Patent ID: 11890717
Assignee: APPLIED MATERIALS, INC.
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 12:
13. The polishing system of claim 1, further comprising:
an aperture in the top surface of the platen that overlaps the center of the platen;
a second annular flange projecting radially inward from the platen into the aperture to support an inner polishing pad, the second annular flange having an outer edge secured to and rotatable with the platen and vertically fixed relative to the top surface of the platen, the second annular flange being vertically deflectable such that an inner edge of the second annular flange is vertically movable relative to the outer edge; and
a second actuator configured to apply pressure to an underside of the second annular flange in an angularly limited region such that an angularly limited section of the second annular flange and an angularly limited portion of the inner polishing pad are lifted relative to the platen, an undeformed portion of the annular flange, and main polishing pad.