Tert‐Butyl–Engineered Trinuclear Tin Complexes for High‐Sensitivity Sub‐10 Nm Patterning

ABSTRACT As nano‐devices approach sub‐10 nm resolution, photoresists face increasing demands for both superior pattern fidelity and high sensitivity. However, achieving an optimal balance between high resolution and sensitivity remains a major challenge for existing photoresist systems. In this study, we report a novel class of trinuclear tin‐based molecular photoresists that exhibit stable imaging performance in electron beam lithography (EBL) and extreme ultraviolet lithography (EUVL), as well as excellent plasma etch resistance. Notably, tert‐butyl‐substituted trinuclear tin complexes are developed for the first time. These materials achieve high sensitivity (D 0 as low as 33 µC/cm 2 ) and high‐resolution patterning (linewidth down to 10 nm) under EBL. In EUVL, well‐defined 30 nm lines are obtained at a dose of 25 mJ/cm 2 , highlighting the potential of tert‐butyl substitution in the design of high‐performance photoresist. Density functional theory calculations indicate that tert‐butyl substitution elevates the highest occupied molecular orbital energy level and reduces the vertical ionization potential, facilitating photoelectron generation. Mechanistic studies further reveal that high‐energy irradiation induces the formation of relatively stable tert‐butyl radicals, which promote Sn‐alkylene‐Sn cross‐linking networks. This synergistic effect significantly enhances patterning performance. Overall, this work deepens the structure–property understanding of metal‐based photoresists and guides the design of high‐sensitivity materials.