Method and apparatus for simultaneously removing multiple conductive materials from microelectronic substrates

Abstract

A method and apparatus for simultaneously removing conductive materials from a microelectronic substrate. A method in accordance with one embodiment of the invention includes contacting a surface of a microelectronic substrate with an electrolytic liquid, the microelectronic substrate having first and second different conductive materials. The method can further include controlling a difference between a first open circuit potential of the first conducive material and a second open circuit potential of the second conductive material by selecting a pH of the electrolytic liquid. The method can further include simultaneously removing at least portions of the first and second conductive materials by passing a varying electrical signal through the electrolytic liquid and the conductive materials. Accordingly, the effects of galvanic interactions between the two conductive materials can be reduced and/or eliminated.

1 - 73 . (canceled)  
   
   
       74 . A method for processing a semiconductor substrate, comprising: 
 contacting a surface of the semiconductor substrate with an electrolytic liquid, the surface containing a first conductive material and a second conductive material different than the first conductive material;    selecting a pH of the electrolytic liquid to suppress or eliminate a galvanic reaction between the first and second conductive materials in the presence of the electrolytic liquid; and    passing a varying electrical signal through the electrolytic liquid and the first and second conductive materials while suppressing or eliminating the galvanic reaction.    
   
   
       75 . The method of  claim 74 , further comprising simultaneously removing at least portions of the first and second conductive materials while passing the varying electrical signal through the electrolytic liquid and the first and second conductive materials.  
   
   
       76 . The method of  claim 74  wherein selecting a pH of an electrolytic liquid includes selecting a pH of the electrolytic liquid based at least in part on compositions of the first and second conductive materials.  
   
   
       77 . The method of  claim 74  wherein the first conductive material includes tungsten and the second conductive material includes copper, further wherein reducing a galvanic reaction between the first and second conductive materials includes selecting a pH of the electrolytic liquid to be from about 2 to about 5.  
   
   
       78 . The method of  claim 77 , further comprising simultaneously removing at least portions of tungsten and copper while passing the varying electrical signal through the electrolytic liquid and the first and second conductive materials.  
   
   
       79 . The method of  claim 77 , further comprising removing at least portions of a conductive layer that includes at least 50% copper.  
   
   
       80 . The method of  claim 74  wherein the first conductive material includes tungsten and the second conductive material includes copper, further wherein reducing a galvanic reaction between the first and second conductive materials includes controlling the pH to be from about 2 to about 5.  
   
   
       81 . The method of  claim 74  wherein contacting the surface of the semiconductor substrate includes contacting the semiconductor substrate with an electrolytic liquid that includes at least one of an oxidizer, a corrosion inhibitor and a pH control agent.  
   
   
       82 . The method of  claim 74 , further comprising removing at least portions of the first and second conductive materials from the semiconductor substrate and changing a resistance of the electrolytic liquid as the first and second conductive materials are removed from the semiconductor substrate.  
   
   
       83 . The method of  claim 74 , further comprising removing at least portions of the first and second conductive materials from the semiconductor substrate and increasing a resistance of the electrolytic liquid as the first and second conductive materials are removed from the semiconductor substrate.  
   
   
       84 . The method of  claim 74 , further comprising contacting the semiconductor substrate with a polishing pad and moving at least one of the polishing pad and the semiconductor substrate relative to the other while passing the varying electrical signal through the electrolytic liquid and the first and second conductive materials.  
   
   
       85 . A method for processing a semiconductor substrate, comprising: 
 contacting the semiconductor substrate with an electrolytic liquid, the semiconductor substrate having a first conductive material and a second conductive material different than the first conductive material;    controlling a pH of the electrolytic liquid to suppress or eliminate the galvanic reaction between the first and second conductive materials in the presence of the electrolytic liquid; and    simultaneously removing at least portions of the first and second conductive materials from the semiconductor substrate while the galvanic reaction between the first and second conductive materials is suppressed or eliminated.    
   
   
       86 . The method of  claim 85  wherein the first conductive material includes at least one of tungsten and WN x  and the second conductive material includes copper, further wherein controlling a pH of the electrolytic liquid includes controlling a pH of the electrolytic liquid to be from about 2 to about 5.  
   
   
       87 . The method of  claim 85  wherein the first conductive material includes tungsten and the second conductive material includes copper, further wherein controlling a pH of the electrolytic liquid includes controlling a pH of the electrolytic liquid to be from about 2 to about 5, and wherein simultaneously removing at least portions of the first and second conductive materials includes passing a variable electrical current through the electrolytic liquid and the conductive materials while engaging a polishing pad with the semiconductor substrate and moving at least one of the semiconductor substrate and the polishing pad relative to the other while passing the electrical signal through the first and second conductive materials via two electrodes spaced apart from the semiconductor substrate.  
   
   
       88 . The method of  claim 87  wherein passing an electrical signal includes passing an electrical signal from a first electrode spaced apart from the semiconductor substrate, through the electrolytic liquid to the first and second conductive materials and through the electrolytic liquid to a second electrode spaced apart from the first electrode and spaced apart from the semiconductor substrate.  
   
   
       89 . The method of  claim 87  wherein passing an electrical signal includes passing an electrical signal from a first electrode spaced apart from the semiconductor substrate, through the electrolytic liquid to the first and second conductive materials and to a second electrode positioned in contact with the semiconductor substrate.  
   
   
       90 . The method of  claim 85  wherein simultaneously removing at least portions of the first and second conductive materials includes removing tungsten and copper.  
   
   
       91 . The method of  claim 85  wherein simultaneously removing at least portions of the first and second conductive materials includes removing the first conductive material at a first rate and removing the second material at a second rate different than the first rate.  
   
   
       92 . The method of  claim 85  wherein simultaneously removing the first conductive material and the second conductive material includes simultaneously removing a barrier layer material and a blanket fill material.  
   
   
       93 . A method for processing a semiconductor substrate having a tungsten containing portion and a copper containing portion, comprising: 
 selecting a pH of an electrolytic liquid based at least in part on compositions of the tungsten containing portion and the copper containing portion such that a galvanic reaction of the tungsten containing portion and the copper containing portion is suppressed in the presence of the electrolytic liquid;    contacting the semiconductor substrate with an electrolytic liquid having the selected pH; and    simultaneously removing at least part of the copper containing portion and the tungsten containing portion by passing a varying electrical signal through the electrolytic liquid and the copper containing and tungsten containing portions while the electrolytic liquid contacts the microelectronic substrate and while the galvanic reaction is suppressed or eliminated.    
   
   
       94 . The method of  claim 93  wherein removing at least part of the copper containing portion includes removing at least part of a conductive line or a conductive via, and wherein removing at least part of the tungsten containing portion includes removing at least part of a barrier layer.  
   
   
       95 . The method of  claim 93  wherein removing at least part of the copper containing portion includes removing at least part of a portion having about 50% or more copper.  
   
   
       96 . The method of  claim 93  wherein removing at least part of the tungsten containing portion includes removing at least part of a portion having WN x .  
   
   
       97 . The method of  claim 93  wherein simultaneously removing at least part of the copper containing portion and part of the tungsten containing portion includes removing at least part of the tungsten containing portion at a first rate and removing at least part of the copper containing portion at a second rate about four times greater than the first rate.  
   
   
       98 . The method of  claim 93 , further comprising contacting the microelectronic substrate with a polishing pad and moving at least one of the polishing pad and the microelectronic substrate relative to the other while simultaneously removing at least part of the copper containing portion and the tungsten containing portion.