Next-generation EUV photoresists-based on chain-unzipping polymers

In this work, we demonstrate the advantages of using chain "unzipping" depolymerization chemistry as Double Amplification Resists (DARs) for Extreme Ultraviolet (EUV) lithography. Unlike conventional Chemically Amplified Resists (CAR), DARs achieve contrast by depolymerizing insoluble polymers into soluble monomers in the presence of a photocatalyst and exposure to activating radiation. Using a previously reported class of polymers known as polyphthalaldehydes (PPAs), we highlight three key variables for DARs: polymer structure, molecular weight, and post-exposure bake temperatures. By applying these design rules, we demonstrate that DARs can achieve faster photospeeds with EUV exposure than a model CAR while maintaining comparable resolution, as evidenced by E-Beam lithography. Finally, we present the first EUV lithography results of contact holes patterned using a PPA-based DAR.