Patent ID: RE43837

Claim:
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.