A run-to-run control algorithm based on timely and delayed mixed-resolution information

Abstract

In certain run-to-run (R2R) processes, timely accurate measurements are difficult to obtain due to slow laboratory measurement operations. Instead, only low-resolution categorical observations are observed online for important quality variables; continuous measurements for the same variables are provided after a specific amount of delay. Currently, most conventional R2R controllers cannot be applied if no continuous observations are available. It is therefore important to develop online algorithms for R2R process control based on mixed-resolution information that is partially timely and partially delayed. In this study, we take the lapping process in semiconductor manufacturing as an example and propose parameter estimation models with these mixed-resolution data for processes with the first-order autoregressive, AR(1), disturbance series. We also derive control strategies to generate recipes between production runs for better process control. The computational results of a performance evaluation show that the control performance of the proposed method is competitive compared to existing methods that are based on accurate measurements.

Keywords:

• run-to-run process control
• statistical process adjustment
• statistical process control

Acknowledgement

We greatly thank the editor and the anonymous referees for their very helpful comments which have significantly assisted us in improving this manuscript. This work was supported by National Natural Science Foundation of China (NSFC) under grants No. 70802034 and No. 71072012.