Electrochemical plating cell having a diffusion member

Abstract

Embodiments of the invention provide an electrochemical plating cell that is divided by an ionic membrane into an anolyte volume and a catholyte volume. The anolyte volume of the plating cell includes an electrically resistive diffusion member and an anode positioned therein. The catholyte volume of the cell is generally configured to receive a substrate for plating.

1 . An electrochemical plating cell, comprising: 
 a fluid basin having a fluid inlet and a fluid outlet;    a membrane positioned across the fluid basin, the membrane separating the fluid basin into a catholyte volume and an anolyte volume;    an anode positioned in the anolyte volume; and    an electrically resistive fluid permeable diffusion member positioned across the anolyte volume.    
   
   
       2 . The plating cell of  claim 1 , wherein the membrane comprises a cationic membrane.  
   
   
       3 . The plating cell of  claim 2 , wherein the diffusion member comprises a varying thickness disk shaped member.  
   
   
       4 . The plating cell of  claim 3 , wherein the diffusion member comprises a porous ceramic disk.  
   
   
       5 . The plating cell of  claim 1 , wherein the diffusion member comprises a disk shaped member having a substantially uniform thickness.  
   
   
       6 . The plating cell of  claim 3 , wherein the diffusion member comprises a disk shaped member having a first thickness on a first edge of the disk shaped member and a second thickness on a second opposing edge of the disk shaped member, the first thickness being different from the second thickness.  
   
   
       7 . The plating cell of  claim 6 , wherein a central plane of the diffusion member is positioned substantially parallel to an upper surface of the anode.  
   
   
       8 . The plating cell of  claim 7 , wherein the membrane is positioned at an angle across the fluid basin with respect to the upper surface of the anode.  
   
   
       9 . The plating cell of  claim 8 , wherein the membrane is positioned at a first distance from the anode surface on a thin side of the diffusion member and at a second distance from the anode surface on a thick side of the diffusion member, the first distance being greater than the second distance.  
   
   
       10 . The plating cell of  claim 3 , wherein the diffusion member is positioned substantially parallel to an upper surface of the anode.  
   
   
       11 . An electrochemical plating cell, comprising: 
 a cell body defining a fluid processing volume and having an opening configured to receive a substrate for processing;    a cationic membrane positioned across the fluid processing volume and separating the fluid processing volume into a catholyte volume and an anolyte volume;    an anode positioned in the anolyte volume; and    an electrically insulative fluid permeable diffusion member positioned across the fluid processing volume between the anode and the cationic membrane.    
   
   
       12 . The plating cell of  claim 11 , wherein the cationic membrane is positioned parallel to an upper surface of the anode.  
   
   
       13 . The plating cell of  claim 11 , wherein the cationic membrane is positioned at an angle with respect to an upper surface of the anode.  
   
   
       14 . The plating cell of  claim 11 , wherein the diffusion member comprises a disk shaped member having a substantially uniform thickness.  
   
   
       15 . The plating cell of  claim 13 , wherein the diffusion member comprises a disk shaped member having a first thickness on a first edge and a second thickness on a second edge, the first thickness being greater than the second thickness.  
   
   
       16 . The plating cell of  claim 15 , wherein the cationic membrane is positioned a first distance from the anode at a position in the fluid processing volume adjacent the first side and a second distance from the anode at a position in the fluid processing volume adjacent the second side, wherein the first distance is less than the second distance.  
   
   
       17 . The plating cell of  claim 13 , wherein the angle is between about 5° and about 15°.  
   
   
       18 . The plating cell of  claim 11 , further comprising an anolyte fluid inlet and an anolyte fluid outlet in fluid communication with the anolyte volume, and a catholyte fluid inlet and a catholyte fluid outlet in fluid communication with the catholyte volume.  
   
   
       19 . The plating cell of  claim 18 , wherein the anolyte fluid inlet is positioned to deliver an anolyte solution to a volume below the diffusion member and to a volume above the diffusion member.  
   
   
       20 . An electrochemical plating cell, comprising: 
 a fluid basin having an opening configured to receive a substrate for processing;    a copper anode positioned in a lower portion of the fluid basin;    a porous electrically insulative diffusion member positioned across the fluid basin at a position between the anode and the opening;    a cationic membrane positioned across the fluid basin at a position between the diffusion member and the opening.    
   
   
       21 . The plating cell of  claim 20 , wherein the diffusion member is wedge shaped and has a central plane that is substantially parallel to an upper surface of the anode.  
   
   
       22 . The plating cell of  claim 21 , wherein the cationic membrane is positioned at a tilt angle with respect to the upper surface of the anode.  
   
   
       23 . The plating cell of  claim 22 , wherein the tilt angle is proportional to a slope of the diffusion member.  
   
   
       24 . The plating cell of  claim 20 , wherein the diffusion member is disk shaped member having a substantially uniform thickness.  
   
   
       25 . The plating cell of  claim 24 , wherein the cationic membrane is positioned parallel to the diffusion member.