Model switching predictive control using bagging CAN2 and first-difference signals for temperature control of RCA cleaning solutions

The RCA cleaning method is the industry standard way to clean silicon wafers, where temperature control is important for a stable cleaning performance. However, it is difficult mainly because the RCA solutions cause nonlinear and time-varying exothermic chemical reactions. So far, the MSPC (model switching predictive controller) using the CAN2 (competitive associative net 2) has been developed and the effectiveness has been validated. However, we have observed that the control performance, such as the settling time and the overshoot, does not always improve with the increase of the number of learning iterations of the CAN2. To solve this problem, we introduce the bagging method for the CAN2 and first-difference signals for the MSPC. The effectiveness of the present method is shown by means of computer simulation.