Patent ID: 6894302
Filing Date: 2005-05-17
Classification: G01N

Abstract:
1. A surface inspection apparatus comprising: a stage on which an inspection target is placed; an illumination optical system having an epi-illumination system for epi-illuminating the inspection target placed on the stage and a slant illumination system for slant-illuminating a surface of the inspection target; a detection optical system having a first converging optical system for converging first scattered light that comes in a direction of a first desired angle with respect to the surface of the inspection target out of the first reflected light emitted from the inspection target epi-illuminated by means of the epi-illumination system of the illumination optical system and the second scattered light that comes in the direction of the first desired angle out of second reflected light emitted from the inspection target slant-illuminated by means of the slant illumination system of the illumination optical system, and having a first photoelectric conversion means for receiving the first and second scattered lights converged by means of the first converging optical system to thereby converting the received lights to first and second luminance signals; a comparison discrimination unit for discriminating a defect on the inspection target based on a relation between the first luminance signal and the second luminance signal that have been converted by means of the photoelectric conversion means of the detection optical system; and an output unit for supplying the result obtained by means of the comparison discrimination unit; wherein the detection optical system has a second converging optical system and a second photoelectric conversion means additionally, the second converging optical system converges third scattered light that comes in an angular direction lower than the first scattered light out of the first reflected light reflected from the inspection target that is epi-illuminated and fourth scattered light that comes in an angular direction lower than the second scattered light out of the second reflected light reflected from the inspection target that is slant-illuminated, and the second photoelectric conversion means receives the third and fourth scattered lights converged by means of second converging optical system and converts the received lights to third and fourth luminance signals respectively.