Surface wave plasma processing system and method of using

• US 20060071607A1
• Filed: 09/30/2004
• Published: 04/06/2006
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Chen, Lee, Matsumoto, Naoki, Tian, Caiz Hong
• Granted Patent: US 7,138,767 B2
• Time in Patent Office: Days
• US Class Current: 315/111.10
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/3222 Antennas

Abstract

A SWP source includes an electromagnetic (EM) wave launcher configured to couple EM energy in a desired EM wave mode to a plasma by generating a surface wave on a plasma surface of the EM wave launcher adjacent the plasma. A power coupling system is coupled to the EM wave launcher and configured to provide the EM energy to the EM wave launcher for forming the plasma. A cover plate coupled to the plasma surface of the EM wave launcher protects the EM wave launcher from the plasma.

Claims

1. A surface wave plasma (SWP) source comprising:

an electromagnetic (EM) wave launcher configured to couple EM energy in a desired EM wave mode to a plasma by generating a surface wave on a plasma surface of said EM wave launcher adjacent said plasma;

a power coupling system coupled to said EM wave launcher and configured to provide said EM energy to said EM wave launcher for forming said plasma; and

a cover plate coupled to said plasma surface of said EM wave launcher, and configured to protect said EM wave launcher from said plasma.

2. The SWP source of claim 1, wherein said EM wave launcher is configured to couple said desired EM wave mode as a TM₀₁ mode.

3. The SWP source of claim 1, wherein said cover plate is configured to be replaceable.

4. The SWP source of claim 1, wherein said cover plate comprises a thin sheet of material less than or equal to 5 mm in thickness.

5. The SWP source of claim 1, wherein a thickness of said cover plate is electromagnetically insignificant.

6. The SWP source of claim 1, wherein a thickness of said cover plate ranges from approximately 1 mm to 5 mm.

7. The SWP source of claim 1, wherein a thickness of said cover plate ranges from approximately 1 mm to 3 mm.

8. The SWP source of claim 1, wherein said cover plate comprises SiO₂.

9. The SWP source of claim 1, wherein said power coupling system comprises a radio frequency (RF) power coupling system.

10. The SWP source of claim 1, wherein said power coupling system comprises a microwave power coupling system.

11. The SWP source of claim 10, wherein said microwave power coupling system comprises:

a microwave source configured to produce microwave energy at 2.45 GHz;

a waveguide coupled to an outlet of said microwave source;

an isolator coupled to said waveguide and configured to prevent propagation of microwave energy back to said microwave source; and

a coaxial converter coupled to said isolator and configured to couple said microwave energy to a coaxial feed, wherein said coaxial feed is further coupled to said EM wave launcher.

12. The SWP source of claim 10, wherein:

said power coupling system comprises a coaxial feed for coupling EM energy to said EM wave launcher,

said EM launcher comprises a slot antenna with one end coupled to an inner conductor of said coaxial feed and another end coupled to an outer conductor of said coaxial feed, and

said slot antenna includes one or more slots configured to couple said EM energy from a first region above said slot antenna between said inner conductor and said outer conductor to a second region below said slot antenna.

13. The plasma processing system of claim 12, wherein said EM wave launcher further comprises:

a slow wave plate positioned in said first region and configured to reduce the effective wavelength of said EM energy relative to the wavelength in free space; and

a resonator plate positioned in said second region and having a lower surface of said resonator plate including said plasma surface of the EM wave launcher.

14. The SWP source of claim 13, wherein said slow wave plate and said resonator plate comprise the same material composition.

15. The SWP source of claim 13, wherein said slow wave plate and said resonator plate comprise different material compositions.

16. The SWP source of claim 14, wherein said slow wave plate and said resonator plate consist essentially of quartz.

17. The SWP source of claim 16, wherein said resonator plate comprises at least one concentric groove configured to improve spatial uniformity of a plasma.

18. The SWP source of claim 13, wherein said resonator plate comprises a high dielectric constant (high-k) material, said high dielectric constant material having a dielectric constant greater than a value of 4.

19. The SWP source of claim 18, wherein said resonator plate comprises one or more of intrinsic crystal silicon, alumina, and sapphire.

20. The SWP source of claim 13, wherein said cover plate is coupled to said lower surface of said resonator plate.

21. The SWP source of claim 20, wherein at least one of said resonator plate and said cover plate is polished in order to provide improved electrical contact at an interface of the cover plate and resonator plate.

22. The SWP source of claim 20, further comprising a thin film interposed between said resonator plate and said cover plate in order to provide improved electrical contact.

23. The SWP source of claim 22, wherein said thin film comprises at least one of a thermal SiO2 film and a deposited SiO2 thin film.

24. The SWP source of claim 1, further comprising a mode scrambler interposed between said plasma surface of the EM wave launcher and said cover plate, said mode scrambler configured to improve coupling between said EM wave launcher and said plasma.

25. A surface wave plasma (SWP) source comprising:

an electromagnetic (EM) wave launcher configured to couple EM energy in a desired EM wave mode to a plasma by generating a surface wave on a plasma surface of said EM wave launcher adjacent said plasma;

a power coupling system coupled to said EM wave launcher and configured to provide said EM energy to said EM wave launcher for forming said plasma; and

means, coupled to said plasma surface of said EM wave launcher, for protecting said EM wave launcher from said plasma.

26. The SWP source of claim 25, further comprising means, interposed between said plasma surface of the EM wave launcher, for improving coupling between said EM wave launcher and said plasma.