Study on the reliability of solder joined on the aluminum layer using an ultrasound assisted soldering

This work was to verify the reliability of the solder joined on the aluminum layer using an ultrasound assisted soldering after it was subjected to damp heat test. The shear strengths of solders decrease with increasing the test durations. Neither cracks nor defects were found in joining interface and the fracture existed solder beads after the shear test, implying the joining performance would not degraded. The grain growth of the solder results in shear strength decreased after damp heat test.