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Title:
CHEMICAL MECHANICAL POLISHING HEAD HAVING FLOATING WAFER RETAINING RING AND WAFER CARRIER WITH MULTI-ZONE POLISHING PRESSURE CONTROL
Document Type and Number:
WIPO Patent Application WO/2000/054933
Kind Code:
A2
Abstract:
In one aspect the invention provides a polishing apparatus (101) including a housing (120) a carrier (160) for mounting a substrate (113) to be polished, a retaining ring (134) circumscribing the carrier (113) for retaining the substrate (113), a first coupling (162) attaching the retaining ring (134) to the carrier (160) such that the retaining ring (134) may move relative to the carrier (160), a second coupling (145) attaching the carrier (160) to the housing (120) the housing (120) and the first coupling (162) defining a first pressure chamber (131) to exert a pressure force against the retaining ring (134), and the housing (120) and the second coupling (145) defining a second pressure chamber (132) to exert a pressure force against the subcarrier (160). In one embodiment, the couplings are diaphragms. In another embodiment, the invention includes a single- or multiple-chambered wafer carrier or subcarrier capable of modifying a differential polishing pressure across the surface of the wafer or other substrate.

Inventors:
Wang, Huey-ming (34294 Quartz Terrace, Fremont, CA, 94555, US)
Moloney, Gerard S. (74 Washington Square Drive, Milpitas, CA, 95035, US)
Chin, Scott (473 Pepper Drive, Palo Alto, CA, 94306, US)
Geraghty, John J. (1029 El Camino Real #8, Burlingame, CA, 94010, US)
Dyson Jr., William (6912 Bollinger Road, San Jose, CA, 95129, US)
Dickey, Tanlin K. (1063 Morse Avenue #5-205, Sunnyvale, CA, 92089, US)
Application Number:
PCT/IB2000/000508
Publication Date:
September 21, 2000
Filing Date:
February 24, 2000
Export Citation:
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Assignee:
MITSUBISHI MATERIALS CORPORATION (1-5-1 Ohtemchi, Chiyoda-ku, Tokyo, 100-8117, JP)
International Classes:
B24B37/30; B24B37/32; B24B41/06; B24B49/16; H01L21/304; (IPC1-7): B24B37/00
Foreign References:
EP0881039A21998-12-02
EP0548846A11993-06-30
US5584751A1996-12-17
GB2307342A1997-05-21
EP0791431A11997-08-27
GB2315694A1998-02-11
US5857899A1999-01-12
US5651724A1997-07-29
US4918869A1990-04-24
Download PDF:
Claims:
AMENDED CLAIMS [received by the International Bureau on 20 December 2000 (20.12.00); original claim 38 amended ; new claims 39-50 added; remaining claims unchanged (9 pages)]
1. A polishing apparatus comprising: a housing; a disc shaped carrier for mounting a substrate to be polished; a retaining ring substantially circumscribing said carrier for retaining said substrate in a pocket formed by said retaining ring and a surface of said carrier ; a first flexible coupling attaching said retaining ring to said carrier such that said retaining ring may translate in at least one dimension and tilt about an axis relative to said carrier ; a second flexible coupling attaching said carrier to said housing such that said carrier may translate in at least one dimension and tilt about an axis relative to said housing ; said housing and said first flexible coupling defining a first chamber in fluid communication with a first source of pressurized gas such that when gas at a first pressure is communicated to said first chamber a first force is exerted against said retaining ring ; and said housing and said second flexible coupling defining a second chamber in fluid communication with a second source of pressurized gas such that when gas at a second pressure is communicated to said second chamber a second force is exerted against said subcarrier.
2. The polishing apparatus in Claim 1. wherein said translation and tilt of said carrier is independent of said translation and tilt of said retaining ring.
3. The polishing apparatus in Claim 1, wherein said translation and tilt of said carrier is coupled to a predetermined extent with said translation and tilt of said retaining ring.
4. The polishing apparatus in Claim 1, wherein said translation and tilt of said earner and said translation and tilt of said retaining ring each have a component that is independent of the other and a component that is dependent on the other.
Description:
5. The polishing apparatus in Claim 4, wherein the extent to which said translation and tilt components of said carrier and said ring are coupled is dependent on material characteristics of said first and second flexible couplings and geometry characteristics of said attachments.

6. The polishing apparatus in Claim 5, wherein said material characteristics that affect the extent of coupling include elasticity, stiffness, and spring constant; and said geometry characteristics include distance between attachment locations between said ring and said carrier and distance between attachment locations between said carrier and said housing ; the geometry of the interface between said first and second diaphragms and adjacent structures of said housing, said retaining ring, and said carrier.

7. The polishing apparatus in Claim 1, wherein said first pressure and said second pressure are different pressures.

8. The polishing apparatus in Claim 1, wherein said first pressure and said second pressure are substantially equal pressures.

9. The polishing apparatus in Claim 1, wherein said first pressure and said second pressure are substantially equal pressures and the force exerted on said retaining ring and on said carrier are determined by the surface area of said retaining ring and said carrier over which each said pressure is applied.

10. The polishing apparatus in Claim 1, wherein said first pressure and said second pressure may independently be positive pressure or negative pressure (vacuum).

11. The polishing apparatus in Claim 10, wherein the depth of a pocket formed by a surface of said carrier and an inner cylindrical surface of said retaining ring is established during a substrate loading phase by said first pressure and said second pressure.

12. The polishing apparatus in Claim 1, wherein said substrate comprises a semiconductor wafer.

13. The polishing apparatus in Claim 1, wherein said retaining ring further comprises: a lower surface for contacting an external polishing pad during polishing; an inner cylindrical surface disposed adjacent to an outer circumferential surface of said carrier and the periphery of a substrate mounting surface of said carrier, said inner cylindrical surface and said carrier mounting surface periphery forming a pocket for maintaining said substrate during polishing; and a pad conditioning member disposed at the lower outer radial portion of said retaining ring where said retaining ring contacts said pad during polishing and defining a shape profile transitioning between a first planar surface substantially parallel to a plane of said polishing pad and a second planar surface substantially perpendicular to said polishing pad.

14. The polishing apparatus of Claim 13, wherein said pad conditioning member is characterized by presenting an angle substantially between 15 degrees and substantially 25 degrees out of parallel with respect to the nominal plane of said polishing pad.

15 The polishing apparatus of Claim 13, wherein said pad conditioning member is characterized by presenting an angle substantially between 18 degrees and substantially 22 degrees out of parallel with respect to the nominal plane of said polishing pad.

16. The polishing apparatus of Claim 13, wherein said pad conditioning member is characterized by presenting an angle substantially 20 degrees out of parallel with respect to the nominal plane of said polishing pad.

17-The polishing apparatus of Claim 13, wherein said pad conditioning member is characterized by presenting an angle substantially 20 degrees out of parallel with respect to the nominal plane of said polishing pad; and further characterized by presenting a second angle of substantially 70 degrees out of parallel with respect to the nominal plane of said polishing pad.

18. The polishing apparatus of Claim 13, further characterized in that said portion presenting a substantially 20 degree angle extends a distance of between 0.03 and 0.04 inches from said lower planar retaining ring surface, and said portion presenting a substantially 70 degree angle extends to at least a distance of about 0.2 inches from said lower planar retaining ring surface 19. The polishing apparatus of Claim 13, wherein said pad conditioning member is characterized by ; presenting an angle substantially between 15 degrees and substantially 25 degrees out of parallel with respect to a nominal plane of said polishing pad ; and presenting a second substantially between 65 degrees and substantially 75 degrees out of parallel with respect to said nominal plane of said polishing pad.

20. The polishing apparatus in Claim 1, wherein said first pressure on said carrier is in the range between substantially 1.5 psi and substantially 10 psi and the second pressure on said retaining ring is in the range between substantially 1.5 psi and substantially 9.0 psi.

21. The polishing apparatus in Claim 1, wherein said flexible coupling comprises a diaphragm.

22. The polishing apparatus in Claim 1, wherein said diaphragm is formed from a material selected from the group consisting of : metal, plastic, rubber, polymer, titanium, stainless-steel, carbon fibre composite, and combinations thereof 23. The polishing apparatus in Claim 1, wherein said carrier is formed from ceramic material.

24. A substrate retaining ring for a polishing machine, said retaining ring comprising: a lower surface for contacting an external polishing pad during polishing; an inner cylindrical surface disposed adjacent to an outer circumferential surface of said carrier and the periphery of a substrate mounting surface of said carrier,

said inner cylindrical surface and said carrier mounting surface periphery forming a pocket for maintaining said substrate during polishing; and a pad conditioning member disposed at the lower outer radial portion of said retaining ring where said retaining ring contacts said pad during polishing and defining a shape profile transitioning between a first planar surface substantially parallel to a plane of said polishing pad and a second planar surface substantially perpendicular to said polishing pad.

25. The substrate retaining ring of Claim 24, wherein said pad conditioning member is characterized by presenting an angle substantially between 15 degrees and substantially 25 degrees out of parallel with respect to the nominal plane of said polishing pad.

26. The polishing apparatus of Claim 24, wherein said pad conditioning member is characterized by presenting an angle substantially between 18 degrees and substantially 22 degrees out of parallel with respect to the nominal plane of said polishing pad.

27. The substrate retaining ring of Claim 24, wherein said pad conditioning member is characterized by presenting an angle substantially 20 degrees out of parallel with respect to the nominal plane of said polishing pad.

28. The substrate retaining ring of Claim 24, wherein said pad conditioning member is characterized by presenting an angle substantially 20 degrees out of parallel with respect to the nominal plane of said polishing pad; and further characterized by presenting a second angle of substantially 70 degrees out of parallel with respect to the nominal plane of said polishing pad.

29. The substrate retaining ring of Claim 24, further characterized in that said portion presenting a substantially 20 degree angle extends a distance of between 0.03 and 0.04 inches from said lower planarBretaining ring surface, and said portion. presenting a substantially 70 degree angle extends to at least a distance of a't 0. 2 ° inches from said lower planar retaining ring surface

30-The substrate retaining ring of Claim 24, wherein said pad conditioning member is characterized by: presenting an angle substantially between 15 degrees and substantially 25 degrees out of parallel with respect to a nominal plane of said polishing pad ; and presenting a second substantially between 65 degrees and substantially 75 degrees out of parallel with respect to said nominal plane of said polishing pad.

31. A method of planarizing a semiconductor wafer, said method including: supporting a back-side surface of said wafer with a wafer support subcarrier, applying a polishing force against said support subcarrier to press a front surface of said wafer against a polishing pad; restraining movement of said wafer from said support subcarrier during polishing with a retaining ring circumferentially disposed around a portion of said subcarrier and said wafer; and applying a pad conditioning force against said retaining ring to press a front surface of said retaining ring against said polishing pad.

32. The method in Claim 31, wherein said pad conditioning force is applied independently of said polishing force.

33. The method in Claim 31, wherein said pad conditioning force is coupled to said polishing force.

34. The method in Claim 31, wherein said pad conditioning force is applied to a first area of said pad in a direction orthogonal to a plane defined by said pad surface, to a second area of said pad in a direction having a first fractional component orthogonal to said plane and having a second fractional component parallel to said plane.

35. An article of manufacture comprising a semiconductor wafer polished according to the method of Claim 31.

36. An article of manufacture comprising a semiconductor wafer planarized according to the method of Claim 34.

37. The polishing apparatus in Claim 1, wherein said disc shaped carrier further comprises: at least one cavity formed into a wafer mounting surface of said carrier ; a fluid communication channel extending from said at least one cavity to an external source of pressurize fluid; said wafer mounting surface adapted to receive a flexible membrane, said membrane covering said at least one cavity to form a third chamber capable of holding a pressure when said pressurized fluid is communicated from said external source of pressurized fluid to said at least one cavity; and said membrane expanding when said pressurized fluid is communicated to said third chamber and exerting a force on a wafer mounted between said membrane and an external polishing pad during polishing.

38. A semiconductor wafer carrier for holding a semiconductor wafer during a planarization operation, said wafer carrier comprising: a disk-shaped block of substantially non-porous material having a first surface for mounting said semiconductor wafer, a second surface, and a third substantially cylindrical surface connecting said first and second surfaces; said first surface being substantially planar except for at least one cavity extending over a first annular region having a first annular width near said third cylindrical surface to a first depth from said substantially planar first surface into an interior portion of said wafer carrier; a fluid communication channel extending from said cavity to either said second surface or to said third surface to communicate a pressurized fluid from an external source of pressurized fluid to said cavity; said first surface adapted to receive a flexible membrane to cover said cavity and form a chamber capable of holding a pressure when said pressurized fluid is communicated from said external source of pressurized fluid to said cavity ; and said membrane expanding when said pressurized fluid is communicated to said third chamber and exerting a force on said semiconductor wafer near an annular edge portion of said wafer mounted to said first surface and to said membrane.

39. The semiconductor wafer carrier of any of claims 38, wherein said third chamber defines an edge transition chamber and said force exerted by said edge transition chamber is applied only to an edge area of said semiconductor wafer.

40. The semiconductor wafer carrier of claim 38, wherein said first surface further including at least a second cavity extending over a second annular region having a second annular width near said third cylindrical surface to a second depth from said substantially planar first surface into an interior portion of said wafer carrier.

41 The semiconductor wafer carrier of claim 3S, wherein a volume of fluid injected into said third chamber is adjusted to control the amount of material removed from said wafer to achieve a more uniform planarized wafer surface.

42. The semiconductor wafer carrier of claim 38, wherein the pressure applied to said third chamber is adjusted to control the amount of material removed from said wafer to achieve a more uniform planarized wafer surface.

43. The semiconductor wafer carrier of claim 41 or 42, wherein said adjustment increases the amount of material removed from said edge region of said wafer.

44. The semiconductor wafer carrier of claim 41 or 42, wherein said adjustment decreases the amount of material removed from said edge region of said wafer.

45. The semiconductor wafer carrier of claim 40, wherein said first and said second cavity share a common pressure source.

46. The semiconductor wafer carrier of claim 40, wherein said first and said second cavity have different and substantially independent pressure sources.

47. The semiconductor wafer carrier of claim 40, wherein said first and said second cavities provide an adjustable polishing force profile and different material

removal rates to be provided at different radial distances from the center to the edge of the wafer.

48. The semiconductor wafer carrier of claim 40, wherein said cavity has dimensions of between about one-twenty-fifth of an inch and about one-tenth of an inch deep and between about one-tenth of an inch and one-half inch in width.

49. The semiconductor wafer carrier of claim 40, wherein said cavity has a depth of between substantially 1 mm and substantially 2 mm deep.

50. The semiconductor wafer carrier of claim 40, wherein said cavity has a depth of between substantially 0.5 mm and substantially 5 mm deep.