Life time prediction of anisotropic conductive adhesive joints during temperature cycling for electronics interconnect

A theoretical model for lifetime prediction of anisotropic conductive adhesive joints during temperature cycling is developed. The model is simple and elegant in the way that it only needs data from two resistance measurements and yet is able to predict the total cyclic life to failure. One of the resistance values chosen is at zero cycles, before the testing, and the other one can be chosen at any given number of temperature cycles. This implies that one can perform a limited number of test cycles and can therefore save a lot of testing time. The model is based on the hypothesis that the anisotropic conductive joint can be treated as a pressure sensitive Holm contact and that the conductivity of the contact is a function of the pressure on the contact point. Finally, the model is based on the fact that a crack is formed during the cycling. The resistance of the joint increases as a function of the increasing crack length and the crack length in turn is a function of the number of cycles.