Apparatus for electroprocessing a substrate with edge profile control

Abstract

Embodiments of the invention generally provide methods and apparatuses for electroprocessing a substrate. In one embodiment, an apparatus for electrochemically processing the substrate includes a conductive processing surface adapted for processing a substrate thereon, and a polishing head for retaining the substrate against the processing surface. At least one drive mechanism provides relative motion between the conductive processing surface and the substrate. A first electrode is disposed below the conductive processing surface and is comprised of a first material. A second electrode is disposed radially inward of the first electrode and comprised of a second material.

1 . An apparatus for electrochemically processing a substrate, comprising: 
 a conductive processing surface adapted for processing the substrate thereon;    a polishing head for retaining the substrate against the processing surface;    at least one drive mechanism providing relative motion between the conductive processing surface and the substrate; and    a first electrode disposed below the conductive processing surface and comprised of a first material and a second electrode disposed radially inward of the first electrode and comprised of a second material.    
   
   
       2 . The apparatus of  claim 1 , further comprising a third electrode disposed radially inward of the second electrode, wherein the third electrode has a width greater than the first or the second electrode.  
   
   
       3 . The apparatus of  claim 1  further comprising: 
 a power source having a plurality of independently controllable outputs coupled to the first electrode and the second electrode.    
   
   
       4 . The apparatus of  claim 1 , further comprising: 
 a subpad disposed between the processing surface and the electrodes.    
   
   
       5 . The apparatus of  claim 1 , wherein the first electrode is coated with an inert material.  
   
   
       6 . The apparatus of  claim 5 , wherein the inert material has a thickness of at least 1 micron.  
   
   
       7 . The apparatus of  claim 5 , wherein the inert material has a thickness of at least less than 20 microns.  
   
   
       8 . The apparatus of  claim 5 , wherein the inert material is platinum.  
   
   
       9 . The apparatus of  claim 5 , wherein the inert material is adapted to reduce contamination by preventing corrosion of a body of the first electrode in contact with an electrolyte.  
   
   
       10 . The apparatus of  claim 1 , wherein the first electrode further comprises a platinum coated titanium body.  
   
   
       11 . The apparatus of  claim 1 , wherein the first material contains carbon or graphite.  
   
   
       12 . The apparatus of  claim 1 , wherein the first material contains titanium.  
   
   
       13 . The apparatus of  claim 1 , wherein the second material contains stainless steel.