Patent ID: 6407808
Filing Date: 2002-06-18
Classification: G01N

Abstract:
A method for defect clustering in inspection patterns on the surface of a workpiece, said method comprising the steps of:(a) judging whether an occurrence probability distributions of clusters is known or not; (b) carrying out the following steps (c) and (d), if the occurrence probability distributions of clusters are known, and carrying out the following steps from (e) to (j), if the occurrence probability distributions of clusters are not known; (c) entering an occurrrence probability distributions of clusters; and (d) classifying the defects in clusters having the highest occurrence probability; (e) calculating a distance between optional defects in a characteristic space; (f) assuming that one defect forms one cluster respectively in an initial state; (g) setting a threshold; (h) combining some clusters in one cluster if the distance between nearest defects included in the clusters, is less than the threshold; (i) increasing the threshold somewhat; and (j) repeating steps (h) and (i) until the threshold exceeds a predetermined upper limit or the number of the clusters in less than a predetermined lower limit.