| 摘要 |
A method for fracturing or mask data preparation or proximity effect correction of a desired pattern to be formed on a reticle is disclosed in which a plurality of variable shaped beam (VSB) shots are determined which can form the desired pattern. Shots within the plurality of VSB shots are allowed to overlap each other. Dosages of the shots may also be allowed to vary with respect to each other. The union of the plurality of shots may deviate from the desired pattern. The plurality of shots may be determined such that a pattern on the surface calculated from the plurality of shots is within a predetermined tolerance of the desired pattern. In some embodiments, an optimization technique may be used to minimize shot count. In other embodiments, the plurality of shots may be optionally selected from one or more pre-computed VSB shots or groups of VSB shots.
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