DEVICE AND METHOD FOR VISUAL INSPECTING AND STORAGE MEDIUM STORING VISUAL INSPECTION PROGRAM

Japanese Patent JP3120767

B2

PROBLEM TO BE SOLVED: To enable visual inspection without increasing the necessary amount of calculation and storage capacity even with heightening accuracy in positioning while preventing the occurrence of pseudo defects.
SOLUTION: A device for visual inspection comprises an image differential part 2 of the inspection image and reference image of an object to be inspected, an image dividing part 3 to divide images, a pixel accuracy positioning part 4 to superimpose the inspection image on the reference image, a function fitting part 5 to fit a unimodal function to the density-variable value distribution of the absolute values of pixel values in a direction intersecting an edge at right angles, a computing part 6 of misregistration in sub-pixel accuracy, a modified differential image creating part 7 to create a modified differential image by rewriting pixel values so that the density- variable distribution of pixel values may follow the form of a unimodal function on a direction intersecting an edge at right angles on corresponding two edges, and an image comparing part 8 to compare the modified and divided differential image of the inspection image with the modified and divided differential image of the reference image on the basis of misregistration in sub-pixel accuracy to detect defects in the object to be inspected.

Hisashi Shiba

JP655298A

December 25, 2000

January 16, 1998

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NEC

G01B11/24; G01N21/88; G01N21/956; G03F7/20; G06T7/00; H01L21/66; (IPC1-7): G01N21/956; G01B11/24; H01L21/66

JP4194702A

Akihiko Nakazawa

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