Wafer carrier for batch wafer polishing in wafer polishing machines

Abstract

A carrier assembly includes carrier protrusions extending outward from a base plate front face, one protrusion for each wafer to be polished. Each carrier protrusion has a front face separated from the base plate front face. An optional detachable ring may surround each protrusion front face to form a cavity for holding a wafer. In some examples of a carrier assembly, a frame having a separate aperture for each carrier protrusion holds all the detachable rings against the base plate front face. In other examples of a carrier assembly, the detachable rings are omitted, or a separate retaining ring for each carrier protrusion replaces the frame. A carrier protrusion may optionally be formed with edge relief to allow part of the wafer to deflect away from a polishing pad during polishing. A compressible elastic material may optionally be placed between a wafer and a carrier protrusion.

What is claimed is: 
     
         1 . A carrier assembly for wafer polishing, comprising:
 a base plate comprising a base plate front face;   at least three carrier protrusions extending outward from said base plate front face, wherein each of said carrier protrusions comprises:
 a protrusion front face separated from said base plate front face and from any other of said at least three carrier protrusions; and 
 a peripheral wall extending from said base plate to a perimeter of said protrusion front face; and 
   a frame comprising a front surface, wherein said frame is removably attachable to said base plate front face with a plurality of threaded fasteners, said frame is formed with a separate carrier protrusion aperture for each of said at least three carrier protrusions, and each of said carrier protrusion extends into a separate one of said carrier protrusion aperture with said front surface of said frame farther from said base plate front face than each of said protrusion front face.   
     
     
         2 . The carrier assembly of  claim 1 , further comprising at least three detachable rings, wherein each of said at least three detachable rings fits around a different one of said at least three carrier protrusions. 
     
     
         3 . The carrier assembly of  claim 2 , wherein each of said at least three detachable rings comprises a flange and said frame holds said flange against said base plate front face. 
     
     
         4 . The carrier assembly of  claim 2 , wherein each of said at least three detachable rings further comprises:
 an inner wall;   an outer wall; and   a plurality of transverse grooves from said inner wall to said outer wall.   
     
     
         5 . The carrier assembly of  claim 1 , wherein said base plate consists of five of said carrier protrusions. 
     
     
         6 . The carrier assembly of  claim 1 , wherein said protrusion front face on each of said at least three carrier protrusions has a peripheral shape corresponding to a peripheral shape of a wafer to be polished. 
     
     
         7 . The carrier assembly of  claim 1 , wherein said frame further comprises a front face, said front face is formed with a separate carrier protrusion aperture for each of said at least three carrier protrusions, and said front face is formed with at least three grooves, one of said at least three grooves between each adjacent pair of said carrier protrusion apertures. 
     
     
         8 . The carrier assembly of  claim 1 , wherein each of said at least three carrier protrusions is formed with a chamfer from said peripheral wall to said protrusion front face. 
     
     
         9 . The carrier assembly of  claim 1 , wherein each of said at least three carrier protrusions is formed with a step from said peripheral wall to said protrusion front face. 
     
     
         10 . The carrier assembly of  claim 9 , further comprising an elastic ring on said step formed on each of said at least three carrier protrusions. 
     
     
         11 . A carrier assembly, comprising:
 at least three carrier protrusions, each of said at least three carrier protrusions comprising a carrier protrusion front face;   at least three detachable rings, each of said at least three detachable rings surrounding a separate one of said at least three carrier protrusions;   at least three retaining rings, each of said at least three retaining rings surrounding a separate one of said at least three detachable rings; and   a base plate comprising:
 a base plate front face; and 
 at least three ring grooves formed in said base plate front face, each of said at least three ring grooves having a flat bottom surface parallel to said carrier protrusion front face on each of said at least three carrier protrusions, and each of said at least three ring grooves surrounding a separate one of said at least three carrier protrusions, thereby separating said base plate front face from each of said carrier protrusion front face. 
   
     
     
         12 . The carrier assembly of  claim 11 , wherein each of said at least three detachable rings comprises a flange and said at least three retaining rings hold said flange for each of said at least three detachable rings against said flat bottom surface in each of said at least three ring grooves. 
     
     
         13 . The carrier assembly of  claim 11 , wherein said carrier protrusion face on each of said at least three carrier protrusions has a perimeter shape corresponding to a perimeter shape of a wafer to be polished. 
     
     
         14 . The carrier assembly of  claim 11 , consisting of:
 five of said at least three carrier protrusions;   five of said at least three detachable rings; and   five of said at least three retaining rings.   
     
     
         15 . The carrier assembly of  claim 11 , wherein each of said at least three rings further comprises:
 an inner wall;   an outer wall; and   a plurality of transverse grooves from said inner wall to said outer wall.   
     
     
         16 . The carrier assembly of  claim 11 , wherein said carrier protrusion front face on each of said at least three carrier protrusions is formed with a chamfer all the way around said carrier protrusion front face. 
     
     
         17 . The carrier assembly of  claim 16 , wherein an acute angle between said chamfer and said carrier protrusion front face on each of said at least three carrier protrusions is in a range from 0.02 degrees to 5 degrees. 
     
     
         18 . The carrier assembly of  claim 11 , wherein each of said at least three carrier protrusions is formed with a step. 
     
     
         19 . The carrier assembly of  claim 18 , wherein each of said at least three carrier protrusions further comprises an elastic ring positioned on said step. 
     
     
         20 . The carrier assembly of  claim 18 , wherein a height dimension of said step formed on each of said at least three carrier protrusions is selected to cause a selected magnitude of deflection of a part of a wafer surface toward said base plate during wafer polishing.