Selective chemical-mechanical polishing properties of a cross-linked polymer and specific applications therefor

Abstract

The present invention is directed, in general, to a method of polishing a surface on substrates, such as semiconductor wafers and, more specifically, to a polishing pad suitable for this purpose. The polishing pad comprises a polishing body that includes a cross-linked polymer material, and may be incorporated into a polishing apparatus. Polishing includes positioning the substrate containing at least one layer against the polishing body and polishing the layer.

1 - 27 . (canceled)  
     
     
         28 . A polishing apparatus comprising: 
 a mechanically driven carrier head;    a polishing platen, said carrier head being positionable against said polishing platen to impart a polishing force against said polishing platen; and    a polishing pad attached to said polishing platen and including a polishing body comprising a cross-linked polymer comprising a cross-linked polymer having a hardness ranging from about 34 Shore A to about 60 Shore A and.    
     
     
         29 . The polishing apparatus as recited in claim  1 , wherein said cross-linked polymer is a thermoplastic foam.  
     
     
         30 . The polishing apparatus as recited in claim  1 , wherein said cross-linked polymer has a closed cell structure.  
     
     
         31 . The polishing apparatus as recited in claim  1 , wherein said cross-linked polymer is polyethylene.  
     
     
         32 . The polishing apparatus as recited in claim  1 , wherein said cross-linked polymer is a polyethylene having a closed cell structure.  
     
     
         33 . The polishing apparatus as recited in claim  1 , wherein said polishing body includes a base pad and said cross-linked polymer forms a polishing surface located over said base pad.  
     
     
         34 . The polishing apparatus as recited in claim  1 , wherein said polishing body has a Copper removal rate of at least about 3,300 Angstroms per minute.  
     
     
         35 . The polishing apparatus as recited in claim  1 , wherein said polishing body has a Tantalum removal rate ranging from about 75 to 175 Angstroms per two minutes.  
     
     
         36 . The polishing apparatus as recited in claim  1 , wherein said polishing body has a selectivity of Cu to Ta removal rates of greater than about 27:1.  
     
     
         37 . The polishing apparatus as recited in claim  1 , wherein a range of depths of copper from a wafer surface removed by said polishing body is within about 1250 Angstroms.