Enhancing the PMMA Photoresist Film via Ozone Treatment and Vapor Phase Infiltration

Achieving photoresists that combine low film thickness and high etch resistance while maintaining high resolution presents a challenging contradiction. Doping a poly(methyl methacrylate) (PMMA) film with metal oxide was demonstrated to provide better etch performance, but the line roughness was significantly scarified. Herein, we report an efficient PMMA surface treatment followed by vapor phase infiltration (VPI) for greatly improved deposition of hafnium oxide (HfO x ). By treating PMMA with ozone and infiltrating it with tetrakis(dimethylamino)hafnium (TDMAH), a hybrid photoresist achieving 30 nm half-pitch (HP) resolution under extreme ultraviolet lithography (EUVL) (74 mJ/cm 2 ) with enhanced etch resistance (>120% improvement) and reduced line edge roughness (LER < 10 nm) was realized. This approach provides a viable solution for next-generation lithography by enabling thinner resists without compromising plasma etch resistance, which is critical for advanced semiconductor manufacturing.