雷达用片式电阻器件激光钎焊技术研究

A Study on the Laser Soldering Technologies of Radar Rectangular Chip Resistors

片式电阻器件在雷达阵面微波组件中应用广泛,文中采用激光钎焊的方法在印刷电路基板上进行片式电阻器件的焊接,得到了表面光亮、无氧化、成型良好的焊点,经对焊点力学性能、显微组织、断口形貌进行分析,得到的研究结论为:激光钎焊片式电阻器件焊点接头成型性好,其焊点力学性能明显优于红外再流焊焊点。激光钎焊获得的钎料/基体的显微组织可以比红外再流焊更加优异,焊点强度显著提高。观察、分析焊点的微观形貌,断裂处呈现明显的韧窝状态,这说明了激光钎焊焊点具有很强的塑变能力。

Rectangular chip resistors are widely used in microwave modules of radar,laser soldering process of rectangular chip resistors on PCB(printed circuit board)substrates was studied to obtain bright-surfaced,non-oxidation and good-forming solder joints in the paper.Mechanical properties,microstructures as well as shapes and appearance of the fractures were studied in details in this paper.The results show that laser soldering of chip resistors can gain well-formed solder joints with much better mechanical properties compared to the IR reflow soldering process.In addition,better microstructures of solder/substrate are also achieved by laser soldering system.Therefore,the soldering strength is improved significantly.Typical shear elongation dimples on the fracture after laser soldering can be found through observation and analysis of fracture morphologies,which indicates the excellent plastic property of the solder joints.