Carrier head with a flexible membrane

A carrier head for a chemical mechanical polishing apparatus, comprising:

• a base;
• and
• a substrate backing assembly connected to the base, wherein the substrate backing assembly has a first pressure applying area for applying a first pressure to a first region of a substrate held by the substrate backing assembly and a second pressure applying area for applying a second pressure to a second region of the substrate held by the substrate backing assembly, the second pressure applying area surrounding the first pressure applying area, wherein the first pressure is independent from the second pressure.

A method of assembling a carrier head for chemical mechanical polishing, comprising:

• clamping a flexible membrane to a support structure;
• and
• coupling the support structure to a base so that a portion of the flexible membrane is between the support structure and the base.

A retaining ring, comprising an annular body having an inner surface, an outer surface, a lower surface, and a passage through the annular body that extends from the inner surface to the outer surface and that is spaced apart from the lower surface.

A method of assembling a carrier head for chemical mechanical polishing, comprising:

• positioning an outer edge portion of flexible member of a substrate backing assembly between a base of the carrier head and a retaining ring of the carrier head;
• and
• securing the retaining ring to the base such that the outer edge portion is clamped between the base and the retaining ring and a portion of the retaining ring directly contacts the base.