Patent ID: 7260256
Filing Date: 2007-08-21
Classification: G06T

Abstract:
1. A method of inspecting a specimen having plural chips, each of the chips having plural patterns, comprising the steps of: imaging a first area of a chip to obtain plural images of plural patterns in the first area; comparing an image of a pattern in the first area among the plural images obtained at the imaging step with plural corresponding images of other patterns among the plural images obtained at the imaging step in the first area to produce plural difference images each representing a difference between the image of the pattern in the first area and a respective one of the plural corresponding images of the other patterns; detecting a defect candidate image of the pattern in the first area by selecting, among the plural difference images produced at the step of comparing an image of a pattern in the first area, a difference image having a minimum difference other than zero, and extracting a first feature quantity of the selected difference image selected as the detected defect candidate image; imaging a second area of the chip and corresponding areas of the other plural chips to obtain plural images of corresponding patterns; comparing an image of a pattern in the second area of the chip with plural images of patterns in the corresponding areas of the other chips to produce plural difference images each representing a difference between the image of the pattern in the second area of the chip and a respective one of the plural images of patterns in the corresponding areas of the other chips; detecting a defect candidate image of the pattern in the second area by selecting, among the plural difference images produced at the step of comparing an image of a pattern in the second area, a difference image having a minimum difference other than zero, and extracting a second feature quantity of the selected difference image selected as the detected defect candidate image; extracting a true defect among the defect candidates in the first area and the second area by using said first and second extracted feature quantities; and outputting information of the true defect to a display for displaying information of the true defect.