摘要 |
A method is disclosed in which a plurality of variable shaped beam (VSB) shots is used to form a desired pattern on a surface. Shots within the plurality of shots are allowed to overlap each other. Dosages of the shots may also be allowed to vary. 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. The method of the present disclosure may be used, for example, in the process of manufacturing an integrated circuit by optical lithography using a reticle, or in the process of manufacturing an integrated circuit using direct write.
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