Self-assembled monolayer resists for electron beam lithography

In this paper, we report the resist characteristics of self-assembled alkanethiol monolayers on gold upon electron beam exposure. We have observed only negative resist behavior for smaller alkanethiols under various exposure conditions. Longer alkanethiols act as either positive or negative resists depending on the exposure conditions. The positive resist behavior is limited by the relative etch resistivity of the unexposed area, which is partly determined by the monolayer quality. We have proposed a dual exposure procedure for improving pattern transferability using both positive and negative resist behavior. The electron induced modifications of self-assembled monolayers are observed to be in qualitative agreement with Bethe´s model for electron-solid interaction.