Cmp retaining ring

Abstract

An improved chemical mechanical polishing retaining ring. A representative embodiment comprises a base portion made from a wear-resistant plastic material, and an upper portion, or backbone portion, made from a stiffer and more wear resistant material. One of the base or backbone portion is preferably overmolded onto the other. The base portion can be generally defined by a flat pad-contacting surface, an outer surface, and an inner surface. The base portion can additionally include channels extending from the outer surface to the inner surface to facilitate transfer of slurry to and from the substrate to be polished during the process. One or both of the base portion or backbone portion further includes a plurality of circular ribs that serve to create additional bonding surface with the overmolded material. The retaining ring may additionally includes a plurality of bosses with threaded insert holes by which the retaining ring is attached to a chemical mechanical polishing system.

1 . A retaining ring for use in a chemical mechanical polishing operation, comprising:
 an annular backbone portion having one or more circumferential and axially projecting backbone portion ribs with one or more channels defined by the one or more ribs, the ribs having an axial length greater than a corresponding width and the backbone portion comprising a rigid polymer material; and   a wear-resistant polymer base portion having a flat bottom surface, one or more circumferential and axially projecting base portion ribs with one or more channels defined by the one or more ribs, the ribs having an axial length greater than a corresponding width and a plurality of grooves in the bottom surface extending between an inner edge and an outer edge of the retaining ring, the grooves adapted to facilitate transfer of slurry during the polishing operation,   wherein the backbone portion and the base portion are bonded together by an overmolding process such that the backbone portion ribs mate to the base portion channels and the base portion ribs mate to the backbone portion channels such that they are directly interlacing and conforming with each other, and wherein the backbone portion ribs and the base portion ribs extend a portion of an axial thickness of the bonded backbone portion and base portion.   
     
     
         2 . The retaining ring of  claim 1 , wherein the plurality of grooves each include at least one divergent opening. 
     
     
         3 . The retaining ring of  claim 1 , wherein the base portion encapsulates the backbone portion. 
     
     
         4 . The retaining ring of  claim 1 , wherein the base portion comprises polyetheretherketone and the backbone portion comprises polyetheretherketone blended with ceramic. 
     
     
         5 . The retaining ring of  claim 1 , further comprising mounting fixtures for securing the retaining ring to a polishing unit. 
     
     
         6 . The retaining ring of  claim 1 , wherein the angle of the grooves relative to a line tangent to the outer edge is at least 135 degrees. 
     
     
         7 . The retaining ring of  claim 1 , wherein the grooves define a plurality of pad contacting areas, the pad contact areas comprising less than 92% of the area of the bottom surface. 
     
     
         8 . The retaining ring of  claim 1 , wherein the backbone portion ribs and base portion ribs are interlaced and the interlaced portion extends at least 25% of the axial thickness of the retaining ring. 
     
     
         9 . The retaining ring of  claim 1 , wherein the annular backbone portion has three axially projecting backbone portion ribs. 
     
     
         10 . The retaining ring of  claim 1 , wherein the polymer base portion has three axially projecting base portion ribs. 
     
     
         11 . The retaining ring of  claim 9 , wherein the polymer base portion has three axially projecting base portion ribs. 
     
     
         12 . The retaining ring of  claim 1 , wherein one of more of the base portion ribs has a flared cross-section.