 Image Number 4 for United States Patent #6375348.
A system and method for determining the reflectivity of a workpiece during processing in a heating chamber of a thermal processing apparatus. The system first determines directly the reflectivity of the workpiece outside of the heating chamber of the thermal processing apparatus, and then determines the reflectivity of the workpiece during processing within the heating chamber of the thermal processing apparatus by correlating the ex situ wafer reflectivity with the intensity of the radiation reflected from the wafer within the heating chamber.
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