| 摘要 |
PURPOSE:To easily measure a gap between a photomask and a wafer with high accuracy by image-forming a reticle measurement pattern on the photomask and the wafer respectively and detecting the extent of movement at that time to measure the gap between both. CONSTITUTION:The photomask 1 and the wafer 2 are arranged at the regular exposure positions. a stage 15, an objective lens 6, etc., are then moved along a guide member 16 and an image 18 of the measurement pattern 12 of a reticle 11 on the mask 1 is observed by a TV camera 8 and formed by using an auto- focusing device 9 of imaging processing, etc. The stage 15, the objective lens 6, etc., are moved along the guide member 16 and an image 19 of the measurement pattern 12 of the reticle 11 on the wafer 2 is formed in the same way as done with respect to the mask 1. In these cases, the gap between the mask 1 and the wafer 2 can be measured with high accuracy by detecting the extent of movement of the stage 15 by a sensor 17. |
