Separation of plasma suppression and wafer edge to improve edge film thickness uniformity

Abstract

A carrier wafer for receiving a wafer and supporting the wafer during semiconductor processing operations. The carrier wafer includes an annular ring surface and a pocket, the pocket being defined in a center of the carrier wafer and including a step defined by a sidewall extending between the annular ring surface and a top surface of the pocket.

What is claimed is: 
     
         1 . A carrier wafer for receiving a wafer of diameter D and thickness T and supporting the wafer during semiconductor processing operations, the carrier wafer including an annular ring surface and a pocket, the pocket being defined in a center of the carrier wafer and including a step, the annular ring surface being defined to surround the pocket and extend from a top edge of the step to an outer edge of the carrier wafer, the step including a top surface that corresponds to the annular ring surface, a bottom surface that corresponds to a top surface of the pocket, and a sidewall that extends between the top surface and the bottom surface of the step, wherein the top surface of the pocket extends across a circular region bounded by the sidewall and provides a support surface for receiving the semiconductor wafer, a diameter of the pocket is sized larger than the diameter D, and the annular ring surface of the carrier wafer, and the carrier wafer are a single, contiguous structure. 
     
     
         2 . The carrier wafer of  claim 1 , wherein:
 an inner diameter of the annular ring surface is smaller than a diameter of the top surface of the pocket, and   the sidewall is at an oblique angle with respect to the top surface of the pocket.   
     
     
         3 . The carrier wafer of  claim 2 , wherein an intersection between the sidewall and the annular ring surface is rounded. 
     
     
         4 . The carrier wafer of  claim 2 , wherein an intersection between the sidewall and the top surface of the pocket is rounded. 
     
     
         5 . The carrier wafer of  claim 2 , wherein:
 an intersection between the sidewall and the top surface of the pocket is rounded, and   an intersection between the sidewall and the top surface of the pocket is rounded.   
     
     
         6 . The carrier wafer of  claim 2 , wherein the carrier wafer further comprises a plurality of support structures distributed across the top surface of the carrier wafer, each support structure protruding from the top surface of the carrier wafer. 
     
     
         7 . The carrier wafer of  claim 7 , wherein a normal distance between a reference plane coincident with the annular ring surface and surfaces of the support structures closest to the reference plane is substantially equal to the thickness T of the wafer. 
     
     
         8 . The carrier wafer of  claim 1 , wherein:
 an inner diameter of the annular ring surface is larger than a diameter of the top surface of the pocket, and   the sidewall is at an oblique angle with respect to the top surface of the pocket.   
     
     
         9 . The carrier wafer of  claim 8 , wherein an intersection between the sidewall and the annular ring surface is rounded. 
     
     
         10 . The carrier wafer of  claim 8 , wherein an intersection between the sidewall and the top surface of the pocket is rounded. 
     
     
         12 . The carrier wafer of  claim 8 , wherein:
 an intersection between the sidewall and the top surface of the pocket is rounded, and   an intersection between the sidewall and the top surface of the pocket is rounded.   
     
     
         13 . The carrier wafer of  claim 8 , wherein the carrier wafer further comprises a plurality of support structures distributed across the top surface of the carrier wafer, each support structure protruding from the top surface of the carrier wafer. 
     
     
         14 . The carrier wafer of  claim 13 , wherein a normal distance between a reference plane coincident with the annular ring surface and surfaces of the support structures closest to the reference plane is substantially equal to the thickness T of the wafer. 
     
     
         15 . The carrier wafer of  claim 1 , wherein the sidewall is perpendicular to the top surface of the pocket. 
     
     
         16 . The carrier wafer of  claim 15 , wherein an intersection between the sidewall and the annular ring surface is rounded. 
     
     
         17 . The carrier wafer of  claim 15 , wherein an intersection between the sidewall and the top surface of the pocket is rounded. 
     
     
         18 . The carrier wafer of  claim 15 , wherein:
 an intersection between the sidewall and the top surface of the pocket is rounded, and   an intersection between the sidewall and the top surface of the pocket is rounded.   
     
     
         19 . The carrier wafer of  claim 15 , wherein the carrier wafer further comprises a plurality of support structures distributed across the top surface of the carrier wafer, each support structure protruding from the top surface of the carrier wafer. 
     
     
         20 . The carrier wafer of  claim 19 , wherein a normal distance between a reference plane coincident with the annular ring surface and surfaces of the support structures closest to the reference plane is substantially equal to the thickness T of the wafer.