Slurry distribution device for chemical mechanical polishing

Abstract

An apparatus for chemical mechanical polishing includes a rotatable platen having a surface to support a polishing pad, a carrier head to hold a substrate in contact with the polishing pad, and a polishing liquid distribution system. The polishing liquid distribution system includes a dispenser positioned to deliver a polishing liquid to a portion of a polishing surface of the polishing pad, and a first barrier positioned before the portion of the polishing surface and configured to block used polishing liquid from reaching the portion of the polishing surface. The first barrier includes a solid first body having a first flat bottom surface and having a first leading surface configured to contact the used polishing liquid.

What is claimed is: 
     
         1 . An apparatus for chemical mechanical polishing, comprising:
 a rotatable platen having a surface to support a polishing pad;   a carrier head to hold a substrate in contact with the polishing pad; and   a polishing liquid distribution system, the polishing liquid distribution system including
 a dispenser positioned to deliver a polishing liquid at a dispensing position onto a polishing surface of the polishing pad, and 
 a first barrier including a first solid body having a first leading surface and a first flat bottom surface, the first flat bottom surface positioned to contact the polishing surface, the first barrier located after the dispensing position to spread fresh polishing liquid delivered by the dispenser onto the polishing surface, and wherein the first leading surface of the first barrier curves about an axis perpendicular to the polishing surface. 
   
     
     
         2 . The apparatus of  claim 1 , comprising a first actuator configured to adjust a height of the first barrier relative to and/or a pressure of the first barrier on the polishing surface. 
     
     
         3 . The apparatus of  claim 1 , wherein the platen is configured to rotate to provide a direction of motion below the first barrier, and the first leading surface of the first barrier is curved such that such that a concave side of the first leading surface of the first barrier faces in the direction of motion. 
     
     
         4 . The apparatus of  claim 1 , comprising a second barrier including a second solid body having a second leading surface and a second flat bottom surface, the second barrier positioned before the dispenser to block used polishing liquid from reaching the dispensing position, and wherein a second leading surface of the second barrier curves about an axis perpendicular to the polishing surface. 
     
     
         5 . The apparatus of  claim 4 , wherein the platen is configured to rotate to provide a direction of motion below the first barrier and the second barrier, the first leading surface of the first barrier is curved such that such that a concave side of the leading surface of the first barrier faces in the direction of motion, and the second leading surface of the second barrier is curved such that such that a concave side of the second leading surface of the second barrier faces in the direction of motion. 
     
     
         6 . The apparatus of  claim 4 , wherein a radius of curvature of the second leading surface is less than a radius of curvature of the first leading surface. 
     
     
         7 . The apparatus of  claim 4 , comprising a first actuator configured to adjust a height of the first barrier relative to the polishing surface and/or a pressure of the first barrier on the polishing surface, and/or a second actuator configured to independently adjust a height of the second barrier relative to the polishing surface and/or a pressure of the second barrier on the polishing surface. 
     
     
         8 . The apparatus of  claim 1 , wherein the first body has a width along a direction of motion of the polishing pad below the first barrier greater than a height of the first body perpendicular to the polishing surface. 
     
     
         9 . The apparatus of  claim 1 , comprising a splash guard projecting from the first leading surface. 
     
     
         10 . The apparatus of  claim 1 , wherein the first leading surface is oriented at an acute angle relative to the polishing surface.