Investigation of the Tin-Oxo Cluster TOC-21 as a Resist for Electron Beam Lithography

The present work investigates the patterning capabilities of the tin-oxo cluster Sn14(μ3-O)12(μ2-O)4(μ2-OH)4(PZ)8(HPZ)4Cl12 (TOC-21) as a negative-tone electron beam resist. Thin film of TOC-21 was deposited on silicon substrates via spin coating, and their lithographic performance was analyzed using high-resolution electron beam exposure. Atomic force microscopy (AFM) revealed the formation of uniform nanoscale features, with TOC-21 stripes reaching heights of approximately 25 nm. Dose curve analysis allowed the determination of the critical exposure dose, providing optimized parameters for high-fidelity nanostructure formation. The study demonstrates that TOC-21 undergoes controlled cross-linking under electron beam irradiation, with pyrazole ligands and bridging oxides maintaining structural stability. These properties result in high sensitivity, resolution, and reproducibility, confirming TOC-21 as a promising material for advanced electron beam lithography and next-generation nanofabrication applications.