Optimal feed-forward control for multizone baking in microlithography

An algorithm for feed-forward control to improve the performance of a multizone baking system used for lithography in semiconductor manufacturing is derived in this paper. It uses linear programming optimization of the heat transfer in a multizone bake plate to produce a predetermined heating sequence. The objective is to minimize the temperature disturbance induced by the placement of a wafer at ambient temperature on the hot multizone bake plate, and the improvement is verified experimentally.