| Summary: | 碩士 === 國立交通大學 === 機械工程系所 === 96 === The effects of Zn additions on the interfacial reactions with Cu substrates of Sn-0.7Cu (all in wt.% unless specified otherwise) Pb-free solders were investigated. This study was focused on the intermetallic compound (IMC) growth, interfacial reaction and the joint strength as a function of thermal aging and solder composition. Thermal aging was conducted at 150℃ for up to 500 h to accelerate the interfacial reactions between solders and Cu substrates.
The growth of IMCs (Cu6Sn5 and Cu3Sn) in Zn-added solders was slower than those without Zn additions. The growth of the Cu3Sn phase, in particular, was drastically reduced in the Zn-added solders.
The Zn addition was effective in reducing IMCs’ growth (especially Cu3Sn IMCs). In addition, void formation at the interfaces of Sn-0.7Cu was dramatically suppressed by Zn addition. Finally, a mechanism for the beneficial effects of Zn additions on the reduction of IMCs’ growth was discussed. The addition of Zn elements can effectively improve the joint strength of the solder joints.
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