True defect monitoring through repeating defect deletion

摘要

A method of deleting repeating defects having no effect on product yield of a wafer so that true defects on the wafer are more readily found. A wafer having a plurality of dies thereon is provided. The wafer is scanned to find any repeating defects. If the repeating defects have no effect on the product yield, the area around the repeating defects is marked out as "don't care" region. Another wafer scanning operation to find the true defects is subsequently conducted by scanning the region outside the "don't care" region.