Apparatus and method for slurry distribution

Abstract

A assembly for a chemical mechanical polishing apparatus includes a carrier head and a polishing liquid delivery ring. The carrier head has a substrate receiving surface and a retaining ring surrounding the substrate receiving surface. The polishing liquid delivery ring is coupled to the carrier head and surrounds the retaining ring. The polishing liquid delivery ring includes a reservoir to hold a liquid and an outlet in fluid communication with the reservoir and positioned to dispense the liquid to a location on a polishing surface outside the retaining ring.

1 . An assembly for a chemical mechanical polishing apparatus, comprising:
 a carrier head with a substrate receiving surface and a retaining ring surrounding the substrate receiving surface; and   a polishing liquid delivery ring coupled to the carrier head and surrounding the retaining ring, the polishing liquid delivery ring including a reservoir to hold a liquid and an outlet in fluid communication with the reservoir and positioned to dispense the liquid to a location on a polishing surface outside the retaining ring.   
   
   
       2 . The assembly of  claim 1 , wherein the reservoir comprises a recess formed in an upper surface of the polishing liquid delivery ring. 
   
   
       3 . The assembly of  claim 2 , wherein the recess is an annular recess surrounding the carrier head. 
   
   
       4 . The assembly of  claim 2 , wherein a passage is formed through the polishing liquid delivery ring from the reservoir to the outlet. 
   
   
       5 . The assembly of  claim 4 , wherein the passage is essentially vertical. 
   
   
       6 . The assembly of  claim 4 , wherein the passage is tilted. 
   
   
       7 . The assembly of  claim 6 , wherein the passage is angled outwardly from top to bottom. 
   
   
       8 . The assembly of  claim 1 , wherein the outlet is located on a bottom surface of the retaining ring. 
   
   
       9 . The assembly of  claim 1 , wherein the polishing liquid delivery ring includes a plurality of outlets in fluid communication with the reservoir, each outlet positioned to dispense the liquid to an associated location on the polishing surface outside the retaining ring. 
   
   
       10 . The assembly of  claim 1 , wherein the retaining ring has a bottom surface with slurry delivery channels. 
   
   
       11 . The assembly of  claim 1 , wherein the polishing liquid delivery ring includes an inwardly extending flange positioned on a top surface of the carrier head. 
   
   
       12 . The assembly of  claim 1 , wherein the flange is positioned on a top surface of the retaining ring. 
   
   
       13 . The assembly of  claim 12 , wherein the flange is positioned between the top surface of the retaining ring and a bottom surface of a housing of the carrier head. 
   
   
       14 . The assembly of  claim 1 , wherein the polishing liquid delivery ring is coupled to the carrier head by a bearing. 
   
   
       15 . The assembly of  claim 1 , further comprising a supply tube having an outlet positioned at least intermittently over the polishing liquid delivery ring. 
   
   
       16 . The assembly of  claim 15 , further comprising a carrier head support to hold the carrier head and a pump supported on the carrier head support to pump polishing liquid through the supply tube. 
   
   
       17 . The assembly of  claim 16 , further comprising a polishing liquid supply fluidly coupled to the pump and secured to the carrier head support. 
   
   
       18 . The assembly of  claim 16 , wherein the pump is configured to dispense the polishing slurry into the reservoir intermittently during polishing. 
   
   
       19 . The assembly of  claim 16 , wherein the pump is configured to dispense the polishing slurry into the reservoir continuously during polishing. 
   
   
       20 . A method for delivering a polishing liquid, comprising:
 delivering a polishing liquid into a reservoir of a polishing liquid delivery ring coupled to a carrier head; and   dispensing the polishing liquid from the reservoir through an outlet in fluid communication with the reservoir to a location on a polishing surface outside a retaining ring of the carrier head.