Particle coating apparatus and particle coating method

Abstract

The present invention provides a particle coating apparatus and a particle coating method capable of improving yield. [Solution] A particle coating apparatus 1 for forming an insulating film on the surface of metal particles 31 by atomic layer deposition, comprising: a chamber 11 in which the metal particles 31 are arranged and which has an opening and closing part; a raw material gas supply unit 16 for supplying raw material gas 41 into the chamber 11; a reaction gas supply unit 17 for supplying reaction gas 42 into the chamber 11; a dust collection and recovery chamber 100 connected to the chamber 11 for collecting and recovering the metal particles 31 discharged from the chamber 11 together with the raw material gas 41 and the metal particles 31 discharged from the chamber 11 together with the reaction gas 42; and a suction pump 18 for discharging the raw material gas 41 or reaction gas 42 from inside the chamber 11 through the dust collection and recovery chamber 100.

Description

Technical Field

[0001] The present invention relates to a particle coating device and a particle coating method.

Background Art

[0002] Patent Document 1 discloses a configuration of a particle coating device in which particles are housed in a bottomed cylindrical particle container, and a coating material is sputtered onto the particles while the particle container is tilted and rotated. As a method for forming a coating film on particles, ALD (Atomic Layer Deposition), which can form a film at the atomic layer level, is known. ALD forms a film by supplying and exhausting a raw material gas in a chamber and then supplying and exhausting a reaction gas.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional method, when exhausting the gas, the rolled-up particles flow out of the chamber together with the gas, and the outflowed particles cannot be recovered, that is, there is a problem that the yield decreases.

Means for Solving the Problems

[0005] The particle coating apparatus is a particle coating apparatus that forms a coating on the surface of a powder to be processed by atomic layer deposition, and comprises: a processing chamber in which the powder to be processed is placed and which has an opening and closing section; a raw material gas supply section for supplying raw material gas into the processing chamber; a reaction gas supply section for supplying reaction gas into the processing chamber; a dust collection and recovery chamber connected to the processing chamber for collecting and recovering the powder to be processed that is discharged from the processing chamber together with the raw material gas and the powder to be processed that is discharged from the processing chamber together with the reaction gas; and a suction pump for discharging the raw material gas or the reaction gas from the processing chamber through the dust collection and recovery chamber.

[0006] The particle coating method is a particle coating method that forms a coating on the surface of a powder to be treated by atomic layer deposition, and comprises the steps of: placing the powder to be treated into the processing chamber through an opening / closing section of the processing chamber; supplying a raw material gas into the processing chamber; a first exhaust step of operating a suction pump via a dust collection and recovery chamber communicating with the processing chamber after or simultaneously with the supply of the raw material gas to exhaust the raw material gas and the powder to be treated contained in the raw material gas from the processing chamber to the dust collection and recovery chamber; supplying a reaction gas into the processing chamber; and a second exhaust step of operating a suction pump via the dust collection and recovery chamber after or simultaneously with the supply of the reaction gas to exhaust the reaction gas and the powder to be treated contained in the reaction gas from the processing chamber to the dust collection and recovery chamber, wherein the first exhaust step and the second exhaust step recover the powder to be treated contained in the raw material gas and the powder to be treated contained in the reaction gas using a dust collection and recovery mechanism provided in the dust collection and recovery chamber. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram showing the configuration of a particle coating device. [Figure 2] A cross-sectional view showing the structure of particles with an insulating film. [Figure 3] A flowchart illustrating the particle coating method. [Figure 4] A diagram illustrating the particle coating method of this embodiment. [Figure 5] A diagram illustrating the particle coating method of this embodiment. [Figure 6] A diagram illustrating the particle coating method of this embodiment. [Figure 7] A diagram illustrating the particle coating method of this embodiment. [Figure 8] A diagram illustrating the particle coating method of this embodiment. [Figure 9] A diagram illustrating the particle coating method of this embodiment. [Figure 10] A diagram illustrating the particle coating method of this embodiment. [Figure 11] A diagram showing a modified particle coating method. [Figure 12] A diagram showing a modified particle coating method. [Modes for carrying out the invention]

[0008] The particle coating apparatus 1 and the particle coating method will be described below with reference to the drawings. First, the configuration of the particle coating apparatus 1 will be described with reference to Figure 1.

[0009] As shown in Figure 1, the particle coating apparatus 1 is a device that forms an insulating film 32 as a coating on the surface of metal particles 31, which are powders to be treated, by, for example, atomic layer deposition (ALD), thereby forming insulating film-coated particles 33 (see Figure 2).

[0010] The particle coating apparatus 1 comprises a chamber 11 as a processing chamber, a dust collection and recovery chamber 100, a raw material gas supply unit 16, a reaction gas supply unit 17, and a suction pump 18. The chamber 11 has a tray 12, a mounting unit 14, and a heating unit 15.

[0011] The chamber 11 is rigid and airtight, and has a volume of, for example, 10 L to 100 L. The chamber 11 has an opening / closing section (not shown), through which the tray 12 holding the powder layer 30 of metal particles 31 is loaded into and unloaded from the opening / closing section. With the metal particles 31 contained inside the chamber 11, an insulating film 32 is formed on the surface of the metal particles 31.

[0012] Chamber 11 is maintained in a reduced pressure state by evacuating its interior. Examples of the constituent material of Chamber 11 include glass materials such as quartz glass, ceramic materials such as alumina, and metal materials such as stainless steel, aluminum, and titanium.

[0013] Chamber 11 is connected to a raw material gas supply unit 16 and a reaction gas supply unit 17. The raw material gas supply unit 16 supplies a raw material gas 41 into Chamber 11. A pipe 21a is connected between the raw material gas supply unit 16 and Chamber 11. A valve 21 is provided in the pipe 21a. By opening and closing the valve 21, the raw material gas 41 necessary for forming the insulating film 32 can be supplied into Chamber 11, and the partial pressure of the raw material gas 41 in Chamber 11 can be adjusted.

[0014] Examples of the raw material gas 41 include, for example, a gas containing a precursor of the insulating film 32. Specifically, for example, when forming a silicon-based insulating film 32, as the raw material gas 41, secondary amines such as dimethylamine, methylethylamine, and diethylamine, and reactants of secondary amines and trihalosilane such as tris(dimethylamino)silane, bis(diethylamino)silane, and bis(tert-butylamino)silane can be mentioned.

[0015] The reaction gas supply unit 17 supplies a reaction gas 42 into Chamber 11. A pipe 22a is connected between the reaction gas supply unit 17 and Chamber 11. A valve 22 is provided in the pipe 22a. By opening and closing the valve 22, the reaction gas 42 necessary for forming the insulating film 32 can be supplied into Chamber 11, and the partial pressure of the reaction gas 42 in Chamber 11 can be adjusted.

[0016] The reaction gas 42 is an oxidizing agent such as, for example, oxygen gas. Examples of the oxidizing agent include, for example, ozone, plasma oxygen, water vapor, and the like. By using ozone as the oxidizing agent, a more dense and uniform-thickness insulating film 32 can be formed more efficiently. The source gas 41 and the reaction gas 42 are supplied together with a carrier gas mainly composed of an inert gas such as nitrogen gas or argon gas as necessary.

[0017] The chamber 11 has a plasma generation unit (not shown) that generates oxygen plasma using oxygen gas. Thus, since the plasma generation unit is disposed inside the chamber 11, an insulating film 32 can be formed on the surface of the metal particles 31 by utilizing the chemical reaction between the source gas 41 and the reaction gas 42.

[0018] The trays 12 are stacked and arranged inside the chamber 11. The trays 12 hold the metal particles 31 in the state of a powder layer 30 formed by laying the metal particles 31 in layers. Holding means maintaining the relative positions of the metal particles 31 so as not to change, and specifically means that the powder layer 30 is static. By arranging a plurality of trays 12 in a stacked manner, the plurality of trays 12 can be arranged in a space-saving manner. Also, in the formation of the insulating film 32 once, many metal particles 31 can be processed. Thereby, while achieving space saving of the particle coating device 1, the production efficiency of the particles 33 with an insulating film coated with the insulating film 32 can be increased.

[0019] Inside the chamber 11, a leg portion 13 and a mounting portion 14 are provided. The leg portion 13 extends upward from the bottom surface inside the chamber 11. A plurality of leg portions 13 are arranged on the bottom surface at a predetermined interval. A plurality of mounting portions 14 arranged at a predetermined interval are attached to the leg portion 13. The mounting portion 14 is configured to support the tray 12 from below. Therefore, the plurality of trays 12 are supported in a detachable state by the plurality of mounting portions 14.

[0020] The heating unit 15 heats the chamber 11, and consequently heats the powder layer 30. The heating unit 15 is positioned to surround the outside of the chamber 11. Examples of the heating unit 15 include a heater block, film heater, sheet heater, sheath heater, infrared radiation heater, etc. The heating unit 15 is not limited to being positioned outside the chamber 11, but may also be positioned inside the chamber 11.

[0021] The presence of the heating unit 15 allows for the optimization of the temperature of the powder layer 30, the raw material gas 41, and the reaction gas 42. This enables the more efficient formation of a denser, more uniformly filmed insulating film 32.

[0022] The dust collection chamber 100 is connected to the inside of the chamber 11 via a connection part 200 so as to be able to communicate with it. The dust collection chamber 100 collects metal particles 31 discharged from the chamber 11 together with the raw material gas 41 and metal particles 31 discharged from the chamber 11 together with the reaction gas 42.

[0023] A cyclone mechanism is located in the dust collection chamber 100. The cyclone mechanism collects the metal particles 31 at the bottom of the dust collection chamber 100 by centrifugal force and gravity. Inside the dust collection chamber 100, there is a conical inclined section 110 with an opening 111 in the center, which causes the metal particles 31 to fall towards the center while rotating.

[0024] The dust collection chamber 100 is provided with a recovery opening / closing section 120 that allows the metal particles 31 collected in the dust collection chamber 100 to be removed from the dust collection chamber. Because the recovery opening / closing section 120 is provided, it is possible to remove the metal particles 31 and insulating film-coated particles 33 collected in the dust collection chamber 100, thereby improving the production yield of the metal particles 31 and insulating film-coated particles 33.

[0025] Furthermore, a heating unit 130 for heating the collected metal particles 31 is located at the bottom of the dust collection chamber 100. Because the heating unit 130 is located in the dust collection chamber 100, it becomes possible to form an insulating film 32 on the surface of the metal particles 31 collected in the dust collection chamber 100 using the raw material gas 41 and the reaction gas 42, thereby forming insulating film-coated particles 33.

[0026] Furthermore, an exhaust port 140 is provided at the top of the dust collection chamber 100 for exhausting exhaust gas, specifically the raw material gas 41 and reaction gas 42. Since the exhaust port 140 is provided at the top of the dust collection chamber 100, the metal particles 31 flowing from the chamber 11 can be collected at the bottom of the dust collection chamber 100 using a cyclone system, and only the exhaust gas can be exhausted from the dust collection chamber 100.

[0027] The suction pump 18 discharges the raw material gas 41 and reaction gas 42 supplied to the chamber 11 and the dust collection chamber 100. A pipe 23a is connected between the suction pump 18 and the dust collection chamber 100. A valve 23 is provided in the pipe 23a. By opening and closing the valve 23, the pressure inside the chamber 11 and the dust collection chamber 100 can be reduced.

[0028] Specifically, the raw material gas 41 and reaction gas 42 can be supplied into the chamber 11 and the dust collection and recovery chamber 100, and the raw material gas 41 and reaction gas 42 can be exhausted from the chamber 11 and the dust collection and recovery chamber 100. The suction pump 18 is, for example, a vacuum pump. The pressure inside the chamber 11 is measured by a vacuum gauge 19.

[0029] As described above, since the dust collection and recovery chamber 100 is positioned between the chamber 11 and the suction pump 18, metal particles 31 that are stirred up when the raw material gas 41 and reaction gas 42 in the chamber 11 are exhausted can be recovered in the dust collection and recovery chamber 100. Therefore, it is possible to prevent metal particles 31 from entering the suction pump 18, and the loss of metal particles 31 can be reduced. As a result, the manufacturing yield of insulating film-coated particles 33 can be improved.

[0030] Next, the structure of the insulating film-coated particle 33 will be described with reference to Figure 2.

[0031] As shown in Figure 2, the insulating film-coated particle 33 has a metal particle 31 and an insulating film 32.

[0032] Examples of materials that can be used to make up the metal particles 31 include soft magnetic metal materials. When metal particles 31 made of soft magnetic metal materials are used in magnetic elements such as inductors, it is necessary to ensure insulation between the metal particles 31.

[0033] By using the particle coating apparatus 1 described above, an insulating film 32 with a sufficiently thin film thickness and high coverage can be formed. This results in insulating film-coated particles 33 that can enhance the magnetic and insulating properties of magnetic elements. Furthermore, because the insulating film 32 formed by atomic layer deposition is dense, it also contributes to the realization of insulating film-coated particles 33 with high insulating properties.

[0034] Examples of soft magnetic metal materials include pure iron, Fe-Si alloys such as silicon steel, Fe-Ni alloys such as permalloy, Fe-Co alloys such as permendur, Fe-Si-Al alloys such as sendust, Fe-Cr-Si alloys and various other Fe-based alloys, as well as various Ni-based alloys, various Co-based alloys, and various amorphous alloys. Among these, examples of amorphous alloys include Fe-based alloys such as Fe-Si-B, Fe-Si-BC, Fe-Si-B-Cr-C, Fe-Si-Cr, Fe-B, Fe-PC, Fe-Co-Si-B, Fe-Si-B-Nb, and Fe-Zr-B, Ni-based alloys such as Ni-Si-B and Ni-PB, and Co-based alloys such as Co-Si-B.

[0035] The average particle size of the metal particles 31 is, for example, 2 μm or less. However, the average particle size of the metal particles 31 is not limited to 2 μm or less, and may be, for example, between 0.1 μm and 50.0 μm.

[0036] The insulating film 32 is composed of insulating materials, such as oxides like silicon dioxide, hafnium oxide, tantalum oxide, titanium oxide, and chromium oxide.

[0037] Next, a particle coating method for forming an insulating film 32 on the surface of metal particles 31 will be described with reference to Figures 3 to 10. The insulating film 32 is formed using atomic layer deposition.

[0038] As shown in Figure 3, in step S11 (the placing step), the metal particles 31 are placed in the chamber 11. Specifically, as shown in Figure 4, a tray 12 holding the powder layer 30 of the metal particles 31 is brought into the chamber 11 of the particle coating apparatus 1 through an opening / closing part (not shown). Then, the tray 12 is placed on the placement section 14.

[0039] Next, in step S12 (the process of supplying the raw material gas), the raw material gas 41 is supplied into the chamber 11. Specifically, first, as shown in Figure 5, the chamber 11 is evacuated using the suction pump 18 to reduce the pressure inside the chamber 11. Then, if necessary, the metal particles 31 introduced into the chamber 11 are subjected to pretreatment. Examples of pretreatment include ozone treatment, radical treatment, ultraviolet treatment, plasma treatment, corona treatment, drying treatment, and solvent treatment. Note that the pretreatment may be performed after the heating process described later.

[0040] Next, the heating unit 15 is used to heat the inside of the chamber 11, thereby heating the metal particles 31 placed inside the chamber 11. This heating may overlap in time with the deposition of the insulating film 32, which will be described later, or it may be performed separately from the deposition, i.e., without overlapping in time. The heating temperature is, for example, 30°C to 500°C. In this way, heating under reduced pressure suppresses the oxidation of the metal particles 31 and suppresses the increase in coercivity associated with oxidation.

[0041] Next, as shown in Figure 6, the raw material gas 41 is supplied into the chamber 11. Specifically, the valve 21 is opened to introduce the raw material gas 41 into the chamber 11 from the raw material gas supply unit 16. The introduced raw material gas 41 is adsorbed onto the surface of the metal particles 31. At this time, once the raw material gas 41 is adsorbed onto the surface of the metal particles 31, it is difficult for it to adsorb in any further layers. Therefore, it is possible to control the thickness of the insulating film 32 obtained in the end with high precision. In addition, since the raw material gas 41 also wraps around and adsorbs into the shadows and gaps of the metal particles 31, the thickness of the insulating film 32 is made uniform.

[0042] Next, in step S13 (first exhaust process), the raw material gas 41 is exhausted from inside the chamber 11 to the dust collection and recovery chamber 100, which is connected to it. Specifically, as shown in Figures 6 and 7, the valve 21 connected to the raw material gas supply unit 16 is closed, and the valve 23 connected to the suction pump 18 is opened. Next, the suction pump 18 is operated to exhaust the raw material gas 41 from inside the chamber 11 to the dust collection and recovery chamber 100.

[0043] At this time, the metal particles 31 that are stirred up move to the dust collection chamber 100 along with the exhausted raw material gas 41. The timing of exhausting the raw material gas 41 may be either after the process of supplying the raw material gas 41, or simultaneously with the process of supplying the raw material gas 41.

[0044] As described above, the metal particles 31 discharged together with the raw material gas 41 move into the dust collection chamber 100. The metal particles 31 rotate along the conical inclined section 110 having an opening 111 under centrifugal force and fall out of the opening 111. In other words, the metal particles 31 that have flowed out of the chamber 11 are collected using a cyclone system.

[0045] Furthermore, the dust collection chamber 100 is heated by the heating unit 130 (heating process). Therefore, the metal particles 31 collected in the dust collection chamber 100 are also heated. The exhausted raw material gas 41 is adsorbed onto the surface of the collected metal particles 31.

[0046] Next, in step S14 (the process of supplying reaction gas), reaction gas 42 is supplied into the chamber 11. First, an inert gas such as nitrogen gas or argon gas is introduced as needed. This replaces the raw material gas 41. The introduction of the inert gas can be carried out in the same manner as the introduction of the raw material gas 41 and reaction gas 42, although this is not shown in the diagram. After that, the inert gas is discharged using the suction pump 18.

[0047] Next, as shown in Figure 8, reaction gas 42 is introduced into the chamber 11 from the reaction gas supply unit 17. As mentioned above, the reaction gas 42 can be an oxidizing agent such as ozone, plasma oxygen, or water vapor. The reaction gas 42 reacts with the raw material gas 41 adsorbed on the surface of the metal particles 31 to form an insulating film 32.

[0048] Next, in step S15 (second exhaust process), the reaction gas 42 is exhausted from inside the chamber 11 to the dust collection and recovery chamber 100, which is connected to it. Specifically, as shown in Figures 8 and 9, the valve 22 connected to the reaction gas supply unit 17 is closed, and the valve 23 connected to the suction pump 18 is opened. Next, the suction pump 18 is operated to exhaust the reaction gas 42 from inside the chamber 11 to the dust collection and recovery chamber 100.

[0049] At this time, the metal particles 31 that are stirred up move to the dust collection chamber 100 along with the exhausted reaction gas 42. The metal particles 31 rotate along the conical inclined section 110 having an opening 111, under centrifugal force, and fall out of the opening 111. In other words, the metal particles 31 that have flowed out of the chamber 11 are collected using a cyclone system. The timing of exhausting the reaction gas 42 may be either after the step of supplying the reaction gas 42, or simultaneously with the step of supplying the reaction gas 42.

[0050] The dust collection chamber 100 is heated by the heating unit 130 (heating process). Therefore, the metal particles 31 collected in the dust collection chamber 100 are also heated. The exhausted reaction gas 42 reacts with the raw material gas 41 adsorbed on the surface of the metal particles 31, forming an insulating film 32 on the surface of the metal particles 31. Thus, the particles 33 with an insulating film are completed.

[0051] As described above, a dust collection chamber 100 is positioned between the chamber 11 and the suction pump 18. Since a cyclone system is used as the dust collection mechanism in the dust collection chamber 100, metal particles 31 that are stirred up when the raw material gas 41 and reaction gas 42 in the chamber 11 are exhausted to the dust collection chamber 100 can be recovered in the dust collection chamber 100. Therefore, it is possible to prevent metal particles 31 from entering the suction pump 18, and insulating film particles 33 can be recovered in both the chamber 11 and the dust collection chamber 100. This makes it possible to reduce the loss of insulating film particles 33 and improve the yield.

[0052] Furthermore, the introduction and discharge of the raw material gas 41 and the reaction gas 42 can be repeated according to the required thickness of the insulating film 32. The thickness of the insulating film 32 can be increased according to the number of repetitions. This makes it easy to obtain the desired thickness.

[0053] Subsequently, the insulating film-coated particles 33 may be subjected to post-treatment as needed. Examples of post-treatment include static elimination treatment and radical treatment. Of these, static elimination treatment is a treatment that reduces the amount of charge due to the charging of the insulating film-coated particles 33. For example, an ionizer can be used for static elimination treatment.

[0054] Examples of constituent materials for the formed insulating film 32 include oxides such as silicon oxide, hafnium oxide, tantalum oxide, titanium oxide, and chromium oxide, and nitrides such as aluminum nitride, titanium nitride, and tantalum nitride. The thickness of the insulating film 32 is not particularly limited, but as an example, it is between 1 nm and 500 nm.

[0055] Next, in step S16, the insulating film particles 33 are recovered. Specifically, as shown in Figure 10, the insulating film particles 33 formed in the chamber 11 can be removed together with the tray 12 from an opening / closing part (not shown). The insulating film particles 33 formed in the dust collection and recovery chamber 100 can be removed from the recovery opening / closing part 120. Therefore, it becomes possible to recover metal particles 31 and insulating film particles 33 that were not recovered in the conventional method, thereby improving the yield.

[0056] As described above, the particle coating apparatus 1 of this embodiment is a particle coating apparatus 1 that forms an insulating film 32 on the surface of metal particles 31 by atomic layer deposition, and comprises a chamber 11 in which metal particles 31 are arranged and which has an opening and closing part, a raw material gas supply unit 16 that supplies raw material gas 41 into the chamber, a reaction gas supply unit 17 that supplies reaction gas 42 into the chamber 11, a dust collection and recovery chamber 100 connected to the chamber 11 that collects and recovers the metal particles 31 discharged from the chamber 11 together with the raw material gas 41 and the metal particles 31 discharged from the chamber 11 together with the reaction gas 42, and a suction pump 18 that discharges the raw material gas 41 or reaction gas 42 from inside the chamber 11 through the dust collection and recovery chamber 100.

[0057] With this configuration, a dust collection and recovery chamber 100 is positioned between the chamber 11 and the suction pump 18, so that metal particles 31 and insulating film particles 33 that are stirred up when the gas from the chamber 11 is exhausted can be recovered in the dust collection and recovery chamber 100. Therefore, it is possible to prevent metal particles 31 and insulating film particles 33 from entering the suction pump 18, and metal particles 31 and insulating film particles 33 can be recovered in both the chamber 11 and the dust collection and recovery chamber 100. As a result, it is possible to reduce the loss of metal particles 31 and insulating film particles 33 and improve yield.

[0058] Furthermore, in the particle coating apparatus 1 of this embodiment, it is preferable that the dust collection and recovery chamber 100 has a recovery opening / closing section 120 that allows the metal particles 31 and insulating film particles 33 collected in the dust collection and recovery chamber 100 to be taken out of the dust collection and recovery chamber 100. With this configuration, since the dust collection and recovery chamber 100 is provided with a recovery opening / closing section 120, it becomes possible to take out the metal particles 31 and insulating film particles 33 collected in the dust collection and recovery chamber 100, and the yield of insulating film particles 33 can be improved.

[0059] Furthermore, in the particle coating apparatus 1 of this embodiment, it is preferable that a cyclone mechanism that collects dust using centrifugal force is arranged in the dust collection chamber 100. With this configuration, since the cyclone mechanism is arranged in the dust collection chamber 100, the metal particles 31 and insulating film-coated particles 33 that have flowed from the chamber 11 can be collected in the dust collection chamber 100 by centrifugal force and their own weight.

[0060] Furthermore, in the particle coating apparatus 1 of this embodiment, it is preferable that a heating unit 130 for heating the collected metal particles 31 is arranged in the dust collection and recovery chamber 100. With this configuration, since the heating unit 130 is arranged in the dust collection and recovery chamber 100, an insulating film 32 can be formed on the surface of the metal particles 31 collected in the dust collection and recovery chamber 100 using the raw material gas 41 and the reaction gas 42.

[0061] Furthermore, in the particle coating apparatus 1 of this embodiment, it is preferable that the chamber 11 has a plurality of trays 12 that hold a powder layer 30 in which metal particles 31 are laid in layers, and a mounting section 14 on which the plurality of trays 12 are placed in a removable manner. With this configuration, since the metal particles 31 are held in the plurality of trays 12 inside the chamber 11, an insulating film 32 can be formed on the plurality of metal particles 31 simultaneously.

[0062] Furthermore, in the particle coating apparatus 1 of this embodiment, it is preferable that the reaction gas 42 is oxygen gas, and the chamber 11 has a plasma generation unit that generates oxygen plasma using oxygen gas. With this configuration, since the plasma generation unit is located in the chamber 11, an insulating film 32 can be formed on the surface of the metal particles 31 by utilizing the chemical reaction between the raw material gas 41 and the reaction gas 42.

[0063] Furthermore, the particle coating method of this embodiment is a particle coating method in which an insulating film 32 is formed on the surface of metal particles 31 by atomic layer deposition, and comprises the steps of: placing the metal particles 31 in the chamber 11 through the opening and closing part of the chamber 11; supplying raw material gas 41 into the chamber 11; and after the step of supplying the raw material gas 41, or simultaneously with the step of supplying the raw material gas 41, operating a suction pump 18 via a dust collection and recovery chamber 100 communicating with the chamber 11 to exhaust the raw material gas 41 and the metal particles 31 contained in the raw material gas 41 from the chamber 11 to the dust collection and recovery chamber 100. The process includes a gas step, a step of supplying reaction gas 42 into the chamber 11, and a second exhaust step which, after or simultaneously with the step of supplying reaction gas 42, operates a suction pump 18 via the dust collection and recovery chamber 100 to exhaust the reaction gas 42 and the metal particles 31 contained in the reaction gas 42 from the chamber 11 to the dust collection and recovery chamber 100. The first and second exhaust steps use a dust collection and recovery mechanism, i.e., a cyclone mechanism, provided in the dust collection and recovery chamber 100 to recover the metal particles 31 contained in the raw material gas 41 and the metal particles 31 contained in the reaction gas 42.

[0064] This method utilizes a cyclone mechanism in the dust collection chamber 100, allowing metal particles 31 that are stirred up when the raw material gas 41 and reaction gas 42 from the chamber 11 are exhausted to the dust collection chamber 100 to be recovered in the dust collection chamber 100. Therefore, it is possible to prevent metal particles 31 and insulating film particles 33 from entering the suction pump 18, and metal particles 31 and insulating film particles 33 can be recovered in both the chamber 11 and the dust collection chamber 100. This reduces the loss of insulating film particles 33 and improves yield.

[0065] Furthermore, in the particle coating method of this embodiment, it is preferable that the first exhaust step and the second exhaust step include a step of heating the metal particles 31 collected in the dust collection chamber 100. According to this method, since the metal particles 31 in the dust collection chamber 100 are heated, an insulating film 32 can be formed on the surface of the metal particles 31 in the dust collection chamber 100, similar to the chamber 11.

[0066] Furthermore, in the particle coating method of this embodiment, the dust collection mechanism is preferably a cyclone type. With this method, since dust is collected using a cyclone system, the metal particles 31 and insulating film-coated particles 33 that have flowed from the chamber 11 can be collected in the dust collection chamber 100 by centrifugal force and their own weight.

[0067] Furthermore, in the particle coating method of this embodiment, it is preferable that the metal particles 31 are made of a soft magnetic metal material and the insulating film 32 is made of an insulating material. With this method, since the insulating film 32 of the insulating material is formed on the surface of the metal particles 31 of the soft magnetic metal material, it is possible to form particles with a desired configuration.

[0068] The following describes some variations of the embodiments described above.

[0069] As described above, the method for recovering metal particles 31 in the dust collection chamber 100 is not limited to applying a cyclone mechanism using a cyclone system, but may also be applied using a glow discharge system.

[0070] As shown in Figure 11, the modified particle coating device 1A has a glow discharge mechanism located inside the dust collection chamber 100A. Specifically, a charging section 300 is located on the side of the connection section 200 of the dust collection chamber 100A. Two electrodes 411 and 412, to which a (+) potential is applied, are located above and below the charging section 300. When current flows between the two electrodes 411 and 412, the metal particles 31 become (-) charged. On the other hand, a dust collection section 400 is located on the side of the suction pump 18 of the dust collection chamber 100A. Two electrodes 421 and 422, to which a (+) potential is applied, are located above and below the dust collection section 400. An electrode 423, to which a (-) potential is applied, is located between the two electrodes 421 and 422. A heating section 130 is located outside the two electrodes 421 and 422 in the dust collection section 400. The temperature of the heating unit 130 is the same as the temperature of the heating unit 15 located in the chamber 11.

[0071] As shown in Figure 12, when exhausting the chamber 11, specifically when creating a vacuum, exhausting the raw material gas 41, or exhausting the reaction gas 42, the metal particles 31 that have flowed from the chamber 11 through the connection part 200 become negatively charged by glow discharge in the charging part 300. Next, the negatively charged metal particles 31 are collected on the positive electrodes 421 and 422 in the dust collection part 400. In this way, by applying the glow discharge method in the dust collection chamber 100A, the metal particles 31 that have flowed from the chamber 11 can be collected in the dust collection chamber 100A by charging and dust collection. The collected metal particles 31 are heated by the heating part 130 and reacted with the raw material gas 41 and the reaction gas 42, similar to the cyclone method described above, and an insulating film 32 is formed on their surface.

[0072] As described above, in the modified particle coating apparatus 1A, it is preferable that a glow discharge mechanism for collecting dust using glow discharge is arranged in the dust collection chamber 100A. Furthermore, it is preferable that the dust collection mechanism is of the glow discharge type. With this configuration, since a glow discharge mechanism is arranged in the dust collection chamber 100 and the glow discharge type is used, metal particles 31 and insulating film-coated particles 33 that have flowed from the chamber 11 can be collected in the dust collection chamber 100A by charging and dust collection. [Explanation of symbols]

[0073] 1,1A...Particle coating device, 11...Chamber as processing chamber, 12...Tray, 13...Legs, 14...Placement section, 15...Heating section, 16...Raw material gas supply section, 17...Reaction gas supply section, 18...Suction pump, 19...Vacuum gauge, 21...Valve, 21a...Piping, 22...Valve, 22a...Piping, 23...Valve, 23a...Piping, 30...Powder layer, 31...Metal particles as powder to be processed, 32...Insulating film as coating, 33...Particles with insulating film, 41...Raw material gas, 42...Reaction gas, 100,100A...Dust collection and recovery chamber, 110...Inclined section, 111...Opening hole, 120...Recovery opening / closing section, 130...Heating section, 140...Exhaust port, 200...Connection section, 300...Charging section, 400...Dust collection section, 411,412,421,422,423...Electrodes.

Claims

1. A particle coating apparatus that forms a coating on the surface of a powder to be treated by atomic layer deposition, A processing chamber in which the powder to be processed is placed and which has an opening and closing section, A raw material gas supply unit that supplies raw material gas into the processing chamber, A reaction gas supply unit that supplies reaction gas into the processing chamber, A dust collection and recovery chamber connected to the processing chamber, which collects and recovers the powder to be processed that is discharged from the processing chamber together with the raw material gas, and the powder to be processed that is discharged from the processing chamber together with the reaction gas. A suction pump that discharges the raw material gas or the reaction gas from the processing chamber through the dust collection and recovery chamber, A particle coating device equipped with the following features.

2. A particle coating apparatus according to claim 1, The particle coating apparatus comprises a dust collection and recovery chamber having a recovery opening / closing section that allows the powder to be processed, which has been collected in the dust collection and recovery chamber, to be taken out of the dust collection and recovery chamber.

3. A particle coating apparatus according to claim 1, The particle coating device is equipped with a cyclone mechanism that collects dust using centrifugal force in the dust collection chamber.

4. A particle coating apparatus according to claim 1, The particle coating device is equipped with a glow discharge mechanism that collects dust using glow discharge in the dust collection and recovery chamber.

5. A particle coating apparatus according to claim 1, A particle coating apparatus comprising a dust collection and recovery chamber equipped with a heating unit for heating the collected powder to be processed.

6. A particle coating apparatus according to claim 1, The aforementioned processing room is Multiple trays for holding powder layers, in which the powder to be processed is laid out in layers, A mounting section on which the aforementioned multiple trays are placed in a removable manner, A particle coating apparatus having the following features.

7. A particle coating apparatus according to claim 1, The reaction gas is oxygen gas. The processing chamber is a particle coating apparatus having a plasma generation unit that generates oxygen plasma using the oxygen gas.

8. A particle coating method for forming a coating film on the surface of a powder to be treated by atomic layer deposition, A step of placing the powder to be processed into the processing chamber through the opening and closing part of the processing chamber, The process of supplying raw material gas into the aforementioned processing chamber, After the step of supplying the raw material gas, or simultaneously with the step of supplying the raw material gas, a first exhaust step is performed in which a suction pump is operated via a dust collection and recovery chamber communicating with the processing chamber to exhaust the raw material gas and the powder to be processed contained in the raw material gas from the processing chamber to the dust collection and recovery chamber. The process of supplying reaction gas into the aforementioned processing chamber, After the step of supplying the reaction gas, or simultaneously with the step of supplying the reaction gas, a second exhaust step is performed in which the suction pump is operated via the dust collection chamber to exhaust the reaction gas and the powder to be processed contained in the reaction gas from the processing chamber to the dust collection chamber. It has, A particle coating method comprising the first exhaust step and the second exhaust step, wherein the first exhaust step and the second exhaust step recover the powder to be treated contained in the raw material gas and the powder to be treated contained in the reaction gas using a dust collection and recovery mechanism provided in the dust collection and recovery chamber.

9. A particle coating method according to claim 8, A particle coating method comprising the steps of heating the powder to be treated, which has been collected in the dust collection chamber, for the first exhaust step and the second exhaust step.

10. A particle coating method according to claim 8, The dust collection and recovery mechanism is a cyclone type particle coating method.

11. A particle coating method according to claim 8, The dust collection and recovery mechanism is a particle coating method using a glow discharge method.

12. A particle coating method according to claim 8, The powder to be treated is composed of a soft magnetic metal material. The aforementioned coating is made of an insulating material, and the particle coating method is as described above.

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