Patent ID: 7676078

Claim:
An inspection method for an illumination optical system of an exposure tool, comprising: coating a surface of an exposure target substrate with a resist film; placing a plurality of imaging components provided on a front surface of a photomask, the front surface deviating from an optical conjugate plane of a surface of the resist film; forming a plurality of inspection patterns of the resist film having a plurality of openings, by development after projecting exposure beams output from a plurality of effective light sources onto the resist film via the imaging components, each of the openings corresponding to each of the effective light sources, each of the inspection patterns corresponding to each of the imaging components, the effective light sources being placed on a different optical conjugate plane than the surface of the resist film; measuring one of the inspection patterns as a reference image, and processing the reference image so as to provide reference image data; measuring inspection images of the inspection patterns, and processing the inspection images with the reference image data so as to provide a plurality of inspection image data; and determining an abnormal inspection image by comparing the inspection image data with the reference image data.