Dr. Dirk Pfeiffer Profile

Dr. Dirk Pfeiffer

Research Staff Member at IBM Thomas J Watson Research Ctr

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Publications (8)

Proceedings Article | 26 March 2008 Paper

Graded spin-on organic bottom antireflective coating for high NA lithography

Dario Goldfarb, Sean Burns, Libor Vyklicky, Dirk Pfeiffer, Anthony Lisi, Karen Petrillo, John Arnold, Daniel Sanders, Aleksandra Clancy, Robert Lang, Robert Allen, David Medeiros, Dah Chung Owe-Yang, Kazumi Noda, Seiichiro Tachibana, Shozo Shirai

Proceedings Volume 6923, 69230V (2008) https://doi.org/10.1117/12.772268

KEYWORDS: Reflectivity, Polymers, Photoresist materials, Silicon, Etching, Lithography, Optical lithography, Interfaces, Multilayers, Semiconducting wafers

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Proceedings Article | 27 March 2007 Paper

Global optimization of masks, including film stack design to restore TM contrast in high NA TCC's

Alan Rosenbluth, David Melville, Kehan Tian, Kafai Lai, Nakgeuon Seong, Dirk Pfeiffer, Matthew Colburn

Proceedings Volume 6520, 65200P (2007) https://doi.org/10.1117/12.713050

KEYWORDS: Photomasks, Lithography, Source mask optimization, Optimization (mathematics), Diffraction, Reflectivity, Wavefronts, Binary data, Tolerancing, Optical proximity correction

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We provide an expanded description of the global algorithm for mask optimization introduced in our earlier papers, and discuss auxiliary optimizations that can be carried out in the problem constraints and film stack. Mask optimization tends inherently to be a problem with non-convex quadratic constraints, but for small problems we can mitigate this difficulty by exploiting specialized knowledge that applies in the lithography context. If exposure latitude is approximated as maximization of edge slope between image regions whose intensities must print with opposite polarity, we show that the solution space can be approximately divided into regions that contain at most one local minimum. Though the survey of parameter space to identify these regions requires an exhaustive grid search, this search can be accelerated using heuristics, and is not the rate-limiting step at SRAM scale or below. We recover a degree of generality by using a less simplified objective function when we actually assess the local minima. The quasi-binary specialization of lithographic targets is further exploited by searching only in the subspace formed by the dominant joint eigenvectors for dark region intensity and bright region intensity, typically reducing problem dimensionality to less than half that of the full set of frequency-domain variables (i.e. collected diffraction orders). Contrast in this subspace across the bright/dark edge will approximately reflect exposure latitude when we apply the standard fixed edge-placement constraints of lithography. However, during an exploratory stage of optimization we can define preliminary tolerances which more explicitly reflect constraints on devices, e.g. as is done with compactor codes for design migration. Our algorithm can handle vector imaging in a general way, but for the special case of unpolarized illumination and a lens having radial symmetry (but arbitrary source shape) we show that the bilinear function which describes vector interference within the film stack can be expressed in terms of three generic radial functions, enabling rapid numerical evaluation of the Hopkins kernel. By inspection these functions show that one can in principle recover classical scalar-like imaging even at high NA by exposing a very thin layer spaced above a reflective substack. The reflected image largely restores destructive interference in TM polarized fringes, if proper phasing is achieved. With an ideal reflector, the first-order azimuthal contrast loss term vanishes in all TCC components, and complete equivalence to scalar imaging is obtained in classical two-beam imaging.

Proceedings Article | 29 March 2006 Paper

Silicon containing polymer in applications for 193-nm high-NA lithography processes

Sean Burns, Dirk Pfeiffer, Arpan Mahorowala, Karen Petrillo, Alexandera Clancy, Katherina Babich, David Medeiros, Scott Allen, Steven Holmes, Michael Crouse, Colin Brodsky, Victor Pham, Yi-Hsiung Lin, Kaushal Patel, Naftali Lustig, Allen Gabor, Christopher Sheraw, Phillip Brock, Carl Larson

Proceedings Volume 6153, 61530K (2006) https://doi.org/10.1117/12.657197

KEYWORDS: Silicon, Reflectivity, Etching, Photoresist materials, Polymers, Lithography, Oxides, Silicon films, Reactive ion etching, Optical lithography

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Proceedings Article | 4 May 2005 Paper

Silsesquioxane-based 193 nm bilayer resists: characterization and lithographic evaluation

Hiroshi Ito, Hoa Truong, Sean Burns, Dirk Pfeiffer, Wu-Song Huang, Mahmoud Khojasteh, P. Rao Varanasi, Mike Lercel

Proceedings Volume 5753, (2005) https://doi.org/10.1117/12.598847

KEYWORDS: Polymers, Silicon, Etching, Lithography, Monochromatic aberrations, Resistance, FT-IR spectroscopy, Quartz, Crystals, Spectroscopy

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Polysilsesquioxane-based 193 nm positive bilayer resists are described. In this design Si for etch resistance is placed in every repeat unit and acid-labile protected and acidic groups (and polar units) are in the side chain, allowing to incorporate each lithographically critical functionality in sufficient quantity. Fluoroalcohol is employed as an acid group instead of carboxylic acid because of its more attractive dissolution properties. Polymers were carefully analyzed by ¹⁹F, ¹³C, and ²⁹Si NMR to determine composition and to quantify residual acetyl, silanol, and Q/T. Hydrogen-bonding between tertiary ester and fluoroalcohol in the polysilsesquioxanes was investigated by FT-IR and the effect of lactone incorporation on the thermal deprotection temperature elucidated. In order to better understand the dissolution behavior of exposed resist films, the silsesquioxane resist polymers were partially (ca. 30%) and fully deprotected in solution with acid and their dissolution kinetics investigated by using a quartz crystal microbalance (QCM). It has been found that the exposed areas of the silsesquioxane resists can have a very fast dissolution rate (R_max) of >20,000 A/sec (or even >100,000 A/sec). Heating the fully deprotected model polymers to 150°C did not reduce the dissolution rate much, suggesting thermal condensation of silanol end groups is insignificant. Model deprotected polymers containing triphenylsulfonium nonaflate were exposed to 254 nm radiation, baked, and subjected to QCM measurements in order to determine whether or not acid-catalyzed silanol condensation would reduce the dissolution rate. A combination of high dose and high temperature bake resulted in significant reduction of the dissolution rate in the silsesquioxane polymer containing a small trifluoroalcohol. However, the dissolution behavior of the polymer bearing a bulky norbornene hexafluoroalcohol was unaffected by exposure and bake. Chemical and development contrast curves were generated by using a temperature gradient plate and bake temperature effects investigated. While a postapply bake temperature variation from 95 to 130°C did not affect the contrast (chemical and development) and sensitivity, a postexposure bake temperature effect was quite small. The process window of the silsesquioxane bilayer resists was comparable to that of a high performance commercial 193 nm single layer resist for both isolated and nested contact hole imaging, Superior performance of our silsesquioxane resist was demonstrated in patterned etch in comparison with a COMA-based bilayer resist.

Proceedings Article | 4 May 2005 Paper

Molecular resists based on polyhedral oligomeric silsesquioxanes (POSS)

Ratnam Sooriyakumaran, Hoa Truong, Linda Sundberg, Mark Morris, Bill Hinsberg, Hiroshi Ito, Robert Allen, Wu-Song Huang, Dario Goldfarb, Sean Burns, Dirk Pfeiffer

Proceedings Volume 5753, (2005) https://doi.org/10.1117/12.600615

KEYWORDS: Silicon, Line edge roughness, Polymers, Glasses, Standards development, Diffusion, Lithography, Spectroscopy, Macromolecules, Chemically amplified resists

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Proceedings Article | 12 June 2003 Paper

Highly etch-selective spin-on bottom antireflective coating for use in 193-nm lithography and beyond

Dirk Pfeiffer, Arpan Mahorowala, Katherina Babich, David Medeiros, Karen Petrillo, Marie Angelopoulos, Wu-Song Huang, Scott Halle, Colin Brodsky, Scott Allen, Steven Holmes, Ranee Kwong, Robert Lang, Phillip Brock

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485178

KEYWORDS: Silicon, Etching, Lithography, Polymers, Oxides, Photoresist processing, Reflectivity, Silicon films, 193nm lithography, Bottom antireflective coatings

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Proceedings Article | 12 June 2003 Paper

Hardmask technology for sub-100-nm lithographic imaging

Katherina Babich, Arpan Mahorowala, David Medeiros, Dirk Pfeiffer, Karen Petrillo, Marie Angelopoulos, Alfred Grill, Vishnubhai Patel, Scott Halle, Timothy Brunner, Richard Conti, Scott Allen, Richard Wise

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485174

KEYWORDS: Etching, Silicon, Reflectivity, Lithography, Plasma, Interfaces, Photoresist processing, Electron beam lithography, Plasma enhanced chemical vapor deposition, Image resolution

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Proceedings Article | 12 June 2003 Paper

Impact of thin resist processes on post-etch LER

Arpan Mahorowala, Dario Goldfarb, Karen Temple, Karen Petrillo, Dirk Pfeiffer, Katherina Babich, Marie Angelopoulos, Gregg Gallatin, Stacy Rasgon, Herbert Sawin, Scott Allen, Robert Lang, Margaret Lawson, Ranee Kwong, Kuang-Jung Chen, Wenjie Li, Pushkara Varanasi, Martha Sanchez, Hiroshi Ito, Gregory Wallraff, Robert Allen

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485168

KEYWORDS: Etching, Oxides, Scanning electron microscopy, Line edge roughness, Atomic force microscopy, Polymers, Plasma, Plasma etching, Chemistry, Photoresist processing

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Showing 5 of 8 publications

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