Comparison of experimental and Monte Carlo results of stochastic Coulomb interaction in projection beam lithography

Coulomb interaction limits the beam current for a required resolution but i t can be influenced by the layout of the optical system. Therefore it is ne cessary to obtain design information for future charged particle lithograph y tools. Monte Carlo simulations are an important tool in this design. Two of these programs, COUTRAC and BOERSCH, are compared with experimental data of an Ion Projection Lithography (IPL) set-up. The results of COUTRAC are in agreement with the measurements to within 19% in case of a uniform cross -over. With an aberrated cross-over the difference increases to 126 % near the axis since the experiment showed no increase of Coulomb interaction ove r the inner quarter of the exposure field while both Monte Carlo models sho w a monotone increase to the axis.