Polarity-engineered Sn-Ti cluster photoresists for sub-10-nm high-resolution lithography

High-performance photoresists are essential for advancing semiconductor technology into the sub-3-nm process node. However, photoresist performance has long been constrained by the trade-off among resolution (R), line edge roughness (L), and sensitivity (S), with the simultaneous enhancement of sensitivity and resolution remains a challenge. In this study, we propose a strategy to overcome the RLS trade-off by enhancing the polarity of metal-oxo clusters. A series of Sn-Ti clusters with increasing polarity were synthesized by adjusting the bridging ligands and reducing the number of low-polarity ligands. Experimental results confirm that, as the developer polarity decreases, higher polar Sn-Ti clusters exhibit a more pronounced enhancement in sensitivity. The highest-polarity cluster, TS-3, undergoes a significant polarity switch upon exposure, enabling simultaneous improvement in sensitivity and resolution under lower-polarity developers, ultimately breaking the conventional RLS trade-off. TS-3 delivers superior patterning performance in both electron beam lithography and extreme-ultraviolet lithography, with a minimum linewidth of 8 nm. This study enhances the understanding of the solubility-transition mechanism in cluster photoresists and provides a new approach for the development of high-performance photoresists.