| 摘要 |
PURPOSE:To improve the positioning precision between a mask and a wafer by arranging a position detector on an optical path, where the optical signal from a matching mark is detected, to detect the extent of deviation of an optical element on the optical axis. CONSTITUTION:A photoelectric detector 19 has two light receiving faces 29 and 30 in the center part and has a circular light receiving face 28 in the peripheral part. If a mirror 5 is placed in a regular position, a light (h) reflected directly on a wafer 2 passes an aperture 20a and is made incident on two light receiving faces 29 and 30 equally. A mask 1 and the wafer 2 are positioned after positioning of the mirror 5 is terminated, and a matching mark M consisting of downward opening bar-shaped patterns 21-24 is formed on the wafer 2, and a matching mark M' consisting of similar patterns 25 and 26 is formed on the mask 2. Marks M and M' are scanned along a scan axis C by a laser beam to move a moving stage 12, thus matching the mask 1 and the wafer 2. |
