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 C2F6-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.