Patent ID: 8737718

Claim:
A defect inspection apparatus comprising: an illumination optical system configured to irradiate an inspection subject, under a plurality of inspection conditions; a detection optical system configured to detect scattered light from the inspection subject irradiated by the illumination optical system, under the plurality of inspection conditions, and to obtain a plurality of images under the plurality of inspection conditions; and an image processing system that includes: a defect candidate detection unit configured to detect defect candidates with respect to a plurality of images obtained by the detection optical system, under the plurality of inspection conditions, respectively, by using a first threshold and a second threshold lower than the first threshold, and a post-inspection processing unit configured to execute a defect determination, by differentiating defects from noise, and by integrating features of the defect candidates with respect to the plurality of images obtained under the plurality of inspection conditions, wherein in the post-inspection processing unit: a defect candidate detected by the defect candidate detection unit is determined to be a defect when detected in at least one of the plurality of images obtained by the detection optical system, under the plurality of inspection conditions, by applying the first threshold, or alternatively, the defect is detected in all of the plurality of images obtained by the detection optical system, under the plurality of inspection conditions, by applying the second threshold, and a defect candidate is determined to be noise when the defect candidate is detected in less than all of the plurality of images obtained by the detection optical system, under the plurality of inspection conditions, by applying the second threshold.