Membrane-mediated electropolishing of damascene copper

Membrane-mediated electropolishing is a new process whereby a metal substrate is anodically oxidized in de-ionized water and the metal ions migrate across a charge-selective membrane to the cathode. All metal ions removed from the substrate are plated onto the cathode. In contrast with both CMP and electrochemical mechanical polishing the substrate is never exposed to abrasives or electrolytes, no reagents are consumed, no waste is generated and no post-cleaning is required. High removal rates and planarization efficiencies are achieved with low mechanical forces.