Antimony‐Oxo‐Cluster‐Based Polymers as Positive‐Tone EBL/EUV Photoresists: Lithography Performance Enhancement by Network Structure Modulation

Abstract 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.