METHOD AND APPARATUS FOR INSPECTING DEFECT OF CIRCUIT PATTERN

摘要

PURPOSE:To accurately detect the breakage of the bottom part of a pattern by extracting an area where a circuit pattern must be present using an image processing means with respect to the photographed image of the circuit pattern and judging the defect only of the extracted area. CONSTITUTION:A printed wiring board 2 is irradiated with X-rays and the transmitted X-rays from the board 2 are applied to an X-ray fluorescent multiplier tube 3 to convert an X-ray image into an optical image. The optical image is formed from the dark part 14, dark part 15 and bright part 16 respectively corresponding to a part where a circuit pattern is present on a single surface, a part where the circuit pattern is present on both surfaces and a pattern absent part. The optical image is photographed by an imaging tube 4 to obtain an image. A circuit pattern extracting logical circuit 5 separates the image into the areas 17, 18 respectively corresponding to the part where the pattern must be present and the pattern absent part to extract the area 17 as an object to be inspected. A defect inspecting logical circuit 6 compares the signal intensity of the image with a present defect inspection reference value to inspect a defect. Defect data is outputted to an inspection result output part 7 to detect the abnormality in the thickness direction of the pattern.