Incorporating iodine into polypeptoid chemically-amplified resists for improved EUV sensitivity

As extreme ultraviolet lithography advances towards patterning smaller features, stochastics and sensitivity are two challenges that polymeric photoresists must overcome. Traditionally, synthetic limitations cause chain-to-chain variations in polymer molecular weight, composition, and sequence which are compounded by material stochastics in resist formulations. Together with poor EUV absorption by polymeric materials, this contributes to unacceptable levels of line-edge roughness and other patterning defects. Polypeptoids are a unique class of bio-inspired polymers that can be synthesized with a perfectly defined sequence, composition, and molecular weight, yielding a uniform material. In this study, we have incorporated metals and halogens into polypeptoid-based chemically amplified resists to investigate the impact of strongly EUV-absorbing elements on the sensitivity of polymeric photoresists. These polypeptoid CARs have been evaluated under DUV and electron-beam lithography.