EUV metal oxide hybrid photoresists: ultra-small structures for high-resolution patterning

Extreme ultraviolet (EUV) lithography, using 13.5 nm radiation, is considered one of the most prominent candidates for next generation lithography. The main challenge for EUV resists is to simultaneously satisfy resolution, LWR (line-width roughness) and sensitivity requirements according to the ITRS roadmap¹. Over the past few years, our main effort has been to focus on ZrO₂ and HfO₂ nanoparticle-based photoresists. However, both Zr and Hf are relatively low EUV absorbing metals², and integration of high EUV absorption elements is considered to be a more promising route to further improve lithographic performance under EUV radiation. Here, we demonstrate novel zinc oxide-based nanoparticle photoresists, possessing small particle size, good solubility in spin-coating solvents, good film-forming abilitie and patterning by incorporating a photo-acid generator or photo-radical generator.