Pattern formation in electron beam lithography (EBL) is investigated with molecular dynamics simulations. The electron exposure and development process are modeled by polymer chain scission and polymer segment removal from the resist, respectively. The line edge roughness of a sub-10-nm resist pattern is analyzed with the simulations. The proximity effect in EBL is also investigated. The effects of resist molecular size, secondary electron generation, and the substrate material are discussed.

Multiscale simulations are performed to study the development process in electron beam lithography. The whole pattern profiles are calculated with the cell removal simulation. The pattern profiles are shown to reflect the electron scattering manner in the resist. The local pattern structures are then studied by molecular dynamics simulation. The residual layer with a lot of voids, the residual polymer chains and concave sidewall reflecting the molecular structures are observed as typical atomic-scale pattern structures. The size of the pattern roughness is observed to be comparable with the molecular size of the resist. The diffusion process of the resist molecules among the developer molecules is also analyzed.