Modification of SAC0307/Cu solder joints by FeCoNiCrCu particles: microstructure, comprehensive properties and aging reliability

The effects of adding varying amounts of FeCoNiCrCu particles on the microstructure, interfacial reaction, wettability, shear strength, and isothermal aging reliability of SAC0307/Cu solder joints were systematically investigated. The results indicate that an appropriate addition of FeCoNiCrCu particles effectively refines the microstructure of SAC0307/Cu solder joints and suppresses the growth of the interfacial intermetallic layer. When 0.1 wt.% FeCoNiCrCu particles were added, the intermetallic layer thickness was reduced from 1.81 μm to 1.56 μm. With a FeCoNiCrCu particle concentration of 0.1 wt.%, the spreading area of the SAC0307 solder increased by 7.75% compared to the initial solder, and the shear strength rose from 24.35 MPa to 26.14 MPa. After 500 h of isothermal aging at 150°C, the intermetallic layer thickness increased to 8.30 μm for the SAC0307/Cu solder joint and 7.58 μm for the SAC0307-0.1FeCoNiCrCu/Cu solder joint, while the shear strength dropped to 19.07 MPa and 22.0 MPa, respectively.