Patent ID: 11890715
Assignee: APPLIED MATERIALS, INC.
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 8:
9. A carrier head for holding a substrate in a polishing system, comprising:
a housing;
a first flexible membrane secured to the housing to form one or more pressurizable chambers, the first flexible membrane having a central membrane section having a lower surface to control pressure on a central portion of a substrate;
a plurality of independently operable piezoelectric actuators supported by the housing, the plurality of piezoelectric actuators positioned radially outward of the first flexible membrane and at different angular positions; and
an edge control ring that is more rigid than the first flexible membrane, wherein the edge control ring is a separate piece coupled to and extending below and spanning the plurality of piezoelectric actuators such that the plurality of piezoelectric actuators control a tilt of the edge control ring as a whole relative to the housing, the edge control ring positioned to apply pressure to an annular region on the substrate surrounding the central portion of the substrate.