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Photoacid Generator Dispersion in Partially Fluorinated Photoresist Polymers and their Blends



David L. VanderHart, Vivek Prabhu


Solid state proton NMR methods are used to probe the intimacy of mixing in materials relevant to photoresist applications. Bulk blends, made solvent casting, consisted of partially fluorinated polymers and the photoacid generator, di(t-butylphenyl)iodonium perfluorooctanesulfonate (PFOS). Polymers included poly(norbornene hexafluoroisopropanol) (PNBHFA) and the copolymer, poly(norbornene hexafluoroisopropanol-co- t-butyltrifluoromethacrylate) (NBcoTB). Tests for phase separation based on inversion-recovery, solid-echo-spin-diffusion, and chemical-shift-based-spin-diffusion pulse sequences were employed. PFOS, 9% by mass, was shown to be intimately mixed with PNBHFA or with NBcoTB. In 50/50 blends of PNBHFA/NBcoTB, phase separation into domains exceeding 30 nm is observed. However, in the ternary system, containing 9% PFOS to this blend, PFOS is intimately mixed into both phases. Such local scale mixing is necessary to understand for future photoresist materials as feature dimensions are reduced to sub-65 nm.
Chemistry of Materials


blend, iodonium sulfonate, miscibility, NMR, photoacid generator, photoresist, poly(norbornene hexafluoroisopropanol), proton, spin difussion


VanderHart, D. and Prabhu, V. (2008), Photoacid Generator Dispersion in Partially Fluorinated Photoresist Polymers and their Blends, Chemistry of Materials (Accessed May 21, 2024)


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Created October 16, 2008