Inductively coupled RF plasma reactor having an overhead solenoidal antenna and modular confinement magnet liners

• US 6,074,512 A
• Filed: 07/15/1997
• Issued: 06/13/2000
• Est. Priority Date: 06/27/1991
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Collins, Kenneth, Schneider, Gerhard, Rice, Michael, Yin, Gerald, Wu, Robert, Grimard, Dennis, Tsui, Joshua, Buchberger, Douglas, Trow, John, Roderick, Craig, Askarinam, Eric
• Primary Examiner(s): MCDONALD, RODNEY GLENN
• Application Number:
  US08/893,393
• Time in Patent Office: 1,064 Days
• Field of Search: 204/298.06, 204/298.07, 204/298.15, 204/298.16, 204/298.31, 204/298.33, 204/298.34, 204/298.37, 204/298.09, 156/345, 118/723 MP, 118/723 MR, 118/723 MA, 118/723 AN, 118/723 E, 118/723 I, 118/723 IR, 118/724, 118/728
• US Class Current: 156/345.29
• CPC Class Codes: C23C 16/517 using a combination of discharges covered by two or more of groups C23C16/503 - C23C16/515
• CPC Class Codes: H01F 2029/143 with control winding for generating magnetic bias
• CPC Class Codes: H01J 2237/3343 Problems associated with etching
• CPC Class Codes: H01J 2237/3345 anisotropy
• CPC Class Codes: H01J 2237/3346 Selectivity
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32146 Amplitude modulation, includes pulsing
• CPC Class Codes: H01J 37/32165 Plural frequencies
• CPC Class Codes: H01J 37/32458 Vessel
• CPC Class Codes: H01J 37/32467 Material
• CPC Class Codes: H01J 37/32522 Temperature
• CPC Class Codes: H01J 37/32688 Multi-cusp fields
• CPC Class Codes: H01J 37/32706 Polarising the substrate
• CPC Class Codes: H01J 37/32871 Means for trapping or directing unwanted particles
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/6831 using electrostatic chucks

Abstract

In accordance with a first aspect of the invention, a plasma reactor having a chamber for containing a plasma and a passageway communicating with the chamber is enhanced with a first removable plasma confinement magnet module placed adjacent the passageway including a first module housing and a first plasma confinement magnet inside the housing. It may further include a second removable plasma confinement magnet module placed adjacent the passageway including a second module housing, and a second plasma confinement magnet. Preferably, the first and second modules are located on opposite sides of the passageway. Moreover, the first and second plasma confinement magnets have magnetic orientations which tend to oppose plasma transport or leakage through the passageway. Preferably, the module housing includes a relatively non-magnetic thermal conductor such as aluminum and is in thermal contact with said chamber body. Cooling apparatus can be thermally coupled to the chamber body, whereby to maintain the first plasma confinement magnet below its Curie temperature. If the reactor includes a pumping annulus adjacent of a periphery of the chamber, then the passageway can be one which communicates between the chamber and the pumping annulus. Also, the passageway can be a wafer slit valve or a gas feed inlet. Such a gas feed inlet can be a center gas feed through a ceiling of the chamber. The module housing can rest upon the chamber side wall and the chamber ceiling can rest upon the module housing.

Claims

1. A plasma reactor comprising:

a chamber for containing a plasma;

a passageway communicating with said chamber;

a first removable plasma confinement magnet module placed adjacent said passageway, said first module comprising;

a first module housing, and

a first plasma confinement magnet inside said housing.

2. The reactor of claim 1 further comprising a second removable plasma confinement magnet module placed adjacent said passageway, said second module comprising:

a second module housing, and

a second plasma confinement magnet.

3. The reactor of claim 2 wherein said first and second modules are located on opposite sides of said passageway.

4. The reactor of claim 3 wherein said first and second plasma confinement magnets have magnetic orientations which tend to oppose plasma transport or leakage through said passageway.

5. The reactor of claim 1 wherein said first module housing comprises a non-magnetic thermal conductor.

6. The reactor of claim 5 wherein said first module comprises aluminum.

7. The reactor of claim 5 wherein said chamber comprises a chamber body, and wherein said first module housing is in thermal contact with said chamber body.

8. The reactor of claim 7 further comprising a cooling apparatus thermally coupled to said first module housing via said chamber body, whereby to maintain the first plasma confinement magnet below its Curie temperature.

9. The reactor of claim 1 wherein said reactor further comprises a pumping annulus adjacent of a periphery of said chamber, and wherein said passageway comprises a passageway communicating between said chamber and said pumping annulus.

10. The reactor of claim 1 wherein said passageway comprises a wafer slit valve.

11. The reactor of claim 1 wherein said passageway comprises a gas feed inlet.

12. The reactor of claim 11 wherein said gas feed inlet comprises a center gas feed through a ceiling of said chamber.

13. The reactor of claim 1 wherein said reactor further comprises a chamber side wall and a chamber ceiling, and wherein said first module housing rests upon said side wall and said ceiling rests upon said first module housing.

14. The reactor of claim 5 wherein said first module housing comprises an opening, said first magnet located inside said opening, said first module housing further comprising:

a bonding layer attaching said first magnet to an interior surface inside said opening, and

a cover plate covering said opening so as to seal said first magnet inside said first module housing.

15. The reactor of claim 14 further comprising a welding bond between said cover plate and said first module housing.

16. The reactor of claim 15 wherein said welding bond is produced by one of:

(a) E-beam welding, (b) laser welding.

17. A plasma reactor comprising:

a reactor chamber enclosure including a ceiling;

plural cooling rings resting on top of said ceiling;

a cold plate overlying said plural cooling rings; and

an elastically deformable thermally conductive layer between each one of said plural cooling rings and said cold plate.

18. The reactor of claim 17 wherein said elastically deformable thermally conductive layer comprises Grafoil.

19. The reactor of claim 17 further comprising an RF reflector coating between said elastically deformable thermally conductive layer and each cooling ring.

20. The reactor of claim 19 wherein said RF reflector coating is thermally conductive.

21. The reactor of claim 20 wherein said RF reflector coating is electrically conductive.

22. The reactor of claim 21 wherein said RF reflector coating comprises aluminum.

23. The reactor of claim 19 further comprising an RF power applicator between said cold plate and said ceiling capable of coupling RF power into said chamber through said ceiling, whereby said reflector coating reflects RF power to prevent its absorption by said elastically deformable thermally conductive layer.

24. A plasma reactor comprising:

a reactor chamber;

an electrostatic chuck for supporting a workpiece inside said chamber; and

at least one semiconductor grounding pin for electrostatically discharging a wafer, said grounding pin extending through said electrostatic chuck toward a plane whereon said chuck is capable of supporting said workpiece, said pin being movable between an extended position at which said pin can contact said workpiece and a retracted position.

25. The reactor of claim 24 further comprising a frame supporting said pin, said frame being connectable to a ground potential.

26. The reactor of claim 25 further comprising an actuator for moving said frame whereby to transport said pin between said extended and retracted positions.

27. The reactor of claim 24 wherein said pin comprises silicon.

28. The reactor of claim 24 wherein said pin comprises silicon carbide.

29. The reactor of claim 24 further comprising a dielectric layer overlying said electrostatic chuck for insulating said workpiece from said chuck.

31. The reactor of claim 24 further comprising a semiconductor collar around a periphery of said electrostatic chuck.

32. The reactor of claim 31 wherein said semiconductor collar comprises silicon carbide.

33. The reactor of claim 31 further comprising a heated flourine scavenging ring surrounding said electrostatic chuck.

30. The reactor of claim wherein said electrostatic chuck is alternately connectable to a ground potential and to a voltage source and wherein said semiconductor pin is connected to a ground potential.

34. A plasma reactor comprising:

a chamber;

a workpiece chuck for supporting a workpiece inside said chamber;

an RF power applicator and gas inlet apparatus for admitting a process gas into said chamber;

a semiconductor ring surrounding said workpiece chuck and heating apparatus for heating said semiconductor ring; and

a slit in said semiconductor ring for permitting thermal expansion of said semiconductor ring.

35. The plasma reactor of claim 34 wherein said semiconductor ring comprises one of (a) silicon carbide and (b) silicon.

36. The plasma reactor of claim 34 wherein said heating apparatus comprises plural radiant heat lamps underlying said semiconductor ring.

37. A plasma reactor comprising:

a chamber including a ceiling;

a pedestal for supporting a workpiece inside said chamber;

process gas inlet apparatus;

an inductive antenna comprising plural stacked coil windings, each of said coil windings residing generally in a respective one of plural parallel planes, the windings in adjacent planes being connected at a step region common to all said planes wherein each winding transitions from one plane to a next plane, said coil windings being formed of a single conductor having a pair of connection sections, a first one of said connection sections extending from a top-most one of said windings and a second one of said connection sections extending from a bottom-most one of said windings, said first one of said connection sections extending upwardly away from said top-most winding, said second one of said connection sections following an arcuate path upwardly from said bottom-most winding to said top-most winding so as to provide an effective number of stacked windings which is generally uniform along said step region.

38. The plasma reactor of claim 37 wherein said arcuate path is such that said second one of said connection sections is generally parallel to said parallel planes adjacent said bottom-most winding and is generally perpendicular to said parallel planes adjacent said top-most winding.

39. A plasma reactor comprising:

a chamber including a ceiling;

a pedestal for supporting a workpiece inside said chamber;

process gas inlet apparatus;

an inductive antenna comprising plural stacked coil windings, each of said coil windings residing generally in a respective one of plural parallel planes, the windings in adjacent planes being connected at a step region common to all said planes wherein each winding transitions from one plane to a next plane, said antenna further comprising a conductor coupled to a bottom-most one of said windings extending upwardly from one azimuthal end of said step region to a second azimuthal end of said step region toward the plane of a top-most one of said windings.

40. The reactor of claim 39 wherein said upwardly extending conductor follows an upwardly curving arcuate path.

41. A plasma reactor comprising:

a plasma reactor chamber and a workpiece support for holding a workpiece adjacent a support plane inside said chamber during processing, said chamber having a reactor enclosure portion facing said workpiece;

an inductive antenna adjacent and on an exterior side of said reactor enclosure portion and having more than two respective inductive elements, said respective inductive elements being at respective radial locations, said antenna being adapted to couple power into said chamber;

a passageway communicating with said chamber;

a first removable plasma confinement magnet module placed adjacent said passageway, said first module comprising;

a first module housing, and

a first plasma confinement magnet inside said housing.

42. The reactor of claim 41 further comprising a second removable plasma confinement magnet module placed adjacent said passageway, said second module comprising:

a second module housing, and

a second plasma confinement magnet.

43. The reactor of claim 42 wherein said first and second modules are located on opposite sides of said passageway.

44. The reactor of claim 43 wherein said first and second plasma confinement magnets have magnetic orientations which tend to oppose plasma transport or leakage through said passageway.

45. The reactor of claim 41 wherein said reactor enclosure portion comprises a semiconductor material capable of permitting power from said inductive antenna to pass through into said chamber.

46. The reactor of claim 45 further comprising an electrical potential connection to said reactor enclosure portion.

47. The reactor of claim 46 wherein said electrical potential connection connects said reactor enclosure portion to one of:

(a) RF ground, (b) a bias RF power source.

48. The reactor of claim 41 wherein said respective inductive elements are adapted to receive respective RF power signals having independently adjustable RF power levels.

49. The reactor of claim 41 wherein said respective inductive elements are solenoidal inductive elements.

50. The reactor of claim 41 further comprising:

plural concentric thermally conductive rings overlying an exterior surface of said reactor enclosure portion and in thermal contact therewith;

a heat sink plate overlying said plural concentric thermally conductive rings and in thermal contact therewith;

wherein said respective inductive elements are nested over said reactor enclosure portion in respective voids between adjacent ones of said plural concentric thermally conductive rings.

51. The reactor of claim 50 wherein said concentric thermally conductive rings comprise a semiconductor material.

52. The reactor of claim 41 wherein said reactor enclosure portion has a 3-dimensional shape.

53. The reactor of claim 52 wherein said 3-dimensional shape comprises one of:

(a) a dome, (b) a multi-radius dome, (c) a cone, (d) a truncated dome.

54. The reactor of claim 41 wherein said first module housing comprises a relatively non-magnetic thermal conductor.

55. The reactor of claim 54 wherein said first module comprises aluminum.

56. The reactor of claim 54 wherein said chamber comprises a chamber body, and wherein said first module housing is in thermal contact with said chamber body.

57. The reactor of claim 56 further comprising a cooling apparatus thermally coupled to said first module housing via said chamber body, whereby to maintain the first plasma confinement magnet below its Curie temperature.

58. The reactor of claim 41 wherein said plasma reactor chamber further comprises a pumping annulus adjacent of a periphery of said chamber, and wherein said passageway comprises a passageway communicating between said chamber and said pumping annulus.

59. The reactor of claim 41 wherein said passageway comprises a wafer slit valve.

60. The reactor of claim 41 wherein said passageway comprises a gas feed inlet.

61. The reactor of claim 60 wherein said gas feed inlet comprises a center gas feed through a ceiling of said chamber.

62. The reactor of claim 41 wherein said plasma reactor chamber further comprises a chamber side wall and said reactor enclosure portion comprises a chamber ceiling, and wherein said first module housing rests upon said chamber side wall and said ceiling rests upon said first module housing.

63. The reactor of claim 54 wherein said first module housing comprises an opening, said first magnet located inside said opening, said first module housing further comprising:

a bonding layer attaching said first magnet to an interior surface inside said opening, and

a cover plate covering said opening so as to seal said first magnet inside said first module housing.

64. The reactor of claim 63 further comprising a welding bond between said cover plate and said first module housing.

65. The reactor of claim 64 wherein said welding bond is produced by one of:

(a) E-beam welding, (b) laser welding.

66. A plasma reactor comprising:

a plasma reactor chamber and a workpiece support for holding a workpiece adjacent a support plane inside said chamber during processing, said chamber having a reactor enclosure portion facing said workpiece;

an inductive antenna adjacent and on an exterior side of said reactor enclosure portion and having more than two respective inductive elements, said respective inductive elements being at respective radial locations, said antenna being adapted to couple power into said chamber;

plural thermally conductive cooling rings resting on said exterior side of said reactor enclosure portion;

a cold plate overlying said plural cooling rings; and

an elastically deformable thermally conductive layer between each one of said plural cooling rings and said cold plate.

67. The reactor of claim 66 wherein said elastically deformable thermally conductive layer comprises Grafoil.

68. The reactor of claim 66 further comprising an RF reflector coating between said elastically deformable thermally conductive layer and each cooling ring.

69. The reactor of claim 68 wherein said RF reflector coating is thermally conductive.

70. The reactor of claim 69 wherein said RF reflector coating is electrically conductive.

71. The reactor of claim 70 wherein said RF reflector coating comprises aluminum.

72. The reactor of claim 68 wherein said reflector coating reflects RF power to prevent its absorption by said elastically deformable thermally conductive layer.

73. The reactor of claim 66 wherein said reactor enclosure portion comprises a semiconductor material capable of permitting power from said inductive antenna to pass through into said chamber.

74. The reactor of claim 73 further comprising an electrical potential connection to said reactor enclosure portion.

75. The reactor of claim 74 wherein said electrical potential connection connects said reactor enclosure portion to one of:

(a) RF ground, (b) a bias RF power source.

76. The reactor of claim 66 wherein said respective inductive elements are adapted to receive respective RF power signals having independently adjustable RF power levels.

77. The reactor of claim 66 wherein said respective inductive elements are solenoidal inductive elements.

78. The reactor of claim 66 wherein said plural thermally conductive cooling rings are concentric and said respective inductive elements are nested over said enclosure portion in respective voids between adjacent ones of said concentric cooling rings.

79. The reactor of claim 78 wherein said cooling rings comprise a semiconductor material.

80. The reactor of claim 66 wherein said reactor enclosure portion has a 3-dimensional shape.

81. The reactor of claim 80 wherein said 3-dimensional shape comprises one of:

(a) a dome, (b) a multi-radius dome, (c) a cone, (d) a truncated dome.

82. The reactor of claim 66 further comprising:

a passageway communicating with said chamber;

a first removable plasma confinement magnet module placed adjacent said passageway, said first module comprising;

a first module housing, and

a first plasma confinement magnet inside said housing.

83. The reactor of claim 82 further comprising a second removable plasma confinement magnet module placed adjacent said passageway, said second module comprising:

a second module housing, and

a second plasma confinement magnet.

84. The reactor of claim 83 wherein said first and second modules are located on opposite sides of said passageway.

85. The reactor of claim 84 wherein said first and second plasma confinement magnets have magnetic orientations which tend to oppose plasma transport or leakage through said passageway.

86. The reactor of claim 66 wherein each of said respective inductive elements comprises:

plural stacked coil windings, each of said coil windings residing generally in a respective one of plural parallel planes, the windings in adjacent planes being connected at a step region common to all said planes wherein each winding transitions from one plane to a next plane, said antenna further comprising a conductor coupled to a bottom-most one of said windings extending upwardly from one azimuthal end of said step region to a second azimuthal end of said step region toward the plane of a top-most one of said windings.

87. The reactor of claim 86 wherein said upwardly extending conductor follows an upwardly curving arcuate path.

88. The reactor of claim 66 wherein each of said respective inductive elements comprises:

stacked coil windings, each of said coil windings residing generally in a respective one of plural parallel planes, the windings in adjacent planes being connected at a step region common to all said planes wherein each winding transitions from one plane to the next plane, said coil windings being formed of a single conductor having a pair of connection sections, a first one of said connection sections extending from a top-most one of said windings and a second one of said connection sections extending from a bottom-most one of said windings, said first one of said connection sections extending upwardly away from said top-most winding, said second one of said connection sections following an arcuate path upwardly from said bottom-most winding to said top-most winding so as to provide an effective number of stacked windings which is generally uniform along said step region.

89. The plasma reactor of claim 88 wherein said arcuate path is such that said second one of connection sections is generally parallel to said parallel planes adjacent said bottom-most winding and is generally perpendicular to said parallel planes adjacent said top-most winding.

90. The reactor of claim 82 wherein said first module housing comprises a relatively non-magnetic thermal conductor.

91. The reactor of claim 90 wherein said first module comprises aluminum.

92. The reactor of claim 90 wherein said plasma chamber reactor comprises a chamber body, and wherein said first module housing is in thermal contact with said chamber body.

93. The reactor of claim 92 further comprising cooling apparatus thermally coupled to said chamber body, whereby to maintain said first plasma confinement magnet below its Curie temperature.

94. The reactor of claim 82 wherein said reactor further comprises a pumping annulus adjacent of a periphery of said chamber, and wherein said passageway comprises a passageway communicating between said chamber and said pumping annulus.

95. The reactor of claim 82 wherein said passageway comprises a wafer slit valve.

96. The reactor of claim 82 wherein said passageway comprises a gas feed inlet.

97. The reactor of claim 96 wherein said gas feed inlet comprises a center gas feed through a ceiling of said chamber.

98. The reactor of claim 82 wherein said plasma reactor chamber further comprises a chamber side wall and said reactor enclosure portion comprises a chamber ceiling, and wherein said first module housing rests upon said side wall and said ceiling rests upon said first module housing.

99. The reactor of claim 90 wherein said first module housing comprises an opening, said first magnet located inside said opening, said first module housing further comprising:

a bonding layer attaching said first magnet to an interior surface inside said opening, and

a cover plate covering said opening so as to seal said first magnet inside said first module housing.

100. The reactor of claim 99 further comprising a welding bond between said cover plate and said first module housing.

101. The reactor of claim 100 wherein said welding bond is produced by one of (a) E-beam welding, (b) laser welding.