Temperature measurement in rapid thermal processing

The stringent process uniformity and repeatability requirements of future semiconductor processing demand continuing improvement in wafer temperature control during rapid thermal processing (RTP). The wafer itself is the most important and unpredictable variable in an RTP system, as its optical properties dominate its thermal response. Basic heat transfer models, which include the thermal radiative properties of wafers, have been used to evaluate several RTP temperature measurement and control schemes. Simple methods can deliver good repeatability in a production environment by relying on the integration of the wafer's spectral emissivity over a wide waveband.