JP2001358262A - Thermal conduction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a thermal resistance of a sheet having both a thermal conductivity and EMC function by reducing the thickness. SOLUTION: A thermal conduction material 10 is a thermal conduction base material 11 laminated with a magnetic foil 12. In installing the thermal conduction material 10, the magnetic foil 12 serves as a supporting material and supports the thermal conduction base material 11, allowing the thermal conduction material 10 to be handled easily and thus increasing the workability. Because the magnetic foil 12 supports the thermal conduction base material 11 and compensates for an insufficient strength of the thermal conduction base material 11, excessive deformation or damage of the thermal conduction base material 11 can be prevented and thereby the thickness of the thermal conduction base material 11 can be 500 μm or below. As a result, a thermal resistance is lowered dramatically, which increases a quantity of heat per unit time transferred from an electronic component to the heat sink and thereby a heat radiation effect of the thermal conduction material 10 is increased. The EMC function is performed by the magnetic foil 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of heat conductive materials.

[0002]

2. Description of the Related Art Many electronic components such as CPUs and LSs
A heat sink such as a heat sink is attached to the I, IC, power transistor, and the like in order to efficiently release generated heat. If the heat sink is not in good contact with, for example, the outer surface of the CPU (if there is a gap), the heat radiation efficiency is reduced. Therefore, an interface material having good thermal conductivity is filled between the heat sink and the CPU to prevent the gap. . For example, silicone gel has been used as the heat conductive material as the interface material.

In addition, since electromagnetic waves (noise) are emitted from a CPU or the like, an electromagnetic wave shield (EMC) is required. Under such circumstances, a sheet having good thermal conductivity and EMC function has been demanded as the interface material. Examples of such a sheet include a sheet of a silicone gel using a magnetic material as a filler, a sheet obtained by kneading a heat conductive material and a sheet obtained by kneading a magnetic material.

[0004]

By the way, it is known that the relationship shown in the following equation 1 holds for the amount of heat transfer (Q) by the plate-shaped heat conductive substrate.

[0005]

(Equation 1)

Q: heat transfer amount λ: thermal conductivity [Kcal / mh ° C.] Q ₁ -Q ₂ : temperature difference between front and back x: plate thickness F: surface area T: time Therefore, to increase the heat transfer efficiency (heat transfer amount) To increase Q), a material having a good thermal conductivity λ may be used or the thickness x may be reduced.

[0007] By the way, the improvement of the thermal conductivity λ (that is, the improvement of the thermal conductive material) usually requires a great deal of research.
High human and financial burden. There is also a feeling that they have been thoroughly studied by their predecessors. On the other hand, the method of reducing the plate thickness x is rather easy. However, when the thickness x of the heat conductive base material is reduced, for example, there is a problem that the rigidity is reduced and the handling becomes difficult.

For example, when a silicone gel or a material obtained by adding a filler with a silicone gel as a base material is processed into a sheet shape, the physical property (strength) of the silicone gel is 500
It is extremely difficult to reduce the thickness to less than μm (0.5 mm), and even if the thickness can be processed to such a thickness, the strength is so low that the material collapses and becomes unusable. This problem was not limited to the silicone gel, but was the same for other heat conductive substrates.

For this reason, when a sheet having both thermal conductivity and EMC function is manufactured using a heat conductive base material such as silicone gel, the sheet thickness is reduced (for example, to 0.5 mm or less), and The heat transfer amount Q shown in No. 1 could not be increased. Also, laminating different types of sheets in order to provide thermal conductivity and EMC function has a disadvantage that the manufacturing cost is high.

[0010] Further, since the silicone gel is solid under the temperature conditions when it is used by mounting it on an electronic component,
There is also a problem that the shape does not follow the shape of the CPU or the heat sink, and a small gap is generated between the surface of the CPU and the surface of the heat sink. there were.

When a conventional heat conductive base material such as silicone gel is used, it is firmly attached to an electronic component and a heat sink with an adhesive or the like. Has to separate the heat sink and the electronic components in a destructive manner, and one or both of them cannot be reused.

The present invention aims at lowering the thermal resistance by reducing the thickness of a sheet having both heat conductivity and EMC function.

[0013]

[Problems to be solved by the invention]

[0014]

Means for Solving the Problems and Effects of the Invention The heat conductive material according to claim 1 for solving the above problems is a plate having a thickness of 500 μm or less when pressed toward another solid surface. It is characterized by comprising a heat conductive base material having a property of being deformed following the shape of the solid surface, and a magnetic foil laminated on two or one surface of the heat conductive base material.

Since the magnetic foil is laminated on two or one surface of the heat conductive base material, the magnetic foil serves as a support to compensate for the insufficient strength of the heat conductive base material and prevent excessive deformation and breakage thereof. .
Therefore, the thickness of the heat conductive substrate can be reduced to 500 μm or less. As a result, the thermal resistance is remarkably reduced, so that the amount of heat transferred from the electronic component (for example, CPU) to the heat sink per time is increased, and the heat dissipation is improved. In addition, when the heat conductive material is attached to, for example, the surface of the CPU, handling is simplified, and workability is improved.

In addition, since the magnetic foil provides an EMC effect, noise from electronic components (eg, CPU) can be prevented. Since the lamination of the magnetic foil and the heat conductive substrate can be performed by a simple operation such as a hot press, the processing is not difficult and the processing cost can be reduced.

When the heat conductive base material is pressed against another solid surface, it has the property of being deformed following the shape of the solid surface. The pinching force = the pressing force causes the heat conductive substrate to deform following the surface shapes of both the electronic component and the heat sink. The magnetic foil also deforms following the surface shape of the electronic component or the heat sink. Therefore, the heat conductive material is in close contact with both the electronic component serving as the heat source and the heat sink for heat radiation, and there is no minute gap between the heat conductive material and the surface of the electronic component and the heat sink. A heat conduction effect is obtained.

Examples of deformations following the surface shape when pressed against the solid surface include plastic deformation and elastic deformation. That is, plasticity and elasticity are exemplified as the property of such deformation. The material of the magnetic foil is not particularly limited, and a foil of a known magnetic material can be used. Some examples are Fe-Ni alloy (trade name: Permalloy), silicon steel (Fe-Si), Fe-Cr alloy (for example, stainless steel), sendust (Fe-Al-Si), and permendur (Fe-Co). Etc.

Since the magnetic foil is laminated on two or one surface of the heat conductive substrate, the magnetic foil and the electronic component or the heat sink are only in surface contact with each other and can be easily separated. For this reason, when separating an electronic component (for example, a CPU) from a heat sink for upgrading, maintenance, repair, or the like such as expansion of a memory, it is necessary to separate the heat sink and the electronic component by a destructive method. However, for example, the replaced electronic component or heat sink can be reused (recycled).

If the thickness of the heat conductive base material is 500 μm or less, good heat transfer efficiency can be obtained, but it goes without saying that the thinner the heat conductive base material, the better. Therefore, preferably 20
0 μm or less. However, if the thickness is too small, the possibility of breakage during the mounting operation increases even if there is a magnetic foil. Therefore, it is preferable that the thickness of the heat conductive base material be 100 μm or more. That is, the thickness of the heat conductive substrate is 100 to 200.
It is preferred to be in the range of μm.

Similarly, the thinner the magnetic foil, the better from the viewpoint of heat conduction. However, if the thickness is too small in relation to the physical properties of the heat conductive substrate, the strength may be insufficient, which is not good. Also, there is a limit to how thin the foil can be processed. Therefore, depending on the physical properties of the heat conductive base material and the physical properties of the magnetic foil (mainly the mechanical strength of both of them), the thickness of the magnetic foil is 50 μm or less.
It is preferably at least μm.

[0022] More preferably, the total thickness of the heat conductive base material and the magnetic foil, that is, the thickness of the heat conductive material is defined as claim 4.
As described above, the thickness is preferably 200 μm or less. The magnetic foil may be laminated on both sides of the heat-conducting substrate, so that it is very easy to separate the electronic components from the heat sink. Also, the strength of the heat conductive material is increased.

However, laminating on both sides increases the thickness of the heat conductive material by that much, and has a disadvantage in terms of heat transfer performance (thermal resistance). In addition, since they are laminated on two surfaces, the processing cost also increases. In view of these things, claim 2
As described, a configuration in which the magnetic foil is laminated on only one surface of the heat conductive substrate is preferable.

In the case of a structure in which only one surface is laminated, there is a possibility that the surface without the magnetic foil is in close contact with the electronic component or the heat sink, and it is difficult to separate the electronic component or the heat sink. For this reason, for example, when the heat conductive material is kept mounted when it is reused, it is not necessary to newly mount the heat conductive material.

According to a fifth aspect of the present invention, in the heat conductive material according to any one of the first to fourth aspects, the heat conductive base material comprises an organic material and a filler having a higher thermal conductivity than the organic material. And at least 3 times the temperature band at all times.
It is characterized by plasticizing at 0 to 65 ° C. and deforming flexibly following the surface shape of the contacting partner.

The heat conductive material is plasticized (softened) at least in a temperature range of 30 to 65 ° C., which is always used, and
Because it deforms flexibly following the surface shape of the contacting partner, when it is used at room temperature, for example, it is a rubber-like substance with appropriate hardness and does not stick to hands etc. The work of arranging the material near the electronic component is easy.

Further, for example, when the temperature of the electronic component rises and the temperature of the heat conductive material reaches 30 to 60 ° C., the heat conductive material is plasticized and follows the shape of the electronic component with which it comes into contact, and becomes flexible. Deforms and adheres to the surface of the electronic component. Since this heat conductive material has high thermal conductivity, it can efficiently remove heat from the electronic component and radiate heat, thereby suppressing an increase in the temperature of the electronic component.

Further, when the temperature of the electronic component is reduced to, for example, room temperature by turning off the electronic component, the heat conductive material is
Since the state changes from a softened state to a solidified state, for example, a rubbery state, the operation of peeling the heat conductive material from the electronic component is extremely easy. Here, plasticizing means softening by heat (to the extent that it can follow the surface shape of the contact partner).

The heat conductive material according to claim 6 is the heat conductive material according to claim 5, wherein the heat conductor is at 60 ° C.
, Is characterized by plasticizing when a pressure of 6.0 g / cm ² or more is applied and flexibly deforming following the surface shape of the contacting partner.

The heat conductive material has a temperature of 6.0 at 60 ° C.
g / cm ² or more, when it is plasticized, it is plasticized and follows the surface shape of the contacting partner and deforms flexibly.
The same effects (improvement in workability and heat radiation) as described in claim 5 can be obtained. The heat conductive substrate according to claim 6 can be obtained if the following conditions a, b, and c are satisfied.

A. The melting point of the organic material is in the range of 30 to 70 ° C. b. The viscosity of the organic material at 100 ° C. is 70,000 cP
That is all. c. The ratio of the filler to the entire heat conductive substrate is 30 to 90.
Be in the range of weight%.

The organic material serving as the base material of the heat conductive base material is an olefin resin, specifically, an olefin resin such as vinyl acetate-ethylene copolymer, polyethylene, polyisobutylene, ethylene-ethyl alcohol and the like. Satisfying the above conditions (melting point is 30 to 70 ° C., viscosity at 100 ° C. is 70,000 cP or more), molecular weight 7
Examples include 000 to 50,000 unvulcanized EPDM (unvulcanized ethylene-propylene rubber), but any material that satisfies the above melting point and viscosity conditions can be used without any particular limitation.

As the filler, ceramics, one of which is soft ferrite, metal powder, metal magnetic material, carbon fiber and the like can be used. Since ceramics have high thermal conductivity, the thermal conductivity of the thermally conductive substrate can be enhanced. Examples of ceramics include silicon carbide, boron nitride, alumina, aluminum hydroxide, zinc oxide, magnesia, magnesium hydroxide, silicon nitride, aluminum nitride, and the like.

Examples of the soft ferrite include Ni-Zn ferrite and Mn-Zn ferrite. Since soft ferrite has a high magnetic shielding effect, by using this as a filler, the heat conductive substrate can also have an EMC function. In the case of metal powder, gold, silver, copper, aluminum and the like can be used. Since these metal powders have a high thermal conductivity and an excellent electric field shielding effect, by using them as a filler, it is possible to realize a heat conductive base material having an excellent EMC function due to the heat conduction effect and the electric field shielding effect.

As the metal magnetic material, silicon steel (Fe—S)
i), Permalloy (trade name), Sendust (Fe-Al
-Si), permendur (Fe-Co), and Fe-Cr alloys such as stainless steel. Since such a metal magnetic material has a high magnetic shielding effect, by using these as a filler, it is possible to realize a heat conductive base material having an excellent EMC function due to the magnetic shielding effect.

The carbon fibers are PAN type, pitch type, VGC
F, graphite, curl, and the like can be used. Since carbon fibers have a high thermal conductivity and a high electric field shielding effect at the same time, by using them as a heat conducting substrate, a heat conducting substrate excellent in both the heat conducting effect and the electric field shielding effect can be realized.

The filler is not limited to those exemplified above. In addition, one type of filler may be used alone, or a plurality of types may be mixed. As the shape of the constituent unit of the filler, a granular one, a flake-like one, a fibrous one or the like can be used.

The melting point of the organic material constituting the heat conductive substrate is 3
Since the temperature is in the range of 0 to 70 ° C., the organic material is liquefied when heated above this melting point. However, 10 of organic materials
Since the viscosity at 0 ° C. is 70,000 cP or more, the viscosity is higher near the melting point. For this reason, even if it liquefies because it has a melting point or higher, it is in a state where it is extremely difficult to flow.
In addition, the filler dispersed in the organic material prevents excessive fluidization of the organic material. Therefore, the heat conductive base material exhibits plasticity such as clay. The plasticity (fluidity) of the heat conductive substrate in a state where the organic material is liquefied can be adjusted by the mixing ratio of the filler. In this case, depending on the type (combination) of the organic material and the filler, the compounding ratio of the filler is preferably in the range of 30 to 90% by weight of the heat conductive substrate.

Since the material has plasticity at a relatively low temperature (above the melting point of the organic material), it is heated above the melting point of the organic material while being in contact with the surface of the electronic component, and follows the surface shape of the electronic component. And can be plastically deformed. That is, the heat conductive material can be brought into close contact with the surface of the electronic component. In that case, if the heat conductive base material is sandwiched between the electronic component and the heat sink, the heat conductive material can be adhered to both the electronic component and the heat sink.

If the melting point of the organic material is set to be high (a temperature close to 70 ° C.), the possibility that the heat conductive base material has plasticity in a normal use state of the electronic component is low. In this case, the electronic component may be used after the heat conductive material is sandwiched between the electronic component and the heat sink and plasticized to make them adhere to each other as described above.

If the melting point of the organic material is set low (a temperature close to 30 ° C.), the heat is raised by heat from the electronic component in contact with the heat conductive material, so that the heat conductive base material has plasticity. And it deforms following the surface shape of an electronic component and a heat sink, and adheres well to an electronic component and a heat sink.
As described above, since the viscosity is high, the component does not flow out (drip) due to heat generation of the electronic component.

Depending on the degree of heat generation of the electronic component and the setting of the melting point of the organic material, the above two types can be used. In any case, the heat conductive material can be brought into good contact with the electronic component and the heat sink. . As a result, the heat conduction efficiency through the heat conductive material is improved, and the heat of the electronic component can be radiated well.

Further, since the deformation is made in accordance with the surface shapes of the electronic component and the heat sink, the load applied from the heat sink to the electronic component is evenly distributed, so that an uneven load is not applied to a part of the electronic component. Furthermore, if an organic material having plasticity at normal temperature is used, when a heat conductive material is applied to the surface of an electronic component, for example, it can be plastically deformed by following the surface shape of the electronic component. Adhesion when the organic material is liquefied becomes better.

In particular, if the heat conductive material is prepared to be plasticized under the conditions of use of the heat conductive material, the heat conductive material is expanded when the heat of the electronic component expands the magnetic foil (linear expansion). Since it is plastically deformed in response to this, there is no problem such as peeling or wrinkling of the magnetic foil due to the difference in thermal expansion coefficient between the two.

In a conventional heat conductive material in which a sheet of a silicone gel (heat conductive base material) and a sheet having an EMC function are laminated, problems such as peeling due to a difference in thermal expansion coefficient between the two sheets can be avoided. Did not. In comparison, it can be said that the effect of the heat conductive material of the present invention exerted by the above properties (the heat conductive base material is plasticized under use conditions) is an extremely excellent effect.

[0046]

Next, an embodiment of the present invention will be described with reference to an embodiment of the present invention.

[0047]

EXAMPLES (Thermal Conductive Substrate) The following organic materials and fillers were kneaded using a two-roll kneader, then molded and formed into a sheet-like thermal conductive substrate (Examples 1 and 2; Examples 1 and 2) were obtained. Comparative Example 1 is an unvulcanized EPD as an organic material.
M is formed alone to form a sheet. The heat conductive base materials of Examples 1 and 2 and Comparative Example 2 have a structure in which a filler is dispersed in an organic material as illustrated in FIG. <Example 1> Unvulcanized EPDM (organic material): 100 parts by weight SiC (filler): 230 parts by weight <Example 2> Unvulcanized EPDM (organic material): 100 parts by weight BN (filler): 120 Parts by weight <Comparative Example 1> Unvulcanized EPDM only <Comparative Example 2> Paraffin (molecular weight: 1000) (organic material): 100 parts by weight Al2O3 (filler): 150 parts by weight These Examples 1, 2 and Comparative Examples 1 and 2 The properties of the heat conductive substrate No. 2 are as shown in Table 1. The viscosity was measured using a B-type viscometer, and the thermal conductivity was measured using a thermal conductivity meter QTM-500 sold by Kyoto Electronics Industry.

[0048]

[Table 1]

Here, the dripping means a phenomenon in which the heat conductive base material flows and flows out when the heat conductive base material is used between the electronic component and the heat sink. As is clear from Table 1, the heat conductive base materials of Examples 1 and 2 have high thermal conductivity and do not cause dripping even at 100 ° C., which is much higher than the melting point of the organic material.

On the other hand, in the case of Comparative Example 1, dripping occurred at 100 ° C. This indicates that the use of the filler is effective for preventing dripping. Further, the heat conductive base material of Comparative Example 2 has a low heat conductivity and dripping at 100 ° C. (Plasticization Experiment) Experiments were conducted to confirm the softened state of the heat conductive base materials of Examples 1 and 2.

In this experiment, the heater is turned on with the heat conductive material placed on the heater and the block (block 1 or block 2) placed thereon, and the temperature of the heat conductive material becomes 60 ° C. Was set as follows. As the block 1, a block having a specific gravity of 1 of 3 × 3 × 6 cm ² was used. Since the weight of the block 1 is 54 g and its bottom area is 9 cm ² , the pressure applied to the heat conductive material is 54 ÷ 9 = 6 g / cm 2.

As block 2, 3 × 3 × 6 cm^Two
A block having a specific gravity of 9 was used. Weight of this block 2
Is 486g and its bottom area is 9cm^TwoSo the heat conduction
The pressure applied to the material is 486 ÷ 9 = 54 g / cm^TwoIn
You. As a result of this experiment, when the temperature of the heat conducting material is 60 ° C.
And the applied pressure is 6 g / cm ^TwoAnd 54g / cm^TwoNoto
And therefore the applied pressure is 6 g / cm^TwoThen,
The heat conductive substrate plasticizes and follows the surface shape of the contact partner
It was confirmed that it deformed flexibly. (Thermal Conductive Material) Using the thermal conductive base material of Examples 1 and 2,
Thus, a heat conductive material having a structure shown in FIG. 2A was manufactured. this
The heat conducting material 10 is the heat conducting material of the first embodiment (or the second embodiment).
It is composed of a base material 11 and a magnetic foil 12.

In this example, the heat conductive material 10 was manufactured by placing the magnetic foil 12 on the sheet-shaped heat conductive base material 11 and pressing it while heating it to about 100 ° C. to bring them into close contact with each other. The magnetic foil 12 was made of Permalloy (trade name) and had a thickness of 20 μm, and was manufactured with the thickness of the heat conductive material 10 (the heat conductive substrate 11 + magnetic foil 12) at the time of completion set to 200 μm. FIG. 2 schematically shows a cross-sectional structure of the heat conductive material 10 and does not reflect actual dimensions.

The heat conductive material 10 is inserted between the electronic component and the heat sink with the magnetic foil 12 facing the heat sink. The mounting procedure is as follows. First, the surface of the heat conductive material 10 where the magnetic foil 12 is not present and the heat conductive base material 11 is exposed (the lower surface in FIG. 2A) is brought into contact with the heat radiating surface of the electronic component (eg, CPU).
Heat to about 00 ° C. Then, the heat conductive base material 11 is plasticized and adheres to the heat dissipation surface of the electronic component. Further, the thermally conductive base material 11 once adhered is hard to peel off (substantially does not peel off) from the electronic component.

Thereafter, a heat sink is applied to the magnetic foil 12 side, and the magnetic foil 12 is fixed to the electronic component with screws or the like. The force of the screw or the like (for example, a tightening force) acts as a force (a holding force) for holding the heat conductive material 10 between the heat sink and the electronic component. The heat conductive material 10 is a plate having a thickness of 500 μm or less (about 200 μm in the embodiment), and the heat conductive base material 11 is deformed following the surface shape of the electronic component or the heat sink when pressed against the surface. When the heat conductive material 10 is sandwiched between the electronic component and the heat sink, the heat conductive base material 11 is deformed following the surface shapes of both the electronic component and the heat sink by the sandwiching force = pressing force. The magnetic foil 12 also deforms following the surface shape of the heat sink. As a result, the heat conductive material 10 comes into close contact with both the electronic component serving as a heat source and the heat sink for heat dissipation. Since there is no minute gap between the heat conductive material 10 and the surfaces of the electronic component and the heat sink, a sufficient heat conductive effect can be obtained.

The heat conducting material 10 may not be heated before the heat sink is attached, but may be heated after the heat sink is attached to plasticize the heat conducting substrate 11. Alternatively, it may be heated and plasticized before and after the attachment of the heat sink. Alternatively, if the heat conductive base material 11 is heated by the heat generated by the use of the electronic component, the heat conductive base material 11 is plasticized by the heat and adheres to the surface of the electronic component and the heat sink. As a result, the heat conduction efficiency through the heat conductive material 10 is improved, and the heat of the electronic component can be radiated well.

In addition, since the deformation is made to closely follow the surface shapes of the electronic component and the heat sink, the load applied from the heat sink to the electronic component is evenly distributed, so that an uneven load is not applied to a part of the electronic component. In mounting the heat conductive material 10, the magnetic foil 12 serves as a supporting material to support the heat conductive base material 11, so that it is easy to handle and workability is improved. Since the magnetic foil 12 serves as a support and compensates for the insufficient strength of the heat conductive base material 11 and prevents its excessive deformation or breakage, the thickness of the heat conductive base material 11 is set to 500 μm or less (200 μm or less in the embodiment). It is possible to do. As a result, the thermal resistance is significantly reduced, so that electronic components (for example, CP
The amount of heat transfer per unit time from U) to the heat sink increases, and the heat dissipation is improved.

Since the magnetic foil 12 has good thermal conductivity, it does not hinder conduction from the electronic components to the heat sink. Further, since the magnetic foil 12 has an EMC effect, electronic components (for example, C
PU) can be shielded well. Alternatively, noise from outside to the electronic component can be shielded.

The lamination of the magnetic foil 12 and the heat conductive substrate 11
Since it is possible with a simple operation such as a heating press, the processing is not difficult and the processing cost can be reduced. This heat conductive material 1
In the case of No. 0, the heat conductive base material 11 is adhered to the electronic component by utilizing the plasticization of the heat conductive base material 11 by heating.

However, since the magnetic foil 12 is laminated on the other surface of the heat conductive substrate 11, the magnetic foil 12 and the heat sink only come into surface contact with each other and can be easily separated.
For this reason, electronic components (for example, C
When separating the PU and the heat sink, it is not necessary to separate the heat sink and the electronic component by a destructive method, and for example, the replaced electronic component or the heat sink can be reused (recycled).

In particular, the melting point of the organic material is low (Example 4
5 ° C.), the viscosity at 100 ° C. is as high as 70,000 cP, and the filler is dispersed in the organic material. It does not flow easily and does not drip during use.

Further, since the heat conductive base material 11 has plasticity at a relatively low temperature (above the melting point of the organic material), it is plasticized by the heat of the electronic component during use and plastically deforms to follow the surface shape, thereby deforming the surface of the electronic component. Adhere to Therefore, there is an effect that the degree of adhesion to the electronic component is increased during use.

Further, since the heat conductive base material 11 is plasticized under the use conditions of the heat conductive material 10, the heat of the electronic component causes the magnetic foil 1
When 2 expands (linearly expands), the heat conductive base material 11 is plastically deformed in response to the expansion, so that problems such as peeling or wrinkling of the magnetic foil 12 due to a difference in thermal expansion coefficient between the two do not occur. .

As shown in FIG. 2B, a structure in which the magnetic foil 12 is laminated on both surfaces of the heat conductive base material 11 is also possible. In this way, it can be easily separated from both the electronic component and the heat sink. Although the present invention has been described above, the present invention is not limited to the above-described examples, and it goes without saying that various embodiments can be made without departing from the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the internal structure of a heat conductive substrate of an example.

FIG. 2 is an explanatory diagram of a heat conductive material using the heat conductive base material of the example.

[Explanation of symbols]

 Reference Signs List 10 heat conductive material 11 heat conductive base material 12 magnetic foil

Claims (6)

[Claims] 1. A heat conductive base material having a property of deforming following the shape of a solid surface when pressed toward another solid surface in a plate shape having a thickness of 500 μm or less; And a magnetic foil laminated on two or one of the surfaces. 2. The heat conductive material according to claim 1, wherein the magnetic foil is laminated only on one surface of the heat conductive base material. 3. The heat conductive material according to claim 1, wherein the thickness of the magnetic foil is 50 μm or less and 5 μm or more. 4. The heat conductive material according to claim 1, wherein the heat conductive material has a thickness of 200 μm or less. 5. The heat conductive material according to claim 1, wherein the heat conductive base material contains an organic material and a filler having a higher thermal conductivity than the organic material. A heat conducting material characterized by being plasticized at a temperature range of 30 to 65 ° C. in a working temperature range and flexibly deformed following the surface shape of a contact partner. 6. The heat conductive material according to claim 5, wherein the heat conductor is plasticized when a pressure of 6.0 g / cm ² or more is applied at 60 ° C., and the heat conductive material is brought into contact with the surface shape of the mating member. A heat conductive material characterized by flexible deformation following it.