Heat dissipation member and method for manufacturing the same, as well as heat sink and semiconductor device

Abstract

To provide heat dissipation components and the like that have excellent thermal conductivity in the thickness direction. [Solution] A heat dissipation member, etc., comprising a substrate and a multilayer film disposed on at least one surface of the substrate, wherein at least one layer of the multilayer film is a layer having a reststralen band between wavelengths of 10 and 100 μm.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a heat dissipation member, a method for manufacturing the same, a heat sink, and a semiconductor device.

BACKGROUND ART

[0002] A heat dissipation member is known as a member for efficiently releasing heat generated during operation of electrical and electronic equipment and the like to the outside. Thermal management is important because excessive heat causes performance degradation, failures, and the like of components. For example, Non-Patent Document 1 studies radiative heat transfer by HPhP in the reststrahlen band of α-MoO3.

PRIOR ART DOCUMENTS

NON-PATENT DOCUMENT

[0003]

NON-PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In some cases, a heat dissipation member is required to have improved thermal conductivity in the thickness direction.

[0005] The present disclosure has been made in view of such circumstances, and a problem to be solved by one embodiment of the present disclosure is to provide a heat dissipation member having excellent thermal conductivity in the thickness direction and a method for manufacturing the same. A problem to be solved by another embodiment of the present disclosure is to provide a heat sink and a semiconductor device including the above heat dissipation member.

MEANS FOR SOLVING THE PROBLEMS

[0006] The present disclosure includes the following aspects. <1> The invention comprises a substrate and a multilayer film disposed on at least one surface of the substrate, A heat dissipation member in which at least one layer of the multilayer film has a reststraene band between wavelengths of 10 and 100 μm. <2> The multilayer film consists of alternating layers: a first layer having a rest-stalene band between wavelengths of 10 and 100 μm, and a second layer having a different composition from the first layer. <1> The heat dissipation component described above. <3> The first layer includes at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides. <2> The heat dissipation component described above. <4> The second layer includes at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides. <3> The heat dissipation component described above. <5> The thickness of each layer constituting the multilayer film is 1 to 500 nm. The thickness of the multilayer film is 5 to 10,000 nm. <3> or <4> The heat dissipation component described above. <6> The first layer contains hexagonal boron nitride. <2> The heat dissipation component described above. <7> The second layer contains graphene, <6> The heat dissipation component described above. <8> The thickness of each layer constituting the multilayer film is 0.3 to 100 nm. The thickness of the multilayer film is 300-5000 nm. <6> or <7> The heat dissipation component described above. <9> The first layer has a refractive index of 1.05 to 1.6 at a wavelength of 10 μm and an extinction coefficient of 0.001 to 0.01. <2> ~ <8> A heat dissipation component described in any one of the following. <10> The base material is aluminum, stainless steel, copper, carbon sheet, glass, silicon carbide, aluminum nitride, or semiconductor. <1> ~ <9> A heat dissipation component described in any one of the following. <11> <1> ~ <10> A heat sink including a heat dissipation component as described in any one of the following. <12> <1> ~ <10> A semiconductor device comprising a heat dissipation component as described in any one of the following. <13> The process includes forming a multilayer film on a substrate using a physical vapor deposition method or a chemical vapor deposition method, A method for manufacturing a heat dissipation member, wherein at least one layer of the multilayer film is a layer having a reststralen band between wavelengths of 10 and 100 μm. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, a heat dissipation member having excellent thermal conductivity in the thickness direction and a method for manufacturing the same are provided. According to other embodiments of the present disclosure, a heat sink and a semiconductor device including the heat dissipation member are provided. [Modes for carrying out the invention]

[0008] [Heat dissipation component] The heat dissipation member of this disclosure comprises a substrate and a multilayer film disposed on at least one surface of the substrate, wherein at least one layer of the multilayer film is a layer having a reststralen band between wavelengths of 10 and 100 μm.

[0009] The inventors have found that by incorporating a layer having a reststalene band between wavelengths of 10 and 100 μm into a multilayer film, the thermal conductivity in the thickness direction is significantly improved compared to a single layer film. Within the reststalene band, surface phonon polaritons (SPhP) are excited when the distance between substrates is short, resulting in the existence of an evanescent field with a very high density of states. In multilayer films, these fields conduct thermal conductivity in the thickness direction through near-field thermal radiation, thereby improving thermal conductivity in the thickness direction. In this disclosure, "rest-stralen band" refers to a wavelength band in which the real part of the dielectric constant is negative and the imaginary part is positive.

[0010] <Base material> The heat dissipation member of this disclosure includes a base material. The type of the base material is not particularly limited. From the viewpoint of thermal conductivity, the base material is preferably aluminum, stainless steel, copper, carbon sheet, silicon carbide, or aluminum nitride, more preferably aluminum, copper, carbon sheet, silicon carbide, or aluminum nitride. From the viewpoint of mountability, glass or a semiconductor is also preferable as the base material.

[0011] <Multilayer Film> The heat dissipation member of the present disclosure includes a multilayer film. The multilayer film is disposed on at least one surface of the base material. The multilayer film may be disposed only on one surface of the base material, or may be disposed on both surfaces of the base material. Moreover, the multilayer film may be directly disposed on the base material, or another layer may be disposed between the base material and the multilayer film. Examples of the other layer include an adhesion layer, a thermal conductive layer, an insulating layer, and an electrically conductive layer.

[0012] The multilayer film refers to a film composed of two or more layers. The number of layers included in the multilayer film is 5 or more, preferably 9 or more, and more preferably 21 or more. Although the heat flux in the reststrahlen band increases by increasing the number of layers, the number of interfaces increases on the contrary, which may suppress phonon conduction and the like, so the number of layers is preferably 101 or less.

[0013] In the heat dissipation member of the present disclosure, at least one layer of the multilayer film is a layer having a reststrahlen band in a wavelength range of 10 to 100 μm.

[0014] Whether each layer has a reststrahlen band in a wavelength range of 10 to 100 μm can be determined by measurement using, for example, infrared spectroscopy such as FTIR, or spectroscopic ellipsometry.

[0015] In a layer having a reststalene band between wavelengths of 10 and 100 μm, the wavelength of the reststalene band is more preferably 12 to 50 μm, and even more preferably 15 to 45 μm. Furthermore, there may be multiple reststalene bands within the above wavelength range.

[0016] In the multilayer film, the number of layers having a reststralen band between wavelengths of 10 and 100 μm is 2 or more, preferably 4 or more, and more preferably 10 or more. While increasing the number of layers having a reststralene band between wavelengths of 10 and 100 μm increases the heat flux, it also increases the number of interfaces, which may suppress phonon conduction. Therefore, it is preferable to keep the number of layers to 50 or less.

[0017] Examples of layers having a reststralene band between wavelengths of 10 and 100 μm include layers containing at least one selected from the group consisting of alkali metal fluorides, alkaline earth metal fluorides, silicon carbide (SiC), and hexagonal boron nitride.

[0018] Examples of alkali metal fluorides include LiF, NaF, and KF. Examples of alkaline earth metal fluorides include CaF2 and MgF2.

[0019] From the viewpoint of improving thermal conductivity in the thickness direction, it is preferable that the multilayer film is constructed by alternately stacking a first layer having a reststralen band between wavelengths of 10 to 100 μm and a second layer having a different composition from the first layer.

[0020] Furthermore, "different constituent components" means that the types or amounts of components that make up the layers are different. The fact that the second layer has different constituent components from the first layer can be confirmed by performing elemental analysis on both the first and second layers.

[0021] The alternating layering of the first layer and the second layer, which has a different composition from the first layer, increases the thermal radiation component and improves thermal conductivity in the thickness direction.

[0022] If the first layer is a layer having a reststalene band between wavelengths of 10 and 100 μm, the second layer may be a layer having a reststalene band between wavelengths of 10 and 100 μm, or it may be a layer that does not fall under the category of a layer having a reststalene band between wavelengths of 10 and 100 μm. When both the first and second layers are layers having a reststalene band between wavelengths of 10 and 100 μm, the difference in wavelengths of the reststalene bands is preferably 1 to 50 μm.

[0023] The first layer having a reststralen band between wavelengths of 10 and 100 μm preferably has a refractive index of 1.05 to 1.6 at a wavelength of 10 μm and an extinction coefficient of 0.001 to 0.01 at a wavelength of 10 μm. The refractive index of the first layer at a wavelength of 10 μm is preferably 1.1 to 1.55, and more preferably 1.1 to 1.4. The extinction coefficient of the first layer at a wavelength of 10 μm is preferably 0.001 to 0.0085, and more preferably 0.002 to 0.0085. Furthermore, the refractive index of the second layer at a wavelength of 10 μm is preferably 0.5 to 1.5, and more preferably 0.5 to 1.35. The extinction coefficient of the second layer at a wavelength of 10 μm is preferably 0.001 to 20, and more preferably 0.001 to 0.01. Furthermore, especially when the second layer contains alkali metal fluoride or alkaline earth metal fluoride, the refractive index of the second layer at a wavelength of 10 μm is preferably 1.1 to 1.55, more preferably 1.1 to 1.4, and the extinction coefficient of the second layer at a wavelength of 10 μm is preferably 0.001 to 0.02, more preferably 0.001 to 0.009. Furthermore, especially when the second layer contains graphene, the refractive index of the second layer at a wavelength of 10 μm is preferably 0.5 to 0.9, and the extinction coefficient of the second layer at a wavelength of 10 μm is preferably 10 to 25, and more preferably 15 to 20.

[0024] When using at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, the difference in refractive index between the first and second layers is preferably 0.05 to 0.5 from the viewpoint of improving thermal conductivity in the thickness direction. From the viewpoint of improving thermal conductivity in the thickness direction, the difference in extinction coefficients between the first and second layers is preferably 0.001 to 0.01. When using a two-dimensional layered material such as hexagonal boron nitride, the difference in refractive index between the first and second layers is preferably 0.5 to 1.5, from the viewpoint of improving thermal conductivity in the thickness direction. From the viewpoint of improving thermal conductivity in the thickness direction, the difference in extinction coefficients between the first and second layers is preferably 15 to 19.

[0025] In this disclosure, the refractive index and extinction coefficient are measured, for example, using infrared spectroscopy such as FTIR or spectroscopic ellipsometry.

[0026] Two preferred embodiments of a multilayer film in which the first and second layers are alternately stacked are as follows:

[0027] (Aspect 1) The first layer preferably contains at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides.

[0028] The second layer preferably contains at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides. If both the first and second layers contain at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, it is preferable that the first and second layers have different types of constituent components.

[0029] The following are examples of combinations of the first and second layers. 1st layer: CaF2, 2nd layer: LiF 1st layer: CaF2, 2nd layer: MgF2 1st layer: MgF2, 2nd layer: LiF

[0030] The thickness of each layer constituting the multilayer film is preferably smaller than the wavelength of the restoralene band. More specifically, it is preferably 1 to 500 nm, more preferably 10 to 300 nm, and even more preferably 50 to 100 nm. By setting the thickness within this range, near-field thermal radiation conduction can be further promoted. The thickness of the multilayer film is preferably 5 to 10,000 nm, more preferably 5 to 2,500 nm, even more preferably 50 to 1,500 nm, and still more preferably 250 nm to 500 nm. The thickness of each layer, and the thickness of the multilayer film, are measured, for example, by preparing cross-sectional sections of the multilayer film using focused ion beam processing, and then measuring them using an electron microscope (SEM) or a transmission electron microscope (TEM).

[0031] (Aspect 2) The first layer preferably contains hexagonal boron nitride.

[0032] The second layer preferably contains graphene.

[0033] The following are examples of combinations of the first and second layers. Layer 1: Hexagonal boron nitride, Layer 2: Graphene

[0034] The thickness of each layer constituting the multilayer film is preferably 0.3 to 500 nm, more preferably 0.3 to 100 nm, and even more preferably 0.3 to 50 nm. The thickness of the multilayer film is preferably 300 to 5000 nm, more preferably 300 to 1100 nm, even more preferably 500 to 1100 nm, and particularly preferably 700 to 1100 nm.

[0035] <Application> The heat dissipation member of this disclosure can be used for heat dissipation measures in electrical and electronic equipment. The heat dissipation member of this disclosure can be applied to heat sinks and semiconductor devices.

[0036] [Manufacturing method for heat dissipation components] The method for manufacturing the heat dissipation member of this disclosure includes the step of forming a multilayer film on a substrate using a physical vapor deposition method or a chemical vapor deposition method, wherein at least one layer of the multilayer film is a layer having a reststraene band between wavelengths of 10 and 100 μm.

[0037] Details of the substrate and multilayer film are as described above.

[0038] Examples of physical vapor deposition methods include vacuum deposition, ion plating, and sputtering. Examples of chemical vapor deposition methods include thermal CVD (Chemical Vapor Deposition) and plasma CVD.

[0039] The heat dissipation member manufactured by the heat dissipation member manufacturing method of this disclosure has excellent thermal conductivity in the thickness direction because at least one layer of the multilayer film has a reststralen band between wavelengths of 10 and 100 μm. [Examples]

[0040] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. Examples 1-1 to 1-8 and Examples 2-1 to 2-4 are examples, and Examples 1-9 to 1-12 and Examples 2-5 to 2-6 are comparative examples.

[0041] <Examples 1-1 to 1-12> In Examples 1-1 to 1-8, the heat flux values ​​were calculated for a multilayer film consisting of a first layer / second layer / first layer / second layer / first layer as shown in Table 1. In Examples 1-9 to 1-12, the heat flux values ​​for the single-layer films shown in Table 1 were calculated. The calculation method used was a fluctuating electromagnetic simulation (reference: Chen et al. Computer Physics Communications, 231(2018)163-172). Specifically, the layers emitting and receiving thermal radiation were distinguished at the center of each structure, and temperatures were set for each. Furthermore, the film thickness and dielectric function based on literature values ​​were input for each layer to model the multilayer structure. This allowed the heat flux emitted from the high-temperature side to the low-temperature side to be derived.

[0042] In Table 1, "Thickness of the first layer" refers to the individual thicknesses of the first layer. "Thickness of the second layer" refers to the individual thicknesses of the second layer.

[0043] [Table 1]

[0044] As shown in Table 1, Examples 1-1 to 1-8 showed higher heat flux values ​​and superior thermal conductivity in the thickness direction compared to Examples 1-9 to 1-12.

[0045] <Examples 2-1 to 2-6> Examples 2-1 to 2-4 calculated the heat flux values ​​for a multilayer film in which the first and second layers are alternately stacked, as shown in Table 2. In all cases, the outermost layer is the first layer. In Examples 2-5 to 2-6, the heat flux values ​​for the single-layer films shown in Table 2 were calculated. The calculation method is the same as in Examples 1-1 to 1-12.

[0046] [Table 2]

[0047] As shown in Table 2, Examples 2-1 to 2-4 showed higher heat flux values ​​and superior thermal conductivity in the thickness direction compared to Examples 2-5 to 2-6.

Claims

1. The invention comprises a substrate and a multilayer film disposed on at least one surface of the substrate, A heat dissipation member wherein at least one layer of the multilayer film has a reststraene band between wavelengths of 10 and 100 μm.

2. The heat dissipation member according to claim 1, wherein the multilayer film is made up of alternating layers of a first layer having a reststralen band between wavelengths of 10 to 100 μm and a second layer having a different composition from the first layer.

3. The heat dissipation member according to claim 2, wherein the first layer includes at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides.

4. The heat dissipation member according to claim 3, wherein the second layer includes at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides.

5. The thickness of each layer constituting the multilayer film is 1 to 500 nm. The heat dissipation member according to claim 3, wherein the thickness of the multilayer film is 5 to 10,000 nm.

6. The heat dissipation member according to claim 2, wherein the first layer contains hexagonal boron nitride.

7. The heat dissipation member according to claim 6, wherein the second layer includes graphene.

8. The thickness of each layer constituting the multilayer film is 0.3 to 100 nm. The heat dissipation member according to claim 6, wherein the thickness of the multilayer film is 300 to 5000 nm.

9. The heat dissipation member according to claim 2, wherein the first layer has a refractive index of 1.05 to 1.6 at a wavelength of 10 μm and an extinction coefficient of 0.001 to 0.

01.

10. The heat dissipation member according to any one of claims 1 to 9, wherein the base material is aluminum, stainless steel, copper, carbon sheet, glass, silicon carbide, aluminum nitride, or a semiconductor.

11. A heat sink comprising the heat dissipation member described in claim 1.

12. A semiconductor device comprising the heat dissipation member described in claim 1.

13. The process includes forming a multilayer film on a substrate using a physical vapor deposition method or a chemical vapor deposition method, A method for manufacturing a heat dissipation member, wherein at least one layer of the multilayer film is a layer having a reststraene band between wavelengths of 10 and 100 μm.

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