WO2018147228A1 - Electromagnetic wave-suppressing heat transfer sheet, method for producing electromagnetic wave-suppressing heat transfer sheet, and semiconductor device - Google Patents

Abstract

Provided is an electromagnetic wave-suppressing heat transfer sheet which exhibits high adhesion to a heat source or a heat dissipation member, while having excellent heat conductivity and electromagnetic wave suppression effect. In order to solve the above-described problem, an electromagnetic wave-suppressing heat transfer sheet 1 according to the present invention contains a binder resin 11 and a fibrous heat conductive filler 12, and is characterized in that this electromagnetic wave-suppressing heat transfer sheet 1 is obtained by connecting a vertically aligned body 10a, in which the heat conductive filler 12 is aligned in a direction T that is generally perpendicular to a sheet surface S, and a horizontally aligned body 10b, in which the heat conductive filler 12 is aligned in a direction that is generally parallel to the sheet surface S, with each other within the same plane.

Description

Electromagnetic wave suppressing heat conductive sheet, method for manufacturing electromagnetic wave suppressing heat conductive sheet, and semiconductor device

The present invention relates to an electromagnetic wave suppressing heat conductive sheet, an electromagnetic wave suppressing heat conductive sheet manufacturing method, and a semiconductor device having excellent thermal conductivity and electromagnetic wave suppressing effect.

In recent years, electronic devices have been trending toward miniaturization, but the power consumption cannot be changed so much due to the variety of applications.

As a heat dissipation measure in the electronic devices described above, a heat sink made of a metal material having a high thermal conductivity such as copper or aluminum, a heat pipe, a heat sink, and the like are widely used. These heat dissipating parts having excellent thermal conductivity are arranged so as to be close to electronic parts such as a semiconductor package, which is a heat generating part in the electronic equipment, in order to achieve a heat radiation effect or temperature relaxation in the equipment. Moreover, these heat dissipation components excellent in thermal conductivity are arranged from the electronic component which is a heat generating portion to a low temperature place.

However, the heat generating part in the electronic device is an electronic component such as a semiconductor element having a high current density, and the high current density is considered to have a large electric field strength or magnetic field strength that can be a component of unwanted radiation. For this reason, when a heat dissipating part made of metal is disposed in the vicinity of the electronic component, there is a problem that heat is absorbed and harmonic components of an electric signal flowing through the electronic component are picked up. Specifically, since the heat dissipating part is made of a metal material, it itself functions as a harmonic component antenna or acts as a transmission path for harmonic noise components.

In order to solve such a problem, a technique for incorporating a magnetic material for breaking the coupling of a magnetic field into a heat conductive sheet has been developed.
For example, Patent Document 1 discloses a technique for electromagnetic wave suppression and heat dissipation, in which more magnetic particles are filled in a base material to improve the heat dissipation effect and the electromagnetic wave suppression effect.
However, in the technique of Patent Document 1, since the magnetic powder easily aggregates, it is difficult to mix a large amount of the magnetic powder in the base material, and the effect of improving electromagnetic wave suppression is also limited. In addition, when a large amount of magnetic powder is mixed, the tackiness when the composition is used as a sheet is lowered, so that further improvement has been desired for the adhesion to the heat source and the heat radiating member. Moreover, further improvement has been desired for the thermal conductivity when the composition is used as a sheet.

JP 2010-183033 A

The present invention has been made in view of such circumstances, and provides an electromagnetic wave suppressing heat conductive sheet having high adhesion to a heat source and a heat radiating member, excellent in heat conductivity and electromagnetic wave suppressing effect, and a method for manufacturing the same. With the goal. Another object of the present invention is to provide a semiconductor device having such heat dissipation and electromagnetic wave suppression effects using such an electromagnetic wave suppression heat conductive sheet.

As a result of intensive studies to solve the above problems, the inventors of the present invention have found that the electromagnetically conductive heat conductive sheet has a heat conductive filler oriented in a direction substantially perpendicular to the sheet surface, and heat conductivity. By configuring the filler to be oriented in a direction substantially parallel to the sheet surface, the thermally conductive filler oriented in a direction substantially perpendicular to the sheet surface improves the thermal conductivity from the heat source to the heat dissipation member. As a result of contributing to the improvement of the electromagnetic wave suppression effect, the present inventors have found that both the thermal conductivity and the electromagnetic wave suppression effect can be achieved at a high level. Moreover, in the heat conductive filler of this invention, since it did not contain a lot of magnetic powder for the improvement of the electromagnetic wave suppression effect, it discovered that the adhesiveness with respect to a heat source or a heat radiating member did not fall.

The present invention has been made based on the above findings, and the gist thereof is as follows.
(1) An electromagnetic wave suppressing heat conductive sheet containing a binder resin and a fibrous heat conductive filler, wherein the heat conductive filler is oriented in a direction substantially perpendicular to the sheet surface. An electromagnetic wave-suppressing heat conductive sheet, wherein the vertical alignment body and a horizontal alignment body in which the heat conductive filler is aligned in a direction substantially parallel to the sheet surface are connected in the same plane.
By the said structure, the high adhesiveness with respect to a heat source or a heat radiating member and the outstanding thermal conductivity and electromagnetic wave suppression effect are realizable.
(2) The electromagnetic wave suppression heat conductive sheet according to (1), wherein the plurality of vertical alignment bodies and the plurality of horizontal alignment bodies are alternately connected.
(3) The electromagnetic wave suppression heat conductive sheet according to (1) or (2), wherein the fibrous heat conductive filler is carbon fiber.
(4) The electromagnetic wave suppression heat conduction sheet according to any one of (1) to (3), wherein at least one of the vertical alignment body and the horizontal alignment body further includes a filler. .
(5) The electromagnetic wave suppression heat according to any one of (1) to (4) above, wherein at least one of the vertical alignment body and the horizontal alignment body further includes magnetic metal powder. Conductive sheet.
(6) The electromagnetic wave suppression heat conductive sheet according to (5), wherein at least the horizontal alignment body further includes magnetic metal powder.
(7) The electromagnetic wave-suppressing heat conductive sheet according to any one of (1) to (6) above, wherein both the vertical alignment body and the horizontal alignment body have adhesiveness on the surface.
(8) A step of preparing a composition for a sheet containing a binder resin and a fibrous thermal conductive filler, a step of orienting the fibrous thermal conductive filler, and the fibrous thermal conductivity In a state where the orientation of the filler is maintained, the binder resin is cured to produce an orientation body block, and the orientation body block is cut into a plurality along the orientation direction of the thermally conductive filler, A part of the cut alignment body block is rotated by 90 ° on the cut surface, and then the cut blocks are pressure-bonded together to produce a pressure-bonded alignment body block, and the pressure-bonded alignment body block Cutting a plurality of pieces along a direction orthogonal to the cutting direction of the oriented body block to obtain an electromagnetic wave suppressing heat conductive sheet, and a method for producing an electromagnetic wave suppressing heat conductive sheet.
By the said structure, the electromagnetic wave suppression heat conductive sheet which has the high adhesiveness with respect to a heat source and a heat radiating member, and the outstanding heat conductivity and electromagnetic wave suppression effect can be obtained.
(9) A semiconductor device comprising a heat source, a heat radiating member, and an electromagnetic wave suppressing heat conductive sheet sandwiched between the heat source and the heat radiating member, wherein the electromagnetic wave suppressing heat conductive sheet is the above (1) to ( 7) A semiconductor device, wherein the semiconductor device is an electromagnetic wave-suppressing heat conductive sheet.
With the above configuration, excellent heat dissipation and electromagnetic wave suppression can be realized.

According to the present invention, it is possible to provide an electromagnetic wave suppressing heat conductive sheet having high adhesion to a heat source and a heat radiating member and excellent in thermal conductivity and an electromagnetic wave suppressing effect, and a manufacturing method thereof. Moreover, it becomes possible to provide the semiconductor device which has heat dissipation and electromagnetic wave suppression effect using this electromagnetic wave suppression heat conductive sheet.

It is the figure which showed typically one Embodiment of the electromagnetic wave suppression heat conductive sheet of this invention, (a) is sectional drawing of the direction orthogonal to a sheet | seat surface, (b) is a top view of an electromagnetic wave suppression heat conductive sheet. It is. (A) And (b) is the top view which showed typically other embodiment of the electromagnetic wave suppression heat conductive sheet of this invention. (A)-(e) is a flowchart for demonstrating one Embodiment of the manufacturing method of the electromagnetic wave suppression heat conductive sheet of this invention. (A) is the figure which showed typically one Embodiment of the semiconductor device of this invention, (b) is the figure which showed typically other Embodiment of the semiconductor device of this invention. It is a figure which shows the transmission attenuation amount according to the frequency obtained from the sample of each Example and the comparative example.

Hereinafter, an example of an embodiment of the present invention will be specifically described.
<Electromagnetic wave suppression heat conductive sheet>
First, the electromagnetic wave suppression heat conductive sheet of this invention is demonstrated using drawing. In addition, about the dimension of each structural member disclosed in the figure, the dimension different from an actual dimension is shown for convenience of explanation.
As shown in FIGS. 1A and 1B, the present invention is an electromagnetic wave suppressing heat conductive sheet 1 including a binder resin 11 and a fibrous heat conductive filler 12.
And the electromagnetic wave suppression heat conductive sheet 1 of this invention is as shown to Fig.1 (a). It is characterized in that the conductive filler 12 is connected in the same plane to a horizontal alignment body 10b in which the conductive filler 12 is aligned in a direction substantially parallel to the sheet surface.

Since the vertical alignment body 10a and the horizontal alignment body 10b both contain the binder resin 11 and the fibrous heat conductive filler 12, they have good heat conductivity and electromagnetic wave suppression effect. And in particular, with respect to the vertical alignment body 10a, the thermally conductive filler 12 is oriented in a direction substantially perpendicular to the sheet surface, and in the thickness direction of the sheet (the direction connecting the heat generating part and the heat radiating member). It is more excellent in thermal conductivity, and for the horizontal alignment body 10b, the thermal conductive filler 12 is oriented in a substantially parallel direction with respect to the sheet surface, and works as an obstacle to electromagnetic noise, so that the electromagnetic wave suppression effect It has the characteristic of being superior. Therefore, by combining the vertical alignment body 10a and the horizontal alignment body 10b into a single sheet, the thermal conductivity and the electromagnetic wave suppression effect are higher than the conventional heat conductive sheet having the electromagnetic wave suppression effect. Can be compatible at each level.

(Binder resin)
The electromagnetic wave suppression heat conductive sheet 1 of this invention contains the binder resin 11 as shown to Fig.1 (a) and (b).
The binder resin 11 is a component that becomes a base material of the electromagnetic wave suppression heat conductive sheet 1 of the present invention. The type is not particularly limited, and a known binder resin can be appropriately selected. For example, one of the binder resins is a thermosetting resin.

Examples of the thermosetting resin include crosslinkable rubber, epoxy resin, polyimide resin, bismaleimide resin, benzocyclobutene resin, phenol resin, unsaturated polyester, diallyl phthalate resin, silicone, polyurethane, polyimide silicone, and thermosetting type. Examples include polyphenylene ether and thermosetting modified polyphenylene ether. These may be used individually by 1 type and may use 2 or more types together.

Examples of the crosslinkable rubber include natural rubber, butadiene rubber, isoprene rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene propylene rubber, chlorinated polyethylene, chlorosulfonated polyethylene, butyl rubber, halogenated butyl rubber, Examples thereof include fluorine rubber, urethane rubber, acrylic rubber, polyisobutylene rubber, and silicone rubber. These may be used individually by 1 type and may use 2 or more types together.

Of the thermosetting resins described above, it is preferable to use silicone from the viewpoints of excellent moldability and weather resistance, and adhesion and followability to electronic components.

There is no restriction | limiting in particular as said silicone, According to the objective, the kind of silicone can be selected suitably.
From the viewpoint of obtaining the above-described molding processability, weather resistance, adhesion, and the like, the silicone is preferably a silicone composed of a liquid silicone gel main ingredient and a curing agent. Examples of such silicone include addition reaction type liquid silicone, heat vulcanization type millable type silicone using peroxide for vulcanization, and the like. Among these, it is more preferable to use an addition reaction type liquid silicone as a heat radiating member of an electronic device because adhesion between the heat generating surface of the electronic component and the heat sink surface is required.

As the addition reaction type liquid silicone, it is more preferable to use a two-component addition reaction type silicone using a polyorganosiloxane having a vinyl group as a main ingredient and a polyorganosiloxane having a Si—H group as a curing agent.
Note that, in the combination of the main agent and the curing agent of the liquid silicone gel, the mixing ratio of the main agent and the curing agent is preferably, as a mass ratio, main agent: curing agent = 35: 65 to 65:35. .

Further, the content of the binder resin in the electromagnetic wave suppressing heat conductive sheet of the present invention is not particularly limited and can be appropriately selected according to the purpose. For example, from the viewpoint of ensuring sheet formability, sheet adhesion, and the like, it is preferably about 20% to 50% by volume of the electromagnetic wave suppressing heat conductive sheet, and is preferably 30% to 40% by volume. It is more preferable.

(Thermal conductive filler)
As shown in FIGS. 1A and 1B, the electromagnetic wave suppression heat conductive sheet 1 of the present invention further includes a fibrous heat conductive filler 12 in the binder resin 11. The thermally conductive filler 12 is a component for improving the thermal conductivity of the sheet. About the kind of heat conductive filler, it is not specifically limited except being a fibrous heat conductive filler, A well-known heat conductive filler can be selected suitably.

The “fibrous” of the fibrous thermal conductive filler in the present invention means a shape having a high aspect ratio (approximately 6 or more). Therefore, in the present invention, not only thermal conductive fillers such as fibers and rods, but also granular fillers having a high aspect ratio, flaky thermal conductive fillers, and the like are fibrous thermal conductive fillers. include.

Here, the type of the fibrous thermally conductive filler is not particularly limited as long as it is a fibrous and highly thermally conductive material. For example, metals such as silver, copper, and aluminum, alumina, and nitriding Examples thereof include ceramics such as aluminum, silicon carbide, and graphite, and carbon fibers.
Among these fibrous thermal conductive fillers, it is preferable to use carbon fibers from the viewpoint of obtaining higher thermal conductivity.
In addition, about the said heat conductive filler, you may use individually by 1 type, and may mix and use 2 or more types. In addition, when two or more kinds of thermally conductive fillers are used, both of them may be fibrous thermal conductive fillers, or the thermal conductivity of a different shape from the fibrous thermal conductive fillers. You may mix and use a filler.

The type of the carbon fiber is not particularly limited and can be appropriately selected depending on the purpose. For example, pitch, PAN, graphitized PBO fiber, synthesized by arc discharge method, laser evaporation method, CVD method (chemical vapor deposition method), CCVD method (catalytic chemical vapor deposition method), etc. Can be used. Among these, carbon fibers obtained by graphitizing PBO fibers and pitch-based carbon fibers are more preferable because high thermal conductivity can be obtained.

Moreover, the carbon fiber can be used after partly or entirely treating the carbon fiber, if necessary. Examples of the surface treatment include oxidation treatment, nitriding treatment, nitration, sulfonation, or attaching a metal, a metal compound, an organic compound, or the like to the surface of a functional group or carbon fiber introduced to the surface by these treatments. The process etc. which are combined are mentioned. Examples of the functional group include a hydroxyl group, a carboxyl group, a carbonyl group, a nitro group, and an amino group.

Further, the average fiber length (average major axis length) of the fibrous thermal conductive filler is not particularly limited and may be appropriately selected. From the viewpoint of surely obtaining high thermal conductivity, 50 μm to It is preferably in the range of 300 μm, more preferably in the range of 75 μm to 275 μm, and particularly preferably in the range of 90 μm to 250 μm. When the average fiber length is less than 50 μm, high thermal conductivity may not be obtained. On the other hand, when the average fiber length is longer than 300 μm, dispersibility in the electromagnetic wave suppression heat conductive sheet decreases. There is a risk that sufficient thermal conductivity cannot be obtained.
Furthermore, the average fiber diameter (average minor axis length) of the fibrous thermal conductive filler is not particularly limited and can be appropriately selected. However, 4 μm can be surely obtained from high thermal conductivity. It is preferably in the range of ˜20 μm, more preferably in the range of 5 μm to 14 μm.
The aspect ratio (average major axis length / average minor axis length) of the fibrous thermal conductive filler is 6 or more from the viewpoint of surely obtaining high thermal conductivity. 50 is preferred. Even when the aspect ratio is small, an effect of improving thermal conductivity and the like is observed, but a large characteristic improvement effect cannot be obtained due to a decrease in orientation, and therefore the aspect ratio is set to 6 or more. On the other hand, when it exceeds 50, the dispersibility in the electromagnetic wave suppression heat conductive sheet is lowered, so that there is a possibility that sufficient heat conductivity cannot be obtained.
Here, the average major axis length and the average minor axis length of the fibrous thermal conductive filler are measured by, for example, a microscope, a scanning electron microscope (SEM), etc., and an average is calculated from a plurality of samples. can do.

Further, the content of the fibrous heat conductive filler in the electromagnetic wave suppressing heat conductive sheet is not particularly limited and may be appropriately selected depending on the intended purpose, but is 4 vol% to 40 vol%. It is preferably 5% by volume to 30% by volume, more preferably 6% by volume to 20% by volume. If the content is less than 4% by volume, it may be difficult to obtain a sufficiently low thermal resistance. If the content exceeds 40% by volume, the moldability of the electromagnetic wave suppressing heat conductive sheet and the fibrous shape may be reduced. There is a risk of affecting the orientation of the thermally conductive filler.

In the electromagnetic wave suppression heat conductive sheet 1 of the present invention, as described above, the thermally conductive filler 12 is aligned in a substantially vertical direction with respect to the sheet surface, and the heat conductive filler 12 is a sheet. The horizontal alignment body 10b orientated in the substantially parallel direction with respect to the surface is connected in the same plane (FIG. 1 (b)). This is to obtain excellent thermal conductivity and electromagnetic wave suppression effect.
Here, the direction substantially perpendicular to the sheet surface is a direction substantially the same as the vertical direction T with respect to the extending direction S of the sheet surface, and a direction substantially parallel to the sheet surface. Is a direction along the extending direction S of the sheet surface. However, since the orientation direction of the fibrous thermal conductive filler 12 has some orientation variation during production, in the present invention, the sheet surface extending direction S or the direction T perpendicular to the sheet surface or Therefore, if the deviations are within ± 20 °, it can be said that they are substantially horizontal and substantially perpendicular to the sheet surface. In addition, from the viewpoint of obtaining higher thermal conductivity and electromagnetic wave suppression effect, it is preferable that the deviation is within ± 10 ° from the extending direction S and the direction T perpendicular to the sheet surface, and the deviation is within ± 5 °. Is more preferable.

In addition, about the method of adjusting the orientation direction of the said fibrous heat conductive filler 12, although demonstrated in detail in description of the manufacturing method of the electromagnetic wave suppression heat conductive sheet of this invention, for example, the said electromagnetic wave suppression heat conduction An orientation direction can be adjusted by adjusting a cut-out angle in a state in which a molded body for a sheet as a base of the sheet is produced and the fibrous thermal conductive filler is oriented.

(Filler)
The electromagnetic wave suppression heat conductive sheet of the present invention preferably further contains a filler in addition to the binder resin and the fibrous heat conductive fiber described above. This is because the heat conductivity of the electromagnetic wave suppression heat conductive sheet can be further increased and the strength of the sheet can be improved.
The filler is not particularly limited with respect to shape, material, average particle diameter, and the like, and can be appropriately selected according to the purpose. Examples of the shape include a spherical shape, an elliptical spherical shape, a lump shape, a granular shape, a flat shape, and a needle shape. Among these, spherical and elliptical shapes are preferable from the viewpoint of filling properties, and spherical shapes are particularly preferable.

Examples of the filler material include aluminum nitride (aluminum nitride: AlN), silica, alumina (aluminum oxide), boron nitride, titania, glass, zinc oxide, silicon carbide, silicon (silicon), silicon oxide, aluminum oxide, Metal particles etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, alumina, boron nitride, aluminum nitride, zinc oxide, and silica are preferable, and alumina and aluminum nitride are particularly preferable from the viewpoint of thermal conductivity.

Also, the filler can be a surface-treated one. When the filler is treated with a coupling agent as the surface treatment, the dispersibility of the filler is improved and the flexibility of the electromagnetic wave suppressing heat conductive sheet is improved.

About the average particle diameter of the said filler, it can select suitably according to the kind etc. of an inorganic substance.
When the filler is alumina, the average particle size is preferably 1 μm to 10 μm, more preferably 1 μm to 5 μm, and particularly preferably 4 μm to 5 μm. When the average particle size is less than 1 μm, the viscosity increases and mixing may be difficult. On the other hand, if the average particle size exceeds 10 μm, the heat resistance of the electromagnetic wave suppression heat conductive sheet may increase.
Further, when the filler is aluminum nitride, the average particle diameter is preferably 0.3 μm to 6.0 μm, more preferably 0.3 μm to 2.0 μm, and particularly preferably 0.5 μm to 1.5 μm. . If the average particle size is less than 0.3 μm, the viscosity may increase and mixing may be difficult, and if it exceeds 6.0 μm, the heat resistance of the electromagnetic wave suppression heat conductive sheet may increase.
In addition, about the average particle diameter of the said filler, it can measure with a particle size distribution meter and a scanning electron microscope (SEM), for example.

(Magnetic metal powder)
As shown in FIGS. 1 (a) and 1 (b), the electromagnetic wave suppressing heat conductive sheet 1 of the present invention is in addition to the binder resin 11, fibrous heat conductive fibers 12 and filler (not shown) described above, It is preferable that the magnetic metal powder 13 is further included. By including the magnetic metal powder 13, the electromagnetic wave absorbability of the electromagnetic wave suppressing heat conductive sheet 1 can be improved.

The type of the magnetic metal powder is not particularly limited except that it has electromagnetic wave absorptivity, and a known magnetic metal powder can be appropriately selected. For example, amorphous metal powder or crystalline metal powder can be used. Examples of amorphous metal powders include Fe-Si-B-Cr, Fe-Si-B, Co-Si-B, Co-Zr, Co-Nb, and Co-Ta. Examples of the crystalline metal powder include pure iron, Fe-based, Co-based, Ni-based, Fe-Ni-based, Fe-Co-based, Fe-Al-based, Fe-Si-based, and Fe-Si-Al-based. Fe-Ni-Si-Al-based materials and the like. Further, the crystalline metal powder is a microcrystalline metal obtained by adding a small amount of N (nitrogen), C (carbon), O (oxygen), B (boron), etc. to the crystalline metal powder. Powder may be used.
In addition, about the said magnetic metal powder, you may use what mixed the thing from which a material differs, or the thing from which an average particle diameter differs 2 or more types.

Moreover, about the said magnetic metal powder, it is preferable to adjust shapes, such as spherical shape and flat shape. For example, in order to increase the filling property, it is preferable to use a magnetic metal powder having a particle size of several μm to several tens of μm and a spherical shape. Such a magnetic metal powder can be produced by, for example, an atomizing method or a method of thermally decomposing metal carbonyl. The atomizing method has the advantage that a spherical powder is easy to make. The molten metal flows out from the nozzle, and a jet stream of air, water, inert gas, etc. is sprayed on the molten metal and solidified as droplets. It is a method of making a powder. When the amorphous magnetic metal powder is produced by the atomizing method, the cooling rate is preferably about 10 ⁶ (K / s) in order to prevent the molten metal from crystallizing.

When the amorphous alloy powder is manufactured by the atomization method described above, the surface of the amorphous alloy powder can be made smooth. Thus, when amorphous alloy powder with few surface unevenness | corrugations and a small specific surface area is used as magnetic metal powder, a filling property can be improved with respect to binder resin. Furthermore, the filling property can be further improved by performing the coupling treatment.

In addition, about the said magnetic metal powder, it can contain in at least one of the vertical alignment body and the horizontal alignment body which comprise the electromagnetic wave suppression heat conductive sheet of this invention. However, from the viewpoint of further enhancing the electromagnetic wave suppressing effect of the electromagnetic wave suppressing heat conductive sheet, it is more preferable to include at least the horizontal alignment body, and further preferable to include both the vertical alignment body and the horizontal alignment body.

Further, the content of the magnetic metal powder in the electromagnetic wave suppression heat conductive sheet of the present invention is not particularly limited and can be appropriately selected according to the purpose, but the sheet adhesion while ensuring good electromagnetic wave shielding properties. From the viewpoint of improving the property, the content is preferably about 35% to 75% by volume, more preferably 40% to 65% by volume of the electromagnetic wave suppressing heat conductive sheet.

(Other ingredients)
In addition to the binder resin, the fibrous heat conductive filler, the filler, and the magnetic metal powder, the electromagnetic wave suppressing heat conductive sheet of the present invention can appropriately include other components depending on the purpose. is there.
Examples of the other components include thixotropic agents, dispersants, curing accelerators, retarders, tackifiers, plasticizers, flame retardants, antioxidants, stabilizers, colorants, and the like.

Moreover, about the electromagnetic wave suppression heat conductive sheet of this invention, as shown to Fig.1 (a), the said vertical alignment body 10a and the said horizontal alignment body 10b should just be connected in the same plane, and the said perpendicular | vertical body is sufficient. There are no particular limitations on the size, shape, number, etc. of the alignment body 10a and the horizontal alignment body 10b.

For example, as shown in FIGS. 1 (a) and 1 (b), a plurality of the vertical alignment bodies 10a and a plurality of the horizontal alignment bodies 10b can be connected in a form having regularity alternately. However, they can be connected with random regularity. As another embodiment, as shown in FIG. 2 (a), the vertical alignment body 10a may be connected so as to surround the horizontal alignment body 10b, as shown in FIG. 2 (b). The vertical alignment bodies 10a and the horizontal alignment bodies 10b can be connected to each other at diagonal positions.
However, the electromagnetic wave suppressing heat conductive sheet can be produced relatively easily, and the obtained electromagnetic wave suppressing heat conductive sheet is excellent in thermal conductivity and electromagnetic wave suppressing effect, as shown in FIGS. 1 (a) and (b). As described above, the plurality of vertical alignment bodies 10a and the plurality of horizontal alignment bodies 10b are preferably connected alternately.

Also, the numbers of the vertical alignment bodies 10a and the horizontal alignment bodies 10b constituting the electromagnetic wave suppressing heat conductive sheet of the present invention are not particularly limited, and can be appropriately changed according to the size of the sheet. For example, it is preferable that the number of the vertical alignment bodies 10a and the horizontal alignment bodies 10b is two or more from the viewpoint that the thermal conductivity and electromagnetic wave suppression effect of the electromagnetic wave suppression heat conductive sheet can be realized at a higher level. More preferably, the number is 3 or more, and still more preferably 5 or more. When the position of the heat generating portion of the semiconductor element is specified in advance and the vertical alignment body 10a can be disposed on the heat generation portion, the number of the vertical alignment bodies 10a and the horizontal alignment bodies 10b is small. However, when the position of the heat generating portion is not clear, it is possible to ensure good thermal conductivity by providing a certain number of vertical alignment bodies 10a.

Furthermore, it is preferable that both the vertical alignment body and the horizontal alignment body have adhesiveness on the surface. This is because each of the vertical alignment body and the horizontal alignment body has adhesiveness on the surface, thereby improving the connection strength when the sheets are connected to form an electromagnetic wave suppressing heat conductive sheet. Furthermore, since the surface of the electromagnetic wave suppression heat conduction sheet of the present invention has adhesiveness, the adhesion between the electromagnetic wave suppression heat conduction sheet of the present invention and the heat / electromagnetic wave generation source, and the adhesion between the heat radiating member are improved. As a result of being able to improve and temporarily sticking the electromagnetic wave suppressing heat conductive sheet, it is possible to effectively suppress the occurrence of displacement when the heat / electromagnetic wave generating source or the heat radiating member is pressed.
Here, although the size of the adhesiveness of the vertical alignment body and the horizontal alignment body surface is not particularly limited, from the point that it is possible to further improve the adhesion with the heat / electromagnetic wave generation source and the heat dissipation member, The 90 ° peel adhesive strength (JIS Z 0237: 2009) is preferably 0.1 N / cm or more.
In addition, the method for imparting adhesiveness to the surfaces of the vertical alignment body and the horizontal alignment body is not particularly limited, and the binder resin itself constituting the vertical alignment body and the horizontal alignment body is provided with adhesiveness. It is also possible to form a highly tacky tack layer on the surfaces of the vertical alignment body and the horizontal alignment body. Examples of the tack layer include an adhesive layer.

The volume ratio between the vertical alignment body and the horizontal alignment body constituting the electromagnetic wave suppressing heat conductive sheet of the present invention is not particularly limited. For example, from the viewpoint of achieving both high thermal conductivity and electromagnetic wave suppression effects at a high level, the volume ratio of the vertical alignment body to the horizontal alignment body is preferably 1: 9 to 9: 1, and 3: 7 to 7: 3 is more preferable.

Further, the thickness of the electromagnetic wave suppression heat conductive sheet of the present invention is not particularly limited, and can be appropriately changed depending on the place where the sheet is used. For example, in consideration of the adhesion and strength balance of the electromagnetic wave suppressing heat conductive sheet, the thickness can be in the range of 0.2 to 5 mm.
In addition, since the said vertical alignment body and the said horizontal alignment body connect and comprise the electromagnetic wave suppression heat conductive sheet of this invention, they have comparable thickness.

<Method for Producing Electromagnetic Wave Suppressing Thermal Conductive Sheet>
Next, the manufacturing method of the electromagnetic wave suppression heat conductive sheet of this invention is demonstrated using drawing. FIGS. 3 (a) to 3 (e) show a part of the flow of steps in an example of the method for producing an electromagnetic wave suppressing heat conductive sheet of the present invention.
The method for producing an electromagnetic wave suppressing heat conductive sheet of the present invention includes a binder resin 11 and a fibrous heat conductive filler 12 (including a magnetic metal powder 13, a filler, and other components as necessary). A step of preparing a sheet composition (sheet composition preparation step);
A step of orienting the fibrous thermal conductive filler 12 with respect to the sheet surface (filler orientation step);
As shown in FIG. 3 (a), the binder resin 11 is cured in a state where the orientation of the fibrous thermal conductive filler 12 is maintained (the orientation body block production step). Process), and
As shown in FIG. 3 (b), the oriented body block 20 is cut into a plurality along the orientation direction P of the thermally conductive filler, and the cut orientation is shown in FIG. 3 (c). After rotating part 21 ′ of the body block 21 by 90 ° on the cut surface, the cut blocks are pressure-bonded as shown in FIG. A process (crimp alignment body block manufacturing process),
As shown in FIG. 3 (e), the step of obtaining the electromagnetic wave suppressing heat conductive sheet 1 by cutting the pressure-bonded alignment body block 22 into a plurality along the direction Q perpendicular to the cutting direction of the alignment body block 20 (electromagnetic wave) Suppression heat conductive sheet manufacturing process),
It is characterized by including.
By passing through each said process, the electromagnetic wave suppression heat conductive sheet of this invention can be obtained. About the obtained electromagnetic wave suppression heat conductive sheet, as mentioned above, it is excellent in thermal conductivity and an electromagnetic wave suppression effect.

(Sheet composition preparation process)
The manufacturing method of the electromagnetic wave suppression heat conductive sheet of this invention includes the composition preparation process for sheets.
In the sheet composition preparation step, the above-described binder resin, fibrous thermal conductive filler and magnetic metal powder, and further, filler and / or other components are blended to prepare a sheet composition. The procedure for blending and preparing each component is not particularly limited. For example, a binder resin, a fibrous thermal conductive filler, a filler, a magnetic metal powder, and other components are added to the binder resin and mixed. By doing this, the composition for a sheet is prepared.

(Filler orientation process)
The manufacturing method of the electromagnetic wave suppression heat conductive sheet of this invention includes the composition preparation process for sheets.
The method for orienting the fibrous heat conductive filler is not particularly limited as long as it is a means capable of orienting in one direction.

Examples of a method for orienting the fibrous heat conductive filler in one direction include a method in which the sheet composition is extruded or pressed into a hollow mold under a high shear force. It is done. By this method, the fibrous thermally conductive filler can be oriented relatively easily. The orientation of the fibrous thermally conductive filler is preferably within ± 10 ° of the orientation direction.

Specific examples of the method for extruding or press-fitting the sheet composition into the hollow mold described above under a high shear force include an extrusion molding method and a mold molding method.
When extruding the sheet composition from a die in the extrusion molding method, or when press-fitting the thermally conductive resin composition into the mold in the mold molding method, the binder resin flows, and its flow direction The carbon fibers are oriented along. At this time, if a slit is attached to the tip of the die, the carbon fibers are more easily oriented.

(Oriented body block manufacturing process)
The manufacturing method of the electromagnetic wave suppression heat conductive sheet of this invention includes an orientation body block preparation process, as shown to Fig.3 (a).
Here, the alignment block 20 is produced by curing the binder resin 11 while maintaining the alignment state of the fibrous thermal conductive filler 12 performed in the filler alignment step described above. Is called.

The method and conditions for curing the binder resin 11 can be changed according to the type of the binder resin 11. For example, when the binder resin 11 is a thermosetting resin, the curing temperature in thermosetting can be adjusted. Further, when the thermosetting resin contains a main component of a liquid silicone gel and a curing agent, curing is preferably performed at a curing temperature of 80 ° C. to 120 ° C. The curing time in thermosetting is not particularly limited, but can be 1 hour to 10 hours.

The size and shape of the alignment body block 20 can be determined according to the required size of the electromagnetic wave suppressing heat conductive sheet 1. For example, a rectangular parallelepiped having a vertical size of 0.5 cm to 15 cm and a horizontal size of 0.5 cm to 15 cm can be mentioned. The length of the rectangular parallelepiped may be determined as necessary.

(Press-bonded alignment block manufacturing process)
As shown in FIGS. 3B to 3D, the method for producing an electromagnetic wave suppressing heat conductive sheet of the present invention includes a crimped alignment body block manufacturing step.
In the press-bonded alignment body block manufacturing step, the alignment body block 20 is cut into a plurality along the alignment direction P of the thermally conductive filler (FIG. 3B). Thereafter, a part 21 ′ of the plurality of cut alignment body blocks 21 is rotated by 90 ° on the cut surface (FIG. 3C). Then, the pressure-bonded alignment body block 22 is obtained by pressure-bonding the cut blocks 21 and 21 ′ (FIG. 3D).
The obtained pressure-bonded alignment body block 22 has the thermally conductive filler 12 in two orthogonal orientation directions because a part 21 ′ of the cut alignment body block is rotated 90 ° on the cut surface. Can do.

In addition, the method for cutting the alignment body block 20 is not particularly limited, and can be performed by a known method. For example, the cutting method using an ultrasonic cutter is mentioned.

In addition, the method for pressure-bonding the cut blocks 21 and 21 ′ is not particularly limited, and can be performed by a known method. For example, pressure bonding can be performed by using a pair of press devices each including a flat plate and a press head having a flat surface. Moreover, you may press using a pinch roll.

The pressure at the time of pressing is not particularly limited and can be appropriately selected according to the purpose. However, if it is too low, the thermal resistance tends to be the same as when not pressing, and if it is too high, the sheet is stretched. Due to the tendency, the pressure range is preferably 0.1 MPa to 100 MPa, and more preferably 0.5 MPa to 95 MPa.

(Electromagnetic wave suppression heat conduction sheet manufacturing process)
The manufacturing method of the electromagnetic wave suppression heat conductive sheet of this invention includes the electromagnetic wave suppression heat conductive sheet preparation process, as shown in FIG.3 (e).
In the electromagnetic wave suppressing thermal conductive sheet manufacturing step, the obtained crimped alignment block 22 is obtained by a direction Q orthogonal to the cutting direction of the alignment block 20 (direction along the alignment direction P of the thermally conductive filler 12). A plurality of pieces are cut along (FIG. 3E).
The electromagnetic wave suppression heat conductive sheet of this invention is obtained by cut | disconnecting the crimping | bonding alignment body block 22. FIG. About the obtained electromagnetic wave suppression heat conductive sheet, the said heat conductive filler 12 orientated in the substantially perpendicular | vertical direction with respect to the sheet | seat surface, and the vertical alignment body 10a, and the said heat conductive filler are substantially parallel to a sheet | seat surface. The horizontal alignment bodies 10b oriented in the direction are connected in the same plane.

In addition, the method for cutting the pressure-bonded alignment body block 22 is not particularly limited, and can be performed by a known method. For example, the cutting method using an ultrasonic cutter is mentioned.

<Semiconductor device>
Next, the semiconductor device of the present invention will be described.
The semiconductor device of the present invention is a semiconductor device including a heat source, a heat radiating member, and an electromagnetic wave suppressing heat conductive sheet sandwiched between the heat source and the heat radiating member, wherein the electromagnetic wave suppressing heat conductive sheet is described above. It is an electromagnetic wave suppression heat conductive sheet of the present invention.
By using the electromagnetic wave suppression heat conductive sheet of the present invention, the obtained semiconductor device is excellent in electromagnetic wave suppression effect while having high heat dissipation.

Here, the heat source is not particularly limited as long as it generates heat in the semiconductor device. For example, an electronic part etc. are mentioned, As this electronic part, CPU, MPU, a graphic arithmetic element, an image sensor etc. are mentioned.

The heat radiating member conducts heat generated from the heat source and dissipates it to the outside. For example, a radiator, a cooler, a heat sink, a heat spreader, a die pad, a printed board, a cooling fan, a Peltier element, a heat pipe, a metal cover, a housing, and the like can be given.

An example of the semiconductor device of the present invention will be described with reference to FIGS.
FIG. 4A is a schematic cross-sectional view showing an example of the semiconductor device of the present invention. The semiconductor device includes an electromagnetic wave suppression heat conductive sheet 1, a heat spreader 2, an electronic component 3, a heat sink 5, and a wiring substrate 6.

The electromagnetic wave suppression heat conduction sheet 1 absorbs unnecessary electromagnetic waves generated in the electronic component 3 and electromagnetic waves radiated from other components, and transfers heat generated by the electronic component 3, as shown in FIG. 2, the heat spreader 2 is fixed to the main surface 2 a facing the electronic component 3, and is sandwiched between the electronic component 3 and the heat spreader 2. Further, the electromagnetic wave suppressing heat conductive sheet 1 is sandwiched between the heat spreader 2 and the heat sink 5.

The heat spreader 2 is formed in, for example, a rectangular plate shape, and has a main surface 2a facing the electronic component 3 and a side wall 2b erected along the outer periphery of the main surface 2a. The heat spreader 2 is provided with the electromagnetic wave suppressing heat conductive sheet 1 on the main surface 2a surrounded by the side wall 2b, and the heat sink 5 is provided on the other surface 2c opposite to the main surface 2a via the electromagnetic wave suppressing heat conductive sheet 1. It is done. The heat spreader 2 has a higher thermal conductivity, so that the thermal resistance is reduced and the heat of the electronic component 3 such as a semiconductor element is efficiently absorbed. Therefore, the heat spreader 2 is formed using, for example, copper or aluminum having good thermal conductivity. be able to.

The electronic component 3 is a semiconductor package such as BGA, for example, and is mounted on the wiring board 6. Further, the heat spreader 2 also has the front end surface of the side wall 2b mounted on the wiring board 6, and thereby surrounds the electronic component 3 at a predetermined distance by the side wall 2b.

Then, the electromagnetic wave suppressing heat conductive sheet 1 is adhered to the main surface 2 a of the heat spreader 2, so that the heat generated by the electronic component 3 is absorbed and radiated from the heat sink 5. Adhesion of the heat spreader 2 and the electromagnetic wave suppression heat conductive sheet 1 can be performed by the adhesive force of the electromagnetic wave suppression heat conductive sheet 1 itself.

FIG. 4B is a schematic cross-sectional view showing another example of the semiconductor device of the present invention.
The semiconductor device includes an electromagnetic wave suppression heat conductive sheet 1, a heat spreader 2, an electronic component 3, a heat sink 5, and a wiring substrate 6.

The electromagnetic wave suppressing heat conductive sheet 1 absorbs unnecessary electromagnetic waves generated in the electronic component 3 and electromagnetic waves radiated from other components, and dissipates heat generated by the electronic component 3, as shown in FIG. As shown, the electronic component 3 is fixed to the upper surface 3 a and is sandwiched between the electronic component 3 and the heat spreader 2.

Next, the present invention will be specifically described based on examples. However, the present invention is not limited to the following examples.

Example 1
Under the conditions shown below, heat conduction sheet models (Examples and Comparative Examples 1 and 2) used for analysis by a three-dimensional electromagnetic field simulator were prepared.
In the model of the embodiment, two-component addition reaction type liquid silicone is used as a resin binder, alumina powder having an average particle diameter of 5 μm is used as a filler, and pitch-based carbon fiber having an average fiber length of 200 μm is used as a fibrous thermal conductive filler. (“Thermal Conductive Fiber” manufactured by Nippon Graphite Fiber Co., Ltd.) is used so that the volume ratio of two-component addition-reaction type liquid silicone: alumina powder: pitch-based carbon fiber = 35 vol%: 53 vol%: 12 vol% Dispersed 1 mm thick sheets were used as vertical alignment bodies and horizontal alignment bodies.
And in an Example, as shown in FIG. 1 (a) and (b), it is the electromagnetic wave suppression heat conduction which made eight vertical alignment bodies 10a and seven horizontal alignment bodies 10b connect alternately. Used as a sheet sample. The widths of the vertical alignment body 10a and the horizontal alignment body 10b are both 2 mm.

About the model of the comparative example 1, the sheet | seat which consists only of the vertical alignment body mentioned above was used.
About the model of the comparative example 2, the sheet | seat which consists only of the horizontal alignment body mentioned above was used.

(Evaluation)
・ Measurement of transmission attenuation The transmission attenuation (dB) of each model was derived by analysis simulating the inter-decoupling method described in IEC62333-2. Specifically, using a three-dimensional electromagnetic field simulator HFSS (Ansys), the power transmission side probe and the power reception side probe are modeled, a pair of loop antennas are arranged, and a heat conduction sheet is arranged between the antennas as a test sample. Thus, the transmission characteristic S21 from one antenna to the other antenna was comparatively evaluated. The value obtained by subtracting S21r (insertion loss when the test sample is not used) from S21m (insertion loss when the test sample is used) is expressed as transmission attenuation, the distance between the antennas is 6 mm, and the sample size is 30 x 30 x 1 mm.
FIG. 5 shows the transmission attenuation (dB) corresponding to the frequency (transmission frequency: 10 MHz to 10 GHz) for the models of Examples and Comparative Examples 1 and 2.

From FIG. 5, although the model of the example is somewhat inferior to the model of Comparative Example 2, the signal attenuation is larger in the frequency band of 4 GHz or more than the model of Comparative Example 1, and is about 5 dB at 8 GHz and about 3 dB at 10 GHz. It was found that the electromagnetic wave suppression effect was improved.

・ Measurement of thermal conductivity Each model was cut into a disk shape of φ20mm, and a load of 1.5kgf / cm ² was applied using a thermal conductivity measuring device (manufactured by Sony Corporation) in accordance with ASTM D 5470. Thus, the thermal conductivity was calculated.

From the results in Table 1, the model of Comparative Example 1 consisting only of the vertical alignment body is inferior in signal attenuation characteristics, but the thermal conductivity in the thickness direction is a high value of 9.2 W / mK in the measurement according to ASTM D5470. Indicated. On the other hand, in the model of Comparative Example 2 consisting only of the horizontal alignment body, although the signal attenuation characteristic is good, the heat conductivity is as low as 1.8 W / mK, and the heat conduction member that releases the heat from the electronic components with high heat output to the heat radiator As a result, it was found that the characteristics were insufficient.
With respect to the model of the example, it was found that a high thermal conductivity of about 5 W / mK can be obtained because half of the sheet is composed of a vertically aligned body.
Therefore, it was found that the model of the example was excellent in the balance between the thermal conductivity and the electromagnetic wave suppression effect as compared with the models of Comparative Examples 1 and 2.

(Example 2)
A sample of the electromagnetic wave suppressing heat conductive sheet was actually produced under the following conditions.
Two-component addition-reactive liquid silicone is used as the resin binder, alumina powder with an average particle size of 5 μm is used as the filler, and pitch-based carbon fibers with an average fiber length of 200 μm as the fibrous thermal conductive filler (“thermal conductive fibers”). A two-component addition reaction type liquid silicone: alumina powder: pitch-based carbon fiber = 35 vol%: 53 vol%: 12 vol% silicone composition dispersed using a graphite composition manufactured by Nippon Graphite Fiber Co., Ltd. Was extruded into a mold (hollow cylindrical shape) with an extruder to obtain a silicone molded body. A slit (discharge port shape: flat plate) is formed at the extrusion port of the extruder.
Thereafter, the obtained silicone molded body was heated in an oven at 100 ° C. for 1 hour to obtain an alignment body block 20. Then, the obtained oriented body block 20 was sliced and cut along the orientation direction of the carbon fiber with an ultrasonic cutter so that the thickness became 0.5 mm, and a cut block 21 was obtained. (Transmission frequency 20.5kHz, amplitude 50-70μm).
Next, the same oriented body block 20 was sliced and cut in a direction substantially perpendicular to the orientation direction of the fibrous filler with an ultrasonic cutter so that the thickness became 0.5 mm, to obtain a cut block 21 ′.
The cut block 21 and the cut block 21 ′ thus obtained were alternately stacked in 30 layers, and subjected to hot pressing (temperature, pressure, time) to produce a pressure-bonded alignment body block 22. Thereafter, the obtained pressure-bonded alignment body block 22 was cut with an ultrasonic cutter so as to have a thickness of 0.5 mm to obtain a sample of an electromagnetic wave suppressing heat conductive sheet.
The sample of the obtained electromagnetic wave suppressing heat conductive sheet had a square shape with a thickness of 0.5 mm, a length of 15 mm, and a width of 15 mm.

And when the cross section of the obtained sample of the electromagnetic wave suppression heat conductive sheet was observed with a microscope (“KH7700” manufactured by HiROX Co Ltd), the pitch carbon fiber was made of the electromagnetic wave suppression heat. It was oriented at 0 to 5 ° with respect to the thickness direction of the conductive sheet (orientated in a direction substantially perpendicular to the sheet surface). Further, in the layer corresponding to the horizontal alignment body, the pitch-based carbon fibers are aligned at 0 to 5 ° with respect to the sheet surface of the electromagnetic wave suppressing heat conductive sheet (orientated in a direction substantially parallel to the sheet surface). ), An electromagnetic wave suppressing heat conductive sheet according to the present invention was produced.

According to the present invention, it is possible to provide an electromagnetic wave suppressing heat conductive sheet having high adhesion to a heat source and a heat radiating member and excellent in thermal conductivity and an electromagnetic wave suppressing effect, and a manufacturing method thereof. Moreover, it becomes possible to provide the semiconductor device which has heat dissipation and electromagnetic wave suppression effect using this electromagnetic wave suppression heat conductive sheet.

DESCRIPTION OF SYMBOLS 1 Electromagnetic wave suppression heat conductive sheet 2 Heat spreader 2a Main surface 2b Side wall 2c Other surface on the opposite side to main surface 3 Electronic component 3a Upper surface 5 Heat sink 6 Wiring board 10a Vertical alignment body 10b Horizontal alignment body 11 Binder resin 12 Fibrous heat conduction Filler 13 Magnetic metal powder 20 Alignment block 21 Cut alignment block 22 Crimp alignment block S Sheet surface direction T Direction perpendicular to sheet surface P Orientation direction of fibrous thermally conductive filler Q Alignment Direction perpendicular to body block cutting direction

Claims (9)

1. An electromagnetic wave suppression heat conductive sheet containing a binder resin and a fibrous heat conductive filler,
   The electromagnetic wave suppressing heat conductive sheet includes a vertically aligned body in which the heat conductive filler is aligned in a direction substantially perpendicular to the sheet surface, and a horizontal direction in which the heat conductive filler is aligned in a direction substantially parallel to the sheet surface. An electromagnetic wave-suppressing heat conductive sheet, which is formed by connecting oriented bodies in the same plane.
2. The electromagnetic wave suppression heat conductive sheet according to claim 1, wherein a plurality of the vertical alignment bodies and a plurality of the horizontal alignment bodies are alternately connected.
3. 3. The electromagnetic wave suppressing heat conductive sheet according to claim 1 or 2, wherein the fibrous heat conductive filler is carbon fiber.
4. 4. The electromagnetic wave-suppressing heat conductive sheet according to claim 1, wherein at least one of the vertical alignment body and the horizontal alignment body further includes a filler.
5. 5. The electromagnetic wave suppressing heat conductive sheet according to claim 1, wherein at least one of the vertical alignment body and the horizontal alignment body further includes a magnetic metal powder.
6. 6. The electromagnetic wave suppressing heat conductive sheet according to claim 5, wherein at least the horizontal alignment body further includes a magnetic metal powder.
7. The electromagnetic wave-suppressing heat conductive sheet according to any one of claims 1 to 6, wherein the vertical alignment body and the horizontal alignment body both have adhesiveness on the surface.
8. Preparing a composition for a sheet comprising a binder resin and a fibrous thermal conductive filler;
   Orienting the fibrous thermally conductive filler in one direction;
   In a state where the orientation of the fibrous thermal conductive filler is maintained, the binder resin is cured to produce an oriented body block;
   The alignment body block is cut into a plurality along the alignment direction of the thermally conductive filler, and a part of the cut alignment body block is rotated by 90 ° on the cut surface and then cut. Crimping the blocks together to produce a crimped alignment block,
   Cutting the crimped alignment block into a plurality along a direction orthogonal to the cutting direction of the alignment block to obtain an electromagnetic wave suppressing heat conductive sheet;
   The manufacturing method of the electromagnetic wave suppression heat conductive sheet characterized by including this.
9. A semiconductor device comprising a heat source, a heat radiating member, and an electromagnetic wave suppressing heat conducting sheet sandwiched between the heat source and the heat radiating member,
   The semiconductor device according to claim 1, wherein the electromagnetic wave suppressing heat conductive sheet is the electromagnetic wave suppressing heat conductive sheet according to any one of claims 1 to 7.

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