Characterization of Degradation of 65nm Node via Chains and Single Vias

We used the resistance increase of single via to determine the intrinsic degradation kinetics of via in the temperature range 175 to 325C. The evolution of resistance in time follows a parabolic regime up to 325C, with activation energy of 1.0eV. It is worth noting that the evolution of degradation kinetics with temperature follows a simple Arrhenius equation. Thus, there is no evidence for an effect of thermo elastic stress on the degradation kinetics. We showed that the degradation mechanism in chains and single vias is similar. It is also noticeable that we found a bimodal distribution of resistance increase that is not visible from measurement of via chains. Together with making FA easier, this demonstrates the benefit of using single via to characterize stress voiding.