Automatic determination of spatial dose distribution for improving accuracy in e-beam proximity effect correction

Proximity effect correction in E-beam lithography is expected to be an essential step in fabrication of high-density fine-feature circuits in the future. In the past, we demonstrated successful proximity correction by a shape modification approach with a single dose for the entire circuit pattern. This approach has a few advantages over dose modification, including the fact that it is "compatible" with future multiple-beam or projection-based systems. As we continue to reduce the minimum feature size, accuracy of correction becomes more critical. In order to improve correction accuracy of the shape-only modification, a hybrid approach allowing region-wise dose control was proposed previously. In this paper, a practical fast scheme for determining spatial dose distribution is presented.