JP2017092345A - Heat conduction sheet and method of manufacturing the same, and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat conduction sheet and the like capable of improving an adhesion property to a heat source and a heat radiation member, and that is excellent in thermal conductivity and electrical insulation properties.SOLUTION: A heat conduction sheet has, in this order, a thermal conductive filler containing layer that contains a binder resin and a thermal conductive filler, a first adhesive layer that contains a first adhesive agent, an insulation resin layer that contains an insulation resin and that has an insulation property, and a second adhesive layer that contains a second adhesive agent. A surface of the thermal conductive filler containing layer is covered with an exudation component exuded from the thermal conductive filler containing layer so as to follow a convex shape by the protruded the thermal conductive filler.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat conductive sheet disposed between a heat source such as a semiconductor element and a heat radiating member such as a heat sink, a manufacturing method thereof, and a semiconductor device including the heat conductive sheet.

  Conventionally, in semiconductor devices mounted on various electric devices such as personal computers and other devices, heat is generated by driving, and when the generated heat is accumulated, driving of the semiconductor devices and peripheral devices are adversely affected. Therefore, various cooling means are used. As a method for cooling electronic components such as semiconductor elements, there are a method in which a fan is attached to the device and the air in the device casing is cooled, and a method in which a heat sink such as a heat radiation fin or a heat sink is attached to the semiconductor device to be cooled Are known.

  When a semiconductor device is cooled by attaching a heat sink, a heat conductive sheet is provided between the semiconductor device and the heat sink in order to efficiently release the heat of the semiconductor device. As the thermal conductive sheet, a silicone resin in which fillers such as boron nitride (BN), scaly particles such as graphite, and a thermal conductive filler such as carbon fiber are dispersed and contained is widely used (for example, patents). Reference 1).

  These heat conductive fillers have anisotropy of heat conduction. For example, when carbon fiber is used as the heat conductive filler, a heat of about 600 W / m · K to 1200 W / m · K in the fiber direction. When boron nitride is used, it has a thermal conductivity of about 110 W / m · K in the plane direction and about 2 W / m · K in the direction perpendicular to the plane direction. It is known to have.

  Here, electronic parts such as a CPU of a personal computer tend to increase in heat dissipation year by year as the speed and performance thereof increase. However, on the contrary, the chip size of a processor or the like has become equal to or smaller than the conventional size due to the advancement of fine silicon circuit technology, and the heat flow rate per unit area is high. Therefore, in order to avoid problems caused by the temperature rise, it is required to more efficiently dissipate and cool electronic components such as CPUs.

  In order to improve the heat dissipation characteristics of the heat conductive sheet, it is required to lower the thermal resistance, which is an index indicating difficulty in transferring heat. In order to reduce the thermal resistance, it is effective to improve the adhesion to an electronic component as a heat source and a heat radiating member such as a heat sink.

  It is a factor which reduces adhesiveness that the heat conductive fillers, such as carbon fiber, are exposed to the sheet | seat surface (for example, refer patent document 2). In that case, the followability and adhesion to the heat source and the heat radiating member are poor, and the thermal resistance cannot be lowered sufficiently. Moreover, in order to immerse the thermally conductive filler in the sheet, a method of sandwiching the thermally conductive sheet with a high load between the heat source and the heat radiating member has been proposed (see, for example, Patent Document 3). When it is used for a heat source for which heat resistance is required, the heat conductive filler is not immersed and the thermal resistance cannot be lowered.

  On the other hand, the heat conductive sheet is required to have electrical insulation in order to prevent short-circuiting of electronic components. However, if the heat conductive filler is present on the surface of the heat conductive sheet, there is a problem that the electric insulation is not sufficient. is there.

JP 2012-23335 A JP 2014-1388 A JP 2006-335958 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention improves the adhesion to a heat source and a heat radiating member, has excellent thermal conductivity, and further has excellent electrical insulation, a manufacturing method thereof, and a semiconductor device using the thermal conductive sheet. The purpose is to provide.

Means for solving the problems are as follows. That is,
<1> a thermally conductive filler-containing layer containing a binder resin and a thermally conductive filler;
A first adhesive layer containing a first adhesive;
An insulating resin layer containing an insulating resin and having insulating properties;
A second adhesive layer containing a second adhesive;
In this order,
The surface of the thermally conductive filler-containing layer is covered with an exuded component that has exuded from the thermally conductive filler-containing layer so as to follow the protruding shape of the protruding thermal conductive filler. It is a heat conductive sheet.
<2> The heat conductive sheet according to <1>, wherein the binder resin contains an addition reaction type silicone resin.
<3> The heat conductive sheet according to any one of <1> to <2>, wherein the heat conductive filler contains carbon fiber and an inorganic filler.
<4> Any one of <1> to <3>, wherein the total average thickness of the first adhesive layer, the insulating resin layer, and the second adhesive layer is 3 μm to 15 μm. It is a heat conductive sheet.
<5> The heat conductive sheet according to any one of <1> to <4>, wherein the insulating resin layer is a polyethylene terephthalate film.
<6> The thermal conductivity according to any one of <1> to <5>, wherein the volume resistivity at an applied voltage of 500 V, measured according to ASTM-D257, is 1.0 × 10 ¹⁰ Ω · cm or more. It is a sheet.
<7> The method for producing a heat conductive sheet according to any one of <1> to <6>,
Including a thermally conductive filler-containing layer production step of producing the thermally conductive filler-containing layer,
The said heat conductive filler content layer preparation process includes the process of the following (1)-(3), It is a manufacturing method of the heat conductive sheet characterized by the above-mentioned.
(1) A molded body preparation process for obtaining a molded body of the thermal conductive resin composition by molding and curing a thermal conductive resin composition containing a binder resin and a thermal conductive filler into a predetermined shape.
(2) A molded body sheet preparation process in which the molded body is cut into a sheet shape to obtain a molded body sheet on which the thermally conductive filler protrudes.
(3) A press that presses the molded body sheet and covers the surface of the molded body sheet with an exuding component that has exuded from the molded body sheet so as to follow the protruding shape of the protruding thermal conductive filler. processing.
<8> A heat source, a heat radiating member, and a heat conductive sheet sandwiched between the heat source and the heat radiating member,
The heat conductive sheet is the heat conductive sheet according to any one of <1> to <6>.

  According to the present invention, the conventional problems can be solved, the object can be achieved, the adhesion to the heat source and the heat radiating member is improved, the thermal conductivity is excellent, and the electrical insulation is also excellent. A sheet, a manufacturing method thereof, and a semiconductor device using the heat conductive sheet can be provided.

FIG. 1 is a schematic cross-sectional view of an example of a heat conductive sheet. FIG. 2 is a perspective view showing a state in which the molded body sheet is pressed through a spacer. FIG. 3 is a schematic cross-sectional view of an example of the semiconductor device of the present invention. FIG. 4 is a graph showing the relationship between the load and the thermal resistance value.

(Heat conduction sheet)
The heat conductive sheet of the present invention has at least a heat conductive filler-containing layer, a first pressure-sensitive adhesive layer, an insulating resin layer, and a second pressure-sensitive adhesive layer in this order. It has the member of.
The thermally conductive filler-containing layer contains a binder resin and a thermally conductive filler.
The first adhesive layer contains a first adhesive.
The insulating resin layer contains an insulating resin and has an insulating property.
The second adhesive layer contains a second adhesive.
The surface of the thermally conductive filler-containing layer is covered with an exuding component that has exuded from the thermally conductive filler-containing layer so as to follow the protruding shape of the protruding thermal conductive filler.

The present inventors diligently studied to develop a heat conductive sheet that improves adhesion to a heat source and a heat radiating member, is excellent in thermal conductivity, and is also excellent in electrical insulation.
In the heat conductive sheet, a method of coating the filler exposed on the sheet surface with the uncured component of the binder resin and the entire sheet surface was examined. However, it was not sufficient in terms of improving adhesion. Further, by covering the sheet surface with the uncured component of the binder resin, a certain level of electrical insulation was expected, but this was not sufficient to ensure electrical insulation.
On the other hand, the silicone resin frequently used in the heat conductive sheet is difficult to adhere to adherends such as other resins due to its characteristics, but even when the silicone resin is a binder resin, The present inventors have found that when combined with a tape having a pressure-sensitive adhesive on the surface, the pressure-sensitive adhesive force between the heat conductive sheet and the pressure-sensitive adhesive is not at least that which cannot be practically used.
As a result of further studies, the heat conductive sheet having the heat conductive filler-containing layer, the first adhesive layer, the insulating resin layer, and the second adhesive layer in this order, It has been found that the adhesion to the heat radiating member is improved, the thermal conductivity is excellent, and the electrical insulation is also excellent, and the present invention has been completed.

<Heat conductive filler-containing layer>
The thermally conductive filler-containing layer contains at least a binder resin and a thermally conductive filler, and further contains other components as necessary.

-Binder resin-
There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, a thermosetting polymer etc. are mentioned.

  Examples of the thermosetting polymer include crosslinked rubber, epoxy resin, polyimide resin, bismaleimide resin, benzocyclobutene resin, phenol resin, unsaturated polyester, diallyl phthalate resin, silicone resin, polyurethane, polyimide silicone, thermosetting type. Examples thereof include polyphenylene ether and thermosetting modified polyphenylene ether. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the crosslinked rubber include natural rubber, butadiene rubber, isoprene rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene propylene rubber, chlorinated polyethylene, chlorosulfonated polyethylene, butyl rubber, halogenated butyl rubber, fluorine rubber, Examples thereof include urethane rubber, acrylic rubber, polyisobutylene rubber, and silicone rubber. These may be used individually by 1 type and may use 2 or more types together.

  Among these, it is particularly preferable that the thermosetting polymer is a silicone resin from the viewpoints of excellent moldability and weather resistance, and adhesion and followability to electronic components.

  There is no restriction | limiting in particular as said silicone resin, Although it can select suitably according to the objective, It is preferable to contain the main ingredient of a liquid silicone gel, and a hardening | curing agent. Examples of such a silicone resin include an addition reaction type silicone resin, a heat vulcanization type millable type silicone resin using a peroxide for vulcanization, and the like. Among these, addition reaction type silicone resin is particularly preferable because adhesion between the heat generating surface of the electronic component and the heat sink surface is required.

  The addition reaction type silicone resin is preferably a two-component addition reaction type silicone resin containing a polyorganosiloxane having a vinyl group as a main ingredient and a polyorganosiloxane having a Si-H group as a curing agent.

  In the combination of the main component of the liquid silicone gel and the curing agent, the mixing ratio of the main component and the curing agent is not particularly limited and can be appropriately selected according to the purpose.

There is no restriction | limiting in particular as content of the said binder resin in the said heat conductive filler content layer, Although it can select suitably according to the objective, 10 mass%-50 mass% are preferable, 15 mass%-40 mass. % Is more preferable.
Moreover, there is no restriction | limiting in particular as content of the said binder resin in the said heat conductive filler content layer, Although it can select suitably according to the objective, 10 volume%-50 volume% are preferable, 15 volume%- 40% by volume is more preferable, and 30% by volume to 40% by volume is particularly preferable.

-Thermally conductive filler-
The thermally conductive filler is for efficiently conducting heat from a heat source to the heat radiating member.
As the heat conductive filler, carbon fiber and inorganic filler are preferable.

--- Carbon fiber--
There is no restriction | limiting in particular as said carbon fiber, According to the objective, it can select suitably, For example, what pitched, a PAN system, what graphitized PBO fiber, an arc discharge method, a laser evaporation method, CVD method (chemical) A compound synthesized by a vapor deposition method), a CCVD method (catalytic chemical vapor deposition method), or the like can be used. Among these, carbon fibers obtained by graphitizing PBO fibers and pitch-based carbon fibers are particularly preferable from the viewpoint of thermal conductivity.

  If necessary, the carbon fiber can be used by partially or entirely treating the carbon fiber. Examples of the surface treatment include oxidation treatment, nitriding treatment, nitration, sulfonation, or attaching a metal, a metal compound, an organic compound, or the like to the surface of a functional group or carbon fiber introduced to the surface by these treatments. The process etc. which are combined are mentioned. Examples of the functional group include a hydroxyl group, a carboxyl group, a carbonyl group, a nitro group, and an amino group.

  The average fiber length (average major axis length) of the carbon fiber is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 μm to 250 μm, more preferably 75 μm to 200 μm, and 90 μm to 170 μm. Is particularly preferred.

  There is no restriction | limiting in particular as an average fiber diameter (average short axis length) of the said carbon fiber, Although it can select suitably according to the objective, 4 micrometers-20 micrometers are preferable, and 5 micrometers-14 micrometers are more preferable.

The aspect ratio (average major axis length / average minor axis length) of the carbon fiber is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 8 or more, and more preferably 9-30. . When the aspect ratio is less than 8, since the fiber length (major axis length) of the carbon fiber is short, the thermal conductivity may be lowered.
Here, the average major axis length and the average minor axis length of the carbon fiber can be measured, for example, with a microscope, a scanning electron microscope (SEM), or the like.

  There is no restriction | limiting in particular as content of the said carbon fiber in the said heat conductive filler content layer, Although it can select suitably according to the objective, 10 volume%-40 volume% are preferable, 12 volume%-38 volume % Is more preferable, and 15% by volume to 35% by volume is particularly preferable. When the content is less than 10% by volume, it may be difficult to obtain a sufficiently low thermal resistance. When the content exceeds 40% by volume, the moldability of the thermally conductive filler-containing layer and the carbon fiber may be reduced. May affect the orientation of the film.

--Inorganic filler--
There is no restriction | limiting in particular about the shape, material, average particle diameter, etc. as said inorganic filler, According to the objective, it can select suitably. There is no restriction | limiting in particular as said shape, According to the objective, it can select suitably, For example, spherical shape, elliptical spherical shape, lump shape, granular form, flat shape, needle shape etc. are mentioned. Among these, spherical and elliptical shapes are preferable from the viewpoint of filling properties, and spherical shapes are particularly preferable.
In the present specification, the inorganic filler is different from the carbon fiber.

  Examples of the inorganic filler include aluminum nitride (aluminum nitride: AlN), silica, alumina (aluminum oxide), boron nitride, titania, glass, zinc oxide, silicon carbide, silicon (silicon), silicon oxide, aluminum oxide, and metal. And particles. These may be used individually by 1 type and may use 2 or more types together. Among these, alumina, boron nitride, aluminum nitride, zinc oxide, and silica are preferable, and alumina and aluminum nitride are particularly preferable from the viewpoint of thermal conductivity.

  The inorganic filler may be subjected to a surface treatment. When the inorganic filler is treated with a coupling agent as the surface treatment, the dispersibility of the inorganic filler is improved and the flexibility of the heat conductive sheet is improved.

There is no restriction | limiting in particular as an average particle diameter of the said inorganic filler, According to the objective, it can select suitably.
When the inorganic filler is alumina, the average particle size is preferably 1 μm to 10 μm, more preferably 1 μm to 5 μm, and particularly preferably 4 μm to 5 μm. When the average particle size is less than 1 μm, the viscosity increases and mixing may become difficult. When the average particle size exceeds 10 μm, the thermal resistance of the heat conductive sheet may increase.
When the inorganic filler is aluminum nitride, the average particle size is preferably 0.3 μm to 6.0 μm, more preferably 0.3 μm to 2.0 μm, and particularly preferably 0.5 μm to 1.5 μm. If the average particle size is less than 0.3 μm, the viscosity may increase and mixing may be difficult, and if it exceeds 6.0 μm, the thermal resistance of the heat conductive sheet may increase.
The average particle diameter of the inorganic filler can be measured by, for example, a particle size distribution meter or a scanning electron microscope (SEM).

  There is no restriction | limiting in particular as content of the said inorganic filler in the said heat conductive filler content layer, Although it can select suitably according to the objective, 25 volume%-65 volume% are preferable, 30 volume%-60 volume % Is more preferable. When the content is less than 25% by volume, the heat resistance of the heat conductive sheet may increase, and when it exceeds 60% by volume, the flexibility of the heat transfer sheet may decrease.

-Other ingredients-
The other component in the thermally conductive filler-containing layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a thixotropic agent, a dispersant, a curing accelerator, a retarder, a slight adhesion Examples include an imparting agent, a plasticizer, a flame retardant, an antioxidant, a stabilizer, and a colorant.

  In order to obtain a heat conductive sheet having a high heat conductivity, a spherical inorganic substance is used to maintain the shape, not simply increasing the content of carbon fiber having a high heat conductivity in the heat conductive filler-containing layer. Filler must be added. Moreover, in order to lower the viscosity of the heat conductive resin composition at the time of extrusion described later, the blending of the carbon fiber and the spherical inorganic filler must be made to an appropriate amount.

  There is no restriction | limiting in particular as average thickness of the said heat conductive filler content layer, Although it can select suitably according to the objective, 0.05 mm-5.00 mm are preferable, 0.07 mm-3.00 mm are more preferable. 0.10 mm to 2.00 mm is particularly preferable.

The surface of the thermally conductive filler-containing layer is covered with an exuding component that has exuded from the thermally conductive filler-containing layer so as to follow the protruding shape of the protruding thermal conductive filler.
The method of making the surface of the heat conductive filler-containing layer in this way can be performed, for example, by a press process described later.

<First adhesive layer, insulating resin layer, second adhesive layer>
The first adhesive layer contains a first adhesive.
The insulating resin layer contains an insulating resin and has an insulating property.
The second adhesive layer contains a second adhesive.

There is no restriction | limiting in particular as said 1st adhesive, According to the objective, it can select suitably, For example, a silicone adhesive, an acrylic adhesive, a rubber adhesive, etc. are mentioned. Among these, acrylic pressure-sensitive adhesives are preferable from the viewpoint of durability, availability, and adhesive strength.
There is no restriction | limiting in particular as said 2nd adhesive, According to the objective, it can select suitably, For example, a silicone type adhesive, an acrylic adhesive, a rubber-type adhesive etc. are mentioned. Among these, acrylic pressure-sensitive adhesives are preferable from the viewpoint of durability, availability, and adhesive strength.

There is no restriction | limiting in particular as said insulating resin, According to the objective, it can select suitably, For example, polyester (for example, polyethylene terephthalate), a polypropylene, etc. are mentioned.
There is no restriction | limiting in particular as a structure of the said insulating resin layer, According to the objective, it can select suitably, For example, a film, a nonwoven fabric, etc. are mentioned.
Examples of the nonwoven fabric include melt blown nonwoven fabric, card nonwoven fabric, spunbond nonwoven fabric, and spunlace nonwoven fabric. These nonwoven fabrics are made of, for example, polyester or polypropylene.
Among these, the insulating resin layer is preferably a polyethylene terephthalate film because the insulating resin layer can be reduced in thickness, excellent in electrical insulation, and excellent in adhesiveness with a pressure-sensitive adhesive.

There is no restriction | limiting in particular as average thickness of the said insulating resin layer, Although it can select suitably according to the objective, 1 micrometer-6 micrometers are preferable. If the average thickness is less than 1 μm, the strength may be insufficient.
There is no restriction | limiting in particular as average thickness of a said 1st adhesion layer, According to the objective, it can select suitably, For example, 0.5 micrometer-2 micrometers etc. are mentioned.
There is no restriction | limiting in particular as average thickness of a said 2nd adhesion layer, According to the objective, it can select suitably, For example, 0.5 micrometer-2 micrometers etc. are mentioned.
The total average thickness of the first adhesive layer, the insulating resin layer, and the second adhesive layer is preferably 3 μm to 15 μm, and more preferably 5 μm to 10 μm. When the total average thickness is less than 3 μm, it may be difficult to produce the heat conductive sheet. When the total average thickness exceeds 15 μm, the thermal resistance of the heat conductive sheet may increase.
The ratio of the average thickness of the insulating resin layer to the total average thickness of the first adhesive layer, the insulating resin layer, and the second adhesive layer is preferably 10% to 60%, preferably 20% to 60% is more preferable. When the ratio exceeds 60%, the thickness of the first adhesive layer and the second adhesive layer may be insufficient, and the adhesive force may be lowered.

The thermal conductive sheet preferably has a volume resistivity of 1.0 × 10 ¹⁰ Ω · cm or more at an applied voltage of 500 V, measured according to ASTM-D257.
There is no restriction | limiting in particular as an upper limit of the said volume resistivity, According to the objective, it can select suitably, For example, the said volume resistivity is 1.0 * 10 < ¹⁸ > ohm * cm or less.

  Here, an example of the heat conductive sheet will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an example of the heat conductive sheet. The heat conductive sheet 1 of FIG. 1 has the heat conductive filler containing layer 12, the 1st adhesion layer 13, the insulating resin layer 14, and the 2nd adhesion layer 15 in this order.

(Method for producing heat conductive sheet)
The manufacturing method of the heat conductive sheet of this invention contains the heat conductive filler content layer preparation process at least, and also includes other processes, such as a double-sided adhesive sheet lamination process, as needed.
The said heat conductive sheet of this invention can be suitably manufactured with the manufacturing method of the said heat conductive sheet of this invention.

<Thermal conductive filler-containing layer production process>
The heat conductive filler-containing layer preparation step is a step of preparing the heat conductive filler-containing layer, and includes the following processes (1) to (3).
(1) Molded body manufacturing process (2) Molded sheet manufacturing process (3) Press process

<< Molded body preparation process >>
As the molded body production process, a process for obtaining a molded body of the thermally conductive resin composition by molding and curing a thermally conductive resin composition containing a binder resin and a thermally conductive filler into a predetermined shape. If it is, there will be no restriction | limiting in particular, According to the objective, it can select suitably.

-Thermally conductive resin composition-
The said heat conductive resin composition contains binder resin and a heat conductive filler at least, and also contains another component as needed.
The said heat conductive resin composition can be prepared with a well-known method.

  In the molding production process, the method for molding the thermally conductive resin composition into a predetermined shape is not particularly limited and can be appropriately selected according to the purpose. For example, extrusion molding, mold molding Law.

The heat conductive filler obtained is obtained by filling the heat conductive resin composition in a hollow mold and heat-curing the heat conductive resin composition. It is preferable at the point which can orient the said heat conductive filler (for example, carbon fiber) in a content layer at random.
In the obtained thermally conductive filler-containing layer, since the carbon fibers are randomly oriented, the entanglement between the carbon fibers increases, so that the carbon fibers are oriented in a certain direction. However, the thermal conductivity is increased. Moreover, in the case where the thermally conductive filler contains the carbon fiber and the spherical inorganic filler, in addition to the entanglement of the carbon fibers, the carbon fibers are randomly oriented, Since the number of contact points between the carbon fiber and the spherical inorganic filler also increases, the thermal conductivity is further increased as compared with the case where the carbon fiber is oriented in a certain direction.

  The extrusion molding method and the mold molding method are not particularly limited, and the viscosity of the heat conductive resin composition and the obtained heat conduction can be selected from various known extrusion molding methods and mold molding methods. It can employ | adopt suitably according to the characteristic etc. which are requested | required of a conductive filler content layer.

  When extruding the thermally conductive resin composition from a die in the extrusion molding method, or when pressing the thermally conductive resin composition into a mold in the mold molding method, for example, the binder resin flows. Some carbon fibers are oriented along the flow direction, but many are randomly oriented.

  In addition, when a slit is attached to the tip of the die, the carbon fiber tends to be easily oriented at the center with respect to the width direction of the extruded molded body block. On the other hand, the carbon fiber tends to be randomly oriented in the peripheral portion with respect to the width direction of the molded body block due to the influence of the slit wall.

  The size and shape of the molded body (block-shaped molded body) can be determined according to the required size of the thermally conductive filler-containing layer. For example, a rectangular parallelepiped having a vertical size of 0.5 cm to 15 cm and a horizontal size of 0.5 cm to 15 cm can be given. The length of the rectangular parallelepiped may be determined as necessary.

  It is preferable that hardening of the said heat conductive resin composition in the said molded object preparation process is thermosetting. There is no restriction | limiting in particular as the curing temperature in the said thermosetting, It can select suitably according to the objective, For example, when the said binder resin contains the main ingredient of a liquid silicone gel, and a hardening | curing agent, 80 degreeC ~ 120 ° C. is preferred. There is no restriction | limiting in particular as hardening time in the said thermosetting, According to the objective, it can select suitably, For example, 1 hour-10 hours etc. are mentioned.

-Molded sheet manufacturing process-
The molded body sheet preparation process is not particularly limited as long as it is a process for cutting the molded body into a sheet shape and obtaining a molded body sheet with the thermally conductive filler protruding on the surface. For example, it can be performed by a slicing apparatus.

  In the molded body sheet manufacturing process, the molded body is cut into a sheet shape to obtain a molded body sheet. The thermally conductive filler protrudes from the surface of the obtained molded body sheet. This is because when the molded body is cut into a sheet shape by a slicing device or the like, the cured component of the binder resin is cut by a slicing device or the like due to a difference in hardness between the cured component of the binder resin and the thermally conductive filler. This is considered to be because the cured component of the binder resin is removed from the surface of the thermally conductive filler on the surface of the molded body sheet.

  There is no restriction | limiting in particular as said slicing apparatus, According to the objective, it can select suitably, For example, an ultrasonic cutter, a planer (鉋), etc. are mentioned. As the cutting direction of the molded body, when the molding method is an extrusion molding method, 60 ° to 120 ° with respect to the extrusion direction is preferable because some are oriented in the extrusion direction, and 70 ° to 100 ° The degree is more preferable, and 90 degrees (vertical) is particularly preferable.

  The average thickness of the molded sheet is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 0.06 mm to 5.01 mm is preferable, 0.08 mm to 3.01 mm is more preferable, and 0 .11 mm to 2.01 mm is particularly preferable.

-Press processing-
As the pressing treatment, the molded body sheet is pressed, and the surface of the molded body sheet is subjected to an exuding component that has oozed out of the molded body sheet so as to follow the convex shape of the protruding thermal conductive filler. If it is the process which covers, there will be no restriction | limiting in particular, According to the objective, it can select suitably.
Here, the “exudation component” is a component that is included in the thermally conductive resin composition but does not contribute to curing, such as a non-curable component and a component that is not cured among the binder resin. Means.

  The said press can be performed using a pair of press apparatus which consists of a flat board and a press head with the flat surface, for example. Moreover, you may carry out using a pinch roll.

  The pressure at the time of pressing is not particularly limited and can be appropriately selected according to the purpose. However, if it is too low, the thermal resistance tends to be the same as when not pressing, and if it is too high, the sheet is stretched. Since there exists a tendency, 0.1 MPa-100 MPa are preferable, and 0.5 MPa-95 MPa are more preferable.

  There is no restriction | limiting in particular as time of the said press, According to the component of binder resin, a press pressure, a sheet area, the amount of exudation of an exuding component, etc., it can select suitably.

  The press treatment may be performed while heating using a press head with a built-in heater in order to further promote the effects of exudation of the exuding component and covering the surface of the molded body sheet. In order to enhance such an effect, the heating temperature is preferably higher than the glass transition temperature of the binder resin. Thereby, press time can be shortened.

In the pressing treatment, the extruding component is exuded from the molding sheet by pressing the molding sheet, and the surface is covered with the exuding component. Therefore, the obtained thermally conductive filler-containing layer can improve followability and adhesion to the surface of the heat source and the heat radiating member, and can reduce thermal resistance. Moreover, the increase in thermal resistance can be avoided because the coating with the exuding component has a thickness that reflects the shape of the thermally conductive filler on the sheet surface.
Moreover, the heat conductive filler content layer obtained improves the adhesiveness with the first pressure-sensitive adhesive layer and improves the adhesion with the first pressure-sensitive adhesive layer due to the exuding component.

  In addition, a heat conductive filler content layer is compressed to the thickness direction by pressing, and can increase the frequency of contact between heat conductive fillers. Thereby, it becomes possible to reduce the thermal resistance of a heat conductive sheet.

  The press treatment is preferably performed using a spacer for compressing the molded sheet to a predetermined thickness. That is, as shown in FIG. 2, the thermally conductive filler-containing layer is arranged according to the height of the spacer 10 by placing the spacer 10 on the mounting surface facing the press head and pressing the molded sheet 11. Further, it can be formed to a predetermined sheet thickness.

<Double-sided PSA sheet lamination process>
As the double-sided pressure-sensitive adhesive sheet laminating step, the double-sided pressure-sensitive adhesive sheet formed by laminating the first pressure-sensitive adhesive layer, the insulating resin layer, and the second pressure-sensitive adhesive layer in this order contains the thermally conductive filler. If it is a process of laminating the first adhesive layer on the layer so as to be in contact with the thermally conductive filler-containing layer, there is no particular limitation and it can be appropriately selected according to the purpose.

There is no restriction | limiting in particular as a manufacturing method of the said double-sided adhesive sheet, According to the objective, it can select suitably, For example, the method of apply | coating an adhesive composition to both surfaces of the said insulating resin layer, etc. are mentioned.
The pressure-sensitive adhesive composition contains, for example, an acrylic polymer called a base polymer, a crosslinking agent (for example, a polyfunctional acrylate compound, an isocyanate compound, etc.), a tackifier (for example, rosin), a polymerization initiator, a solvent, and the like.
Examples of the coating method include a screen printing method, a doctor blade method, and a comma coater method.
When the pressure-sensitive adhesive composition contains a solvent and an isocyanate compound, the base polymer and the isocyanate compound react with each other while the solvent evaporates by heating as necessary after the coating, whereby a pressure-sensitive adhesive layer is obtained. .
Alternatively, when the pressure-sensitive adhesive composition contains a polyfunctional acrylate compound and a polymerization initiator and is a solvent-free pressure-sensitive adhesive composition, after application, the base polymer is irradiated with active energy rays. And a polyfunctional acrylate compound react to obtain an adhesive layer.

(Semiconductor device)
The semiconductor device of the present invention includes at least a heat source, a heat radiating member, and a heat conductive sheet, and further includes other members as necessary.
The heat conductive sheet is sandwiched between the heat source and the heat radiating member.
In the semiconductor device, the heat source is in contact with the second adhesive layer of the heat conductive sheet, and the heat dissipation member is in contact with the heat conductive filler-containing layer of the heat conductive sheet. It is preferable in terms of thermal conductivity.

<Heat source>
There is no restriction | limiting in particular as said heat source, According to the objective, it can select suitably, For example, an electronic component etc. are mentioned. Examples of the electronic component include a CPU, MPU, graphic arithmetic element, and the like.

<Heat dissipation member>
The heat radiating member is not particularly limited as long as the heat generated from the heat source is conducted and dissipated to the outside, and can be appropriately selected according to the purpose. For example, a heat radiating device, a cooler, a heat sink , Heat spreader, die pad, printed circuit board, cooling fan, Peltier element, heat pipe, housing, and the like.

<Heat conduction sheet>
The heat conductive sheet is the heat conductive sheet of the present invention.

  An example of the semiconductor device of the present invention will be described with reference to the drawings.

FIG. 3 is a schematic cross-sectional view showing an example of the semiconductor device of the present invention.
The semiconductor device includes a heat conductive sheet 1, a heat spreader 2, an electronic component 3, a heat sink 5, and a wiring substrate 6.

The heat conductive sheet 1 radiates heat generated by the electronic component 3, and is fixed to the main surface 2 a facing the electronic component 3 of the heat spreader 2, as shown in FIG. 3, and the electronic component 3, the heat spreader 2, It is sandwiched between the two. Further, the heat conductive sheet 1 is sandwiched between the heat spreader 2 and the heat sink 5. The heat conductive sheet 1 radiates heat of the electronic component 3 together with the heat spreader 2.
In the semiconductor device of FIG. 3, the second adhesive layer of the heat conductive sheet 1 is in contact with the electronic component 3, and the heat conductive filler-containing layer of the heat conductive sheet 1 is in contact with the heat spreader 2.
The heat conductive filler-containing layer of the heat conductive sheet 1 has an exuding component that exudes from the heat conductive filler-containing layer, and the surface is covered with the exuding component.

  The heat spreader 2 is formed in, for example, a rectangular plate shape, and includes a main surface 2a facing the electronic component 3 and a side wall 2b erected along the outer periphery of the main surface 2a. In the heat spreader 2, a heat conductive sheet 1 is provided on a main surface 2a surrounded by a side wall 2b, and a heat sink 5 is provided on the other surface 2c opposite to the main surface 2a via the heat conductive sheet 1. The heat spreader 2 has a higher thermal conductivity, so that the thermal resistance is reduced and the heat of the electronic component 3 such as a semiconductor element is efficiently absorbed. Therefore, the heat spreader 2 is formed using, for example, copper or aluminum having good thermal conductivity. be able to.

  The electronic component 3 is a semiconductor package such as a BGA, for example, and is mounted on the wiring board 6. Further, the heat spreader 2 also has the front end surface of the side wall 2b mounted on the wiring board 6, and thereby surrounds the electronic component 3 at a predetermined distance by the side wall 2b.

  The heat conductive sheet 1 is adhered to the main surface 2 a of the heat spreader 2, thereby absorbing heat generated by the electronic component 3 and dissipating it from the heat sink 5. The adhesion between the electronic component 3 and the heat conductive sheet 1 is performed by the adhesive force of the second adhesive layer of the heat conductive sheet 1, and the adhesion between the heat spreader 2 and the heat conductive sheet 1 is the heat conduction of the heat conductive sheet 1. This is performed by the adhesive strength of the conductive filler-containing layer.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
Two-component addition reaction type liquid silicone resin, 20 vol% of alumina particles (thermal conductive particles: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 4 μm, which is coupled with a silane coupling agent, and an average fiber length of 150 μm, 22 vol% of pitch-based carbon fibers with an average fiber diameter of 9 μm (thermal conductive fiber: manufactured by Nippon Graphite Fiber Co., Ltd.) and aluminum nitride with an average particle diameter of 1 μm coupled with a silane coupling agent (thermal conductive particles: Co., Ltd.) A silicone resin composition (thermally conductive resin composition) was prepared by dispersing 24 vol% of Tokuyama).
The two-component addition-reaction type liquid silicone resin is silicone A liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (A)), 30% by mass, silicone B liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (B)). It is a mixture at a ratio of 70% by mass.
The obtained silicone resin composition was extruded into a rectangular parallelepiped mold (50 mm × 50 mm) with a PET film peel-treated on the inner wall to mold a silicone molded body.
The obtained silicone molding was cured in an oven at 100 ° C. for 6 hours to obtain a silicone cured product.
The obtained silicone cured product was heated in an oven at 100 ° C. for 1 hour and then cut to obtain a molded sheet having an average thickness of 0.11 mm.
After sandwiching the obtained molded sheet between the peeled PET films (2 sheets) and pressing without inserting a spacer, a thermally conductive filler-containing layer (sheet) sample having an average thickness of 0.10 mm is obtained. Obtained. The pressing conditions were 3 min at 50 ° C. and 0.5 MPa setting.
The filler that appears on the surface immediately after slicing (cutting) is not covered with the binder component, but the binder is pressed against the sheet by the press, and the binder component comes out on the surface when the filler is immersed in the sheet. Therefore, the sheet surface is covered with the binder component while reflecting the filler shape.
A binder component can be confirmed on the peeled PET surface that was in contact with the sheet after pressing.

The release liner was peeled from one side of the double-sided tape, and the double-sided tape was laminated so that the surface from which the release liner was peeled was in contact with the surface of the thermally conductive filler-containing layer from which oil exuded by pressing. A heat conductive sheet was obtained by passing the laminate through a press roll.
Although it was expected that a double-sided tape (average thickness of 5 μm) having an acrylic adhesive layer on both sides was laminated on the silicone-based heat conductive sheet, it was not expected to adhere at all, but a laminate could be obtained contrary to expectations.
The release liner on the other side was peeled off, and the thermal characteristics and volume resistance of the heat conductive sheet were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.

The double-sided tape was obtained as follows.
A double-sided tape in which an adhesive layer was formed on both surfaces of a polyethylene terephthalate film having an average thickness of 2.5 μm so that the average thickness on one side after coating was 1.25 μm was prepared. The adhesive layer comprises 94 parts by mass of a partial polymer of acrylic acid and 2-ethylhexyl acrylate, 6 parts by mass of tetrahydrofurfuryl acrylate, 1.0 part by mass of a photo radical initiator (Lucirin TPO, manufactured by BASF SE), and an adhesive. It is an acrylic pressure-sensitive adhesive layer obtained by curing a pressure-sensitive adhesive composition comprising 15 parts by mass of KE-604 (rosin ester, manufactured by Arakawa Chemical Industries, Ltd.) as an imparting agent by ultraviolet irradiation. The adhesive layer has a release liner.
The measurement of thermal characteristics was performed using a thermal resistance measuring device (Dexerials Co., Ltd.) based on ASTM-D5470. The same applies to the following examples and comparative examples.
The volume resistance was measured using Hiresta MCP-HT800 (Mitsubishi Chemical Analytech Co., Ltd.). The same applies to the following examples and comparative examples.

(Example 2)
Two-component addition reaction type liquid silicone resin, 20 vol% of alumina particles (thermal conductive particles: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 4 μm, which is coupled with a silane coupling agent, and an average fiber length of 150 μm, 22 vol% of pitch-based carbon fibers with an average fiber diameter of 9 μm (thermal conductive fiber: manufactured by Nippon Graphite Fiber Co., Ltd.) and aluminum nitride with an average particle diameter of 1 μm coupled with a silane coupling agent (thermal conductive particles: Co., Ltd.) A silicone resin composition (thermally conductive resin composition) was prepared by dispersing 24 vol% of Tokuyama).
Two-component addition-reaction type liquid silicone resin is 50% by mass of silicone A liquid [Toray Dow Corning 527 (A)], silicone B liquid [Toray Dow Corning 527 (B)]. It is a mixture of 50% by mass.
The obtained silicone resin composition was extruded into a rectangular parallelepiped mold (50 mm × 50 mm) with a PET film peel-treated on the inner wall to mold a silicone molded body.
The obtained silicone molding was cured in an oven at 100 ° C. for 6 hours to obtain a silicone cured product.
The obtained silicone cured product was heated in an oven at 100 ° C. for 1 hour and then cut to obtain a molded sheet having an average thickness of 0.31 mm.
After sandwiching the obtained molded sheet between two peeled PET films, a spacer having a thickness of 0.30 mm was inserted and pressed, whereby a thermally conductive filler-containing layer having an average thickness of 0.30 mm ( Sheet) A sample was obtained. The pressing conditions were 3 min at 50 ° C. and 0.5 MPa setting.
The filler that appears on the surface immediately after slicing (cutting) is not covered with the binder component, but the binder is pressed against the sheet by the press, and the binder component comes out on the surface when the filler is immersed in the sheet. Therefore, the sheet surface is covered with the binder component while reflecting the filler shape.
A binder component can be confirmed on the peeled PET surface that was in contact with the sheet after pressing.

The release liner was peeled from one side of the double-sided tape, and the double-sided tape was laminated so that the surface from which the release liner was peeled was in contact with the surface of the thermally conductive filler-containing layer from which oil exuded by pressing. A heat conductive sheet was obtained by passing the laminate through a press roll.
Although it was expected that a double-sided tape (average thickness of 5 μm) having an acrylic adhesive layer on both sides was laminated on the silicone-based heat conductive sheet, it was not expected to adhere at all, but a laminate could be obtained contrary to expectations.
The release liner on the other side was peeled off, and the thermal characteristics and volume resistance of the heat conductive sheet were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.
The double-sided tape used in Example 1 was used as the double-sided tape.

(Example 3)
Two-component addition reaction type liquid silicone resin, 20 vol% of alumina particles (thermal conductive particles: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 4 μm, which is coupled with a silane coupling agent, and an average fiber length of 150 μm, 22 vol% of pitch-based carbon fibers with an average fiber diameter of 9 μm (thermal conductive fiber: manufactured by Nippon Graphite Fiber Co., Ltd.) and aluminum nitride with an average particle diameter of 1 μm coupled with a silane coupling agent (thermal conductive particles: Co., Ltd.) A silicone resin composition (thermally conductive resin composition) was prepared by dispersing 24 vol% of Tokuyama).
The two-component addition-reaction type liquid silicone resin is silicone A liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (A)), 60% by mass, silicone B liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (B)). It is a mixture of 40% by mass.
The obtained silicone resin composition was extruded into a rectangular parallelepiped mold (50 mm × 50 mm) with a PET film peel-treated on the inner wall to mold a silicone molded body.
The obtained silicone molding was cured in an oven at 100 ° C. for 6 hours to obtain a silicone cured product.
The obtained cured silicone was heated in an oven at 100 ° C. for 1 hour and then cut to obtain a molded body sheet having an average thickness of 0.51 mm.
The obtained molded sheet was sandwiched between two peeled PET films, and then inserted with a 0.50 mm spacer and pressed to obtain a thermally conductive filler-containing layer having an average thickness of 0.50 mm (sheet) ) A sample was obtained. The pressing conditions were 3 min at 50 ° C. and 0.5 MPa setting.
The filler that appears on the surface immediately after slicing (cutting) is not covered with the binder component, but the binder is pressed against the sheet by the press, and the binder component comes out on the surface when the filler is immersed in the sheet. Therefore, the sheet surface is covered with the binder component while reflecting the filler shape.
A binder component can be confirmed on the peeled PET surface that was in contact with the sheet after pressing.

The release liner was peeled from one side of the double-sided tape, and the double-sided tape was laminated so that the surface from which the release liner was peeled was in contact with the surface of the thermally conductive filler-containing layer from which oil exuded by pressing. A heat conductive sheet was obtained by passing the laminate through a press roll.
Although it was expected that a double-sided tape (average thickness of 5 μm) having an acrylic adhesive layer on both sides was laminated on the silicone-based heat conductive sheet, it was not expected to adhere at all, but a laminate could be obtained contrary to expectations.
The release liner on the other side was peeled off, and the thermal characteristics and volume resistance of the heat conductive sheet were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.
The double-sided tape used in Example 1 was used as the double-sided tape.

Example 4
Two-component addition reaction type liquid silicone resin, 20 vol% of alumina particles (thermal conductive particles: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 4 μm, which is coupled with a silane coupling agent, and an average fiber length of 150 μm, 22 vol% of pitch-based carbon fibers with an average fiber diameter of 9 μm (thermal conductive fiber: manufactured by Nippon Graphite Fiber Co., Ltd.) and aluminum nitride with an average particle diameter of 1 μm coupled with a silane coupling agent (thermal conductive particles: Co., Ltd.) A silicone resin composition (thermally conductive resin composition) was prepared by dispersing 24 vol% of Tokuyama).
The two-component addition-reaction type liquid silicone resin is silicone A liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (A)), 60% by mass, silicone B liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (B)). It is a mixture of 40% by mass.
The obtained silicone resin composition was extruded into a rectangular parallelepiped mold (50 mm × 50 mm) with a PET film peel-treated on the inner wall to mold a silicone molded body.
The obtained silicone molding was cured in an oven at 100 ° C. for 6 hours to obtain a silicone cured product.
The obtained silicone cured product was heated in an oven at 100 ° C. for 1 hour and then cut to obtain a molded sheet having an average thickness of 2.01 mm.
After sandwiching the obtained molded body sheet between two peeled PET films, a spacer having a thickness of 2.00 mm is inserted and pressed, whereby a thermally conductive filler-containing layer having an average thickness of 2.00 mm ( Sheet) A sample was obtained. The pressing conditions were 3 min at 50 ° C. and 0.5 MPa setting.
The filler that appears on the surface immediately after slicing (cutting) is not covered with the binder component, but the binder is pressed against the sheet by the press, and the binder component comes out on the surface when the filler is immersed in the sheet. Therefore, the sheet surface is covered with the binder component while reflecting the filler shape.
A binder component can be confirmed on the peeled PET surface that was in contact with the sheet after pressing.

The release liner was peeled from one side of the double-sided tape, and the double-sided tape was laminated so that the surface from which the release liner was peeled was in contact with the surface of the thermally conductive filler-containing layer from which oil exuded by pressing. A heat conductive sheet was obtained by passing the laminate through a press roll.
Although it was expected that a double-sided tape (average thickness of 5 μm) having an acrylic adhesive layer on both sides was laminated on the silicone-based heat conductive sheet, it was not expected to adhere at all, but a laminate could be obtained contrary to expectations.
The release liner on the other side was peeled off, and the thermal characteristics and volume resistance of the heat conductive sheet were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.
The double-sided tape used in Example 1 was used as the double-sided tape.

(Example 5)
Two-component addition reaction type liquid silicone resin, 20 vol% of alumina particles (thermal conductive particles: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 4 μm, which is coupled with a silane coupling agent, and an average fiber length of 150 μm, 22 vol% of pitch-based carbon fibers with an average fiber diameter of 9 μm (thermal conductive fiber: manufactured by Nippon Graphite Fiber Co., Ltd.) and aluminum nitride with an average particle diameter of 1 μm coupled with a silane coupling agent (thermal conductive particles: Co., Ltd.) A silicone resin composition (thermally conductive resin composition) was prepared by dispersing 24 vol% of Tokuyama).
The two-component addition-reaction type liquid silicone resin is silicone A liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (A)), 60% by mass, silicone B liquid (manufactured by Toray Dow Corning Co., Ltd., 527 (B)). It is a mixture of 40% by mass.
The obtained silicone resin composition was extruded into a rectangular parallelepiped mold (50 mm × 50 mm) with a PET film peel-treated on the inner wall to mold a silicone molded body.
The obtained silicone molding was cured in an oven at 100 ° C. for 6 hours to obtain a silicone cured product.
The obtained silicone cured product was heated in an oven at 100 ° C. for 1 hour and then cut to obtain a molded sheet having an average thickness of 2.01 mm.
The obtained molded sheet was sandwiched between two peeled PET films, and then inserted with a 2.0 mm spacer and pressed to obtain a thermally conductive filler-containing layer (sheet) having an average thickness of 2.00 mm ) A sample was obtained. The pressing conditions were 3 min at 50 ° C. and 0.5 MPa setting.
The filler that appears on the surface immediately after slicing (cutting) is not covered with the binder component, but the binder is pressed against the sheet by the press, and the binder component comes out on the surface when the filler is immersed in the sheet. Therefore, the sheet surface is covered with the binder component while reflecting the filler shape.
A binder component can be confirmed on the peeled PET surface that was in contact with the sheet after pressing.

The release liner was peeled from one side of the double-sided tape, and the double-sided tape was laminated so that the surface from which the release liner was peeled was in contact with the surface of the thermally conductive filler-containing layer from which oil exuded by pressing. A heat conductive sheet was obtained by passing the laminate through a press roll.
Although it was expected that a double-sided tape (average thickness 10 μm) having an acrylic adhesive layer on both sides was laminated on a silicone-based heat conductive sheet, it was not expected to be attached at all, but a laminate could be obtained contrary to expectations.
The release liner on the other side was peeled off, and the thermal characteristics and volume resistance of the heat conductive sheet were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.
For the double-sided tape, double-sided tape (average thickness 10 μm) having the same pressure-sensitive adhesive composition as Example 1 except that the average thickness of the single-sided adhesive layer was changed to 3.75 μm in the double-sided tape of Example 1. Using.

(Comparative Example 1)
<Preparation of insulating coated carbon fiber>
A pitch-based carbon fiber (thermal conductive fiber: manufactured by Nippon Graphite Fiber Co., Ltd.) having an average fiber length of 150 μm and an average fiber diameter of 9 μm was insulated with silica by a sol-gel method to obtain an insulation-coated carbon fiber. The thickness of silica (insulating film) on the surface of the carbon fiber was 77 nm.

<Preparation of heat conductive sheet>
20 vol% of alumina particles (thermal conductive particles: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 4 μm obtained by coupling with a silane coupling agent to a two-component addition reaction type liquid silicone resin, and the insulation-coated carbon fiber. A silicone resin composition (thermal conductive resin composition) was dispersed by dispersing 22 vol% and 24 vol% of aluminum nitride (thermal conductive particles: manufactured by Tokuyama Co., Ltd.) having an average particle diameter of 1 μm coupled with a silane coupling agent. ) Was prepared.
The two-component addition-reaction type liquid silicone resin is silicone A liquid (Toray Dow Corning Co., Ltd., 527 (A)) 55% by mass, silicone B liquid (Toray Dow Corning Co., Ltd., 527 (B)). It is a mixture of 45% by mass.
The obtained silicone resin composition was extruded into a rectangular parallelepiped mold (50 mm × 50 mm) with a PET film peel-treated on the inner wall to mold a silicone molded body.
The obtained silicone molding was cured in an oven at 100 ° C. for 6 hours to obtain a silicone cured product.
The obtained cured silicone was heated in an oven at 100 ° C. for 1 hour and then cut to obtain a molded body sheet having an average thickness of 0.51 mm.
The obtained molded sheet was sandwiched between two peeled PET films and then pressed without a spacer to obtain a heat conductive sheet sample having an average thickness of 0.50 mm. The pressing conditions were 3 min at 50 ° C. and 0.5 MPa setting.
The filler that appears on the surface immediately after slicing (cutting) is not covered with the binder component, but the binder is pressed against the sheet by the press, and the binder component comes out on the surface when the filler is immersed in the sheet. Therefore, the sheet surface is covered with the binder component while reflecting the filler shape.
A binder component can be confirmed on the peeled PET surface that was in contact with the sheet after pressing.

  The thermal characteristics and volume resistance of the obtained heat conductive sheet were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.

(Comparative Example 2)
The thermal conductive filler-containing layer produced in Example 4 was used as a thermal conductive sheet, and thermal characteristics and volume resistance were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.

(Comparative Example 3)
The molded body sheet (average thickness 0.11 mm) produced in Example 1 before pressing was used.
The release liner was peeled off from one surface of the double-sided tape, the double-sided tape was laminated on the surface of the molded product sheet so that the surface from which the release liner was peeled was in contact, and the resulting laminate was passed through a pressure roll. Then, when trying to peel the other release liner of the double-sided tape, the molded body sheet and the double-sided tape were peeled off.
The double-sided tape used in Example 1 was used as the double-sided tape.

(Comparative Example 4)
The heat conductive filler-containing layer (sheet) having an average thickness of 0.50 mm obtained in Example 3 was used.
Using the pressure-sensitive adhesive composition for producing the double-sided tape in Example 1, an acrylic pressure-sensitive adhesive layer having an average thickness of 5 μm was produced on a release-treated PET (polyethylene terephthalate) film to obtain a pressure-sensitive adhesive tape. It was.
The pressure-sensitive adhesive tape was laminated on the surface of the thermally conductive filler-containing layer from which oil had oozed out by pressing so that the pressure-sensitive adhesive layer was in contact, and the obtained laminate was passed through a pressure roll to obtain a heat conductive sheet.
The release-treated PET was peeled off, and the thermal characteristics and volume resistance of the heat conductive sheet were evaluated. The thermal characteristics were measured by a method based on ASTM-D5470, and the volume resistance was measured by a method based on ASTM-D257.

[Drop test]
The composite heat conductive sheets according to Examples 1 to 5 cut into 50 mm × 50 mm and the heat conductive sheets according to Comparative Examples 1 to 4 are pressured at 0.5 kgf / cm ² from above and below with SUS plates of the same size. Was fixed with a jig so that it could be maintained.
When the jig to which the heat conductive sheet was fixed was freely dropped from a height of 760 mm, it was judged whether the heat conductive sheet was detached from the jig, and the following evaluation criteria were used. The results are shown in Table 1-1 and Table 1-2.
〔Evaluation criteria〕
○ ・ ・ ・ Does not come off × ・ ・ ・ Removes

  The evaluation results of the thermal resistance value and the volume resistance value are shown in Table 2-1 and Table 2-2. In addition, Table 2-3 shows the measurable range when measuring the volume resistance value.

  The relationship between the load and the thermal resistance value is shown in Table 3 and FIG.

In Examples 1-5, the heat conductive sheet which improved the adhesiveness with respect to a heat source and a heat radiating member, was excellent in heat conductivity, and was excellent also in electrical insulation was obtained.
On the other hand, in Comparative Examples 1 and 2, in the drop test, the result was bad and the adhesion was insufficient.
Moreover, in Comparative Example 2, the volume resistance value was low and the electrical insulation was insufficient.
In Comparative Example 3, a heat conductive sheet could not be obtained because of poor adhesion between the double-sided tape and the heat conductive particle-containing layer.
In Comparative Example 4, the electrical insulation was insufficient when the measurement voltage was increased. Since Comparative Example 4 does not have an insulating resin layer, the adhesive layer and the thermally conductive filler-containing layer (sheet) are laminated, and when the resulting laminate is passed through a pressure-bonding roll, the carbon fibers are adhered to the adhesive layer. It is thought that the volume resistance is reduced by deeply entering the space.

DESCRIPTION OF SYMBOLS 1 Thermal conductive sheet 2 Heat spreader 2a Main surface 2b Side wall 2c Other surface 3 Electronic component 3a Upper surface 5 Heat sink 6 Wiring board 10 Spacer 11 Molded body sheet

Claims (8)

A thermally conductive filler-containing layer containing a binder resin and a thermally conductive filler;
A first adhesive layer containing a first adhesive;
An insulating resin layer containing an insulating resin and having insulating properties;
A second adhesive layer containing a second adhesive;
In this order,
The surface of the thermally conductive filler-containing layer is covered with an exuded component that has exuded from the thermally conductive filler-containing layer so as to follow the protruding shape of the protruding thermal conductive filler. Thermal conductive sheet.   The heat conductive sheet according to claim 1, wherein the binder resin contains an addition reaction type silicone resin.   The heat conductive sheet according to claim 1, wherein the heat conductive filler contains carbon fiber and an inorganic filler.   The heat conductive sheet according to any one of claims 1 to 3, wherein the total average thickness of the first adhesive layer, the insulating resin layer, and the second adhesive layer is 3 µm to 15 µm.   The heat conductive sheet according to any one of claims 1 to 4, wherein the insulating resin layer is a polyethylene terephthalate film. 6. The heat conductive sheet according to claim 1, wherein the volume resistivity at an applied voltage of 500 V, measured according to ASTM-D257, is 1.0 × 10 ¹⁰ Ω · cm or more. It is a manufacturing method of the heat conductive sheet according to any one of claims 1 to 6,
Including a thermally conductive filler-containing layer production step of producing the thermally conductive filler-containing layer,
The said heat conductive filler content layer preparation process contains the process of following (1)-(3), The manufacturing method of the heat conductive sheet characterized by the above-mentioned.
(1) A molded body preparation process for obtaining a molded body of the thermal conductive resin composition by molding and curing a thermal conductive resin composition containing a binder resin and a thermal conductive filler into a predetermined shape.
(2) A molded body sheet preparation process in which the molded body is cut into a sheet shape to obtain a molded body sheet on which the thermally conductive filler protrudes.
(3) A press that presses the molded body sheet and covers the surface of the molded body sheet with an exuding component that has exuded from the molded body sheet so as to follow the protruding shape of the protruding thermal conductive filler. processing. A heat source, a heat radiating member, and a heat conductive sheet sandwiched between the heat source and the heat radiating member,
The semiconductor device according to claim 1, wherein the heat conductive sheet is the heat conductive sheet according to claim 1.