• Journal of the Korean Chemical Society
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• v.60 no.2
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• pp.111-117
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• 2016

In this article, new Gibbs free energy of mixing is derived when there are specific interactions between solvent-solute molecules and between solute-solute molecules in binary solutions. It is asssumed that a probability of specific interactions satisfies a binomial distribution. Using this Gibbs free energy of mixing, we investigate possible types of partial miscibilities and show that Ω-shaped temperature-composition phase diagrams can exist. We calculate Ω-shaped temperature-composition phase diagram of water-2-butanol system and compare that with result calculated by the method of Hino⁵ et al. and the experimental data.

• Transactions on Electrical and Electronic Materials
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• v.15 no.6
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• pp.305-308
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• 2014

Organosilyl-modified and star-shaped poly (${\varepsilon}$-caprolactone) (m-PCL) was prepared, and added to polymethylsilsesquioxane (PMSSQ), to make composites. The end groups of m-PCL are chemically similar to PMSSQ, and m-PCL mixed well with PMSSQ in the composite. Porous PMSSQ film was made by further calcination of the composite film at elevated temperature. m-PCL-templated PMSSQ and the as-prepared porous PMSSQ were structurally, optically, and thermally characterized in thin films. The chemical binding of m-PCL and PMSSQ effectively suppressed the phase separation of PMSSQ and m-PCL during the curing process. After calcination at elevated temperature, there remained many pores in the PMSSQ matrix. The refractive indices of the resulting porous PMSSQ thin films decreased with increase of the film porosities, depending on the initial m-PCL loadings.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.48-48
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• 2002

It is generally accepted that ultra low dielectric interlayer dielectric materials (k < 2.2) will be necessary for ULSI advanced microelectronic devices after 2003, according to the International Technology Roadmap for Semiconductors (ITRS) 2000. A continuous reduction of dielectric constant is believed to be possible only by incorporating nanopores filled with air (k = 1.0) into electrically insulating matrices such as poly(methyl silsesquioxane) (PMSSQ). The nanopo.ous low dielectric films should have excellent material properties to survive severe mechanical stress conditions imposed during the advanced semiconductor processes such as chemical mechanical planarization process and multilayer fabrication. When air is incorporated into the films for lowering k, their mechanical strength has inevitably to be sacrificed. To minimize this effect, the nanopores are controlled to exist in the film as closed cells. The micromechanical properties of the nanoporous thin films are considered more seriously than ever, particularly for ultra low dielectric applications. In this study, three approaches were made to design and develop nanoporous low dielectric films with improved micromechanical properties: 1) wall density increase of nanoporous organosilicate film by copolymerization of carbon bridged comonomers; 2) incorporation of sacrificial phases with good miscibility; 3) selective surface modification by plasma treatment. Nanoporous low-k films were prepared with copolymerized PMSSQ and star-shaped sacrificial organic molecules, both of which were synthesized to control molecular weight and functionality. The nanoporous structures of the films were observed using field emission scanning electron microscopy, cross-sectional transmission electron microscopy, atomic force microscopy, and positronium annihilation lifetime spectroscopy(PALS). Micromechanical characterization was performed using a nanoindentor to measure hardness and modulus of the films.