Polishing pad assembly, apparatus for polishing a wafer including the polishing pad assembly and method for polishing a wafer using the polishing pad assembly

Abstract

An apparatus for polishing a wafer is provided. The apparatus comprises a polishing pad for polishing the wafer. The polishing pad is divided into multiple portions that are rotated in a substantially same direction. At least one of the portions of the polishing pad is adapted to rotate at a speed different than the other portions. A driving unit is also provided for moving the polishing pad. A polishing head is employed for maintaining the side of the wafer to be polished engaged with the polishing pad, for contacting the polished surface of the wafer with the polishing pad, and for rotating the wafer.

1 . A polishing pad assembly comprising: 
 a polishing pad for polishing a wafer, the polishing pad divided into multiple portions that are adapted to rotate in a substantially same direction, at least one of the portions of the polishing pad adapted to rotate at a speed different than the other portions; and    a driving unit for moving the polishing pad.    
     
     
         2 . The polishing pad assembly of  claim 1 , wherein the polishing pad is adapted to reciprocally move to polish the wafer, and the wafer is adapted to reciprocally move between the portions of the polishing pad.  
     
     
         3 . The polishing pad assembly of  claim 2 , wherein the polishing pad is adapted to reciprocally move so that the center of the wafer is located between an innermost interface of adjacent portions of the polishing pad and an outermost interface of adjacent portions of the polishing pad.  
     
     
         4 . The polishing pad assembly of  claim 1 , wherein the driving unit comprises at least three annular portions having diameters different from each other, and the portions of the polishing pad corresponding to the annular portions of the driving unit are attached to the annular portions of the driving unit, respectively.  
     
     
         5 . The polishing pad assembly of  claim 1 , wherein the driving unit comprises at least three rollers having substantially the same diameter, and the portions of the polishing pad comprise belts which are wound about the rollers.  
     
     
         6 . The polishing pad assembly of  claim 1 , wherein the polishing pad is divided into an odd number of portions.  
     
     
         7 . An apparatus for polishing a wafer comprising: 
 a polishing pad for polishing the wafer, the polishing pad being divided into multiple portions that are adapted to rotate in a substantially same direction, at least one of the portions of the polishing pad adapted to rotate at a speed different than the other portions;    a driving unit for moving the polishing pad; and    a polishing head for maintaining the side of the wafer to be polished engaged with the polishing pad, for contacting the polished surface of the wafer with the polishing pad, and for rotating the wafer.    
     
     
         8 . The apparatus of  claim 7 , wherein the polishing pad is reciprocally moved to polish the wafer, and the wafer is reciprocally moved between the portions of the polishing pad.  
     
     
         9 . The apparatus of  claim 8 , wherein the polishing pad is reciprocally moved so that the center of the wafer is located between an innermost interface of adjacent portions of the polishing pad and an outermost interface of adjacent portions of the polishing pad.  
     
     
         10 . The apparatus of  claim 8 , wherein the polishing head is reciprocally moved to move the polishing pad and the polishing head relative thereto.  
     
     
         11 . The apparatus of  claim 8 , wherein the polishing pad is reciprocally moved to move the polishing pad and the polishing head relative thereto.  
     
     
         12 . The apparatus of  claim 7 , wherein the driving unit comprises at least three annular portions having diameters different from each other, and the portions of the polishing pad corresponding to the annular portions of the driving unit are attached to the annular portions of the driving unit, respectively.  
     
     
         13 . The apparatus of  claim 7 , wherein the driving unit comprises at least three rollers having substantially the same diameter, and the portions of the polishing pad comprise belts which are wound about the rollers.  
     
     
         14 . The apparatus of  claim 7 , further comprising a slurry line for providing a polishing slurry to the polishing pad.  
     
     
         15 . The apparatus of  claim 14 , wherein the slurry line is positioned adjacent to the polishing head to provide the polishing slurry to a location on the polishing pad adjacent to the polishing head.  
     
     
         16 . The apparatus of  claim 14 , wherein the slurry line provides the polishing slurry to each of the portions of the polishing pad.  
     
     
         17 . The apparatus of  claim 7 , wherein the polishing pad is divided into an odd number of portions.  
     
     
         18 . A method of polishing a wafer comprising: 
 providing the wafer to be polished, a polishing head engaged with a polishing pad, the polishing pad being divided into multiple portions; and    moving the polishing pad to polish the wafer, at least one of the portions of the polishing pad having a speed different from that the remaining portions of the polishing pad, the portions of the polishing pad being moved in a substantially same direction.    
     
     
         19 . The method of  claim 18 , wherein a first portion of the wafer having a relatively lower polishing selectivity makes contact with the portion of the polishing pad having a relatively rate of speed, and a second portion of the wafer having a relatively higher polishing selectivity makes contact with the portion of the polishing pad having a relatively lower speed.  
     
     
         20 . The method of  claim 18 , further comprising rotating the wafer engaging the polishing pad.  
     
     
         21 . The method of  claim 18 , further comprising moving the polishing head and the polishing pad to reciprocally move the wafer between the portions of the polishing pad.  
     
     
         22 . The method of  claim 21 , wherein the polishing pad is reciprocally moved so that the center of the wafer is located between an innermost interface of adjacent portions of the polishing pad and between an outermost interface of adjacent portions of the polishing pad.  
     
     
         23 . The method of  claim 21 , wherein the polishing head is reciprocally moved to move the polishing pad and the polishing head relative thereto.  
     
     
         24 . The method of  claim 21 , wherein the polishing pad is reciprocally moved to move the polishing pad and the polishing head relative thereto.  
     
     
         25 . The method of  claim 18 , wherein the respective portions of the polishing pad have concentrically annular shapes having different diameters.  
     
     
         26 . The method of  claim 18 , wherein the respective portions of the polishing pad have a belt shape.  
     
     
         27 . The method of  claim 18 , further comprising providing slurry to the polishing pad.  
     
     
         28 . The method of  claim 27 , wherein the slurry is provided to a location on the polishing pad adjacent to the polishing head.  
     
     
         29 . The method of  claim 27 , wherein the slurry is provided to each of the respective portions of the polishing pad.  
     
     
         30 . The method of  claim 18 , wherein the polishing pad is divided into an odd number of portions.  
     
     
         31 . A method of polishing a wafer comprising: 
 providing the wafer to be polished, a polishing head engaged with a polishing pad, the polishing pad being divided into at least three portions; and    polishing the wafer to form a first region polished by a first portion of the polishing pad, a second region polished by a second portion of the polishing pad, and a third region polished by the first and second portions of the polishing pad.    
     
     
         32 . The method of  claim 31 , wherein polishing the wafer comprises: 
 rotating the polishing head; and    moving the polishing pad and the polishing head relatively to the wafer so as to reciprocally move the wafer between the first and second portions of the polishing pad.    
     
     
         33 . The method of  claim 32 , wherein the polishing pad is reciprocally moved so that the center of the wafer is located between an innermost interface of adjacent portions of the polishing pad and an outermost interface of adjacent portions of the polishing pad.  
     
     
         34 . The method of  claim 32 , wherein the polishing head and the polishing pad are moved relatively to the wafer so as to form the third region.  
     
     
         35 . The method of  claim 31 , wherein the first region corresponds to a central region of the wafer, the second region corresponds to an edge region of the wafer, and the third region corresponds to a region between the central region and the edge region.  
     
     
         36 . The method of  claim 31 , wherein the first portion of the polishing pad has a speed different from that of the second portion of the polishing pad.  
     
     
         37 . The method of  claim 31 , further comprising providing a polishing slurry to the polishing pad.  
     
     
         38 . The method of  claim 31 , wherein the polishing pad is divided into an odd number of portions.