Mechanistic Studies of Positive-Tone Organoantimony Resists

We conducted a series of mechanistic studies involving the exposure of antimony carboxylate complexes (R3Sb(O2CR')2) which exhibit positive-tone patterning upon to EUV light or e-beams. The volatile photoproducts were evaluated using in situ mass spectrometry, revealing carbon dioxide and fragments of the R ligands (isopropenyl, isopropyl). Additionally, fragments corresponding to the breaking of the metal-carbon bond and metal-oxygen bond were observed. These results provide evidence that polymerization occurs for photoresists containing terminal olefins, resulting in a nonvolatile R'-group after decarboxylation. Ultimately, we propose a network of plausible mechanistic steps that are consistent with the structure-function and mass-spectral outgassing experiments.