Hermetically-sealed inductively-coupled plasma source structure and method of use

• US 6,209,480 B1
• Filed: 07/10/1996
• Issued: 04/03/2001
• Est. Priority Date: 07/10/1996
• Status: Expired due to Fees

• Current Assignee: CVC Products, Inc. (Veeco Instruments Incorporated)
• Original Assignee: CVC Products, Inc. (Veeco Instruments Incorporated)
• Inventors: Moslehi, Mehrdad M.
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): Zervigon, Rudy
• Application Number:
  US08/677,849
• Time in Patent Office: 1,728 Days
• Field of Search: 156/345 C, 118/723 I, 118/723 IR, 204/298.34
• US Class Current: 118/723.00I
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma

Abstract

A multi-zone high-density inductively-coupled plasma source includes a first individually controlled RF antenna segment for producing a plasma from a process gas. A second individually controlled coil segment is included in the ICP source for producing a plasma from a process gas. In various embodiments, more than two sets of individually controlled coil segments may be used. In one embodiment, a separate power supply may be used for each coil segment individually.

Another aspect of this invention is a hermetically-sealed inductively-coupled plasma source structure and method of fabrication which eliminates the possibility of process contamination, improves the source hardware reliability and functionality, and improves the vacuum integrity and ultimate base pressure of the plasma system.

Claims

1. A hermetically-sealed inductively-coupled plasma (ICP) source structure, comprising.

a dielectric housing an inductively-coupled source antenna integral to said dielectric housing;

a source support plate contacting said dielectric housing; and

a hermetically-sealed junction formed between said dielectric housing; and

said source support plate, wherein said hermetically sealed junction is formed by thermal bonding process and wherein said hermetically sealed junction is formed over entire area of said source plate.

2. The hermetically sealed ICP source structure of claim 1 wherein said thermal bonding process comprises an alloy with a melting point T ≦

600 °

C.

3. The hermetically-sealed ICP source structure of claim 1 wherein said hermetically-sealed junction is formed by a thermal brazing process.

4. The hermetically-sealed ICP source structure of claim 1 wherein said dielectric housing is made of a high thermal conductivity ceramic material.

5. The hermetically-sealed ICP source structure of claim 1 wherein said dielectric housing comprises aluminum nitride.

6. The hermetically-sealed ICP source structure of claim 1 wherein said dielectric housing comprises a high-thermal-conductivity vacuum-compatible polymer-based material.

7. The hermetically-sealed ICP source structure of claim 1 wherein said dielectric housing comprises at least one dielectric plate.

8. The hermetically-sealed ICP source structure of claim 7 wherein said dielectric housing comprises a lower dielectric plate and an upper dielectric plate.

9. The hermetically-sealed ICP source structure of claim 8 wherein said upper dielectric plate coupled to said lower dielectric plates such that said inductively-coupled source antenna is held between the lower dielectric plate and the upper dielectric plate.

10. The hermetically-sealed ICP source structure of claim 8 wherein said lower dielectric plate couples to said upper dielectric plates using at least one hermetically-sealed contact junction.

11. The hermetically-sealed ICP source structure of claim 10 wherein said at least one hermetically sealed contact junction between said lower dielectric plate and said upper dielectric plate is formed using a thermal bonding process to bond said lower dielectric plate to said upper dielectric plate.

12. The hermetically-sealed ICP source structure of claim 11 wherein the thermal bonding process comprises an alloy with a melting point ≦

600°

C.

13. The hermetically-sealed ICP source structure of claim 12 wherein the low melting point bonding alloy comprises indium.

14. The hermetically-sealed ICP source structure of claim 10 wherein said at least one hermetically-sealed contact junction between said lower dielectric plate and said upper dielectric plate is formed using a thermal brazing process.

15. The hermetically-sealed ICP source structure of claim 10 wherein said upper dielectric plate further comprises a plurality of feedthroughs operable to provide electrical connections to said source antenna.

16. The hermetically-sealed ICP source structure of claim 15 wherein said electrical connections are hermetically sealed to said the plurality of upper dielectric plate feedthroughs.

17. The hermetically-sealed ICP source structure of claim 16 wherein said hermetical sealing of said electrical connections comprises thermal bonding.

18. The hermetically-sealed ICP source structure of claim 15 wherein said upper dielectric plate further comprises at least one feedthrough operable to receive a process gas inlet tube.

19. The hermetically-sealed ICP source structure of claim 18 wherein each process gas inlet tube is hermetically sealed to said at least one feedthrough operable to receive a process gas inlet tube.

20. The hermetically-sealed ICP source structure of claim 18 wherein said hermetical sealing of said feedthrough to said inlet process gas tube comprises thermal bonding.

21. The hermetically-sealed ICP source structure of claim 11 wherein said upper dielectric plate further comprises a plurality of embedded gas dispersion channels, said dispersion channels operable to direct process gas flow.

22. The hermetically-sealed ICP source structure of claim 1 wherein said source support plate comprises a stainless steel support plate.

23. The hermetically-sealed ICP source structure of claim 1 wherein said source support plate comprises an aluminum support plate.

24. The hermetically-sealed ICP source structure of claim 1 wherein said source support plate couples to a plasma process chamber to provides a vacuum seal interface to the plasma process chamber.

25. The hermetically-sealed ICP source structure of claim 1 wherein said ICP source is a single-zone ICP source.

26. The hermetically-sealed ICP source structure of claim 1 wherein said ICP source is a multi-zone ICP source.

27. The hermetically-sealed ICP source structure of claim 1 further comprising coolant channels formed within said support plate, said coolant channels operable to flow a coolant to cool said ICP source.

28. The hermetically-sealed ICP source structure of claim 1 wherein said support plate further comprises feedthroughs for electrical connections to said antenna and further to allow process gas flow into a plasma process chamber.

29. The hermetically-sealed ICP source structure of claim 1 wherein said ICP source is a substantially planar assembly comprising a substantially planar dielectric housing, a substantially planar source support plate, and a substantially planar hermetically sealed junction.

30. The hermetically-sealed ICP source structure of claim 9 wherein said source antenna is formed as a monolithic patterned layer by depositing an electrically conducting metallic layer onto a surface of the lower dielectric plate having trenches formed in the surface of the lower dielectric plate.

31. The hermetically-sealed ICP source structure of claim 9 wherein said source antenna is formed as a monolithic patterned layer by depositing an electrically conducting metallic layer onto a surface of the upper dielectric plate having trenches formed in the surface of the upper dielectric plate.

32. The hermetically-sealed ICP source structure of claim 1 wherein said source antenna is formed as a separate component and placed in designated trenches between said upper dielectric plate and said lower dielectric plate.

34. The hermetically-sealed ICP source structure of claim 1 wherein said hermetically-sealed junction is formed by fusing the said dielectric housing and said support plate.

35. The hermetically-sealed ICP source structure of claim 34 wherein fusing said dielectric housing and said support plate comprises brazing.

36. The hermetically-sealed ICP source structure of claim 1 wherein said hermetically-sealed junction is formed by an epoxy bond between said dielectric housing and said support plate.

37. The hermetically-sealed ICP source structure of claim 10 wherein said at least one hermetically-sealed contact junction between said lower dielectric plate and said upper dielectric plate is formed by fusing said lower dielectric plate to said upper dielectric plate.

38. The hermetically-sealed ICP source structure of claim 37 wherein fusing comprises brazing.

39. The hermetically-sealed ICP source structure of claim 38 wherein brazing comprises using indium.

40. The hermetically-sealed ICP source structure of claim 15 wherein said electrical connections are fused to said hermetically-sealed to said the plurality of upper dielectric feedthroughs.

41. The hermetically-sealed ICP source structure of claims 1 wherein said hermetically-sealed junction is formed using an alloy with a melting point <

400°

C.

42. The hermetically-sealed ICP source structure of claim 1 wherein said hermetically-sealed junction is formed using an alloy with a melting point <

300°

C.

43. The hermetically-sealed ICP source structure of claim 1, wherein the hermetically-sealed junction comprises a continuous interface along all the points on surface of the dielectric housing which contact a surface of the source support plate.

44. The hermetically-sealed ICP source structure of claim 1, wherein the source support plate is operable to be sealed to a process chamber using a hermetic seal.

45. The hermetically-sealed ICP source structure of claim 44, wherein the hermetic seal of between the process chamber to the hermetically-sealed ICP source structure is a metal-to-metal seal.

46. The hermetically-sealed ICP source structure of claim 1, wherein heat generated during plasma generation by the inductively-coupled source antenna is removed by direct heat transfer mechanism having a thermal conductivity greater than that of epoxy.

47. The hermetically-sealed ICP source structure of claim 46, wherein the direct heat transfer mechanism comprises a ceramic lower and upper dielectric plate with a thermal conductivity greater than that of epoxy.

33. A hermetically-sealed multi-zone inductively-coupled plasma source, for producing a plasma medium comprising:

a first antenna structure for substantially inductive coupling of radio-frequency electrical power to said plasma medium;

at least one additional antenna structure for inductive coupling of additional radio-frequency electrical power to said plasma medium, wherein said first antenna structure and said at least one additional antenna structure are operated together for providing a substantially uniform plasma process on at least one substrate placed in a low-pressure plasma processing equipment;

a plurality of radio-frequency power supplies operable to supply power to said antenna structures;

a controller operable to control the plurality of radio frequency power supplies in order to provide a substantially uniform plasma process;

a dielectric housing, integrally including the inductively-coupled source antenna, said dielectric housing further comprising;

a lower dielectric plate; and

an upper dielectric plate, wherein said upper dielectric plate couples to said lower dielectric plates such that said inductively-coupled source antenna is held between the lower dielectric plate and the upper dielectric plate, and further wherein said lower dielectric plate couples to said upper dielectric plates using at least one hermetically-sealed contact junction;

a source support plate contacting said dielectric housing; and

a hermetically-sealed junction formed between said dielectric housing and said source support plate.