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

This paper reports on an experimental study on how thermal cycling aging ex posure changes the solder joint microstructure, intermetallic layer thickne ss and the residual shear strength and fatigue life in a single plastic hal l grid array (PBGA) solder joint specimen. In this study, a single EGA sold er joint specimen was specially designed to evaluate the microstructure and mechanical properties of three different batches of solder joint after sub jected to 0, 500, 1000, and 2000 cycles of thermal cycling aging (-40 degre esC to 125 degreesC). It is important to relate the effects of thermal cycl ing aging on the changes of the microstructural and intermetallic layer thi ckness to the residual shear strength and fatigue life of solder joints sub jected to thermal cycling aging exposure. The results of this study shows t hat the microstructural and intermetallic development due to thermal cyclin g 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.