Electron-Beam Resist Edge Profile Simulation

Resist edge profiles of lines produced by electron-bean] exposure are explored through the use of numerical simulation. The modeling approach uses Monte Carlo simulation of electron catteiing and energy dissipation, a simple etch rate versus dose model for the resist, and a string development algorithm. The simulation was made on an IBM 370/158 and primarily considers a multiple-spot Gaustian beam exposure of PMMA resist. An absolute quantitative einduation of the simulation accuracy is made based on resist exposure-develop-ment measurements and comparisons with SEM micrographs of experimental profiles. The comparisons show good quantitative agreem and indicate that modeling can be used as a quantitative p.rocessing aid. Simulation results illustrate the importance of resist, beam, and substrate parameters in the context of optical mask writing (0.5-/on resist on 0.08-jum Cr on Si02) and direct wafer writing (1.0-|Ltm rerist on Si, Gd3Ga5Oi2, and Au). Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.