Method and apparatus for electrochemically depositing a material onto a workpiece surface

• US 6,572,755 B2
• Filed: 04/11/2001
• Issued: 06/03/2003
• Est. Priority Date: 04/11/2001
• Status: Expired due to Fees

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: SpeedFam-Ipec Corporation (Lam Research Corporation)
• Inventors: Mueller, Brian, Chadda, Saket, Emesh, Ismail, Korovin, Nikolay
• Primary Examiner(s): Valentine, Donald R.
• Application Number:
  US09/832,657
• Publication Number:
  US 20020148732A1
• Time in Patent Office: 783 Days
• Field of Search: 205/88, 205/137, 205/222, 205/224, 205/118, 204/224.R, 204/212, 204/198, 204/224.M
• US Class Current: 205/137
• CPC Class Codes: B23H 5/08 Electrolytic grinding
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 17/14 for pad-plating
• CPC Class Codes: C25D 5/06 Brush or pad plating
• CPC Class Codes: C25D 5/22 Electroplating combined with mechanical treatment during the deposition
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/67167 surrounding a central transfer chamber
• CPC Class Codes: H01L 21/67219 comprising at least one polishing chamber polishing apparatuses B24B
• CPC Class Codes: H01L 21/6723 comprising at least one plating chamber electroless plating apparatuses C23C, electroplating apparatuses C25D

Abstract

An electrochemical deposition apparatus and method for depositing a material onto a surface of a workpiece and for polishing the material are disclosed. The apparatus includes a platen and a polishing surface, including a conductive material and conductors embedded therein, disposed proximate the platen. During material deposition, a bias is applied across the conductor and the platen to cause deposition of material onto the workpiece surface.

Claims

1. An electrical deposition apparatus for depositing material onto a surface of a workpiece, said apparatus comprising:

a polishing surface;

a platen comprising conductive material, said platen disposed proximate said polishing surface;

at least one electrical conductor positioned within said polishing surface;

an electrolyte solution adapted to contact said polishing surface and the workpiece;

a workpiece carrier configured to carry the workpiece and press the workpiece against said polishing surface; and

a power supply coupled to said platen and said workpiece carrier;

wherein said power supply applies a bias across said platen and the surface of the workpiece, said bias sufficient to cause material from said electrolyte solution to deposit onto the surface of the workpiece.

2. The apparatus of claim 1, further comprising a contact element which is formed of low electrical resistance material and is connected to said at least one electrical conductor, wherein at least a portion of said contact element is positioned within said polishing surface.

3. The apparatus of claim 2, wherein said contact element is formed of at least one of conductively-enhanced polymer material, ceramic material and inorganic fibers.

4. The apparatus of claim 1, wherein said polishing surface is made of insulating material.

5. The apparatus of claim 1, wherein said polishing surface is porous.

6. The apparatus of claim 1, further comprising a solution application mechanism configured to supply said electrolyte solution to said polishing surface.

7. The apparatus of claim 6, wherein said solution application mechanism comprises at least one channel formed in said platen through which said electrolyte solution may flow.

8. The apparatus of claim 7, wherein said polishing surface includes at least one aperture through which said electrolyte solution from said at least one channel may flow.

9. The apparatus of claim 8, wherein said at least one aperture is configured to expose a portion of said platen to facilitate creation of said electric potential difference between said platen and the surface of the workpiece.

10. The apparatus of claim 1, wherein said polishing surface includes grooves configured to facilitate distribution of said electrolyte solution.

11. The apparatus of claim 1, wherein said polishing surface comprises windows configured to expose portions of said platen to facilitate creation of an electric field of said electric potential difference between said platen and the surface of the workpiece.

12. The apparatus of claim 1, wherein said workpiece carrier is configured to cause relative motion between said workpiece and said polishing surface.

13. The apparatus of claim 12, wherein said relative motion comprises orbital motion.

14. The apparatus of claim 1, wherein said platen is configured to move in an orbital pattern.

15. The apparatus of claim 1, wherein at least a portion of said platen comprises at least one of aluminum, titanium, gold, copper, tantalum and platinum.

16. The apparatus of claim 1, wherein said electrolyte solution comprises copper ions.

17. The apparatus of claim 1, wherein said workpiece carrier is configured to press the workpiece against said polishing surface at a pressure no greater than approximately 2 psi.

18. The apparatus of claim 1, further comprising at least a first group and a second group of electrical conductors, wherein said power source supplies a first current to said first group and a second current to said second group, said first current being different from said second current.

19. The apparatus of claim 1, wherein said electric potential difference alternates between a first electric potential difference and a second electric potential difference.

20. The apparatus of claim 19, wherein said first electric potential difference is zero.

21. The apparatus of claim 1, wherein said electrical potential difference is constant.

22. The apparatus of claim 1, further comprising a temperature control mechanism for counteracting the generation of heat at the surface during deposition.

23. The apparatus of claim 22, further comprising a solution application mechanism configured to supply an electrolyte solution to a surface of said polishing surface, wherein said temperature control mechanism comprises a chiller for cooling said electrolyte solution before said solution is applied to said polishing surface.

24. The apparatus of claim 22, wherein said workpiece carrier comprises a heat exchange fluid for regulating the temperature of the workpiece.

25. The apparatus of claim 1, wherein said platen comprises heat conductive material, wherein said platen is configured to be temperature controlled by a heat exchange fluid circulating therethrough.

26. The apparatus of claim 1, wherein a distance between said platen and the surface of the workpiece is not greater than approximately 3 mm.

27. The apparatus of claim 26, wherein said distance is no greater than approximately 1 mm.

28. The apparatus of claim 27, wherein said distance is no greater than approximately 2000 angstroms.

29. The apparatus of claim 1, wherein the polishing surface comprises a blown polyurethane polishing pad.

30. The apparatus of claim 1, further comprising an endpoint detection system configured to measure a thickness of a film deposited onto the workpiece surface.

31. A polishing system comprising the apparatus of claim 1.

32. The apparatus of claim 1, wherein the apparatus is configured to monitor a change in an electrical resistance across the workpiece as said material from said electrolyte solution is deposited onto the surface of the workpiece.

33. The apparatus of claim 32, wherein the apparatus is further configured to detect an endpoint of deposition of the material onto the surface of the workpiece.

34. A method of depositing a material onto a surface of a workpiece, the method comprising the steps of:

providing a polishing surface;

providing a platen comprising a conductive material, said platen disposed proximate said polishing surface;

providing at least one electrical conductor disposed within said polishing surface;

pressing said workpiece against said polishing surface while causing relative motion between said workpiece and said polishing surface;

supplying an electrolyte solution to said polishing surface; and

applying an electric potential difference between the surface of said workpiece and said platen.

35. The method of claim 34, wherein said electrolyte solution is supplied to said polishing surface through at least one channel formed in said platen.

36. The method of claim 34, wherein said relative motion comprises orbital motion.

37. The method of claim 34, further comprising moving said platen in an orbital pattern.

38. The method of claim 34, wherein said applying an electric potential difference step comprises applying a constant electric potential difference.

39. The method of claim 34, wherein said applying an electrical potential difference step comprises applying an electric potential difference which alternates between a first electric potential difference and a second electric potential difference.

40. The method of claim 39, wherein said first electric potential difference is zero.

41. The method of claim 34, wherein said pressing said workpiece against said polishing surface step comprises pressing said workpiece against said polishing pad at a pressure no greater than approximately 2 psi.

42. The method of claim 34, further comprising a step of providing at least a first group of electrical conductors embedded within said polishing surface and a second group of electrical conductors embedded within said polishing surface, wherein said first group is supplied with a first current and said second group is supplied with a second current.

43. The method of claim 34, further comprising the step of cooling said electrolyte solution before supplying said solution to said polishing surface.

44. The method of claim 34, wherein providing a platen step comprises providing a platen including heat conductive material through which a heat exchange fluid circulates.

45. The method of claim 34, further comprising circulating a heat exchange fluid proximate a surface of said workpiece to counteract the generation of heat at the surface of the workpiece.

46. The method of claim 34, further comprising, during said pressing step, maintaining a distance between said platen and the surface of no greater than 3 mm.

47. The method of claim 34, further comprising, during said pressing step, maintaining a distance between said platen and the surface of no greater than 1 mm.

48. The method of claim 34, further comprising, during said pressing step, maintaining a distance between said platen and the surface of no greater than 2000 angstroms.

49. The method of claim 34, wherein said supplying an electrolyte solution comprises supplying an electrolyte solution including copper ions.

50. The method of claim 34, further comprising monitoring a change in an electrical resistance across the workpiece during said applying an electric potential difference.

51. The method of claim 34 further comprising detecting an endpoint of deposition of the material onto the surface of the workpiece.

52. An apparatus for electrochemically depositing a material onto a surface of a workpiece, comprising:

a polishing surface;

an electrically conductive surface disposed proximate to said polishing surface;

at least one conducting element disposed within said polishing surface;

a workpiece carrier configured to press the workpiece against said polishing surface; and

a power source configured to apply an electric bias between the surface of the workpiece and said electrically conductive surface.

53. The apparatus of claim 52, further comprising at least one passage disposed in said polishing surface, wherein the surface of the workpiece and said electrically conductive surface are adapted to be in fluid communication through said passage when the workpiece is pressed against said polishing surface.

54. The apparatus of claim 52, wherein said electrically conductive surface comprises a surface of a polishing platen.

55. The apparatus of claim 54, further comprising a conduit disposed in said polishing platen.

56. The apparatus of claim 52, wherein said polishing surface comprises a plurality of grooves.

57. The apparatus of claim 56, further comprising at least one fluid passage disposed in said polishing surface, wherein said at least one fluid passage is in fluid communication with at least one of said plurality of grooves.

58. The apparatus of claim 57, wherein said electrically conductive surface comprises a polishing platen having at least one conduit positioned therethrough, and wherein said at least one conduit is in fluid communication with said at least one fluid passage.

59. The apparatus of claim 52, further comprising a contact element formed of low electrical resistance material connected to said conducting element, wherein said contact element is in electrical communication with said conducting element and the surface of the workpiece.

60. The apparatus of claim 52, wherein said workpiece carrier is configured to cause relative motion between said workpiece and said polishing surface.

61. A multi-station polishing system including the apparatus of claim 52.

62. The apparatus of claim 52, wherein the apparatus is configured to monitor a change in an electrical resistance across the workpiece during depositing of the material onto the surface of the workpiece.

63. The apparatus of claim 62, wherein the apparatus is further configured to detect an endpoint of deposition of the material onto the surface of the workpiece.

64. The apparatus of claim 52, further comprising a driver motor operably connected to the polishing surface and the electrically conductive surface to produce orbital motion thereof.

65. A workpiece electrochemical deposition system comprising:

a workpiece load and unload station;

a clean system; and

a polishing system, wherein said polishing system includes at least one station configured for electrochemical deposition, said station comprising a polishing surface having electrical conductors embedded therein.

66. The workpiece polishing system of claim 65, wherein said polishing system further comprises a polishing station configured to perform chemical mechanical polishing of a surface of the workpiece.

67. The workpiece polishing system of claim 65, further comprising a spin rinse dryer.

68. The workpiece polishing system of claim 65, wherein said polishing system further comprises a buff station.

69. The workpiece polishing system of claim 65, further comprising a least one robot configured to transport the workpiece from said load and unload station to said polishing system.

70. The workpiece polishing system of claim 65, further comprising a least one robot configured to transport the workpiece from said polishing system to said clean system.

71. The workpiece polishing system of claim 65, wherein said clean system includes a brush clean station.

72. The workpiece polishing system of claim 65, wherein said clean system includes a robot configured to transport a workpiece from a clean station to a spin rinse dryer.

73. The workpiece polishing system of claim 65, further comprising a metrology station.

74. A workpiece electrochemical deposition system comprising:

an electrochemical polishing station including a polishing surface; and

a plurality of workpiece carrier apparatus coupled to a central hub,

wherein at least one of said plurality of workpiece carrier apparatus is configured to urge a workpiece against the polishing surface during a material deposition process.

75. An apparatus for electrochemically depositing a film onto a surface of a workpiece, the apparatus comprising:

a polishing surface atop a rigid platen;

a driver motor operably connected to the rigid platen to produce orbital motion thereof;

an electrically conductive surface disposed proximate to the polishing surface and the rigid platen;

a plurality of conducting elements disposed at least partially in the polishing surface;

an electrolyte solution in contact with the polishing surface and the workpiece;

a workpiece carrier configured to press the workpiece against the polishing surface; and

a power source connected to the plurality of contact elements and the electrically conductive surface and configured to apply an electric potential difference between the workpiece and the electrically conductive surface to thereby deposit a film onto the surface of the workpiece.

76. An apparatus for electrochemically depositing a material onto a surface of a workpiece, the apparatus comprising:

a polishing pad;

a conducting surface disposed proximate the polishing pad; and

a plurality of contact elements disposed within said polishing pad, said contact elements configured to contact the surface of the workpiece when the workpiece is pressed against the polishing pad, said contact elements further configured for electrical communication with a power source for applying an electric potential between the surface of the workpiece and the conducting surface.

77. The apparatus of claim 76, wherein said plurality of contact elements is formed of at least one of conductively-enhanced polymer material, ceramic material and inorganic fibers.

78. A method of depositing a material onto a surface of a workpiece, the method comprising:

providing a polishing pad;

providing a conductive surface disposed proximate the polishing pad;

providing a plurality of contact elements disposed within said polishing pad;

pressing the workpiece against said polishing pad while causing relative motion between the workpiece and the polishing pad;

causing the surface of the workpiece to contact said plurality of contact elements during said pressing, and

applying an electric potential difference between the plurality of contact elements and the conductive surface.

79. The method of claim 78, further comprising supplying an electrolytic solution to a polishing surface of said polishing pad.