Patent ID: 8330949

Claim:
A foreign substance inspection apparatus which includes a light projecting unit that projects light onto a surface of an object to be detected, a detector that detects an intensity of scattered light as a component of the light, projected onto the surface by the light projecting unit, in association with a two-dimensional coordinate position on the surface, and a processing unit that determines a particle size of a foreign substance present on the surface based on the detection result obtained by the detector, wherein a relationship between the intensity of the scattered light detected by the detector and the particle size of the foreign substance differs depending on the two-dimensional coordinate position on the surface, and the processing unit determines, a conversion curve to convert the intensity of the scattered light detected by the detector into the particle size of the foreign substance, in accordance with the two-dimensional coordinate position of the foreign substance detected by the detector, and converts the intensity of the scattered light detected by the detector into the particle size of the foreign substance using the determined conversion curve.