Electrogenerated chemical polishing of copper

• We proposed a new polishing method which could realize stress free polishing.
• A theoretical model is proposed for evaluating the polishing solution.
• Roughness of a Cu surface is reduced from 100.5 nm to 3.6 nm.
• A patterned Cu surface with array of micro-column is planarized.

Stress free polishing method is preferred for a damage free surface of copper with ultra-flatness and ultra-smoothness. Such a surface offers a perfect substrate for integrated circuits and micro-electromechanical systems fabrication. A new polishing method, called electrogenerated chemical polishing (EGCP), is proposed based on the principle of the scanning electrochemical microscope (SECM) and the diffusion controlled chemical reaction. Roughness of a Cu surface is reduced from 100.5 nm to 3.6 nm by the proposed method. To demonstrate the planarization capability of this new method, a patterned Cu surface with an array of micro-columns is planarized with a peak-valley (PV) value from 4.7 μm to 0.059 μm.