片式微波组件激光软钎焊气密封装技术研究

文中对片式微波组件激光软钎焊气密封装工艺开展研究,优化了影响焊缝成形的焊接结构、热台温度、助焊剂、离焦量、激光功率、焊接速度等工艺参数,分析了激光软钎焊密封接头微观组织,测试了激光软钎焊密封组件的气密性。结果表明:激光软钎焊封盖过程是一个温度场不断变化的动态过程,因此激光功率和焊接速度两参数也应在一定范围内通过程序设计动态调节。钎料可完全填充壳体与盖板之间形成的间隙,钎料中无空洞和裂纹,钎料未溢流到壳体内部。钎料与镀Ni 层接触并润湿良好,在钎料与壳体和盖板界面未形成粗大脆性的金锡金属间化合物。接头上部钎料基本保持(Sn)+(Pb)共晶组织状态,接头下部镀Ni层与钎料之间形成薄且均匀连续的金属间化合物层AuSn和AuSn₂。采用优化后的工艺参数激光软钎焊密封的组件气密性满足机载有源天线阵面应用要求。

Research on Laser Soldering Technique for Hermtic Packaging of Tile Microwave Module

This paper focuses on the laser soldering technique for the hermetic packaging of the tile microwave module. The process parameters which influence the formation of the soldering joint, such as soldering structure, the temperature of the heating stage, soldering flux, defocus amount, laser power and soldering rate, are optimized. The microstructure of the laser soldering joint is analyzed. The hermeticity of the module is measured. The results show that while the temperature field during the process of the hermtic packaging using the laser soldering is dynamically changed, the laser power and soldering rate should change dynamically within limits by program design. The solder fills in the gap between the shell and lid. No void and crack is observed in the joint, while no solder is observed within the shell. The solder wets well on the Ni plating layer. No coarse brittle Au-Sn intermetallic compound forms in the interface between the solder and the shell or lid. The microstructure of the solder remains eutectic(Sn)+(Pb) near the surface of the joint. A thin AuSn and AuSn₂ intermetallic compound layer forms between the Ni-P plating layer and the solder near the internal surface of the joint. The hermticity of the module sealed using optimized laser soldering process meets the requirement of the active antenna array.