Investigations of the healing of electromigration-induced open-circuit failed submicron Al(0.5%Cu) interconnects were performed using in situ transmission electron microscopy (TEM). The samples consisted of 4000 Å thick Al (0.5%Cu) patterned over a TEM-transparent window into five runners in parallel, with linewidths 0.2, 0.3, 0.5, 0.8, and 1.0 μm. A novel sample design minimized any Joule heating in the runners. Our approach has allowed us to observe voids form, grow, migrate, fail a runner, and heal all with respect to the detailed local microstructure of the runners. In this letter, we focus on our time-resolved observations of the mechanisms of healing. © 1997 American Institute of Physics.