Wettability, porosity and mechanical properties of ultrasonic-aided laser reflow soldering lead-free solder Sn-3.0Ag-0.5Cu (SAC305) on Cu pad have been investigated at ultrasonic vibration (USV) of different power. The parameters of laser reflow soldering are determined by the wetting experiment, and the effects of different ultrasonic powers on the performance of the solder joint are studied. Results showed that USV can improve wettability without keyholes on top of the solder joint, and the contact angle between the solder joint and the substrate decreases first and then increases as the ultrasonic power increases. The cavitation effect caused by USV effectively reduces the porosity of the solder joints. When the ultrasonic power is 225 W, the porosity of the solder joint is reduced from the initial 13.2% to 5.2%. Through X-ray Diffraction (XRD) analysis of the solder joint matrix, all solder joints have diffraction peaks of [Formula: see text]-Sn, Cu6Sn5 and Ag3Sn, and the solder joints show higher diffraction peak intensity with USV treated. Furthermore, the solder joints prepared by ultrasonic-aided laser reflow soldering show better shear strength compared with laser reflow soldering.

中文翻译：

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超声功率对超声辅助激光回流焊润湿性、孔隙率和力学性能的影响

在不同功率的超声振动（USV）下，研究了铜焊盘上超声辅助激光回流焊接无铅焊料Sn-3.0Ag-0.5Cu（SAC305）的润湿性、孔隙率和力学性能。通过润湿实验确定了激光回流焊的参数，研究了不同超声波功率对焊点性能的影响。结果表明，在焊点顶部没有键孔的情况下，USV可以提高润湿性，并且随着超声功率的增加，焊点与基板之间的接触角先减小后增大。USV引起的空化效应有效地降低了焊点的孔隙率。当超声波功率为225 W时，焊点的孔隙率从最初的13.2%降低到5.2%。6锡5和银3Sn 和焊点在 USV 处理后表现出更高的衍射峰强度。此外，与激光回流焊接相比，超声波辅助激光回流焊接制备的焊点具有更好的剪切强度。