| 摘要 |
PURPOSE: To enable the reference point of a projection optical system to correspond accurately (base line measurement) to the reference point of a through-the- lens alignment system by a method wherein the effect of a reticle pattern drawing error is lessened in a slit scan method. CONSTITUTION: Two rows alignment mark images 29AW to 29DW and 30AW to are projected onto a projection image 12W of a reticle in a scanning direction, and first reference marks 35A to 35D and 36A to 36D and second reference marks 37A to 37D are formed also on a reference plate 6 in the direction of scanning. The reticle and the reference mark plate 6 are moved in a scanning direction, the positional deviation of the mark images 29AW and 30AW from the reference marks 35A and 36A are obtained, and the positional deviation of other mark images from the reference marks are also obtained the same as above, a base line is measured basing on the average value of these deviations and the positional deviation of a second reference mark observed by a TTL wafer alignment system. |
