A Monte Carlo simulation of electron beam lithography used to create 0.5micron structures on GaAs.

We have used a positive trilevel resist structure on GaAs to verify our general purpose calculations of electron beam lithography. The model uses a single-scattering Monte Carlo simulation of electron-solid interactions, a simple dissolution rate versus energy model for the resist and a string model for resist development. The spot size of the electron beam was varied from 0.2 to 0. 4micron in diameter. Experimental results on SEM line widths and wall profiles are in good agreement with the simulation. Using the model, we have determined the change in process latitude with increasing spot size. However, we find that the lithography process will still be able to create 0.5micron lines even with large (0.4micron) spots.