JP2013032560A - Vacuum arc-type evaporation source and vacuum arc deposition method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum arc-type evaporation source capable of controlling macroparticles adhered to a substrate by a vacuum arc deposition method.SOLUTION: The vacuum arc-type evaporation source includes a rod-like or plate-like cathode 3 comprising a material to be evaporated, a spacer part 16 provided on the surface opposite to the evaporation surface of the cathode, and a backing plate 10 to which the spacer part 16 is attached, wherein the cross-sectional area perpendicular to the axial direction of the spacer part 16 is made smaller than the cross-sectional area perpendicular to the thickness direction of the cathode.

Description

  The present invention relates to an evaporation source and a vapor deposition method that suppress the generation of macro particles that are generated from a cathode by a vacuum arc vapor deposition method and adhere to a substrate that covers a film.

  In recent years, the vacuum arc deposition method is a film forming method in which an arc discharge is generated between an anode and a cathode, the cathode material is evaporated and deposited on a substrate, and the plasma density is high and the productivity is excellent. It has features and is increasingly used for cutting tools and sliding parts.

  However, when plasma is generated by arc discharge, in addition to ions and electrons, a large number of particles called macro particles, which reach several μm, are generated from the cathode, and these particles adhere to the substrate covering the film. It is known that film peeling and film characteristics are deteriorated. (For example, see Patent Document 1)

  In order to prevent peeling of the coating film due to these particles and deterioration of coating properties, a magnetic field such as a magnetic coil is used to generate a deflection magnetic field between the cathode and the substrate, and only the plasma flow excluding the particles is moved along the deflection magnetic field. As a magnetic filter method, for example, Patent Document 2 proposes a vapor deposition apparatus that transports in the direction of the substrate covering the film and prevents the adhesion of the particles to the substrate. Further, Patent Document 2 discloses that the particles are reduced by an adhesion filter and an electromagnetic filter capable of applying a voltage to the plasma transport path.

  Next, FIG. 5 shows a schematic diagram of an example of a vacuum arc deposition apparatus using a conventional evaporation source. In the figure, 1 is a vacuum chamber, 2 is a vacuum chamber wall, 3 is a cathode, 4 is a substrate holder, 5 is a substrate, 6 is an arc power source, 7 is a bias power source, and 8 is an arc plasma.

Next, a case where film formation is performed using this apparatus will be described as an example.
The vacuum chamber 1 is exhausted to a predetermined degree of vacuum by an exhaust system such as a turbo molecular pump or a rotary pump (not shown). Thereafter, arc discharge is started by the arc power source 6 between the cathode 3 made of the evaporation material provided on the chamber wall 2 and the vacuum chamber 1, and the evaporation material is evaporated from the cathode 3 and placed on the substrate holder 4. Film formation is performed on the placed substrate 5. Usually, when there are a large number of base materials 5, a plurality of cathodes 3 are provided on each chamber wall of the vacuum chamber wall 2 or are provided in multiple stages on one chamber wall, and the base material holder 4 revolves with respect to the cathode. I try to let them. Note that the chamber wall 2 is water-cooled during film formation.

  At this time, for example, if the cathode material is graphite, a plasma 8 of carbon ions and electrons including the macro particles generated from the cathode 3 is generated, and the base holder 4 and the substrate are caused by a negative bias voltage applied from the bias power source 7. A DLC (diamond-like carbon) film containing macro particles is formed on the surface of the base material 5 attracted to the material 5 and held on the base material 5 held by the base material holder 4.

Next, an example of the evaporation source when the cathode of the vacuum arc vapor deposition apparatus shown in FIG. 5 is graphite will be described with reference to the schematic diagram of FIG.
The evaporation source includes a cathode 3, a backing plate 10, a flange 11, and the like.

  The cathode 3 is rod-shaped or plate-shaped, and is fitted or screwed to a plate-shaped backing plate 10 to be integrated, and is fitted or screwed via a sealing material such as an O-ring (not shown) to be flange 11. It is attached to the attachment part 12 with the backing play. The cathode 3, the backing plate 10, and the flange 11 that are attached and integrated in this manner are inserted into the chamber 1 through the hole 15 of the vacuum wall 2, and the flange portion 13 of the flange is interposed through an electrically insulating vacuum seal material 14. The arc voltage is applied to the cathode 3 by the arc power source 6 through the flange 11 and the backing plate.

  The backing plate 10 is necessary when the material of the cathode is porous such as graphite (graphite), but is not necessary if it is a dense metal or the like.

  In the vacuum arc deposition apparatus using the magnetic filter disclosed in Patent Document 2, the evaporation source is generally as shown in FIG.

  Moreover, although not shown in figure, the inside of the backing plate 10 and the flange 11 is water-cooled for cooling. Therefore, as described above, the backing plate 10 and the flange 11 are sealed with an O-ring or the like.

  Because of the above configuration, the heat on the evaporation surface of the cathode 3 due to arc discharge escapes through the backing plate, so the temperature of the evaporation surface does not rise, and the emission of thermoelectrons is less, resulting in the generation of macro particles. If the affected arc current is made smaller, the arc discharge cannot be maintained stably, and as a result, the generation of macro particles cannot be suppressed.

Japanese Patent Laid-Open No. 08-260132 JP 2002-25794 A

  This invention makes it a subject to provide the arc type evaporation source which suppresses generation | occurrence | production of the macro particle from the said cathode from the structure of an evaporation source.

  In order to solve the above-mentioned problems, the inventors have arrived at the invention of an arc evaporation source capable of stably performing arc discharge even at an arc current of 30 A or less, from the knowledge that the arc current should be reduced to suppress the macro particles. .

  That is, the arc evaporation source of the present invention comprises a rod-like or plate-like cathode made of a substance to be evaporated, a backing plate holding the cathode, the cathode and the backing plate, and a thickness direction of the cathode. And a spacer portion having a cross-sectional area perpendicular to the axial direction that is smaller than a cross-sectional area perpendicular to the axial direction.

  Further, in order to make it difficult for the heat of the cathode to escape and increase the generation of thermoelectrons, the spacer portion is made of a material having a lower thermal conductivity than the material of the cathode.

The present invention is characterized in that the cathode has an integral shape including the spacer portion.
It is characterized by that.

  Further, the present invention is characterized in that the flange has an integral shape including the spacer portion.

  The cathode has an integral shape including the spacer portion and a mounting portion to the backing plate.

  Further, in a vacuum arc deposition method in which film formation is performed by evaporating a cathode material by arc discharge, an axis smaller than a cross-sectional area perpendicular to the thickness direction of the cathode between the cathode and a backing plate holding the cathode. A spacer portion having a cross-sectional area perpendicular to the direction is provided, and film formation is performed at an arc current of 30 A or less.

According to the present invention, it is difficult for heat generated at the cathode of the arc evaporation source to be transmitted to the backing plate, and the evaporation surface of the cathode is raised, so that generation of thermoelectrons is increased.
As a result, since it becomes possible to operate stably with a low arc current, it is possible to provide an arc evaporation source and a vacuum arc deposition method capable of suppressing the generation of macro particles from the cathode.

It is a schematic sectional drawing which shows a part of evaporation source which is one Embodiment of this invention. It is a schematic sectional drawing which shows a part of evaporation source which is other embodiment of this invention. It is a schematic sectional drawing which shows a part of evaporation source which is further another embodiment of this invention. It is a schematic sectional drawing which shows a part of evaporation source which is further another embodiment of this invention. It is the schematic of an example of the conventional vacuum arc vapor deposition apparatus. It is a schematic sectional drawing of an example of the evaporation source used for the conventional vacuum arc vapor deposition apparatus.

Embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the code | symbol in the figure showing embodiment of this invention uses the same code | symbol, when it is the same as each part of the above-mentioned conventional evaporation source.
FIG. 1 shows a part of an arc evaporation source according to an embodiment of the present invention. Since the flange 11 is the same as that of the prior art, it is a diagram in which it is omitted.

  The cathode 3 is not directly attached to the backing plate 10 as in the conventional arc evaporation source described above, but is backed up via a rod-like spacer portion 16 provided on the opposite surface of the evaporation surface 17 of the rod-like or plate-like cathode 3. It is attached to the plate 10. In the present embodiment, the cathode 3, the spacer portion 16, and the backing plate 10 are separate components, and the spacer portion is attached to the cathode 3 and the backing plate, for example, by screwing.

  The cross-sectional area perpendicular to the axial direction of the rod-shaped spacer portion 16 is smaller than the cross-sectional area perpendicular to the thickness direction of the cathode.

  The spacer portion may be made of a conductive material and may be the same material as the cathode or a different material. However, in order to make it difficult for heat generated by the arc to be transmitted to the backing plate, a material having a low thermal conductivity is used. Is particularly desirable. For example, if the cathode is graphite, stainless steel such as SUS304 is preferable.

FIG. 2 shows another embodiment of the present invention.
The cathode 3 has an integrated shape including a rod-shaped spacer portion 16 having a cross-sectional area perpendicular to the axial direction of the spacer portion 16 smaller than a cross-sectional area perpendicular to the thickness direction of the cathode.

  FIG. 3 shows still another embodiment of the present invention. A rod-shaped spacer portion 16 having a cross-sectional area perpendicular to the axial direction of the spacer portion 16 is smaller than a cross-sectional area perpendicular to the thickness direction of the cathode. The integrated shape is included.

Furthermore, FIG. 4 shows another embodiment of the present invention.
The cathode 3 has an integrated shape including a rod-shaped spacer portion 16 having a cross-sectional area perpendicular to the axial direction of the spacer portion 16 smaller than a cross-sectional area perpendicular to the thickness direction of the cathode and a mounting portion to the backing plate 10.

In any of the embodiments, it is desirable to make the spacer portion 16 as long as possible. This is because it is difficult for heat from the arc discharge to escape from the cathode 3 to the backing plate 10.
Further, when the cathode is large, the spacer portions may be provided at a plurality of locations.

  In the above embodiment, the backing plate 10 and the flange 11 are provided separately, but they may be integrated.

  By attaching the cathode 3 via the spacer as in the above-described embodiment, the temperature of the cathode 3, particularly the surface temperature, rises, and more thermoelectrons are emitted from the evaporation surface 17 during arc discharge. The arc discharge can be maintained even if the discharge current is reduced. As a result, the generation of macro particles can be suppressed.

<Example>
Using the evaporation source of the embodiment shown in FIG. 1, a DLC film is formed on a substrate at a low arc current, and the discharge stability and the size and number of macro particles generated from the cathode after film formation are represented. The surface roughness (average surface roughness: Ra) of the film formation surface of the base material considered as an index was measured.

The film forming conditions are as follows.
(1) Cathode material: Graphite (graphite)
(2) Size of cathode material: diameter 64 mm x thickness 20 mm
(3) Spacer material: SUS304
(4) Spacer size: 10mm diameter x 5mm thickness
(5) Base material: Si wafer (6) Arc discharge condition (a) Chamber internal pressure: 1 × 10 ⁻³ Pa or less (b) Process gas: None (c) Arc current: 20A, 30A
(7) Film thickness: 250 nm
As a comparative example, film formation was performed using the conventional evaporation source shown in FIG. 6 under the same shape cathode and the same arc discharge conditions.
Table 1 shows the results.

  When the evaporation source of the present invention is used, arc discharge at an arc current of 20 A, which was not possible with a conventional evaporation source, is stably maintained, and the surface roughness that is considered to be caused by an increase in macro particles is small. It is clear. Furthermore, it can be seen that the surface roughness is also smaller at the arc current 30A than when the conventional evaporation source is used.

  In the examples, graphite (graphite) is used as the cathode material, but it is needless to say that the cathode material of the evaporation source of the present invention can be widely applied to metals and alloys.

  As mentioned above, although embodiment of this invention was described, these are only some embodiments, This invention can be implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art.

INDUSTRIAL APPLICABILITY The present invention can be used as an evaporation source of a vacuum arc vapor deposition apparatus for film formation of cutting tools, sliding parts, molds and the like that require good adhesion, wear resistance, and sliding characteristics.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Vacuum chamber wall 3 Cathode 4 Base material holder 5 Base material 6 Arc power supply 7 Bias power supply 8 Arc plasma 10 Backing plate 11 Flange 12 Flange backing plate attachment part 13 Flange flange part 14 Electrical insulating vacuum seal material 15 Vacuum wall hole 16 Spacer portion 17 Cathode evaporation surface 18 Attaching portion of cathode to backing plate

Claims (6)

  A rod-like or plate-like cathode made of a material to be evaporated, a backing plate holding the cathode, the cathode and the backing plate are connected, and perpendicular to an axial direction smaller than a cross-sectional area perpendicular to the thickness direction of the cathode A vacuum arc evaporation source including a spacer section having a variable cross-sectional area.   The vacuum arc evaporation source according to claim 1, wherein the spacer portion is made of a material having a thermal conductivity smaller than that of the cathode.   The vacuum arc evaporation source according to claim 1, wherein the cathode has an integral shape including the spacer portion.   The arc evaporation source according to claim 1, wherein the backing plate has an integral shape including a spacer portion.   The vacuum arc evaporation source according to claim 1, wherein the cathode has an integral shape including the spacer portion and a mounting portion to a backing plate. In a vacuum arc deposition method in which film formation is performed by evaporating a cathode material by arc discharge, an axial direction smaller than a cross-sectional area perpendicular to the thickness direction of the cathode between the cathode and a backing plate holding the cathode. A vacuum arc vapor deposition method, characterized in that a spacer portion having a vertical cross-sectional area is provided and a film is formed at an arc current of 30 A or less.

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