A detailed numerical study was made of the electromigration-induced shape changes of quasi 2-dimensional (cylindrical) voids in metallic thin films. The problem was treated within a continuum formulation that took account of mass transport along surfaces, current-crowding and a crystalline anisotropy of the surface mobility. Finite strips with periodic boundary conditions in the current direction were treated, as well as voids in infinite or semi-infinite films. In the case of the strip geometry, it was shown that linear instability of the strip edge could cause the release of voids into the interior of the film. Edge voids developed into fatal slits only in the presence of moderate crystalline anisotropy. Distorted voids in an infinite film typically disintegrated, but the break-up behaviour was qualitatively different in isotropic and anisotropic media. A rigid boundary attracted voids and could also induce void break-up.

Electromigration-Driven Shape Evolution of Two-Dimensional Voids. M.Schimschak, J.Krug: Journal of Applied Physics, 2000, 87[2], 695-703