JP2011178008A - Heat conductive sheet, method for manufacturing the same, and heat radiator using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat conductive sheet and a method for manufacturing the heat conductive sheet, having high heat conductivity and allowing performance such as a close contact property and adhesiveness to be easily added. <P>SOLUTION: The heat conductive sheet has a multilayer structure including a metallic foil layer and an organic polymer compound layer. The metallic foil layer is laminated in two or more layers in one direction with respect to the surface of the heat conductive sheet, and the organic polymer compound layer contains at least an organic polymer compound. The respective metallic foil layers are connected by the organic polymer compound layer, and the metallic foil layers are oriented in the thickness direction of the heat conductive sheet. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat conductive sheet, a manufacturing method thereof, and a heat dissipation device using the same.

  In recent years, the wiring density and the mounting density of electronic components in multilayer wiring boards and semiconductor packages have increased, and semiconductor elements have been highly integrated, and the amount of heat generated per unit area of such heating elements has increased. Therefore, a technique for improving the efficiency of heat dissipation from the heating element is desired.

  As a general method of heat dissipation, a heat conductive material such as a heat conductive grease or a heat conductive sheet is sandwiched and adhered between a heat generating body such as a semiconductor package and a heat radiating body made of aluminum or copper to heat the outside. A communication method is adopted. From the viewpoint of workability when assembling the heat dissipation device, the heat conductive sheet is excellent. For this reason, various developments for heat conductive sheets have been studied.

  For example, for the purpose of improving thermal conductivity, a thermally conductive composite composition in which an inorganic material such as metal foil, metal particles, and metal oxide is combined with an organic material such as an organic polymer compound and its molding process Goods have been proposed. Among such inorganic materials, conductive materials such as metal foils and metal particles have particularly high thermal conductivity, and various studies have been made in order to utilize the thermal conductivity.

In patent document 1, by using metal foil and a metal mesh for an intermediate | middle layer, the intensity | strength of a sheet | seat is raised and the handleability is improved, and the thermal conductivity of metal foil is utilized. Moreover, in patent document 2, the thermal conductivity of a sheet | seat is improved by disperse | distributing a metal particle in a sheet | seat. Further, in Patent Document 3, graphite, which is a conductive material, is used like a metal, and the thermal conductivity in the film thickness direction is improved by providing a graphite layer penetrating in the film thickness direction of the sheet.
However, previous studies have not fully utilized the high thermal conductivity of metals, and further studies are needed.

Japanese Patent Laid-Open No. 2002-234952 JP 2000-129215 A JP 2009-55021 A

  For example, in the heat conductive sheet disclosed in Patent Document 1, a resin composition is used in a portion other than the intermediate layer, the heat conductivity is hindered by the resin composition, and the high heat conductivity of the metal portion is increased. It is difficult to use it sufficiently.

  On the other hand, in the heat conductive sheet disclosed in Patent Document 2, since metal particles are used, certain heat conductivity can be ensured, but the filling amount of metal particles is limited from the viewpoint of sheet formability. Further, it becomes difficult to increase the thermal conductivity.

  Moreover, since the heat conductive sheet disclosed in Patent Document 3 has a graphite layer penetrating in the film thickness direction, the high heat conductivity of graphite can be fully utilized. However, graphite is inferior in thermal conductivity as compared with metals such as copper and silver, and concerns such as graphite powder falling off remain. Furthermore, a process for producing an expanded graphite sheet used for the graphite layer is required, and it is difficult to easily produce a heat conductive sheet.

As described above, various studies have been made for the thermal conductive sheet, but none of the methods is satisfactory from the viewpoint of effectively utilizing the high thermal conductivity of the conductive material.
An object of this invention is to provide the heat conductive sheet which fully utilized the high thermal conductivity of an electroconductive material in view of such a condition. It is another object of the present invention to provide a method for manufacturing such a heat conductive sheet easily and reliably, and to provide a heat dissipation device having a high heat dissipation capability using such a heat conductive sheet.

The present invention is as follows.
(1) In the heat conductive sheet having a multilayer structure including a metal foil layer and an organic polymer compound layer, the metal foil layer is laminated in two or more layers in one direction with respect to the surface of the heat conductive sheet. The organic polymer compound layer contains at least an organic polymer compound, the metal foil layers are bonded with the organic polymer compound layer, and the metal foil layer is in the thickness direction of the heat conductive sheet. A heat conductive sheet characterized by being oriented in the direction.
(2) The metal foil layer laminated in two or more layers in the one direction is oriented at an angle of 0 to 50 degrees with respect to the thickness direction of the sheet. Thermal conductive sheet.

(3) The heat conductive sheet according to (1) or (2) above, wherein the organic polymer compound is a poly (meth) acrylic acid ester polymer compound.
(4) The metal foil layer includes at least one of copper, aluminum, iron, stainless steel, gold, silver, nickel, palladium, chromium, molybdenum and alloys thereof (1) to (3) The heat conductive sheet as described in any one of these.

(5) A method for producing a heat conductive sheet having a multilayer structure including the metal foil layer and the organic polymer compound layer,
The metal foil layer and the organic polymer compound layer are alternately laminated to form a molded body having a multilayer structure, and the molded body is at an angle of 0 to 30 degrees with respect to a normal line extending from the main surface. And a step of slicing.
(6) A method for producing a heat conductive sheet having a multilayer structure including the metal foil layer and the organic polymer compound layer,
A step of winding a laminate of the metal foil layer and the organic polymer compound layer around the orientation direction of the metal foil layer to form a molded body having a multilayer structure; and And a step of slicing at an angle of 0 to 30 degrees with respect to the outgoing normal.
(7) A heat dissipation device having a structure in which the heat conductive sheet according to any one of (1) to (4) is interposed between a heating element and a heat dissipation element.

  The heat conductive sheet of the present invention has high heat conductivity, and it is possible to easily add performance such as adhesion and adhesion as needed, so that they can be used for heat dissipation near electric / electronic circuits, for example. By applying to the above, it is possible to realize efficient heat dissipation from the heat generating portion.

Moreover, according to the method for producing a heat conductive sheet of the present invention, compared with the conventional method, it is advantageous in terms of productivity, cost, energy efficiency, and certainty, and has both high heat conductivity and adhesion. It becomes possible to provide a heat conductive sheet.
Furthermore, according to the heat dissipation device of the present invention, complete and efficient heat dissipation can be realized.

Hereinafter, the present invention will be described in detail.
<Heat conduction sheet>
The heat conductive sheet of the present invention has a multilayer structure including a metal foil layer and an organic polymer compound layer, and the metal foil layer is laminated in two or more layers in one direction with respect to the surface of the heat conductive sheet. The organic polymer compound layer contains at least an organic polymer compound, and each of the metal foil layers is bonded by the organic polymer compound layer.
As a specific manufacturing method, a molded body obtained by laminating or winding two or more metal foil layers and organic polymer compound layers in one direction is cut perpendicularly or at an angle to the thickness direction. It is produced by doing. In addition, a metal foil layer is laminated | stacked by two or more layers so that it may become one direction with respect to the surface direction of the heat conductive sheet obtained. Details of the manufacturing method will be described later.

In the present invention, the metal foil layer is “oriented in the thickness direction of the heat conductive sheet” means that the metal foil layer is completely parallel to the thickness of the heat conductive sheet and completely perpendicular to the surface of the heat conductive sheet. It is not necessary that the metal foil layer be oriented in a range where it can be said that the metal foil layer is oriented in the thickness direction rather than the surface direction of the heat conductive sheet. Preferably, the metal foil is preferably oriented at an angle of 0 to 50 degrees with respect to the sheet thickness direction.
Specifically, the cross section in the thickness direction of each side cut into a regular octagon of the heat conduction sheet is observed using an SEM (scanning electron microscope) or an optical microscope. An angle inclined from the conductive sheet thickness direction to the plane direction (a complementary angle is adopted when exceeding 90 degrees) is measured, and the average value is in a range of 0 to 50 degrees.

Each layer will be described below.
<Metal foil layer>
The metal foil layer is made of, for example, a metal foil made of a metal such as copper, aluminum, iron, stainless steel, gold, silver, nickel, palladium, chromium, molybdenum, or an alloy containing at least one of these metals. As the metal foil layer, it is possible to use the metal foil having a plurality of holes formed by punching, the metal wire having a woven shape, a meshed metal mesh, or the like.
Although there is no restriction | limiting in the thickness of a metal foil layer, 1 micrometer-1000 micrometers in thickness are preferable from a viewpoint on handling. Furthermore, in order to increase the adhesion with the organic polymer compound layer, the surface is mechanically or chemically treated by chemical roughening, corona discharge, sanding, plating, aluminum alcoholate, aluminum chelate, silane coupling agent, etc. It may be what you did.

<Organic polymer compound layer>
The organic polymer compound layer of the heat conductive sheet according to the present invention is not particularly limited as long as it contains an organic polymer compound, but has an appropriate tack strength and is easy to handle in the form of a sheet. It preferably contains a (meth) acrylic acid ester polymer compound.
The poly (meth) acrylic acid ester polymer compound is a polymer obtained by polymerizing a (meth) acrylic acid ester and a reactive monomer, and a functional group-containing poly (meta) obtained by copolymerizing a functional monomer. ) Acrylic acid ester polymer compounds are preferred.
Examples of the functional monomer include glycidyl acrylate, glycidyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate and the like, and these can be used alone or in combination of two or more. The mixing ratio in the case of using a combination of functional monomers is determined in consideration of the glass transition temperature (hereinafter referred to as “Tg”) of the functional group-containing poly (meth) acrylate polymer compound. The Tg of the functional group-containing poly (meth) acrylate polymer compound is preferably 50 ° C. or lower. This is because if the Tg is 50 ° C. or lower, the tackiness of the organic polymer compound layer is appropriate, and there is no problem in handling properties (such as the resin becomes hard and the flexibility is lowered).

The weight average molecular weight of the poly (meth) acrylic acid ester polymer compound is preferably 100,000 or more, more preferably 300,000 to 3,000,000, particularly preferably 400,000 to 1,000,000. When the weight average molecular weight is 100,000 or more, the heat resistance is high, and the strength, flexibility, and tackiness when formed into a sheet are appropriate.
In the present invention, the weight average molecular weight is a value measured by gel permeation chromatography and converted using a standard polystyrene calibration curve.

Examples of the poly (meth) acrylic acid ester-based polymer compound used in the present invention include Nagase ChemteX Corporation, trade name: HTR-860P-3 (copolymers such as butyl acrylate and acrylonitrile, ethyl acrylate and acrylonitrile). Polymer) and the like.
There is no restriction | limiting in particular as a manufacturing method of a poly (meth) acrylic-ester type polymer compound, For example, polymerization methods, such as pearl polymerization and solution polymerization, can be used. Moreover, as a component constituting the organic polymer compound, in addition to the poly (meth) acrylate polymer compound, a high molecular weight component, a thermosetting component, a curing accelerator, a filler, a coupling agent, and the like may be included. .
Examples of the high molecular weight component include polyimide, (meth) acrylic resin, urethane resin, polyphenylene ether resin, polyetherimide resin, phenoxy resin, and modified polyphenylene ether resin, but are not limited thereto.

The organic polymer compound layer in the heat conductive sheet of the present invention contains a thermosetting component and can impart curability. Examples of the thermosetting component include an epoxy resin, a cyanate resin, a phenol resin, and a resin curing agent thereof, and an epoxy resin is preferable in terms of high heat resistance. Moreover, these resin can be used individually or in combination of 2 or more types.
It does not specifically limit as a resin hardening agent in a thermosetting component, The well-known hardening agent used normally can be used. Specific examples include amines, polyamides, acid anhydrides, polysulfides, boron trifluoride, bisphenols, phenol resins, and the like, and phenol novolac resins and bisphenol A are particularly excellent in terms of resistance to electric corrosion during moisture absorption. Phenol resins such as novolak resins and cresol novolak resins are preferred.

  The curing accelerator that is an optional component of the organic polymer compound layer is not particularly limited, and imidazoles, dicyandiamide derivatives, dicarboxylic acid dihydrazides, triphenylphosphine, and the like can be used. These can be used alone or in combination of two or more. The addition amount of the curing accelerator is preferably from 0.1 to 5 parts by mass, preferably from 0.2 to 3 parts per 100 parts by mass of the thermosetting component and the resin curing agent, in terms of both curability and storage stability. Part by mass is more preferable.

Further, the organic polymer compound layer of the heat conductive sheet of the present invention is provided with a metal filler, an inorganic filler for the purpose of improving the handleability, improving the heat conductivity, imparting conductivity, adjusting the melt viscosity and imparting thixotropic properties. A filler such as an organic filler can also be added.
There is no restriction | limiting in particular as a metal filler, For example, gold | metal | money, silver, copper, aluminum, iron, indium, tin etc. and those alloys etc. can be used.
The inorganic filler is not particularly limited. For example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, Examples thereof include boron nitride, crystalline silica, and amorphous silica, and the shape of the filler is not particularly limited.
The organic filler is not particularly limited, and examples thereof include epoxy resin powder, various polymer powders, rubber powder such as fine silicone rubber, and the like.

  These fillers can be used alone or in combination of two or more. Among these fillers, silver, copper, aluminum, aluminum oxide, aluminum nitride, boron nitride, crystalline silica, amorphous silica and the like are preferable for improving thermal conductivity. For the purpose of adjusting melt viscosity and imparting thixotropic properties, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, crystallinity Silica, amorphous silica and the like are preferable.

As for the usage-amount of the said filler, 1-2000 mass parts is preferable with respect to 100 mass parts of organic polymer compound layers. If the amount is less than 1 part by mass, the addition effect tends to be not obtained. If the amount exceeds 2000 parts by mass, the storage elastic modulus of the organic polymer compound layer increases, the adhesiveness decreases, the electrical properties decrease due to the remaining voids, etc. There is a tendency to cause problems.
In addition, various coupling agents can be added to the organic polymer compound layer of the heat conductive sheet of the present invention in order to improve interfacial bonding between different materials. Examples of the coupling agent include silane-based, titanium-based, aluminum-based, and the like. Among these, a silane-based coupling agent is preferable because of its high addition effect.

  In the present invention, the composition for forming the organic polymer compound layer is preferably dissolved or dispersed in a solvent and used as a varnish. In the production of the varnish when the filler is added, it is preferable to use a raking machine, a three-roll, a ball mill, a bead mill or the like in consideration of the dispersibility of the filler, and these can be used in combination. Moreover, the mixing time can be shortened by mixing the filler and the low molecular weight raw material in advance and then blending the high molecular weight raw material. Further, after the varnish is formed, the bubbles in the varnish can be removed by vacuum degassing or the like.

The solvent for varnishing is not particularly limited, but considering volatility at the time of production, for example, methanol, ethanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, methyl ethyl ketone, It is preferable to use a solvent having a relatively low boiling point such as acetone, methyl isobutyl ketone, toluene and xylene. For the purpose of improving the coating properties, for example, a solvent having a relatively high boiling point such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and cyclohexanone can be used. These solvents can be used alone or in combination of two or more.
In addition, although there is no restriction | limiting in the thickness of an organic polymer compound layer, 1-1000 micrometers in thickness are preferable from a viewpoint on handling.

<Protective film>
In the present invention, it is preferable to protect the outermost surface prior to the use of the heat conductive sheet from the viewpoint of maintaining the shape of the heat conductive sheet of the present invention and preventing foreign matter contamination. The outermost surface is protected by, for example, providing a protective film on the outermost surface when forming the heat conductive sheet.
Examples of the material for the protective film include resins such as polyethylene, polyester, polypropylene, polyethylene terephthalate, polyimide, polyetherimide, polyether naphthalate, and methylpentene film, and metals such as coated paper, coated cloth, and aluminum. These protective films may be a multilayer film composed of two or more kinds of films, and a film whose surface is treated with a release agent such as silicone or silica is preferably used.

<The manufacturing method of a heat conductive sheet>
The heat conductive sheet of the present invention has a multilayer structure including a metal foil layer and an organic polymer compound layer.
The manufacturing process of the heat conductive sheet is also within the scope of the present invention. The manufacturing process of the heat conductive sheet of the present invention includes the following processes.
(A) alternately forming metal foil layers and organic polymer compound layers to form a molded body having a multilayer structure;
(B) A step of slicing the molded body at an angle of 0 to 30 degrees with respect to a normal line extending from the main surface.
Or you may employ | adopt the following (a ') process instead of the said (a) process.
(A ′) A step of forming a formed body having a multilayer structure by winding a laminate of the metal foil layer and the organic polymer compound layer with the orientation direction of the metal foil layer as an axis.

Hereinafter, each step will be described.
The step (a) of forming a molded body having a multilayer structure can be performed by laminating a metal foil layer and an organic polymer compound layer. The form of lamination is not particularly limited. For example, it is not limited to a form in which sheet-like materials constituting a plurality of independent layers are sequentially stacked, and at least each of a metal foil layer and an organic polymer compound layer is provided. The laminated body provided with each may be folded without cutting the end.

  In the case of a metal foil layer, the sheet-like material constituting each layer includes a metal foil or metal wire in a woven shape, a metal mesh or the like (hereinafter also referred to as “metal foil layer sheet”). It is done. In the case of an organic polymer compound layer, for example, a varnish containing an organic polymer compound is applied on a substrate, and when it has a curable component, a sheet-like material obtained by curing treatment (hereinafter, "Organic polymer compound layer sheet") may be used for lamination. It is also possible to directly form a varnish containing an organic polymer compound on the metal foil layer to form an organic polymer compound layer.

  Further, as another form of lamination in the step (a), the step (a ′) may be adopted. Specifically, a laminate including at least one metal foil layer and an organic polymer compound layer is provided. It is also possible to form a molded body by winding. The form of winding is not limited to the shape of the molded body being a cylindrical shape, and may be another shape such as a rectangular tube shape. In addition, although the laminated body should just be the structure which has a metal foil layer and an organic polymer compound layer one layer each, the layer structure of one layer or more may be sufficient.

The multilayer structure is formed by stacking the layers and pressing them using a press or laminating machine, or by applying a varnish containing an organic polymer compound on the metal foil layer as described above, Examples include a method of laminating molecular compound layers.
Moreover, when forming a multilayer structure, it is also possible to include layers other than a metal foil layer and an organic polymer compound layer. In addition, it is not necessary to alternate the sheet for metal foil layer and the sheet for organic polymer compound layer, but from the viewpoint of balance between thermal conductivity of metal foil layer and adhesion and adhesion of organic polymer compound layer. It is preferable to do.

  The shape of the molded body may be any shape as long as there is no inconvenience when slicing the molded body at an angle of 0 to 30 degrees with respect to the normal line from the main surface in the subsequent step (b). . For example, the shape of the sheet for each layer is formed into a circular shape, and a cylindrical formed body is produced by laminating them, and the subsequent slicing in the step (b) is performed by a method such as “wig removal”. It is also possible.

  In the step (a), the pressure at the time of lamination and the tensile force at the time of winding are weak enough that the sliced surface of the molded body is not crushed and the orientation of the metal foil layer is not collapsed in the (b) slicing step to be performed later. And it is desirable to adjust so that it may become strong to such an extent that the metal foil layer and organic polymer compound layer in a molded object adhere moderately. Usually, it is possible to obtain sufficient adhesion between the metal foil layer and the organic polymer compound layer by adjusting the pressure and tensile force when forming the molded body. However, when the adhesive force between the metal foil layer and the organic polymer compound layer is insufficient, even if a solvent or an adhesive is thinly applied between the metal foil layer and the organic polymer compound layer, lamination or winding may be performed. Good.

  The step of slicing the molded body of (b) is performed by slicing the molded body at an angle of 0 to 30 degrees with respect to the normal line extending from the main surface so that the heat conductive sheet has a predetermined thickness. To be implemented. Although the cutting tool which can be used at the time of a slice is not specifically limited, It is preferable to use a slicer, a cannula, etc. provided with a sharp blade. By using a cutting tool provided with a sharp blade, the orientation of the metal foil layer of the heat conductive sheet obtained after slicing is hardly disturbed, and a thin heat conductive sheet can be easily produced.

When the slicing angle is 30 degrees or less, the thermal conductivity of the obtained thermal conductive sheet is good. When the molded body is a laminate, it may be sliced (within the above angle range) so as to be perpendicular or substantially perpendicular to the lamination direction of the metal foil layer sheet and the organic polymer compound layer sheet. Further, when the molded body is a wound body, it may be sliced (within the above angle range) so as to be perpendicular or substantially perpendicular to the winding axis. As described above, in the case of a cylindrical molded body in which a circular metal foil layer sheet and an organic polymer compound layer sheet are laminated, the sheet may be sliced like a wig within the above angle range.
By slicing the molded body at an angle of 0 to 30 degrees with respect to the normal line, the resulting heat conductive sheet has a metal foil layer oriented at an angle of 0 to 50 degrees with respect to the thickness direction of the sheet. Become.

(B) A process is implemented in the range (Tg + 50 degreeC) 50 degreeC higher than the glass transition temperature (Tg) of the composition which comprises a heat conductive sheet-20 degreeC lower than Tg (Tg-20 degreeC). It is preferable. When the temperature at the time of slicing is Tg + 50 ° C. or less, not only does the molded body become flexible and it becomes difficult to perform slicing, but also the orientation of the metal foil layer in the heat conductive sheet is prevented from being disturbed.
On the other hand, when the temperature at the time of slicing is Tg−20 ° C. or higher, the molded body becomes hard and brittle, and it is difficult to perform slicing, and it is easy to avoid the thermal conductive sheet from cracking immediately after slicing. A more preferable temperature for slicing is a temperature range of Tg + 40 ° C. to Tg−10 ° C.

<Heat dissipation device>
The present invention also includes a heat dissipation device. The heat dissipating device of the present invention has a structure in which the heat conductive sheet of the present invention is interposed between the heat generating body and the heat dissipating body.
The heating element that can be used in the heat dissipation device of the present invention has at least a surface temperature not exceeding 200 ° C, and the temperature at which the heat conductive sheet of the present invention can be suitably used is in the range of -10 ° C to 120 ° C. is there. There is a high possibility that the surface of the heating element exceeds 200 ° C., for example, in the vicinity of the nozzle of a jet engine, around the inside of a kiln pot, around the inside of a blast furnace, around the inside of a nuclear reactor, outer space shell, etc. Since there is a high possibility that the organic polymer compound in the heat conductive sheet is decomposed, it tends to be unsuitable. Examples of the heating element suitable for the heat dissipation device of the present invention include a semiconductor package, a display, an LED, and an electric lamp.

  On the other hand, the heat radiator that can be used in the heat radiating device of the present invention is not particularly limited, and may be a typical one that is applied to the heat radiating device. For example, a heat sink using aluminum or copper fins or plates, an aluminum or copper block connected to a heat pipe, an aluminum or copper block in which cooling liquid is circulated by a pump, a Peltier element and this Examples include aluminum and copper blocks.

Instead of aluminum or copper, materials with a thermal conductivity of 10 W / mK or more, such as metals such as silver, iron, indium, graphite, diamond, aluminum nitride, boron nitride, silicon nitride, silicon carbide, aluminum oxide, etc. Those utilized are also preferred.
The heat dissipating device of the present invention is established by installing the heat conductive sheet of the present invention between the above-described heat generating body and the heat dissipating body and fixing each surface in contact. The heat conductive sheet is not particularly limited as long as it can be fixed in a state where the contact surfaces are sufficiently adhered, and any method may be used. However, from the viewpoint of maintaining sufficient contact between the contact surfaces, a method in which the pressing force is maintained is preferable. For example, the method of screwing using a spring and the method of inserting | pinching using a clip are mentioned. According to the heat dissipation device of the present invention, high heat dissipation efficiency can be achieved.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

  In each example, the thermal conductivity as an index of thermal conductivity and the tack strength as an index of adhesion were obtained by the following methods.

(Measurement of thermal conductivity)
The heat conductive sheet to be measured was cut into a size of 1 cm × 1 cm with a cutter, and the cut piece was placed so that one surface was in contact with the transistor (2SC2233) and the other surface was in contact with the aluminum heat dissipation block, thereby preparing a test sample. . Next, while pressing the transistor, current is passed through the test sample to measure the temperature of the transistor (T1, unit ° C) and the temperature of the heat dissipation block (T2, unit ° C). From the measured value and the applied power (W, unit W), The thermal resistance (X, unit ° C / W) was measured according to the following formula.

  From the obtained thermal resistance (X), the thickness of the cut piece (d, unit μm), and the correction coefficient C based on a known sample of thermal conductivity, the thermal conductivity (Tc, unit W / mK) was ) Was estimated.

(Measurement of tack strength)
It measured by the method (Probe diameter 5.1mm (phi), peeling speed 10mm / s, contact load 100gf / cm < ² >, contact time 1s) as described in JISZ0237-1991 using the Reska Co., Ltd. tacking tester.

Example 1
42.3 parts by mass of YDCN-703 (manufactured by Toto Kasei Co., Ltd., trade name: o-cresol novolac type epoxy resin, epoxy equivalent 210), Phenolite LF2882 (manufactured by Dainippon Ink & Chemicals, Inc., trade name: bisphenol A novolak) Resin) 23.9 parts by mass, HTR-860P-3 (manufactured by Nagase ChemteX Corporation, trade name: epoxy group-containing acrylic rubber, molecular weight 800,000, Tg-7 ° C.) 140 parts by mass, Curazole 2PZ-CN (Shikoku Chemicals) Industrial Co., Ltd., trade name: 1-cyanoethyl-2-phenylimidazole) 0.4 parts by mass and NUCA-187 (Nihon Unicar Co., Ltd., trade name: γ-glycidoxypropyltrimethoxysilane) 0.7 mass Add methyl ethyl ketone to the composition consisting of parts, stir and mix, and vacuum degas to organic polymer To obtain a compound containing varnish.

This organic polymer compound-containing varnish was applied onto a 50 μm thick release-treated polyethylene terephthalate (trade name: Purex S-31, manufactured by Teijin Ltd.), and dried by heating at 100 ° C. for 10 minutes and at 140 ° C. for 5 minutes. And it peeled from the said polyethylene terephthalate, and the sheet | seat for film-form organic polymer compound layers of thickness 10 micrometers was obtained.
Using the laminator, this film-like organic polymer compound layer sheet and an electrolytic copper foil (made by Furukawa Circuit Foil Co., Ltd., trade name “F0-WS”, foil thickness 9 μm) as a metal foil layer sheet are used. By alternately laminating at 60 ° C., a molded body having a multilayer structure with a thickness of 10 mm was obtained.

After cooling this molded body with dry ice, at a temperature of −10 ° C., the laminated section was sliced with a canna (at an angle of 5 degrees with respect to the normal line coming out of the copper foil surface), so that the heat of Example 1 was obtained. A conductive sheet was obtained.
When the cross section of the obtained heat conductive sheet was observed with an optical microscope and the angle of the metal foil layer with respect to the surface of the heat conductive sheet was measured, it was 8 degrees, and the metal foil layer was 0 to 50 degrees in the thickness direction of the heat conductive sheet. Orientation was observed at an angle.
The obtained heat conductive sheet had a heat conductivity of 32 W / mK, and a tack strength of 0.21 N and a good value.

(Example 2)
The organic polymer compound-containing varnish obtained in Example 1 was applied onto an electrolytic copper foil (Furukawa Circuit Foil Co., Ltd., trade name “F0-WS”, foil thickness 9 μm) as a metal foil layer sheet. And dried at 100 ° C. for 10 minutes and 140 ° C. for 5 minutes to obtain a copper foil with an organic polymer compound layer having a thickness of 10 μm.
This copper foil with an organic polymer compound layer was alternately laminated at 60 ° C. using a laminator to obtain a molded body having a multilayer structure with a thickness of 10 mm. After cooling this molded body with dry ice, the laminated section was sliced at a temperature of −10 ° C. with a canna (at an angle of 5 degrees with respect to the normal line coming out of the copper foil surface), so that the heat of Example 2 was obtained. A conductive sheet was obtained.

  The cross section of the obtained heat conductive sheet was observed with an optical microscope, and the angle of the metal foil relative to the surface of the heat conductive sheet was measured to be 6 degrees. The metal foil was at an angle of 0 to 50 degrees in the thickness direction of the heat conductive sheet. Orientation was observed. The obtained heat conductive sheet had a heat conductivity of 43 W / mK and a tack strength of 0.25 N and a good value.

(Comparative Example 1)
The film-like organic polymer compound layer sheet obtained in Example 1 was used as the heat conductive sheet of Comparative Example 1, and the tack strength was measured to be 0.45 N, but the heat conductivity was 0.6 W. The value was as low as / mK.

(Comparative Example 2)
The copper foil with an organic polymer compound layer obtained in Example 2 was used as the heat conductive sheet of Comparative Example 2, and the heat conductivity was measured to show a low value of 1.4 W / mK, and the tack strength of the resin surface was 0. The copper foil surface showed no adhesion with 0N.

(Comparative Example 3)
The electrolytic copper foil used in Example 1 (manufactured by Furukawa Circuit Foil, trade name “F0-WS”, foil thickness 9 μm) was used as the heat conductive sheet of Comparative Example 3. The tack strength was 0N and adhesion was low, and when the thermal conductivity was measured, it showed a low value of 11 W / mK.

  According to the present invention, it is possible to provide a thermal conductive sheet having high thermal conductivity and capable of easily adding performance such as adhesion and adhesion as required.

Claims (7)

  In the heat conductive sheet having a multilayer structure including a metal foil layer and an organic polymer compound layer, the metal foil layer is laminated in two or more layers in one direction with respect to the surface of the heat conductive sheet, The molecular compound layer contains at least an organic polymer compound, each of the metal foil layers is bonded by the organic polymer compound layer, and the metal foil layer is oriented in the thickness direction of the heat conductive sheet. The heat conductive sheet characterized by the above-mentioned.   The heat conductive sheet according to claim 1, wherein the metal foil layer laminated in two or more directions in one direction is oriented at an angle of 0 to 50 degrees with respect to the thickness direction of the sheet.   The heat conductive sheet according to claim 1, wherein the organic polymer compound is a poly (meth) acrylate polymer compound.   The metal foil layer includes at least one of copper, aluminum, iron, stainless steel, gold, silver, nickel, palladium, chromium, molybdenum, and alloys thereof. The heat conductive sheet as described. A method for producing a heat conductive sheet having a multilayer structure including the metal foil layer and the organic polymer compound layer,
The metal foil layer and the organic polymer compound layer are alternately laminated to form a molded body having a multilayer structure, and the molded body is at an angle of 0 to 30 degrees with respect to a normal line extending from the main surface. And a step of slicing. A method for producing a heat conductive sheet having a multilayer structure including the metal foil layer and the organic polymer compound layer,
A step of winding a laminate of the metal foil layer and the organic polymer compound layer around the orientation direction of the metal foil layer to form a molded body having a multilayer structure; and And a step of slicing at an angle of 0 to 30 degrees with respect to the outgoing normal.   It has the structure which interposed the heat conductive sheet as described in any one of Claims 1-4 between the heat generating body and the heat radiator, The heat radiator characterized by the above-mentioned.