SUSTENANCE OF OPTIMUM CD CONTROL PERFORMANCE

摘要

This paper describes a new method for the sustenance of CD control performance. It is based on the CD control stability and robustness theory and runs online to sustain the best achievable results over the long term. When performance degradation is detected, an automatic procedure is invoked to check the CD and MD process models, mapping, actuator response, and other control parameters. Results are validated and corrections applied to the control system. Robustness features of the controller are manipulated to sustain the optimality. Mill results are also discussed.