Multi-tone rounding off amendment treatment manner and pattern survey instrument

摘要

A method and an apparatus are presented for correcting corner images of an integrated circuit pattern, for example, in an real image produced by optical scanning and deleting defects from the corner sections. Design data describing rectangular or trapezoidal patterns are expanded in a design data expansion section in multi-level gradations to produce a reference data for each pixel having resolution capability less than the inspection resolution capability. In a reference image forming section, based on the edge position of the real image, the reference data are processed to produce a reference image by rounding off the corner section and the line width while maintaining multi-level gradations. The boundary regions are blended using optical point spread functions obtained from the real image. IMAGE