Patent ID: 8737676

Claim:
A defect estimation device comprising: an acquiring part which obtains a reference image and an optical image of a pattern formed on a mask; a simulator which utilizes the images obtained in the acquiring part, and estimates first images of the patterns obtained by transferring their images onto a substrate by a lithography process; a comparing unit which compares the first images with each other and when a difference exceeds at least one of threshold values, determines that there is a defect in the optical image of the pattern formed on the mask; a simulation repair circuit which simulates a repair to the optical image at a portion determined as defective by the comparing unit and, utilizing the reference image and the image obtained in the simulation repair circuit, estimates second images of the patterns obtained by transferring the images onto a substrate by the lithography process; and wherein, the second images are compared with each other to confirm whether the defect is eliminated by simulation repair.