A low-power-high-frequency ultrasonic-assisted reflow soldering was established.
Cu/Sn-Ag-Cu/Cu solder joints were fabricated under the influence of ultrasound.
The effect of ultrasonic vibration time on the solder joint properties was studied.
The solder joint microstructure altered significantly after the ultrasonic treatment.
The shear strength of the solder joints was improved after the ultrasonic treatment.