Supercritical fluid cleaning of semiconductor substrates

• US 20030125225A1
• Filed: 11/25/2002
• Published: 07/03/2003
• Est. Priority Date: 12/31/2001
• Status: Active Grant

• Current Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Original Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Inventors: Xu, Chongying, Korzenski, Michael B., Baum, Thomas H., Roeder, Jeffrey F., Minsek, David W.
• Granted Patent: US 7,326,673 B2
• Time in Patent Office: Days
• US Class Current: 510/175
• CPC Class Codes: B08B 7/0021 by liquid gases or supercritical fluids
• CPC Class Codes: C11D 2111/22 Electronic devices, e.g. PCBs or semiconductors
• CPC Class Codes: C11D 3/02 Inorganic compounds ; Elemental compounds
• CPC Class Codes: C11D 3/044 Hydroxides or bases
• CPC Class Codes: C11D 3/43 Solvents
• CPC Class Codes: C11D 7/02 Inorganic compounds
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: G03F 7/422 using liquids only G03F7/421 takes precedence
• CPC Class Codes: G03F 7/425 containing mineral alkaline compounds; containing organic basic compounds, e.g. quaternary ammonium compounds; containing heterocyclic basic compounds containing nitrogen
• CPC Class Codes: G03F 7/426 containing organic halogen compounds; containing organic sulfonic acids or salts thereof; containing sulfoxides

Abstract

Chemical formulations and methods for removing unwanted material, such as unexposed photoresist, metal oxides, CMP residue, and the like, from semiconductor wafers or other substrates. The formulations utilize a supercritical fluid-based cleaning composition, which may further include (I) co-solvent(s), (II) surfactant(s), (III) chelating agent(s), and/or (IV) chemical reactant(s).

Claims

1. A cleaning formulation useful for removing unwanted material from a surface having such unwanted material thereon, said cleaning formulation comprising a supercritical fluid, at least one co-solvent, and at least one additional active agent.

2. The cleaning formulation according to claim 1, wherein the supercritical fluid comprises a fluid selected from the group consisting of:

carbon dioxide, oxygen, argon, ammonia, and mixtures thereof.

3. The cleaning formulation according to claim 1, wherein the supercritical fluid comprises carbon dioxide.

4. The cleaning formulation according to claim 1, wherein said at least one co-solvent comprises a co-solvent selected from the group consisting of:

methanol, ethanol, isopropyl alcohol, N-methylpyrrolidone, N-octylpyrrolidone, N-phenylpyrrolidone, dimethylsulfoxide, sulfolane, catechol, ethyl lactate, acetone, butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine, alkyl ammonium fluoride, ybutyrolactone, butylene carbonate, ethylene carbonate, and propylene carbonate.

5. The cleaning formulation according to claim 1, further comprising at least one surfactant.

6. The cleaning formulation according to claim 5, wherein the at least one surfactant comprises a surfactant selected from the group consisting of:

3,4-dimethyl-1-hexyn-3-ol and 2,4,7,9-tetramethyl-5-decyn-4,7-diol.

7. The cleaning formulation according to claim 1, further comprising at least one chelating agent.

8. The cleaning formulation according to claim 7, wherein the at least one chelating agent comprises a chelating agent selected from the group consisting of:

iminodiacetic acid, lauryl ethylenediamine triacetic acid, 2,4-pentanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.

9. The cleaning formulation according to claim 1, wherein said at least one additional active agent comprises an acid that is effective to remove metal oxide material when same is present as the unwanted material on said surface.

10. The cleaning formulation according to claim 9, wherein said acid is selected from the group consisting of:

perfluorocarboxylic acids, alkyl sulfonic acids, and aryl sulfonic acids.

11. The cleaning formulation according to claim 1, wherein the active agent comprises a reducing agent that is effective to remove metal oxide material when same is present as the unwanted material on said surface.

12. The cleaning formulation according to claim 11, wherein the reducing agent comprises an agent selected from the group consisting of hydrogen, ammonia, silanes, hydrides and metal hydrides.

13. The cleaning formulation according to claim 11, wherein the reducing agent is activated by a modality selected from the group consisting of thermal activation, optical activation, and sonic activation.

14. The cleaning formulation according to claim 11, wherein said metal oxide material comprises copper oxide.

15. A semiconductor wafer cleaning formulation useful to remove non-irradiated photoresist from a semiconductor wafer surface having irradiated and non-irradiated photoresist regions thereon, said formulation comprising an etching gas in supercritical form.

16. The cleaning formulation according to claim 15, wherein the etching gas comprises an etching agent selected from the group consisting of sulfur hexafluoride, carbon tetrafluoride and xenon difluoride.

17. The cleaning formulation according to claim 15, further comprising another component in supercritical fluid form.

18. The cleaning formulation according to claim 17, wherein the additional supercritical fluid component comprises a fluid species selected from the group consisting of carbon dioxide, oxygen, argon, and ammonia.

19. The cleaning formulation according to claim 17, wherein the additional supercritical fluid component comprises carbon dioxide.

20. The cleaning formulation according to claim 17, wherein the formulation is activated by thermal and/or optical activation.

21. The cleaning formulation according to claim 15, further comprising a co-solvent.

22. The cleaning formulation according to claim 15, further comprising a surfactant.

23. The cleaning formulation according to claim 15, further comprising an active agent.

24. The cleaning formulation according to claim 15, further comprising a chelating agent.

25. A cleaning formulation for removing unwanted solid deposited material from a surface of a substrate having the unwanted solid deposited material thereon, said cleaning formulation comprising

(I) a supercritical fluid comprising a fluid species selected from the group consisting of carbon dioxide, oxygen, argon, ammonia, and mixtures thereof, and

(II) a co-solvent comprising a co-solvent species selected from the group consisting of methanol, ethanol, and higher alcohols, N-alkylpyrrolidones, such as N-methyl-, N-octyl-, or N-phenyl-pyrrolidones, dimethylsulfoxide, sulfolane, catechol, ethyl lactate, acetone, butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine, alkyl ammonium fluoride, γ

-butyrolactone, butylene carbonate, ethylene carbonate, and propylene carbonate.

26. The cleaning formulation of claim 25, further comprising at least one surfactant.

27. The cleaning formulation of claim 25, further comprising at least one surfactant selected from the group consisting of acetylenic alcohols and diols, and long alkyl chain secondary and tertiary amines

28. The cleaning formulation of claim 25, further comprising at least one chelating agent.

29. The cleaning formulation of claim 25, further comprising at least one chelating agent selected from the group consisting of polycarboxylic acids, P-diketones, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.

30. The cleaning formulation of claim 25, further comprising at least one chelating agent selected from the group consisting of iminodiacetic acid, lauryl ethylenediamine triacetic acid, 2,4-pentanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4pentanedione, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.

31. The cleaning formulation of claim 25, further comprising at least one active agent.

32. The cleaning formulation of claim 25, further comprising at least one active agent selected from the group consisting of (a) acids, (b) bases, (c) oxidants, and (d) reductants.

33. The cleaning formulation of claim 25, further comprising at least one active agent selected from the group consisting of HF sources, fluoride sources, perfluorocarboxylic acids, alkyl sulfonic acids, aryl sulfonic acids, alkyl amines, ozone, dinitrogen oxide, potassium permanganate, and hydrogen.

34. A method for fabricating a semiconductor wafer, said method comprising removing unwanted material from the surface of the wafer with a cleaning formulation comprising a supercritical fluid, at least one co-solvent, and at least one additional active agent.

35. The method according to claim 34, wherein the supercritical fluid comprises a fluid selected from the group consisting of:

carbon dioxide, oxygen, argon, ammonia, and mixtures thereof.

36. The method according to claim 34, wherein the supercritical fluid comprises carbon dioxide.

37. The method according to claim 34, wherein said at least one co-solvent comprises a cosolvent selected from the group consisting of:

methanol, ethanol, isopropyl alcohol, N-methylpyrrolidone, N-octylpyrrolidone, N-phenylpyrrolidone, dimethylsulfoxide, sulfolane, catechol, ethyl lactate, acetone, butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine, alkyl ammonium fluoride, γ

-butyrolactone, butylene carbonate, ethylene carbonate, and propylene carbonate.

38. The method according to claim 34, wherein the cleaning formulation includes at least one surfactant.

39. The method according to claim 38, wherein the at least one surfactant comprises a surfactant selected from the group consisting of:

3,4-dimethyl-1-hexyn-3-ol and 2,4,7,9tetramethyl-5-decyn-4,7-diol.

40. The method according to claim 34, wherein the cleaning formulation further comprises at least one chelating agent.

41. The method according to claim 40, wherein the at least one chelating agent comprises a chelating agent selected from the group consisting of:

iminodiacetic acid, lauryl ethylenediamine triacetic acid, 2,4-pentanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.

42. The method according to claim 34, wherein said at least one additional active agent comprises an acid that is effective to remove metal oxide material when same is present as the unwanted material on said surface.

43. The method according to claim 42, wherein said acid is selected from the group consisting of:

perfluorocarboxylic acids, alkyl sulfonic acids, and aryl sulfonic acids.

44. The method according to claim 34, wherein the active agent comprises a reducing agent that is effective to remove metal oxide material when same is present as the unwanted material on said surface.

45. The method according to claim 44, wherein the reducing agent comprises an agent selected from the group consisting of hydrogen, ammonia, silanes, hydrides and metal hydrides.

46. The method according to claim 44, wherein the reducing agent is activatable by an activation modality selected from the group consisting of thermal activation, optical activation, and sonic activation.

47. The method according to claim 44, wherein said metal oxide material comprises copper oxide.

48. A method of removing non-irradiated photoresist from a semiconductor wafer surface having irradiated and non-irradiated photoresist regions thereon, comprising contacting the semiconductor wafer surface with an etching gas in supercritical form.

49. The method according to claim 48, wherein the etching gas comprises an etching agent selected from the group consisting of sulfur hexafluoride, carbon tetrafluoride and xenon difluoride.

50. The method according to claim 48, wherein the cleaning formulation further comprises another component in supercritical fluid form.

51. The method according to claim 50, wherein the additional supercritical fluid component comprises a fluid species selected from the group consisting of carbon dioxide, oxygen, argon, and ammonia.

52. The method according to claim 50, wherein the additional supercritical fluid component comprises carbon dioxide.

53. The method according to claim 48, wherein the cleaning formulation is activatable by thermal and/or optical activation.

54. The method according to claim 48, wherein the cleaning formulation further comprises a co-solvent.

55. The method according to claim 48, wherein the cleaning formulation further comprises a surfactant.

56. The method according to claim 48, wherein the cleaning formulation further comprises an active agent.

57. The method according to claim 48, wherein the cleaning formulation further comprises a chelating agent.

58. A method for removing unwanted solid deposited material from a surface of a substrate having the unwanted solid deposited material thereon, comprising contacting the substrate surface with a cleaning formulation comprising

(I) a supercritical fluid comprising a fluid species selected from the group consisting of carbon dioxide, oxygen, argon, ammonia, and mixtures thereof;

and

(II) a co-solvent comprising a co-solvent species selected from the group consisting of methanol, ethanol, and higher alcohols, N-alkylpyrrolidones, such as N-methyl-, N-octyl-, or N-phenyl-pyrrolidones, dimethylsulfoxide, sulfolane, catechol, ethyl lactate, acetone, butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine, alkyl ammonium fluoride, γ

-butyrolactone, butylene carbonate, ethylene carbonate, and propylene carbonate.

59. The method of claim 58, wherein the cleaning formulation further includes at least one surfactant.

60. The method of claim 58, wherein the cleaning formulation further includes at least one surfactant selected from the group consisting of acetylenic alcohols and diols, and long alkyl chain secondary and tertiary amines

61. The method of claim 58, wherein the cleaning formulation further includes at least one chelating agent.

62. The method of claim 58, wherein the cleaning formulation further includes at least one chelating agent selected from the group consisting of polycarboxylic acids, β

-diketones, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.

63. The method of claim 58, wherein the cleaning formulation further includes at least one chelating agent selected from the group consisting of iminodiacetic acid, lauryl ethylenediamine triacetic acid, 2,4-pentanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.

64. The method of claim 58, wherein the cleaning formulation further includes at least one active agent.

65. The method of claim 58, wherein the cleaning formulation further includes at least one active agent selected from the group consisting of (a) acids, (b) bases, (c) oxidants, and (d) reductants.

66. The method of claim 58, wherein the cleaning formulation further includes at least one active agent selected from the group consisting of HR sources, fluoride sources, perfluorocarboxylic acids, alkyl sulfonic acids, aryl sulfonic acids, alkyl amines, ozone, dinitrogen oxide, potassium permanganate, and hydrogen.

67. A method of integrated circuit (IC) manufacture on a semiconductor substrate, comprising cleaning the semiconductor substrate to remove organic and/or inorganic material present thereon, wherein said cleaning comprises contacting the semiconductor substrate with a supercritical fluid-based cleaning composition including at least one of (I) co-solvent(s), (II) surfactant(s), (III) chelating agent(s), and (IV) chemical reactant(s).

68. A method of integrated circuit (IC) manufacture on a semiconductor substrate, comprising cleaning the semiconductor substrate to remove organic and/or inorganic material present thereon, wherein said cleaning comprises contacting the semiconductor substrate with a supercritical fluid-based cleaning composition to permeate same into the material, and heating the semiconductor substrate to induce removal of the material therefrom by the action of the supercritical fluid-based cleaning composition.

69. A method of integrated circuit (IC) manufacture on a semiconductor substrate, comprising cleaning the semiconductor substrate to remove organic and/or inorganic material present thereon, wherein said cleaning comprises contacting the semiconductor substrate with a supercritical fluid-based cleaning composition in a pulsed mode of operation involving intermittent administration of energy to the cleaning composition on the semiconductor substrate.

70. A method of removing non-irradiated photoresist from a semiconductor wafer surface having irradiated and non-irradiated photoresist regions thereon, comprising contacting the semiconductor wafer surface with an etching agent in the presence of a supercritical fluid.

71. A method of cleaning a printed circuit board surface of unwanted metal oxides thereon, comprising contacting the printed circuit board surface with a cleaning formulation comprising an acid dissolved in a supercritical fluid.

72. A method of cleaning a surface of unwanted material deposited thereon, comprising contacting the surface with a cleaning formulation comprising a reducing agent in a supercritical fluid.

73. The method of claim 72, wherein the cleaning formulation is activated by an activation modality selected from the group consisting of thermal activation, optical activation and sonic activation, to effect cleaning action on the surface.

74. The method of claim 72, wherein the unwanted material comprises copper oxide.

75. The method of claim 72, wherein the unwanted material comprises unexposed photoresist.

76. A method of surface treatment of a substrate to produce a modified surface amenable to further processing, said method comprising contacting the substrate surface with a modifying composition comprising a supercritical fluid and at least one surface-modifying component effective to change the chemical properties of the substrate surface, or to protect underlying material or structure associated with such substrate surface.

77. The method of claim 76, wherein the at least one surface-modifying component comprises a long-chain organic material.

78. The method of claim 76, wherein the at least one surface-modifying component comprises at least one long-chain compound selected from the group consisting of long-chain organothiols, long-chain acetates and long-chain amines.

79. The method of claim 76, wherein the SCF component comprises supercritical CO₂.

80. A surface modification composition for modifying the chemical properties of a substrate surface or to protect underlying material or structure associated with the substrate surface, said composition comprising an SCF and a long-chain organic material.

81. The composition of claim 80, wherein said long-chain organic material comprises an organic component selected from the group consisting of long-chain organothiols, long-chain acetates and long-chain amines.

82. A method of removing water from a substrate after development of aqueous developed photoresist thereon, without image collapse or degradation, comprising contacting the substrate with a cleaning composition containing a supercritical fluid and at least one additional component selected from the group consisting of co-solvent(s), active agent(s), surfactant(s) and chelating agent(s).

83. The method of claim 82, wherein the aqueous developed photoresist has a dimensional characteristic of <

0.09 μ

m.

84. A composition comprising CO₂ and at one semiconductor processing etchant, wherein said CO₂ and said at least one semiconductor processing etchant are present in said composition as supercritical fluids.

85. The composition of claim 84, wherein said at least one semiconductor processing etchant comprises at least one perfluorocarbon species.

86. The composition of claim 85, wherein said at least one perfluorocarbon species comprises at least one of SF₆ and CF₄.

87. A cleaning composition, comprising supercritical CO₂, isopropanol, and ammonium fluoride.

88. The cleaning composition of claim 87, wherein isopropanol is present at a concentration of from about 0.005 to about 20 wt. %, based on total weight of the composition.

89. The cleaning composition of claim 88, wherein ammonium fluoride is present at a concentration of from about 0.005 to about 5.0 wt. %, based on total weight of the composition.

90. A method of cleaning a semiconductor substrate to remove unwanted material therefrom, said method comprising contacting the semiconductor substrate with a cleaning composition comprising supercritical CO₂, isopropanol, and ammonium fluoride.

91. The method of claim 90, wherein said contacting is carried out for a duration of up to about 900 seconds.

92. The method of claim 90, wherein said contacting is carried out for a duration of from about 30 to about 900 seconds.