Finding Diffusivity and Solubility of Impurities inside ILs By MD

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Ionic liquids (ILs) are promising candidates for use in the semiconductor industry because of their unique and tunable physicochemical properties. They are a novel class of salts with desirable features such as being in liquid phase at room temperature, nonflammability, high ionic conductivity, high thermal stability, and low to negligible vapor pressures. Their physical, chemical, solubility, transport, and solvation properties can be tuned by altering the cations or anions to tailor for applications in the semiconductor industry, including the process of liquid/gas separations, extraction of impurities, and cleaning under vacuum. Selecting suitable ILs to enhance the efficiency of the target semiconductor processes and tools is crucial.One possible application is to use ILs as a barrier or protective liquid film that does not evaporate in low-pressure conditions. For this application, we need a better understanding of the molecular scale of the behavior of the ILs at different temperature ranges. To develop such a new process, the knowledge of absorbing/desorbing impurities (such as O2, CO2, and H2O, including their mixtures and other organic materials) in the ILs and their transport (diffusion coefficients) properties inside the ILs at different temperatures is essential from the surface protection film point of view. This work seeks to answer these essential questions at the nanometer scale by showing the results from molecular dynamics (MD) simulations of the diffusivity and solubility of impurities inside ILs. Examples of MD simulation models for this study are shown in Figure 1, where impurities with the same concentration are placed on both sides of ILs, and the transport behavior of impurities inside ILs is extracted. From these nanoscale results, we can better understand and predict the diffusivity and solubility of impurities inside ILs and find the conditions at which impurities can be removed from ILs for recycling purposes. Figure 1