Polymer sequence alters sensitivity and resolution in chemically-amplified polypeptoid photoresists

Polymer photoresists have long played a critical role in the fabrication of microelectronic devices. However, EUV lithographic patterning occurs on sub-10nm length scales, at which conventional resists struggle with stochastics and sensitivity. Traditional polymers have inherent dispersities in molecular weight, composition, and sequence. These are compounded by material inhomogeneities in photoresist formulations and poor EUV photon absorption, contributing to unacceptable patterning defects. To address these issues, we have developed polypeptoid photoresists to heterogeneity through direct control over polymer sequence and chain length. Sequence specificity of the peptoid system eliminates material dispersities, and a tunable synthesis allows for the incorporation of a vast range of functionalities. In this study, we demonstrate that chain length directly controls dark loss and sequence of monomers (spacing between quenchers and solubility switches) controls pattern contrast and resolution. These findings open up a new design space for polymeric photoresists as we move towards future studies on how the placement of individual functionalities can improve patterning performance.