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Proceedings Paper

Innovative techniques for improving overlay accuracy by using DCM (device correlated metrology) targets as reference
Author(s): Wei-Jhe Tzai; Simon C. C. Hsu; Howard Chen; Charlie Chen; Yuan Chi Pai; Chun-Chi Yu; Chia Ching Lin; Tal Itzkovich; Lipkong Yap; Eran Amit; David Tien; Eros Huang; Kelly T. L. Kuo; Nuriel Amir
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Paper Abstract

Overlay metrology performance as Total Measurement Uncertainty (TMU), design rule compatibility, device correlation and measurement accuracy are been challenged at 2x nm node and below. Process impact on overlay metrology becoming critical, and techniques to improve measurement accuracy becomes increasingly important. In this paper, we present an innovative methodology for improving overlay accuracy. A propriety quality metric, Qmerit, is used to identify overlay metrology measurement settings with least process impacts and reliable accuracies. Using the quality metric, an innovative calibration method, ASC (Archer Self Calibration) is then used to remove the inaccuracies. Accuracy validation can be achieved by correlation to reference overlay data from another independent metrology source such as CDSEM data collected on DCM (Device Correlated Metrology) hybrid target or electrical testing. Additionally, reference metrology can also be used to verify which measurement conditions are the most accurate. In this paper we bring an example of such use case.

Paper Details

Date Published: 21 April 2014
PDF: 7 pages
Proc. SPIE 9050, Metrology, Inspection, and Process Control for Microlithography XXVIII, 90501R (21 April 2014); doi: 10.1117/12.2046671
Show Author Affiliations
Wei-Jhe Tzai, United Microelectronics Corp. (Taiwan)
Simon C. C. Hsu, United Microelectronics Corp. (Taiwan)
Howard Chen, United Microelectronics Corp. (Taiwan)
Charlie Chen, United Microelectronics Corp. (Taiwan)
Yuan Chi Pai, United Microelectronics Corp. (Taiwan)
Chun-Chi Yu, United Microelectronics Corp. (Taiwan)
Chia Ching Lin, United Microelectronics Corp. (Taiwan)
Tal Itzkovich, KLA-Tencor Israel (Israel)
Lipkong Yap, KLA-Tencor Corp. (United States)
Eran Amit, KLA-Tencor Israel (Israel)
David Tien, KLA-Tencor Corp. (United States)
Eros Huang, KLA-Tencor Taiwan (Taiwan)
Kelly T. L. Kuo, KLA-Tencor Taiwan (Taiwan)
Nuriel Amir, KLA-Tencor Israel (Israel)

Published in SPIE Proceedings Vol. 9050:
Metrology, Inspection, and Process Control for Microlithography XXVIII
Jason P. Cain; Martha I. Sanchez, Editor(s)

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