Patent ID: 9539696
Date: 2017-01-10
CPC Classifications: B24B

Claim:
1. A retainer ring configured to be attachable, at a first side thereof, to a polish head of a polish apparatus configured to polish a polish object by depressing the polish object against a polish pad, the retainer ring configured to depress the polish pad at a second side thereof, the retainer ring comprising: a contact surface configured to contact the polish pad, the contact surface configured to apply depressing force on the polish pad, the depressing force being directed from a polish head side and being applied so as to be centered on an imaginary circle of pressure center having a radius falling substantially in a middle of an inner radius of the retainer ring and an outer radius of the retainer ring, two or more concentric grooves being provided on the contact surface so that a count of the concentric grooves is greater in a second region outside the circle of pressure center than in a first region inside the circle of pressure center, and an area of the contact surface being greater in the first region inside the circle of pressure center than in the second region outside the circle of pressure center.