the area methods show a better mask-wafer correlation than the width method does for holes below 110 nm. We conclude that the area calculated from the transmission SEM image is more suitable in defining the hole dimensions than the width for contact holes on a stencil mask.

Novel optical interconnect devices and coupling methods applying self-written waveguide technology

NASA Astrophysics Data System (ADS)

Nakama, Kenichi; Mikami, Osamu

2011-05-01

For the use in cost-effective optical interconnection of opt-electronic printed wiring boards (OE-PWBs), we have developed novel optical interconnect devices and coupling methods simplifying board to board optical interconnect. All these are based on the self-written waveguide (SWW) technology by the mask-transfer method with light-curable resin. This method enables fabrication of arrayed M × N optical channels at one shot of UV light. Very precise patterns, as an example, optical rod with diameters of 50μm to 500μm, can be easily fabricated. The length of the fabricated patterns ,, typically up to about 1000μm , can be controlled by a spacer placed between the photomask and the substrate. Using these technologies, several new optical interfaces have been demonstrated. These are a chip VCSEL with an optical output rod and new coupling methods of "plug-in" alignment and "optical socket" based on SWW.

Effect of Palagonite Dust Deposition on the Automated Detection of Carbonate Vis/NIR Spectra

NASA Technical Reports Server (NTRS)

Gilmore, Martha S.; Merrill, Matthew D.; Castano, Rebecca; Bornstein, Benjamin; Greenwood, James

2004-01-01

Currently Mars missions can collect more data than can be returned. Future rovers of increased mission lifetime will benefit from onboard autonomous data processing systems to guide the selection, measurement and return of scientifically important data. One approach is to train a neural net to recognize spectral reflectance characteristics of minerals of interest. We have developed a carbonate detector using a neural net algorithm trained on 10,000 synthetic Vis/NIR (350-2500 nm) spectra. The detector was able to correctly identify carbonates in the spectra of 30 carbonate and noncarbonate field samples with 100% success. However, Martian dust coatings strongly affect the spectral characteristics of surface rocks potentially masking the underlying substrate rock. In this experiment, we measure Vis/NIR spectra of calcite coated with different thicknesses of palagonite dust and evaluate the performance of the carbonate detector.

Antireflective surface with a step in the taper: Numerical optimization and large-area fabrication

NASA Astrophysics Data System (ADS)

Shinotsuka, Kei; Hongo, Koki; Dai, Kotaro; Hirama, Satoru; Hatta, Yoshihisa

2017-02-01

In this study, we developed a practical method to improve the optical performance of subwavelength antireflective two-dimensional (2D) gratings. A numerical simulation of both convex and concave paraboloids suggested that surface reflectivity drastically decreases when a step is introduced in the taper. The optimum height and depth of a step provided average reflectances of 0.098% for convex protrusions and 0.040% for concave protrusions in the visible range. Furthermore, a stepped paraboloid was experimentally fabricated by dry etching of a Si substrate with SiO2 particle monolayer mask. A cyclo-olefin polymer (COP) reverse replica (concave) imprinted by the Si mold exhibited a measured reflectance of 0.077% on average in the visible range. It was also demonstrated that the antireflective structure was fabricated on the whole surface of a 6 in. Si wafer, which is a sufficient size for industrial utilization.

Micro sculpting technology using DPSSL

NASA Astrophysics Data System (ADS)

Chang, Won-Seok; Shin, Bosung; Kim, Jae-gu; Whang, Kyung-Hyun

2003-11-01

Multiple pulse laser ablation of polymer is performed with DPSS (Diode Pumped Solid State) 3rd harmonic Nd:YVO4 laser (355 nm) in order to fabricate three-dimensional micro components. Here we considered mechanistic aspects of the interaction between UV laser and polymer to obtain optimum process conditions for maskless photomachining using DPSSL. The photo-physical and photochemical parameters such as laser wavelength and optical characteristics of polymers are investigated by experiments to reduce plume effect, which induce the re-deposited debris on the surface of substrate. In this study, LDST (laser direct sculpting technique) are developed to gain various three-dimensional shape with size less than 500 micrometer. Main process sequences are from rapid prototyping technology such as CAD/CAM modeling of products, machining path generation, layer-by-layer machining, and so on. This method can be applied to manufacture the prototype of micro device and the polymer mould for mass production without expensive mask fabrication.

Titanium dioxide fine structures by RF magnetron sputter method deposited on an electron-beam resist mask

NASA Astrophysics Data System (ADS)

Hashiba, Hideomi; Miyazaki, Yuta; Matsushita, Sachiko

2013-09-01

Titanium dioxide (TiO2) has been draw attention for wide range of applications from photonic crystals for visible light range by its catalytic characteristics to tera-hertz range by its high refractive index. We present an experimental study of fabrication of fine structures of TiO2 with a ZEP electron beam resist mask followed by Ti sputter deposition techniques. A TiO2 thin layer of 150 nm thick was grown on an FTO glass substrate with a fine patterned ZEP resist mask by a conventional RF magnetron sputter method with Ti target. The deposition was carried out with argon-oxygen gases at a pressure of 5.0 x 10 -1 Pa in a chamber. During the deposition, ratio of Ar-O2 gas was kept to the ratio of 2:1 and the deposition ratio was around 0.5 Å/s to ensure enough oxygen to form TiO2 and low temperature to avoid deformation of fine pattern of the ZPU resist mask. Deposited TiO2 layers are white-transparent, amorphous, and those roughnesses are around 7 nm. Fabricated TiO2 PCs have wider TiO2 slabs of 112 nm width leaving periodic 410 x 410 nm2 air gaps. We also studied transformation of TiO2 layers and TiO2 fine structures by baking at 500 °C. XRD measurement for TiO2 shows that the amorphous TiO2 transforms to rutile and anatase forms by the baking while keeping the same profile of the fine structures. Our fabrication method can be one of a promising technique to optic devices on researches and industrial area.

A novel anti-influenza copper oxide containing respiratory face mask.

PubMed

Borkow, Gadi; Zhou, Steve S; Page, Tom; Gabbay, Jeffrey

2010-06-25

Protective respiratory face masks protect the nose and mouth of the wearer from vapor drops carrying viruses or other infectious pathogens. However, incorrect use and disposal may actually increase the risk of pathogen transmission, rather than reduce it, especially when masks are used by non-professionals such as the lay public. Copper oxide displays potent antiviral properties. A platform technology has been developed that permanently introduces copper oxide into polymeric materials, conferring them with potent biocidal properties. We demonstrate that impregnation of copper oxide into respiratory protective face masks endows them with potent biocidal properties in addition to their inherent filtration properties. Both control and copper oxide impregnated masks filtered above 99.85% of aerosolized viruses when challenged with 5.66+/-0.51 and 6.17+/-0.37 log(10)TCID(50) of human influenza A virus (H1N1) and avian influenza virus (H9N2), respectively, under simulated breathing conditions (28.3 L/min). Importantly, no infectious human influenza A viral titers were recovered from the copper oxide containing masks within 30 minutes (< or = 0.88 log(10)TCID(50)), while 4.67+/-1.35 log(10)TCID(50) were recovered from the control masks. Similarly, the infectious avian influenza titers recovered from the copper oxide containing masks were < or = 0.97+/-0.01 log(10)TCID(50) and from the control masks 5.03+/-0.54 log(10)TCID(50). The copper oxide containing masks successfully passed Bacterial Filtration Efficacy, Differential Pressure, Latex Particle Challenge, and Resistance to Penetration by Synthetic Blood tests designed to test the filtration properties of face masks in accordance with the European EN 14683:2005 and NIOSH N95 standards. Impregnation of copper oxide into respiratory protective face masks endows them with potent anti-influenza biocidal properties without altering their physical barrier properties. The use of biocidal masks may significantly reduce the risk of hand or environmental contamination, and thereby subsequent infection, due to improper handling and disposal of the masks.

Overview and development of EDA tools for integration of DSA into patterning solutions

NASA Astrophysics Data System (ADS)

Torres, J. Andres; Fenger, Germain; Khaira, Daman; Ma, Yuansheng; Granik, Yuri; Kapral, Chris; Mitra, Joydeep; Krasnova, Polina; Ait-Ferhat, Dehia

2017-03-01

Directed Self-Assembly is the method by which a self-assembly polymer is forced to follow a desired geometry defined or influenced by a guiding pattern. Such guiding pattern uses surface potentials, confinement or both to achieve polymer configurations that result in circuit-relevant topologies, which can be patterned onto a substrate. Chemo, and grapho epitaxy of lines and space structures are now routinely inspected at full wafer level to understand the defectivity limits of the materials and their maximum resolution. In the same manner, there is a deeper understanding about the formation of cylinders using grapho-epitaxy processes. Academia has also contributed by developing methods that help reduce the number of masks in advanced nodes by "combining" DSA-compatible groups, thus reducing the total cost of the process. From the point of view of EDA, new tools are required when a technology is adopted, and most technologies are adopted when they show a clear cost-benefit over alternative techniques. In addition, years of EDA development have led to the creation of very flexible toolkits that permit rapid prototyping and evaluation of new process alternatives. With the development of high-chi materials, and by moving away of the well characterized PS-PMMA systems, as well as novel integrations in the substrates that work in tandem with diblock copolymer systems, it is necessary to assess any new requirements that may or may not need custom tools to support such processes. Hybrid DSA processes (which contain both chemo and grapho elements), are currently being investigated as possible contenders for sub-5nm process techniques. Because such processes permit the re-distribution of discontinuities in the regular arrays between the substrate and a cut operation, they have the potential to extend the number of applications for DSA. This paper illustrates the reason as to why some DSA processes can be supported by existing rules and technology, while other processes require the development of highly customized correction tools and models. It also illustrates how developing DSA cannot be done in isolation, and it requires the full collaboration of EDA, Material's suppliers, Manufacturing equipment, Metrology, and electronic manufacturers.

[Effect of oxygen tubing connection site on percutaneous oxygen partial pressure and percutaneous carbon dioxide partial pressure in patients with chronic obstructive pulmonary disease during noninvasive positive pressure ventilation].

PubMed

Mi, S; Zhang, L M

2017-04-12

Objective: We evaluated the effects of administering oxygen through nasal catheters inside the mask or through the mask on percutaneous oxygen partial pressure (PcO(2))and percutaneous carbon dioxide partial pressure (PcCO(2)) during noninvasive positive pressure ventilation (NPPV) to find a better way of administering oxygen, which could increase PcO(2) by increasing the inspired oxygen concentration. Methods: Ten healthy volunteers and 9 patients with chronic obstructive pulmonary disease complicated by type Ⅱ respiratory failure were included in this study. Oxygen was administered through a nasal catheter inside the mask or through the mask (oxygen flow was 3 and 5 L/min) during NPPV. PcO(2) and PcCO(2) were measured to evaluate the effects of administering oxygen through a nasal catheter inside the mask or through the mask, indirectly reflecting the effects of administering oxygen through nasal catheter inside the mask or through the mask on inspired oxygen concentration. Results: Compared to administering oxygen through the mask during NPPV, elevated PcO(2) was measured in administering oxygen through the nasal catheter inside the mask, and the differences were statistically significant ( P <0.05). At the same time, there was no significant change in PcCO(2) ( P >0.05). Conclusion: Administering oxygen through a nasal catheter inside the mask during NPPV increased PcO(2) by increasing the inspired oxygen concentration but did not increase PcCO(2). This method of administering oxygen could conserve oxygen and be suitable for family NPPV. Our results also provided theoretical basis for the development of new masks.

Unconscious processing of facial affect in children and adolescents.

PubMed

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

2007-01-01

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

Development of a detachable high speed miniature scanning probe microscope for large area substrates inspection

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

Sadeghian, Hamed, E-mail: hamed.sadeghianmarnani@tno.nl, E-mail: h.sadeghianmarnani@tudelft.nl; Department of Precision and Microsystems Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft; Herfst, Rodolf

We have developed a high speed, miniature scanning probe microscope (MSPM) integrated with a Positioning Unit (PU) for accurately positioning the MSPM on a large substrate. This combination enables simultaneous, parallel operation of many units on a large sample for high throughput measurements. The size of the MSPM is 19 × 45 × 70 mm{sup 3}. It contains a one-dimensional flexure stage with counter-balanced actuation for vertical scanning with a bandwidth of 50 kHz and a z-travel range of more than 2 μm. This stage is mechanically decoupled from the rest of the MSPM by suspending it on specific dynamicallymore » determined points. The motion of the probe, which is mounted on top of the flexure stage is measured by a very compact optical beam deflection (OBD). Thermal noise spectrum measurements of short cantilevers show a bandwidth of 2 MHz and a noise of less than 15 fm/Hz{sup 1/2}. A fast approach and engagement of the probe to the substrate surface have been achieved by integrating a small stepper actuator and direct monitoring of the cantilever response to the approaching surface. The PU has the same width as the MSPM, 45 mm and can position the MSPM to a pre-chosen position within an area of 275×30 mm{sup 2} to within 100 nm accuracy within a few seconds. During scanning, the MSPM is detached from the PU which is essential to eliminate mechanical vibration and drift from the relatively low-resonance frequency and low-stiffness structure of the PU. Although the specific implementation of the MSPM we describe here has been developed as an atomic force microscope, the general architecture is applicable to any form of SPM. This high speed MSPM is now being used in a parallel SPM architecture for inspection and metrology of large samples such as semiconductor wafers and masks.« less

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

NASA Astrophysics Data System (ADS)

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

2012-11-01

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

Objective evaluation of the knocking sound of a diesel engine considering the temporal and frequency masking effect simultaneously

NASA Astrophysics Data System (ADS)

Yun, Dong-Un; Lee, Sang-Kwon

2017-06-01

In this paper, we present a novel method for an objective evaluation of knocking noise emitted by diesel engines based on the temporal and frequency masking theory. The knocking sound of a diesel engine is a vibro-acoustic sound correlated with the high-frequency resonances of the engine structure and a periodic impulsive sound with amplitude modulation. Its period is related to the engine speed and includes specific frequency bands related to the resonances of the engine structure. A knocking sound with the characteristics of a high-frequency impulsive wave can be masked by low-frequency sounds correlated with the harmonics of the firing frequency and broadband noise. The degree of modulation of the knocking sound signal was used for such objective evaluations in previous studies, without considering the masking effect. However, the frequency masking effect must be considered for the objective evaluation of the knocking sound. In addition to the frequency masking effect, the temporal masking effect occurs because the period of the knocking sound changes according to the engine speed. Therefore, an evaluation method considering the temporal and frequency masking effect is required to analyze the knocking sound objectively. In this study, an objective evaluation method considering the masking effect was developed based on the masking theory of sound and signal processing techniques. The method was applied successfully for the objective evaluation of the knocking sound of a diesel engine.

Automatic Masking for Robust 3D-2D Image Registration in Image-Guided Spine Surgery.

PubMed

Ketcha, M D; De Silva, T; Uneri, A; Kleinszig, G; Vogt, S; Wolinsky, J-P; Siewerdsen, J H

During spinal neurosurgery, patient-specific information, planning, and annotation such as vertebral labels can be mapped from preoperative 3D CT to intraoperative 2D radiographs via image-based 3D-2D registration. Such registration has been shown to provide a potentially valuable means of decision support in target localization as well as quality assurance of the surgical product. However, robust registration can be challenged by mismatch in image content between the preoperative CT and intraoperative radiographs, arising, for example, from anatomical deformation or the presence of surgical tools within the radiograph. In this work, we develop and evaluate methods for automatically mitigating the effect of content mismatch by leveraging the surgical planning data to assign greater weight to anatomical regions known to be reliable for registration and vital to the surgical task while removing problematic regions that are highly deformable or often occluded by surgical tools. We investigated two approaches to assigning variable weight (i.e., "masking") to image content and/or the similarity metric: (1) masking the preoperative 3D CT ("volumetric masking"); and (2) masking within the 2D similarity metric calculation ("projection masking"). The accuracy of registration was evaluated in terms of projection distance error (PDE) in 61 cases selected from an IRB-approved clinical study. The best performing of the masking techniques was found to reduce the rate of gross failure (PDE > 20 mm) from 11.48% to 5.57% in this challenging retrospective data set. These approaches provided robustness to content mismatch and eliminated distinct failure modes of registration. Such improvement was gained without additional workflow and has motivated incorporation of the masking methods within a system under development for prospective clinical studies.

Automatic masking for robust 3D-2D image registration in image-guided spine surgery

NASA Astrophysics Data System (ADS)

Ketcha, M. D.; De Silva, T.; Uneri, A.; Kleinszig, G.; Vogt, S.; Wolinsky, J.-P.; Siewerdsen, J. H.

2016-03-01

During spinal neurosurgery, patient-specific information, planning, and annotation such as vertebral labels can be mapped from preoperative 3D CT to intraoperative 2D radiographs via image-based 3D-2D registration. Such registration has been shown to provide a potentially valuable means of decision support in target localization as well as quality assurance of the surgical product. However, robust registration can be challenged by mismatch in image content between the preoperative CT and intraoperative radiographs, arising, for example, from anatomical deformation or the presence of surgical tools within the radiograph. In this work, we develop and evaluate methods for automatically mitigating the effect of content mismatch by leveraging the surgical planning data to assign greater weight to anatomical regions known to be reliable for registration and vital to the surgical task while removing problematic regions that are highly deformable or often occluded by surgical tools. We investigated two approaches to assigning variable weight (i.e., "masking") to image content and/or the similarity metric: (1) masking the preoperative 3D CT ("volumetric masking"); and (2) masking within the 2D similarity metric calculation ("projection masking"). The accuracy of registration was evaluated in terms of projection distance error (PDE) in 61 cases selected from an IRB-approved clinical study. The best performing of the masking techniques was found to reduce the rate of gross failure (PDE > 20 mm) from 11.48% to 5.57% in this challenging retrospective data set. These approaches provided robustness to content mismatch and eliminated distinct failure modes of registration. Such improvement was gained without additional workflow and has motivated incorporation of the masking methods within a system under development for prospective clinical studies.

65-nm full-chip implementation using double dipole lithography

NASA Astrophysics Data System (ADS)

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

2003-06-01

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

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.

The Effect of the Elimination of Micromotion and Tissue Strain on Intracortical Device Performance

DTIC Science & Technology

2017-10-01

dry mode and after soaking for 60 min in PBS at 37 °C. 6 3. Connectivity Issue: An additional issue emerged while trying to establish an electrical...patterned to dry etch the Parylene-C film using DMA ribbons photo mask using O2 plasma. The photoresist is then stripped off to get the wafers ready for...investigated visually by the naked eye and with an optical microscope and only those who pass (substrates with very low number of small particles, if

Polymeric matrix materials for infrared metamaterials

DOEpatents

Dirk, Shawn M; Rasberry, Roger D; Rahimian, Kamyar

2014-04-22

A polymeric matrix material exhibits low loss at optical frequencies and facilitates the fabrication of all-dielectric metamaterials. The low-loss polymeric matrix material can be synthesized by providing an unsaturated polymer, comprising double or triple bonds; partially hydrogenating the unsaturated polymer; depositing a film of the partially hydrogenated polymer and a crosslinker on a substrate; and photopatterning the film by exposing the film to ultraviolet light through a patterning mask, thereby cross-linking at least some of the remaining unsaturated groups of the partially hydrogenated polymer in the exposed portions.

Reflective optical imaging systems with balanced distortion

DOEpatents

Hudyma, Russell M.

2001-01-01

Optical systems compatible with extreme ultraviolet radiation comprising four reflective elements for projecting a mask image onto a substrate are described. The four optical elements comprise, in order from object to image, convex, concave, convex and concave mirrors. The optical systems are particularly suited for step and scan lithography methods. The invention enables the use of larger slit dimensions associated with ring field scanning optics, improves wafer throughput, and allows higher semiconductor device density. The inventive optical systems are characterized by reduced dynamic distortion because the static distortion is balanced across the slit width.

A multicentre phase III randomised controlled single-masked clinical trial evaluating the clinical efficacy and safety of light-masks at preventing dark-adaptation in the treatment of early diabetic macular oedema (CLEOPATRA): study protocol for a randomised controlled trial.

PubMed

Sivaprasad, Sobha; Arden, Geoffrey; Prevost, A Toby; Crosby-Nwaobi, Roxanne; Holmes, Helen; Kelly, Joanna; Murphy, Caroline; Rubin, Gary; Vasconcelos, Joanna; Hykin, Philip

2014-11-22

This study will evaluate hypoxia, as a novel concept in the pathogenesis of diabetic macular oedema (DMO). As the oxygen demand of the eye is maximum during dark-adaptation, we hypothesize that wearing light-masks during sleep will cause regression and prevent the development and progression of DMO. The study protocol comprises both an efficacy and mechanistic evaluation to test this hypothesis. This is a phase III randomised controlled single-masked multicentre clinical trial to test the clinical efficacy of light-masks at preventing dark-adaptation in the treatment of non-central DMO. Three hundred patients with non-centre-involving DMO in at least one eye will be randomised 1:1 to light-masks and control masks (with no light) to be used during sleep at night for a period of 24 months. The primary outcome is regression of non-central oedema by assessing change in the zone of maximal retinal thickness at baseline on optical coherence tomography (SD-OCT). Secondary outcomes will evaluate the prevention of development and progression of DMO by assessing changes in retinal thickness in different regions of the macula, macular volume, refracted visual acuity and level of retinopathy. Safety parameters will include sleep disturbance. Adverse events and measures of compliance will be assessed over 24 months. Participants recruited to the mechanistic sub-study will have additional retinal oximetry, multifocal electroretinography (ERG) and microperimetry to evaluate the role of hypoxia by assessing and comparing changes induced by supplemental oxygen and the light-masks at 12 months. The outcomes of this study will provide insight into the pathogenesis of DMO and provide evidence on whether a simple, non-invasive device in the form of a light-mask can help prevent the progression to centre-involving DMO and visual impairment in people with diabetes.

Analysis of geostationary satellite-derived cloud parameters associated with environments with high ice water content

NASA Astrophysics Data System (ADS)

de Laat, Adrianus; Defer, Eric; Delanoë, Julien; Dezitter, Fabien; Gounou, Amanda; Grandin, Alice; Guignard, Anthony; Fokke Meirink, Jan; Moisselin, Jean-Marc; Parol, Frédéric

2017-04-01

We present an evaluation of the ability of passive broadband geostationary satellite measurements to detect high ice water content (IWC > 1 g m-3) as part of the European High Altitude Ice Crystals (HAIC) project for detection of upper-atmospheric high IWC, which can be a hazard for aviation. We developed a high IWC mask based on measurements of cloud properties using the Cloud Physical Properties (CPP) algorithm applied to the geostationary Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI). Evaluation of the high IWC mask with satellite measurements of active remote sensors of cloud properties (CLOUDSAT/CALIPSO combined in the DARDAR (raDAR-liDAR) product) reveals that the high IWC mask is capable of detecting high IWC values > 1 g m-3 in the DARDAR profiles with a probability of detection of 60-80 %. The best CPP predictors of high IWC were the condensed water path, cloud optical thickness, cloud phase, and cloud top height. The evaluation of the high IWC mask against DARDAR provided indications that the MSG-CPP high IWC mask is more sensitive to cloud ice or cloud water in the upper part of the cloud, which is relevant for aviation purposes. Biases in the CPP results were also identified, in particular a solar zenith angle (SZA) dependence that reduces the performance of the high IWC mask for SZAs > 60°. Verification statistics show that for the detection of high IWC a trade-off has to be made between better detection of high IWC scenes and more false detections, i.e., scenes identified by the high IWC mask that do not contain IWC > 1 g m-3. However, the large majority of these detections still contain IWC values between 0.1 and 1 g m-3. Comparison of the high IWC mask against results from the Rapidly Developing Thunderstorm (RDT) algorithm applied to the same geostationary SEVIRI data showed that there are similarities and differences with the high IWC mask: the RDT algorithm is very capable of detecting young/new convective cells and areas, whereas the high IWC mask appears to be better capable of detecting more mature and ageing convection as well as cirrus remnants. The lack of detailed understanding of what causes aviation hazards related to high IWC, as well as the lack of clearly defined user requirements, hampers further tuning of the high IWC mask. Future evaluation of the high IWC mask against field campaign data, as well as obtaining user feedback and user requirements from the aviation industry, should provide more information on the performance of the MSG-CPP high IWC mask and contribute to improving the practical use of the high IWC mask.

Dispersive growth and laser-induced rippling of large-area singlelayer MoS2 nanosheets by CVD on c-plane sapphire substrate

PubMed Central

Liu, Hongfei; Chi, Dongzhi

2015-01-01

Vapor-phase growth of large-area two-dimensional (2D) MoS2 nanosheets via reactions of sulfur with MoO3 precursors vaporized and transferred from powder sources onto a target substrate has been rapidly progressing. Recent studies revealed that the growth yield of high quality singlelayer (SL) MoS2 is essentially controlled by quite a few parameters including the temperature, the pressure, the amount/weight of loaded source precursors, and the cleanup of old precursors. Here, we report a dispersive growth method where a shadow mask is encapsulated on the substrate to ‘indirectly’ supply the source precursors onto the laterally advancing growth front at elevated temperatures. With this method, we have grown large-area (up to millimeters) SL-MoS2 nanosheets with a collective in-plane orientation on c-plane sapphire substrates. Regular ripples (~1 nm in height and ~50 nm in period) have been induced by laser scanning into the SL-MoS2 nanosheets. The MoS2 ripples easily initiate at the grain boundaries and extend along the atomic steps of the substrate. Such laser-induced ripple structures can be fundamental materials for studying their effects, which have been predicted to be significant but hitherto not evidenced, on the electronic, mechanical, and transport properties of SL-MoS2. PMID:26119325

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

PubMed

Ramirez, Joel; O'Shaughnessy, Patrick

2017-02-01

The primary objective of this study was to compare the filter performance of a representative selection of uncertified dust masks relative to the filter performance of a set of NIOSH-approved N95 filtering face-piece respirators (FFRs). Five different models of commercially available dust masks were selected for this study. Filter penetration of new dust masks was evaluated against a sodium chloride aerosol. Breathing resistance (BR) of new dust masks and FFRs was then measured for 120 min while challenging the dust masks and FFRs with Arizona road dust (ARD) at 25°C and 30% relative humidity. Results demonstrated that a wide range of maximum filter penetration was observed among the dust masks tested in this study (3-75% at the most penetrating particle size (p < 0.001). The breathing resistances of the unused FFRs and dust masks did not vary greatly (8-13 mm H 2 O) but were significantly different (p < 0.001). After dust loading there was a significant difference between the BR caused by the ARD dust layer on each FFR and dust mask. Microscopic analysis of the external layer of each dust mask and FFR suggests that different collection media in the external layer influences the development of the dust layer and therefore affects the increase in BR differently between the tested models. Two of the dust masks had penetration values < 5% and quality factors (0.26 and 0.33) comparable to those obtained for the two FFRs (0.23 and 0.31). However, the remaining three dust masks, those with penetration > 15%, had quality factors ranging between 0.04-0.15 primarily because their initial BR remained relatively high. These results indicate that some dust masks analysed during this research did not have an expected very low BR to compensate for their high penetration.

Selective-area catalyst-free MBE growth of GaN nanowires using a patterned oxide layer.

PubMed

Schumann, T; Gotschke, T; Limbach, F; Stoica, T; Calarco, R

2011-03-04

GaN nanowires (NWs) were grown selectively in holes of a patterned silicon oxide mask, by rf-plasma-assisted molecular beam epitaxy (PAMBE), without any metal catalyst. The oxide was deposited on a thin AlN buffer layer previously grown on a Si(111) substrate. Regular arrays of holes in the oxide layer were obtained using standard e-beam lithography. The selectivity of growth has been studied varying the substrate temperature, gallium beam equivalent pressure and patterning layout. Adjusting the growth parameters, GaN NWs can be selectively grown in the holes of the patterned oxide with complete suppression of the parasitic growth in between the holes. The occupation probability of a hole with a single or multiple NWs depends strongly on its diameter. The selectively grown GaN NWs have one common crystallographic orientation with respect to the Si(111) substrate via the AlN buffer layer, as proven by x-ray diffraction (XRD) measurements. Based on the experimental data, we present a schematic model of the GaN NW formation in which a GaN pedestal is initially grown in the hole.

Ultra-High-Speed DNA Fragment Separations Using Microfabricated Capillary Array Electrophoresis Chips

NASA Astrophysics Data System (ADS)

Woolley, Adam T.; Mathies, Richard A.

1994-11-01

Capillary electrophoresis arrays have been fabricated on planar glass substrates by photolithographic masking and chemical etching techniques. The photolithographically defined channel patterns were etched in a glass substrate, and then capillaries were formed by thermally bonding the etched substrate to a second glass slide. High-resolution electrophoretic separations of φX174 Hae III DNA restriction fragments have been performed with these chips using a hydroxyethyl cellulose sieving matrix in the channels. DNA fragments were fluorescently labeled with dye in the running buffer and detected with a laser-excited, confocal fluorescence system. The effects of variations in the electric field, procedures for injection, and sizes of separation and injection channels (ranging from 30 to 120 μm) have been explored. By use of channels with an effective length of only 3.5 cm, separations of φX174 Hae III DNA fragments from ≈70 to 1000 bp are complete in only 120 sec. We have also demonstrated high-speed sizing of PCR-amplified HLA-DQα alleles. This work establishes methods for high-speed, high-throughput DNA separations on capillary array electrophoresis chips.

Silver decorated polymer supported semiconductor thin films by UV aided metalized laser printing

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

Halbur, Jonathan C.; Padbury, Richard P.; Jur, Jesse S., E-mail: jsjur@ncsu.edu

2016-05-15

A facile ultraviolet assisted metalized laser printing technique is demonstrated through the ability to control selective photodeposition of silver on flexible substrates after atomic layer deposition pretreatment with zinc oxide and titania. The photodeposition of noble metals such as silver onto high surface area, polymer supported semiconductor metal oxides exhibits a new route for nanoparticle surface modification of photoactive enhanced substrates. Photodeposited silver is subsequently characterized using low voltage secondary electron microscopy, x-ray diffraction, and time of flight secondary ion mass spectroscopy. At the nanoscale, the formation of specific morphologies, flake and particle, is highlighted after silver is photodeposited onmore » zinc oxide and titania coated substrates, respectively. The results indicate that the morphology and composition of the silver after photodeposition has a strong dependency on the morphology, crystallinity, and impurity content of the underlying semiconductor oxide. At the macroscale, this work demonstrates how the nanoscale features rapidly coalesce into a printed pattern through the use of masks or an X-Y gantry stage with virtually unlimited design control.« less

Comparison of desmoglein ELISA and indirect immunofluorescence using two substrates (monkey oesophagus and normal human skin) in the diagnosis of pemphigus.

PubMed

Ng, Patricia P L; Thng, Steven T G; Mohamed, Khatija; Tan, Suat Hoon

2005-11-01

A prospective study was performed to assess the usefulness of desmoglein enzyme-linked immunosorbent assay testing compared with indirect immunofluorescence in the diagnosis of new cases of pemphigus, as well as to compare the relative sensitivities of monkey oesophagus and normal human skin as substrates for indirect immunofluorescence. These tests were performed on the sera of 29 consecutive new cases of pemphigus diagnosed over a 2-year period based on clinical, histological and direct immunofluorescence findings. Desmoglein enzyme-linked immunosorbent assay was positive in all patients whereas indirect immunofluorescence was positive in only 25 of 29 patients. All four patients with negative indirect immunofluorescence had positive antinuclear antibodies or cytoplasmic fluorescence that could have masked the anti-intercellular antibodies. Desmoglein enzyme-linked immunosorbent assay appeared to reflect the disease activity better than indirect immunofluorescence in a few patients who had active disease of recent onset. Monkey oesophagus was found to be superior or equal to human skin as a substrate for indirect immunofluorescence in both pemphigus vulgaris and foliaceus.

Position-controlled MOVPE growth and electro-optical characterization of core-shell InGaN/GaN microrod LEDs

NASA Astrophysics Data System (ADS)

Schimpke, Tilman; Lugauer, H.-J.; Avramescu, A.; Varghese, T.; Koller, A.; Hartmann, J.; Ledig, J.; Waag, A.; Strassburg, M.

2016-03-01

Today's InGaN-based white LEDs still suffer from a significant efficiency reduction at elevated current densities, the so-called "Droop". Core-shell microrods, with quantum wells (QWs) covering their entire surface, enable a tremendous increase in active area scaling with the rod's aspect ratio. Enlarging the active area on a given footprint area is a viable and cost effective route to mitigate the droop by effectively reducing the local current density. Microrods were grown in a large volume metal-organic vapor phase epitaxy (MOVPE) reactor on GaN-on-sapphire substrates with a thin, patterned SiO2 mask for position control. Out of the mask openings, pencil-shaped n-doped GaN microrod cores were grown under conditions favoring 3D growth. In a second growth step, these cores are covered with a shell containing a quantum well and a p-n junction to form LED structures. The emission from the QWs on the different facets was studied using resonant temperature-dependent photoluminescence (PL) and cathodoluminescence (CL) measurements. The crystal quality of the structures was investigated by transmission electron microscopy (TEM) showing the absence of extended defects like threading dislocations in the 3D core. In order to fabricate LED chips, dedicated processes were developed to accommodate for the special requirements of the 3D geometry. The electrical and optical properties of ensembles of tens of thousands microrods connected in parallel are discussed.

Availability, consistency and evidence-base of policies and guidelines on the use of mask and respirator to protect hospital health care workers: a global analysis

PubMed Central

2013-01-01

Background Currently there is an ongoing debate and limited evidence on the use of masks and respirators for the prevention of respiratory infections in health care workers (HCWs). This study aimed to examine available policies and guidelines around the use of masks and respirators in HCWs and to describe areas of consistency between guidelines, as well as gaps in the recommendations, with reference to the WHO and the CDC guidelines. Methods Policies and guidelines related to mask and respirator use for the prevention of influenza, SARS and TB were examined. Guidelines from the World Health Organization (WHO), the Center for Disease Control and Prevention (CDC), three high-income countries and six low/middle-income countries were selected. Results Uniform recommendations are made by the WHO and the CDC in regards to protecting HCWs against seasonal influenza (a mask for low risk situations and a respirator for high risk situations) and TB (use of a respirator). However, for pandemic influenza and SARS, the WHO recommends mask use in low risk and respirators in high risk situations, whereas, the CDC recommends respirators in both low and high risk situations. Amongst the nine countries reviewed, there are variations in the recommendations for all three diseases. While, some countries align with the WHO recommendations, others align with those made by the CDC. The choice of respirator and the level of filtering ability vary amongst the guidelines and the different diseases. Lastly, none of the policies discuss reuse, extended use or the use of cloth masks. Conclusion Currently, there are significant variations in the policies and recommendations around mask and respirator use for protection against influenza, SARS and TB. These differences may reflect the scarcity of level-one evidence available to inform policy development. The lack of any guidelines on the use of cloth masks, despite widespread use in many low and middle-income countries, remains a policy gap. Health organizations and countries should jointly evaluate the available evidence, prioritize research to inform evidence gaps, and develop consistent policy on masks and respirator use in the health care setting. PMID:23725338

Availability, consistency and evidence-base of policies and guidelines on the use of mask and respirator to protect hospital health care workers: a global analysis.

PubMed

Chughtai, Abrar Ahmad; Seale, Holly; MacIntyre, Chandini Raina

2013-05-31

Currently there is an ongoing debate and limited evidence on the use of masks and respirators for the prevention of respiratory infections in health care workers (HCWs). This study aimed to examine available policies and guidelines around the use of masks and respirators in HCWs and to describe areas of consistency between guidelines, as well as gaps in the recommendations, with reference to the WHO and the CDC guidelines. Policies and guidelines related to mask and respirator use for the prevention of influenza, SARS and TB were examined. Guidelines from the World Health Organization (WHO), the Center for Disease Control and Prevention (CDC), three high-income countries and six low/middle-income countries were selected. Uniform recommendations are made by the WHO and the CDC in regards to protecting HCWs against seasonal influenza (a mask for low risk situations and a respirator for high risk situations) and TB (use of a respirator). However, for pandemic influenza and SARS, the WHO recommends mask use in low risk and respirators in high risk situations, whereas, the CDC recommends respirators in both low and high risk situations. Amongst the nine countries reviewed, there are variations in the recommendations for all three diseases. While, some countries align with the WHO recommendations, others align with those made by the CDC. The choice of respirator and the level of filtering ability vary amongst the guidelines and the different diseases. Lastly, none of the policies discuss reuse, extended use or the use of cloth masks. Currently, there are significant variations in the policies and recommendations around mask and respirator use for protection against influenza, SARS and TB. These differences may reflect the scarcity of level-one evidence available to inform policy development. The lack of any guidelines on the use of cloth masks, despite widespread use in many low and middle-income countries, remains a policy gap. Health organizations and countries should jointly evaluate the available evidence, prioritize research to inform evidence gaps, and develop consistent policy on masks and respirator use in the health care setting.

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

NASA Astrophysics Data System (ADS)

Buttgereit, Ute; Perlitz, Sascha

2009-03-01

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

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

NASA Technical Reports Server (NTRS)

Turner, B. J. (Principal Investigator)

1982-01-01

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

Development of Spatial Release from Masking in Mandarin-Speaking Children with Normal Hearing

ERIC Educational Resources Information Center

Yuen, Kevin C. P.; Yuan, Meng

2014-01-01

Purpose: This study investigated the development of spatial release from masking in children using closed-set Mandarin disyllabic words and monosyllabic words carrying lexical tones as test stimuli and speech spectrum-weighted noise as a masker. Method: Twenty-six children ages 4-9 years and 12 adults, all with normal hearing, participated in…

The Mask Designs for Space Interferometer Mission (SIM)

NASA Technical Reports Server (NTRS)

Wang, Xu

2008-01-01

The Space Interferometer Mission (SIM) consists of three interferometers (science, guide1, and guide2) and two optical paths (metrology and starlight). The system requirements for each interferometer/optical path combination are different and sometimes work against each other. A diffraction model is developed to design and optimize various masks to simultaneously meet the system requirements of three interferometers. In this paper, the details of this diffraction model will be described first. Later, the mask design for each interferometer will be presented to demonstrate the system performance compliance. In the end, a tolerance sensitivity study on the geometrical dimension, shape, and the alignment of these masks will be discussed.

Development of electrical-erosion instrument for direct write micro-patterning on large area conductive thin films

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

Álvarez, Ángel Luis; Coya, Carmen; García-Vélez, Miguel

2015-08-15

We have developed a complete instrument to perform direct, dry, and cost-effective lithography on conductive materials, based on localized electrical discharges, which avoids using masks or chemicals typical of conventional photolithography. The technique is considered fully compatible with substrate transport based systems, like roll-to-roll technology. The prototype is based on two piezo nano-steppers coupled to three linear micro-stages to cover a large scale operation from micrometers to centimeters. The operation mode consists of a spring probe biased at low DC voltage with respect to a grounded conductive layer. The tip slides on the target layer keeping contact with the materialmore » in room conditions, allowing continuous electric monitoring of the process, and also real-time tilt correction via software. The sliding tip leaves an insulating path (limited by the tip diameter) along the material, enabling to draw electrically insulated tracks and pads. The physical principle of operation is based in the natural self-limitation of the discharge due to material removal or insulation. The so produced electrical discharges are very fast, in the range of μs, so features may be performed at speeds of few cm/s, enabling scalability to large areas. The instrument has been tested on different conducting materials as gold, indium tin oxide, and aluminum, allowing the fabrication of alphanumeric displays based on passive matrix of organic light emitting diodes without the use of masks or photoresists. We have verified that the highest potential is achieved on graphene, where no waste material is detected, producing excellent well defined edges. This allows manufacturing graphene micro-ribbons with a high aspect ratio up to 1200:1.« less

Development of electrical-erosion instrument for direct write micro-patterning on large area conductive thin films

NASA Astrophysics Data System (ADS)

Álvarez, Ángel Luis; Coya, Carmen; García-Vélez, Miguel

2015-08-01

We have developed a complete instrument to perform direct, dry, and cost-effective lithography on conductive materials, based on localized electrical discharges, which avoids using masks or chemicals typical of conventional photolithography. The technique is considered fully compatible with substrate transport based systems, like roll-to-roll technology. The prototype is based on two piezo nano-steppers coupled to three linear micro-stages to cover a large scale operation from micrometers to centimeters. The operation mode consists of a spring probe biased at low DC voltage with respect to a grounded conductive layer. The tip slides on the target layer keeping contact with the material in room conditions, allowing continuous electric monitoring of the process, and also real-time tilt correction via software. The sliding tip leaves an insulating path (limited by the tip diameter) along the material, enabling to draw electrically insulated tracks and pads. The physical principle of operation is based in the natural self-limitation of the discharge due to material removal or insulation. The so produced electrical discharges are very fast, in the range of μs, so features may be performed at speeds of few cm/s, enabling scalability to large areas. The instrument has been tested on different conducting materials as gold, indium tin oxide, and aluminum, allowing the fabrication of alphanumeric displays based on passive matrix of organic light emitting diodes without the use of masks or photoresists. We have verified that the highest potential is achieved on graphene, where no waste material is detected, producing excellent well defined edges. This allows manufacturing graphene micro-ribbons with a high aspect ratio up to 1200:1.

Development of electrical-erosion instrument for direct write micro-patterning on large area conductive thin films.

PubMed

Álvarez, Ángel Luis; Coya, Carmen; García-Vélez, Miguel

2015-08-01

We have developed a complete instrument to perform direct, dry, and cost-effective lithography on conductive materials, based on localized electrical discharges, which avoids using masks or chemicals typical of conventional photolithography. The technique is considered fully compatible with substrate transport based systems, like roll-to-roll technology. The prototype is based on two piezo nano-steppers coupled to three linear micro-stages to cover a large scale operation from micrometers to centimeters. The operation mode consists of a spring probe biased at low DC voltage with respect to a grounded conductive layer. The tip slides on the target layer keeping contact with the material in room conditions, allowing continuous electric monitoring of the process, and also real-time tilt correction via software. The sliding tip leaves an insulating path (limited by the tip diameter) along the material, enabling to draw electrically insulated tracks and pads. The physical principle of operation is based in the natural self-limitation of the discharge due to material removal or insulation. The so produced electrical discharges are very fast, in the range of μs, so features may be performed at speeds of few cm/s, enabling scalability to large areas. The instrument has been tested on different conducting materials as gold, indium tin oxide, and aluminum, allowing the fabrication of alphanumeric displays based on passive matrix of organic light emitting diodes without the use of masks or photoresists. We have verified that the highest potential is achieved on graphene, where no waste material is detected, producing excellent well defined edges. This allows manufacturing graphene micro-ribbons with a high aspect ratio up to 1200:1.