Multivariable Feedback Control of Semiconductor Wafer Temperature

Rapid thermal processing (RTP) of semiconductor wafers involves processing single wafers in small reaction chambers. Powerful lamp arrays are used to heat wafers quickly. The nature of RTP makes control of wafer temperature a difficult problem; ensuring near-uniform temperature across the wafer is critical. After a brief introduction to RTP and the RTP temperature control problem, this paper presents a novel approach to the analysis of candidate sensor configurations for multi-actuator, multi-sensor feedback control systems needed to ensure small temperature error in the face of substantial disturbances.