Evolution of surface morphology of Au conductor lines under high-density electric current was studied by scanning tunneling microscopy. The loss of conductivity of thin Au films was found to occur through formation of voids resulted from electromigration followed by the depletion of the material. It was shown that the density of electric current passing through thin conducting films greatly affected their lifetime. Fractal analysis was employed to estimate numerically changes of surface topography of Au films. The fractal dimension was shown to be an optimum pre-fracture criterion for thin metal films under applying electric current.

Fractal Analysis of Electromigration-Induced Changes of Surface Topography in Au Conductor Lines. A.Panin, A.Shugurov, J.Schreiber: Surface Science, 2003, 524[1-3], 191-8