采用光纤激光以振镜扫描的方式对四方扁平封装（QFP）器件进行了焊接实验研究，得到了激光钎焊参数配合SnAg3.0Cu0.5钎料的焊点抗拉强度的变化规律。基于振镜扫描的激光钎焊（11 W, 20 mm/s或8 W, 10 mm/s）不仅能够获得力学性能优良的无铅焊点，而且焊接速度大大提高。通过比较连续光纤激光钎焊、脉冲光纤激光钎焊和红外再流焊SnAg3.0Cu0.5钎料焊点的抗拉强度，表明连续光纤激光钎焊能明显地提高焊点的力学性能。同时对比研究了两种钎料SnAg3.0Cu0.5和Sn63Pb37在连续光纤激光焊的抗拉强度，表明SnAg3.0Cu0.5焊点的力学性能更加突出。焊点的拉伸断面显微形貌显示为塑性断裂，焊缝金相组织细密，界面过度平缓，生成了金属间化合物Cu6Sn5。

Soldering technology for quad flat pack (QFP) devices is studied using a fiber laser based on scanning galvanometer with SnAg3.0Cu0.5 solder and the relationships between tensile strength of micro-joints and laser soldering parameters are obtained. Excellent lead-free solder joints are achieved at the laser soldering parameters of 11 W, 20 mm/s or 8 W, 10 mm/s. The speed of laser soldering is improved dramatically based on scanning galvanometers. The mechanical properties of micro-joints are compared for different soldering methods, including continuous-wave (CW) fiber laser soldering, pulsed fiber laser soldering and infrared reflow soldering. The results indicate that CW fiber laser soldering can obviously improve the tensile strength of the joints with SnAg3.0Cu0.5 solder. In addition, the tensile strengths of SnAg3.0Cu0.5 solder and Sn63Pb37 solder soldered by CW fiber laser are compared. The mechanical property of SnAg3.0Cu0.5 is observed to be outstanding. The microstructure of fracture surfaces indicates that the fracture mechanism is ductility fracture. The metallographic structure of the solder joints is also investigated. It is found that the structure of soldering seam is fine and the interface is flat. The generated intermetallic compounds layer is Cu6Sn5.