The effects of different ultrasonic treatment time on microstructure evolution and mechanical property of Cu/Sn-3.0Ag-0.5Cu (SAC305) solder joints were investigated. Experiments were set to obtain Cu/SAC305 solder joints, which were compared with solder joints without ultrasonic treatment. The application of short-term ultrasonic treatment on the solder joints would alter the morphology of interfacial intermetallic compound (IMC) layer, IMC thickness and grains size were reduced. Besides, ultrasonic treatment could significantly improve the shear strength of solder joints. In addition, the liquid solder would further flow along the direction of ultrasound, resulting in the reduction of contact angle. Due to the increase of ultrasonic time, the optimal growth direction of grains was changed after the ultrasonic treatment. However, excessive ultrasonic time would reduce the shear strength of solder joints and increase the IMC thickness, which would reduce the stability of solder joints.

研究了不同超声处理时间对Cu / Sn-3.0Ag-0.5Cu（SAC305）焊点组织演变和力学性能的影响。进行实验以获取Cu / SAC305焊点，并将其与未经超声处理的焊点进行比较。在焊点上进行短期超声处理将改变界面金属间化合物（IMC）层的形态，降低IMC厚度并减小晶粒尺寸。此外，超声处理可以显着提高焊点的剪切强度。另外，液态焊料将进一步沿超声方向流动，从而导致接触角减小。由于超声时间的增加，超声处理后晶粒的最佳生长方向发生了变化。然而，