Patent attributes
The temperature of an object such as a semiconductor wafer that includes silicon can be determined based on the variation of the optical absorption coefficient of silicon with temperature. Temperatures above about 850° C., can be found by measuring phenomena that are affected by the magnitude of the optical absorption coefficient, especially at wavelengths >˜1 μm. Phenomena could include measuring light reflected, transmitted, emitted, absorbed, or scattered by the wafer and deriving the absorption coefficient from the measurements and then deriving temperature from the absorption coefficient. Temperature could be determined from a model relating phenomena directly to temperature, the model constructed based on absorption behavior and techniques discussed herein. The resulting temperature could be used to calibrate or control a rapid thermal processing chamber or other apparatus.
