Claims
- 1. Apparatus for generating a plasma, said apparatus comprising:
a plasma chamber containing a gas, said chamber enclosing a cylindrical region which has a longitudinal center axis and having two axial ends that are spaced apart along the axis; and a coil system for converting a field-generating current into a RF magnetic field in the chamber to interact with gas in order to sustain a plasma within the cylindrical region, being composed of a plurality of annular zones concentric with the center axis and disposed at respectively different distances from the center axis, wherein:
said coil system comprises a plurality of individual coils each positioned and dimensioned to produce a RF magnetic field which predominantly influences a respective annular zone of the cylindrical region; and said chamber is shaped to have a continuous surface that extends past the end of each of said individual coils.
- 2. The apparatus of claim 1 wherein each of said individual coils has a respectively different mean diameter.
- 3. The apparatus of claim 2 wherein each of said individual coils is a multiturn coil.
- 4. The apparatus of claim 3 wherein at least one of said individual coils is a flat coil having turns which lie on a common plane that is perpendicular to the center axis.
- 5. The apparatus of claim 3 wherein at least one of said coils is a conical coil having turns which lie on a plane that defines a conical surface.
- 6. The apparatus of claim 3 wherein at least one of said individual coils is a cylindrical coil having turns which lie on a plane that defines a cylindrical surface.
- 7. The apparatus of claim 3 wherein each of said coils is a helical resonant coil.
- 8. The apparatus of claim 7 wherein each of said helical resonant coils has a first end which is grounded and a second end which is open circuited.
- 9. The apparatus of claim 7 wherein all of said coils are tuned to be resonant at the same frequency.
- 10. The apparatus of claim 7 wherein all of said coils are tuned to be resonant at respectively different frequencies.
- 11. The apparatus of claim 2 wherein said coils are spaced apart from one another in a direction along the center axis.
- 12. The apparatus of claim 2 wherein each of said coils is a single turn coil.
- 13. The apparatus of claim 12 further comprising a plurality of capacitors each connected between one end of a respective coil and a ground point.
- 14. The apparatus of claim 13 wherein each of said capacitors is a variable capacitor.
- 15. The apparatus of claim 12 wherein said coils are spaced apart from one another in a direction along the center axis.
- 16. The apparatus of claim 1 in combination with means for applying an individually controlled field generation voltage to each of said coils.
- 17. The apparatus of claim 1, further comprising means connected to said coils for applying an individually controlled field generating voltage to each of said coils.
- 18. The apparatus of claim 1, further comprising means for introducing the gas into said chamber, said means being located for introducing all of the gas at a location that is enclosed by all of said individual coils.
- 19. Apparatus for generating a plasma, said apparatus comprising:
a plasma chamber containing a gas, said chamber enclosing a cylindrical region which has a longitudinal center axis and having two axial ends that are spaced apart along the axis; and a coil system for converting a field-generating current into a RF magnetic field in the chamber to interact with gas in order to sustain a plasma within the cylindrical region, being composed of a plurality of annular zones concentric with the center axis and disposed at respectively different distances from the center axis, wherein:
said coil system comprises a plurality of individual coils each positioned and dimensioned to produce a RF magnetic field which predominantly influences a respective annular zone of the cylindrical region; and said apparatus further comprises means for introducing the gas into said chamber, said means being located for introducing all of the gas at a location that is enclosed by all of said individual coils.
Parent Case Info
[0001] This application is a continuation application of International Application No. PCT/US01/06239, filed Feb. 28, 2001 and derives the benefit of U.S. Provisional application No. 60/186,279, filed Mar. 1, 2000, 2000, the contents of both are incorporated herein by reference.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60186279 |
Mar 2000 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/US01/06239 |
Feb 2001 |
US |
Child |
10229036 |
Aug 2002 |
US |