Particle coating film thickness recording unit, particle coating device and particle coating film thickness management method

Abstract

To provide a particle coating film thickness recording unit capable of recording variance in film thickness of a coating deposited on a surface of a particle, a particle coating device, and a particle coating film thickness management method capable of controlling the variance in film thickness of the coating based upon a film thickness of the coating recorded by a particle coating film thickness measurement unit.SOLUTION: The present invention relates to a particle coating film thickness recording unit which is arranged in a film deposition chamber for depositing a coating on a particle by an atomic layer deposition method and used to record a film thickness of the coating, and the particle coating film thickness recording unit comprises: a container which has a first recessed storage part where a porous structure is stored; a deep layer film thickness recording part which is arranged more on a bottom surface side of the first storage part than the porous structure, and serves to deposit the coating with a raw material gas and an oxidizer penetrating the porous structure by the atomic layer deposition method; and a surface layer film thickness recording part which is arranged outside the first storage part, and serves to deposit the coating.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a particle coating thickness recording unit, a particle coating device, and a particle coating thickness control method. [Background technology]

[0002] For magnetic powders used in inductors, etc., it is necessary to apply an insulating treatment to the particle surface to suppress eddy currents flowing between particles and to insulate terminals. For this reason, methods for forming insulating coatings on the particle surfaces of magnetic powders using various film-forming methods are being investigated.

[0003] For example, Patent Document 1 discloses a particle coating device that forms an insulating film on the surface of soft magnetic metal particles by atomic layer deposition (ALD), a type of chemical vapor deposition method. Atomic layer deposition makes it possible to form an insulating film that is thin and uniform in thickness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-085050 Summary of the Invention [Problem to be solved by the invention]

[0005] In the particle coating device described in Patent Document 1, soft magnetic metal particles are placed in a tray to form a coating. The tray holds the soft magnetic metal particles in a layered state. In atomic layer deposition, raw materials and an oxidizing agent penetrate into the gaps between the particles to form a coating.

[0006] However, there is a difference in the thickness of the coating between the surface portion and the portion located at the bottom of the tray in the layer of soft magnetic metal particles. If this difference becomes large, the film thickness will vary greatly, which may result in an insufficient coating thickness, leading to poor insulation, or an excessive coating thickness, leading to a decrease in the space factor of the soft magnetic metal particles.

[0007] Therefore, there is a need for a method for controlling the variation in the coating thickness and a means for recording the variation in the coating thickness. [Means for solving the problem]

[0008] The particle coating thickness recording unit according to the application example of the present invention comprises: A particle coating thickness recording unit disposed in a film formation chamber for forming a film on a particle by an atomic layer deposition method, the particle coating thickness recording unit being used to record a film thickness, a container having a first recessed storage portion in which the porous structure is stored; a deep layer thickness recording section disposed closer to the bottom of the first storage section than the porous structure and used for forming a coating using a source gas and an oxidizing agent that have permeated the porous structure in an atomic layer deposition method; a surface layer thickness recording unit disposed outside the first housing unit and used for forming a coating; Equipped with.

[0009] A particle coating apparatus according to an application example of the present invention includes: A particle coating apparatus for forming a coating on a surface of a particle by atomic layer deposition, a deposition chamber containing the particles; a particle coating film thickness recording unit according to an application example of the present invention, which is provided in the film formation chamber; a raw material gas supply unit that supplies a raw material gas into the film formation chamber; an oxidant supply unit that supplies an oxidant into the film formation chamber; Equipped with.

[0010] A particle coating thickness control method according to an application example of the present invention includes: 1. A method for controlling the thickness of a coating formed by atomic layer deposition on a surface of particles contained in a deposition chamber, comprising: placing a particle coating thickness recording unit according to an application example of the present invention and the particles in the film-forming chamber; depositing a coating by atomic layer deposition; measuring the thickness of a coating formed on the deep layer thickness recording portion by the raw material gas and the oxidizing agent that have permeated the porous structure, and the thickness of a coating formed on the surface layer thickness recording portion; It has. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a particle coating apparatus according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an example of coated particles produced by the particle coating apparatus shown in FIG. [Figure 3] FIG. 2 is a partial enlarged view of the particle coating thickness recording unit shown in FIG. 1 after coating formation. [Figure 4] FIG. 2 is a process diagram illustrating a particle coating film thickness control method according to the first embodiment. [Figure 5] FIG. 10 is a cross-sectional view showing a particle coating device and a particle coating film thickness recording unit according to a modified example of the first embodiment. [Figure 6] FIG. 10 is a cross-sectional view showing a particle coating device and a particle coating film thickness recording unit according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing a particle coating device and a particle coating film thickness recording unit according to a third embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing a particle coating device and a particle coating film thickness recording unit according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A particle coating thickness recording unit, a particle coating device, and a particle coating thickness control method according to the present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

[0013] 1. First embodiment First, the first embodiment will be described.

[0014] FIG. 1 is a cross-sectional view showing a particle coating apparatus 1 according to a first embodiment. FIG. 2 is a cross-sectional view schematically showing an example of a coated particle 93 produced by the particle coating apparatus 1 shown in FIG. 1. For ease of explanation, in FIG. 1, three mutually orthogonal axes are set as an X-axis, a Y-axis, and a Z-axis, and each axis is indicated by an arrow. The XY plane is a horizontal plane. The base end of the arrow is referred to as the negative side of each axis, and the tip end is referred to as the positive side of each axis. The positive side of the Z-axis is vertically upward, and the negative side of the Z-axis is vertically downward.

[0015] 1.1.Particle coating equipment The particle coating apparatus 1 shown in Fig. 1 is an apparatus that forms a coating 92 shown in Fig. 2 on the surface of particles 91 by atomic layer deposition (ALD). In the following description, an aggregate of particles 91 will be referred to as "powder to be treated." This particle coating apparatus 1 includes a film-forming chamber 2, a particle coating film thickness recording unit 3 (the particle coating film thickness recording unit according to the first embodiment), a raw material gas supply unit 22, an oxidizing agent supply unit 24, and an exhaust unit 26.

[0016] In the particle coating apparatus 1, particles 91 of the powder to be treated are placed in the film formation chamber 2. After the film formation chamber 2 is evacuated by the exhaust unit 26, the raw material gas supply unit 22 supplies raw material gas G1, and the oxidizing agent supply unit 24 supplies oxidizing agent G2. The particles 91 are placed in the form of an aggregate of particles in the form of a powder layer 90. After the powder layer 90 is placed in the film formation chamber 2, the powder layer 90 is heated by a heating unit (not shown). The raw material gas G1 introduced into the film formation chamber 2 is decomposed, and the decomposition products are adsorbed onto the surfaces of the particles 91, ultimately forming a coating 92 as shown in FIG. 2. This results in coated particles 93 as shown in FIG. 2.

[0017] The film formation chamber 2 is rigid and airtight. The film formation chamber 2 maintains a reduced pressure state by evacuating the interior. Examples of materials that can be used to form the film formation chamber 2 include glass materials such as quartz glass, ceramic materials such as alumina, and metal materials such as stainless steel, aluminum, and titanium.

[0018] 1.2.Particle Coating Thickness Recording Unit FIG. 3 is a partial enlarged view of the particle coating thickness recording unit 3 shown in FIG.

[0019] The particle coating film thickness recording unit 3 shown in FIG. 3 includes a container 30, a deep layer film thickness recording section 42, and a surface layer film thickness recording section 44. The container 30 includes a first storage section 34 that stores a powder layer 90 composed of particles 91. The first storage section 34 is concave and opens toward the positive side of the Z axis. The source gas G1 and oxidizing agent G2 supplied into the deposition chamber 2 during atomic layer deposition permeate the powder layer 90. In this embodiment, the powder layer 90 is used as one form of a "porous structure 32." As described below, the porous structure 32 is a collection of particles 91 on which a coating 92 is formed, i.e., a component simulating the powder layer 90, and includes pores corresponding to the gaps between the particles 91. The volume fraction of the pores in the porous structure 32 affects the thickness of the coating 92 formed on the particles 91 that constitute the powder layer 90. Although the porous structure 32 may be made of a material other than the powder layer 90, in this embodiment, the powder layer 90 itself constitutes the porous structure 32.

[0020] The deep layer film thickness recording unit 42 is disposed on the bottom surface 342 side of the first storage unit 34. A coating 422 similar to the coating 92 is formed on the deep layer film thickness recording unit 42 by the source gas G1 and oxidizer G2 that have permeated through the powder layer 90. In other words, the powder layer 90 (porous structure 32) provides the deep layer film thickness recording unit 42 with a film formation environment equivalent to the film formation environment in the deep layer DL of the powder layer 90, such as the concentrations and exposure time of the source gas G1 and oxidizer G2. Therefore, the film thickness of the coating 422 formed on the deep layer film thickness recording unit 42 reflects the film thickness of the coating 92 formed on the particles 91 located in the deep layer DL of the powder layer 90. In particular, in this embodiment, because the powder layer 90 itself constitutes the porous structure 32, the film thickness of the coating 422 formed on the deep layer film thickness recording unit 42 reflects with high accuracy the film thickness of the coating 92 formed on the particles 91 located in the deep layer DL. The particles 91 located in the deep layer DL refer to particles 91 that are exposed on the surface of the powder layer 90 on the negative side of the Z axis.

[0021] The surface layer film thickness recording unit 44 is disposed outside the first storage unit 34. A coating 442 similar to the coating 92 is formed on the surface layer film thickness recording unit 44 using a source gas G1 and an oxidizing agent G2 that do not permeate the powder layer 90. The thickness of the coating 442 reflects the thickness of the coating 92 formed on the particles 91 located on the surface layer SL of the powder layer 90. The particles 91 located on the surface layer SL refer to the particles 91 exposed on the surface of the powder layer 90 on the positive side of the Z axis.

[0022] When the particle coating thickness recording unit 3 shown in FIG. 3 is used for atomic layer deposition, the source gas G1 and the oxidizing agent G2 penetrate into the gaps between the particles 91 and the gaps between the particles 91 and the first storage compartment 34. Then, a coating 92 is formed on the particles 91 located in the deep layer DL and the surface layer SL of the powder layer 90. Because the penetration distances of the source gas G1 and the oxidizing agent G2 differ between the deep layer DL and the surface layer SL, the thickness of the coating 92 also differs. Therefore, the particle coating thickness recording unit 3 records the thickness of the coating 422 formed in the deep layer thickness recording section 42 and the thickness of the coating 442 formed in the surface layer thickness recording section 44. If the thickness of the coating 92 varies, the thickness of the coating 422 reflects the minimum value or its vicinity. The thickness of the coating 442 reflects the maximum value or its vicinity. Therefore, it is highly likely that the thickness of coating 92 falls between the thickness of coating 422 and the thickness of coating 442. Therefore, based on the thickness recorded using particle coating thickness recording unit 3, it is possible to appropriately grasp (manage) the variation in the thickness of coating 92 without actually measuring the thickness of coating 92. Furthermore, the grasped variation in thickness can also be used as inspection data for coated particles 93.

[0023] The particle coating apparatus 1 includes one or more particle coating thickness recording units 3 housed in a film formation chamber 2. In FIG. 1, three particle coating thickness recording units 3 are stacked in the Z-axis direction in the film formation chamber 2. By stacking multiple particle coating thickness recording units 3 in the film formation chamber 2, the space in the film formation chamber 2 can be used effectively, and many coated particles 93 can be produced in a single film formation process. The particle coating thickness recording unit 3 will be described in more detail below.

[0024] 1.2.1. Container 3 is a plate-like container extending in the XY plane. The container 30 has a first container 34 for containing the powder layer 90, a second container 36 for containing the surface layer thickness recording unit 44, and a third container 38 for containing the deep layer thickness recording unit 42.

[0025] The first storage section 34 is a concave space (concave opening on the positive side of the Z axis) that opens on the upper surface of the container 30. Because the first storage section 34 has a flat shape that spreads along the XY plane, a powder layer 90 in which the powder to be processed is thinly spread can be easily formed by using a squeegee or the like (not shown).

[0026] 1, the maximum length of the first storage section 34 in the XY plane is designated as L. The maximum length L of the first storage section 34 is set appropriately depending on the volume of the film formation chamber 2, the particle size of the particles 91, and the like, but is preferably 30 mm or more and 1000 mm or less, and more preferably 100 mm or more and 500 mm or less. This allows many coated particles 93 to be produced in a single film formation process, and also reduces variations in the film thickness of the coating 92.

[0027] 1, the maximum depth of the first storage section 34 in the Z-axis direction is designated as t1. The maximum depth t1 of the first storage section 34 is set appropriately depending on the volume of the film formation chamber 2, the particle size of the particles 91, and the like, but is preferably 1 mm or more and 10 mm or less, and more preferably 3 mm or more and 8 mm or less. This allows many coated particles 93 to be produced in a single film formation process, and also reduces variations in the film thickness of the coating 92.

[0028] The second storage section 36 is provided at a position adjacent to the first storage section 34, and is a concave space (a concave space that is open on the positive side of the Z axis) that is open to the upper surface of the container 30. Note that, although the second storage section 36 is shown in Fig. 3 as a concave space with a bottom, the second storage section 36 may be a space that penetrates in the Z axis direction.

[0029] The second container 36 contains a surface layer thickness recording unit 44. The surface layer thickness recording unit 44 shown in FIG. 3 has a film-forming surface 440 on which a coating 442 is formed. The film-forming surface 440 is preferably set to be flush with or near the top surface of the container 30. Nearby refers to, for example, a deviation of 3 mm or less in the Z-axis direction. This allows the top surface of the powder layer 90 and the film-forming surface 440 to be aligned on the same plane when the powder layer 90 is formed in the first container 34 using a squeegee (not shown). As a result, the thickness of the coating 442 formed on the surface layer thickness recording unit 44 can more faithfully reflect the thickness of the coating 92 formed on the surface layer SL of the powder layer 90. Furthermore, by using a container 30 having the second container 36, the particle coating thickness recording unit 3 can be easily manufactured simply by placing the surface layer thickness recording unit 44 in the second container 36.

[0030] The opening of the second storage section 36 is preferably located in the same plane as the opening of the first storage section 34. This makes it easier to align the upper surface of the powder layer 90 and the film formation surface 440 in the same plane when the surface layer film thickness recording section 44 is stored in the second storage section 36.

[0031] The third accommodating section 38 is a recessed space that opens to the bottom surface 342 of the first accommodating section 34. Although the third accommodating section 38 is shown in Fig. 3 as a recessed space with a bottom, the third accommodating section 38 may be a space that penetrates in the Z-axis direction.

[0032] The third storage compartment 38 accommodates a deep layer thickness recording unit 42. Because the third storage compartment 38 is open to the bottom surface 342, the deep layer thickness recording unit 42 is positioned closer to the bottom surface 342 of the first storage compartment 34 than the powder layer 90 (porous structure 32). The deep layer thickness recording unit 42 shown in FIG. 3 has a film formation surface 420 on which a coating 422 is formed. The film formation surface 420 is preferably set to be flush with or near the bottom surface 342. Nearby refers to, for example, a deviation of 3 mm or less in the Z-axis direction. This allows the lower surface of the powder layer 90 and the film formation surface 420 to be aligned on the same plane. As a result, the film thickness of the coating 422 formed on the deep layer thickness recording unit 42 can more faithfully reflect the film thickness of the coating 92 formed in the deep layer DL of the powder layer 90. Furthermore, by using the container 30 having the third storage portion 38, particles k3 can be easily produced simply by placing the deep layer thickness recording portion 42 in the third storage portion 38.

[0033] Examples of materials constituting the container 30 include metal materials such as stainless steel, aluminum alloy, magnesium alloy, copper alloy, and titanium alloy, ceramic materials such as silica and alumina, glass materials, carbon materials, and resin materials. Also, the container 30 may be made of a composite material that combines two or more of these materials.

[0034] Metallic materials are particularly preferred as the constituent material of the container 30, and stainless steel is more preferred. This allows for a thin container 30 with sufficient rigidity. As a result, containers 30 that can be stacked at high density in the Z-axis direction are obtained.

[0035] 1.2.2. Deep layer thickness recording section The deep layer film thickness recording unit 42 is preferably disposed in a position in contact with the back surface (the surface on the bottom surface 342 side) of the powder layer 90. The deep layer film thickness recording unit 42 shown in FIG. 3 is a substrate B having a flat surface as the film formation surface 420. The substrate B refers to a member of any shape having a flat surface. Examples of the substrate B include a plate material, a block material, and the like. As described above, a coating 422 having a thickness equivalent to that of the coating 92 formed in the deep layer DL is formed on the flat surface (film formation surface 420) of the substrate B. By measuring the thickness of this coating 422, the thickness of the coating 92 formed in the deep layer DL can be accurately estimated without collecting the coated particles 93. Furthermore, the substrate B is easy to mass-produce and inexpensive. Therefore, even if the deep layer film thickness recording unit 42 is disposable, cost increases can be suppressed.

[0036] Examples of the material for the base material B include metal materials, ceramic materials, glass materials, silicon materials, carbon materials, resin materials, etc. Also, the base material B may be a composite material made by combining two or more of these materials.

[0037] The constituent material of the substrate B preferably contains silicon. Substrate B containing silicon is easy to obtain, and processing techniques are widespread, so a smooth, flat surface can be easily formed. This makes it possible to realize a deep layer film thickness recording unit 42 that can measure the film thickness of the coating 422 with greater accuracy. The silicon may be single crystal silicon, polycrystalline silicon, or amorphous silicon, but single crystal silicon is particularly preferred. In other words, the substrate B is preferably a silicon wafer. This particularly enhances the smoothness of the flat surface, making it possible to realize a deep layer film thickness recording unit 42 that can record the film thickness of the coating 422 with high accuracy.

[0038] The thickness of the substrate B is not particularly limited, but is preferably 100 μm or more and 5000 μm or less, and more preferably 200 μm or more and 1000 μm or less, which allows for easy handling and realization of a deep layer thickness recording portion 42 with appropriate rigidity.

[0039] Furthermore, the deep layer thickness recording unit 42 may have a case that accommodates the above-mentioned substrate B. This allows the deep layer thickness recording unit 42 to be placed in or removed from the third accommodation unit 38 while holding the case, making it easier to handle the deep layer thickness recording unit 42 than when the substrate B is used alone.

[0040] 1.2.3. Surface layer thickness recording section The surface layer film thickness recording unit 44 is preferably disposed in the same plane as the surface of the powder layer 90 (the surface opposite the bottom surface 342). The surface layer film thickness recording unit 44 shown in FIG. 3 is a substrate B having a flat surface as a film-forming surface 440. The substrate B is similar to the deep layer film thickness recording unit 42. As described above, a coating 442 having a thickness equivalent to that of the coating 92 formed on the surface layer SL is formed on the flat surface (film-forming surface 440) of the substrate B. By measuring the film thickness of this coating 442, it is possible to accurately estimate the film thickness of the coating 92 formed on the surface layer SL without collecting coated particles 93. Furthermore, the substrate B is easy to mass-produce and inexpensive. Therefore, even if the surface layer film thickness recording unit 44 is disposable, cost increases can be suppressed.

[0041] Furthermore, the surface layer film thickness recording unit 44 may have a case that accommodates the above-mentioned substrate B. This allows the surface layer film thickness recording unit 44 to be placed in or removed from the second accommodation unit 36 ​​while the case is being held, making the surface layer film thickness recording unit 44 even easier to handle than when the surface layer film thickness recording unit 44 is composed of substrate B alone.

[0042] 1.2.4. Source gas supply section, oxidant supply section, and exhaust section A raw material gas supply unit 22 and an oxidizing agent supply unit 24 are connected to the film formation chamber 2. The raw material gas supply unit 22 supplies the raw material gas G1 required for forming the coating 92 into the film formation chamber 2 and adjusts the partial pressure of the raw material gas G1 within the film formation chamber 2. The raw material gas supply unit 22 includes, for example, a raw material gas reservoir, piping, a flow rate control valve, etc. The oxidizing agent supply unit 24 supplies the oxidizing agent G2 required for forming the coating 92 into the film formation chamber 2 and adjusts the partial pressure of the oxidizing agent G2 within the film formation chamber 2. The oxidizing agent supply unit 24 includes, for example, an oxidizing agent reservoir, piping, a flow rate control valve, etc. The raw material gas G1 and the oxidizing agent G2 are supplied together with a carrier gas containing an inert gas, such as nitrogen gas or argon gas, as necessary.

[0043] The exhaust unit 26 exhausts the air from the film formation chamber 2. This reduces the pressure inside the film formation chamber 2. The exhaust unit 26 includes, for example, a vacuum pump, a pressure gauge, piping, an exhaust valve, and the like.

[0044] 1.3. Powder to be treated Next, the powder to be treated will be described.

[0045] The coated particle 93 shown in FIG. 2 has a particle 91 of the powder to be treated and a coating 92 . The constituent material of the particles 91 (constituent material of the powder to be processed) is not particularly limited, but examples include metal materials, ceramic materials, glass materials, silicon materials, carbon materials, and resin materials. Among these, the constituent material of the particles 91 may be a soft magnetic metal material. When particles 91 made of a soft magnetic metal material are used in magnetic elements such as inductors, insulation between the particles 91 must be ensured. By using the particle coating apparatus 1 described above, a coating 92 with a sufficiently thin film thickness and a high coverage rate can be formed. This results in coated particles 93 that can improve the magnetic properties and insulating properties of the magnetic element. Furthermore, the coating 92 formed by atomic layer deposition is dense, which contributes to realizing a high space factor of the soft magnetic metal material and coated particles 93 with high insulating properties.

[0046] Examples of soft magnetic metal materials include various Fe-based alloys such as pure iron, Fe-Si-based alloys such as silicon steel, Fe-Ni-based alloys such as Permalloy, Fe-Co-based alloys such as Permendur, Fe-Si-Al-based alloys such as Sendust, and Fe-Cr-Si-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.

[0047] The average particle size D50 of particles 91 is not particularly limited, but is preferably 0.1 μm or more and 50.0 μm or less, more preferably 0.5 μm or more and 10.0 μm or less, and even more preferably 1.0 μm or more and 3.5 μm or less. The average particle size D50 of particles 91 is determined as the particle size at which the cumulative amount from the smallest diameter side reaches 50% in the cumulative particle size distribution on a volume basis obtained by laser diffraction method.

[0048] 1.4. Particle coating film thickness control method Next, a particle coating film thickness control method according to the first embodiment will be described. In the following description, a method using a particle coating apparatus 1 shown in Fig. 1 and a particle coating film thickness recording unit 3 shown in Fig. 3 will be described as an example.

[0049] FIG. 4 is a process diagram for explaining the particle coating film thickness control method according to the first embodiment. The particle coating film thickness control method shown in FIG. 4 includes a preparation step S102, a film formation step S104, a film thickness measurement step S106, and a film formation condition change step S108.

[0050] 1.4.1. Preparation Steps In preparation step S102, particles 91 are supplied to the first container 34 of the particle coating thickness recording unit 3 to form a powder layer 90 as shown in Fig. 3. Note that the powder layer 90 may be subjected to pretreatment prior to the formation of a coating 92, which will be described later. Examples of pretreatment include ozone treatment, radical treatment, ultraviolet treatment, plasma treatment, corona treatment, drying treatment, and solvent treatment.

[0051] Furthermore, the surface layer thickness recording section 44 is disposed in the second housing section 36 of the particle coating layer thickness recording unit 3, and the deep layer thickness recording section 42 is disposed in the third housing section 38.

[0052] 1.4.2. Film formation step In the film-forming step S104, the particle coating film thickness recording unit 3 on which the powder layer 90 has been formed is placed in the film-forming chamber 2. Then, in the film-forming chamber 2, a film 92 is formed on the powder layer 90 by atomic layer deposition. The film 92 is formed, for example, as follows.

[0053] First, the powder layer 90 is heated. This heating may be performed in a time-overlapping manner with the formation of the coating 92, which will be described later, or may be performed separately from the film formation, i.e., without overlapping in time. Furthermore, heating of the powder layer 90 may be performed as needed, and may be omitted.

[0054] The heating temperature is not particularly limited, but is preferably 30° C. or higher and 500° C. or lower, and more preferably 80° C. or higher and 300° C. or lower. The heating time at such a heating temperature is set appropriately depending on the film thickness of the coating 92, but is preferably 0.1 hours or higher and 300 hours or lower, more preferably 1 hour or higher and 200 hours or lower, and even more preferably 5 hours or higher and 100 hours or lower.

[0055] The pressure in the film formation chamber 2 before introducing the source gas G1 and the oxidizing agent G2 is not particularly limited, but is preferably 10 kPa or less, and more preferably 1 kPa or less. This makes it possible to suppress residual oxygen and moisture in the film formation chamber 2. The lower limit of the pressure in the film formation chamber 2 does not need to be particularly set, but taking into consideration the increased cost of maintaining a reduced pressure state and the possibility that the effects of reducing the pressure may not be fully obtained, it is preferable to set the lower limit to 1×10 -5 Pa or more, and 1×10 -3 It is more preferable that the temperature is 1000 Pa or more.

[0056] Next, the raw material gas G1 is introduced into the film formation chamber 2 by the raw material gas supply unit 22. The introduced raw material gas G1 is adsorbed onto the surfaces of the particles 91. At this time, once the raw material gas G1 is adsorbed onto the surfaces of the particles 91, it is difficult for it to be further adsorbed into multiple layers. This makes it possible to control the film thickness of the coating 92 that is ultimately obtained with high precision. The raw material gas G1 also gets around and adsorbs into shaded and gap areas. However, as mentioned above, there is often a difference in film thickness of the coating 92 that is ultimately obtained between the surface layer SL and the deep layer DL of the powder layer 90.

[0057] The source gas G1 may be, for example, a gas containing a precursor of the coating 92. Specifically, when forming a silicon oxide-based coating 92, examples of the source gas G1 include dimethylaminosilane, methylethylaminosilane, diethylaminosilane, trisdimethylaminosilane, bisdiethylaminosilane, and bistertiarybutylaminosilane.

[0058] Examples of materials constituting the formed coating 92 include silicon oxide, as well as oxides such as hafnium oxide, tantalum oxide, titanium oxide, and chromium oxide, and nitrides such as aluminum nitride, titanium nitride, and tantalum nitride.

[0059] Next, the source gas G1 in the film formation chamber 2 is exhausted by the exhaust unit 26, and then an inert gas such as nitrogen or argon is introduced as necessary.

[0060] Next, the inert gas inside the film formation chamber 2 is discharged by the exhaust unit 26, and then the oxidizing agent G2 is introduced into the film formation chamber 2 by the oxidizing agent supply unit 24. Examples of the oxidizing agent G2 include ozone, plasma oxygen, and water vapor.

[0061] The oxidizing agent G2 reacts with the source gas G1 adsorbed on the surface of the particles 91 to form a coating 92. Like the source gas G1, the oxidizing agent G2 also finds its way into shaded areas and gaps.

[0062] Next, the oxidizing agent G2 in the film-forming chamber 2 is discharged by the exhaust unit 26, and then an inert gas is introduced, if necessary, to replace the oxidizing agent G2. In this manner, the coating 92 is formed, and coated particles 93 are obtained.

[0063] The introduction and discharge of the source gas G1 and the introduction and discharge of the oxidizing agent G2 may be repeated depending on the target film thickness of the film 92. The film thickness can be increased depending on the number of repetitions.

[0064] Thereafter, if necessary, post-treatment may be performed on the coated particles 93. Examples of post-treatment include static elimination treatment and radical treatment.

[0065] The thickness of the coating 92 is not particularly limited, but is preferably 1 nm to 500 nm, more preferably 2 nm to 300 nm, and even more preferably 4 nm to 200 nm. Such a thickness allows the coating 92 to be formed uniformly in a relatively short time. Furthermore, atomic layer deposition allows the formation of a dense coating 92, so that even a thin coating 92 has sufficient insulating properties. This results in a coating 92 with excellent insulating properties. The thickness of the coating 92 is the average of measurements taken at five or more locations by enlarging and observing the cross section of the coated particle 93.

[0066] The formation of the coating 92 as described above is carried out while the powder layer 90 is left standing, so that the coating 92 can be formed with a uniform thickness.

[0067] 1.4.3. Film Thickness Measurement Step In the film thickness measurement step S106, first, the particle coating film thickness recording unit 3 is removed from the film formation chamber 2. Then, the particle coating film thickness recording unit 3 is tilted or the like to recover the coated particles 93.

[0068] Also, the deep layer film thickness recording unit 42 and the surface layer film thickness recording unit 44 are removed. Then, the film thickness of the coating 422 formed on the deep layer film thickness recording unit 42 and the film thickness of the coating 442 formed on the surface layer film thickness recording unit 44 are measured, respectively.

[0069] Examples of methods for measuring the thickness of the coatings 422 and 442 include a method using optical interference, a method using cross-section observation, a method using a spectrophotometer, and X-ray reflectance analysis. Of these, the method using optical interference is preferred. This method allows for easy measurement of the thickness, contributing to a reduction in the number of steps required for controlling the thickness of a particle coating.

[0070] As described above, the measured thickness of the coating 422 reflects the minimum value or its vicinity of the thickness of the coating 92 formed on the powder layer 90. Furthermore, as described above, the measured thickness of the coating 442 reflects the maximum value or its vicinity of the thickness of the coating 92 formed on the powder layer 90. Therefore, the range of the thickness of the coating 92 can be estimated based on these minimum and maximum thickness values. This allows the variation in the thickness of the coating 92 to be more easily and accurately recorded and understood (managed). The understood variation in thickness can also be used as inspection data for the coated particles 93. Furthermore, the particle coating thickness recording unit 3 shown in FIG. 3 uses the powder layer 90 as the porous structure 32. Therefore, compared to using a material other than the powder layer 90 as the porous structure 32, this has the advantage of reducing the discrepancy between the thickness of the coating 422 and the thickness of the coating 92 formed in the deep layer DL.

[0071] 1.4.4. Film formation condition change step In the film-forming condition change step S108, the recorded variation in the thickness of the coating 92 is reflected in the manufacturing conditions for the next production of coated particles 93. Specifically, the film-forming conditions are changed so that the thickness of the coating 422 formed in the deep layer film thickness recording unit 42 and the thickness of the coating 442 formed in the surface layer film thickness recording unit 44 fall within a predetermined range. These film-forming conditions are applied to the next production of coated particles 93. Examples of changes to the film-forming conditions include increasing the concentrations of the source gas G1 and the oxidizer G2 or lengthening the time for supplying these gases. Such changes can increase the amount of source gas G1 and oxidizer G2 that reaches the deep layer DL of the powder layer 90. This can increase the thickness of the coating 92 formed in the deep layer DL. As a result, variation in the thickness of the coating 92 can be further suppressed, allowing for the efficient production of higher-quality coated particles 93.

[0072] The film formation condition changing step S108 may be performed as needed and may be omitted.

[0073] 2. Variations Next, a modification of the first embodiment will be described.

[0074] FIG. 5 is a cross-sectional view showing a particle coating apparatus 1 and a particle coating film thickness recording unit 3 according to a modified example of the first embodiment.

[0075] The following describes the modified example, focusing on the differences from the first embodiment, and omitting the description of the similarities. Note that in Fig. 5, the same reference numerals are used to designate the same components as those in the first embodiment.

[0076] The particle coating film thickness recording unit 3 according to the modified example is similar to the particle coating film thickness recording unit 3 according to the first embodiment, except that the surface layer film thickness recording section 44 has a QCM sensor element Q. Furthermore, the particle coating device 1 according to the modified example is similar to the particle coating device 1 according to the first embodiment, except for the above-mentioned differences.

[0077] The QCM sensor element Q constituting the surface layer thickness recording unit 44 shown in Figure 5 is a quartz crystal microbalance sensor element that monitors film thickness based on the frequency of the quartz crystal, which changes depending on the thickness of the film formed on the quartz crystal. The QCM sensor element Q includes, for example, a quartz crystal blank and electrodes on both sides of the quartz crystal blank. When a voltage that changes at a predetermined frequency is applied between the electrodes, the QCM sensor element Q vibrates in response to the change in voltage. When a film is formed on the QCM sensor element Q in this state, the frequency decreases depending on the film thickness. The film thickness can be calculated in real time based on the magnitude of this decrease.

[0078] The QCM sensor element Q is connected to wiring (not shown). This wiring is routed to the outside of the film formation chamber 2 without compromising the airtightness of the film formation chamber 2. This allows the thickness of the film 442 being formed to be monitored in real time, making it possible to control the film thickness by, for example, stopping film formation when the target film thickness is reached. Therefore, not only can the variation in the film thickness of the film 92 be controlled, but the film thickness itself can also be controlled.

[0079] In the above-described modified example, the same effects as in the first embodiment can be obtained. In this modification, the deep layer film thickness recording unit 42 may also be configured with the QCM sensor element Q. This allows the film thickness of the coating 422 to be monitored in real time during film formation. In this case, a member for preventing contact between the powder layer 90 and the QCM sensor element Q, such as a mesh that prevents the powder layer 90 from passing through, may be used.

[0080] 3. Second embodiment Next, a second embodiment will be described.

[0081] FIG. 6 is a cross-sectional view showing a particle coating apparatus 1 and a particle coating film thickness recording unit 3 according to the second embodiment.

[0082] The second embodiment will be described below, focusing on the differences from the first embodiment and omitting the description of the similarities. Note that in Fig. 6, the same reference numerals are used to designate the same components as those in the first embodiment.

[0083] The particle coating film thickness recording unit 3 according to the second embodiment is similar to that according to the first embodiment, except that its size in the XY plane is smaller than that according to the first embodiment, and that it is used together with a powder tray 5. Furthermore, the particle coating apparatus 1 according to the second embodiment is similar to the particle coating apparatus 1 according to the first embodiment, except for the above-mentioned differences.

[0084] In the first embodiment described above, the particle coating thickness recording unit 3 has the first container 34 with a sufficient capacity, and the powder layer 90 is formed in this first container 34.

[0085] In contrast to this, in the second embodiment, a powder tray 5 having a recess 51 with sufficient volume is housed in the film formation chamber 2, separate from the particle coating film thickness recording unit 3. Then, a powder layer 90 is formed in this recess 51, while the size of the first housing portion 34 of the particle coating film thickness recording unit 3 is equal to or slightly larger than the size of the deep layer film thickness recording portion 42.

[0086] A powder layer 95 is formed in the first storage section 34 of the particle coating film thickness recording unit 3 shown in FIG. 6. The powder layer 95 is formed by spreading particles 91 in a layer. Therefore, in this embodiment, the powder layer 95 provided separately from the powder layer 90 constitutes the porous structure 32. This powder layer 95 can provide the deep layer film thickness recording section 42 with a film formation environment equivalent to the film formation environment in the deep layer DL of the powder layer 90 provided in the powder tray 5. This function of the porous structure 32 is similar to that of the particle coating film thickness recording unit 3 according to the first embodiment.

[0087] 6, the particle coating film thickness recording unit 3 is configured such that the powder tray 5 that stores the powder layer 90 is separate from the particle coating film thickness recording unit 3, allowing for free selection of the relative position of the particle coating film thickness recording unit 3 with respect to the powder tray 5. This allows the particle coating film thickness recording unit 3 to be positioned, for example, at a position where the film thickness of the coating 92 is likely to be thin or thick, thereby enabling more accurate recording of variations in the film thickness of the coating 92.

[0088] In order to accurately reflect the thickness of the coating 422 formed in the deep layer thickness recording section 42 with the thickness of the coating 92 formed in the deep layer DL of the powder layer 90, the size of the first storage section 34 only needs to be equal to or larger than the size of the deep layer thickness recording section 42. Therefore, in this embodiment, the container 30 of the particle coating thickness recording unit 3 can be prevented from becoming too large.

[0089] On the other hand, in the particle coating film thickness recording unit 3 shown in Fig. 6, a powder layer 90 is accommodated in a recess 51 of a powder tray 5. Then, by atomic layer deposition, a coating 92 shown in Fig. 2 is formed on particles 91 in the powder layer 90. If the recess 51 has a sufficient volume, a large number of coated particles 93 shown in Fig. 2 can be produced in a single film formation process, even in the second embodiment.

[0090] The maximum depth of the recess 51 in the Z-axis direction is defined as t2. The maximum depth t2 of the recess 51 is the same as the maximum depth t1 of the first accommodating portion 34 in the first embodiment.

[0091] In the second embodiment, the maximum depth of the first storage portion 34 in the Z-axis direction is defined as t3. The maximum depth t3 of the first storage portion 34 may be different from the maximum depth t2 of the recess 51, but is preferably the same. "The same" means that when the maximum depth t2 is defined as 1, the maximum depth t3 is 0.8 or more and 1.2 or less. This allows the powder layer 95 stored in the first storage portion 34 to provide the deep layer film thickness recording unit 42 with a film formation environment that is closer to the film formation environment in the deep layer DL of the powder layer 90.

[0092] The particle coating thickness recording unit 3 may be located at a different height (position in the Z-axis direction) from the powder tray 5, but is preferably located close to the powder tray 5. "Close" refers to a distance of 50 mm or less in the Z-axis direction. By locating the particle coating thickness recording unit 3 at such a position, the thickness of the coating 92 formed on the powder layer 90 can be recorded with greater accuracy.

[0093] Furthermore, since the particle coating film thickness recording unit 3 according to the second embodiment is smaller than the powder tray 5, it is also possible to arrange a plurality of particle coating film thickness recording units 3 for one powder tray 5. This allows the particle coating film thickness recording unit 3 to record, for example, not only the variation in film thickness of the coating 92 in the thickness direction (Z-axis direction) of the powder layer 90, but also the variation in film thickness of the coating 92 in the in-plane direction (XY plane) of the powder layer 90. In the second embodiment as described above, the same effects as in the first embodiment can be obtained.

[0094] 4. Third embodiment Next, a third embodiment will be described.

[0095] FIG. 7 is a cross-sectional view showing a particle coating apparatus 1 and a particle coating film thickness recording unit 3 according to the third embodiment.

[0096] The third embodiment will be described below, focusing on the differences from the second embodiment and omitting a description of similarities. Note that in Fig. 7, the same reference numerals are used to designate the same components as those in the second embodiment.

[0097] The particle coating film thickness recording unit 3 according to the third embodiment is similar to the particle coating film thickness recording unit 3 according to the second embodiment, except that a filter F is used as the porous structure 32. Furthermore, the particle coating apparatus 1 according to the third embodiment is similar to the particle coating apparatus 1 according to the third embodiment, except for the above-mentioned differences.

[0098] The filter F shown in FIG. 7 is a member having three-dimensional interconnected pores. This filter F is also used as a member simulating the powder layer 90. The three-dimensional interconnected pores refer to pores that are open on both the top and bottom surfaces of the filter F. The three-dimensional interconnected pores of the filter F mimic the gaps between particles 91 formed in the powder layer 90. Therefore, by using the filter F with three-dimensional interconnected pores, the functionality of the porous structure 32 can be achieved without forming the powder layer 95 shown in FIG. 6. This allows for the realization of a particle coating thickness recording unit 3 that can more easily provide the deep layer thickness recording unit 42 with a film-forming environment equivalent to that in the deep layer DL of the powder layer 90. In other words, by mass-producing particle coating thickness recording units 3 each containing a filter F in the second housing 36 in advance and then simply placing them in the film-forming chamber 2 as needed, the thickness of the coating 92 can be controlled.

[0099] The configuration of the filter F is set appropriately depending on the configuration of the powder layer 90. For example, the porosity (space ratio of pores) of the filter F is set in accordance with the porosity of the powder layer 90. The porosity of the powder layer 90 can be calculated, for example, by the following formula.

[0100] (Porosity of powder layer 90)=1−(bulk density of powder layer 90) / (true density of particles 91)

[0101] The bulk density of the powder layer 90 is calculated by packing the particles 91 into a predetermined container, measuring the weight of the particles 91, and then using the measured weight and the volume of the container. The true density of the particles 91 is the density of the material that constitutes the particles 91.

[0102] The size of the pores that form the three-dimensional interconnected pores of filter F is also set to match the size of the pores in powder layer 90. The size of the pores in powder layer 90 can be calculated from the particle diameter of particles 91 and the porosity of powder layer 90.

[0103] The term "set in accordance with" means to set the same value or to set a value calculated in light of a predetermined correlation. This correlation can be determined through experiments or simulations. The configuration of the filter F may also be set based on parameters other than the porosity, such as the aspect ratio of the pores and the pore size distribution.

[0104] Examples of materials constituting the filter F include metal materials, ceramic materials, glass materials, and resin materials. Of these, metal materials are preferably used. Metal materials have good heat resistance and rigidity. Therefore, by using metal materials, a thermally and mechanically stable filter F can be obtained.

[0105] As the metal material, materials composed of any metal element can be used, but for example, simple substances or alloys of Fe, Cu, Ni, Ti, Al, Mg, etc. are preferably used, as these metal materials are relatively easy to obtain.

[0106] The filter F can be produced by a porous metal production method, such as powder metallurgy, foam melting, powder space holder, fiber space holder, metal fiber compression bonding, foam injection molding, plating, etc.

[0107] For example, in powder metallurgy, the porosity and pore size can be adjusted by controlling the particle size and particle shape of the metal powder used to produce the porous metal, the sintering conditions, and the like.

[0108] The porous metal configuration may also be optimized through experiments or simulations. For example, porous metal samples may be produced by varying parameters such as the particle size and shape of the metal powder, sintering conditions, and the thickness of the porous metal. The reproducibility of the film formation environment using the produced porous metal samples may then be repeatedly evaluated to find a suitable porous metal configuration for the filter F.

[0109] Furthermore, the configuration of the porous metal may be determined using gas permeability as a parameter. The gas permeability of a porous metal is a combined characteristic of the porosity, pore size, thickness of the porous metal, etc. Therefore, porous metals may be prototyped while varying the gas permeability to determine the configuration of the porous metal suitable for Filter F. The gas permeability of a porous metal can be measured using a device for measuring gas barrier properties.

[0110] When the maximum thickness of the filter F is t4, the maximum thickness t4 may be thicker or thinner than the maximum depth t2 of the recess 51. As an example, the maximum thickness t4 is preferably 30% or more and 300% or less of the maximum depth t2 of the recess 51, and more preferably 50% or more and 200% or less. In the third embodiment as described above, the same effects as in the second embodiment can be obtained.

[0111] 5. Fourth embodiment Next, a fourth embodiment will be described.

[0112] FIG. 8 is a cross-sectional view showing a particle coating apparatus 1 and a particle coating film thickness recording unit 3 according to the fourth embodiment.

[0113] The fourth embodiment will be described below, focusing on the differences from the third embodiment and omitting the description of the similarities. Note that in Fig. 8, the same reference numerals are used to designate the same components as those in the third embodiment.

[0114] The particle coating film thickness recording unit 3 of the fourth embodiment is similar to the particle coating film thickness recording unit 3 of the third embodiment, except that it has QCM sensor elements Q as the deep layer film thickness recording section 42 and the surface layer film thickness recording section 44, respectively.

[0115] 8, the thickness of the coating 422 formed on the deep layer thickness recording section 42 and the thickness of the coating 442 formed on the surface layer thickness recording section 44 can be monitored in real time. This makes it possible to control the thickness of the coating 92, such as by stopping the film formation when the target thickness is reached. As a result, the thickness of the coating 92 and its variations can be controlled in real time.

[0116] 8 uses a filter F as the porous structure 32. Therefore, there is no risk of the particles 91 coming into contact with the deep layer film thickness recording section 42, and the film thickness of the film 422 can be recorded with higher accuracy. In the fourth embodiment as described above, the same effects as in the third embodiment can be obtained.

[0117] 6. Effects of the above embodiments As described above, the particle coating film thickness recording unit 3 according to each of the above embodiments and modifications is disposed in a film formation chamber 2 that forms a film 92 on a particle 91 by atomic layer deposition. The particle coating film thickness recording unit is used to record the film thickness of the film 92. The unit includes a container 30, a deep layer film thickness recording unit 42, and a surface layer film thickness recording unit 44. The container 30 has a concave first container 34 that accommodates a porous structure 32. The deep layer film thickness recording unit 42 is disposed closer to the bottom surface 342 of the first container 34 than the porous structure 32 and is used to form a film 422 using a source gas G1 and an oxidizing agent G2 that have permeated the porous structure 32 during atomic layer deposition. The surface layer film thickness recording unit 44 is disposed outside the first container 34 and is used to form the film 442.

[0118] This configuration provides a particle coating thickness recording unit 3 that can record the thickness of the coating 422 formed in the deep layer thickness recording unit 42 and the thickness of the coating 442 formed in the surface layer thickness recording unit 44. This particle coating thickness recording unit 3 can record variations in the thickness of the coating 92 formed on the surface of the particle 91. This allows appropriate management of variations in the thickness of the coating 92 without actually measuring the thickness of the coating 92.

[0119] In the particle coating film thickness recording unit 3 according to each of the above-described embodiments, the porous structure 32 is made up of powder layers 90 and 95 in which particles 91 are spread out.

[0120] According to this configuration, the powder layers 90, 95 provide the deep layer film thickness recording unit 42 with a film formation environment, such as the concentrations and exposure time of the source gas G1 and the oxidizer G2, that is equivalent to the film formation environment in the deep layer DL of the powder layer 90. Furthermore, by using the powder layers 90, 95, the film thickness of the film 422 formed on the deep layer film thickness recording unit 42 reflects with high accuracy the film thickness of the film 92 formed on the particle 91 located in the deep layer DL.

[0121] In the particle coating film thickness recording unit 3 according to each of the above-described embodiments, the deep layer film thickness recording section 42 and the surface layer film thickness recording section 44 have a substrate B having a flat surface.

[0122] According to this configuration, the substrate B can be easily mass-produced and is inexpensive, so that the deep layer film thickness recording section 42 and the surface layer film thickness recording section 44 can be realized without increasing costs even if they are disposable.

[0123] In the particle coating film thickness recording unit 3 according to each of the above-described embodiments, the constituent material of the substrate B contains silicon.

[0124] With this configuration, the substrate B is easy to obtain and has a smooth, flat surface due to the widespread use of processing techniques. This allows for the realization of the deep layer film thickness recording unit 42 and the surface layer film thickness recording unit 44, which can measure the film thicknesses of the coatings 422 and 442 with greater accuracy.

[0125] In the particle coating film thickness recording unit 3 according to each of the above embodiments, when the surface of the powder layer 90, 95 on the bottom surface 342 side is the back surface and the surface opposite the bottom surface 342 side is the front surface, the deep layer film thickness recording section 42 is positioned in contact with the back surface of the powder layer 90, 95, and the surface layer film thickness recording section 44 is positioned in the same plane as the surface of the powder layer 90, 95.

[0126] With this configuration, the thickness of the coating 92 formed in the deep layer DL can be accurately estimated based on the thickness of the coating 422 formed in the deep layer thickness recording unit 42. Also, the thickness of the coating 92 formed in the surface layer SL can be accurately estimated based on the thickness of the coating 442 formed in the surface layer thickness recording unit 44.

[0127] In the particle coating film thickness recording unit 3 according to each of the above-described embodiments, the porous structure 32 is a filter F having three-dimensional continuous pores.

[0128] According to this configuration, it is possible to realize a particle coating film thickness recording unit 3 that can more easily provide the deep layer film thickness recording section 42 with a film formation environment equivalent to the film formation environment in the deep layer DL of the powder layer 90.

[0129] In the particle coating film thickness recording unit 3 according to each of the above-described embodiments, the constituent material of the filter F is a metal material.

[0130] According to this configuration, since the metal material has good heat resistance and rigidity, a thermally and mechanically stable filter F can be obtained.

[0131] In the particle coating film thickness recording unit 3 according to each of the above-described embodiments, the deep layer film thickness recording section 42 and the surface layer film thickness recording section 44 have a QCM sensor element Q.

[0132] With this configuration, the QCM sensor element Q can monitor in real time the thickness of the coating 422 formed in the deep layer thickness recording section 42 and the thickness of the coating 442 formed in the surface layer thickness recording section 44. This enables film thickness control, such as terminating film formation when the target film thickness is reached. As a result, a particle coating film thickness recording unit 3 is obtained that can control the film thickness and its variation in film thickness in real time.

[0133] The particle coating film thickness recording unit 3 according to each of the above embodiments further includes a filter F. This configuration makes it possible to mass-produce particle coating film thickness recording units 3 each having a filter F previously housed in the second housing portion 36. This allows the film thickness of the coating 92 to be controlled simply by placing the particle coating film thickness recording unit 3 in the film-forming chamber 2 at the required timing.

[0134] In the particle coating film thickness recording unit 3 according to each of the above-described embodiments, the container 30 has a concave second storage portion 36 whose opening is flush with the opening of the first storage portion 34. The surface layer film thickness recording portion 44 is stored in the second storage portion 36.

[0135] With this configuration, the particle coating film thickness recording unit 3 can be manufactured simply by placing the surface layer film thickness recording part 44 in the second storage part 36. Furthermore, when the surface layer film thickness recording part 44 is stored in the second storage part 36, the upper surface of the powder layer 90 and the film formation surface 440 of the surface layer film thickness recording part 44 stored in the second storage part 36 can be easily aligned in the same plane.

[0136] The particle coating apparatus 1 according to each of the above embodiments is a particle coating apparatus that forms a coating 92 on the surface of particles 91 by atomic layer deposition, and includes a film formation chamber 2, a particle coating film thickness recording unit 3 according to the above embodiment, a raw material gas supply unit 22, and an oxidizing agent supply unit 24. The film formation chamber 2 accommodates particles 91. The particle coating film thickness recording unit 3 is provided within the film formation chamber 2. The raw material gas supply unit 22 and the oxidizing agent supply unit 24 supply a raw material gas G1 and an oxidizing agent G2 into the film formation chamber 2.

[0137] According to this configuration, it is possible to realize a particle coating apparatus 1 that can appropriately control variations in the thickness of the coating 92 formed on the surface of the particle 91.

[0138] The particle coating apparatus 1 according to each of the above embodiments includes a plurality of particle coating film thickness recording units 3 .

[0139] With this configuration, it is possible to realize a particle coating device 1 that can record not only the variation in the film thickness of the coating 92 in the thickness direction (Z-axis direction) of the powder layer 90, but also the variation in the film thickness of the coating 92 in the in-plane direction (in the XY plane) of the powder layer 90.

[0140] The particle coating film thickness control method according to each of the above embodiments is a method for controlling the film thickness of a film 92 formed by atomic layer deposition on the surface of a particle 91 contained in a film formation chamber 2, and includes a preparation step S102, a film formation step S104, and a film thickness measurement step S106. In the preparation step S102, a particle coating film thickness recording unit 3 according to the above embodiment and the particle 91 are placed in the film formation chamber 2. In the film formation step S104, the film 92 is formed by atomic layer deposition. In the film thickness measurement step S106, the film thickness of a film 422 formed in the deep layer film thickness recording unit 42 by the source gas G1 and oxidizing agent G2 that have permeated the porous structure 32, and the film thickness of a film 442 formed in the surface layer film thickness recording unit 44 are measured.

[0141] According to this configuration, variations in the thickness of the coating 92 can be appropriately controlled without actually measuring the thickness of the coating 92.

[0142] The particle coating film thickness control method according to each of the above embodiments includes a film-forming condition changing step S108. In the film-forming condition changing step S108, the film-forming conditions for the film 92 formed by atomic layer deposition are changed so that the film thickness of the film 422 formed in the deep layer film thickness recording unit 42 and the film thickness of the film 442 formed in the surface layer film thickness recording unit 44 fall within a predetermined range.

[0143] According to this configuration, variations in the thickness of the coating 92 can be further suppressed, and coated particles 93 of higher quality can be efficiently produced.

[0144] Although the particle coating film thickness recording unit, particle coating device, and particle coating film thickness control method according to the present invention have been described above based on the illustrated embodiments, the present invention is not limited to these.

[0145] For example, the particle coating film thickness recording unit and particle coating device according to the present invention may be configured such that each part of each of the above-described embodiments is replaced with any component having the same function, or any component is added to each of the above-described embodiments.Furthermore, the particle coating film thickness control method according to the present invention may be configured such that any desired process is added to each of the above-described embodiments. [Explanation of symbols]

[0146] 1...particle coating device, 2...film formation chamber, 3...particle coating film thickness recording unit, 5...powder tray, 22...raw material gas supply section, 24...oxidizer supply section, 26...exhaust section, 30...container, 32...porous structure, 34...first storage section, 36...second storage section, 38...third storage section, 42...deep layer film thickness recording section, 44...surface layer film thickness recording section, 51...recess, 90...powder layer, 91...particle, 92...coating, 93...coated particle, 95...powder layer, 34 2...bottom surface, 420...film-forming surface, 422...coating, 440...film-forming surface, 442...coating, B...substrate, DL...deep layer, F...filter, G1...source gas, G2...oxidizer, L...maximum length, Q...QCM sensor element, S102...preparation step, S104...film-forming step, S106...film thickness measurement step, S108...film-forming condition change step, SL...surface layer, t1...maximum depth, t2...maximum depth, t3...maximum depth, t4...maximum thickness

Claims

1. A particle coating thickness recording unit disposed in a film formation chamber for forming a film on a particle by an atomic layer deposition method, the particle coating thickness recording unit being used to record a film thickness, a container having a concave first storage portion in which the porous structure is stored; a deep layer thickness recording section disposed closer to the bottom surface of the first storage section than the porous structure and used for forming a coating using a source gas and an oxidizing agent that have permeated the porous structure in an atomic layer deposition method; a surface layer thickness recording unit disposed outside the first housing unit and used for forming a coating; A particle coating thickness recording unit comprising:

2. 2. A particle-coated film thickness recording unit according to claim 1, wherein the porous structure is a powder layer in which the particles are spread over.

3. 3. The particle coating thickness recording unit according to claim 2, wherein the deep layer thickness recording section and the surface layer thickness recording section have a substrate having a flat surface.

4. 4. The particle-coated recording unit according to claim 3, wherein the material of the substrate contains silicon.

5. When the surface of the powder layer on the bottom side is referred to as the back surface and the surface opposite to the bottom side is referred to as the front surface, the deep layer thickness recording unit is disposed at a position in contact with the back surface of the powder layer, 5. The particle coating thickness recording unit according to claim 2, wherein the surface layer thickness recording section is disposed in the same plane as the surface of the powder layer.

6. 2. The particle-coated film thickness recording unit according to claim 1, wherein the porous structure is a filter having three-dimensional interconnected pores.

7. 7. A particle-coated film thickness recording unit according to claim 6, wherein the filter is made of a metal material.

8. 8. The particle coating thickness recording unit according to claim 6, wherein the deep layer thickness recording section and the surface layer thickness recording section each have a QCM sensor element.

9. 8. The particle coating thickness recording unit according to claim 6, further comprising the filter.

10. The container has a second storage portion having an opening in the same plane as the opening of the first storage portion and having a concave shape, 7. The particle coating thickness recording unit according to claim 2, wherein the surface layer thickness recording section is accommodated in the second accommodation section.

11. A particle coating apparatus for forming a coating on a surface of a particle by atomic layer deposition, a deposition chamber containing the particles; a particle coating thickness recording unit according to claim 1 provided in the film-forming chamber; a raw material gas supply unit that supplies a raw material gas into the film formation chamber; an oxidant supply unit that supplies an oxidant into the film formation chamber; A particle coating apparatus comprising:

12. 12. The particle coating apparatus according to claim 11, comprising a plurality of the particle coating film thickness recording units.

13. 1. A method for controlling the thickness of a coating formed by atomic layer deposition on a surface of particles contained in a deposition chamber, comprising: placing the particle coating thickness recording unit according to claim 1 and the particles in the film-forming chamber; depositing a coating by atomic layer deposition; measuring the thickness of a coating formed on the deep layer thickness recording portion by the raw material gas and the oxidizing agent that have permeated the porous structure, and the thickness of a coating formed on the surface layer thickness recording portion; A particle coating thickness control method comprising:

14. 14. The particle coating film thickness control method according to claim 13, further comprising a step of changing the film formation conditions of the film by the atomic layer deposition method so that the film thickness of the film formed in the deep layer film thickness recording portion and the film thickness of the film formed in the surface layer film thickness recording portion fall within a predetermined range.

Images