Patent ID: 8194969
Filing Date: 2012-06-05
Classification: G01N,G06K,G06T

Abstract:
1. An inspection apparatus for inspecting for an abnormality of a substrate having a pattern formed thereon comprising: an illumination system which irradiates said substrate with a light; a detection system which detects a light from said substrate; a first processor which makes a first image, a second image and a third image of a detection result of said detection system; a second processor which makes a first signed subtraction image by subtracting said second image from said first image; a third processor which makes a second signed subtraction image by subtracting said third image from said second image; a fourth processor which makes a subtraction image of said first signed subtraction image, and said second signed subtraction image by subtracting said second signed subtraction image from said first signed subtraction image; and a fifth processor which inspects said substrate by threshold-value processing of said subtraction image obtained by said fourth processor, wherein: a sign of an abnormal area in said first signed subtraction image has a reverse sign of a corresponding abnormal area in said second signed subtraction image, and a first coordinate of said abnormal area in said first signed subtraction image is substantially same as a second coordinate of said abnormal area in said second signed subtraction image.