| Summary: | 碩士 === 中華大學 === 機械與航太工程研究所 === 91 === In this study, the fracture behaviors of the eutectic Sn-3.5Ag ball-grid array assembly have been evaluated by tensile testing at strain rates of 10-4, 10-5 and 10-6 s-1 at various homologous temperatures. The tensile strength of eutectic Sn-3.5Ag ball-grid array assembly was higher than that of bulk Sn-3.5Ag solder, which might be attributed to the geometric constraining effect of the Sn-Ag solder/Cu interfaces. Two typesof fracture modes were fround during the tensile tests depending on the strain rates and homologous temperatures. At a strain rate of 10-4 s-1 and homologous temperatures lower than 0.65, the main crack propagation occurred at the angle 45° with the tensile axis and along the Ag3Sn/Sn interfaces. However, at strain rates lower than 10-4 s-1 and/or at homologous temperatures higher than 0.65, the tensile crack link-up by the creep voids propagated normal to the tensile axis. A transgranular creep fracture was found on the failed surfaces of Sn-3.5Ag ball-grid array assemblies.
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