A new method to evaluate BGA pad cratering in lead-free soldering

Pad cratering is one of the most important issues in lead- free soldering. The PCB materials change and the increased reflow temperature account for the degradation of the drop test performance of the PCB materials. This paper uses both finite element analysis (FEA) and experimental testing to study PCB pad lift and adhesion. The pad lift force in pull and shear tests has been determined with the test data, and a new cratering test using ball shear test was proposed for qualifying PCB BGA pads incorporating multiple reflows and mechanical loading.