Patent ID: 9194817
Filing Date: 2015-11-24
Classification: G01N

Abstract:
1. A defect detection method comprising: irradiating light from a light source in an optical system and obtaining a plurality of optical images of a sample having a repeated pattern having a size smaller than a resolution of the optical system, while changing the conditions of the optical system; performing correction processing for the plurality of optical images with the use of at least one of noise filtering and convolution filtering; shifting a position of the other optical images based on any of the plurality of optical images, obtaining a relationship between shift amounts of the other optical images and a change of correlation of a gray scale value using base pattern noise between the plurality of optical images, and performing positional alignment of the plurality of optical images based on the shift amount obtained when the correlation is highest; and performing defect detection of the sample with the use of the plurality of optical images after the positional alignment.