Suppressing of secondary electron diffusion for high-precision nanofabrication

Nanopatterning is a well-established approach to fabricating nanostructures in electronics and optics, and exploiting patterning strategy to achieve smaller feature sizes and higher precision is urgently and constantly pursued. State-of-the-art extreme ultraviolet lithography and electron beam lithography have proven to produce smaller sizes. However, for such energetic radiation-based approaches, the serious diffusion behavior of the radiolytic low-energy secondary electrons will result in unpredictable defects in the unexposed matrix, limiting the ultimate resolution and hindering its potential in sub-10 nm patterning. Herein, we report significant progress in high-resolution patterning via suppressing of residues caused by secondary electron diffusion, and 10 nm line-space nanostructures are achieved by utilizing a free radical quencher in patterning a highly sensitive zirconium-containing photoresist. Lithography evaluation combined with theoretical calculation reveals this novel radical quencher approach can effectively suppress undesired electronic excitation and ionization reactions, thereby significantly improving resolution and edge roughness. By inhibiting secondary electron-induced active species, this quenching mechanism is found to increase the onset dose and effectively narrow the energy deposition; thus improving the patterning contrast and facilitating the acquisition of straight lines with sharp edges. This work provides a new perspective on active species diffusion control for higher precision nanoscale fabrication.