Patent ID: 7957926

Claim:
A system, comprising: a chamber adapted to receive at least one semiconductor wafer; a lamp heat source in communication with said chamber; a first temperature measuring device configured to detect radiation thermally emitted from a first location on the semiconductor wafer, the first location being positioned at a first radial distance from the center of the semiconductor wafer; and a second temperature measuring device configured to determine the temperature of the semiconductor wafer based on a temperature dependence of an optical property of the semiconductor wafer, the second temperature measuring device comprising at least one light source that radiates light energy onto a second location on the semiconductor wafer, the at least one light source configured to be controlled independently of the lamp heat source, the second temperature measuring device further comprising at least one light detector positioned to detect the light energy from the light source after the light energy has been transmitted through or reflected from the semiconductor wafer; wherein the second location is located at a second radial distance from the center of the semiconductor wafer, the difference between the first radial distance and the second radial distance being no greater than about 5 cm.