Molecular Dynamics Simulation of Pattern Formation for Negative-Type Resists in Electron Beam Lithography

We have developed a molecular dynamics simulation that reproduces the pattern formation process of electron beam lithography for negative-type resists. Structural change of resist material by electron beam exposure was introduced as crosslinking between resist molecules. The crosslinks were formed at each position of the resist in proportion to the absorbed energy distribution obtained by the Monte Carlo simulation of electron scattering according to the electron exposure conditions. Development was reproduced by removing the low molecular weight resist molecules from the system. The pattern size obtained after development showed shrinkage due to the cohesive force acting between molecules. It was also shown that the undulations seen at the pattern edge are suppressed by the cohesive force and the pattern roughness is reduced.