Method and apparatus for acid and additive breakdown removal from copper electrodeposition bath

Abstract

A method and apparatus for removing waste material from a plating solution is disclosed. The invention generally provides a plating cell having an electrolyte inlet and an electrolyte drain, an electrolyte storage unit in fluid communication with the electrolyte inlet, and a diffusion dialysis chamber in fluid communication with the electrolyte drain and the electrolyte storage unit. The diffusion dialysis chamber is generally configured to receive at least a portion of used electrolyte solution and remove waste material therefrom in order to provide a refreshed electrolyte solution to the electrolyte storage unit. A method generally includes supplying an electrolyte solution to a copper plating cell, plating copper onto a substrate in the plating cell with the electrolyte solution, removing used electrolyte solution from the plating cell, and refreshing a portion of the used electrolyte solution with a diffusion dialysis device.

1 . An electrochemical plating system, comprising: 
 a plating cell; and    a diffusion dialysis device in fluid communication with the plating cell, the diffusion dialysis device configured to remove waste material from an electrolyte solution.    
     
     
         2 . The plating system of  claim 1 , wherein the diffusion dialysis device comprises alternating diluted acid cells and electrolyte cells separated by anionic membranes, the electrolyte cells passing the electrolyte solution therethrough and the diluted acid cells removing the waste material.  
     
     
         3 . The plating system of  claim 2 , wherein the anionic membrane comprises a matrix having a positive charge inside and a selected porosity for selectively passing acids and at least some organic molecules.  
     
     
         4 . The diffusion dialysis device of  claim 2 , wherein the pore size of the anionic membrane is between 50 and 100 angstroms.  
     
     
         5 . The plating system of  claim 2 , wherein the anionic membranes allow negatively charged ions and at least some waste material within the electrolyte solution to diffuse therethrough into the diluted acid cells.  
     
     
         6 . The plating system of  claim 2 , wherein the waste material comprises organic additive breakdown product.  
     
     
         7 . The plating system of  claim 2 , wherein the anionic membranes are more permeable to accelerator and its breakdown products than leveler and its breakdown products and less permeable to suppressor and its breakdown products.  
     
     
         8 . The plating system of  claim 2 , wherein the anionic membranes prevent positively charged copper ions from passing therethrough.  
     
     
         9 . The plating system of  claim 2 , wherein the diffusion dialysis devise comprises between about 25 and about 100 total collective electrolyte cells and diluted acid cells.  
     
     
         10 . The plating system of  claim 1 , wherein the plating cell is divided into a catholyte compartment and an anolyte compartment by a cation membrane, the catholyte compartment for circulating the electrolyte solution therethrough.  
     
     
         11 . The system of  claim 1 , further comprising an electrodialysis cell that receives the electrolyte solution from the diffusion dialysis device.  
     
     
         12 . The system of  claim 11 , wherein the electrodialysis cell comprises at least one cationic membrane between cells having an electrolyte solution containing waste material and cells having a refreshed electrolyte solution.  
     
     
         13 . The plating system of  claim 1 , further comprising an electrolyte storage unit.  
     
     
         14 . A diffusion dialysis device for extracting waste material from an electrolyte solution, comprising: 
 a housing having a plurality of anionic membranes positioned therein to define alternating electrolyte cells and diluted acid cells; and    a deionized water loop comprising: 
 a supply conduit that supplies a controlled concentration of acid to the diluted acid cells; and  
 a return conduit that receives an outflow from the diluted acid cells.  
   
     
     
         15 . The diffusion dialysis device of  claim 14 , wherein each anionic membrane comprises a matrix having a positive charge inside and a selected porosity to extract waste material comprising organic breakdown product and acid.  
     
     
         16 . The diffusion dialysis device of  claim 15 , wherein the anionic membranes allow negatively charged ions and at least some of the waste material within the electrolyte solution to diffuse therethrough into the diluted acid cells.  
     
     
         17 . The plating system of  claim 15 , wherein the anionic membranes are more permeable to accelerator and its breakdown products than leveler and its breakdown products and less permeable to suppressor and its breakdown products.  
     
     
         18 . The diffusion dialysis device of  claim 15 , wherein the anionic membranes prevent positively charged copper ions from passing therethrough.  
     
     
         19 . The diffusion dialysis device of  claim 15 , wherein the pore size of the anionic membranes is between 50 and 100 angstroms.  
     
     
         20 . A method for plating copper, comprising: 
 supplying an electrolyte solution to a plating cell;    plating onto a substrate in the plating cell with the electrolyte solution;    removing used electrolyte solution from the plating cell; and    refreshing a portion of the used electrolyte solution with a diffusion dialysis device.    
     
     
         21 . The method of  claim 20 , wherein the refreshing a portion of the used electrolyte with the diffusion dialysis devise comprises: 
 receiving the used electrolyte solution in an electrolyte cell of the diffusion dialysis device;    urging negative sulfate ions and organic additive breakdown waste material through an anionic membrane into a diluted acid cell; and    removing a refreshed electrolyte solution from the electrolyte cell.    
     
     
         22 . The method of  claim 21 , wherein urging comprises maintaining a concentration gradient across the electrolyte cell and the diluted acid cell.  
     
     
         23 . The method of  claim 20 , further comprising receiving the refreshed electrolyte solution in an electrodialysis cell that removes additional organic additives and organic additive breakdown products from the refreshed electrolyte solution.  
     
     
         24 . The method of  claim 20 , wherein the plating cell is divided into a catholyte compartment and an anolyte compartment by a cation membrane, the catholyte compartment for circulating the electrolyte solution therethrough.  
     
     
         25 . A method for replenishing a copper plating solution, comprising: 
 receiving a portion of a used electrolyte solution in an electrolyte cell of a diffusion dialysis device;    urging negatively charged sulfate ions and organic additive breakdown waste material into a diluted acid cell adjacent the electrolyte cell to provide a refreshed electrolyte solution, wherein the diluted acid cell and the electrolyte cell are separated by an anionic membrane; and    returning the refreshed electrolyte solution to the copper plating solution.    
     
     
         26 . The method of  claim 25 , wherein urging comprises maintaining a concentration gradient across the electrolyte cell and the diluted acid cell.  
     
     
         27 . The method of  claim 25 , wherein the receiving step comprises receiving the used electrolyte solution in up to 100 electrolyte cells within a single diffusion dialysis device.  
     
     
         28 . The method of  claim 25 , wherein a collective total of the electrolyte cells and the diluted acid cells is between about 25 and about 100.