Method and apparatus for use of hydrogen and silanes in plasma

• US 6,448,186 B1
• Filed: 10/06/2000
• Issued: 09/10/2002
• Est. Priority Date: 10/06/2000
• Status: Expired due to Term

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Ravi, Tirunelveli S., Krebs, Jerrod Paul, Swope, Richard S., Olson, Darin S.
• Primary Examiner(s): Everhart, Caridad
• Application Number:
  US09/684,571
• Time in Patent Office: 704 Days
• Field of Search: 438/758, 438/725, 438/745, 438/542, 427/255.6, 427/492, 427/493, 427/126.2, 427/96, 427/377, 427/387, 257/759
• US Class Current: 438/758
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: C23C 16/505 using radio frequency discharges
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC

Abstract

A hydrogen-containing chemical species is included in the reactant gas mixture in a plasma-enhanced CVD process for forming a carbon-containing dielectric film. The CVD reactant gas mixture contains silicon, oxygen, hydrogen and carbon atoms for forming a novel carbon-containing silicon oxide film in which both Si—C and Si—H bonds are present. Because dielectric material deposited in accordance with the invention has a significant number of Si—H bonds, which are more robust than Si—C bonds, it is more resistant to undesired etching and other physical changes during fabrication than dielectric material formed by conventional methods. A method in accordance with the invention allows a faster deposition rate. A dielectric film formed in accordance with the invention has enhanced uniformity characteristics and a dielectric constant less than 3.

Claims

1. A plasma-assisted method for forming a dielectric film having Si—

O, Si—

C and Si—

H bonds on a substrate, comprising steps of;

flowing a gaseous carbon-containing organosilicon precursor compound having a Si—

C bond into a reaction chamber;

flowing a gaseous hydrogen-containing precursor compound into said reaction chamber, said hydrogen-containing precursor compound comprising a Si—

H bond and said hydrogen-containing precursor compound not comprising a carbon atom;

flowing a gaseous oxidizer that is not H₂O₂ into said reaction chamber;

flowing a plasma-forming gas into said reaction chamber; and

forming a plasma with said plasma-forming gas.

2. A method as in claim 1 wherein said gaseous oxidizer is nitrous oxide, having. stoichiometric formula N₂O.

3. A method as in claim 1 wherein said hydrogen-containing compound is silane, having a stoichiometric formula SiH₄.

4. A method as in claim 1 wherein said carbon-containing organosilicon precursor compound is an alkyl silane.

5. A method as in claim 4 wherein said alkyl silane is selected from the group consisting of trimethyl silane and tetramethyl silane.

6. A method as in claim 1 wherein said reaction chamber comprises SiH₄ and an alkyl silane.

7. A method as in claim 1 wherein forming a plasma comprises applying a high-frequency radio-frequency field to said plasma-forming gas.

8. A method as in claim 7 wherein said radio-frequency field as a frequency of about 13.56 MHz.

9. A method as in claim 7 wherein applying a high-frequency radio-frequency field to said plasma-forming gas comprises applying RF power in a range of about from 100 to 2500 watts.

10. A method as in claim 1 further comprising steps of maintaining pressure in said reaction chamber in a range of about from 1 to 5 Torr.

11. A method as in claim 1 further comprising steps of maintaining a temperature of said reaction chamber in a range of about from 200°

to 400°

C.

12. A method as in claim 11 wherein said reaction chamber is included in a PECVD apparatus.

13. A method as in claim 1 wherein forming a plasma comprises applying a low-frequency radio-frequency field to said plasma-forming gas and applying a high-frequency radio-frequency bias to said substrate.

14. A method as in claim 1 wherein said reaction chamber is included in a HDP-CVD apparatus.

15. A plasma-assisted method for forming a dielectric film having Si—

O, Si—

C and Si—

H bonds on a substrate, comprising steps of;

flowing a gaseous oxidizer-free precursor stream into a reaction chamber, said oxidizer-free gaseous precursor stream including a non-oxidizing precursor compound comprising an Si—

C bond and a non-oxidizing precursor compound comprising an Si—

O bond;

flowing a gaseous oxidizer-free stream comprising a hydrogenating gas into said reaction chamber;

flowing an inert plasma-forming gas into said reaction chamber; and

forming a plasma with said plasma-forming gas,

wherein said reaction chamber substantially free of reactive oxygen.

16. A method as in claim 15 wherein said hydrogenating gas is hydrogen-gas, H₂.

17. A method as in claim 15 wherein said precursor compound comprising a Si—

C bond contains an alkyl group.

18. A method as in claim 15 wherein a precursor compound comprises a Si—

C bond and a Si—

O bond.

19. A method as in claim 18 wherein said precursor compound is octamethylcyclotetrasiloxane, corresponding to the stoichiometric formula (SiO(CH₃)₂)₄.

20. A method as in claim 15 wherein said reaction chamber comprises an inert gas.

21. A method as in claim 15 wherein forming a plasma comprises applying a low-frequency radio-frequency field to said plasma-forming gas.

22. A method as in claim 21 wherein said radio-frequency field has a frequency in a range of about from 200 kHz to 1000 kHz.

23. A method as in claim 21 wherein applying a low-frequency radio-frequency field to said plasma-forming gas comprises applying RF power in a range of about from 200 to 1000 watts.

24. A method as in claim 21 further comprising steps of applying a high-frequency radio-frequency bias to said substrate.

25. A method as in claim 24 wherein said applying a high-frequency radio-frequency bias comprises applying/a bias voltage having a frequency in a range of about from 8 MHz to 20 MHz.

26. A method as in claim 25 wherein said applying a bias voltage comprises apple, power in a range of about from 500 watts to 1500 watts.

27. A method as in claim 24 wherein said applying a high-frequency bias comprises applying a high-frequency bias pulse-wise to said substrate.

28. A method as in claim 24 herein said applying a high-frequency bias comprises tailoring a magnitude of said high-frequency bias.

29. A method as in claim 28 wherein said tailoring a magnitude of said high-frequency bias comprises decreasing said magnitude from about 5 kW to about 0 kW.

30. A method as in claim 15 further comprising steps of maintaining pressure in said reaction chamber in a range of about from 0.1 mTorr to 100 mTorr.

31. A method as in claim 30 further comprising steps of maintaining pressure in said reaction chamber in a range of about from 5 mTorr to 15 mTorr.

34. A method as in claim 15 wherein said reaction chamber is included in a HDP-CVD apparatus.

35. A method as in claim 15 wherein forming a plasma comprises applying a high-frequency radio-frequency field to said plasma-forming gas.

36. A method as in claim 15 wherein said reaction chamber is included in a PECVD apparatus.

32. A method as in 15 claim further comprising steps of maintaining a temperature of said reaction chamber in a range of about from 0 to 200°

C.

33. A method as in claim 32 further comprising steps of maintaining a temperature of said reaction chamber about 50°

C.

37. A dielectric film, having Si—

O, Si—

C and Si—

H bonds, fabricated by;

flowing a gaseous carbon-containing organosilicon precursor compound having a Si—

C bond into a reaction chamber;

flowing a gaseous hydrogen-containing precursor compound into said reaction chamber, said hydrogen-containing precursor compound comprising a Si—

H bond and said hydrogen-containing precursor compound not comprising a carbon atom;

flowing a gaseous oxidizer that is not H₂O₂ into said reaction chamber;

flowing a plasma-forming gas into said reaction chamber; and

forming a plasma with said plasma-forming gas.

38. A method as in claim 37 wherein said gaseous oxidizer is nitrous oxide, having a stoichiometric formula N₂O.

39. A dielectric film as in claim 37 wherein said hydrogen-containing compound comprises silane, having a stoichiometric formula SiH₄.

40. A dielectric film as in claim 37 wherein said carbon-containing organosilicon precursor compound is an alkyl silane.

41. A dielectric film as in claim 40 wherein said alkyl silane is selected from the grow consisting of trimethyl silane and tetramethyl silane.

42. A dielectric film as in claim 37 wherein said reaction chamber comprises SiH₄ and an alkyl silane.

43. A dielectric film as in claim 37 wherein forming a plasma comprises applying f high-frequency radio-frequency field to said plasma-forming gas.

44. A dielectric film as in claim 43 wherein said radio-frequency field as a frequency of about 13.56 MHz.

45. A dielectric film as in claim 43 wherein applying a high-frequency radio-frequency field to said plasma-forming gas comprises applying RF power in a range of about from 100 to 2500 watts.

46. A dielectric film as in claim 37 further comprising steps of maintaining pressure in said reaction chamber in a range of about from 1 to 5 Torr.

47. A dielectric film as in claim 37 further comprising steps of maintaining a temperature of said reaction chamber in a range of about from 200°

to 400°

C.

48. A dielectric film as in claim 37 wherein said reaction chamber is included in a PECVD apparatus.

49. A method as in claim 37 wherein forming a plasma comprises applying a low-frequency radio-frequency field to, said plasma-forming gas and applying a high-frequency radio-frequency bias to said substrate.

50. A method as in claim 37 wherein said reaction chamber is included in a HDP-CVD apparatus.

51. A dielectric film, having Si—

O, Si—

C and Si—

H bonds, fabricated by;

flowing a gaseous oxidizer-free precursor stream into a reaction chamber, said oxidizer-free gaseous precursor stream including a non-oxidizing precursor compound comprising an Si—

C bond and a non-oxidizing precursor compound comprising an Si—

O bond;

flowing a gaseous oxidizer-free stream comprising a hydrogenating gas into said reaction chamber;

flowing an inert plasma-forming gas into said reaction chamber; and

forming a plasma with said plasma-forming gas,

wherein said reaction chamber is substantially free of reactive oxygen.

52. A dielectric film as in claim 51 wherein said hydrogenating gas comprises hydrogen-gas, H₂.

53. A dielectric film as in claim 51 wherein said precursor compound comprising a Si—

C bond contains an alkyl group.

54. A dielectric film as in claim 51 wherein a precursor compound comprises a Si—

C bond and a Si—

O bond.

55. A dielectric film as in claim 51 wherein said gaseous precursor stream comprises octamethylcyclotetrasiloxane, corresponding to the stoichiometric formula (SiO(CH₃)₂)₄.

56. A dielectric film as in claim 51 wherein said reaction chamber comprises an inert gas.

57. A dielectric film as in claim 51 wherein forming a plasma comprises applying a low-frequency radio-frequency field to said plasma-forming gas.

58. A dielectric film as in claim 57 wherein said radio-frequency field has a frequency in a range of about from 200 kHz to 4000 kHz.

59. A dielectric film as in claim 57 wherein applying a low-frequency radio-frequency field to said plasma-forming gas comprises applying RF power in a range of about from 200 to 1000 watts.

60. A dielectric film as in claim 51 further comprising steps of applying a high-frequency radio-frequency bias to a substrate.

61. A dielectric film as in claim 60 wherein said applying a high-frequency radio-frequency bias comprises applying a bias voltage having a frequency in a range of about from 8 MHz to 20 MHz.

62. A dielectric film as in claim 61 wherein said applying a bias voltage comprises applying power in a range of about from 500 watts to 1500 watts.

63. A dielectric film as in claim 60 wherein said applying a high-frequency bias comprises applying a high-frequency bias pulse-wise to said substrate.

64. A dielectric film as in claim 60 wherein said applying a high-frequency bias comprises tailoring a magnitude of said high-frequency bias.

65. A dielectric film as in claim 64 wherein said tailoring a magnitude of said high-frequency bias comprises decreasing said magnitude from about 5 kW to about 0 kW.

66. A dielectric film as in claim 51 further comprising steps of maintaining pressure in said reaction chamber in a range of about from 0.1 mTorr to 100 mTorr.

67. A dielectric film as in claim 66 further comprising steps of maintaining pressure in said reaction chamber in a range of about from 5 mTorr to 15 mTorr.

68. A dielectric film as in claim 51 further comprising steps of maintaining a temperature of said reaction chamber in a range about from 0°

to 200°

C.

69. A dielectric film as in claim 68 further comprising steps of maintaining a temperature of said reaction chamber at about 50°

C.

70. A dielectric film as in claim 51 wherein said reaction chamber is includes in a HDP-CVD apparatus.

71. A method as in claim 51 wherein forming a plasma comprises applying a high-frequency radio-frequency field to said plasma-forming gas.

72. A method as in claim 51 wherein said reaction chamber is included in a apparatus.