Research on the Mechanism of Assembly Stress on Solder Joint Fatigue Life of Large Size FCBGA Package

Heatsinks are indispensable in the field of electronic package, and the thermal dissipation requirements of component are increasing year by year. To enhance the thermal efficiency, it is general required that heatsinks fix the component with higher compressive force. High pressure implies the potential to affect the reliability of ball grid array (BGA) solder joints. This paper focuses on a large size flip chip ball grid array (FCBGA) package and verifies the feasibility of predicting the fatigue life of solder joints under compressive load and temperature cycle conditions through experiments and numerical methods. It also investigates the impact of typical and new types of heatsinks on the temperature cycle reliability of solder joints. In addition to this, corresponding analyses have been conducted on factors such as the material of the compression fixture and the pretension force of assembly.