Temperature Measurement and Control in a Rapid Thermal Processor

Abstract

ABSTRACTRapid Thermal Processing (RTP) of silicon or other semiconductor materials requires accurate measurement and control of temperature. In a typical RTP cycle, heating of the wafer takes place in seconds, making accurate control of the wafer temperature very critical. Non contact wafer temperature sensing is achieved using an optical pyrometer. Precise temperature control from 400° C to 1350° C is maintained with a closed loop control system consisting of an optical pyrometer and a computer. Sources of errors due to variations in emissivity as a function of wafer temperature, surface conditions and background radiation are discussed. Calibration of the system is achieved by using a thermocouple instrumented wafer.