Acid-breakable Resin-based Resist for Nanofabrication Electron-beam Lithography

A new chemical amplification positive resist system designed for nanofabrication electron-beam lithography is described. The positive resist system consists of an acid-generator and an acid-breakable (AB) resin that can be converted to polyphenol fragments by an acid-catalyzed reaction. The AB resin is synthesized through a co-condensation reaction between polyphenol and aromatic multi-functional vinylether compounds (bisvinylether and trisvinylether compounds). Molecular weight (MW) of the AB resin increases with an increase in the vinylether feed ratio. A condensation reaction with a polyphenol/vinylether feed ratio of 100/50 results in a high MW (Mw>5000) AB resin which is insoluble in an alkali developer (tetramethylammonium hydroxide: 2.38wt%). The acid-catalyzed fragmentation of the AB resin in the resist film was confirmed through gel permeation chromatography. The resist with the AB resin showed the high resolution of 80-nm line-and-space patterns with high sensitivity (5.0μC/cm2 at 30kV).