Study on Microstructure and Shear Property of Cu/In-xCu/Cu Transient Liquid Phase Bonding Joints

Transient liquid phase (TLP) bonding is a promising interconnection technology for high-temperature electronic packaging. In this paper, the effect of Cu particles on the microstructure and shear property of Cu/In-xCu/Cu TLP joints was investigated. The results show that Cu/In-xCu/Cu joint is mainly composed of an In and Cu(11)In(9)phase after bonded for 60 min. A small amount of Cu2In phase forms at the interface of Cu/Cu(11)In(9)with bonding time exceeding 300 min. The bonding efficiency and shear property of In-Cu mixed particle solder joint are superior to that of the In foil solder joint, because the bonding time was reduced and the shear strength of the solder joint was improved. The phase composition of Cu(11)In(9)and Cu2In in the joint increased, the porosity decreased and the shear strength increased with increasing Cu content. When the Cu content of the In-xCu solder was 45 wt.%, the shear strength of the Cu/In-45Cu/Cu joint reached the peak value of 15.7 MPa.

Automated summary

The study reveals that Cu particles have a significant impact on the microstructure and shear property of Cu/In-xCu/Cu TLP joints, with increasing Cu content leading to improved shear strength of the joints. In-Cu mixed particle solder joints show higher bonding efficiency and shear property compared to In foil solder joints.