Patent ID: 7897007

Claim:
An elastic membrane for use in a substrate polishing apparatus, the elastic membrane comprising: an outer circumferential portion; and a lower surface for holding a substrate thereon, the lower surface having a plurality of through-holes formed therein for holding the substrate, such that, when a vacuum force is applied to the through-holes, the substrate is held to the lower surface of the elastic membrane, wherein respective through-holes of the plurality of through holes expose respective communication holes of a support member adapted to hold the outer circumferential portion of the elastic membrane, wherein the vacuum force is applied to the respective through-holes via the exposed communication holes, such that the vacuum force continues to be applied via the exposed communication holes and a lower end surface of the support member becomes substantially flush with the lower surface of the elastic membrane, while the substrate is held to the lower surface of the elastic membrane, and wherein a pressure from a pressurized fluid is applied to an upper surface of the elastic membrane so as to uniformly press the substrate against a polishing surface of the substrate polishing apparatus when the substrate polishing apparatus is polishing the substrate.