Method and apparatus for chemical-mechanical polishing

Abstract

In accordance with at least one example embodiment, a method of chemical-mechanical polishing includes re-polishing a polished layer on a wafer based on a measured thickness of the polished layer. In accordance with at least one example embodiment, an apparatus for chemical-mechanical polishing may include a thickness measuring unit configured to measure a thickness of a polished surface on a wafer and to determine a re-polishing time based on the measured thickness. In accordance with example embodiments, a thickness deviation between different lots, wafers, or chips inside a wafer is reduced regardless of the durability of a polishing pad, a polishing head, or a disk used in a polishing apparatus.

1 . A method of chemical-mechanical polishing, the method comprising:
 first re-polishing of a polished layer on a wafer based on a measured thickness of the polished layer.   
   
   
       2 . The method of  claim 1 , further comprising:
 polishing a layer on the wafer to form the polished layer;   measuring a thickness of the polished layer;   first determining a re-polishing time based on the measured thickness; and wherein   the first re-polishing step re-polishes the polished layer for the determined re-polishing time.   
   
   
       3 . The method of  claim 2 , wherein the polishing step comprises:
 polishing the layer for a first fixed time on a first platen; and   polishing the layer for a second fixed time on a second platen.   
   
   
       4 . The method of  claim 2 , wherein the first re-polishing step re-polishes the polished layer on a third platen for the determined re-polishing time. 
   
   
       5 . The method of  claim 2 , further comprising:
 first cleaning the wafer after the polishing step and before the first re-polishing step.   
   
   
       6 . The method of  claim 5 , wherein the measuring step measures the thickness of the polished layer after the first cleaning step. 
   
   
       7 . The method of  claim 2 , further comprising:
 measuring the thickness of the re-polished layer;   second determining whether to re-polish the re-polished layer based on the measured thickness of the re-polished layer; and   second re-polishing the re-polished layer if the second determining step determines to re-polish the re-polished layer.   
   
   
       8 . The method of  claim 7 , further comprising:
 second cleaning the wafer after the second re-polishing step.   
   
   
       9 . The method of  claim 8 , wherein the measuring the thickness of the re-polished layer step measures the thickness of the re-polished layer after the second cleaning step. 
   
   
       10 . The method of  claim 7 , wherein the second re-polishing step re-polishes the re-polished layer on the third platen for the re-polishing time. 
   
   
       11 . The method of  claim 7 , further comprising:
 determining a second re-polishing time if the second determining step determines to re-polish the re-polished layer.   
   
   
       12 . The method of  claim 11 , wherein the second re-polishing time is based on a measured thickness of the re-polished layer. 
   
   
       13 . The method of  claim 11 , wherein the second re-polishing step re-polishes the re-polished layer on the third platen for the second re-polishing time. 
   
   
       14 . The method of  claim 2 , wherein the polishing step removes 50˜90% of a total amount of the layer removed by the method. 
   
   
       15 . The method of  claim 1 , wherein the layer is an insulation layer. 
   
   
       16 . The method of  claim 15 , wherein the layer is at least one of an inter-layer dielectric layer and a shallow trench isolation layer. 
   
   
       17 . The method of  claim 1 , wherein the layer is a metal layer. 
   
   
       18 . The method of  claim 17 , wherein the metal layer includes any one of tungsten (W), aluminum (Al), and copper (Cu) layers. 
   
   
       19 . The method of  claim 7 , wherein the second determining step determines whether the layer has been overpolished based on the measured thickness of the re-polished layer. 
   
   
       20 . The method of  claim 19 , further comprising:
 redepositing a layer on a surface of the wafer if the second determining step determines the layer has been overpolished.   
   
   
       21 - 25 . (canceled)