We report a two‐step process for producing high‐conductance customized copper interconnections utilizing a localized electrodeposition process induced by Joule heat at a constriction. An initial metal interconnection is made by localized decomposition of an organometallic film using a focused laser beam. The conductance of such an initial interconnection can be low, but is enough to induce localized copper deposition by passing an ac current through the entire line in a copper‐containing electrolyte. The interconnections produced by this process are solid, continuous, and highly conducting.