Finite Element Modelling and Life Prediction of Solder Joints of Board Level Devices Under Power Cyclic Load

During the operation of board-level electronic products, power cycling and on/off transitions lead to significant alternating stress loads and high-temperature cycling on the board-level solder joints. This, in turn, severely impacts the reliability and service life of the products during stable operation. To delve into the effects of power cycling loads on the solder joints of board-level electronic products, this paper establishes a finite element model integrating thermo-mechanical coupling, obtaining the temperature-strain distribution of solder joints through simulations. Utilizing the Engelmaier model of plastic deformation, the thermal fatigue life of solder joints in board-level electronic products is predicted. Simultaneously, the paper discusses the impact of different component layouts on temperature-strain distributions and the predicted life of solder joints. The results indicate that under cyclic power load, the lifetime of solder joints is influenced by the combined effects of power cycling and component layout. Smaller component spacing correlates with higher average solder joint temperatures, with the high-temperature zone closer to the board center, while the average strain distribution shows the opposite trend. The predicted lifetime of solder joints is closely related to the distribution of temperature and strain, and as the component spacing increases, the solder joint lifetime initially increases and then decreases, suggesting an optimal layout.