A Study on Influence of Cu₃Sn Phase Thickness on Shear Performance of Cu-Sn IMC Joint

The shear deformation and fracture behavior of Cu-Sn intermetallic compound (IMC) joints with different thicknesses of Cu₃Sn phases without current (0 A/cm²) and with current (3×10² A/cm²) stressing are studied in this paper. The results show that: whether under current stressing or not, the equivalent modulus and shear strength of the joints increase with the increase of Cu₃Sn phase thickness, and the maximum strength is 89.1 MPa (0 A/cm²) and 83.2 MPa (3×10² A/cm²) respectively; the equivalent modulus and shear strength of the joints decrease under current stressing, and the decrease rate decreases with the increase of Cu₃Sn phase thickness, which indicates that Cu₃Sn phase has better current resistance than Cu₆Sn₅ phase; with the increase of Cu₃Sn phase thickness, the fracture (a brittle fracture) position of the joints gradually changes from Cu₆Sn phase to the phase interface between Cu₆Sn₅ and Cu₃Sn and finally in the Cu₃Sn phase whether under current stressing or not. These research results provide necessary data support and theoretical support for the accurate evaluation of the reliability of Cu-Sn IMC joints.