Abstract: A process for controlling grain growth in the microstructure of thin metal films (e.g., copper or gold) deposited onto a substrate. In one embodiment, the metal film is deposited onto the substrate to form a film having a fine-grained microstructure. The film is heated in a temperature range of 70-100° C. for at least five minutes, wherein the fine-grained microstructure is converted into a stable large-grained microstructure. In another embodiment, the plated film is stored, after the step of depositing, at a temperature not greater than −20° C., wherein the fine-grained microstructure is stabilized without grain growth for the entire storage period.