Fullerene-derivative nanocomposite resist for nanometer pattern fabrication

A nanocomposite resist system that incorporates a fullerene derivative into a conventional positive-type electron-beam resist, ZEP520, is examined. Because of the enhanced solubility of the derivative, the system exhibits a minimal decrease of sensitivity even at an incorporation content of 50 wt% and enables the fabrication of 50 nm patterns with a line dose of 0.39 nC/cm. At higher contents, however, the derivative is not as effective as fullerene C-60 or C-70 in improving dry-etching resistance because of the aggregation of the derivative molecules, which is probably due to the uniqueness of the derivative used and will be avoided by appropriate molecular design.