Magnetically secured retaining ring
A retaining ring having a bottom portion that is removable from the ring's upper portion is described. The upper and lower portions of the retaining ring include one or more magnetic bodies and/or one or more bodies formed of a material that is attracted to magnets.
1. A retaining ring, comprising:
a substantially annual upper portion having an upper surface configured to be attached to a carrier head;
a substantially annular lower portion having an upper surface configured to contact a lower surface of the upper portion;
wherein at least one of the upper portion or the lower portion includes a magnetic material; and
the other of the upper portion or the lower portion includes a material attracted to the magnetic material and is sufficiently attracted to the magnetic material to hold the upper portion and lower portion together.
2. The retaining ring of claim 1 , wherein:
the upper portion includes one or more alignment members extending from the lower surface; and
the lower portion includes one or more corresponding receiving recesses for the one or more alignment members.
3. The retaining ring of claim 1 , wherein:
the lower portion includes one or more alignment members extending from the lower surface; and
the upper portion includes one or more corresponding receiving recesses for the one or more alignment members.
4. The retaining ring of claim 1 , wherein the upper portion includes ferritic stainless steel.
5. The retaining ring of claim 1 , wherein the magnetic material is a permanent magnet.
6. The retaining ring of claim 1 , wherein the lower portion is less rigid than the upper portion.
7. The retaining ring of claim 1 , wherein the lower portion is formed from PPS.
8. The retaining ring of claim 7 , wherein the lower portion has magnets embedded in the PPS.
9. A method of forming a retaining ring, comprising:
forming a substantially annular lower portion of the retaining ring;
embedding one or more bodies of magnetic material in the lower portion; and
forming a substantially annular upper portion of the retaining ring such that at least a lower subportion of the upper portion includes a material that is capable of being attracted to the magnetic material when the upper portion is brought into contact with the lower portion.
10. The method of claim 9 , wherein forming the upper portion includes forming the upper portion to include ferritic stainless steel.
11. The method of claim 9 , wherein forming the upper portion includes forming one or more alignment members in the lower surface of the upper portion.
12. The method of claim 11 , wherein forming the lower portion includes forming in an upper surface one or more corresponding receiving recesses for the one or more alignment members in the upper portion.
13. The method of claim 9 , wherein forming the lower portion includes forming the lower portion from PPS.
14. The method of claim 9 , wherein embedding the one or more portions of magnetic material includes embedding permanent magnets into an upper surface of the lower portion.
15. A method of forming a retaining ring, comprising:
forming a substantially annular upper portion of the retaining ring such that one or more bodies of magnetic material are embedded in the upper portion;
forming a substantially annular lower portion of the retaining ring; and
bonding a material that is capable of being attracted to the magnetic material to an upper surface of the lower portion such that the magnetic material in the upper portion is capable of holding the lower portion and the upper portion together.
16. A method of attaching a retaining ring to a carrier head, comprising:
fastening an upper portion of the retaining ring to the carrier head, wherein the upper portion includes a material that is capable of being attracted to a magnetic material in a lower portion; and
bringing the lower portion of the retaining ring into contact with the upper portion, wherein one or more bodies of the magnetic material in the lower portion hold the upper portion and lower portion together.
17. The method of claim 16 , further comprising aligning the lower portion to the upper portion such that alignment members in the upper portion align with receiving recesses in the lower portion.
18. The method of claim 16 , further comprising, prior to bringing the lower portion into contact with the upper portion, aligning the upper portion with the carrier head so that the lower surface is perpendicular to a central axis of the carrier head.
19. A system for chemical mechanical polishing of a substrate, comprising:
a carrier head; and
a retaining ring secured to the carrier head, comprising:
a substantially annual upper portion having an upper surface configured to be attached to the carrier head;
a substantially annular lower portion having an upper surface configured to contact a lower surface of the upper portion;
wherein at least one of the upper portion or the lower portion includes a magnetic material; and
the other of the upper portion or the lower portion includes a material attracted to the magnetic material and is sufficiently attracted to the magnetic material to hold the upper and lower portions together.