WO2019106874A1

WO2019106874A1 - Insulating substrate and heat dissipation device

Info

Publication number: WO2019106874A1
Application number: PCT/JP2018/026025
Authority: WO
Inventors: 南　和彦; 平野　智哉
Original assignee: 昭和電工株式会社
Priority date: 2017-11-28
Filing date: 2018-07-10
Publication date: 2019-06-06
Also published as: JP2019096841A; CN111386601A

Abstract

An insulating substrate (6) comprises: a wiring layer (1) having a mounting surface (1a) on which a heat-generating element (21) is mounted; and an insulating layer (4) that is disposed below the wiring layer (1) so as to be layered under the wiring layer (1). The mounting surface (1a) is the top surface of the wiring layer (1). The upper portion of the wiring layer (1) has an aluminum-carbon particle composite layer (2). The section of the wiring layer (1) below the composite layer (2) is a pure aluminum layer (3) having a purity of 99% or greater.

Description

Insulating substrate and heat dissipation device

The present invention relates to an insulating substrate and a heat dissipation device on which a heat generating element such as an electronic element is mounted.

Although the vertical direction of the insulating substrate and the heat dissipation device according to the present invention is not limited, in the present specification and claims, in order to facilitate understanding of the configurations of the insulating substrate and the heat dissipation device, a heat generating element The mounting surface side of the insulating substrate on which the is mounted is defined as the upper side of the insulating substrate and the heat dissipation device, and the opposite side is defined as the lower side of the insulating substrate and the heat dissipation device.

In the present specification and claims, aluminum having a purity of 99% or more is referred to as "pure aluminum". Thus, the term "pure aluminum" includes high purity aluminum (4N purity) and ultra high purity aluminum (5N purity or more), unless otherwise specified. The purity 4N means 99.99%, and the purity 5N or more means 99.999% or more.

For example, insulating substrates used in power devices are generally required to have high reliability against thermal stress in a thermal cycle test (eg, power cycle test).

This insulating substrate is provided with a wiring layer having a mounting surface on which a semiconductor chip is mounted as a heat generating element, for example. An insulating layer (ceramic layer) is generally bonded to the surface of the wiring layer opposite to the mounting surface.

This wiring layer is required to have high thermal conductivity (high thermal conductivity). Therefore, conventional wiring layers are generally formed of pure aluminum.

Patent 5150905 (patent document 1) discloses an aluminum-carbon particle composite as a material having high thermal conductivity. Therefore, in order to obtain a wiring layer having high thermal conductivity, JP-A-2017-7172 (Patent Document 2) discloses using this composite material as a material of the wiring layer.

Patent No. 5150905 JP, 2017-7172, A

In recent years, semiconductor chips operable at high temperature using silicon carbide (SiC) or the like have been developed. When such a semiconductor chip is mounted on the mounting surface of the wiring layer, the insulating substrate is required to have high thermal conductivity and reliability higher than the reliability against the thermal stress required for the conventional insulating substrate. .

The present invention has been made in view of the above-described technical background, and an object thereof is to provide an insulating substrate and a heat dissipation device having high thermal conductivity and high reliability against thermal stress.

Other objects and advantages of the present invention will be apparent from the following preferred embodiments.

The present invention provides the following means.

[1] A wiring layer having a mounting surface for a heat-generating element formed of an upper surface, and an insulating layer disposed below the wiring layer in a stacked manner with respect to the wiring layer,
The upper portion of the wiring layer has an aluminum-carbon particle composite layer,
An insulating substrate, wherein a portion of the wiring layer below the composite material layer has a pure aluminum layer with a purity of 99% or more.

[2] The insulating substrate as recited in the aforementioned Item 1, wherein the purity of aluminum of the pure aluminum layer is 99.99% or more.

[3] The insulating substrate as recited in the

aforementioned Item

1 or 2, wherein the thickness of the composite material layer is 100 μm or more.

[4] A heat dissipation device comprising the insulating substrate according to any one of the above 1 to 3 and a heat dissipation member.

The present invention has the following effects.

In the preceding paragraph 1, since the upper portion of the wiring layer has the aluminum-carbon particle composite material layer, the thermal conductivity of the wiring layer is high. Therefore, the insulating substrate has high thermal conductivity.

In addition, when the upper portion of the wiring layer has the above-described composite material layer, the linear expansion coefficient of the upper portion of the wiring layer approaches the linear expansion coefficient of the heat-generating element or the solder layer. As a result, the durability and reliability of the solder layer can be improved and stress on the heat-generating element can be relaxed. Furthermore, since the portion below the composite layer in the wiring layer has a pure aluminum layer with a purity of 99% or more, the thermal stress generated between the wiring layer and the insulating layer during the thermal cycle load is a pure aluminum layer. Be relieved. Therefore, the insulating substrate has high reliability against thermal stress.

Furthermore, when the upper portion of the wiring layer has the above-described composite material layer, it is possible to suppress the occurrence of wrinkles on the mounting surface due to the thermal stress between the pure aluminum layer of the wiring layer and the insulating layer.

In the preceding paragraph 2, when the purity of aluminum of the pure aluminum layer is 99.99% or more, the reliability against thermal stress can be further enhanced for the insulating substrate.

In the preceding paragraph 3, when the composite material layer is 100 μm or more, the occurrence of wrinkles on the mounting surface can be reliably suppressed.

In the preceding paragraph 4, it is possible to provide a heat dissipation device having the effect of any one of the preceding paragraphs 1 to 3.

FIG. 1 is a cross-sectional view of a heat dissipation device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a state in the middle of laminating a plurality of preform foils and a pure aluminum layer. FIG. 3 is a cross-sectional view of a state in the middle of sintering a laminate of a plurality of preform foils and a pure aluminum layer. FIG. 4 is a cross-sectional view of a state in which a wiring layer, an insulating layer, and a first buffer layer are joined and integrated by brazing. FIG. 5 is a cross-sectional view of the insulating substrate according to the first embodiment of the present invention, in which the wiring layer, the insulating layer, and the first buffer layer are integrally joined. FIG. 6 is a cross-sectional view of a heat dissipation device according to a second embodiment of the present invention.

Next, several embodiments of the present invention will be described below with reference to the drawings.

1 to 5 are diagrams for explaining the first embodiment of the present invention.

As shown in FIG. 1, the heat dissipation device 10A according to the first embodiment is used for heat dissipation of power devices (eg, IGBTs, MOSFETs) etc., and in the order from top to bottom, the wiring layer 1, the insulating layer 4, a first buffer layer 5, a second buffer layer 7A, and a heat dissipation member (including a cooling member) 8 are provided in a stacked manner. Then, the heat dissipation device 10A is formed by joining and integrating them in a layered manner by a predetermined joining means. The insulating substrate 6 according to the first embodiment of the present invention includes the wiring layer 1, the insulating layer 4, and the first buffer layer 5.

Wiring layer 1 has mounting surface 1a formed of the upper surface thereof. For example, a semiconductor chip (indicated by a two-dot chain line) 21 is joined on the mounting surface 1 a as a heat-generating element via a solder layer (indicated by a two-dot chain line).

The insulating layer 4 has electrical insulation and is usually made of a ceramic plate such as an aluminum nitride plate (AlN).

The first buffer layer 5 and the second buffer layer 7A relieve stress such as thermal stress generated in the insulating substrate 6 and the heat dissipation device 10A. The first buffer layer 5 is made of a metal plate, for example, a pure aluminum plate. The second buffer layer 7A is made of a metal plate, and more specifically, is made of an aluminum punching metal plate having a plurality of through holes 7Aa.

The heat dissipating member 8 is liquid-cooled and includes a case 8 a and a corrugated inner fin 8 b disposed in the case 8 a. Inside the case 8a, there are formed a plurality of flow paths 8c divided by the inner fins 8b, through which a cooling fluid (not shown) as a cooling fluid flows.

The heat dissipating member 8 is made of metal, and more specifically, made of aluminum. More specifically, the case 8a of the heat dissipating member 8 is made of an aluminum brazing sheet provided with a brazing material layer (not shown) on at least the inner surface of the outer and inner surfaces, and the inner fins 8b of the heat dissipating member 8 are made of an aluminum plate. Or an aluminum brazing sheet provided with a brazing material layer (not shown) on at least one side of both sides. The wave top and the wave bottom of the inner fin 8b are brazed to the inner surface of the case 8a.

In the heat dissipation device 10A, the heat generated in the semiconductor chip 21 is sequentially conducted to the wiring layer 1, the insulating layer 4, the first buffer layer 5, the second buffer layer 7A, and the heat dissipation member 8 to flow through the flow path 8c. Dissipated. As a result, the temperature of the semiconductor chip 21 decreases.

The configuration of the wiring layer 1 will be described in detail below.

The upper portion of the wiring layer 1 has an aluminum-carbon particle composite layer 2. A portion of the wiring layer 1 below the composite material layer 2 has a pure aluminum layer (indicated by dot hatching) 3 having a purity of 99% (unit: mass%) or more.

More specifically, the wiring layer 1 is composed of the composite material layer 2 and the pure aluminum layer 3. That is, the upper portion of the wiring layer 1 is made of the composite material layer 2, and the mounting surface 1 a is made of the upper surface of the composite material layer 2. The entire portion of the wiring layer 1 below the composite material layer 2 is made of a pure aluminum layer 3.

The composite material layer 2 and the pure aluminum layer 3 are joined by a predetermined joining means. More specifically, both

layers

2 and 3 are sintered joined, that is, both

layers

2 and 3 are joined (sintered together) by sintering. ). The code | symbol "X" in FIG. 1 is a joint surface (sintering joint surface if it explains in full detail) (it shows with a dashed-two dotted line) of the composite material layer 2 and the pure aluminum layer 3.

Further, the pure aluminum layer 3 of the wiring layer 1 and the insulating layer 4 disposed below the wiring layer 1 are brazed and joined in a laminated manner.

As described above, when the upper portion of the wiring layer 1 is made of the composite material layer 2, the thermal conductivity (thermal conductivity) of the wiring layer 1 can be increased. The coefficient of linear expansion of the solder layer 22 can be approached, whereby the durability and reliability of the solder layer 22 can be improved and stress on the semiconductor chip 21 can be relaxed.

A portion under the composite material layer 2 in the wiring layer 1 is made of the pure aluminum layer 3 so that when a thermal cycle load is applied to the heat dissipation device 10A (the insulating substrate 6) (example: thermal cycle test) The thermal stress generated between the layer 1 and the insulating layer 4 can be relaxed by the pure aluminum layer 3.

Although the thickness of the wiring layer 1 is not limited, the lower limit of the thickness of the wiring layer 1 is preferably 200 μm, and the upper limit of the thickness of the wiring layer 1 is preferably 3 mm, and particularly the wiring layer The upper limit of the thickness of 1 is preferably 2 mm.

In the wiring layer 1, the ratio of the thickness of the composite material layer 2 to the thickness of the pure aluminum layer 3 is not limited, but is preferably 1:10 to 10: 1, particularly 1: 5 to 5: 1. Good to be.

Although the thickness of the composite material layer 2 is not limited, it is desirable to be as thick as possible. The reason is that the thermal conductivity of the wiring layer 1 can be surely improved, the linear expansion coefficient of the wiring layer 1 can be surely made close to the linear expansion coefficient of the semiconductor chip 21 and the solder layer 22, and moreover This is because generation of wrinkles in the mounting surface 1 a due to thermal stress between the aluminum layer 3 and the insulating layer 4 can be suppressed. Therefore, the thickness of the composite material layer 2 is preferably 100 μm or more. In particular, the thickness of the composite material layer 2 is preferably 200 μm or more. In this case, the occurrence of wrinkles on the mounting surface 1a can be reliably suppressed. The upper limit of the thickness of the composite material layer 2 is not limited and is usually 1 mm.

The thickness of the pure aluminum layer 3 is not limited. However, when the pure aluminum layer 3 is too thick, the pure aluminum layer 3 becomes a thermal resistance, and when the pure aluminum layer 3 is too thin, the effect of alleviating the thermal stress described above decreases. From this point of view, the thickness of the pure aluminum layer 3 is desirably in the range of 100 μm to 1.5 mm. When the thickness of the pure aluminum layer 3 is 100 μm or more, the above-described effect of the thermal stress can be reliably exhibited. By setting the thickness of the pure aluminum layer 3 to 1.5 mm or less, the decrease in the thermal conductivity of the wiring layer 1 due to the pure aluminum layer 3 can be reliably suppressed, and the wiring layer 1 has high thermal conductivity. It can be maintained reliably. The upper limit of the thickness of the particularly desirable pure aluminum layer 3 is 1 mm.

The purity of aluminum of the pure aluminum layer 3 is 99% or more as described above. As such aluminum, A1100, A1050, A1N30, etc. are suitably used. In order to further improve the reliability against thermal stress in the insulating substrate 6 and the heat dissipation device 10A, the purity of aluminum is desirably 99.9% or more, and particularly 99.99% or more. As such aluminum, high purity aluminum, ultra high purity aluminum or the like is used. The upper limit of the purity of aluminum is not limited and is, for example, 99.999%.

The composite material of the composite material layer 2 is an aluminum-carbon particle composite material as described above, and specifically includes an aluminum matrix 11 and a large number of carbon particles 12 dispersed in the aluminum matrix 11. The material of the aluminum of the aluminum matrix 11 is not limited, and may be, for example, a pure aluminum-based aluminum alloy having a purity of 99%, such as A1100, A1050, A1N30. In order to enhance the reliability against the thermal stress of the insulating substrate 6 and the heat dissipation device 10A, the purity of the aluminum of the aluminum matrix 11 is desirably 99.9% or more, and preferably 99.99% or more.

The type of carbon particle 12 is not limited. In particular, it is desirable to use, as the carbon particles 12, one or two or more kinds selected from the group consisting of carbon fibers, carbon nanotubes, natural graphite particles and graphene. The reason is that such carbon particles have high thermal conductivity and are easily complexed with aluminum.

As carbon fibers, pitch-based carbon fibers, PAN-based carbon fibers and the like are suitably used.

As carbon nanotubes, single-walled carbon nanotubes, multi-walled carbon nanotubes, vapor grown carbon fibers (including VGCF (registered trademark)), and the like are suitably used.

As natural graphite particles, scale-like graphite particles (in particular, high thermal conductive scale-like graphite particles) are preferably used.

As graphene, single-layer graphene, multilayer graphene, or the like is preferably used.

The size of the carbon particles 12 is not limited, and the average length of the carbon particles 12 in the longest axis direction is usually in the range of 1 μm to 1 mm.

The linear expansion coefficient of the composite material layer 2 is preferably smaller than that of the pure aluminum layer 3, specifically 18 ppm / K or less, and particularly preferably 15 ppm / K or less. Furthermore, the linear expansion coefficient of the composite layer 2 is desirably 2 ppm / K or more. In this case, the generation of thermal stress between the composite material layer 2 and the solder layer 22 due to the linear expansion coefficient of the composite material layer 2 being too smaller than the linear expansion coefficient of the solder layer 22 can be reliably suppressed.

The manufacturing method of the composite material layer 2 is not limited. As a manufacturing method thereof, as described in JP-A-2015-25158 and the like, a laminate (preform body) in a state in which a plurality of preform foils in which a large number of carbon particles are attached is laminated on an aluminum foil is A method of producing a composite material layer by heating and sintering in a plate shape while pressing in the laminating direction of the reform foil (this manufacturing method is referred to as “preform foil lamination sintering method” for convenience of explanation), and aluminum powder A method of producing a composite material layer by heating and sintering a mixture with carbon powder as carbon particles in a plate shape while pressing in one direction (this method is referred to as “powder sintering method” for convenience of explanation) is mentioned Be

In the present embodiment, the composite layer 2 is manufactured by the former method (preform foil lamination sintering method), and further, the composite layer 2 and the pure aluminum layer 3 are sintered simultaneously with the manufacture of the composite layer 2. It is joined. This method is described below.

As shown in FIG. 2, a plurality of preform foils 14 in which a large number of carbon particles 12 are attached on an aluminum foil 13 are prepared. In the present embodiment, the carbon particles 12 are attached to the lower surface of the aluminum foil 13 by a binder resin (not shown). The thickness of the aluminum foil 13 is usually in the range of 5 to 100 μm. Then, a plurality of preform foils 14 are laminated to form a laminate body 17a, and a pure aluminum layer 3 made of a pure aluminum plate having a purity of 99% or more is formed on the laminate body 17a below the laminate body 17a. The lamination is performed to form a lamination 17 including the lamination body 17 a and the pure aluminum layer 3.

Then, the laminate 17 is heated and sintered in a predetermined sintering atmosphere while pressing the laminate 17 in the lamination direction of the preform foil 14 (that is, the thickness direction of the laminate 17) to produce the composite material layer 2 at the same time The composite layer 2 and the pure aluminum layer 3 are sintered and bonded.

The sintering atmosphere is preferably a non-oxidizing atmosphere. The non-oxidizing atmosphere includes an inert gas atmosphere (eg, nitrogen gas atmosphere, argon gas atmosphere), a vacuum atmosphere, and the like.

It is desirable that such sintering of the laminate 17 be performed by a vacuum hot press sintering method, a discharge plasma sintering method, or the like. The specific example in the case of sintering the laminated body 17 by the vacuum hot press sintering method is demonstrated below.

As shown in FIG. 3, a vacuum hot-press sintering apparatus 30 is prepared which comprises a receiving mold 31, a pressing punch 32, a cylindrical peripheral mold 33, a heater (not shown) and the like. Then, the stacked body 17 is disposed in the circumferential mold 3, and the stacked body 17 is received by the receiving mold 31 from the lower side thereof.

Next, the laminate 17 is heated by the heater in a vacuum atmosphere while being pressed by the pressing punch 32 in the stacking direction of the preform foil 14 (the pressing direction P thereof), thereby stacking the stack 17 The body 17a is sintered to obtain the composite layer 2, and at the same time the composite layer 2 and the pure aluminum layer 3 are sintered and joined. Thereby, the above-mentioned wiring layer 1 is obtained.

In the composite material layer 2 of the wiring layer 1, the material of the aluminum foil 13 becomes the aluminum matrix 11 and penetrates between the

carbon particles

12, 12 by being pressurized and heated as described above. The air gap between 12 and 12 disappears. As a result, in the composite material layer 2, the carbon particles 12 are dispersed in the aluminum matrix 11.

The binder resin contained in the laminate 17 is eliminated by sublimation, decomposition, and the like on the way of heating the laminate 17 so that the temperature of the laminate 17 rises from approximately room temperature to the sintering temperature, and is removed from the laminate 17 Ru.

The desirable sintering conditions in the case of sintering by the vacuum hot press sintering method are as follows.

The sintering temperature is 450 to 640 ° C., the sintering time (ie, the holding time of the sintering temperature) is 10 to 300 minutes, the pressure applied to the laminate is 1 to 40 MPa, and the degree of vacuum is 10 -4 to 10 Pa.

Next, a method of manufacturing the heat dissipation device 10A will be described below.

As shown in FIG. 4, the wiring layer 1, the insulating layer 4 and the first buffer layer 5 are stacked. At this time, brazing material foils 18 are interposed between the wiring layer 1 and the insulating layer 4 and between the insulating layer 4 and the first buffer layer 5, respectively. Then, these

layers

1, 4, and 5 are integrally joined in a laminated state by brazing. Thereby, the insulating substrate 6 shown in FIG. 5 is obtained.

Next, the insulating substrate 6, the second buffer layer 7A, and the heat dissipation member 8 are stacked. And these are joined and integrated in lamination form by brazing. Thereby, the heat dissipation device 10A shown in FIG. 1 is obtained.

FIG. 6 is a view for explaining a heat dissipation device 10B according to a second embodiment of the present invention. In addition, in this figure, the same code | symbol as the code | symbol attached | subjected to the element of the heat radiating device 10A of the said 1st Embodiment is attached | subjected to the element which plays the same effect as the element of the heat radiating device 10A of the said 1st embodiment.

In the heat dissipation device 10B of the second embodiment, the second buffer layer 7B is not made of an aluminum punching metal plate, but is made of a double-sided aluminum brazing sheet provided with a brazing material layer (not shown) on each side. is there. Then, the second buffer layer 7B is joined to the first buffer layer 5 in one brazing material layer of the brazing sheet, and the second buffer layer 7B is joined to the heat dissipation member 8 in the other brazing material layer of the brazing sheet. There is. The other configuration is the same as that of the heat dissipation device 10A of the first embodiment.

Although some embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, although the heat radiating member 8 is liquid cooled in the above embodiment, the heat radiating member may be, for example, air cooled (eg, heat sink) in the present invention.

Further, in the above embodiment, the composite material layer 2 and the pure aluminum layer 3 in the wiring layer 1 are sintered and joined, but in the present invention, the

layers

2 and 3 may be brazed, for example.

The present application relates to priority claim of Japanese Patent Application No. 2017-227442 filed on November 28, 2017, and the disclosure content thereof constitutes a part of the present application as it is. .

The terms and phrases used herein are for the purpose of description, not for limitation, but any equivalent of the features shown and described herein. It should also be recognized that it is not excluded and that various modifications within the claimed scope of the present invention are also permitted.

Although the present invention can be embodied in many different forms, this disclosure is to be considered as providing examples of the principles of the present invention, which examples are intended to illustrate the present invention. With the understanding that it is not intended to be limited to the preferred embodiments described and / or illustrated herein, a number of illustrated embodiments are described herein.

Although several illustrated embodiments of the present invention are described herein, the present invention is not limited to the various preferred embodiments described herein, but is equivalent based on this disclosure and may be appreciated by those skilled in the art. The present invention also includes any and all embodiments that have various elements, modifications, deletions, combinations (eg, combinations of features across various embodiments), improvements and / or changes. The limitations of the claims should be interpreted broadly based on the terms used in the claims, and should not be limited to the embodiments described in the specification or process of the present application, and such The examples should be construed as non-exclusive. For example, in the present disclosure, the term "preferentially" is non-exclusive and means "preferably, but not limited to."

Next, specific examples of the present invention and comparative examples are shown below. However, the present invention is not limited to the following examples.

Example 1
In Example 1, the heat dissipation device 10B shown in FIG. 6 was prepared.

The plan view shape of the wiring layer 1 of the heat dissipation device 10B was a square of 28 mm long × 28 mm wide, and the thickness of the wiring layer 1 was 600 μm.

The upper portion of the wiring layer 1 including the mounting surface 1a is made of an aluminum-carbon particle composite layer 2 with a thickness of 400 μm. The material of the aluminum of the aluminum matrix 11 of the composite material layer 2 was pure aluminum having a purity of 99.99%. The entire portion of the wiring layer 1 below the composite material layer 2 is made of a pure aluminum layer having a thickness of 200 μm and a purity of 99.99%.

The insulating layer 4 was made of an aluminum nitride (AlN) plate, and its shape in plan view was a square of 30 mm long × 30 mm wide, and its thickness was 640 μm.

The first buffer layer 5 was made of a pure aluminum plate having a purity of 99.99%, and its shape in a plan view was 28 mm long × 28 mm wide, and its thickness was 600 μm.

The second buffer layer 7B was a double-sided aluminum brazing sheet, and its shape in a plan view was 29 mm long × 29 mm wide, and its thickness was 600 μm.

The heat dissipation member 8 was made of aluminum and had a thickness of 10 mm.

A thermal cycle test was conducted 500 cycles at a test temperature range of −40 ° C. to 200 ° C. for the heat dissipation device 10B. And when the state of the mounting surface 1a of the wiring layer 1 was observed, no wrinkles were generated on the mounting surface 1a.

Example 2
In the heat dissipation device 10B prepared in the second embodiment, the upper portion of the wiring layer 1 including the mounting surface 1a is made of the aluminum-carbon particle composite material layer 2 having a thickness of 200 μm, and is lower than the composite material layer 2 in the wiring layer 1 The whole of the part consists of a pure aluminum layer 3 with a thickness of 400 μm and a purity of 99.99%. The other configuration is the same as the heat dissipation device 10B of the first embodiment.

A thermal cycle test was conducted on the heat dissipation device 10B under the same test conditions as in Example 1. And when the state of the mounting surface 1a of the wiring layer 1 was observed, almost no wrinkles were generated on the mounting surface 1a.

Example 3
In the heat dissipation device 10B prepared in the third embodiment, the upper portion including the mounting surface 1a in the wiring layer 1 is made of the aluminum-carbon particle composite material layer 2 having a thickness of 100 μm, and is lower than the composite material layer 2 in the wiring layer 1 The whole of the part consists of a pure aluminum layer 3 with a thickness of 500 μm and a purity of 99.99%. The other configuration is the same as the heat dissipation device 10B of the first embodiment.

A thermal cycle test was conducted on the heat dissipation device 10B under the same test conditions as in Example 1. And when the state of the mounting surface 1a of the wiring layer 1 was observed, the wrinkles had slightly generate | occur | produced on the mounting surface 1a.

Comparative Example
In the heat dissipation device prepared in this comparative example, the entire wiring layer is made of a pure aluminum layer having a thickness of 600 μm and a purity of 99.99%. The other configuration is the same as the heat dissipation device 10B of the first embodiment.

A thermal cycle test was conducted on the heat dissipation device under the same test conditions as in Example 1. Then, when the state of the mounting surface of the wiring layer was observed, a slight wrinkle was generated on the mounting surface.

The present invention is applicable to an insulating substrate and a heat dissipation device on which a heat generating element such as an electronic element (for example, a semiconductor chip) is mounted.

1: Wiring layer 1a: Mounting surface 2: Aluminum-carbon particle composite material layer 3: Pure aluminum layer 4: Insulating layer 5: First buffer layer 6: Insulating

substrate

7A, 7B: Second buffer layer 8:

Heat dissipation member

10A, 10B: Heat dissipation device 21: Semiconductor chip (heat generating element)

Claims

A wiring layer having a mounting surface for a heat generating element formed of an upper surface, and an insulating layer disposed below the wiring layer in a stacked manner with respect to the wiring layer;
The upper portion of the wiring layer has an aluminum-carbon particle composite layer,
An insulating substrate, wherein a portion of the wiring layer below the composite material layer has a pure aluminum layer with a purity of 99% or more.
The insulating substrate according to claim 1, wherein the purity of aluminum of the pure aluminum layer is 99.99% or more.
The insulating substrate according to claim 1, wherein a thickness of the composite material layer is 100 μm or more.
A heat dissipation device comprising the insulating substrate according to any one of claims 1 to 3 and a heat dissipation member.