New Generation Electron Beam Resists: A Review

Abstract

The semiconductor industry has already entered the sub-10 nm region, which has led to the development of cutting-edge fabrication tools. However, there are other factors that hinder the best outcome of these tools, such as the substrate and resist materials, pre- and postfabrication processes, etc. Among the lithography techniques, electron beam lithography (EBL) is the prime choice when a job requires dimensions lower than 10-20 nm, since it can easily achieve such critical dimensions in reasonable time and effort. When obtaining pattern features in single nanometer regime, the resist material properties play an important role in determining the size. With this agenda in mind, many resists have been developed over the years suitable for attaining required resolution in lesser EBL writing time. This review article addresses the recent advancements made in EBL resists technology. It first describes the different lithography processes briefly and then progresses on to the parameters affecting the EBL fabrications processes. EBL resists are then bifurcated into their "family types" depending on their chemical composition. Each family describes one or two examples of the new resists, and their chemical formulation, contrast-sensitivity values, and highest resolution are described. The review finally gives an account of various alternate next-generation lithography techniques, promising dimensions in the nanometer range.