Patent ID: 9036143
Filing Date: 2015-05-19
Classification: G01N,G06T

Abstract:
1. An inspection apparatus comprising: a light source configured to emit light with which a sample is illuminated; a half-wave plate configured to transmit the light emitted from the light source; a branching element configured to branch the light transmitted through the half-wave plate; a first sensor and a second sensor configured to acquire an optical image of a pattern formed in the sample, sensing the branched light incident on the first sensor and the second sensor; a light quantity acquisition unit configured to acquire a light quantity ratio (1:A) of the second sensor to the first sensor using the optical image, and to obtain an angle θ of the half-wave plate such that the light quantity ratio becomes A:1; an angle controller configured to receive information on the angle θ from the light quantity acquisition unit to control an angle of the half-wave plate; a light source controller configured to receive information on each of light quantity values of the first sensor and the second sensor from the light quantity acquisition unit, and to control a light quantity of the light source such that each of the light quantity values becomes a target value; and a comparator configured to compare the optical image acquired by the first sensor to a standard image with respect to a pattern having a density of a predetermined value or more in the pattern, to compare the optical image acquired by the second sensor to the standard image with respect to a pattern having a density smaller than the predetermined value in the pattern, and to determine a place where a difference between the optical image acquired by the first sensor and the standard image or a difference between the optical image acquired by the second sensor and the standard image exceeds a threshold to be a defect.