Sub-20nm lithography negative tone chemically amplified resists using cross-linker additives

Here, we report the highest recorded resolution for a negative-tone, carbon-based, chemically amplified (CA) resist of 20 nm half-pitch (HP) using both E-beam and EUV exposure systems. The new chemistry incorporates variable amounts of oxetane (0, 5, 10 and 20%) cross-linker into a base of Noria-MAd (methyl-admantane) molecular resist. Cross-linkable resists showed simultaneous improvements in surface energy, structural integrity, and swelling to ensure collapse free 20nm HP patterns and line-edge roughness (LER) down to 2.3 nm. EUV exposed Noria-Ox (5%) cross-linked resist patterns demonstrated 5 times improvement in Z-factor (for 24 nm HP) over Noria-MAd alone.