Dr. ChangAn Wang Profile

Dr. ChangAn Wang

at ASML

SPIE Involvement:

Author

Publications (16)

Proceedings Article | 28 April 2023 Presentation + Paper

Presentation + Paper

A holistic approach to model-based stochastic-aware computational lithography

ChangAn Wang, Yongfa Fan, Mu Feng, Qian Xie, Jazer Wang, Chris Kaplan, Michael Crouse, Xiaoyang Li, Stephen Hsu, Peigen Cao, Yi-Hsing Peng, Stephen Chang, Jun Ye, Youping Zhang, Bin Cheng, Ken Yang, Leiwu Zheng, Jen-Shiang Wang, Austin Peng, Li-Hao Yeh, Cuiping Zhang, Rafael Howell, Alexander Tan, Yiqiong Zhao, Jun Lang, Xiaolong Zhang

Proceedings Volume 12494, 124940B (2023) https://doi.org/10.1117/12.2658508

KEYWORDS: Stochastic processes, Data modeling, Optical proximity correction, Line width roughness, Source mask optimization, Computational lithography, Semiconducting wafers, Modeling, Performance modeling, Photons

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Proceedings Article | 28 September 2021 Presentation

Presentation

Contour-based variability decomposition for stochastic band metrology

Thomas Wallow, Jiyou Fu, Jiao Liang, Jen-Shiang Wang, Jimmy Fan, Maxence Delorme, ChangAn Wang, Fahong Li, Vivek Jain, Rui Yuan

Proceedings Volume 11854, 118540E (2021) https://doi.org/10.1117/12.2601587

KEYWORDS: Metrology, Stochastic processes, Photomasks, Model-based design, Scanning electron microscopy, Line edge roughness, Optical lithography, Semiconducting wafers, Extreme ultraviolet, Wafer-level optics

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Proceedings Article | 22 February 2021 Presentation + Paper

Presentation + Paper

Stochastic defect criticality prediction enabled by physical stochastic modeling and massive metrology

ChangAn Wang, Peigen Cao, Maxence Delorme, Jen-Yi Wuu, Jiyou Fu, Fuming Wang, Bob Lin, Yiqiong Zhao, Yi-Hsing Peng, Yongfa Fan, Mu Feng, Bin Cheng, Jen-Shiang Wang, Mark Simmoms, Stefan Hunsche, Oliver Patterson, Kuo-Feng Pao, Abdalmohsen Elmalk, Kevin Gao, Ruochong Fei, Xuefeng Zeng, Xiaolong Zhang

Proceedings Volume 11609, 1160916 (2021) https://doi.org/10.1117/12.2584767

KEYWORDS: Stochastic processes, Pattern recognition, Semiconducting wafers, Wafer inspection, Inspection, Defect detection, Metrology, Failure analysis, Data modeling, Calibration

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Proceedings Article | 20 March 2019 Presentation + Paper

Presentation + Paper

Compact modeling of negative tone development resist with photo decomposable quencher

Ao Chen, Kar Kit Koh, Yee Mei Foong, Bradley Morgenfeld, Jun Chen, Sandra Lee, Xi Chen, Hesham Omar, Mu Feng, ChangAn Wang, Keith Gronlund, Jun Lang, James Guerrero, Yiqiong Zhao

Proceedings Volume 10961, 109610F (2019) https://doi.org/10.1117/12.2514784

KEYWORDS: Diffusion, SRAF, Photoresist processing, Calibration, Photo decomposable quencher, Semiconducting wafers, Process modeling, Performance modeling, 3D modeling, Error analysis

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Proceedings Article | 22 March 2018 Paper

Paper

Massive metrology using fast e-beam technology improves OPC model accuracy by >2x at faster turnaround time

Qian Zhao, Lei Wang, Jazer Wang, ChangAn Wang, Hong-Fei Shi, James Guerrero, Mu Feng, Qiang Zhang, Jiao Liang, Yunbo Guo, Chen Zhang, Tom Wallow, David Rio, Lester Wang, Alvin Wang, Jen-Shiang Wang, Keith Gronlund, Jun Lang, Kar Kit Koh, Dong Qing Zhang, Hongxin Zhang, Subramanian Krishnamurthy, Ray Fei, Chiawen Lin, Wei Fang, Fei Wang

Proceedings Volume 10585, 105852Q (2018) https://doi.org/10.1117/12.2299971

KEYWORDS: Metrology, Data modeling, Calibration, Optical proximity correction, Scanning electron microscopy, Image processing, Time metrology, Critical dimension metrology, Semiconducting wafers, Error analysis

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Classical SEM metrology, CD-SEM, uses low data rate and extensive frame-averaging technique to achieve high-quality SEM imaging for high-precision metrology. The drawbacks include prolonged data collection time and larger photoresist shrinkage due to excess electron dosage. This paper will introduce a novel e-beam metrology system based on a high data rate, large probe current, and ultra-low noise electron optics design. At the same level of metrology precision, this high speed e-beam metrology system could significantly shorten data collection time and reduce electron dosage. In this work, the data collection speed is higher than 7,000 images per hr. Moreover, a novel large field of view (LFOV) capability at high resolution was enabled by an advanced electron deflection system design. The area coverage by LFOV is >100x larger than classical SEM. Superior metrology precision throughout the whole image has been achieved, and high quality metrology data could be extracted from full field. This new capability on metrology will further improve metrology data collection speed to support the need for large volume of metrology data from OPC model calibration of next generation technology. The shrinking EPE (Edge Placement Error) budget places more stringent requirement on OPC model accuracy, which is increasingly limited by metrology errors. In the current practice of metrology data collection and data processing to model calibration flow, CD-SEM throughput becomes a bottleneck that limits the amount of metrology measurements available for OPC model calibration, impacting pattern coverage and model accuracy especially for 2D pattern prediction. To address the trade-off in metrology sampling and model accuracy constrained by the cycle time requirement, this paper employs the high speed e-beam metrology system and a new computational software solution to take full advantage of the large volume data and significantly reduce both systematic and random metrology errors. The new computational software enables users to generate large quantity of highly accurate EP (Edge Placement) gauges and significantly improve design pattern coverage with up to 5X gain in model prediction accuracy on complex 2D patterns. Overall, this work showed >2x improvement in OPC model accuracy at a faster model turn-around time.

Proceedings Article | 24 March 2017 Presentation + Paper

Presentation + Paper

Using heuristic optimization to set SRAF rules

ChangAn Wang, Norman Chen, Chidam Kallingal, William Wilkinson, Jian Liu, Alan Leslie

Proceedings Volume 10147, 1014706 (2017) https://doi.org/10.1117/12.2258233

KEYWORDS: SRAF, Printing, Semiconducting wafers, Matrices, Silicon, Lithography, Manufacturing, Image processing, Optical proximity correction, Genetic algorithms, Optimization (mathematics), Logic, Algorithm development, Photomasks

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Proceedings Article | 25 October 2016 Paper

Paper

The performance improvement of SRAF placement rules using GA optimization

Yan Xu, Bidan Zhang, Changan Wang, William Wilkinson, John Bolton

Proceedings Volume 9985, 99851C (2016) https://doi.org/10.1117/12.2241015

KEYWORDS: SRAF, Optical proximity correction, Printing, Semiconducting wafers, Computer simulations, Optimization (mathematics), Algorithm development, Model-based design, Genetic algorithms, Photomasks

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Proceedings Article | 31 March 2014 Paper

Paper

Rapid, accurate improvement in 3D mask representation via input geometry optimization and crosstalk

David Fryer, Michael Lam, Kostas Adam, Chris Clifford, Mike Oliver, Christian Zuniga, John Sturtevant, ChangAn Wang, Scott Mansfield

Proceedings Volume 9052, 905216 (2014) https://doi.org/10.1117/12.2046489

KEYWORDS: Photomasks, 3D modeling, Calibration, Source mask optimization, Data modeling, Semiconducting wafers, Performance modeling, Tolerancing, Metrology, Manufacturing

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Proceedings Article | 12 April 2013 Paper

Paper

Benchmarking study of 3D mask modeling for 2X and 1X nodes

ChangAn Wang, Chao-Chun Liang, Huikan Liu, Chidam Kallingal, Derren Dunn, James Oberschmidt, Jaione Tirapu Azpiroz

Proceedings Volume 8683, 86831A (2013) https://doi.org/10.1117/12.2011485

KEYWORDS: Photomasks, 3D modeling, Optical proximity correction, Performance modeling, Data modeling, Calibration, Critical dimension metrology, Metals, Error analysis, Diffraction

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Proceedings Article | 12 May 2005 Paper

Paper

65nm node gate pattern using attenuated phase shift mask with off-axis illumination and sub-resolution assist features

Gary Zhang, Mark Terry, Sean O'Brien, Robert Soper, Mark Mason, Won Kim, Changan Wang, Steven Hansen, Jason Lee, Joe Ganeshan

Proceedings Volume 5754, (2005) https://doi.org/10.1117/12.600409

KEYWORDS: SRAF, Critical dimension metrology, Optical proximity correction, Photomasks, Scanners, Lithographic illumination, Semiconducting wafers, Phase shifts, Lithography, Resolution enhancement technologies

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Proceedings Article | 28 May 2004 Paper

Paper

Characterization of ACLV for advanced technology nodes using scatterometer-based lens fingerprinting technique

ChangAn Wang, Guohong Zhang, Stephen DeMoor, Colin Tan, John Ilzhoefer, Chris Atkinson, Chad Wickman, Steve Hansen, Bernd Geh, Donis Flagello, Mark Boehm

Proceedings Volume 5377, (2004) https://doi.org/10.1117/12.535829

KEYWORDS: Critical dimension metrology, Monochromatic aberrations, Scanners, Fiber optic illuminators, Lithography, Metrology, Semiconducting wafers, Lithographic illumination, Control systems, Solids

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Proceedings Article | 26 June 2003 Paper

Paper

Evaluating scanner lens spherical aberration using scatterometer

Changan Wang, Gary Zhang, Colin Tan, Chris Atkinson, Mark Boehm, Jay Brown, David Godfrey, Michael Littau, Christopher Raymond

Proceedings Volume 5040, (2003) https://doi.org/10.1117/12.485437

KEYWORDS: Monochromatic aberrations, Spherical lenses, Scanners, Critical dimension metrology, Optical lithography, Semiconducting wafers, Phase measurement, Scatter measurement, Scanning electron microscopy, Distortion

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Proceedings Article | 26 June 2003 Paper

Paper

Characterization of optical proximity matching for 130-nm node gate line width

Sandra Zheng, Gary Zhang, ChangAn Wang, Shangting Detweiler

Proceedings Volume 5040, (2003) https://doi.org/10.1117/12.485431

KEYWORDS: Optical proximity correction, Critical dimension metrology, Metrology, Scanners, Scanning electron microscopy, Semiconducting wafers, Optical lithography, Scatterometry, Scatter measurement, Data modeling

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As IC density shrinks based on Moore’s law, optical lithography continually is scaled to print ever-smaller features by using resolution enhancement techniques such as phase shift mask, optical proximity correction (OPC), off-axis illumination and sub-resolution assistant features. OPC has been playing a key role to maximize the overlapping process window through pitch in the sub-wavelength optical lithography. As an important cost control measure, one general OPC model is applied to the full exposure field across multiple scanners. To implement this technique, optical proximity matching of line width across the field and across multiple tools turns out to be very crucial particularly at gate pattern. In addition, it is very important to obtain reliable critical dimension (CD) data sets with low noise level and high accuracy from the metrology tool. Otherwise, extracting the real scanner fingerprint in term of CD can not be achieved with precision in the order of 1nm~2nm. Scatterometry CD measurements have demonstrated excellent results to overcome this problem. The methodology of Scatterometry is emerging as one of the best metrology tool candidates in terms of gate line width control for technology nodes beyond 130nm. This paper investigates the sources of error that consume the CD budget of optical proximity matching for line through pitch (LTP). The study focuses on the 130nm technology node and uses experimental data and Prolith resist vector model based simulations. Scatterometer CD measurements of LTP are used for the first time and effectively correlated to lens aberrations and effective partial coherence (EPC) measurements which were extracted by Litel In-situ Interferometer (ISI) and Source Metrology Instrument (SMI). Implications of optical proximity matching are also discussed for future technology nodes. From the results, the paper also demonstrates the efficacy of scatterometer line through pitch measurements for OPC characterization.

Proceedings Article | 26 June 2003 Paper

Paper

Scatterometer-based scanner fingerprinting technique (ScatterLith) and its applications in image field and ACLV analysis

Changan Wang, Gary Zhang, Stephen DeMoor, Mark Boehm, Michael Littau, Christopher Raymond

Proceedings Volume 5040, (2003) https://doi.org/10.1117/12.485434

KEYWORDS: Monochromatic aberrations, Scanners, Critical dimension metrology, Image analysis, Lithography, Image processing, Error analysis, Optical lithography, Manufacturing, Semiconducting wafers

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The ability to accurately, quickly and automatically fingerprint the lenses of advanced lithography scanners has always been a dream for lithographers. This is truly necessary to understand error sources of ACLV, especially when the optical lithography is pushed into 130 nm regimes and beyond. This dream has become a reality at Texas Instruments with the help of scatterometry. This paper describes the development and characterization of the scatterometer based scanner lens testing technique (ScatterLith) and its application in 193 nm and 248 nm scanner lens fingerprinting. The entire procedure includes a full field exposure through focus in a micro stepping mode, scatterometer measurement of focus matrix, image field analysis and mapping of lens curvature, astigmatism, spherical aberration, line-through pitch analysis and ACLV analysis (i.e. across chip line width variation). ACLV has been directly correlated with image field deviation, lens aberration and illumination source errors. Examples are given to illustrate its applications in accurate focus monitoring with enhanced capability of dynamic image field and lens signature mapping for the latest ArF and KrF scanners used in manufacturing environment for 130nm node and beyond. Analysis of CD variation across a full scanner field is done through a step-by-step image field correction procedure. ACLV contribution of each image field error can be quantified separately. The final across slit CD signature is further analyzed against possible errors from illumination uniformity, illumination pupil fill, and higher order projection lens aberrations. High accuracy and short cycle time make this new technique a very effective tool for in-line real time monitoring and scanner qualification. Its fingerprinting capability also provides lithography engineers a comprehensive understanding of scanner performance for CD control and tool matching. Its extendibility to 90nm and beyond is particularly attractive for future development and manufacturing requirements.

Proceedings Article | 26 June 2003 Paper

Paper

Illumination pupil fill measurement and analysis and its application in scanner V-H bias characterization for 130-nm node and beyond

Gary Zhang, Changan Wang, Colin Tan, John Ilzhoefer, Chris Atkinson, Stephen Renwick, Steve Slonaker, David Godfrey, Catherine Fruga

Proceedings Volume 5040, (2003) https://doi.org/10.1117/12.485352

KEYWORDS: Scanners, Fiber optic illuminators, Critical dimension metrology, Semiconducting wafers, Metrology, Monochromatic aberrations, Printing, Data modeling, Reticles, Calibration

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A detailed characterization of across chip line width variation (ACLV) has been carried out on the latest Nikon scanners with a combination of advanced metrology techniques in Texas Instruments, including scatterometer-based image field and CD fingerprinting, lens aberrations measurement using a Litel in-situ interferometer, and illumination source imaging with a pin-hole camera. This paper describes the application of the above techniques in our investigation of the root causes for pattern CD bias between vertical and horizontal features. Illumination source radiance distribution is found sometimes to have a significant impact on V-H bias and the final overall ACLV on production wafers. Examples are given to demonstrate a comprehensive methodology that is used to quantitatively break down the overall CD errors and correlate them back to the basic optical and imaging components. It is shown through pupil-gram analysis that the ellipticity in partial coherence is typically within 1+/-1% for conventional illuminations settings on the advanced Nikon scanners while the uneven radiance distribution across the source plays a major role in V-H pattern CD bias. For scanners with low and uniform lens coma aberrations, the V-H bias after removing the contribution from image field errors is found to follow a linear relationship with the source radiance non-uniformity described also in terms of ellipticity. It is shown that radiance ellipticity is a bigger concern for off-axis illuminators. Tighter design rules patterned with off-axis illumination are more vulnerable to source radiance non-uniformity as well as lens aberrations. Illuminator induced V-H bias across the slit is compared to the signature caused by lens aberrations specifically uneven x,y-coma. Implications to exposure tool specification, control, and matching are further explored through experiments and lithography simulation for the current 130nm production and the future technology nodes in development.

Proceedings Article | 30 July 2002 Paper

Paper

New method to determine optimal photolithography process conditions using scatterometry

Changan Wang, Simon Chang, Mark Boehm

Proceedings Volume 4691, (2002) https://doi.org/10.1117/12.474578

KEYWORDS: Critical dimension metrology, Lithography, Scanning electron microscopy, Scanners, Scatter measurement, Photoresist processing, Optical lithography, Scatterometry, Monochromatic aberrations, Semiconducting wafers

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Showing 5 of 16 publications

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