Polishing pad and method of polishing wafer

Abstract

A wafer polishing method is provided. A first polishing pad comprising a plurality of abrasive units is provided. A first polishing operation is performed on the first polishing pad to planarize a wafer. Thereafter, a second polishing pad comprising a plurality of abrasive units is provided. The surface of the abrasive unit in contact with the wafer is roughened. A second polishing operation is performed on the second polishing pad. Since a second polishing operation using a second polishing pad with a roughened surface is performed, gradual reduction of polishing rate as the polish layer is planarized can be avoided.

1 . A polishing pad, comprising: 
 a plurality of abrasive units each containing: 
 an adhesive compound; and  
 a plurality of abrasive particles distributed evenly within the adhesive compound,  
 wherein the surface of the abrasive units in contact with the surface of a wafer is roughened and the abrasive units are shaped into a triangular cone, hexagonal cone or circular cylinder and set up as an array.  
   
     
     
         2 . The polishing pad of  claim 1 , wherein material constituting the abrasive particles comprises cerium oxide (CeO 2 ).  
     
     
         3 . The polishing pad of  claim 1 , wherein material constituting the adhesive compound comprises a resin.  
     
     
         4 . A method of polishing a wafer, comprising the steps of: 
 providing a first polishing pad, wherein the first polishing pad comprises a plurality of first abrasive units each fabricated using an adhesive compound with evenly distributed abrasive particles therein;    performing a first polishing operation on the first polishing pad to planarize a wafer;    providing a second polishing pad, wherein the second polishing pad comprises a plurality of second abrasive units each fabricated using an adhesive compound with evenly distributed abrasive particles therein, and the surface of the second abrasive units in contact with the wafer is roughened and the abrasive units are shaped into a triangular cone, hexagonal cone or circular cylinder and set up as an array; and    performing a second polishing operation on the second polishing pad.    
     
     
         5 . The wafer polishing method of  claim 4 , wherein material constituting the abrasive particles comprises cerium oxide (CeO 2 ).  
     
     
         6 . The wafer polishing method of  claim 4 , wherein material constituting the adhesive compound comprises a resin.  
     
     
         7 - 10 . (cancelled)  
     
     
         11 . The wafer polishing method of  claim 4 , wherein the second polishing operation is conducted at a rate faster than that of the first polishing operation.  
     
     
         12 . The wafer polishing method of  claim 4 , wherein the second polishing operation is conducted at least at a same rate as the first polishing operation.