1 March 1991 In-line supervisory control in a photolithographic workcell
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Proceedings Volume 1392, Advanced Techniques for Integrated Circuit Processing; (1991) https://doi.org/10.1117/12.48958
Event: Processing Integration, 1990, Santa Clara, CA, United States
In this paper we describe an in-line supervisory control system that uses statistical criteria in conjunction with feedback and feed-forward control in order to improve the capability of a photolithographic workcell. The three major components of the system namely process monitoring modeling and control were developed together and thus are perfectly compatible. The issue of monitoring is addressed by the development of metrology suitable for the economical in-line measurement of photoresist thickness and reflectance. Statistically designed experiments are used to develop equipment models that relate the process settings to in-line measurable responses. Finally the statistical process control concepts of the regression chart and acceptance chart are used as the basis of the criteria that initiate process control actions. A prototype of this system has been applied on the photolithographic sequence in the Berkeley microfabrication laboratory.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Zhi-Min Ling, Sovarong Leang, Costas J. Spanos, "In-line supervisory control in a photolithographic workcell", Proc. SPIE 1392, Advanced Techniques for Integrated Circuit Processing, (1 March 1991); doi: 10.1117/12.48958; https://doi.org/10.1117/12.48958

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