Anionic Photoacid Generator Bound Polymer Photoresists With Improved Performance for Advanced Lithography Patterning

Abstract

Chemically amplified resist (CAR) has gained considerable attention in the realm of extreme ultraviolet lithography (EUVL) due to their exceptional photosensitivity, high resolution, and commercialization. This work presents the development of an anionic photoacid generator (PAG) bound polymer (PGM) photoresist composed of three rationally selected monomeric units: 2‐Phenyl‐2‐propyl methacrylate (PPMA), γ‐butyrolactone‐3‐yl methacrylate (GBLMA), and triphenyl sulfonium salt 1,1,2‐trifluorobutanesulfonate methacrylate (MTFBS‐TPS). Electron beam lithography (EBL) studies demonstrate that the PGM photoresist functions as a positive tone photoresist with commendable sensitivity (27.9 μC/cm2) and contrast (6.53). When compared under similar conditions, with equal amounts of PAG and identical processing, the PGM photoresist exhibited superior pattern fidelity, ease of handling, and higher line resolution (25 nm) relative to the triphenyl sulfonium triflate (TPS‐OTF) blend polymer (PG‐T) photoresist. This enhancement is probably caused by anionic PAG directly attaching to the polymer backbone, which mitigates acid diffusion during the post‐exposure baking (PEB) process. Moreover, the PGM photoresist obtained a pattern of 37.5 nm at 50 mJ/cm2 in the EUVL test. The positive tone resists were successfully applied for the fabrication of nanoscale patterns.