Experimental study on thermal cycling of nano-silver and nano-silver coated tin flip solder joints

In this paper, nano-silver and nano-silver coated tin solder joints with hot pressing bonding conditions of 250 degrees C, 2 min and 15 MPa were selected to study the shear strength of solder joints and their service reliability under hot cycling conditions. The main conclusions are as follows: The addition of nano-tin plays a dispersion strengthening role, which increases the shear strength of nano-silver solder joint from 40 MPa to 50 MPa. After thermal cycling, the main failure mode of the nano-silver-coated tin solder joints is ductile fracture. The main failure mode of the nano-silver solder joints is brittle fracture, firstly, the delamination appears at the interface, and then the crack passes through the outer side of the solder joints, showing cleavage fracture of the grain. The thermal fatigue life of the nano-silver solder joint is 145 cycles, and the thermal fatigue life of the nano-silver-coated tin solder joint is 175 cycles.