Retainer for chemical mechanical polishing carrier head

Abstract

A retaining ring for a carrier head of a chemical mechanical polishing system includes an annular outer portion having an annular outer surface and a plurality of flanges projecting radially inward from the annular outer portion. Adjacent flanges are separated by a gap and inner ends of the plurality of flanges provide an inner surface to contact a substrate held in the carrier head. The plurality of flanges are canted relative to radial direction.

What is claimed is: 
     
         1 . A retaining ring for a carrier head of a chemical mechanical polishing system, the retaining ring comprising:
 an annular outer portion, the annular outer portion having a cylindrical outer surface;   a plurality of flanges projecting radially inward from the annular outer portion with adjacent flanges separated by a gap and with inner ends of the plurality of flanges providing an inner surface to contact a substrate held in the carrier head, wherein each flange of the plurality of flanges is canted relative to a respective radial direction from the flange.   
     
     
         2 . The retaining ring of  claim 1 , wherein the flanges are formed of a material sufficiently flexible that in operation one or more flanges contacted by the substrate will flex radially outward. 
     
     
         3 . The retaining ring of  claim 1 , wherein for each flange of the plurality of flanges, a midline of the flange forms an oblique angle of 30°-60° with a radial segment that passes through the center of the retaining ring and through the midline. 
     
     
         4 . The retaining ring of  claim 3 , wherein the oblique angle is between 40°-50°. 
     
     
         5 . The retaining ring of  claim 4 , wherein the oblique angle is 45°. 
     
     
         6 . The retaining ring of  claim 1 , wherein the flanges are spaced uniformly along the inner surface. 
     
     
         7 . The retaining ring of  claim 6 , wherein the plurality of flanges consist of twenty to eighty flanges. 
     
     
         8 . The retaining ring of  claim 1 , wherein the inner ends of the plurality of flanges define a circle having a diameter of 302 to 305 mm. 
     
     
         9 . The retaining ring of  claim 1 , wherein an inner end surface of each flange of the plurality of flanges is angled normal to the respective radial direction of the flange. 
     
     
         10 . The retaining ring of  claim 1 , wherein a plurality of channels are formed in a lower surface of the annular outer portion, each channel of the plurality of channels extending from a gap to the outer surface of the annular outer portion. 
     
     
         11 . The retaining ring of  claim 10 , wherein there are fewer channels than gaps. 
     
     
         12 . The retaining ring of  claim 11 , comprising one channel for every ten gaps. 
     
     
         13 . The retaining ring of  claim 10 , wherein the plurality of channels have a height less than a height of the plurality of flanges. 
     
     
         14 . The retaining ring of  claim 13 , wherein each channel has a width equal to a width of the gap. 
     
     
         15 . The retaining ring of  claim 9 , wherein each channel is canted relative to a respective radial direction from the channel. 
     
     
         16 . The retaining ring of  claim 14 , wherein each channel is canted at the same angle as the gap from which the channel extends.