A comprehensive analysis of low-energy electron exposure on ALD-synthesized inorganic-organic hybrid resist thin films for dry EUV resist platform

This work evaluates various inorganic-organic hybrid resist thin films synthesized using molecular-atomic layer deposition (MALD) for advancing dry EUV resist technology. Different metal ALD precursors, like trimethylaluminum (TMA) and diethylzinc (DEZ), were combined with organic sources such as hydroquinone (HQ) and 4-mercaptophenol (4MP), creating hybrid thin film systems like Al-HQ, Zn-HQ, and Zn-4MP. The ALD growth characteristics and material properties of those systems were thoroughly investigated. All three hybrid thin film systems exhibited negative tone resist characteristics upon electron irradiation. Particularly, Zn-4MP showed the highest sensitivity at 100 eV, requiring the lowest exposure dose to maintain most of its thickness. Zn-4MP demonstrated four times higher sensitivity than Al-HQ but with a lower contrast value. In-situ FTIR and RGA analyses under low energy electron beam exposure revealed similar chemical transformations across the systems, with crosslinking of aromatic rings causing solubility changes.