Study on fracture mechanism of the aged Sn2.5Ag0.7Cu0.1RE/Cu soldering joint with external energy

With ultrasonic vibration and electric field, Sn2.5Ag0.7Cu0.1RE/Cu solder was experimented. Mechanical property and fracture mechanism of aged joint were researched with the modern physical and chemical detection methods. The results show that when ultrasonic power is 88w, time is 60s, electric field is 2 kV/cm, aging treatment temperature is 150°C, aging time is 200h, the shear strength of soldering joint can achieve 21.54 MPa, which is 47.5% higher than that of traditional soldering. The brittle fracture of traditional soldering joint occurred in the IMC layer. While mixed-fracture composed of granular IMC phase and "parabola" shear dimple of brittle and ductile was observed in the interface of the soldering joint with ultrasonic vibration. Particularly, ductile fracture composed of large sized "parabola" shear dimple was detected in the soldering seam of the aged joint with ultrasonic vibration and electric field.