Method and apparatus for electroplating a semiconductor wafer

Abstract

A method, apparatus and anode for plating copper or other metals onto a barrier or seed layer of a wafer surface is described. A copper layer of uniform thickness is plated on the surface by, for instance, maintaining a constant current density between the anode and wafer surface. Several configurations of anodes are described for obtaining the constant current density.

1 - 9 . (canceled)  
     
     
         10 . An apparatus for electroplating a wafer comprising: 
 a conductive clamp for engaging the periphery of a wafer; and    an anode disposed above the wafer, comprising a plurality of conductive elements disposed in an insulative member, the conductive elements being coupled to at least one source of potential.    
     
     
         11 . The apparatus of  claim 10 , wherein the conductive elements comprise a plurality of rods having a uniform density in the insulative member.  
     
     
         12 . The apparatus of  claim 10 , wherein the conductive elements comprise a plurality of rods having a higher density in a center of the anode when compared to a distance away from the center of the anode.  
     
     
         13 . The apparatus of  claim 10 , wherein the conductive elements include a plurality of concentric, annular members.  
     
     
         14 . The apparatus of  claim 10 , wherein a plurality of voltages are applied to the conductive elements with a higher voltage being applied to conductive elements disposed at a center of the anode, when compared to conductive elements disposed at a distance away from the center of the anode.  
     
     
         15 . The apparatus of  claim 10 , wherein the conductive elements comprise copper.  
     
     
         16 . The apparatus of  claim 11 , wherein the conductive elements comprise copper.  
     
     
         17 . The apparatus of  claim 12 , wherein the conductive elements comprise copper.  
     
     
         18 . The apparatus of  claim 13 , wherein the conductive elements comprise copper.  
     
     
         19 . The apparatus of  claim 14 , wherein the conductive elements comprise copper.  
     
     
         20 . An apparatus for electroplating a wafer comprising: 
 a conductive clamp disposed about the periphery of the electrode,    a lenticular shaped anode disposed above a surface of the wafer such that the anode is closer to the wafer at a center of the wafer when compared to the periphery of the wafer.    
     
     
         21 . The apparatus of  claim 20 , wherein the anode is copper.  
     
     
         22 . An apparatus for electroplating a wafer comprising: 
 an electrode disposed about the periphery of the wafer;    a cell having an inlet and an outlet facing a surface of the wafer, the cell carrying an electroplating fluid and being movable such that the outlet of the cell, sweeps over substantially the entire surface of the wafer;    an anode disposed within the cell; and    a source of potential applied between the electrode and the anode.    
     
     
         23 . The apparatus of  claim 22 , wherein the source of potential is varied as the cell moves.  
     
     
         24 . The apparatus of  claim 23 , wherein the rate at which the cell moves is varied.