Options for high index fluids for third generation 193i lithography

Successful fluids for use in 3^rd generation 193 nm immersion lithography must have refractive indices of ≥ 1.80 at 193 nm, ≤ 0.15/cm absorbance at 193 nm, and be photochemically inert to 193 nm radiation. Various classes of organic compounds were prepared and evaluated for use as 3 ^rd generation 193 nm immersion fluids. Functional groups that were evaluated included: sulfones, sulfoxides, sulfonic acids, ammonium sulfonate salts, alkanes, alkyl chlorides, alkynes, and nitriles. Several compounds were synthesized including three sulfone and three sulfonic acid compounds. Other commercially available compounds of interest underwent extensive purification prior to evaluation. Although this work did not lead to any specific solutions to the challenge of identifying 3rd generation 193 nm immersion fluids, it can be concluded that high density hydrocarbons based on cubane may have the best chance of meeting these goals.