Dr. Hao Mei Profile

Dr. Hao Mei

at KLA China

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Author

Publications (3)

Proceedings Article | 26 March 2019 Paper

Improved accuracy and robustness for advanced DRAM with tunable multi-wavelength imaging and scatterometry overlay metrology

Honggoo Lee, Sangjun Han, Minhyung Hong, Jieun Lee, Dongyoung Lee, Ahlin Choi, Chanha Park, Dohwa Lee, Seongjae Lee, Jungtae Lee, Jeongpyo Lee, DongSub Choi, Sanghuck Jeon, Zephyr Liu, Hao Mei, Tal Marciano, Eitan Hajaj, Lilach Saltoun, Dana Klein, Eran Amit, Anna Golotsvan, Wayne Zhou, Eitan Herzel, Roie Volkovich, John Robinson

Proceedings Volume 10959, 109591E (2019) https://doi.org/10.1117/12.2515015

KEYWORDS: Overlay metrology, Semiconducting wafers, Metrology, Scatterometry, Wafer-level optics, Manufacturing, Quality measurement, Imaging systems, Scanning electron microscopy, Diffractive optical elements

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Overlay process control is a critical aspect of integrated circuit manufacturing. Advanced DRAM manufacturing overlay error budget approaches the sub-2nm threshold, including all sources of overlay error: litho processing, non-litho processing, metrology error, etc. Overlay measurement quality, both for accuracy and robustness, depends on the metrology system and its recipe setup. The optimal configuration depends on the layer and materials involved. Increased flexibility of metrology setup is of paramount importance, paired with improved methods of recipe optimization.

Both optical image-based overlay (IBO) and scatterometry diffraction overlay (SCOL®) are necessary tools for overlay control. For some devices and layers IBO provides the best accuracy and robustness, while on others SCOL provides optimum metrology. Historically, wavelength selection was limited to discrete wavelengths and at only a single wavelength. At advanced nodes IBO and SCOL require wavelength tunability and multiple wavelengths to optimize accuracy and robustness, as well as options for polarization and numerical aperture (NA). In previous studies^1,2,3 we investigated wavelength tunability analysis with landscape analysis, using analytic techniques to determine the optimal setup. In this report we show advancements in the landscape analysis technique for IBO through both focus and wavelength, and comparisons to SCOL. A key advantage of imaging is the ability to optimize wavelength on a per-layer basis. This can be a benefit for EUV layers in combination with those of 193i, for example, as well as other applications such as thick 3D NAND layers. The goal is to make accurate and robust overlay metrology that is immune from process stack variations, and to provide metrics that indicate the quality of metrology performance. Through both simulation and on-wafer advanced DRAM measurements, we show quantitative benefits of accuracy and robustness to process stack variability for IBO and SCOL applications.

Methodologies described in this work can be achieved using Archer™ overlay metrology systems, ATL™ overlay metrology systems, and 5D Analyzer® advanced data analysis and patterning control solution.

Proceedings Article | 26 March 2019 Presentation + Paper

Process drift compensation by tunable wavelength homing in scatterometry-based overlay

Kun Gao, Pedro Herrera, Vidya Ramanathan, Victoria Naipak, Meng Wang, Renan Milo, Tal Yaziv, Nir BenDavid, Chen Dror, Hao Mei, Weihua Li, Xindong Gao, Linfei Gao, Md. Motasim Bellah, Karsten Gutjahr, Dongyue Yang, Cheuk Wun Wong, Xueli Hao, Tony Joung, DeNeil Park, Yue Zhou, Abhishek Gottipati

Proceedings Volume 10959, 1095906 (2019) https://doi.org/10.1117/12.2514548

KEYWORDS: Overlay metrology, Scatterometry, Process control

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Proceedings Article | 26 March 2019 Paper

Process monitoring and control with tunable wavelength overlay coupled with simulation-to-measurement analysis

Pedro Herrera, Kun Gao, Chen Dror, Eitan Hajaj, Alon Alexander Volfman, Raviv Yohanan, Vidya Ramanathan, Victoria Naipak, Renan Milo, Tal Yaziv, Nir BenDavid, Meng Wang, Hao Mei, Weihua Li, Xindong Gao, Dongyue Yang, Cheuk Wun Wong, Karsten Gutjahr, Xueli Hao, Tony Joung, Md. Motasim Bellah, DeNeil Park, Yue Zhou, Abhishek Gottipati

Proceedings Volume 10959, 1095928 (2019) https://doi.org/10.1117/12.2514725

KEYWORDS: Overlay metrology, Metrology, Process control, Semiconducting wafers, Inspection, Optical filters, Polarization, Modeling and simulation, Scatterometry

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