Sub‐3 nm Ruthenium Nanopatterns Enabled by Pattern Transfer From Supramolecular Dendrimer Templates

The fabrication of inorganic‐based nanopatterns with feature sizes below 3 nm remains a fundamental challenge in nanoscience and advanced manufacturing. Existing approaches, including extreme ultraviolet lithography, block copolymer self‐assembly, and colloidal nanocrystal patterning, struggle to reliably achieve such dimensions while maintaining long‐range order and structural fidelity. Here, we present a pattern transfer technique from a supramolecular dendrimer templating strategy that enables highly ordered sub‐3 nm ruthenium‐based nanostructures over large areas (1 µm × 1 µm). The pristine dendrimer template forms a hexagonally packed cylindrical morphology with sub‐5 nm periodicity, exhibiting structural stability and long‐range order. Thermal annealing induces cooperative self‐assembly into a single‐domain array, which is selectively stained with RuO 4 to generate an inorganic RuO 2 core while preserving structural registry. This Ru‐incorporated dendrimer architecture shows markedly enhanced thermal and structural stability. Electron microscopy and elemental mapping confirm vertically aligned cylindrical domains with high pattern fidelity. Subsequent calcination at 250°C removes unstained organic components without structural collapse, yielding periodic Ru‐based nanostructures with a characteristic feature size of ∼2.5 nm. This work establishes a versatile bottom‐up platform for ultrahigh‐resolution patterning beyond current lithographic limits and provides a scalable route toward next‐generation nanoelectronic, catalytic, and quantum device architectures.