CMP polishing heads retaining ring groove design for microscratch reduction

Abstract

A chemical-mechanical polish (CMP) machine and fabrication process using the same. The CMP machine has a CMP retaining ring comprising: an inner peripheral surface; an outer peripheral surface; a lower surface adapted to contact and depress an upper surface of a polishing pad during chemical mechanical polishing of a lower surface of a substrate. The substrate is contained within the inner peripheral surface of the retaining ring during chemical mechanical polishing. At least a groove on the lower surface of the retaining ring. At least a portion of the groove has a rounded contour. In an aspect, the groove has a semicircle profile. In another aspect, the groove has a semicircle profile and a curved top corner profile at adjacent to the lower surface of the retaining ring. The retaining ring with a curved portion of groove reduces the accumulation of dried slurry in the groove and thus reduces micro-scratches.

1 . A CMP retaining ring, comprising: 
 an inner peripheral surface;    an outer peripheral surface;    a lower surface adapted to contact and depress an upper surface of a polishing pad during chemical mechanical polishing of a lower surface of a substrate;    at least a groove on said lower surface of said retaining ring; and said groove extending from a position at or adjacent said inner peripheral surface of said retaining ring, to a position at or adjacent said outer peripheral surface of said retaining ring;    at least a portion of said groove has a rounded contour or slanted contour.    
     
     
         2 . The CMP retaining ring of  claim 1  wherein said groove has a semicircle profile.  
     
     
         3 . The CMP retaining ring of  claim 1  wherein said groove has a semicircle profile and said groove has a rounded top corner adjacent to the lower surface of the retaining ring.  
     
     
         4 . The CMP retaining ring of  claim 1  wherein said groove has a semicircle profile with a radius between 2 and 15 mm.  
     
     
         5 . The CMP retaining ring of  claim 1  wherein said groove has at least one rounded corner.  
     
     
         6 . The CMP retaining ring of  claim 1  wherein said groove has rounded corners adjacent to the bottom of said grooves.  
     
     
         7 . The CMP retaining ring of  claim 1  wherein said groove has rounded top corners adjacent to the lower surface of said retaining ring.  
     
     
         8 . The CMP retaining ring of  claim 1  wherein the cross-sectional area of said groove changes along the length of said groove.  
     
     
         9 . The CMP retaining ring of  claim 1  wherein said groove has a width between 1 mm and 30 mm; said groove has a depth between 1 and 15 mm.  
     
     
         10 . The CMP retaining ring of  claim 1  wherein said groove has vertical sidewalls or sloped sidewalls.  
     
     
         11 . The CMP retaining ring of  claim 1  wherein said groove has vertical sidewalls and an about horizontal bottom and at least one rounded corner between said vertical sidewalls and said horizontal bottom.  
     
     
         12 . The CMP retaining ring of  claim 1  wherein said groove has straight sidewalls and top and bottom corners; at least one of said corners is rounded or curvilinear.  
     
     
         13 . The CMP retaining ring of  claim 1  wherein said retaining ring can further comprise other channels; the lower surface of the retaining ring can further comprise a plurality of protrusions and recesses or a mixture of both.  
     
     
         14 . A process for chemical-mechanical polishing a substrate comprising: 
 said substrate is disposed within a polishing head facing a polishing table; said substrate is retained within the polishing head by a retainer ring, and at least a portion of said groove has a rounded contour;    supplying a slurry to said polishing table or to said polish head;    moving the polishing table and/or the polishing head to chemically polish the wafer.    
     
     
         15 . The process of  claim 14  which further includes: said substrate is a wafer; forming a deposition layer on the surface of said wafer and chemical mechanically polishing said deposition layer.  
     
     
         16 . The process of  claim 14  wherein said groove has a semicircle profile.  
     
     
         17 . The process of  claim 14  wherein said groove has a semicircle profile and said groove has a rounded corner adjacent to the lower surface of the retaining ring.  
     
     
         18 . The process of  claim 14  wherein said groove has at least one rounded corner.  
     
     
         19 . The process of  claim 14  wherein said grooves has at least one rounded bottom corner.  
     
     
         20 . The process of  claim 14  wherein said groove has rounded edges adjacent to the bottom of said grooves.  
     
     
         21 . The process of  claim 14  wherein said groove has rounded top edges adjacent to the lower surface of said retaining ring.  
     
     
         22 . The process of  claim 14  wherein said groove has a width between 1 and 30 mm; said groove has a depth between 1 and 15 mm.