Chapter 17 - Scanning helium ion beam lithography

Abstract

Advances in gas field ion source technology over the last decade have led to renewed interest in ion beam lithography as an alternative to the widely used electron beam lithography technique. At the forefront of this resurgence is helium ion beam lithography (HIBL), in which a subnanometer focused beam of helium ions is used to define high-resolution (sub-10-nm scale) patterns in resist. This chapter firstly describes the helium ion beam system, before presenting a comprehensive study on the unique properties of ion–solid interactions that potentially make helium ions more favorable than electrons in lithographic applications. Examples of HIBL applied to various resists, both polymeric and molecular, are then discussed with a focus on sensitivity, proximity effect, and minimum feature size of high-density patterns. Potential applications of HIBL are reviewed, including rapid prototyping of nanodevices, production of nanoimprint templates, and prescreening of extreme ultraviolet resists.