Patent ID: 7359545
Filing Date: 2008-04-15
Classification: G01N

Abstract:
1. A method for inspecting a photolithographically processed wafer, comprising the steps of: determining a first image signature of a golden wafer using a first lamp at a first intensity; determining a second image signature of the processed wafer using a second lamp at a second intensity; adjusting the first image signature based on a difference between the first intensity and the second intensity to generate an adjusted golden wafer signature wherein the difference is substantially equal to a respective value of a single color of the second image signature subtracted from a respective value of a single color of the first image signature; determining a respective multiple color signature of the golden wafer at each of a plurality of different setting values using the first lamp; calculating a color slope corresponding to a change in the respective color values for said single color and a plurality of other colors of said multiple color signature as compared to a change in the setting values; normalizing the slopes of each of said other colors with respect to said slope of said single color to generate an adjustment factor for each of said other colors; and generating a defect confidence value by comparing the second image signature with the golden wafer signature as adjusted by said adjustment factors.