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Proceedings Paper

Multi-wavelength approach towards on-product overlay accuracy and robustness
Author(s): Kaustuve Bhattacharyya; Marc Noot; Hammer Chang; Sax Liao; Ken Chang; Benny Gosali; Eason Su; Cathy Wang; Arie den Boef; Christophe Fouquet; Guo-Tsai Huang; Kai-Hsiung Chen; Kevin Cheng; John Lin
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Paper Abstract

Success of diffraction-based overlay (DBO) technique1,4,5 in the industry is not just for its good precision and low toolinduced shift, but also for the measurement accuracy2 and robustness that DBO can provide. Significant efforts are put in to capitalize on the potential that DBO has to address measurement accuracy and robustness. Introduction of many measurement wavelength choices (continuous wavelength) in DBO is one of the key new capabilities in this area. Along with the continuous choice of wavelengths, the algorithms (fueled by swing-curve physics) on how to use these wavelengths are of high importance for a robust recipe setup that can avoid the impact from process stack variations (symmetric as well as asymmetric). All these are discussed. Moreover, another aspect of boosting measurement accuracy and robustness is discussed that deploys the capability to combine overlay measurement data from multiple wavelength measurements. The goal is to provide a method to make overlay measurements immune from process stack variations and also to report health KPIs for every measurement. By combining measurements from multiple wavelengths, a final overlay measurement is generated. The results show a significant benefit in accuracy and robustness against process stack variation. These results are supported by both measurement data as well as simulation from many product stacks.

Paper Details

Date Published: 13 March 2018
PDF: 8 pages
Proc. SPIE 10585, Metrology, Inspection, and Process Control for Microlithography XXXII, 105851F (13 March 2018); doi: 10.1117/12.2297420
Show Author Affiliations
Kaustuve Bhattacharyya, ASML Netherlands B.V. (Netherlands)
Marc Noot, ASML Netherlands B.V. (Netherlands)
Hammer Chang, ASML Taiwan Ltd. (Taiwan)
Sax Liao, ASML Netherlands B.V. (Netherlands)
Ken Chang, ASML Netherlands B.V. (Netherlands)
Benny Gosali, ASML Taiwan Ltd. (Taiwan)
Eason Su, ASML Netherlands B.V. (Netherlands)
Cathy Wang, ASML Taiwan Ltd. (Taiwan)
Arie den Boef, ASML Netherlands B.V. (Netherlands)
Christophe Fouquet, ASML Netherlands B.V. (Netherlands)
Guo-Tsai Huang, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)
Kai-Hsiung Chen, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)
Kevin Cheng, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)
John Lin, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)

Published in SPIE Proceedings Vol. 10585:
Metrology, Inspection, and Process Control for Microlithography XXXII
Vladimir A. Ukraintsev, Editor(s)

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