Calibration of a low-temperature cable-less lightpipe pyrometer on the NIST post-exposure bake test bed

The advent of the cable-less lightpipe radiation thermometer (CLRT) has resulted in a significant improvement in the accuracy of lightpipe radiation thermometer calibrations and measurements. CLRT systems show great promise in noncontact measurements by the elimination of the uncertainties caused by the long fiber optic cables and their connections and by the extension of the spectral range to handle low-temperature applications down to room temperature. A CLRT was first calibrated with the oil-bath and water-bath blackbody sources from 40degC to 180degC. Then the CLRT was compared to thin-film thermocouples and platinum resistance thermometers on a silicon wafer heated in a post-exposure bake (PEB) test bed. Comparison of the CLRT with both the blackbody and thermocouple standards provides confidence in using CLRTs and allows researchers to continue research into improving the accuracy and feasibility of applying CLRTs in semiconductor processing