Fixed abrasive polishing pad

Abstract

Apparatuses and methods are disclosed using a fixed abrasive polishing pad to perform mechanical polishing of a surface. The apparatus includes a polishing pad positioned opposing a wafer support to provide for polishing of a surface of a wafer placed on the support. The polishing pad includes a first member having a first polishing surface formed from an abrasive first material that is structurally degradable during polishing. The polishing pad also includes a second member having a second polishing surface formed from a second material that is less degradable and less abrasive relative to said first material. The first and second polishing surfaces define a polishing face that is brought into contact with the surface to be polished. Preferably, a portion of the second member can be removed from the polishing pad so that the first polishing surface extends beyond the second polishing surface to provide for a fixed amount of abrasion using the first member prior to the second member contacting the surface and substantially reducing or stopping the polishing process.

What is claimed is:  
     
         1 . A polishing pad comprising: 
 a first member comprising a structurally degradable abrasive first material; and,    a second member comprising a second material that is less degradable and less abrasive than said first material.    
     
     
         2 . The pad of  claim 1 , wherein said first member includes a portion that extends beyond said second member.  
     
     
         3 . The pad of  claim 1 , wherein: 
 said first member includes a first polishing surface; and,    said second member includes a second polishing surface that with said first polishing surface define a polishing face.    
     
     
         4 . The pad of  claim 1 , wherein: 
 said first member includes a plurality of first sections having first polishing surfaces; and,    said second member includes a plurality of second sections having second polishing surfaces that with said first polishing surfaces define a polishing face.    
     
     
         5 . The pad of  claim 4 , wherein said plurality of first and second sections are provided in an alternating arrangement.  
     
     
         6 . The pad of  claim 1 , wherein: 
 said second material is more soluble in a solvent than said first material.    
     
     
         7 . The pad of  claim 6 , wherein: 
 said second material comprises an acrylate polymer; and,    said first material comprises a urethane material containing discrete abrasive particles ranging from 15 nm-1000 nm is size and selected from the group consisting of SiO 2 , CeO 2 , Al 2 O 3 , Ta 2 O 5 , and MnO 2 .    
     
     
         8 . The pad of  claim 1 , wherein said first material comprises a matrix material containing discrete particles that are more abrasive than said matrix.  
     
     
         9 . The pad of  claim 8 , wherein said discrete particles are selected from the group consisting of SiO 2 , CeO 2 , Al 2 O 3 , Ta 2 O 5 , and MnO 2 .  
     
     
         10 . The pad of  claim 8 , wherein said matrix material is substantially nonabrasive.  
     
     
         11 . The pad of  claim 8 , wherein said matrix material is abrasive.  
     
     
         12 . The pad of  claim 1 , wherein said second material is substantially nonabrasive.  
     
     
         13 . The pad of  claim 12 , wherein said second material is substantially nondegradable.  
     
     
         14 . The pad of  claim 1 , wherein said second material is substantially nondegradable.  
     
     
         15 . The pad of  claim 1 , wherein said first member comprises a chemically active material.  
     
     
         16 . A polishing pad for use in performing chemical mechanical polishing, comprising: 
 a first member including a plurality of first sections having first polishing surfaces and comprising a first material further comprising an erodible, substantially nonabrasive matrix material containing discrete particles of abrasive material distributed therein; and,    a second member including a plurality of second sections having second polishing surface and comprising a second material that is less erodible and less abrasive than said first material, wherein said first and second polishing surfaces define a polishing face and said second member is removable to allow a portion of said first member containing said first polishing surface to extend beyond said second polishing surface.    
     
     
         17 . The pad of  claim 16 , wherein said first and second members are formed with said first polishing surface extending beyond said second polishing surface.  
     
     
         18 . The pad of  claim 16 , wherein said second material comprises a soluble acrylate polymer.  
     
     
         19 . The pad of  claim 18 , wherein said soluble acrylate polymer is soluble in HCl/H 2 O solutions.  
     
     
         20 . The pad of  claim 18 , wherein said soluble acrylate polymer is soluble in a solvent selected from the group consisting of acetone and isopropyl alcohol.  
     
     
         21 . The pad of  claim 18 , wherein said soluble acrylate polymer comprises polymethylmethacrylate.  
     
     
         22 . The pad of  claim 16 , wherein said first material comprises a material selected from the group consisting of urethanes and polyphenyl oxide, and containing discrete abrasive particles ranging from 15 nm-1000 nm in size and selected from the group consisting of SiO 2 , CeO 2 , Al 2 O 3 , Ta 2 O 5 , and MnO 2 .  
     
     
         23 . An apparatus for performing mechanical polishing of a semiconductor wafer surface, comprising: 
 a polishing pad having a polishing face, wherein said polishing pad further comprises, 
 a first member having a first polishing surface and comprising a structurally degradable abrasive first material, and,  
 a second member having a second polishing surface and comprising a second material that is less degradable and less abrasive than said first material, wherein said first and second polishing surfaces define said polishing face;  
   a wafer support having a support surface, said wafer support being disposed opposite to said pad, such that said polishing face and said support surface are substantially parallel and can be brought within close proximity; and,    a motor connected to provide relative motion between said polishing face and said support surface.    
     
     
         24 . The apparatus of  claim 23 , wherein said first member includes a portion including said first polishing surface that extends beyond said second polishing surface.  
     
     
         25  The apparatus of  claim 23 , wherein said motor includes, 
 a support motor to impart motion to said support, and,  
 a platen motor to impart motion to said pad.  
 
     
     
         26 . The apparatus of  claim 23 , further comprising a source positioned to dispense liquid from said liquid source between said polishing face and said support surface.  
     
     
         27 . The apparatus of  claim 23 , wherein said source is positioned to dispense liquid through said pad.  
     
     
         28 . A method of limiting mechanical abrasion of a surface during polishing, said method comprising: 
 providing a polishing pad including a first member comprising a first material that is abrasive to a wafer surface and structurally degradable during polishing;    incorporating a second member in the polishing pad comprising a second material that is less degradable and less abrasive than the first material to limit the amount of the first member available to abrade the surface; and,    polishing the wafer surface with the first member.    
     
     
         29 . The method of  claim 28 , further comprising removing a portion of the second member to expose an amount of the first member effective to polish the surface.  
     
     
         30 . The method of  claim 29 , wherein: 
 said incorporating further comprises incorporating a second member comprising a material that is more soluble in a solvent than the first material; and,    said removing further comprises removing a portion of the second member using the solvent.    
     
     
         31 . A method of performing mechanical polishing of a surface, comprising: 
 providing a polishing pad having a first member comprising a first material that is abrasive to a surface and structurally degradable during polishing that extends beyond a second member comprising a second material that is less degradable and less abrasive than the first material; and,    polishing the surface with the first member.    
     
     
         32 . The method of  claim 31 , wherein said polishing further comprises polishing the surface with the first member until the second member contacts the surface.  
     
     
         33 . The method of  claim 31 , further comprising providing liquid on the surface during said polishing.  
     
     
         34 . The method of  claim 31 , wherein said step of providing comprises: 
 providing a polishing pad having a first member comprising an abrasive first material that is structurally degradable during polishing, and a second member comprising a second material that is less degradable and less abrasive than the first material; and,    removing a portion of the second member to expose an amount of the first member effective to polish the surface.    
     
     
         35 . The method of  claim 34 , wherein said removing includes chemically stripping the second member.  
     
     
         36 . The method of  claim 31 , wherein said providing further comprises providing an erodible, abrasive first material having a matrix material containing discrete particles of abrasive material distributed throughout and a less erodible.  
     
     
         37 . The method of  claim 36 , wherein said providing a second material further comprises providing a substantially nonerodible second material.  
     
     
         38 . The method of  claim 37 , wherein said providing a second material further comprises providing a substantially nonabrasive second material.  
     
     
         39 . The method of  claim 31 , wherein said providing a second material further comprises providing a substantially nonabrasive second material.  
     
     
         40 . A method of performing chemical mechanical polishing of a wafer surface, comprising: 
 providing a polishing pad having a first member comprising a first material that is abrasive to a wafer surface and erodible in polishing chemicals extending a predetermined distance beyond a second member comprising a second material that is substantially nonerodible in polishing chemicals and substantially nonabrasive to a wafer surface;    dispensing the polishing chemicals onto the wafer surface; and,    polishing the wafer surface with the first member for a period of time sufficient to erode the first member to be substantially flush with the second member.    
     
     
         41 . The method of  claim 40 , wherein said providing includes providing a first member comprising polyurethane containing discrete abrasive particles ranging from 15 nm-1000 nm in size and selected from the group consisting of SiO 2 , CeO 2 , Al 2 O 3 , Ta 2 O 5 , and MnO 2  and a second member comprising a soluble polyacrylate.  
     
     
         42 . The method of  claim 41 , further comprising removing a portion of the second member by exposing the polyacrylate material to a HCl/H 2 O solution to expose an amount of the first member effective to polish the surface.  
     
     
         43 . A method of forming a polishing pad having a polishing face, comprising: 
 providing a polishing pad having a first member comprising an abrasive first material that is structurally degradable during polishing; and,    incorporating a second member in the polishing pad comprising a second material that is sufficiently less degradable and less abrasive than the first material to limit the amount of the first member available to abrade the surface.    
     
     
         44 . The method of  claim 43 , further comprises removing a portion of the second member to expose an amount of the first member effective to polish the surface.  
     
     
         45 . The method of  claim 44 , wherein: 
 said incorporating further comprises incorporating a second member comprising a material that is more soluble in a solvent than the first material; and,    said removing further comprises removing a portion of the second member using the solvent.