JP2023107225A - Laminate and semiconductor device - Google Patents

Abstract

To provide a laminate with low thermal resistance value and excellent pattern processability.SOLUTION: A laminate 13 includes a metal base plate 11, a second resin layer 10b, a thermally conductive intermediate layer 18, a first resin layer 10a, and a metal sheet 12, in this order. The metal sheet 12 has a thickness of 1.4 mm or less. The thickness of the thermally conductive intermediate layer 18 is 0.2 mm or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminate and a semiconductor device having the laminate.

2. Description of the Related Art Conventionally, power devices have been used in a wide range of fields such as industrial equipment, household electrical equipment, and information terminals. Attempts have been made to use laminates having resin layers as substrates in power devices, which are expected to be used in high voltage applications, for example. From the standpoint of miniaturization of power devices in the future, etc., there is an increasing demand for higher heat dissipation (lower thermal resistance) for laminates including the resin layer.

Patent Document 1 discloses a composite member (laminate) having a heat-dissipating base substrate, a thermally conductive insulating adhesive member (resin layer) containing a thermally conductive filler and a binder resin, and a heating element containing a member capable of generating heat. Patent Document 1 describes an invention relating to the above, and describes that a metal plate may be provided between the resin layer and the heating element. A copper block having a thickness of 2 mm is exemplified as the metal plate.

JP 2017-168825 A

When the thickness of the metal plate is large, heat is diffused not only in the stacking direction but also in the plane direction of the metal plate, so that the heat resistance value of the entire laminate is low and the heat dissipation is excellent. However, when a pattern is formed by etching a metal plate with an etchant or the like, a taper is formed at the etched portion, making it difficult to form a pattern with a narrow interval. In addition, as a method for forming a pattern by a method other than etching, there is a method of arranging individualized thick metal pieces, but in this case, the positional accuracy of the pattern and the adhesiveness of the pattern deteriorate. Thus, if the metal plate is thick, it is excellent in terms of heat dissipation, but there is room for improvement in terms of pattern workability.
From such a point of view, an object of the present invention is to provide a laminate having a low thermal resistance value and excellent pattern workability.

The present inventors have made intensive studies in order to achieve the above object. As a result, a metal base plate, a second resin layer, a heat-conducting intermediate layer, a first resin layer, and a metal plate are provided in this order, and the thickness of the metal plate and the thickness of the heat-conducting intermediate layer are set within specific ranges. The inventors have found that the above-mentioned problems can be solved by a laminate having the above structure, and have completed the present invention.
That is, the present invention relates to the following [1] to [17].

[1] A metal base plate, a second resin layer, a heat-conducting intermediate layer, a first resin layer, and a metal plate in this order, wherein the metal plate has a thickness of 1.4 mm or less, and the heat-conducting intermediate layer A laminate having a thickness of 0.2 mm or more.
[2] The above [1], wherein the ratio of the thickness of the first resin layer to the total thickness of the first resin layer and the second resin layer is 0.05 or more and 0.9 or less. laminate.
[3] The laminate according to [2] above, wherein the total thickness of the first resin layer and the second resin layer is 0.01 mm or more and 0.3 mm or less.
[4] the thermally conductive intermediate layer is a first thermally conductive intermediate layer;
The above [1] comprising a metal base plate, a third resin layer, a second heat conductive intermediate layer, a second resin layer, a first heat conductive intermediate layer, a first resin layer, and a metal plate in this order. The laminated body according to any one of [3] [5] The total thickness of the first resin layer, the second resin layer and the third resin layer is 0.02 mm or more and 0.5 mm or less The laminate according to [4] above.
[6] The laminate according to any one of [1] to [5] above, wherein at least one of the resin layers included in the laminate is an insulating resin layer.
[7] The laminate according to any one of [1] to [6] above, wherein at least one of the resin layers included in the laminate has a thermal conductivity of 3 W/(m K) or more. .
[8] The laminate according to any one of [1] to [7] above, wherein at least one of the resin layers included in the laminate contains an inorganic filler and a binder resin.
[9] The laminate according to [8] above, wherein the binder resin contains a thermosetting resin and a curing agent, and the thermosetting resin contains an epoxy resin.
[10] The laminate according to the above [8] or [9], wherein the inorganic filler contains boron nitride particles.
[11] The laminate according to any one of [8] to [10] above, wherein the resin layer containing the inorganic filler has an inorganic filler content of 50% by volume or more and 90% by volume or less.
[12] The laminate according to any one of [8] to [11] above, wherein the inorganic filler contains an inorganic filler other than boron nitride particles.
[13] The laminate according to [12] above, wherein the inorganic filler other than the boron nitride particles is at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide.
[14] The laminate according to any one of [1] to [13] above, wherein the heat conductive intermediate layer has a heat conductivity of 100 W/(m·K) or more.
[15] The laminate according to any one of [1] to [14] above, wherein the heat conductive intermediate layer contains at least one selected from the group consisting of copper, aluminum nitride, and silicon nitride.
[16] The laminate according to any one of [1] to [15] above, wherein the metal plate is a metal plate having a circuit pattern.
[17] A semiconductor device comprising the laminate of [16] above and a semiconductor element provided on a metal plate having a circuit pattern of the laminate.

According to the present invention, it is possible to provide a laminate having a low thermal resistance value and excellent pattern workability.

It is a typical sectional view showing a layered product concerning one embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a laminate according to another embodiment of the invention; 1 is a schematic cross-sectional view showing a semiconductor device according to one embodiment of the present invention; FIG. It is a figure which shows typically the evaluation method of pattern processability.

<Laminate>
The laminate of the present invention comprises a metal base plate, a second resin layer, a heat-conducting intermediate layer, a first resin layer, and a metal plate in this order, the thickness of the metal plate being 1.4 mm or less, and the The heat-conducting intermediate layer has a thickness of 0.2 mm or more.
Since the laminate of the present invention has the above structure, the heat from the heating element can be three-dimensionally diffused without increasing the thickness of the metal plate. As a result, the thermal resistance value of the entire laminate is kept low, and the heat dissipation is excellent.

A laminate of the present invention will be described with reference to the drawings. In addition, the present invention is not limited to the contents of the drawings.
FIG. 1 shows a schematic cross-sectional view of one embodiment of the laminate of the present invention. A laminate 13 of the present invention includes a second resin layer 10b, a heat-conducting intermediate layer 18, a first resin layer 10a, and a metal plate 12 on a metal base plate 11 in this order. The metal plate 12 may be a metal plate having a circuit pattern on which a pattern is formed by a known method such as etching.

A heating element such as a semiconductor element is arranged on the metal plate 12 of the laminate 13, and the heat generated by the heating element is transferred to the metal plate 12, the first resin layer 10a, the heat-conducting intermediate layer 18, and the second heat-conducting layer. Heat is dissipated through the resin layer 10b and the metal base plate 11 in this order.
In the laminate 13 of the present invention, the metal plate 12 has a thickness of 1.4 mm or less, and the heat conductive intermediate layer has a thickness of 0.2 mm or more. This makes it possible to provide a laminate having a low thermal resistance value and excellent pattern workability.

Further, although the details will be described later, as another embodiment of the laminate of the present invention, as shown in FIG. The laminate may be a laminate comprising the resin layer 10b, the first heat-conducting intermediate layer 18a, the first resin layer 10a, and the metal plate 12 in this order. The first heat-conducting intermediate layer 18a corresponds to the heat-conducting intermediate layer 18 described in FIG.
Each member will be described in detail below.

<Metal plate>
The metal plate included in the laminate of the present invention has a thickness of 1.4 mm or less. If the thickness of the metal plate is more than 1.4 mm, taper occurs during pattern formation, making it difficult to form patterns with narrow intervals, and pattern workability deteriorates.
The thickness of the metal plate is preferably 1.2 mm or less, more preferably 1.0 mm or less, and even more preferably 0.9 mm or less. By setting the thickness of the metal plate to a certain value or less in this manner, the pattern workability is improved. Also, the thickness of the metal plate is preferably 0.2 mm or more, more preferably 0.4 mm or more, and still more preferably 0.6 mm or more. By setting the thickness of the metal plate to a certain value or more in this manner, the thermal resistance value of the laminate can be easily lowered, and the heat dissipation can be improved.

Since the metal plate functions as a heat conductor, the heat conductivity thereof is preferably 10 W/m·K or more. Materials used for the metal plate include metals such as aluminum, copper, gold, and silver, and graphite sheets. From the viewpoint of more effectively increasing thermal conductivity, aluminum, copper, or gold is preferred, aluminum or copper is more preferred, and copper is even more preferred.

Metal plate 12 is preferably used as a circuit board. When used as a circuit board, the metal plate 12 in the laminate 13 may have a circuit pattern. The circuit pattern may be appropriately patterned according to the elements to be mounted on the circuit board. The circuit pattern is not particularly limited, but may be formed by etching or the like. Since the metal plate of the present invention has a thickness of a certain value or less as described above, it is excellent in pattern workability.

<Heat conduction intermediate layer>
The laminate of the invention comprises a heat-conducting intermediate layer. The heat-conducting intermediate layer is arranged between a first resin layer and a second resin layer, which will be described later. The thickness of the heat-conducting intermediate layer is 0.2 mm or more. When the thickness of the heat-conducting intermediate layer is less than 0.2 mm, three-dimensional heat diffusion is difficult to occur.
From the viewpoint of lowering the heat resistance value of the laminate, the thickness of the heat-conducting intermediate layer is preferably 0.3 mm or more, more preferably 0.6 mm or more, and still more preferably 0.8 mm or more. The thickness of the thermally conductive intermediate layer is preferably 3 mm or less, more preferably 2.0 mm or less, and even more preferably 1.5 mm or less from the viewpoint of thinning the laminate.
The heat conductive intermediate layer preferably has a heat conductivity of 100 W/(m·K) or more, more preferably 150 W/(m/K) or more. When the thermal conductivity of the heat-conducting intermediate layer is above a certain level, the heat is diffused three-dimensionally in the heat-conducting intermediate layer, which tends to lower the thermal resistance value of the laminate. The thermal conductivity of the thermally conductive intermediate layer is the thermal conductivity in the thickness direction. The thermal conductivity of the thermal conductive intermediate layer is measured by a laser flash method.

The heat conductive intermediate layer is preferably a layer containing metal or ceramic, and more preferably contains at least one selected from the group consisting of copper, aluminum nitride, and silicon nitride from the viewpoint of improving heat dissipation. Among them, the heat-conducting intermediate layer is preferably made of copper or aluminum nitride, and more preferably made of copper. If the heat-conducting intermediate layer is metal such as copper, for example, a plate-shaped metal can be used as the heat-conducting intermediate layer. If the heat-conducting intermediate layer is made of ceramic such as aluminum nitride or silicon nitride, the heat-conducting intermediate layer can be, for example, a plate-shaped ceramic or a ceramic pressed body obtained by pressing ceramic powder. The ceramic pressed body can be formed, for example, by disposing ceramic powder (aluminum nitride powder, silicon nitride powder, etc.) between the first resin layer and the second resin layer and pressing under heat. can.

In addition, a plurality of thermally conductive intermediate layers may be arranged in the laminate, and a first thermally conductive intermediate layer arranged between a first resin layer and a second resin layer to be described later, and a first thermally conductive intermediate layer to be described later. A second heat-conducting intermediate layer disposed between the two resin layers and the third resin layer. In this case, the characteristics such as thickness, thermal conductivity, and material of the first heat-conducting intermediate layer and the second heat-conducting intermediate layer are the same as those of the heat-conducting intermediate layer described above.

<Resin layer>
A laminate of the present invention comprises a first resin layer and a second resin layer, and the heat-conducting intermediate layer described above is provided between the first resin layer and the second resin layer. With such a configuration, it becomes easier to improve the heat dissipation of the laminate.

At least one of the resin layers included in the laminate of the present invention is preferably an insulating resin layer. Thereby, the electrical insulation of the laminate can be improved, and the reliability as a product can be enhanced.

Of the resin layers included in the laminate of the present invention, the thermal conductivity of at least one resin layer is preferably 3 W / (m K) or more, more preferably 7 W / (m K) or more, It is more preferably 10 W/(m·K) or more, more preferably 15 W/(m·K) or more. Thereby, the heat dissipation property of a laminated body can be improved. Thermal conductivity is measured by the laser flash method.

From the viewpoint of improving the heat dissipation of the laminate, the thermal conductivity of at least one of the first resin layer and the second resin layer is preferably 3 W/(mK) or more, more preferably It is 7 W/(m·K) or more, more preferably 10 W/(m·K) or more, further preferably 15 W/(m·K) or more.
In addition, from the viewpoint of further improving the heat dissipation of the laminate, the thermal conductivity of both the first resin layer and the second resin layer is preferably 3 W / (m K) or more. It is preferably 7 W/(m·K) or more, more preferably 10 W/(m·K) or more, further preferably 15 W/(m·K) or more.
The thermal conductivity of the first and second resin layers is measured by a laser flash method.

At least one of the first resin layer and the second resin layer is preferably an insulating resin layer, and both resin layers are preferably insulating resin layers. Thereby, the electrical insulation of the laminate can be improved, and the reliability as a product can be enhanced.
Here, the insulating resin layer is a resin layer containing an insulating filler to be described later as an inorganic filler. The insulating filler is a filler having a volume resistivity of 10 ⁶ Ω·cm or more. Details of the inorganic filler will be described later.

Further, when the laminate includes a first resin layer, a second resin layer and a third resin layer, at least one of the first resin layer, the second resin layer and the third resin layer The thermal conductivity of the resin layer is preferably 3 W/(m·K) or more, more preferably 7 W/(m·K) or more, still more preferably 10 W/(m·K) or more, and It is preferably 15 W/(m·K) or more.
Further, from the viewpoint of further improving the heat dissipation of the laminate, the thermal conductivity of all the resin layers of the first resin layer, the second resin layer and the third resin layer is preferably 3 W / (m K ) or more, more preferably 7 W/(m·K) or more, still more preferably 10 W/(m·K) or more, still more preferably 15 W/(m·K) or more.
At least one of the first resin layer, the second resin layer, and the third resin layer is preferably an insulating resin layer, and all the resin layers are preferably insulating resin layers. preferable. Thereby, the electrical insulation of the laminate can be improved, and the reliability as a product can be enhanced.

Ratio of the thickness of the first resin layer to the total thickness of the first resin layer and the second resin layer [thickness of the first resin layer / (total thickness of the first resin layer and the second resin layer thickness)] is preferably 0.05 or more and 0.9 or less. The ratio of the thickness of the first resin layer to the total thickness of the first resin layer and the second resin layer may be hereinafter simply referred to as "the ratio of the thickness of the resin layer".
When the thickness ratio of the resin layers is within the above range, the heat-conducting intermediate layer is arranged at a position closer to the metal plate, which makes it easier to reduce the heat resistance value of the laminate.
The thickness ratio of the resin layers is preferably 0.5 or less, more preferably 0.3 or less, from the viewpoint of reducing the thermal resistance of the laminate. , preferably 0.05 or more, more preferably 0.2 or more.
The thicknesses of the first resin layer and the second resin layer are each preferably 10 μm or more, more preferably 30 μm or more, and preferably 150 μm or less, more preferably 100 μm or less. The thickness of the first resin layer and the thickness of the second resin layer may be the same or different, but the thickness of the first resin layer is thinner than the thickness of the second resin layer. is preferred. This makes it easier to adjust the thickness ratio of the resin layers as described above, and as a result, it becomes easier to lower the thermal resistance value of the laminate.
The total thickness of the first resin layer and the second resin layer is not particularly limited, but is preferably 0.01 mm or more from the viewpoint of improving the insulation property of the laminate and reducing the thermal resistance value. It is more preferably 0.015 mm or more, preferably 0.3 mm or less, and more preferably 0.2 mm or less.
The total thickness of the first resin layer, the second resin layer and the third resin layer is not particularly limited. 0.02 mm or more, more preferably 0.05 mm or more, and preferably 0.5 mm or less, more preferably 0.3 mm or less.

At least one of the resin layers included in the laminate of the present invention preferably contains an inorganic filler and a binder resin.

At least one of the first resin layer and the second resin layer preferably contains an inorganic filler and a binder resin, and both the first resin layer and the second resin layer contain an inorganic filler and a binder resin. It is more preferable to contain a binder resin.

In addition, when a plurality of heat-conducting intermediate layers are arranged, the laminate of the present invention may further include a third resin layer. Two heat-conducting intermediate layers are provided. With such a configuration, it becomes easier to improve the heat dissipation of the laminate. The characteristics of the third resin layer, such as thermal conductivity, material, and thickness, are the same as those of the first resin layer and the second resin layer.

When the laminate includes a first resin layer, a second resin layer, and a third resin layer, at least one of the first resin layer, the second resin layer, and the third resin layer preferably contains an inorganic filler and a binder resin, and more preferably all resin layers contain an inorganic filler and a binder resin.
In addition, when simply described as a "resin layer" hereinafter, it means at least one resin layer or all the resin layers provided in the laminate.

(Inorganic filler)
From the viewpoint of improving the heat dissipation of the resin layer, the inorganic filler preferably contains a filler having a thermal conductivity of 10 W/m·K or more, and more preferably contains boron nitride particles. The boron nitride particles correspond to the insulating filler described above, and the resin layer containing the boron nitride particles becomes the insulating resin layer.
The content of boron nitride particles in the resin layer containing boron nitride particles is preferably 10% by volume or more, more preferably 15% by volume or more, and still more preferably 20% by volume, from the viewpoint of improving the heat dissipation of the resin layer. % or more, preferably 90% by volume or less, more preferably 85% by volume or less, and even more preferably 80% by volume or less.

The average length of the primary particles of the boron nitride particles is not particularly limited, but is preferably 1 μm or more, more preferably 1.5 μm or more, still more preferably 2.0 μm or more, and more preferably 30 μm or less, and more preferably It is 20 μm or less, more preferably 15 μm or less.
The average aspect ratio determined by the major axis and minor axis of the primary particles of boron nitride particles is preferably 1 or more, more preferably 2 or more, and preferably 8 or less, more preferably 7 or less.
The average aspect ratio and average major axis are obtained from the major axis and minor axis of the primary particle diameter of the boron nitride particles measured in the cross section exposed by the cross-section polisher. Specifically, it is as follows.
First, a cross-section polisher is used to expose a cross-section of the resin layer, and the exposed cross-section is observed with a scanning electron microscope (SEM) at a magnification of 400 to 1200 to obtain an observed image. In the observation image, using image analysis software, the major diameter and minor diameter of the primary particles of 200 boron nitride particles are randomly measured, and the aspect ratio of each particle is calculated from the major diameter / minor diameter. Let the average value of 1 be the average aspect. Also, the average value of the major diameters of the measured 200 primary particles is defined as the average major diameter. The major diameter is the length of the longest portion of the observed primary particles of the boron nitride particles in the observation image. Also, the minor axis is the length in the direction perpendicular to the major axis direction in the observed image.

The boron nitride particles preferably comprise boron nitride agglomerate particles. Agglomerated boron nitride particles are aggregated particles formed by aggregating primary particles.
Boron nitride agglomerated particles can generally be determined whether they are agglomerated particles, for example, by cross-sectional observation with an SEM. The aggregated boron nitride particles may maintain the shape of the aggregated particles, or may be deformed, disintegrated, or crushed through various processes such as press molding. However, after being mixed with a binder resin, the aggregated boron nitride particles are subjected to a process such as press molding, so that even if they are deformed, collapsed, crushed, etc., they are generally not oriented, and they exist in a certain amount of aggregation. Therefore, for example, by observing the cross section described above, it is suggested that the particles are boron nitride agglomerated particles, and it can be determined whether or not they are agglomerated particles.

The aggregated boron nitride particles incorporated in the resin layer preferably have an average particle size of 5 μm or more, more preferably 10 μm or more, from the viewpoint of effectively improving insulation and thermal conductivity. It is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less.
The average particle size of aggregated particles can be measured by a laser diffraction/scattering method. Regarding the method of calculating the average particle size, the particle size (d50) of aggregated particles when the cumulative volume is 50% is adopted as the average particle size.

The method for producing the aggregated boron nitride particles is not particularly limited, and can be produced by a known method. For example, it can be obtained by aggregating (granulating) primary particles prepared in advance, and specific examples thereof include a spray drying method and a fluid bed granulation method. The spray drying method (also called spray drying) can be classified into a two-fluid nozzle method, a disk method (also called a rotary method), an ultrasonic nozzle method, etc., and any of these methods can be applied.
Moreover, the granulation step is not necessarily required as a method for producing aggregated boron nitride particles. For example, as boron nitride crystals crystallized by a known method grow, the primary particles of boron nitride naturally aggregate to form agglomerated particles.
Examples of aggregated boron nitride particles include “UHP-G1H” manufactured by Showa Denko KK, “HP-40” manufactured by Mizushima Ferroalloy Co., Ltd., and the like.

The inorganic filler may consist of only boron nitride particles, or may contain an inorganic filler other than boron nitride. As an inorganic filler other than boron nitride particles, a thermally conductive filler may be used. The thermally conductive filler has, for example, a thermal conductivity of 10 W/(m·K) or more, preferably 15 W/(m·K) or more, more preferably 20 W/(m·K) or more. Moreover, although the upper limit of the thermal conductivity of the thermally conductive filler is not particularly limited, it may be, for example, 300 W/(m·K) or less, or 200 W/(m·K) or less. Inorganic fillers other than boron nitride particles can enter interstices between boron nitride particles, such as boron nitride agglomerate particles, to enhance thermal conductivity.
The thermal conductivity of the inorganic filler can be measured, for example, by a periodic heating thermoreflectance method using a thermal microscope manufactured by Bethel Co., Ltd. on a cross section of the filler cut by a cross section polisher.

The inorganic filler other than boron nitride particles is preferably at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide. Each of these fillers corresponds to the insulating filler described above. By using these inorganic fillers, good thermal conductivity is maintained, deterioration of insulation is prevented, and adhesion to a metal plate is easily improved. Alumina is preferable among the above from the viewpoint of preventing deterioration of insulating properties while keeping thermal conductivity and adhesion to a metal plate at a high level.
Moreover, as inorganic fillers other than boron nitride particles, one type may be used alone, or two or more types may be used in combination.

The inorganic filler other than the boron nitride particles may be of any shape, and may be scaly, spherical, crushed, amorphous, polygonal, or aggregated particles. However, the inorganic filler other than the boron nitride particles preferably has an average aspect ratio of primary particles of 3 or less. Examples of such fillers include spherical fillers. Spherical alumina is more preferable as the spherical filler. The average aspect ratio of primary particles can be measured by cross-sectional observation as described above.
The average aspect ratio of inorganic fillers other than boron nitride particles is more preferably 2 or less. The inorganic filler other than boron nitride particles may have an aspect ratio of 1 or more. The use of inorganic fillers other than boron nitride particles having such a low aspect ratio makes it easier to improve thermal conductivity and adhesion to metal plates.

The average particle size of the inorganic filler other than the boron nitride particles is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. Also, it is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 70 μm or less. When the average particle size is less than these upper limits, it becomes easier to mix the inorganic filler in the resin sheet at a high filling rate. Moreover, when it is more than a lower limit, it will become easy to improve insulation. The average particle size of inorganic fillers other than boron nitride particles can be measured, for example, by the Coulter Counter method.

When the resin layer contains an inorganic filler other than boron nitride particles, the content of the inorganic filler other than the boron nitride particles is, for example, 2% by volume or more and 55% by volume or less based on the total amount of the resin layer containing the inorganic filler. . By adjusting the content to such a value, for example, thermal conductivity and adhesion to a metal plate can be enhanced. The content of the inorganic filler other than the boron nitride particles is preferably 4% by volume or more, more preferably 10% by volume or more, and preferably 70% by volume or less, more preferably 65% by volume or less.

When an inorganic filler other than boron nitride particles is included, the volume ratio of the inorganic filler other than boron nitride particles to the boron nitride particles (inorganic filler other than boron nitride particles/boron nitride particles) is, for example, 0.001 or more 4 It is below. By setting the thickness within this range, it becomes easy to suppress deterioration of insulation properties due to heating while enhancing thermal conductivity and adhesion to the metal plate. From such a viewpoint, the above ratio is preferably 0.005 or more, more preferably 0.1 or more, still more preferably 0.2 or more, preferably 3.5 or less, more preferably 3 or less, and further preferably It is preferably 2.5 or less.

Moreover, the content of the inorganic filler in the resin layer containing the inorganic filler (the content of the total inorganic filler) is, for example, 50% by volume or more and 90% by volume or less from the viewpoint of heat dissipation and adhesion to the metal plate. The content of the inorganic filler in the resin layer containing the inorganic filler is preferably 55% by volume or more, more preferably 60% by volume or more, and preferably 90% by volume or less, more preferably 80% by volume or less. is.

(binder resin)
Although the type of binder resin is not particularly limited, the binder resin preferably contains a thermosetting resin, and more preferably contains a thermosetting resin and a curing agent.
When the resin layer contains a thermosetting resin, the thermosetting resin usually exists as a cured resin in the final product form, but may be partly uncured.

Thermosetting resins are not particularly limited, but amino resins such as urea resins and melamine resins, phenol resins, thermosetting urethane resins, epoxy resins, phenoxy resins, thermosetting polyimide resins and aminoalkyd resins, benzoxazine resins, and the like. is mentioned. The thermosetting resin used for the insulating resin sheet may be used singly or in combination of two or more. Among the above-mentioned thermosetting resins, epoxy resins are preferable.

Epoxy resins include, for example, compounds containing two or more epoxy groups in the molecule. The epoxy resin has a weight average molecular weight of less than 5,000, for example.
Specific examples of epoxy resins include styrene skeleton-containing epoxy resins, resorcinol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, phenol novolac-type epoxy resins, biphenol-type epoxy resins, Phenoxy type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, phenylene ether type epoxy resin, fluorene type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, Examples include epoxy resins having an adamantane skeleton, epoxy resins having a tricyclodecane skeleton, epoxy resins having a triazine nucleus in their skeleton, and glycidylamine type epoxy resins.

Moreover, although the epoxy equivalent of the epoxy resin is not particularly limited, it is, for example, 70 g/eq or more and 500 g/eq or less. The epoxy equivalent of the epoxy resin is preferably 80 g/eq or more, and preferably 400 g/eq or less, more preferably 350 g/eq or less. In addition, an epoxy equivalent can be measured according to the method prescribed|regulated to JISK7236, for example.
The epoxy resins described above may be used singly or in combination of two or more.

The content of the binder resin in the resin layer is not particularly limited, but is preferably 10% by volume or more, more preferably 15% by volume or more, and preferably 50% by volume or less, more preferably 40% by volume or less. be. When the content of the binder resin is at least these lower limit values, the inorganic filler such as boron nitride particles can be sufficiently bound after curing to obtain a sheet having a desired shape. When the content of the binder resin is not more than these upper limits, a certain amount or more of inorganic filler such as boron nitride particles can be contained, so that it is possible to improve thermal conductivity while improving insulation. can.

(curing agent)
It is preferable that the above thermosetting resin is cured with a curing agent to bind the inorganic filler.
Examples of curing agents include phenol compounds (phenol heat curing agents), amine compounds (amine heat curing agents), imidazole compounds, acid anhydrides, and the like. Curing agents may be used singly or in combination of two or more.

Examples of phenol compounds include novolac-type phenol, biphenol-type phenol, naphthalene-type phenol, dicyclopentadiene-type phenol, aralkyl-type phenol, and dicyclopentadiene-type phenol.
Amine compounds include dicyandiamide, diaminodiphenylmethane, diaminodiphenylsulfone, and the like.

Examples of imidazole compounds include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2 -methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecyl imidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'- Methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-undecylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6 -[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s- triazine isocyanurate, 2-phenylimidazole isocyanurate, 2-methylimidazole isocyanurate, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-dihydroxymethylimidazole, etc. is mentioned.

Acid anhydrides include styrene/maleic anhydride copolymer, benzophenonetetracarboxylic anhydride, pyromellitic anhydride, trimellitic anhydride, 4,4′-oxydiphthalic anhydride, phenylethynylphthalic anhydride, glycerol. Bis(anhydrotrimellitate) monoacetate, ethylene glycol bis(anhydrotrimellitate), methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride and the like.

The content of the curing agent in the resin layer containing the curing agent is not particularly limited, but is preferably 0.1% by volume or more, more preferably 0.2% by volume or more, and still more preferably 0.5% by volume. and preferably 15% by volume or less, more preferably 12% by volume or less, and even more preferably 10% by volume or less.

(Curing accelerator)
The binder resin may further use a curing accelerator. By using a curing accelerator, the curing speed is increased, the thermosetting resin can be cured quickly, and the crosslinked structure in the resin layer can be made uniform. Also, the number of unreacted functional groups is reduced, resulting in a higher crosslink density.
The curing accelerator is not particularly limited, and conventionally known curing accelerators can be used. Specifically, anionic curing accelerators such as imidazole compounds, cationic curing accelerators such as amine compounds, curing accelerators other than anionic and cationic curing accelerators such as phosphorus compounds and organometallic compounds, and peroxides and radical curing accelerators such as substances. The content of the curing accelerator in the resin layer containing the curing accelerator is, for example, 0.1% by volume or more and 8% by volume or less, preferably 0.3% by volume or more and 5% by volume or less.
A hardening accelerator may be used individually by 1 type, and 2 or more types may be used together.

(Other additives)
In addition to the above components, the resin layer contains a dispersant, a coupling agent such as a silane coupling agent, a flame retardant, an antioxidant, an ion scavenger, a tackifier, a plasticizer, a thixotropic agent, and a colorant. It may contain other additives such as

<Metal base plate>
Since the metal base plate functions as a heat conductor, the heat conductivity thereof is preferably 10 W/m·K or more. Metal base plates include metals such as aluminum, copper, gold, and silver, and graphite sheets. From the viewpoint of more effectively increasing thermal conductivity, aluminum, copper, or gold is preferred, aluminum or copper is more preferred, and copper is even more preferred. A metal base plate may be used as a heat sink or the like.
The thickness of the metal base plate is preferably 0.1 mm or more and 5 mm or less, more preferably 0.5 mm or more and 3 mm or less.

The laminate of the present invention may be composed of only the metal base plate, the second resin layer, the heat-conducting intermediate layer, the first resin layer, and the metal plate described above. Other layers may be included. Other layers are, for example, between the metal base plate and the second resin layer, between the second resin layer and the heat-conducting intermediate layer, between the heat-conducting intermediate layer and the first resin layer, and the first resin layer. and a metal plate. Other layers include, for example, a second thermally conductive intermediate layer and a third resin layer. The material and thickness of the second thermally conductive intermediate layer may be appropriately selected from among the thermally conductive intermediate layers described above. Also, the material and thickness of the third resin layer may be appropriately selected from among the resin layers described above.
From the standpoint of ease of manufacture, the laminate of the present invention, as shown in FIG. preferably configured.

[Semiconductor device]
The present invention also provides a semiconductor device having the laminate described above. Specifically, as shown in FIG. 3, the semiconductor device 15 is a laminate having a metal base plate 11, a second resin layer 10b, a heat-conducting intermediate layer 18, a first resin layer 10a, and a metal plate 12. 13 and a semiconductor element 14 provided on the metal plate 12 of the laminate 13 . The metal plate 12 is preferably patterned by etching or the like to have a circuit pattern. Moreover, the semiconductor element 14 is preferably provided on a metal plate having a circuit pattern.

Although two semiconductor elements 14 are shown in FIG. 3, the number of semiconductor elements 14 is not limited, and may be any number as long as it is one or more. Further, other electronic components (not shown) such as transistors may be mounted on the metal plate 12 in addition to the semiconductor element 14 . Each semiconductor element 14 is connected to the metal plate 12 via a connection conductive portion 16 formed on the metal plate 12 . The connection conductive portion 16 is preferably made of solder. A sealing resin 19 is provided on the surface of the laminate 13 on the metal plate 12 side. At least the semiconductor element 14 is sealed with the sealing resin 19 , and the metal plate 12 is preferably sealed together with the semiconductor element 14 with the sealing resin 19 as necessary.
The semiconductor elements 14 are not particularly limited, but at least one is preferably a power element (that is, a power semiconductor element), so that the semiconductor device 15 is preferably a power module. Power modules are used, for example, in inverters and the like.
Moreover, the power module is used in industrial equipment such as elevators and uninterruptible power supplies (UPS), but the application is not particularly limited.

A lead 20 is connected to the metal plate 12 . The lead 20 extends outside, for example, from the sealing resin 19 and connects the metal plate 12 to an external device or the like. Also, a wire 17 may be connected to the semiconductor element 14 . The wires 17 may connect the semiconductor element 14 to another semiconductor element 14, the metal plate 12, the leads 20, etc., as shown in FIG.
When the semiconductor element 14 is driven by being supplied with power through the leads 20 or the like, it generates heat. heat is radiated from The metal base plate 11 may be connected to a heat sink made up of radiation fins or the like, if necessary.

The semiconductor device 15 is preferably manufactured through a reflow process in its manufacturing process. Specifically, in the manufacturing method of the semiconductor device 15, first, the laminate 13 is prepared, the connection conductive portion 16 is formed on the metal plate 12 of the laminate 13 by solder printing or the like, and the connection conductive portion 16 is formed. A semiconductor element 14 is mounted on the . After that, the laminate 13 with the semiconductor element 14 mounted thereon is passed through a reflow furnace and heated inside the reflow furnace, and the semiconductor element 14 is connected onto the metal plate 12 by the connecting conductive portions 16 . Although the temperature in the reflow furnace is not particularly limited, it is, for example, about 200 to 300.degree. In the method of manufacturing the semiconductor device 15, the semiconductor element 14 may be sealed by laminating the sealing resin 19 on the laminate 13 after the reflow process. Also, before sealing with the sealing resin 19, the wires 17, the leads 20, etc. may be appropriately attached.
In the above description, a mode in which the semiconductor element 14 is connected to the metal plate 12 by the reflow process is shown, but the present invention is not limited to this mode. substrate (not shown).

(Method for manufacturing resin layer and laminate)
The first resin layer and the second resin layer are preferably formed from a resin composition containing components constituting each resin layer. For example, when forming a resin layer containing the inorganic filler and the binder resin described above, it can be formed by molding a curable resin composition containing the inorganic filler and the binder resin into a sheet. The curable resin composition may contain other additives as described above.
The curable resin composition may be formed into a sheet by coating or laminating it on a support such as a release sheet, or may be coated or laminated on a metal base plate, a thermal conductive intermediate layer, or a metal plate. For example, it may be formed into a sheet shape. Here, the term "sheet-like" refers to a thin, flat one whose thickness is small relative to its length and width, and which is formed in the form of a film or layer on another member such as a support or a metal base plate. are also included in the sheet concept.

A curable resin composition formed into a sheet by coating, lamination or the like can be partially or completely cured by press molding or the like under heat and pressure to form a resin layer.

When manufacturing a laminate, a first resin layer and a second resin layer are prepared in advance, and a metal base plate, a second resin layer, a heat-conducting intermediate layer, a first resin layer, and a metal plate are prepared. are laminated in this order, and heat and pressure are applied by press molding to bond the respective interfaces, thereby producing a laminate.
Alternatively, the metal base plate, the second curable resin composition for forming the second resin layer, the heat conductive intermediate layer, the first curable resin composition for forming the first resin layer, the metal The laminate may be manufactured by arranging the plates in this order and applying heat and pressure by press molding to cure the curable resin composition. In this case, the first curable resin composition for forming the first resin layer may be applied to either the metal plate or the heat-conducting intermediate layer. Also, the second curable resin composition for forming the second resin layer may be applied and arranged on either the metal base plate or the heat-conducting intermediate layer.

Furthermore, the laminate of the present invention may be obtained by the following method.
First, a first curable resin composition is applied onto a release sheet (for example, a release PET sheet) and dried to obtain a first coated resin sheet. Also, a second coated resin sheet is obtained in the same manner using the second curable resin composition.
Next, the metal base plate, the second coated resin sheet, the heat-conducting intermediate layer, the first coated resin sheet, and the metal plate are laminated in this order, and then heated and pressed by press molding to form the laminate of the present invention. can get. By the press molding, the first coated resin sheet is cured to form the first resin layer, and the second coated resin sheet is cured to form the second resin layer.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these.

In addition, the measuring method and evaluation method of each physical property are as follows.
[Thermal conductivity of resin layer]
After cutting the sheet-shaped first resin layer and the second resin layer prepared in each example and comparative example into 1 cm squares, carbon black was sprayed on both sides of the measurement sample, and the measuring device "Nanoflash" ( Thermal conductivity was measured by a laser flash method using NETZSCH, model number: LFA447).

[Thermal resistance value of laminate]
A rectifying diode (TO-220 manufactured by Wolfspeed) was soldered as a heat generating chip to the metal plate side (the side on which the pattern was formed) of the laminates prepared in each of Examples and Comparative Examples. Next, a current cable was connected to the heating chip to obtain a measurement sample.
On a cooling plate maintained at 25° C., a gel sheet (COH-400LVC, thickness 1 mm, manufactured by Taica) having the same size as the measurement sample was placed, and the measurement sample was laminated thereon. The heat-generating chip of the measurement sample was heated at a calorific value of 20 W for 100 seconds, and the temperature of the chip was adjusted to 80.degree. After that, the heat generation was stopped and the sample was allowed to cool for 100 seconds, and the heat resistance value was calculated from the obtained cooling curve of time and temperature. The thermal resistance value was the average value of the thermal resistance values measured using five measurement samples.
Based on the thermal resistance value measured as described above, evaluation was made according to the following criteria.
(Evaluation criteria)
◎ Less than 2.60 K/W ○ 2.60 K/W or more and less than 2.70 K/W × 2.70 K/W or more

[Pattern workability]
A mask for forming a pattern with an interval of 10 mm is placed on the surface of the metal plate of the laminate of each example and comparative example, and an etching solution (an aqueous solution of ferric chloride with 0.5% by volume of hydrochloric acid is mixed. The metal layer was etched with a solution obtained by etching the metal layer, and the pattern workability was evaluated based on the width of the taper formed at that time.
FIG. 4 schematically shows a method for evaluating pattern processability. When the metal plate 12 is etched, it is ideal that the metal plate 12 is etched from the surface to the inside in parallel with the thickness direction, but as shown in FIG. It may have a tapered shape that slopes from the surface to the inside. Pattern workability was evaluated using the horizontal distance d when the etched portion T was viewed from above as the taper width. Ten etched portions T were observed, and the taper width was obtained as an average value and evaluated according to the following criteria. A shorter taper width means better pattern workability.
(Evaluation criteria)
〇 Taper width less than 0.7mm x Taper width more than 0.7mm

Raw materials and members used in Examples and Comparative Examples are as follows.
(Thermosetting resin)
Biphenyl-type epoxy resin: "YX-4000", phenoxy-type epoxy resin manufactured by Mitsubishi Chemical Corporation: "jER-1256", manufactured by Mitsubishi Chemical Corporation (curing agent)
Phenolic compound: "MEH-7851-S", manufactured by Showa Kasei Co., Ltd. (curing accelerator)
Imidazole compound: "2MAOK", manufactured by Shikoku Kasei Co., Ltd. (dispersant)
Dispersant: "ED151", manufactured by Kusumoto Kasei Co., Ltd.

(boron nitride aggregate particles)
・ “HP-40” manufactured by Mizushima Ferroalloy Co., Ltd., average particle size of aggregated particles 40 μm

(alumina)
・"AA-05" manufactured by Sumitomo Chemical Co., Ltd., average particle size 0.5 μm
・"AA-18" manufactured by Sumitomo Chemical Co., Ltd., average particle size 18 μm

(magnesium oxide)
・"RF-10C-45μm" manufactured by Ube Material

(aluminum nitride)
・"ANF-A-05" manufactured by MARUWA

(diamond)
・"FMM0-2" manufactured by Global Diamond Co., Ltd.

(metal plate)
Copper plate with two different thicknesses. Thickness is 0.8mm or 1.5mm

(Heat-conducting intermediate layer)
Copper plate: Thickness direction thermal conductivity 400 W/(m K), thickness: 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 1 mm, 1.5 mm Aluminum nitride plate: Thickness Thermal conductivity in the longitudinal direction 230 W/(m K), thickness 0.7 mm
Silicon nitride plate: thermal conductivity in thickness direction 90 W/(m/K), thickness 0.7 mm
Graphite sheet: Thermal conductivity in thickness direction 15W/(mK), thickness 0.025mm

(metal base plate)
Copper plate, thickness 2mm

[Example 1]
A curable resin composition D was obtained by mixing the thermosetting resin, inorganic filler, curing agent, curing accelerator, and dispersant shown in Table 1 in the amounts shown in Table 1. The curable resin composition D was applied onto a release PET sheet and dried in an oven at 50° C. for 10 minutes to form a first coated resin sheet. A second coated resin sheet was also formed in the same manner.
Next, the metal base plate (copper plate), the second coated resin sheet, the heat-conducting intermediate layer (copper plate), the first coated resin sheet, and the metal plate are laminated in this order. After pressing for 30 minutes, it was pressed at 195° C. for 30 minutes to obtain a laminate. The laminate is a laminate in which a metal base plate, a second resin layer, a heat-conducting intermediate layer, a first resin layer, and a metal plate are laminated in this order, and the thickness of each member constituting the laminate is shown in the table. 2. Each evaluation result is shown in Table 2.

[Examples 2 to 13, Examples 15 to 17, Comparative Examples 3 and 4]
Example 1 was repeated except that the type of curable resin composition used, the thicknesses of the first resin layer and the second resin layer, and the type and thickness of the heat-conducting intermediate layer were changed as shown in Tables 2 and 3. to obtain a laminate. Each evaluation result is shown in Tables 2 and 3.

[Example 14]
A curable resin composition D was obtained by mixing the thermosetting resin, inorganic filler, curing agent, curing accelerator, and dispersant shown in Table 1 in the amounts shown in Table 1. The curable resin composition D was applied onto a release PET sheet and dried in an oven at 50° C. for 10 minutes to form a first coated resin sheet. A second coated resin sheet and a third coated resin sheet were formed in the same manner.
Then, the metal base plate (copper plate), the third coating sheet, the thermally conductive intermediate layer (copper plate), the second coated resin sheet, the thermally conductive intermediate layer (copper plate), the first coated resin sheet, the metal The plates were laminated in this order, pressed at 75° C. for 50 minutes at a pressure of 15 MPa, and then pressed at 195° C. for 30 minutes to obtain a laminate. The laminate comprises a metal base plate, a third resin layer, a second heat-conducting intermediate layer, a second resin layer, a first heat-conducting intermediate layer, a first resin layer, and a metal plate, which are laminated in this order. Table 2 shows the thickness of each member constituting the laminate. Each evaluation result is shown in Table 2.

[Comparative Example 1]
A curable resin composition D was obtained by mixing the thermosetting resin, inorganic filler, curing agent, curing accelerator, and dispersant shown in Table 1 in the amounts shown in Table 1. The curable resin composition D was applied onto a release PET sheet and dried in an oven at 50° C. for 10 minutes to form a first coated resin sheet.
Next, the metal base plate (copper plate), the first coated resin sheet, and the metal plate (copper plate) are laminated in this order, pressed at 145° C. for 30 minutes at a pressure of 5 MPa, and then pressed at 195° C. for 55 minutes. A laminate was obtained. The laminate was a laminate in which a metal base plate, a first resin layer, and a metal plate were laminated in this order, and Table 3 shows the evaluation results.

[Comparative Example 2]
A laminate was obtained in the same manner as in Comparative Example 1, except that the thickness of the metal plate was changed as shown in Table 3. Each evaluation result is shown in Table 3.

From the results of each example, the second resin layer, the heat-conducting intermediate layer, the first resin layer, and the metal plate are provided in this order on the metal base plate, and the metal plate and the heat-conducting intermediate layer have a predetermined thickness. It was found that the laminate of the present invention in the range of has a low heat resistance value and excellent pattern workability.
On the other hand, in the laminates of Comparative Examples 1 and 2, which do not have the heat-conducting intermediate layer, the thermal resistance value increases when the thickness of the metal plate is thin, and the thermal resistance value decreases when the thickness of the metal plate increases. However, pattern workability deteriorated. Further, from the results of Comparative Examples 3 and 4, even when the heat-conducting intermediate layer was included, when the thickness was thinner than the predetermined thickness, the laminate had a high thermal resistance value.

10a First resin layer 10b Second resin layer 10c Third resin layer 11 Metal base plate 12 Metal plate 13 Laminated body 14 Semiconductor element 15 Semiconductor device 16 Connection conductive part 17 Wire 18 Thermal conductive intermediate layer 18a First heat Conductive intermediate layer 18b Second heat conductive intermediate layer 19 Sealing resin 20 Lead

Claims (17)

A metal base plate, a second resin layer, a heat-conducting intermediate layer, a first resin layer, and a metal plate are provided in this order, wherein the metal plate has a thickness of 1.4 mm or less, and the heat-conducting intermediate layer has a thickness of A laminate having a thickness of 0.2 mm or more. The laminate according to claim 1, wherein the ratio of the thickness of said first resin layer to the total thickness of said first resin layer and said second resin layer is 0.05 or more and 0.9 or less. The laminate according to claim 2, wherein the total thickness of the first resin layer and the second resin layer is 0.01 mm or more and 0.3 mm or less. the thermally conductive intermediate layer is a first thermally conductive intermediate layer;
Claims 1 to 1, comprising a metal base plate, a third resin layer, a second heat-conducting intermediate layer, a second resin layer, a first heat-conducting intermediate layer, a first resin layer, and a metal plate in this order. 3. The laminate according to any one of 3 5. The laminate according to claim 4, wherein the total thickness of said first resin layer, said second resin layer and said third resin layer is 0.02 mm or more and 0.5 mm or less. 4. The laminate according to claim 1, wherein at least one of the resin layers included in the laminate is an insulating resin layer. The laminate according to any one of claims 1 to 3, wherein at least one of the resin layers included in the laminate has a thermal conductivity of 3 W/(m·K) or more. The laminate according to any one of claims 1 to 3, wherein at least one of the resin layers included in the laminate contains an inorganic filler and a binder resin. 9. The laminate of Claim 8, wherein the binder resin comprises a thermosetting resin and a curing agent, and the thermosetting resin comprises an epoxy resin. 9. The laminate according to claim 8, wherein said inorganic filler comprises boron nitride particles. 9. The laminate according to claim 8, wherein the content of the inorganic filler in the resin layer containing the inorganic filler is 50% by volume or more and 90% by volume or less. The laminate according to claim 8, wherein the inorganic filler contains an inorganic filler other than boron nitride particles. 13. The laminate according to claim 12, wherein the inorganic filler other than the boron nitride particles is at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide. The laminate according to any one of claims 1 to 3, wherein the heat conductive intermediate layer has a heat conductivity of 100 W/(m·K) or more. 4. The laminate according to any one of claims 1 to 3, wherein the heat-conducting intermediate layer contains at least one selected from the group consisting of copper, aluminum nitride, and silicon nitride. The laminate according to any one of claims 1 to 3, wherein the metal plate is a metal plate having a circuit pattern. 17. A semiconductor device comprising: the laminate of claim 16; and a semiconductor element provided on a metal plate having a circuit pattern of the laminate.