JP7794844B2 - Heat dissipation member and electronic device - Google Patents

Description

The present invention relates to a heat dissipation member and an electronic device.

A variety of heat dissipation components using copper-diamond composites have been developed to date. One example of this type of technology is described in Patent Document 1. Patent Document 1 states that, with regard to a metal matrix-thermal conductor particle composite material, because such composite materials contain ceramic particles such as diamond particles or SiC particles, it is difficult to polish the surface of the composite material to make it flat (paragraph 0012).

International Publication No. 2016/035796

However, after investigations by the inventors, it was found that there is room for improvement in the thermal conductivity of the heat dissipation member described in Patent Document 1 above.

Further research by the inventors led to the discovery that the thermal conductivity of the heat dissipation component can be improved by forming recesses (so-called shedding marks) at the joint surface between the copper-diamond composite and the metal film, which are formed by diamond particles shedding, and this led to the completion of the present invention.

According to one aspect of the present invention, the following heat dissipation member and electronic device are provided.

1. A copper-diamond composite having a plurality of diamond particles dispersed in a copper-containing metal matrix;
a metal film bonded to at least one surface of the copper-diamond composite;
A heat dissipation member comprising:
At least one cross section of the heat dissipation member in the lamination direction has at least one recess formed by shedding of the diamond particles on the bonding surface between the copper-diamond composite and the metal film.
Heat dissipation material.
2. The heat dissipation member according to 1.,
A heat dissipation member having a structure in which the metal film is embedded inside at least one of the recesses.
3. The heat dissipation member according to 1. or 2.,
A heat dissipation member, wherein the diamond particles shed from the bonding surface have a shedding rate of 0.5% or more and 10% or less in terms of number.
4. The heat dissipation member according to any one of 1. to 3.,
A heat dissipation member in which the thermal conductivity of the copper-diamond composite is 600 W/m·K or more.
5. The heat dissipation member according to any one of 1. to 4.,
A heat dissipation component in which, when the particle size distribution of the diamond particles is measured using an image particle size distribution measuring device, _{the S50} , which is the sphericity at which the cumulative value reaches 50% in the volume particle size distribution of the sphericity of the diamond particles, is 0.75 or more.
6. The heat dissipation member according to any one of 1. to 5.,
A heat dissipation component, wherein when the particle size distribution of the diamond particles is measured using an image particle size distribution measuring device, the particle size _D50 , which is the particle size at which the cumulative value reaches 50% in the volume particle size distribution of the particle diameters of the diamond particles, is 300 μm or less.
7. The heat dissipation member according to any one of 1. to 6.,
The heat dissipation member, wherein the metal matrix is composed of a sintered body of metal powder.
8. The heat dissipation member according to any one of 1. to 7.,
an electronic component provided on the heat dissipation member.

The present invention provides a heat dissipation component with excellent thermal conductivity and an electronic device using the same.

FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a heat dissipation member according to the present embodiment.

Embodiments of the present invention will be described below using the drawings. Note that in all drawings, similar components will be given similar symbols and descriptions will be omitted where appropriate. Also, the drawings are schematic and do not correspond to actual dimensional proportions.

The heat dissipation member of this embodiment will be outlined with reference to FIG.
FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a heat dissipation member according to this embodiment.

The heat dissipation member 100 of this embodiment includes a copper-diamond composite 30 in which a plurality of diamond particles 20 are dispersed in a copper-containing metal matrix 10, and a metal film 50 bonded to at least one surface of the copper-diamond composite 30, and has at least one recess 70 formed by shedding of diamond particles on the bonding surface (bonding interface 12) between the copper-diamond composite 30 and the metal film 50 in at least one cross section in the stacking direction.

In the heat dissipation member 100 of this embodiment, the surface (bonding interface 12) of the copper-diamond composite 30 (hereinafter sometimes simply referred to as the "composite") has one or more recesses 70 formed by removing all or part of the diamond particles. A metal film 50 is embedded at least partially or entirely inside the recesses 70 on the surface of the composite. By having at least one or more recesses 70 have such an embedded structure, it becomes possible to effectively express the heat conduction properties inherent to diamond from the composite to the metal film 50. This makes it possible to improve the thermal conductivity of the heat dissipation member 100.
Furthermore, the above-described embedded structure improves the adhesion between the composite and the metal film 50, thereby enabling the thickness of the metal film 50 to be reduced, thereby further improving the thermal conductivity of the heat dissipation member 100.

The lower limit of the shedding rate of diamond particles shed from the bonding surface, calculated in number, is preferably 0.5% or more, more preferably 0.3% or more, and even more preferably 0.2% or more. This improves the thermal conductivity of the heat dissipation member. It also improves the adhesion between the composite and the metal film, thereby improving the durability of the heat dissipation member.
On the other hand, the upper limit of the shedding rate of the diamond particles, calculated as the number of particles, is preferably 10% or less, more preferably 8% or less, and even more preferably 5% or less. Excessive shedding is not preferable because, when a surface copper layer is formed and smoothed, a large amount of copper remains in the shedding traces, reducing thermal conductivity.

The diamond particle shedding rate is calculated based on the formula: B/A x 100 (%), where A is the total number of diamond particles (including recesses formed by shedding of diamond particles) exposed on the surface of the composite, and B is the recesses formed by shedding of diamond particles.
The number of recesses formed by particle shedding is calculated based on a cross-sectional SEM image. The cross-sectional SEM image may be of either the composite or the heat dissipation member, but a cross-sectional SEM image of the composite is preferred.

Furthermore, according to further findings of the present inventors, it has been found that the degree of smoothness on the surface of the copper-diamond composite and the shedding rate of diamond particles can be appropriately controlled by, for example, appropriately adjusting the particle size and sphericity of the diamond particles, the grain size (grit) of the grinding stone used for grinding and polishing, and using grinding means with gentle conditions.
Although the detailed mechanism is unclear, it is believed that by using a grinding method under mild conditions to prevent cracking and falling off of diamond particles while moderately smoothing the surface of the copper-diamond composite, it is possible to reduce the thickness of the metal film formed on the surface of such a composite, and as a result, it is possible to improve the thermal conductivity of the entire heat dissipation component composed of the copper-diamond composite and the metal film.
On the other hand, if the surface of the copper-diamond composite is not smoothed, no diamond particles are removed, but a thick metal film must be formed to fill in the large irregularities on the surface. However, if the metal film on the surface of the composite is made too thick, there is a risk that the overall thermal conductivity will decrease.

The lower limit of the thermal conductivity of the heat dissipation member 100 is preferably 600 W/m·K or more, more preferably 630 W/m·K or more, and even more preferably 650 W/m·K or more. This improves the heat dissipation characteristics of the heat dissipation member.
On the other hand, the upper limit of the thermal conductivity of the heat dissipation member 100 is not particularly limited, but is preferably 950 W/m·K or less, more preferably 900 W/m·K or less, and even more preferably 870 W/m·K or less.

The configuration of the heat dissipation member of this embodiment will be described in detail.

The heat dissipation member 100 comprises a copper-diamond composite 30 and a metal film 50.

(Copper-diamond composite)
The copper-diamond composite 30 includes a copper-containing metal matrix 10 and a plurality of diamond particles 20 present in the metal matrix 10 .

The lower limit of the thermal conductivity of the copper-diamond composite 30 is preferably 600 W/m·K or more, more preferably 630 W/m·K or more, and even more preferably 650 W/m·K or more, thereby improving the heat dissipation characteristics of the heat dissipation member.
On the other hand, the upper limit of the thermal conductivity of the copper-diamond composite 30 is not particularly limited, but is preferably 950 W/m·K or less, more preferably 900 W/m·K or less, and even more preferably 870 W/m·K or less.

The shape and size of the copper-diamond composite 30 can be appropriately set depending on the application.
The copper-diamond composite 30 may have, for example, a flat plate, a block, a rod, or the like shape.

The metal matrix 10 may contain copper, or may contain a high thermal conductivity metal other than copper. That is, the metal matrix 10 is composed of a copper phase and/or a copper alloy phase.

The main component of the metal matrix 10 is preferably copper from the viewpoints of thermal conductivity and cost.
The lower limit of the content of copper as the main component is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more, based on 100% by mass of the metal matrix 10. This allows the excellent thermal conductivity of copper and copper alloys to be utilized. Furthermore, the same copper as the matrix can be used as the surface layer to ensure brazability and surface smoothness, eliminating the need to form another surface coating layer.
The upper limit of the content of copper as the main component is not particularly limited, but may be 100% by mass or less, or 99% by mass or less, based on 100% by mass of the metal matrix 10 .

Examples of other highly thermally conductive metals include silver, gold, and aluminum. These may be used alone or in combination of two or more. When copper is combined with other highly thermally conductive metals, an alloy or composite material formed of copper and the other highly thermally conductive metal may be used.
The metal matrix 10 may be made of metals other than high thermal conductivity metals as long as the effects of the present invention are not impaired.

Furthermore, when a copper alloy is used as the metal matrix 10, examples of the copper alloy include CuAg, CuAl, CuSn, CuZr, CrCu, etc.

The metal matrix 10 is, for example, a sintered body of metal powder containing copper (and other photothermal conductive metals as needed). In this embodiment, the metal matrix 10 is composed of a sintered body having at least some of the diamond particles 20 embedded therein.

The diamond particles 20 may be configured so that the entirety of the multiple particles is embedded in the metal matrix 10, but at least a portion of one particle or multiple particles is exposed at the bonding interface 12 of the copper-diamond composite 30.

Diamond particles 20 include at least one of uncoated diamond particles that do not have a metal-containing coating layer on their surface, and coated diamond particles that have a metal-containing coating layer on their surface. Coated diamond particles are more preferred from the standpoint of improving adhesion between the diamond and metal particles and dispersibility.

The lower limit of the volume ratio of diamond particles 20 in the copper-diamond composite 30 is preferably 10% by volume or more, more preferably 20% by volume or more, and even more preferably 30% by volume or more, thereby increasing the thermal conductivity of the copper-diamond composite 30.
On the other hand, the upper limit of the volume ratio of diamond particles 20 in the copper-diamond composite 30 is, for example, preferably 80 volume % or less, more preferably 70 volume % or less, and even more preferably 60 volume % or less. This makes it possible to prevent large pores from remaining around the diamond particles 20 in the copper-diamond composite 30 due to a decrease in the adhesion of copper powder around the diamond particles 20, and realizes a structure with excellent manufacturing stability.

When coated diamond particles are used as diamond particles 20, the metal-containing coating layer in the coated diamond particles may contain molybdenum, tungsten, chromium, zirconium, hafnium, vanadium, niobium, tantalum, and alloys thereof. These may be used alone or in combination of two or more. The metal-containing coating layer is configured to cover at least a portion or the entire surface of the particle.

The sphericity and particle size of the diamond particles 20 are measured according to the following procedure.
The particle size distribution of the diamond particles 20 is measured using an image-based particle size distribution measuring device (for example, Morphologi4 manufactured by Malvern). The particle size distribution includes a shape distribution and a particle diameter distribution.
From the particle size distribution thus obtained, a volume particle size distribution of sphericity and a volume particle size distribution of particle diameter are created.
Then, in the volume particle size distribution of the sphericity of the diamond particles 20, a predetermined cumulative value of sphericity and a predetermined cumulative value of particle diameter are determined.
Here, the sphericity and particle size are defined as follows.
Sphericity: The ratio of the circumference of a circle with the same area as the projected object to the circumference of the object. Particle diameter: The maximum length at two points on the outline of the particle image.

The lower limit of the sphericity _S50 at which the cumulative value of the diamond particles 20 reaches 50%, as measured according to the above procedure, is, for example, 0.75 or more, preferably 0.80 or more, more preferably 0.85 or more, and even more preferably 0.9 or more. This increases the degree of packing of the diamond particles 20 and increases the thermal conductivity of the composite.
On the other hand, the upper limit of the sphericity _S50 is not particularly limited, but may be, for example, 1.0 or less, or 0.99 or less.

The upper limit of the particle diameter _D50 at which the cumulative value of the diamond particles 20 reaches 50%, as measured according to the above procedure, is, for example, 300 μm or less, preferably 270 μm or less, more preferably 250 μm or less, even more preferably 220 μm or less, particularly preferably 200 μm or less, and most preferably 180 μm or less. This increases the degree of packing of the diamond particles 20 and increases the thermal conductivity of the composite.
The lower limit of the particle diameter _D50 is not particularly limited, but may be, for example, 5 μm or more.

In the heat dissipation member 100, the plurality of diamond particles 20 may be configured to include a first diamond particle having at least a portion of its surface exposed from the metal matrix 10 and a second diamond particle having its entire surface embedded in the metal matrix 10.
The heat dissipation member 100 may also have a connecting structure in which one of the first diamond particles is in contact with one of the second diamond particles, and in the connecting structure, at least one, two, or four or more of the second diamond particles may be in continuous contact with each other.
This improves the thermal conductivity of the heat dissipation member 100 .
The above-described connection structure is confirmed in at least one cross section of the heat dissipation member 100 in the thickness direction.

The upper limit of the flatness of the copper-diamond composite 30 calculated in accordance with JIS B 0621: 1984 is, for example, 40 μm or less, preferably 39 μm or less, and more preferably 38 μm or less, which can improve the adhesion between the composite and the metal film and suppress a decrease in the thermal conductivity of the heat dissipation member.
On the other hand, the lower limit of the flatness is not particularly limited, but may be 1 μm or more.

The upper limit of the ten-point average height of the diamond particle surface exposed at the surface (bonding interface 12) of the copper-diamond composite 30, calculated in accordance with JIS B 0601:2013, is, for example, 5 μm or less, preferably 4 μm or less, and more preferably 3 μm or less, thereby improving the adhesion between the composite and the metal film.
On the other hand, the lower limit of the ten-point average height of the diamond particle surface is not particularly limited, but may be 0.1 μm or more.

(metal film)
The metal film 50 may be formed on at least one surface of the copper-diamond composite 30, and may be formed on both surfaces of the copper-diamond composite 30 in the form of a flat plate, for example.

The metal film 50 may contain one or more elements selected from the group consisting of copper, silver, gold, aluminum, nickel, zinc, tin, and magnesium. Preferably, the metal film 50 contains the same metal as the main component metal in the metal matrix 10, and preferably contains at least copper or a copper alloy.

The content of the main component copper is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more, out of 100% by mass of the metal film 50.
The upper limit of the content of copper as the main component is not particularly limited, but may be 100 mass % or less, or 99 mass % or less, based on 100 mass % of the metal film 50 .

The upper limit of the thickness of the metal film 50 is preferably 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less, which increases the thermal conductivity of the heat dissipation member.
On the other hand, the lower limit of the film thickness of the metal film 50 is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more, which can increase the adhesive strength with the composite and the durability of the metal film itself.

The metal film 50 is obtained by, for example, sputtering or plating.
The average crystal grain size of the metal in the metal film 50 is preferably 5 nm to 50 nm, more preferably 10 nm to 40 nm, and even more preferably 20 nm to 30 nm. The average crystal grain size is measured using a transmission electron microscope (TEM).

The electronic device of this embodiment comprises the above-mentioned heat dissipation member and electronic components mounted on the heat dissipation member.

Examples of electronic components include semiconductor elements. Specific examples of semiconductor elements include power semiconductors, image display elements, microprocessor units, and laser diodes.

Heat dissipation components are used in heat sinks and heat spreaders. Heat sinks dissipate heat generated by semiconductor elements during operation to the external space, while heat spreaders transfer heat generated by semiconductor elements to other components.

Electronic components may be mounted directly on the heat dissipation member or indirectly via a ceramic substrate or the like.

An example of a method for manufacturing the heat dissipation member of this embodiment is described below.

An example of a method for manufacturing a heat dissipation component includes a raw material mixing process, a sintering process, a smoothing process, and a film formation process.

In the raw material mixing step, a metal powder containing copper, such as copper powder, and diamond particles are mixed to obtain a mixture.
The raw material powders can be mixed by various methods, such as dry and wet methods, but a dry mixing method may also be used.

In the firing step, the mixture of metal powder and diamond particles is fired to obtain a composite sintered body of copper and diamond particles.
The firing temperature can be appropriately selected depending on the type of metal contained in the metal powder, but in the case of copper powder, it is preferably 800°C or higher and 1100°C or lower, more preferably 850°C or higher and 1000°C or lower. By setting the firing temperature to 800°C or higher, the copper-diamond composite is densified and the desired thermal conductivity is obtained. By setting the firing temperature to 1100°C or lower, deterioration due to graphitization of the interfaces between diamond particles can be suppressed, and a decrease in the inherent thermal conductivity of diamond can be prevented.
The firing time is not particularly limited, but is preferably 5 minutes to 3 hours, more preferably 10 minutes to 2 hours. By setting the firing time to 5 minutes or more, the copper-diamond composite is densified and the desired thermal conductivity is obtained. By setting the firing time to 3 hours or less, it is possible to prevent the formation of carbides and thickening of the film between the diamond in the coated diamond particles and the metal coating the surface, which can lead to a decrease in thermal conductivity due to phonon scattering and cracks due to differences in linear expansion coefficients. In addition, the productivity of the composite can be improved.

The firing process can be carried out using either atmospheric sintering or pressure sintering, but pressure sintering is preferred in order to obtain a dense composite.

Examples of pressure sintering methods include hot press sintering, spark plasma sintering (SPS), and hot isostatic pressing (HIP). In the case of hot press sintering and SPS sintering, the pressure is preferably 10 MPa or more, more preferably 30 MPa or more. On the other hand, in the case of hot press sintering and SPS sintering, the pressure is preferably 100 MPa or less. By setting the pressure to 10 MPa or more, the copper-diamond composite becomes densified and the desired thermal conductivity is obtained. Setting the pressure to 100 MPa or less prevents cracking of the diamond, an increase in the diamond interface, and a decrease in adhesion between the crushed diamond surface and the metal, which would result in a decrease in the diamond's inherent thermal conductivity.

In the smoothing process, at least a portion of the surface of the composite sintered body is ground and polished to obtain a copper-diamond composite.

In the film formation process, a metal film is formed on at least a portion of the surface of the smoothed copper-diamond composite.

The metal film may be formed by a common method such as sputtering, plating, or pressure co-firing using copper foil, but sputtering may also be used to make the film thinner.
Furthermore, at least a part of the surface of the metal film may be subjected to surface grinding or polishing, which can improve the surface smoothness of the metal film after the film formation process.

An annealing step may be added between the firing step and the smoothing step.
Furthermore, prior to the film-forming step, the copper-diamond composite may be subjected to a process such as shaping or drilling.

The above describes embodiments of the present invention, but these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. that are within the scope of achieving the objectives of the present invention are included in the present invention.

The present invention will now be described in detail with reference to examples, but the present invention is not limited to the descriptions of these examples in any way.

<Production of composite and heat dissipation member>
Example 1
Copper powder and diamond particles (Mo coated) were weighed out to a ratio of 50% by volume:50% by volume, and the weighed powders were mixed uniformly in a V-type mixer to obtain a mixture (raw material mixing step).
Next, the resulting mixture was filled into a mold using an SPS sintering device and heated and sintered at 900°C for 1 hour under a pressure of 30 MPa, obtaining a disk-shaped composite sintered body consisting of multiple diamond particles dispersed in a copper matrix (sintering process).

The particle size distribution (shape distribution/particle size distribution) of the diamond particles used as raw material was measured using an image particle size distribution measuring device (Morphologi 4, manufactured by Malvern).
The sphericity _S50 , the cumulative value of which reaches 50% in the volume particle size distribution of the sphericity of the diamond particles, and the particle diameter _D50 , the cumulative value of which reaches 50% in the volume particle size distribution of the particle diameter of the diamond particles, were determined. These values were taken as the average of values measured twice.
The sphericity and particle size were defined as follows:
Sphericity: Ratio of the circumference of a circle having the same area as the projected object to the circumference of the object. Particle diameter: Maximum length at two points on the contour of the particle image. As a result, the sphericity _S50 of the diamond particles used was 0.9 and the particle diameter _D50 was 200 μm.

Both sides of the obtained composite sintered body were smoothed by surface grinding and polishing using a #400 grinding wheel, resulting in a copper-diamond composite (ground composite sintered body) with an outer diameter of 30 mm and a thickness of 3 mm (smoothing process).

The content of diamond particles in the copper-diamond composite was 50.8% by volume.
The flatness of one of the smoothed surfaces of the copper-diamond composite (the surface region spanning from the copper matrix to the diamond particles) was observed and measured using a digital microscope (VHX-8000, manufactured by Keyence). The flatness calculated in accordance with JIS B 0621:1984 was 30.1 μm.
The ten-point average height of the diamond particle surfaces exposed on the surface of the copper-diamond composite (ten-point average height Rz of the diamond surface) was 1.5 μm.
The thermal conductivity of the copper-diamond composite was measured by a laser flash method and found to be 753 W/m·K. The laser flash method was performed at room temperature with a carbon coating applied to the sample surface.

Thereafter, a Cu film having a thickness of 30 μm was formed on each of both surfaces of the copper-diamond composite by sputtering, to obtain a heat dissipation member composed of Cu film/copper-diamond composite/Cu film (film forming step).
The thermal conductivity of the heat dissipation member was measured by a laser flash method and was found to be 748 W/m·K.
The average crystal grain size of the Cu film in the heat dissipation member was 26 nm. The crystal grain size was measured by calculating the number of crystal grains within 1 ^μm2 from the structure obtained by a transmission electron microscope.

A cross-sectional SEM image was taken of the heat dissipation member of Example 1 in the thickness direction (the stacking direction of the composite and the Cu film). In the taken cross-sectional SEM image, it was confirmed that the copper-diamond composite had multiple depressions (grain shedding marks) formed by the shedding of diamond particles at the interface (bonding surface) with the Cu film (metal film).
The diamond particle shedding rate is calculated based on the formula: B/A x 100 (%), where A is the total number of diamond particles (including recesses formed by shedding of diamond particles) exposed on the surface of the composite, and B is the recesses formed by shedding of diamond particles. The number of recesses formed by shedding was calculated based on a cross-sectional SEM image of the composite.

(Examples 2 to 6, Comparative Example 1)
A composite and a heat dissipation member were obtained in the same manner as in Example 1, except that the particle size and sphericity of the diamond particles in Table 1 were changed and the grinding and polishing conditions were changed to those described in the remarks.
The obtained composite and heat dissipation member were evaluated in the same manner as in Example 1.
In the heat dissipation members of Examples 2 to 6, the cross-sectional SEM images confirmed the presence of multiple depressions (grain shedding marks) formed by diamond grain shedding. On the other hand, in Comparative Example 1, no grain shedding marks were confirmed.

As shown in Table 1, the heat dissipation members of Examples 1 to 6 were shown to be able to achieve superior thermal conductivity compared to Comparison Example 1.

This application claims priority based on Japanese Patent Application No. 2021-177306, filed on October 29, 2021, the disclosure of which is incorporated herein in its entirety.

10 Metal matrix 12 Bonding interface 20 Diamond particles 30 Copper-diamond composite 50 Metal film 70 Recess 100 Heat dissipation member

Claims (7)

a copper-diamond composite having a plurality of diamond particles dispersed in a copper-containing metal matrix;
a metal film bonded to at least one surface of the copper-diamond composite;
A heat dissipation member comprising:
At least one cross section of the heat dissipation member in the lamination direction has at least one recess formed by shedding of the diamond particles on the bonding surface between the copper-diamond composite and the metal film,
A heat dissipation member, wherein the diamond particles shed from the bonding surface have a shedding rate of 0.5% or more and 10% or less in terms of number. The heat dissipation member according to claim 1,
A heat dissipation member having a structure in which the metal film is embedded inside at least one of the recesses. The heat dissipation member according to claim 1 or 2,
A heat dissipation member in which the thermal conductivity of the copper-diamond composite is 600 W/m·K or more. The heat dissipation member according to claim 1 or 2,
A heat dissipation component in which, when the particle size distribution of the diamond particles is measured using an image particle size distribution measuring device, _{the S50} , which is the sphericity at which the cumulative value reaches 50% in the volume particle size distribution of the sphericity of the diamond particles, is 0.75 or more. The heat dissipation member according to claim 1 or 2,
A heat dissipation component, wherein when the particle size distribution of the diamond particles is measured using an image particle size distribution measuring device, the particle size _D50 , which is the particle size at which the cumulative value reaches 50% in the volume particle size distribution of the particle diameters of the diamond particles, is 300 μm or less. The heat dissipation member according to claim 1 or 2,
The heat dissipation member, wherein the metal matrix is composed of a sintered body of metal powder. The heat dissipation member according to claim 1 or 2;
an electronic component provided on the heat dissipation member.