Proximity effect correction for large patterns in electron-beam projection lithography

In electron-beam projection lithography (EPL), a variety of patterns is exposed at once and dose modification method can not be used for proximity effect correction. Pattern shape modification method is a strong candidate. It requires a special technique for large patterns since the back scattering energy can not be reduced by simple sizing. We have proposed a correction algorithm employing both shape modification and interior area removal method in which pattern densities at the middle parts of large patterns are reduced by utilizing lines and spaces patterns (L/S) or mesh patterns. In the process of interior area removal, a concrete method of pattern generation of L/S or mesh has not been proposed. In this paper, the authors discuss which patterns, L/S or mesh, should be used and how to determine the widths of line and space of these patterns.