DEFECT DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To implement a defect inspection by accurately discriminating bubble-caused projection defects and foreign-matter-caused projection defects from surface roughness on a substrate to be inspected.

SOLUTION: A defect detection method includes the steps of: emitting light rays in a direction substantially perpendicular to a substrate to be inspected and receiving the intensity of reflected light generated by the emitted light with an optical sensor; calculating a gradient distribution of pixels from signals detected by the optical sensor and calculating coordinates of a local maximum of gradation; creating a binary image of the pixels from the detected signals, recognizing the shape of a defect candidate and calculating coordinates of the center of gravity of the shape; and identifying the type of the defect by positional relationships between the coordinates of the local maximum and the coordinates of the center of gravity.

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