Methods for electroplating copper

Abstract

Embodiments of the invention are directed to methods of electroplating copper onto at least one surface of a substrate in which more uniform electrical double layers are formed adjacent to the at least one surface being electroplated (i.e., the cathode) and an anode of an electrochemical cell, respectively. In one embodiment, the electroplated copper may be substantially-free of dendrites, exhibit a high-degree of (111) crystallographic texture, and/or be electroplated at a high-deposition rate (e.g., about 6 μm per minute or more) by electroplating the copper under conditions in which a ratio of a cathode current density at the at least one surface to an anode current density at an anode is at least about 20. In another embodiment, a porous anodic film may be formed on a consumable copper anode using a long conditioning process that promotes forming a more uniform electrical double layer adjacent to the anode.

1 . A method, comprising:
 forming an electrochemical cell including at least one surface of a substrate, an anode, and an electroplating solution in contact with the at least one surface and the anode, wherein the electroplating solution includes at least one suppressor agent; and   electroplating copper onto the at least one surface under conditions in which a ratio of a cathode current density at the at least one surface to an anode current density at the anode is at least about 20.   
     
     
         2 . The method of  claim 1  wherein electroplating copper onto the at least one surface under conditions in which a ratio of a cathode current density at the surface to an anode current density at the anode is at least about 20 comprises electroplating the copper onto the at least one surface under conditions in which the ratio is about 20 to about 100. 
     
     
         3 . The method of  claim 1  wherein electroplating copper onto the at least one surface under conditions in which a ratio of a cathode current density at the surface to an anode current density at the anode is at least about 20 comprises electroplating the copper onto the at least one surface under conditions in which the ratio is about 40 to about 100. 
     
     
         4 . The method of  claim 1  wherein electroplating copper onto the at least one surface under conditions in which a ratio of a cathode current density at the surface to an anode current density at the anode is at least about 20 comprises electroplating the copper onto the at least one surface under conditions in which the ratio is about 60 to about 100. 
     
     
         5 . The method of  claim 1  wherein electroplating copper onto the at least one surface under conditions in which a ratio of a cathode current density at the surface to an anode current density at the anode is at least about 20 comprises:
 selecting a strength and a concentration of the at least one suppressor agent, and a surface area of the anode so that the ratio is established during the act of electroplating copper.   
     
     
         6 . The method of  claim 1  wherein:
 the anode comprises an inert anode; and   electroplating copper onto the at least one surface comprises electroplating the copper from dissolved copper in the electroplating solution.   
     
     
         7 . The method of  claim 1  wherein:
 the anode comprises a copper-containing anode; and   electroplating copper onto the at least one surface comprises electroplating the copper provided from the copper-containing anode.   
     
     
         8 . The method of  claim 1  wherein the anode comprises a copper-containing anode. 
     
     
         9 . The method of  claim 8  wherein the copper-containing anode comprises:
 a porous mass of copper particles;   a grooved body comprising copper;   a porous mass of sintered copper-containing particles; or   a mesh comprising copper.   
     
     
         10 . The method of  claim 1  wherein electroplating copper comprises applying a generally constant voltage between the anode and the at least one surface of the substrate. 
     
     
         11 . The method of  claim 1  wherein electroplating copper comprises applying a time-varying voltage between the anode and the at least one surface of the substrate. 
     
     
         12 . The method of  claim 1  wherein forming an electrochemical cell including at least one surface of a substrate, an anode, and an electroplating solution in contact with the at least one surface and the anode comprises forming the electrochemical cell to include the at least one surface, the anode, and the electroplating solution having dissolved copper therein present in a concentration from about 50 grams per liter to about 100 grams per liter. 
     
     
         13 . The method of  claim 1  wherein the at least one suppressor agent of the electroplating solution comprises one or more of the following suppressor agents:
 a surfactant;   a chelating agent;   a leveler agent; and   a wetting agent.   
     
     
         14 . The method of  claim 1  wherein the electroplating solution comprises at least one accelerator agent. 
     
     
         15 . The method of  claim 14  wherein the at least one accelerator agent is substantially free of at least one type of alkali element. 
     
     
         16 . The method of  claim 1 , further comprising linearly oscillating the substrate in the electroplating solution during the act of electroplating copper. 
     
     
         17 . The method of  claim 1 , further comprising rotating the substrate in the electroplating solution during the act of electroplating copper. 
     
     
         18 . The method of  claim 1 , further comprising orienting the at least one surface of the substrate in a downwardly facing direction. 
     
     
         19 . The method of  claim 1  wherein electroplating copper comprises depositing the copper onto the at least one surface of the substrate as a substantially dendrite-free film at a deposition rate of at least about 6 μm per minute. 
     
     
         20 . The method of  claim 1  wherein the at least one suppressor agent provides a suppression strength of at least about 5.0. 
     
     
         21 . The method of  claim 1  wherein forming an electrochemical cell including at least one surface of a substrate, an anode, and an electroplating solution in contact with the at least one surface and the anode comprises immersing the substrate in the electroplating solution. 
     
     
         22 . A method, comprising:
 forming an electrochemical cell including a cathode, a consumable copper-containing anode, and an electroplating solution in contact with the cathode and the consumable copper-containing anode; and   forming a porous anodic film on the consumable copper-containing anode by generating a current through the electrochemical cell for a time sufficient to pass at least about 1000 coulombs per liter of the electroplating solution through the electroplating solution.   
     
     
         23 . The method of  claim 22 :
 wherein the cathode comprises a conditioning cathode; and   further comprising:
 replacing the conditioning cathode with at least one surface of a substrate; and 
 electroplating copper provided from the consumable copper-containing anode onto the at least one surface of the substrate. 
   
     
     
         24 . The method of  claim 23  wherein electroplating copper comprises applying a generally constant voltage between the consumable copper-containing anode and the at least one surface of the substrate. 
     
     
         25 . The method of  claim 23  wherein electroplating copper comprises applying a time-varying voltage between the consumable copper-containing anode and the at least one surface of the substrate. 
     
     
         26 . The method of  claim 22   wherein the electrochemical cell comprises a conditioning electrochemical cell; and   further comprising:
 forming a separate electroplating electrochemical cell including the consumable copper-containing anode having the porous anodic film and at least one surface of a substrate; and 
 electroplating copper provided from the consumable copper-containing anode having the porous anodic film onto the at least one surface. 
   
     
     
         27 . The method of  claim 26  wherein electroplating copper comprises applying a generally constant voltage between the consumable copper-containing anode and the at least one surface of the substrate. 
     
     
         28 . The method of  claim 26  wherein electroplating copper comprises applying a time-varying voltage between the consumable copper-containing anode and the at least one surface of the substrate. 
     
     
         29 . The method of  claim 22  wherein the consumable copper-containing anode is configured as a plate comprising copper. 
     
     
         30 . The method of  claim 22  wherein the electroplating solution comprises at least one suppressor agent. 
     
     
         31 . The method of  claim 30  wherein the at least one suppressor agent of the electroplating solution comprises one or more of the following suppressor agents:
 a surfactant;   a chelating agent;   a leveler agent; and   a wetting agent.   
     
     
         32 . The method of  claim 22  wherein the electroplating solution comprises at least one accelerator agent. 
     
     
         33 . The method of  claim 32  wherein the at least one accelerator agent is substantially free of at least one type of alkali element. 
     
     
         34 . The method of  claim 22  wherein the porous anodic film of the consumable copper-containing anode comprises one or more of the following: copper oxide, copper chloride, and copper phosphide.