Abstract
Due to the End-of-Life Vehicles, car electronics must be Pb-free starting in 2016. Since the operation environment of these electronics changes with the mounted location, an understanding of the degradation behavior of the Pb-free solder joint is essential to ensuring long-term reliability. As such, this study focused on examining the degradation behavior and the dependence of the shear strength and crack length on the thermal cycling number under cabin (−40 to +85°C, 1500 cycles) and engine (−40 to +125°C, 3000 cycles) room conditions. We measured the shear strength and crack propagation length of R2012 and R3216 ceramic chip resistors as a function of thermal cycling number, and analyzed the degradation behavior with chip component size under two thermal cycling conditions. These results revealed that degradation occurs faster under engine room conditions than under cabin conditions. After 2500 thermal cycles, the crack length of the solder joint and the shear strength propagated to at least 95% and decreased by 78% compared to the as-reflowed bonding length and strength, respectively.
