Thermocouples are foten used as a calibration standard for rapid thermal processing. Although it has been recognized that the thermocouple temeprature can be different from the wafer temeprature, the magnitude of the temeprature difference is difficult to quantify. In this work, we present a simple analytical model to demonstrate the difference betwee nthe thermocouple temperature and the true wafer temperature. The resutls show that a large difference can exist betwee nthe thermocouple and the wafer temeprature. This is because the optical and thermophysical properties of the thermocouple and hte glue material are different from those of the wafer. The model resutls show that temperature measurement becomes more accurate if fien diameter thermocouple wires with very low emissivity are used.
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