CMP retaining ring with soft retaining ring insert
View Patent ↗A wafer carrier adapted to further reduce the edge effect and allow a wafer to be uniformly polished across its entire surface, with a retaining ring made from very hard materials such as PEEK, PET or polycarbonate with a hardness in the range of 80 to 85 Shore D, while the inner surface or insert is made of polyurethane or other material with a hardness in the range of 85 to 95 Shore A.
1. A wafer carrier comprising:
a carrier housing;
a wafer mounting plate disposed beneath the carrier housing;
a retaining ring assembly disposed about a lower portion of the wafer mounting plate, said retaining ring assembly comprising a first outer ring and a second, inner ring disposed coaxially within the first outer ring; wherein
the first outer ring comprises a material having a hardness in the range of 80 to 85 Shore D, and the inner ring comprises a material having a hardness in the range of 85 to 95 Shore A.
2. A wafer carrier comprising:
a carrier housing;
a wafer mounting plate disposed beneath the carrier housing;
a retaining ring assembly disposed about a lower portion of the wafer mounting plate, said retaining ring assembly comprising a first outer ring and a second, inner ring disposed coaxially within the first outer ring; wherein
the first outer ring comprises a material having a hardness in the range of 80 to 85 Shore D, and the inner ring comprises a material having a hardness in the range of 33 to 46 Shore D.
3. The wafer carrier of claim 2 , wherein:
the inner ring comprises a material having a hardness of about 39 Shore D.
4. The wafer carrier of claim 2 , wherein:
the first outer ring comprises PEEK, PET or polycarbonate, and the inner ring comprises polyurethane.
5. A wafer carrier comprising:
a carrier housing;
a wafer mounting plate disposed beneath the carrier housing;
a retaining ring disposed about a lower portion of the wafer mounting plate, said retaining ring characterized by an outer radial portion and an inner radial portion; wherein:
the outer radial portion comprises a material having a hardness in the range of 80 to 85 Shore D, and the inner radial portion comprises a material having a hardness in the range of 85 to 95 Shore A.
6. A wafer carrier comprising:
a carrier housing;
a wafer mounting plate disposed beneath the carrier housing;
a retaining ring disposed about a lower portion of the wafer mounting plate, said retaining ring characterized by an outer radial portion and an inner radial portion; wherein:
the outer radial portion comprises a material having a hardness in the range of 80 to 85 Shore D, and the inner radial portion comprises a material having a hardness in the range of 33 to 46 Shore D.
7. The wafer carrier of claim 6 , wherein:
the inner radial portion comprises a material having a hardness of about 39 Shore D.
8. The wafer carrier of claim 6 , wherein:
the first outer ring comprises PEEK, PET or polycarbonate, and the inner ring comprises polyurethane.