Patent ID: 7787115

Claim:
An optical apparatus for defect inspection, comprising: a stage for mounting a specimen; an illuminating optical system for irradiating an illumination light beam for inspection having predetermined incident angles on a surface of the specimen to form a beam spot on the specimen surface; a detection optical system for detecting a reflection light ray originating from the beam spot; a correction processing section which, when the specimen subject to correction is used as an inspection target, correlates an output from said detection optical system based on a scattering light ray from a standard particle of known size with the known size of standard particle stored at a corresponding position to prepare a correlation between an output of said detection optical system and a true value; and a signal processing section which, when the inspection specimen is used as the inspection target, converts an output from said detection optical system into a size of a defect on the basis of the correlation prepared by said correction processing section.