JP2003273294A - Thermal conductive sheet and semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal conductive sheet which, even at low pressure whereby a large-sized semiconductor element is hard to crack, can be adhered properly to the semiconductor element and a radiator plate to obtain excellent thermal conductivity, and to provide a semiconductor device using the sheet. <P>SOLUTION: In a thermal conductive sheet 1, a plurality of metal projections 3 are disposed on at least one surface of metal foil 2, and at least a part of clearances between the plurality of metal projections 3 is filled with a resin 4, and the resin 4 is heated and/or pressurized to be melted and/or to be made to flow, thereby having an adhesion function. In a semiconductor device 7, at least a semiconductor element 5 and a radiator plate 6 are adhered to the thermal conductive sheet 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat conductive sheet that efficiently transfers heat generated in a semiconductor element to a heat dissipation plate (heat dissipation plate, heat spreader, etc.), and a semiconductor device incorporating the same.

[0002]

2. Description of the Related Art With the increase in density and performance of semiconductor elements, the influence of heat generated from the semiconductor elements has become a factor that narrows the degree of freedom in designing semiconductor devices and electronic equipment incorporating the semiconductor devices. There is. As one means for reducing the influence of such heat, there is a method of efficiently transmitting the heat generated from the semiconductor element during operation to the heat dissipation plate outside the semiconductor element via the heat conductive sheet. By such a method, it is expected that the semiconductor element is prevented from being heated to a high temperature and the high temperature operation failure is reduced.

As a conventional heat-conducting sheet, there is described a heat-dissipating sheet (heat-conducting sheet) obtained by laminating a cured product of a silicone resin composition containing a heat-conducting substance on one side or both sides of a metal foil ( See Patent Document 1). Although the sheet has excellent adhesion to a semiconductor element, it does not have sufficient heat conductivity and is not suitable for use in a highly densified semiconductor element that generates a large amount of heat.

As another conventional technique, the present inventors have proposed to use an anisotropic conductive film as a heat conductive sheet (see Patent Document 2). The heat conductive sheet was superior in heat conductivity to the heat conductive sheet described in JP-A-6-291226. However, the anisotropic conductive film does not have sufficient adhesion to the semiconductor element. Therefore, when the semiconductor element is large (for example, one side is 10 mm or more), when pressure is applied at the time of bonding, stress concentration due to the warp of the semiconductor element occurs and the semiconductor element is broken. .

[0005]

[Patent Document 1] JP-A-6-291226

[Patent Document 2] Japanese Patent No. 3179503

The problem of the warp of the semiconductor element becomes apparent in the case of a large semiconductor element having one side of 10 mm or more. The degree of warpage of the semiconductor element varies depending on the type of device, the size of the semiconductor element, and the thickness of the semiconductor element, but a semiconductor element having one side of 20 mm may warp about 150 μm. When a semiconductor element having a warp and a heat dissipation plate are bonded by pressure via a heat conductive sheet (heat dissipation sheet), stress of the pressure is concentrated, and the semiconductor element may be broken. Therefore, the applied pressure is 1MP
It is preferably a or less, usually about 0.5 MPa. Therefore, since it can be used for a large-sized semiconductor element, even with such a low pressure, sufficient adhesiveness can be obtained between the semiconductor element and the heat conductive sheet and between the heat dissipation plate and the heat conductive sheet. There has been a demand for a heat conductive sheet that can obtain

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a semiconductor element and a heat sink even when the pressure is such that a large semiconductor element is hard to crack. An object is to provide a heat conductive sheet that is well adhered to a plate and that has good heat conductivity.

[0008]

The present invention has the following features. (1) A plurality of metal protrusions are arranged on at least one surface of the metal foil, and at least a part of the gaps between the metal protrusions is filled with resin, and the resin is heated and / or heated.
Alternatively, a heat conductive sheet having an adhesive function by being melted and / or fluidized by applying pressure. (2) The heat-conducting sheet according to (1), in which a plurality of metal protrusions are arranged on both front and back surfaces of the metal foil. (3) The heat conductive sheet according to (1) or (2), wherein the metal protrusions are made of a metal that softens at 150 ° C. to 300 ° C. and forms a metal bond with another metal. (4) The heat conductive sheet according to any one of (1) to (3), wherein the shape of each of the metal protrusions is a cylinder, a square pole, or a sphere. (5) 20% to 75% of the total surface area of the front and back surfaces of the metal foil
%, The metal protrusions are arranged in the area of
The heat conductive sheet according to any one of (1) to (4). (6) A semiconductor device in which at least a semiconductor element and a heat dissipation plate are bonded via the heat conductive sheet according to any one of (1) to (5). (7) The semiconductor device according to (6), wherein the heat radiating plate is made of metal, and at least a part of the plurality of metal protrusions forming the heat conductive sheet are metal-bonded to the heat radiating plate.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The heat conductive sheet and the semiconductor element according to the present invention will be described below with reference to the drawings.
The invention is not limited to the embodiments shown in the drawings. As shown in FIG. 1, the heat conductive sheet 1 according to the present invention.
Has at least a metal foil 2, a metal protrusion 3, and a resin 4. These will be sequentially described.

1. Metal Foil A metal foil 2 known in the art can be used for the heat conductive sheet 1 according to the present invention, but a copper foil is preferably used. This is because the metal convex 3 to be described later can be easily processed. That is, the metal protrusion 3 is usually
This is because it is formed by plating or etching, but by using a copper foil as the metal foil 2 at this time, the conventional process can be easily utilized.

The thickness of the metal foil 2 is usually selected in the range of 10 μm to 100 μm from the viewpoint of availability, cost, etc., but it is easy to handle when forming the metal protrusions 3, and the metal foil 2 20 μm to 70 μm is preferable, and 30 μm to 40 μm in consideration of its own (following deformation) followability.
Is more preferable.

By combining the metal foil 2 with the metal convex 3 which will be described later, it is important in that the heat conductive sheet 1 according to the present invention has remarkably excellent heat conductivity as compared with the conventional heat conductive sheet. Play a role. The action mechanism that fulfills this role will be described in detail in the description of the metal protrusion 3 described later.

2. A plurality of metal protrusions 3 are arranged on at least one surface of the metal foil 2, preferably both front and back surfaces.

When the heat conductive sheet 1 according to the present invention is used, as shown in FIG. 3, a semiconductor element (that is, a heating element) is used.
5 and / or the surface of the heat dissipation plate 6, the metal projection 3
The surface of the apex of is directly contacted, and heat can be efficiently transferred. Specifically, the heat generated from the semiconductor element 5 is transferred to the metal foil 2 via the metal protrusion 3 that is in contact with the semiconductor element 5.
Is spread to the entire surface of the metal foil 2. Then, heat is transferred from the metal foil 2 to the heat dissipation plate 6 over the entire surface. This allows
The heat radiating plate 6 against the local heat generation in the semiconductor element 5.
Heat can be efficiently dissipated to the entire surface. As described above, the heat conductive sheet 1 according to the present invention includes the metal foil 2 and the metal protrusions 3.
By having both of them, it is possible to exhibit significantly higher thermal conductivity than the conventional thermal conductive sheet, and to improve the followability to the warp of the semiconductor element 5 (derived from the metal foil 2).

In view of the above operation, the metal convex 3 is
The metal foil 2 is preferably arranged not only on one side but on both sides. However, it may be arranged on only one side of the metal foil 2 in consideration of the heat generation of the semiconductor element 5, the cost, and the like.

The shape of the metal protrusion 3 is not particularly limited,
For example, it is selected from a spherical shape, a cylindrical shape, a conical shape, a quadrangular prism shape, a cubic shape, and the like, and the spherical shape or the cylindrical shape is preferable from the viewpoint of thermal conductivity, workability, and contact stability. Here, the term "spherical" means not only a perfect sphere but also a part of the metal convex 3 is spherical (eg, the metal convex 3 is hemispherical, the tip of the metal convex 3). If only the curved surface).
When the metal protrusion 3 has a columnar shape or a quadrangular prism shape, its thickness (diameter or length of one side) and pitch (distance between the centers of the adjacent metal protrusions 3) are determined by followability with the contact surface. In order to obtain Φ (or □), the pitch is usually 0.05 to 0.9, and the pitch is 0.07 mm to 1 mm. .0
5 to 0.5 and the pitch is 0.07 mm to 0.6 mm
Is preferred. In the present specification, JIS Z83
17, "φ" is the diameter of the circle, and "□" is the square
The length of each side is used as a symbol representing each millimeter. If the height of the metal convex 3 is too low, the followability to the height difference due to the warp or roughness of the heat generating surface (that is, the semiconductor element 5) and the heat radiating surface (that is, the heat radiating plate 6) decreases, and If it is too much, the thermal resistivity becomes high, so it is usually 10 μm to 150 μm, preferably 50 μm to 70 μm.
The range is m.

The method for forming the metal protrusion 3 is not particularly limited, and a process conventionally used for a printed circuit board or the like may be used. As a specific example, the surface of the metal foil 2 is selectively removed by, for example, etching to form the metal protrusions 3, or the metal foil 2 is selectively plated. Examples thereof include a process of forming the metal protrusions 3, a process of arranging a paste-like fluid containing solder or the like by screen printing, and the like. In forming the metal protrusion 3 by plating, nickel plating, tin plating, copper plating, gold plating, solder plating or the like is selected. Considering the followability to the warp of the semiconductor element 5, tin plating, gold plating, and solder plating, which can be easily deformed against pressure, are preferable.

As a more preferable embodiment of the material of the metal protrusion 3, a metal (solder, tin, etc.) that can be softened at 150 ° C. to 300 ° C. and can be metal-bonded to another metal can be mentioned.
Here, the “other metal” is not particularly limited as long as it is a metal that can be used for the heat dissipation plate 6 described later, and examples thereof include copper and nickel. When the heat conductive sheet 1 having the metal protrusions 3 made of such a material and the metal heat dissipation plate 6 are used, they are heated (and if necessary, pressed) between them. A metallurgical bond can be formed. Here, the metal joining means fusion joining, and is joining realized by general welding or the like. In metal bonding, it is sufficient that at least the metal protrusion 3 is melted, and the heat dissipation plate 6 may or may not be melted. As a typical example of metal joining, joining of heat-softened solder and metal can be mentioned. Thus, by forming the metal joint, the heat dissipation plate 6 and the heat conductive sheet 1 are formed.
By improving the contact property with, it is possible to further improve the heat conduction efficiency.

The metal protrusions 3 preferably occupy 20% to 75% of the surface area of the metal foil 2 (total of both front and back surfaces), and more preferably 35% to 50%. This is because the thermal conductivity improves as the proportion of the metal protrusions 3 increases, and the deformation such as the warp of the semiconductor element 5 tends to follow as the proportion of the metal protrusions 3 decreases.

3. The resin 4 put in the gap between the resin-metal convexes 3 is a thermosetting resin or a thermoplastic resin, and has a bonding function by being melted and / or fluidized by heating and / or pressurizing. Here, heating and / or pressurization means heating to 70 ° C. to 250 ° C. and / or 0.5.
It means applying a pressure of MPa to 1.0 MPa, and having an adhesive function means being able to adhere to other solids (that is, the semiconductor element 5 and the heat dissipation plate 6). By using such a resin 4, as a result, the resin 4 can be bonded to the semiconductor element 5 and the heat sink 6 with a low pressure, and it is expected that the semiconductor element is prevented from being damaged. If the adhesive force of the resin 4 is sufficient, the pressure contact is not necessary, but if it is not, the pressure contact may be applied by using a clamp arranged between the semiconductor element and the heat dissipation plate.

Specific examples of the resin 4 used in the present invention include:
Examples thereof include thermoplastic polyimide resin, epoxy resin, polyetherimide resin, polyamide resin, silicone resin, phenoxy resin, acrylic resin, polycarbodiimide resin, fluororesin, polyester resin, polyurethane resin and the like.

As a method of inserting the resin 4 into the gaps between the metal protrusions 3, a liquid resin 4 having a low viscosity and fluidity is applied, and a squeegee or the like is used to remove the resin 4 from the top surface of the metal protrusions 3. A method of scraping off the upper resin 4 and leaving the resin 4 only in the gap, or a sheet-like resin having a volume sufficiently filled in the gap of the metal convex 3 is inserted into the gap and heated and / or pressurized Thus, the resin 4 is melted and / or flowed so that the metal convex 3 penetrates the resin 4 and is brought into contact with the semiconductor element 5 and / or the heat dissipation plate 6, and further the resin 4 is applied to the semiconductor element 5 and / or Although the method of adhering to the heat sink 6 is mentioned, it is not limited to these.

The resin 4 may fill all the gaps of the plurality of metal protrusions 3 as shown in FIG. 1, or may fill part of the gaps as shown in FIG. . However,
In the heat conductive sheet 1, it is preferable that all the gaps on the surface to be bonded to the semiconductor element 5 are filled with resin from the viewpoint of improving the adhesiveness. On the other hand, regarding the surface to be bonded to the heat dissipation plate 6, for example, when the metal convex 3 and the heat dissipation plate 6 are metal-bonded as described above, sufficient adhesiveness (bondability) is often obtained. Therefore, the resin 4 does not necessarily have to be filled.

The heat conductive sheet 1 obtained as described above
And the semiconductor element 5 and the heat sink 6 are bonded to each other, for example,
This is achieved by using a known device used for bonding such as a flip chip bonder. In this way, as shown in FIG. 3, the semiconductor device 7 in which the semiconductor element 5 and the heat dissipation plate 6 are bonded via the heat conductive sheet 1 can be obtained. The semiconductor device 7 includes elements other than the heat conductive sheet 1, the semiconductor element 5 and the heat dissipation plate 6 (heat sink,
The heat radiation fan or the like) may be further included.

The shape and size of the semiconductor element 5 are not particularly limited, but the present invention can be applied to a large-sized semiconductor element 5 which is difficult to apply a conventional heat conductive sheet or the like and is easily broken by pressure. The heat conductive sheet 1 can be easily applied. Here, the large size of the semiconductor element 5 means that the area is 1
00 mm ² or more (for example, a square having one side of 10 mm or more, preferably a square having one side of 15 to 25.4 mm).

[0026]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the examples.

(Example 1) 15 m long as the metal foil 2
m, width 15 mm, thickness 70 μm electrolytic copper foil (Super HTE manufactured by Mitsui Kinzoku Kogyo) 0.47 m in diameter on both sides
m, a pitch of 0.6 mm, and a depth of 20 μm were subjected to an etching treatment to form a cylindrical metal protrusion 3 (bump).
By this treatment, 49% of the total surface area of the metal foil 2 was occupied by the metal protrusions 3. Polycarbodiimide resin 4 (thermosoftening temperature 120 ° C., base concentration 32%, diluted with toluene), which is a thermoplastic resin, is flowed in the gap between the bumps,
The surface was scraped off with squeegee to fill the gaps between the bumps, and then heated at 120 ° C. for 1 minute to cure. After that, the bump surface was exposed from the resin 4 by precision polishing to obtain a heat conductive sheet 1. Then, as shown in FIG. 3, a heat spreader (made of copper, thickness 1.5 m
m, 20 mm square) and the semiconductor element 5 (15 mm square) sandwiching the heat conductive sheet 1, and 230 ° C., 0.5 MP
a, heating and pressure were applied for 20 seconds.

When the thermal resistivity of the heat conductive sheet 1 itself was calculated from the measurement of the temperature difference Δt between the heat generation temperature of the semiconductor element 5 in the initial state and the transfer temperature to the heat spreader surface,
It was 0.12 cm ² K / W. After that, thermal shock test (125 ° C / -55 ° C, 30 minutes / 30 minutes, 1 cycle)
Was carried out for 1000 cycles, Δt was measured again, and the thermal resistivity was calculated. As a result, it was 0.13 cm ² K / W, and there was no change before and after the thermal shock test.

(Example 2) 20 m in length as the metal foil 2
m, width 20 mm, thickness 35 μm copper foil (Super HTE manufactured by Mitsui Kinzoku Kogyo Co., Ltd.) was subjected to half-etching treatment of 0.2 mm square, pitch 0.4 mm, and depth 20 μm on one side to form a rectangular columnar metal convex 3 ( Bumps) were formed. In addition, pattern solder (Pb /
Sn eutectic solder) plating to form a square metal protrusion 3 having a square shape of 0.2 mm square, a pitch of 0.4 mm, and a height of 20 μm.
(Convex bump) was formed. By this treatment, the metal foil 2
25% of the total surface area of the metal convex 3 was to be occupied. The copper foil, the heat dissipation plate 6 (heat spreader) and the semiconductor element 5 similar to those in Example 1 were bonded as shown in FIG. 3 so that the bumps formed by half etching and the semiconductor element 5 were in contact with each other. At the time of bonding, an adhesive sheet made of polycarbodiimide resin 4 (heat softening temperature 150 ° C.) having a side of 15 mm and a thickness of 10 μm is sandwiched between the semiconductor element 5 and the copper foil and between the copper foil and the heat spreader. The sample was heated and pressurized at 200 ° C., 0.5 MPa, 20 seconds.

Thereafter, as in the first embodiment, the semiconductor element 5
The temperature difference Δt between the heat spreader and the heat spreader was measured, and the thermal resistivity was calculated to be 0.08 cm ² K / W.
Further, the same thermal shock test as in Example 1 was carried out for 1000 cycles, Δt was measured again, and the thermal resistivity was calculated to be 0.09 cm ² K / W, which was unchanged before and after the thermal shock test. .

(Embodiment 3) The copper foil on which bumps are formed in Embodiment 2 is replaced with a heat spreader (made of copper, gold-plated on the surface, thickness 1.5 mm, 20 mm square) as the heat dissipation plate 6 and the semiconductor element 5 (Embodiment 1). (The same dimension as the above), and heated and pressed at 235 ° C., 0.5 MPa and 20 seconds for bonding so that the bump formed by half etching and the semiconductor element are in contact with each other. At this time, the same adhesive sheet as in Example 2 was sandwiched and bonded only between the semiconductor element 5 and the copper foil, and between the heat spreader and the copper foil, the bump and the heat spreader were metal-bonded without the adhesive sheet. Let

Thereafter, as in the first embodiment, the semiconductor element 5
The temperature difference Δt between the heat spreader and the heat spreader was measured, and the thermal resistivity was calculated to be 0.05 cm ² K / W.
Further, the same thermal shock test as in Example 1 was carried out for 1000 cycles, Δt was measured again, and the thermal resistivity was calculated to be 0.05 cm ² K / W, which was unchanged before and after the thermal shock test. .

(Embodiment 4) Metal foil 2 having a length of 15 m
m, width 15 mm, thickness 70 μm rolled copper foil (Japan foil TCU-O-70), one side of which was subjected to etching treatment with a diameter of 0.47 mm, a pitch of 0.6 mm and a depth of 30 μm to form a cylindrical metal projection. Form 3 (bumps) was formed. At the same position as the bump on the other side of this copper foil (just behind),
Solder bumps having the same diameter and pitch height of 100 μm as above were formed. By this treatment, 49% of the total surface area of the metal foil 2 was occupied by the metal protrusions 3. Then
A polycarbodiimide resin (heat softening temperature 120 ° C., base concentration 32%, diluted with toluene), which is a thermoplastic resin, is flowed on the surface of the copper foil on which the bumps are formed by etching.
The surface was scraped off with squeegee to fill the gaps between the bumps, and then heated at 120 ° C. for 1 minute to cure. After that, the bump surface was exposed from the resin 4 by precision polishing to obtain a heat conductive sheet 1. A heat spreader (made of copper, thickness 1.5 m
m, 20 mm square) and the semiconductor element 5 (same dimensions as in Example 1), and thermocompression bonding was performed at 240 ° C., 0.5 MPa, 20 seconds. At this time, the bumps formed by etching and the semiconductor element 5 were bonded so that they were in contact with each other. The bump and the heat spreader were metal-bonded between the heat spreader and the copper foil (the surface on which the solder bump was formed).

Then, as in the first embodiment, the semiconductor element 5
The temperature difference Δt between the heat spreader and the heat spreader was measured, and the thermal resistivity including the contact resistance was calculated to be 0.12 cm ²
It was K / W. Further, the same thermal shock test as in Example 1 was carried out for 1000 cycles, Δt was measured again, and the thermal resistivity was calculated to be 0.13 cm ² K / W, which was unchanged before and after the thermal shock test. .

(Example 5) 20 m in length as the metal foil 2
m, width 20 mm, thickness 35 μm rolled copper foil (Japan foil TCU-O-35) on both front and back sides by screen printing 0.43 mm square, pitch 0.6 mm, height 10
A metal protrusion 3 (Pb / Sn eutectic solder bump) having a square pillar shape of 0 μm was formed. The positions of the bumps were the same on the front and back. By this treatment, 61% of the total surface area of the metal foil 2
The metal convex 3 is occupied. A solder resist was laminated on one side of the metal foil 2, and an adhesive sheet made of polycarbodiimide resin 4 (heat softening temperature 150 ° C.) and having a thickness of 10 μm was attached to the opposite side. afterwards,
The heat conduction sheet 1 was obtained by exposing the bump surface from the resin 4 by precision polishing with a plane. A heat spreader (made of copper, thickness 1.5 m
m, 20 mm square) and the semiconductor element 5 (same dimensions as in Example 1), and thermocompression bonding was performed at 240 ° C., 0.5 MPa, 20 seconds. At this time, the bonding was performed so that the surface on which the adhesive sheet was bonded and the semiconductor element 5 were in contact with each other. Such adhesion improves the ability of the solder bump to follow the semiconductor element surface. The heat spreader and the solder bump were metal-bonded.

Thereafter, as in the first embodiment, the semiconductor element 5
The temperature difference Δt between the heat spreader and the heat spreader was measured, and the thermal resistivity including the contact resistance was calculated to be 0.08 cm ²
It was K / W. Further, the same thermal shock test as in Example 1 was carried out for 1000 cycles, Δt was measured again, and the thermal resistivity was calculated to be 0.09 cm ² K / W, which was unchanged before and after the thermal shock test. .

(Comparative Example 1) Highly thermally conductive filler (alumina) was added to a commercially available silicone resin in a volume ratio of 70%.
The filled heat conductive sheet (thickness 0.5 mm) was sandwiched between the semiconductor element and the heat spreader as shown in Example 1. Then, the whole was heated and pressurized at 160 ° C. and 0.5 MPa for 3 seconds. The temperature difference Δt between the semiconductor element and the heat spreader in the initial state was measured, and the thermal resistivity was determined to be about 1.5 cm ² K / W. The thermal conductive sheet was significantly inferior in thermal conductivity to the thermal conductive sheets of Examples 1 to 3.

(Comparative Example 2) A commercially available silicone resin is filled with 80% by weight of ultrafine particle filler of silicon nitride, and a thermally conductive paste having a thickness of about 0.1 mm is used to cope with warpage of a semiconductor element. And the paste was sandwiched between the semiconductor element and the heat spreader. The result of measuring the thermal resistance by measuring Δt in the initial state is 0.15c
It was about m ² K / W. Thereafter, when the same thermal shock test as in Example 1 was carried out for 1000 cycles, it was observed that the paste had flowed out. In addition, Δt
Was measured and the thermal resistance was calculated, the thermal resistance was 0.6 c
It was about m ² K / W, which resulted in deterioration of thermal conductivity.

[0039]

EFFECTS OF THE INVENTION The heat conductive sheet 1 of the present invention (1) easily follows deformation such as warpage of the semiconductor element 5 due to having the resin 4 and the metal foil 2, and (2) the resin. 4 has an adhesive function by heating and / or pressurization, so that the adhesiveness to the semiconductor element 5 and the heat sink 6 is improved,
(3) Heat can be efficiently conducted due to the presence of the metal protrusions 3, and (4) heat locally generated due to the presence of the metal foil 2 can be spread over the entire surface. Therefore, the heat conductive sheet 1 of the present invention has the effects of (1) and (2) above.
Even when bonded to a large-sized semiconductor element 5, the semiconductor element 5 can be bonded at a low pressure such that the semiconductor element 5 is unlikely to break, and
Due to the effects of (3) and (4), the heat generated during the operation of the semiconductor element 5 can be efficiently conducted to the heat dissipation plate 6 after the bonding.
In a preferred embodiment of the present invention, the metal convex 3
Since the heat radiation plate 6 and the heat radiation plate 6 can be metal-bonded to each other, the adhesiveness (bondability) and thermal conductivity can be further improved. The semiconductor device 7 having such a heat conductive sheet 1 can reduce the problem of heat generated from the semiconductor element 5. Therefore, by using the semiconductor device 7 according to the present invention, it is expected that the degree of freedom in circuit design of electronic equipment will be expanded.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an embodiment of a heat conductive sheet according to the present invention. (A) is a cross-sectional view showing the thickness direction of the sheet, and (B) and (C) are respectively I of (A).
And Figure 2 is a schematic view of the sheet from the direction of II.

FIG. 2 is a diagram schematically showing an embodiment of a heat conductive sheet according to the present invention. (A) is a cross-sectional view showing the thickness direction of the sheet, and (B) and (C) are respectively I of (A).
And Figure 2 is a schematic view of the sheet from the direction of II.

FIG. 3 is a diagram showing an outline of a semiconductor device according to the present invention.

[Explanation of symbols]

1 Thermal conductive sheet 2 metal foil 3 Metal convex 4 resin 5 Semiconductor element 6 heat sink 7 Semiconductor device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuji Hotta             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. F-term (reference) 5F036 AA01 BA04 BB21 BD21

Claims (7)

[Claims] 1. A plurality of metal projections are arranged on at least one surface of a metal foil, and a resin fills at least a part of a gap between the plurality of metal projections, and the resin is heated and / or heated. A heat conductive sheet having an adhesive function by being melted and / or fluidized by applying pressure. 2. The heat conductive sheet according to claim 1, wherein a plurality of metal protrusions are arranged on both front and back surfaces of the metal foil. 3. The metal convex product is 150 ° C. to 300 ° C.
The heat conductive sheet according to claim 1 or 2, which is made of a metal that is softened by and is metal-bonded to another metal. 4. The shape of each of the metal protrusions is a cylinder,
The heat conductive sheet according to any one of claims 1 to 3, which has a quadrangular prism shape or a spherical shape. 5. The total surface area of both sides of the metal foil is 20
The heat conductive sheet according to any one of claims 1 to 4, wherein the metal protrusions are arranged in a region having an area of% -75%. 6. A semiconductor device in which at least a semiconductor element and a heat dissipation plate are bonded to each other via the heat conductive sheet according to claim 1. 7. The semiconductor device according to claim 6, wherein the heat dissipation plate is made of metal, and at least a part of the plurality of metal projections forming the heat conductive sheet are metal-bonded to the heat dissipation plate. .