On the thermo-mechanical risk assessment of complex Printed Circuit Boards (PCB) by finite element modelling and warpage measurements

Thermo-mechanically induced stresses and strains are one of the key concerns in the reliability assessment of electronic components as they cause material fatigue, cracks, and fractures in the solder joints as the most prominent failure modes. The stresses in the interconnects between the electronic components and the printed circuit boards (PCB) are dominated by the behaviour of these two rigid partners [1], whereby the PCBs are highly complex structures in themselves consisting of several layers and various materials. Knowing the thermo-mechanical behaviour of the PCB as well as of the electronic components would allow estimating the reliability prospects based on numerical simulations, in which mechanical parameters like stress concentrations and accumulated equivalent creep strains are computed. The latter is usually used as failure criterion for low cycle solder fatigue at the interconnects [2]. Within the work presented in this paper, we aimed to establish a detai led representation of printed circuit board (PCB) by means of finite element method (FEM). A modelling approach considering multilayer PCBs based on the commercial software ABAQUS is shown and compared to an already exiting approach given by ANSYS. Finally, both approaches are compared to experimental warpage measurements.