Retainer ring for chemical mechanical polishing apparatus and chemical mechanical polishing apparatus including the same

Abstract

The present disclosure relates to a retainer ring for a chemical mechanical polishing apparatus and a chemical mechanical polishing apparatus including the same, and the retainer ring of a head portion in a chemical mechanical polishing apparatus includes: an inner ring configured to surround a circumference edge of a wafer; an outer ring surrounding the inner ring; and a fluid flow path formed between the inner ring and the outer ring, the fluid flow path defined by an outward-facing surface of the inner ring and an inward-facing surface of the outer ring. The inward-facing surface of the outer ring includes at least one lower curved portion.

What is claimed is: 
     
         1 . A retainer ring of a head portion in a chemical mechanical polishing apparatus, comprising:
 an inner ring configured to surround a circumference edge of a wafer;   an outer ring surrounding the inner ring; and   a fluid flow path formed between the inner ring and the outer ring, the fluid flow path defined by an outward-facing surface of the inner ring and an inward-facing surface of the outer ring,   wherein the inward-facing surface of the outer ring includes at least one lower curved portion.   
     
     
         2 . The retainer ring of  claim 1 , wherein the outward-facing surface of the inner ring includes at least one upper curved portion. 
     
     
         3 . The retainer ring of  claim 1 , wherein the lower curved portion has a convex shape of a predetermined radius. 
     
     
         4 . The retainer ring of  claim 1 , wherein the lower curved portion has a concave shape of a predetermined radius. 
     
     
         5 . The retainer ring of  claim 2 , wherein the lower curved portion and the upper curved portion have an asymmetric shape. 
     
     
         6 . The retainer ring of  claim 2 , wherein a minimum interval between the lower curved portion and the upper curved portion divided by a thickness of the outer ring is 0.11 to 0.5. 
     
     
         7 . The retainer ring of  claim 1 , wherein the inward-facing surface of the outer ring of the fluid flow path includes at least one lower straight-line portion in a cross-sectional view. 
     
     
         8 . The retainer ring of  claim 7 , wherein an angle (θ 1 ) formed between the lower straight-line portion and a bottom surface of the outer ring and an angle (θ 2 ) formed between a bottom end portion of the lower curved portion and the bottom surface of the outer ring satisfy Relationship 1 below:
 <Relationship 1> 
 
       
         
           
             
               0 
               < 
               
                 θ 
                 2 
               
               < 
               
                 
                   90 
                   ⁢ 
                   ° 
                 
                 - 
                 
                   
                     θ 
                     1 
                   
                   . 
                 
               
             
           
         
       
     
     
         9 . The retainer ring of  claim 7 , wherein the lower straight-line portion and the lower curved portion are continuously disposed, and a thickness of the lower straight-line portion in a vertical direction is equal to or less than 0.3 times a thickness of the outer ring in the vertical direction. 
     
     
         10 . The retainer ring of  claim 7 , wherein the lower straight-line portion and the lower curved portion are continuously disposed, and a thickness of the lower straight-line portion in a vertical direction is equal to or greater than 0.7 times a thickness of the outer ring in the vertical direction. 
     
     
         11 . The retainer ring of  claim 1 , wherein in the outward-facing surface of the inner ring, a curved portion having a concave shape of a predetermined radius and a curved portion having a convex shape of a predetermined radius are continuously disposed. 
     
     
         12 . The retainer ring of  claim 11 , wherein a length ratio in a horizontal direction of the curved portion having the concave shape to the curved portion having the convex shape is 1:9 to 5:5. 
     
     
         13 . The retainer ring of  claim 11 , wherein a plurality of curved portions each having the concave shape of the predetermined radius and a plurality of curved portions each having the convex shape of the predetermined radius are continuously disposed. 
     
     
         14 . The retainer ring of  claim 11 , wherein the outward-facing surface of the inner ring defining the fluid flow path further comprises at least one upper straight-line portion. 
     
     
         15 . A retainer ring of a head portion in a chemical mechanical polishing apparatus, comprising:
 an inner ring configured to surround a circumference edge of a wafer;   an outer ring surrounding the inner ring; and   a fluid flow path formed between the inner ring and the outer ring, the fluid flow path defined by a surface of the inner ring and a surface of the outer ring,   wherein the surface of the outer ring defining the fluid flow path includes at least one lower curved portion and at least one lower straight-line portion.   
     
     
         16 . The retainer ring of  claim 15 , wherein the surface of the inner ring defining the fluid flow path includes at least one upper curved portion. 
     
     
         17 . The retainer ring of  claim 15 , wherein in the surface of the outer ring defining the fluid flow path, a plurality of lower curved portions each having a concave shape of a predetermined radius and a plurality of lower curved portions each having a convex shape of a predetermined radius are continuously disposed. 
     
     
         18 . The retainer ring of  claim 15 , wherein the lower straight-line portion and the lower curved portion are continuously disposed, and a thickness of the straight line portion in a vertical direction is equal to or less than 0.3 times a thickness of the outer ring in the vertical direction. 
     
     
         19 . The retainer ring of  claim 15 , wherein the lower straight-line portion and the lower curved portion are continuously disposed, and a thickness of the lower straight-line portion in a vertical direction is equal to or greater than 0.7 times a thickness of the outer ring. 
     
     
         20 . A chemical mechanical polishing apparatus, comprising:
 a polishing platen that is rotatable;   a polishing pad that is disposed on the polishing platen;   a head portion that is disposed above the polishing pad and configured to install a wafer;   a slurry supplying portion configured to supply a slurry to the polishing pad; and   a retainer ring in the head portion, the retainer ring configured to surround the wafer, the retainer ring including an inner ring configured to hold a circumference edge of the wafer, an outer ring surrounding the inner ring, and a fluid flow path disposed between the inner ring and the outer ring, the fluid flow path defined by an outward-facing surface of the inner ring and an inward-facing surface of the outer ring,   wherein the inward-facing surface of the outer ring includes at least one lower curved portion.