Effects of System Design on Fatigue Life of Solder Joints in BGA Packages Under Vibration at Random Frequencies

Fatigue life predictions for ball grid arrays (BGA) in electronic devices under random vibration have been made using the finite element method (FEM). Three different circuit board configurations were investigated to determine the best system design for longer fatigue lifetime. Moreover, to reveal the effect of the input frequency, different acceleration power spectral density (PSD) values were applied to the systems. The root-mean-square peeling stress was selected as the failure indicator. FEM results showed that the maximum peeling stress occurred at the outermost corners of solder joints adjacent to the printed circuit board in BGA packages. It was also found that, with increase in the input PSD, solder joints in BGA packages were more exposed to failure. Furthermore, it was revealed that the location of different parts of the system on the board can influence the stress distribution. The results show that a system with a heat sink at the corner of the board, away from the BGA packages, showed the longest fatigue life among the designed configurations.