Cycloalkyl Ligand-Engineered Zirconium-Oxo Clusters for Sub-9 nm Electron Beam Lithography with Ultralow Line Edge...

Photoresists are key materials for pattern transfer in semiconductor manufacturing, and their performance directly determines lithography accuracy and device quality. Achieving a sub-10 nm line width (LW) with a line edge roughness (LER) of <2 nm remains a major challenge in next-generation semiconductor manufacturing. Herein, we report a cycloalkyl ligand engineering strategy for carboxylic acid-modified zirconium-oxo clusters (Zr₆O₈) and investigate their structure, processability, and lithographic performance. Systematic screening of four cycloalkanecarboxylic acid ligand-modified Zr₆O₈ samples reveals that cyclopropanecarboxylic acid-modified Zr₆O₈ exhibits insufficient solubility for lithographic processing. Moreover, cyclobutanecarboxylic acid-modified Zr₆O₈ is obtained as an oily product, precluding full structural characterization, and cyclohexanecarboxylic acid-modified Zr₆O₈ displays relatively low sensitivity under electron beam lithography (EBL). In contrast, cyclopentanecarboxylic acid-modified Zr₆O₈ can be isolated as a crystalline solid and produces high-resolution EBL patterns with an LW of 8.65 nm and an LER of only 1.28 nm. These results demonstrate that cycloalkyl ligand engineering effectively modulates the lithographic performance of Zr₆O₈. The high-resolution, low-LER patterning capability achieved herein establishes these clusters as a promising platform for next-generation nanolithography and offers a viable strategy for designing high-Z metal-oxo cluster photoresists.