Effect of reflow soldering on IMC and shear strength of SnAgCu solder joint

Effect of reflow soldering cycles on the interfacial reaction between Sn-0.3Ag-0.7Cu-xNi(x=0,0.05)solder and Cu substrate as well as the shear strength of solder joint were investigated.Results show that the thicknesses of Cu6Sn5 layer and(Cu1-xNix)6Sn5 layer increase as the reflow soldering cycles increase.The addition of w(Ni) of 0.05% to the solder can decrease the thickness of IMC which is independent of the reflow soldering cycles.Furthermore,the shear strengths of solder joints added with Ni or without Ni don't change apparently after the reflow soldering cycles,which are 21 MPa and 25 MPa respectively.The fracture surface is found partly in the bulk solder and partly on the interface between the solder and IMC after five reflow soldering cycles.