Patent ID: 6134011
Filing Date: 2000-10-17
Classification: G01J,G01N

Abstract:
An optical measurement system for evaluating a substrate, the system comprising:an intensity stabilized light source configured to generate a stabilized light beam,a polarizing element for polarizing the light beam emanating from the light source to provide a polarized light beam,an optical system for directing the polarized light beam to a particular location on the substrate,a controllable translatable assembly for moving the polarized light beam across at least a portion of the substrate such that the polarized light beam impinges upon multiple locations on the substrate,a position indicating means for determining the particular location on the substrate upon which the polarized light beam impinges,a detection system configured to evaluate light reflected from the particular locations on the substrate upon which the polarized light beam impinges, the detection system includinga polarization analyzing element for separating the light from the particular locations on the substrate into s-polarized light and p-polarized light,a first optical sensor measuring amplitude of the s-polarized light,a second optical sensor measuring amplitude of the p-polarized light, anda third optical sensor measuring reflection angle of the reflected light relative to the substrate, anda control system for compiling a data set correlating the measured amplitude of the s-polarized light, the p-polarized light, and the measured reflection angle with the particular location on the substrate upon which the polarized light beam impinges for determining changes in the substrate.