Apparatus for and method of surface treatment for microelectronic devices

• US 5,284,544 A
• Filed: 10/17/1990
• Issued: 02/08/1994
• Est. Priority Date: 02/23/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yunogami, Takashi, Mizutani, Tatsumi
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): GOUDREAU, GEORGE A
• Application Number:
  US07/599,018
• Time in Patent Office: 1,210 Days
• Field of Search: 156/345, 156/643, 427/39, 204/298.34, 204/298.36, 204/298.04, 118/723
• US Class Current: 156/345.38
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream

Abstract

An apparatus for surface treatment according to the present invention used for carrying out dry etching, thin film deposition and so forth is provided with a neutral beam etching apparatus in order to improve etching rate. In an embodiment, microwave wave-guides forming a duplex tube, a discharge tube, a pair of solenoids arranged coaxially, a multiaperture electrode for extracting an ion beam, gas supply pipes, a set of charged particle retarding grids, a device for controlling temperature of a specimen and a vacuum unit are provided.

Claims

1. An apparatus for surface treatment, comprising:

wave-guides having a duplex structure portion;

a first plasma generating region and ion beam generating means for generating an ion beam near one end of an internal wave-guide of said wave-guides; and

a second plasma generating region for forming radicals near one end of an external wave-guide of said wave-guides.

2. An apparatus for surface treatment according to claim 1, further comprising means for controlling the temperature of a specimen at a predetermined value.

3. An apparatus for treating a surface of an object, said apparatus comprising:

first means for generating an ion beam within a vessel containing an ion beam source gas at a pressure below atmospheric pressure;

second means for introducing a reactive gas into said vessel and converting the reactive gas into a plasma to produce radicals;

said first means causing the ion beam to pass through a gas atmosphere containing the ion beam source gas and the reactive gas within said vessel to neutralize part of the charged particles in the ion beam and convert the ion beam into a mixed beam containing the ion beam and a neutral beam; and

third means for radiating substantially only the neutral beam onto an object, with charged particles in the mixed beam being substantially prevented from impinging on the object, and for supplying, among the radicals, substantially only neutral radicals to the surface of the object.

4. An apparatus according to claim 3, wherein said first means includes plasma generating means and an ion beam extracting electrode unit.

5. An apparatus according to claim 3, wherein said vessel includes means for supplying microwave electric power to the vessel interior.

6. An apparatus according to claim 3, wherein said vessel includes means for supplying high frequency electric power to the vessel interior.

7. An apparatus according to claim 3, wherein said third means includes first, second, third and fourth plate-like grids arranged substantially in parallel with each other, with a predetermined spacing between adjacent ones of said grids, and with said first and fourth grids respectively being nearest to and farthest from said second means;

means for applying ground potential to said first grid;

means for applying a negative voltage to said second grid;

means for applying a positive voltage to said third grid; and

means for applying the ground potential to said fourth grid.

8. An apparatus according to claim 3, wherein said third means includes first and second comb-like deflecting units arrange din a nested structure;

means for supplying a positive voltage to said first deflecting unit; and

means for supplying a negative voltage to said second deflecting unit.

9. An apparatus according to claim 3, wherein said second means is spaced from the surface of the object by not more than 10 cm.

10. An apparatus according to claim 3, further comprising means for holding the object so that the incident angle of the neutral beam onto the surface of the object is not parallel with the normal to the surface of said object;

and means for precession rotating of said holding means.

11. An apparatus according to claim 3, wherein the object is a semiconductor device.

12. An apparatus according to claim 3, wherein said second means includes plasma generating means.

13. An apparatus according to claim 12, wherein said plasma generating means includes a plurality of plasma generators.

14. An apparatus according to claim 12, wherein said plasma generating means is annular plasma generating means on a wall surface of said vessel.

15. An apparatus according to claim 3, wherein said vessel includes waveguide means having a duplex structure portion, and wherein at least a portion of said first means is arranged near one end of an internal waveguide of said duplex structure portion and at least a portion of said second means is arranged near one end of an external waveguide of said duplex structure portion.

16. An apparatus according to claim 15, wherein said first means includes plasma generating means and an ion beam extracting electrode unit.

17. An apparatus according to claim 15, wherein said second means includes plasma generating means.

18. An apparatus according to claim 3, wherein said third means includes a first grid;

a second grid further from said second means than said first grid is from said second means;

means for supplying a negative voltage to said first grid; and

means for supplying a positive voltage to said second grid.

19. An apparatus according to claim 18, wherein said first and second grids are made of carbon fibers.

20. An apparatus according to claim 18, wherein said first and second grids are substantially parallel with each other.

21. An apparatus according to claim 20, wherein said first and second grids are formed in a double layer structure of carbon and silicon.

22. An apparatus according to claim 20, wherein said first and second grids are formed in a double layer structure of silicon carbide and silicon.

23. An apparatus for treating a surface of an object, said apparatus comprising an enclosed vessel having an interior pressure below atmospheric pressure, and a discharge tube assembly within said vessel, said discharge tube assembly including means defining a first discharge space and a second discharge space, said defining means including a wall surface and means for supplying high frequency electric power or microwave electric power to the first discharge space and the second discharge space;

means for independently controlling the amount of high frequency electric power or microwave electric power supplied to said first discharge space and to said second discharge space, said first discharge space being arranged to extract an ion beam from which a neutral beam to be radiated onto the object is produced, and said second discharge space being arranged to produce radicals for treating the surface of the object.

24. An apparatus according to claim 23, wherein said second means includes first, second, third and fourth plate-like grids arranged substantially in parallel with each other, with a predetermined spacing between adjacent ones of said grids, with said first and fourth grids, respectively, being nearest to and farthest from said second plasma discharge space;

means for applying ground potential to said first grid;

means for applying a negative voltage to said second grid;

means for applying a positive voltage to said third grid; and

means for applying the ground potential to said fourth grid.

25. An apparatus according to claim 23, wherein said second means includes first and second comb-like deflecting units arranged in a nested structure;

means for supplying a positive voltage to said first deflecting unit; and

means for supplying a negative voltage to said second deflecting unit.

26. An apparatus according to claim 23, wherein said second discharge space is spaced from the surface of the object by not more than 10 cm.

27. An apparatus according to claim 23, further comprising means for holding the object so that the incident angle of the neutral beam onto the surface of the object is not parallel with a normal to the surface of the object;

and means for precession rotating said holding means.

28. An apparatus according to claim 23, wherein the object is a semiconductor device.

29. An apparatus according to claim 23, further comprising:

first means for passing the ion beam through a gas within said vessel to neutralize part of the charged particles of the ion beam and convert the ion beam into a mixed beam of an ion beam and a neutral beam; and

second means for radiating the neutral beam onto the object, with charged particles in the mixed beam being substantially prevented from impinging on the object, and for supplying, among the radicals, substantially only neutral radicals to the surface of the object.

30. An apparatus according to claim 29, wherein said first and second grids are substantially parallel with each other.

31. An apparatus according to claim 29, wherein said second means includes a first grid;

a second grid further from said second discharge space than said first grid is from said discharge space;

means for supplying a negative voltage to said first grid; and

means for supplying a positive voltage to said second grid.

32. An apparatus according to claim 31, wherein said first and second grids are formed in a double layer structure of carbon and silicon.

33. An apparatus according to claim 31, wherein said first and second grids are formed in a double layer structure of silicon carbide and silicon.

34. An apparatus according to claim 31, wherein said first and second grids are made of carbon fibers.

35. An apparatus for treating a surface of an object in a vessel at a pressure below atmospheric pressure, said apparatus comprising:

waveguide means within the vessel and having a duplex structure portion;

first plasma generating means for producing an ion beam;

ion beam extracting means;

means arranging said first plasma generating means and said ion beam extracting means near one end of an internal waveguide of said duplex structure portion;

second plasma generating means for producing radicals;

means arranging said second plasma generating means near one end of an external waveguide of said duplex structure portion;

means for passing the ion beam through a gas within the vessel to neutralize part of the charged particles of the ion beam and convert the ion beam to a mixed beam of an ion beam and a neutral beam; and

means for radiating the neutral beam onto an object, with charged particles in the mixed beam being substantially prevented from impinging on the object, and for supplying, among the radicals, substantially only neutral radicals to the surface of the object.

36. An apparatus according to claim 35, wherein said second means includes first, second, third and fourth plate-like grids arranged substantially in parallel with each other, with a predetermined spacing between adjacent ones of said grids, and with said first and fourth grids, respectively, being nearest to and farthest from said second plasma generating means;

means for applying ground potential to said first grid;

means for applying a negative voltage to said second grid;

means for applying a positive voltage to said third grid; and

means for applying the ground potential to said fourth grid.

37. An apparatus according to claim 35, wherein said second means includes first and second comb-like deflecting units arranged in a nested structure;

means for supplying a positive voltage to said first deflecting unit; and

means for supplying a negative voltage to said second deflecting unit.

38. An apparatus according to claim 35, further comprising means for holding the object so that the incident angle of the neutral beam onto the surface of the object is not parallel with a normal to the surface of the object;

and means for precession rotating said holding means.

39. An apparatus according to claim 35, wherein the object is a semiconductor device.

40. An apparatus according to claim 35, wherein said second means includes a first grid;

a second grid further from said second plasma generating means than said first grid is from said second plasma generating means;

means for supplying a negative voltage to said first grid; and

means for supplying a positive voltage to said second grid.

41. An apparatus according to claim 40, wherein said first and second grids are substantially parallel with each other.

42. An apparatus according to claim 40, wherein said first and second grids are formed in a double layer structure of carbon and silicon.

43. An apparatus according to claim 40, wherein said first and second grids are formed in a double layer structure of silicon carbide and silicon.

44. An apparatus according to claim 40, wherein said first and second grids are made of carbon fibers.

45. A method of surface treatment of a specimen, comprising generating a neutral beam within a vacuum chamber;

generating radicals, including neutral radicals by forming particles in said vacuum chamber into plasma within said vacuum chamber;

holding a specimen so that the specimen surface is oriented in a direction not normal to the direction of the neutral beam;

rotating the specimen; and

supplying the neutral beam and neutral radicals to the specimen surface.

46. A method of surface treatment according to claim 45, wherein said neutral beam is generated by operating charge exchange reactions with gas molecules on the ion beam which has been extracted from plasma.

47. A method of surface treatment according to claim 45, wherein said plasma is generated in a space within 10 cm of the specimen surface.

48. A method of surface treatment according to one of claims 45 to 47, further comprising maintaining the specimen temperature constant during the surface treatment.

49. A method of surface treatment according to one of claims 45 to 47, wherein a plurality of grids are arranged just in front of the specimen, and voltages are applied to the grids to prevent charged particles from being incident on the specimen surface.

50. A method of surface treatment according to one of claims 45 to 47, wherein rare gas atoms are contained in the particles of said neutral beam.

51. A method of surface treatment according to one of claims 45 to 47, wherein neutral radicals supplied to the specimen surface are generated from a gas containing carbon, fluorine and hydrogen as constituents, and a specimen composed of a material having SiO₂ as a principal component is etched.

52. A method of surface treatment according to claim 48, wherein the specimen temperature is held at -100 C or below.

53. A method of surface treatment according to one of claims 45 to 47, wherein the energy of said neutral beam is at 500 eV or below.