Constriction‐Induced Local Electrodeposition: The Principle of Self‐Induced Repair

Abstract

A fundamental study of the self‐induced repair (SIR) of constrictions is presented. SIR is a local electrodeposition process induced by the Joule heating at a constriction, together with the temperature dependence of the equilibrium potential at a metal‐electrolyte interface. Based on a one‐dimensional heat‐conduction model, a general equation for the maximum temperature rise at a constriction is obtained. An analysis based on thermodynamics and a series of experiments show a substantial temperature dependence of the equilibrium electrode potential of the Cu/Cu2+ interface. The rate of electrodeposition is then estimated using the Butler‐Volmer equation. The evolution of constrictions during the SIR process is studied with numerical simulation. It is predicted that with a local temperature rise of 50 K, the deposition rate can be as high as 2 μm per min, which is verified by a series of experiments. The results of theory and experiment show that the SIR process is self‐locating and self‐terminating. Electrical testing shows that the SIR process is able to eliminate the electrical symptoms of the constrictions completely. Scanning electron microscopy study shows that the electrodeposited copper has a dense and continuous texture. The use of the SIR process for repairing complete opens and making customized interconnections is also discussed.