| 摘要 |
PURPOSE:To detect pattern defects by a method wherein mask scanning is applied to all over the binarized image of a repeated pattern in its inspected field and a group of thus obtained image data are subject to periodic law analysis. CONSTITUTION:When two types of patterns B and C are image-processed in the inspected fields with their threshold values being set at 41B DELTA and 41C DELTA, binarized images 61B, 61C are obtained for the patterns B, C, respectively. Pattern defects 52B, 52C are also converted to binary images to remain as indicated by 62B, 62C. Then, a slit-like mask 63 is set on, for example, the binarized image 61B by an image processing unit 34 and, while moving or scanning this mask 63 from the lower end to the upper end of the image, for example, an area of ''1'' level contained in the mask 63 is measured and the resultant data is fed to a computer 35. Such scanning of the mask 63 is performed in a step of TV scan lines so as to obtain changes in the ''1'' level area. When the mask 63 passes the binary image 62B corresponding to the pattern defect 52B or the binarized image 62C corresponding to the pattern defect 52C, the respective changes in the ''1'' level area are disturbed in their periodic law uniformity. The periodic law uniformity is held undisturbed in the remaining scanned area of the mask 63. Thus, the pattern defects 52B, 52C can be detected through period analysis by the computer 35. |
