Foreign substance inspection apparatus

摘要

A foreign substance inspection apparatus having a good signal to noise ratio with optical detection accuracy capable of detecting infinitesimal foreign substances, comprising a lighting portion to irradiate with an S polarized laser light beam and having the optical axis parallel to the substrate to be inspected, a detecting portion having an optical axis located in a position set by rotating the optical axis of the lighting portion by 120 DEG to 160 DEG with the point of intersection of the optical axis of the lighting portion and the surface to be inspected as the center of rotation so as to have an angle made with the surface to be inspected of 45 DEG or smaller to detect the area irradiated from the lighting portion by detecting the S polarized component in the scattered component from the foreign substances existing on the surface to be inspected and converting the S polarized component photoelectrically to a signal, and a signal processing portion to detect a foreign substance based on the signal outputted from the detecting portion.