Electron‐Induced C─F Bond Activation in Sn ₆ ‐oxo Cluster Resist for Enhanced Sensitivity and Sub‐10‐nm Patterning

Abstract

ABSTRACT Metal‐oxo cluster (MOC) resists are promising candidates for extreme ultraviolet lithography (EUVL), but optimizing the resolution, line‐edge roughness (LER), and sensitivity (RLS) trade‐off remains challenging. Leveraging dissociative electron attachment (DEA) to activate C─F bonds provides a controllable handle to improve this RLS trade‐off, yet remains underexplored. Here, we report a room‐temperature, scalable synthesis of a tunable series of Sn‐oxo clusters and demonstrate hundred‐gram‐scale, single‐batch production. The fluorinated FPAA demonstrates enhanced sensitivity without compromising resolution or LER. Under electron beam lithography (EBL), FPAA achieves a critical dimension (CD) of 9.1 nm and an LER of 2.2 nm, and enables high‐fidelity complex patterning. Additionally, FPAA exhibits robust performance under deep ultraviolet (DUV) lithography and EUVL, achieving a CD of 20.9 nm under EUVL. FPAA also shows exceptional plasma resistance, achieving a high estimated Si:resist etch selectivity of >50:1. Mechanistic analyses indicate that irradiation‐generated low‐energy secondary electrons (LESEs) promote electron‐induced C─F activation, consistent with a DEA‐mediated pathway. Concurrently, organic ligand bridging and Sn─O─Sn network densification occur, forming a crosslinked network that drives the solubility switch. This work elucidates the lithographic mechanisms of Sn‐oxo clusters and provides design principles for MOC resists, supporting progress toward sub‐10‐nm lithographic resolution.