| 摘要 |
PURPOSE:To increase the speed of scanning in scanning sections corresponding to inspection unnecessary regions after succeeding scannings by deciding the mutual unequal picture regions of each period in a picture obtained by an initial scanning as the inspection unnecessary regions. CONSTITUTION:When an XY table 4 is moved regularly by a drive 5, an image pickup device 7 relatively scans a wafer 1, and generates a picture signal. The wafer is mounted at fixed speed regarding a scan in a first scanning line L1 for the first time in the picture take-in scanning. The wafer is mounted at high speed in inspection unnecessary sections corresponding to non-cell regions by operation mentioned below regarding scannings in subsequent lines L2, L3.... The picture signal from the image pickup device 7 is applied directly to one input terminal of a differential signal generator 10 while being applied to a delay circuit 9. In the delay circuit 9, the picture signal is delayed only by one period S section of an inspection object pattern such as one period S section of a cell 3, and the delay signal is applied to the other input terminal of the differential signal generator 10. |
