IMPROVED ELECTRON-BEAM PATTERN WRITING IN SIO2 WITH THE USE OF A SAMPLE HEATING STAGE

In previous electron beam direct-write SiO2 experiments [D. R. Allee a nd A. N. Broers, Appl. Phys. Lett. 57, 2271 (1990); D. R. Allee, C. P. Umbach, and A. N. Broers, J. Vac. Sci. Technol. B 9, 2838 (1991)], co ntamination has always been formed during exposure as a result of the high electron dose required by the SiO2 process. Not only does this co ntamination need to be removed prior to development of the patterns in SiO2, but it also causes additional electron beam scattering and can therefore be a factor limiting the resolution of the SiO2 process. In this letter, we report improved pattern writing in SiO2 through the us e of a sample heating stage. The SiO2 sample is heated in situ at appr oximately 200-degrees-C during exposure. This eliminates the formation of contamination and, as a result, decontamination is not needed and the exposed oxide can be developed immediately after exposure. Using t his writing process, trenches on 10.8 nm periods have been demonstrate d in SiO2.