JP2000191987A - Thermally conductive adhesive film and semiconductive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermally conductive adhesive film having good peel strength, excellent in heat-releasing property and useful for semiconductor devices by orientating carbon fiber to which a ferromagnetic material is applied in a definite direction and forming the carbon fiber into a sheet by using a solid-like adhesive. SOLUTION: A carbon fiber to which a ferromagnetic material comprising at least one kind of metal, alloy or compound selected from a group comprising nickel-based, iron-based, ferrite-based, chromium-based, cobalt-based, manganese-based or rare earth- based compound, e.g. nickel is applied in a range of film thickness of 0.01-5 μm by electroless plating method is orientated in definite direction and at least one side of carbon fiber having 10 μm to 2 mm thickness is subjected to electric insulating treatment by using a thermosetting solid-like adhesive in semi-cured state containing at least one kind of polymer selected from a group of epoxy-based, polyimide-based, acrylic, urethane-based, vinyl-based and silicone-based resins and thermoplastic elastomer to provide the objective thermally conductive adhesive film. A semiconductor element 8 and a heat transfer member such as die pad are bonded and integrated with the above adhesive film 3 to produce the objective semiconductive device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat conductive adhesive film which is required to have a high heat conductivity for effectively dissipating heat generated from components such as a semiconductor element, a power supply, and a light source used in electric products. The present invention relates to a semiconductor device having excellent heat dissipation.

[0002]

2. Description of the Related Art Conventionally, various heat conductive adhesive films have been used for the purpose of bonding a semiconductor element or an electronic component that generates heat to a heat transfer member or an insulating substrate that dissipates heat to a metal foil or an electrode. These heat conductive adhesive films include, in order to increase the heat conductivity, silver, copper, gold, aluminum, nickel or other metals or alloys having a high heat conductivity, compounds, or aluminum oxide, magnesium oxide,
Powdered filler made of electrically insulating ceramics such as silicon oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, etc., and powdered or fibrous heat conductive fillers such as carbon black and diamond are compounded. ing.

[0003] A heat conductive adhesive is known in which carbon fiber is blended with an adhesive polymer as a heat conductive filler. For example, Japanese Patent Application Laid-Open No. 63-305520 proposes a die bond material filled with carbon-based fine powder or carbon fiber. JP-A-6-212137 discloses an adhesive material filled with carbon fibers having a specific structure, that is, carbon fibers having a three-dimensional structure using a mesophase pitch as a base material, for the purpose of improving the heat conduction characteristics. Further, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 324127 discloses a die bonding material for a semiconductor element using a graphite material obtained by heat-treating a specific polymer material.

Further, Japanese Patent Application Laid-Open No. 5-209157,
According to Japanese Patent Application Laid-Open No. 6-299129, for an electronic device, the heat radiation characteristics are further improved by specifying the structure of the carbon fiber or metal fiber to be contained in a lump-like or thread-like shape, or a woven or non-woven fabric. Adhesive films have been proposed. On the other hand, JP-A-62-194653,
JP-A-63-62762 discloses a bonding method in which an adhesive containing a magnetic substance powder such as nickel is oriented in a thickness direction in a magnetic field to improve the thermal conductivity.

[0005]

However, the amount of heat generated by recent high-density and high-performance electronic components such as semiconductor devices and electric appliances tends to increase remarkably. An adhesive film having sufficiently high thermal conductivity could not be obtained by the conventional improvement method using a thermal conductive filler. In addition, a bonding method for orienting an adhesive containing a magnetic substance powder in a thickness direction in a magnetic field is as follows. In a normal powdery or needle-like nickel-based or iron-based material, the thermal conductivity of the material itself is 100 W / mK. Since it was less than that, it was not possible to develop a sufficiently high thermal conductivity as an adhesive even when oriented by a magnetic field. And the method of giving a magnetic field at the time of bonding was not always simple.

That is, since an adhesive film having even higher heat conduction properties has not been developed, electrochemical migration is accelerated due to a large amount of heat generated from electronic components such as semiconductor elements, and the formation of wiring and pad portions is accelerated. Corrosion has been promoted, and cracks have occurred or been broken in the constituent materials due to the generated thermal stress, and various troubles have occurred in which the interface of the joining portions of the constituent materials has separated and the life of the electronic component has been impaired.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a heat conductive material for effectively dissipating heat generated from components such as a semiconductor element, a power supply, and a light source used in electric appliances. An object of the present invention is to provide an adhesive film and a semiconductor device having excellent heat dissipation characteristics. That is, the present invention provides a heat conductive adhesive film comprising a carbon fiber and a solid adhesive, wherein the carbon fibers coated with the ferromagnetic material are oriented in a certain direction. It is an adhesive film. Further, the present invention provides a method for connecting a semiconductor element and a heat transfer member,
A semiconductor device characterized in that carbon fibers coated with a ferromagnetic material are adhered with a thermally conductive adhesive film oriented in a certain direction.

[0008] The carbon fiber coated with a ferromagnetic material used in the present invention is obtained by applying a ferromagnetic material to a carbon fiber by electroless plating, electrolytic plating, physical vapor deposition by vacuum vapor deposition or sputtering, chemical vapor deposition, or the like. It can be prepared by a method such as painting, dipping, or mechanochemical method of mechanically fixing fine particles to the carbon fiber surface. Ferromagnetic materials include nickel-based and nickel-based alloys, iron-based alloys, iron nitride-based,
Ferrite-based, barium ferrite-based, cobalt-based alloy, manganese-based alloy, and rare earth-based alloys such as neodymium / iron / boron-based and samarium / cobalt-based are used.
Among them, nickel, iron, ferrite, chromium,
A ferromagnetic material composed of at least one metal, alloy or compound selected from a cobalt-based, manganese-based or rare-earth-based compound is preferred.

The thickness of the ferromagnetic material to be coated is not limited, but is preferably in the range of 0.01 μm to 5 μm. If the thickness is less than 0.01 μm, the magnetism of the external magnetic field causes the carbon fibers coated with the ferromagnetic material to be oriented so that the magnetism is insufficient and the fibers are hardly oriented. If it exceeds 5 μm, it is easy to orient by magnetic force, but it is not preferable because the thermal conductivity of the adhesive film decreases. The more preferable thickness of the ferromagnetic material is in the range of 0.05 μm to 2 μm.

Further, as a pre-process of coating the carbon fiber with a ferromagnetic material, or on the surface of the carbon fiber after coating the ferromagnetic material, silver, copper, gold, aluminum oxide, magnesium oxide, aluminum nitride, silicon carbide, A known metal, alloy, ceramic, or the like having a high thermal conductivity such as, for example, may be coated so as to overlap to improve the thermal conductivity. When the ferromagnetic material to be coated is electrically conductive such as nickel, the outermost surface is coated with an electrically insulating ceramic or organic polymer material such as aluminum oxide, magnesium oxide, aluminum nitride, or silicon carbide. It is possible to make the heat conductive adhesive film of the present invention electrically insulating.

[0011] The type, size and shape of the carbon fiber are not specified. As for the raw material, the carbon fiber with a developed graphite structure, which is heat-treated at a high temperature exceeding 2000 to 3000 ° C. or 3000 ° C. after a process such as melt-spinning, infusibilization, and carbonization using a mesophase pitch system as a main material rather than a PAN system, is a fiber. It is preferable because the thermal conductivity in the length direction is large. Further, carbon fibers obtained by a vapor growth method can also be used. The thermal conductivity of this carbon fiber in the fiber length direction is preferably 200 W / mK or more, preferably 400 W / mK or more, and more preferably 1000 W / m.
K or more.

The average diameter of the carbon fiber is 5 to 20 μm.
m and an average length in the range of 10 to 800 μm are preferable because the solid adhesive can be easily filled and the heat conductivity of the obtained heat conductive adhesive film increases. When the average diameter is smaller than 5 μm or when the average length is longer than 800 μm, it is difficult to mix the solid adhesive with a high concentration. In addition, carbon fibers having an average diameter exceeding 20 μm
It is not preferable because the productivity is deteriorated. Average length is 1
When it is shorter than 0 μm, the bulk specific gravity becomes small, and problems may arise in handling and workability during the manufacturing process. In addition,
These carbon fiber surfaces may be previously subjected to a known oxidation treatment such as electrolytic oxidation.

Examples of the solid adhesive for filling the carbon fiber coated with the ferromagnetic material include epoxy-based, polyimide-based, which are solid at room temperature or solid when heated to a semi-cured state.
Acrylic, vinyl such as polyvinyl acetate, urethane, silicone, olefin, polyamide, polyamideimide, phenol, amino, bismaleimide, polyimide silicone, saturated and unsaturated polyester, diallyl phthalate Preferred are materials composed of known resins and rubbers such as synthetic rubbers, urea-based, melamine-based, alkyd-based, benzocyclobutene-based, synthetic rubber-based such as polybutadiene, chloroprene rubber, and nitrile rubber, natural rubber-based, and styrene-based thermoplastic elastomers. .

As for the curing form, any of known adhesive curing polymers such as thermosetting, thermoplastic, ultraviolet or visible light curable, room temperature curable, and moisture curable can be used. Among them, epoxy, polyimide, acrylic, etc., which have good adhesion to various metals and ceramics, plastics, rubber, and elastomers of materials that make up electronic components,
At least one thermosetting solid adhesive selected from urethane and silicone is preferred. Furthermore, when the solid adhesive is thermosetting, a heat conductive adhesive film which is filled with a carbon fiber coated with a ferromagnetic material, is oriented in a certain direction, and is in a semi-cured state such as a B stage is bonded. It is preferable in terms of strength and reliability. Also, for the purpose of surface treatment of the fiber, the surface of the carbon fiber coated with the ferromagnetic material is treated with a known coupling agent or sizing agent to improve the wettability with the solid adhesive or improve the filling property. It is possible to obtain a thermally conductive adhesive film that has been made.

The heat conductive adhesive film of the present invention contains a solvent, a thixotropic agent, a dispersant, a curing agent, a curing accelerator, a retarder, a tackifier, a plasticizer, a flame retardant, an antioxidant, and a stabilizer. A known additive such as a coloring agent can be blended. Particularly when the viscosity of the composition when compounding the solid adhesive and the carbon fiber coated with the ferromagnetic material was large, the ferromagnetic material was coated by adding a solvent to reduce the viscosity of the composition. The magnetic field orientation of the carbon fiber can be promoted. In addition, powder and fiber shaped metals and ceramics, specifically, silver, copper, gold, aluminum oxide,
Fillers used in conventional thermal conductive adhesives such as magnesium oxide, aluminum nitride, silicon carbide, and metal-coated resins, as well as ordinary carbon fibers that are not coated with ferromagnetic materials can also be used together It is.

Although the thickness of the film is not specified, it is preferably in the range of 10 μm to 2 mm.
When the carbon fiber coated with the ferromagnetic material to be blended is oriented in the thickness direction, it is preferable that the film thickness be larger than the length of the fiber used.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION As a method for producing the heat conductive adhesive film of the present invention, a composition prepared mainly from a carbon fiber coated with a ferromagnetic material and a solid adhesive is used. Apply the film on the sheet with a bar coater, blade, roll, etc.
A method is preferred in which a carbon fiber coated with a ferromagnetic substance in a film composition is oriented in a certain direction by an external magnetic field, heated to a semi-cured state, and dried. Even if the carbon fiber coated with the ferromagnetic material and the adhesive composition are liquid when uncured, they can be formed into a film by heating and drying to form a solid in a semi-cured state.

Next, by applying an external magnetic field when uncured and orienting the carbon fibers coated with the ferromagnetic material in the adhesive film along the lines of magnetic force, the thermal conductivity of the film corresponding to the orientation direction of the fibers is improved. Can be. In order to align and orient the fibers in the gap direction of the adherend, that is, in the thickness direction of the adhesive film, the N and S poles of the permanent magnet or electromagnet are opposed in the thickness direction, and the direction of the magnetic force lines is the desired fiber orientation. Install so that it corresponds to the direction.

On the other hand, in order to improve the thermal conductivity in the in-plane direction of the adhesive film, the fibers are aligned in the in-plane direction by making the N and S poles of the magnet face in a direction perpendicular to the thickness direction. Orientation. Alternatively, the N pole of the magnet and the N
Even when the poles or the S poles and the S poles face each other in the thickness direction, the fibers can be aligned in the in-plane direction. It is not always necessary to oppose the magnets on both sides, and the magnets disposed on only one side can also orient the carbon fibers coated with the ferromagnetic material in the adhesive film. The magnetic field generating means used as the external magnetic field may be a permanent magnet or an electromagnet, but the magnetic flux density is practically 200 to 20,000 gauss, and a good orientation can be achieved.

The larger the amount of the carbon fiber coated with the ferromagnetic material in the adhesive film, the higher the thermal conductivity of the adhesive film. However, in practice, if a large amount is filled, there may be problems such as difficulty in removing mixed air bubbles and difficult orientation. Therefore, although it can be arbitrarily determined according to the type of the carbon fiber coated with the ferromagnetic material, the solid adhesive and the solvent, the compounding agent, and the characteristics of the intended end product, the strength in the heat conductive adhesive film can be determined. The filling rate of the carbon fiber coated with the magnetic material is 5 to 90% by volume,
More preferably, the range of 10 to 60% by volume is practical.

For applications requiring electrical insulation,
This can be achieved by subjecting at least one surface of the film to an electrical insulating treatment. As a method of the electrical insulation treatment, a method of laminating an electrically insulative adhesive layer of 1 to 500 μm made of a composition not containing carbon fibers coated with a conductive ferromagnetic material is preferable. In addition, the electrically insulating adhesive layer contains a high thermal conductivity filler such as silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, silicon carbide, etc., so that the entire adhesive layer has a heat conductive property. It is desirable to keep the rate high. On the other hand, the electrical insulation can be maintained by using a fiber in which the outermost surface of the carbon fiber coated with a ferromagnetic material is made of a ceramic or polymer coated with an electrically insulating material.

1 to 4 by adhering a heat conductive adhesive film in which a carbon fiber coated with the ferromagnetic material of the present invention is oriented in a predetermined direction between a semiconductor element and a heat transfer member. The semiconductor device of the invention can be manufactured. In the heat conductive adhesive film of the present invention, since the carbon fibers coated with the ferromagnetic material in the film are already oriented in a certain direction, it is not necessary to apply an external magnetic field at the time of adhesion, but the orientation of the fibers is more maintained. For the purpose, an external magnetic field may be applied at the time of bonding such as heating under pressure. The semiconductor device of the present invention can be manufactured by bonding the semiconductor device and the heat transfer member with a thermally conductive adhesive film in which carbon fibers coated with a ferromagnetic material are oriented in a certain direction. Here, as the heat transfer member, a normal radiator, a cooler, a heat sink,
Examples include a heat spreader, a die pad, a printed circuit board, a cooling fan, a heat pipe, and a housing.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example (Preparation of Carbon Fiber Coated with Ferromagnetic Material) As a carbon fiber coated with a ferromagnetic material, an average diameter of 10 μm was used.
m, average length 80 μm, thermal conductivity 400 W in fiber direction
/ MK pitch-based graphitized carbon fiber D was coated with nickel to a thickness of 0.2 μm by electroless plating to prepare a carbon fiber A coated with a ferromagnetic material. Similarly, Table 1 (FIG. 13)
The carbon fibers B and C were prepared by coating the pitch-based carbon fiber described in (1) with nickel or cobalt as a ferromagnetic material by an electroless plating method.

[0024]

Example 1 45 parts by weight of a bisphenol A type epoxy resin (Epicoat 828 manufactured by Yuka Shell Epoxy), 15 parts by weight of a cresol novolak type epoxy resin (ESCN001 manufactured by Sumitomo Chemical Co., Ltd.), and bisphenol A as a curing agent 40 parts by weight of a novolak resin (manufactured by Dainippon Ink and Chemicals, Inc .: LF2882), 1-cyanoethyl-2-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd .: Cureazole 2PN-C) as a curing accelerator
N) The same weight part of methyl ethyl ketone was added to 80% by volume of an adhesive composition consisting of 1 weight part of an adhesive composition (this is referred to as an epoxy-based solid adhesive). % By volume and kneaded with three rolls, followed by vacuum defoaming. The resulting composition was applied to a thickness of 1
A doctor blade method is applied on a polyethylene terephthalate sheet having a single-sided release treatment of 00 μm, and as shown in FIG. The resultant was dried by heating to prepare a heat conductive adhesive film in a B-stage state having a thickness of 80 μm. The thermal conductivity and the peel strength at 90 degrees in the thickness direction of the obtained thermally conductive adhesive film were measured, and the results are shown in Table 2. Thermal conductivity was measured by the laser flash method. 90 degree peel strength is JISC64
Sandwiched between a copper foil having a thickness of 35 μm and an aluminum plate having a thickness of 1.5 mm according to 71, pressure 2 MPa, 170 ° C.,
The measurement was performed on a sample that was adhered by heating under pressure for 30 minutes.

[0025]

Example 2 30 parts by weight of methyl methacrylate, 40 parts by weight of 2-hydroxyethyl methacrylate, 30 parts by weight of a styrene-based thermoplastic elastomer (Clayton G1650, manufactured by Shell Chemical Co., Ltd.), and Perhexa 3M (manufactured by NOF Corporation) as a curing agent ) A solid adhesive composition comprising 3 parts by weight (this is referred to as an acrylic solid adhesive) 8
A mixed solvent of toluene and methyl ethyl ketone of the same weight part was added to 0% by volume, and then 20% by volume of nickel-coated carbon fiber B as a ferromagnetic material was mixed, kneaded with three rolls, and vacuum defoamed. The obtained composition is 100 μm thick.
Is applied on a polyethylene terephthalate sheet that has been release-treated on one side by a bar coater method, and a magnetic flux density of 60
120 gauss in a magnetic field environment where the north and south poles face each other
The resultant was dried by heating at 20 ° C. for 20 minutes to prepare a heat conductive adhesive film in a B-stage state having a thickness of 80 μm. The thermal conductivity and peel strength at 90 degrees of the obtained thermally conductive adhesive film were measured, and the results are shown in Table 2. The thermal conductivity and the 90-degree peel strength were evaluated in the same manner as in Example 1.

[0026]

Examples 3 to 12 Similarly to Example 1, an epoxy solid adhesive similar to Example 1 or an acrylic solid adhesive similar to Example 2 having the composition shown in Table 2 and a ferromagnetic material A heat conductive adhesive film was produced under the conditions of magnetic flux density shown in Table 2 using a composition comprising carbon fibers coated with. In addition, polyimide of the solid adhesive shown in Table 2 represents a polyimide adhesive, urethane represents a urethane adhesive, and silicone represents an addition type silicone rubber adhesive. The thermal conductivity and the 90-degree peel strength were evaluated in the same manner as in Example 1.

[0027]

Comparative Example 1 A composition comprising 20% by volume of carbon fiber D not coated with a ferromagnetic material in Table 1 and 80% by volume of an epoxy solid adhesive similar to that of Example 1 was used, and a magnetic field was applied. A heat conductive adhesive film was produced in the same manner as in Example 1 except for the above. The thermal conductivity and the 90-degree peel strength were evaluated in the same manner as in Example 1.

[0028]

Comparative Examples 2 to 4 In the same manner as in Comparative Example 1, a composition comprising the same epoxy-based solid adhesive and carbon fiber as in Example 1 having the composition shown in Table 2 was prepared. A heat conductive adhesive film was produced without applying a magnetic field. Thermal conductivity and 9
The 0 degree peel strength was evaluated in the same manner as in Example 1.

[0029]

Embodiment 13 The heat conductive adhesive film 3 of Embodiment 10 of the present invention is used on a ball grid array type semiconductor package 2 mounted on a printed board 1 shown in FIG. 6-1 (FIG. 6-2). As shown in FIG. 6-3, the radiator 4 was arranged on the upper part, and the semiconductor device was heated by pressurizing to produce semiconductor devices FIGS. 6-4 and 6-5. This device was energized and the temperature distribution of the radiator 4 after 2 minutes and 4 minutes was observed with a thermoviewer.

FIG. The temperature difference between the center and the outer edge of the radiator 4 after 10 minutes of energization is 12 ° C., and the temperature at the center is 3
8 ° C. This means that the heat conductive adhesive film interposed between the radiator and the semiconductor package has good heat conductive characteristics.

[0030]

COMPARATIVE EXAMPLE 5 In the same manner as in Example 13, a heat radiator 4 was arranged on a ball grid array type semiconductor package mounted on a printed circuit board using the heat conductive adhesive film 3 of Comparative Example 1 in Table 2 above. The semiconductor device shown in FIG. As in Example 13, the device was energized, and the temperature distribution of the radiator 4 after 2 minutes and 4 minutes was observed with a thermoviewer. The results are shown in FIG. The temperature difference between the center and the outer edge of the radiator 4 after 23 minutes of energization was 23 ° C., and the temperature at the center was 61 ° C. at the maximum.

[0031]

Embodiment 14 As shown in FIGS. 8-1 and 8-2, the heat conductive adhesive film 3 of the embodiment 7 of the present invention is sandwiched between the die pad 7 of the lead frame 6 and the semiconductor chip 8. FIG. The magnetic flux density 20 in the thickness direction by the magnets 12 arranged as shown in FIG.
Heat curing was performed while applying a magnetic field of 00 Gauss. Further, the electrode portion of the semiconductor chip 8 and the lead portion of the lead frame 11 are electrically connected by the bonding wire 9 (FIG.
4) Transfer molding was performed with the epoxy-based sealant 10 to manufacture semiconductor devices shown in FIGS. 8-5 and 8-6. This apparatus was energized, and the change with time of the temperature at the center of the die pad 7 was measured and is shown in FIG. The temperature at the center of the die pad 7 after 52 minutes from the current supply was 52 ° C.

[0032]

Comparative Example 6 As in Example 14, the die pad 7 and the semiconductor chip 8 of the lead frame 6 were cured by heating with the adhesive film 3 of Comparative Example 4. Further, the electrode portion of the semiconductor chip 8 and the lead portion of the lead frame 11 were electrically connected with the bonding wire 9 and transfer-molded with the epoxy-based sealant 10 to manufacture a semiconductor device shown in FIG. This apparatus was energized, and the change with time of the temperature at the center of the die pad 7 was measured and is shown in FIG. The temperature at the center of the die pad 7 after 10 minutes of energization was 65 ° C.

[0033]

As shown in Table 2, the heat conductive adhesive film of the present invention in which the carbon fibers coated with the ferromagnetic material are oriented in a certain direction has good peeling strength, high heat conductivity, and high heat dissipation. Are better. Further, the heat conductive adhesive film of the present invention is applied to the bonding between a semiconductor package having a large amount of heat and a radiator such as a heat sink, or the bonding between a semiconductor chip and a die pad portion to provide a useful semiconductor device having excellent heat radiation characteristics. Can be provided.

[Brief description of the drawings]

FIG. 1 shows an example of a semiconductor device using the heat conductive adhesive film of the present invention (used for bonding a ball grid array type semiconductor package 2 and a radiator 4).

FIG. 2 shows an example of a semiconductor device using the heat conductive adhesive film of the present invention (used for bonding a chip size semiconductor package 2 and a printed circuit board 1).

FIG. 3 shows an example of a semiconductor device using the thermally conductive adhesive film of the present invention (pin grid array type semiconductor package 2).
(Used for bonding heat sink 5)

FIG. 4 shows an example of a semiconductor device using the heat conductive adhesive film of the present invention (used for bonding a semiconductor chip 8 and a die pad 7).

FIGS. 5 (1) to (5) are conceptual diagrams showing a method for producing a heat conductive adhesive film of the present invention, and (6) is a conceptual diagram showing an orientation state of carbon fibers of (5).

FIGS. 6 (1) to (4) are conceptual diagrams showing a method for manufacturing a semiconductor device of the present invention, and (5) is a conceptual diagram showing an orientation state of carbon fibers in (4).

FIG. 7 shows an example of a conventional semiconductor device using a thermally conductive adhesive film containing carbon fibers.

8 (1) to 8 (5) are conceptual diagrams showing a method for manufacturing a semiconductor device of the present invention, and FIG. 8 (6) is a conceptual diagram showing an orientation state of carbon fibers in (5).

FIG. 9 shows an example of a conventional semiconductor device using a thermally conductive adhesive film containing carbon fibers.

FIG. 10 is a diagram showing a temperature distribution during energization of the semiconductor device according to the thirteenth embodiment of the present invention;

FIG. 11 is a diagram showing a temperature distribution during energization of the semiconductor device of Comparative Example 5;

FIG. 12 is a graph showing changes over time in temperature of the semiconductor devices of Example 14 and Comparative Example 6.

FIG. 13 Table 1

FIG. 14 Table 2

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed board 2 Semiconductor package 3 Heat conductive adhesive film 4 Heat sink 5 Heat sink 6 Lead frame 7 Die pad 8 Semiconductor chip 9 Bonding wire 10 Sealant 11 Polyethylene terephthalate sheet 12 Magnet 13 Ferromagnetic coated carbon fiber 14 Conventional Carbon fiber

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kikuo Fujiwara F-term (reference) 4F100 AA23B AB02B AB13B AB14B AB15B AB16B AB31B AD11A AK25A AK33A AK42C AK49A AK51A AK52A AK53A AL09A AR00B BA02 BA03 BA07 BA10A BA10C CB00A DG01A GB41 JB13A JB16A JG04B JG06B JJ01 4J004 AA05 AA10 AA11 AA13 AB05 BA02 4J040 DF021 DM011 EC001 EF001 EH031 EK001 HA026 HA076 HA136 JA09 JB02 KA04 LA08 LA09 NA20 5F036 AA01 BB21 BD21

Claims (7)

[Claims] 1. A heat conductive adhesive film comprising a carbon fiber and a solid adhesive, wherein the carbon fiber coated with a ferromagnetic material is oriented in a certain direction. 2. The heat according to claim 1, wherein the ferromagnetic material is at least one metal, alloy, or compound selected from nickel, iron, ferrite, chromium, cobalt, manganese and rare earths. Conductive adhesive film 3. The heat conduction according to claim 1, wherein the solid adhesive is at least one selected from epoxy, polyimide, acrylic, urethane, vinyl, silicone and thermoplastic elastomer. Adhesive film 4. The heat conductive adhesive film according to claim 1, wherein the solid adhesive is thermosetting and in a semi-cured state. 5. The heat conductive adhesive film according to claim 1, wherein at least one surface is subjected to an electrical insulation treatment. 6. A semiconductor device wherein a carbon fiber coated with a ferromagnetic material is bonded between a semiconductor element and a heat transfer member with a thermally conductive adhesive film oriented in a predetermined direction. 7. The semiconductor according to claim 6, wherein the ferromagnetic material is at least one metal, alloy or compound selected from nickel, iron, ferrite, chromium, cobalt, manganese and rare earths. apparatus