Retaining ring design

Abstract

Embodiments herein relate to a retaining ring for use in a polishing process. The retaining ring includes an annular body having an upper surface and a lower surface. An inner surface is connected to the upper surface and the lower surface. The inner surface includes one or more surfaces that are used to retain a substrate during processing. The one or more surfaces have an angle relative to a central axis of the retaining ring. The inner surface also includes a plurality of facets. Channels are disposed within the retaining ring to allow passage of a polishing fluid from an inner surface to an outer surface of the retaining ring disposed opposite of the inner surface.

What is claimed is: 
     
         1 . A retaining ring, comprising:
 an annular body comprising:
 an upper surface; 
 a lower surface; 
 an outer surface extending between the upper surface and the lower surface; and an inner surface extending between the upper surface and the lower surface, wherein the inner surface comprises:
 a first tapered portion disposed at a first angle relative to a central axis; and 
 a second tapered portion disposed at a second angle relative to the central axis, and the second tapered portion is coincident with the lower surface at an adjoining edge, wherein a third angle formed between the second tapered portion and the lower surface is either acute or obtuse. 
 
   
     
     
         2 . The retaining ring of  claim 1 , wherein the first tapered portion has a diameter at a first end greater than a diameter at a second end, the second end adjoining a first end of the second tapered portion and the second tapered portion having a diameter at the second end less than the diameter at the second end of the first tapered portion. 
     
     
         3 . The retaining ring of  claim 1 , wherein the first tapered portion has a diameter at a first end greater than a diameter at a second end, the second end adjoining a first end of the second tapered portion and the second tapered portion having a diameter at the second end greater than the diameter at the second end of the first tapered portion. 
     
     
         4 . The retaining ring of  claim 2 , wherein the second angle is between 1 degree and 30 degrees towards the central axis. 
     
     
         5 . The retaining ring of  claim 3 , wherein the second angle is between 1 degree and 30 degrees away from the central axis. 
     
     
         6 . The retaining ring of  claim 1 , further comprising channels disposed within the annular body, wherein the channels have a first opening at the inner surface and a second opening at the outer surface. 
     
     
         7 . The retaining ring of  claim 1 , wherein the second tapered portion of the inner surface comprises an array of planar facets that are symmetrically positioned about the central axis. 
     
     
         8 . The retaining ring of  claim 1 , wherein the second tapered portion of the inner surface comprises an array of planar facets that are non-radially symmetrical about the central axis. 
     
     
         9 . The retaining ring of  claim 7 , wherein the first tapered portion of the inner surface has a frustoconical cross section. 
     
     
         10 . A retaining ring, comprising:
 an annular body comprising:
 an upper surface; 
 a lower surface; 
 an outer surface extending between the upper surface and the lower surface; 
 an inner surface extending between the upper surface and the lower surface, the inner surface comprising:
 a first tapered portion disposed at a first angle relative to a central axis; 
 a second tapered portion having an array of planar facets that are positioned about the central axis, the second tapered portion disposed at a second angle relative to the central axis and coincident with the lower surface at an adjoining edge, wherein the second tapered portion and lower surface define a third angle that is either acute or obtuse; and 
 a plurality of channels disposed within the annular body, wherein the annular channels have a first opening at the inner surface and a second opening at the outer surface. 
 
   
     
     
         11 . The retaining ring of  claim 10 , wherein the first tapered portion has a diameter at a first end greater than a diameter at a second end, the second end adjoining a first end of the second tapered portion and the second tapered portion having a diameter at the second end less than the diameter at the second end of the first tapered portion. 
     
     
         12 . The retaining ring of  claim 10 , wherein the first tapered portion has a diameter at a first end greater than a diameter at a second end, the second end adjoining a first end of the second tapered portion and the second tapered portion having a diameter at the second end greater than the diameter at the second end of the first tapered portion. 
     
     
         13 . The retaining ring of  claim 11 , wherein the second angle is between 1 degree and 30 degrees towards the central axis. 
     
     
         14 . The retaining ring of  claim 12 , wherein the second angle is between 1 degree and 30 degrees away from the central axis. 
     
     
         15 . The retaining ring of  claim 10 , wherein the array of planar facets are symmetrically positioned about the central axis. 
     
     
         16 . The retaining ring of  claim 10 , wherein the array of planar facets are non-radially symmetrical about the central axis. 
     
     
         17 . The retaining ring of  claim 10 , wherein the first tapered portion of the inner surface has a frustoconical cross section. 
     
     
         18 . A retaining ring, comprising:
 an annular body comprising:
 an upper surface; 
 a lower surface; 
 an outer surface extending between the upper surface and the lower surface; 
 an inner surface extending between the upper surface and the lower surface, the inner surface comprising:
 a first portion disposed substantially parallel relative to a central axis; 
 a second portion disposed at a first angle relative to the central axis, the second portion comprising an array of planar facets that are positioned about the central axis, the second portion coincident with the lower surface at an adjoining edge, wherein the second portion and lower surface define a second angle that is either acute or obtuse; 
 a plurality of channels disposed within the annular body, wherein the annular channels have a first opening at the inner surface and a second opening at the outer surface. 
 
   
     
     
         19 . The retaining ring of  claim 18 , wherein the array of planar facets are symmetrically positioned about the central axis. 
     
     
         20 . The retaining ring of  claim 18 , wherein the array of planar facets are non-radially symmetrical about the central axis.