Monte Carlo simulation of electron beam lithography on topographical substrates
A Monte Carlo program suite MOCASEL has been developed for 3-D simulation of e-beam lithography over a flat or a topographical substrate. A new "electron cloud" scheme is introduced to reduce the number of electrons used in the simulation, which results in a considerable reduction of computation time. Electron trajectories over substrate topography of single or composite materials are presented. 3-D resist profiles on a flat substrate and on a topographical substrate are compared. The line "swelling" effect due to electron forward scattering from a topography is revealed.