Performance and reliability of solder joints in dual nanometer Cu6Sn5 and Ag3Sn particle-doped modified Sn3.0Ag0.5Cu composite solders

In this study, Ag ₃ Sn and Cu ₆ Sn ₅ nanoparticles were synthesized using the redox method, and SAC305-0.15Ag ₃ Sn- x Cu ₆ Sn ₅ ( x  = 0 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, and 0.2 wt%) composite solder was produced by incorporating these nanoparticles into Sn-3.0Ag-0.5Cu (SAC305) solder. The thermal properties, wettability, microstructure, Vickers hardness, tensile strength, and reliability of the solder joints in these composite solders were systematically investigated. The results demonstrated that the melting point of the composite solder increased upon the addition of dual nanoparticles to the SAC305 solder. The incorporation of Ag ₃ Sn nanoparticles and an appropriate amount of Cu ₆ Sn ₅ nanoparticles inhibited the excessive growth of intermetallic compounds (IMC) within the solder alloy matrix and refined the alloy microstructure. Additionally, the wettability of the solder alloy improved, with the spreading area of SAC305-0.15Ag ₃ Sn-0.15Cu ₆ Sn ₅ composite solder reaching 88.5565 mm², which is 8.50% higher than that of SAC305-0.15Ag ₃ Sn solder. Mechanical property analysis revealed that the solder alloy containing dual nanoparticles exhibited higher Vickers hardness and tensile strength in the solder joints, with maximum values of 12.02 HV and 56.68 MPa, respectively. Aging tests indicated that the addition of dual nanoparticles inhibited the growth of the interfacial IMC layer and reduced the growth coefficient, with a minimum value of 0.0180.