Title :
Interfacial reactions between Sn-3.8 Ag-0.7Cu solder and Ni-W alloy films
Author :
Chew, C.S. ; Haseeb, A.S.M.A. ; Johan, Mohd.Rafie
Author_Institution :
Faculty of Engineering and Science, Department of Mechanical and Materials Engineering, University Tunku Abdul Rahman, Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur, Malaysia
Abstract :
In this study, interfacial reactions between Ni-W alloy films and Sn-3.8Ag-0.7Cu solder have been investigated. Ni-W alloys films with tungsten content in the range of 5.0 – 18.0 at.% was prepared on copper substrate by electrodeposition in ammonia citrate bath. Solder joints were prepared on the Ni-W coated substrate at a reflow temperature of 250 °C. The solder joint interface was investigated by cross-sectional scanning electron microscopy, energy dispersive X-ray spectroscopy and electron back scatter diffraction. It has been observed that a (Cu,Ni)6Sn5 layer formed on the Ni-W alloy film after reflow. The thickness of the (Cu,Ni)6Sn5 layer was found to decrease with the increase of tungsten content in the Ni-W film. An additional layer with a bright appearance was also found to form below the (Cu,Ni)6Sn5 layer. The bright layer was identified to be a ternary phase containing Sn, Cu, W and Ni. The bright layer is found to be amorphous and is suggested to have formed through solid state amorphization caused by anomalously fast diffusion of Sn into Ni-W film.
Conference_Titel :
Electronic Manufacturing Technology Symposium (IEMT), 2012 35th IEEE/CPMT International
Conference_Location :
Ipoh, Perak, Malaysia
Print_ISBN :
978-1-4673-4384-8
Electronic_ISBN :
1089-8190
DOI :
10.1109/IEMT.2012.6521744