| 摘要 |
PROBLEM TO BE SOLVED: To improve the accuracy of overlay exposure with multiple times of exposure. SOLUTION: A first pattern and marks 2 for position detection are formed by an exposure such as light exposure and an intermediate treatment such as etching. A wafer is partitioned into correction fields 3 corresponding to the marks 2 for position detection. The position of the mark 2 at each correction field 3 is detected and distortion is found. The position of exposure is determined by correcting the distortion, and a second pattern is exposed to light with an electron beam. The distortion produced during the previous exposure and intermediate treatment is found in advance. The marks 2 are distributed densely in the parts where the distortion is large and the area of the correction field 3 is small. Accordingly, as distortion in a part is larger, correction in each correction field can be made in detail. On the other hand, in a part where distortion is small, workability in high because there are a few correction fields in a large area. |
