Solder joint reliability of a thin small outline package (TSOP)

The reliability of 0.5 mm pitch, 32-pin thin small outline package (TSOP) solder joints was studied by experimental temperature cycling and a cost-effective 3D nonlinear finite element analysis. Temperature cycling results were presented as a Weibull distribution, and an acceleration factor was established for predicting the failure rate at operating conditions. The thermal fatigue life of the corner solder joints was estimated based on the calculated plastic strain the Coffin-Manson law, and isothermal fatigue data on solders. A correlation between the experimental and analytical results was also made. Failure analysis of the solder joints was performed using scanning electron microscopy and an optical method. A quantitative comparison between the Type-I and Type-II TSOP solder joints is presented