Acceleration Reliability Tests for Lead-free Solder Joints under Thermal Cycling Coupling with Current Stressing

摘要

The lead-tin solder has already been replaced by the lead-free solders gradually in most industrial applications. However, the reliability of lead-free solder is still a critical problem that must be considered during the design scheme period of electronic product. In this paper, the feasibility of a thermo-electric accelerated test, as well as its corresponding failure mechanism, was discussed to reduce the reliability test duration. The test lifetime, analyzed with the Weibull distributions, revealed an apparently decreased time-to-failure and the cycles-to-failure in the thermo-electric accelerated test, comparing with the one under thermal cycling test. Based on the observation of the microstructure evolution in solder joints, it can be found that the electric current in the reliability test could accelerate the evolution of solder microstructure, without apparently changing the corresponding failure mechanism. Thus, it could be concluded that the thermo-electric test scheme would be a valuable option to achieve highly accelerated reliability test for electronic products.