METHOD FOR PROCESSING MASK PATTERN IMAGE

摘要

PROBLEM TO BE SOLVED: To provide an image processing method having a means for setting an optimum threshold value in order to obtain binary picture which can be utilized to evaluation and measurement of a shape from a mask pattern image of a photomask having multigradation. SOLUTION: After dividing treatment of the mask pattern image is performed, setting judgment of the threshold value is performed by comparison between evaluation values calculated by using a discriminating analysis method at every divided region and reference values set in advance. By repeating this operation by division number times, a threshold value distribution table of whole image is produced. Then optimum threshold values of respective divided regions can be set by performing interpolation calculation of the threshold value distribution table by filter processing.