Patent ID: 6360005
Filing Date: 2002-03-19
Classification: G01N,G06T

Abstract:
A system for inspection of a substrate, comprising:a scanner for scanning the substrate and providing a gray scale inspection signal; a reference database having a binary reference signal stored therein; a binarizer operable to binarize the gray scale inspection signal into a binary inspection signal; a binary to gray converter operable to convert the binary reference signal into a gray scale reference signal; a misalignment detection system operable to detect misalignment between the binary inspection and reference signals, and gray scale inspection and reference signals; a first defect detector operable to compare the binary inspection signal to the binary reference signal to detect substrate defects in a first range of sizes; and a second defect detector operable to separately compare the gray scale inspection signal to the gray scale reference signal to detect substrate defects in a second, different range of sizes, and including defects smaller than those detected by said first defect detector.