A detailed investigation of the failure formation of copper trace cracks during drop tests

The development cycle of new products can be dramatically reduced if exact lifetime models are at hand. This requires the precise knowledge of the failure modes and the failure position under all test and service conditions. In case of dynamic mechanical loads like drops of BGA modules, broken copper traces at the PCB side are more and more often observed to be the ultimate failure effect. However, straightforward FEM simulations have shown unrealistic high stress and strain results not matching experimental observations which prove that a realistic representation of this failure is not trivial.