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Proceedings Paper

Advanced method for run-to-run control of photolithography overlay registration in high-mix semiconductor production
Author(s): Anthony J. Toprac; Yang Wang
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Paper Abstract

The application of overlay run-to-run control in high-mix production fabs (such as development fabs, ASIC fabs or foundries) encounters some unique problems. A new observer algorithm called JADETM (Just-in-Time Adaptive Disturbance Estimation) was developed to solve the high-mix run-to-run control problem. JADE uses recursive weighted least-squares parameter estimation to identify the contributions to variation that are dependent upon tool, product, reference tool, and reference reticle. With the JADE Observer algorithm, run-to-run controllers use all available feedback data independent of the length of time since a particular product was processed. The application of JADE, compared to traditional control techniques, will be demonstrated on high and low-mix fab lithography overlay data. This comparison illustrates the degradation of the typical streamline observer formulation under high-mix operation, with an actual worsening of overlay control relative to open-loop (no run-to-run control) operation. In contrast, the JADE algorithm control performance, while matching the typical streamline formulation at low-mix operation, will be shown to be unaffected under very high-mix photolithography operation.

Paper Details

Date Published: 17 May 2005
PDF: 8 pages
Proc. SPIE 5755, Data Analysis and Modeling for Process Control II, (17 May 2005); doi: 10.1117/12.599733
Show Author Affiliations
Anthony J. Toprac, Yield Dynamics, Inc. (United States)
Yang Wang, Yield Dynamics, Inc. (United States)

Published in SPIE Proceedings Vol. 5755:
Data Analysis and Modeling for Process Control II
Iraj Emami, Editor(s)

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