Patent ID: 7727055

Claim:
A flexible membrane, comprising: a main portion with a lower surface to provide a substrate-mounting surface; an outer annular portion extending from the outer edge of the main portion; and a plurality of concentric annular flaps connected to the main portion to divide a volume above the main portion into a plurality of chambers when the flexible membrane is secured to a carrier head; wherein a first of the plurality of concentric annular flaps includes a laterally extending section and a vertically extending section connecting the laterally extending section to the main portion and a second of the plurality of concentric annular flaps includes a laterally extending section and a diagonally extending section connecting the laterally extending section to the main portion; and wherein a juncture between the main portion and the outer annular portion comprises a peripheral edge hinge and an annular recess above the hinge along the outer wall of the outer annular portion, the peripheral edge hinge having rounded inner and outer surfaces and configured to be compliant.