Copper electrodeposition sequence for the filling of cobalt lined features

In one example, an electroplating system comprises a first bath reservoir, a second bath reservoir, a clamp, a first anode in the first bath reservoir, a second anode in the second bath reservoir, and a direct current power supply. The first bath reservoir contains a first electrolyte solution that includes an alkaline copper-complexed solution. The second bath reservoir contains a second electrolyte solution that includes an acidic copper plating solution. The direct current power supply generates a first direct current between the clamp and the first anode to electroplate a first copper layer on the cobalt layer of the wafer submerged in the first electrolyte solution. The direct current power supply then generates a second direct current between the clamp and the second anode to electroplate a second copper layer on the first copper layer of the wafer submerged in the second electrolyte solution.