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- x Cu/Cu TLP joints was investigated. The results show that Cu/In- x Cu/Cu joint is mainly composed of an In and Cu 11 In 9 phase after bonded for 60 min. A small amount of Cu 2 In 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 Cu 2 In in the joint increased, the porosity decreased and the shear strength increased with increasing Cu content. When the Cu content of the In- x Cu solder was 45 wt.%, the shear strength of the Cu/In-45Cu/Cu joint reached the peak value of 15.7 MPa.