Apparatus for chemical mechanical polishing

Abstract

The present invention provides a chemical mechanical polishing apparatus for polishing a wafer. The chemical mechanical polishing apparatus comprises a platen, a polishing pad, a transparent element (transparent window), a slurry providing system, and a rotating carrier. The platen comprises a light source for projecting a light and a light detector for detecting the light reflected by the wafer. The polishing pad has a first opening on the platen. The transparent element is detachably located on the first opening to admit light. The slurry providing system provides slurry to the surface of the polishing pad. The rotating carrier holds the wafer and contacts the surface of the wafer with the slurry and the polishing pad to carry out the chemical mechanical polishing process.

What is claimed is:  
     
         1 . A chemical mechanical polishing apparatus for polishing a wafer, comprising: 
 a platen, comprising a light source for projecting a light and a light detector for detecting the light reflected by the wafer;    a polishing pad having a first opening on the platen;    a transparent element detachably located on the first opening for admitting light;    a slurry providing system, which provides a slurry to the surface of the polishing pad; and    a rotating carrier for holding the wafer and contacting the surface of the wafer with the slurry and the polishing pad to carry out the chemical mechanical polishing process.    
     
     
         2 . The chemical mechanical polishing apparatus as claimed in  claim 1 , wherein the light is a laser beam.  
     
     
         3 . The chemical mechanical polishing apparatus as claimed in  claim 1 , wherein the polishing pad comprises: 
 a first substrate having a second opening on the platen; and    a second substrate installed on the first substrate and having a third opening, wherein the second opening and the third opening constitute the first opening.    
     
     
         4 . The chemical mechanical polishing apparatus as claimed in  claim 3 , wherein the material type of the first substrate is suba IV.  
     
     
         5 . The chemical mechanical polishing apparatus as claimed in  claim 1 , wherein the material type of the second substrate is IC-1000.  
     
     
         6 . The chemical mechanical polishing apparatus as claimed in  claim 1 , wherein the transparent element is installed on the second opening.