Selective growth of copper for advanced metallization

Abstract

A novel and improved method of fabricating an integrated circuit, in which special copper films are formed by a combination of physical vapor deposition (PVD), chemical mechanical polish (CMP) and electrochemical copper deposition (ECD) techniques. The methods of the present invention make efficient use of several process steps resulting in less processing time, lower costs and higher device reliability. By these techniques, high aspect ratio trenches can be filled with copper without the problem of dishing. A special, selective electrochemical deposition (ECD) of copper metal is utilized taking place only on the seed layer in the trench. This auto-plating or “plate-up” occurs only in the trench and provides good sealing around the trench perimeter and fine copper metal coverage of the trench for subsequent robust interconnects. The selective plating of copper provides a robust copper film that is easily removed by subsequent chemical mechanical polish (CMP) and tends to be more uniform and free of the usual defects associated with CMP films.