Enhanced Resolution of Poly-(Methyl Methacrylate) Electron Resist by Thermal Processing

TL;DR

This paper introduces a thermal processing method that significantly improves the resolution and surface quality of poly(methyl methacrylate) electron resist, enabling patterning of features smaller than 5nm.

Contribution

A novel thermal process combined with optimized development conditions for PMMA resist, achieving higher resolution and smoother surfaces in electron beam lithography.

Findings

Patterned holes smaller than 5nm in diameter.

Reduced line edge roughness to 1nm.

Reduced surface roughness to 100pm.

Abstract

Granular nanostructure of electron beam resist had limited the ultimate resolution of electron beam lithography. We report a thermal process to achieve a uniform and homogeneous amorphous thin film of poly methyl methacrylate electron resist. This thermal process consists of a short time-high temperature backing process in addition to precisely optimized development process conditions. Using this novel process, we patterned arrays of holes in a metal film with diameter smaller than 5nm. In addition, line edge roughness and surface roughness of the resist reduced to 1nm and 100pm respectively.