Fully dry-processed positive-tone electron beam lithography using myo-inositol

The development of fully vacuum-compatible lithographic processes presents an avenue for enhancing throughput in microfabrication and avoiding the limitations imposed by wet-chemical processing. While novel negative-tone, all-vacuum processes have emerged, a positive-tone equivalent has remained elusive. This article describes early assessments of myo-inositol as a fully dry-processed, positive-tone electron-beam-sensitive film. The film is deposited via thermal vapor deposition, exposed with an electron beam at 3.6 nC/cm, and developed by heating the substrate in vacuum at 125 °C. This process preferentially removes the exposed material, and we demonstrate the fabrication of 50 nm lines at 200 nm pitch. While limited in etch resistance, this work contributes a stepping stone toward positive-tone, fully dry, vacuum cluster tool fabrication.