| 摘要 |
PROBLEM TO BE SOLVED: To enhance the reliability of an inspection and to make detectable a fine pattern defect in a pattern inspection in which images are compared so that their disagreement is regarded as a defect. SOLUTION: Image patterns of chips 2a, 2b which are read out by a linear image sensor 5 are aligned by a delay memory 7 and an alignment circuit 12, they are compared by a defect judgment circuit 13, and a defect is detected. Density information on the image patterns is detected by a binarization circuit 9a so as to be stored in a state storage circuit 14. The shift amount and the number of disagreement pixels with respect to it are detected respectively on the basis of edge patterns of the binarization circuit 9a and a binarization circuit 9b so as to be stored in the state storage circuit 14. An alignment/ sensitivity control circuit 12 detects a defect by controlling the alignment circuit 12 according to not only a recent shift amount but also a previous shift amount or a determined shift amount or by changing a defect detecting sensitivity when the shift amount and the number of disagreement pixels of the disagreement detection circuit 10 in a previous inspection are different.
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