Effect of Electromigration on Microstructure and Properties of Ni-rGO Reinforced Sn2. 5Ag0. 7Cu 0.1 RE Composite Solder/Cu Soldering Joints.

The electromigration microstructure and properties of Ni-rGO reinforced Sn2. 5Ag0.7Cu0. 1RE composite solder/Cu soldering joint was investigated by scanning electron microscope, the energy dispersive spectrometer,the X-ray diffraction and micro-shear test. The results show that the thickness of intermetallic compound( IMC) Cu₆Sn₅ and Cu₃Sn in Sn₂. 5Ag0. 7Cu0. 1RE composite solder/Cu soldering joint increases with current stressing time at the anode by a current density of 1 X 10⁴ A/cm² at 120 T . The thickness of Cu₆Sn₅ decreases and Cu₃Sn increases first and then decreases at the cathode. The addition of Ni-rGO significantly inhibits the growth of Cu₆Sn₅ and the formation of micro-voids in the Ni-rGO reinforced Sn2. 5Ag0. 7Cu0. 1RE composite solder/Cu soldering joint at the cathode by electromigration and increase the shear strength of the soldering joint. The shear strength of Ni-rGO reinforced Sn2. 5Ag0. 7Cu0. 1RE composite solder/Cu soldering joint is 47. 8% higher than that of the soldering joint without Ni-rGO after current stressing for 72 h. The shear fracture of composite solder/Cu soldering joint changes from ductile fracture dominated by dimples at the cathode soldering zone to mixed fracture composed of cleavage, quasi-cleavage and a few dimples in the IMC interface. [ABSTRACT FROM AUTHOR]