Semiconductor workpiece temperature measurement system

An apparatus for measuring a temperature of a workpiece, comprising:

• a workpiece orienter, comprising:
• a rotating pedestal on which a workpiece may be disposed;
• a shaft in communication with the rotating pedestal;
• a motor in communication with the shaft to rotate the shaft;
• a light emitter;
• exactly one light sensor;
• and
• a controller in communication with the light sensor, wherein the exactly one light sensor continuously measures an amount of light received from the light emitter as the workpiece is rotated one or more times and outputs a plurality of values to the controller, wherein the plurality of values varies as a function of rotational angle of the workpiece, and the controller determines a rotational orientation of the workpiece disposed between the light emitter and the exactly one light sensor based on the plurality of values received from the exactly one light sensor;
• and
• further wherein the controller also determines a temperature of the workpiece based on a diameter of the workpiece as determined by the plurality of values received from the exactly one light sensor.