Interfacial Reaction between Zn-25Sn-xTi Pb-free Solder Alloys and Cu Substrate under Multiple Reflow

• Main Authors: WilliamHonggo, 吳詩良
• Other Authors: Kwang-Lung Lin
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/v44wm7

碩士 === 國立成功大學 === 材料科學及工程學系 === 106 === The microstructure and growth behavior of intermetallic compound (IMC) formed between Zn-25Sn-xTi (x = 0,0.02,0.05,0.08) and Cu were investigated at high temperature (415°C) and low temperature (220°C) in this study. Microstructure observation of the solder alloys at high temperature shows that CuZn5, Cu5Zn8, CuZn were formed at the interface. The CuZn5 and Cu5Zn8 IMC were formed at the interface after one reflow. The thickness increased with increasing reflow number up to 10. After ten reflows, a third IMC layer appeared with the same planar shape and identified to be CuZn. The growth mechanisms were investigated and showed that Cu5Zn8 growth follows diffusion controlled reaction, while the CuZn5 follows reaction controlled mechanism. The multiple reflow experiment was also conducted in lower temperature (220°C) for the as-reflowed joint. The thickness of CuZn5 decreased with the increase of the titanium added although no apparent change of total IMC thickness. After establishing the IMC growth mechanism of the high temperature Zn-25Sn-xTi solders, the specimens aged to investigate its interfacial reaction behavior during aging. The growth rate of the IMC increased with the increase of the titanium added.