Wafer carrier and chemical mechanical polishing apparatus including the same

Abstract

Disclosed are a wafer carrier assembly and a chemical mechanical polishing apparatus including the same. The present wafer carrier for a chemical mechanical polishing apparatus comprises: a wafer carrier head rotatably mounted on the apparatus, having a lower surface for contacting a wafer; a retaining ring attached to the lower surface of the wafer carrier head, for retaining or preventing the wafer from moving from the wafer carrier head during rotational motion thereof; and a guard ring attached to the lower surface of the wafer carrier head a distance outside the retaining ring.

1 . A wafer carrier for a chemical mechanical polishing apparatus, comprising: 
 a wafer carrier head rotatably mounted on the apparatus, having a lower surface adapted for contact with a wafer;    a retaining ring extending from the lower surface of the wafer carrier head, for retaining the wafer on the wafer carrier head during rotational motion thereof; and    a guard ring extending from the lower surface of the wafer carrier head a distance outside of the retaining ring.    
     
     
         2 . The wafer carrier of  claim 1 , wherein an inner wall of the retaining ring is configured for contact with a periphery of the wafer.  
     
     
         3 . The wafer carrier of  claim 1 , wherein a protrusion height of the guard ring is substantially equal to or greater than that of retaining ring.  
     
     
         4 . The wafer carrier of  claim 2 , wherein a protrusion height of the guard ring is substantially equal to or greater than that of retaining ring.  
     
     
         5 . The wafer carrier of  claim 1 , wherein a protrusion height of the guard ring is greater than that of the retaining ring, relative to a surface of the wafer.  
     
     
         6 . The wafer carrier of  claim 2 , wherein a protrusion height of the guard ring is greater than that of the retaining ring, relative to a surface of the wafer.  
     
     
         7 . The wafer carrier of  claim 1 , wherein a bottom surface of the retaining ring is on substantially a same plane as a polished surface of the wafer.  
     
     
         8 . The wafer carrier of  claim 2 , wherein a bottom surface of the retaining ring is on substantially a same plane as a polished surface of the wafer.  
     
     
         9 . The wafer carrier of  claim 1 , further comprising a resilient member on the lower surface of the wafer carrier head.  
     
     
         10 . A chemical mechanical polishing apparatus, comprising: 
 a rotatable turntable;    a polishing pad on an upper surface of the turntable;    a wafer carrier support frame;    a wafer carrier rotatably mounted on the wafer carrier support frame, including (i) a wafer carrier head having a lower surface adapted for contacting a wafer, (ii) a retaining ring on the lower surface of the wafer carrier head, for retaining the wafer on the wafer carrier head, and (iii) a guard ring extending from the lower surface of the wafer carrier head a distance outside the retaining ring; and    a slurry providing unit for providing a slurry on an upper surface of the polishing pad.    
     
     
         11 . The apparatus of  claim 10 , wherein an inner wall of the retaining ring is configured for contact with a periphery of the wafer.  
     
     
         12 . The apparatus of  claim 10 , wherein a protrusion height of the guard ring is substantially equal to that of retaining ring.  
     
     
         13 . The apparatus of  claim 11 , wherein a protrusion height of the guard ring is substantially equal to that of retaining ring.  
     
     
         14 . The apparatus of  claim 10 , wherein a protrusion height of the guard ring is greater than that of the retaining ring, relative to a surface of the wafer.  
     
     
         15 . The apparatus of  claim 11 , wherein a protrusion height of the guard ring is greater than that of the retaining ring, relative to a surface of the wafer.  
     
     
         16 . The apparatus of  claim 10 , wherein a bottom surface of the retaining ring is on substantially a same plane as a polished surface of the wafer.  
     
     
         17 . The apparatus of  claim 10 , wherein a bottom surface of the retaining ring is on substantially a same plane as a polished surface of the wafer.  
     
     
         18 . The apparatus of  claim 11 , wherein the wafer carrier further includes a resilient member positioned on the lower surface of the wafer carrier head.  
     
     
         19 . A method of polishing a wafer, comprising the steps of: 
 providing a slurry on an upper surface of a polishing pad on an upper surface of a turntable; and    polishing a wafer on the polishing pad, wherein the wafer is retained by a retaining ring on a lower surface of a wafer carrier head, the wafer carrier head further including a guard ring extending from the lower surface of the wafer carrier head a distance outside the retaining ring.    
     
     
         20 . The method of  claim 19 , wherein the guard ring has a protrusion height greater than or equal to that of the retaining ring, relative to a surface of the wafer.