Patent ID: 7275861

Claim:
A method for calibrating a pyrometer, comprising: placing a calibration target wafer in optical communication with an optical head via an optical head field of view, said calibration target including a first surface with a first eutectic-forming metal region at least partially surrounded by a second semiconductor region, said eutectic-forming metal having a known melting point when placed on said calibration target wafer, said optical head including a pyrometer, a source of reflectivity data, a processor, an emitter, and at least one photodetector in said optical head field of view; heating said calibration target wafer; moving said calibration target wafer relative to said optical head field of view via periodic motion, such that said optical head field of view regularly crosses said first eutectic-forming metal region and said second semiconductor region of said first surface of said calibration target wafer; obtaining the known melting point of said eutectic region of said calibration target from said source of reflectivity data; obtaining temperature data for said calibration target wafer in said second exposed semiconductor region from said pyrometer through said optical head field of view when said optical head field of view crosses said second semiconductor region; and, calibrating said pyrometer at said processor by correlating said reflectivity data and said temperature data to determine the actual temperature of said calibration target wafer when said melting point of aid eutectic region is reached, and adjusting the pyrometer based on said actual temperature.