Effect of electric current stressing on the shear strength and fracture behavior of micro-scale BGA structured Cu/Sn–3.0Ag–0.5Cu/Cu joints

Shear performance and fracture of BGA structured Cu/Sn-3.0Ag-0.5Cu(SAC305)/Cu joints under current stressing were characterized. Solder joints undergoing electric current stressing have lower shear strength, and fracture tends to take place near the interface between the solder and the intermetallic compound (IMC), and shear fracture strength of the joints decreases with increasing current density. In addition, under electric current stressing, fracture largely occurred mainly by mixed ductile-brittle mode. The temperature of the joints increases greatly upon applying electric current as confirmed by finite element simulation (FE simulation), which is induced by the Joule heating effect. Moreover, the phenomenon of local melting has been observed in solder joints with electric current stressing.