Specialized structures have been developed to understand how interconnect and via would link together in a circuit to bring out the weakest link in the interconnect-via system. This article reports a phenomenon where electromigration occurred in an actual circuit with signal lines connected by individual vias. A prediction is made into the weak link in the via-Interconnect system based on real time product. In the interconnect-via system used, the TiW barrier blocked the material flow from M2 to Ml. W plugs would block the material flow as they do with the barrier layers and the failures would occur at the via to interconnect interface as noticed in this case. Depending on the electron flow through the via, the material will either accumulate at the via-interconnect interface, which will induce inter-metal dielectric cracks, or deplete, causing discontinuity (opens) of the interconnect lines.