Emissivity compensated pyrometry for specular silicon surfaces on the NIST RTP test bed

Abstract

Since pyrometric thermometry is a noncontact method, it has great promise as a technique for monitoring silicon wafers during rapid thermal processing (RTP). Absolute values of surface emissivity are required when making pyrometric temperature measurements. One approach to obtaining these values is the use of emissivity compensated pyrometry, where a reflectometer is integrated into the pyrometer to allow real-time emissivity measurement. While this technique has been successfully applied to metal organic chemical vapor deposition (MOCVD) of compound semiconductors, it has not been applied to RTP. Although such measurements require that the surface be a specular reflector, they promise real-time traceable temperature measurements that are independent of the nature of the wafer. Here we discuss measurement of wafer temperature for polished wafers and an initial attempt to measure a patterned wafer during heating inside the RTP test bed at the National Institute of Standards and Technology