Polishing pad for chemical mechanical polishing

Abstract

The present invention provides in one embodiment, a polishing pad 100 for chemical mechanical polishing. The polishing pad comprises a polishing body 110 . The polishing body comprises a thermoplastic foam substrate 115 having a surface 120 comprising concave cells 125 . A polishing agent 130 coats an interior surface 135 of the concave cells. The polishing agent comprises an inorganic metal oxide that includes carbides or nitrides. Yet another embodiment of the present invention is a method for preparing a polishing pad 200.

1 . A polishing pad for chemical mechanical polishing comprising: 
 a polishing body comprising a thermoplastic foam substrate having a surface comprising concave cells; and    a polishing agent coating an interior surface of said concave cells, wherein said polishing agent comprises an inorganic metal oxide that includes carbides or nitrides.    
     
     
         2 . The polishing pad as recited in  claim 1 , wherein said carbides or nitrides are incorporated into a lattice of said inorganic metal oxides.  
     
     
         3 . The polishing pad as recited in  claim 2 , wherein said nitrides comprise silicon nitrides or titanium nitrides.  
     
     
         4 . The polishing pad as recited in  claim 2 , wherein said carbides include silicon carbides or titanium carbides.  
     
     
         5 . The polishing pad as recited in  claim 4 , wherein said lattice of said inorganic metal oxides comprise silicon oxide or titanium oxide.  
     
     
         6 . The polishing pad as recited in  claim 1 , wherein said inorganic metal oxide comprise silicon carbides and silicon nitrides.  
     
     
         7 . The polishing pad as recited in  claim 1 , wherein said nitrides comprise about 10 mol percent of said polishing agent.  
     
     
         8 . The polishing pad as recited in  claim 1 , wherein said carbides comprise about 10 mol percent of said polishing agent.  
     
     
         9 . The polishing pad as recited in  claim 1 , wherein said polishing agent has a oxygen to silicon ratio of at least about 8:1.  
     
     
         10 . The polishing pad as recited in  claim 1 , wherein said polishing pad has a hardness of about 60 KPa or greater.  
     
     
         11 . The polishing pad as recited in  claim 1 , wherein said polishing pad has an elastic modulus of greater than about 3 MPa.  
     
     
         12 . The polishing pad as recited in  claim 1 , wherein said polishing pad has an loss modulus of about 0.4 MPa or greater.  
     
     
         13 . A method for preparing a polishing pad for chemical mechanical polishing, comprising: 
 exposing closed cells within a thermoplastic foam substrate to provide a substrate surface comprising concave cells; and    coating an interior surface of said concave cells with a polishing agent comprising an inorganic metal oxide, wherein carbides and nitrides are incorporated into said inorganic metal oxide during said coating.    
     
     
         14 . The method as recited in  claim 13 , wherein coating comprises: 
 exposing said substrate surface to an initial plasma reactant in a plasma enhanced chemical vapor deposition (PECVD) process to produce a modified surface thereon; and    exposing said modified surface to a secondary plasma reactant in said PECVD process to form said polishing agent.    
     
     
         15 . The method as recited in  claim 14 , wherein said initial plasma reactant comprises argon or helium, and exposure to said initial plasma proceeds for about 30 seconds.  
     
     
         16 . The method as recited in  claim 14 , wherein exposure to a secondary plasma reactant proceeds for at least about 30 minutes.  
     
     
         17 . The method as recited in  claim 14 , wherein exposure to a secondary plasma reactant proceeds for between about 30 minutes and about 60 minutes.  
     
     
         18 . The method as recited in  claim 14 , wherein said secondary plasma reactant comprises tetraethoxy silane or titanium alkoxide.  
     
     
         19 . The method as recited in  claim 14 , wherein an interior of said closed cells comprise nitrogen gas and said nitrogen gas reacts with said secondary plasma reactant to form said nitride.  
     
     
         20 . The method as recited in  claim 14 , wherein said thermoplastic foam substrate reacts with said secondary plasma reactant to form said carbide.