Dr. Kafai Lai
Adjunct Professor at Univ. of Hong Kong
SPIE Involvement:
Conference Program Committee | Author | Editor | Instructor
Area of Expertise:
Photolithography , imaging modeling , OPC , Design technology Co-optimization , Source Mask Optimization , Photonics
Publications (53)

Proceedings Article | 26 March 2019 Presentation + Paper
Chi-Chun Liu, Richard Farrell, Kafai Lai, Yann Mignot, Eric Liu, Jing Guo, Yasuyuki Ido, Makoto Muramatsu, Nelson Felix, David Hetzer, Akiteru Ko, John Arnold, Daniel Corliss
Proceedings Volume 10958, 109580L (2019) https://doi.org/10.1117/12.2515862
KEYWORDS: Metals, Critical dimension metrology, Etching, Directed self assembly, Optical lithography, Back end of line, Lithography, Overlay metrology

Proceedings Article | 6 September 2018 Paper
Balint Meliorisz, Kafai Lai, Ulrich Welling, Hans-Jürgen Stock, Sajan Marokkey, Thomas Muelders, Jing Sha, Chi-chun Liu, Cheng Chi, Jing Guo, Clifford Osborn, Jaime Morillo, Wolfgang Demmerle, Derren Dunn
Proceedings Volume 10586, 105860R (2018) https://doi.org/10.1117/12.2297344
KEYWORDS: Metals, Directed self assembly, Critical dimension metrology, Calibration, Error analysis, Etching, Computer simulations, Process modeling, Optical lithography, Extreme ultraviolet lithography

Proceedings Article | 28 March 2018 Paper
Proceedings Volume 10584, 105840L (2018) https://doi.org/10.1117/12.2297365
KEYWORDS: Etching, Critical dimension metrology, Metals, Directed self assembly, Oxides, Back end of line, Dielectrics, Scanning electron microscopy, Tin, Lithography

Proceedings Article | 27 April 2017 Presentation + Paper
Kafai Lai, Balint Meliorisz, Thomas Muelders, Ulrich Welling, Hans-Jürgen Stock, Sajan Marokkey, Wolfgang Demmerle, Chi-Chun Liu, Cheng Chi, Jing Guo
Proceedings Volume 10144, 101440H (2017) https://doi.org/10.1117/12.2260379
KEYWORDS: 3D modeling, Calibration, Data modeling, Optical lithography, Nanotechnology, Very large scale integration, System on a chip, Logic, Research facilities

Proceedings Article | 13 April 2017 Presentation + Paper
Proceedings Volume 10146, 101460Q (2017) https://doi.org/10.1117/12.2260454
KEYWORDS: Etching, Directed self assembly, Polymethylmethacrylate, Critical dimension metrology, Picosecond phenomena, Oxides, Scanning electron microscopy, Optical lithography, Extreme ultraviolet, Metals

Showing 5 of 53 publications
Proceedings Volume Editor (4)

SPIE Conference Volume | 27 April 2015

SPIE Conference Volume | 28 April 2014

SPIE Conference Volume | 26 April 2013

SPIE Conference Volume | 25 April 2012

Conference Committee Involvement (25)
DTCO and Computational Patterning III
26 February 2024 | San Jose, California, United States
DTCO and Computational Patterning II
27 February 2023 | San Jose, California, United States
SPIE Advanced Lithography + Patterning
26 February 2023 | San Jose, United States
DTCO and Computational Patterning
26 April 2022 | San Jose, California, United States
SPIE Advanced Lithography + Patterning
24 April 2022 | San Jose, United States
Showing 5 of 25 Conference Committees
Course Instructor
SC887: Modeling of Exposure Tools for OPC and Tooling Analysis
This course provides attendees with a basic working knowledge of modeling advanced exposure tools, with an emphasis on the optical chains. The course concentrates on the physics and working principles, as well as methodologies to analyze and model the whole optical chain of the exposure system (from illumination source to wafer space) using OPC software. This helps to bridge the communication between exposure tool engineers, lithography process engineers and OPC/RET/SMO engineers to improve lithography process in an integrated sense. You will become fluent with how one designs, analyzes, and models exposure systems for advanced ultrahigh NA immersion and dry lithography and advanced illumination, across a range of modern-day lithography practices.
SC1132: Computational Basis for Advanced Lithography Techniques
This course provides attendees with a definition and underling concepts of Computational Lithography, which is comprised of lithographic modeling and advanced pattern correction techniques. It is designed to bridge the communication of exposure tool engineers, lithography process engineers, metrology engineers and OPC/RET/SMO engineers to improve lithography process in an integrated sense. You will become familiar with the Computational Lithography framework and understand how the evolution of simple models and advanced pattern correction techniques to nowadays’ complicated yet powerful tools. An understanding of the fundamentals will allow lithographers to achieve optimum mask pattern for more robust lithography. This course will focus on both the imaging modeling and pattern correction methodology for novel patterning techniques such as Extreme UV (EUV), Directed Self-Assembly (DSA) and self-aligned multiple patterning. The unique computational features (Rigorous simulation, Mask decomposition, OPC, SMO, stochastic effect mitigation) of these novel techniques will be contrasted with traditional DUV lithography. A review of the emergence of Machine Learning based computational Lithography techniques targeted to improve efficiency for full-chip application will be given. The course concentrates on the physics and working principles, as well as methodologies, to develop the new computational infrastructure. Some basic issues in Design Technology Co-Optimization with respect to EUV, DSA etc. are also discussed.
SC1066: Practical Modeling and Computational Lithography
This course provides attendees with a definition and basic working knowledge of Computational Lithography, which is comprised of lithographic modeling and advanced pattern correction techniques. It is designed to bridge the communication of exposure tool engineers, lithography process engineers and OPC/RET/SMO engineers to improve lithography process in an integrated sense. You will become familiar with the Computational Lithography framework and fluent with how one develop models for advanced pattern correction techniques and apply them to achieve optimum mask pattern for more robust lithography. The modeling portion of the course covers the modeling of entire optical chain with wavelengths from DUV to EUV, and includes novel patterning techniques such as Directed Self Assembly (DSA). The advanced patterning portion of the course includes techniques such as OPC, SMO, Large Scale Source Optimization, and mask decomposition methodology. The course concentrates on the physics and working principles, as well as methodologies, to analyze and model the entire optical chain from illumination source to wafer space using OPC software. Fundamental principles of Advanced Pattern Correction methods are described and compared. Some basic issues in Design Technology Co-Optimization are discussed.
SC706: Imaging and Optics Fundamentals in Advanced Lithography
Optical imaging in microlithography involves the physical formation of sub-micron structures within a photosensitive material for subsequent transfer into underlying films or substrates. Since the optical exposure systems used in lithography are some of the most advanced and complex optical instruments ever built, they involve ever more complex illuminator designs, nearly aberration free lenses, and hyper numerical apertures approaching unity and beyond. Fortunately, the lithography community has risen to the challenge by devising many inventive methods to characterize and optimize exposure systems. Moreover, the advanced use of simulation not only ties together characterization data to form a cohesive picture of exposure system capability, but it allows for a shorter time to development if the appropriate model calibration is successfully used. The imaging theory and models that are subsequently used in this industry, either in commercial or in-house simulation packages, have successively evolved in complexity with each new generation of the optics, but can seem very complicated to the uninitiated. This course will cover and explain the fundamentals behind imaging and optics in state-of-the-art microlithography. The basic optical concepts will be explained, including hyper-NA, polarization, and immersion optics. A systematic, step-by-step construction of partial coherent imaging models will be developed for vector and scalar assumptions. The description is enhanced by simple application examples to allow these models to be easily understood. Additional techniques are described that reduce the complexity of these models to allow for the formation of exposure tool performance prediction.
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