| Summary: | 碩士 === 義守大學 === 材料科學與工程學系 === 87 === Encapsulation is one of the important steps in IC packaging processes. The yield is highly affected by the residual stress in the packages, which results from the chemical shrinkage due to crosslinking and physical shrinkage during cooling. In this work, a low stress matrix resin is synthesized by adding dimethylvinyl polysiloxane into the o-cresol-formaldehyde novolac epoxy resin (CNE) to form a simultaneous interpenetrating network (SIN). The rate of reaction of CNE is controlled by varying the amount of triphenyl phosphine (TPP), and that of polysiloxane controlled by using the cross-linking agent of dicumyl peroxide. The effects of TPP and DCP in each system can be obtained from the relation between heat of reaction and glass transition temperature, Tg. Differential scanning calorimetry is employed to investigate the reaction kinetics, which reveal that the Arrhenius and Kamal’s reaction schemes successfully model the polysiloxane and epoxy systems, respectively. The prepolymers are prepared according to the kinetic calculations. The method of synthesis can be either through direct blending or through a grafting reaction. The mechanical properties of CNE, SIN, and both CNE and SIN with silica filler are tested. As compared with CNE, the SIN has lower Young’s modulus and tensile strength, and the CNE with silica filler has slightly higher values of both properties. It has observed that, for the CNE with silica filler after having been formed as SIN, its modulus and tensile strength are lowered, and its strain at break increased. Tests of dynamic mechanical properties have been conducted to establish the relationship between storage modulus and temperature, and found that the storage modulus of CNE is lowered after forming into SIN. A thermal gravimetric analyzer is utilized to study properties of coefficient of thermal expansion above or below Tg of various epoxy resins with and without silica filler, which enables us to gain insight into the behaviors of cross-liking shrinkage during encapsulation. Tests of moisture absorption are conducted to study the effects of Tg and SIN on the moisture absorptivity. Measurements of viscosity are made to assist in predicting optimal encapsulation temperature and filling time. As for resistance of flammability, the SIN made exhibits higher pyrolysis temperature without gain of its residual weight. Facing ever-stringent requirements of IC encapsulation it has been found that the polysiloxane-CNE SIN is a promising encapsulant.
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