Scanning probe studies of electromigration in 4‐&mgr;m‐wide by 1‐&mgr;m‐thick electroplated Au wires reveal changes in surface morphology. Features that develop on a submicrometer length scale were observed using current densities up to 7.5×106A/cm2and temperatures up to 280 °C for time intervals ranging from a few minutes up to a few days. Scanning probe images of thesamearea taken before, during, and after current stressing reveal substantial changes in surface morphology. Both hillock growth and void formation have been observedinsitu. Changes in surface morphology caused by electromigration can be quantitatively described from the scanning probe images and new techniques for studying mass flow due to electromigration are now possible.