Hybrid electron beam and optical lithography method

Abstract

A complete lithographic exposure pattern is formed in accordance with this invention by forming part of the complete pattern with electron beam radiation and forming the remaining part with light radiation. The electron beam exposure pattern part delineates all of the edges of the desired complete pattern while the optical exposure pattern part fills in any remaining regions, together forming the desired complete exposure pattern. Since all edges are delineated by electron beam radiation, any radiation sensitive layer exposed to the complete pattern will develop edges characteristic of an electron beam pattern exposure. Electron beam exposure system thruput is improved because the whole pattern is not exposed by electron beam. Preferably, the exposure width of the electron beam edge delineation is on the order of the minimum linewidth of the pattern, so that proximity effects will be automatically reduced or eliminated without requiring computation of the exposure contribution from adjacent shapes in the pattern due to lateral scattering effects and without requiring any variation in the applied electron beam exposure dose. Use of a wider exposure width for electron beam delineation of pattern edges has the advantage that alignment tolerance of the optical exposure pattern part with respect to the electron beam exposure pattern part is increased.