MULTILAYER RETAINING RING FOR CHEMICAL MECHANICAL POLISHING

摘要

A carrier head for a chemical mechanical polishing apparatus includes a retaining ring having a flexible lower portion and a rigid upper portion. A shim can be inserted between the retaining ring and a base of the carrier head to improve the retaining ring lifetime. A seal may be inserted between the retaining ring and a flexible membrane to seal the chamber between the flexible membrane and the base.