A novel accelerated test technique for assessment of mechanical reliability of solder interconnects

New generations of lead-free solder interconnects are widely used in consumer electronics. Reliability of the devices which are subjected to rough handling, depends on the fracture resistance of the solder interconnects to shock and mechanical loading. The conventional reliability testing procedures are reported to be expensive and time consuming. Thus alternative tests and evaluation methods for reliability assessment of solder joints are required. In this study a new method for quality assessment of solder interconnects under high strain vibrational shear loading is presented using an ultrasonic fatigue testing system in combination with a special experimental set-up. Using this technique lifetime curves for solder ball bonds of two different Sn–Ag–Cu lead-free alloys were obtained. Failure mechanisms of the solder ball bonds were studied using SEM methods and the reliability curves were discussed with regard to the failure modes and the composition of the lead-free alloys. The applicability of the proposed method is discussed with regard to the literature data.