A method of fabricating a copper interconnect on a substrate is disclosed in which the interconnect and substrate are subjected to a low temperature anneal subsequent to polarization of the interconnect and prior to deposition of an overlying dielectric layer. The low temperature anneal inhibits the formation of hillocks in the copper material during subsequent high temperature deposition of the dielectric layer. Hillocks can protrude through passivation layer, thus causing shorts within the connections of the semiconductor devices formed on the substrate. In one example, the interconnect and substrate are annealed at a temperature of about 200° C. for a period of about 180 seconds in a forming gas environment comprising hydrogen (5 parts per hundred) and nitrogen (95 parts per hundred).