Patent Document ID: 9255793
Application ID: 13521086
Patent Flag: 1

Claim One:
1. A defect inspection device comprising: irradiating unit which simultaneously irradiates different regions on a surface of a sample with illumination light under different optical conditions, on the surface of the sample patterns are repeatedly formed which are essentially having the same shape in design; detection unit which detects, for each of the different regions, light reflected from each region simultaneously irradiated with the illumination light under the different optical conditions by the irradiating unit; a first comparator which creates a first differential image from images of a first region under a first set of optical conditions; a second comparator which creates a second differential image from images of the first region under a second set of optical conditions; a differential image comparator which creates a third differential image based at least on the first differential image and the second differential image; a defect determination unit which determines defects based at least on feature quantities of the first differential image, feature quantities of the second differential image, and feature quantities of the third differential image; and defect classifying unit which classifies the defects.