The Test Method And Equipment For Anti-Shock Performance Of Solder Joints

The trend of portable electronic products such as cellular phones, PDAs, and MP3 players being widely used and the transition from lead-containing to lead-free solder alloys have brought serious reliability issues for solder interconnects under dynamic loading conditions, such as drop impact test, in which lead-free solder joints can be particularly susceptible to brittle fracture failure at the solder pad interface.The electronic packaging industry is looking for a test method to evaluate the impact reliability of solder joints.By the results of many researches , not only the instrument but also the method exist many limitations in the standards and test measures of anti-shock performance of solder joints . In this situation, the instrument to test anti-shock performance of solder joints was conducted on the base of the research work solder interface.In this thesis, the influence of heating factor(Qη), defined as the integral of the measured temperature over the dwell time above liquidus in the reflow profile on impact toughness of solder joints was evaluated quantitatively by means of high speed shear testing and conventional shear test, in which the shear rate was 1.5m/s and 8×10-5m/s respectively. The results of high speed shear testing indicate that with heating factor increasing, the impact toughness of solder joints increases to a peak and then decreases. Therefore, it is obvious that Qη=800～1100 s°C is an optimal heating factor range for Sn3.5AgCu, in which the assembly exhibits the greatest impact toughness under high speed shear testing. The results also show that the failure mode and position of solder joints in these two tests are quite different, and the results of high speed shear testing appears more susceptible to the reflow process than that of the static shear testing.In this thesis, the process of high shear test and the effect of the shear angles were simulated .The result of simulation indicated that there are strong relations between the high shear test and drop test for the failure of solder joints are same on these tests. The simulated results also showed that the solder was easier brittle fail when the shear angle is 45 degree.