Solder Joint Reliability of BGA Package under End-User Handling Test Conditions

Component level test methodologies to understand the reliability of package in end user handling conditions with cyclic bend and cyclic shock are presented in this paper. Displacement controlled cyclic bend tests conducted over a wide range of displacements are used to understand the behavior of solder joints at low strain rates. In cyclic shock, a new test method called "self cancelling shock pulse" is introduced that results in a single peak strain. This method enables a direct comparison with system level data as well as producing accurate cycles to failure. Board design improvements to obtain consistent failure modes are also discussed. Differences in performances of lead free solders in bend and shock tests are analyzed and explained through failure analysis and mechanisms. The testing results were compiled to create a board strain (E) versus number-of-cycles to failure (N) curve to validate these new methodologies and show their advantages and limitations with a potential as a new method for component testing and system design.