Electromigration-saturation experiments were carried out on passivated L-shaped interconnects which had 3 contacts, via W-filled vias at the ends and corners of the L. Currents of various magnitude and direction were independently applied to the 2 legs of the L. Variations in the steady-state electrical resistance were observed, and were attributed to variations in the location of voids along the lines. Variations were also observed in the rate of approach to the steady state, and were attributed to variations in void shape. The effects of electromigration in L-shaped interconnects were simulated by using an electromigration model which was based upon the 1-dimensional Korhonen-model; modified so as to include the effects of junctions. It was shown that, by using a single set of input parameters and void-shape information, the simulation could be used to make accurate worst-case predictions of steady-state electromigration-induced resistance changes in simple L-shaped interconnect trees.

Electromigration Saturation in a Simple Interconnect Tree. S.P.Hau-Riege, C.V.Thompson: Journal of Applied Physics, 2000, 88[5], 2382-5