Sequence-defined polypeptoids facilitating stochastics control and EUV patterning study

In EUV lithography, stochastic effects have become more prominent, potentially causing patterning defects. Chemical stochastics are related to the statistical structure of most photoresist molecules, especially polymers, which feature inherent dispersity in molecular weight, composition, and sequence. Additionally, conventional polymeric photoresists often use Photoacid Generators (PAGs), frequently PFAS compounds, which pose environmental and regulatory concerns. This study explores an EUV resist based on polypeptoids, synthesized via the solid phase submonomer method to achieve uniform sequence, length, and composition, while addressing chemical stochastics. The resist is a monomolecular system of sequence-defined, monodispersed polypeptoids incorporating phenol groups (tyramine submonomers), intrinsically patternable under e-beam and EUV exposure. This further reduces stochastic effects from PAG distribution and mitigates PFAS-related concerns. Our polypeptoids pattern via a phenol-based mechanism in a negative tone mode, which has never been applied in EUV resist design before. Lithographic tests on polypeptoids with varying sequences and compositions under EUV exposure were conducted.