Production method for boron nitride particles, production method for resin composition, and uses therefor

JPWO2025134475A1Undetermined Publication Date: 2025-06-26
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Patent Information

Application Number
JP2025565073
Authority / Receiving Office
JP · JP
Patent Type
Applications
Priority Date
2023-12-18
Filing Date
2024-10-03
Publication Date
2025-06-26

AI Technical Summary

Technical Problem

Current materials used in high-frequency communication and semiconductor devices face challenges in minimizing dielectric properties and maximizing thermal conductivity, which are essential for reducing transmission loss and efficient heat dissipation.

Method used

A method for producing boron nitride particles involves nitriding boron-containing particles in a nitrogen gas atmosphere under specific conditions of pressure and temperature, resulting in particles with a core-shell structure that exhibits low dielectric properties and high thermal conductivity.

Benefits of technology

The produced boron nitride particles demonstrate improved thermal conductivity and reduced dielectric properties, making them suitable for applications in high-frequency communication systems and semiconductor devices, where they can effectively manage heat dissipation and minimize transmission loss.

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Abstract

The purpose of the present disclosure is to provide: a novel production method for boron nitride particles which is capable of producing boron nitride particles that have a low dielectric property and high thermal conductivity; a production method for a resin composition which includes said method; and uses therefor. A production method for boron nitride particles according to the present disclosure includes a step in which boron-containing particles that contain boron atoms are nitrided in a nitrogen gas atmosphere.
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Description

Method for producing boron nitride particles, method for producing resin composition and applications thereof

[0001] The present disclosure relates to a method for producing boron nitride particles, a method for producing a resin composition, and applications thereof.

[0002] The amount of transmission loss that occurs when radio waves transmitted for communication are converted into heat in a dielectric is expressed as the product of frequency, the square root of the relative dielectric constant, and the dielectric loss tangent. In other words, since the transmission signal is more likely to be converted into heat in proportion to the frequency, the higher the frequency band, the lower the dielectric properties required for communication component materials in order to suppress transmission loss.

[0003] In the field of information and communications, radio waves are becoming increasingly higher in frequency as the number of channels and the amount of information transmitted increase. Currently, studies on fifth-generation mobile communication systems are underway worldwide, and several frequency bands in the range of approximately 30 GHz to 70 GHz have been identified as candidates for use. Furthermore, in sixth-generation mobile communication systems and beyond, frequencies will continue to increase, requiring materials with low dielectric properties to suppress transmission loss.

[0004] Furthermore, high thermal conductivity is required for sealing materials for semiconductor devices, interlayer insulating materials, copper-clad laminates, heat dissipation sheets, and the like.

[0005] Boron nitride is known as an inorganic filler having a low dielectric constant and high thermal conductivity. For example, a granulated powder is known that includes spherical secondary particles formed by agglomerating primary particles, the primary particles being scaly boron nitride, the secondary particles having a core portion including the center of the secondary particle and a shell portion covering the core portion, and the density of the primary particles in the core portion is lower than the density of the primary particles in the shell portion (see, for example, Patent Document 1).

[0006] Patent No. 6413478

[0007] As described above, in the field of semiconductor devices and the like, low dielectric properties and high thermal conductivity are required, and a new manufacturing method capable of producing boron nitride having low dielectric properties and high thermal conductivity is required.

[0008] The present disclosure aims to provide a novel method for producing boron nitride particles that can produce boron nitride particles having low dielectric properties and high thermal conductivity, a method for producing a resin composition that includes this method, and applications of the method.

[0009] Specific means for achieving the above object are as follows. <1> A method for producing boron nitride particles, comprising a step of nitriding boron-containing particles containing boron atoms in a nitrogen gas atmosphere. <2> A method for producing boron nitride particles according to <1>, in which the boron-containing particles are nitrided under conditions of 1 to 20 atmospheres. <3> A method for producing boron nitride particles according to <1> or <2>, in which the boron-containing particles are nitrided under heating conditions of 1500°C to 2200°C. <4> A method for producing boron nitride particles according to any one of <1> to <3>, in which the boron-containing particles contain at least one selected from the group consisting of boron particles and boron carbide. <5> A method for producing boron nitride particles according to any one of <1> to <4>, in which the produced boron nitride particles have a core portion containing boron nitride and a shell portion covering at least a portion of the core portion and containing boron nitride, wherein the core portion and the shell portion are anisotropic. <6> The method for producing boron nitride particles according to <5>, wherein the core portion contains boron nitride arranged in a direction intersecting the periphery of the particle, and the shell portion contains boron nitride arranged along the periphery of the particle. <7> The method for producing boron nitride particles according to any one of <1> to <6>, wherein the aspect ratio of the boron-containing particles is 1 to 5. <8> The method for producing boron nitride particles according to any one of <5> to <7>, wherein the average particle size of the produced boron nitride particles is 50 nm to 10 μm. <9> The method for producing boron nitride particles according to any one of <5> to <8>, wherein the thickness of the shell portion of the produced boron nitride particles is 1 nm to 50 nm. <10> The method for producing boron nitride particles according to any one of <1> to <9>, wherein the aspect ratio of the produced boron nitride particles is 1 to 5. <11> The method for producing boron nitride particles according to any one of <1> to <10>, wherein in the step of nitriding the boron-containing particles, no components other than the boron-containing particles are used, or the amount of components other than the boron-containing particles used is 5 mass% or less relative to the boron-containing particles. <12> A method for producing a resin composition, comprising: a step of producing boron nitride particles by the method for producing boron nitride particles according to any one of <1> to <11>, and a step of mixing the produced inorganic filler containing the boron nitride particles with a curable resin.<13> A method for producing a resin composition according to <12>, wherein an inorganic filler other than boron nitride particles is further mixed in the mixing step. <14> A method for producing a semiconductor device, comprising the steps of: placing an element on a support member; and encapsulating the element with a resin composition produced by the method for producing a resin composition according to <12> or <13>. <15> A method for producing a copper-clad laminate, comprising the steps of: impregnating a substrate with the resin composition produced by the method for producing a resin composition according to <12> or <13> to form a prepreg sheet; and heating the prepreg in a state where copper foil is laminated to at least one surface of the prepreg. <16> A method for producing a heat dissipation sheet, comprising the step of producing a heat dissipation sheet having a resin composition layer using the resin composition produced by the method for producing a resin composition according to <12> or <13>. <17> A method for producing a heat dissipation sheet by the method for producing a heat dissipation sheet according to <16>, and the steps of: placing the heat dissipation sheet between a heat generating element and a heat dissipation element, and pressure-bonding the heat dissipation sheet to the heat generating element and the heat dissipation element.

[0010] According to the present disclosure, it is possible to provide a novel method for producing boron nitride particles that can produce boron nitride particles having low dielectric properties and high thermal conductivity, a method for producing a resin composition that includes this method, and applications of the same.

[0011] 1A and 1B are transmission electron microscope images of boron nitride particles of Example 1 and Example 2, respectively.

[0012] The present disclosure will be described in detail below. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure.

[0013] In the present disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes as long as the purpose of the process is achieved. In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in numerical ranges described in the present disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple corresponding substances. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, particles corresponding to each component may contain multiple types of particles. When multiple types of particles corresponding to each component are present in a composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0014] <Method for Producing Boron Nitride Particles> The method for producing boron nitride particles according to the present disclosure includes a step of nitriding boron-containing particles containing boron atoms in a nitrogen gas atmosphere.

[0015] When producing the boron nitride particles, the boron-containing particles may be heated, pressed, etc. in a nitrogen gas atmosphere, if necessary.

[0016] In the nitriding step, the boron-containing particles may be nitrided under a pressure of 1 to 20 atmospheres, or under a pressure of 1 to 15 atmospheres, or under a pressure of 5 to 15 atmospheres. By changing the pressure when nitriding the boron-containing particles, the thickness of the shell portion formed on the boron nitride particles can be adjusted.

[0017] In the nitriding step, the boron-containing particles are preferably heated in a nitrogen gas atmosphere at a temperature of preferably 1500°C to 2200°C, more preferably 1600°C to 2000°C, and even more preferably 1700°C to 1900°C.

[0018] The nitriding time when the boron-containing particles are nitrided in a nitrogen gas atmosphere is not particularly limited, and may be 1 hour to 20 hours, or may be 2 hours to 10 hours.

[0019] The boron-containing particles are not particularly limited as long as they are particles containing boron atoms, and examples thereof include boron particles and boron carbide.

[0020] The average particle size of the boron-containing particles may be 50 nm to 10 μm, 100 nm to 5 μm, 500 nm to 3 μm, or 1 μm to 3 μm. The average particle size of the boron-containing particles may be a volume average particle size, and can be measured as a volume average particle size (D50) using, for example, a laser diffraction scattering particle size distribution measuring device.

[0021] The aspect ratio of the boron-containing particles may be 1 to 5, or may be 1 to 3. The aspect ratio of the boron-containing particles can be determined, for example, using a scanning electron microscope, by measuring A / B of 100 randomly selected boron-containing particles, where A is the length in the major axis direction and B is the length in the minor axis direction, and then averaging the measured A / B values.

[0022] The specific surface area of ​​the boron-containing particles is 0.3 m 2 / g to 100m 2 / g, and 0.6m 2 / g to 50m 2 / g, and 2m 2 / g to 50m 2 / g, and 10m 2 / g to 30m 2 The specific surface area of ​​the boron-containing particles can be measured by the BET method (nitrogen gas adsorption method).

[0023] In the step of nitriding the boron-containing particles, components other than the boron-containing particles (other components) may be used. Alternatively, the above-mentioned other components may be contained inside or on the surface of the boron-containing particles. Examples of other components include metals such as Fe, Ni, Mg, Cr, Al, Na, Ca, Li, Y, and Ce, and compounds containing these metals (e.g., oxides). In the step of nitriding the boron-containing particles, components other than the boron-containing particles may not be used, and when components other than the boron-containing particles are used, the amount may be 5% by mass or less, 3% by mass or less, or 1% by mass or less relative to the boron-containing particles.

[0024] The nitrogen gas atmosphere is preferably an inert gas containing nitrogen gas as a main component, but the inert gas may contain components other than nitrogen gas (for example, oxygen gas) as long as the effects of the invention are achieved.

[0025] In the nitriding step, it is preferable to supply the boron-containing particles to a reactor such as an electric furnace or a heating furnace, and heat and pressurize the reactor in which the boron-containing particles are placed while filling the reactor with an inert gas containing nitrogen gas.

[0026] The boron nitride particles produced by the production method of the present disclosure comprise a core portion containing boron nitride and a shell portion covering at least a portion of the core portion and containing boron nitride, and the core portion and the shell portion may be anisotropic. The anisotropy of the boron nitride constituting the core portion and the shell portion allows the production of boron nitride particles having multiple properties, such as high thermal conductivity and high fluidity or high strength.

[0027] In the boron nitride particles produced by the production method of the present disclosure, the core preferably contains boron nitride arranged in a direction intersecting the periphery of the particle, and the shell preferably contains boron nitride arranged along the periphery of the particle. This gives the boron nitride constituting the core and shell anisotropy. More specifically, the boron nitride arranged in the core along a direction intersecting the periphery of the particle tends to have high isotropic thermal conductivity. Furthermore, the boron nitride arranged in the shell along the periphery of the particle allows the particle to have a low specific surface area, which tends to result in excellent fluidity of the composition when mixed with a resin component such as a curable resin.

[0028] The boron nitride particles produced by the manufacturing method of the present disclosure are not secondary particles formed by agglomeration of scaly boron nitride particles, and are therefore applicable to miniaturization and narrowing of semiconductor devices. The boron nitride particles produced by the manufacturing method of the present disclosure are preferably primary particles comprising at least a core portion and a shell portion, rather than secondary particles formed by agglomeration of boron nitride particles.

[0029] Boron nitride particles are applicable in fields requiring low dielectric properties and high thermal conductivity, and are also applicable in applications such as sealing materials that require fluidity, miniaturization, narrow gaps, etc. Boron nitride particles can be used in sealing materials, interlayer insulating materials, copper-clad laminates, heat dissipation sheets, molded products, etc.

[0030] The shape of the boron nitride particles is preferably spherical or polyhedral from the viewpoint of flowability, filling properties, etc. when used in a resin composition.

[0031] The boron nitride particles are preferably spherical in shape. The spherical boron nitride particles may be, for example, particles having an aspect ratio of 1 to 5, as described below.

[0032] The core portion contains boron nitride arranged in a direction intersecting the periphery of the boron nitride particle. The core portion may have layered boron nitride arranged radially or randomly. The boron nitride in the core portion may be continuous layered boron nitride in the radial direction (diagonal direction in the case of a polyhedron shape), or multiple layered boron nitride may be discontinuously arranged.

[0033] The shell preferably covers at least a portion of the core and contains boron nitride arranged along the periphery of the particle. The shell may be a layer in which multiple layers of boron nitride are arranged along the periphery of the particle. Multiple layers of boron nitride may be discontinuously arranged along the periphery of the particle.

[0034] The average particle size of the boron nitride particles may be 50 nm to 10 μm, 100 nm to 8 μm, 1 μm to 6 μm, or 2 μm to 6 μm. The average particle size of the boron nitride particles may be a volume average particle size, and can be measured as a volume average particle size (D50) using, for example, a laser diffraction scattering particle size distribution analyzer.

[0035] The aspect ratio of the boron nitride particles may be 1 to 5, or may be 1 to 3. The aspect ratio of the boron nitride particles can be determined, for example, using a scanning electron microscope, by measuring A / B, where A is the length in the major axis direction and B is the length in the minor axis direction, and then averaging the measured A / B values.

[0036] The specific surface area of ​​boron nitride particles is 0.3 m 2 / g to 100m 2 / g, and 0.6m 2 / g to 50m 2 / g, and 2m 2 / g to 50m 2 / g, and 12m 2 / g to 30m 2 The specific surface area of ​​the boron nitride particles can be measured by the BET method (nitrogen gas adsorption method).

[0037] The ratio of the specific surface area of ​​the boron nitride particles to the specific surface area of ​​the boron-containing particles, i.e., specific surface area of ​​boron nitride particles / specific surface area of ​​boron-containing particles, may be 0.5 to 2, 0.7 to 1.5, or 0.8 to 1.2.

[0038] The thickness of the shell portion may be 1 nm to 50 nm, 3 nm to 40 nm, or 5 nm to 30 nm. The thickness of the shell portion can be adjusted, for example, by changing the pressure conditions when nitriding the boron-containing particles. From the viewpoint of the strength of the boron nitride particles, the thickness of the shell portion is preferably 1 nm or more. From the viewpoint of increasing the thermal conductivity of the boron nitride particles, the thickness of the shell portion is preferably 50 nm or less. The thickness of the shell portion can be determined, for example, using a transmission electron microscope, and is the arithmetic average of measurements obtained at five arbitrarily selected locations.

[0039] The ratio of the length of the core portion to the thickness of the shell portion, i.e., core length / shell thickness, may be 1 to 10,000, 10 to 1,000, or 50 to 1,000. The core length / shell thickness of the boron nitride particles can be determined, for example, using a transmission electron microscope. The core length refers to the length of the major axis of the core portion.

[0040] <Method for producing resin composition> The method for producing a resin composition of the present disclosure includes the steps of producing boron nitride particles by the method for producing boron nitride particles of the present disclosure described above, and mixing the produced inorganic filler containing the boron nitride particles with a curable resin. The resin composition may be used to produce an encapsulating material, an interlayer insulating material, a copper-clad laminate, a heat dissipation sheet, a molded article containing boron nitride particles, or the like. In particular, the resin composition is suitable for applications requiring high thermal conductivity, low dielectric properties, and the like.

[0041] The curable resin is not particularly limited as long as it is a resin that is cured by heat, active energy rays such as ultraviolet rays, or the like, and examples thereof include epoxy resins, phenolic resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, urethane resins, vinyl resins, polyimide resins such as maleimide resins, polyamide resins, polyamideimide resins, silicone resins, (meth)acrylic resins, etc. The resin composition may contain only one type of curable resin, or may contain two or more types.

[0042] The resin composition of the present disclosure may contain components other than the boron nitride particles of the present disclosure (boron nitride particles produced by the method for producing boron nitride particles of the present disclosure; the same applies hereinafter) and the curable resin (also referred to as other components). Examples of other components include inorganic fillers other than the boron nitride particles, thermoplastic resins, initiators, coupling agents, ion exchangers, release agents, flame retardants, colorants, stress relaxation agents, curing accelerators, curing agents, polymerization inhibitors, solvents, etc.

[0043] The resin composition of the present disclosure may further contain an inorganic filler other than boron nitride particles (also referred to as "other inorganic fillers"). Examples of other inorganic fillers include silica, alumina, magnesium oxide, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, mica, aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as magnesium-zinc composite hydroxide, and zinc borate. The resin composition may contain only one type of other inorganic filler, or two or more types.

[0044] The resin composition of the present disclosure may or may not contain boron nitride particles other than the boron nitride particles of the present disclosure (also referred to as "other boron nitride particles"). Examples of other boron nitride particles include boron nitride particles obtained by methods other than the method for producing boron nitride particles of the present disclosure. The aspect ratio of the other boron nitride particles may be greater than 5.

[0045] The content of the boron nitride particles of the present disclosure may be 50% by mass or more, 70% by mass or more, or 90% by mass or more, based on the total mass of the boron nitride particles. The upper limit of the content of the boron nitride particles of the present disclosure may be 100% by mass or less, or may be 95% by mass or less, based on the total mass of the boron nitride particles.

[0046] When the resin composition of the present disclosure contains other inorganic fillers, the mixing ratio of the boron nitride particles of the present disclosure to the other inorganic fillers is not particularly limited and may be adjusted appropriately depending on the application, required physical properties, etc. For example, the content of the boron nitride particles of the present disclosure may be 10% by mass to 90% by mass, 20% by mass to 80% by mass, or 30% by mass to 70% by mass relative to the total of the boron nitride particles of the present disclosure and the other inorganic fillers.

[0047] The content of the boron nitride particles in the resin composition of the present disclosure may be 5% by volume to 95% by volume, 10% by volume to 90% by volume, 10% by volume to 50% by volume, or 50% by volume to 90% by volume.

[0048] The resin composition may be used for manufacturing a semiconductor device. For example, the semiconductor device may include a support member, an element disposed on the support member, and a cured product of the resin composition of the present disclosure encapsulating the element.

[0049] The above-mentioned semiconductor device can be manufactured, for example, by a method for manufacturing a semiconductor device including a step of placing an element on a support member and a step of encapsulating the element with a resin composition manufactured by the method for manufacturing a resin composition of the present disclosure.

[0050] (Copper-clad laminate) A laminate may be produced by laminating a prepreg, which is a sheet obtained by impregnating a substrate such as paper or glass with a resin using the resin composition, or a copper-clad laminate may be produced by providing copper foil on both sides of the laminate. For example, the copper-clad laminate may include a prepreg, which is a sheet obtained by impregnating a substrate with the resin composition, and copper foil arranged on at least one side of the prepreg, preferably on both sides of the prepreg.

[0051] The copper-clad laminate can be produced by a method for producing a copper-clad laminate, which includes the steps of: impregnating a substrate with a resin composition produced by the method for producing a resin composition of the present disclosure to produce a prepreg sheet; and heating the prepreg in a state in which copper foil is attached to at least one surface of the prepreg.

[0052] (Heat Dissipation Sheet) A heat dissipation sheet may be produced using the resin composition. The heat dissipation sheet has a resin composition layer containing the resin composition. The heat dissipation sheet may be a laminate in which a resin composition layer is disposed on a support. Alternatively, the heat dissipation sheet may be a heat dissipation device in which a heat generating element, a heat dissipation element, and a resin composition layer containing the resin composition are disposed between the heat generating element and the heat dissipation element.

[0053] The above-mentioned heat dissipation sheet can be manufactured by a method for manufacturing a heat dissipation sheet, which includes a step of manufacturing a heat dissipation sheet having a resin composition layer using a resin composition manufactured by the method for manufacturing a resin composition of the present disclosure.

[0054] The above-mentioned heat dissipation device can be manufactured by a method for manufacturing a heat dissipation device, which includes the steps of manufacturing a heat dissipation sheet using the heat dissipation sheet manufacturing method disclosed herein, and placing the heat dissipation sheet between a heating element and a heat dissipation element and pressing the heat dissipation sheet against the heating element and the heat dissipation element.

[0055] [Example 1] Boron particles (average particle diameter 1.4 μm, BET specific surface area 13.4 m) were used as a raw material for boron nitride particles. 2 The boron nitride particles were reacted for 4 hours under conditions of 1 atmosphere and 1750°C in a nitrogen gas atmosphere. This resulted in boron nitride particles having a core portion containing boron nitride arranged along a direction intersecting the periphery of the particle, and a shell portion covering at least a portion of the core portion and also containing boron nitride arranged along the periphery of the particle.

[0056] Example 2 Boron nitride particles were produced in the same manner as in Example 1, except that the pressure when reacting the boron particles was changed to 10 atmospheres.

[0057] [Comparative Example 1] (Scaly boron nitride particles) 40 g of boric acid, 20 g of melamine, and 10 g of water were mixed and stirred, and the mixture was placed in a mold and pressurized to a density of 0.7 g / cm 3 A molded body of the formula (1) was obtained. This molded body was dried in a dryer at 300°C for 8 hours, and then calcined at 1100°C under an ammonia gas atmosphere at 1 atmosphere pressure for 4 hours. The calcined product was then pulverized to obtain crude boron nitride powder. The crude boron nitride powder was then calcined at 1750°C under a nitrogen gas atmosphere at 1 atmosphere pressure for a total of 4 hours, and the calcined product was then washed with warm water at 60°C to obtain scaly boron nitride particles.

[0058] The boron nitride particles obtained in Examples 1 and 2 are shown in Figures 1 and 2 and Table 1. The aspect ratios in the tables represent the range from the minimum to the maximum value when the aspect ratios of multiple boron-containing particles were measured using a scanning electron microscope. The average particle size in the tables is the volume average particle size (D50) measured using a laser diffraction scattering particle size distribution analyzer. The particle size ranges in the tables represent the minimum and maximum particle sizes observed using a transmission electron microscope. As shown in Figures 1 and 2, the obtained boron nitride particles had a core portion containing boron nitride arranged in a direction intersecting the periphery of the particle and a shell portion containing boron nitride arranged along the periphery of the particle. The thickness of the shell portion could be adjusted by changing the pressure during nitriding of the boron particles.

[0059]

[0060] The disclosure of Japanese Patent Application No. 2023-213371, filed on December 18, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for producing boron nitride particles, comprising a step of nitriding boron-containing particles containing boron atoms in a nitrogen gas atmosphere.

2. The method for producing boron nitride particles according to claim 1, wherein the boron-containing particles are nitrided under a pressure of 1 to 20 atmospheres.

3. A method for producing boron nitride particles according to claim 1, wherein the boron-containing particles are nitrided under heating conditions of 1500°C to 2200°C.

4. The method for producing boron nitride particles according to claim 1, wherein the boron-containing particles include at least one selected from the group consisting of boron particles and boron carbide particles.

5. A method for producing boron nitride particles as described in claim 1, wherein the produced boron nitride particles have a core portion containing boron nitride and a shell portion covering at least a portion of the core portion and containing boron nitride, and the core portion and the shell portion are anisotropic.

6. A method for producing boron nitride particles as described in claim 5, wherein the core portion contains boron nitride arranged in a direction intersecting the outer periphery of the particle, and the shell portion contains boron nitride arranged along the outer periphery of the particle.

7. The method for producing boron nitride particles according to claim 1, wherein the aspect ratio of the boron-containing particles is 1 to 5.

8. A method for producing boron nitride particles according to claim 5, wherein the average particle size of the produced boron nitride particles is 50 nm to 10 μm.

9. A method for producing boron nitride particles according to claim 5, wherein the shell portion of the produced boron nitride particles has a thickness of 1 nm to 50 nm.

10. A method for producing boron nitride particles according to claim 7, wherein the aspect ratio of the produced boron nitride particles is 1 to 5.

11. A method for producing boron nitride particles as described in claim 1, wherein in the process of nitriding the boron-containing particles, no components other than the boron-containing particles are used, or the amount of components other than the boron-containing particles used is 5 mass% or less relative to the boron-containing particles.

12. A method for producing a resin composition, comprising: producing boron nitride particles by the method for producing boron nitride particles according to any one of claims 1 to 11; and mixing an inorganic filler containing the produced boron nitride particles with a curable resin.

13. The method for producing a resin composition according to claim 12, wherein in the mixing step, an inorganic filler other than boron nitride particles is further mixed.

14. A method for manufacturing a semiconductor device, comprising: a step of placing an element on a support member; and a step of encapsulating the element with a resin composition manufactured by the method for manufacturing a resin composition according to claim 12.

15. A method for producing a copper-clad laminate, comprising the steps of: impregnating a substrate with the resin composition produced by the method for producing a resin composition according to claim 12 to produce a prepreg sheet; and heating the prepreg in a state in which copper foil is laminated to at least one surface of the prepreg.

16. A method for producing a heat dissipation sheet, comprising the step of producing a heat dissipation sheet having a resin composition layer using a resin composition produced by the method for producing a resin composition according to claim 12.

17. A method for manufacturing a heat dissipation device, comprising: a step of manufacturing a heat dissipation sheet by the method for manufacturing a heat dissipation sheet according to claim 16; and a step of placing the heat dissipation sheet between a heating body and a heat dissipation body and pressing the heat dissipation sheet against the heating body and the heat dissipation body.