Improved Lithographic Performance for EUV Resists Based on Polymers having a Photoacid Generator (PAG) in the Backbone

Abstract

Polymer bound PAG resists, poly(4-hydroxystyrene-co-2-ethyl-2-adamantyl methacrylate-co-PAG1) [poly(HOST-co-EAMA-co-PAG1)] and poly(4-hydroxystyrene-co-2-ethyl-2-adamantyl methacrylate-co-PAG2) [poly(HOST-co-EAMA-co-PAG2)] have been synthesized and evaluated as potential components of EUV resist materials with enhanced lithographic properties such as photospeed and Line Edge Roughness (LER). The polymer bound PAG resist exhibited faster photospeed and lower LER than the corresponding blend of photoacid generator (PAG) and copolymer resists, poly(HOST-co-EAMA) with blend PAG3 (Triflate) and poly(HOST-co-EAMA) blend with PAG4 (Nonaflate). These results imply that this novel resist system has potential advantages over conventional resists and should be further explored for application in EUV lithography. Furthermore, use of different counter anions such as triflate and nonaflate influenced the lithographic performance. Sub-100 nm features were obtained with improved lithographic performance such as photospeed and LER using EUV exposure.