Dr. Lei Zhuang Profile

Dr. Lei Zhuang

Senior Process Engineer at GLOBALFOUNDRIES Inc

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Author

Publications (10)

Proceedings Article | 22 October 2018 Presentation + Paper

Lithographic benefits and mask manufacturability study of curvilinear masks

Vivian Wei Guo, Fan Jiang, Jed Rankin, Ingo Bork, Alexander Tritchkov, Alexander Wei, Yuyang Sun, Srividya Jayaram, Larry Zhuang, Xima Zhang, Todd Bailey, James Word

Proceedings Volume 10810, 108100P (2018) https://doi.org/10.1117/12.2501973

KEYWORDS: Photomasks, SRAF, Printing, Lithography, Vestigial sideband modulation, Semiconducting wafers, Optical proximity correction, Manufacturing, Image quality, Image processing

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SPIE Journal Paper | 31 July 2018

Subresolution assist features impact and implementation in extreme ultraviolet lithography for next-generation beyond 7-nm node

Vivian Wei Guo, Fan Jiang, Alexander Tritchkov, Srividya Jayaram, Scott Mansfield, Larry Zhuang, Yuyang Sun, Xima Zhang, Todd Bailey, James Word

JM3, Vol. 18, Issue 01, 011003, (July 2018) https://doi.org/10.1117/12.10.1117/1.JMM.18.1.011003

KEYWORDS: SRAF, Photomasks, Metals, Extreme ultraviolet lithography, Personal protective equipment, Photovoltaics, Extreme ultraviolet, Image quality, Source mask optimization, Lithography

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The next-generation beyond 7-nm node potentially requires the implementation of subresolution assist features (SRAF) with extreme ultraviolet (EUV) lithography. This paper aims at providing a clear SRAF strategy for the next-generation beyond 7-nm node designs through a series of experiments. Various factors are considered, including stochastic effects, three-dimensional (3-D) mask effects, through-slit effects, aberrations, and pixelated source mask optimization (SMO) sources. We consider process variability bands with a variety of process conditions, including focus/dose/mask bias changes and also the normalized image log-slope/image log-slope as our objective functions, to determine what the best SRAF solution is for a set of test patterns. Inverse lithography technology is implemented to optimize both the main feature (MF) mask and SRAF placement, in particular, asymmetric SRAF placement to balance the 3-D mask effects. SRAF can potentially mitigate image shift through-focus, i.e., nontelecentricity, caused by EUV 3-D shadowing effect. This shadowing effect is pattern-dependent and contributes to the overlay variation. As we approach the next-generation beyond 7-nm node, this image shift can be more significant relative to the overlay budget, hence, we further investigate the impact of SRAF placement to the image shift. Moreover, the center of focus shift due to the large 3-D mask absorber thickness can be potentially mitigated by SRAF implementation. The common process window is significantly impacted by both the center of focus shift and the individual depth of focus and is evaluated using both metal and contact layer test cases. We study the source impact to SRAF insertion by experimenting with both a symmetric source (standard source) and an asymmetric source (SMO source). Finally, we understand the importance of using full flare map and full through-slit model (including aberration variation through-slit) in the MF correction. Furthermore, we evaluate the need of using full models in SRAF insertion. This is a necessary step to determine the strategy of SRAF implementation for the next-generation beyond 7-nm node.

Proceedings Article | 19 March 2018 Paper

SRAF requirements, relevance, and impact on EUV lithography for next-generation beyond 7nm node

Vivian Wei Guo, Fan Jiang, Alexander Tritchkov, Srividya Jayaram, Scott Mansfield, Larry Zhuang, Yuyang Sun, Xima Zhang, Todd Bailey

Proceedings Volume 10583, 105830N (2018) https://doi.org/10.1117/12.2297410

KEYWORDS: SRAF, Photomasks, Extreme ultraviolet lithography, Image quality, Source mask optimization, Optical proximity correction

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The next generation beyond 7nm node potentially requires the implementation of Sub-Resolution Assist Features (SRAF) with EUV lithography. This paper aims at providing a clear SRAF strategy for the next generation beyond 7nm node designs through a series of experiments. Various factors are considered, including: stochastic effects, 3D mask effects, through-slit effects, aberrations, and pixelated SMO sources.

EUV has 13.5nm as its wavelength, which is much smaller than the wavelength used in ArF lithography, and this gives very different imaging challenges compared to the ArF case. Due to the small wavelength and numerical aperture (NA) of the current EUV tools, depth of focus is not as significant of a concern as in DUV. Instead, EUV lithography is severely challenged by stochastic effects, which are directly linked to the slope of the intensity curve. DUV SRAF has been shown to be a powerful tool for improving NILS/ILS, as well as DOF, and here we explore how that translates into EUV imaging. In this paper, we consider Process Variability (PV) Bands with a variety of process conditions including focus/dose/mask bias changes and also the NILS/ILS as our objective functions, to determine what the best SRAF solution is for a set of test patterns. We have full investigations on both symmetric SRAF and asymmetric SRAF.

SRAF can potentially mitigate image shift through focus, i.e. non-telecentricity, caused by EUV 3D shadowing effect. This shadowing effect is pattern dependent and contributes to the overlay variation. As we approach the next generation beyond 7nm node, this image shift can be more significant relative to the overlay budget, hence we further investigate the impact of SRAF placement to the image shift. Moreover, the Center of Focus shift due to the large 3D mask absorber thickness can be potentially mitigated by SRAF implementation. The common process window is significantly impacted by both the center of focus shift and the individual depth of focus. We study the change by adding SRAF using both a symmetric source (standard source) and an asymmetric source (SMO source). Once SRAF is inserted for the test patterns, the common process window is plotted to compare the solutions with and without SRAF.

Finally, we understand the importance of using full flare map and full through slit model (including aberration variation through slit) in the main feature correction, but in this paper, we will further evaluate the need of using full models in SRAF insertion. This is a necessary step to determine the strategy of SRAF implementation for the next generation beyond 7nm node.

Proceedings Article | 16 March 2016 Paper

Integrated layout based Monte-Carlo simulation for design arc optimization

Dongbing Shao, Larry Clevenger, Lei Zhuang, Lars Liebmann, Robert Wong, James Culp

Proceedings Volume 9781, 978106 (2016) https://doi.org/10.1117/12.2218636

KEYWORDS: Monte Carlo methods, Semiconducting wafers, Design for manufacturability, Manufacturing, Semiconductors, Diffractive optical elements, Microelectronics, Protactinium, Process modeling

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Proceedings Article | 16 April 2011 Paper

Fundamental investigation of negative tone development (NTD) for the 22nm node (and beyond)

Guillaume Landie, Yongan Xu, Sean Burns, Kenji Yoshimoto, Martin Burkhardt, Larry Zhuang, Karen Petrillo, Jason Meiring, Dario Goldfarb, Martin Glodde, Anthony Scaduto, Matthew Colburn, Jason Desisto, Young Bae, Michael Reilly, Cecily Andes, Vaishali Vohra

Proceedings Volume 7972, 797206 (2011) https://doi.org/10.1117/12.882843

KEYWORDS: Photoresist developing, Photoresist materials, Polymers, Systems modeling, Semiconducting wafers, Optical lithography, Optical proximity correction, Photomasks, Etching, Nanoimprint lithography

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Proceedings Article | 16 March 2010 Paper

Demonstrating the benefits of source-mask optimization and enabling technologies through experiment and simulations

David Melville, Alan Rosenbluth, Kehan Tian, Kafai Lai, Saeed Bagheri, Jaione Tirapu-Azpiroz, Jason Meiring, Scott Halle, Greg McIntyre, Tom Faure, Daniel Corliss, Azalia Krasnoperova, Lei Zhuang, Phil Strenski, Andreas Waechter, Laszlo Ladanyi, Francisco Barahona, Daniele Scarpazza, Jon Lee, Tadanobu Inoue, Masaharu Sakamoto, Hidemasa Muta, Alfred Wagner, Geoffrey Burr, Young Kim, Emily Gallagher, Mike Hibbs, Alexander Tritchkov, Yuri Granik, Moutaz Fakhry, Kostas Adam, Gabriel Berger, Michael Lam, Aasutosh Dave, Nick Cobb

Proceedings Volume 7640, 764006 (2010) https://doi.org/10.1117/12.846716

KEYWORDS: Source mask optimization, Photomasks, Metals, Lithography, Optical proximity correction, Line edge roughness, Resolution enhancement technologies, Diffractive optical elements, Semiconducting wafers, Scanning electron microscopy

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Proceedings Article | 4 March 2010 Paper

OMOG mask topography effect on lithography modeling of 32nm contact hole patterning

Lei Yuan, Wenzhan Zhou, Larry Zhuang, Kwang Sub Yoon, Qun Ying Lin, Scott Mansfield

Proceedings Volume 7640, 76402K (2010) https://doi.org/10.1117/12.846547

KEYWORDS: Photomasks, SRAF, Lithography, Finite element methods, Opacity, Optical lithography, Glasses, Binary data, 3D modeling, Data modeling

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Proceedings Article | 16 March 2009 Paper

Overcoming the challenges of 22-nm node patterning through litho-design co-optimization

Martin Burkhardt, J. C. Arnold, Z. Baum, S. Burns, J. Chang, J. Chen, J. Cho, V. Dai, Y. Deng, S. Halle, G. Han, S. Holmes, D. Horak, S. Kanakasabapathy, R. H. Kim, A. Klatchko, C. S. Koay, A. Krasnoperova, Y. Ma, E. McLellan, K. Petrillo, S. Schmitz, C. Tabery, Y. Yin, L. Zhuang, Y. Zou, J. Kye, V. Paruchuri, S. Mansfield, C. Spence, M. Colburn

Proceedings Volume 7274, 727404 (2009) https://doi.org/10.1117/12.814433

KEYWORDS: Etching, Lithography, Printing, Optical lithography, Double patterning technology, Resolution enhancement technologies, Logic, Metals, Photomasks, Tolerancing

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Proceedings Article | 1 April 2008 Paper

32 nm logic patterning options with immersion lithography

K. Lai, S. Burns, S. Halle, L. Zhuang, M. Colburn, S. Allen, C. Babcock, Z. Baum, M. Burkhardt, V. Dai, D. Dunn, E. Geiss, H. Haffner, G. Han, P. Lawson, S. Mansfield, J. Meiring, B. Morgenfeld, C. Tabery, Y. Zou, C. Sarma, L. Tsou, W. Yan, H. Zhuang, D. Gil, D. Medeiros

Proceedings Volume 6924, 69243C (2008) https://doi.org/10.1117/12.784107

KEYWORDS: Photomasks, Double patterning technology, Logic, Lithography, Etching, Optical lithography, Optical proximity correction, Immersion lithography, Printing, Image processing

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The semiconductor industry faces a lithographic scaling limit as the industry completes the transition to 1.35 NA immersion lithography. Both high-index immersion lithography and EUV lithography are facing technical challenges and commercial timing issues. Consequently, the industry has focused on enabling double patterning technology (DPT) as a means to circumvent the limitations of Rayleigh scaling. Here, the IBM development alliance demonstrate a series of double patterning solutions that enable scaling of logic constructs by decoupling the pattern spatially through mask design or temporally through innovative processes. These techniques have been successfully employed for early 32nm node development using 45nm generation tooling. Four different double patterning techniques were implemented. The first process illustrates local RET optimization through the use of a split reticle design. In this approach, a layout is decomposed into a series of regions with similar imaging properties and the illumination conditions for each are independently optimized. These regions are then printed separately into the same resist film in a multiple exposure process. The result is a singly developed pattern that could not be printed with a single illumination-mask combination. The second approach addresses 2D imaging with particular focus on both line-end dimension and linewidth control [1]. A double exposure-double etch (DE2) approach is used in conjunction with a pitch-filling sacrificial feature strategy. The third double exposure process, optimized for via patterns also utilizes DE2. In this method, a design is split between two separate masks such that the minimum pitch between any two vias is larger than the minimum metal pitch. This allows for final structures with vias at pitches beyond the capability of a single exposure. In the fourth method,, dark field double dipole lithography (DDL) has been successfully applied to BEOL metal structures and has been shown to be overlay tolerant [6]. Collectively, the double patterning solutions developed for early learning activities at 32nm can be extended to 22nm applications.

Proceedings Article | 22 December 1997 Paper

Subwavelength transmission gratings and their applications in VCSELs

Stephen Chou, Steven Schablitsky, Lei Zhuang

Proceedings Volume 3290, (1997) https://doi.org/10.1117/12.298228

KEYWORDS: Vertical cavity surface emitting lasers, Polarization, Switching, Birefringence, Wave plates, Reflectivity, Amorphous silicon, Nanoimprint lithography, Diffraction gratings, Dielectric polarization

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