Patent ID: 7200257
Filing Date: 2007-04-03
Classification: G03F

Abstract:
1. A method of inspecting a photomask, comprising: providing said photomask, said photomask comprising: a cell region, said cell region comprising one or more chip regions, each chip region comprising a pattern of opaque and clear sub-regions corresponding to features of an integrated circuit chip and one or more kerf regions, each kerf region comprising a pattern of opaque and clear sub-regions corresponding to features of an integrated circuit kerf; a clear region formed adjacent to a side of a copy region, said copy region comprising opaque and clear sub-regions that are copies of at least a part of said cell region; and an opaque region between said clear region and said cell region; performing an image scan of said copy region; performing an image scan of a portion of said cell region corresponding to said copy region; performing a comparison comprising a comparing of said image scan of said copy region and said image scan of said corresponding portion of said cell region; and determining locations of potential defects in said corresponding portion of said cell region based on said comparison or both determining said locations of potential defects in said corresponding portion of said cell region and determining corresponding locations of potential defects in said copy region based on said comparison.