Thermomechanical Fatigue Analysis of Pb-free Solder Joints

Creep and fatigue damage can accumulate due to the coefficient of thermal expansion (CTE) mismatch between different materials in devices during service life, eventually results in thermomechanical fatigue failure. For Pb-free solder joints, stress and strain concentration was located in the solder near the interface, where recrystallization accompanied with initiation and propagation of cracks. The stress and strain of the solder joints near the mounting hole were more concentrated, which will accelerate the occurrence of thermomechanical fatigue failure.