Radical sensitive Zinc-based nanoparticle EUV photoresists

Zirconium- and hafnium-based nanoparticles demonstrated good patterning behavior in deep-ultra-violet (DUV), electron-beam (E-beam) and extreme ultra-violet (EUV) lithography. Among these Zr- and Hf-based hybrid nanoparticles, the methacrylic acid (MAA) modified zirconium oxide nanoparticles¹ (ZrO₂-MAA-NP) give out the best over-all-performance: 26 nm lines are obtained at 4.2 mJ/cm². However, both Zr and Hf are relatively low EUV absorbing metals², and integration of high EUV absorption elements, such as Zn, is considered to be a more promising route to further improve lithographic performance under EUV radiation. Zinc-based nanoparticle photoresists, possessing ultra-small size, have exhibited promising sensitivities and better resolution. Here, we combined methacrylate ligand and high EUV absorption element Zn, to demonstrate a novel zinc oxide-based nanoparticle photoresist using a photo-radical generator (PRG). Compared with conventional photo-acid initiated nanoparticle-based photoresists, a better resolution and sensitivity has been found with the addition of photo-radical generator (PRG). This unique behavior is promising to provide new possibilities for rapid three-dimensional (3D) -printing.