| 초록 |
Of various high-performance polymers, polyimides have high thermal stability, high chemical resistance and excellent mechanical properties so that they are widely used in the fabrication of multilayer interconnection systems. Despite their high chemical resistance, high thermal stability, and excellent mechanical properties, polyimides are known to still absorb water in some amounts. The water absorbed sometimes causes reliability problems in devices such as metal corrosion and mechanical failure at interfaces. In addition, the water absorbed increases the dielectric constant, resulting in a minimum electrical performance in the devices. In previos studies about this phenomena, Han et al. showed that water uptake and diffusivity in polyimide thin films is related to environmental conditions and morphorogical variations due to imidization history, and film thickness using the x-ray diffracition and prism coupler. One approach to solve these problems relies on the incorporation of flexible hexafluoroisopropylidene groups, -C(CF3)2 into the polymer chain2. Fluorine group increases solubility, resistance to flame, oxidation and environmental degradation and decreases electrical conductivity and water sorption. Despite enhancement of properties, polyimides incorporating fluorine group are affected by chemicals used for fabrication of electronic devices. To understand and classify the effect of fluorine group on diffusion characteristics, thermal stability, and chemical resistance of flexible BTDA-ODA polyimide, we have prepared homo- and copolyimides with various mole fraction dianhydrides (BTDA and 6-FDA) and diamine (ODA). Characteristics of water sorption kinetics and chemical resistance to chemicals were measured by the gravimetric technique. Thermal stability according to the incorporation of fluorine group was characterized using TGA technique. And characteristic peak of general and fluorinated polyimide was investigated by using IR spectroscopic technique.
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