Abstract
ABSTRACT
The miniaturization of patterns to sub‐20 nm dimensions remains challenging, owing to the fundamental constraints of optical patterning and the increasing complexity and cost of advanced lithographic technologies such as extreme‐ultraviolet lithography. Here, we introduce an electrochemical etching strategy that effectively decouples the final feature size from the optical diffraction limit by leveraging voltage‐gated solubility switching in electro‐responsive polymers. We discover that the redox‐state‐dependent solubility of rhodamine‐based polymers (Poly‐RhNNE‐B) can be precisely modulated by applied potentials, enabling programmable electrochemical dissolution. Notably, redox‐mediator‐facilitated intermolecular charge transfer extends this solubility switching laterally beyond the electrode‐contact regions. This electrochemical lateral etching enables electrically controlled post‐patterning dimensional refinement, allowing the remaining feature width to be progressively reduced after the initial pattern has been defined and yielding a minimum remaining linewidth of ∼17 nm without requiring the final nanoscale dimension to be directly defined by high‐resolution optical exposure. This approach introduces an electrochemical nanofabrication strategy that complements conventional lithographic techniques, potentially reducing process complexity in selected nanoscale pattern‐refinement scenarios while enabling high‐resolution micro/nano‐structuring, thereby expanding the toolbox for next‐generation precision nanomanufacturing.