Interfacial compounds growth of SnAgCu(nano La2O3)/Cu solder joints based on experiments and FEM

• 0.1 wt.% La2O3 nano-particles are selected as the additives into these solders for further improve the property.
• The La2O3 nanoparticles can reduce the diffusion coefficient and activation energies of IMC layers.
• It is found that the La2O3 nanoparticles can enhance the reliability of SnAgCu/Cu solder joints.

SnAgCu alloys are promising as the lead-free solders for replacing traditional SnPb solders, 0.1 wt.% La2O3 nano-particles are selected as the additives into these solders for further improve the property. The interface reaction and the growth kinetics of intermetallic compounds (IMC) at SnAgCu/Cu and SnAgCu-nano La2O3/Cu interface were investigated during thermal cyclic loading. The growth rate of IMC in SnAgCu-nano La2O3/Cu is lower than that of SnAgCu/Cu, the La2O3 nanoparticles can reduce the diffusion coefficient and activation energies of IMC layers. And the finite element simulation demonstrates that von Mises stress concentrates at the Cu3Sn layer near Cu6Sn5 layer, the crack can be found in the stress concentrated area in the experiment, and SnAgCu-nano La2O3/Cu shows small length of crack comparing with SnAgCu/Cu, which demonstrates the La2O3 nanoparticles can enhance the reliability of SnAgCu/Cu solder joints.