An aluminum-based hybrid film photoresist for advanced lithography by molecular layer deposition†

In the realm of advanced integrated circuits, the demand for novel resist materials becomes paramount as we progress toward smaller process nodes. Inorganic photoresists have received widespread attention due to their higher absorption of extreme ultraviolet (EUV) light and higher etch resistance. In our study, we employed trimethylaluminum (TMA) and 2-butene-1,4-diol (BED) via molecular layer deposition (MLD) to deposit an Al-based hybrid film coined “TMA–BED,” serving as an electron-beam photoresist. Through inductively coupled plasma (ICP) etching for resistance testing, the TMA–BED film exhibited exceptional selectivity with Si etching, reaching a minimum of ∼86, surpassing traditional photoresists by 14 times. Sensitivity and resolution were assessed using electron-beam lithography with 10 wt% ammonia as the developer, revealing a sensitivity of 450 μC cm⁻² at 2 keV and the capacity to resolve 10 nm line widths at 50 keV. Our results underscore the tremendous potential of TMA–BED hybrid films, deposited through MLD, for advanced lithographic techniques.