Dr. Wei Liu Profile

Dr. Wei Liu

Principal Engineer at ASML

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Author

Publications (7)

Proceedings Article | 1 April 2013 Paper

Fast 3D thick mask model for full-chip EUVL simulations

Peng Liu, Xiaobo Xie, Wei Liu, Keith Gronlund

Proceedings Volume 8679, 86790W (2013) https://doi.org/10.1117/12.2010818

KEYWORDS: Photomasks, 3D modeling, Extreme ultraviolet lithography, Extreme ultraviolet, Deep ultraviolet, Finite-difference time-domain method, Semiconducting wafers, Lithography, Optical proximity correction, Reflectivity

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Proceedings Article | 23 March 2012 Paper

Model calibration and validation for pre-production EUVL

Gian Lorusso, Jeroen Van de Kerkhove, Peter De Bisschop, Eric Hendrickx, J. Jiang, D. Rio, W. Liu, H. Liu

Proceedings Volume 8322, 83221L (2012) https://doi.org/10.1117/12.916762

KEYWORDS: Calibration, Semiconducting wafers, Photomasks, Extreme ultraviolet lithography, Critical dimension metrology, Data modeling, Extreme ultraviolet, Metrology, Optical proximity correction, Scanners

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Proceedings Article | 14 October 2011 Paper

Mask aspects of EUVL imaging at 27nm node and below

Natalia Davydova, Eelco van Setten, Sang-In Han, Mark van de Kerkhof, Robert de Kruif, Dorothe Oorschot, John Zimmerman, Ad Lammers, Brid Connolly, Frank Driessen, Anton van Oosten, Mircea Dusa, Youri van Dommelen, Noreen Harned, Jiong Jiang, Wei Liu, Hoyoung Kang, Hua-yu Liu

Proceedings Volume 8166, 816624 (2011) https://doi.org/10.1117/12.896816

KEYWORDS: Reflectivity, Photomasks, Extreme ultraviolet, Extreme ultraviolet lithography, Apodization, Optical proximity correction, Photoresist processing, Scanners, Semiconducting wafers, Multilayers

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Proceedings Article | 2 April 2011 Paper

Imaging performance improvements by EUV mask stack optimization

Natalia Davydova, Eelco van Setten, Robert de Kruif, Dorothe Oorschot, Mircea Dusa, Christian Wagner, Jiong Jiang, Wei Liu, Hoyoung Kang, Hua-yu Liu, Petra Spies, Nils Wiese, Markus Waiblinger

Proceedings Volume 7985, 79850X (2011) https://doi.org/10.1117/12.884504

KEYWORDS: Photomasks, Reflectivity, Extreme ultraviolet, Critical dimension metrology, Extreme ultraviolet lithography, Semiconducting wafers, Optical proximity correction, 3D modeling, Data modeling, Reflection

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EUVL requires the use of reflective optics including a reflective mask. The mask contains a reflecting multilayer, tuned for 13.5 nm light, and an absorber which defines the dark areas. The EUV mask itself is a complex optical element with many more parameters than just the mask CD uniformity of the patterned features that impact the final wafer CDU. One of these parameters is absorber height. It has been shown that the oblique incidence of light in combination with the small wavelength compared to the mask topography causes a so-called shadowing effect manifesting itself particularly in an HV wafer CD offset. It was also shown that this effect can be essentially decreased by reducing absorber height and, in addition, it can be corrected by means of OPC. However, reduction of absorber height has a side effect that is an increased reflectivity of a mask black border resulting in field-to-field stray light due to parasitic reflections. One of the solutions to this problem is optical process correction (OPC) at field edges. In this paper we will show experimental data obtained on ASML EUV Alpha tool illustrating the black border effect and will demonstrate that this effect can be accurately predicted by Brion Tachyon EUV model allowing for a significant cross field CD uniformity improvement with mask layout correction technique. Also we show by means of rigorous 3D simulations that it is possible to improve the imaging performance significantly by performing global optimization of mask absorber height and mask bias in order to increase exposure latitude, decrease CD sensitivity to mask making variations such as CD mask error and absorber stack height variations. By sacrificing some exposure latitude throughput of exposure tool can be increased essentially and HV mask biasing can be reduced. For four masks with different absorber thicknesses from 44 nm to 87 nm it is proven experimentally by means of the EUV Alpha tool exposures of 27 nm L/S that the absorber thickness can be tuned to maximize exposure latitude. It was also proven that dose to size grows with absorber height and optimal feature bias depends on mask absorber height.

Proceedings Article | 13 March 2010 Paper

SMO for 28-nm logic device and beyond: impact of source and mask complexity on lithography performance

Seiji Nagahara, Kazuyuki Yoshimochi, Hiroshi Yamazaki, Kazuhiro Takeda, Takayuki Uchiyama, Stephen Hsu, Zhipan Li, Hua-yu Liu, Keith Gronlund, Terunobu Kurosawa, Jun Ye, Luoqi Chen, Hong Chen, Zheng Li, Xiaofeng Liu, Wei Liu

Proceedings Volume 7640, 76401H (2010) https://doi.org/10.1117/12.846473

KEYWORDS: SRAF, Source mask optimization, Photomasks, Metals, Diffractive optical elements, Lithography, Manufacturing, Electroluminescence, Fiber optic illuminators, Logic devices

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Proceedings Article | 23 September 2009 Paper

Accurate models for EUV lithography

Eric Hendrickx, Gian Lorusso, Jiong Jiang, Luoqi Chen, Wei Liu, Eelco Van Setten, Steve Hansen

Proceedings Volume 7488, 74882G (2009) https://doi.org/10.1117/12.829987

KEYWORDS: Data modeling, Semiconducting wafers, Critical dimension metrology, Calibration, Extreme ultraviolet, Photomasks, Extreme ultraviolet lithography, Optical proximity correction, Reticles, Point spread functions

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Proceedings Article | 23 September 2009 Paper

Feasibility study of the approach to flare, shadowing, optical and process corrections for EUVL OPC

Peter Nikolsky, Natalia Davydova, Koen van Ingen Schenau, Paul van Adrichem, Eric Hendrickx, Gian Lorusso, Jiong Jiang, Wei Liu, Huayu Liu

Proceedings Volume 7488, 74882N (2009) https://doi.org/10.1117/12.833527

KEYWORDS: Optical proximity correction, Extreme ultraviolet, Extreme ultraviolet lithography, Photomasks, Data modeling, Calibration, Semiconducting wafers, Optical calibration, Optical lithography, Scanners

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Showing 5 of 7 publications

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