Temperature control of wafer in semiconductor manufacturing systems by MR-ILQ design method

We consider control system synthesis for temperature control of a wafer in the semiconductor manufacturing system by using model reference inverse linear quadratic (abbreviated as MR-ILQ) control, which was proposed by the third and fourth authors [S. Kunimatsu and T. Fujii, 2003], as one of its significant applications in the industry process. First, we apply the subspace method [P.V. Overschee and B.D. Moor, 1994], [M. Verhaegen, 1994] to obtain a mathematical model described by multi-input multi-output state space representations for temperature dynamics of the wafer. Second, we design a robust servo system for tracking a step reference input without steady state error based on the MR-ILQ design method. Since this method yields not only robust steady state tracking but also robust transient tracking, it is possible to design a temperature control system with higher robust performance. Third, we show the efficiency of the above control system synthesis by experiment.