JPH1056114A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat dissipation, miniaturize a cooling structure and reduce its weight, by cooling a semiconductor element by bringing a carbon sheet into contact with a part of the semiconductor element. SOLUTION: On a semiconductor element 3, a heat sink 1 is provided through a carbon (for instance, high orientation graphite) sheet 2. Since heat generated from the semiconductor element 3 is conducted to the heat sink 1 through the carbon sheet 2 having excellent heat conductivity, the semiconductor element 3 is cooled efficiently by heat dissipation. Since heat generated by the semiconductor element 3 is dissipated by the heat sink 1 through the carbon sheet 2 without convecting, heat dissipation characteristic is improved more in the order of graphite fiber, pressed sheet, high orientation graphite, compared with the conventional one which uses aluminum. As for high orientation graphite, heat dissipation characteristic improves as much as 8%. The length of the carbon sheet 2 is permitted to be longer than the semiconductor element 3. Therefore, the carbon sheet 2 operates as a heat dissipation fin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device used for cooling a high-speed semiconductor element used in electronic equipment, industrial equipment, medical equipment, amusement equipment, and the like, and more particularly to a heat dissipation structure.

[0002]

2. Description of the Related Art In recent years, semiconductors have been reduced in size and weight of electronic devices such as personal computers and mobile phones, combined with inspection and measurement technology for industrial devices, downsized, and improved in precision of medical devices.
In order to respond to needs such as multi-functionalization, miniaturization and high-speed operation are inevitable. With such miniaturization and speeding-up, there is a demand for miniaturization, high efficiency, and further weight reduction of a cooling structure for heat generation of a semiconductor. Taking a personal computer as an example, there is a problem that a conventional desktop cooling structure cannot be applied to a notebook computer.

[0003] The conventional semiconductor cooling structure has dealt with such a problem by using a high thermal conductor such as copper or aluminum as a heat sink in a circuit board or a semiconductor package.

[0004]

However, in such a cooling structure, there is a problem that it is not possible to reduce the size and weight of the heat sink from the viewpoint of the weight and the occupied volume of the heat sink. Could not be planned. In addition, since the heat dissipation is insufficient, the high-speed processing by the CPU has a limit, which hinders high performance.
In particular, there has been a problem how to make the close contact between the semiconductor package and the heat sink with a material having good thermal conductivity.

SUMMARY OF THE INVENTION The present invention provides a semiconductor cooling structure which has good heat radiation properties and is further reduced in size and weight.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is to cool a semiconductor element by bringing a carbonaceous sheet into contact with a part of the semiconductor element. Here, the carbonaceous sheet has heat resistance, chemical resistance, and high thermal conductivity, and has a heat conductivity 1.5 to 2.5 times that of conventional copper and 2.5 to 4 times that of aluminum. As a result, high efficiency heat radiation is possible.

Further, by using highly oriented graphite as the carbonaceous sheet, a carbonaceous sheet having high thermal conductivity, excellent flexibility and excellent restoring force can be obtained, and has high efficiency of heat radiation, small size, Weight reduction becomes possible.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION
The semiconductor element is cooled by bringing a carbonaceous sheet such as carbon fiber into contact with a part of the semiconductor element.
Here, the carbonaceous sheet has heat resistance, chemical resistance, and high thermal conductivity, and has a heat conductivity 1.5 to 2.5 times that of conventional copper and 2.5 to 4 times that of aluminum. As a result, high efficiency heat radiation is possible.

According to a second aspect of the present invention, there is provided a semiconductor device in which a carbonaceous sheet is brought into contact with a part of a semiconductor element, and a heat sink with a radiation fan or a Peltier element is brought into contact with the same surface of the carbonaceous sheet. It cools the element, and has a further heat radiation effect as compared with the semiconductor device of the first aspect. According to a third aspect of the present invention, a convex carbonaceous sheet is provided on a part of a semiconductor element, and the carbonaceous sheet itself plays a role of a heat sink. It is effective and can be reduced in size and thickness.

According to a fourth aspect of the present invention, a semiconductor device is installed on an installation table on which a semiconductor element is arranged, and a carbonaceous sheet is provided so as to be in contact with the semiconductor element.
The semiconductor element and a part of the carbonaceous sheet are sealed with resin,
A Peltier element and a heat sink with a fan are provided on the non-resin-sealed carbonaceous sheet. The invention according to claim 5 of the present invention is to directly contact a chip of a semiconductor element such as a bare IC with a carbonaceous sheet via an insulating material such as a thin diamond.
It can be made thinner and can radiate heat from the semiconductor element wafer.

According to a sixth aspect of the present invention, a semiconductor device is provided on a circuit board, a thin film resin is provided on the semiconductor device, and a carbonaceous sheet is adhered to the thin film to form a semiconductor device. The carbonaceous sheet and resin are sealed with resin, and the semiconductor can be reduced in size and thickness, and heat can be radiated from the semiconductor element wafer. A semiconductor that can be processed at high speed can be provided because it can be greatly improved.

According to a seventh aspect of the present invention, a semiconductor device is provided on a circuit board, an insulating layer of diamond or the like is provided on the upper surface of the semiconductor device, and a semiconductor device is sealed on a circuit board around the semiconductor device. The heat dissipation structure of the semiconductor is formed so that the semiconductor element is surrounded by the circuit board, the sealing agent, the insulating layer, and the carbonaceous sheet by stacking the stopper and providing the carbonaceous sheet on the upper surface of the sealing agent and the insulating layer. Thus, a small and highly efficient semiconductor device having an excellent waterproof effect can be provided.

The invention according to claim 8 of the present invention is the invention according to claim 1.
7. In the semiconductor device according to any one of Items 7 to 7, since the carbonaceous sheet is a heat conductive anisotropic sheet, heat can be transmitted with a directivity to a predetermined cooling means, so that there is a further heat radiation effect. According to a ninth aspect of the present invention, in the semiconductor device according to the first to eighth aspects, since the carbonaceous sheet is graphite having a high orientation, it has a high heat radiation property, is easy to process, and has a wide variety of properties. A heat dissipation structure becomes possible.

As the carbonaceous sheet of the present invention, a press-type sheet obtained by pressing a graphite fiber or a natural crystalline graphite powder or by heating with a binder is used. Since these carbonaceous sheets have higher thermal conductivity than copper and aluminum, high-efficiency cooling is possible.

However, a pressed sheet obtained by treating natural crystalline graphite powder does not have a higher thermal conductivity because of the inclusion of impurities, and has a temperature of 90 ° to 180 °.
It was difficult to work because it could be cracked by bending. Further, graphite fibers also contained impurities, so that higher thermal conductivity could not be obtained. In addition, graphite fibers have poor compatibility with heat sinks, so it is necessary to use a heat conductive paste between them, and this heat conductive paste has low thermal conductivity, resulting in low thermal conductivity. .

On the other hand, there is a graphite material having a high degree of orientation (hereinafter referred to as a highly oriented graphite). This graphite material has a high crystallinity in which the orientation direction of the graphite crystal is aligned, and particularly has a locking characteristic of 20 degrees. The following graphite may be used. And
Some of the graphite materials use a material obtained by graphitizing a film of a specific polymer compound, and have good thermal conductivity. Here, the locking characteristic is
The degree of crystal arrangement was determined by measuring the X-ray scattering at the (002) line peak position, which is a plane perpendicular to the graphite thickness direction, using an X-ray diffraction apparatus. .

As the specific polymer compound, various polyoxadiazole (POD), polybenzothiazole (PBT), polybenzobisthiazole (PBBT),
Polybenzoxazole (PBO), polybenzobisoxazole (PBBO), various polyimides (PI), various polyamides (PA), polyphenylene benzimidazole (PBI), polyphenylene benzobisimidazole (PPBI), polythiazole (PT), polypara Phenylene vinylene (PPV), polyamide imide (PA
At least one selected from the group consisting of I) can be used.

The above-mentioned various polyoxadiazoles include:
There are polyparaphenylene-1,3,4-oxadiazole and their isomers. The above-mentioned various polyimides include aromatic polyimides represented by the following general formula (1).

[0019]

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[0020]

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[0021]

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The above various polyamides have the following general formula (2)
There is an aromatic polyamide represented by

[0023]

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The polyimide and polyamide used are not limited to those having these structures. The firing conditions for graphitizing the polymer compound film are not particularly limited, but firing to reach a temperature range of 2000 ° C. or higher, preferably 3000 ° C. or more is preferable because a more excellent orientation can be obtained. . Firing is usually performed in an inert gas. When firing at a maximum temperature of less than 2000 ° C., the obtained graphite tends to be hard and brittle. After the firing, a rolling process may be further performed as necessary.

What is the graphitization of the polymer compound film? For example, it is manufactured by a process of cutting a polymer compound film into an appropriate size, heating the film to 3000 ° C. and graphitizing the film. After firing, a rolling treatment is further performed as necessary. The highly oriented graphite material thus obtained may be in any form of a plate, a sheet, or a film.

An embodiment of a semiconductor cooling structure using a press-type sheet, graphite fiber, or highly oriented graphite as a carbonaceous sheet will be described below.
Here, the heat radiation characteristic is a ratio of a temperature drop ratio of a carbonaceous sheet (here, mainly highly oriented graphite) to a temperature drop ratio of a comparative material (here, mainly aluminum) expressed as a percentage. In the embodiment of
The cooling capacity of the conventional and the present invention will be described using this heat radiation characteristic. For example, when aluminum is used, the surface temperature of the semiconductor element changes from 70 degrees to 65 degrees, and when the carbonaceous sheet is used, the surface temperature of the semiconductor element changes from 70 degrees to 6 degrees.
If it is changed to 0 degrees, the heat radiation characteristic is (70-60) ×
100 / (70-65) (%) = 200%.

Actually, the temperature of the upper surface of the semiconductor element was measured using a temperature measuring element (thermocouple).

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) In a first embodiment of the present invention, a heat sink (here, an aluminum heat sink) 1 is provided on a top surface of a semiconductor element 3 via a carbonaceous sheet 2 as shown in FIG. is there.

With this configuration, the heat generated in the semiconductor is
Since the heat is transmitted to the heat sink through the carbonaceous sheet having good thermal conductivity, the semiconductor element can be radiated and cooled with high efficiency. In this way, the heat generated by the semiconductor element can be radiated by the heat sink through the carbonaceous sheet without being stopped, so that the graphite fiber, the press-type sheet, and the highly oriented graphite radiate in order in comparison with the conventional one using aluminum. The characteristics were improved, and the heat radiation characteristics of the highly oriented graphite were improved by 8%.

Here, the carbonaceous sheet is provided on the upper surface of the semiconductor element, but may be provided at any place such as the lower surface of the semiconductor element where heat can be transferred from the semiconductor. (Embodiment 2) In a second embodiment of the present invention, a heat sink 1 is provided on a top surface of a semiconductor element 3 via a carbonaceous sheet 4 as shown in FIG. It is longer than the semiconductor element 3.

With this configuration, the carbonaceous sheet 4 itself functions as a radiation fin and can radiate heat from both the heat sink 1 and the carbonaceous sheet, so that there is a further cooling effect.
Here, when the highly oriented graphite is used for the carbonaceous sheet, the heat radiation characteristics are 12 times higher than when aluminum is used.
% Improved. Further, in the present embodiment, the length of the carbonaceous sheet is increased. However, the same effect can be obtained if the area of the carbonaceous sheet is made larger than the surface area of the semiconductor element to serve as a radiation fin. Although the carbonaceous sheet is provided on the upper surface of the semiconductor element here, the carbonaceous sheet may be provided at any place such as the lower surface of the semiconductor element where heat can be transferred from the semiconductor.

(Embodiment 3) In a third embodiment of the present invention, a carbonaceous sheet 5 is provided on the upper surface of a semiconductor element 3 as shown in FIG. A heat sink with a radiating fan or a Peltier element 6 is provided on the same surface as the surface. With this configuration,
The heat transmitted from the semiconductor element 3 to the carbonaceous sheet 5 (here, highly oriented graphite) is used as a heat sink with a fan,
The cooling can be forcibly performed by the Peltier element, and a heat radiation characteristic of 30% as compared with conventional copper and 80% as compared with aluminum can be obtained.

Since the heat radiation characteristics are large, sufficient heat conduction is possible with a thickness of less than millimeter, and the specific gravity is 0.37 times that of aluminum and 0.11 times that of copper. It is possible to reduce the size, thickness, and weight. By providing a heat sink with a heat radiating fan or a Peltier element on the same surface of the carbonaceous sheet 5 as the contact surface of the semiconductor element 3, the heat radiating structure can be made thinner.

For this reason, by using such a cooling structure for a semiconductor device (CPU or the like) in a notebook personal computer, it is possible to obtain a small-sized, light-weight, and high-speed one. Further, by performing an insulation treatment on the carbonaceous sheet, heat of the semiconductor element can be transmitted to a heat radiating means such as a Peltier element without loss, and a further heat radiating effect is obtained.

(Embodiment 4) In a fourth embodiment of the present invention, a convex carbonaceous sheet 8 is provided on the upper surface of a semiconductor element 3 as shown in FIG. It plays a role. Specifically, as shown in the figure, by bonding the carbonaceous sheet 8 having a plurality of convex protrusions to the semiconductor element 3 by pressure bonding, it is possible to cool the semiconductor without using a heat sink. Weight reduction becomes possible. Further, as an example, the heat sink can be manufactured by bending a sheet of highly oriented graphite to form a convex protrusion. In this case, the heat radiation characteristics were improved by 11% as compared with the conventional aluminum.

By using a carbonaceous sheet having a fin structure as a heat sink as described above, heat radiation characteristics can be improved. In addition, the carbonaceous sheet 8 and the semiconductor element 3
In order to improve the pressure bonding with the semiconductor element 3, as shown in FIG. 5, a carbonaceous sheet 8 formed of a composite with the semiconductor element 3 with a resin 9 is used to obtain a more effective cooling. Specifically, the heat radiation characteristics are improved by 25% as compared with the conventional case.

(Embodiment 5) In a fifth embodiment of the present invention, as shown in FIG. 8, a bare IC 15 as a semiconductor element is wire-bonded 17 to a mounting table 18 having foot pins 19 as external terminals. A carbonaceous sheet 20 is provided so as to be in contact with the wire bonding 17.
The wire bonding 17, the bare IC 15, and a part of the carbonaceous sheet are sealed with a resin 16, and a Peltier element 6 and a heat sink with fan 7 are provided on a carbonaceous sheet 20 not sealed with the resin. In the present embodiment, two carbonaceous sheets bonded to each other are used. However, one sheet may be used, and any carbonaceous sheet may be used. . In the present embodiment, the semiconductor element and the mounting table are electrically connected by wire bonding. However, the electrical connection may be in any form, and the carbonaceous sheet is connected to wire bonding. The same effect can be obtained even if is connected to a semiconductor element.

Here, in the case where highly oriented graphite is used for the carbonaceous sheet, the heat radiation characteristic before the Peltier element or the like is provided is 50% as compared with the conventional aluminum, and the heat radiation characteristic when the Peltier element or the like is provided is 110%. % Improved. Also, by being able to seal the carbonaceous sheet with the IC with resin,
It is possible to make the device smaller and thinner, and to perform high-speed processing. (Embodiment 6) A sixth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 7, the carbonaceous sheets 25 and 26 (in this embodiment, a two-piece set shown in FIG. 7) are directly applied to a chip which is a bare semiconductor element 31 such as a bare IC via an insulating material 27 such as thin diamond. (Carbonaceous sheet), which allows the semiconductor to be smaller and thinner and can radiate heat from the semiconductor element wafer. A semiconductor that can be processed at high speed can be provided because it can be greatly improved. Here, the chip is an IC or an LSI made to fit on one substrate, and the bare IC is on the ceramic glass substrate 32 in the present embodiment. (Embodiment 7) In a seventh embodiment of the present invention, as shown in FIG. 9, a semiconductor element 22 is disposed on a circuit board 21 by solder 23, and a thin-film epoxy resin is disposed on the semiconductor element. (Here, potting is performed), and the carbonaceous sheets 25 and 26 (in the present embodiment, a set of two carbonaceous sheets shown in FIG. 7) are adhered to the thin film, and the semiconductor element 22 and the carbonaceous sheets 25 and 26 are bonded. It is sealed with an epoxy resin 24.

According to this structure, the semiconductor can be reduced in size and thickness and the heat can be radiated from the wafer of the semiconductor element.
Since it can be greatly improved as compared with a semiconductor packaged with a ceramic package, a semiconductor which can be processed at high speed can be provided. (Eighth Embodiment) An eighth embodiment of the present invention will be described with reference to FIG.
A semiconductor element 22 is disposed on a circuit board 21 as shown in FIG.
0, and a sealing agent 29 is laminated on the circuit board 21 on the outer periphery of the semiconductor element 22, and a carbonaceous sheet 28 is provided on the upper surface of the sealing agent 29 and the insulating layer 30, whereby the semiconductor element 22 Substrate 21, sealant 29, insulating layer 30
Then, a semiconductor device is formed so as to be surrounded by the carbonaceous sheet 28.

Here, the sealing agent includes epoxy resin, silicon and the like. With this configuration, it is possible to obtain a sealing structure similar to the ceramic sealing structure having a higher water absorption rate than conventional potting, and a heat radiation effect twice or more as compared with the conventional one shown in FIG. As a result, a small and highly efficient semiconductor device can be obtained. (Embodiment 9) In the ninth embodiment of the present invention, since the carbonaceous sheet is a heat conductive anisotropic sheet and heat is transmitted with directionality, the heat is actively transmitted to the cooling means. Heat can be efficiently dissipated. In addition, it is possible to suppress transmission of heat to a portion where heat is not desired to be transmitted.

For example, when a heat conductive anisotropic sheet having heat conductive anisotropy in which heat is easily transmitted in the plane direction compared to the thickness direction is used for the carbonaceous sheet 5 of the third embodiment, a heat sink with a heat radiating fan or a Peltier Heat is quickly transmitted to the element,
A lot of heat is cooled by a heat sink with a radiation fan or a Peltier element. Thus, an efficient heat radiation effect can be obtained.

Further, as shown in FIG.
The carbonaceous sheet 10 is bent in a U-shape using a heat conductive anisotropic sheet having heat conduction anisotropy in which heat is easily transmitted in the plane direction compared to the thickness direction.
When the upper surface 10a and the lower surface 10b are connected to the heat sink 1 and the semiconductor element 3, heat is quickly transmitted to the upper surface of the carbonaceous sheet, so that heat can be efficiently radiated from the heat sink 1.

Specifically, the thickness of the aromatic polyimide is 100
A carbonaceous heat conductive anisotropic sheet prepared by heat-treating a polymer film of μm at 3000 ° C. was used.
As shown in FIG. 6B, the sheet was folded in a U-shape, and a plurality of the folded sheets were joined as shown in FIG. 6C to produce a carbonaceous sheet 10. As described above, when the highly oriented graphite is used for the carbonaceous sheet, the heat radiation characteristic is improved by 70% as compared with the conventional aluminum.
As shown in (a) and (b), a plurality of U-shaped bent portions 13 and holes 11 are formed from one carbonaceous sheet 12 by press working, and may be used alone.
Further, by combining two sheets as shown in FIG. 7C, one flat carbonaceous sheet may be formed as shown in FIGS. 7D and 7E.

When the two carbonaceous sheets thus combined are used in place of the carbonaceous sheet 2 shown in FIG. 1, the heat radiation characteristics can be improved by 60% as compared with conventional aluminum. (Embodiment 10) In a tenth embodiment of the present invention, a 100 μm aromatic polyimide film as highly oriented graphite is subjected to a first stage heat treatment at 1200 ° C.
Heat treatment was performed to 3000 ° C.

The carbonaceous sheet thus obtained had a compression ratio of 71.3%, a compression recovery ratio of 76.5%, a thermal conductivity of 700 W / m in the plane direction and 20 W / m in the thickness direction. Was. When this carbonaceous sheet was used as the carbonaceous sheet shown in FIG. 1, the heat radiation property was improved by 8% as compared with conventional aluminum. Further, it is not necessary to use a heat conductive paste or a heat conductive rubber sheet having poor heat conductivity between the heat sink and the semiconductor package as in the related art, so that the heat radiation property of 15% is improved.

Although the present embodiment has been described mainly on the case where highly oriented graphite is used for the carbonaceous sheet, a graphite fiber or a plate type sheet may be used.
However, as mentioned above, both are conventional aluminum,
Although it is superior to copper, the pressed sheet obtained by processing natural crystalline graphite powder does not have higher thermal conductivity because it contains impurities, it is a bond of carbon powder, When the sheet is brittle and an external load such as bending or bending is applied, or when processing is required, the sheet may be damaged. Further, graphite fibers also contained impurities, so that higher thermal conductivity could not be obtained. In addition, graphite fibers have poor compatibility with heat sinks, so it is necessary to use a heat conductive paste between them, and this heat conductive paste has low thermal conductivity, resulting in low thermal conductivity. Therefore, it is preferable to use highly oriented graphite. For this reason, the press-type sheets of Embodiments 1 and 2 and the carbon fibers of Embodiments 1, 2, 3, 5, and 6 will be practically possible.

[0047]

As described above, the present invention cools a semiconductor element by bringing a carbonaceous sheet such as graphite fiber into contact with a part of the semiconductor element. In addition, since the carbonaceous sheet is a heat conductive anisotropic sheet and transmits heat in a directional manner, heat can be positively transmitted to the cooling means, and heat can be efficiently radiated.

Further, since the carbonaceous sheet is made of graphite having a high orientation, it has a high heat dissipation property and can be easily processed, so that various heat dissipation structures can be realized.

[Brief description of the drawings]

FIG. 1 is a view showing a semiconductor device according to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating a semiconductor device according to a second embodiment of the present invention;

FIG. 3 is a diagram showing a semiconductor device according to a third embodiment of the present invention;

FIG. 4 is a diagram showing a semiconductor device according to a fourth embodiment of the present invention;

FIG. 5 is a diagram showing a semiconductor device in the embodiment.

FIG. 6 is a diagram showing a semiconductor device according to a ninth embodiment of the present invention;

FIG. 7 is a diagram showing a semiconductor device in the embodiment.

FIG. 8 is a diagram showing a semiconductor device according to a fifth embodiment of the present invention.

FIG. 9 shows a semiconductor device according to a seventh embodiment of the present invention.

FIG. 10 is a diagram showing a semiconductor device according to a sixth embodiment of the present invention.

FIG. 11 is a diagram showing a semiconductor device according to an eighth embodiment of the present invention.

FIG. 12 is a view showing a conventional resin-encapsulated semiconductor;

[Explanation of symbols]

1 Heat sink 2, 4, 5, 8, 10, 12, 14, 20, 25, 2
6, 28 Carbonaceous sheet 3 Semiconductor element 6 Peltier element 7 Heat sink with fan 10 Resin material

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Tsutomu Kawashima 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (9)

[Claims] 1. A semiconductor device wherein a carbonaceous sheet is brought into contact with a part of a semiconductor element. 2. A semiconductor device wherein a carbonaceous sheet is brought into contact with a part of a semiconductor element, and a heat sink with a radiation fan or a Peltier element is brought into contact with the carbonaceous sheet. 3. A semiconductor device in which a carbonaceous sheet having a fin structure is brought into contact with a semiconductor element. 4. A semiconductor device is installed on a mounting table on which a semiconductor element is arranged, and a carbonaceous sheet is provided so as to be in contact with the semiconductor element. A semiconductor device in which a Peltier element and a heat sink with a fan are provided on the carbonaceous sheet that is not resin-sealed. 5. A semiconductor device in which a chip of a semiconductor element is brought into direct contact with a carbonaceous sheet via a thin insulating material. 6. A semiconductor element is disposed on a circuit board, a thin film resin is disposed on the semiconductor element, a carbonaceous sheet is adhered to the thin film, and the semiconductor element and the carbonaceous sheet are sealed with the resin. Semiconductor device. 7. A semiconductor device is provided on a circuit board, an insulating layer such as diamond is provided on an upper surface of the semiconductor device, and a sealant is laminated on the circuit board around the semiconductor device to seal the semiconductor device. A semiconductor device in which a semiconductor element is surrounded by a circuit board, a sealant, an insulating layer, and a carbonaceous sheet by providing a carbonaceous sheet on top of an agent and an insulating layer. 8. The semiconductor device according to claim 1, wherein
A semiconductor device in which the carbonaceous sheet is a heat conductive anisotropic sheet. 9. The semiconductor device according to claim 1, wherein
A semiconductor device in which the carbonaceous sheet is graphite having high orientation.