Effect of External Mechanical Structure of BGA Package on Solder Joint Reliability

In practical application of Ball Grid Array (BGA), temperature changes usually cause solder joint degradation, leading to the crack even final failure of BGA. Using external means to reduce the fatigue life consumption of BGA with temperature variations is of substantial value. In this current study, three-dimensional (3D) numerical models of board level BGA packages were developed with three different strain suppressing methods. In order to investigate the effects of various techniques on solder joint thermal fatigue life, a series of thermal cycle simulations and the corresponding analyses were conducted through the 3D models, and the fatigue life of the solder joint is estimated according to the strain. It is found that specific actions must be taken to control the strain in board-parallel direction as well as the warpage of board or package. Insights from this work provide a better understanding of the effects of external mechanical structures on Printed Circuit Boards (PCBs) with the BGA package, and the modeling method additionally provide tools and guidance for analyzing and enhancing such thermal reliability of BGA.