REAL-TIME IMAGE PROCESSING ALGORITHM FOR VISUAL INSPECTION OF SEMICONDUCTOR WAFER PATTERNS.

The following general requirements are made in the visual inspection of the semiconductor wafer: (1) the candidates for the defect should automatically be detected from a complex multivalued pattern; and (2) only serious defects to the reliability of the element are extracted from those candidates. Such sophisticated decisions must be made with a high reliability and a high speed. This paper proposes a method for detecting serious defects as a means to cope with those requirements. The method is composed of the following two steps: (1)The defects are detected for each region by referring to the designed pattern. (2) The defect size and the pattern width (or interval) are measured by a certain distance transformation.