| 摘要 |
PURPOSE:To test the mask pattern at high speed by high detecting power by testing a minute defect through a single characteristic extracting means and a large defect while being compared with pattern information at the level of geometrical characteristics. CONSTITUTION:The picture signals of the mask pattern are changed into binary, and a picture in a window such as one of a 3X3 picture element is stored by prearranged characteristics (all white, all black, oblique...). A picture element pattern (An isolated point, a thin line, irregularity, etc.) not existing in a normal pattern is decided as the small defect from the geometrical characteristics. On the other hand, pattern information is converted into picture information at every picture element, geometrical characteristics are extracted, both characteristics are compared, and the pattern is decided as the large defect when there is difference. According to the system, the large defect and a defect similar to the mask pattern can also be detected, information in a LN bit can be expressed in a log2N bit when geometrical characteristics are selected in N sorts about the picture element of LXM, and the mask pattern can be tested at high speed with high accuracy. |
