Model-based control of rapid thermal processes

Model-based control for two rapid thermal processing systems has been performed. The condition number of the process influences the control strategies selected and the quality of control that can be achieved. For the Texas Instruments RTP system, a successively linearized quadratic dynamic matrix control (QDMC) strategy using a reduced set of outputs has been developed. Experimental results of the control strategy are presented and compared with internal model control with gain scheduling. The nonlinear controller discussed shows superior performance for the test case studied. The second RTP system designed by SEMATECH exhibits improved controllability. This system has the potential for tighter control of wafer temperature using gain scheduling