Mechanistic studies of positive-tone organoantimony resists

We conducted a series of mechanistic studies to elucidate how several antimony carboxylate complexes (R₃Sb(O₂CR')₂) produce positive-tone imaging when irradiated with EUV light or electron-beams. An ablation study demonstrated that compounds containing the styrene carboxylate ligand (-O₂CC₆H₄CH=CH₂) do not ablate while compounds without this ligand do ablate. Volatile photoproducts were identified using mass spectroscopy when irradiated with either EUV light or electron beams. These photoproducts include carbon dioxide and fragments of some of the R and R’ groups. A mechanism is proposed in which the styrene carboxylate ligand plays a pivotal role, by first polymerizing (thermally or as a result of low levels of flare) then decomposing to produce carboxylates or metal fragments that are soluble in aqueous base developer.