High-Speed Wafer Temperature Control Approach of Step Chiller for Semiconductor Manufacturing Equipment

As the complexity of semiconductor manufacturing processes increases, various temperature control conditions are required to ensure the etching of various materials is optimized. Fast and precise temperature control is a key factor in the semiconductor production throughput and yield, making the development of a step chiller essential. This chiller mixes hot and cold coolants from two sources, enabling faster cooling/heating than can be achieved from a single source. In this paper, we propose a system identification and control strategy that can maximize the performance of step chillers for semiconductor production equipment, focusing on both speed and accuracy aspects. An approach of model reduction is utilized to transform the highly nonlinear time-varying delay system of the chiller into a linear time-invariant delay system. We then outline a model-based feedforward/feedback controller based on delay system control theory, and conclude with an experimental result demonstrating the effectiveness of the proposed control algorithm.