Patent ID: 8649591

Claim:
A pattern inspection apparatus comprising: a light source unit configured to generate and emit lights having different wavelengths; an illumination unit configured to apply the lights of the different wavelengths from the light source unit to the same region of a substrate in which an inspection target pattern is formed; a detection unit configured to detect reflected lights of a plurality of different wavelengths reflected by the substrate and then output a signal for each wavelength; an imaging unit configured to guide the reflected lights into the detection unit, and image the reflected lights on a detection surface of the detection unit; and an image processing unit configured to add the signal for each wavelength in association with an incident position of the detection surface to generate added image data comprising information on a wavelength and signal intensity, judging, by the added image data, whether the inspection target pattern has any defect, and when judging that the inspection target pattern has a defect, detecting the position of the defect in a direction perpendicular to the substrate.