Reactive ion beam etching method and a thin film head fabricated using the method

• US 6,238,582 B1
• Filed: 03/30/1999
• Issued: 05/29/2001
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: Veeco Instruments Incorporated
• Original Assignee: Veeco Instruments Incorporated
• Inventors: Londono, Jhon F., Hines, Danielle S., Williams, Kurt E., Druz, Boris L.
• Primary Examiner(s): POWELL, WILLIAM A
• Application Number:
  US09/281,663
• Time in Patent Office: 791 Days
• Field of Search: 216/22, 216/27, 216/66, 216/67, 438/707, 438/712
• US Class Current: 216/22
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers

Abstract

A reactive ion beam etching method which employs an oxidizing agent in a plasma contained in an ion source to control carbonaceous deposit (e.g., polymer) formation within the ion source and on the substrate. During operation of an ion source, after operating the ion source with a plasma having a carbonaceous deposit forming species, a plasma containing an oxidizing agent (species) is generated within the ion source. Preferably, within the ion source a plasma is maintained essentially continuously between the time that the carbonaceous deposit forming species is present and the time that the oxidizing agent is present. A reactive ion beam extracted from an ion source containing a plasma having an oxidizing species may be impinged onto a sample substrate to remove (i.e., etch) any carbonaceous material deposits (e.g., polymers) formed on the sample, such as may be formed from previous reactive ion beam etching (RIBE) processing steps using an ion beam having species which may form carbonaceous (e.g., polymer) deposits on the sample substrate structure. Preferably, a reactive ion beam containing an oxidizing species is incident upon the sample at an angle which enhances the selectivity of the carbonaceous deposit (e.g., polymer) etching relative to other materials upon which the ion beam impinges. A thin film magnetic head is fabricated according to a pole trimming process which employs RIBE with an oxidizing species to remove any carbonaceous material (e.g., polymer) deposits formed during a previous fluorocarbon based RIBE step.

Claims

1. A process for fabricating a thin film magnetic head, comprising the steps of:

forming a structure comprising a lower magnetic pole layer, a gap layer overlying the lower magnetic pole layer, and an patterned upper magnetic pole layer over the gap layer;

bombarding said structure with a first ion beam extracted from a first ion source, the first ion beam operative in etching the gap layer and including a species that is capable of forming a carbonaceous deposit on at least a portion of said structure; and

bombarding said structure with a second ion beam that includes an oxidizing species to substantially remove the carbonaceous deposit that may have been formed from the first ion beam being directed at said structure.

2. The process according to claim 1, wherein said patterned upper magnetic pole layer acts as a mask during etching of said gap layer by said first ion beam.

3. The process according to claim 1, wherein a patterned photoresist layer overlying said patterned upper magnetic pole layer acts as a mask during etching of said gap layer by said first ion beam.

4. The process according to claim 1, further comprising the step of, prior to etching the gap layer with said first ion beam, etching a seed layer overlying said gap layer and underlying said upper patterned magnetic layer.

5. The process according to claim 1, wherein said step of etching the gap layer with said first ion beam etches a fraction of the initial thickness of said gap layer, and further comprising the step, after said step of bombarding said structure with the second ion beam, of repeating said steps of etching the gap layer followed by bombarding said structure with the second ion beam at least until the entire thickness of the gap layer is etched.

6. The process according to claim 1, wherein said step of etching the gap layer with said first ion beam etches the entire thickness of said gap layer before bombarding said structure with the second ion beam.

7. The process according to claim 1, further comprising the step of, after etching substantially the entire thickness of the gap layer to provide a patterned gap layer, bombarding said structure with an inert ion beam to etch a portion of said lower magnetic pole layer.

8. The process according to claim 7, wherein said step of etching the lower magnetic pole layer with an inert ion beam is performed to etch a desired total thickness of said lower magnetic pole layer by repeating the steps of (a) bombarding said structure with a first inert ion beam directed at a low angle of incidence to the structure to etch a fraction of a desired total thickness of said lower magnetic pole layer, and (b) bombarding said structure with a second inert ion beam directed at a high angle of incidence to the structure to remove redeposition from sidewall structures.

9. The process according to claim 8, wherein said first inert and second inert ion beams are generated using a single ion source.

10. The process according to claim 8, wherein said first inert and second inert ion beams are generated with separate ion sources.

11. The process according to claim 10, wherein said first inert and second inert ion beams impinge on said structure during an overlapping time period.

12. The process according to claim 1, wherein said second ion beam is generated using said first ion source.

13. The process according to claim 12, wherein the first ion beam is generated using a first plasma produced using a fluorocarbon precursor gas, and said second ion beam is generated using a second plasma produced by introducing an oxidizing gas into the first plasma while the fluorocarbon precursor gas is eliminated.

14. The process according to claim 13, wherein the first plasma is produced using the fluorocarbon precursor gas mixed with an inert precursor gas.

15. The process according to claim 13, wherein the first plasma is produced using the fluorocarbon precursor gas exclusive of other precursor gases.

16. The process according to claim 12, wherein the first ion beam is generated using a first plasma produced using a fluorocarbon precursor gas mixed with an an inert precursor gas, and said second ion beam is generated using a second plasma produced by introducing an oxidizing gas into an extant plasma that comprises species derived from the inert precursor gas and is substantially devoid of species derived from the fluorohydrocarbon precursor gas.

17. The method according to claim 16, further comprising the step of maintaining a plasma having oxidizing species derived from the oxidizing gas within the first ion source after the second ion beam etching step is terminated.

18. The process according to claim 1, wherein said second ion beam is generated using a second ion source that is independent of the first ion source.

19. The process according to claim 18, wherein said first and second ion beams impinge on said structure during an overlapping time period.

20. The method according to claim 18, further comprising the step of generating a plasma from an oxidizing precursor gas within the first ion source after terminating said first ion beam.

21. The process according to claim 1, wherein said first ion beam is directed at a first angle of incidence relative to a normal to the structure surface, and wherein said second ion beam is directed at a second angle of incidence relative to the sample normal, said second angle of incidence not equal to said first angle of incidence.

22. The method according to claim 21, wherein said first angle of incidence is less than about 45 degrees relative to the sample normal, and wherein said second angle of incidence is greater than about 60 degrees relative to the sample normal.

23. The method according to claim 1, wherein said first ion beam is directed at a first angle of incidence relative to a normal to the structure surface, said first angle selected to enhance the selectivity of etching the gap layer relative to the patterned upper magnetic pole layer.

24. The method according to claim 1, wherein said second ion beam is directed at a second angle of incidence relative to the sample normal, said second angle selected to enhance the selectivity of removing the carbonaceous deposits relative to etching the gap layer.

25. The process according to claim 1, wherein said upper and lower magnetic pole layers each comprise permalloy and said gap layer comprises alumina.

26. The process according to claim 25, wherein the first ion beam is generated using a fluorocarbon.

27. The process according to claim 26, wherein the rate said first ion beam in etching the alumina is at least about fifteen times greater than the rate of etching the permalloy.

28. The process according to claim 27, wherein the fluorocarbon is CHF3.

29. The process according to claim 28, wherein the rate of etching the permalloy is negligible compared to the rate of etching the alumina.

30. The process according to claim 29, wherein said first ion beam has a beam energy selected to provide negligible physical etching of said patterned upper magnetic pole layer relative to etching of said gap layer.

31. The process according to claim 30, wherein said first ion beam has a beam energy of about 300 electron volts.

32. The process according to claim 1, wherein the second ion beam is generated from a plasma produced from a mixture of precursor gases including an inert gas and a gas containing oxygen.

33. The process according to claim 32, wherein said inert gas and said gas containing oxygen have a mass flow rate ratio of inert gas to oxygen in the range of about 1:

4 to about 2;

1.

34. The process according to claim 1, wherein said second ion beam is extracted from a plasma produced from at least one precursor gas including at least one gas selected from the group consisting of O2, N2O, NO2, and O3, and mixtures thereof.

35. The process according to claim 1, wherein said first ion beam is extracted from a plasma produced from at least one precursor gas including at least one gas selected from the group consisting of CF4, CHF3, CH2F2, CH3F, C2F6, C3F8, and mixtures thereof.

71. The process according to claim 12, wherein the first ion beam is generated using a first plasma produced using a fluorocarbon precursor gas mixed with an an inert precursor gas, and said second ion beam is generated using a second plasma produced by introducing an oxidizing gas into an extant plasma that comprises species derived from the inert precursor gas and is substantially devoid of species derived from the fluorohydrocarbon precursor gas.

72. The method according to claim 71, further comprising the step of maintaining a plasma having oxidizing species derived from the oxidizing gas within the first ion source after the second ion beam etching step is terminated.

36. An ion beam etching method, comprising the steps of:

bombarding a sample with a first ion beam extracted from an ion source that has a first plasma comprising a carbonaceous deposit forming species; and

introducing, after said first ion beam etching step has been initiated, an oxygen containing gas into an extant plasma of the ion source to provide a third plasma in said ion source, said third plasma having oxidizing species derived from said oxygen containing gas, and wherein said ion source contains a plasma continuously in time between said first plasma and said extant plasma.

37. The method according to claim 36, wherein said carbonaceous deposit forming species is derived from at least one fluorocarbon precursor gas used to form said first plasma.

38. The method according to claim 37, wherein said at least one fluorocarbon precursor gas includes at least one gas selected from the group consisting of CF4, CHF3, CH2F2, CH3F, C2F6, C3F8, and mixtures thereof.

39. The method according to claim 36, wherein said extant plasma is said first plasma.

40. The method according to claim 39, wherein during said introducing step, said carbonaceous deposit forming species is eliminated from the extant plasma.

41. The method according to claim 36, wherein said first plasma includes an inert gas species, and further comprising the step of eliminating the carbonaceous deposit forming species from the first plasma to provide said extant plasma, which comprises said inert gas and is substantially devoid of said carbonaceous deposit forming species, prior to performing said introducing step.

42. A thin film magnetic head comprising a layer having a pattern delineated using the ion beam etching method of claim 36.

43. The method according to claim 36, further comprising the step of bombarding the sample with a second ion beam extracted from said ion source containing said third plasma having said oxidizing species.

44. The method according to claim 43, wherein said first ion beam is directed at a first angle of incidence relative to a sample etched thereby, and wherein said second ion beam is directed at a second angle of incidence relative to the sample, said second angle of incidence not equal to said first angle of incidence.

45. The method according to claim 44, wherein said sample includes a first material and a second material, and said first angle of incidence is selected to enhance the selective etching of said second material relative to said first material.

46. The method according to claim 44, wherein said second angle of incidence is selected to enhance the selective removal of carbonaceous deposits capable of being formed on said sample during the bombardment by said first ion bean.

47. The method according to claim 44, wherein said first angle of incidence is less than about 45 degrees relative to a sample normal, and wherein said second angle of incidence is greater than about 60 degrees relative to the sample normal.

48. The method according to claim 43, further comprising the step of maintaining a plasma having said oxidizing species within said ion source after said second ion beam etching step is terminated.

49. The method according to claim 36, further comprising the step of bombarding the sample with a second ion beam extracted from a second ion source having a plasma containing an oxidizing species.

50. The method according to claim 49, wherein said first ion beam and said second ion beam bombard the sample during an overlapping time period.

51. The method according to claim 36, wherein said third plasma is maintained in the ion source for a period of time that is a factor of about 1.5 to about 2.5 greater than the period of time that said first plasma is resident in the ion source.

52. The method according to claim 36, wherein said sample includes a first material and a second material, and the beam energy of said first ion beam is selected to enhance the selective etching of said second material relative to said second material, said first ion beam including a species that is chemically reactive with said second material and substantially chemically nonreactive with said first material.

53. A process for ion beam etching of a substrate having a structure comprising a first layer and a second layer, said process comprising the steps of:

generating in an ion source a plasma including a species capable of forming carbonaceous deposits in said ion source;

impinging an ion beam extracted from said plasma onto said substrate to selectively etch said second layer at a rate greater than about two times the rate of etching said first layer, said ion beam having species that chemically react with a material included in said second layer; and

wherein said selectivity is substantially repeatable upon independent executions of said process.

54. The process according to claim 53, wherein said plasma is formed from a precursor gas, or precursor gas mixture, that includes at least one fluorocarbon gas.

55. The process according to claim 54, wherein said plasma is formed from a precursor gas mixture that includes a fluorocarbon gas and a noncarbon-containing hydrogen-containing gas.

56. The process according to claim 53, wherein said plasma is formed from a precursor gas mixture that includes a hydrocarbon gas and a noncarbon-containing fluorine-containing gas.

57. The process according to claim 53, wherein said first layer includes a material selected from the group consisting of NiFe, FeN, FeZN, FeTaN, CZT, Mn, Fe, Co, Ni, Cr, Ti, W, GaAs, GaN, AlGaAs, crystalline Si, amorphous Si, photoresist, polyimide, polymer, and elemental carbon allotropes.

58. The process according to claim 53, wherein said second layer includes a material selected from the group consisting of alumina, SiO₂, Si₃N₄, AlN, LiNO3, and ferroelectrics.

59. The process according to claim 53, wherein said plasma is formed from at least one precursor gas at least one of which is a fluorocarbon, said first layer includes permalloy, and said second layer includes alumina.

60. The process according to claim 59, wherein said fluorocarbon is CHF3.

61. The process according to claim 53, wherein said first layer is amorphous silicon and said second layer is SiO2.

62. The process according to claim 61, wherein said fluorocarbon based source gas includes CHF3, and said first ion beam selectively etches said SiO2 at a rate that is about twenty times greater than the rate that said first ion beam etches said amorphous silicon.

63. The process according to claim 53, wherein said first layer is Pt and said second layer is PZT.

64. The process according to claim 53, wherein said ion beam impinges on said sample at an incidence angle selected to substantially optimize the selectivity of etching said second layer relative to etching said first layer.

65. The process according to claim 53, further comprising the step of forming a second plasma in said ion source to remove carbonaceous deposits formed in the ion source by said plasma, said second plasma including an oxidizing species.

66. The process according to claim 65, wherein said second plasma is formed from at least one precursor gas at least one of which is selected from the group consisting of O2, N2O, NO2, and O3, and mixtures thereof.

67. A process for fabricating a thin film magnetic head, comprising the steps of:

forming a structure comprising a lower magnetic pole layer, a gap layer overlying the lower magnetic pole layer, and a patterned upper magnetic pole layer over the gap layer;

bombarding said structure with a first ion beam extracted from a first ion source, the first ion beam operative in etching the gap layer to expose a portion thereof; and

bombarding said structure, including the portion of the gap layer exposed by etching the gap layer, with a second ion beam that includes an oxidizing species.

68. The process according to claim 67, wherein said step of etching the gap layer with said first ion beam etches a fraction of the initial thickness of said gap layer, and further comprising the step, after said step of bombarding said structure with the second ion beam, of repeating said steps of etching the gap layer followed by bombarding said structure with the second ion beam at least until the entire thickness of the gap layer is etched.

69. The process according to claim 67, wherein said second ion beam is generated using said first ion source.

70. The process according to claim 69, wherein the first ion beam is generated using a first plasma produced using a fluorocarbon precursor gas, and said second ion beam is generated using a second plasma produced by introducing an oxidizing gas into the first plasma while the fluorocarbon precursor gas is eliminated.

73. The process according to claim 67, wherein said second ion beam is generated using a second ion source that is independent of the first ion source.

74. The process according to claim 73, wherein said first and second ion beams impinge on said structure during an overlapping time period.

75. The method according to claim 73, further comprising the step of generating a plasma from an oxidizing precursor gas within the first ion source after terminating said first ion beam.

76. An ion beam etching method, comprising the steps of:

bombarding a sample with a first ion beam extracted from an ion source that has a first plasma comprising a carbonaceous species; and

introducing, after said first ion beam etching step has been initiated, an oxygen containing gas into an extant plasma of the ion source to provide a third plasma in said ion source, said third plasma having oxidizing species derived from said oxygen containing gas, and wherein said ion source contains a plasma continuously in time between said first plasma and said extant plasma.

77. The method according to claim 76, wherein said first plasma is derived from at least one fluorocarbon precursor gases.

78. The method according to claim 76, wherein said extant plasma is said first plasma.

79. The method according to claim 78, wherein during said introducing step, said carbonaceous species is eliminated from the extant plasma.

80. The method according to claim 76, wherein said first plasma includes an inert gas species, and further comprising the step of eliminating the carbonaceous species from the first plasma to provide said extant plasma, which comprises said inert gas and is substantially devoid of said carbonaceous species, prior to performing said introducing step.

81. The method according to claim 76, further comprising the step of bombarding the sample with a second ion beam extracted from said ion source containing said third plasma having said oxidizing species.

82. The method according to claim 81, further comprising the step of maintaining a plasma having said oxidizing species within said ion source after said second ion beam etching step is terminated.

83. The method according to claim 76, further comprising the step of bombarding the sample with a second ion beam extracted from a second ion source having a plasma containing an oxidizing species.

84. The method according to claim 83, wherein said first ion beam and said second ion beam bombard the sample during an overlapping time period.

85. A process for ion beam etching of a substrate having a structure comprising a first layer and a second layer, said process comprising the steps of:

generating in an ion source a plasma that includes a carbon-containing species;

impinging an ion beam extracted from said plasma onto said substrate to selectively etch said second layer at a rate greater than about two times the rate of etching said first layer, said ion beam having species that chemically react with a material included in said second layer; and

wherein said selectivity is substantially repeatable upon independent executions of said process.

86. The process according to claim 85, wherein said plasma is formed from a precursor gas, or precursor gas mixture, that includes at least one fluorocarbon gas.

87. The process according to claim 86, wherein said plasma is formed from a precursor gas mixture that includes a fluorocarbon gas and a noncarbon-containing hydrogen-containing gas.

88. The process according to claim 85, wherein said plasma is formed from a precursor gas mixture that includes a hydrocarbon gas and a noncarbon-containing fluorine-containing gas.

89. The process according to claim 85, further comprising the step, after generating said plasma, of forming a second plasma that includes an oxidizing species.