Powder film forming apparatus and powder film forming method

Abstract

To provide a powder film deposition apparatus capable of efficiently forming a film on the surface of powder by efficiently agitating the powder in a vessel for subjecting the surface of the powder to film deposition.SOLUTION: A powder film deposition apparatus 1 includes: an apparatus main body including a vessel 10 having a bottom surface 13, having an upward conveying path 31 for conveying a powder F arranged on the bottom surface 13 of the vessel 10 upward in a region except a powder falling space S in the vessel 10 and constituted so as to fall the powder F conveyed upward along the upward conveying path 31 on the bottom surface 13 through the powder falling space S; and a film deposition source forming a state capable of depositing a film deposition material on the surface of the powder F. The film deposition source is constituted so as to supply the film deposition material having a state capable of depositing the film deposition material into a film in at least one of a position facing in the vertical direction to the bottom surface 13 above the vessel 10 and the inside of the vessel 10 to the bottom surface 13 through the powder falling space S.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a powder film forming apparatus and a powder film forming method for performing a film forming process on a surface of powder. [Background technology]

[0002] As a technique for forming a film on the surface of powder, for example, Patent Document 1 discloses a method for coating fine powder by sputtering. This method includes subjecting fine powder of metal, ceramic or plastic to reduced pressure heat treatment in an inert atmosphere, placing the heat-treated fine powder in a rotating container containing a sputtering source and rotating the container to form a fluidized bed of the fine powder, and forming a coating on the fluidized fine powder by sputtering while the container is rotating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-153068 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in order to efficiently form a film on the surface of the powder, it is necessary to sufficiently agitate the powder in a container for the film formation process. However, the technology disclosed in Patent Document 1 does not necessarily agitate the powder in the container sufficiently. Specifically, the technology of Patent Document 1 agitates the powder by rotating a rotating container with the fine powder placed at the bottom of the rotating container, so the fine powder (powder) only moves along the bottom and side of the rotating container near the side that is continuous with the bottom. Such a movement of the powder alone may not be sufficient to agitate the powder.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a powder coating apparatus and a powder coating method that can efficiently form a film on a powder surface by efficiently stirring the powder in a container for performing a film coating process on the powder surface. [Means for solving the problem]

[0006] A powder film-forming apparatus according to one aspect of the present disclosure is an apparatus for performing a film-forming process on a surface of powder, and comprises an apparatus main body including a container having a bottom surface on which powder can be placed, in which a powder drop space is formed within the container, the powder placed on the bottom surface of the container being a space continuing upward from the bottom surface, an upper transport path is formed for transporting powder placed on the bottom surface of the container upward within the container and in an area other than the powder drop space, and the apparatus main body is configured to be able to drop powder transported upward along the upper transport path through the powder drop space onto the bottom surface; and a film-forming source for bringing a film-forming material into a film-formable state capable of forming a film on the surface of the powder, the film-forming source being configured to bring the film-forming material into the film-formable state at least one of a position above the container and vertically facing the bottom surface and within the container, and to supply the film-formed material to the bottom surface through the powder drop space.

[0007] In this powder film forming apparatus, the film forming source makes the film forming material in a film-forming state at least one of a position above the container facing the bottom surface in the vertical direction and inside the container, and supplies the film forming material in the film-forming state to the bottom surface through the powder drop space. That is, the film forming material in the film-forming state above the bottom surface can directly act on the powder on the bottom surface by moving downward through the powder drop space, and can efficiently contact the surface of the powder on the bottom surface. Moreover, since the upper transport path of the device body is formed in the container and in an area other than the powder drop space, it does not interfere with the movement of the powder falling toward the bottom surface through the powder drop space, and the powder arranged on the bottom surface of the container can be transported upward so as not to interfere with the movement of the film forming material in the film-forming state supplied to the bottom surface through the powder drop space. Therefore, this powder film-forming device transports the powder upward and then returns the transported powder to the bottom surface through the powder falling space, creating a smooth flow of powder within the container and ensuring that the powder is circulated, thereby efficiently stirring the powder, and efficiently bringing the film-forming material in a state ready for film-forming into contact with the powder on the bottom surface, thereby efficiently forming a film on the surface of the powder.

[0008] The film formation source is preferably configured to supply the film formation material in the film-forming state to at least a portion of the upper transport path.

[0009] In this embodiment, the film-forming material in a film-forming state is not only supplied to the bottom surface of the container, but also to at least a part of the upper transport path in the container. As a result, the film-forming process is not only performed on the powder on the bottom surface, but also on at least a part of the powder on the upper transport path. This makes it possible to form a film more efficiently on the surface of the powder. In addition, the following can be exemplified as specific embodiments in which the film-forming material in a film-forming state can be supplied to at least a part of the upper transport path. For example, when there is no obstruction between at least a part of the upper transport path and the position where the film-forming source makes the film-forming material in a film-forming state, the film-forming material in a film-forming state can be supplied to at least the part of the upper transport path.

[0010] In the powder deposition apparatus, the upward conveying path includes a spiral conveying path extending upward in a spiral shape from the bottom surface, the apparatus body further includes a vibration generating unit that operates to vibrate the container to convey the powder placed on the bottom surface upward along the spiral conveying path, and it is preferable that the powder falling space is a space radially inward of the container than the spiral conveying path.

[0011] In this embodiment, the spiral conveying path for conveying the powder upward is formed in a spiral shape, so that the powder drop space can be formed in an area inside the spiral conveying path, that is, an area near the center of the container (for example, an area including the central axis of the container). Therefore, in this embodiment, the radially outer area in the container that does not interfere with the powder dropping toward the bottom through the powder drop space and the film-forming material that has become film-formable moving toward the bottom through the powder drop space is used as an area for providing the spiral conveying path, and the powder on the bottom can be conveyed upward along the spiral conveying path by the vibration of the container. In this embodiment, if there is no obstruction between at least a part of the spiral conveying path and the position where the film-forming source makes the film-forming material in a film-formable state, the film-forming material that has become film-formable can be supplied to the part of the spiral conveying path, and the powder on the part of the spiral conveying path can be subjected to a film-forming process.

[0012] In the powder deposition apparatus, the vibration generating unit is preferably configured to be capable of vibrating the container in a direction including a component in the direction of a central axis of the container and a component in a circumferential direction around the central axis.

[0013] In this embodiment, by vibrating the container in a direction in which the above-mentioned components are contained, the powder can be efficiently moved upward along the spiral transport path.

[0014] In the powder deposition apparatus, it is preferable that the upper conveying path further includes an inner guide path extending from the upper end so as to enable the powder transported to the upper end of the spiral conveying path to be guided to a region radially inward from the upper end.

[0015] In this embodiment, the inner guide path can further guide the powder transported to the upper end of the spiral transport path to a region radially inward from the upper end. This allows the drop point on the bottom surface of the powder dropping from the tip of the inner guide path to be closer to the center of the bottom surface. Therefore, a powder flow is formed in which the powder moves from the center of the bottom surface to the radially outer side of the bottom surface, and the moved powder reaches the entrance of the spiral transport path. As a result, the occurrence of a situation in which the powder is locally retained on the bottom surface is suppressed. This makes it possible to reliably circulate the powder in the container in the powder movement path that is continuous in the order of the center of the bottom surface, the radially outer region of the bottom surface, the spiral transport path, the inner guide path, and the powder drop space. This further promotes the stirring of the powder.

[0016] In this embodiment, the powder transported sequentially along the spiral transport path and the inner guide path sequentially falls from the tip of the inner guide path to the vicinity of the center of the bottom surface, and then moves radially outward on the bottom surface. By sequentially dropping the powder to the vicinity of the center of the bottom surface and moving the powder radially outward on the bottom surface, the powder can be dispersed over a wide area of ​​the bottom surface. When the powder is dispersed over a wide area of ​​the bottom surface, the surface area of ​​the powder on the bottom surface that can be contacted by the film-forming material that has become film-formable increases, so that the powder on the bottom surface can efficiently capture the film-forming material. This can further improve the efficiency of film formation on the surface of the powder.

[0017] More preferably, the inner guideway includes a portion that slopes downwardly towards a tip of the inner guideway.

[0018] In this embodiment, since the inner guide path includes a downwardly inclined portion as described above, the distance between the tip of the inner guide path and the center of the bottom surface can be made smaller. This prevents the powder falling from the tip of the inner guide path from diffusing to the surroundings before it reaches the bottom surface, making it easier to move the powder's falling point on the bottom surface closer to a desired position (e.g., the center of the bottom surface).

[0019] Moreover, the powder on the inclined portion as described above is more likely to move toward the tip of the inner guide path due to the action of gravity than, for example, powder on a horizontal surface. Therefore, even if the vibration generating unit vibrates the container in a direction including, for example, a component in the direction of the central axis and a component in the circumferential direction around the central axis, the powder on the inner guide path is reliably transported toward the tip. Specifically, it is as follows. The inner guide path extends from the upper end of the spiral transport path so that the powder transported to the upper end can be guided to a region radially inward from the upper end, and the tip of the inner guide path is located closer to the central axis than the spiral transport path, so that the circumferential vibration component in the inner guide path becomes smaller toward the tip of the inner guide path. Therefore, since the vibration in the direction of the central axis is the main vibration near the tip of the inner guide path, it may become difficult to transport the powder in the inner guide path toward the tip. Even in such a case, the powder on the inner guide path can be reliably transported toward the tip by the inner guide path including the inclined portion as described above.

[0020] In the powder deposition apparatus, it is preferable that the bottom surface of the container includes an inclined surface that slopes downward from the center of the bottom surface toward the outside in the radial direction, and the inner guide path is positioned so that the fall point of at least a portion of the powder falling from the tip of the inner guide path is the center of the bottom surface.

[0021] In this embodiment, the powder that falls from the tip of the inner guide path and reaches the center of the bottom surface is efficiently moved radially outward along the inclined surface of the bottom surface by the vibration of the container. This more effectively forms a powder flow in which the powder moves from the center of the bottom surface to the radially outward of the bottom surface and reaches the entrance of the spiral conveying path. As a result, the occurrence of a situation in which the powder is locally retained on the bottom surface is further suppressed, and the stirring of the powder is further promoted. This makes it possible to reliably circulate substantially all of the powder in the container along the powder movement path that is continuous in the order of the center of the bottom surface, the radially outer region of the bottom surface, the spiral conveying path, the inner guide path, and the powder falling space.

[0022] The spiral transport path preferably has a shape that, in a plan view, gradually moves away from the center of the container as it extends upward.

[0023] In this embodiment, the overlap between the upper region of the spiral conveying path and the lower region of the spiral conveying path in plan view can be reduced compared to a spiral conveying path that draws a spiral shape so that the distance from the center of the container is constant. That is, in this embodiment, the lower region of the spiral conveying path can be positioned radially inward relative to the upper region of the spiral conveying path in plan view, so that the film-forming material that has become ready for film formation is efficiently supplied not only to the powder in the upper region of the spiral conveying path but also to the powder in the lower region of the spiral conveying path.

[0024] The powder film forming apparatus is an apparatus that performs a film forming process on a surface of a powder by sputtering, and the film forming source includes a cathode for the sputtering, and the cathode may be positioned in a position that faces the bottom surface in the vertical direction across the powder falling space.

[0025] In this embodiment, the powder placed on the bottom surface and the cathode can be arranged to face each other in the vertical direction with the powder falling space in between. This allows the particles (e.g., atoms or molecules) flying out from the cathode to efficiently come into contact with the powder placed on the bottom surface and the powder falling through the powder falling space. As a result, a film can be efficiently formed on the surface of the powder.

[0026] The powder film forming apparatus may be an apparatus for performing a film forming process on a surface of powder by sputtering, and the film forming source may include at least one rotary cathode for the sputtering.

[0027] The powder film forming apparatus is an apparatus that performs a film forming process on the surface of a powder by sputtering, and it is preferable that the film forming source includes at least one rotary cathode for the sputtering, the at least one rotary cathode includes a cylindrical target, and the target is arranged in an orientation such that the central axis of the target faces vertically and at least a portion of the target is arranged horizontally opposite the spiral conveying path.

[0028] In this embodiment, the target is positioned with its central axis facing vertically, so that at least a portion of the target faces horizontally to the spiral transport path, and the film-forming material that is in a state suitable for film formation is efficiently supplied to the powder in the spiral transport path.

[0029] The powder coating apparatus is an apparatus that performs a coating process on a surface of a powder by arc ion plating, and the coating source includes a cathode for the arc ion plating, and the cathode may be arranged in a position that faces the bottom surface in the vertical direction across the powder falling space.

[0030] In this embodiment, the powder placed on the bottom surface and the cathode can be arranged to face each other in the vertical direction with the powder falling space in between. This allows the particles (e.g., ions) evaporated from the cathode to efficiently come into contact with the powder placed on the bottom surface and the powder falling through the powder falling space. As a result, a film can be efficiently formed on the surface of the powder.

[0031] In the powder deposition apparatus, it is preferable that an area of ​​the bottom surface overlapping with the powder falling space in a plan view has a size such that the cathode is included within the area in a plan view.

[0032] In a film formation process by sputtering or arc ion plating, particles (e.g., atoms or molecules) ejected from the cathode or particles (e.g., ions) evaporated from the cathode not only move downward parallel to the vertical direction from the cathode, but also move diagonally downward at a certain angle relative to the vertical direction so as to diffuse. Therefore, by making the area of ​​the bottom surface that overlaps with the powder drop space in a plan view larger than the cathode, the particles can come into contact with the powder over a wider area of ​​the bottom surface. As a result, a film can be formed more efficiently on the surface of the powder.

[0033] The powder film forming apparatus is an apparatus that performs a film forming process on a surface of a powder by plasma CVD, and the film forming source includes a plasma source for putting a raw material gas as the film forming material into a state in which a film can be formed, and the plasma source may be arranged in a position that is vertically opposite the bottom surface via the powder falling space.

[0034] In this embodiment, the powder placed on the bottom surface and the plasma source can be arranged to face each other in the vertical direction through the powder drop space. This allows the raw material gas that has been made into a film-forming state by the plasma source to efficiently contact the powder placed on the bottom surface and the powder falling through the powder drop space. As a result, a film can be efficiently formed on the surface of the powder. In this embodiment, the raw material gas that has been made into a film-forming state is, for example, a product generated by decomposing the raw material gas when the plasma source acts on the raw material gas.

[0035] It is preferable that the powder film forming apparatus further comprises a source gas supply unit that supplies the source gas to a region affected by the plasma source.

[0036] In this embodiment, the raw material gas supplied from the raw material gas supply unit is brought into a film-forming state in the region affected by the plasma source (e.g., the region directly below the plasma source), and then contacts the powder on the bottom surface, thereby efficiently forming a film on the surface of the powder.

[0037] In the powder deposition apparatus, it is preferable that the plasma source has an opening formed at a lower portion of the plasma source for discharging plasma generated inside the plasma source to the outside of the plasma source.

[0038] In this embodiment, the source gas is decomposed by the plasma discharged through the opening formed in the lower part of the plasma source, and can be efficiently converted into a state suitable for film formation.

[0039] In the powder deposition apparatus, it is preferable that the raw material gas supply section has a pipe arranged in a ring shape so as to surround the opening of the plasma source in a planar view, and is configured so as to be able to supply the raw material gas below the plasma source through a gas supply hole formed in the pipe.

[0040] In this embodiment, the pipe of the source gas supply unit is disposed so as to surround the opening of the plasma source in a plan view, so that the pipe does not impede the downward movement of the plasma emitted from the opening, thereby enabling the source gas supplied below the plasma source from the supply hole of the pipe to come into contact with the plasma emitted from the opening of the plasma source efficiently.

[0041] In the powder deposition apparatus, it is preferable that an area of ​​the bottom surface overlapping with the powder falling space in a plan view has a size such that the opening of the plasma source is included within the area in a plan view.

[0042] In a film forming process using plasma CVD, the raw material gas that has been made into a film-forming state by the plasma source not only moves downward parallel to the vertical direction from directly below the opening of the plasma source, but also moves so as to diffuse diagonally downward at a certain angle range with respect to the vertical direction. Therefore, by making the area of ​​the bottom surface that overlaps with the powder drop space in a plan view larger than the opening of the plasma source, the raw material gas that has been made into a film-forming state can come into contact with the powder over a wider area of ​​the bottom surface. As a result, a film can be formed more efficiently on the surface of the powder.

[0043] It is preferable that the powder film forming apparatus further includes an inert gas supply unit that supplies an inert gas into the container so that the source gas in the film-forming state is guided toward the bottom surface in the powder falling space.

[0044] In this embodiment, the source gas that has been turned into a film-forming state by the plasma source is guided to the bottom surface by the inert gas supplied from the inert gas supply unit, which makes it possible to more efficiently form a film on the surface of the powder.

[0045] It is preferable that the powder coating apparatus further includes a vacuum chamber that houses the container, the container having an upwardly open shape, and the coating material is brought into a coating-enabling state at least either above the container or inside the container within the vacuum chamber.

[0046] In this embodiment, the powder can be efficiently stirred by forming a series of powder flows as described above in the vacuum chamber, and the film-forming material in a film-forming state can be efficiently brought into contact with the powder on the bottom surface in the vacuum chamber. Therefore, in this embodiment, a film can be efficiently formed on the surface of the powder in a vacuum atmosphere.

[0047] In the powder deposition apparatus, it is preferable that the vacuum chamber has an internal space for accommodating the container, an upwardly opening chamber body, and a lid portion attached to the upper part of the chamber body in an openable and closable manner.

[0048] In this embodiment, the film formation process can be carried out with the lid portion closing the top of the chamber body, and consumable parts such as the target can be easily replaced with the lid portion open.

[0049] The powder deposition apparatus further includes a vacuum chamber that houses the container, the upward conveying path includes a spiral conveying path extending upward in a spiral shape from the bottom surface, and the apparatus main body further includes a vibration generating unit that operates to vibrate the container to convey the powder placed on the bottom surface upward along the spiral conveying path, and the vibration generating unit includes a generating unit main body that generates vibrations and a shaft that connects the generating unit main body and the container, and it is preferable that the generating unit main body is located outside the vacuum chamber.

[0050] By disposing the vibration generating unit body outside the vacuum chamber as in this embodiment, deterioration in the quality of the film formed on the powder can be suppressed.

[0051] The powder film formation method according to the present disclosure is a method of performing a film formation process on a surface of powder using the powder film formation apparatus, and includes the steps of placing powder in the container, transporting the powder in the container along the upward transport path, causing the powder transported upward to fall onto the bottom surface through the powder drop space, and forming a film on the surface of the powder using the film formation material that has become ready for film formation.

[0052] In this method, the powder is efficiently stirred in a container for carrying out a film-forming treatment on the surface of the powder, whereby a film can be efficiently formed on the surface of the powder. Effect of the Invention

[0053] According to the present disclosure, a powder film formation apparatus and a powder film formation method are provided that can efficiently form a film on the surface of powder by efficiently stirring the powder in a container for performing a film formation process on the powder. [Brief description of the drawings]

[0054] [Figure 1] 1 is a side view showing a powder film forming apparatus according to a first embodiment, with a portion thereof depicted in cross section. [Diagram 2] FIG. 2 is a perspective view showing a container and a powder moving mechanism in the main body of the powder film forming apparatus according to the first embodiment. [Diagram 3] 1 is a schematic diagram showing a chamber body and a lid of a vacuum chamber of a powder film formation apparatus according to a first embodiment. [Figure 4] 2 is a schematic plan view for explaining the positional relationship between a cathode, a bottom surface of a container, and an upper transport path of the powder film forming apparatus according to the first embodiment. FIG. [Diagram 5] 1 is a schematic cross-sectional view showing a powder film forming apparatus according to a first embodiment. [Figure 6] FIG. 11 is a schematic cross-sectional view showing a powder film forming apparatus according to a second embodiment. [Figure 7] FIG. 11 is a schematic cross-sectional view showing a powder film forming apparatus according to a third embodiment. [Figure 8] 13 is a schematic plan view for explaining the positional relationship between an opening in a plasma source of a powder film formation apparatus according to a third embodiment, a bottom surface of a container, a pipe of a raw material gas supply unit, and an upper transfer path. FIG. [Figure 9] FIG. 2 is a side view showing a powder film forming apparatus according to a first modified example of the first embodiment, with a part drawn in cross section. [Figure 10] 10 is a cross-sectional view taken along line XX in FIG. 9. [Figure 11] FIG. 11 is a side view showing a powder film forming apparatus according to a second modified example of the first embodiment, with a part drawn in cross section. [Figure 12] 12 is a cross-sectional view taken along line XII-XII in FIG. 11. [Figure 13] FIG. 11 is a side view showing a powder film forming apparatus according to a third modified example of the first embodiment, with a part drawn in cross section. [Figure 14] 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13. [Figure 15]FIG. 11 is a side view showing a powder film forming apparatus according to a fourth modified example of the first embodiment, with a part drawn in cross section. [Figure 16] FIG. 11 is a side view showing a powder film forming apparatus according to a fifth modified example of the first embodiment, with a part drawn in cross section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] Hereinafter, a powder film forming apparatus and a powder film forming method according to an embodiment of the present disclosure will be described with reference to the drawings. The powder film forming apparatus according to the present embodiment is an apparatus for forming a film on a surface of powder by a film forming method such as PVD (physical vapor deposition) or CVD (chemical vapor deposition). Specifically, examples of PVD include sputtering and arc ion plating. Examples of CVD include plasma CVD.

[0056] [First embodiment] FIG. 1 is a side view of a powder film formation apparatus 1 according to a first embodiment, partially drawn in cross section. FIG. 2 is a perspective view showing a container and a powder moving mechanism of the powder film formation apparatus 1. FIG. 3 is a schematic diagram showing a chamber body and a lid of a vacuum chamber of the powder film formation apparatus 1. FIG. 4 is a schematic plan view for explaining the positional relationship between the cathode of the powder film formation apparatus 1, the bottom surface of the container, and the upper transport path. FIG. 5 is a schematic cross-sectional view showing the powder film formation apparatus 1.

[0057] The powder film forming apparatus 1 according to the first embodiment is an apparatus that performs a film forming process on the surface of powder by sputtering.

[0058] 1 to 5, the powder film forming apparatus 1 includes an apparatus main body, a vacuum chamber 40, a sputtering unit 50, an inert gas supply unit 70 (see FIG. 5), and a support table 90 that supports these. The apparatus main body includes a container 10 and a powder moving mechanism 30.

[0059] The container 10 is a cylindrical container having a bottom and a side wall. The container 10 has an upwardly open shape. The container 10 has a bottom surface 13 which is the upper surface of the bottom, and an inner surface 14 which is the inner surface of the side wall.

[0060] The bottom surface 13 is a surface on which the powder F to be supplied into the container 10 at the start of the film formation process can be placed. The bottom surface 13 includes an inclined surface. This inclined surface is inclined downward from the center of the bottom surface 13 (a portion through which the central axis A of the cylindrical container 10 passes) toward the outside in the radial direction of the container 10. In this embodiment, the inclined surface is continuously formed from the center of the bottom surface 13 to the outer periphery of the bottom surface 13. A powder drop space S is formed inside the container 10. This powder drop space S is a space for dropping the powder F toward the bottom surface 13 inside the container 10 when the film formation process is performed, and is a space that continues upward from the bottom surface 13. Details of the powder drop space S will be described later.

[0061] The inner surface 14 has a circular shape in a plan view, and is a surface that rises upward from the outer periphery of the bottom surface 13. A spiral conveying path 31A, which will be described later, is attached to this inner surface 14.

[0062] The powder moving mechanism 30 is configured to transport the powder F arranged on the bottom surface 13 upward and cause the transported powder F to fall onto the bottom surface 13 through the powder falling space S. The powder moving mechanism 30 has an upward transport path 31 and a vibration generating unit 32 (vibration generating device).

[0063] The upper conveying path 31 is formed in an area inside the container 10 other than the powder falling space S, and is a path along which the powder F is conveyed. The upper conveying path 31 includes a spiral conveying path 31A and an inner guide path 31B. In this embodiment, the upper conveying path 31 is a separate component from the container 10, but may be a component that constitutes a part of the container 10 as in Modification 3 described later.

[0064] As shown in FIG. 2, FIG. 4 and FIG. 5, the spiral conveying path 31A extends upward from the bottom surface 13 in a spiral shape along the inner surface 14 of the container 10. The lower end of the spiral conveying path 31A is disposed at a position adjacent to the outer periphery of the bottom surface 13, and the upper end of the spiral conveying path 31A is disposed at a position adjacent to the inner surface 14 above the bottom surface 13. Specifically, the upper end of the spiral conveying path 31A is provided at a position adjacent to the inner surface 14 at the upper portion of the container 10 (near the upper end of the container 10). The spiral conveying path 31A has an upper surface on which the powder F is disposed. The outer edge (the radially outer edge) of the upper surface of the spiral conveying path 31A is connected to the inner surface 14 of the container 10. The spiral conveying path 31A has a gradient such that the position becomes higher from the lower end to the upper end.

[0065] The inner guide path 31B extends from the upper end of the spiral conveying path 31A so as to guide the powder F conveyed to the upper end of the spiral conveying path 31A to a region radially inward of the upper end of the container 10. As shown in FIG. 2, the inner guide path 31B has an upper surface on which the powder F is placed, and a pair of side surfaces rising upward from a pair of edges located on both sides of the upper surface. The inner guide path 31B is disposed so that the drop point of at least a part of the powder F dropping from the tip of the inner guide path 31B is the center of the bottom surface 13. Specifically, as shown in FIG. 4, the tip of the inner guide path 31B is located near the central axis A of the container 10 in a plan view. The inner guide path 31B has a curved shape (for example, a circular arc shape) in a plan view, but may include a part extending linearly.

[0066] The vibration generating unit 32 operates to vibrate the container 10 to transport the powder F placed on the bottom surface 13 upward along the spiral conveying path 31A, and also to guide the powder F that reaches the upper end of the spiral conveying path 31A along the inner guide path 31B to the tip of the inner guide path 31B.

[0067] The vibration generating unit 32 includes a generating unit main body 321 and a shaft 322. The shaft 322 interconnects the generating unit main body 321 and the container 10. An upper portion of the shaft 322 is connected to a bottom portion of the container 10. This allows the generating unit main body 321 to transmit vibrations to the container 10 via the shaft 322, thereby vibrating the container 10.

[0068] The vibration generating unit 32 is configured to be able to vibrate the container 10 in a direction including a component in the direction of the central axis A of the container 10 (vertical direction) and a component in the circumferential direction around the central axis A. Specifically, the vibration generating unit 32 may vibrate the container 10 so that the container 10 reciprocates in a first direction including a component in one circumferential direction and an upward component, and a second direction including a component in the other circumferential direction and a downward component. The vibration generating unit 32 may also vibrate the container 10 so that the container 10 alternately moves in a direction including a component in one circumferential direction and an upward component, and a direction including a component in one circumferential direction and a downward component. By vibrating the container 10 in a direction including such components, the powder F can be efficiently transported upward along the spiral transport path 31A as shown by the arrow in FIG. 2, and efficiently guided radially inward along the inner guide path 31B. The powder F that has reached the tip of the inner guide path 31B falls toward the bottom surface 13 in the powder falling space S.

[0069] As described above, the powder drop space S is a space for dropping the powder F toward the bottom surface 13 in the container 10. In this embodiment, the powder drop space S is a space radially inward of the container 10 from the spiral conveying path 31A. Specifically, the powder drop space S is a space radially inward of the container 10 from the spiral conveying path 31A, and is a space below the downstream end of the upper conveying path 31 in the conveying direction. In this embodiment, the downstream end of the upper conveying path 31 in the conveying direction is the end of the inner guide path 31B. This powder drop space S is a space that is continuous in the vertical direction from the bottom surface 13 to the end of the upper conveying path 31 (the end of the inner guide path 31B).

[0070] The vacuum chamber 40 forms an internal space that accommodates the container 10. The vacuum chamber 40 has a chamber body 41 and a lid 42. The chamber body 41 is, for example, a cylindrical container having a bottom. The chamber body 41 has a shape that opens upward. The lid 42 can open and close an opening at the top of the chamber body 41. As shown in FIG. 3, the lid 42 is attached to the top of the chamber body 41 via a hinge 43 so as to be able to open and close. A pipe 411 for drawing a vacuum is connected to the side of the chamber body 41. An unillustrated end of the pipe 411 is connected to a pump for drawing a vacuum.

[0071] 1, the lid 42 has a disk-shaped lid body 421 and an attachment part 422 provided in the center of the lid body 421. The attachment part 422 is a part to which a target 52, which will be described later, is detachably attached. When the lid 42 closes the upper opening of the chamber body 41 with the target 52 attached to the attachment part 422, the target 52 is disposed above the vessel 10 in the vacuum chamber 40. Specifically, in this state, the target 52 is positioned so as to face the bottom surface 13 of the vessel 10 in the vertical direction with a gap therebetween. Thus, the vacuum chamber 40 accommodates the vessel 10 and the target 52 in its internal space.

[0072] The sputtering unit 50 includes the above-mentioned target 52 and various components such as a cooling mechanism housed in a case 51. In a powder film forming apparatus 1 that performs a film forming process on a surface of a powder by sputtering, the target 52 forms a cathode or a part of the cathode. The container 10 or the vacuum chamber 40 may form an anode. When the powder film forming apparatus 1 is an apparatus that performs a film forming process on a surface of a powder by, for example, magnetron sputtering, the sputtering unit 50 includes a magnet. In this case, the magnet is disposed adjacent to the target 52 (for example, directly above the target 52).

[0073] The inert gas supply unit 70 is for supplying an inert gas into the vacuum chamber 40 when a film forming process is performed (see FIG. 5). The inert gas from the inert gas supply unit 70 may be supplied into the vacuum chamber 40 through, for example, the same piping as the evacuation piping 411 connected to the pump, or may be supplied into the vacuum chamber 40 through a supply piping (not shown) provided separately from the evacuation piping 411. As the inert gas, for example, argon gas is used.

[0074] Next, a method of performing a film formation process on the surface of the powder F by sputtering will be described. First, with the lid 42 open to the chamber body 41, the target 52 is attached to the lid 42 of the vacuum chamber 40, and a predetermined amount of the powder F is placed on the bottom surface 13 of the container 10. After that, the lid 42 is closed so as to cover the upper opening of the chamber body 41. Next, after the vacuum chamber 40 is evacuated, an inert gas (e.g., argon gas) is supplied into the vacuum chamber 40. In this state, a glow discharge occurs when an external power source (e.g., a direct current power source) not shown applies positive and negative voltages to the anode and the target 52 (cathode), respectively, and a plasma region P is generated near the target, and the inert gas is ionized. The ionized inert gas collides with the target 52, and particles E (e.g., atoms or molecules) constituting the target 52 are knocked out by the kinetic energy. A part of the particles E knocked out from the target 52 moves downward in the powder drop space S and adheres to the surface of the powder F on the bottom surface 13. In this embodiment, as shown in FIG. 2 and FIG. 5, there is no obstruction between at least a part of the spiral transport path 31A and the lower surface of the target 52, which is the position where the film forming material is in a film forming state. Therefore, another part of the particles E knocked out from the target 52 moves toward the at least a part of the spiral transport path 31A in the powder drop space S and adheres to the surface of the powder F thereon. This allows the film forming process to be performed on the surface of the powder F on the bottom surface 13 and the surface of the powder F on the at least a part of the spiral transport path 31A. The inert gas also has a function (action) of maintaining the plasma state in the plasma region P.

[0075] In this embodiment, the target 52 constituting the cathode, the anode, and the inert gas supply unit 70 are an example of a film formation source that makes the film formation material in a film-formable state capable of forming a film on the surface of the powder F. Specifically, the target 52, the anode, and the inert gas supply unit 70 make the film formation material in the film-formable state on the lower surface of the target 52, and supply the film formation material E in the film-formable state to the powder F on the bottom surface 13 through the powder drop space S. The material constituting the target 52 is an example of a film formation material, and the particles E knocked out from the target 52 (particles E flying out from the target 52) ​​are an example of a film formation material in a film-formable state. The position of the lower surface of the target 52 is an example of a position facing the bottom surface 13 in the vertical direction through the powder drop space S. The position of the lower surface of the target 52 is also an example of a position facing the bottom surface 13 in the vertical direction above the container 10. In addition, the lower surface of the target 52 may be located within the container 10. In this case, the target 52 as the film-forming source, the anode, and the inert gas supply unit 70 are configured to bring the film-forming material to the film-forming state on the lower surface of the target 52 located within the container 10, and to supply the film-forming material in the film-forming state to the powder on the bottom surface 13.

[0076] As described above, in the powder film forming apparatus 1 and the powder film forming method according to the first embodiment, the target 52 is disposed so as to face the bottom surface 13 in the vertical direction through the powder drop space S, so that the film forming source including the target 52 can put the film forming material into a film-forming state at a position facing the bottom surface 13 in the vertical direction through the powder drop space S. The film forming material E that has been put into a film-forming state by the film forming source can move toward the bottom surface 13 in the vertical direction or in a direction inclined thereto through the powder drop space S. Therefore, the film forming material E that has been put into a film-forming state above the bottom surface 13 can directly act on the powder F on the bottom surface 13, and can efficiently contact the surface of the powder F on the bottom surface 13. In addition, in this embodiment, the film forming material E that has been put into a film-forming state can also contact the surface of the powder F on at least a part of the spiral conveying path 31A, and can also contact the surface of the powder F on the inner guide path 31B. Moreover, since the upper conveying path 31 of the powder moving mechanism 30 is formed in an area other than the powder drop space S within the container 10, it does not interfere with the movement of the powder F falling toward the bottom surface 13 through the powder drop space S, and does not interfere with the movement of the film forming material E in a film-formable state that is supplied to the powder F on the bottom surface 13 through the powder drop space S. Therefore, this powder film forming apparatus 1 conveys the powder F upward, and returns the conveyed powder F to the bottom surface 13 through the powder drop space S to form a series of smooth flows of the powder F, thereby reliably circulating the powder F, and efficiently agitating the powder F while efficiently bringing the film forming material E in a film-formable state into contact with the powder F on the bottom surface 13, thereby efficiently forming a film on the surface of the powder F. Note that, until the film forming operation of the powder film forming apparatus 1 is stopped, the series of movements of the powder F, in which the powder F is conveyed upward from the bottom surface 13 and the conveyed powder F falls to the bottom surface 13, may be repeated multiple times.

[0077] Furthermore, in the first embodiment, the powder F arranged on the bottom surface 13 and the target 52 can be arranged to face each other in the vertical direction via the powder falling space S. This allows the particles E flying out from the target 52 to efficiently come into contact with the powder F arranged on the bottom surface 13 and the powder F falling in the powder falling space S. As a result, a film can be efficiently formed on the surface of the powder F.

[0078] In the first embodiment, as shown in FIG. 4, the area of ​​the bottom surface 13 overlapping the powder drop space S in a plan view has a size such that the target 52 is included within the range of the area in a plan view. In other words, the area of ​​the bottom surface 13 radially inward from the spiral transport path 31A in a plan view has a size such that the target 52 is included within the range of the area in a plan view. In a film formation process by sputtering, the particles E flying out from the target 52 constituting the cathode not only move downward parallel to the vertical direction from the target 52, but also move so as to diffuse diagonally downward inclined at a certain angle range with respect to the vertical direction. Therefore, by making the area of ​​the bottom surface 13 overlapping the powder drop space S in a plan view larger than the target 52, the particles E can be brought into contact with the powder F over a wider range on the bottom surface 13. As a result, a film can be formed on the surface of the powder F more efficiently.

[0079] Moreover, by forming the spiral conveying path 31A for conveying the powder F upward in a spiral shape along the inner surface 14 of the container 10, the powder falling space S can be formed in an area inside the spiral conveying path 31A, i.e., an area near the center of the container 10 (an area including the central axis A of the cylindrical container 10). Therefore, the spiral conveying path 31A can be provided in the radially outer area of ​​the container 10, which does not interfere with the powder F falling toward the bottom surface 13 through the powder falling space S and the film forming material E in a film-formable state moving toward the bottom surface through the powder falling space S, and the powder F on the bottom surface 13 can be conveyed upward along the spiral conveying path 31A by the vibration of the container 10.

[0080] Since the upper conveying path 31 further includes an inner guide path 31B extending from the upper end of the spiral conveying path 31A so as to be able to guide the powder F conveyed to the upper end of the spiral conveying path 31A to a region radially inward from the upper end, the powder F conveyed to the upper end of the spiral conveying path 31A can be further guided to a radially inner region by the inner guide path 31B. This allows the drop point on the bottom surface 13 of the powder F dropping from the tip of the inner guide path 31B to be closer to the center of the bottom surface 13.

[0081] Then, the powder F that falls from the tip of the inner guide path 31B and reaches the center of the bottom surface 13 is efficiently moved radially outward along the inclined surface of the bottom surface 13 by the vibration of the container 10. This effectively forms a flow of the powder F in which the powder F moves from the center of the bottom surface 13 to the radially outward and reaches the entrance of the spiral conveying path 31A. As a result, the powder F is prevented from being locally retained on the bottom surface 13, and the agitation of the powder F is further promoted.

[0082] Furthermore, the inner guide path 31B may include a portion that slopes downward toward the tip of the inner guide path 31B. In this case, the distance between the tip of the inner guide path 31B and the center of the bottom surface 13 can be made smaller. This prevents the powder F from scattering to the surroundings before the powder F falls from the tip of the inner guide path 31B and reaches the bottom surface 13, making it easier to move the drop point of the powder F on the bottom surface 13 closer to the center of the bottom surface 13. Only a portion of the inner guide path 31B may slope downward, or the entire inner guide path 31B may slope downward.

[0083] The vacuum chamber 40 has an internal space for accommodating the container 10, a chamber body 41 that opens upward, and a lid portion 42 that is attached to the upper part of the chamber body 41 in an openable and closable manner, and the target 52 is attached to the lid portion 42 in a detachable manner. Therefore, the film formation process can be performed with the lid portion 42 closing the upper part of the chamber body 41, and the target 52 can be easily replaced with the lid portion 42 open. As described above, the present embodiment employs a configuration in which the vibration generating portion 32 vibrates the container 10 to transport the powder F arranged on the bottom surface 13 upward along the upper transport path 31, and the transported powder F falls to the bottom surface 13 through the powder falling space S. This makes it unnecessary to have a rotary sliding portion that rotatably supports the rotary barrel-type sputtering chamber of Patent Document 1, for example, and therefore simplifies the mechanism for creating a vacuum in the vacuum chamber 40.

[0084] [Second embodiment] FIG. 6 is a schematic cross-sectional view showing a powder film forming apparatus 1 according to the second embodiment.

[0085] The powder film forming apparatus 1 according to the second embodiment is an apparatus that performs film forming processing on the surface of powder by arc ion plating.

[0086] The powder film forming apparatus 1 according to the second embodiment includes an apparatus main body, a vacuum chamber 40, an ion plating unit 50A, and a support table 90 that supports these. The apparatus main body includes a container 10 and a powder moving mechanism 30.

[0087] The configurations of the container 10, powder moving mechanism 30, vacuum chamber 40 and support stage 90 of the powder film formation apparatus 1 according to the second embodiment are similar to those of the powder film formation apparatus 1 according to the first embodiment shown in Figures 1 to 5, and therefore illustration and description of these will be omitted. Below, differences between the powder film formation apparatus 1 according to the second embodiment and the first embodiment will be mainly described.

[0088] The ion plating unit 50A includes a target 52 and various components such as a magnet and a cooling mechanism housed in a case 51A. In the powder film forming apparatus 1 that performs a film forming process on the surface of the powder F by arc ion plating, the target 52 constitutes a cathode or a part of the cathode. The anode may be constituted by a container 10. In this case, the cooling mechanism may have a pipe for cooling water wound around the outer periphery of the container 10. The container 10 is cooled by supplying cooling water to this pipe.

[0089] In the film formation process by arc ion plating, a solid target 52 is evaporated using a vacuum arc discharge. Specifically, in this film formation process, in a vacuum atmosphere, the target 52 is used as a cathode, and electric power is supplied from an external power source (not shown) to generate a vacuum arc discharge between the target 52 and an anode. This causes the film formation material constituting the target 52 to evaporate from the surface of the target 52 and become ionized. The ionized film formation material E is supplied to the powder F on the bottom surface 13, and thus a film is formed on the surface of the powder F.

[0090] In this second embodiment, the target 52 constituting the cathode and the anode are an example of a film forming source that makes the film forming material in a film-formable state capable of forming a film on the surface of the powder F. Specifically, the target 52 and the anode make the film forming material in the film-formable state on the lower surface of the target 52, and supply the film forming material in the film-formable state to the powder F on the bottom surface 13 through the powder falling space S. The material constituting the target 52 is an example of a film forming material, and the film forming material E evaporated from the surface of the target 52 and ionized is an example of a film forming material in a film-formable state. The position of the lower surface of the target 52 is an example of a position facing the bottom surface 13 in the vertical direction through the powder falling space S. The position of the lower surface of the target 52 is also an example of a position facing the bottom surface 13 in the vertical direction above the container 10. The lower surface of the target 52 may be located inside the container 10.

[0091] As in the first embodiment, the powder film forming apparatus 1 of the second embodiment transports the powder F upward and returns the transported powder F to the bottom surface 13 through the powder falling space S, thereby forming a series of flows of powder F to efficiently stir the powder F, while efficiently bringing the film forming material E in a state ready for film formation into contact with the powder F on the bottom surface 13, thereby efficiently forming a film on the surface of the powder F.

[0092] In the second embodiment, the powder F and the target 52 disposed on the bottom surface 13 can be opposed to each other in the vertical direction through the powder drop space S. Therefore, the film forming source including the target 52 can make the film forming material in a film forming state at a position facing the bottom surface 13 in the vertical direction through the powder drop space S. This allows the ions evaporated from the target 52 to efficiently contact the powder F disposed on the bottom surface 13 and the powder F falling through the powder drop space S. As a result, a film can be efficiently formed on the surface of the powder F. In the second embodiment, similarly to the first embodiment, the film forming material E in the film forming state can also contact the surface of the powder F on at least a part of the spiral conveying path 31A, and can also contact the surface of the powder F on the inner guide path 31B. As a result, the film forming process is not only performed on the powder F on the bottom surface 13, but also on the powder F on at least a part of the spiral conveying path 31A and the powder F on the inner guide path 31B.

[0093] [Third embodiment] FIG. 7 is a schematic cross-sectional view showing a powder film forming apparatus 1 according to the third embodiment.

[0094] The powder film-forming apparatus 1 according to the third embodiment is an apparatus that performs a film-forming process on the surface of the powder F by plasma CVD.

[0095] The powder film forming apparatus 1 according to the third embodiment includes an apparatus main body, a vacuum chamber 40, a plasma source 60, a raw material gas supply unit, an inert gas supply unit 70, and a support table 90 that supports these components. The apparatus main body includes a container 10 and a powder moving mechanism 30.

[0096] The configurations of the container 10, powder moving mechanism 30, vacuum chamber 40 and support stage 90 of the powder film formation apparatus 1 according to the third embodiment are similar to those of the powder film formation apparatus 1 according to the first embodiment shown in Figures 1 to 5, and therefore illustration and description of these will be omitted. Below, differences between the powder film formation apparatus 1 according to the third embodiment and the first embodiment will be mainly described.

[0097] The plasma source 60 has a function of making the source gas in the vacuum chamber 40 into a state in which a film can be formed. The plasma source 60 includes a case 61, a power supply housed in the case 61, and an electrode or a coil. The power supply may be placed outside the plasma source 60.

[0098] The raw material gas supply unit supplies raw material gas as a film forming material into the vacuum chamber 40. In the specific example shown in FIG. 7, the raw material gas supply unit has a pipe 62 for supplying raw material gas. The pipe 62 supplies raw material gas to an area affected by the action of the plasma source 60. Specifically, as shown in FIG. 7, the pipe 62 has a plurality of gas supply holes on the lower surface of the pipe 62, and is configured so that the raw material gas can be supplied from these gas supply holes to the lower side of the plasma source 60. When the pipe 62 has an annular shape in a plan view, the plurality of gas supply holes are provided, for example, on the lower surface of the pipe 62 at intervals along the circumferential direction. It is preferable that the plurality of gas supply holes are provided evenly in the circumferential direction. In this case, unevenness in the film forming process can be reduced compared to when the pipe is, for example, a straight pipe.

[0099] The raw material gas supplied from the pipe 62 of the raw material gas supply unit is in a state in which a film can be formed in an area affected by the plasma source 60, for example, an area directly below the plasma source 60, such as an area P surrounded by a two-dot chain line P in FIG. 7. The raw material gas E in a state in which a film can be formed is supplied to the powder F on the bottom surface 13. As a result, a film is formed on the surface of the powder F.

[0100] Specifically, an opening 63 is provided at the bottom of the plasma source 60. This opening 63 is for discharging plasma generated inside the plasma source 60 to the outside. When plasma is discharged from the opening 63 of the plasma source 60, a plasma region P is formed directly below the plasma source 60. The raw material gas supplied from the pipe 62 of the raw material gas supply unit is decomposed in the plasma region P to become in a state in which a film can be formed. That is, in this embodiment, the raw material gas E in a state in which a film can be formed is a product (decomposition product) generated by decomposing the raw material gas by the plasma discharged from the plasma source 60.

[0101] In the third embodiment, the plasma source 60 and the raw material gas supply unit are an example of a film forming source that makes the raw material gas as a film forming material in a film-forming state capable of forming a film on the surface of the powder F. Specifically, the plasma source 60 and the raw material gas supply unit make the film forming material in the film-forming state in the plasma region P where the action of the plasma source 60 is applied, and supply the film forming material E in the film-forming state to the powder F on the bottom surface 13 through the powder falling space S. The raw material gas supplied by the raw material gas supply unit is an example of a film forming material. A product generated by decomposing the raw material gas by the plasma emitted from the plasma source 60 is an example of a film forming material in a film-forming state. The plasma region P where the action of the plasma source 60 is applied is located opposite the bottom surface 13 in the vertical direction. As shown in FIG. 7, the lower part of the plasma region P may be located in the powder falling space S in the container 10. The upper part of the plasma region P is located between the container 10 and the plasma source 60, and may be located at a position facing the bottom surface 13 in the vertical direction with the powder falling space S interposed therebetween.

[0102] Although not shown, the upper part of the plasma region P may be located inside the container 10. Specifically, for example, the opening 63 of the plasma source 60 or its vicinity may be located near the upper end of the container 10 or inside the container 10. In this case, since the upper part of the plasma region P located immediately below the opening 63 is located inside the container 10, the plasma region P can be brought closer to the bottom surface 13 as a whole. Here, the plasma emitted from the opening 63 of the plasma source 60 not only moves downward parallel to the vertical direction from the opening 63, but also moves so as to diffuse diagonally downward inclined at a certain angle range with respect to the vertical direction. Therefore, if the plasma region P can be brought closer to the bottom surface 13, the proportion of the plasma emitted from the opening 63 that moves toward, for example, the inner surface 14 of the container 10 can be reduced, and the proportion of the plasma that moves toward the bottom surface 13 can be increased. This allows the powder on the bottom surface 13 to be more efficiently film-formed.

[0103] As in the first embodiment, the powder film forming apparatus 1 of the third embodiment transports the powder F upward and returns the transported powder F to the bottom surface 13 through the powder falling space S, thereby forming a series of flows of powder F to efficiently stir the powder F, while efficiently bringing the film forming material E in a state ready for film formation into contact with the powder F on the bottom surface 13, thereby efficiently forming a film on the surface of the powder F.

[0104] In the third embodiment, the powder F arranged on the bottom surface 13 and the plasma source 60 are opposed to each other in the vertical direction through the powder drop space S. Therefore, the film forming source including the plasma source 60 and the raw material gas supply unit can make the raw material gas as the film forming material in a film forming state at a position facing the bottom surface 13 in the vertical direction through the powder drop space S and in a part of the powder drop space S. This allows the raw material gas E in a film forming state by the plasma source 60 to efficiently contact the powder F arranged on the bottom surface 13 and the powder F falling through the powder drop space S. As a result, a film can be efficiently formed on the surface of the powder F. In addition, in the third embodiment, as in the first embodiment, the film forming material E in a film forming state can also contact the surface of the powder F on at least a part of the spiral conveying path 31A, and can also contact the surface of the powder F on the inner guide path 31B. As a result, the film forming process is performed not only on the powder F on the bottom surface 13, but also on the powder F on at least a portion of the spiral conveying path 31A and the powder F on the inner guide path 31B.

[0105] FIG. 8 is a schematic plan view for explaining the positional relationship between an opening 63 in a plasma source 60 of the powder film forming apparatus 1, a bottom surface 13 of a container 10, a pipe 62 of a raw material gas supply unit, and an upper transfer path 31.

[0106] The opening 63 of the plasma source 60 is formed, for example, in the bottom surface 64 of the case 61. By providing this opening 63 in the bottom surface 64 of the case 61, the action of the plasma source 60 can be more effectively exerted through the opening 63 on the raw material gas supplied below the plasma source 60.

[0107] In the powder deposition apparatus 1, a pipe 62 of a raw material gas supply unit is arranged in an annular shape so as to surround a plasma source 60 (more specifically, an opening 63 of the plasma source 60) in the plan view shown in Fig. 8. The raw material gas is supplied below the plasma source 60 from a plurality of gas supply holes formed in the pipe 62.

[0108] In this manner, the pipe 62 of the raw material gas supply section is disposed so as to surround the opening 63 of the plasma source 60 in a plan view, and therefore the pipe 62 does not impede the downward movement of the plasma emitted from the opening 63. This allows the raw material gas supplied below the plasma source 60 from the gas supply hole of the pipe 62 to come into contact with the plasma emitted from the opening 63 of the plasma source 60 efficiently.

[0109] In the specific example shown in Fig. 8, the outer diameter of the annular pipe 62 is smaller than the opening diameter of the container 10 (the inner diameter of the container 10), and the pipe 62 is arranged so as to be contained within the range of the container 10 in a plan view. However, the pipe 62 is not limited to the aspect shown in Fig. 8. The outer diameter of the pipe 62 may be larger than the opening diameter of the container 10, for example. Specifically, the pipe 62 may be arranged so that the container 10 is contained within the inner region of the annular pipe 62 in a plan view, for example.

[0110] As shown in FIG. 8, the area of ​​the bottom surface 13 that overlaps with the powder drop space S in plan view is large enough to include the opening 63 provided on the lower surface 64 of the plasma source 60. In other words, the area of ​​the bottom surface 13 that is radially inward of the spiral conveying path 31A in plan view is large enough to include the opening 63 of the plasma source 60 within the range of the area in plan view. In FIG. 8, the area occupied by the powder drop space S in plan view (i.e., the area of ​​the bottom surface 13 that overlaps with the powder drop space S in plan view) is shown by a number of dots so that it is easy to distinguish. Note that the area also exists at a position corresponding to the pipe 62 and the inner guide path 31B in plan view, but dots are not added to the positions corresponding to the pipe 62 and the inner guide path 31B.

[0111] In the film formation process by plasma CVD, the source gas E that has been made into a film-formable state by the plasma source 60 not only moves downward parallel to the vertical direction from directly below the opening 63 of the plasma source 60, but also moves so as to diffuse diagonally downward inclined at a certain angle range with respect to the vertical direction. Therefore, by making the area of ​​the bottom surface 13 that overlaps with the powder drop space S in a plan view larger than the opening 63 provided on the lower surface 64 of the plasma source 60, the source gas E that has been made into a film-formable state can be brought into contact with the powder F over a wider area of ​​the bottom surface 13. As a result, a film can be formed on the surface of the powder F more efficiently.

[0112] 7 supplies an inert gas into the container 10 so that the source gas E that has become capable of film formation below the plasma source 60 is guided toward the bottom surface 13 in the powder falling space S. As a result, the source gas E that has become capable of film formation is guided toward the bottom surface 13 by the inert gas supplied from the inert gas supply unit 70, so that a film can be formed more efficiently on the surface of the powder F. The supplied inert gas also has a function (action) of maintaining the plasma state.

[0113] [Modifications 1 to 3 of the first embodiment] Next, a description will be given of Modifications 1 to 3 of the first embodiment. Each of the powder film forming apparatuses 1 according to Modifications 1 to 3 of the first embodiment is an apparatus that performs a film forming process on the surface of powder by sputtering.

[0114] Fig. 9 is a side view of a powder film forming apparatus 1 according to Modification 1 of the first embodiment, partially drawn in cross section. Fig. 10 is a cross-sectional view taken along line XX in Fig. 9. As shown in Figs. 9 and 10, the powder film forming apparatus 1 according to Modification 1 includes an apparatus main body, a vacuum chamber 40, a sputtering unit 50, an inert gas supply unit 70, and a support table 90 that supports these. The apparatus main body includes a container 10 and a powder moving mechanism 30.

[0115] The configurations of the container 10, vacuum chamber 40, inert gas supply unit 70, and support stand 90 of the powder film formation apparatus 1 according to the modified example 1 are similar to those of the powder film formation apparatus 1 shown in Figures 1 to 5, so detailed description thereof will be omitted. The following mainly describes the differences between the powder film formation apparatus 1 according to the modified example 1 and the powder film formation apparatus 1 shown in Figures 1 to 5.

[0116] In the first modification, a first powder drop space S1 and a second powder drop space S2 are formed in the container 10. Each of these powder drop spaces S1 and S2 is a space for dropping the powder F toward the bottom surface 13 in the container 10 when the film forming process is performed, and is a space that continues upward from the bottom surface 13. The first powder drop space S1 and the second powder drop space S2 are provided so as to be located apart from each other in the circumferential direction in the container 10. Each of the first powder drop space S1 and the second powder drop space S2 is a space located radially inward of the spiral conveying path 31A in the container 10. In the specific example shown in FIG. 10, the first powder drop space S1 and the second powder drop space S2 are provided so as to be located radially opposite each other in the container 10.

[0117] 9 and 10, the sputtering unit 50 in the first modification includes a plurality of rotary cathodes 53 (specifically, four rotary cathodes 53). Each of the plurality of rotary cathodes 53 includes a cylindrical target 54 and a magnet 56 disposed within the target 54.

[0118] Each target 54 is supported by a support member (not shown) in such a position that the central axis of a cylinder constituting the target 54 faces in the vertical direction, so as to be rotatable around the central axis. At least the lower part of each target 54 is disposed within the container 10. The lower end of each target 54 is located below the center of the container 10 in the vertical direction, and the upper end of each target 54 is located above the center of the container 10 in the vertical direction. A coolant such as cooling water is supplied into the target 54.

[0119] Each magnet 56 has a shape extending along the direction of the central axis of the target 54 within the corresponding target 54. The magnets 56 form a magnetic field for increasing the density of plasma. The magnets 56 do not rotate together with the target 54, but are fixed to a predetermined position as shown in FIG. 10 by a fixing member (not shown). At least the lower part of each magnet 56 is disposed within the vessel 10. The lower end of each magnet 56 is located below the center of the vessel 10 in the vertical direction, and the upper end of each magnet 56 is located above the center of the vessel 10 in the vertical direction.

[0120] The four rotary cathodes 53 are arranged at intervals around the central axis A of the container 10 in the circumferential direction. Of the four rotary cathodes 53, two adjacent rotary cathodes 53 in the circumferential direction (the upper two rotary cathodes 53 in FIG. 10) are connected to an AC power supply PS as shown in FIG. 9. When a film formation process is performed, the AC power supply PS alternately applies positive and negative voltages for sputtering to the targets 54 of the two rotary cathodes 53. This causes a discharge between the two rotary cathodes 53 to form plasma. For example, in the specific example shown in FIG. 10, in each of the two rotary cathodes 53, the magnet 56 is arranged in a position closer to the first powder drop space S1 than the central axis of the cylinder constituting the target 54. This allows the two rotary cathodes 53 to locally form a first plasma region P1 at a position corresponding to the first powder drop space S1. The relative position of the magnet 56 with respect to the vessel 10 and the target 54 is set so that at least a portion of the plasma region formed by one rotary cathode 53 overlaps with at least a portion of the plasma region formed by the other rotary cathode 53 .

[0121] Similarly, the remaining two rotary cathodes 53 adjacent in the circumferential direction (the two lower rotary cathodes 53 in FIG. 10) are connected to an AC power source. When a film formation process is performed, the AC power source alternately applies positive and negative voltages for sputtering to the targets 54 of these two rotary cathodes 53. This causes discharge between the two rotary cathodes 53 to form plasma. For example, in the specific example shown in FIG. 10, in each of the two rotary cathodes 53, the magnet 56 is disposed in a position closer to the second powder drop space S2 than the central axis of the cylinder constituting the target 54. This allows the two rotary cathodes 53 to locally form a second plasma region P2 at a position corresponding to the second powder drop space S2. The relative positions of the magnet 56 with respect to the container 10 and the target 54 are set so that at least a part of the plasma region formed by one rotary cathode 53 and at least a part of the plasma region formed by the other rotary cathode 53 overlap.

[0122] The powder moving mechanism 30 is configured to transport the powder F arranged on the bottom surface 13 of the container 10 upward and drop the transported powder F onto the bottom surface 13 through the powder dropping space S. The powder moving mechanism 30 has an upward transport path 31 and a vibration generating unit 32.

[0123] The upper conveying path 31 is formed in an area inside the container 10 other than the powder falling space S, and is a path along which the powder F is conveyed. The upper conveying path 31 includes a spiral conveying path 31A and at least one guide wall (for example, two guide walls 311, 312 described below).

[0124] The spiral conveying path 31A in the first modification is similar to the spiral conveying path 31A shown in Figures 2, 4, and 5. That is, as shown in Figures 9 and 10, the spiral conveying path 31A extends spirally upward from the bottom surface 13 along the inner side surface 14 of the container 10. The spiral conveying path 31A has a gradient such that the position becomes higher from the lower end to the upper end.

[0125] The at least one guide wall is provided on the spiral conveying path 31A so as to guide the powder F conveyed upward along the spiral conveying path 31A to the inside (diametrically inside) of the spiral conveying path 31A and to allow the powder F to fall from the spiral conveying path 31A toward the bottom surface 13. In the specific example shown in FIG. 10, the at least one guide wall includes a first guide wall 311 provided on the upper part of the spiral conveying path 31A and a second guide wall 312 provided on the spiral conveying path 31A at a portion upstream in the conveying direction from the first guide wall 311. The first guide wall 311 and the second guide wall 312 are provided at positions corresponding to the first powder drop space S1 and the second powder drop space S2, respectively. The first guide wall 311 and the second guide wall 312 are provided at positions corresponding to the first plasma region P1 and the second plasma region P2, respectively, which will be described later. Specifically, the first guide wall 311 is provided at or near the upper end of the spiral conveying path 31A, and the second guide wall 312 is provided at a portion of the spiral conveying path 31A radially opposite the first guide wall 311 when viewed in a plane, as shown in Figure 10.

[0126] Each of the first guide wall 311 and the second guide wall 312 has a guide surface which is a side surface rising upward from the spiral conveying path 31A. The second guide wall 312 is disposed at a position radially inwardly spaced from the inner surface 14 of the container 10 so that a gap is formed between the second guide wall 312 and the inner surface 14 of the container 10. The guide surface of the second guide wall 312 has a shape capable of guiding a part of the powder F conveyed upward along the spiral conveying path 31A radially inward from the spiral conveying path 31A and allowing the powder F to fall from the spiral conveying path 31A toward the bottom surface 13 through the second powder falling space S2. The guide surface of the first guide wall 311 has a shape that enables the powder F, which passes through the gap between the second guide wall 312 and the inner surface 14 of the container 10 and is transported upward along the spiral conveying path 31A, to be guided radially inward from the spiral conveying path 31A and dropped from the spiral conveying path 31A toward the bottom surface 13 through the first powder drop space S1.

[0127] The vibration generating unit 32 in the first modification is the same as the vibration generating unit 32 shown in Figs. 1 and 2. That is, the vibration generating unit 32 operates to vibrate the container 10 to transport the powder F arranged on the bottom surface 13 upward along the spiral transport path 31A. The vacuum chamber 40 forms an internal space that houses the container 10. A pipe (not shown) for vacuum drawing is connected to the side of the chamber main body 41. The inert gas supply unit 70 is for supplying an inert gas into the vacuum chamber 40 when a film formation process is performed. For example, argon gas is used as the inert gas.

[0128] Next, in the first modification, a method of performing a film forming process on the surface of the powder F by sputtering will be described. First, a predetermined amount of the powder F is placed on the bottom surface 13 of the container 10, and after the vacuum chamber 40 is evacuated, an inert gas (e.g., argon gas) is supplied into the vacuum chamber 40. In this state, the AC power supply PS applies alternately positive and negative voltages to the targets 54 of the two rotary cathodes 53, thereby generating a first plasma region P1 near the targets 54 and ionizing the inert gas. Similarly, the AC power supply applies alternately positive and negative voltages to the targets 54 of the remaining two rotary cathodes 53, thereby generating a second plasma region P2 near the targets 54 and ionizing the inert gas. The ionized inert gas collides with the target 54, and the particles E (e.g., atoms or molecules) constituting the target 54 are knocked out by the kinetic energy.

[0129] A large number of particles E knocked out from the targets 54 of the four rotary cathodes 53 move in various directions within the container 10. Specifically, some of the particles E knocked out from the targets 54 move downward in the powder falling space S and adhere to the surface of the powder F on the bottom surface 13. Another part of the particles E knocked out from the targets 54 move toward the spiral transport path 31A and adhere to the surface of the powder F on the spiral transport path 31A. This makes it possible to perform a film formation process on the surface of the powder F on the bottom surface 13 and also on the surface of the powder F on the spiral transport path 31A.

[0130] In the first modification, each target 54 is disposed in such a manner that the central axis of the cylinder constituting the target 54 faces the vertical direction, and at least a part of the target 54 faces the spiral transport path 31A in the horizontal direction (the radial direction of the container 10). In the specific example shown in FIG. 9, each target 54 faces each of the multiple parts (multiple transport parts) in the spiral transport path 31A in the radial direction. The multiple transport parts are arranged vertically at intervals along the vertical direction, which is the longitudinal direction of the target 54. Therefore, the particles E knocked out from the target 54 are efficiently supplied to each of the multiple transport parts in the spiral transport path 31A and adhere to the surface of the powder F on the transport part. This allows the film formation process to be performed efficiently.

[0131] In addition, in the first modification, the multiple rotary cathodes 53 and the inert gas supply unit 70 are an example of a film formation source that makes the film formation material in a film-formable state in which a film can be formed on the surface of the powder F. Specifically, the multiple rotary cathodes 53 and the inert gas supply unit 70 are configured to make the film formation material in the film-formable state on the surface of the target 54 located in the container 10, and to supply the film formation material E in the film-formable state to the powder F on the bottom surface 13 through the powder drop space S and to supply the film formation material E to the powder F on the spiral transport path 31A. The material constituting the target 54 is an example of a film formation material, and the particles E knocked out from the target 54 (particles E flying out from the target 54) are an example of a film formation material in a film-formable state.

[0132] Fig. 11 is a side view of a powder film forming apparatus 1 according to Modification 2 of the first embodiment, partially drawn in cross section. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11. As shown in Figs. 11 and 12, the powder film forming apparatus 1 according to Modification 2 includes an apparatus main body, a vacuum chamber 40, a sputtering unit 50, an inert gas supply unit 70, and a support table 90 that supports these. The apparatus main body includes a container 10 and a powder moving mechanism 30.

[0133] The configurations of the container 10, powder moving mechanism 30, vacuum chamber 40, inert gas supply unit 70 and support stand 90 of the powder film formation apparatus 1 according to the modified example 2 are similar to those of the powder film formation apparatus 1 shown in Figures 1 to 5, so detailed description thereof will be omitted. The following mainly describes the differences between the powder film formation apparatus 1 according to the modified example 2 and the powder film formation apparatus 1 shown in Figures 1 to 5.

[0134] 11 and 12, the sputtering unit 50 in the second modification includes a plurality of rotary cathodes 53 (specifically, two rotary cathodes 53). Each of the plurality of rotary cathodes 53 has a similar configuration to the rotary cathode 53 in the first modification. That is, each of the plurality of rotary cathodes 53 includes a cylindrical target 54 and a magnet 56 disposed within the target 54.

[0135] In the second modification, each target 54 is supported by a support member (not shown) so as to be rotatable around the central axis of a cylinder constituting the target 54 with the central axis facing horizontally. The magnet 56 has a shape extending in the target 54 along the direction of the central axis of the target 54.

[0136] The two rotary cathodes 53 are disposed at a horizontal distance from each other above the bottom surface 13 of the container 10. Specifically, the two rotary cathodes 53 are arranged directly above the container 10 so as to face in the same direction and be disposed at the same height.

[0137] The two rotary cathodes 53 are connected to an AC power supply PS as shown in FIG. 11. When a film formation process is performed, the AC power supply PS alternately applies positive and negative voltages for sputtering to the targets 54 of the two rotary cathodes 53. This causes a discharge between the two rotary cathodes 53 to form plasma. In each of the two rotary cathodes 53, the magnet 56 is disposed at the bottom of the cylinder constituting the target 54 so that a plasma region P is formed in a wide range directly below the rotary cathodes 53. In each of the two rotary cathodes 53, the relative position of the magnet 56 with respect to the container 10 and the target 54 is set so that a plasma region P is formed between the rotary cathode 53 and the bottom surface 13 of the container 10.

[0138] As shown in Figure 12, the powder moving mechanism 30 in this variant example 2 has an upper conveying path 31 and a vibration generating unit 32 (vibration generating device), and the upper conveying path 31 includes a spiral conveying path 31A and an inner guide path 31B, similar to the upper conveying path 31 shown in Figures 2 and 4.

[0139] Next, in Modification 2, a method of performing a film forming process on the surface of the powder F by sputtering will be described. First, a predetermined amount of the powder F is placed on the bottom surface 13 of the container 10, and after the vacuum chamber 40 is evacuated, an inert gas (e.g., argon gas) is supplied into the vacuum chamber 40. In this state, the AC power source PS applies alternately positive and negative voltages to the targets 54 of the two rotary cathodes 53, thereby generating a plasma region P near these targets 54 and ionizing the inert gas. The ionized inert gas collides with the target 54, and particles E (e.g., atoms or molecules) constituting the target 54 are knocked out by the kinetic energy.

[0140] A part of the particles E knocked out from each of the targets 54 of the two rotary cathodes 53 moves downward in the powder drop space S and adheres to the surface of the powder F on the bottom surface 13. In this embodiment, as shown in FIG. 11, there is no obstruction between at least a part of the spiral transport path 31A and the lower surface of each target 54, which is the position where the film forming material is ready to be film-formed. Therefore, another part of the particles E knocked out from each target 54 moves toward the at least a part of the spiral transport path 31A in the powder drop space S and adheres to the surface of the powder F thereon. This allows the film formation process to be performed on the surface of the powder F on the bottom surface 13 and the surface of the powder F on the at least a part of the spiral transport path 31A.

[0141] In addition, in the second modification, the multiple rotary cathodes 53 and the inert gas supply unit 70 are an example of a film formation source that makes the film formation material in a film-formable state capable of forming a film on the surface of the powder F. Specifically, the multiple rotary cathodes 53 and the inert gas supply unit 70 make the film formation material in the film-formable state on the lower surface of the target 54, and supply the film formation material E in the film-formable state to the powder F on the bottom surface 13 through the powder drop space S and to the powder F on the spiral transport path 31A. The material constituting the target 54 is an example of a film formation material, and the particles E knocked out from the target 54 (particles E flying out from the target 54) are an example of a film formation material in a film-formable state. In addition, the position of the lower surface of the target 54 is an example of a position that is above the container 10 and faces the bottom surface 13 in the vertical direction. In addition, the underside of the target 54 may be located within the container 10. In this case, the multiple rotary cathodes 53 and the inert gas supply unit 70 as the film-forming source are configured to bring the film-forming material to the film-forming state on the underside of the target 54 located within the container 10, and supply the film-forming material in the film-forming state to the powder on the bottom surface 13.

[0142] Fig. 13 is a side view of a powder film forming apparatus 1 according to Modification 3 of the first embodiment, partially drawn in cross section. Fig. 14 is a cross-sectional view taken along line XIV-XIV in Fig. 13. As shown in Figs. 13 and 14, the powder film forming apparatus 1 according to Modification 3 includes an apparatus body, a vacuum chamber 40, a sputtering unit 50, an inert gas supply unit 70, and a support table 90 that supports these.

[0143] In this modified example 3, the device main body includes a container 10 and a vibration generating unit 32 (vibration generating device), the container 10 includes a bottom surface 13, an inner side surface 14, and an upper conveying path 31, the upper conveying path 31 including a spiral conveying path 31A and an inner guide path 31B. Also, in this modified example 3, the powder moving mechanism includes the upper conveying path 31 of the container 10 and the vibration generating unit 32. The upper conveying path 31 is formed in an area inside the container 10 other than the powder falling space S. In this modified example 3, the upper conveying path 31 constitutes a part of the container 10, specifically, constitutes a part of the inner surface of the container 10.

[0144] 13 and 14, the configuration of the container 10 is different from that of the modified example 2, and other configurations are the same as those of the modified example 2. In the following, the differences between the powder film formation apparatus 1 according to the modified example 3 and the powder film formation apparatus 1 according to the modified example 2 will be mainly described, and the description of the configurations similar to those of the modified example 2 will be omitted.

[0145] As shown in FIG. 13, the container 10 in variant example 3 is configured as a container (stepped bowl) having a shape in which the bottom surface 13, inner surface 14 and spiral conveying path 31A are arranged in a stepped manner in a cross section when the container 10 is cut along a vertical plane including the central axis A of the container 10.

[0146] The spiral conveying path 31A extends upward in a spiral shape from the bottom surface 13. The spiral conveying path 31A has a shape that gradually moves away from the center of the container 10 (the central axis A of the container 10) in a plan view as it goes upward. In other words, the spiral conveying path 31A has a shape that is positioned radially outward as it goes upward. The upper region 31A2 of the spiral conveying path 31A is positioned radially outward relative to the lower region 31A1 of the spiral conveying path 31A. Specifically, the spiral conveying path 31A has a shape such that the lower region 31A1 of the spiral conveying path 31A and the upper region 31A2 of the spiral conveying path 31A do not overlap in a plan view as shown in FIG. 14.

[0147] Compared to the spiral conveying path 31A in variant 2 (see Figures 11 and 12), which has a spiral shape such that the distance from the center (central axis A) of the container 10 is constant, the spiral conveying path 31A in variant 3 enables the film forming material that has reached a film-forming state to be efficiently supplied not only to the powder F in the upper region 31A2 of the spiral conveying path 31A, but also to the powder F in the lower region 31A1 of the spiral conveying path 31A.

[0148] Fig. 15 is a side view of the powder film formation apparatus 1 according to the fourth modified example of the first embodiment, partially drawn in cross section. Fig. 15 differs from Fig. 1 in that a sealing mechanism, which will be described later, is specifically illustrated. In the following, the configuration related to the sealing mechanism among the configuration of the powder film formation apparatus 1 shown in Fig. 15 will be mainly described, and the other configurations of the powder film formation apparatus 1 shown in Fig. 15 will be assigned the same reference numerals as in Fig. 1 and descriptions thereof will be omitted.

[0149] In the powder film forming apparatus 1 shown in FIG. 15, the container 10 is disposed in the vacuum chamber 40, the generating unit body 321 of the vibration generating unit 32 (vibration generating device) is disposed outside the vacuum chamber 40 (for example, in the atmosphere) below the container 10, and the shaft 322 of the vibration generating unit 32 connects the generating unit body 321 and the container 10. As described above, the chamber body 41 of the vacuum chamber 40 is a container having a bottom, and the bottom includes a partition member 81 as shown in FIG. 15. This partition member 81 is interposed between the generating unit body 321 of the vibration generating unit 32 and the container 10, and has, for example, a plate shape. A through hole having an inner diameter slightly larger than the outer diameter of the shaft 322 is formed in the partition member 81, and the shaft 322 is inserted into the through hole.

[0150] The powder film forming apparatus 1 shown in Fig. 15 includes an O-ring 80 as a sealing mechanism for maintaining the degree of vacuum in the vacuum chamber 40. The O-ring 80 is a member having a circular ring shape made of a material having rubber elasticity, for example. The O-ring 80 has a circular ring shape surrounding the shaft 322, and is disposed between the shaft 322 and a partition member 81. This allows the degree of vacuum in the vacuum chamber 40 to be maintained.

[0151] Fig. 16 is a side view of the powder film formation apparatus 1 according to the fifth modified example of the first embodiment, partially drawn in cross section. Fig. 16 differs from Fig. 13 in that a sealing mechanism is specifically illustrated. In the following, the configuration related to the sealing mechanism among the configuration of the powder film formation apparatus 1 shown in Fig. 16 will be mainly described, and the other configurations of the powder film formation apparatus 1 shown in Fig. 16 will be assigned the same reference numerals as in Fig. 13 and descriptions thereof will be omitted.

[0152] 16, similarly to the powder film formation apparatus 1 shown in FIG 15, the container 10 is disposed in the vacuum chamber 40, the generating unit body 321 of the vibration generating unit 32 is disposed below the container 10 and outside the vacuum chamber 40 (for example, in the atmosphere), and the shaft 322 of the vibration generating unit 32 connects the generating unit body 321 and the container 10. The bottom of the chamber body 41 of the vacuum chamber 40 includes a partition member 81 as shown in FIG 16. A through hole having an inner diameter slightly larger than the outer diameter of the shaft 322 is formed in the partition member 81, and the shaft 322 is inserted into the through hole.

[0153] The powder deposition apparatus 1 shown in Fig. 16 includes an O-ring 80 similar to that shown in Fig. 15 as a sealing mechanism for maintaining the degree of vacuum in the vacuum chamber 40. The O-ring 80 has an annular shape surrounding the shaft 322, and is disposed between the shaft 322 and a partition member 81. This allows the degree of vacuum in the vacuum chamber 40 to be maintained.

[0154] The reason why the generating unit body 321 of the vibration generating unit 32 is arranged outside the vacuum chamber 40, not inside the vacuum chamber 40, will be described. The generating unit body 321 includes a vibrator that generates vibrations. Examples of the vibrator include a type that uses an electromagnet and a type that uses a piezoelectric element. The vibrator includes various parts such as electronic components. Such a generating unit body 321 serves as a gas generating source. Therefore, when the generating unit body 321 is arranged in the vacuum chamber 40, gas components other than the process gas (e.g., the inert gas) may be mixed into the film formed on the surface of the powder F, and the film quality such as the conductivity may be deteriorated. In addition, when the gas generated due to the generating unit body 321 contains a lot of moisture, the crystallinity of the film may be impaired and the film quality may be deteriorated. In addition, when the generating unit body 321 is arranged in the vacuum chamber 40, the deterioration of the electronic components may be accelerated. Furthermore, since powder F is present in the vacuum chamber 40, if the generating unit body 321 is placed in the vacuum chamber 40, the powder F may get mixed into the generating unit body 321, leading to a breakdown of the generating unit body 321. Therefore, it is preferable that the container 10 is placed in the vacuum chamber 40, and the generating unit body 321 of the vibration generating unit 32 is placed outside the vacuum chamber 40.

[0155] The sealing mechanism may be, for example, a bellows. The bellows is a cylindrical, bellows-like member. The bellows is disposed, for example, between the lower surface of the container 10 and the upper surface of the partition member 81 so as to surround the shaft 322. The peripheral portion of the upper end of the bellows is fixed to the lower surface of the container 10, and the peripheral portion of the lower end of the bellows is fixed to the upper surface of the partition member 81 so as to maintain the vacuum degree of the vacuum chamber 40. The sealing mechanism may also be, for example, an oil seal. The oil seal has an inner peripheral portion (lip portion) that contacts the shaft 322, and an outer peripheral portion (fitting portion) that contacts the partition member 81.

[0156] However, the sealing mechanism is preferably an O-ring 80 in terms of durability as described below. The vibration generating unit 32 vibrates the container 10 in an oblique direction including a component in the direction of the central axis A of the container 10 and a component in the circumferential direction around the central axis A in order to transport the powder F arranged on the bottom surface 13 of the container 10 upward along the spiral transport path 31A. That is, the container 10 is torsionally vibrated in association with the vibration of the generating unit body 321 of the vibration generating unit 32. When the container 10 is vibrated in such an oblique direction, a force in a direction along the oblique direction acts on the sealing mechanism, and a torsional load is applied. The O-ring 80 is more durable against the torsional load than a bellows and an oil seal, and therefore the effect of maintaining the vacuum degree of the vacuum chamber 40 can be secured for a longer period of time than a bellows and an oil seal.

[0157] The powder film forming apparatus 1 may include only a single O-ring 80 as a sealing mechanism as shown in each of FIG. 15 and FIG. 16, or may include a plurality of (for example, two) O-rings 80 arranged at intervals in the axial direction of the shaft 322 as a sealing mechanism. The O-ring 80 may be arranged so that a part of the O-ring 80 fits into an annular groove (not shown) formed along the circumferential direction on the outer circumferential surface of the shaft 322. The O-ring 80 may be arranged so that a part of the O-ring 80 fits into an annular groove (not shown) formed along the circumferential direction on the inner circumferential surface of the partition member 81 surrounding the shaft 322. In the above specific example, the partition member 81 is a member constituting a part of the vacuum chamber 40, but may be a member constituting a part of the support table 90.

[0158] 1, 9, 11 and 13, specific illustrations of the sealing mechanism are omitted, but each of the powder film formation apparatuses 1 shown in Figures 1, 9, 11 and 13 includes a sealing mechanism for maintaining the degree of vacuum in the vacuum chamber 40, similar to the powder film formation apparatus 1 shown in Figure 15 or 16. Also, as shown in Figures 1, 9, 11 and 13, in each of the powder film formation apparatuses 1, the container 10 is disposed in the vacuum chamber 40, and the generating unit body 321 of the vibration generating unit 32 is disposed outside the vacuum chamber 40 (for example, in the atmosphere).

[0159] Next, the shape of the container 10 will be further described. Each container 10 of the powder film forming apparatus 1 shown in Figs. 1 to 12 and 15 is a cylindrical container having a bottom. On the other hand, each container 10 of the powder film forming apparatus 1 shown in Figs. 13, 14 and 16 is a stepped container in which the bottom surface 13, the inner surface 14 and the spiral transport path 31A are arranged in a step-like manner in the cross section shown in Figs. 13 and 16. When the total length of the spiral transport path 31A in the cylindrical container 10 and the total length of the spiral transport path 31A in the stepped container 10 are approximately the same, the cylindrical container 10 can have a smaller outer diameter than the stepped container 10, and as a result, the vacuum chamber 40 can be made compact.

[0160] The cylindrical container has an inner side surface 14 as shown in, for example, FIG. 1, FIG. 2, FIG. 5, and FIG. 15, and the stepped container 10 has an inner side surface 14 as shown in, for example, FIG. 10, FIG. 13, FIG. 14, and FIG. 16. The inner side surface 14 is a surface that rises vertically upward from the outer periphery of the bottom surface 13. In the case of the stepped container 10, the inner side surface 14 is not hidden behind the spiral conveying path 31A in plan view, as can be seen from, for example, the plan view shown in FIG. 14. Therefore, since the film forming material E that has become film-formable in the film forming source can easily reach many areas of the inner side surface 14 of the container 10, a film is formed on many areas of the inner side surface 14. On the other hand, in the case of the cylindrical container 10, many areas of the inner side surface 14 are hidden behind the spiral conveying path 31A in plan view, as can be seen from, for example, the perspective view in FIG. 2 and the plan view in FIG. 4. Therefore, the film-forming material E that has become film-formable in the film-forming source is unlikely to reach many areas of the inner surface 14. Therefore, in the cylindrical container 10, the ratio of the area on which a film is formed to the entire area of ​​the inner surface 14 is significantly smaller than that of the stepped container 10. Since the inner surface 14 of the container 10 is an area that does not need to be film-formed, forming a film on the inner surface 14 is wasteful and undesirable. Therefore, from this point of view, the cylindrical container 10 is preferable to the stepped container 10. In this way, in the cylindrical container 10, film formation in areas that do not need to be film-formed can be suppressed compared to the stepped container 10, and film formation can be efficiently performed on the powder F on the spiral conveying path 31A, the powder F on the inner guide path 31B, and the powder F on the bottom surface 13.

[0161] Next, the opening and closing structure of the vacuum chamber 40 will be further described. When the target (target 52 in each of FIGS. 1 and 15, and target 54 of the rotary cathode 53 in each of FIGS. 11, 13, and 16) is placed above the container 10 as shown in FIGS. 1, 11, 13, 15, and 16, the vacuum chamber 40 can be configured so that the lid 42 is attached to the upper part of the chamber body 41 via the hinge 43 so as to be openable and closable as shown in FIG. 3. On the other hand, when the rotary cathode 53 is placed vertically and the target 54 of the rotary cathode 53 is placed inside the container 10 as shown in FIG. 9, the vacuum chamber 40 is configured so that the top plate is removable from the chamber body, which is the part below the top plate. The rotary cathode 53 is fixed to the top plate. The rotary cathode 53 is placed at a predetermined position by attaching the top plate to the chamber body. Also, in FIG. 9, the top plate does not have to be integral with the chamber body and cannot be removed. In this case, a through hole through which the upper part of the rotary cathode 53 is inserted is formed in the top plate, and an adapter flange is attached to the upper part of the rotary cathode 53 located above the top plate. This adapter flange includes, for example, a power source and its wiring. The adapter flange and the rotary cathode 53 supported by it can be removed from the top plate by being lifted upward. The area between the adapter flange and the top plate is preferably sealed by a seal member (for example, an O-ring).

[0162] Next, the inner guide path 31B will be further described. The inner guide path 31B shown in each of Figs. 2, 4, 8, 12, and 14 has a curved shape (for example, a circular arc shape) in a plan view as described above, and is smoothly connected to the spiral conveying path 31A. Therefore, when the container 10 is torsionally vibrated with the vibration of the generating unit body 321 of the vibration generating unit 32, the powder F that reaches the upper end of the spiral conveying path 31A is smoothly carried into the inner guide path 31B, and the carried powder F is smoothly guided to the tip of the inner guide path 31B. If a linear guide path (linear chute) is connected to the upper part of the spiral conveying path 31A and the guide path is arranged so that the extension direction of the guide path is perpendicular to the tangential direction of the spiral conveying path 31A at the upper part of the spiral conveying path 31A in a plan view, the following problem occurs. In this case, the powder F that has reached the top of the spiral conveying path 31A is conveyed from the spiral conveying path 31A into the guide path perpendicular to the spiral conveying path 31A, but the direction of movement of the powder F immediately after being conveyed is along the tangential direction of the spiral conveying path 31A, not the direction of the guide path perpendicular to the spiral conveying path. Therefore, the powder F conveyed into the linear guide path will stagnate near the connection between the spiral conveying path 31A and the guide path, and part of the powder F on the guide path will overflow from the guide path and fall downward without reaching the tip of the guide path. As a result, it becomes difficult to uniformly mix the powder F in the container 10.

[0163] Specifically, when the container 10 is torsionally vibrated as described above, the powder F on the spiral conveying path 31A is given kinetic energy in a direction along the circumferential direction of the spiral conveying path 31A (for example, a tangential direction of the spiral conveying path 31A). Since the inner guide path 31B has a curved shape that is smoothly continuous with the spiral conveying path 31A, the powder F carried into the inner guide path 31B can move on the inner guide path 31B toward the tip of the inner guide path 31B by the kinetic energy given from the container 10. As described above with reference to FIG. 2, the inner guide path 31B has an upper surface on which the powder F is placed and a pair of side surfaces that rise upward from a pair of edges located on both sides of the upper surface, but the inner side surface of the pair of side surfaces can be omitted.

[0164] In addition, the tip of the inner guide path 31B is located above and away from the bottom surface 13 of the container 10. Therefore, the powder F guided to the tip of the inner guide path 31B falls freely toward the bottom surface 13 of the container 10, so that the powder F is prevented from agglomerating in the container 10. The powder F in the vacuum of the vacuum chamber 40 tends to agglomerate more easily than when in the atmosphere, but the powder F is prevented from agglomerating by falling freely from the tip of the inner guide path 31B to the bottom surface 13 of the container 10 as described above. This allows the powder F to be agitated more uniformly, and the film formed by the powder F becomes more uniform.

[0165] The powder F is also formed into a film while moving on the inner guide path 31B. Since the inner guide path 31B is relatively close to the film-forming source, the powder F on the inner guide path 31B is efficiently formed into a film. If the inner guide path is formed so as to continue from the upper end of the spiral conveying path 31A to the bottom surface 13 of the container 10, the degree of inclination of the inner guide path with respect to the horizontal plane becomes large. The speed of the powder F moving to the bottom surface 13 of the container 10 while being guided by such an inner guide path is inevitably likely to increase. In this case, the powder F is sparsely present on the inner guide path, and the proportion of the exposed portion of the upper surface of the inner guide path that is not covered by the powder F is likely to increase. In this way, the film-forming material E that has become film-formable in the film-forming source reaches the exposed portion of the upper surface of the inner guide path and forms a film. Since the upper surface of the inner guide path is an area that does not need to be film-formed, it is wasteful and undesirable to form a film on the upper surface of the inner guide path. Also, the powder F moving toward the bottom surface at a high speed along the inner guide path is less likely to be efficiently filmed. Therefore, in the powder film forming apparatus 1 according to the present embodiment, the degree of inclination of the inner guide path 31B with respect to the horizontal plane is set to be small so that the increase in the moving speed of the powder F guided by the inner guide path 31B can be suppressed to be relatively small. This suppresses the powder F from being sparsely present on the inner guide path 31B, and the powder F moving on the inner guide path 31B at a relatively slow speed is efficiently filmed. In addition, by reducing the degree of inclination of the inner guide path 31B with respect to the horizontal plane, the vertical distance between the tip of the inner guide path 31B and the bottom surface 13 of the container 10 can be increased. This makes it easier to increase the falling speed of the powder F that has fallen freely from the tip of the inner guide path 31B before it reaches the bottom surface 13 of the container 10. This makes it possible to further enhance the stirring effect of the powder F due to the free fall of the powder F.

[0166] It is preferable that the tip of the inner guide path 31B is located, for example, above the center in the up-down direction of the inner side surface 14 of the container 10. In addition, it is preferable that the vertical distance between the tip of the inner guide path 31B and the bottom surface 13 of the container 10 is greater than half the distance between the upper end of the container 10 and the bottom surface 13 of the container 10.

[0167] [Other variations] Although the powder film forming apparatus 1 according to the embodiment of the present disclosure has been described above, the present disclosure is not limited to these embodiments and may be modified as follows, for example.

[0168] (1) The powder moving mechanism of the device body does not have to have the vibration generating unit 32. For example, the powder moving mechanism may be equipped with a mechanism for transporting the powder from the bottom surface upward by a driving source such as a motor. An example of such a mechanism is a belt conveyor. The inner guide path of the upper transport path can be omitted. In the above embodiment, the powder transported upward by the upper transport path falls freely, but the present invention is not limited to this form. For example, the powder transported upward by the upper transport path may fall toward the bottom surface 13 along a guide path (not shown) that extends from the position toward the bottom surface 13 and guides the fall of the powder.

[0169] (2) The container is not limited to a cylindrical shape and may be another shape, for example, a rectangular parallelepiped shape, etc. Furthermore, the bottom surface of the container does not have to include an inclined surface.

[0170] (3) When a film formation process is performed by a method such as CVD that is performed in an atmosphere other than a vacuum atmosphere, the vacuum chamber can be omitted.

[0171] (4) The method of film formation is not limited to sputtering, arc ion plating, and plasma CVD.

[0172] (5) In the third embodiment, the inert gas supply unit 70 can be omitted.

[0173] (6) In each embodiment, the powder falling space S does not necessarily have to be provided in the center of the container 10, and may be provided in a position horizontally shifted from the center of the container 10.

[0174] (7) The spiral conveying path 31A as shown in Figures 13 and 14, i.e., a spiral conveying path having a shape that gradually moves away from the center of the container in a planar view as it moves upward, can be adopted in an apparatus that applies a film forming process to the surface of powder by arc ion plating, such as the powder coating apparatus of the second embodiment, and can also be adopted in an apparatus that applies a film forming process to the surface of powder by plasma CVD, such as the powder coating apparatus of the third embodiment.

[0175] (8) In each of the first to third modified examples of the first embodiment, the sputtering unit 50 includes a plurality of rotary cathodes 53, but is not limited to this. The sputtering unit 50 may include at least one rotary cathode 53. When the sputtering unit 50 includes only one rotary cathode 53, the rotary cathode 53 is connected to a DC power supply. [Explanation of symbols]

[0176] 1 Powder film deposition equipment 10 containers 13 Bottom of container 14 Inner surface of container 30 Powder Transfer Mechanism 31 Upper conveying path 31A Spiral conveyor 31B Inner guideway 32 Vibration generating unit 40 Vacuum Chamber 41 Chamber body 42 Lid 50 Sputtering Unit 50A Arc Ion Plating Unit 52 Target 53 Rotary Cathode 54 Target 60 Plasma Source 62 Raw gas supply pipe 63 Opening 70 Inert gas supply section A Central axis of the container E. Film-forming material that is ready for film formation F. Powder S Powder fall space

Claims

1. A powder film forming apparatus for performing a film forming process on a surface of a powder, comprising: an apparatus main body including a container having a bottom surface on which powder can be placed, the container having a powder drop space formed therein, the powder drop space being a space continuing upward from the bottom surface, the apparatus main body being configured such that an upper transport path is formed for transporting powder placed on the bottom surface of the container upward within an area of ​​the container other than the powder drop space, and the powder transported upward along the upper transport path can be dropped onto the bottom surface through the powder drop space; a film-forming source for making the film-forming material into a film-forming state capable of forming a film on the surface of the powder; the film formation source is configured to bring the film formation material into the film-formable state at least one of a position above the container and facing the bottom surface in the vertical direction and inside the container, and to supply the film formation material in the film-formable state to the bottom surface through the powder falling space; the upper conveying path includes a spiral conveying path extending upward from the bottom surface in a spiral shape, and an inner guide path extending from the upper end so as to guide the powder conveyed to the upper end of the spiral conveying path to a region radially inward of the container relative to the upper end, The inner guideway has a curved shape in a plan view, a tip end of the inner guide path is located above the center of the bottom surface of the container across the powder falling space, The powder deposition apparatus, wherein the apparatus main body further includes a vibration generating unit, and the vibration generating unit operates to vibrate the container in the vertical direction about its central axis and in the circumferential direction around the central axis, thereby transporting the powder placed on the bottom surface upward along the spiral transport path, guiding it along the curved inner guide path, and causing it to fall from the tip of the inner guide path.

2. A powder coating apparatus for performing a coating process on a surface of a powder, comprising: an apparatus main body including a container having a bottom surface on which powder can be placed, the container having a powder drop space formed therein, the powder drop space being a space continuing upward from the bottom surface, the apparatus main body being configured such that an upper transport path is formed for transporting powder placed on the bottom surface of the container upward within an area of ​​the container other than the powder drop space, and the powder transported upward along the upper transport path can be dropped onto the bottom surface through the powder drop space; a film-forming source for making the film-forming material into a film-forming state capable of forming a film on the surface of the powder; the film formation source is configured to bring the film formation material into the film-formable state at least one of a position above the container and facing the bottom surface in the vertical direction and inside the container, and to supply the film formation material in the film-formable state to the bottom surface through the powder falling space; the upper conveying path includes a spiral conveying path extending spirally upward from the bottom surface, a first guide wall provided at an upper portion of the spiral conveying path, and a second guide wall provided at a portion of the spiral conveying path upstream of the first guide wall in the conveying direction, A powder deposition apparatus, wherein each of the first guide wall and the second guide wall is configured to guide powder transported upward along the spiral transport path radially inward of the container further than the spiral transport path so as to cause the powder to fall from the spiral transport path toward the bottom surface.

3. The powder film forming apparatus according to claim 1 , wherein the film forming source is configured to supply the film forming material in the film-forming state also to at least a portion of the upper transport path.

4. A powder coating apparatus described in any one of claims 1 to 3, wherein the powder falling space is a space radially inward of the container than the spiral conveying path.

5. The powder deposition apparatus according to claim 1 , wherein the inner guide path includes a portion that slopes downward toward a tip of the inner guide path.

6. The bottom surface of the container includes an inclined surface that slopes downward from a center portion of the bottom surface toward an outer side in a radial direction of the container, The powder deposition apparatus according to claim 1 or 5, wherein the inner guide path is disposed so that a drop point of at least a part of the powder dropping from a tip of the inner guide path is the central part of the bottom surface.

7. The powder deposition apparatus according to claim 1 , wherein the spiral transport path has a shape that, in a plan view, gradually moves away from a center of the container as it goes upward.

8. The powder film forming apparatus is an apparatus for performing a film forming process on a surface of a powder by sputtering, the deposition source includes a cathode for the sputtering; 8. The powder deposition apparatus according to claim 1, wherein the cathode is disposed at a position vertically opposed to the bottom surface across the powder falling space.

9. The powder film forming apparatus is an apparatus for performing a film forming process on a surface of a powder by sputtering, 8. The powder deposition apparatus according to claim 1, wherein the deposition source includes at least one rotary cathode for the sputtering.

10. The powder film forming apparatus is an apparatus for performing a film forming process on a surface of a powder by sputtering, the deposition source includes at least one rotary cathode for the sputtering; the at least one rotary cathode includes a cylindrical target; The powder deposition apparatus according to any one of claims 1 to 7, wherein the target is arranged in such a manner that a central axis of the target faces in an up-down direction and at least a portion of the target faces the spiral transport path in a horizontal direction.

11. The powder film forming apparatus is an apparatus for performing a film forming process on a surface of a powder by arc ion plating, the deposition source includes a cathode for the arc ion plating; 8. The powder deposition apparatus according to claim 1, wherein the cathode is disposed at a position vertically opposed to the bottom surface across the powder falling space.

12. 12. The powder deposition apparatus according to claim 8, wherein an area of ​​the bottom surface overlapping with the powder falling space in a plan view has a size such that the cathode is included within the area in a plan view.

13. The powder film forming apparatus is an apparatus for performing a film forming process on a surface of a powder by plasma CVD, the film formation source includes a plasma source for bringing a raw material gas into the film formation state, 8. The powder deposition apparatus according to claim 1, wherein the plasma source is disposed at a position vertically opposed to the bottom surface across the powder falling space.

14. The powder deposition apparatus according to claim 13 , further comprising a source gas supply unit that supplies the source gas to a region affected by the plasma source.

15. 15. The powder deposition apparatus according to claim 14, wherein the plasma source has an opening formed in a lower portion of the plasma source and provided for discharging the plasma generated inside the plasma source to the outside of the plasma source.

16. 16. The powder deposition apparatus according to claim 15, wherein the raw material gas supply unit has a pipe arranged in a ring shape so as to surround the opening of the plasma source in a plan view, and is configured so as to be able to supply the raw material gas below the plasma source from a gas supply hole formed in the pipe.

17. 17. The powder deposition apparatus according to claim 15, wherein an area of ​​the bottom surface overlapping with the powder falling space in a plan view has a size such that the opening of the plasma source is included within the area in a plan view.

18. The powder deposition apparatus according to any one of claims 13 to 17, further comprising an inert gas supply unit that supplies an inert gas into the container so that the raw material gas in the film-forming state is guided toward the bottom surface in the powder falling space.

19. a vacuum chamber for housing the container; The container has an upwardly opening shape, The powder film forming apparatus according to any one of claims 1 to 18, wherein the film forming material is brought into the film-forming state at least one of above the container and inside the container in the vacuum chamber.

20. The vacuum chamber comprises: a chamber body that defines an internal space for accommodating the container and is open upward; The powder deposition apparatus according to claim 19 , further comprising: a lid portion attached to an upper portion of the chamber body in an openable and closable manner.

21. a vacuum chamber for housing the container; The vibration generating unit includes a generating unit body that generates vibrations, and a shaft that connects the generating unit body and the container, The powder deposition apparatus according to claim 1 , wherein the generation unit body is disposed outside the vacuum chamber.

22. A powder film-forming method for performing a film-forming process on a surface of a powder by using the powder film-forming apparatus according to any one of claims 1 to 21, placing a powder in the container; conveying the powder in the container along the upward conveying path, and allowing the powder conveyed upward to fall onto the bottom surface through the powder falling space; and forming a film on a surface of powder using the film-forming material that has become capable of forming a film.

Images