Influence of soldering residual stress on modal characteristics of printed circuit board assembly

Inhalt:
Reflow soldering process, as a key step in the processing of the printed circuit board components, determines the final quality and reliability of the components. The residual stress induced by the soldering process is closely related to the modal characteristics of PCBA (Printed Circuit Board Assembly). This paper uses ANSYS workbench code to build a numerical model to analyse the influence of soldering residual stress in infrared hot air reflow soldering process on the modal characteristics of the PCBA. Firstly, the thermal-stress field simulation model of the PCBA during the soldering process is built and the two residual stress of the BGA solder joint within different time after the soldering process is obtained, respectively. Then, the two different residual stress of the PCBA is introduced in the modal model by applying the pre-stress technology. Finally, the modal model of the PCBA with the residual stress is performed and first sixth order modes of the PCBA is present. The modal characteristic of the PCBA with different residual stress is compared. It is shown that the residual stress induced by the soldering process has significant influencing on the PCBA modal characteristics. The research results provide a valuable reference for the PCBA soldering process design and reliability design.