Method of depositing low dielectric constant silicon carbide layers

• US 6,537,733 B2
• Filed: 02/23/2001
• Issued: 03/25/2003
• Est. Priority Date: 02/23/2001
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Campana, Francimar, Chapin, Michael, Venkataraman, Shankar, Nemani, Srinivas
• Primary Examiner(s): Meeks, Timothy
• Application Number:
  US09/793,818
• Publication Number:
  US 20020119250A1
• Time in Patent Office: 760 Days
• Field of Search: 430/313, 430/314, 430/316, 430/317, 438/700, 438/702, 438/717, 438/637, 438/783, 438/784, 438/786, 427/578, 427/577, 427/249.15, 427/255.29
• US Class Current: 430/313
• CPC Class Codes: C23C 16/36 Carbonitrides
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/0276 using an anti-reflective coating anti-reflective coating for lithography in general G03F7/09
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/314 Inorganic layers H01L21/3105, H01L21/32 take precedence
• CPC Class Codes: H01L 21/76808 involving intermediate temporary filling with material
• CPC Class Codes: H01L 21/76813 involving a partial via etch
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 2221/1031 Dual damascene by forming vias in the via-level dielectric prior to deposition of the trench-level dielectric

Abstract

A method of forming a silicon carbide layer for use in integrated circuits is provided. The silicon carbide layer is formed by reacting a gas mixture comprising a silicon source, a carbon source, and a nitrogen source in the presence of an electric field. The as-deposited silicon carbide layer incorporates nitrogen therein from the nitrogen source.

Claims

1. A method of thin film deposition, comprising:

positioning a substrate in a deposition chamber;

providing a gas mixture to the deposition chamber, wherein the gas mixture comprises a silicon source, a carbon source, and a nitrogen source;

reacting the gas mixture in the presence of an electric field to form a nitrogen-containing silicon carbide layer on the substrate; and

then

exposing the nitrogen-containing silicon carbide layer to a plasma by;

providing one or more inert gas to a process chamber having the substrate therein with the nitrogen-containing silicon carbide layer formed thereon; and

applying an electric field to the one or more inert gas to generate a plasma in the process chamber.

2. The method of claim 1 wherein the silicon source and the carbon source comprise an organosilane compound having the general formula Si_xC_yH_z, wherein x has a range of 1 to 2, y has a range of 1 to 6, and z has a range of 4 to 18.

3. The method of claim 2 wherein the organosilane compound is selected from the group consisting of methylsilane (SiCH₆), dimethylsilane (SiC₂H₈), trimethylsilane (SiC₃H₁₀), tetramethylsilane (SiC₄H₁₂), diethylsilane (SiC₄H₁₂), and combinations thereof.

4. The method of claim 1 wherein the silicon source and the carbon source are selected from the group consisting of silane (SiH₄), methane (CH₄), disilane (Si₂H₆), and combinations thereof.

5. The method of claim 1 wherein the nitrogen source is selected from the group consisting of ammonia (NH₃), nitrogen (N₂), and combinations thereof.

6. The method of claim 1 wherein the gas mixture further comprises an inert gas.

7. The method of claim 6 wherein the inert gas is selected from the group consisting of helium (He), argon (Ar), neon (Ne), and combinations thereof.

8. The method of claim 1 wherein the ratio of the silicon source to the nitrogen source in the gas mixture has a range of about 1:

1 to about 1;

100.

9. The method of claim 1 wherein the substrate is heated to a temperature in a range of about 150°

C. to about 450°

C.

10. The method of claim 1 wherein the deposition chamber is maintained at a pressure between about 1 torr to about 15 torr.

11. The method of claim 1 wherein either of the silicon source or the carbon source is provided to the deposition chamber at a flow rate in a range of about 10 sccm to about 4,000 sccm.

12. The method of claim 1 wherein the nitrogen source is provided to the deposition chamber at a flow rate in a range of about 50 sccm to about 10,000 sccm.

13. The method of claim 1 wherein the electric field is generated from one or more radio frequency (RF) powers.

14. The method of claim 13 wherein each of the one or more RF powers is within a range of about 1 watt/cm² to about 10 watts/cm².

15. The method of claim 1 wherein the nitrogen-containing silicon carbide layer has a dielectric constant less than about 5.5.

16. The method of claim 1 wherein the nitrogen-containing silicon carbide layer is an anti-reflective coating (ARC) at wavelengths less than about 250 nm.

17. The method of claim 1 wherein the nitrogen-containing silicon carbide layer has a leakage current less than about 10⁻

9 A/cm² at 2 MV/cm.

18. The method of claim 1 wherein the nitrogen-containing silicon carbide layer has a compressibility greater than about 5×

10⁸ dynes/cm².

19. The method of claim 1 wherein the one or more inert gas is selected from the group consisting of helium (He), argon (Ar), neon (Ne), and combinations thereof.

20. The method of claim 1 wherein the process chamber is maintained at a pressure in a range of about 5 torr to about 10 torr.

21. The method of claim 1 wherein the one or more inert gas is provided to the process chamber at a flow rate in a range of about 1,000 sccm to about 7,000 sccm.

22. The method of claim 1 wherein the electric field is a radio frequency (RF) power.

23. The method of claim 22 wherein the RF power is in a range of about 1 watt/cm² to about 10 watts/cm².

24. The method of claim 1, further comprising forming a silicon carbide cap layer on the nitrogen-containing silicon carbide layer.

25. A method of forming a device, comprising:

forming a nitrogen-containing silicon carbide layer on a substrate in a deposition chamber, wherein the nitrogen-containing silicon carbide layer is formed by reacting a gas mixture comprising a silicon source, a carbon source, and a nitrogen source in the presence of an electric field;

plasma treating the nitrogen-containing silicon carbide layer by;

providing one or more inert gas to a process chamber having the substrate therein with the nitrogen-containing silicon carbide layer formed thereon; and

applying an electric field to the one or more inert gas to generate a plasma in the process chamber; and

defining a pattern in at least one region of the nitrogen-containing silicon carbide layer.

26. The method of claim 25, further comprising transferring the pattern defined in the at least one region of the nitrogen-containing silicon carbide layer into the substrate using the nitrogen-containing silicon carbide layer as a mask.

27. The method of claim 26, further comprising removing the nitrogen-containing silicon carbide layer from the substrate.

28. The method of claim 27 wherein the nitrogen-containing silicon carbide layer is removed from the substrate using a fluorine-based compound.

29. The method of claim 28 wherein the fluorine-based compound is selected from the group consisting of carbon tetrafluoride (CF₄) and trifluoromethane (CF₃H).

30. The method of claim 25 wherein the substrate has one or more material layers formed thereon.

31. The method of claim 25, wherein definition of the pattern in the at least one region of the nitrogen-containing silicon carbide layer, comprises:

forming a layer of energy sensitive resist material on the nitrogen-containing silicon carbide layer;

introducing an image of the pattern into the layer of energy sensitive resist material by exposing the energy sensitive resist material to patterned radiation;

developing the image of the pattern introduced into the layer of energy sensitive resist material; and

transferring the pattern through the nitrogen-containing silicon carbide layer using the layer of energy sensitive resist material as a mask.

32. The method of claim 31, further comprising:

forming an intermediate layer on the nitrogen-containing silicon carbide layer prior to forming the layer of energy sensitive resist material thereon, introducing the image of the pattern to the intermediate layer, and developing the pattern;

transferring the image of the pattern developed in the layer of energy sensitive resist material through the intermediate layer using the layer energy sensitive resist material as a mask; and

transferring the pattern through the nitrogen-containing silicon carbide layer using the intermediate layer as a mask.

33. The method of claim 32 wherein the intermediate layer is an oxide.

34. The method of claim 33 wherein the oxide is selected from the group consisting of silicon dioxide and fluorosilicate glass (FSG).

35. The method of claim 25 wherein the nitrogen-containing silicon carbide layer is an anti-reflective coating (ARC) at wavelengths less than about 250 nm (nanometers).

36. The method of claim 25 wherein the nitrogen-containing silicon carbide layer has an absorption coefficient (κ

) within a range of about 0.1 to about 0.6 at wavelengths less than about 250 nm.

37. The method of claim 36 wherein the absorption coefficient (κ

) varies within a range of about 0.1 to about 0.6 across the thickness of the nitrogen-containing silicon carbide layer.

38. The method of claim 35 wherein the nitrogen-containing silicon carbide layer has an index of refraction within a range of about 1.6 to about 2.2.

39. The method of claim 25 wherein the silicon source and the carbon source comprise an organosilane compound having the general formula Si_xC_yH_z, wherein x has a range of 1 to 2, y has a range of 1 to 6, and z has a range of 4 to 18.

40. The method of claim 39 wherein the organosilane compound is selected from the group consisting of methylsilane (SiCH₆), dimethylsilane (SiC₂H₈), trimethylsilane (SiC₃H₁₀), tetramethylsilane (SiC₄H₁₂), diethylsilane (SiC₄H₁₂), and combinations thereof.

41. The method of claim 25 wherein the silicon source and the carbon source are selected from the group consisting of silane (SiH₄), methane (CH₄), disilane (SiH₆), and combinations thereof.

42. The method of claim 25 wherein the nitrogen source is selected from the group consisting of ammonia (NH₃) and nitrogen (N₂), and combinations thereof.

43. The method of claim 25 wherein the gas mixture further comprises an inert gas.

44. The method of claim 43 wherein the inert gas is selected from the group consisting of helium (He), argon (Ar), neon (Ne), and combinations thereof.

45. The method of claim 25 wherein the ratio of the silicon source to the nitrogen source in the gas mixture has a range of about 1:

1 to about 1;

100.

46. The method of claim 25 wherein the substrate is heated to a temperature between about 150°

C. to about 450°

C.

47. The method of claim 25 wherein the deposition chamber is maintained at a pressure between about 1 torr to about 15 torr.

48. The method of claim 25 wherein either of the silicon source or the carbon source is provided to the deposition chamber at a flow rate within a range of about 10 sccm to about 4,000 sccm.

49. The method of claim 25 wherein the nitrogen source is provided to the deposition chamber at a flow rate in a range of about 50 sccm to about 10,000 sccm.

50. The method of claim 25 wherein the electric field is generated from one or more radio frequency (RF) powers.

51. The method of claim 50 wherein each of the one or more RF powers is in a range of about 1 watt/cm² to about 10 watts/cm².

52. The method of claim 25 wherein the nitrogen-containing silicon carbide layer has a dielectric constant less than about 5.5.

53. The method of claim 25 wherein the nitrogen-containing silicon carbide layer has a leakage current less than about 10⁻

9 A/cm² at 2 MV/cm.

54. The method of claim 25 wherein the nitrogen-containing silicon carbide layer has a compressibility greater than about 5×

10⁸ dynes/cm².

55. The method of claim 25, wherein the one or more inert gas is selected from the group consisting of helium (He), argon (Ar), neon (Ne), and combinations thereof.

56. The method of claim 25, wherein the process chamber is maintained at a pressure within a range of about 5 torr to about 10 torr.

57. The method of claim 25, wherein the one or more inert gas is provided to the deposition chamber at a flow rate within a range of about 1,000 sccm to about 7,000 sccm.

58. The method of claim 25, wherein the electric field is a radio frequency (RF) power.

59. The method of claim 58, wherein the RF power is within a range of about 1 watt/cm² to about 10 watts/cm².

60. The method of claim 25, further comprising forming a silicon carbide cap layer on the nitrogen-containing silicon carbide layer.

61. A method of fabricating a metal interconnect structure, comprising:

(a) providing a substrate having a metal layer thereon;

(b) forming a nitrogen-containing silicon carbide barrier layer on the metal layer, wherein the nitrogen-containing silicon carbide barrier layer is formed by reacting a gas mixture comprising a silicon source, a carbon source, and a nitrogen source in the presence of an electric field;

(c) forming a first dielectric layer on the nitrogen-containing silicon carbide barrier layer;

(d) forming a nitrogen-containing silicon carbide hard mask on the first dielectric layer, wherein the nitrogen-containing silicon carbide hard mask is formed by reacting a silicon source, a carbon source, and a nitrogen source in the presence of an electric field;

(e) patterning the nitrogen-containing silicon carbide hard mask to define vias therethrough;

(f) forming a second dielectric layer on the patterned nitrogen-containing silicon carbide hard mask;

(g) patterning the second dielectric layer to define interconnects therethrough, wherein the interconnects are positioned over the vias defined in the nitrogen-containing silicon carbide hard mask;

(h) transferring the via pattern through the first dielectric layer using the nitrogen containing silicon carbide hard mask as a mask; and

by (i) filling the vias and interconnects with a conductive material.

62. The method of claim 61 wherein the first dielectric layer and the second dielectric layer each have dielectric constants less than about 3.

63. The method of claim 61 wherein the nitrogen-containing silicon carbide barrier layer and the nitrogen-containing silicon carbide hard mask each have dielectric constants less than about 5.5.

64. The method of claim 61 wherein the conductive material filling the vias and interconnects has a resistivity less than about 5 μ

Ω

-cm (micro-ohms-centimeters).

65. The method of claim 61, wherein the first dielectric layer and the second dielectric layer are selected from the group consisting of silicon oxide and fluorosilicate glass (FSG).

66. The method of claim 61, wherein the conductive material filling the vias and the interconnects is selected from the group consisting of copper (Cu), aluminum (Al), tungsten (W), and combinations thereof.

67. The method of claim 61, wherein the metal layer on the substrate is selected from the group consisting of copper (Cu), aluminum (Al), tungsten (W), and combinations thereof.

68. The method of claim 61 wherein either of the silicon source or the carbon source of steps (b) and (d) comprise an organosilane compound having the general formula Si_xC_yH_x, wherein x has a range of 1 to 2, y has a range of 1 to 6, and z has a range of 4 to 18.

69. The method of claim 68 wherein the organosilane compound is selected from the group consisting of methylsilane (SiCH₆), dimethylsilane (SiC₂H₈), trimethylsilane (SiC₃H₁₀), tetramethylsilane (SiC₄H₁₂), diethylsilane (SiC₄H₁₂), and combinations thereof.

70. The method of claim 61, wherein either of the silicon source or the carbon source of steps (b) and (d) is selected from the group consisting of silane (SiH₄), methane (CH₄), disilane (Si₂H₆), and combinations thereof.

71. The method of claim 61, wherein the nitrogen source of steps (b) and (d) is selected from the group consisting of ammonia (NH₃), nitrogen (N₂), and combinations thereof.

72. The method of claim 61 wherein the gas mixture of steps (b) and (d) further comprises an inert gas.

73. The method of claim 72, wherein the inert gas is selected from the group consisting of helium (He), argon (Ar), neon (Ne), and combinations thereof.

74. The method of claim 61 wherein the ratio of the silicon source to the nitrogen source in the gas mixture of steps (b) and (d) has a range of about 1:

1 to about 1;

100.

75. The method of claim 61 wherein the substrate is heated to a temperature between about 150°

C. to about 450°

C. during steps (b) and (d).

76. The method of claim 61 wherein steps (b) and (d) are performed at a pressure within a range of about 1 torr to about 15 torr.

77. The method of claim 61 wherein either of the silicon source or the carbon source of steps (b) and (d) is provided to the deposition chamber at a flow rate in a range of about 10 sccm to about 4,000 sccm.

78. The method of claim 61 wherein the nitrogen source of steps (b) and (d) is provided to the deposition chamber at a flow rate in a range of about 50 sccm to about 10,000 sccm.

79. The method of claim 61 wherein the electric field is generated from one or more radio frequency (RF) powers.

80. The method of claim 79 wherein each of the one or more RF powers is in a range of about 1 watt/cm² to about 10 watts/cm².

81. The method of claim 61 wherein the nitrogen-containing silicon carbide hard mask is an antireflective coating (ARC) at wavelengths less than about 250 nm.

82. The method of claim 61 wherein the nitrogen-containing silicon carbide barrier layer and the nitrogen-containing silicon carbide hard mask each have leakage currents less than about 10⁻

9 A/cm² at 2 MV/cm.

83. The method of claim 61 wherein the nitrogen-containing silicon carbide barrier layer and the nitrogen-containing silicon carbide hard mask each have a compressibility greater than about 5×

10⁸ dynes/cm².

84. The method of claim 61, further comprising the step of plasma treating the nitrogen-containing silicon carbide barrier layer and the nitrogen-containing silicon carbide hard mask.

85. The method of claim 84 wherein either of the nitrogen-containing silicon carbide barrier layer and the nitrogen-containing silicon carbide hard mask are plasma treated by:

providing one or more inert gas to a process chamber having the substrate therein with the nitrogen-containing silicon carbide barrier layer or the nitrogen-containing silicon carbide hard mask formed thereon; and

applying an electric field to the one or more inert gas to generate a plasma in the process chamber.

86. The method of claim 85 wherein the one or more inert gas is selected from the group consisting of helium (He), argon (Ar), neon (Ne), and combinations thereof.

87. The method of claim 85 wherein the process chamber is maintained at a pressure in a range of about 5 torr to about 10 torr.

88. The method of claim 85 wherein the one or more inert gas is provided to the process chamber at a flow rate in a range of about 1,000 sccm to about 7,000 sccm.

89. The method of claim 85 wherein the electric field is a radio frequency (RF) power.

90. The method of claim 89 wherein the RF power is within a range of about 1 watt/cm² to about 10 watts/cm².