Generation of Uniformly-Distributed Plasma

US 20040222745A1
Filed: 05/06/2003
Published: 11/11/2004
Est. Priority Date: 05/06/2003
Status: Active Grant

First Claim

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1. A plasma generator comprising:

a) a cathode assembly that is positioned adjacent to an anode and forming a gap there between;

b) a gas source that supplies a volume of feed gas to the gap between the cathode assembly and the anode; and

c) a power supply that generates an electric field across the gap between the cathode assembly and the anode, the electric field ionizing the volume of feed gas that is supplied to the gap, thereby creating a plasma in the gap.

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Abstract

Methods and apparatus for generating uniformly-distributed plasma are described. A plasma generator according to the invention includes a cathode assembly that is positioned adjacent to an anode and forming a gap there between. A gas source supplies a volume of feed gas and/or a volume of excited atoms to the gap between the cathode assembly and the anode. A power supply generates an electric field across the gap between the cathode assembly and the anode. The electric field ionizes the volume of feed gas and/or the volume of excited atoms that is supplied to the gap, thereby creating a plasma in the gap.

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53 Claims

1. A plasma generator comprising:
- a) a cathode assembly that is positioned adjacent to an anode and forming a gap there between;
  
  b) a gas source that supplies a volume of feed gas to the gap between the cathode assembly and the anode; and
  
  c) a power supply that generates an electric field across the gap between the cathode assembly and the anode, the electric field ionizing the volume of feed gas that is supplied to the gap, thereby creating a plasma in the gap.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- - 2. The plasma generator of claim 1 wherein the gas source comprises an excited atom source that generates a volume of excited atoms from a volume of feed gas, the excited atom source supplying the volume of excited atoms to the gap.
  - 3. The plasma generator of claim 1 wherein the cathode assembly comprises a hollow cathode comprising an inner surface that substantially surrounds the anode.
  - 4. The plasma generator of claim 3 wherein the inner surface comprises a cylindrical wall.
  - 5. The plasma generator of claim 1 wherein the cathode assembly comprises a target.
  - 6. The plasma generator of claim 1 further comprising a gas flow controller that controls the volume of feed gas that is injected in the gap.
  - 7. The plasma generator of claim 1 wherein the plasma created in the gap diffuses proximate to a surface of the cathode assembly.
  - 8. The plasma generator of claim 7 wherein the plasma is substantially uniformly-distributed proximate to the surface of the cathode assembly.
  - 9. The plasma generator of claim 7 wherein at least one of a width of the gap and a flow rate of the volume of feed gas that is supplied to the gap is chosen to increase a density of the plasma proximate to the surface of the cathode assembly.
  - 10. The plasma generator of claim 7 wherein at least one of a width of the gap and a flow rate of the volume of feed gas that is supplied to the gap is chosen to increase uniformity of the plasma proximate to the surface of the cathode assembly.
  - 11. The plasma generator of claim 7 wherein a pressure in the gap is higher than a pressure proximate to the surface of the cathode assembly.
  - 12. The plasma generator of claim 1 wherein the power supply is chosen from the group comprising a pulsed DC power supply, a RF power supply, an AC power supply, and a DC power supply.
  - 13. The plasma generator of claim 1 wherein the power supply generates a constant power.
  - 14. The plasma generator of claim 1 wherein the power supply generates a constant voltage.
  - 15. The plasma generator of claim 1 wherein a width of the gap is in the range of about 0.3 cm to 10 cm.
  - 16. The plasma generator of claim 1 further comprising a magnet assembly that generates a magnet field that substantially traps electrons in the plasma.
  - 17. The plasma generator of claim 1 wherein a peak plasma density of the plasma is in the range of about 10⁷cm⁻
    - 3 to 10¹⁶cm^−
      
      3.

18. A plasma generator comprising:
- a) a cathode assembly that is positioned adjacent to an anode and forming a gap there between;
  
  b) an excited atom source that generates a volume of excited atoms from a volume of feed gas, the excited atom source supplying the volume of excited atoms to the gap between the cathode assembly and the anode; and
  
  c) a power supply that generates an electric field across the gap between the cathode assembly and the anode, the electric field ionizing the volume of excited atoms that is supplied to the gap, thereby creating a plasma in the gap.
- View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
- - 19. The plasma generator of claim 18 wherein at least a portion of the volume of excited atoms comprises metastable atoms.
  - 20. The plasma generator of claim 18 wherein the cathode assembly comprises a hollow cathode comprising an inner surface that substantially surrounds the anode.
  - 21. The plasma generator of claim 20 wherein the inner surface comprises a cylindrical wall.
  - 22. The plasma generator of claim 18 further comprising a gas flow controller that controls the volume of excited atoms supplied to the gap.
  - 23. The plasma generator of claim 18 wherein the plasma created in the gap diffuses proximate to a surface of the cathode assembly.
  - 24. The plasma generator of claim 23 wherein the plasma is substantially uniformly-distributed proximate to the surface of the cathode assembly.
  - 25. The plasma generator of claim 23 wherein at least one of a width of the gap and a flow rate of the volume of excited atoms that is supplied to the gap is chosen to increase a density of the plasma proximate to the surface of the cathode assembly.
  - 26. The plasma generator of claim 23 wherein at least one of a width of the gap and a flow rate of the volume of excited atoms that is supplied to the gap is chosen to increase uniformity of the plasma proximate to the surface of the cathode assembly.
  - 27. The plasma generator of claim 18 wherein a width of the gap is in the range of about 0.3 cm to 10 cm.
  - 28. The plasma generator of claim 18 further comprising a magnet assembly that generates a magnet field that substantially traps electrons in the plasma.

29. A method for generating a plasma, the method comprising:
- a) supplying a volume of feed gas to a gap between a cathode assembly and an anode; and
  
  b) applying an electric field across the gap, the electric field ionizing the volume of feed gas that is supplied to the gap, thereby creating a plasma in the gap.
- View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
- - 30. The method of claim 29 further comprising generating a volume of excited atoms from a volume of feed gas and supplying the volume of excited atoms to the gap.
  - 31. The method of claim 29 further comprising adjusting a flow rate of the volume of feed gas supplied to the gap so as to increase a density of the plasma.
  - 32. The method of claim 29 wherein the plasma created in the gap diffuses proximate to a surface of the cathode assembly.
  - 33. The method of claim 32 further comprising adjusting the flow rate of the volume of feed gas supplied to the gap so as to increase uniformity of the plasma proximate to the surface of the cathode assembly.
  - 34. The method of claim 32 further comprising selecting a width of the gap to increase a density of the plasma proximate to the surface of the cathode assembly.
  - 35. The method of claim 32 further comprising selecting a width of the gap to increase uniformity of the plasma proximate to the surface of the cathode assembly.
  - 36. The method of claim 29 further comprising supplying a second volume of feed gas to the gap, the second volume of feed gas displacing the plasma.
  - 37. The method of claim 29 wherein the applying the electric field across the gap comprises applying a quasi-static electric field across the gap.
  - 38. The method of claim 29 wherein the applying the electric field across the gap comprises applying a pulsed electric field across the gap.
  - 39. The method of claim 38 further comprising selecting characteristics of the pulsed electric field to increase an ionization rate of the plasma.
  - 40. The method of claim 38 wherein a rise time of the pulsed electric field is in the range of about 0.1 microsecond to 10 seconds.
  - 41. The method of claim 29 wherein the applying the electric field across the gap comprises applying the electric field at a constant power.
  - 42. The method of claim 29 wherein the applying the electric field across the gap comprises applying the electric field at a constant voltage.
  - 43. The method of claim 29 wherein a peak plasma density of the plasma is in the range of about 10⁷cm⁻
    - 3 to 10¹⁶cm^−
      
      3.
  - 44. The method of claim 29 further comprising generating a magnetic field proximate to the plasma, the magnetic field trapping electrons in the plasma, thereby increasing the density of the plasma.
  - 45. The method of claim 44 wherein the magnetic field generated proximate to the plasma in the gap and the electric field applied across the gap intersect in the gap.

46. A method for generating a plasma, the method comprising:
- a) generating a volume of excited atoms from a volume of feed gas;
  
  b) supplying the volume of excited atoms to a gap between a cathode assembly and an anode; and
  
  c) applying an electric field across the gap, the electric field ionizing the volume of excited atoms that is supplied to the gap, thereby creating a plasma in the gap.
- View Dependent Claims (47, 48, 49, 50, 51)
- - 47. The method of claim 46 wherein at least a portion of the volume of excited atoms comprises metastable atoms.
  - 48. The method of claim 46 wherein the plasma created in the gap diffuses proximate to a surface of the cathode assembly.
  - 49. The method of claim 48 further comprising adjusting a flow rate of the volume of excited atoms to increase a density of the plasma proximate to the surface of the cathode assembly.
  - 50. The method of claim 48 further comprising adjusting the flow rate of the volume of excited atoms to increase uniformity of the plasma proximate to the surface of the cathode assembly.
  - 51. The method of claim 46 further comprising supplying a second volume of feed gas to the gap, the second volume of feed gas displacing the plasma.

52. A plasma generator comprising:
- a) means for supplying a volume of feed gas to a gap between a cathode assembly and an anode; and
  
  b) means for applying an electric field across the gap, the electric field ionizing the volume of feed gas that is supplied to the gap, thereby creating a plasma in the gap.

53. A plasma generator comprising:
- a) means for generating a volume of excited atoms from a volume of feed gas;
  
  b) means for supplying the volume of excited atoms to a gap between a cathode assembly and an anode; and
  
  c) means for applying an electric field across the gap, the electric field ionizing the volume of excited atoms that is supplied to the gap, thereby creating a plasma in the gap.

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Current Assignee
ZOND Incorporated
Original Assignee
ZOND Incorporated
Inventors
Chistyakov, Roman

Granted Patent

US 6,903,511 B2
Time in Patent Office

Days
Field of Search
US Class Current

315/111.41
CPC Class Codes

C23C 14/34   Sputtering

C23C 14/35   by application of a magneti...

H01J 37/3244   Gas supply means

H01J 37/3405   Magnetron sputtering

Generation of Uniformly-Distributed Plasma

First Claim

1 Assignment

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Abstract

67 Citations

53 Claims

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Generation of Uniformly-Distributed Plasma

First Claim

1 Assignment

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0 Petitions

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Accused Products

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Abstract

67 Citations

53 Claims

Specification

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Solutions

Use Cases

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