Multi-step polishing system and process of using same

Abstract

A multi-step polishing system, and a process for polishing a workpiece using the system. The system includes one or more polishing stations. The workpiece is polished in the presence of an oxidizer-free medium, and subsequently, the workpiece is polished in the presence of an oxidizing medium. This polishing sequence extends the life of the polishing pads and provides for a more uniform polish.

1 . A wafer polishing process comprising: 
 polishing a surface of a wafer in the presence of an oxidizer-free medium; and, subsequently,    polishing the surface of the wafer in the presence of an oxidizing medium.    
     
     
         2 . The wafer polishing process of  claim 1 , wherein said oxidizer-free medium comprises an oxidizer-free slurry, and said oxidizing medium comprises an oxidizing slurry.  
     
     
         3 . The wafer polishing process of  claim 1 , wherein said oxidizer-free medium comprises an oxidizer-free fluid, and said oxidizing medium comprises an oxidizing fluid.  
     
     
         4 . The wafer polishing process of  claim 1 , wherein said polishing in the presence of an oxidizer-free medium and said polishing in the presence of an oxidizing medium both occur at a first polishing station.  
     
     
         5 . The wafer polishing process of  claim 4 , further comprising, 
 transferring said wafer from said first polishing station to a second polishing station; and    polishing said surface of said wafer in the presence of an oxidizing medium at said second polishing station.    
     
     
         6 . The wafer polishing process of  claim 1 , wherein said polishing in the presence of an oxidizer-free medium occurs at a first polishing station and said polishing in the presence of an oxidizing medium occurs at a second polishing station.  
     
     
         7 . The wafer polishing process of  claim 1 , wherein said polishing in the presence of an oxidizer-free medium and said polishing in the presence of an oxidizing medium both comprise linear chemical-mechanical polishing.  
     
     
         8 . The wafer polishing process of  claim 1 , wherein said surface comprises a copper-containing component.  
     
     
         9 . The process of  claim 8 , wherein said oxidizing medium comprises at least one oxidizer capable of oxidizing at least a portion of said copper-containing component.  
     
     
         10 . A wafer polishing process comprising: 
 supplying an oxidizer-free medium to a polishing portion of a polishing station;    polishing a surface of a wafer in the presence of said oxidizer-free medium at said polishing station;    discontinuing the supply of said oxidizer-free medium to the polishing portion;    supplying an oxidizing medium to the polishing portion; and    polishing the surface of the wafer in the presence of said oxidizing medium at said polishing portion.    
     
     
         11 . The wafer polishing process of  claim 10 , wherein said surface comprises a copper-containing component.  
     
     
         12 . The wafer polishing process of  claim 10 , wherein said oxidizer-free medium comprises an oxidizer-free slurry, and said oxidizing medium comprises an oxidizing slurry.  
     
     
         13 . The wafer polishing process of  claim 10 , wherein said oxidizer-free medium comprises an oxidizer-free fluid, and said oxidizing medium comprises an oxidizing fluid.  
     
     
         14 . A wafer polishing process comprising: 
 chemically-mechanically polishing a copper-containing surface of a wafer in the presence of an oxidizer-free slurry at a first polishing station;    transferring the wafer from said first polishing station to a second polishing station; and    chemically-mechanically polishing the copper-containing surface of the wafer in the presence of an oxidizing slurry at said second polishing station.    
     
     
         15 . A wafer polishing system comprising: 
 a first chemical-mechanical polishing station having a polishing portion;    a source of an oxidizer-free medium in communication with said polishing portion; and    a source of an oxidizing medium in communication with said polishing portion.    
     
     
         16 . The wafer polishing system of  claim 15 , further comprising: 
 a second polishing station; and    a transfer mechanism adapted to move said wafer from said first polishing station to said second polishing station.    
     
     
         17 . A wafer polishing system comprising: 
 a first polishing station adapted to polish a surface of a wafer in the presence of an oxidizer-free medium;    a source of an oxidizer-free medium in communication with said first polishing station;    a second polishing station adapted to polish said surface of said wafer in the presence of an oxidizing medium;    a source of an oxidizing slurry in communication with said second polishing station; and    a transfer mechanism adapted to move a wafer from said first polishing station to said second polishing station.    
     
     
         18 . The wafer polishing system of  claim 17 , wherein said source of oxidizing solution is also in communication with said first polishing station.  
     
     
         19 . The wafer polishing system of  claim 17 , further comprising: 
 a second source of an oxidizing medium in communication with said first polishing station.    
     
     
         20 . The wafer polishing station of  claim 17 , wherein said oxidizer-free medium comprises an oxidizer-free slurry, and said oxidizing medium comprises an oxidizing slurry.