Retaining-ring-less cmp process

Abstract

Exemplary carrier heads for a chemical mechanical polishing apparatus may include a carrier body. The carrier heads may include a flexible membrane coupled with the carrier body. The flexible membrane may include a substrate-receiving surface that faces away from the carrier body. The substrate-receiving surface may include a plurality of gripping elements that protrude away from the substrate-receiving surface. Each of the plurality of gripping elements may have a maximum lateral dimension that is no greater than 2 mm.

What is claimed is: 
     
         1 . A carrier head for a chemical mechanical polishing apparatus, comprising:
 a carrier body;   a flexible membrane coupled with the carrier body, the flexible membrane comprising a substrate-receiving surface that faces away from the carrier body, wherein:
 the substrate-receiving surface comprises a plurality of gripping elements that protrude away from the substrate-receiving surface; and 
 each of the plurality of gripping elements has a maximum lateral dimension that is no greater than 2 mm. 
   
     
     
         2 . The carrier head for a chemical mechanical polishing apparatus of  claim 1 , wherein:
 each of the plurality of gripping elements comprises a wide base that tapers to a gripping surface.   
     
     
         3 . The carrier head for a chemical mechanical polishing apparatus of  claim 2 , wherein:
 the gripping surface is convex.   
     
     
         4 . The carrier head for a chemical mechanical polishing apparatus of  claim 2 , wherein:
 the gripping surface is concave.   
     
     
         5 . The carrier head for a chemical mechanical polishing apparatus of  claim 1 , wherein:
 each of the plurality of gripping elements is substantially mushroom-shaped.   
     
     
         6 . The carrier head for a chemical mechanical polishing apparatus of  claim 1 , further comprising:
 a plurality of substrate retaining members coupled with the carrier body, wherein each of the plurality of substate retaining members is disposed at a different angular position about a periphery of the substrate-receiving surface.   
     
     
         7 . The carrier head for a chemical mechanical polishing apparatus of  claim 6 , wherein:
 the plurality of retaining members collectively extend about less than 20% of the periphery of the substrate-receiving surface.   
     
     
         8 . The carrier head for a chemical mechanical polishing apparatus of  claim 1 , further comprising:
 an adhesive applied to a gripping surface of at least some of the plurality of gripping elements.   
     
     
         9 . The carrier head for a chemical mechanical polishing apparatus of  claim 1 , wherein:
 each of the plurality of gripping elements has a maximum lateral dimension that is no greater than 0.1 mm.   
     
     
         10 . The carrier head for a chemical mechanical polishing apparatus of  claim 1 , wherein:
 each of the plurality of gripping elements is flexible in a lateral direction.   
     
     
         11 . A flexible membrane for a chemical mechanical polishing apparatus, comprising:
 a flexible membrane body having a substrate-receiving surface, wherein:
 the substrate-receiving surface comprises a plurality of gripping elements that protrude away from the substrate-receiving surface; and 
 each of the plurality of gripping elements has a maximum lateral dimension that is no greater than 2 mm. 
   
     
     
         12 . The flexible membrane for a chemical mechanical polishing apparatus of  claim 11 , wherein:
 each of the plurality of gripping elements comprises a wide base that tapers to a gripping surface.   
     
     
         13 . The flexible membrane for a chemical mechanical polishing apparatus of  claim 12 , wherein:
 the gripping surface is convex.   
     
     
         14 . The flexible membrane for a chemical mechanical polishing apparatus of  claim 12 , wherein:
 the gripping surface is concave.   
     
     
         15 . The flexible membrane for a chemical mechanical polishing apparatus of  claim 11 , wherein:
 a height of each of the plurality of gripping elements is no greater than 1 mm.   
     
     
         16 . The flexible membrane for a chemical mechanical polishing apparatus of  claim 11 , wherein:
 an open area of the substrate-receiving surface is less than 50%.   
     
     
         17 . A method of polishing a substrate, comprising:
 engaging a substrate with a plurality of gripping elements of a substrate-receiving surface of a flexible membrane of a carrier head;   flowing a polishing slurry from a slurry source to a polishing pad; and   moving the carrier head to polish the substrate atop the polishing pad.   
     
     
         18 . The method of polishing a substrate of  claim 17 , wherein:
 moving the carrier head comprises one or both of rotating the carrier head and laterally translating the carrier head relative to the polishing pad.   
     
     
         19 . The method of polishing a substrate of  claim 17 , wherein:
 the carrier head comprises a plurality of substrate retaining members that are disposed at different angular positions about a periphery of the substrate-receiving surface.   
     
     
         20 . The method of polishing a substrate of  claim 17 , wherein:
 each of the plurality of substrate retaining members comprises an inner portion that contacts a periphery of the substrate and that terminates prior to reaching the polishing pad and an outer region that contacts the polishing pad.