Sub-20-nm-wide metal lines by electron-beam exposure of thin poly(methyl methacrylate) films and liftoff

Abstract

Platinum/palladium lines (17 nm wide) have been defined by the electron‐beam exposure of a film of poly(methyl methacrylate) 60 nm thick supported on a 30‐nm‐thick carbon‐film substrate followed by liftoff of overcoated metal. Line pitch may be reduced to 50 nm before liftoff fails. An 8‐nm‐diam 50‐kV electron beam is used for exposure. A combination of finite source diameter, molecular size effects, and secondary electron exposure are believed to be responsible for the observed resolution limit. It is shown that pattern‐size accuracies of a few nanometers can be achieved.