Dr. C. Grant Willson Profile

Dr. C. Grant Willson

at Univ of Texas at Austin

SPIE Involvement:

Author | Instructor

Publications (157)

Proceedings Article | 25 March 2019 Presentation + Paper

Defect mitigation in sub-20nm patterning with high-chi, silicon-containing block copolymers

Jan Doise, Geert Mannaert, Hyo Seon Suh, Paulina Rincon, Jai Hyun Koh, Ji Yeon Kim, Qingjun Zhu, Geert Vandenberghe, C. Grant Willson, Christopher Ellison

Proceedings Volume 10960, 109600Y (2019) https://doi.org/10.1117/12.2515176

KEYWORDS: Optical lithography, Silicon

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Proceedings Article | 25 March 2019 Presentation

Design of selective brush chemistry and surface functionalization for directed self-assembly of block copolymers (Conference Presentation)

Ji Yeon Kim, Natsuko Ito, XiaoMin Yang, Stephen Sirard, Austin Lane, Gregory Blachut, Yusuke Asano, Christopher Ellison, Nathaniel Lynd, C. Grant Willson

Proceedings Volume 10960, 109600S (2019) https://doi.org/10.1117/12.2514793

KEYWORDS: Directed self assembly, Chromium, Chemistry, Polymers, Photomasks, High volume manufacturing, Manufacturing, Nanoimprint lithography, Lithography, Photoresist processing

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Proceedings Article | 25 March 2019 Presentation

Pitch division photolithography at I-line (Conference Presentation)

Paul Meyer, Ji Yeon Kim, Nathaniel Lynd, C. Grant Willson

Proceedings Volume 10960, 109600J (2019) https://doi.org/10.1117/12.2514762

KEYWORDS: Optical lithography, Photoresist materials, Polymers, Photoresist developing, Image resolution, Astatine

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This project, “Pitch Division Photolithography at I-line,” seeks to accomplish pitch multiplication by using a traditional 248 nm photoresist polymer in conjunction with a photo-acid generator (PAG) and a photo-base generator (PBG). This formulation can achieve a two-fold improvement in resolution without the need for new equipment or significant changes in processing conditions. The photoresist matrix used in this work is poly[4-[(tert-butoxycarbonyl)oxy] styrene] (PTBOC), which is employed in combination with a PAG in 248 nm resists. When exposed to light, the PAG decomposes to form acid which, upon post-exposure baking, deprotects multiple pendant groups on the PTBOC to produce hydroxyl groups, thereby changing its solubility. This polymer exhibits another key feature: the dissolution rate with respect to dose has a threshold-like response, meaning that below a threshold dose, the polymer will not appreciably dissolve in a developer containing tetramethyl ammonium hydroxide (TMAH), but above this dose, the dissolution rate increases several orders of magnitude. This behavior becomes vital at feature sizes that approach theoretical resolution limits where the aerial image near the photoresist becomes more sinusoidal. Because the dissolution rate is controlled by the acid content within the polymer matrix, it is possible to cross this dissolution threshold twice with increasing dose if the acid is somehow quenched at higher doses. A PBG is an easy way to achieve this goal. If a PBG is chosen such that it is decomposes more slowly than the PAG and is incorporated with a stochiometric excess, then this dissolution threshold may be crossed twice. The addition of a PBG generates three different regimes with respect to dose: At low doses, neither the PAG nor PBG will have appreciably decomposed and the resist remains insoluble in aqueous base. At medium doses, enough acid will be generated by the PAG to cross the threshold, with too little PBG decomposition to effectively quench said acid. At high doses, both the PAG and PBG have mostly decomposed and the net acid concentration will be below the dissolution threshold. If the relative rates of the PAG and PBG can be tuned such that these two dissolution thresholds properly match the sinusoid intensity profile, the resolution of patterns can be improved by a factor of two. Dr. Xinyu Gu previously demonstrated the feasibility of such a system for 193 nm tools [1]. In this work, we report several combinations of PAGs and PBGs that meet the above criteria and show promise for exhibiting pitch-division. In some cases, a photosensitizer was needed to enable the decomposition of the PAG. These combinations were tested by exposing a film to a given dose and then developing in an aqueous solution of TMAH. It was found that the relative dissolution rates closely match the ideals as described above. These combinations are ready for testing with an exposure tool to verify and optimize their function as a pitch division photoresist. Reference: [1] Gu, X. et al. “Photobase generator enabled pitch division: a progress report,” Proc. SPIE 7972, 79720F (2011).

Proceedings Article | 22 March 2018 Paper

Evolution of roughness during the pattern transfer of high-chi, 10nm half-pitch, silicon-containing block copolymer structures

Gregory Blachut, Stephen Sirard, Andrew Liang, Chris Mack, Michael Maher, Paulina Rincon-Delgadillo, Boon Teik Chan, Geert Mannaert, Geert Vandenberghe, C. Grant Willson, Christopher Ellison, Diane Hymes

Proceedings Volume 10589, 1058907 (2018) https://doi.org/10.1117/12.2297489

KEYWORDS: Etching, Silicon, Chemistry, Reactive ion etching, Directed self assembly, Semiconducting wafers, Dry etching, Scanning electron microscopy, Line edge roughness

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Proceedings Article | 19 March 2018 Presentation

Block copolymers for sub-10nm directed self-assembly lithography (Conference Presentation)

Natsuko Ito, Gregory Blachut, Yusuke Asano, Christopher Ellison, Grant Willson, Stephen Sirard, XiaoMin Yang, Austin Lane

Proceedings Volume 10584, 105840J (2018) https://doi.org/10.1117/12.2297030

KEYWORDS: Directed self assembly, Lithography, Silicon, Polymerization, Silicon films, Reactive ion etching, Thin films, Photomasks, Thin film coatings, Chemistry

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Directed self-assembly (DSA) of block co-polymers (BCPs) is a next-generation lithography technique that shows promise for extending Moore’s Law into the 10 nm regime and below. The minimum size of the features that can be produced by BCPs is controlled by the interaction parameter (chi) and the degree of polymerization (N). We have developed silicon containing BCPs for sub-20 nm line-and-space lithography. These BCPs were synthesized by living anionic polymerization, thermally annealed in thin films between neutral layers to generate the requisite perpendicular orientation [1, 2]. The silicon-containing blocks provide excellent development contrast under both oxidizing and reducing reactive ion etching (RIE) conditions. The developed patterns work well as masks for transfer of the developed patterns into useful substrate materials [3]. Through optimizing the design of the block copolymers and the “hybrid” DSA process [1], we have now obtained 10 nm full pitch gratings. Recently we have studied silicon containing BCPs that incorporate a poly(2-vinylpyridine) block as a path to achieving still higher chi. For example, we have synthesized poly(4-pentamethyldisilylstyrene-block-2-vinylpyridine) (PDSS-b-P2VP) and found that this material has a chi parameter that is significantly higher than that of the BCP used for 10 nm lithography, meaning that even smaller feature sizes should be possible. Neutral top coats and cross-linked surface treatment layers were identified for PDSS-b-P2VP using the island and hole techniques that have been described previously [5]. We have succeeded in demonstrating 8 nm full pitch finger print patterns that are oriented perpendicular to the substrate. These are the smallest patterns we have managed to obtain in our system to date. 1. Blachut, G., et al. Chem. Mater (2016), 28 (24), 8951-8961. 2. Bates C. M., et al. Science (2012), 338 (6108), 775. 3. Azarnouchea, L., et al. J. Vac. Sci. Technol. B (2016) 34 (6), 061602/1-061602/10. 4. Lane A. P., et al. ACS Nano (2017), 11 (8), 7656-7665. 5. Maher, M. J., et al. Chemistry of Materials (2014), 26 (3), 1471-1479.

Proceedings Article | 19 March 2018 Presentation

A progress report on DSA of high-chi silicon containing block co-polymers (Conference Presentation)

C. Grant Willson, Natsuko Ito, Gregory Blachut, Stephen Sirard, Yasunobu Someya, Jan Doise, Ryuta Mizuochi, Austin Lane, Geert Vandenberghe, Paulina Rincon-Delgadillo, XiaoMin Yang, Christopher Ellison

Proceedings Volume 10586, 105860O (2018) https://doi.org/10.1117/12.2299966

KEYWORDS: Silicon, Reactive ion etching, Scanning transmission electron microscopy, Optical lithography, Spectroscopy, Semiconducting wafers, Chromium

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We have developed block co-polymers (BCPs) in which one of the blocks incorporates silicon and the other does not [1]. These materials provide access to BCPs with high Flory-Huggins interaction parameters (χ) and dry etch selectivity under reactive ion etching (RIE) conditions to provide Sub-20 nm patterns [2]. Recently we have investigated a hybrid chemo/grapho-epitaxy process that provides 20 nm and 10 nm full pitch patterning and we have transferred these patterns into useful substrates. This hybrid process produced 20 nm DSA with fewer defects with this material than the conventional chemo-epitaxial process. Cross-sectional scanning transmission electron microscopy (STEM) with electron energy loss spectroscopy (EELS) confirmed that the BCP features span the entire film thickness on hybrid process wafers [3]. We have now succeeded in demonstrating DSA with poly(4-methoxystyrene-block-4-trimethylsilylstyrene) (PMOST-b-PTMSS) aligned by guidelines comprised of cross linked poly(2-vinylpyridine) (Figure a). The process was demonstrated by cross-section analysis to produce features that span the entire BCP film thickness and the introduction of nitrogen into the guide line provides new evidence for the nature of the interaction between the guide lines and the BCP(Figure b). We have also reported the DSA and pattern transfer of poly(5-vinyl-1,3-benzodioxole-block-pentamethyldisilylstyrene) (PVBD-b-PDSS) at 10 nm full pitch. However, in this case, the DSA involved a trade-off between perpendicularity and dislocation defects [4]. Improved brush materials that selectively graft to an etched Cr surface rather than etched imprint resist provide oriented and aligned 5 nm line-and-space patterns that cleanly traverse the full film thickness thickness (Figure c). 1. Bates C. M., et al. Science (2012), 338 (6108), 775. 2. Azarnouchea, L., et al. J. Vac. Sci. Technol. B (2016) 34 (6), 061602/1-061602/10. 3. Blachut, G., et al. Chem. Mater (2016), 28 (24), 8951-8961. 4. Lane A. P., et al. ACS Nano (2017), 11 (8), 7656-i7665.

Proceedings Article | 21 March 2017 Paper

A method to accelerate creation of plasma etch recipes using physics and Bayesian statistics

Meghali Chopra, Rahul Verma, Austin Lane, C. Willson, Roger Bonnecaze

Proceedings Volume 10149, 101490X (2017) https://doi.org/10.1117/12.2263507

KEYWORDS: Plasma, Plasma etching, Etching, Data modeling, Calibration, Physics, Chemistry, Parallel computing, Semiconducting wafers, Sputter deposition, Diffractive optical elements, Anisotropy, Plasma systems, Process engineering, Ions

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SPIE Journal Paper | 26 July 2016

High aspect ratio patterning of photosensitive polyimide with low thermal expansion coefficient and low dielectric constant

Andrew Dick, William Bell, Brendan Luke, Erin Maines, Brennen Mueller, Brandon Rawlings, Paul Kohl, C. Grant Willson

JM3, Vol. 15, Issue 03, 033503, (July 2016) https://doi.org/10.1117/12.10.1117/1.JMM.15.3.033503

KEYWORDS: Dielectrics, Optical lithography, Polymers, Semiconducting wafers, Ultraviolet radiation, Silicon, Solids, Thin films, Sodium, Near ultraviolet

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Proceedings Article | 25 March 2016 Paper

High chi block copolymer DSA to improve pattern quality for FinFET device fabrication

HsinYu Tsai, Hiroyuki Miyazoe, Ankit Vora, Teddie Magbitang, Noel Arellano, Chi-Chun Liu, Michael Maher, William Durand, Simon Dawes, James Bucchignano, Lynne Gignac, Daniel Sanders, Eric Joseph, Matthew Colburn, C. Grant Willson, Christopher Ellison, Michael Guillorn

Proceedings Volume 9779, 977910 (2016) https://doi.org/10.1117/12.2219544

KEYWORDS: Line edge roughness, Line width roughness, Lithography, Polymers, Etching, Semiconductors, Manufacturing, Directed self assembly, Silicon, Plasma, Oxygen

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Proceedings Article | 23 March 2016 Paper

Interactions between plasma and block copolymers used in directed self-assembly patterning

Stephen Sirard, Laurent Azarnouche, Emir Gurer, William Durand, Michael Maher, Kazunori Mori, Gregory Blachut, Dustin Janes, Yusuke Asano, Yasunobu Someya, Diane Hymes, David Graves, Christopher Ellison, C. Grant Willson

Proceedings Volume 9782, 97820K (2016) https://doi.org/10.1117/12.2220305

KEYWORDS: Plasma, Polymers, Etching, Silicon, Optical lithography, Plasma etching, Tin, FT-IR spectroscopy, Directed self assembly, Reactive ion etching, Picosecond phenomena, Polymethylmethacrylate

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Proceedings Article | 20 March 2015 Paper

Directly patternable dielectric based on fluorinated polyimide

Andrew Dick, William Bell, Brendan Luke, Erin Maines, Brennan Mueller, Paul Kohl, Brandon Rawlings, C. Grant Willson

Proceedings Volume 9425, 94251D (2015) https://doi.org/10.1117/12.2085793

KEYWORDS: Dielectrics, Optical lithography, Polymers, Silicon, Semiconducting wafers, Near ultraviolet, Absorbance, Silicon films, Packaging, Ultraviolet radiation

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Proceedings Article | 20 March 2015 Paper

Aromatizing unzipping polyester for EUV photoresist

Kensuke Matsuzawa, Ryan Mesch, Mike Olah, Wade Wang, Scott Phillips, C. Grant Willson

Proceedings Volume 9425, 94251Q (2015) https://doi.org/10.1117/12.2085780

KEYWORDS: Polymers, Ultraviolet radiation, Extreme ultraviolet lithography, Absorption, Photoresist materials, Semiconducting wafers, Deep ultraviolet, Diffusion, Thin films, Bioalcohols

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SPIE Journal Paper | 16 July 2014 Open Access

Planarizing material for reverse-tone step and flash imprint lithography

Tsuyoshi Ogawa, B. Michael Jacobsson, Ryan Deschner, William Bell, Michael Lin, Yuji Hagiwara, Satoshi Takei, Makoto Hanabata, C. Grant Willson

JM3, Vol. 13, Issue 03, 031302, (July 2014) https://doi.org/10.1117/12.10.1117/1.JMM.13.3.031302

KEYWORDS: Etching, Ultraviolet radiation, Lithography, Silicon, Scanning electron microscopy, Industrial chemicals, Coating, Liquids, Plasma etching, Epoxies

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SPIE Journal Paper | 12 March 2014

Mesoscale modeling: a study of particle generation and line-edge roughness

Siddharth Chauhan, Mark Somervell, Michael Carcasi, Steven Scheer, Roger Bonnecaze, Chris Mack, C. Grant Willson

JM3, Vol. 13, Issue 01, 013012, (March 2014) https://doi.org/10.1117/12.10.1117/1.JMM.13.1.013012

KEYWORDS: Particles, Polymers, Line edge roughness, Monte Carlo methods, Diffusion, Photoresist developing, Photoresist materials, Lithography, 3D modeling, Molecules

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SPIE Journal Paper | 24 September 2013 Open Access

Reactive fluorinated surfactant for step and flash imprint lithography

Tsuyoshi Ogawa, Daniel Hellebusch, Michael Lin, B. Michael Jacobsson, William Bell, C. Grant Willson

JM3, Vol. 12, Issue 03, 031114, (September 2013) https://doi.org/10.1117/12.10.1117/1.JMM.12.3.031114

KEYWORDS: Lithography, Head-mounted displays, Glasses, Optical lithography, Microfluidics, Nanoimprint lithography, Interfaces, Natural surfaces, Chemistry, Failure analysis

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Proceedings Article | 16 April 2011 Paper

Photobase generator enabled pitch division: a progress report

Xinyu Gu, Younjin Cho, Takanori Kawakami, Yuji Hagiwara, Brandon Rawlings, Ryan Mesch, Toshiyuki Ogata, Taeho Kim, Takehiro Seshimo, Wade Wang, Arun Sundaresan, Nicholas Turro, Roel Gronheid, James Blackwell, Robert Bristol, C. Grant Willson

Proceedings Volume 7972, 79720F (2011) https://doi.org/10.1117/12.879861

KEYWORDS: Line edge roughness, Polymers, Lithography, Diffusion, Optical lithography, Photomasks, Chemical analysis, Scanning electron microscopy, Absorbance, Chemistry

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Proceedings Article | 16 April 2011 Paper

Polymer-bound photobase generators and photoacid generators for pitch division lithography

Younjin Cho, Xinyu Gu, Yuji Hagiwara, Takanori Kawakami, Toshiyuki Ogata, Brandon Rawlings, Yongjun Li, Arun Sundaresan, Nicholas Turro, Robert Bristol, James Blackwell, C. Grant Willson

Proceedings Volume 7972, 797221 (2011) https://doi.org/10.1117/12.879771

KEYWORDS: Polymers, Lithography, Line edge roughness, NOx, Analog electronics, Photomasks, Polymerization, Chlorine, Molecules, Ultraviolet radiation

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Proceedings Article | 4 April 2011 Paper

Reactive fluorinated surfactant for step and flash imprint lithography

Tsuyoshi Ogawa, Daniel Hellebusch, Michael Lin, B. Michael Jacobsson, William Bell, C. Grant Willson

Proceedings Volume 7970, 79700T (2011) https://doi.org/10.1117/12.871627

KEYWORDS: Fluorine, Silicon, Lithography, Head-mounted displays, Glasses, Optical lithography, Nanoimprint lithography, Interfaces, Information operations, Adhesives

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Proceedings Article | 3 April 2010 Paper

Planarizing material for reverse-tone step and flash imprint lithography

Tsuyoshi Ogawa, Satoshi Takei, B. Michael Jacobsson, Ryan Deschner, William Bell, Michael Lin, Yuji Hagiwara, Makoto Hanabata, C. Grant Willson

Proceedings Volume 7637, 763708 (2010) https://doi.org/10.1117/12.846430

KEYWORDS: Silicon, Ultraviolet radiation, Etching, Oxygen, Silicon carbide, Lithography, Scanning electron microscopy, Coating, Liquids, Epoxies

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Proceedings Article | 31 March 2010 Paper

Extension of 248 nm Monte Carlo, mesoscale models to 193 nm platforms

Michael Carcasi, Mark Somervell, Steven Scheer, Siddharth Chauhan, Jeffrey Strahan, C. Willson

Proceedings Volume 7639, 76392K (2010) https://doi.org/10.1117/12.846658

KEYWORDS: Systems modeling, Line edge roughness, Polymers, Diffusion, Calibration, Data modeling, Monte Carlo methods, Lithography, Molecular interactions, Stochastic processes

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Proceedings Article | 31 March 2010 Paper

Development of spin-on hard mask materials under resist in nano imprint lithography

Satoshi Takei, Tsuyoshi Ogawa, Ryan Deschner, Kane Jen, Makoto Hanabata, C. Willson

Proceedings Volume 7639, 76391C (2010) https://doi.org/10.1117/12.853200

KEYWORDS: Lithography, Photomasks, Ultraviolet radiation, Etching, Photoresist processing, Nanoimprint lithography, Electron beam lithography, Oxygen, Resistance, Silicon

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Proceedings Article | 26 March 2010 Paper

Particle generation during photoresist dissolution

Siddharth Chauhan, Mark Somervell, Michael Carcasi, Steven Scheer, Roger Bonnecaze, Chris Mack, C. Grant Willson

Proceedings Volume 7639, 763933 (2010) https://doi.org/10.1117/12.848424

KEYWORDS: Particles, Polymers, Monte Carlo methods, Photoresist materials, Photoresist developing, Lithography, Molecules, Diffusion, 3D modeling, Line edge roughness

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Proceedings Article | 26 March 2010 Paper

Photobase generator assisted pitch division

Xinyu Gu, Christopher Bates, Younjin Cho, Takanori Kawakami, Tomoki Nagai, Toshiyuki Ogata, Arunkumar Sundaresan, Nicholas Turro, Robert Bristol, Paul Zimmerman, C. Grant Willson

Proceedings Volume 7639, 763906 (2010) https://doi.org/10.1117/12.846395

KEYWORDS: Lithography, Photomasks, Critical dimension metrology, Photoresist materials, Manufacturing, Polymers, Semiconductors, Double patterning technology, Image processing, Interferometry

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SPIE Journal Paper | 1 October 2009

Fluorinated polymethacrylates as highly sensitive nonchemically amplified e-beam resists

Jeffrey Strahan, Jacob Adams, Kane Jen, Anja Vanleenhove, Colin Neikirk, Timothy Rochelle, Roel Gronheid, Carlton Willson

JM3, Vol. 8, Issue 04, 043011, (October 2009) https://doi.org/10.1117/12.10.1117/1.3274005

KEYWORDS: Polymers, Extreme ultraviolet, Polymethylmethacrylate, Electron beam lithography, Fluorine, Magnesium, Photomasks, Liquids, Chemistry, Lithography

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Proceedings Article | 1 April 2009 Paper

Polymer dissolution model: an energy adaptation of the critical ionization theory

Siddharth Chauhan, Mark Somervell, Steven Scheer, Chris Mack, Roger Bonnecaze, C. Grant Willson

Proceedings Volume 7273, 727336 (2009) https://doi.org/10.1117/12.814344

KEYWORDS: Polymers, Ionization, Monte Carlo methods, Line edge roughness, Polymer thin films, Interfaces, 3D modeling, Calibration, Molecular interactions, Motion models

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Proceedings Article | 1 April 2009 Paper

Fundamental study of optical threshold layer approach towards double exposure lithography

Xinyu Gu, Adam Berro, Younjin Cho, Kane Jen, Saul Lee, Tomoki Ngai, Toshiyuki Ogata, William Durand, Arunkumar Sundaresan, Jeffrey Lancaster, Steffen Jockusch, Paul Zimmerman, Nicholas Turro, C. Willson

Proceedings Volume 7273, 72731C (2009) https://doi.org/10.1117/12.814298

KEYWORDS: Polymers, Lithography, Crystals, Diffusion, Temperature metrology, Extreme ultraviolet lithography, Sensors, Polymer thin films, Optical lithography, Photomasks

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Proceedings Article | 1 April 2009 Paper

Development of novel UV cross-linkable materials for enhancing planarity in via applications via the correlation of simulated and experimental analyses

Satoshi Takei, Michael Lin, Sangwoong Yoon, Tomoya Ohashi, Yasuyuki Nakajima, C. Grant Willson

Proceedings Volume 7273, 72730W (2009) https://doi.org/10.1117/12.813530

KEYWORDS: Ultraviolet radiation, Coating, Lithography, Etching, Semiconducting wafers, Liquids, Chemical analysis, Antireflective coatings, Dielectrics, Industrial chemicals

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Proceedings Article | 1 April 2009 Paper

Fluorinated polymethacrylates as highly sensitive non-chemically amplified e-beam resists

Jeff Strahan, Jacob Adams, Wei-Lun Jen, Anja Vanleenhove, Colin Neikirk, Timothy Rochelle, Roel Gronheid, C. Grant Willson

Proceedings Volume 7273, 72733G (2009) https://doi.org/10.1117/12.813736

KEYWORDS: Optical proximity correction, Extreme ultraviolet, Extreme ultraviolet lithography, Data modeling, Lithography, Diagnostics, Nanoimprint lithography, Photoresist processing, Diffusion, Reticles

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Proceedings Article | 1 April 2009 Paper

Optical threshold layer and intermediate state two-photon PAG approaches to double exposure lithography

Adam Berro, Xinyu Gu, Naphtali O'Connor, Steffen Jockusch, Tomoki Nagai, Toshiyuki Ogata, Paul Zimmerman, Bryan Rice, Elizabeth Adolph, Travis Byargeon, Jose Gonzalez, Nicholas Turro, C. Grant Willson

Proceedings Volume 7273, 72731B (2009) https://doi.org/10.1117/12.814295

KEYWORDS: Polymers, Liquids, Liquid crystals, Crystals, Lithography, Molecules, Absorption, Diffusion, Nitrogen, Absorbance

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Proceedings Article | 1 April 2009 Paper

EUV resist requirements: absorbance and acid yield

Roel Gronheid, Carlos Fonseca, Michael Leeson, Jacob Adams, Jeffrey Strahan, C. Grant Willson, Bruce Smith

Proceedings Volume 7273, 727332 (2009) https://doi.org/10.1117/12.814716

KEYWORDS: Absorbance, Extreme ultraviolet, Polymethylmethacrylate, Line width roughness, Extreme ultraviolet lithography, Photons, Polymers, Quantum efficiency, Lithography, Molecules

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SPIE Journal Paper | 1 March 2009

Pattern recognition of shape-encoded hydrogel biosensor arrays

Jason Meiring, Saul Lee, Elizabeth Costner, Matthew Schmid, Timothy Michaelson, C. Grant Willson, Scott Grayson

OE, Vol. 48, Issue 03, 037201, (March 2009) https://doi.org/10.1117/12.10.1117/1.3099722

KEYWORDS: Sensors, Pattern recognition, Optical pattern recognition, Biosensors, Detection and tracking algorithms, Optical engineering, Optical alignment, Target recognition, Luminescence, Optical lithography

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SPIE Journal Paper | 1 January 2009

Materials modeling and development for use in double-exposure lithography applications

Saul Lee, Kane Jen, C. Grant Willson, Jeffrey Byers, Paul Zimmerman, Nicholas Turro

JM3, Vol. 8, Issue 01, 011011, (January 2009) https://doi.org/10.1117/12.10.1117/1.3095589

KEYWORDS: Lithography, Picture Archiving and Communication System, Photomasks, Nonlinear response, Computer simulations, Imaging systems, Photons, Electroluminescence, Photoresist developing, Absorbance

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SPIE Journal Paper | 1 July 2008

Role of surfactants in adhesion reduction for step and flash imprint lithography

Michael Lin, Daniel Hellebusch, Kai Wu, Eui Kim, Kuan-Hsun Lu, Kenneth Liechti, John Ekerdt, Paul Ho, C. Grant Willson

JM3, Vol. 7, Issue 03, 033005, (July 2008) https://doi.org/10.1117/12.10.1117/1.2968269

KEYWORDS: Polymers, Interfaces, Quartz, Adhesives, Etching, Liquids, Silicon, Lithography, Mechanics, Natural surfaces

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SPIE Journal Paper | 1 April 2008

Simulation and design of planarizing materials for reverse-tone step and flash imprint lithography

Michael Lin, Brook Chao, Jianjun Hao, Kyle Osberg, Paul Ho, C. Grant Willson

JM3, Vol. 7, Issue 02, 023008, (April 2008) https://doi.org/10.1117/12.10.1117/1.2896047

KEYWORDS: Etching, Silicon, Lithography, Capillaries, Ultraviolet radiation, Coating, Liquids, Polymers, Optical lithography, Data modeling

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Proceedings Article | 1 April 2008 Paper

An analysis of double exposure lithography options

Saul Lee, Jeffrey Byers, Kane Jen, Paul Zimmerman, Bryan Rice, Nicholas Turro, C. Grant Willson

Proceedings Volume 6924, 69242A (2008) https://doi.org/10.1117/12.773030

KEYWORDS: Lithography, Photomasks, Electroluminescence, Optical lithography, Nonlinear response, Semiconducting wafers, Double patterning technology, Imaging systems, Resolution enhancement technologies, Computer simulations

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Proceedings Article | 26 March 2008 Paper

High-index resist for 193-nm immersion lithography

Kazuya Matsumoto, Elizabeth Costner, Isao Nishimura, Mitsuru Ueda, C. Grant Willson

Proceedings Volume 6923, 692305 (2008) https://doi.org/10.1117/12.772958

KEYWORDS: Refractive index, Absorbance, Polymers, Absorption, Chlorine, Immersion lithography, Sulfur, Chemistry, Water, Imaging spectroscopy

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Proceedings Article | 26 March 2008 Paper

High resolution nanoimprint templates for dual damascene: fabrication and imprint results

Mathias Irmscher, Joerg Butschke, Ron Carpio, Brook Chao, Wei-Lun Jen, Corinna Koepernik, Lorenz Nedelmann, Jordan Owens, Frank Palmieri, Marcus Pritschow, Christian Reuter, Holger Sailer, Ken Satoodeh, Jeff Wetzel, Bruce Wilks, Grant Willson

Proceedings Volume 6921, 69210D (2008) https://doi.org/10.1117/12.772295

KEYWORDS: Etching, Chromium, Quartz, Manufacturing, Metals, Ultraviolet radiation, Photomasks, Optical lithography, Nanoimprint lithography, Lithography

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Proceedings Article | 26 March 2008 Paper

Non-chemically amplified resists for 193 nm lithography

Isao Nishimura, William Heath, Kazuya Matsumoto, Wei-Lun Jen, Saul Lee, Colin Neikirk, Tsutomu Shimokawa, Koji Ito, Koichi Fujiwara, C. Grant Willson

Proceedings Volume 6923, 69231C (2008) https://doi.org/10.1117/12.772646

KEYWORDS: Polymers, Diffusion, Line width roughness, Lithography, Optical lithography, Ultraviolet radiation, Semiconducting wafers, Chemically amplified resists, Polymer thin films, Polymethylmethacrylate

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Proceedings Article | 26 March 2008 Paper

New high-index fluids: exploiting anomalous dispersion for immersion lithography

Elizabeth Costner, Kazuya Matsumoto, Brian Long, J. Christopher Taylor, William Wojtczak, C. Grant Willson

Proceedings Volume 6923, 69230B (2008) https://doi.org/10.1117/12.772979

KEYWORDS: Absorbance, Water, Optical properties, Immersion lithography, Refraction, Absorption, Carbon, Sodium, Refractive index, Electrons

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Proceedings Article | 20 March 2008 Paper

Dual damascene BEOL processing using multilevel step and flash imprint lithography

Brook Chao, Frank Palmieri, Wei-Lun Jen, D. Hale McMichael, C. Grant Willson, Jordan Owens, Rich Berger, Ken Sotoodeh, Bruce Wilks, Joseph Pham, Ronald Carpio, Ed LaBelle, Jeff Wetzel

Proceedings Volume 6921, 69210C (2008) https://doi.org/10.1117/12.772908

KEYWORDS: Etching, Chemistry, Dielectrics, Back end of line, Lithography, Optical lithography, Resistance, Reactive ion etching, Critical dimension metrology, Metals

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Step and Flash Imprint Lithography (S-FIL®) in conjunction with Sacrificial Imprint Materials (SIM) shows promise as a cost effective solution to patterning sub 45nm features and is capable of simultaneously patterning two levels of interconnect structures, which provides a high throughput and low cost BEOL process. This paper describes the integration of S-FIL into an industry standard Cu/low-k dual damascene process that is being practiced in the ATDF at Sematech in Austin. The pattern transferring reactive ion etching (RIE) process is the most critical step and was extensively explored in this study. In addition to successful process development, the results provide useful insight into the optimal design of multilevel templates which must take into account the characteristics of both the imaging material and the dielectric layer. The template used in this study incorporates both the via and trench levels of an M2 (Metal 2) test vehicle that incorporates via chains with varying via dimensions, Kelvin test structures, serpentines, etc. The smallest vias on the template are 120nm vias with an aspect ratio of 2.0 and the smallest dense lines are 125nm/175nm with an aspect ratio of 2.9. Two inter-level dielectrics (ILD), Coral® and Black Diamond® were studied. No trench etch stop was incorporated in the ILD film stack. A multi-step, in-situ etching scheme was developed that achieves faithful pattern transfer from the sacrificial imprint material (SIM) into the underlying low k ILD with surprisingly wide process latitude. This multi-step scheme includes the following etch steps: a residual layer open, a via etch, a trench descum, a trench etch, and an SIM removal ash. Among these steps, the trench etch was found to be the most challenging to develop and it holds the key to producing high aspect ratio dual damascene features. An etching chemistry based on two fluorocarbon gases, CF₄ and C₄F₈, was found to be very effective in delivering the desired etch profiles with optimal sidewall angle, minimal facet formation. The optimized etch process can be exploited to provide substantial size reduction and/or increased aspect ratio relative to the template. In this way structures with final critical dimensions of 95nm in vias with aspect ratio of 3.0 and 67nm/233nm in dense lines with aspect ratio of 3.6 were demonstrated with wide process latitude. This enables manufacturing of the template at larger dimensions, which simplifies both fabrication and inspection. The successful development of the dual damascene RIE process at the second metal (M2) level was demonstrated in a mixed and matched build with an ATDF standard first layer metal (M1) process. The M1 dielectric was TEOS and was patterned by 248nm lithography. The M2 and Via levels used Coral as ILD and both levels were patterned simultaneously by S-FIL using Molecular Imprint Imprio 55 and Imprio 100 imprint tools. This electrical test vehicle provided solid evidence that S-FIL is fully compatible with industry standard dual damascene process.

Proceedings Article | 20 March 2008 Paper

Interfacial adhesion studies for step and flash imprint lithography

Michael Lin, Daniel Hellebusch, Kai Wu, Eui Kyoon Kim, Kuan Lu, Li Tao, Kenneth Liechti, John Ekerdt, Paul Ho, Walter Hu, C. Grant Willson

Proceedings Volume 6921, 69210E (2008) https://doi.org/10.1117/12.772797

KEYWORDS: Polymers, Quartz, Interfaces, Etching, Mechanics, Lithography, Liquids, Adhesives, Silicon, Polymer thin films

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Proceedings Article | 21 March 2007 Paper

Multilevel step and flash imprint lithography for direct patterning of dielectrics

Wei-Lun Jen, Frank Palmieri, Brook Chao, Michael Lin, Jianjun Hao, Jordan Owens, Ken Sotoodeh, Robin Cheung, C. Grant Willson

Proceedings Volume 6517, 65170K (2007) https://doi.org/10.1117/12.711602

KEYWORDS: Etching, Silicon, Lithography, Optical lithography, Back end of line, Diamond, Dielectrics, Copper, Scanning electron microscopy, Liquids

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Proceedings Article | 21 March 2007 Paper

Photocurable silicon-based materials for imprinting lithography

Jianjun Hao, Michael Lin, Frank Palmieri, Yukio Nishimura, Huang-Lin Chao, Michael Stewart, Austin Collins, Kane Jen, C. Grant Willson

Proceedings Volume 6517, 651729 (2007) https://doi.org/10.1117/12.712261

KEYWORDS: Silicon, Dielectrics, Molecules, Lithography, Annealing, Bromine, Front end of line, Back end of line, Chlorine, Optical lithography

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SPIE Journal Paper | 1 April 2006

Line edge roughness and intrinsic bias for two methacrylate polymer resist systems

Adam Pawloski, Alden Acheta, Harry Levinson, Timothy Michaelson, Andrew Jamieson, Yukio Nishimura, Carlton Willson

JM3, Vol. 5, Issue 02, 023001, (April 2006) https://doi.org/10.1117/12.10.1117/1.2200675

KEYWORDS: Line edge roughness, Polymers, Diffusion, Data modeling, Optical lithography, Image quality, Systems modeling, Photoresist materials, Chemical analysis, Scanning electron microscopy

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Proceedings Article | 29 March 2006 Paper

New high-index fluids for immersion lithography

Elizabeth Costner, J. Christopher Taylor, Stefan Caporale, William Wojtczak, Dean Dewulf, Will Conley, C. Grant Willson

Proceedings Volume 6153, 61530B (2006) https://doi.org/10.1117/12.656637

KEYWORDS: Absorbance, Water, Refraction, Digital micromirror devices, Immersion lithography, Metals, Interfaces, Reflection, Refractive index, Optical properties

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Proceedings Article | 27 March 2006 Paper

Planarization for Reverse-Tone Step and Flash Imprint Lithography

Michael Lin, Huang-Lin Chao, Jianjun Hao, Eui Kim, Frank Palmieri, Woon Kim, Michael Dickey, Paul Ho, C. Willson

Proceedings Volume 6151, 61512G (2006) https://doi.org/10.1117/12.655626

KEYWORDS: Etching, Silicon, Lithography, Capillaries, Thin films, Silicon films, Safety, Interferometry, Semiconducting wafers, Photomasks

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Proceedings Article | 24 March 2006 Paper

Photocurable Pillar Arrays Formed via AC- and Ultrasound-Induced Electrohydrodynamic Instabilities

Pavlos Tsiartas, Michael Dickey, Keris Allrich, C. Willson

Proceedings Volume 6151, 61513G (2006) https://doi.org/10.1117/12.657442

KEYWORDS: Electrodes, Polymers, Ultrasonics, Transducers, Polymer thin films, Capacitors, Photomicroscopy, Optical lithography, Glasses, Image analysis

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Proceedings Article | 23 March 2006 Paper

Multi-level step and flash imprint lithography for direct patterning of dielectrics

Frank Palmieri, Michael Stewart, Jeff Wetzel, Jianjun Hao, Yukio Nishimura, Kane Jen, Colm Flannery, Bin Li, Huang-Lin Chao, Soo Young, Woon Kim, Paul Ho, C. Willson

Proceedings Volume 6151, 61510J (2006) https://doi.org/10.1117/12.655604

KEYWORDS: Dielectrics, Copper, Sol-gels, Polymers, Silicon, Optical lithography, Chemical mechanical planarization, Liquids, Polymerization, Lithography

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Proceedings Article | 21 March 2006 Paper

Drag-a-drop: a characterization tool for immersion lithography

Derek Bassett, J. Chris Taylor, Will Conley, C. Grant Willson, Roger Bonnecaze

Proceedings Volume 6154, 61544P (2006) https://doi.org/10.1117/12.656482

KEYWORDS: Semiconducting wafers, Microfluidics, Photomasks, Polymers, Glasses, Immersion lithography, Photoresist materials, Dewetting, Reflection, Scanners

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Proceedings Article | 8 November 2005 Paper

Design and fabrication of highly complex topographic nano-imprint template for dual Damascene full 3-D imprinting

Susan MacDonald, Greg Hughes, Michael Stewart, Frank Palmieri, C. Grant Willson

Proceedings Volume 5992, 59922F (2005) https://doi.org/10.1117/12.632312

KEYWORDS: Metals, Etching, Quartz, Copper, Photomasks, Optical lithography, Manufacturing, Lithography, Semiconducting wafers, Dielectrics

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Proceedings Article | 6 May 2005 Paper

Direct imprinting of dielectric materials for dual damascene processing

Michael Stewart, Jeffery Wetzel, Gerard Schmid, Frank Palmieri, Ecron Thompson, Eui Kyoon Kim, David Wang, Ken Sotodeh, Kane Jen, Stephen Johnson, Jianjun Hao, Michael Dickey, Yukio Nishimura, Richard Laine, Douglas Resnick, C. Willson

Proceedings Volume 5751, (2005) https://doi.org/10.1117/12.599977

KEYWORDS: Dielectrics, Silicon, Copper, Semiconducting wafers, Optical lithography, Etching, Lithography, Metals, Nanoimprint lithography, Plasma etching

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Proceedings Article | 4 May 2005 Paper

The effects of chemical gradients and photoresist composition on lithographically generated line edge roughness

Timothy Michaelson, Adam Pawloski, Alden Acheta, Yukio Nishimura, C. Grant Willson

Proceedings Volume 5753, (2005) https://doi.org/10.1117/12.599848

KEYWORDS: Line edge roughness, Photoresist materials, Polymers, Diffusion, Data modeling, Semiconducting wafers, Scanning electron microscopy, Image processing, Data conversion, Mathematical modeling

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Proceedings Article | 4 May 2005 Paper

Understanding the photoresist surface-liquid interface for ArF immersion lithography

Will Conley, Robert LeSuer, Frank Fan, Allen Bard, Chris Taylor, Pavlos Tsiartas, Grant Willson, Andrew Romano, Ralph Dammel

Proceedings Volume 5753, (2005) https://doi.org/10.1117/12.601482

KEYWORDS: Photoresist materials, Semiconducting wafers, Scintillation, Liquids, Water, Immersion lithography, Polymers, Interfaces, Signal detection, Fluorine

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Proceedings Article | 4 May 2005 Paper

Fluids and resists for hyper NA immersion lithography

J. Christopher Taylor, Ramzy Shayib, Sumarlin Goh, Charles Chambers, Will Conley, Shang-Ho Lin, C. Grant Willson

Proceedings Volume 5753, (2005) https://doi.org/10.1117/12.600771

KEYWORDS: Water, Refraction, Polymers, Sodium, Immersion lithography, Photoresist materials, Microfluidics, Chlorine, Refractive index, Systems modeling

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Proceedings Article | 4 May 2005 Paper

Using mesoscale simulation to explore photoresist line edge roughness

Jason Meiring, Timothy Michaelson, Andrew Jamieson, Gerard Schmid, Carlton Willson

Proceedings Volume 5753, (2005) https://doi.org/10.1117/12.599736

KEYWORDS: Line edge roughness, Monte Carlo methods, Molecules, Polymers, Photoresist materials, Image quality, Stochastic processes, Computer simulations, Lithography, Diffusion

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SPIE Journal Paper | 1 January 2005

Nanofabrication with step and flash imprint lithography

Michael Stewart, Stephen Johnson, Sidlgata Sreenivasan, Douglas Resnick, Carlton Willson

JM3, Vol. 4, Issue 01, 011002, (January 2005) https://doi.org/10.1117/12.10.1117/1.1862650

KEYWORDS: Lithography, Optical alignment, Photomasks, Nanoimprint lithography, Nanofabrication, Printing, Optical lithography, Etching, Overlay metrology, Polymers

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SPIE Journal Paper | 1 July 2004

Low-voltage electron beam lithography resist processes: top surface imaging and hydrogen silisesquioxane bilayer

Andrew Jamieson, C. Willson, Yautzong Hsu, Alan Brodie

JM3, Vol. 3, Issue 03, (July 2004) https://doi.org/10.1117/12.10.1117/1.1758268

KEYWORDS: Line edge roughness, Electron beam lithography, Electron beams, Photoresist processing, Image processing, Imaging systems, Hydrogen, Etching, Polymers, Photomasks

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Proceedings Article | 20 May 2004 Paper

Development of imprint materials for the Step and Flash Imprint Lithography process

Frank Xu, Nicholas Stacey, Mike Watts, Van Truskett, Ian McMackin, Jin Choi, Philip Schumaker, Ecron Thompson, Daniel Babbs, S. Sreenivasan, C. Grant Willson, Norman Schumaker

Proceedings Volume 5374, (2004) https://doi.org/10.1117/12.538734

KEYWORDS: Lithography, Ultraviolet radiation, Silicon, Optical lithography, Liquids, Semiconducting wafers, Etching, Optical alignment, Scanning electron microscopy, Interfaces

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Proceedings Article | 20 May 2004 Paper

Mesoscale modeling for SFIL simulating polymerization kinetics and densification

Ryan Burns, Stephen Johnson, Gerard Schmid, Eui Kim, Michael Dickey, Jason Meiring, Sean Burns, Nicholas Stacey, C. Grant Willson, Diana Convey, Yi Wei, Peter Fejes, Kathleen Gehoski, David Mancini, Kevin Nordquist, William Dauksher, Douglas Resnick

Proceedings Volume 5374, (2004) https://doi.org/10.1117/12.536216

KEYWORDS: Etching, Polymerization, Molecules, Monte Carlo methods, Finite element methods, Lithography, Ultraviolet radiation, Molecular interactions, Scanning electron microscopy, Optical lithography

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Proceedings Article | 14 May 2004 Paper

Implications of immersion lithography on 193-nm photoresists

J. Christopher Taylor, Charles Chambers, Ryan Deschner, Robert LeSuer, Willard Conley, Sean Burns, C. Willson

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.535875

KEYWORDS: Water, Photoresist materials, Polymers, Semiconducting wafers, Scintillation, Immersion lithography, Liquids, Refraction, Silicon, Spectroscopic ellipsometry

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Proceedings Article | 14 May 2004 Paper

Understanding the role of base quenchers in photoresists

Timothy Michaelson, Andrew Jamieson, Adam Pawloski, Jeffrey Byers, Alden Acheta, C. Willson

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.537658

KEYWORDS: Photoresist materials, Line edge roughness, Critical dimension metrology, Optical lithography, Polymers, Mathematical modeling

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Proceedings Article | 14 May 2004 Paper

Resolution limitations in chemically amplified photoresist systems

Gerard Schmid, Michael Stewart, Chia-Ying Wang, Bryan Vogt, Vivek Prabhu, Eric Lin, C. Willson

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.536656

KEYWORDS: Diffusion, Photoresist materials, Polymers, Molecules, Scattering, Interfaces, Lithography, Distance measurement, Manufacturing, Chemically amplified resists

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Proceedings Article | 14 May 2004 Paper

Using scanning electrochemical microscopy to probe chemistry at the solid-liquid interface in chemically amplified immersion lithography

Robert LeSuer, Fu-Ren Fan, Allen Bard, J. Christopher Taylor, Pavlos Tsiartas, Grant Willson, Willard Conley, Gene Feit, Roderick Kunz

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.537527

KEYWORDS: Electrodes, Chemistry, Interfaces, Mercury, Immersion lithography, Platinum, Microscopy, Scanning probe microscopy, Water, Antimony

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Proceedings Article | 14 May 2004 Paper

Design of dissolution inhibitors for chemically amplified photolithographic systems

Charles Chambers, Shiro Kusumoto, Brian Osborn, Alok Vasudev, Michitaka Ootani, Leonidas Walthal, Hale McMichael, Paul Zimmerman, Willard Conley, C. Grant Willson

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.535941

KEYWORDS: Polymers, Distributed interactive simulations, Absorbance, Photoresist materials, Scanning electron microscopy, Semiconducting wafers, Picture Archiving and Communication System, Glasses, Transparency, Optical lithography

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Proceedings Article | 16 June 2003 Paper

Cationic graft polymerization lithography

Heather Johnson, Sahban Ozair, Andrew Jamieson, Brian Trinque, Colin Brodsky, C. Grant Willson

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.484974

KEYWORDS: Polymers, Lithography, Polymerization, Etching, Silicon, Crystals, Polymer thin films, Quartz, Imaging systems, Oxygen

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Proceedings Article | 16 June 2003 Paper

Employing Step and Flash imprint lithography for gate-level patterning of a MOSFET device

Britain Smith, Nicholas Stacey, J. Donnelly, David Onsongo, Todd Bailey, Chris Mackay, Douglas Resnick, William Dauksher, David Mancini, Kevin Nordquist, S. Sreenivasan, Sanjay Banerjee, John Ekerdt, Grant Willson

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.490142

KEYWORDS: Etching, Lithography, Field effect transistors, Optical alignment, Semiconducting wafers, Optical lithography, Photomasks, Oxides, Reactive ion etching, Halogens

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Proceedings Article | 16 June 2003 Open Access

Imprint lithography: lab curiosity or the real NGL

Douglas Resnick, William Dauksher, David Mancini, Kevin Nordquist, Todd Bailey, Stephen Johnson, Nicholas Stacey, John Ekerdt, C. Grant Willson, S. Sreenivasan, Norman Schumaker

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.490126

KEYWORDS: Etching, Lithography, Semiconducting wafers, Silicon, Nanoimprint lithography, Chromium, Optical alignment, Image processing, Oxides, Inspection

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Proceedings Article | 12 June 2003 Paper

Advances in TFE-based fluoropolymers for 157-nm lithography: a progress report

Iqbal Sharif, Darryl DesMarteau, Larry Ford, Gregory Shafer, Brian Thomas, Will Conley, Paul Zimmerman, Daniel Miller, Guen Su Lee, Charles Chambers, Brian Trinque, Takashi Chiba, Brian Osborn, C. Grant Willson

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485192

KEYWORDS: Polymers, Absorbance, Etching, Transparency, Resistance, Lithography, Imaging systems, Chemistry, Optical lithography, Carbon monoxide

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Proceedings Article | 12 June 2003 Paper

Deprotection volume characteristics and line-edge morphology in chemically amplified resists

Ronald Jones, Tengjiao Hu, Vivek Prabhu, Christopher Soles, Eric Lin, Wen-li Wu, Dario Goldfarb, Marie Angelopoulos, Brian Trinque, C. Grant Willson

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485146

KEYWORDS: Line edge roughness, Polymers, Scattering, Diffusion, Fractal analysis, Chemically amplified resists, Fuzzy logic, Photoresist materials, Molecules, Motion models

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Proceedings Article | 12 June 2003 Paper

Fundamental study of photoresist dissolution with real-time spectroscopic ellipsometry and interferometry

Sean Burns, Gerard Schmid, Brian Trinque, James Willson, Jennifer Wunderlich, Pavlos Tsiartas, James Taylor, Ryan Burns, C. Wilson

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485182

KEYWORDS: Polymers, Interferometry, Data modeling, Photoresist materials, Water, Ellipsometry, Spectroscopic ellipsometry, Reflectivity, Refraction, Thin films

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Proceedings Article | 12 June 2003 Paper

Dissolution inhibitors for 157-nm photolithography

Charles Chambers, Shiro Kusumoto, Guen Su Lee, Alok Vasudev, Leonidas Walthal, Brian Osborn, Paul Zimmerman, Will Conley, C. Grant Willson

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485191

KEYWORDS: Polymers, Distributed interactive simulations, Semiconducting wafers, Photoresist materials, Carbon monoxide, Carbonates, Optical lithography, Lithography, Absorbance, Fluorine

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Proceedings Article | 12 June 2003 Paper

Negative photoresist for 157-nm microlithography: a progress report

Will Conley, Brian Trinque, Daniel Miller, Stefan Caporale, Brian Osborn, Shiro Kumamoto, Matthew Pinnow, Ryan Callahan, Charles Chambers, Guen Su Lee, Paul Zimmerman, C. Grant Willson

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485194

KEYWORDS: Polymers, Photoresist materials, Transparency, Imaging systems, Spectroscopy, Photomasks, Carbon monoxide, Optical lithography, Binary data, Absorbance

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Proceedings Article | 12 June 2003 Paper

Diffusion-induced line-edge roughness

Michael Stewart, Gerard Schmid, Dario Goldfarb, Marie Angelopoulos, C. Grant Willson

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.483734

KEYWORDS: Diffusion, Surface roughness, Line edge roughness, Polymers, Atomic force microscopy, Monte Carlo methods, Lithography, Photoresist materials, Molecules, Photomasks

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SPIE Journal Paper | 1 October 2002

High resolution templates for step and flash imprint lithography

Douglas Resnick, William Dauksher, David Mancini, Kevin Nordquist, Eric Ainley, Kathleen Gehoski, Jeff Baker, Todd Bailey, B. Choi, Stephen Johnson, S. Sreenivasan, John Ekerdt, C. Grant Willson

JM3, Vol. 1, Issue 03, (October 2002) https://doi.org/10.1117/12.10.1117/1.1508410

KEYWORDS: Lithography, Scanning electron microscopy, Glasses, Printing, Overlay metrology, Distortion, Chromium, Photomasks, Solids, Defect inspection

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Proceedings Article | 24 July 2002 Paper

Effect of humidity on deprotection kinetics in chemically amplified resists

Sean Burns, David Medeiros, Heather Johnson, Gregory Wallraff, William Hinsberg, C. Grant Willson

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474230

KEYWORDS: Humidity, Photoresist materials, Nitrogen, FT-IR spectroscopy, Semiconducting wafers, Chemically amplified resists, Environmental monitoring, Polymers, Switching, Spectroscopy

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Proceedings Article | 24 July 2002 Paper

Dissolution inhibitors for 157-nm microlithography

Will Conley, Daniel Miller, Charles Chambers, Brian Osborn, Raymond Hung, Hoang Tran, Brian Trinque, Matthew Pinnow, Takashi Chiba, Scott McDonald, Paul Zimmerman, Ralph Dammel, Andrew Romano, C. Grant Willson

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474282

KEYWORDS: Polymers, Absorbance, Photoresist materials, Imaging systems, Lithography, Semiconducting wafers, Transparency, Optical lithography, Vacuum ultraviolet, Phase measurement

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Proceedings Article | 24 July 2002 Paper

Measurement of the spatial evolution of the deprotection reaction front with nanometer resolution using neutron reflectometry

Eric Lin, Christopher Soles, Dario Goldfarb, Brian Trinque, Sean Burns, Ronald Jones, Joseph Lenhart, Marie Angelopoulos, C. Grant Willson, Sushil Satija, Wen-li Wu

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474229

KEYWORDS: Polymers, Reflectivity, Interfaces, X-rays, Reflectometry, Photoresist materials, Spatial resolution, Diffusion, Data modeling, Scattering

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Proceedings Article | 24 July 2002 Paper

Acid mobility in chemically amplified photoresists

Michael Stewart, Darren Becker, Timothy Stachowiak, Gerard Schmid, Timothy Michaelson, Hoang Tran, C. Grant Willson

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474168

KEYWORDS: Diffusion, Polymers, Glasses, Photoresist materials, Molecules, Adaptive optics, Temperature metrology, Systems modeling, Chemical reactions, Chemical analysis

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In a chemically amplified resist the exposure energy is used to generate a catalytic species, which promotes a solubility-switching reaction during a post exposure processing step. Using an absorbed photon to generate a catalyst, instead of using it to directly cause a solubility-switching photochemical reaction, allows for much lower exposure doses to be used for patterning since the catalytic species can eventually promote multiple solubility-switching events instead of just one. Some level of catalyst mobility is necessary to achieve the amplification effect as the catalyst must move from reaction site to reaction site, but any catalyst mobility creates the possibility of movement from exposed regions into unexposed regions causing image blur or line width spreading. As the catalyst diffuses in the resist, it promotes chemical reactions; these chemical reactions complicate analyses of catalyst diffusion by changing the chemical environment of the diffusant. Thus, the material properties of the surrounding resin are changing, sometimes drastically, as the catalyst diffuses. In addition to simple changes in material type, the chemical reaction also generates a transient material state as reaction by-products either remain in the resist film or desorb. The variation in lifetime of this transient state is another factor that must be considered in a full analysis. This work reports a method to separate reaction effects from catalyst diffusion effects. Acid diffusion in polymers which are close structural analogues to poly(4-t-butyloxycarbonyloxystrene) (TBOCST), while being unreactive to diffusing acidic molecules, was studied. Specifically, the diffusion properties of photogenerated perfluorobutanesulfonic acid in the unreactive TBOCST analogues poly(4-isopropyloxycarbonyloxystyrene) and poly(4-neopentyloxycarbonyloxysytrene) are reported. Measuring and understanding diffusion in these analogue polymers provides insight into the more complicated, and more important, reaction-diffusion processes of TBOCST.

Proceedings Article | 24 July 2002 Paper

Advances in resists for 157-nm microlithography

Brian Trinque, Brian Osborn, Charles Chambers, Yu-Tsai Hsieh, Schuyler Corry, Takashi Chiba, Raymond Hung, Hoang Tran, Paul Zimmerman, Daniel Miller, Will Conley, C. Grant Willson

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474272

KEYWORDS: Polymers, Absorbance, Transparency, Fluorine, Vacuum ultraviolet, Spectroscopy, Phase shifts, Optical lithography, Carbon monoxide, Silica

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Proceedings Article | 24 July 2002 Paper

Mesoscale simulation of positive tone chemically amplified photoresists

Gerard Schmid, Sean Burns, Michael Stewart, C. Grant Willson

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474237

KEYWORDS: Monte Carlo methods, Polymers, Photoresist materials, Ions, Computer simulations, Molecules, Lithography, Line edge roughness, Chemically amplified resists, Polymer thin films

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Proceedings Article | 24 July 2002 Paper

New methods for fabricating step and flash imprint lithography templates

Douglas Resnick, Todd Bailey, David Mancini, Kevin Nordquist, William Dauksher, Eric Ainley, A. Talin, Kathleen Gehoski, Jeff Baker, Byung Choi, Stephen Johnson, Matthew Colburn, Mario Meissl, S. Sreenivasan, John Ekerdt, C. Grant Willson

Proceedings Volume 4608, (2002) https://doi.org/10.1117/12.437269

KEYWORDS: Etching, Chromium, Oxides, Semiconducting wafers, Quartz, Glasses, Scanning electron microscopy, Lithography, Printing, Photomasks

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Proceedings Article | 24 July 2002 Paper

Hydrogen silsesquioxane bilayer resist process for low-voltage electron beam lithography

Andrew Jamieson, C. Grant Willson, Yautzong Hsu, Alan Brodie

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474194

KEYWORDS: Etching, Electron beams, Monte Carlo methods, Photoresist processing, Hydrogen, Imaging systems, Electron beam lithography, Photomasks, Oxygen, Reactive ion etching

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Proceedings Article | 24 July 2002 Paper

Negative photoresist for 157-nm microlithography; a progress report

Will Conley, Brian Trinque, Daniel Miller, Paul Zimmerman, Takanori Kudo, Ralph Dammel, Andrew Romano, C. Grant Willson

Proceedings Volume 4690, (2002) https://doi.org/10.1117/12.474187

KEYWORDS: Photoresist materials, Polymers, Absorbance, Semiconducting wafers, Spectroscopy, Transparency, Photomasks, Silicon, FT-IR spectroscopy, Optical lithography

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Proceedings Article | 24 July 2002 Paper

Low-cost nanostructure patterning using step and flash imprint lithography

S. Sreenivasan, C. Grant Willson, Norman Schumaker, Douglas Resnick

Proceedings Volume 4608, (2002) https://doi.org/10.1117/12.437804

KEYWORDS: Lithography, Extreme ultraviolet, Optical lithography, Photomasks, Inspection, Semiconducting wafers, Extreme ultraviolet lithography, Nanostructures, Microelectronics, Manufacturing

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Proceedings Article | 1 July 2002 Paper

High-resolution templates for step and flash imprint lithography

Douglas Resnick, William Dauksher, David Mancini, Kevin Nordquist, Eric Ainley, Kathleen Gehoski, Jeff Baker, Todd Bailey, Byung Choi, Stephen Johnson, S. Sreenivasan, John Ekerdt, C. Grant Willson

Proceedings Volume 4688, (2002) https://doi.org/10.1117/12.472293

KEYWORDS: Etching, Quartz, Chromium, Scanning electron microscopy, Photomasks, Semiconducting wafers, Glasses, Lithography, Printing, Oxides

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Proceedings Article | 1 July 2002 Paper

Cost of ownership analysis for patterning using step and flash imprint lithography

S. Sreenivasan, C. Grant Willson, Norman Schumaker, Douglas Resnick

Proceedings Volume 4688, (2002) https://doi.org/10.1117/12.472275

KEYWORDS: Lithography, Extreme ultraviolet, Optical lithography, Photomasks, Inspection, Semiconducting wafers, Microelectronics, Extreme ultraviolet lithography, Manufacturing, Etching

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Proceedings Article | 24 August 2001 Paper

Resist materials for 157-nm microlithography: an update

Raymond Hung, Hoang Tran, Brian Trinque, Takashi Chiba, Shintaro Yamada, Daniel Sanders, Eric Connor, Robert Grubbs, John Klopp, Jean Frechet, Brian Thomas, Gregory Shafer, Darryl DesMarteau, Will Conley, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436870

KEYWORDS: Polymers, Absorbance, Fluorine, Carbon monoxide, Polymerization, Palladium, Transparency, Nickel, Lithography, Vacuum ultraviolet

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Proceedings Article | 24 August 2001 Paper

Resist rehydration during thick film processing

Octavia Lehar, Mark Spak, Stephen Meyer, Ralph Dammel, Colin Brodsky, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436878

KEYWORDS: Semiconducting wafers, Diffusion, Photoresist materials, Quartz, Humidity, Crystals, Absorption, Lithography, Thin films, Spectroscopy

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Proceedings Article | 24 August 2001 Paper

Mechanistic understanding of line-end shortening

Michael Stewart, Gerard Schmid, Sergei Postnikov, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436844

KEYWORDS: Diffusion, Polymers, Photomasks, Semiconducting wafers, Imaging systems, Photoresist materials, Diffraction, Printing, Image acquisition, Lithography

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Proceedings Article | 24 August 2001 Paper

Rational design of bleachable nonchemically amplified DUV photoactive compounds

Benjamen Rathsack, Peter Tattersall, Cyrus Tabery, Kathleen Lou, Timothy Stachowiak, David Medeiros, Jeff Albelo, Peter Pirogovsky, Dennis McKean, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436887

KEYWORDS: Picture Archiving and Communication System, Deep ultraviolet, Chromophores, Photoresist processing, Lithography, Absorbance, Molecules, Mask making, Photomasks, Hydrogen

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Proceedings Article | 24 August 2001 Paper

Dissolution behavior of fluoroalcohol-substituted polystyrenes

Daniel Hall, Brian Osborn, Kyle Patterson, Sean Burns, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436831

KEYWORDS: Polymers, Absorbance, Photoresist materials, Semiconducting wafers, Head-mounted displays, Coating, Liquids, Analog electronics, Magnesium, Nitrogen

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Proceedings Article | 24 August 2001 Paper

Top surface imaging at 157-nm

Andrew Jamieson, Mark Somervell, Hoang Tran, Raymond Hung, Scott MacDonald, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436872

KEYWORDS: Polymers, Etching, Absorbance, Line edge roughness, Opacity, Polymerization, Binary data, Silicon, Photomasks, Transparency

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Proceedings Article | 24 August 2001 Paper

Understanding molecular-level effects during post-exposure processing

Gerard Schmid, Mark Smith, Chris Mack, Vivek Singh, Sean Burns, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436829

KEYWORDS: Polymers, Photoresist materials, Molecules, Photoresist developing, Lithography, Computer simulations, Polymer thin films, 3D modeling, Scanning electron microscopy, Mathematical modeling

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Proceedings Article | 24 August 2001 Paper

Understanding nonlinear dissolution rates in photoresists

Sean Burns, Allen Gardiner, Val Krukonis, Paula Wetmore, Jodie Lutkenhaus, Gerard Schmid, Lewis Flanagin, C. Grant Willson

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436876

KEYWORDS: Polymers, Oxygen, Surface roughness, Picture Archiving and Communication System, Medium wave, Polymer thin films, Photoresist materials, Ionization, FT-IR spectroscopy, Oxidation

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Proceedings Article | 20 August 2001 Paper

Advances in graft polymerization lithography

Colin Brodsky, Brian Trinque, Heather Johnson, C. Grant Willson

Proceedings Volume 4343, (2001) https://doi.org/10.1117/12.436660

KEYWORDS: Polymers, Polymerization, Silicon, Oxides, Lithography, Deposition processes, Liquids, Chemistry, Photoresist processing, Image processing

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Proceedings Article | 20 August 2001 Paper

Layer-to-layer alignment for step and flash imprint lithography

Byung Choi, Mario Meissl, Matthew Colburn, Todd Bailey, Paul Ruchhoeft, S. Sreenivasan, F. Prins, Sanjay Banerjee, John Ekerdt, C. Grant Willson

Proceedings Volume 4343, (2001) https://doi.org/10.1117/12.436662

KEYWORDS: Optical alignment, Photomasks, Lithography, Semiconducting wafers, Overlay metrology, Liquids, Optical lithography, Ultraviolet radiation, Microscopes, Projection lithography

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Proceedings Article | 22 January 2001 Paper

Characterization of an acetal-based chemically amplified resist for 257-nm laser mask fabrication

Benjamen Rathsack, Cyrus Tabery, Jeff Albelo, Peter Buck, C. Grant Willson

Proceedings Volume 4186, (2001) https://doi.org/10.1117/12.410739

KEYWORDS: Photomasks, Chromium, Reflectivity, Oxides, Absorption, Refraction, Chemically amplified resists, Lithography, Photoresist processing, Mask making

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Proceedings Article | 21 July 2000 Paper

Step and flash imprint lithography for sub-100-nm patterning

Matthew Colburn, Annette Grot, Marie Amistoso, Byung Choi, Todd Bailey, John Ekerdt, S. Sreenivasan, James Hollenhorst, C. Grant Willson

Proceedings Volume 3997, (2000) https://doi.org/10.1117/12.390082

KEYWORDS: Etching, Lithography, Optical lithography, Reactive ion etching, Silicon, Metals, Polymethylmethacrylate, Halogens, Semiconducting wafers, Ultraviolet radiation

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Proceedings Article | 23 June 2000 Paper

Study of acid transport using IR spectroscopy and SEM

Michael Stewart, Mark Somervell, Hoang Tran, Sergei Postnikov, C. Grant Willson

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388353

KEYWORDS: Diffusion, Scanning electron microscopy, Sensors, Polymers, Infrared spectroscopy, Glasses, Photoresist materials, Information operations, Temperature metrology, Silicon

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Proceedings Article | 23 June 2000 Paper

Polymers for 157-nm photoresist applications: a progress report

Kyle Patterson, Mikio Yamachika, Raymond Hung, Colin Brodsky, Shintaro Yamada, Mark Somervell, Brian Osborn, Daniel Hall, Gordana Dukovic, Jeff Byers, Will Conley, C. Grant Willson

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388320

KEYWORDS: Photoresist materials, Polymers, Absorbance, Photoresist developing, Transparency, Deep ultraviolet, Etching, Vacuum ultraviolet, Resistance, Fluorine

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Proceedings Article | 23 June 2000 Paper

Using alicyclic polymers in top surface imaging systems to reduce line-edge roughness

Mark Somervell, David Fryer, Brian Osborn, Kyle Patterson, Sungseo Cho, Jeff Byers, C. Grant Willson

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388311

KEYWORDS: Polymers, Line edge roughness, Glasses, Semiconducting wafers, Imaging systems, Etching, FT-IR spectroscopy, Photoresist materials, Image resolution, Absorbance

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Proceedings Article | 23 June 2000 Paper

Recent advances in a molecular level lithography simulation

Gerard Schmid, Vivek Singh, Lewis Flanagin, Michael Stewart, Sean Burns, C. Grant Willson

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388354

KEYWORDS: Polymers, Computer simulations, Molecules, Diffusion, Lithography, Monte Carlo methods, Photoresist materials, Performance modeling, Deep ultraviolet, Polymer thin films

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Proceedings Article | 23 June 2000 Paper

Simulation-based formulation of a nonchemically amplified resist for 257-nm laser mask fabrication

Benjamen Rathsack, Cyrus Tabery, Timothy Stachowiak, Jeff Albelo, C. Grant Willson

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388345

KEYWORDS: Picture Archiving and Communication System, Lithography, Quantum efficiency, Absorbance, Photomasks, Photoresist developing, Photoresist materials, Deep ultraviolet, Photoresist processing, Refraction

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The demand for smaller and more uniform features on photomasks has inspired consideration of a DUV (257 nm) resist process for optical pattern generation. Chemically amplified resists require storage and exposure in carbon filtered environments, and they require post-exposure bakes. Few mask facilities are set up to handle chemically amplified resists commonly used in deep UV wafer fabrication process. Hence, it is appropriate to explore the lithographic performance of non-chemically amplified resist materials for 257 nm laser photomask lithography. Resist characterization and lithography simulation were used to formulate a 257 nm resist from DNQ/novolak materials provided by a commercial resist supplier. Diazonaphthoquinone (DNQ)/novolak resists have not been used for DUV Integrated Circuit (IC) applications mainly due to the low sensitivity and the strong absorbance of the DNQ photoactive compound (PAC) at 248 nm. However, a 2,1,4 DNQ based resist has been characterized that bleaches at 257 nm and inhibits novolak. The photoproduct of the 2,1,4 DNQ PAC is much more transparent at 257 nm than 248 nm. Novolak resin also has an absorbance minimum in the DUV at 257 nm that provides transparency similar to poly (hydroxystyrene). Traditional photoresist formulation requires tedious, iterative, and expensive manufacturing trials. Resist characterization and lithography simulation can be used to relate lithographic performance (resolution, sidewall and process latitude) to resist formulation parameters (PAC concentration, developer concentration, etc.), thereby supporting the formulation optimization. An exposure system using a 257 nm frequency doubled argon laser system has been constructed to study the resist photokinetics. Dill exposure parameters (A, B and C) have been extracted for a 2,1,4 DNQ/novolak based resist. Dissolution rate measurements have been made with a development rate monitor developed at the University of Texas at Austin. Simulation using the exposure and development rate models were used to determine the resist formulation that maximizes the sidewall angle and exposure latitude for isolated resist spaces. Preliminary experiments reveal that a DNQ/novolak resist is capable of resolving 0.30 micrometer linewidths using a 257 nm optical pattern generator.

Proceedings Article | 23 June 2000 Paper

Design and study of aqueous processable positive-tone photoresists

Shintaro Yamada, Jordan Owens, Timo Rager, Morton Nielsen, Jeff Byers, C. Grant Willson

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388341

KEYWORDS: Polymers, Photoresist materials, Etching, Switches, Dry etching, Antimony, Standards development, Photoresist developing, Imaging systems, Silicon

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Proceedings Article | 23 June 2000 Paper

Negative-tone 193-nm resists

Sungseo Cho, Anthony Vander Heyden, Jeff Byers, C. Grant Willson

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388343

KEYWORDS: Polymers, Lithography, Nitrogen, Liquids, Switches, Optical lithography, Absorbance, Chemistry, Modulation, Industrial chemicals

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Proceedings Article | 30 December 1999 Paper

Lithography simulation of sub-0.30-um resist features for photomask fabrication using i-line optical pattern generators

Benjamen Rathsack, Cyrus Tabery, Cecilia Philbin, C. Grant Willson

Proceedings Volume 3873, (1999) https://doi.org/10.1117/12.373343

KEYWORDS: Photomasks, Reflectivity, Antireflective coatings, Reflection, Photoresist processing, Interfaces, Photoresist materials, Refraction, Coating, Chromium

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The inorganic antireflection coating (AR3-chromium oxide) commonly used on photomask blanks was designed to minimize flare in h-line (405 nm) lithography steppers. The reflection of light (flare) off this coating (air-photomask) increases with shorter exposure wavelengths. High levels of flare occur in 248 nm and 193 nm IC steppers due to reflections off of the photomask surface. The reflections (standing waves) in photomask resists also increase during exposure using lower wavelengths of light. Lithography simulations and photomask manufacturing trials have led to resist processes that can generate sub-0.30 micron resist features on photomasks with I- line optical pattern generators (ALTA 3500). Lower developer concentration, higher exposure doses and the minimization of standing waves by incorporating a post-exposure bake and/or organic antireflection coatings (ARC) maximizes resolution. High resolution photoresists show standing waves on photomasks fabricated with optical pattern generators. Low contrast resist processes show only small standing waves or in certain cases resist 'footing.' The use of organic antireflection coatings can minimize standing waves and allow the use of high contrast resist processes. ARCs reduce the swing ratio, which improves linewidth uniformity. ARCs also improve the adhesion of the resist to the photomask surface. Simulations reveal that the optimal ARC coating thickness is around 46 nm for typical I-line systems and around 50 nm for 257 nm non- chemically amplified photomask resists. Preliminary I-line photomask manufacturing trials have been done with bottom antireflection coatings at the DPI Reticle Technology Center. The first process trials reveal that the standing waves in high resolution resists were reduced but not removed. Very precise control of the ARC thickness must be exercised to completely extinguish standing waves and careful film thickness optimization appears to be necessary to minimize these reflections.

Proceedings Article | 30 December 1999 Paper

Characterization of a non-chemically amplified resist for photomask fabrication using a 257-nm optical pattern generator

Benjamen Rathsack, Cyrus Tabery, Timothy Stachowiak, Tim Dallas, Cheng-Bai Xu, Mike Pochkowski, C. Grant Willson

Proceedings Volume 3873, (1999) https://doi.org/10.1117/12.373362

KEYWORDS: Picture Archiving and Communication System, Photomasks, Absorption, Lithography, Absorbance, Transparency, Deep ultraviolet, Photoresist processing, Photoresist developing, Mask making

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I-line optical pattern generators using non-chemically amplified resists have become the workhorses for high throughput mask fabrication. The demand for smaller and more uniform features on photomasks has driven the development of a 257 nm optical pattern generator. A non-chemically amplified resist is being developed to maximize the performance of this new 257 nm mask tool. Resist characterization and lithography simulation are being used to formulate a non-chemically amplified resist for 257 nm optical pattern generators. Non- chemically amplified resists are advantageous for us in mask fabrication due to their storage and post-exposure stability. Chemically amplified resists may provide higher performance but they also require environmental mini-environments and a post-exposure bake equipment not commonly present in mask houses. Diazonaphthoquinone (DNQ)/novolak resists have not been used for DUV Integrated Circuit (IC) applications mainly due to the low sensitivity and the strong absorbance of the DNQ photoactive compound (PAC) at 248 nm. However, a 2,1,4 DNQ based resist has been characterized that bleaches at 257 nm and inhibits novolak. The photoproduct of the 2,1,4 DNQ PAC is much more transparent at 257 nm than 248 nm. Novolak resin is too strongly absorbing for use in formulating efficient 248 nm resists, but novolak has an absorbance minimum at 257 nm that provides transparency similar to poly (hydroxystyrene). Lithography simulation is being used to develop a non- chemically amplified resist to minimize the expensive iteration of manufacturing trials. An exposure system using a 257 nm frequency double Ar laser system has been constructed to study the resist photokinetics. Dill exposure parameters (A, B and C) have been extracted for a 2,1,4 DNQ/novolak based resist. Dissolution rate measurements have been made with a DRM developed at the University of Texas at Austin. Simulation is used to determine the optimal resist absorption, bleaching, dose and dissolution properties to maximize resolution. It is possible to formulate a high performance resist for 257 nm if care is taken in optimization of the formulation.

Proceedings Article | 25 June 1999 Paper

Step and flash imprint lithography: a new approach to high-resolution patterning

Matthew Colburn, Stephen Johnson, Michael Stewart, S. Damle, Todd Bailey, Bernard Choi, M. Wedlake, Timothy Michaelson, S. Sreenivasan, John Ekerdt, C. Grant Willson

Proceedings Volume 3676, (1999) https://doi.org/10.1117/12.351155

KEYWORDS: Etching, Semiconducting wafers, Lithography, Silicon, Photomasks, Quartz, Ultraviolet radiation, Liquids, Interfaces, Chromium

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Proceedings Article | 11 June 1999 Paper

Optical lithography simulation and photoresist optimization for photomask fabrication

Benjamen Rathsack, Cyrus Tabery, Steven Scheer, Mike Pochkowski, Cecilia Philbin, Franklin Kalk, Clifford Henderson, Peter Buck, C. Grant Willson

Proceedings Volume 3678, (1999) https://doi.org/10.1117/12.350173

KEYWORDS: Photomasks, Refraction, Lithography, Picture Archiving and Communication System, Data modeling, Photoresist materials, Device simulation, Chromium, Photoresist processing, Optical simulations

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Proceedings Article | 11 June 1999 Paper

Carbon-rich cyclopolymers: their synthesis, etch resistance, and application to 193-nm microlithography

Dario Pasini, Eric Low, Robert Meagley, Jean Frechet, C. Grant Willson, Jeff Byers

Proceedings Volume 3678, (1999) https://doi.org/10.1117/12.350166

KEYWORDS: Polymers, Etching, Resistance, Optical lithography, Lithography, Glasses, Signal processing, Absorbance, Photoresist materials, Chemically amplified resists

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Proceedings Article | 29 June 1998 Paper

Improving the performance of 193-nm photoresists based on alicyclic polymers

Kyle Patterson, Uzodinma Okoroanyanwu, Tsutomu Shimokawa, Sungseo Cho, Jeff Byers, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312356

KEYWORDS: Polymers, Etching, Photoresist materials, Lithography, Photomasks, Resistance, Photoresist developing, Polymerization, Bioalcohols, Absorbance

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Proceedings Article | 29 June 1998 Paper

Some aspects of thick-film resist performance and modeling

Andreas Erdmann, Clifford Henderson, C. Grant Willson, Ralph Dammel

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312349

KEYWORDS: Refractive index, Computer simulations, Photoresist processing, Photoresist materials, Optical simulations, Performance modeling, Data modeling, Scanning electron microscopy, Diffraction, Photoresist developing

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Proceedings Article | 29 June 1998 Paper

Top surface imaging through silylation

Sergei Postnikov, Mark Somervell, Clifford Henderson, Steven Katz, C. Grant Willson, Jeff Byers, Anwei Qin, Qinghuang Lin

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312370

KEYWORDS: Etching, Lithography, Diffusion, Photoresist materials, Image processing, Semiconducting wafers, Photoresist processing, Oxygen, Absorbance, Silicon

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Proceedings Article | 29 June 1998 Paper

Probabilistic model for the mechanism of phenolic polymer dissolution

Lewis Flanagin, Christopher McAdams, Pavlos Tsiartas, Clifford Henderson, William Hinsberg, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312416

KEYWORDS: Polymers, Polymerization, Ionization, Photoresist materials, Data modeling, Diffusion, Polymer thin films, Photoresist developing, Etching, Polymethylmethacrylate

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Proceedings Article | 29 June 1998 Paper

Design and study of water-soluble positive- and negative-tone imaging materials

Jennifer Havard, Dario Pasini, Jean Frechet, David Medeiros, Kyle Patterson, Shintaro Yamada, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312351

KEYWORDS: Polymers, Carbonates, Chemistry, Molecules, Switches, Polymer thin films, Spectroscopy, Nitrogen, Chemical species, Standards development

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Proceedings Article | 29 June 1998 Paper

Positive- and negative-tone water-processable photoresists: a progress report

Shintaro Yamada, David Medeiros, Kyle Patterson, Wei-Lun Jen, Timo Rager, Qinghuang Lin, Carlos Lenci, Jeff Byers, Jennifer Havard, Dario Pasini, Jean Frechet, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312414

KEYWORDS: Polymers, Photoresist materials, Switches, Photoresist developing, Etching, Imaging systems, Resistance, Photoresist processing, Polymer thin films, Chromophores

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Proceedings Article | 29 June 1998 Paper

Monitoring photoacid generation in chemically amplified resist systems

Uzodinma Okoroanyanwu, Jeff Byers, Ti Cao, Stephen Webber, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312357

KEYWORDS: Luminescence, Polymers, Photoresist materials, Polymer thin films, Chemically amplified resists, Quantum efficiency, Semiconducting wafers, Deep ultraviolet, Lithography, Data modeling

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Proceedings Article | 29 June 1998 Paper

Modeling parameter extraction for DNQ-novolak thick film resists

Clifford Henderson, Steven Scheer, Pavlos Tsiartas, Benjamen Rathsack, John Sagan, Ralph Dammel, Andreas Erdmann, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312415

KEYWORDS: Refractive index, Data modeling, Photoresist developing, Photoresist materials, Reflectivity, Software development, Silicon, Lithography, Absorbance, Picture Archiving and Communication System

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Proceedings Article | 29 June 1998 Paper

Improved simulation of photoresists using new development models

Ralph Dammel, John Sagan, Elaine Kokinda, Neville Eilbeck, Chris Mack, Graham Arthur, Clifford Henderson, Steven Scheer, Benjamen Rathsack, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312399

KEYWORDS: Photoresist developing, Data modeling, Photoresist materials, Radon, Autoregressive models, Diffusion, Affine motion model, Standards development, Chlorine, Picture Archiving and Communication System

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Proceedings Article | 29 June 1998 Paper

Sensitivity and image quality of resists with electron-beam, ion-beam, and optical exposure

Nicholas Rau, Andrew Neureuther, Taro Ogawa, Randall Kubena, Fred Stratton, Charles Fields, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312465

KEYWORDS: Ion beams, Diffusion, Lithography, Scanning electron microscopy, Image quality, Optical lithography, Deep ultraviolet, Photoresist materials, Ions, Photoresist developing

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Proceedings Article | 29 June 1998 Paper

Dissolution of phenolic polymers in aqueous base: the influence of polymer structure

Christopher McAdams, Lewis Flanagin, Clifford Henderson, Adam Pawlowski, Pavlos Tsiartas, C. Grant Willson

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312345

KEYWORDS: Polymers, Ionization, Hydrogen, Photoresist materials, Diffusion, Deep ultraviolet, Chromophores, Photoresist developing, Polarization, Ions

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Proceedings Article | 7 July 1997 Paper

Bleaching-induced changes in the dispersion curves of DNQ photoresists

Clifford Henderson, C. Grant Willson, Ralph Dammel, Ron Synowicki

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275861

KEYWORDS: Refractive index, Photoresist materials, Lithography, Absorption, Absorbance, Ultraviolet radiation, Data modeling, Semiconducting wafers, Dielectrics, Spectroscopic ellipsometry

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Proceedings Article | 7 July 1997 Paper

Acid diffusion through polymer films

Ping Zhang, Andrew Eckert, C. Grant Willson, Stephen Webber, Jeff Byers

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275903

KEYWORDS: Diffusion, Polymer thin films, Polymers, Luminescence, Sensors, Quartz, Photoresist materials, Critical dimension metrology, In situ metrology, Data analysis

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In order to perform 0.2 micrometer processes, one needs to study the diffusion of photoacid generators within the photoresist system, since diffusion during post exposure bake time has an influence on the critical dimension (CD). We have developed a new method to study the diffusion of photoacid generators within a polymer film. This new method is based on monitoring the change of the fluorescence intensity of a pH- sensitive fluorescent dye caused by the reaction with photoacid. A simplified version of this experiment has been conducted by introducing acid vapor to quench the fluorescence intensity of this pH sensor. A thin polymer film is spin cast onto the sensor to create a barrier to the acid diffusion process. During the acid diffusion process, the fluorescence intensity of this pH sensor is measured in situ, using excitation and emission wavelengths at 466 nm and 516 nm, respectively. Fluoresceinamine, the pH sensitive fluorescent dye, is covalently bonded onto the treated quartz substrate to form a single dye layer. Poly(hydroxystyrene) (M_n equals 13k, T_g equals 180 degrees Celsius) in PGMEA (5% - 18% by weight) is spin cast onto this quartz substrate to form films with varying thickness. The soft bake time is 60 seconds at 90 degrees Celsius and a typical film has a thickness of 1.4 micrometers. Trifluoroacetic acid is introduced into a small chamber while the fluorescence from this quartz window is observed. Our study focuses on finding the diffusion constant of the vaporized acid (trifluoroacetic acid) in the poly(hydroxystyrene) polymer film. By applying the Fick's second law, (I_t - I_o)/(I_(infinity ) - I_o) equals erfc [L/(Dt)^1/2] is obtained. The change of fluorescence intensity with respect to the diffusion time is monitored. The above equation is used for the data analysis, where L represents the film thickness and t represents the average time for the acid to diffuse through the film. The diffusion constant is calculated to be at the order of 10^-10 cm²/s to 10^-12 cm²/s. All the experiments are conducted at room temperature and are valid only for acid vapor. With different film thickness, it was found that the acid diffuses through the film with a similar diffusion constant. The diffusion is faster with increased solvent residue in the film (controlled by spin coating speed). The theoretical computer modeling of the local acid concentration with respect to acid diffusion is also performed.

Proceedings Article | 7 July 1997 Paper

Diffusivity measurements in polymers: I. Lithographic modeling results

Chris Mack, Katherine Mueller, Allen Gardiner, Anwei Qin, Ralph Dammel, William Koros, C. Grant Willson

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275906

KEYWORDS: Lithography, Polymers, Photoresist materials, Quartz, Crystals, Scintillation

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Proceedings Article | 7 July 1997 Paper

Non-chemically amplified 248-nm resist materials

C. Grant Willson, Wang Yueh, Michael Leeson, Thomas Steinhaeusler, Christopher McAdams, Ralph Dammel, James Sounik, M. Aslam, Richard Vicari, Michael Sheehan

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275821

KEYWORDS: Deep ultraviolet, Absorbance, Analog electronics, Chromophores, Lithography, Chemically amplified resists, Ultraviolet radiation, Manufacturing, Lamps, Excimer lasers

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Remarkable progress has been made in the formulation of chemically amplified resists for deep-UV (DUV or 248 nm) lithography. These materials are now in general use in full scale manufacturing. One of the deterrents to rapid and universal adoption of DUV lithography has been the combination of high cost of ownership and a narrow process latitude when compared to conventional i-line process alternatives. A significant part of the high cost of the DUV process is associated with installing and maintaining special air handling equipment that is required to remove basic contaminants from the ambient. Manufacture process latitude demands this special air handling. The chemically amplified resists were developed originally to support mercury lamp powered exposure systems. The sensitivity realized by chemical amplification is required to enable useful productivity with such systems that generate very little DUV flux at the wafer plane. With the advent of high powered excimer laser based illumination systems for 248 nm steppers and step-and-scan systems, it is appropriate to re-examine the applicability of non-chemically amplified DUV resist systems. These systems are less sensitive but have the potential to offer both lower cost of ownership and improved process latitude. A series of photoactive compounds (PACs) have been synthesized and auditioned for use in the formulation of a non-chemically amplified 248 nm resist. The most promising of these materials are analogs of 3-oxo-3-diazocoumarin. This chromophore displays photochemistry that is analogous to that of the diazonaphthoquinones (DNQ) that are the basis of i-line resist formulations, but it bleaches at 248 nm. Several structural analogs of the chromophore have been synthesized and a variety of ballast groups have been studied with the goal of enhancing the dissolution inhibition properties of the molecule. The diazocoumarin PACs have been formulated with customized phenolic resins that were designed to provide the combination of optical transparency, dry etch resistance and the dissolution characteristics that are required for manufacturing applications. The resins are copolymers of poly(4-hydroxystyrene) and blends of these polymers with novolac.

Proceedings Article | 7 July 1997 Paper

Tailoring of a photoactive compound for non-chemically amplified 248-nm resist formulations

Michael Leeson, Adam Pawloski, Vrad Levering, Wang Yueh, C. Grant Willson

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275887

KEYWORDS: Chromophores, Photolysis, Deep ultraviolet, Picture Archiving and Communication System, Photochemistry, Sensors, FT-IR spectroscopy

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Proceedings Article | 7 July 1997 Paper

Refractive indices in thick photoresist films as a function of bake conditions and film exposure

Stanley Ficner, Ralph Dammel, Yvette Perez, Allen Gardiner, C. Grant Willson

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275885

KEYWORDS: Photoresist materials, Refractive index, Remote sensing, Semiconducting wafers, Prisms, Reticles, Astatine, Copper, Waveguides, Head-mounted displays

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Proceedings Article | 7 July 1997 Paper

Photoresist characterization for lithography simulation: III. Development parameter measurements

Clifford Henderson, Pavlos Tsiartas, Sanju Pancholi, Sajed Chowdhury, Katherine Dombrowski, C. Grant Willson, Ralph Dammel

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275882

KEYWORDS: Photoresist developing, Data modeling, Picture Archiving and Communication System, Diffusion, Refractive index, Photoresist materials, Lithography, Information operations, Semiconducting wafers, Silicon

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Proceedings Article | 7 July 1997 Paper

Photoresist materials: a historical perspective

C. Grant Willson, Ralph Dammel, Arnost Reiser

Proceedings Volume 3050, (1997) https://doi.org/10.1117/12.275921

KEYWORDS: Polymers, Deep ultraviolet, Printing, Photography, Photoresist developing, Photoresist materials, Coating, Lithography, Manufacturing, Image processing

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Proceedings Article | 7 July 1997 Paper

Influence of optical nonlinearities of the photoresist on the photolithographic process: basics

Andreas Erdmann, Clifford Henderson, C. Grant Willson, Wolfgang Henke

Proceedings Volume 3051, (1997) https://doi.org/10.1117/12.276032

KEYWORDS: Photoresist materials, Refractive index, Nonlinear optics, Beam propagation method, Lithography

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Proceedings Article | 7 July 1997 Paper

Influence of optical nonlinearities of the photoresist on the photolithographic process: applications

Andreas Erdmann, Clifford Henderson, C. Grant Willson, Wolfgang Henke

Proceedings Volume 3048, (1997) https://doi.org/10.1117/12.275810

KEYWORDS: Refractive index, Photoresist materials, Nonlinear optics, Absorption, Standards development, Photoresist processing, Phase shifts, Lithography, Imaging systems, Diffusion

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Proceedings Article | 7 July 1997 Paper

Novel functional nortricyclene polymers and copolymers for 248- and 193-nm chemically amplified resists

Qingshang Niu, Jean Frechet, Uzodinma Okoroanyanwu, Jeff Byers, C. Grant Willson

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275888

KEYWORDS: Polymers, Polymerization, Lithography, Resistance, Silicon, Metals, Etching, Chemically amplified resists, Excimer lasers, Chemistry

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Proceedings Article | 7 July 1997 Paper

Diffusivity measurements in polymers: IV. Acid diffusion in chemically amplified resists

Katherine Mueller, William Koros, Chris Mack, C. Grant Willson

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275837

KEYWORDS: Diffusion, Crystals, Polymers, Quartz, Chemically amplified resists, Lithography, Chemical analysis, Glasses, Extreme ultraviolet, Chemical reactions

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Proceedings Article | 7 July 1997 Paper

Design of a positive-tone water-soluble resist

Jennifer Havard, Jean Frechet, Dario Pasini, Brenda Mar, Shintaro Yamada, David Medeiros, C. Grant Willson

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275844

KEYWORDS: Coating, Polymers, Chemistry, Ultraviolet radiation, Photochemistry, Image processing, Electron beams, Imaging systems, Silicon, Semiconducting wafers

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Proceedings Article | 7 July 1997 Paper

Photoresist materials: a historical perspective

C. Grant Willson, Ralph Dammel, Arnost Reiser

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275826

KEYWORDS: Polymers, Deep ultraviolet, Printing, Photoresist developing, Photography, Photoresist materials, Coating, Lithography, Semiconducting wafers, Manufacturing