| 摘要 |
PURPOSE:To easily and precisely execute inspection by a method wherein image elements by reference microscopes for reference mask and inspected mask are stored as binary information and the positional deviation between a picture signal and a reference signal is obtained. CONSTITUTION:A reference mask 9 and an inspected mask 10 are respectively irradiated by light sources 31, 32 and imagery of patterns are performed by objective lenses 34, 35. Reference and inspected mask pattern images are analysed into two dimensional array picture elements by image elements 36, 37 and are stored in picture signal registers 38, 39 as picture signals which are the binary information of individual light and shade picture elements. Meanwhile, a binary reference signal is generated from a pattern signal generator 40 and is stored in a reference signal register 41. The contents of the picture signal registers 38, 39 and the reference signal register 41 are operated and compared to measure the positional deviation value of the superposition accuracy inspection pattern of the reference mask and inspected mask from an arbitrary reference point. |
