<p>Extreme ultraviolet (EUV) lithography systems operate under limited light intensity. To address this issue and improve lithographic sensitivity, considerable attention has been paid to the addition of atoms (such as F, I, and metal atoms) with high EUV absorption to photoresists. However, the subsequent reaction intensification involved in lithography is always ignored. Herein, the considerable influence of different ligands in photoresists on lithographic sensitivity is reported. The regulated molecular orbitals of metal-oxo clusters can increase lithographic sensitivity besides introducing high EUV-absorbing elements. It is illustrated firstly that aromatic groups with electron-donating groups as ligands provide low vertical ionization potential (VIP) and high occupied molecular orbital to metal-oxo (Zn₂Ti₄O₄) cluster photoresists, drastically increasing photoelectron yields during exposure and ultimately enhancing lithographic sensitivity. The synergistic effect of reduced VIP and double bond crosslinking can considerably reduce the EUV dose required for lithography. Leveraging this synergistic effect, 35 nm (L/S) half-pitch patterns are achieved with only 25 mJ/cm² EUV exposure dose. Thus, the proposed mechanism might prove important for ligand screening for metal-oxo cluster photoresists for advanced lithography.</p>