Model-based control of rapid thermal processing systems

Tight control of the wafer temperature in rapid thermal processing (RTP) of semiconductor wafers is considered. Of the various techniques for controlling the temperature, model-based control has the potential for attaining the best performance. An identification of a state-space model based on the subspace-fitting technique results in an experiment-based model. Subsequently, a linear-quadratic Gaussian (LQG) controller is designed for an identified model. The identification technique and the controller are validated with experimental results