Patent ID: 6798504
Filing Date: 2004-09-28
Classification: G01N

Abstract:
A surface inspection apparatus comprising:an optical system that irradiates a first and second light beams onto a same given position on a surface of a substrate to be inspected and receives scattered lights from the same given position on the surface of the substrate, but at different light reception angles, to thereby generate first and second light detection signals corresponding to the different light reception angles; and a processing device that sets a reference function defining a correlation in level value between said first and second light detection signals, makes a comparison between respective level values of said first and second light detection signals using the reference function as a comparison reference, and determines, on the basis of a result of the comparison, which of a plurality of different types possible defects present on the surface of the substrate, represented by the light detection signals, corresponds to, wherein the reference function is a predetermined function expressed as Y=f(X), and wherein the type of the possible defect as identified depending in whether the predetermined function Y, where X represents the level value of one of said first and second light detection signals, is greater or smaller than the level value of the other of said first and second light detection signals.