CMP retaining ring with soft retaining ring insert
View Patent ↗A method of polishing a wafer with 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 method of polishing a wafer in a CMP process, said method comprising the steps of:
providing 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;
placing a wafer below the wafer mounting plate; and
rotating the wafer carrier over a polishing pad to polish a surface of the wafer.
2. A method of polishing a wafer in a CMP process, said method comprising the steps of:
providing 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;
placing a wafer below the wafer mounting plate; and
rotating the wafer carrier over a polishing pad to polish a surface of the wafer.
3. The method of claim 2 , wherein the inner ring comprises a material having a hardness of about 39 Shore D.
4. The method of claim 2 , wherein the first outer ring comprises PEEK, PET or polycarbonate, and the inner ring comprises polyurethane.
5. A method of polishing a wafer in a CMP process, said method comprising the steps of:
providing 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;
placing a wafer below the wafer mounting plate; and
rotating the wafer carrier over a polishing pad to polish a surface of the wafer.
6. A method of polishing a wafer in a CMP process, said method comprising the steps of:
providing 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;
placing a wafer below the wafer mounting plate; and
rotating the wafer carrier over a polishing pad to polish a surface of the wafer.
7. The method of claim 6 , wherein the inner radial portion comprises a material having a hardness of about 39 Shore D.
8. The method of claim 6 , wherein: the first outer ring comprises PEEK, PET or polycarbonate, and the inner ring comprises polyurethane.