Laminate, heat dissipation substrate, and method for manufacturing laminate

Abstract

To provide a laminate, a heat dissipation substrate, and a method for manufacturing the laminate that has excellent insulation properties while also being thin and having excellent thermal conductivity.SOLUTION: A laminate 1 has a metal substrate 2 and an inorganic insulating layer 3 in order in the direction of thickness. The inorganic insulating layer 3 has a first layer 31 and a second layer 32, each of which has a different dielectric breakdown voltage and thermal conductivity, in that order. The thickness of the inorganic insulating layer 3 is 10 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminate, a heat dissipation substrate, and a method for manufacturing the laminate. [Background technology]

[0002] A laminate including a copper substrate, a titanium nitride layer, and aluminum nitride in that order in the thickness direction is known (see, for example, Patent Document 1 below). In the laminate described in Patent Document 1, the total thickness of the titanium nitride layer and aluminum nitride is 34 μm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-058706 A Summary of the Invention [Problem to be solved by the invention]

[0004] The laminate is required to be thin and have excellent thermal conductivity, but the laminate described in Patent Document 1 may not satisfy these requirements.

[0005] The laminate is also required to have excellent insulating properties.

[0006] The present invention provides a laminate that is thin and has excellent thermal conductivity while having excellent insulating properties, a heat dissipation substrate, and a method for manufacturing the laminate. [Means for solving the problem]

[0007] The present invention (1) includes a laminate comprising a metal substrate and an inorganic insulating layer in order in a thickness direction, the inorganic insulating layer comprising, in order, a first layer and a second layer each having a different dielectric strength voltage and thermal conductivity, the inorganic insulating layer having a thickness of 10 μm or less.

[0008] The present invention (2) includes the laminate according to (1), in which the material of the metal substrate is copper or a copper alloy.

[0009] The present invention (3) includes the laminate according to (1) or (2), in which the material of the inorganic insulating layer is at least one selected from the group consisting of oxides, nitrides, and oxynitrides.

[0010] The present invention (4) includes the laminate according to any one of (1) to (3), wherein the material of the inorganic insulating layer contains at least one selected from the group consisting of aluminum, magnesium, zinc, silicon, yttrium, and titanium.

[0011] The present invention (5) includes the laminate according to any one of (1) to (4), wherein the first layer has a higher dielectric strength voltage than the second layer, and the second layer has a higher thermal conductivity than the first layer.

[0012] The present invention (6) includes the laminate according to any one of (1) to (4), wherein the second layer has a higher dielectric strength voltage than the first layer, and the first layer has a higher thermal conductivity than the second layer.

[0013] The present invention (7) includes the laminate according to any one of (1) to (6), wherein the metal substrate includes one surface and the other surface in the thickness direction and a side surface connecting a peripheral edge of the one surface and a peripheral edge of the other surface, and the inorganic insulating layer is disposed on the one surface and the side surface of the metal substrate.

[0014] The present invention (8) includes a heat dissipation substrate comprising the laminate according to any one of (1) to (7).

[0015] The present invention (9) is a method for producing the laminate according to any one of (1) to (7), and includes a method for producing a laminate, in which an inorganic insulating layer is formed on one surface of a metal substrate in a thickness direction by using a vacuum film formation method. Effect of the Invention

[0016] The laminate produced by the production method of the present invention and a heat dissipation substrate including the laminate have excellent insulating properties, are thin, and have excellent thermal conductivity. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of a laminate of the present invention. [Diagram 2] FIG. 2 is a plan view of the laminate shown in FIG. [Diagram 3] FIG. 11 is a cross-sectional view of a laminate of a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1. One embodiment of the laminate An embodiment of the laminate of the present invention will be described with reference to Fig. 1 and Fig. 2. The laminate 1 has a thickness. The laminate 1 has a plate shape. In this embodiment, the laminate 1 has a rectangular plate shape. The laminate 1 extends in a planar direction. The planar direction is perpendicular to the thickness direction. The laminate 1 includes a metal substrate 2 and an inorganic insulating layer 3.

[0019] 1.1 Metal substrate 2 The metal substrate 2 has a plate shape. In this embodiment, the metal substrate 2 has a rectangular plate shape. The metal substrate 2 includes one surface 21 and another surface 22 in the thickness direction, and a side surface 23 connecting the peripheral edge of the one surface 21 and the peripheral edge of the other surface 22.

[0020] Each of the first surface 21 and the second surface 22 has a flat shape. The first surface 21 and the second surface 22 are parallel to each other. The first surface 21 and the second surface 22 are perpendicular to the thickness direction.

[0021] The side surface 23 is aligned along the thickness direction. In this embodiment, the side surface 23 is perpendicular to the one surface 21 and the other surface 22.

[0022] There is no limitation on the material of the metal substrate 2. The material of the metal substrate 2 is preferably copper or a copper alloy.

[0023] The metal substrate 2 has a thickness of, for example, 30 μm or more, preferably 50 μm or more, and for example, 1000 μm or less, preferably 500 μm or less.

[0024] 1.2 Inorganic insulating layer 3 The inorganic insulating layer 3 is disposed on one surface 21 of the metal substrate 2. The inorganic insulating layer 3 contacts the entire one surface 21 of the metal substrate 2. The inorganic insulating layer 3 follows the shape of the one surface 21. In this embodiment, the inorganic insulating layer 3 has a shape extending in the planar direction. The inorganic insulating layer 3 includes a first layer 31 and a second layer 32 in that order in the thickness direction.

[0025] 1.2.1 First layer31 The first layer 31 is an inner layer in the inorganic insulating layer 3. Specifically, the first layer 31 is disposed on one surface 21 of the metal substrate 2. The first layer 31 contacts the entire one surface 21 of the metal substrate 2.

[0026] 1.2.2 Second layer32 The second layer 32 is an outer layer of the inorganic insulating layer 3. The second layer 32 is disposed on the opposite side of the metal substrate 2 to the first layer 31. The second layer 32 contacts the entire one surface of the first layer 31 in the thickness direction. The second layer 32 forms one surface (exposed surface) of the laminate 1 in the thickness direction.

[0027] 1.2.3 Physical properties of the first layer 31 and the second layer 1.2.3.1 Dielectric strength The dielectric strength voltage of the first layer 31 and the dielectric strength voltage of the second layer 32 are different.

[0028] In this embodiment, the dielectric strength of the first layer 31 is higher than the dielectric strength of the second layer 32. Note that the "dielectric strength" is a concept that includes the "dielectric breakdown field strength" evaluated in the examples below. The dielectric breakdown field strength is obtained from literature values ​​based on the materials (described below) of the first layer 31 and the second layer 32. The dielectric breakdown field strength can also be actually measured.

[0029] The first layer 31 has a dielectric breakdown field strength of, for example, more than 2 MV / cm, preferably 3 MV / cm or more, and for example, 100 MV / cm or less, preferably 20 MV / cm or less.

[0030] The second layer 32 has a breakdown field strength of, for example, 2 MV / cm or less, preferably 1 MV / cm or less, and for example, 0.1 MV / cm or more, preferably 0.2 MV / cm or more.

[0031] In this embodiment, the ratio of the dielectric strength voltage of the first layer 31 to the dielectric strength voltage of the second layer 32 is, for example, 1.25 or more, or preferably 1.5 or more, and for example, 25 or less, or preferably 15 or less.

[0032] 1.2.3.2 Thermal Conductivity The thermal conductivity of the first layer 31 and the thermal conductivity of the second layer 32 are different.

[0033] In this embodiment, the thermal conductivity of the second layer 32 is higher than that of the first layer 31. The thermal conductivity is obtained from literature values ​​based on the materials (described below) of the first layer 31 and the second layer 32. The thermal conductivity can also be actually measured.

[0034] The thermal conductivity of the first layer 31 is, for example, 5 W / K·m or less, or preferably 3 W / K·m or less, and for example, 0.1 W / K·m or more, or preferably 0.5 W / K·m or more.

[0035] The thermal conductivity of the second layer 32 is, for example, 10 W / K·m or more, preferably 15 W / K·m or more, and for example, 1000 W / K·m or less, preferably 100 W / K·m or less.

[0036] In this embodiment, the ratio of the thermal conductivity of the second layer 32 to the thermal conductivity of the first layer 31 is, for example, 2 or more, preferably 10 or more, more preferably 15 or more, and for example, 150 or less, preferably 100 or less, more preferably 50 or less.

[0037] 1.2.3.3 Crystallinity The crystallinity of each of the first layer 31 and the second layer 32 is not limited. In this embodiment, the first layer 31 is preferably amorphous. If the first layer 31 is amorphous, the dielectric strength voltage of the first layer 31 can be made higher than the dielectric strength voltage of the second layer 32.

[0038] In this embodiment, the second layer 32 is preferably crystalline. If the second layer 32 is crystalline, the thermal conductivity of the second layer 32 can be made higher than the thermal conductivity of the second layer 32.

[0039] The crystallinity of each of the first layer 31 and the second layer 32 is <1> Grazing incidence X-ray diffraction (GIXD), <2> Out-of-plane crystal analysis by X-ray diffraction (XRD), or <3> This is determined by observing the crystal grains using a transmission electron microscope (TEM).

[0040] 1.2.3.4 Thickness The thickness of each of the first layer 31 and the second layer 32 is not limited. The thickness of the first layer 31 and the second layer 32 may be the same or different. The thickness of each of the first layer 31 and the second layer 32 is, for example, 5 nm or more, preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more. When the thickness of each of the first layer 31 and the second layer 32 is equal to or greater than the above-mentioned lower limit, the laminate 1 has excellent insulating properties.

[0041] The thickness of each of the first layer 31 and the second layer 32 is, for example, 5 μm or less, preferably 1 μm or less, more preferably 500 nm or less, and even more preferably 250 nm or less. When the thickness of each of the first layer 31 and the second layer 32 is equal to or less than the above-mentioned upper limit, the laminate 1 is thin and has excellent thermal conductivity.

[0042] The inorganic insulating layer 3 has a thickness of 10 μm or less. The thickness of the inorganic insulating layer 3 is the total thickness of the first layer 31 and the second layer 32.

[0043] On the other hand, if the thickness of the inorganic insulating layer 3 exceeds 10 μm, the inorganic insulating layer 3 becomes too thick, the laminate 1 becomes large, and furthermore, the thermal conductivity of the inorganic insulating layer 3 becomes poor.

[0044] On the other hand, the thickness of the inorganic insulating layer 3 is preferably 2 μm or less, more preferably 1 μm or less, and further preferably 500 nm or less.

[0045] The inorganic insulating layer 3 has a thickness of, for example, 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more, and even more preferably 40 nm or more. When the inorganic insulating layer 3 has a thickness equal to or more than the above-mentioned lower limit, the laminate 1 has excellent insulating properties.

[0046] The ratio of the thickness of the inorganic insulating layer 3 to the thickness of the metal substrate 2 is, for example, 0.00001 or more, preferably 0.0001 or more, and for example, 0.35 or less, preferably 0.1 or less.

[0047] 1.2.3.5 Materials Examples of the material of the inorganic insulating layer 3 include inorganic substances. Examples of the inorganic substances include oxides, nitrides, and oxynitrides. The material of the inorganic insulating layer 3 contains at least one selected from the group consisting of aluminum, magnesium, zinc, silicon, yttrium, and titanium. Preferable examples of the material include silicon, aluminum, and titanium. The above-mentioned materials can be used alone or in combination.

[0048] The oxide may be, for example, aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), zinc oxide (ZnO), silicon oxide (SiO 2 ), yttrium oxide (Y 2 O 3 ) are mentioned.

[0049] Nitrides include, for example, silicon nitride and aluminum nitride.

[0050] Examples of oxynitrides include silicon oxynitride and aluminum oxynitride.

[0051] As the inorganic substance, preferably, an oxide is used.

[0052] The materials of the first layer 31 and the second layer 32 are appropriately selected from the above-mentioned materials so as to satisfy the above-mentioned dielectric strength voltage and thermal conductivity. In this embodiment, the first layer 31 is preferably made of an oxide. The second layer 32 is preferably made of an oxide or a nitride.

[0053] 1.3 Manufacturing method of the laminate 1 A method for manufacturing the laminate 1 will be described. To manufacture the laminate 1, first, a metal substrate 2 is prepared, and then a first layer 31 is formed on one surface 21 of the metal substrate 2 by using a vacuum film-forming method. Examples of the vacuum film-forming method include a vapor deposition method, a sputtering method, and an ion plating method. A preferred example of the vacuum film-forming method is a sputtering method.

[0054] Thereafter, the second layer 32 is formed on one surface (outer surface) by vacuum deposition. The deposition conditions for the second layer 32 may be different from the deposition conditions for the first layer 31, or may be the same.

[0055] 1.4 Uses of Laminate 1 The use of this laminate 1 is not limited. Preferably, the laminate 1 is provided in a heat dissipation substrate 10. That is, the heat dissipation substrate 10 includes the laminate 1 described above. The heat dissipation substrate 10 may further include an electrode 4 (virtual line) arranged on one surface of the laminate 1 in the thickness direction. The electrode 4 has a pattern. The electrode 4 is arranged on a part of one surface of the inorganic insulating layer 3 in the thickness direction. The electrode 4 is made of a conductor. Examples of the conductor include copper and titanium. The electrode 4 is a single layer or multiple layers.

[0056] 2. Effects of one embodiment In this laminate 1, the inorganic insulating layer 3 includes a first layer 31 and a second layer 32 that have different dielectric strength voltages and thermal conductivities. This improves the insulating properties and thermal conductivity of the laminate 1. Furthermore, since the thickness of the inorganic insulating layer 3 is 10 μm or less, the laminate 1 is thin and has even better thermal conductivity. In other words, the laminate 1 has excellent insulating properties, is thin, and has excellent thermal conductivity.

[0057] In the laminate 1 of this embodiment, the first layer 31 has excellent insulating properties, and the second layer 32 has excellent thermal conductivity, so that the two functions of insulating properties and thermal conductivity can be distributed to the two layers. In other words, the first layer 31 is an insulating functional layer, and the second layer 32 is a thermally conductive functional layer. Therefore, the electrode 4 can be reliably insulated by the first layer 31 while efficiently diffusing heat from the electrode 4 disposed on the second layer 32.

[0058] In the method for producing the laminate 1, the inorganic insulating layer 3 is formed by a vacuum film-forming method, so that the inorganic insulating layer 3 can be formed easily.

[0059] 3. Modifications In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, each modification can achieve the same effects as those in the above-described embodiment, unless otherwise specified. Furthermore, the embodiment and the modifications can be appropriately combined.

[0060] 3.1 First modified example In the first modified example, the dielectric strength voltage of the first layer 31 is lower than the dielectric strength voltage of the second layer 32. In other words, the dielectric strength voltage of the second layer 32 is higher than the dielectric strength voltage of the first layer 31. In the first modified example, the ratio of the dielectric strength voltage of the second layer 32 to the dielectric strength voltage of the first layer 31 is, for example, 1.25 or more, preferably 1.5 or more, and for example, 25 or less, preferably 15 or less.

[0061] The dielectric breakdown field strength of the first layer 31 is, for example, less than 6 MV / cm, preferably 5 MV / cm or less, and is, for example, 0.1 MV / cm or more, preferably 1 MV / cm or more.

[0062] The second layer 32 has a breakdown field strength of, for example, 6 MV / cm or more, preferably 8 MV / cm or more, and for example, 100 MV / cm or less, preferably 20 MV / cm or less.

[0063] In the first modified example, the thermal conductivity of the second layer 32 is lower than that of the first layer 31. In other words, the thermal conductivity of the first layer 31 is higher than that of the second layer 32. The ratio of the thermal conductivity of the first layer 31 to the thermal conductivity of the second layer 32 is, for example, 2 or more, preferably 10 or more, more preferably 15 or more, and is, for example, 150 or less, preferably 100 or less, more preferably 50 or less.

[0064] The thermal conductivity of the first layer 31 in the first modified example is, for example, 10 W / K·m or more, preferably 15 W / K·m or more, and for example, 1000 W / K·m or less, preferably 100 W / K·m or less.

[0065] The thermal conductivity of the second layer 32 in the first modified example is, for example, 5 W / K·m or less, or preferably 3 W / K·m or less, and for example, 0.1 W / K·m or more, or preferably 0.5 W / K·m or more.

[0066] 3.1.1 Effects of the First Modification In the first modified example, the first layer 31 is a heat conduction functional layer, and the second layer 32 is an insulating functional layer. Therefore, the electrode 4 arranged on the second layer 32 can be reliably insulated by the second layer 32, while the heat of the electrode 4 can be diffused by the first layer 31.

[0067] 3.2 Second variant In the second modification, the dielectric strength voltage of the first layer 31 is higher than the dielectric strength voltage of the second layer 32, and the thermal conductivity of the first layer 31 is higher than the thermal conductivity of the second layer 32. In other words, the first layer 31 is an insulating and thermally conductive functional layer.

[0068] 3.3 Third variant In the third modification, the dielectric strength voltage of the first layer 31 is lower than the dielectric strength voltage of the second layer 32, and the thermal conductivity of the first layer 31 is lower than the thermal conductivity of the second layer 32. In other words, the second layer 32 is an insulating and thermally conductive functional layer.

[0069] Of the first embodiment and the first to third modified examples, the first embodiment and the first modified example are preferred.

[0070] 3.4 Fourth variant As shown in FIG. 3, in the laminate 1 of the fourth modified example, the inorganic insulating layer 3 is disposed on one surface 21 and side surface 23 of the metal substrate 2. The inorganic insulating layer 3 continuously covers the one surface 21 and side surface 23. The inorganic insulating layer 3 follows the shapes of the one surface 21 and side surface 23. The inorganic insulating layer 3 disposed on the side surface 23 has a shape extending in the thickness direction. The inorganic insulating layer 3 disposed on the side surface 23 has the same physical properties as the inorganic insulating layer 3 disposed on the one surface 21.

[0071] In the fourth modified example, the first layer 31 is disposed on one surface 21 and the side surface 23 of the metal substrate 2. The second layer 32 is disposed on one surface (outer surface) of the first layer 31.

[0072] 3.4.1 Effects of the Fourth Modification In the laminate 1 of the fourth modification, the inorganic insulating layer 3 is also formed on the side surface 23 of the metal substrate 2, so that the laminate 1 has excellent insulation properties and thermal conductivity on the side surfaces.

[0073] 3.5 Fifth Variation As shown by the phantom line in Fig. 1, the laminate 1 may further include an adhesion layer 5. The adhesion layer 5 is disposed between one surface 21 of the metal substrate 2 and the inorganic insulating layer 3. An example of the adhesion layer 5 is a chromium layer. The thickness of the adhesion layer 5 is, for example, 10 nm or more and 100 nm or less. The adhesion layer 5 is formed, for example, by a vacuum film formation method. EXAMPLES

[0074] The present invention will be described in more detail below with reference to examples. Note that the present invention is not limited to the examples. In addition, the specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (a numerical value defined as "not more than" or "less than") or lower limit (a numerical value defined as "not less than" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention".

[0075] <Example 1> A metal substrate 2 was prepared. The metal substrate 2 had a thickness of 150 μm and was made of copper.

[0076] Next, an adhesion layer 5 made of chromium and having a thickness of 20 nm was formed by vacuum film formation under the following film formation conditions.

[0077] Vacuum deposition method: DC magnetron sputtering method Sputtering gas: Ar Sputtering pressure: 0.2Pa Output: 80W Sputtering temperature: 25℃

[0078] Next, silica oxide (SiO 2 ) and a thickness of 25 nm. The film formation conditions were as follows.

[0079] Vacuum deposition method: RF magnetron sputtering method Sputtering gas: Ar / O 2 Gas mixtures Sputtering pressure: 0.2Pa Output: 100W Sputtering temperature: 25℃

[0080] Then, magnesium oxide (MgO 2 ) and a thickness of 25 nm. The film formation conditions were as follows.

[0081] Vacuum deposition method: RF magnetron sputtering method Sputtering gas: Ar / O 2 Gas mixtures Sputtering pressure: 0.2Pa Output: 100W Sputtering temperature: 25℃

[0082] In this way, the laminate 1 was produced.

[0083] <Example 2 to Example 4> A laminate 1 was produced in the same manner as in Example 1. However, the material of the inorganic insulating layer 3 was changed as shown in Table 1.

[0084] <Comparative Example 1 to Comparative Example 2> A laminate 1 was produced in the same manner as in Example 1. However, the first layer 31 was not formed, and the thickness was changed as shown in Table 1.

[0085] <Comparative Example 3> A laminate 1 was produced in the same manner as in Example 1. However, the second layer 32 was not formed, and the thickness was changed as shown in Table 1.

[0086] <Evaluation> 1. Crystallinity Grazing incidence X-ray diffraction measurements (GIXD) were carried out using an X-ray diffractometer under the following measurement conditions. The crystallinity of the first layer 31 and the second layer 32 was evaluated. Note that the first layer 31 was evaluated for the laminate 1 before the second layer 32 was formed.

[0087] X-ray entrance side: entrance parallel slit, solar slit 5°, vertical limit slit 10 mm, width limit slit 0.1 mm X-ray receiving side: receiving slit 20mm, parallel slit analyzer 0.5° and solar slit 5° X-ray source: Cu Kα radiation (wavelength: 1.5418 Å) with output of 40 kV-50 mA, incidence angle of 0.1°, step width of 0.1°, scan speed of 4° / min

[0088] It was confirmed that the first layer 31 of Example 1, the first layer 31 of Example 2, the first layer of Example 3, the second layer 32 of Example 4, and the inorganic insulating layer 3 of Comparative Example 3 each had no diffraction peaks derived from crystal lattices at an incident angle (2θ) of 20°-35°. In other words, each of the above layers was amorphous. This is shown in Table 1.

[0089] On the other hand, it was confirmed that the second layer 32 of Example 1, the second layer 32 of Example 2, the second layer 32 of Example 3, the first layer 31 of Example 4, the inorganic insulating layer 3 of Comparative Example 1, and the inorganic insulating layer 3 of Comparative Example 2 had diffraction peaks derived from crystal lattices at incident angles (2θ) of 20°-35°. In other words, each of the above layers was crystalline. This is shown in Table 1.

[0090] 2. Breakdown field strength The dielectric breakdown field strengths of the first layer 31 and the second layer 32 in the inorganic insulating layer 3 were obtained from the values ​​given in the literature in Table 2. The dielectric breakdown field strengths are given in Tables 1 and 2.

[0091] 3. Thermal Conductivity The thermal conductivity of each of the first layer 31 and the second layer 32 in the inorganic insulating layer 3 was obtained from the values ​​listed in the literature in Table 2. The thermal conductivities are listed in Tables 1 and 2.

[0092] 4. Insulation of the laminate 1 An electrode 4 was formed on one surface of the laminate 1 of each of Examples 1 to 4 and Comparative Examples 1 to 3 through a metal mask having an opening. The electrode 4 includes a titanium layer having a thickness of 50 nm and a copper layer having a thickness of 100 nm, which are arranged in this order toward one side in the thickness direction. The electrode 4 has a length of 2.5 mm and a width of 2.5 mm.

[0093] The film formation conditions for the electrode 4 are as follows.

[0094] Vacuum deposition method: DC magnetron sputtering method Sputtering gas: Ar Sputtering pressure: 0.2Pa Output: 80W Sputtering temperature: 25℃

[0095] A digital multimeter 6 (phantom line) was connected to the metal substrate 2 and the electrode 4 via a line 7 (phantom line). The resistance in the thickness direction of the laminate 1 was then measured. The insulation was then evaluated according to the following criteria. The results are shown in Table 1.

[0096] ◯: The resistance was more than 2 MΩ and the insulation was good. ×: The resistance was 2 MΩ or less, and the insulation was poor.

[0097] 5. Area-standardized thermal resistance of inorganic insulating layer 3 The thermal resistance was calculated from the cross-sectional area and thermal conductivity of the inorganic insulating layer 3 per unit length. The insulation was evaluated from the area-standardized thermal resistance according to the following criteria. The results are shown in Table 1.

[0098] ○: Area standard thermal resistance is 5×10 -8 KW -1 m -2 The thermal conductivity was good. ×: Area standard thermal resistance is 5×10 -8 KW -1 m -2 As a result, the thermal conductivity was poor.

[0099] [Table 1]

[0100] [Table 2] [Explanation of symbols]

[0101] 1. Laminate 2 Metal Substrate 3. Inorganic insulating layer 10 Heat dissipation board 21 One side 22 Other side 23 Side 31 First layer 32 Second layer

Claims

1. A metal substrate and an inorganic insulating layer are provided in that order in a thickness direction, the inorganic insulating layer includes a first layer and a second layer, each of which has a different dielectric strength voltage and a different thermal conductivity, in that order; The inorganic insulating layer has a thickness of 10 μm or less.

2. The laminate according to claim 1 , wherein the material of the metal substrate is copper or a copper alloy.

3. 3. The laminate according to claim 1, wherein the material of the inorganic insulating layer is at least one selected from the group consisting of oxides, nitrides, and oxynitrides.

4. 4. The laminate according to claim 1, wherein the material of the inorganic insulating layer contains at least one selected from the group consisting of aluminum, magnesium, zinc, silicon, yttrium, and titanium.

5. a dielectric strength voltage of the first layer is higher than a dielectric strength voltage of the second layer; The laminate according to claim 1 , wherein the second layer has a higher thermal conductivity than the first layer.

6. a dielectric strength voltage of the second layer is higher than a dielectric strength voltage of the first layer; The laminate according to claim 1 , wherein the first layer has a higher thermal conductivity than the second layer.

7. the metal substrate includes one surface and another surface in a thickness direction, and a side surface connecting a peripheral edge of the one surface and a peripheral edge of the other surface; The laminate according to claim 1 , wherein the inorganic insulating layer is disposed on the one surface and the side surface of the metal substrate.

8. A heat dissipation substrate comprising the laminate according to claim 1 .

9. A method for producing the laminate according to any one of claims 1 to 7, A method for manufacturing a laminate, comprising forming an inorganic insulating layer on one surface of a metal substrate in a thickness direction by using a vacuum film formation method.

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