| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for exposure which is capable of suppressing a contrast depreciation and a deterioration in depth of focus, when making use of FLEX method (multiple imaging exposure) and maximizing the capability of the FLEX method. SOLUTION: This method of exposure comprises the transfer of the same pattern at a plural number of focal planes, by making use of a Levenson-type phase shift mask 31 and an exposure of a wanted pattern on a wafer 34 by superposing a projected image on a plural number of foal planes. Based on the phase error and the pattern size of a phase shifter of the mask 31, the space for each focus plane having a maximum depth of focus against the exposure tolerance required is obtained, and the focal plans are set depending on the space. |
