Method and polishing pad design enabling improved wafer removal from a polishing pad in a CMP process

Abstract

The invention provides a chemical mechanical polishing pad and method that enables improved wafer removal from the polishing pad after completion of chemical mechanical polishing of the wafer.

What is claimed is:  
     
         1 . A chemical mechanical polishing pad, comprising: 
 a top surface having a structure that forms a vacuum between the pad and a wafer during chemical mechanical polishing; and    at least one venting inlet capable of releasing the vacuum when the wafer is located over the venting inlet.    
     
     
         2 . The pad of  claim 1 , wherein the structure includes a plurality of perforations.  
     
     
         3 . The pad of  claim 1 , wherein the structure includes a plurality of grooves.  
     
     
         4 . The pad of  claim 1 , wherein the at least one venting inlet is connected to atmospheric pressure.  
     
     
         5 . The pad of  claim 1 , wherein the at least one venting inlet extends from the periphery of the top surface towards the center of the top surface.  
     
     
         6 . The pad of  claim 1 , wherein the at least one venting inlet is angled relative to a diameter of the pad.  
     
     
         7 . The pad of  claim 1 , wherein the at least one venting inlet passes through the full depth of the polishing pad.  
     
     
         8 . The pad of  claim 1 , wherein the at least one venting inlet passes through a portion of the depth of the polishing pad.  
     
     
         9 . The pad of  claim 1 , wherein the at least one venting inlet has a sloped surface.  
     
     
         10 . The pad of  claim 1 , wherein the at least one venting inlet tunnels through the pad to connect with the top surface of the pad.  
     
     
         11 . The pad of  claim 1 , wherein the at least one venting inlet tunnels underneath the pad to connect with the top surface of the pad and wherein a platen forms a bottom surface of the at least one venting inlet.  
     
     
         12 . A method for removing a wafer from a polishing head after chemical mechanical polishing, comprising: 
 applying a vacuum to a backside of the wafer;    moving the polishing head retaining the wafer so that the wafer is positioned over a venting inlet of a polishing pad;    releasing the vacuum from the backside of the wafer; and    removing the wafer from the polishing head.    
     
     
         13 . The method of  claim 12 , wherein the polishing pad has a top surface having a plurality of perforations.  
     
     
         14 . The method of  claim 12 , wherein the polishing pad has a top surface having a plurality of grooves.  
     
     
         15 . The method of  claim 12 , wherein the venting inlet is connected to atmospheric pressure.  
     
     
         16 . The method of  claim 12 , wherein the venting inlet extends from the periphery of a top surface of the pad towards a center of the top surface.  
     
     
         17 . The method of  claim 12 , wherein the venting inlet is angled relative to a diameter of the pad.  
     
     
         18 . The method of  claim 12 , wherein the venting inlet passes through the full depth of the polishing pad.  
     
     
         19 . The method of  claim 12 , wherein the venting inlet passes through a portion of the depth of the polishing pad.  
     
     
         20 . The method of  claim 12 , wherein the venting inlet has a sloped surface.  
     
     
         21 . The method of  claim 12 , wherein the venting inlet tunnels through the pad to connect with a top surface of the pad.  
     
     
         22 . The method of  claim 12 , wherein the venting inlet tunnels underneath the pad to connect with a top surface of the pad and wherein a platen forms a bottom surface of the venting inlet.  
     
     
         23 . The method of  claim 12 , wherein the method is performed in the order recited.  
     
     
         24 . The method of  claim 12 , wherein the moving is performed before the applying.  
     
     
         25 . A method for removing a wafer from a polishing head after chemical mechanical polishing, comprising: 
 applying a vacuum to a backside of the wafer;    moving the polishing head retaining the wafer to a periphery of a polishing pad;    rotating the polishing pad so that a venting inlet of the polishing pad is positioned under the wafer;    releasing the vacuum from the backside of the wafer; and    removing the wafer from the polishing head.    
     
     
         26 . The method of  claim 25 , wherein the polishing pad has a top surface having a plurality of perforations.  
     
     
         27 . The method of  claim 25 , wherein the polishing pad has a top surface having a plurality of grooves.  
     
     
         28 . The method of  claim 25 , wherein the venting inlet is connected to atmospheric pressure.  
     
     
         29 . The method of  claim 25 , wherein the venting inlet extends from the periphery of a top surface of the pad towards a center of the top surface.  
     
     
         30 . The method of  claim 25 , wherein the venting inlet is angled relative to a diameter of the pad.  
     
     
         31 . The method of  claim 25 , wherein the venting inlet passes through the full depth of the polishing pad.  
     
     
         32 . The method of  claim 25 , wherein the venting inlet passes through a portion of the depth of the polishing pad.  
     
     
         33 . The method of  claim 25 , wherein the venting inlet has a sloped surface.  
     
     
         34 . The method of  claim 25 , wherein the venting inlet tunnels through the pad to connect with a top surface of the pad.  
     
     
         35 . The method of  claim 25 , wherein the venting inlet tunnels underneath the pad to connect with a top surface of the pad and wherein a platen forms a bottom surface of the venting inlet.  
     
     
         36 . The method of  claim 25 , wherein the method is performed in the order recited.  
     
     
         37 . The method of  claim 25 , wherein the moving is performed before the applying.