Patent ID: 11958163
Assignee: EBARA CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC B  H | IPC B  H

Claim 13:
14. An elastic membrane for use in a substrate holding apparatus, comprising:
a contact portion to be brought into contact with a substrate for pressing the substrate against a polishing pad;
an edge circumferential wall extending upwardly from a peripheral edge of the contact portion; and
a plurality of inner circumferential walls arranged radially inwardly of the edge circumferential wall and extending upwardly from the contact portion,
wherein at least two adjacent inner circumferential walls of the plurality of inner circumferential walls comprise slope circumferential walls inclined radially inwardly;
the slope circumferential walls are inclined radially inwardly in their entirety from their lower ends to upper ends, and extend upwardly, and
wherein, when the elastic membrane is viewed in a vertical cross-section, at least a part of the slope circumferential wall located radially outward, of the adjacent inclined peripheral walls is located above the slope circumferential wall located radially inward, of the adjacent inclined peripheral walls.