Image inspection system for defect detection

摘要

A defect detection system for classifying defects in reticles (such as used in the manufacture of integrated circuit wafers) is described. An inspection unit, scanning the reticle in real time, compares it with the correct form and inputs signals representing each defect and its position in a store. The stored defects are then used to direct the inspection unit to inspect each defect more slowly. The inspection unit classifies each defect as either being an "excess metal" or a "missing metal" defect, and corresponding signals are stored in respective additional stores. The signals stored in these stores are then further processed and compared with the desired form of the reticle so as to classify the "excess metal" defects as either being a "pin spot" defect, an "extension" defect or a "bridge-type" defect. Similarly, the "missing metal" defects are classified as either being a "pinhole" defect an "intrusion" defect or a "break-type" defect. A size measuring unit measures the size of each defect.