Retaining ring with selected stiffness and thickness
AssigneeApplied Materials, Inc.
InventorsHung Chih Chen, Samuel Chu-Chiang Hsu, Gautam Shashank Dandavate
Life of this patent
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Abstract
A retaining ring for holding a substrate below a carrier head during chemical mechanical polishing includes an annular lower portion and an annular upper portion secured to the lower portion. The annular lower portion has a main body with a bottom surface for contacting a polishing pad during polishing, and is a first material. A top surface of the upper portion is configured to be secured to the carrier head. The upper portion is a second material that is more rigid than the first material. A thickness and stiffness of the lower portion is selected for a particular polishing environment to improve polishing uniformity near an edge of the substrate.
Claims9
A method of selecting a retaining ring, comprising:
- polishing a first test substrate with the first test substrate held in a carrier head having a first retaining ring having an upper portion and a lower portion with a first stiffness and a first thickness;
- measuring polishing uniformity of the first test substrate;
- selecting based on the polishing uniformity a second retaining ring with an upper portion and a lower portion with a second stiffness and a second thickness;
- polishing a second test substrate with the second test substrate held in the carrier head having the second retaining ring;
- and
- polishing a plurality of device substrates using a plurality of carrier heads having a plurality of retaining rings, each retaining ring of the plurality of retaining rings having an upper portion and a lower portion with the second stiffness and the second thickness.
Dependencies are inferred from the claim text.