CPC B24B 37/32 (2013.01) [Y10T 156/10 (2015.01)] | 5 Claims |
1. A retaining ring of a carrier head of a polishing apparatus, the retaining ring comprising:
an annular lower portion of a first material, the lower portion having a lower surface to contact a polishing pad; and an annular upper portion of a different second material, the upper portion having an upper surface configured to attach to the carrier head, wherein the lower portion is bonded to the upper portion by a bonding layer along an interface between the lower portion and the upper portion, wherein the interface includes a step adjacent to the inner diameter of the retaining ring and wherein a remainder of the interface between the step and the outer diameter of the retaining ring is flat with the bonding layer having uniform thickness.
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