Progress in Resists Development for EPL (Electron Beam Projection Lithography)

Electron beam (EB) lithography, together with ArF, F2 and EUV (Extreme Ultra-Violet), is one of the most promising candidates for the next generation 65 nm node and below from the viewpoint of resolution and DOF (depth of focus). However, since EB lithography has a disadvantage in throughput compared with optical lithography, it is generally used for mask and ASIC (Application Specific Integrated Circuits) device manufacturing. The application for it in mass production has been a difficulty. Recently, EPL (Electron Beam Projection Lithography) and LEEPL (Low Energy Electron Proximity Lithography) are being developed to improve the throughput problem of EB. In this paper, we investigated the subject of high sensitivity for imaging resist, which is one of the current topics of EPL. We resulted in an imaging resist which has high sensitivity and small line edge roughness by applying a specific additive and specific resin. Furthermore, we also developed an imaging resist which has high sensitivity and excellent resolution by applying the acid generator which controlled the strength of acid, and diffusion.