PLASMA APPARATUS, GAS DISTRIBUTION ASSEMBLY FOR A PLASMA APPARATUS AND PROCESSES THEREWITH

• US 20040238123A1
• Filed: 05/22/2003
• Published: 12/02/2004
• Est. Priority Date: 05/22/2003
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Axcelis Technologies Incorporated
• Inventors: Ferris, David, Becknell, Alan Frederick, Srivastava, Aseem Kumar, Waldfried, Carlo, Buckley, Thomas James, Pingree, Richard E. Jr., Sakthivel, Palanikumaran
• Granted Patent: US 8,580,076 B2
• Time in Patent Office: Days
• US Class Current: 156/345.33
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32844 Treating effluent gases
• CPC Class Codes: Y02C 20/30 of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]

Abstract

A plasma apparatus, various components of the plasma apparatus, and an oxygen free and nitrogen free processes for effectively removing photoresist material and post etch residues from a substrate with a carbon and/or hydrogen containing low k dielectric layer(s).

Claims

1. An axial flow downstream plasma treatment device for treating a substrate, comprising, in combination:

a gas source;

a plasma generating component in fluid communication with the gas source, the plasma generating component comprising a plasma tube and a plasma generator coupled to the plasma tube for generating a plasma within the plasma tube from the gas source;

a process chamber in fluid communication with the plasma tube comprising a baffle plate assembly about an inlet of the process chamber, wherein the baffle plate assembly comprises a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein a dimension of each one of the plurality of apertures increases from the central axis to an outer edge of the lower baffle plate, and wherein the baffle plate assembly is positioned generally parallel to the substrate; and

an exhaust conduit centrally located in a bottom wall of the process chamber.

2. The axial flow downstream plasma treatment device of claim 1, further comprising a gas purifier intermediate to the gas source and the plasma-generating component.

3. The axial flow downstream plasma treatment device of claim 1, further comprising at least one heating lamp positioned below the substrate and in optical communication with a bottom plate of the process chamber, wherein the bottom plate is formed from a material substantially transparent to visible and/or infrared radiation.

4. The axial flow downstream plasma treatment device of claim 1, further comprising an afterburner assembly coupled to the exhaust conduit, wherein the exhaust conduit comprises a gas port intermediate to the process chamber and the afterburner assembly.

5. The axial flow downstream plasma treatment device of claim 4, wherein the afterburner assembly comprises means for generating plasma in the exhaust conduit.

6. The axial flow downstream plasma treatment device of claim 5, wherein the afterburner assembly comprises an RF coil wrapped about an exterior of the exhaust conduit, a matchbox in electrical communication with the RF coil, and a power supply in electrical communication with the matchbox.

7. The axial flow downstream plasma treatment device of claim 1, further comprising an optical detection system coupled to the exhaust conduit.

8. The axial flow downstream plasma treatment device of claim 1, wherein the plasma generating component comprises a microwave enclosure partitioned into sections, wherein each section has an opening therein for receiving the plasma tube;

and means for providing microwave power of a predetermined frequency to the sections.

9. The axial flow downstream plasma treatment device of claim 1, wherein the gas source is substantially free from nitrogen and oxygen.

10. The axial flow downstream plasma treatment device of claim 1, further comprising a second gas source in fluid communication with the plasma tube, wherein the second gas source comprises an oxidizing gas for in situ cleaning of the process chamber.

11. The axial flow downstream plasma treatment device of claim 1, wherein the plasma tube has a smaller opening diameter than a diameter of the upper baffle plate.

12. The axial flow downstream plasma treatment device of claim 1, wherein the upper baffle plate comprises a central region free of apertures.

13. The axial flow downstream plasma treatment device of claim 1, wherein the upper baffle plate has a smaller diameter than the lower baffle plate, and wherein the upper baffle plate and an upper wall of the process chamber form a plenum therebetween.

14. The axial flow downstream plasma treatment device of claim 1, further comprising a loadlock chamber coupled to the process chamber;

and a sub-chamber in communication with the load lock chamber, wherein the sub-chamber comprises at least one robot arm having a primary pivot axis within the sub-chamber.

15. The axial flow downstream plasma treatment device of claim 1, further comprising a loadlock chamber and a cold plate disposed approximately in a center of the loadlock chamber.

16. An axial flow downstream plasma treatment device for treating a substrate, comprising, in combination:

a gas source;

a plasma generating component in fluid communication with the gas source, the plasma generating component comprising a plasma tube and a plasma generator coupled to the plasma tube for generating a plasma within the plasma tube from the gas source;

a process chamber in fluid communication with the plasma tube comprising a baffle plate assembly at about an inlet of the process chamber, wherein the baffle plate assembly comprises a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein the plurality of apertures increase in density from the central axis to an outer edge of the lower baffle plate; and

an exhaust conduit centrally located in a bottom wall of the process chamber.

17. The axial flow downstream plasma treatment device of claim 16, further comprising a gas purifier intermediate to the gas source and the plasma-generating component.

18. The axial flow downstream plasma treatment device of claim 16, further comprising at least one heating lamp positioned below the substrate and in optical communication with a bottom plate of the process chamber, wherein the bottom plate is formed from a material substantially transparent to infrared radiation.

19. The axial flow downstream plasma treatment device of claim 16, wherein the plasma tube has a smaller opening diameter than a diameter of the upper baffle plate.

20. The axial flow downstream plasma treatment device of claim 16, further comprising an afterburner assembly coupled to the exhaust conduit, wherein the exhaust conduit comprises a gas port intermediate to the process chamber and the afterburner assembly.

21. The axial flow downstream plasma treatment device of claim 20, wherein the afterburner assembly comprises means for generating plasma in the exhaust conduit.

22. The axial flow downstream plasma treatment device of claim 20, wherein the afterburner assembly comprises an RF coil wrapped about an exterior of the exhaust conduit, a matchbox in electrical communication with the RF coil, and a power supply in electrical communication with the matchbox.

23. The axial flow downstream plasma treatment device of claim 16, further comprising an optical detection system coupled to the exhaust conduit.

24. The axial flow downstream plasma treatment device of claim 16, wherein the plasma generator comprises a microwave enclosure partitioned into sections, wherein each section has an opening therein for receiving the plasma tube;

and means for providing microwave power of a predetermined frequency to the sections.

25. The axial flow downstream plasma treatment device of claim 16, wherein the gas source is substantially free from nitrogen and oxygen.

26. The axial flow downstream plasma treatment device of claim 16, further comprising a second gas source in fluid communication with the plasma tube, wherein the second gas source comprises an oxidizing gas for in situ cleaning of the process chamber.

27. The axial flow downstream plasma treatment device of claim 16, further comprising a loadlock chamber coupled to the process chamber;

and a sub-chamber in communication with the load lock chamber, wherein the sub-chamber comprises at least one robot arm having a primary pivot axis within the sub-chamber.

28. The axial flow downstream plasma treatment device of claim 16, further comprising a loadlock chamber and a cold plate disposed approximately in a center of the loadlock chamber.

29. An axial flow downstream plasma treatment device for treating a substrate containing a carbon and/or hydrogen containing low k dielectric layer, the plasma treatment device comprising, in combination:

a gas source comprising substantially nitrogen free and oxygen free gases;

a gas purifier in fluid communication with the gas source adapted to reduce nitrogen containing species and oxygen containing species from the substantially nitrogen free and oxygen free gases;

a plasma generating component in fluid communication with the gas purifier, the plasma generating component comprising a plasma tube and a plasma generator coupled to the plasma tube for generating a plasma within the plasma tube from the purified nitrogen free and oxygen free gases;

a process chamber in fluid communication with the plasma tube comprising a baffle plate assembly at an inlet of the process chamber;

an exhaust conduit centrally located in a bottom wall of the process chamber comprising a gas port in fluid communication with an oxidizing gas source;

an afterburner assembly coupled to the exhaust conduit and adapted to generate a an oxidizing plasma in the exhaust conduit; and

an optical detection system coupled to the exhaust conduit comprising collection optics focused within a plasma discharge region provided by the oxidizing plasma.

30. The axial flow downstream plasma treatment device of claim 29, wherein the exhaust conduit is formed of a material optically transparent to a wavelength monitored by the optical detection system.

31. The axial flow downstream plasma treatment device of claim 29, wherein the plasma generator comprises a microwave enclosure partitioned into sections, wherein each section has an opening therein for receiving the plasma tube;

and means for providing microwave power of a predetermined frequency to the sections.

32. The axial flow downstream plasma treatment device of claim 29, wherein the afterburner assembly comprises an RF coil wrapped about an exterior of the exhaust conduit, a matchbox in electrical communication with the RF coil, and a power supply in electrical communication with the matchbox.

33. The axial flow downstream plasma treatment device of claim 29, wherein the substantially nitrogen free and oxygen free gases comprises a hydrocarbon gas, hydrogen or helium or a combination comprising at least one of the foregoing gases.

34. The axial flow downstream plasma treatment device of claim 29, wherein the optical detection system comprises a spectrometer or a monochromator.

35. The axial flow downstream plasma treatment device of claim 29, further comprising a heating lamp array positioned below the substrate and in optical communication with a bottom plate of the process chamber, wherein the bottom plate is formed from a material substantially transparent to visible and/or infrared radiation emitted by the heating lamp array.

36. A plasma processing chamber for processing a substrate contained therein, comprising:

a baffle plate assembly comprising a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the upper baffle plate being smaller than the lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein a dimension of each one of the plurality of apertures increases from the central axis to an outer edge of the lower baffle plate, and wherein the baffle plate assembly is positioned generally parallel to the substrate.

37. The plasma processing chamber of claim 36, wherein the upper baffle plate contains a central portion free of apertures.

38. The plasma processing chamber of claim 36, wherein the upper baffle plate is formed of quartz, sapphire, ceramic, or sapphire coated quartz.

39. The plasma processing chamber of claim 36, wherein the upper baffle plate comprises a plurality of apertures.

40. The plasma processing chamber of claim 39, wherein the plurality of apertures in the upper baffle plate are larger in size than the plurality of apertures in the lower baffle plate.

41. The plasma processing chamber of claim 39, wherein the lower baffle plate is formed of anodized aluminum, sapphire, quartz, or a ceramic material.

42. A plasma processing chamber for processing a substrate contained therein, comprising:

a baffle plate assembly comprising a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the upper baffle plate being smaller than the lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein the plurality of apertures increase in density from the central axis to an outer edge of the lower baffle plate.

43. The plasma processing chamber of claim 42, wherein the upper baffle plate contains a central portion free of apertures.

44. The plasma processing chamber of claim 42, wherein the upper baffle plate is formed of quartz, sapphire, ceramic, or sapphire coated quartz.

45. The plasma processing chamber of claim 42, wherein the upper baffle plate comprises a plurality of apertures.

46. The plasma processing chamber of claim 45, wherein the plurality of apertures in the upper baffle plate are larger in size than the plurality of apertures in the lower baffle plate.

47. The plasma processing chamber of claim 42, wherein the lower baffle plate is formed of anodized aluminum, sapphire, quartz, or a ceramic material.

48. A baffle plate assembly for distributing gas flow into an adjacent process chamber containing a semiconductor wafer to be processed, comprising:

a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the upper baffle plate being smaller than the lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein the plurality of apertures increase in density from the central axis to an outer edge of the lower baffle plate.

49. The baffle plate assembly of claim 48, wherein the semiconductor wafer contains a carbon and/or hydrogen basedlow k dielectric layer.

50. The baffle plate assembly of claim 48, wherein the upper baffle plate is formed of a sapphire coated quartz material and the lower baffle plate is formed of anodized aluminum.

51. The baffle plate assembly of claim 48, wherein the upper baffle plate comprises a plurality of apertures in a concentric multiply circular pattern and an apertureless central region.

52. A baffle plate assembly for distributing gas flow into an adjacent process chamber containing a semiconductor wafer to be processed, comprising:

a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the upper baffle plate being smaller than the lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, and wherein a dimension of each one of the plurality of apertures increases from the central axis to an outer edge of the lower baffle plate.

53. The baffle plate assembly of claim 52, wherein the semiconductor wafer has a carbon and/or a hydrogen containing low k dielectric layer.

54. The baffle plate assembly of claim 52, wherein the upper baffle plate is formed of a quartz, sapphire, or a ceramic material and the lower baffle plate is formed of anodized aluminum, sapphire, quartz, or a ceramic material.

55. The baffle plate assembly of claim 54, wherein the quartz material further comprises a sapphire coating.

56. The baffle plate assembly of claim 52, wherein the upper baffle plate comprises a plurality of apertures in a concentric multiply circular pattern and an apertureless central region.

57. A process for uniformly distributing excited species generated in an oxygen free and nitrogen free plasma onto a substrate, comprising:

introducing the excited species into a plasma processing chamber, wherein the plasma processing chamber comprises a baffle plate assembly for receiving the excited species, the baffle plate assembly comprising a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, and wherein a dimension of each one of the plurality of apertures increases from the central axis to an outer edge of the lower baffle plate; and

exposing the substrate to the excited species after flowing through the baffle plate assembly.

58. A process for uniformly distributing excited species generated in an oxygen free and nitrogen free plasma onto a substrate, comprising:

introducing the excited species into a plasma processing chamber, wherein the plasma processing chamber comprises a baffle plate assembly for receiving the excited species, the baffle plate assembly comprising a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein the plurality of apertures increase in density from the central axis to an outer edge of the lower baffle plate; and

exposing the substrate to the excited species after flowing through baffle plate assembly.

59. A plasma ashing process for removing photoresist material and post etch residues from a substrate with a carbon and/or hydrogen containing low k dielectric layer, the process comprising:

flowing a substantially oxygen free and nitrogen free gas into a gas purifier to form a purified gas with reduced levels of contaminants;

forming a plasma from the purified gas;

introducing the plasma into a process chamber, wherein the process chamber comprises a baffle plate assembly for receiving the plasma, the baffle plate assembly comprising a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein the plurality of apertures increase in density from the central axis to an outer edge of the lower baffle plate;

flowing the plasma through the baffle plate assembly and exposing the substrate to remove the photoresist material post etch residues, and volatile byproducts from substrate;

exhausting the removed photoresist material, post etch residues, and volatile byproducts into a centrally located exhaust conduit in the process chamber;

selectively introducing an oxidizing gas into the exhaust conduit;

forming a plasma from the oxidizing gas and the removed photoresist material, post etch residues, and volatile byproducts;

optically monitoring an emission signal produced in the exhaust conduit plasma; and

detecting an endpoint of the photoresist and post etch residues from an observed change in the emission signal.

60. The plasma ashing process of claim 59, wherein the substantially oxygen free and nitrogen free gas comprises hydrogen or helium or argon or neon or a combination comprising at least one of the foregoing gases.

61. The plasma ashing process of claim 59, wherein flowing the substantially oxygen free and nitrogen free gas into the gas purifier to form the purified gas comprises reducing levels of H₂O, O₂, CO, CO₂, and N₂ in the oxygen free and nitrogen free gas to an amount less than about 10 parts per million.

62. The plasma ashing process of claim 59, further comprising removing the substrate from the process chamber to a loadlock chamber and cooling the substrate.

63. A plasma ashing process for removing photoresist material and post etch residues from a substrate containing a carbon and/or hydrogen containing low k dielectric layer, the process comprising:

flowing a substantially oxygen free and nitrogen free gas into a gas purifier to form a purified gas with reduced levels of contaminants;

forming a plasma from the purified gas;

introducing the plasma into a process chamber, wherein the process chamber comprises a baffle plate assembly for receiving the plasma, the baffle plate assembly comprising a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, and wherein a dimension of each one of the plurality of apertures increases from the central axis to an outer edge of the lower baffle plate;

flowing the plasma through the baffle plate assembly and exposing the substrate to remove the photoresist material, post etch residues, and volatile byproducts from substrate;

exhausting the removed photoresist material, post etch residues, and volatile byproducts into a centrally located exhaust conduit in a bottom wall of the process chamber;

selectively introducing an oxidizing gas into the exhaust conduit;

forming a plasma from the oxidizing gas and the removed photoresist material, post etch residues, and volatile byproducts;

optically monitoring an emission signal produced in the exhaust conduit plasma; and

detecting an endpoint of the photoresist and post etch residues from an observed change in the emission signal.

64. The plasma ashing process of claim 63, wherein the substantially oxygen free and nitrogen free gas comprises hydrogen or helium or argon or neon or a combination comprising at least one of the foregoing gases.

65. A downstream plasma treatment device for treating a substrate, comprising, in combination:

a gas source;

a plasma generating component in fluid communication with the gas source, the plasma generating component comprising a plasma tube and a plasma generator coupled to the plasma tube for generating a plasma within the plasma tube from the gas source;

a process chamber in fluid communication with the plasma tube; and

a gas purifier intermediate to the gas source and the plasma generator.

66. The plasma treatment device of claim 65, wherein the process chamber further comprises a baffle plate assembly at about an inlet of the process chamber, wherein the baffle plate assembly comprises a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein a dimension of each one of the plurality of apertures increases from the central axis to an outer edge of the lower baffle plate, and wherein the baffle plate assembly is positioned generally parallel to the substrate.

67. The plasma treatment device of claim 65, wherein the process chamber further comprises a baffle plate assembly at about an inlet of the process chamber, wherein the baffle plate assembly comprises a generally planar upper baffle plate fixedly positioned above a generally planar lower baffle plate, the lower baffle plate comprising a plurality of apertures disposed about a central axis, wherein the plurality of apertures increase in density from the central axis to an outer edge of the lower baffle plate.

68. The plasma treatment device of claim 65, further comprising at least one heating lamp positioned below the substrate and in optical communication with a bottom plate of the process chamber, wherein the bottom plate is formed from a material substantially transparent to visible and/or infrared radiation.

69. The plasma treatment device of claim 65, further comprising an exhaust conduit centrally located in a bottom wall of the process chamber, wherein the exhaust conduit further comprises an afterburner assembly coupled to the exhaust conduit.

70. The plasma treatment device of claim 69, wherein the afterburner assembly comprises means for generating plasma in the exhaust conduit.

71. The plasma treatment device of claim 69, wherein the afterburner assembly comprises an RF coil wrapped about an exterior of the exhaust conduit, a matchbox in electrical communication with the RF coil, and a power supply in electrical communication with the matchbox.

72. The plasma treatment device of claim 69, further comprising an optical detection system coupled to the exhaust conduit.

73. The plasma treatment device of claim 65, wherein the plasma generating component comprises a microwave enclosure partitioned into sections, wherein each section has an opening therein for receiving the plasma tube;

and means for providing microwave power of a predetermined frequency to the sections.

74. The plasma treatment device of claim 65, wherein the gas source is substantially free from nitrogen and oxygen.

75. The plasma treatment device of claim 65, wherein the gas source consists essentially of hydrogen and helium.

76. The plasma treatment device of claim 65, further comprising a second gas source in fluid communication with the plasma tube, wherein the second gas source comprises an oxidizing gas for in situ cleaning of the process chamber and is not in fluid communication with the gas purifier.

77. The plasma treatment device of claim 66, wherein the plasma tube has a smaller opening diameter than a diameter of the upper baffle plate.

78. The plasma treatment device of claim 66, wherein the upper baffle plate comprises a central region free of apertures and a plurality of apertures disposed about the central region.

79. The plasma treatment device of claim 66, wherein the upper baffle plate has a smaller diameter than the lower baffle plate, and wherein the upper baffle plate and an upper wall of the process chamber form a plenum therebetween.

80. The plasma treatment device of claim 65, further comprising a loadlock chamber coupled to the process chamber;

and a sub-chamber in communication with the load lock chamber, wherein the sub-chamber comprises at least one robot arm having a primary pivot axis within the sub-chamber.

81. The plasma treatment device of claim 65, further comprising a loadlock chamber and a cold plate disposed approximately in a center of the loadlock chamber.