A dynamic simulation of electron beam induced charging-up of insulators

It is known that insulating materials charge-up negatively or positively depending on its condition during the electron beam (EB) irradiation. This charging disturbs various applications of EB technologies. In the present study a simulation model is proposed to express the charging mechanism of insulators as a function of time under EB irradiation The material studied here is PMMA which is a typical EB resist. In the simulation, the electron deposition distribution is calculated by a Monte Carlo simulation of electron trajectories in the specimen, where the production of secondary electrons and Auger electrons is taken into account. The electron yield obtained by the simulation for non-charged specimen agrees quite well with the experimental result, which has been obtained by using a pulse beam technique.