|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Electronic Packaging and Interconnections
||Characterisation of η-(Cu,Ni)6Sn5 formed between Cu-xNi/Sn couples
||Xin Fu Tan, Qinfen Gu, Michael Bermingham, Stuart McDonald, Kazuhiro Nogita
|On-Site Speaker (Planned)
||Xin Fu Tan
The transient liquid phase soldering (TLPS) process between Sn and Cu to form a coherent matrix of Cu6Sn5 intermetallic compounds (IMCs) can be greatly accelerated if, instead of pure Cu, a Cu-xNi alloy is used as a substrate. This enables the formation of a bond that is stable at high temperatures in a time comparable with that of conventional reflow soldering. Depending on the Ni concentration, the (Cu,Ni)6Sn5 IMCs formed are different from the well-studied Cu6Sn5 with altered morphologies and crystal structures, which may influence the mechanical and physical properties of the joint. The IMCs growth rates at different Ni concentrations also have a direct impact on the bonding process in industry applications. In this study, scanning electron microscopy, electron backscatter diffraction, synchrotron powder X-ray diffraction and density functional theory calculations were used to characterise the η-(Cu,Ni)6Sn5 formed between Cu-xNi/Sn couples and to reveal the mechanisms of the accelerated growth.