Substrate supporting apparatus

Abstract

A substrate supporting apparatus includes a plate member of an aluminum alloy having a flat upper surface, bottomed pits formed in the plate member, and spacer members held in the pits, individually. The spacer members are sapphire spheres. The diameter of each spacer member is a little smaller than that of each pit. The upper end of each spacer member projects from the upper surface of the plate member. A spot facing is formed in a region that includes the open edge portion of the pit. A bending portion which is obtained by plastically deforming the open edge portion of the pit toward the spacer member is formed on a bottom surface of the spot facing. A V-shaped groove is formed behind the bending portion.

1. A substrate supporting apparatus comprising:
 a metallic plate member having a flat upper surface; and a plurality of spacer arrangement portions provided at the upper surface of the plate member to support a substrate; wherein each of the spacer arrangement portion portions comprises: 
 a pit formed in the upper surface of the plate member and having a circular open edge portion and a bottom, wherein the open edge portion and the bottom of the pit are integrally formed with the plate member as one piece; 
 a spacer member which has a diameter smaller than an inside diameter of the pit, and which is held in the pit and has an upper end projecting from the upper surface of the plate member; 
 a bending portion which is formed by plastically deforming the open edge portion of the pit toward the spacer member so that an opening width of the open edge portion of the pit is smaller than the diameter of the spacer member, wherein the bending portion and the plate member are integrally formed as one piece; and 
 a groove formed in the plate member and located behind the bending portion so as to extend along a circumferential direction of the open edge portion of the pit; 
 wherein the groove has a V-shaped cross section, and the groove and the bending portion are arranged individually in continuous rings covering an entire circumference of the open edge portion; 
 wherein a spot facing is formed on a part of the upper surface of the plate member which surrounds the open edge portion of the pit, and wherein the bending portion and the groove are formed on a bottom surface of the spot facing; and 
 wherein an inner bump and an outer bump are formed around the groove of the bottom surface of the spot facing, wherein the inner bump is raised higher than the outer bump, and wherein the bumps are confined to positions lower than the upper surface of the plate member. 
 
     
     
       2. A substrate supporting apparatus according to  claim 1 , wherein the spacer member is a sphere of aluminum oxide, and the plate member is formed of an aluminum alloy. 
     
     
       3. A substrate supporting apparatus according to  claim 1 , wherein the spacer member is a sphere of a ceramic material, and the plate member is formed of an aluminum alloy. 
     
     
       4. A substrate supporting apparatus comprising:
 a metallic plate member having a flat upper surface; and   a plurality of spacer arrangement portions provided at the upper surface of the plate member to support a substrate;   wherein each of the spacer arrangement portions comprises:   a pit formed in the upper surface of the plate member and having a circular open edge portion and a bottom, wherein the open edge portion and the bottom of the pit are integrally formed with the plate member as one piece;   a spacer member which has a diameter smaller than an inside diameter of the pit, and which is held in the pit and has an upper end projecting from the upper surface of the plate member;   a bending portion which is formed by plastically deforming the open edge portion of the pit toward the spacer member so that an opening width of the open edge portion of the pit is smaller than the diameter of the spacer member, wherein the bending portion and the plate member are integrally formed as one piece; and   a groove formed in the plate member and located behind the bending portion so as to extend along a circumferential direction of the open edge portion of the pit;   wherein the groove has a V-shaped cross section, and the groove and the bending portion are arranged individually in part on rings covering an entire circumference of the open edge portion;   wherein a spot facing is formed on a part of the upper surface of the plate member which surrounds the open edge portion of the pit, and wherein the bending portion and the groove are formed on a bottom surface of the spot facing; and   wherein an inner bump and an outer bump are formed around the groove of the bottom surface of the spot facing, wherein the inner bump is raised higher than the outer bump, and wherein the bumps are confined to positions lower than the upper surface of the plate member.   
     
     
       5. A substrate supporting apparatus comprising:
 a metallic plate member having a flat upper surface; and   a plurality of spacer arrangement portions provided at the upper surface of the plate member to support a substrate;   wherein each of the spacer arrangement portions comprises:   a pit formed in the upper surface of the plate member and having a circular open edge portion and a bottom, wherein the open edge portion and the bottom of the pit are integrally formed with the plate member as one piece;   a spacer member which is a sphere and has a diameter smaller than an inside diameter of the pit, and which is held in the pit and has an upper end projecting from the upper surface of the plate member;   a bending portion which is formed by plastically deforming the open edge portion of the pit toward the spacer member so that an opening width of the open edge portion of the pit is smaller than the diameter of the spacer member, wherein the bending portion and the plate member are integrally formed as one piece, and the bending portion is configured to prevent the spacer member from slipping out of the pit;   a gap which is defined between a circumference of the sphere spacer member and the bending portion; and   a groove formed in the plate member and located behind the bending portion so as to extend along a circumferential direction of the open edge portion of the pit;   wherein the groove has a V-shaped cross section, and the groove and the bending portion are arranged individually in part on rings covering an entire circumference of the open edge portion;   wherein a spot facing is formed on a part of the upper surface of the plate member which surrounds the open edge portion of the pit, and wherein the bending portion and the groove are formed on a bottom surface of the spot facing; and   wherein an inner bump and an outer bump are formed around the groove of the bottom surface of the spot facing, wherein the inner bump is raised higher than the outer bump, and wherein the bumps are confined to positions lower than the upper surface of the plate member.