Synthesis and Characterizations of a Nonalkyl Tin Oxo Cluster and its Application as High EUV Absorption Coefficient and Etch Resistant Inorganic Resist for EUV Lithography.

We introduce a novel nonalkyl tin oxo cluster, CNU-TOC-01(4C-C), synthesized through a reflux-based solution reaction using SnCl, HO, and pyrazole, which permits scalable production and molecular customization. Using field desorption-time-of-flight mass spectrometry (FD-TOF MS) and small-angle X-ray scattering (SAXS), CNU-TOC-01(4C-C) is characterized as a cyclic cluster with the molecular formula SnCl(CNH)(CNH)HO. The cluster size was measured to be 11.6 Å by SAXS and estimated to be 11.1 Å lengthwise in quantum chemical calculation. The synthesized material exhibits an extreme ultraviolet (EUV) linear absorption coefficient of 20.7 μm. Initial application in EUVL and electron beam lithography (EBL) achieved fine line and space patterns with the potential for ultrafine resolutions upon optimization. CNU-TOC-01(4C-C)'s high etch resistance underscores its exceptional suitability as an advanced resist material for future lithographic applications.