Plasma enhancement apparatus and method for physical vapor deposition
DCFirst Claim
1. A plasma enhancement apparatus for use in combination with an electric arc vapor deposition system having a vacuum chamber, a consumable cathode source of coating material defining a cathode evaporation surface and an anode operable with the vacuum chamber, means for supporting a substrate to be coated in spaced line-of-sight relation to said cathode, said line-of-sight extending along an axis line extending between said cathode evaporation surface and said substrate, means for initiating and sustaining an electric arc between the cathode evaporation surface and said anode to create a column of plasma material projecting in line-of-sight manner along said axis line in a vacuum space extending from said cathode evaporation surface toward said substrate, comprising:
- field generating means mounted relative to said cathode evaporation surface and said substrate, so as to maintain said line-of-sight therebetween, for generating a magnetic field having magnetic field lines arranged around said axis line and between said cathode evaporation surface and said substrate and of a configuration whereby said field lines are constricted in at least a portion of said vacuum space;
said magnetic field being further characterized by having;
a. strength and orientation relative to said cathode evaporation surface that defines the intensity and confined movement of an arc spot of said arc over said cathode evaporation surface so as to minimize the generation of macroparticles at said cathode evaporation surface and to minimize their presence in said column of plasma material projected therefrom; and
b. strength and orientation that energizes electrons of said column of plasma material within at least a portion of said vacuum space, sufficiently to cause macroparticle vaporization therein, and that significantly increases the ionization, ionic charge and ionization fraction of said column of plasma material at said substrate;
whereby highly ionized substantially macroparticle reduced coating material from said cathode source impinges upon said substrate.
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Abstract
The present invention provides a plasma enhancement method and apparatus for electric arc vapor deposition. The plasma enhancement apparatus is positioned to act upon plasma generated from a plasma source before the plasma reaches a substrate to be coated by the plasma. The plasma enhancement apparatus includes a magnet disposed about a magnet axis and defining a first aperture, and a core member disposed about a core member axis and at least partially nested within the first aperture. The core member defines a second aperture, and the plasma enhancement apparatus is arranged and configured in such a manner that the evaporated cathode source material passes from the cathode source and through the second aperture toward the substrate to be coated by the evaporated cathode source material. The plasma is favorably conditioned as it passes through the plasma enhancement apparatus.
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Citations
38 Claims
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1. A plasma enhancement apparatus for use in combination with an electric arc vapor deposition system having a vacuum chamber, a consumable cathode source of coating material defining a cathode evaporation surface and an anode operable with the vacuum chamber, means for supporting a substrate to be coated in spaced line-of-sight relation to said cathode, said line-of-sight extending along an axis line extending between said cathode evaporation surface and said substrate, means for initiating and sustaining an electric arc between the cathode evaporation surface and said anode to create a column of plasma material projecting in line-of-sight manner along said axis line in a vacuum space extending from said cathode evaporation surface toward said substrate, comprising:
- field generating means mounted relative to said cathode evaporation surface and said substrate, so as to maintain said line-of-sight therebetween, for generating a magnetic field having magnetic field lines arranged around said axis line and between said cathode evaporation surface and said substrate and of a configuration whereby said field lines are constricted in at least a portion of said vacuum space;
said magnetic field being further characterized by having;a. strength and orientation relative to said cathode evaporation surface that defines the intensity and confined movement of an arc spot of said arc over said cathode evaporation surface so as to minimize the generation of macroparticles at said cathode evaporation surface and to minimize their presence in said column of plasma material projected therefrom; and b. strength and orientation that energizes electrons of said column of plasma material within at least a portion of said vacuum space, sufficiently to cause macroparticle vaporization therein, and that significantly increases the ionization, ionic charge and ionization fraction of said column of plasma material at said substrate;
whereby highly ionized substantially macroparticle reduced coating material from said cathode source impinges upon said substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- field generating means mounted relative to said cathode evaporation surface and said substrate, so as to maintain said line-of-sight therebetween, for generating a magnetic field having magnetic field lines arranged around said axis line and between said cathode evaporation surface and said substrate and of a configuration whereby said field lines are constricted in at least a portion of said vacuum space;
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16. A process of enhancing electric arc vapor deposition coating of a substrate within a vacuum deposition chamber by a plasma of coating material from a consumable cathode, comprising the steps of:
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a. operatively arranging an evaporation surface of a consumable cathode source of coating material in line-of-sight position relative to a substrate within a vapor deposition chamber; b. striking and maintaining an electric arc within said vapor deposition chamber, between said cathode evaporation surface and an anode, to create a plasma of coating material from said cathode evaporation surface said electric arc forming one or more arc spots on said cathode evaporation surface; c. directing a column of said plasma in line-of-sight manner along an axis line extending from said cathode evaporation surface toward said substrate; d. magnetically controlling the current density and movement of said arc spot over said cathode evaporation surface to reduce formation of macroparticles and to minimize their presence in said plasma column; e. magnetically energizing electrons in said line-of-sight plasma column sufficiently to cause macroparticle vaporization therein and to significantly increase ionization, the ionic charge and the ionization fraction of said plasma; and f. impinging said column of energized plasma onto said substrate to form a smooth, dense and virtually macroparticle free coating on said substrate. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method of forming virtually macroparticle free coatings on a substrate within an electric arc vapor deposition system which creates a plasma of coating material by striking an electric arc between a consumable cathode and an anode within an evacuated deposition chamber, comprising the steps of:
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a. evacuating the deposition chamber to a predetermined pressure; b. creating and maintaining an electric arc between an evaporation surface of a cathode and an anode, to produce a plasma of coating material projecting from said evaporation surface; c. directing a column of said plasma of coating material in line-of-sight manner along an axis line between said cathode evaporation surface and a substrate within said deposition chamber; d. magnetically controlling the intensity and movement of the electric arc on the cathode evaporation surface so as to minimize generation of macroparticle emission into the column of plasma material; and e. applying a magnetic field to said column of plasma material, by passing the column of plasma material through a core configuration while maintaining said line-of-sight manner of said column of plasma material toward the substrate, to increase the core energy of electrons of said column of plasma material sufficiently to vaporize macroparticles within said column;
whereby said column of plasma material arrives virtually macroparticle free at said substrate. - View Dependent Claims (23, 24, 25, 26)
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27. An enhanced electric arc vapor deposition system comprising:
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a. a vacuum deposition chamber; b. an anode operatively associated with said deposition chamber; c. a consumable cathode source mounted within said deposition chamber, said cathode source defining an evaporation surface; d. a substrate; e. means for supporting said substrate in spaced line of-sight relation to said cathode evaporation surface within said vacuum deposition chamber; f. means operatively connected to said anode and said cathode source for establishing and maintaining an electric arc between said cathode evaporation surface and said anode, thereby creating a column of plasma material projecting in line-of-sight manner along an axis line extending from said cathode evaporation surface toward said substrate; and g. magnetic field generating means mounted so as to maintain the line-of-sight relation between said cathode evaporation surface and said substrate, for creating a magnetic field having; i. strength and orientation relative to said cathode evaporation surface to control the intensity and movement of said arc over said cathode evaporation surface so as to minimize emission of macroparticles from said cathode evaporation surface into said column of plasma material; and ii. strength and orientation relative to said column of plasma material to increase the core energy of electrons of said column of plasma material sufficiently to cause macroparticle vaporization therein, and to significantly increase the ionization, the ionic charge and the ionization fraction of said column of plasma material at said substrate; whereby highly ionized reduced macroparticle plasma material from said cathode impinges upon said substrate. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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34. The method of making a hard, smooth film coating directly on a substrate by electric arc vapor deposition from a solid carbon source, said method comprising the steps of:
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a. forming a line-of-sight plasma within a deposition zone, under vacuum conditions, by means of an electric arc passing between an arc spot on a consumable carbon-based cathode and an anode, said line-of-sight extending in the deposition zone between said cathode and a substrate spaced therefrom; b. magnetically controlling the arc at the cathode to increase the stability and lifetime of the arc spot on the cathode, thereby leading to reduction of macroparticle emission; c. magnetically converging the line-of-sight plasma by a magnetic field having strength and orientation for increasing the energy of electrons in said plasma core sufficient to atomize macroparticles; d. preparing a substrate within the deposition zone by impacting the line-of-sight plasma from step (c) onto a surface of the substrate to nucleate the substrate surface in preparation for coating; e. coating the nucleated substrate surface with said line-of-sight plasma from step (c); and f. recovering from the plasma deposition zone said substrate having an adherent diamond-like carbon coating directly thereon, said coating being homogeneous, dense, smooth and extremely hard. - View Dependent Claims (35, 36, 37, 38)
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Specification