Electron penetration depths in EUV photoresists

Abstract

One of the obstacles hindering the transition from 193 nm to extreme ultraviolet (EUV) photolithography is photoresist performance. However, design of next generation chemicallyamplified EUV resists necessitates that we fully understand the mechanisms underlying photoacid generation. In particular, we would like to determine the effective distance the lowenergy electrons generated during EUV exposure travel within resists while continuing to induce photoacid generator (PAG) decomposition, since diffusion length carries important implications for resolution and line edge roughness. Here, we demonstrate two novel experimental approaches for obtaining electron diffusion length in resists using top-down electron beam exposure: thickness loss experiments and in situ mass spectrometry.