Research of Vertical Line, Surface Printing and Reflow Soldering Process of Electronic Assemblies 3D Structure

In the field of electronic assembly, solder joints are usually located in the PCB plane. However, with the higher and higher demand of heat dissipation and signal shielding, the dispersion of device and pathways require the solder to extend in the three-dimensional structure, thus forming the solder joints of three-dimensional structure. During reflow soldering, solder on the vertical direction(Z axis) is affected by gravity. Especially in a continuous line or surface soldering, controlling the downward flow of solder is the key problem to ensure the quality. The analysis and experiments were conducted in the three aspects of properties of solder paste, printing and reflow process, which not only won the continuous uniform solder joint, but achieved the requirement of batch printing and single reflow. And also the number of thermal shock of the device was reduced.