TW202138535A - Heat conductive material and method for manufacturing heat conductive material, heat radiation structure and method for manufacturing heat radiation structure, electronic device - Google Patents

Abstract

The present invention provides a method for producing a thermally conductive material, said method comprising a stacking step for obtaining a prepreg multilayer body by stacking prepregs, in each of which carbon fibers are oriented in a certain direction, in such a manner that the carbon fibers have the same orientation direction, and subsequently applying a pressure to the prepregs at room temperature.

Description

Thermal conductive material and manufacturing method thereof, heat dissipation structure and manufacturing method thereof, and electronic equipment

The present invention relates to a method for manufacturing a thermally conductive material and a thermally conductive material, a method for manufacturing a heat-dissipating structure, a heat-dissipating structure, and an electronic machine.

A method of disposing a heat conductive material such as a heat conductive sheet between a heating element such as a semiconductor chip and a heat sink such as a heat sink has been widely carried out. In order to have high thermal conductivity and improve thermal conductivity, the required characteristics of these heat-dissipating materials include conformity to the surface shape of the heating element and the heat-dissipating member.

As one of the materials constituting this kind of heat conduction material, carbon fiber is widely used, and the heat conduction sheet in which the carbon fiber is aligned in the direction of heat conduction is known. For example, the following method of manufacturing a thermally conductive material has been proposed: preparing a carbon fiber sheet formed by fixing bundled carbon fibers with a fusible resin, then laminating it, impregnating it with a thermosetting adhesive resin, and curing it. This cured product is cut at a specific thickness and angle (for example, refer to Patent Document 1).

In addition, the following thermal conductive sheet has also been proposed: extruding a resin composition with carbon fibers dispersed in a die to form a molded body in which the length direction of the carbon fibers is aligned toward the extrusion direction, and then curing the cured product to a specific The thickness of the heat conduction sheet is cut (for example, refer to Patent Document 2). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2002-46137 A [Patent Document 2] Japanese Patent Application Publication No. 2015-45019

[The problem to be solved by the invention]

However, in the method described in Patent Document 1, although the carbon fiber filling amount in the thermal conductive sheet can be increased, since the thermal conductive sheet is a cured product of a thermosetting resin, it inherently lacks flexibility and cannot fully exhibit the excellent properties of carbon fiber. The thermal conductivity. In addition, although the heat-conducting sheet described in Patent Document 2 is excellent in following the surface shape of the heating element and the heat dissipation member, the filling amount of carbon fiber is relatively low, so compared to the heat-conducting sheet of Patent Document 1 Poor sex. The subject of the present invention is to solve the above-mentioned problems in the past and achieve the following objects. That is, the object of the present invention is to provide a thermally conductive material having excellent adhesion and high thermal conductivity and a method of manufacturing the same, a heat dissipation structure using the thermally conductive material and a method of manufacturing the same, and an electronic device. [Technical means to solve the problem]

The methods used to solve the above problems are as follows, namely: <1> A method of manufacturing a thermally conductive material, which includes the following laminating step: laminating a prepreg with carbon fibers aligned in a certain direction so that the alignment direction of the carbon fibers is consistent, and pressing at room temperature to obtain the prepreg Volume layer body. <2> The method of manufacturing a thermally conductive material as in the above <1>, which includes the cutting step of cutting the prepreg bulk layer in a direction substantially perpendicular to the alignment direction of the carbon fibers. <3> The method for manufacturing a heat conductive material as described in the above <1> or <2>, wherein the carbon fiber is a pitch-based carbon fiber. <4> The method for producing a thermally conductive material according to any one of the above <1> to <3>, wherein the prepreg is obtained by impregnating the carbon fiber in a thermosetting resin. <5> A thermally conductive material, which is a semi-hardened product of a thermosetting resin composition containing at least carbon fibers, and is a laminate in which the carbon fibers are aligned in the thickness direction. <6> A method for manufacturing a heat dissipation structure, the heat dissipation structure system is composed of a heating element, a heat conductive material and a heat dissipation member, and is characterized by: Between the heating element and the heat dissipating member, the semi-cured material of the thermally conductive material manufactured by the method of manufacturing the thermally conductive material in any one of the above <1> to <4> is sandwiched, and the half of the thermally conductive material is The hardened object is heated to harden it. <7> A heat dissipation structure, which is composed of a heating element, a heat conductive material and a heat dissipation member, and is characterized by: Between the heating element and the heat dissipating member, there is a hardened product of the heat conductive material of the above <5>, The heating element and the heat dissipating member have adhesiveness with the hardened material of the heat conductive material, Here, the above-mentioned adhesiveness refers to the peeling test of 90∘ peeling test at a tensile speed of 50mm/min measured at room temperature after being hardened for 1 hour at 150°C by bonding stainless steel plate and copper foil with a thermally conductive material. The force is 1N/cm or more. <8> An electronic device having the heat dissipation structure of the above <7>. <9> A silicon wafer having the heat conductive material of the above <5>. [Effects of Invention]

The present invention can solve the above-mentioned problems in the past, achieve the above-mentioned objects, and provide a thermally conductive material with excellent adhesion and high thermal conductivity and its manufacturing method, a heat-dissipating structure using thermally conductive material and its manufacturing method, and electronic equipment.

(Method of manufacturing heat conductive material) The manufacturing method of the thermally conductive material of the present invention preferably includes a lamination step, a cutting step, and other steps as required.

＜Layering Steps＞ The laminating step is the following steps: laminating a prepreg with carbon fibers aligned in a certain direction so that the alignment directions of the carbon fibers are consistent, and pressing at room temperature to obtain a prepreg bulk layer.

In the layering step, the prepreg is layered to produce a prepreg bulk layered body. The alignment directions of the carbon fibers in the prepreg constituting the prepreg volume layer body are preferably the same. However, within the range that does not hinder the thermal conductivity of the thermally conductive material, for the purpose of increasing the strength of the thermally conductive material, for example, the prepreg can also be arranged in the following way: the number of laminated sheets for every 5-10 sheets of carbon fiber in the same alignment direction , The alignment direction of one piece of carbon fiber is approximately perpendicular to the alignment direction of the five to ten pieces.

As a method to obtain the prepreg bulk layer, the prepreg is drawn out from the state of the wound body, and the prepreg can be pressed by stacking one sheet, or by stacking several sheets and then pressing (press), or it can be self-winding The body is cut out and overlapped with the necessary number of layers and then press. In addition, in order to obtain the thickness of the laminate, this step can be repeated repeatedly. Alternatively, the prepreg may be laminated to the necessary thickness, and press once using a pressing machine or the like to obtain a prepreg bulk layered body.

The above-mentioned pressurization can be performed by using one of a flat plate and an indenter with a flat surface to perform the pressurization device, for example. In addition, it can also be carried out using a pinch roll. If it is manufactured in a small area and in a small amount and the necessary characteristics can be obtained, simple methods such as hand rollers can also be used. The pressure at the time of pressurization is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 0.1 MPa to 100 MPa, and more preferably 0.5 MPa to 95 MPa. The pressing time is not particularly limited, and can be appropriately selected according to the composition of the binder resin, the pressure, the area of the sheet, and the like.

The above-mentioned press is performed at room temperature. That is, heating and hardening of the prepreg is not performed during pressurization. Room temperature means a non-heated environment, for example, a temperature of 20°C to 30°C. The prepreg volume layer obtained by pressurizing at room temperature is arranged between the heating element and the heat dissipation member in a flexible state, and it has excellent followability to the respective surface shapes of the heating element and the heat dissipation member, and is in close contact Sexual improvement.

The number of laminated prepregs can be appropriately selected according to the thickness of the thermally conductive material and the number of thermally conductive materials to be obtained from the laminated body. For example, the number of laminated prepregs is preferably 100 to 200.

As the prepreg, what is called "UD prepreg" or what is called "cross prepreg" can be mentioned. The so-called "UD prepreg" is a state in which the carbon fibers are aligned in a certain direction, and the above-mentioned resin composition is impregnated with the carbon fibers to form a sheet in a semi-cured state. The so-called "cross prepreg" is a carbon fiber sheet formed by impregnating carbon fibers with carbon fibers in a vertical and horizontal direction, and then making it into a sheet in a semi-cured state. Among them, from the viewpoint of thermal conductivity, "UD prepreg" is preferable.

Although the mass ratio of the resin in the prepreg can be appropriately selected according to the degree of conductivity imparted when the thermally conductive material is made, it is preferably, for example, 20% by mass to 35% by mass.

In addition, the weight of the carbon fiber per unit area of the prepreg, namely the FAW (Fiber Areal Weight) value, can be based on the thermal resistance and thermal conductivity of the finally obtained thermally conductive material, and further based on the flexibility of the thermally conductive material before hardening. It is selected, but it is preferably, for example, 100 g/m ² to 250 g/m ² .

The thickness of the prepreg is unobstructed in the layering step. In addition, although the above thickness can be appropriately selected according to the thermal resistance and thermal conductivity imparted to the thermally conductive material, it is preferably 50 μm to 150 μm, for example.

As the prepreg, an appropriate manufacturer can be used, or a commercially available product can also be used. As the above-mentioned commercially available products, for example, GRANOC Prepreg NT81250-525S, NT81600-520S, NT81000-530S, NT91250-525S, NT91500-520S, NT61000-525S, NT61350-520S (all of the above are manufactured by Nippon Graphite Fiber Co., Ltd.) Manufacture, prepregs made by impregnating pitch-based carbon fibers with thermosetting resin), DIALEAD Prepreg HyEJ12M65PD, HyEJ28M45PD, HyEJ12M80QD, HyEJ34M65PD (all of the above are prepregs using pitch-based carbon fibers manufactured by Mitsubishi Chemical Co., Ltd.), Pyrofil Prepreg TR350C125, TR350C150, TR350E100R, TR350G175S, MRX350C125S (all of the above are prepregs using PAN-based carbon fiber manufactured by Mitsucishi Chemical Co., Ltd.), etc. These may be used individually by 1 type, and may use 2 or more types together.

The prepreg using the thermally conductive material of the present invention is composed of at least a resin composition and carbon fiber. The above-mentioned resin composition contains a thermosetting resin, so a thermosetting resin composition is preferable. The prepreg using the thermally conductive material of the present invention can use the same type of thermosetting resin composition, or can also be mixed with different types of thermosetting resin composition. From the viewpoint of ease of manufacture, it is preferable To use the same kind of thermosetting resin composition.

樹脂、酚樹脂、三聚氰胺樹脂、聚酯樹脂、氰酸酯樹脂、聚矽氧樹脂或該等樹脂之改質樹脂等。該等樹脂可單獨使用1種，亦可併用2種以上。自耐熱性及材料之選擇性、以及密接性之觀點而言，該等樹脂之中，更加為環氧樹脂。(Thermosetting resin) The thermosetting resin is not particularly limited as long as it is a compound having a thermosetting functional group, and it can be appropriately selected according to the purpose. Examples include epoxy resin, polyimide resin, and polyamide. Amine imine resin, three

Resins, phenol resins, melamine resins, polyester resins, cyanate ester resins, silicone resins or modified resins of these resins, etc. These resins may be used individually by 1 type, and may use 2 or more types together. From the viewpoint of heat resistance, material selectivity, and adhesion, among these resins, epoxy resins are more.

(Epoxy resin) Epoxy resin is at least one of the compounds containing more than one epoxy group (-C ₃ H _{5 O-) in one molecule.} Among these compounds, the epoxy resin preferably contains two or more epoxy groups in one molecule. The epoxy resin may be a monomer or a state of a prepolymer obtained by partially reacting the monomer with a curing agent or the like.

The epoxy resin is not particularly limited, and can be appropriately selected depending on the purpose. Examples include: glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, and phenolic resin. Varnish type epoxy resin, cycloaliphatic type epoxy resin, long-chain aliphatic type epoxy resin, etc. These resins may be used individually by 1 type, and may use 2 or more types together.

As a glycidyl ether type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, etc. are mentioned, for example. In addition, it may also be an ethylene oxide-modified bisphenol A epoxy resin in which an ethylene oxide chain is contained in the skeleton. As a novolak type epoxy resin, a cresol novolak type epoxy resin, a phenol novolak type epoxy resin, etc. are mentioned, for example. Examples of other types of epoxy resins include flame-retardant epoxy resins, hydantoin epoxy resins, isocyanurate epoxy resins, and the like.

Regarding the properties of epoxy resins, there are no special restrictions. You can choose from the ease of manufacture of prepregs or the fusion properties of laminated prepregs. For example, you can mix and use epoxy resins in liquid form at 25°C. The solid epoxy resin can also be used by mixing two or more solid epoxy resins by heating and melting. In addition, in the solid epoxy resin, the softening point can also be appropriately selected according to the desired physical properties.

(hardener) The thermosetting resin composition further preferably contains at least one curing agent. As the curing agent, a thermosetting resin can be thermally cured, and there is no particular limitation, and it can be selected appropriately. Examples of the curing agent when the thermosetting resin is epoxy resin include acid anhydride curing agents, aliphatic amine curing agents, aromatic amine curing agents, phenol curing agents, mercaptan curing agents, etc. The compound hardener, imidazole and other catalyst-type hardeners, etc. In addition, examples include: an addition molding latent hardener obtained by excessively reacting imidazole or the like with glycidyl group of epoxy resin, or a microcapsule type latent hardener obtained by further microencapsulating this with isocyanate or the like Wait.

(Hardening accelerator) The thermosetting resin composition can be combined with a curing accelerator as needed. By using a hardening accelerator together, it can be further hardened sufficiently. The type or content of the hardening accelerator is not particularly limited. Although it can be appropriately selected according to the purpose, it is preferable to select an appropriate hardening accelerator from the viewpoints of reaction rate, reaction temperature, and storage stability. Examples of hardening accelerators include imidazole-based compounds, organophosphorus-based compounds, tertiary amines, and quaternary ammonium salts. These hardening accelerators may be used individually by 1 type, and may use 2 or more types together.

(Other ingredients) The thermosetting resin composition may contain other components as long as the effects of the present invention are not impaired. As the above-mentioned other components, from the viewpoints of improving thermal conductivity and adjusting the strength of the prepreg, for example, inorganic fillers such as alumina, aluminum nitride, and boron nitride can be added. In addition, from the viewpoint of adjusting the fluidity of the thermosetting resin composition, fine powders of metal oxides such as fumed silica can be added. Moreover, from the viewpoint of the impregnability of the carbon fiber resin, for example, auxiliary agents such as a silane coupling agent and an aluminum chelate compound can be added.

＜Carbon Fiber＞ The carbon fiber is not particularly limited and can be appropriately selected according to the purpose. For example, pitch-based carbon fiber, PAN-based carbon fiber, carbon fiber obtained by graphitizing PBO fiber, arc discharge method, laser evaporation method, CVD method (chemical gas Phase deposition method), CCVD method (catalyst chemical vapor deposition method) and other synthetic carbon fibers. These may be used individually by 1 type, and may use 2 or more types together. Among these, from the viewpoint of thermal conductivity, carbon fibers obtained by graphitizing PBO fibers, carbon fibers obtained by graphitizing PAN fibers, and pitch-based carbon fibers are preferred, and pitch-based carbon fibers are particularly preferred.

The average fiber diameter (average minor axis length) of the above-mentioned carbon fiber is not particularly limited. Although it can be appropriately selected according to the purpose, it is preferably 4 μm to 20 μm, and more preferably 5 μm to 14 μm.

As the thermal conductivity of the carbon fiber itself, although it can be appropriately selected according to the desired thermal conductivity when the thermally conductive material is made, it is preferably 150 W/m‧K to 1400W/m‧K.

Furthermore, from the viewpoint of improving the affinity with the impregnated resin, the carbon fiber may be coated with epoxy resin or the like on the surface, for example.

<cutting step> The cutting step is a step of cutting the prepreg bulk layer in a direction substantially perpendicular to the alignment direction of the carbon fibers. Cutting can be performed using a slicing device, for example. As the slicing device, if it is a means that can cut the prepreg volume layer, it is not particularly limited, and a well-known slicing device, such as an ultrasonic cutting machine, a plane, etc., can be appropriately used.

＜Other steps＞ The other steps are not particularly limited, and can be appropriately selected according to the purpose, such as a surface coating step, a sheet production step, and the like.

(Heat conductive material) The heat conductive material of the present invention is a semi-hardened product of a thermosetting resin composition impregnated at least with carbon fibers, and is a laminate in which the carbon fibers are aligned in the thickness direction. Regarding carbon fiber, thermosetting resin, etc., the same as those described in the method of manufacturing the thermally conductive material can be used. Semi-cured material refers to the state of the prepreg bulk layer that has not been heat-cured (not completely cured). It means that "the prepreg bulk layer has flexibility between the heating element and the heat dissipation member, and has the respective The state of the followability of the surface shape. Arrange the semi-cured material of the thermally conductive material in such a way as to contact the heating element or heat dissipating member, and then formally harden it by heating or the like, whereby the layer containing the heat conductive material as the hardened material and the heating element or the heat dissipating member The tightness is improved.

There are no particular restrictions on the shape and thickness of the thermally conductive material, and it can be appropriately selected according to the purpose. As the shape of the thermally conductive material, for example, a sheet shape, a plate shape, etc. may be mentioned. The thickness of the thermally conductive material is not particularly limited, and can be appropriately set according to the application, and is preferably 0.1 mm to 3.0 mm.

(Method of manufacturing heat dissipation structure) The manufacturing method of the heat dissipation structure of the present invention is a method of manufacturing a heat dissipation structure composed of a heating element, a heat conduction material, and a heat dissipation member. Between the heating element and the heat dissipating member, the semi-cured material of the thermally conductive material manufactured by the method of manufacturing the thermally conductive material of the present invention is sandwiched, and the semi-cured material of the thermally conductive material is heated and hardened.

First, the heating element and the heat dissipating member are sandwiched between the semi-hardened heat conductive material manufactured by the method of manufacturing the heat conductive material of the present invention, and the semi-hardened heat conductive material is arranged in a manner that follows the respective surface shapes of the heating body and the heat dissipating member Things.

Secondly, heat the semi-hardened material of the thermally conductive material in this state. As a means of heating the semi-hardened material of the thermally conductive material, for example, the heating element and the heat dissipating member can be heated together through the reflow furnace, or by the oven. When the heating element is a semiconductor chip, a semiconductor element, or a resistor, the heating can also be generated by energization.

Since the semi-cured material of the heat conductive material before heating is cut from the prepreg bulk layer body on which the prepreg is laminated without heating, the state of the resin is a semi-cured state. Heating is carried out with the heat-conducting material sandwiched between the heating element and the heat dissipating member, so that the semi-hardened material of the heat-conducting material is completely hardened.

The semi-cured material of the heat conductive material is completely hardened in the state of sandwiching the heat conductive material between the heating element and the heat dissipating member, thereby maintaining the adhesion to the heating element and the heat dissipating member, and then bonding with each other, compared to the complete hardening When the heat conductive material is arranged between the heating element and the heat dissipation member, a heat dissipation structure with better heat dissipation and adhesion can be made.

(Heat dissipation structure) The heat dissipation structure of the present invention is a heat dissipation structure composed of a heating element, a heat conduction material, and a heat dissipation member. Between the heating element and the heat dissipating member, there is a hardened product of the heat conductive material of the present invention, The heating element and the heat dissipating member have adhesiveness with the cured product of the heat conductive material. Here, the above-mentioned adhesion refers to the peeling force of 90∘ peeling test at a tensile speed of 50mm/min measured at room temperature after being cured at 150°C for 1 hour by bonding stainless steel plates and copper foils with thermally conductive materials It is 1N/cm or more. Room temperature means a non-heated environment, for example, a temperature of 20°C to 30°C.

As the heat dissipation structure, for example, it is composed of "heating elements such as electronic parts", "heat sinks, heat pipes, heat spreaders, etc. heat dissipation members", and "heat conduction materials sandwiched between the heating elements and heat dissipation members".

The electronic components are not particularly limited, and can be appropriately selected according to the purpose, and examples include CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Rocessing Unit), and the like.

As the heat dissipation structure, as long as it is a structure that dissipates the heat emitted by the electronic component (heating element), it is not particularly limited, and can be appropriately selected according to the purpose. Examples include: heat sink, heat sink, vapor chamber), heat pipe, etc. The heat sink is a component used to efficiently transfer the heat of the electronic component to other components. The material of the heat sink is not particularly limited, and can be appropriately selected according to the purpose, and examples thereof include copper, aluminum, and the like. The above-mentioned heat sink is generally in the shape of a flat plate. The heat sink is a member for dissipating the heat of the electronic component to the air. The material of the heat sink is not particularly limited, and can be appropriately selected according to the purpose, and examples thereof include copper, aluminum, and the like. The heat sink described above has, for example, a plurality of fins. The heat sink has, for example, a base and "a plurality of fins arranged in a manner extending in a non-parallel direction (for example, orthogonal direction) with respect to a surface of the base." The heat sink and the heat sink are usually solid structures with no space inside. The above-mentioned uniform temperature plate is a hollow structure. A volatile liquid is enclosed in the internal space of the hollow structure. Examples of the heat equalizing plate include a plate-shaped hollow structure in which the heat sink has a hollow structure, and the heat sink has a hollow structure. The heat pipe is a cylindrical, substantially cylindrical, or flat cylindrical hollow structure. A volatile liquid is enclosed in the internal space of the hollow structure.

Here, FIG. 1 is a schematic diagram of a semiconductor device as an example of the heat dissipation structure of the present invention. 1 is a schematic cross-sectional view of an example of a semiconductor device. The heat conduction sheet 1 of the present invention dissipates the heat emitted by the electronic parts 3 such as semiconductor elements, and as shown in FIG. Between the heat sink 2. In addition, the heat conducting sheet 1 is sandwiched between the heat sink 2 and the heat sink 5. Furthermore, the heat conducting sheet 1 and the heat sink 2 together constitute a heat dissipation member for dissipating the heat of the electronic component 3.

The heat sink 2 is formed in, for example, a square plate shape, and has a main surface 2a opposed to the electronic component 3 and a side wall 2b established along the outer periphery of the main surface 2a. The heat sink 2 is provided with a heat conductive sheet 1 on the main surface 2a surrounded by the side wall 2b, and a heat sink 5 is provided on the other surface 2c opposite to the main surface 2a via the heat insulating conductive sheet 1. The higher the thermal conductivity of the heat sink 2 is, the lower the thermal resistance, and the more efficiently absorb the heat of the electronic components 3 such as semiconductor elements. Therefore, for example, it can be formed of copper or aluminum with good thermal conductivity.

The electronic component 3 is, for example, a semiconductor element such as BGA, and is mounted on the wiring board 6. In addition, the front end surface of the side wall 2b of the heat sink 2 is also constructed on the wiring substrate 6, whereby the electronic component 3 is surrounded by the side wall 2b at a specific distance.

Thereafter, by adhering the heat conducting sheet 1 to the main surface 2a of the heat sink 2 to absorb the heat emitted by the electronic component 3, a heat sink 5 is formed to dissipate heat. The bonding of the heat sink 2 and the heat conductive sheet 1 can be performed by the adhesive force of the heat conductive sheet 1 itself.

(Silicon wafer) As the heat dissipation structure of the present invention and the manufacturing method thereof, the following aspects are listed: As shown in (A) of FIG. 2, the thermally conductive material 11 of the present invention is attached to the surface opposite to the circuit formation surface of the silicon wafer 12 on which the semiconductor circuit is formed. Next, the silicon wafer in this state is mounted on a dicing frame with a dicing tape, and then a dicing machine or the like is used to form a semiconductor chip with a thermally conductive material and singulate it (refer to Figure 2(B), (C)).

Secondly, as shown in FIG. 2(D), the singulated semiconductor chip 13 with thermally conductive material is mounted on, for example, an organic substrate 15 and placed in contact with a heat sink 14 such as a heat sink or heat sink. In Fig. 2(D), 11 is the thermal conductive material of the present invention, and 16 is solder.

Afterwards, for example, the reflow furnace is used to heat it while simultaneously performing "assembly of a semiconductor chip with thermally conductive material on an organic substrate" and "attachment of heat dissipation members such as heat sinks to the semiconductor chip".

By going through the above-mentioned steps, it is possible to simultaneously perform "assembly of electronic parts (semiconductor chips) as heating elements on substrates" and "steps of connecting electronic parts with heat sinks or heat sinks, etc.", which can be further The improvement of production efficiency.

(Electronic equipment) The electronic device of the present invention has the heat dissipation structure of the present invention. As an example of an electronic device, a semiconductor device using a semiconductor element as an electronic component, etc. are mentioned. [Example]

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited by these embodiments.

GRANOC Prepreg NT81250-525S (carbon fiber diameter 10 μm, FAW value 125 g/m ² , thermosetting resin composition content 25% by mass, thickness 90 μm, Nippon (Manufactured by Graphite Fiber Co., Ltd.) laminated in such a way that the alignment direction of the carbon fiber is the same direction. Laminate at room temperature (25°C), press hand rollers for each layer of 1 sheet, and finally layer 180 sheets. Obtain a prepreg volume layer with a height of 23 mm × a width of 10 cm × a length of 5 cm. Secondly, slice the prepreg volume layer along a direction approximately perpendicular to the alignment direction of the carbon fibers to obtain a thermally conductive material in a semi-hardened state with carbon fibers aligned in the thickness direction with a thickness of 300 μm (0.3 mm).

Next, regarding the obtained semi-hardened heat conductive material, the thermal resistance and thickness were measured as described below, and the adhesiveness was evaluated. The results are shown in Table 1.

<Measurement of thermal resistance> The obtained semi-hardened heat conductive material is cut into a circle with a diameter of 20 mm, clamped by copper plates, and heated at 150°C for 1 hour to harden the heat conductive material to obtain a test piece. Using ASTM-D5470 as the standard method, with a ^{load of 3 kgf/cm 2} , the thermal resistance of the obtained test piece was measured [℃‧cm ² /W]. In addition, a feeler gauge is used to measure the thickness of the thermally conductive material after thermal hardening.

＜Evaluation of Adhesion＞ Cut the copper foil with polyimide film as the substrate material to 10 mm × 100 mm. A semi-hardened thermal conductive material with a thickness of 0.3 mm is attached to the test piece in such a way that it becomes 10 mm wide × 50 mm long from the end of the copper foil. Using a 2kg roller, the copper foil attached with the thermally conductive material in the semi-hardened state is reciprocated once and attached to the SUS304 board in accordance with JIS G4305. In this state, after heating at 150°C for 1 hour to harden the thermally conductive material, it was allowed to stand at room temperature (25°C) for 24 hours to prepare a sample. The sample was set in a material testing machine (TENSILON RTG1250, manufactured by A&D Co., Ltd.), and subjected to a 90∘ peel test at a tensile speed of 50 mm/min to measure the peel force, and the adhesion was evaluated based on the following criteria. [Evaluation Criteria for Adhesion] ○: Adhesive; the peeling force of 90∘ peeling test is 1N/cm or more; ╳: No adhesion; the peeling force of 90∘peeling test is less than 1N/cm.

(Comparative example 1) ＜Thermal resistance＞ In Comparative Example 1, the thermally conductive material and the test piece were obtained under the same conditions as in Example 1, except that the thermally conductive material was heated at 150° C. for 1 hour to harden the thermally conductive material before being clamped to the copper plate. The thermal resistance and thickness of the above test piece were measured in the same manner as in Example 1, and the results are shown in Table 1.

＜Adhesion＞ In Comparative Example 1, a semi-cured thermally conductive material with a thickness of 0.3 mm was attached to a copper foil with a polyimide film as a substrate material, and the state was maintained at 150°C for 1 hour of heat curing. Although I tried to attach this to a SUS304 board, it could not be attached (the peel force could not be measured). The results are shown in Table 1.

[Table 1] Example 1 Comparative example 1 Thickness (mm) 0.22 0.21 Thermal resistance (℃‧cm ² /W) 0.352 9.57 Adhesion Peeling force (N/cm) 2 Unable to determine Evaluation 〇 X From the results in Table 1, it can be seen that Example 1 did not heat-harden at the time when the carbon fiber-containing heat-conducting material was obtained, but was heat-hardened after being clamped by a copper plate, so it followed the surface shape of the copper plate and adhered to the copper plate. , Good adhesion and thermal conductivity, low thermal resistance. On the other hand, it can also be seen that since the thermal conductive material obtained in Comparative Example 1 is heated and hardened and clamped by copper plates, the followability to the surface shape of the copper plate is low and the adhesion is also poor, so it is compared with Example 1 The resistance is higher.

1: Heat conduction material (heat conduction sheet) 2: Heat dissipation member (heat sink) 2a: Main surface 2b: side wall 2c: Other surfaces on the opposite side to the main surface 3: Heating element (electronic parts) 3a: upper surface 5: Heat dissipation components (heat sink) 6: Wiring board 11: Thermal conductive material 12: Silicon wafer 13: Semiconductor wafer 14: Heat dissipation components 15: Organic substrate 16: Solder

Fig. 1 is a schematic cross-sectional view showing an example of the heat dissipation structure of the present invention. [FIG. 2] A diagram showing an example of the steps of manufacturing a heat dissipation structure with a silicon wafer attached with the thermally conductive material of the present invention.

Claims (9)

A method for manufacturing a thermally conductive material, which includes the following laminating steps: laminating a prepreg with carbon fibers aligned in a certain direction so that the alignment direction of the carbon fibers is consistent, and pressing at room temperature to obtain a prepreg bulk layer body. The method for manufacturing a thermally conductive material according to claim 1, which includes the following cutting step: cutting the prepreg bulk layer in a direction substantially perpendicular to the alignment direction of the carbon fibers. According to claim 1 or 2, the method of manufacturing a thermally conductive material, wherein the carbon fiber is pitch-based carbon fiber. The method for producing a thermally conductive material according to any one of claims 1 to 3, wherein the prepreg is obtained by impregnating the carbon fiber in a thermosetting resin. A thermally conductive material is a semi-hardened product of a thermosetting resin composition containing at least carbon fibers, and is a laminate in which the carbon fibers are aligned in the thickness direction. A method for manufacturing a heat dissipation structure. The heat dissipation structure system is composed of a heating element, a heat conduction material and a heat dissipation member, and is characterized in that: Between the heating element and the heat dissipating member, a semi-hardened product of a thermally conductive material manufactured by the method for manufacturing a thermally conductive material in any one of claims 1 to 4 is clamped, and the semi-hardened product of the thermally conductive material is Heat to harden. A heat dissipation structure, which is composed of a heating element, a heat conduction material and a heat dissipation member, and is characterized in that: Between the heating element and the heat dissipating member, there is a hardened product of the thermal conductive material of claim 5, The heating element and the heat dissipating member have adhesiveness with the hardened material of the heat conductive material, Here, the above-mentioned adhesiveness refers to the peeling of the stainless steel plate and the copper foil by bonding the stainless steel plate and the copper foil with a thermally conductive material, and after curing for 1 hour at 150°C, the peeling test at a tensile speed of 50mm/min measured at room temperature at 90° The force is 1N/cm or more. An electronic machine having the heat dissipation structure of claim 7. A silicon wafer having the thermally conductive material of claim 5.

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