Cross-Interaction of Ni and Cu in Sn

• Main Authors: Quei-Pin Li, 李魁斌
• Other Authors: C. R. Kao
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/02562079100995322371

碩士 === 國立中央大學 === 化學工程與材料工程研究所 === 93 === In a real solder joint, the solder is always sandwiches between two metals. And the Ni/solder/Cu combination is one of the most common one in microelectronics devices. The objective of this study is to investigate whether the cross-interaction will occur between the interface of solder/Cu and Ni/solder. In fact, it is reported that the two interfaces of Ni/solder/Cu joint would interact after reflow. Therefore, it is known that the dissolved metal results in the system become complex. As the result, the Ni/Sn/Cu diffusion couples were prepared by electroplating in this study to investigate the cross-interaction of Cu and Ni in solder joint only in solid/solid reaction. Experiments were carried out at 200 ℃ for 15 minutes. It was found that Cu6Sn5 compound existed at both Ni/Sn and Cu/Sn interface. Basing on the result, we can say that the cross-interaction of Ni and Cu in a solder joint occurred very quickly at 200 ℃thermal aging. After long term thermal aging, the reaction product didn’t change at both Ni/Sn and Cu/Sn interface. There is(Cu1-xNix)6Sn5 at Ni/Sn interface and Cu6Sn5、Cu3Sn at Sn/Cu interface.Beside it, we found that the microstructure of these reaction product is different from Sn/Cu and Sn/Ni diffusion couple. In other words, the morphology of IMC is largger variation than Sn/Cu and Sn/Ni diffusion couple. In thermodynamic kinetics, it has been show that the formation of of (Cu1-xNix)6Sn5 over the Ni layer can reduce the Ni consumption rate. At the same time, the Cu consumption rate of the opposite side was accelerated.