Triphenylsulfonium hexafluoroantimonate

For comparison, the solution quantum yield was determined by the merocyanine dye technique. Acetonitrile solutions of triphenylsulfonium hexafluoroantimonate were irradiated with a 5 m. /cm2 dose. Dye solution was added and the acid content was determined by changes in dye absorption. The quantum yield for acid production was determined to be 0.8, which agrees reasonably well with the value (0.71) determined for the hexafluoroarsenate salt (8). 

Figure 3. UV spectrum of a 1 urn thick film of 80/20 copolymer containing 10 wt% triphenylsulfonium hexafluoroantimonate.

Imaging studies were done on copolymers prepared by the polymer modification route because of the availability of the precursor polymers of various molecular weights. The protected copolymers were compounded with triphenylsulfonium hexafluoroantimonate (13% w/w) in cyclohexanone. One micron thick films were spin coated on NaCl plates, baked at 140°C for 5 minutes to expel solvent and then subjected to infrared spectroscopic analysis before and after exposure. Exposure to 18 mJ/cm2 at 254 nm caused no change in the infrared spectrum. However, when the films were baked at 140°C for 120 sec. following exposure, deprotection was quantitative based on loss of the characteristic carbonate C = O absorption and... 

Figure 11.19 shows a typical family of IR spectra of a film of resist formulated with triphenylsulfonium hexafluoroantimonate and poly(CBN-co-NBCA), samples of which were exposed to 248-nm radiation doses of 0-50 mJ/cm and... 

Figure 11.21 Arrhenius plot for resist formulated with poly(CBN-co-NBCA) and 3 wt% of triphenylsulfonium hexafluoroantimonate (TPSHFA), and exposed under 248-nm radiation. (Reprinted with permission from American Chemical Society. )...

Synthesis. Diphenyliodonium hexafluorophosphate, Ph2lPF6, and triphenylsulfonium hexafluoroantimonate, PhaSSbFe, were synthesized using literature procedures (25). Tetra-n-butylammonium hexafluorophosphate, TBAPFe, was obtained by direct metathesis between tetra-n-butylammonium bromide (99%) and potassium hexafluorophosphate (tech.), KPFe. 

FIGURE 5.48 Photochemistry of poly(4-t-butoxycarbonyloxy styrene) doped with (a) triphenylsulfonium hexafluoroantimonate, (b) a dry developable polycarbonate, and (c) self-developing polyphthalaldehyde. 

Infra-red spectroscopy and fluorescence spectroscopy provide convenient methods for studying these processes. Using FTIR, we investigated the deprotection kinetics of some of our alicyclic polymer resist systems (2,3) (containing triphenylsulfonium hexafluoroantimonate) that were exposed to 248 and 193 nm... 

Materials. Alicyclic polymers such as poly(CBN-a/t-MAH) and poly(CBN-co-NBCA) were synthesized by free radical and Pd(II)-catalyzed addition polymerization techniques, respectively, the details of which are given in References (2,3) and in (Okoroanyanwu, U. Byers, J. Shimokawa, T. Willson, C.G. Chem. Mater., 1998, in press) (Okoroanyanwu, U. Shimokawa, T. Byers, J. Willson, C.G. Chem. Mater., 1998, in press). Triphenylsulfonium hexafluoroantimonate (TPSHFA) was prepared according to the literature procedure (5). CD 11 anti-reflective coating was obtained from Brewer Scientific Company. BARL antireflective coating was obtained from IBM Corporation. PD-523AD developer, 0.2 IN aqueous tetramethylammonium hydroxide solution with surfactant was obtained from Japan Synthetic Rubber Company. LDD-26W developer, 0.26N aqueous tetramethylammonium hydroxide, was obtained from Shipley Company. 

When the photoacid generator, triphenylsulfonium hexafluoroantimonate, is exposed to radiation, it decomposes to release the super acid, hexafluoroantimonic acid, in the resist film. While this photochemical reaction can occur at room temperature, the acid-catalyzed deprotection of the pendant r-butyl group of the resist polymer occurs at reasonable rates only at elevated temperature. It is therefore necessary to heat the resist film to an appropriate temperature (postexposure bake) to provide the energy that is required for the acid-catalyzed deprotection of the r-butyl group of the ester, which in turn, affords the base-soluble norbomene carboxylic acid unit isobutylene volatilizes. The extent of deprotection at constant temperature is... 

A new simple and reliable method for monitoring photoinduced acid generation in polymer films and in solutions of the kind used in 193 nm and deep-UV lithography was developed. By using N-(9-acridinyl)acetamide, a fluorescent acid-sensitive sensor, we have been able to study the effects of trifluoroacetic acid and photoacids generated from triphenylsulfonium hexafluoroantimonate on the spectral properties of the acid sensor in THF solution and in alicyclic polymer resist films exposed at 193 nm. In both cases a hypsochromic spectral shift and an increase in fluorescence intensity were observed upon protonation. This technique could find application in the study of diffiisional processes in thin polymer films. 

Functionalized graphene nano-sheets were employed in the formulation of some UV-cured epoxy-based nanocomposites [264]. Bis-cycloaliphatic diepoxidic resin 3,4-epoxycyclohexylmethyl-30,40-epoxycyclohexyl carboxylate was submitted to UV curing in the presence of triphenylsulfonium hexafluoroantimonate as photoinitiator (2 wt%) and various amounts of functionalized graphenes (0.5, 1 and... 

In an explanation of the reasons for choice of such dopant ions, Angelopoulos et al. [79] noted that to obtain a radiation induced insolubility in P(ANi) suitable for certain resist applications, the emeraldine base form must be doped with materials which produce protonic acids when irradiated, primarily "onium" salts such as triphenylsulfonium hexafluoroantimonate. Thus in a typical application, NMP solutions of emeraldine base and this onium salt are mixed and spin coated on a substrate. When exposed to 240 nm UV radiation at ca. 100 - 300 mJ/cm, the initial blue film turns green, characteristic of conductive P(ANi). This conductive P(ANi) is insoluble in NMP, whereas the non-irradiated, blue, non-conductive film is... 

The photopolymerizable formulations were prepared by adding to the monomers, or mixtures containing different additives, 2wt% of cationic photoinitiator (Triphenylsulfonium hexafluoroantimonate, Cyracure UVI6974, as 50% solution in propylene carbonate, from Dow). The films were obtained by coating the mixtures on different substrate and the curing reaction was performed, in air, by using a Fusion lamp (H-bulb), with radiation intensity on the siuface of the sample of 280 mW/cm, and a belt speed of 6 m/min. 

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