Investigation on Copper Electrodeposition

Feng Qiao

In the recent years, copper has been replacing aluminum to be widely used as the interconnect material in the production of integrated circuit (IC) chips and other components used in microelectronic semiconductor devices. The copper interconnects are usually fabricated using a damascene electrochemical deposition process from an acidic electrolyte (termed plating bath) containing cupric sulfate (CuSO4) as well as several organic and inorganic constituents. A copper electrodeposition process suitable for routine integrated circuit (IC) manufacturing must deliver copper films that can reproducibly fill deep and narrow features (vias and trenches) without any voids or seams. This can be realized by adding to the plating bath small quantities of selected inorganic and organic additives which lead to the copper electrodeposition preferentially occurring at the bottom of the feature, known...