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Proceedings Paper

Sampling plan optimization for detection of lithography and etch CD process excursions
Author(s): Richard C. Elliott; Raman K. Nurani; Sung Jin Lee; Luis G. Ortiz; Moshe E. Preil; J. George Shanthikumar; Trina Riley; Greg A. Goodwin
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Paper Abstract

Effective sample planning requires a careful combination of statistical analysis and lithography engineering. In this paper, we present a complete sample planning methodology including baseline process characterization, determination of the dominant excursion mechanisms, and selection of sampling plans and control procedures to effectively detect the yield- limiting excursions with a minimum of added cost. We discuss the results of our novel method in identifying critical dimension (CD) process excursions and present several examples of poly gate Photo and Etch CD excursion signatures. Using these results in a Sample Planning model, we determine the optimal sample plan and statistical process control (SPC) chart metrics and limits for detecting these excursions. The key observations are that there are many different yield- limiting excursion signatures in photo and etch, and that a given photo excursion signature turns into a different excursion signature at etch with different yield and performance impact. In particular, field-to-field variance excursions are shown to have a significant impact on yield. We show how current sampling plan and monitoring schemes miss these excursions and suggest an improved procedure for effective detection of CD process excursions.

Paper Details

Date Published: 2 June 2000
PDF: 10 pages
Proc. SPIE 3998, Metrology, Inspection, and Process Control for Microlithography XIV, (2 June 2000); doi: 10.1117/12.386461
Show Author Affiliations
Richard C. Elliott, KLA-Tencor Corp. (United States)
Raman K. Nurani, KLA-Tencor Corp. (United States)
Sung Jin Lee, KLA-Tencor Corp. (United States)
Luis G. Ortiz, KLA-Tencor Corp. (United States)
Moshe E. Preil, KLA-Tencor Corp. (United States)
J. George Shanthikumar, Univ. of California/Berkeley (United States)
Trina Riley, Advanced Micro Devices, Inc. (United States)
Greg A. Goodwin, Advanced Micro Devices, Inc. (United States)

Published in SPIE Proceedings Vol. 3998:
Metrology, Inspection, and Process Control for Microlithography XIV
Neal T. Sullivan, Editor(s)

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