Copper electrodeposition sequence for the filling of cobalt lined features

Abstract

In one example, an electroplating system comprises a bath reservoir, an anode in the bath reservoir, and a direct-current power supply. The bath reservoir initially contains a first-electrolyte solution that includes an alkaline copper-complexed solution. The bath reservoir is arranged to be drained of the first-electrolyte solution and replaced with and contain a second-electrolyte solution. The second-electrolyte solution includes an acidic-copper plating solution. The direct-current power supply generates a first direct current between the clamp and the anode to electroplate a first copper layer on the cobalt layer of the substrate submerged in the first-electrolyte solution. The direct-current power supply then generates a second direct current between the clamp and the anode to electroplate a second copper layer on the first copper layer of the substrate submerged in the second electrolyte solution. Other systems and methods are also described.

What is claimed is: 
     
         1 . An electroplating system comprising:
 a bath reservoir configured to contain a first-electrolyte solution, the first-electrolyte solution comprising an alkaline copper-complexed solution, the bath reservoir is configured to be drained and replaced with and contain a second-electrolyte solution, the second-electrolyte solution comprising an acidic-copper plating solution;   a clamp to:
 hold a substrate and to submerge the substrate in the first-electrolyte solution comprising the alkaline copper-complexed solution; and 
 after the bath reservoir is drained of the first-electrolyte solution and replaced with and containing the second electrolyte solution comprising the acidic-copper plating solution, the clamp is further to submerge the substrate in the second-electrolyte solution, the substrate comprising at least some features deposited with a cobalt layer; and 
   an anode to be submerged in the first-electrolyte solution, the anode subsequently to be submerged in the second-electrolyte solution; and   a direct-current power supply to generate a first direct current between the clamp and the anode and configured to electroplate a first copper layer on the cobalt layer of the substrate in the first-electrolyte solution, the direct-current power supply is further to generate a second direct current between the clamp and the anode and configured to electroplate a second copper layer on the first copper layer of the substrate in the second-electrolyte solution.   
     
     
         2 . The electroplating system of  claim 1 , wherein the first copper layer includes a copper nucleation layer formed on top of the cobalt layer of the substrate. 
     
     
         3 . The electroplating system of  claim 2 , wherein the second copper layer includes a copper fill layer formed on top of the copper nucleation layer, the copper fill layer configured to fill the features of the substrate. 
     
     
         4 . The electroplating system of  claim 1 , wherein the substrate is pre-treated with a hydrogen-helium plasma treatment prior to being submerged in the first-electrolyte solution. 
     
     
         5 . The electroplating system of  claim 4 , wherein the hydrogen-helium plasma has a temperature between about 75 degrees Celsius and about 250 degrees Celsius. 
     
     
         6 . The electroplating system of  claim 4 , wherein the cobalt layer is deposited on the substrate via chemical vapor deposition prior to the hydrogen-helium plasma treatment. 
     
     
         7 . The electroplating system of  claim 1 , wherein the alkaline copper-complexed solution has a pH greater than about 9, and the acidic-copper plating solution has a pH less than about 2.