High-Aspect-Ratio Nanometer-Pattern Fabrication Using Fullerene-Incorporated Nanocomposite Resists for Dry-Etching Application

This paper presents the improved performance of a nanocomposite resist system that incorporates an unseparated mixture of fullerenes C 60 and C 70 into ZEP520, a positive electron-beam resist, particularly focusing on the enhancement of mechanical strength and dry-etching resistance. This system exhibits similar improvements to that of a pure C 60 -incorporated system; 90-nm-pitch high-aspect-ratio (>5) resist patterns without pattern collapse and a 10-% enhancement of dry-etching resistance are obtained in a 10-wt% fullerene mixture-incorporated system due to the reinforcement effect induced by the fullerene incorporation. In addition, 80-nm-pitch resist patterns are successfully transferred to SiN film by C 2 F 6 -reactive ion etching without any harmful effects. The use of an unseparated mixture of C 60 and C 70 , which is commercially available at a much lower price than pure C 60 , will greatly facilitate the practical application of the nanocomposite resist system from the economic point of view.