Energy Dissipation by Electron Beam Scattering in Thin Polymer Films.
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
Pagination or Media Count:
Monte Carlo calculations have been performed to determine the spatial distribution of energy dissipated in a 4000-A-thick film of polymethyl methacrylate PMMA, due to an incident electron beam. The calculations were performed for 5-, 10-, and 20-keV electrons on a silicon substrate and also for 20-keV electrons on copper and gold substrates. The effect of varying the beam diameter from 250 to 3000 A is evaluated. A detailed comparison is made between the Monte Carlo results and analytic models used to predict the energy dissipated. The plural-scattering model is found to be in good agreement with the Monte Carlo calculations, whereas discrepancies are found with the multiple-scattering model. The large-angle backscattering model is found to have several important limitations. Energy dissipation is calculated for the exposure of dots, isolated lines, and arrays of closely spaced lines - geometries that are of significance in electron beam lithography.
- Physical Chemistry