| 摘要 |
PURPOSE:To detect a defect with high accuracy, even when an inter-layer misalignment between 2 patters subjected to comparison and microscopic undulations are observed, by specifying an significant disagreement of a specimen for inspection as a probable defect and comparing a plurality of image elements inside a window. CONSTITUTION:Outputs of linear image sensors 5a, 5b are subjected to positioning by a position-deviation correcting circuit 22. Signals 19, 20 without the position-deviation are transmitted next to a differential image detecting circuit 23 for detection of absolute values of difference of the signals 19, 20. Next, the differential image is binarized by a binarization circuit 24 and any probable detects are detected. From the probable defects those including less than 3 image elements are removed by a 3X3 window processing circuit. Output of the window processing circuit 25 has larger disagreement amounts of signals 19, 20 and produces a size of 3 image elements and up. Next, an inside-gradients of signals 19, 20 are obtained concerning these probable defects by gradient detecting circuits 26, 27. The gradients thus obtained are compared one with the other by a comparing circuit 28 and if difference turns-out is pronounced, then it is determined as a defect. |
