SELF-ASSEMBLED MONOLAYER RESISTS AND NANOSCALE LITHOGRAPHY OF SILICONDIOXIDE THIN-FILMS BY CHEMICALLY ENHANCED VAPOR ETCHING (CEVE)

We report on the use of electron-beam exposed monolayers of undecyleni c acid in the etch rate enhancement of silicon dioxide films in HF vap or for the formation of nanoscale features in the oxide. Variations of the etching characteristics with electron beam parameters are examine d and the results analyzed in terms of proposed models of the etching mechanism. Apparent variations in the relative concentrations of etch initiator with the thermal history of the samples prior to etching pro vides support for the dominant etch initiator within this system as th e carboxylic acid moiety bound at the oxide surface. Other variations in the etching characteristics are discussed in terms of differences i n localized concentrations of hydrocarbon crosslinks and the effect th at this has upon the etch initiation. The process has been employed in the production of features in silicon dioxide surface masks with size s down to 50 nm. (C) 1996 Academic Press Limited