Thermal cycling aging effects on microstructural and mechanical properties of a single PBGA solder joint specimen

This paper reports on an experimental study on how thermal cycling aging exposure changes the solder joint microstructure, intermetallic layer thickness and the residual shear strength and fatigue life in a single plastic ball grid array (PBGA) solder joint specimen. The single BGA solder joint specimen was specially designed to evaluate the microstructure and mechanical properties of three different batches of solder joint after subjected to 0, 500, 1000, and 2000 cycles of thermal cycling aging (-40°C to 125°C). It is important to relate the effects of thermal cycling aging on the changes of the microstructural and intermetallic layer thickness to the residual shear strength and fatigue life of solder joints subjected to thermal cycling aging exposure. The results of this study shows that the microstructural and intermetallic development due to thermal cycling aging has a major impact on the residual mechanical and fatigue strength of the solder joint. It was noted that the solder joint shear strength and residual fatigue life degrades with exposure to thermal cycling aging