Device processing involving an optical interferometric thermometry

Abstract

A method for fabricating a semiconductor device, which involves a technique for monitoring the temperature of the semiconductor substrate in which the device is formed, is disclosed. In accordance with the inventive technique, light, to which the substrate is substantially transparent, is impinged upon the substrate, and the intensity of either the reflected or transmitted light is monitored. If, for example, the intensity of the reflected light is monitored, then this intensity will be due to an interference between the light reflected from the upper surface of the semiconductor substrate and the light transmitted through the substrate and reflected upwardly from the lower surface of the substrate. If the temperature of the substrate varies, then the optical path length of the light within the substrate will vary, resulting in a change in the detected intensity. By comparing the detected intensity with intensities corresponding to known temperature variations, the temperature of the substrate is readily determined.

Dependencies are inferred from the claim text.