Patent ID: 7185311
Filing Date: 2007-02-27
Classification: G03F

Abstract:
1. A mask evaluating method comprising: calculating a killer defect rate function with respect to a simulative defect pattern including a pattern of photomask and a plurality of defects, the killer defect rate function representing a killer defect rate of the simulative defect pattern with respect to a desired density of the pattern and a desired size of the plurality of defects; calculating the number of killer defects in an inspection region of the photomask based on an area of the photomask inspection region, a pattern density in the inspection region, the killer defect rate function and a defect size distribution representing the number of defects per unit area to a defect size range acquired from a photomask manufacturing step; and evaluating the photomask based on the calculated number of the killer defects, wherein calculating the killer defect rate function comprises: forming a plurality of simulative defect patterns including a pattern and a plurality of defects, the plurality of simulative defect patterns differing from each other in at least one of a pattern density in the pattern and a size of the defects; calculating a killer defect rate for each of the plurality of simulative defect patterns; and calculating a killer defect rate function of the simulative defect patterns with respect to a desired pattern density in the pattern and a desired size of the defects by extrapolation using the killer defect rates of the plurality of simulative defect patterns.