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

Claim 14:
15. A polishing system, comprising:
a platen to support a polishing pad;
a drive shaft;
a carrier head for holding a substrate in the polishing system, the carrier head including
a housing secured to and moveable by the drive shaft,
a plurality of independently operable piezoelectric actuators supported by the housing, the plurality of piezoelectric actuators independently controllable,
an edge control ring positioned to apply pressure to an edge portion of the substrate, wherein the edge control ring is a separate piece extending below and spanning and coupled to 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; and

a control system configured to control voltages applied to the plurality of piezoelectric actuators such that a position at which a highest pressure is applied to the edge portion of a back surface of the substrate undergoes precession in conjunction with precession of the substrate in the carrier head.