Antimony-Oxo-Cluster-Based Polymers as Positive-Tone EBL/EUV Photoresists: Lithography Performance Enhancement by Network Structure Modulation
The development of positive-tone photoresists has emerged as a critical focus in electron beam lithography (EBL) and extreme ultraviolet lithography (EUVL), driven by continuous miniaturization of integrated circuits. Herein, a metal-oxo cluster polymerization strategy is introduced to address the long-standing incompatibility between metal-oxo cluster enhanced EUV absorption and positive-tone lithographic behavior. A binuclear antimony-oxo cluster (SbOC) with polymerizable methacrylate ligands is synthesized and copolymerized with multifunctional thiols (4SH/2SH) via thiol-ene click chemistry, forming crosslinked antimony-oxo cluster-based polymer (SbOC-4SH x 2SH y ). The SbOC-4SH x 2SH y polymer exhibits robust positive-tone behavior attributed to its composition of a large number of fracture-prone sites. Precise modulation of crosslinking density enables controlled dissolution and lithography behavior, achieving 50 nm patterns at EBL with a sensitivity of 290 µC cm − 2 and 25 nm patterns at EUVL with exceptional dose latitude for wide process windows (32.9–217.4 mJ cm − 2 ). Mechanistic studies by X-ray photoelectron spectroscopy (XPS) reveals that radiation-induced network scission dominate the solubility switching for positive-tone lithography. Therefore, this study establishes the polymerization of metal-oxo clusters into cleavable polymers as a universal paradigm to reconcile EUV absorption with positive-tone photoresists requirements, advancing the frontier of semiconductor nanofabrication.
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