Assessing The Impact On Temperature Cycling Reliability Of High Levels Of Voiding In BGA Solder Joints
Authors: Grace Qin, Ph.D., Lei Nie, Ph.D., Francis Toth Jr, Raiyo Aspandiar, Ph.D., and Ian Williams Company: Intel Corporation Date Published: 10/14/2012
Abstract: The presence of process voids in Ball Grid Array (BGA) solder joints after Surface Mount Technology (SMT) reflow soldering process is perceived as a major quality issue in the electronic industry. Current industry standards (J-STD-001E and IPC-A-610E) require the BGA voids cumulative percentage area should be less than 25% after board assembly. However, the debate on whether excessive voids in BGA solder joints reduce their reliability margin still rages on in the industry. In this paper, a group of board assembled BGA packages, with 7% population of their solder joints containing a high level of voiding (>25%), were subjected to accelerated temperature cycling tests. A control group of board assembled BGAs, with small levels of voiding (mean value is about 1%) was also subjected to the same temperature cycling test. Test results revealed that the reliability of BGA solder joints with the excessive level of voids had lower reliability when compared to that of control group. Failure analysis provided further evidence that the failure mode of BGAs with big voiding was different from the controlled BGAs, and the cracks that led to the failures propagated through large voids in the solder joints.