超大规模集成电路铜互连电镀工艺（Copper interconnect plating process for very large scale integrated circuit）.doc

超大规模集成电路铜互连电镀工艺（Copper interconnect plating process for very large scale integrated circuit） 1. double embedded copper interconnect process With the continuous improvement of chip integration, copper has replaced aluminum as the mainstream interconnect technology in VLSI manufacturing. As an alternative to aluminum, copper wires can reduce interconnect impedance, reduce power and cost, and improve chip integration, device density, and clock frequency. Because of the copper etching is very difficult, so the copper interconnect using dual Damascene technology, also called Double Technology (Dual Damascene), Damascus 1) first deposited a thin layer of silicon nitride (Si3N4) as a diffusion barrier layer and etching termination layer, 2) then in the silicon oxide deposited on a certain thickness (SiO2), 3 then the micro hole) lithography (Via), 4) on the through hole part etching, 5) after a trench lithography (Trench), 6) to complete etched vias and trenches, 7) followed by sputtering (PVD) diffusion barrier layer (TaN/Ta) and copper seed layer (Seed Layer). The role of Ta is to enhance the adhesion of Cu and the seed layer is used as a conductive layer plating, 8) after the plating process is the copper interconnects, 9) is the final annealing and chemical mechanical polishing (CMP), flattened processing and cleaning of copper coating. Electroplating is the main process to complete copper interconnect. The copper plating process of integrated circuit usually adopts electroplating solution of sulfate system. The bath is composed of cupric sulfate, sulfuric acid and water, which is light blue. When the power is added between the copper (anode) and the silicon (cathode), the solution generates an electric current and forms an electric field. The anode copper reacts into copper ions and electrons, and the cathode also reacts with formation deposited on the silicon surface of copper ions and electrons near the cathode, copper ions under the influence of the electric field