Polishing apparatus including separate retainer rings
AssigneeElpida Memory, Inc.
InventorToshiya Saito
Life of this patent
Estimating the term…
Abstract
A polishing apparatus includes a polishing pad for polishing a wafer and a polishing head for holding the wafer. The polishing head includes a retainer ring, a membrane sheet, and a head body. The retainer ring retains the wafer in a horizontal direction. The membrane sheet depresses the wafer to the polishing pad. The head body supports the retainer ring and the membrane sheet. The retainer ring includes a fixed retainer ring and a released retainer ring. The released retainer ring is interposed between the inner periphery of the fixed retainer ring and the periphery of the wafer to retain the wafer in the horizontal direction.
Claims5
A polishing apparatus comprising:
- a polishing pad configured to polish a wafer;
- and
- a polishing head configured to hold the wafer and said polishing head, said polishing head including a retainer ring for retaining the wafer in an in-plane direction of the wafer, a membrane sheet for depressing the wafer toward said polishing pad, and a head body supporting thereon said retainer ring and said membrane sheet, wherein:
- said retainer ring comprises a first member having a substantially ring shape, has inner diameter and thickness larger than outside diameter and thickness, respectively, of the wafer, and is depressed toward said polishing pad by said head body, and a second member having a thickness substantially equal to the thickness of the wafer, is interposed between an inner edge of said first member and a periphery of the wafer to retain the periphery of the wafer in the in-plane direction of the wafer;
- and
- said membrane sheet depresses the wafer and said second member toward said polishing pad.
Dependencies are inferred from the claim text.