Fixed abrasive pad having different real contact areas and fabrication method thereof

Abstract

Disclosed is a method for fabricating a fixed abrasive pad in use of a chemical mechanical polishing process. The method includes: forming one or more etching molds providing a plurality of different real contact areas; attaching the etching mold(s) to a roller or press; and forming a fixed abrasive pad using the roller or press, The fixed abrasive pad has a plurality of polishing portions, each having a different real contact area. Especially, the fixed abrasive pad can comprise a low-density polishing portion having a real contact area less than 20% and a high-density polishing portion having a real contact area of 20%-50%.

1 . A method for fabricating a fixed abrasive pad, comprising the steps of: 
 forming one or more etching molds having a first region providing a relatively low real contact area and a second region providing a relatively high real contact area;    attaching the etching mold(s) to a roller; and    forming the fixed abrasive pad using the roller, wherein the fixed abrasive pad comprises a plurality of polishing portions in one pad, each polishing portion having a different real contact area from another.    
   
   
       2 . The method of  claim 1 , wherein the fixed abrasive pad comprises a low-density polishing portion having a real contact area of less than 20% and a high-density polishing portion having a real contact area of 20%-50%.  
   
   
       3 . The method of  claim 1 , wherein the roller comprises a plurality of through-holes, and the attaching the etching mold(s) comprises vacuum absorbing the etching mold(s) to the roller.  
   
   
       4 . The method of  claim 1 , comprising forming a plurality of etching molds, each etching mold providing a different real contact area.  
   
   
       5 . The method of  claim 1 , wherein the fixed abrasive pad is adapted for chemical mechanical polishing a wafer using chemical mechanical polishing equipment.  
   
   
       6 . A method for fabricating a fixed abrasive pad, comprising the steps of: 
 forming one or more etching molds, having a first region providing a relatively low real contact area and a second region providing a relatively high real contact area;    attaching the etching mold(s) to a press; and    forming a fixed abrasive pad using the press, wherein the fixed abrasive pad comprises a plurality of polishing portions in one pad, and each polishing portion has a different real contact area from another.    
   
   
       7 . The method of  claim 6 , wherein the fixed abrasive pad comprises a low-density polishing portion having a real contact area of less than 20% and a high-density polishing portion having a real contact area of 20%-50%.  
   
   
       8 . The method of  claim 6 , comprising forming a plurality of etching molds, each etching mold providing a different real contact area.  
   
   
       9 . The method of  claim 6 , wherein the fixed abrasive pad is adapted for chemical mechanical polishing a wafer using chemical mechanical polishing equipment.  
   
   
       10 . A fixed abrasive pad, comprising a first polishing portion having a relatively low real contact area and a second region having a relatively high real contact area.  
   
   
       11 . The fixed abrasive pad of  claim 10 , wherein the low-density polishing portion has a real contact area of less than 20% and the high-density polishing portion has a real contact area of 20%-50%.  
   
   
       12 . The fixed abrasive pad of  claim 10 , adapted for chemical mechanical polishing a wafer using chemical mechanical polishing equipment.  
   
   
       13 . A method for polishing a wafer, comprising the steps of: 
 polishing the wafer on a first polishing portion of a fixed abrasive pad comprising a plurality of polishing portions, the first polishing portion having a relatively low real contact area; and    polishing the wafer on a second polishing portion of the fixed abrasive pad, the second polishing portion having a relatively high real contact area.    
   
   
       14 . The method of  claim 13 , wherein the first polishing portion has a real contact area of less than 20% and the second polishing portion has a real contact area of 20%-50%.  
   
   
       15 . The method of  claim 13 , wherein the wafer has a predetermined pattern thereon.  
   
   
       16 . The method of  claim 13 , wherein polishing the wafer on the second polishing portion occurs after finishing polishing the wafer on the first polishing portion.  
   
   
       17 . A polishing apparatus, comprising: 
 a turn table;    a fixed abrasive pad on the turn table, comprising a first polishing portion having a relatively low real contact area and a second region having a relatively high real contact area; and    a wafer carrier adapted to hold a wafer and rotate the wafer against the fixed abrasive pad.    
   
   
       18 . The apparatus of  claim 15 , further comprising a chemical supplier over the turn table.  
   
   
       19 . The apparatus of  claim 15 , wherein the first polishing portion has a real contact area of less than 20% and the second polishing portion has a real contact area of 20% 50%.  
   
   
       20 . An apparatus for making a fixed abrasive pad, comprising: 
 one or more etching molds having a first region providing a relatively low real contact area and a second region providing a relatively high real contact area;    a roller or press to which the etching mold(s) are attached, adapted to press an abrasive particle mixture onto a pad base; and    one or more mechanisms for supplying the pad base and the abrasive particle mixture to the roller or press.