The process of in situ epoxidation consists of a two-phase system that involves reactions in both phases, mass transfer between phases, and thermodynamic driving forces for the mass transfer. In this paper, we present a model that treats the process as a two-phase system and uses local phase concentrations to calculate reaction and mass transfer rates. The process of in situ epoxidation has been broken down into a set of systematic steps, and rate constants for each step have been determined. A conventional stirred tank reactor, equipped with cooling coils, eliminated the heat and mass transfer limitations so that the true kinetics of in situ epoxidation were observed. It is shown that significantly larger rates (larger by factors of 2-10) are obtained when heat and mass transfer limitations are removed. The two-phase model adequately predicts the epoxidation kinetics over a wide range of temperatures (50-90°C). In addition, the model also correctly predicts the effect of adding an inert solvent.

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High activation energy, chemically amplified resist systems exhibit a 4% to 1 5% volume shrinkage during the post-exposure bake process. Current lithography process simulators do not take this volume shrinkage into account, thus violating the continuity equations used to model the process. This work aims at describing the kinetics ofthe post-exposure bake process by tracking the volume shrinkage observed in high activation resists. A dynamic model is derived and corroborated with experimental results for Shipley UV5. A global simulation technique is then used in conjunction with the models to extract the lithography parameters for these resists.

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A variety of silica aerogels have been prepared by the hydrolysis of TEOS, and dried using supercritical CO2. The shrinkage which occurs during the drying process is dependent on the gel formulation and the extent of aging of the gels in their pore liquor. Such aging normally results in an increased density, modulus and pore size of wet gels. Upon drying the corresponding aerogels show the opposite behavior for modulus and density, which decrease with the extent of aging. Both drying and aging shrinkage were not observed for base-catalyzed gels, and were very small for HF-catalyzed gels. The use of formamide resulted in reduced drying shrinkage and a slightly larger amount of syneresis. Drying shrinkage is associated with the presence of micropores. Shrinkage during drying has been observed using a high pressure view cell and it was found that most of the shrinkage occurred during depressurization. An explanation consistent with the above is proposed.