High density plasma process chamber

• US 6,095,084 A
• Filed: 07/14/1997
• Issued: 08/01/2000
• Est. Priority Date: 02/02/1996
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Grimard, Dennis S., Collins, Kenneth S., Kumar, Ananda H., Kholodenko, Arnold, Chafin, Michael G., Mohn, Jonathan D., Shamouilian, Shamouil
• Primary Examiner(s): Dang, Thi
• Assistant Examiner(s): Zervigon, Rudy
• Application Number:
  US08/893,599
• Time in Patent Office: 1,114 Days
• Field of Search: 156/345, 156/662.1, 156/643.1, 361/234, 204/298.37, 118/723 E, 489/678, 315/111.41, 438/656
• US Class Current: 118/723.00E
• CPC Class Codes: C23C 16/00 Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes reactive sputtering or vacuum evaporation C23C14/00
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• 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 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32174 Circuits specially adapted for controlling the RF discharge
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32532 Electrodes
• CPC Class Codes: H01J 37/32559 Protection means, e.g. coatings

Abstract

A process chamber 55 for processing a semiconductor substrate 60 in a plasma, comprises a process gas distributor 100 for distributing process gas into a plasma zone 65 in the chamber. An inductor antenna 135 is used to form an inductive plasma from the process gas in the plasma zone. A primary bias electrode 145 on a ceiling 140 of the chamber 55 has a conducting surface 150 exposed to the plasma zone 65. A dielectric member 155 comprising a power electrode 165 embedded therein, has a receiving surface for receiving a substrate 60. A secondary bias electrode 170 below the dielectric member 155 has a conducting surface 175 exposed to the plasma zone 65. An electrode voltage supply 180 maintains the power electrode 165, primary bias electrode 145, and secondary bias electrode 170, at different electrical potentials to provide a high density, highly directional, plasma in the plasma zone 65 of the chamber 55.

Claims

1. A process chamber capable of processing a substrate in a plasma, the process chamber comprising:

(a) a process gas distributor capable of distributing process gas into a plasma zone of the process chamber;

(b) a primary electrode;

(c) a dielectric member having a power electrode therein, the dielectric member having a receiving surface capable of receiving the substrate;

(d) a secondary electrode below the dielectric member; and

(e) an electrode voltage supply adapted to maintain the power electrode, primary electrode, and secondary electrode, at one or more electrical potentials so as to capacitively couple the primary electrode and the power electrode to energize the process gas.

2. The process chamber of claim 1 wherein the electrode voltage supply is adapted to maintain the power electrode at an electrical potential different than the electrical potentials of the primary and secondary electrodes.

3. The process chamber of claim 1 wherein the electrode voltage supply is adapted to maintain the power electrode at a first electrical potential, the primary electrode at a second electrical potential, and the secondary electrode at a third electrical potential.

4. The process chamber of claim 1 wherein the electrode voltage supply is adapted to maintain the power electrode and the primary electrode at electrical potentials that differ by at least about 1000 volts.

5. The process chamber of claim 1 absent an insulator shield surrounding the dielectric member.

6. The process chamber of claim 1 wherein the dielectric member comprises a cover layer capable of allowing coupling of an RF voltage applied to the power electrode through the cover layer and to the primary electrode, and a support layer capable of reducing coupling of the RF voltage applied to the power electrode through the support layer to the secondary electrode.

7. The process chamber of claim 6 wherein the cover layer comprises an RF reactance of about 1 to about 500 Ohms, and the support layer comprises an RF reactance of about 100 to about 10000 Ohms.

8. The process chamber of claim 6 wherein the cover layer comprises a dielectric constant of at least about 2 and a thickness of about 1 to about 1000 microns;

and the support layer comprise a dielectric constant of at least about 1 and a thickness of about 0.1 to about 15 mm.

9. The process chamber of claim 6 wherein the power electrode comprises a perimeter edge facing an electrically grounded sidewall of the process chamber, and wherein the dielectric member comprises a non-coupling side layer that covers the perimeter edge.

10. The process chamber of claim 1 wherein the ratio of the surface area of the primary electrode to the surface area of the power electrode is at least about 0.9:

1.

11. The process chamber of claim 1 wherein the secondary electrode comprises a conductor element having a surface exposed to the plasma and absent an insulator shield.

12. The process chamber of claim 11 wherein the secondary electrode comprises channels adapted to circulate heat transfer fluid therethrough, and wherein the voltage supply is adapted to maintain the secondary electrode at a floating electrical potential.

13. The process chamber of claim 1 wherein the dielectric member comprises a monolith made from one or more of aluminum oxide, aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, and zirconium oxide.

14. The process chamber of claim 1 further comprising an inductor antenna adjacent to the process chamber.

15. The process chamber of claim 14 wherein the inductor antenna is adjacent to the ceiling of the process chamber and wherein the ceiling is capable of allowing an inductive field to permeate therethrough.

16. The process chamber of claim 15 wherein the primary electrode is formed on the ceiling of the process chamber.

17. The process chamber of claim 15 wherein the inductor antenna comprises inner and outer antennas.

18. A method of using the process chamber of claim 14 to process a substrate, the method comprising the steps of:

(a) placing a substrate on the receiving surface of the unitary dielectric member;

(b) passing a current through the inductor antenna to generate an inductive field in the chamber; and

(c) maintaining the power electrode, primary bias electrode, and secondary bias electrode at different electrical potentials thereby maintaining a high density, highly directional plasma in the chamber.

19. A method according to claim 18 comprising the steps of applying RF and DC voltages to the power electrode embedded in the unitary monolithic dielectric member, and electrically grounding the primary and secondary bias electrodes.

81. The process chamber of claim 1 wherein the power electrode is embedded in the dielectric member.

20. A process chamber capable of processing a substrate in a plasma, the process chamber comprising:

(a) a process gas distributor capable of distributing process gas into a plasma zone in the chamber;

(b) a primary electrode;

(c) a dielectric member comprising a power electrode therein, the dielectric member comprising (i) a coupling layer having a receiving surface for receiving a substrate in facing relationship to the primary electrode, the coupling layer comprising an electric field absorption sufficiently low for the power electrode to capacitively couple with the primary electrode to energize process gas in the chamber and to electrostatically hold the substrate, and (ii) a non-coupling layer surrounding the other surfaces of the power electrode, the non-coupling layer comprising an electric field absorption sufficiently high to substantially preclude capacitive coupling of the power electrode to surrounding walls of the chamber;

(d) a secondary electrode below the non-coupling layer; and

(e) an electrode voltage supply adapted to provide an RF voltage and a DC voltage to the power electrode in the dielectric member.

21. The process chamber of claim 20 wherein the chamber comprises an impedance load of less than about 3000 picofarads.

22. The process chamber of claim 20 wherein the coupling layer comprises an RF reactance of about 1 to about 500 Ohms, and the non-coupling layer comprises an RF reactance of about 100 to about 10000 Ohms.

23. The process chamber of claim 20 wherein the coupling layer comprises a dielectric constant of at least about 2 and a thickness of from about 1 to about 1000 microns;

and the non-coupling layer comprises a dielectric constant of at least about 1 and a thickness of about 0.1 to about 15 mm.

24. The process chamber of claim 20 further comprising an inductor antenna for providing an induction field in the plasma zone.

25. The process chamber of claim 20 wherein the ratio of the surface area of the primary electrode to the surface area of the power electrode is at least about 0.9:

1.

26. The process chamber of claim 20 wherein the dielectric member is supported by the secondary electrode, the secondary electrode comprising a conductor element having surfaces adapted to be exposed directly to the plasma, and having channels for circulating heat transfer fluid therethrough.

82. The process chamber of claim 20 wherein the power electrode is embedded in the dielectric member.

27. A process chamber capable of processing a substrate in a plasma, the process chamber comprising:

(a) a gas distribution system for distributing process gas into the chamber;

(b) a primary electrode capable of allowing an RF induction field to permeate therethrough;

(c) an inductor antenna to generate the RF induction field; and

(d) a dielectric member comprising a power electrode therein, the dielectric member having a coupling layer that has a receiving surface for receiving a substrate and comprises an electric field absorption sufficiently low for RF and DC voltages applied to the power electrode to capacitively couple therethrough to energize process gas in the chamber and to electrostatically hold the substrate, respectively, and an non-coupling layer surrounding the other surfaces of the electrode, the non-coupling layer comprising an electric field absorption sufficiently high to reduce capacitive coupling therethrough;

(e) a secondary electrode below the non-coupling layer; and

(f) an electrode voltage supply adapted to maintain the primary electrode and power electrode at different electrical potentials relative to one another thereby energizing the process gas.

28. The process chamber of claim 27 wherein the process chamber is absent any insulator shield surrounding the unitary monolithic dielectric member.

29. The process chamber of claim 27 wherein the coupling layer comprises an RF reactance of about 1 to about 500 Ohms, and the non-coupling layer comprise an RF reactance of about 100 to about 10000 Ohms.

30. The process chamber of claim 27 wherein the cover layer comprises a dielectric constant of at least about 2 and a thickness of about 1 to about 1000 microns;

and the non-coupling layer comprises a dielectric constant of at least about 1 and a thickness of about 0.1 to about 15 mm.

31. The process chamber of claim 27 wherein the ratio of the surface area of the primary electrode to that of the power electrode is at least about 0.9:

1.

32. The process chamber of claim 27 wherein the dielectric member is supported by the secondary electrode, the secondary electrode comprising a conductor element having surfaces adapted to be exposed directly to the plasma, absent a surrounding insulator shield, and comprising channels for circulating heat transfer fluid therethrough.

33. The process chamber of claim 27 wherein the secondary electrode comprises a secondary electrode below the dielectric member, and wherein the electrode voltage supply (i) maintains the power electrode and the primary electrode at electrical potentials differing by at least about 1000 volts to energize the plasma in the chamber, and (ii) maintains the power electrode and the secondary electrode at electrical potentials differing by at least about 100 volts to reduce stray capacitances in the chamber, thereby providing a plasma having plasma ions that are energized in a direction substantially perpendicular to the surface of the substrate.

34. A method of using the process chamber of claim 27 to process a substrate, the method comprising the steps of:

(a) placing a substrate on the surface of the unitary dielectric member;

(b) passing an RF current through the inductor antenna to generate an RF induction field in the chamber; and

(c) maintaining the primary and power electrodes in the chamber at different electrical potentials to form a high density, highly directional plasma in the chamber.

83. The process chamber of claim 27 wherein the power electrode is embedded in the dielectric member.

35. A process chamber capable of processing a substrate in a plasma, the process chamber comprising:

(a) a process gas distributor capable of distributing process gas into a plasma zone in the process chamber;

(b) an inductor antenna capable of forming a plasma from the process gas in the plasma zone, and a conducting surface adapted to be exposed to the plasma zone;

(c) a dielectric member below the conducting surface, the dielectric member comprising a receiving surface capable of receiving a substrate thereon, and the dielectric member comprising an electrode; and

(d) an electrode voltage supply adapted to maintain the conducting surface and the electrode at different electrical potentials to capacitively couple the conducting surface and the electrode and thereby energize the process gas,

wherein the dielectric member comprises a cover layer that has an RF reactance of about 1 to about 500 Ohms, and a surrounding layer having an RF reactance of about 100 to about 10000 Ohms.

36. The process chamber of claim 35 wherein the electrode voltage supply is adapted to maintain the conducting surface and the electrode at electrical potentials that differ by at least about 1000 volts.

37. The process chamber of claim 35 absent an insulator shield surrounding the dielectric member.

38. The process chamber of claim 35 wherein the cover layer comprises a dielectric constant of at least about 2 and a thickness of from about 1 to about 1000 microns;

and the surrounding layer comprises a dielectric constant of at least about 1 and a thickness of about 0.1 to about 15 mm.

39. The process chamber of claim 35 wherein the ratio of the surface area of the ceiling to the surface area of the electrode is at least about 0.9:

1.

40. The process chamber of claim 39 wherein the dielectric member is supported by a conductor element having surfaces adapted to be exposed directly to the plasma.

41. The process chamber of claim 35 further comprising a plurality of dielectric members.

42. A process chamber capable of processing a substrate in a plasma, the process chamber comprising:

(a) a gas distribution system for distributing process gas into the chamber;

(b) a primary electrode;

(c) a dielectric member comprising a power electrode therein, the dielectric member having a coupling layer that forms a receiving surface adapted to receive a substrate, the coupling layer having an electric field absorption sufficiently low for RF and DC voltages applied to the electrode to capacitive couple therethrough to energize the plasma and to electrostatically hold the substrate, respectively, and a non-coupling layer comprising an electric field absorption sufficiently high to reduce capacitive coupling therethrough;

(d) an electrode voltage supply adapted to maintain the primary electrode and power electrode at different electrical potentials relative to one another; and

(e) a multi-directional magnetic field generator adjacent to the chamber and adapted to generate in the plasma zone a multi-directional magnetic field having an angular orientation and magnitude that varies over time,

wherein the coupling layer comprises an RF reactance of about 1 to about 500 Ohms, and the non-coupling layer comprises an RF reactance of about 100 to about 10000 Ohms.

43. The process chamber of claim 42 wherein the multi-directional magnetic field generator is adapted to generate a multi-directional magnetic field that moves in a circular direction.

44. The process chamber of claim 42 wherein the multi-directional magnetic field generator comprises:

(1) a plurality of electromagnets positioned adjacent to a sidewall of the chamber; and

(2) an electromagnet power source that varies the current applied to the electromagnets to generate the multi-directional magnetic field in the plasma zone.

45. The process chamber of claim 44 wherein the electromagnets comprise a plurality of paired electrically conducting coils, each pair of coils generating a magnetic field substantially planar to the plane of the substrate, and wherein the power source energizes the paired coils in a selected sequence for electrically generating a magnetic field and selectively moving the magnetic field by independently varying the angular orientation and magnitude of the magnetic field generated by each coil pair.

46. The process chamber of claim 42 wherein the multi-directional magnetic field generator comprises:

(1) a plurality of movable permanent magnets positioned adjacent to the chamber; and

(2) means for moving the permanent magnets to generate the multi-directional magnetic field in the plasma zone.

47. The process chamber of claim 42 wherein the process chamber is absent any insulator shield surrounding the unitary monolithic dielectric member.

48. The process chamber of claim 42 wherein the cover layer comprises a dielectric constant of at least about 2 and a thickness of from about 1 to about 1000 microns;

and the non-coupling layer comprises a dielectric constant of at least about 1 and a thickness of about 0.1 to about 15 mm.

49. A process chamber capable of processing a substrate in a plasma, the process chamber comprising:

(a) a process gas distributor capable of distributing process gas into a plasma zone in the process chamber;

(b) a primary electrode in the process chamber;

(c) a dielectric member comprising a power electrode, the dielectric member having a receiving surface capable of receiving a substrate below the primary electrode; and

(d) an electrode voltage supply adapted to maintain the power electrode and the primary electrode at different electrical potentials relative to one another to energize the process gas,

wherein the dielectric member comprises a cover layer capable of allowing coupling of an RF voltage applied to the power electrode through the cover layer and to the primary electrode, and a support layer capable of reducing coupling of the RF voltage applied to the power electrode through the support layer to the secondary electrode and wherein the cover layer comprises an RF reactance of about 1 to about 500 Ohms, and the support layer comprises an RF reactance of about 100 to about 10000 Ohms.

50. The process chamber of claim 49 wherein the electrode voltage supply is adapted to maintain the power electrode at a higher electrical potential than an electrical potential of the primary electrode.

51. The process chamber of claim 49 wherein the electrode voltage supply is adapted to maintain the power electrode at a first electrical potential and the primary electrode at a second electrical potential.

52. The process chamber of claim 49 wherein the electrode voltage supply is adapted to maintain the power electrode and the primary electrode at electrical potentials differing by at least about 1000 volts.

53. The process chamber of claim 49 absent an insulator shield surrounding the dielectric member.

54. The process chamber of claim 50 wherein the chamber is absent any insulator shield surrounding the unitary monolithic dielectric member.

55. The process chamber of claim 49 wherein the cover layer comprises a dielectric constant of at least about 2 and a thickness of about 1 to about 1000 microns;

and the support layer comprise a dielectric constant of at least about 1 and a thickness of about 0.1 to about 15 mm.

56. The process chamber of claim 49 wherein the power electrode comprises a perimeter edge facing an electrically grounded sidewall of the process chamber, and wherein the dielectric member comprises a non-coupling side layer that covers the perimeter edge of the power electrode.

57. The process chamber of claim 49 wherein the ratio of the surface area of the primary electrode to the surface area of the power electrode is at least about 0.9:

1.

58. The process chamber of claim 49 absent an insulator shield surrounding the dielectric member.

59. The process chamber of claim 49 further comprising an inductor antenna adjacent to a dome shaped dielectric ceiling of the process chamber.

60. The process chamber of claim 59 wherein the dielectric ceiling comprises one or more of aluminum oxide, aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, and zirconium oxide.

61. A process chamber capable of processing a substrate in a plasma, the process chamber comprising:

(a) a gas distribution system capable of distributing process gas into the chamber;

(b) a primary electrode;

(c) an inductor antenna capable of generating the RF induction field;

(d) a dielectric member having a power electrode therein, and a receiving surface for receiving the substrate, the power electrode adapted to capacitively couple with the primary electrode to energize the process gas, and

(e) a secondary electrode below the dielectric member.

62. The process chamber of claim 61 further comprising one or more voltage supplies for maintaining a potential across the power electrode and the primary electrode to capacitively couple the electrodes, and for providing a current to the inductor coil to generate the RF induction field in the chamber, whereby a high density, highly directional plasma is formed in the chamber.

63. The process chamber of claim 62 wherein the voltage supply provides to the power electrode an RF voltage adapted to energize the plasma in the chamber, and a DC chucking voltage adapted to electrostatically holds the substrate to the dielectric member.

64. The process chamber of claim 61 wherein the process chamber is absent any insulator shield surrounding the dielectric member.

65. The process chamber of claim 61 wherein the dielectric member comprises a unitary monolith having (i) a coupling cover layer having an RF reactance of about 1 to about 500 Ohms covering the power electrode, to allow coupling of the power electrode to the plasma;

and (ii) a non-coupling layer surrounding the other surfaces of the electrode, the non-coupling layer having an RF reactance of about 100 to about 10000 Ohms.

66. The process chamber of claim 61 wherein the ratio of the surface area of the primary electrode to that of the power electrode is at least about 0.9:

1.

67. The process chamber of claim 61 wherein the semiconductor wall comprises silicon.

68. The process chamber of claim 61 wherein the dielectric member is supported by a conductor element having surfaces adapted to be exposed directly to the plasma, that is absent a surrounding insulator shield, and which comprises channels for circulating heat transfer fluid therethrough.

69. The process chamber of claim 61 wherein the electrode voltage supply (i) maintains the power electrode and the primary electrode at electrical potential differing by at least about 1000 volts;

and (ii) maintains the power electrode and the secondary electrode at electrical potentials differing by at least about 100 volts.

70. A method of using the process chamber of claim 61 process a substrate, the method comprising the steps of:

(a) placing the substrate on the receiving surface of the dielectric member;

(b) passing an RF current through the inductor antenna to generate an RF induction field in the chamber; and

(c) maintaining the primary bias electrode and power electrode in the chamber at different electrical potentials, and applying a current to the inductor antenna, whereby a high density, highly directional plasma is formed in the chamber.

84. The process chamber of claim 61 wherein the power electrode is embedded in th e dielectric member.

86. The process chamber of claim 61 wherein the primary electrode is capable of allowing an RF induction field to permeate therethrough.

71. A process chamber for processing a substrate in a plasma, the process chamber comprising:

(a) a process gas distributor capable of distributing process gas into the chamber;

(b) a primary electrode forming a wall of the chamber, the primary electrode having a conducting surface adapted to be exposed to the plasma;

(c) a dielectric member comprising a power electrode therein, the dielectric member having a receiving surface layer to receive the substrate, the receiving surface layer covering the power electrode and having an electric field absorption sufficiently low for RF and DC voltages applied to the power electrode to capacitively couple with the primary electrode to energize the process gas and to electrostatically hold the substrate;

(d) a secondary electrode below the dielectric member; and

(e) an electrode voltage supply adapted to maintain the primary electrode and power electrode at different electrical potentials relative to one another.

72. The process chamber of claim 71 wherein the electrode voltage supply is adapted to maintain the power electrode at a different electrical potential than the secondary electrode.

85. The process chamber of claim 71 wherein the power electrode is embedded in the dielectric member.

73. A process chamber capable of processing a substrate, the process chamber comprising:

(a) gas distributor capable of distributing process gas into the process chamber;

(b) a primary electrode;

(c) a dielectric member having a power electrode therein, the dielectric member having a receiving surface capable of receiving the substrate, wherein the dielectric layer comprises a cover layer having an RF reactance of about 1 to about 500 Ohms and a support layer having an RF reactance of about 100 to about 10000 Ohms.

74. The process chamber of claim 73 wherein the cover layer is capable of allowing coupling of an RF voltage applied to the power electrode through the cover layer and to the primary electrode, and the support layer is capable of reducing coupling of the RF voltage applied to the power electrode through the support layer to the secondary electrode.

75. The process chamber of claim 73 further comprising a secondary electrode below the dielectric member.

76. The process chamber of claim 73 further comprising an electrode voltage supply adapted to maintain the power electrode and primary electrode at one or more electrical potentials so as to capacitively couple the primary electrode and the power electrode to energize the process gas to form a plasma.

77. A process chamber capable of processing a substrate, the process chamber comprising:

(a) gas distributor capable of distributing process gas into the process chamber;

(b) a primary electrode;

(c) a dielectric member having a surface adapted to receive the substrate, the dielectric member having a power electrode therein, the power electrode adapted to capacitively couple with the primary electrode to energize the process gas and adapted to electrostatically hold the substrate; and

(d) a secondary electrode below the dielectric member.

78. The process chamber of claim 77 wherein the dielectric member a cover layer capable of allowing coupling of an RF voltage applied to the power electrode through the cover layer and to the primary electrode, and a support layer capable of reducing coupling of the RF voltage applied to the power electrode through the support layer to the secondary electrode.

79. The process chamber of claim 77 wherein the dielectric member a cover layer having an RF reactance of about 1 to about 500 Ohms and a support layer having an RF reactance of about 100 to about 10000 Ohms.

80. The process chamber of claim 77 wherein the power electrode is embedded in the dielectric member.