Calculation of BGA contact resistance by using the contacts volume method

In Warsaw University of Technology was developed special BGA256r test specimen [1] for early failure detection during the reliability tests. The failures were detected by resistance measurement by four- point method. Before the reliability tests, the real, initial resistance values were measured. Proposed method of calculation BGA contacts initial resistance is useful for preparing FEA analysis, especially to define BGA contact geometry. The calculated values of some kinds of BGA contacts are presented. The measured values of BGA256r contacts are presented.