Performance assessment of run-to-run control in semiconductor manufacturing based on IMC framework |
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Authors: | Liang Chen Mingda Ma David Shan-Hill Wang Shuqing Wang |
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Affiliation: | 1. State Key Laboratory of Industrial Control Technology , Institute of Advanced Process Control , Zhejiang University, Hangzhou, China;2. Center for Control and Guidance Technology , Harbin Institute of Technology , Harbin, China;3. Department of Chemical Engineering , National Tsing-Hua University , Hsin-Chu, Taiwan |
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Abstract: | The objective of this paper is to propose a universal methodology for performance assessment of run-to-run control in semiconductor manufacturing. The slope of the linear semiconductor process model is assumed to be known or subjected to mild plant/model mismatch. Based on an internal model control framework, analytical expressions of minimum variance performance (MVP) and best achievable performance (BAP) for a series of run-to-run control schemes are derived. In the methodology, closed-loop identification is utilised as the first step to estimate the noise dynamics via routine operating data, and numerical optimisation is employed as a second step to calculate the best achievable performance bounds of the run-to-run control loops. The validity of the methodology is justified by examples of performance assessment for EWMA control, double EWMA control and RLS-LT control, even under circumstances where the processes encounter model mismatch, metrology delay and more sophisticated noises. Several essential characteristics of run-to-run control are discovered by performance assessment, and valuable advice is offered to process engineers for improving the run-to-run control performance. Furthermore, a useful application example for online performance monitoring and optimal tuning of run-to-run controller demonstrates the advantage of the methodology. |
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Keywords: | performance assessment run-to-run control minimum variance performance best achievable performance IMC |
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