Transient current profiles, measured while applying voltage pulses to W/TiN/Ti metal lines, showed two different stages. In the first stage, the transient current decreased due to both structural changes associated with Ti/W diffusion and the positive temperature coefficient of resistance of polycrystalline W/TiN/Ti. In the second stage, the transient current remained approximately constant due to the effect of morphological and microstructural changes counter-balanced by the thermal expansion of W near the melting temperature and the latent heat of fusion of W. Asymmetric electromigration and symmetric thermomigration fluxes resulted in the asymmetric metal line failure location near the anode. (C) 2012 Elsevier B.V. All rights reserved.