Retaining ring for a chemical mechanical polishing tool

Abstract

A retaining ring for a chemical mechanical polishing tool comprises a pad side surface. The pad side surface has an edge portion adjacent its outer circumference. A surface normal of the edge portion and a surface normal of the pad side surface include an acute angle. Additionally, or alternatively, the retaining ring may comprise at least one groove extending from an inner circumference of the pad side surface to the outer circumference of the pad side surface. The groove comprises at least one edge portion adjacent the pad side surface. A surface normal of the at least one edge portion and a surface normal of the pad side surface include an acute angle.

1 . A retaining ring for a chemical mechanical polishing tool comprising a pad side surface, said pad side surface having an edge portion adjacent an outer circumference thereof, wherein a surface normal of said edge portion and a surface normal of said pad side surface include an acute angle. 
     
     
         2 . The retaining ring of  claim 1 , wherein said edge portion is chamfered. 
     
     
         3 . The retaining ring of  claim 2 , wherein said surface normal of said edge portion and said surface normal of said pad side surface include an angle in a range from about 35-55 degrees. 
     
     
         4 . The retaining ring of  claim 1 , wherein said edge portion has a rounded shape. 
     
     
         5 . The retaining ring of  claim 4 , wherein a cross-section of said edge portion along a radial plane comprises a substantially elliptical arc section. 
     
     
         6 . The retaining ring of  claim 5 , wherein said cross-section of said edge portion along said radial plane comprises a substantially circular arc section. 
     
     
         7 . The retaining ring of  claim 6 , wherein said substantially circular arc section has a radius in a range from about 0.5 mm to about 5 mm. 
     
     
         8 . The retaining ring of  claim 1 , wherein said pad side surface comprises at least one groove extending from an inner circumference of said pad side surface to an outer circumference of said pad side surface, said groove comprising at least one edge portion adjacent said pad side surface, wherein a surface normal of said at least one edge portion and a surface normal of said pad side surface include an acute angle. 
     
     
         9 . The retaining ring of  claim 8 , wherein said angle between said surface normal of said at least one edge portion of said groove and said pad side surface has a value in a range from about 35-55 degrees. 
     
     
         10 . A retaining ring for a chemical mechanical polishing tool comprising a pad side surface, wherein said pad side surface comprises at least one groove extending from an inner circumference of said pad side surface to an outer circumference of said pad side surface, said at least one groove comprising at least one edge portion adjacent said pad side surface, wherein a surface normal of said at least one edge portion and a surface normal of said pad side surface include an acute angle. 
     
     
         11 . The retaining ring of  claim 10 , wherein said at least one edge portion is chamfered. 
     
     
         12 . The retaining ring of  claim 10 , wherein said surface normal of said at least one edge portion and said surface normal of said pad side surface include an angle in a range from about 35-55 degrees. 
     
     
         13 . The retaining ring of  claim 12 , wherein said at least one edge portion is rounded. 
     
     
         14 . The retaining ring of  claim 13 , wherein a cross-section of said groove along a plane substantially perpendicular to a length direction of said groove comprise a substantially elliptical arc section. 
     
     
         15 . The retaining ring of  claim 14 , wherein said arc section is substantially circular. 
     
     
         16 . The retaining ring of  claim 15 , wherein said arc section has a radius in a range from about 0.5 mm to about 5 mm. 
     
     
         17 . The retaining ring of  claim 10 , wherein said at least one groove is inclined relative to a radius of said retaining ring running through an end of said groove at an inner circumference of said retaining ring, and wherein each of said grooves comprises one edge portion wherein a surface normal of said edge portion and said surface normal of said pad side surface include an acute angle, said edge portion being provided on a first side of said groove nearer to said radius than a second side of said groove. 
     
     
         18 . The retaining ring of  claim 17 , wherein a surface normal of another edge portion of said groove and said surface normal of said pad side surface are substantially perpendicular to each other. 
     
     
         19 . A chemical mechanical polishing tool, comprising:
 a retaining ring according to  claim 17 ; and   a drive unit adapted to rotate said retaining ring in a direction of rotation, wherein said direction of rotation is adapted such that said at least one groove is inclined forwardly in said direction of rotation.   
     
     
         20 . A method of chemical mechanical polishing, comprising:
 providing a retaining ring comprising a pad side surface, said pad side surface comprising at least one groove extending from an inner circumference of said pad side surface to an outer circumference of said pad side surface, said at least one groove comprising an edge portion, wherein a surface normal of said edge portion and a surface normal of said pad side surface include an acute angle; and   rotating said retaining ring relative to a polishing pad in a direction of rotation, wherein said direction of rotation is adapted such that said at least one groove moves ahead of said edge.