Method and apparatus for local polishing control

Abstract

A method and apparatus for local polishing and deposition control in a process cell is generally provided. In one embodiment, an apparatus for electrochemically processing a substrate is provided that selectively polishes discrete conductive portions of a substrate by controlling an electrical bias profile across a processing area, thereby controlling processing rates between two or more conductive portions of the substrate.

1 . A polishing pad comprising: 
 one or more anodes formed in the polishing pad at or near a polishing surface of the polishing pad; and    one or more cathodes formed in the polishing pad at or near the polishing surface of the polishing pad and electrically isolated from the one or more anodes.    
     
     
         2 . The polishing pad of  claim 1 , further including non-conducting elements formed in the polishing pad to provide the electrical isolation between the one or more anodes and the one or more cathodes.  
     
     
         3 . The polishing pad of  claim 1 , further including a wiring network connected to the one or more anodes and the one or more cathodes.  
     
     
         4 . The polishing pad of  claim 3 , further including: 
 an electrical connector electrically connected to the wiring network and adapted to maintain electrical contact with the wiring network when the polishing pad is in motion.    
     
     
         5 . The polishing pad of  claim 4 , further including: 
 a current source electrically connected to the electrical connector and adapted to provide a current to the one or more anodes and the one or more cathodes through the electrical connector and the wiring network.    
     
     
         6 . The polishing pad of  claim 1 , further including one or more grooves formed in the polishing surface of the polishing pad.  
     
     
         7 . The polishing pad of  claim 1 , further including a transparent window.  
     
     
         8 . A method of using a chemical mechanical polishing (CMP) tool to perform electrochemical mechanical polishing (ECMP) of a substrate having metal formed thereon, the method comprising: 
 providing a polishing pad having one or more anodes formed in the polishing pad at or near a polishing surface of the polishing pad, and one or wore cathodes formed in the polishing pad at or near the polishing surface of the polishing pad and electrically isolated from the one or more anodes;    introducing an electrolytic polishing fluid between the substrate and the polishing surface so as to establish an electrical circuit between the one or more anodes, the metal, and the one or more cathodes;    providing a current to the one or more anodes and the one or more cathodes to cause electrochemical migration of metal ions from the metal into the electrolytic polishing solution; and    pressing the substrate against the polishing surface while moving at least one of the polishing pad and the substrate.    
     
     
         9 . The method of  claim 8 , wherein moving at least one of the polishing pad and the wafer includes rotating at least one of the polishing pad and the substrate.  
     
     
         10 . The method of  claim 8 , wherein the current is proportional to a removal rate of metal, and including providing different amounts of current to select anodes and cathodes to vary the removal rate of metal over the metal layer.