Effect of Heating Power On BGA Thermal Shock Reliability for a Fanout Package

The reliability of Fanout package with a ball grid array (BGA) for micro-system is studied under thermal shock. Different heat source powers are applied to the silicon substrate to imitate the power dissipation induced heat of power devices and the thermal fatigue life of the package are studied using the Anand constitutive model and Darveaux life model. The finite element method (FEM) simulation results show that the thermal fatigue life is not positively correlated with the heat source power. In a certain power range, the life first increases and then decreases. To explain this abnormal phenomenon, the fatigue analysis of solder balls with different heating power (10~55W) is carried out. The results show that in the low temperature stage, with the increase of the heat source power, the heat source offsets the low temperature effect to a certain extent, and the stress value of the solder balls decreases. And during the high temperature stage, the stress of the ball is hardly affected. However, with the increase of the heat source power, the thermal deformation of the structure is gradually serious, the effect of offsetting the low temperature effect is reduced, and the thermal fatigue life increases with the increase of the heat source power. The results of the paper can be useful for micro-system package design.