Abstract: An emissivity compensating non-contact system for measuring the temperature of a semiconductor wafer. The system includes a semiconductor wafer emissivity compensation station for measuring the reflectivity of the wafer at discrete wavelengths to yield wafer emissivity in specific wavelength bands. The system further includes a measurement probe which is optically coupled to a semiconductor process chamber. The probe senses wafer self emission using one or more optical detectors and a light modulator. A background temperature determining mechanism independently senses the temperature of a source of background radiation. Finally, a mechanism calculates the temperature of the semiconductor wafer based on the reflectivity, self-emission and background temperature.

Abstract: A method and apparatus for measuring temperature by subjecting, to the temperature to be measured, a light-transmissive body of a material whose dimensions change in response to temperature, directing first rays of light from a light source through a first path including a predetermined distance of travel through the light-transmissive body, simultaneously directing second rays of light from the light source through a second path, parallel to the first path and of a linear length equal to that of the first path, but not including the predetermined distance of travel through the light transmissive body, and measuring the change in phases between the first and second light rays at the ends of the first and second paths, to thereby provide a measurement of the temperature to which the light-transmissive body was subjected.