Study on short-circuit failure of solder-joint interconnections

To study the short-circuit failure on lead-free solder joints soldering with no cleaning flux after heat and humidity test(85°/85%RH) for several days, stereomicroscope and scanning electronic microscope(SEM) and energy spectrometer(EDS) are used to inspect the failure mode and phenomenon, further analyze the root cause of the short-circuit failure. The results showed that, the failure of short-cut between two solder joints was due to tin migration growth to contact each other under the effects of wet circumstance and direct current, tin migration was mainly related to the residual of no-cleaning flux.