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Masking Meaning

Description: Chapter I describes the purpose of the project, which was to develop a body of work that exhibits my current thought process. The questions presented to myself consisted of the following: 1. How effective was the expression of my ideas socially and politically after the change to the work? 2. Was the minimal approach a tool that contributes or detracts from this effectiveness? 3. Did an increase in scale successfully act as an element of confrontation? Chapter II describes the inspiration behind the making of my work it also discusses problems encountered with an understanding of the viewer concerning imagery. Chapter III summarizes the methodology behind the execution of the new body of work. It also discusses how simplification of imagery works as a solution to my problems.
Date: May 2003
Creator: Allee, Jake R.
Partner: UNT Libraries

The Effects of a Masking Noise Upon the Performance of a Simple Motor Task Comparing Brain-Injured and Non-Brain-Injured Children

Description: Two questions can be posed for study: 1) Will the effect of auditory masking provided by a clinical noise significantly affect the performance of hearing children on the Knox Cube Test? 2) Are there significant differences among brain-injured, mentally, retarded, and "normal" children in ability to adjust to auditory masking in the performance of the Knox Cube Test?
Date: August 1967
Creator: Moss, Barbara A.
Partner: UNT Libraries

Environmentally friendly polysilane photoresists

Description: Several novel polysilanes synthesized by the free-radical hydrosilation of oligomeric polyphenylsilane or poly(p-tert- butylphenylsilane) were examined for lithographic behavior. This recently developed route into substituted polysilanes has allowed for the rational design of a variety of polysilanes with a typical chemical properties such as alcohol and aqueous base solubility. Many of the polysilane resists made could be developed in aqueous sodium carbonate and bicarbonate solutions. These materials represent environmentally friendly polysilane resists in both their synthesis and processing.
Date: December 31, 1995
Creator: Beach, J.V.; Loy, D.A.; Hsiao, Yu-Ling & Waymouth, R.M.
Partner: UNT Libraries Government Documents Department

SEMATECH EUV resist benchmarking results

Description: Extreme Ultraviolet Lithography (EUVL) is one of the leading candidates for next generation lithography technology for the 32 nm HP and beyond. The availability of EUV resists is one of the most significant challenges facing its commercialization. To accelerate EUV resist development, SEMATECH provides access to two exposure tools: (1) The EUV Resist Test Center (RTC) at SEMATECH at the University at Albany, SUNY, NY; and (2) the SEMATECH microexposure tools (ALS-MET) at Lawrence Berkeley National Laboratory (LBNL).
Date: October 27, 2007
Creator: Ma, Andy; Park, Joo-On; Dean, Kim; Wurm, Stefan & Naulleau, Patrick
Partner: UNT Libraries Government Documents Department

A high-throughput contact-hole resolution metric for photoresists:Full-process sensitivity study

Description: The ability to accurately quantify the intrinsic resolution of chemically amplified photoresists is critical for the optimization of resists for extreme ultraviolet (EUV) Iithography. We have recently reported on two resolution metrics that have been shown to extract resolution numbers consistent with direct observation. In this paper we examine the previously reported contact-hole resolution metric and explore the sensitivity of the metric to potential error sources associated with the experimental side of the resolution extraction process. For EUV exposures at the SEMATECH Berkeley microfield exposure tool, we report a full-process error-bar in extracted resolution of 1.75 nm RMS and verify this result experimentally.
Date: January 22, 2008
Creator: Anderson, Christopher N. & Naulleau, Patrick P.
Partner: UNT Libraries Government Documents Department

Conveyorized Photoresist Stripping Replacement for Flex Circuit Fabrication

Description: A replacement conveyorized photoresist stripping system was characterized to replace the ASI photoresist stripping system. This system uses the qualified ADF-25c chemistry for the fabrication of flex circuits, while the ASI uses the qualified potassium hydroxide chemistry. The stripping process removes photoresist, which is used to protect the copper traces being formed during the etch process.
Date: February 24, 2009
Creator: Donahue, Megan
Partner: UNT Libraries Government Documents Department

Deprotection blue in extreme ultraviolet photoresists: influence of base loading and post-exposure bake temperture

Description: The deprotection blur of Rohm and Haas XP 5435, XP 5271, and XP5496 extreme ultraviolet photoresists has been determined as their base weight percent is varied. They have also determined the deprotection blur of TOK EUVR P1123 photoresist as the post-exposure bake temperature is varied from 80 C to 120 C. In Rohm and Haas XP 5435 and XP5271 resists 7x and 3x (respective) increases in base weight percent reduce the size of successfully patterned 1:1 line-space features by 16 nm and 8 nm with corresponding reductions in deprotection blur of 7 nm and 4 nm. In XP 5496 a 7x increase in base weight percent reduces the size of successfully patterned 1:1 line-space features from 48 nm to 38 nm without changing deprotection blur. In TOK EUVR P1123 resist, a reduction in post-exposure bake temperature from 100 C to 80 C reduces deprotection blur from 21 nm to 10 nm and reduces patterned LER from 4.8 nm to 4.1 nm.
Date: June 2, 2008
Creator: Anderson, Christopher N. & Naulleau, Patrick P.
Partner: UNT Libraries Government Documents Department

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

Description: In the case of extreme ultraviolet (EUV) lithography, modeling has shown that reflector phase roughness on the lithographic mask is a significant concern due to the image plan speckle it causes and the resulting line-edge roughness on imaged features. Modeling results have recently been used to determine the requirements for future production worthy masks yielding the extremely stringent specification of 50 pm rms roughness. Owing to the scale of the problem in terms of memory requirements, past modeling results have all been based on the thin mask approximation. EUV masks, however, are inherently three dimensional in nature and thus the question arises as to the validity of the thin mask approximation. Here we directly compare image plane speckle calculation results using the fast two dimensional thin mask model to rigorous finite-difference time-domain results and find the two methods to be comparable.
Date: January 26, 2011
Creator: Naulleau, Patrick & George, Simi
Partner: UNT Libraries Government Documents Department

ICP Etching of SiC

Description: A number of different plasma chemistries, including NF{sub 3}/O{sub 2}, SF{sub 6}/O{sub 2}, SF{sub 6}/Ar, ICl, IBr, Cl{sub 2}/Ar, BCl{sub 3}/Ar and CH{sub 4}/H{sub 2}/Ar, have been investigated for dry etching of 6H and 3C-SiC in a Inductively Coupled Plasma tool. Rates above 2,000 {angstrom} cm{sup {minus}1} are found with fluorine-based chemistries at high ion currents. Surprisingly, Cl{sub 2}-based etching does not provide high rates, even though the potential etch products (SiCi{sub 4} and CCl{sub 4}) are volatile. Photoresist masks have poor selectivity over SiC in F{sub 2}-based plasmas under normal conditions, and ITO or Ni are preferred.
Date: February 4, 1999
Creator: Grow, J.M.; Lambers, E.S.; Ostling, M.; Pearton, S.J.; Ren, F.; Shul, R.J. et al.
Partner: UNT Libraries Government Documents Department

Masks for extreme ultraviolet lithography

Description: In extreme ultraviolet lithography (EUVL), the technology specific requirements on the mask are a direct consequence of the utilization of radiation in the spectral region between 10 and 15 nm. At these wavelengths, all condensed materials are highly absorbing and efficient radiation transport mandates the use of all-reflective optical systems. Reflectivity is achieved with resonant, wavelength-matched multilayer (ML) coatings on all of the optical surfaces - including the mask. The EUV mask has a unique architecture - it consists of a substrate with a highly reflective ML coating (the mask blank) that is subsequently over-coated with a patterned absorber layer (the mask). Particulate contamination on the EUVL mask surface, errors in absorber definition and defects in the ML coating all have the potential to print in the lithographic process. While highly developed technologies exist for repair of the absorber layer, no viable strategy for the repair of ML coating defects has been identified. In this paper the state-of-the-art in ML deposition technology, optical inspection of EUVL mask blank defects and candidate absorber patterning approaches are reviewed.
Date: September 1, 1998
Creator: Cardinale, G; Goldsmith, J; Kearney, P A; Larson, C; Moore, C E; Prisbrey, S et al.
Partner: UNT Libraries Government Documents Department

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

Description: The readiness of a defect-free extreme ultraviolet lithography (EUVL) mask blank infrastructure is one of the main enablers for the insertion of EUVL technology into production. It is essential to have sufficient defect detection capability and understanding of defect printability to develop a defect-free EUVL mask blank infrastructure. The SEMATECH Mask Blank Development Center (MBDC) has been developing EUVL mask blanks with low defect densities with the Lasertec M1350 and M7360, the 1st and 2nd generations, respectively, of visible light EUVL mask blank inspection tools. Although the M7360 represents a significant improvement in our defect detection capability, it is time to start developing a 3rd generation tool for EUVL mask blank inspection. The goal of this tool is to detect all printable defects; therefore, understanding defect printability criteria is critical to this tool development. In this paper, we will investigate the defect detectability of a 2nd generation blank inspection tool and a patterned EUVL mask inspection tool. We will also compare the ability of the inspection tools to detect programmed defects whose printability has been estimated from wafer printing results and actinic aerial images results.
Date: August 1, 2007
Creator: Cho, Wonil; Han, Hak-Seung; Goldberg, Kenneth A.; Kearney,Patrick A. & Jeon, Chan-Uk
Partner: UNT Libraries Government Documents Department

Extreme Ultraviolet Phase Contrast Imaging

Description: The conclusions of this report are: (1) zone plate microscopy provides high resolution imaging of EUV masks; (2) using phase plates in the back focal plane of the objective lens can provide contrast mechanisms for measurement of the phase shift from defects on the mask; (3) the first high resolution EUV Zernike phase contrast images have been acquired; and (4) future work will include phase contrast mode in reflection from an EUV mask to directly measure the reflectivity and phase shift from defects.
Date: November 1, 2005
Creator: Denbeaux, Gregory; Garg, Rashi; Aquila, Andy; Barty, Anton; Goldberg, Kenneth; Gullikson, Eric et al.
Partner: UNT Libraries Government Documents Department

Growth and Printability of Multilayer Phase Defects on EUV MaskBlanks

Description: The ability to fabricate defect-free mask blanks is a well-recognized challenge in enabling extreme ultraviolet lithography (EUVL) for semiconductor manufacturing. Both the specification and reduction of defects necessitate the understanding of their printability and how they are generated and grow during Mo-Si multilayer (ML) deposition. A ML phase defect can be depicted by its topographical profile on the surface as either a bump or pit, which is then characterized by height or depth and width. The complexity of such seemingly simple phase defects lies in the many ways they can be generated and the difficulties of measuring their physical shape/size and optical effects on printability. An effective way to study phase defects is to use a programmed defect mask (PDM) as 'model' test sample where the defects are produced with controlled growth on a ML blank and accurate placement in varying proximity to absorber patterns on the mask. This paper describes our recent study of ML phase defect printability with resist data from exposures of a ML PDM on the EUV micro-exposure tool (MET, 5X reduction with 0.3NA).
Date: June 10, 2007
Creator: Liang, Ted; Ultanir, Erdem; Zhnag, Guojing; Park, Seh-Jin; Anderson, Erik; Gullikson, Eric et al.
Partner: UNT Libraries Government Documents Department

LIGA-based microsystem manufacturing:the electrochemistry of through-mold depostion and material properties.

Description: The report presented below is to appear in ''Electrochemistry at the Nanoscale'', Patrik Schmuki, Ed. Springer-Verlag, (ca. 2005). The history of the LIGA process, used for fabricating dimensional precise structures for microsystem applications, is briefly reviewed, as are the basic elements of the technology. The principal focus however, is on the unique aspects of the electrochemistry of LIGA through-mask metal deposition and the generation of the fine and uniform microstructures necessary to ensure proper functionality of LIGA components. We draw from both previously published work by external researchers in the field as well as from published and unpublished studies from within Sandia.
Date: June 1, 2005
Creator: Kelly, James J. (Sandia National Laboratories, Livermore, CA) & Goods, Steven Howard (Sandia National Laboratories, Livermore, CA)
Partner: UNT Libraries Government Documents Department

Automated mask creation from a 3D model using Faethm.

Description: We have developed and implemented a method which given a three-dimensional object can infer from topology the two-dimensional masks needed to produce that object with surface micro-machining. The masks produced by this design tool can be generic, process independent masks, or if given process constraints, specific for a target process. This design tool calculates the two-dimensional mask set required to produce a given three-dimensional model by investigating the vertical topology of the model.
Date: November 1, 2007
Creator: Schiek, Richard Louis & Schmidt, Rodney Cannon
Partner: UNT Libraries Government Documents Department

Recent results from the Berkeley 0.3-NA microfield exposure tool

Description: Operating as a SEMATECH resist test center, the Berkeley 0.3-NA EUV microfield exposure tool continues to play a crucial role in the advancement of EUV resists and masks. Here we present recent resist-characterization results from the tool as well as tool-characterization data. In particular we present lithographic-based aberration measurements demonstrating the long-term stability of the tool. We also describe a recent upgrade to the tool which involved redesign of the programmable coherence illuminator to provide improved field uniformity as well as a programmable field size.
Date: March 1, 2007
Creator: Naulleau, Patrick; Anderson, Christopher N.; Dean, Kim; Denham, Paul; Goldberg, Kenneth A.; Hoef, Brian et al.
Partner: UNT Libraries Government Documents Department

Molecular Dynamics Simulation of Polymer Dissolution

Description: In the LIGA process for manufacturing microcomponents, a polymer film is exposed to an x-ray beam passed through a gold pattern. This is followed by the development stage, in which a selective solvent is used to remove the exposed polymer, reproducing the gold pattern in the polymer film. Development is essentially polymer dissolution, a physical process which is not well understood. We have used coarse-grained molecular dynamics simulation to study the early stage of polymer dissolution. In each simulation a film of non-glassy polymer was brought into contact with a layer of solvent. The mutual penetration of the two phases was tracked as a function of time. Several film thicknesses and two different chain lengths were simulated. In all cases, the penetration process conformed to ideal Fickian diffusion. We did not see the formation of a gel layer or other non-ideal effects. Variations in the Fickian diffusivities appeared to be caused primarily by differences in the bulk polymer film density.
Date: February 1, 2003
Partner: UNT Libraries Government Documents Department

Deep x-ray lithography based processing for micromechanics

Description: Deep x-ray lithography based fabrication provides a means to fabricate microactuators with useful output forces. High energy x-ray exposure provides a tool for fabrication of the next generation of precision engineered components. Device characterization, materials science, an metrology continue to pose challenges at this scale.
Date: October 1995
Creator: Christenson, T. R.
Partner: UNT Libraries Government Documents Department

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

Description: The mask is deemed one of the areas that require significant research and development in EUVL. Silicon wafers will be used for mask substrates for an alpha-class EUVL exposure tool due to their low-defect levels and high quality surface finish. However, silicon has a large coefficient of thermal expansion that leads to unacceptable image distortion due to absorption of EUV light. A low thermal expansion glass or glass-ceramic is likely to be required in order to meet error budgets for the 70nm node and beyond. Since EUVL masks are used in reflection, they are coated with multilayers prior to patterning. Surface imperfections, such as polishing marks, particles, scratches, or digs, are potential nucleation sites for defects in the multilayer coating, which could result in the printed defects. Therefore we are accelerating developments in the defect reduction and surface finishing of low thermal expansion mask substrates in order to understand long-term issues in controlling printable defects, and to establish the infrastructure for supplying masks. In this paper, we explain the technical requirements for EUVL mask substrates and describe our efforts in establishing a SEMI standard for EUVL masks. We will also report on the early progress of our suppliers in producing low thermal-expansion mask substrates for our development activities.
Date: September 28, 1999
Creator: Hector, S D; Shell, M; Taylor, J S & Tong, W M
Partner: UNT Libraries Government Documents Department

Cryogenic xenon droplets for advanced lithography

Description: A cryogenic xenon droplet production system for use in anadvanced laser plasma source for x-ray lithography has been designed, fabricated, and tested at ORNL. The droplet generator is based on proven (ink jet printer) drop-on-demand.
Date: April 1, 1996
Creator: Gouge, M.J. & Fisher, P.W.
Partner: UNT Libraries Government Documents Department