posted on 2009-02-11, 16:02authored byJianfeng Li, Farhad Sarvar, David Whalley, David HuttDavid Hutt, Mike P. Clode, Samjid H. Mannan
Liquid solder joints have previously been proposed in
order to improve the reliability of solder joints in general, and
especially for those that are operated at elevated temperatures.
The solder is designed to melt during high temperature
operation, releasing the stresses on the joint. The component
will remain mechanically attached to the substrate by use of a
polymer underfill or glob-top. Assemblies of dummy insulated
gate bipolar transistor (IGBT) devices were constructed using
the In-Sn as a low melting point solder and Nb as a barrier
layer, on both device bond pads and connecting wires.
Silicone and epoxy based adhesives were used as glob top
materials, and alumina was used as the substrate. Thermal
cycling carried out between -20 and +125 °C lead to rapid
joint failure, and analysis of the joints showed that the wires
had moved under mechanical tests. Further testing is
underway.
History
School
Mechanical, Electrical and Manufacturing Engineering
Citation
LI, J. ... et al, 2007. Failure mechanisms of dummy IGBT assembles constructed using liquid in-Sn/Nb system. IN: Proceedings, 9th IEEE Electronics Packaging Technology Conference, EPTC 2007, Singapore, 10-12 Dec. 2007, pp. 43 - 46