| 摘要 |
A method, equipment, and a recording medium of controlling exposure accuracy enabling position accuracy to be around ±15 nm by double exposures under different optical conditions. The first exposure is carried out under an optical condition A1 suitable for dense patterns, that is 30-40% the total quantity of light. This optical condition A1 can be optimized by change in the pattern size and the photoresist. After cleaning for restoring the elongation of the wafer and changing the illuminating optical system, the second exposure is carried out under an optical condition B1 suitable for sparse patterns, that is 70-60% the total quantity of light. By this the positioning error of the reticle scan stage, which is a cause of misalignment, is eliminated, and in addition, error caused by the expansion/contraction of the wafer due to cleaning can also be eliminated. As a result, resolution can be improved without lowering the throughput.
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