Effects of TiO2 Nanoparticles on Growth Behavior of IMCs between Sn/Cu joint during isothermal stage of soldering

Although Composite solder can improve the reliability of solder joint, there has been much investigations about the influence of NPs on the interfacial reaction of solder joint, underlying mechanism is still far from being understood. Therefore, it is an interesting and valuable work to investigate the growth mechanism of intermetallic compounds (IMC) under the interaction of different NPs. In this study, TiO
2
NPs was introduced at the interface of Sn/Cu solder joint. Combined with high-pressure air purging liquid solder experiment, the effect of TiO
2
NPs on the growth behaviour of Cu
6
Sn
5
at the interface of Sn/Cu solder joint during the heat preservation stage of soldering has been studied. Form this study, it is observed that the Cu
6
Sn
5
grain growth can be significantly hindered with the TiO
2
NPs. At the initial stage of soldering, the number of Cu
6
Sn
5
nucleation increases with the addition of TiO
2
NPs, because it can provide heterogeneous nucleation cites for Cu
6
Sn
5
grains. With the ongoing heat preservation stage, the adsorption of TiO
2
NPs on the surface and grain boundaries of Cu
6
Sn
5
grains decrease the Cu
6
Sn
5
crystal grain surface energy and hinder the diffusion of Cu atoms from Cu substrate to the liquid solder, which will significantly suppress the Cu
6
Sn
5
crystal grain growth.