Tin-Oxo Nanocluster Extreme UV Photoresists Equipped with Chemical Features for Atmospheric Stability and High EUV Sensitivity

To unlock the full potential of extreme ultraviolet lithography (EUVL) utilizing high numerical aperture (NA) optics, tin-oxo nanoclusters (TOCs) have emerged as a promising platform for photoresists (PRs). Although TOC-based PRs offer distinct advantages, their intrinsic Lewis acidity must be carefully managed to prevent undesirable interactions during lithographic processing. To address this, fluoroalkylated TOCs are devised, exploiting the unique properties of carbon–fluorine (C–F) bonds. By employing targeted counter-anion selection, N-TOC6 is synthesized, a material exhibiting robust etch resistance and solubility-switching behavior under EUV exposure, demonstrating the potential of fabricating sub-10 nm patterns. Supported by ¹⁹F NMR and XPS analyses, it is proposed that the presence of C–F bonds reduces the affinity of Sn atoms for airborne Lewis basic molecules by forming coordination contacts with the Lewis acidic Sn centers, thereby improving pattern stability post-exposure. Additionally, N-TOC6 exhibits chemical orthogonality with non-fluorinated TOCs, facilitating bilayer stacking that enhances EUVL sensitivity. This study highlights the critical role of fluorine chemistry in achieving high-performance, energy-efficient lithographic materials for next-generation chip manufacturing in the artificial intelligence era.