Electrolyte/organic additive separation in electroplating processes

Abstract

A method and apparatus for plating metals, such as copper, on a substrate. The apparatus generally includes a plating cell having an anolyte compartment containing an anolyte and a catolyte compartment containing a catolyte, an anode disposed in the anolyte compartment, and a dialysis membrane disposed between the anolyte compartment and the catolyte compartment, wherein the membrane screens molecules by molecular weight. The method generally includes supplying an electrolyte solution to a copper plating cell, plating copper onto a substrate in the plating cell from the electrolyte solution, and preventing the passage of additives from a catolyte compartment to an anolyte compartment with an anode disposed therein by providing a dialysis membrane between the anolyte compartment and catolyte compartment that is selective to molecule size.

1 . A copper plating system, comprising: 
 a plating cell having an anolyte compartment and a catolyte compartment;    an anode disposed in the anolyte compartment; and    a dialysis membrane disposed between the anolyte compartment and the catolyte compartment, wherein the dialysis membrane screens molecules by molecular weight.    
     
     
         2 . The copper plating system of  claim 1 , further comprising disposing a catolyte in the catolyte compartment having copper sulfate, sulfuric acid, copper chloride, and organic additives.  
     
     
         3 . The copper plating system of  claim 1 , further comprising disposing an anolyte in the anolyte compartment having copper sulfate, sulfuric acid, and copper chloride.  
     
     
         4 . The copper plating system of  claim 1 , wherein the dialysis membrane has a molecular weight cutoff of about 100.  
     
     
         5 . The copper plating system of  claim 1 , wherein the dialysis membrane is configured to prevent the passage of organic additives therethrough.  
     
     
         6 . The copper plating system of  claim 1 , wherein the dialysis membrane is configured to prevent the passage of suppressors and levelers therethrough.  
     
     
         7 . The copper plating system of  claim 1 , wherein the dialysis membrane has a molecular weight cutoff of about 1000.  
     
     
         8 . The copper plating system of  claim 1 , wherein a catolyte and an anolyte disposed in the plating cell have substantially equivalent concentrations of copper, acid, and chloride.  
     
     
         9 . The copper plating system of  claim 1 , wherein the dialysis membrane is disposed a distance away from the anode greater than about 0.1 mm.  
     
     
         10 . A method for plating copper, comprising: 
 supplying an electrolyte solution to a copper plating cell;    plating copper onto a substrate in the plating cell from the electrolyte solution;    supplying additives the electrolyte solution contained in a catolyte compartment disposed in the copper plating cell; and    preventing the passage of molecules based on their molecular weight from a catolyte compartment to an anolyte compartment with an anode disposed therein.    
     
     
         11 . The method of  claim 10 , wherein the preventing the passage of molecules includes providing a dialysis membrane between the anolyte compartment and the catolyte compartment.  
     
     
         12 . The method of  claim 11 , wherein the dialysis membrane has a molecular weight cutoff of about 1000.  
     
     
         13 . The method of  claim 11 , wherein the dialysis membrane has a molecular weight cutoff of about 100 or less.  
     
     
         14 . The method of  claim 11 , wherein the dialysis membrane has a molecular weight cutoff of about 160 or less.  
     
     
         15 . The method of  claim 10 , wherein the electrolyte solution comprises copper sulfate, sulfuric acid, and copper chloride.  
     
     
         16 . The method of  claim 11 , wherein the dialysis membrane has a distance from the anode of greater than about 0.1 mm.  
     
     
         17 . The method of  claim 10 , wherein the anolyte and catolyte have essentially the same copper concentration.  
     
     
         18 . A copper plating system, comprising: 
 a plating cell having an anolyte compartment containing an anolyte and a catolyte compartment containing a catolyte;    an anode disposed in the anolyte compartment; and    a dialysis membrane disposed between the anolyte compartment and the catolyte compartment, wherein the membrane is selective to molecules having a molecular weight greater than about 80.    
     
     
         19 . The method of  claim 18 , wherein the dialysis membrane is selective to molecules having a molecular weight greater than about 150.  
     
     
         20 . The method of  claim 18 , wherein the dialysis membrane is selective to molecules having a molecular weight greater than about 1000.  
     
     
         21 . A method for plating copper, comprising: 
 supplying an electrolyte solution to a copper plating cell;    plating copper onto a substrate in the plating cell from the electrolyte solution; and    preventing the passage of molecules having a molecular weight greater than about 100 between a catolyte compartment and an anolyte compartment with an anode disposed therein.    
     
     
         22 . A filtering device for use in a copper plating system, comprising a dialysis membrane configured to prevent the passage of organic additives therethrough, wherein the dialysis membrane has a molecular weight cutoff of about 100.