Composite retaining ring
A two part retaining ring is described that has a lower ring and an upper ring. The lower ring contacts a polishing surface during chemical mechanical polishing. The upper surface and the lower surface of the lower ring have thick and thin subportions to increase the flexibility of the lower ring.
1. A retaining ring for chemical mechanical polishing of a substrate, comprising an annular portion, wherein the annular portion has a plurality of relatively thick subportions and a plurality of relatively thin subportions, wherein the relatively thick subportions and the relatively thin subportions extend from an inner diameter of the annular portion to an outer diameter of the annular portion of the retaining ring and top and bottom surfaces of the thin subportions are not co-planar with top and bottom surfaces of the thick subportions.
2. The retaining ring of claim 1 , wherein the annular portion is a first annular portion and the ring further comprises a second annular portion.
3. The retaining ring of claim 2 , wherein the second annular portion is more rigid than the first annular portion.
4. The retaining ring of claim 2 , wherein the second annular portion is secured to the first annular portion, forming apertures between the thin subportions and the second annular portion.
5. A method of making a retaining ring, comprising forming a first annular portion having a plurality of relatively thick subportions and a plurality of relatively thin subportions, wherein the relatively thick subportions and the relatively thin subportions extend from an inner diameter of the annular portion to an outer diameter of the annular portion of the retaining ring and top and bottom surfaces of the thin subportions are not co-planar with top and bottom surfaces of the thick subportions.
6. The method of claim 5 , wherein forming the first annular portion includes machining upper surface grooves and lower surface grooves into the first annular portion.
7. The method of claim 5 , further comprising:
forming a second annular portion; and
securing a lower surface of the second annular portion to an upper surface of the first annular portion.
8. The method of claim 7 , wherein securing the second annular portion to the first annular portion includes adhering the portions together.
9. The method of claim 5 , wherein forming the first annular portion includes injection molding a plastic material.
10. A method of making a retaining ring, comprising forming a first annular portion having an upper surface with a plurality of upper surface grooves and a lower surface with a plurality of lower surface grooves, wherein locations of the upper surface grooves in the upper surface substantially correspond to locations of the lower surface grooves in the lower surface and the upper surface grooves and the lower surface grooves extend from an inner diameter of the annular portion of the retaining ring to an outer diameter of the annular portion.
11. The method of claim 10 , wherein forming the first annular portion includes machining the upper surface grooves and lower surface grooves into the first annular portion.
12. The method of claim 10 , further comprising:
forming a second annular portion; and
securing a lower surface of the second annular portion to an upper surface of the first annular portion.
13. The method of claim 12 , wherein securing the second annular portion to the first annular portion includes adhering the portions together.
14. The method of claim 10 , wherein forming the first annular portion includes injection molding a plastic material.