| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 98 === A procedure in soldering reactions between Au/Pd/Ni(P) (0.1/0.2/7, microns) tri-layer structure and two kinds of solders (Sn37Pb and Sn3Ag0.5Cu) were investigated in this study. In Sn37Pb soldering system, it was found that Au layer could disappear within 5 s, which exposed the underlying Pd to form a (Pd,Ni)Sn4 layer. The (Pd,Ni)Sn4 then broke off from the roots of the grains and spalled into the solder after soldering for 15 additional seconds. In turn, the Ni(P) contacted the molten Pb-Sn, forming the intermetallics Ni3Sn4 and Ni3P instead. Ni3P formed a uniform layer that was adjacent to Ni(P) while Ni3Sn4 exhibited needle- or chunk-like grains that were scattered inside the solder, instead of the layered-type morphology that appeared in most eutectic Pb-Sn/Au/Ni(P) systems. Interestingly, the series of soldering reactions changed dramatically when Sn37Pb was replaced with Sn3Ag0.5Cu. First, both Au and Pd were quickly exhausted within 5 s. Subsequently, a dense (Cu,Ni)6Sn5 rather than the scattered Ni3Sn4 became the dominant reaction product that formed adjacent to the solder. Additionally, a thinner Ni3P formed at the interface, specifically for the regions where were covered with (Cu,Ni)6Sn5. The sluggish Ni3P can be attributed to a relatively low Ni consumption by forming a dense (Cu,Ni)6Sn5 layer over Ni(P). A more detailed analysis on the growth of Ni3P in these two soldering systems will be provided in this study.
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