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Quenching studies on the luminescence emission of Ru(bpy),*+ with ferrocyanide ion, 9-methylanthracene, and doxylstearic acids have been carried out in hemimicellar and micellar aggregates to gain insight into the location of this Raman and luminescence probe. Ru(bpy),*+ is bound to a more nonpolar hemimicellar hydrophobic region as evidenced from the observed larger Stokes shift in this case than in the case of a micellar environment. Stern-Volmer constants for the doxylstearic acid quenching of R~(bpy),~+ luminescence in micelles indicated that the optical electron in the MLCT state of the probe molecule resides in a bipyridyl ring which appears to be close to position 7 of the stearic acid chain.

In a search for alkane candidates for 193 nm immersion fluids, several alkanes and cycloalkanes were synthesized, purified, and screened to ascertain their absorption at 193 nm, refractive index, and temperature dispersion coefficient in the context of the actual application. In general, cycloalkanes, and more specifically polycycloalkanes, possess a higher refractive index than do linear alkanes. Decalin, cyclodecane, perhydrophenanthrene (PHP), perhydrofluorene (PHF), and perhydropyrene (PHPY) are examined as potential second- and third-generation immersion fluids. The use of perhydropyrene, which possesses a high refractive index of 1.7014 at 193 nm, may be limited as an immersion fluid because of high absorption at 193 nm. Mixtures of cycloalkanes can lead to a higher enhancement of the refractive index together with a decrease of the viscosity. Exhaustive purification of the fluids is a critical step in determining the real absorption of the different fluids at 193 nm. Even very small traces of impurities possessing a high absorption coefficient at 193 nm can lead to an unacceptably high level absorption at 193 nm, previously incorrectly attributed to the alkane instead of the absorbing impurities.

Abstract— –The role of surfactants as deaggregating agents for the laser dyes is investigated by spectrophotometry using Rhodamine 6G as a representative. A method to estimate the fraction of dye present as monomer, dimer and as a monomer‐surfactant (monomer or micelle) complex is described. It is shown that among the surfactants, cetyl trimethyl ammonium bromide, Triton X‐100, sodium lauryl sulfate (SLS) and potassium oleate, the anionic ones are the most effective in suppressing the aggregation of Rhodamine 6G. While the non‐ionic surfactant is found to be effective only above its critical micellar concentration, the cationic surfactant has no effect on aggregation. The optimum concentration of SLS needed for suppression of dye‐dimers is estimated.

consolute phase boundary.11 However, the values increase slightly for C12AC but scarcely for C16DAC, CUDAC, and C14DAB, as the temperature approaches the consolute boundary of the liquid-liquid phase separation. Therefore, the rigidity or expansion of rodlike micelles is not necessarily related to the liquid-liquid phase separation.The difference in the rigidity or expansion of rodlike micelles seems to manifest itself in the shear rate dependence of the viscosity. The shear thickening phenomenon was observed for almost all of aqueous sodium halide solutions of C16DAC, C14DAC, C14DAB, and C12AC, rodlike micelles of which may have more expanded character: the relative viscosity shows the shear thickening at low shear rates, before the shear thinning occurs. The expanded long rodlike micelles entangle further at low shear rates, and then entangled micelles are aligned or destructed at high shear rates. On the other hand, shear-induced association may occur for shorter rodlike micelles of C12AC.The strong shear thinning or pseudoplastic behavior happened for solutions of more flexible rodlike micelles of C16TAC, C16TAB, and C14TAB.9 The entanglement of such flexible micelles can be aligned or destructed easily, if the shear stress is applied. The same discussion can be applicable to the shear rate dependence on the viscosity of aqueous NaCl solutions of C"E7. As the rigidity or expansion of rodlike micelles increased with a rise in temperature, the relative viscosity changed from shear thinning to shear thickening.11The shear rate dependence on the viscosity was reported for aqueous NaBr solutions of alkylpyridinium salicylate, aqueous solutions of tetradecyltrimethylammonium salicylate, and their mixture.25,26 The possibility of the shear-induced phase transition was suggested for these solutions.

In order to find new immersion liquids to improve the resolution of 193 nm immersion photolithography, we have attempted to discover aqueous system possessing an index of refraction greater than that of water using aqueous surfactant systems. The index of refraction (RI) of both cationic and anionic surfactant systems were examined in the presence of wide range of inorganic salts, and parameters such as size of surfactants, concentrations, and temperature were varied. The refractive index (RI) was found to be increased in the presence of both anionic and cationic surfactants compared to those of water and also increased as a function of surfactant concentration. However the refractive index tends to increase much more strongly as a function of salt concentration. In our study, a maximum RI enhancement was observed from 6.5 M CdCl 2 in 8.2 mM aqueous SDS solution. The effect of micellar properties such as the critical micelle concentration (cmc) and degree of ionization were systematically studied for aqueous SDS system in the presence of CdCl 2 . The correlation on index of refraction between empirical data and theoretical prediction were performed using the concept of molar refraction. Wavelength dependence of RI from theoretical prediction based on empirical equation was examined for various concentration of CdCl 2 system and the results are reported in the paper.Subject terms: index of refraction, immersion photolithography, ionic surfactants, 193 nm, SDS, CTAC, CdCl 2 IntroductionRecently, optical lithography has been incrementally marching toward dimensions less than 45 nm. The wavelength has been reduced to 193-nm and 157-nm lithography using F 2 laser was studied tentatively for the next generation of lithography. We have been studying the mechanism of the photodegradation that leads to darkening of polymer pellicles during exposure to 157 nm radiations in order to design new soft pellicle systems that possess acceptable characteristics for 157 nm photolithography.

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