JP2014148094A - Thermal conductive sheet and production method of thermal conductive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a thermal conductive sheet of a structure in which sufficient thermal conductivity is obtained in a thickness direction of the thermal conductive sheet, and a defective fraction of insulation properties related to the thickness direction is reduced.SOLUTION: A thermal conductive sheet 40 includes a first thermal conductive sheet 40a and a second thermal conductive sheet 40b that are mutually laminated and integrated. The first thermal conductive sheet 40a and the second thermal conductive sheet 40b comprise a scaly, spheroid or rod-like thermal conductivity filler 12 included in an organic resin 11 that is formed in a thin film shape and made into a cured state. A dimension of the thermal conductivity filler 12 in a thickness direction of the first thermal conductive sheet 40a and the second thermal conductive sheet 40b is larger than a dimension of the thermal conductivity filler 12 in a surface direction of the first thermal conductive sheet 40a and the second thermal conductive sheet 40b.

Description

  The present invention relates to a heat conductive sheet and a method for manufacturing the heat conductive sheet.

  2. Description of the Related Art A heat conductive sheet is known that is provided at a bonding interface that requires high thermal conductivity, such as between a heat generator (such as a semiconductor chip) and a heat radiator (such as a heat sink).

  Patent Document 1 describes a heat conductive sheet having insulation in the thickness direction. This heat conductive sheet is constituted by laminating two or more layers including the layer A and the layer B in the sheet thickness direction. The layer A is made of a composition containing insulating non-spherical particles and an organic polymer compound, and the insulating non-spherical particles are oriented in the thickness direction of the layer A. Layer B is made of an insulating resin composition.

JP 2011-230472 A

  However, if a defect is locally generated in the surface direction of the heat conductive sheet for some reason (for example, contamination of foreign matter) and the insulation in the defective portion is impaired, the heat conductive sheet It becomes the structure which mutually short-circuited (short-circuit), and the insulation in the thickness direction of a heat conductive sheet cannot be obtained.

  The present invention has been made in view of the above problems, and provides a thermal conductive sheet having a structure having sufficient thermal conductivity in the thickness direction and a reduced defect rate regarding insulation in the thickness direction, and a method for manufacturing the same. To do.

The present invention is a first heat conductive sheet comprising a scale-like, oval or rod-like first heat conductive filler in a first organic resin formed into a thin film and cured. A first heat conductive sheet in which the dimension of the first heat conductive filler in the thickness direction of the first heat conductive sheet is larger than the dimension of the first heat conductive filler in the surface direction of the first heat conductive sheet;
A second heat conductive sheet comprising a second heat conductive filler having a scale shape, an oval shape or a rod shape in a second organic resin formed into a thin film and in a cured state, the second heat conduction A second heat conductive sheet in which the dimension of the second heat conductive filler in the thickness direction of the sheet is larger than the dimension of the second heat conductive filler in the surface direction of the second heat conductive sheet;
Have
Provided is a heat conductive sheet in which the first heat conductive sheet and the second heat conductive sheet are laminated and integrated with each other.

  This heat conductive sheet is configured by laminating and integrating a first heat conductive sheet and a second heat conductive sheet. For this reason, a heat conductive sheet has sufficient heat conductivity and insulation in the thickness direction. The reason will be described below.

First, the dimension of the 1st heat conductive filler in the thickness direction of a 1st heat conductive sheet is larger than the dimension of the 1st heat conductive filler in the surface direction of a 1st heat conductive sheet. That is, in the 1st heat conductive sheet, the 1st heat conductive filler is orientated in the thickness direction of the 1st heat conductive sheet. Therefore, good thermal conductivity in the thickness direction of the first heat conductive sheet can be obtained.
Similarly, the dimension of the 2nd heat conductive filler in the thickness direction of a 2nd heat conductive sheet is larger than the dimension of the 2nd heat conductive filler in the surface direction of a 2nd heat conductive sheet. That is, in the second heat conductive sheet, the second heat conductive filler is oriented in the thickness direction of the second heat conductive sheet. Therefore, good thermal conductivity in the thickness direction of the second heat conductive sheet is obtained.
Furthermore, the 1st heat conductive sheet and the 2nd heat conductive sheet are mutually laminated | stacked and integrated, and the heat conductive sheet is comprised. For this reason, the 1st heat conductive filler and the 2nd heat conductive filler are orientated in the thickness direction of a heat conductive sheet. Therefore, the favorable heat conductivity in the thickness direction of a heat conductive sheet is obtained. That is, heat is applied between the surface of the first heat conductive sheet opposite to the second heat conductive sheet side and the surface of the second heat conductive sheet opposite to the first heat conductive sheet side. It can be suitably transmitted.

  Here, let us consider a case where a defect is locally generated in the surface direction of the first heat conductive sheet and the insulation at the defective portion is impaired. In this case, the first heat conductive sheet has a structure in which the front and back surfaces are locally short-circuited to each other. However, the 2nd heat conductive sheet is laminated | stacked on the 1st heat conductive sheet. Therefore, the short circuit part in the 1st heat conductive sheet is covered with the 2nd heat conductive sheet. For this reason, in the whole heat conductive sheet including the first heat conductive sheet and the second heat conductive sheet, there is a high possibility that sufficient insulation is obtained in the thickness direction of the heat conductive sheet. In other words, as long as the short circuit part in the 1st heat conductive sheet and the short circuit part in the 2nd heat conductive sheet do not overlap up and down, it is thought that sufficient insulation in the thickness direction of a heat conductive sheet is acquired.

Suppose that in a single-layer heat conductive sheet (each of the first heat conductive sheet and the second heat conductive sheet), the possibility that the front and back surfaces short-circuit each other is 1%. In this case, the defect rate of the single-layer heat conductive sheet is 1%.
Furthermore, in this case, in the single-layer heat conduction sheet (each of the first heat conduction sheet and the second heat conduction sheet) in which a short circuit occurs, the portion of the front and back surfaces that are short-circuited (referred to as a short circuit portion) Assume that the area ratio is 1%. In this case, when the 1st heat conductive sheet and the 2nd heat conductive sheet in which the short circuit has arisen are laminated | stacked, the probability that the short circuit part in a 1st heat conductive sheet and the short circuit part in a 2nd heat conductive sheet will overlap up and down, respectively. Is 1%.
The conditions under which the heat conductive sheet including the first heat conductive sheet and the second heat conductive sheet are defective are as follows: (1) a defect occurs in the first heat conductive sheet, and (2) a defect occurs in the second heat conductive sheet. And (3) the short-circuit portion in the first heat conductive sheet and the short-circuit portion in the second heat conductive sheet overlap vertically. For this reason, in this case, the defect rate of the heat conductive sheet including the first heat conductive sheet and the second heat conductive sheet is 1% × 1% × 1% = 0.0001%.
Thus, by making a heat conductive sheet into the laminated structure of a 1st heat conductive sheet and a 2nd heat conductive sheet, compared with the case where a heat conductive sheet is a single layer structure, it is related with ensuring insulation in the thickness direction. The defect rate can be significantly reduced. As an example, in the case of the above model, the defect rate can be reduced to 1/10000.

  Thus, according to this heat conductive sheet, it is possible to achieve a structure in which sufficient heat conductivity is obtained in the thickness direction and the defect rate regarding insulation in the thickness direction is reduced.

Moreover, this invention is a 1st heat conductive sheet which contains the 1st heat conductive filler of a scale shape, an oval shape, or a rod shape in the 1st organic resin formed into the thin film form, and was made into the hardening state, The first heat conductive sheet is larger in the dimension of the first heat conductive filler in the thickness direction of the first heat conductive sheet than the dimension of the first heat conductive filler in the surface direction of the first heat conductive sheet. A manufacturing process;
A second heat conductive sheet comprising a second heat conductive filler having a scale shape, an oval shape or a rod shape in a second organic resin formed into a thin film and in a cured state, the second heat conduction Producing a second heat conductive sheet in which the dimension of the second heat conductive filler in the thickness direction of the sheet is larger than the dimension of the second heat conductive filler in the surface direction of the second heat conductive sheet;
Laminating and integrating the first heat conductive sheet and the second heat conductive sheet;
The manufacturing method of the heat conductive sheet which has this is provided.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to obtain sufficient heat conductivity in the thickness direction of a heat conductive sheet, the heat conductive sheet of the structure where the defect rate regarding the insulation of the thickness direction was reduced is realizable.

It is typical sectional drawing of the heat conductive sheet which concerns on 1st Embodiment. Each of FIGS. 2A to 2I is a schematic view showing a molded product in each step in the method for manufacturing a heat conductive sheet according to the first embodiment. It is typical sectional drawing of the heat conductive sheet which concerns on 2nd Embodiment. It is typical sectional drawing of the heat conductive sheet which concerns on 3rd Embodiment. FIGS. 5A to 5C are schematic views showing a heat conductive sheet according to the fourth embodiment, in which (a) is a perspective view, (b) is a front view, and (c). FIG. 3 is an enlarged cross-sectional view of part A in (b). Each figure of Drawing 6 (a)-(k) is a mimetic diagram showing a molding by each process in a manufacturing method of a heat conduction sheet concerning a 4th embodiment. FIGS. 7A to 7C are schematic views showing a heat conductive sheet according to the fifth embodiment, in which (a) is a perspective view, (b) is a front view, and (c). FIG. 3 is an enlarged cross-sectional view of part A in (b). Each of FIGS. 8A to 8H is a schematic diagram showing a molded product in each step in the method for manufacturing a heat conductive sheet according to the fifth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[First Embodiment]
FIG. 1 is a schematic cross-sectional view of a heat conductive sheet 40 according to the first embodiment.

  The heat conductive sheet 40 according to the present embodiment includes a first heat conductive sheet 40a and a second heat conductive sheet 40b. The heat conductive sheet 40 has insulation in the thickness direction.

  The first heat conductive sheet 40a is formed in a thin film-like organic resin 11 (first organic resin) and is in a scale-like, oval or rod-like heat conductive filler 12 (first heat conductive). Filler).

  The dimension of the heat conductive filler 12 in the thickness direction (vertical direction in FIG. 1) of the first heat conductive sheet 40a is the dimension of the heat conductive filler 12 in the surface direction (left and right direction in FIG. 1) of the first heat conductive sheet 40a. Bigger than. That is, the heat conductive filler 12 is oriented in the thickness direction (vertical direction in FIG. 1) of the first heat conductive sheet 40a.

  Here, the dimension of the heat conductive filler 12 in the thickness direction of the first heat conductive sheet 40a refers to the heat conductive filler 12 in the first heat conductive sheet 40a in the surface direction (thickness direction) of the first heat conductive sheet 40a. It is the maximum dimension when projected in a direction orthogonal to. Moreover, the dimension of the heat conductive filler 12 in the surface direction of the 1st heat conductive sheet 40a is the thickness direction (in a surface direction) of the heat conductive filler 12 in the 1st heat conductive sheet 40a. It is the maximum dimension when projected in a direction orthogonal to the above.

  The orientation of the heat conductive filler 12 referred to here means that all the heat conductive fillers 12 in the first heat conductive sheet 40a are necessarily oriented in the thickness direction of the first heat conductive sheet 40a. Not a translation. For example, 60% or more of the heat conductive filler 12 in the first heat conductive sheet 40a is oriented in the thickness direction of the first heat conductive sheet 40a, and the heat conductive filler 12 in the first heat conductive sheet 40a. 70% or more is oriented in the thickness direction of the first heat conductive sheet 40a, or 80% or more of the heat conductive filler 12 in the first heat conductive sheet 40a is in the thickness direction of the first heat conductive sheet 40a. It means that the heat conductive filler 12 in a certain ratio or more (but more than half) in the first heat conductive sheet 40a is oriented in the thickness direction of the first heat conductive sheet 40a, such as being oriented.

  For example, the aspect ratio of the heat conductive filler 12 in the first heat conductive sheet 40a (the dimension of the heat conductive filler 12 in the thickness direction of the first heat conductive sheet 40a / the heat conductivity in the surface direction of the first heat conductive sheet 40a). The shape of the thermally conductive filler 12 is selected and the orientation of the thermally conductive filler 12 is set so that the average value of the dimensions of the filler 12 is 2 or more, preferably 5 or more. desirable.

  The second heat conductive sheet 40b is the same as the first heat conductive sheet 40a. That is, the second heat conductive sheet 40b is formed in a thin film-like organic resin 11 (second organic resin) and has a scaly, oval or rod-like heat conductive filler 12 (second heat A conductive filler).

  The dimension of the heat conductive filler 12 in the thickness direction (vertical direction in FIG. 1) of the second heat conductive sheet 40b is the dimension of the heat conductive filler 12 in the surface direction (horizontal direction in FIG. 1) of the second heat conductive sheet 40b. Bigger than. That is, the heat conductive filler 12 is oriented in the thickness direction (vertical direction in FIG. 1) of the second heat conductive sheet 40b.

  Here, the dimension of the heat conductive filler 12 in the thickness direction of the second heat conductive sheet 40b refers to the heat conductive filler 12 in the second heat conductive sheet 40b in the surface direction (thickness direction) of the second heat conductive sheet 40b. It is the maximum dimension when projected in a direction orthogonal to. Moreover, the dimension of the heat conductive filler 12 in the surface direction of the 2nd heat conductive sheet 40b is the thickness direction (in a surface direction) of the heat conductive filler 12 in the 2nd heat conductive sheet 40b. It is the maximum dimension when projected in a direction orthogonal to the above.

  In addition, the orientation of the heat conductive filler 12 said here means that all the heat conductive fillers 12 in the 2nd heat conductive sheet 40b are orientated in the thickness direction of the 2nd heat conductive sheet 40b. Not a translation. For example, 60% or more of the heat conductive filler 12 in the second heat conductive sheet 40b is oriented in the thickness direction of the second heat conductive sheet 40b, and the heat conductive filler 12 in the second heat conductive sheet 40b. 70% or more is oriented in the thickness direction of the second heat conductive sheet 40b, or 80% or more of the heat conductive filler 12 in the second heat conductive sheet 40b is in the thickness direction of the second heat conductive sheet 40b. It means that the heat conductive filler 12 in a certain ratio or more (but more than half) in the second heat conductive sheet 40b is oriented in the thickness direction of the second heat conductive sheet 40b, such as being oriented.

  For example, the aspect ratio of the heat conductive filler 12 in the second heat conductive sheet 40b (the dimension of the heat conductive filler 12 in the thickness direction of the second heat conductive sheet 40b / the heat conductivity in the surface direction of the second heat conductive sheet 40b). The shape of the thermally conductive filler 12 is selected and the orientation of the thermally conductive filler 12 is set so that the average value of the dimensions of the filler 12 is 2 or more, preferably 5 or more. desirable.

  The 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b are laminated | stacked mutually, and are mutually integrated, and the heat conductive sheet 40 is comprised.

  For example, the first heat conductive sheet 40 a and the second heat conductive sheet 40 b are integrated by being bonded to each other through the adhesive layer 50. In addition, the interface exists between the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b. For example, the interface between the adhesive layer 50 and the first heat conductive sheet 40a and the interface between the adhesive layer 50 and the second heat conductive sheet 40b are the first heat conductive sheet 40a and the second heat conductive sheet 40b. Exists between.

  The heat conductive filler 12 has good heat conductivity, is maintained in a predetermined shape even after the curing treatment of the organic resin 11, and is insulative.

  The heat conductive filler 12 has a scaly shape, an elliptical shape, or a rod shape. More specifically, for example, the thermally conductive filler 12 is a hexagonal boron nitride particle or graphite in which the hexagonal plane in the crystal is oriented in the scale surface direction, the long axis direction of the ellipse, or the axial direction of the rod. Particles. Alternatively, the heat conductive filler 12 may be scaly alumina. The average of the particle diameter of the thermally conductive filler 12 (the maximum dimension of individual particles of the thermally conductive filler 12) can be, for example, 1 μm or more and 150 μm or less.

  The heat conductive filler 12 in the first heat conductive sheet 40a and the heat conductive filler 12 in the second heat conductive sheet 40b may be of the same type or of different types. It may be.

  The organic resin 11 may be an epoxy resin, polyimide or benzoxazine. The epoxy resin may be either bisphenol A type or bisphenol F type. The epoxy resin contains an imidazole, an amine or a phenol compound as a curing agent.

  The organic resin 11 constituting the first heat conductive sheet 40a and the organic resin 11 constituting the second heat conductive sheet 40b may be of the same type or different types. May be.

  The adhesive layer 50 is made of, for example, an epoxy resin or a polyimide containing a curing agent.

  The thickness of the heat conductive sheet 40 can be, for example, 50 μm or more and 250 μm or less, and preferably about 180 μm. In addition, the thickness of the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b can be about half of the thickness of the heat conductive sheet 40, respectively. However, the thickness of the first heat conductive sheet 40a and the thickness of the second heat conductive sheet 40b may be different from each other.

  The heat conductive sheet 40 is provided at a bonding interface where high heat conductivity is required, for example, between a heat generator (such as a semiconductor chip) and a heat radiator (such as a heat sink), and from the heat generator to the heat radiator. Promotes heat conduction. As an example of a specific semiconductor device structure having the heat conductive sheet 40, for example, a semiconductor chip is mounted on a wiring board (interposer), and the wiring board is mounted on a heat sink. The structure which provided the heat conductive sheet 40 in the joining interface of a wiring board and a joining interface of a wiring board and a heat sink is mentioned, respectively. In this case, the semiconductor chip and the wiring board are insulated from each other by the heat conductive sheet 40, and the wiring board and the heat sink are insulated from each other by the heat conductive sheet 40.

  Next, an example of a method for manufacturing the heat conductive sheet 40 having the above structure will be described.

  Each of FIGS. 2A to 2I is a schematic view showing a molded product in each step in the method for manufacturing a heat conductive sheet according to the first embodiment.

This manufacturing method includes the following steps (1) to (3).
(1) In the 1st organic resin (organic resin 11) formed in the thin film form and made into the cured state, the scale-like, oval or rod-like 1st heat conductive filler (heat conductive filler 12) is included. The process of producing the 1st heat conductive sheet 40a which becomes (FIGS. 2A to 2D)
Here, the first heat conductive filler 40 in the thickness direction of the first heat conductive sheet 40a is larger than the first heat conductive filler in the surface direction of the first heat conductive sheet 40a. Orient the thermally conductive filler.
(2) In the second organic resin (organic resin 11) formed into a thin film and in a cured state, a scaly, oval or rod-shaped second heat conductive filler (thermal conductive filler 12) is included. The process of producing the 2nd heat conductive sheet 40b which becomes (FIG.2 (e)-(h))
Here, the second heat conductive filler 40b in the thickness direction of the second heat conductive sheet 40b is larger than the second heat conductive filler in the surface direction of the second heat conductive sheet 40b. Orient the thermally conductive filler.
(3) Step of laminating and integrating the first heat conductive sheet 40a and the second heat conductive sheet 40b (FIG. 2 (i))
Details will be described below.

  First, a thermally conductive filler 12 and an organic resin 11 that are materials of the first sheet 10 (FIG. 2A) are prepared.

  Next, the organic resin 11 before curing and before semi-curing and a large number of thermally conductive fillers 12 are mixed and kneaded so that the thermally conductive fillers 12 are uniformly present in the organic resin 11. Hereinafter, what was obtained by kneading the organic resin 11 and a large number of thermally conductive fillers 12 is referred to as a kneaded product.

  Next, the first sheet 10 is produced. The 1st sheet | seat 10 is obtained by shape | molding the said kneaded material, ie, the organic resin 11 containing the heat conductive filler 12, in the shape of a thin film, and semi-hardening the said organic resin 11. FIG. When an epoxy resin or polyimide is used as the organic resin 11, the first sheet 10 is obtained by forming the organic resin 11 into a thin film shape and then using the organic resin 11 as a B stage.

  Here, the kneaded product is formed into a thin film shape by press molding or the like. Thereby, the dimension in the 1st sheet | seat 10 is larger so that the dimension of the heat conductive filler 12 in the surface direction of the 1st sheet | seat 10 may become larger than the dimension of the heat conductive filler 12 in the thickness direction of the 1st sheet | seat 10. The thermally conductive filler 12 is oriented. Hereinafter, orienting the thermally conductive filler 12 in such a direction is referred to as orienting in the plane direction.

  For example, the aspect ratio of the thermally conductive filler 12 in the first sheet 10 (the dimension of the thermally conductive filler 12 in the thickness direction of the first sheet 10 / the dimension of the thermally conductive filler 12 in the plane direction of the first sheet 10). It is desirable to select the shape of the thermally conductive filler 12 and set the orientation of the thermally conductive filler 12 so that the average value is 1/2 or less, preferably 1/5 or less.

  In addition, the orientation of the heat conductive filler 12 said here does not necessarily mean that all the heat conductive fillers 12 in the 1st sheet | seat 10 are orientated in the surface direction. For example, 60% or more of the heat conductive filler 12 in the first sheet 10 is oriented in the plane direction, and 70% or more of the heat conductive filler 12 in the first sheet 10 is oriented in the plane direction. Or 80% or more of the heat conductive filler 12 in the first sheet 10 is oriented in the plane direction, etc., a certain percentage or more (however, more than half) of the heat conductive filler in the first sheet 10 This means that 12 is oriented in the plane direction.

  In addition, the method of shape | molding the said kneaded material into a thin film shape is not restricted to press molding, Roll molding, extrusion molding, or coating molding may be sufficient.

  When the kneaded product is formed into a thin film shape, or after the kneaded product is formed into a thin film shape, the organic resin 11 constituting the first sheet 10 is heated to a first predetermined temperature to thereby form the organic resin. 11 is in a semi-cured state. That is, when an epoxy resin or polyimide is used as the organic resin 11, the organic resin 11 is set to the B stage. Specifically, the organic resin 11 constituting the first sheet 10 can be made into a semi-cured state while forming the kneaded material into a thin film shape by, for example, pressing while heating. Thereby, the 1st sheet | seat 10 is obtained (FIG. 2 (a)). At this time, in order to improve the flatness of the first sheet 10, for example, it is preferable to heat-press the first sheet 10 using a pair of flat heating and pressing plates. The thickness of the 1st sheet | seat 10 can be 50 micrometers or more and 2 mm or less, for example.

  Next, a plurality of first sheets 10 are stacked (FIG. 2B).

  Next, the laminated first sheets 10 are pressed (heated and pressed) in the laminating direction. At this time, the organic resin 11 is heated to a second predetermined temperature higher than the first predetermined temperature. Thereby, the organic resin 11 which comprises the 1st sheet | seat 10 is hardened. That is, when an epoxy resin or polyimide is used as the organic resin 11, the organic resin 11 is set to the C stage. Thereby, adjacent 1st sheet | seats 10 mutually integrate, and the 1st laminated body 30a of a rectangular parallelepiped shape is shape | molded (FIG.2 (c)).

  Next, by cutting (slicing) the first laminated body 30a in the laminating direction of the first sheet 10 constituting the first laminated body 30a (vertical direction in FIG. 2C), the first heat conductive sheet 40a is obtained. It is manufactured (FIG. 2D). Here, as a method of slicing the first stacked body 30a, a method of slicing using a plane or a method of slicing with other cutting blades may be mentioned.

  Accordingly, the first heat conduction is performed such that the dimension of the heat conductive filler 12 in the thickness direction of the first heat conductive sheet 40a is larger than the dimension of the heat conductive filler 12 in the surface direction of the first heat conductive sheet 40a. The thermally conductive filler 12 in the sheet 40a is oriented. That is, the heat conductive filler 12 is oriented in the thickness direction of the first heat conductive sheet 40a.

  On the other hand, in the same manner as the process of manufacturing the first stacked body 30a (FIGS. 2A to 2C), the same processes as those of the first stacked body 30a are performed by performing the processes of FIGS. The 2nd laminated body 30b is produced.

  Next, by cutting (slicing) the second laminated body 30b in the laminating direction of the first sheet 10 constituting the second laminated body 30b (vertical direction in FIG. 2G), the second heat conductive sheet 40b is obtained. It is produced (FIG. 2 (h)). The method of slicing the second stacked body 30b is the same as the method of slicing the first stacked body 30a. In this way, the 2nd heat conductive sheet 40b of the structure similar to the 1st heat conductive sheet 40a is obtained.

  Next, as shown in FIG. 2 (i), the first heat conductive sheet 40a and the second heat conductive sheet 40b are laminated and integrated with each other. Specifically, for example, the first heat conductive sheet 40a and the second heat conductive sheet 40b are integrated by bonding to each other through the adhesive layer 50. Thereby, the heat conductive sheet 40 is obtained.

  In addition, although the example which produces separately the 1st laminated body 30a for obtaining the 1st heat conductive sheet 40a and the 2nd laminated body 30b for obtaining the 2nd heat conductive sheet 40b was demonstrated here, it is the same. You may obtain both the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b from the laminated body (for example, 1st laminated body 30a).

  According to the first embodiment as described above, the heat conductive sheet 40 is configured by laminating and integrating the first heat conductive sheet 40a and the second heat conductive sheet 40b. For this reason, the heat conductive sheet 40 has sufficient heat conductivity and insulation in the thickness direction. The reason will be described below.

First, the dimension of the heat conductive filler 12 in the thickness direction of the first heat conductive sheet 40a is larger than the dimension of the heat conductive filler 12 in the surface direction of the first heat conductive sheet 40a. That is, in the first heat conductive sheet 40a, the heat conductive filler 12 is oriented in the thickness direction of the first heat conductive sheet 40a. Therefore, the favorable heat conductivity in the thickness direction of the 1st heat conductive sheet 40a is obtained.
Similarly, the dimension of the heat conductive filler 12 in the thickness direction of the second heat conductive sheet 40b is larger than the dimension of the heat conductive filler 12 in the surface direction of the second heat conductive sheet 40b. That is, in the second heat conductive sheet 40b, the heat conductive filler 12 is oriented in the thickness direction of the second heat conductive sheet 40b. Therefore, the favorable heat conductivity in the thickness direction of the 2nd heat conductive sheet 40b is obtained.
Furthermore, the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b are mutually laminated | stacked and integrated, and the heat conductive sheet 40 is comprised. For this reason, the heat conductive filler 12 in the 1st heat conductive sheet 40a and the heat conductive filler 12 in the 2nd heat conductive sheet 40b are orientated in the thickness direction of the heat conductive sheet 40. Therefore, good thermal conductivity in the thickness direction of the heat conductive sheet 40 is obtained. That is, between the surface opposite to the second heat conductive sheet 40b side in the first heat conductive sheet 40a and the surface opposite to the first heat conductive sheet 40a side in the second heat conductive sheet 40b. In addition, heat can be suitably transmitted.

  Here, let us consider a case where a defect is locally generated in the surface direction of the first heat conductive sheet 40a and the insulation at the defective portion is impaired. In this case, the 1st heat conductive sheet 40a is the structure where the surface of the front and back was short-circuited mutually. However, the 2nd heat conductive sheet 40b is laminated | stacked on the 1st heat conductive sheet 40a. Therefore, the short circuit part in the 1st heat conductive sheet 40a is covered with the 2nd heat conductive sheet 40b. For this reason, in the whole heat conductive sheet 40 including the first heat conductive sheet 40a and the second heat conductive sheet 40b, there is a high possibility that sufficient insulation is obtained in the thickness direction of the heat conductive sheet 40. In other words, as long as the short circuit part in the 1st heat conductive sheet 40a and the short circuit part in the 2nd heat conductive sheet 40b do not overlap up and down, sufficient insulation in the thickness direction of the heat conductive sheet 40 is obtained. Conceivable.

Temporarily, in the single-layer heat conductive sheet (each of the first heat conductive sheet 40a and the second heat conductive sheet 40b), the possibility that the front and back surfaces short-circuit each other is 1%. In this case, the defect rate of the single-layer heat conductive sheet is 1%.
Furthermore, in this case, in the single-layer heat conduction sheet (each of the first heat conduction sheet 40a and the second heat conduction sheet 40b) in which a short circuit occurs, a portion where the front and back surfaces are short-circuited (referred to as a short-circuit portion). ) Is 1%. In this case, when the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b which have each short-circuited are laminated | stacked, the short circuit part in the 1st heat conductive sheet 40a and the short circuit part in the 2nd heat conductive sheet 40b become. The probability of overlapping vertically is 1%.
The conditions under which the heat conductive sheet 40 including the first heat conductive sheet 40a and the second heat conductive sheet 40b are defective are as follows: (1) a defect occurs in the first heat conductive sheet 40a; (2) second heat conduction A defect occurs in the sheet 40b, and (3) the short-circuit portion in the first heat conductive sheet 40a and the short-circuit portion in the second heat conductive sheet 40b overlap vertically. For this reason, in this case, the defect rate of the heat conductive sheet 40 including the first heat conductive sheet 40a and the second heat conductive sheet 40b is 1% × 1% × 1% = 0.0001%.
Thus, by making the heat conductive sheet 40 into the laminated structure of the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b, compared with the case where the heat conductive sheet 40 is a single layer structure, insulation in the thickness direction is carried out. It is possible to remarkably reduce the defect rate related to securing the property. That is, as an example, in the case of the model described here, the defect rate can be reduced to 1/10000.

  Thus, according to the present embodiment, the thermal conductive sheet 40 having a structure in which sufficient thermal conductivity is obtained in the thickness direction of the thermal conductive sheet 40 and the defect rate regarding the insulation in the thickness direction is reduced is realized. be able to.

[Second Embodiment]
FIG. 3 is a schematic cross-sectional view of a heat conductive sheet 40 according to the second embodiment. The heat conductive sheet 40 according to the present embodiment is different from the heat conductive sheet 40 according to the first embodiment described above in the points described below, and is otherwise the heat conductive sheet according to the first embodiment. 40 is configured in the same manner.

  In the present embodiment, the adhesive layer 50 includes a heat conductive filler (third heat conductive filler) 51. The shape of the heat conductive filler 51 is arbitrary. The shape of the heat conductive filler 51 can be, for example, spherical, elliptical, rod-like, or scale-like.

  The thermally conductive filler 51 has good thermal conductivity, and is maintained in a predetermined shape even after the adhesive layer 50 is cured, and is insulative. Examples of the material of the heat conductive filler 51 include inorganic particles such as silica or alumina. The average of the particle size of the thermal conductive filler 51 (the maximum dimension of individual particles of the thermal conductive filler 51) can be, for example, 1 μm or more and 150 μm or less.

  In the case of this embodiment, the method of manufacturing the heat conductive sheet 40 is different from the first embodiment in that an adhesive including the heat conductive filler 51 is used as the adhesive constituting the adhesive layer 50. Other points are the same as in the first embodiment.

  According to the present embodiment, the same effects as those of the first embodiment can be obtained, and since the adhesive layer 50 includes the heat conductive filler 51, the first heat conductive sheet 40a and the second heat conductive sheet. The thermal conductivity between each other and 40b can be further improved.

[Third Embodiment]
FIG. 4 is a schematic cross-sectional view of a main part showing a heat conductive sheet 40 according to the third embodiment. The heat conductive sheet 40 according to the present embodiment is different from the heat conductive sheet 40 according to the first or second embodiment described above in the points described below, and otherwise the first or second implementation. It is comprised similarly to the heat conductive sheet 40 which concerns on a form.

  In the case of the present embodiment, the heat conductive sheet 40 includes an insulating layer 45 formed on at least one of the front and back surfaces in addition to the configuration shown in FIG. 1 or FIG. This insulating layer 45 is provided in order to obtain better insulating properties in the thickness direction of the heat conductive sheet 40. Further, the insulating layer 45 can improve the adhesion of the heat conductive sheet 40 to the installation surface of the heat conductive sheet 40. FIG. 4 shows an example in which insulating layers 45 are formed on both the front and back surfaces of the heat conductive sheet 40.

  Examples of the material of the insulating layer 45 include (meth) acrylic acid esters such as butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate.

  The thickness of the insulating layer 45 is thinner than the thickness of the heat conductive sheet 40 excluding the insulating layer 45. The thickness of the insulating layer 45 can be, for example, 5 μm or more and 20 μm or less, and preferably about 10 μm.

  According to the present embodiment, the same effects as those of the first or second embodiment can be obtained. Moreover, since the heat conductive sheet 40 has the insulating layer 45 formed on at least one of the front and back surfaces, it is possible to achieve better insulation in the thickness direction of the heat conductive sheet 40. it can.

[Fourth Embodiment]
FIGS. 5A to 5C are schematic views showing a heat conductive sheet 40 according to the fourth embodiment, in which (a) is a perspective view, (b) is a front view, and (c). ) Is an enlarged cross-sectional view of part A of (b). The heat conductive sheet 40 according to the present embodiment is different from the heat conductive sheet 40 according to the first to third embodiments in the points described below, and the other points are the same as those in the first to third embodiments. It is comprised similarly to the heat conductive sheet 40 which concerns.

  In the case of the present embodiment, at least one of the first heat conductive sheet 40a and the second heat conductive sheet 40b is partitioned into a plurality of regions (a quadratic prism-shaped portion 41 described later) in the plane direction, A partition portion (adhesive layer made of an adhesive 15 to be described later) for partitioning adjacent regions is formed between adjacent regions among the plurality of regions.

  The first heat conductive sheet 40 a has a plurality of quadrangular columnar portions 41 made of the organic resin 11 including the heat conductive filler 12.

  The plurality of quadrangular prism-shaped portions 41 are long in each axial direction (a direction connecting the center of the bottom surface and the center of the top surface in the quadrangular prism shape). The plurality of quadrangular prism-shaped portions 41 are arranged along the surface direction of the first heat conductive sheet 40a so as to be parallel to each other (in the left-right direction in FIGS. 5A to 5C), and adjacent four The side surfaces of the prismatic portion 41 are joined through an adhesive layer made of the adhesive 15 to form a single sheet.

  The adhesive 15 is made of, for example, an epoxy resin or a polyimide containing a curing agent. It is preferable that the heat conductive filler 12 is not present inside the adhesive layer.

  In addition, it is the direction (right-and-left direction of FIG. 5 (a)-(c)) in the direction orthogonal to the axial direction of the quadratic prism-shaped part 41, and in the surface direction of the 1st heat conductive sheet 40a. The dimension of the quadrangular prism-shaped portion 41 in FIG.

  As shown in FIG. 5C, in each of the plurality of quadrangular columnar portions 41, the heat conductive filler 12 is oriented in the thickness direction of the first heat conductive sheet 40a (vertical direction in FIG. 5C). Yes.

  As described above, the first heat conductive sheet 40a is partitioned into a plurality of regions (quadrangular columnar portions 41) in the plane direction, and regions adjacent to each other among the regions adjacent to each other among the regions. A partition part (adhesive layer made of the adhesive 15) for partitioning each other is formed.

  For example, similarly to the first heat conductive sheet 40a, the second heat conductive sheet 40b is partitioned into a plurality of regions (quadrangular columnar portions 41) in the plane direction, and between adjacent regions among the plurality of regions. A partition portion (adhesive layer made of the adhesive 15) that partitions adjacent regions is formed.

  Next, an example of a method for manufacturing the heat conductive sheet 40 having the above structure will be described.

  Each figure of Drawing 6 (a)-(k) is a mimetic diagram showing a molding by each process in a manufacturing method of a heat conduction sheet concerning a 4th embodiment.

  First, a plurality of first sheets 10 are produced as in the first embodiment (FIG. 6A). However, in this embodiment, the organic resin 11 constituting the first sheet 10 is not in a semi-cured state but in a cured state. That is, when an epoxy resin or polyimide is used as the organic resin 11, after the organic resin 11 is formed into a thin film shape (or simultaneously with the thin film shape), the organic resin 11 is changed to the C stage, so that the first Sheet 10 is obtained.

  Next, the adhesive 15 is applied to the first sheet 10 (FIG. 6B). Here, the adhesive 15 may be applied to the entire surface of one side of the first sheet 10, or the adhesive 15 may be applied to the entire surface of both surfaces of the first sheet 10. Alternatively, the adhesive 15 may be applied in a spot manner to a plurality of locations on one side or both sides of the first sheet 10. Or you may affix the adhesive agent 15 previously formed in the sheet form on the single side | surface or both surfaces of the 1st sheet | seat 10. FIG. In addition, about the 1st sheet | seat 10 used as the uppermost layer or lowermost layer of the 1st laminated body 30a, it is not necessary to apply | coat (or stick) the adhesive agent 15. FIG. As the adhesive 15, for example, an epoxy resin or polyimide containing a curing agent is used.

  Next, the plurality of first sheets 10 are stacked such that the adhesive 15 is positioned between the adjacent first sheets 10 (FIG. 6C).

  Next, the adhesive 15 is cured by pressing the laminated first sheets 10 in the laminating direction (heating and pressing). Thereby, the adjacent 1st sheet | seats 10 are mutually integrated through the adhesive agent 15, and the 1st laminated body 30a of a rectangular parallelepiped shape is shape | molded (FIG.6 (d)).

  Next, the 1st laminated body 30a is cut | disconnected (sliced) in the lamination direction of the 1st sheet | seat 10, and the 1st heat conductive sheet 40a is produced (FIG.6 (e)). Thereby, it will be in the state in which the heat conductive filler 12 was orientated in the thickness direction in the 1st heat conductive sheet 40a. The quadrangular columnar portion 41 is formed of a part of the first sheet 10.

  On the other hand, in the same manner as the process of manufacturing the first stacked body 30a (FIGS. 6A to 6D), the same processes as those of the first stacked body 30a are performed by performing the processes of FIGS. The second stacked body 30b (FIG. 6 (i)) is produced.

  Next, by cutting (slicing) the second stacked body 30b in the stacking direction (the vertical direction in FIG. 6 (i)) of the first sheet 10 constituting the second stacked body 30b, the second heat conductive sheet 40b is formed. It is produced (FIG. 6 (j)). Thus, the second heat conductive sheet 40b having the same configuration as that of the first heat conductive sheet 40a (FIG. 6E) is obtained.

  Next, as shown in FIG. 6 (k), the first heat conductive sheet 40a and the second heat conductive sheet 40b are laminated and integrated with each other. Specifically, for example, the first heat conductive sheet 40a and the second heat conductive sheet 40b are integrated by bonding to each other through the adhesive layer 50. Thereby, the heat conductive sheet 40 is obtained. Note that the adhesive layer 50 may include a thermally conductive filler 51 as in the second embodiment. Moreover, the heat conductive sheet 40 may have the insulating layer 45 similar to 3rd Embodiment.

  According to the fourth embodiment as described above, the following effects can be obtained in addition to the same effects as those of the first to third embodiments.

  In the case of the present embodiment, at least one of the first heat conductive sheet 40a and the second heat conductive sheet 40b is partitioned into a plurality of regions (square columnar portions 41) in the surface direction, A partition portion (adhesive layer made of the adhesive 15) that partitions adjacent regions is formed between adjacent regions among the regions. The heat conductive sheet 40 having such a configuration exhibits good heat conductivity in the thickness direction because the heat conductive filler 12 is oriented in the thickness direction of the heat conductive sheet 40 in each square columnar portion 41. It can be said that the product can be manufactured with high production yield and high yield. In addition, the partition portion regulates the disorder of the orientation of the heat conductive filler 12 due to the movement of the heat conductive filler 12 of the quadrangular columnar portion 41 toward the adjacent quadrangular columnar portion 41 side, whereby the heat conductive filler 12 functions to maintain the orientation. Thereby, the orientation of the heat conductive filler 12 in the heat conductive sheet 40 can be favorably maintained.

In the case of the present embodiment, the first sheet 10 including the thermally conductive filler 12 in the cured organic resin 11 is laminated via the adhesive 15 and integrated with each other, whereby the first laminate is obtained. 30a and 2nd laminated body 30b are each produced, and the 1st laminated body 30a and the 2nd laminated body 30b are sliced, respectively, and the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b are produced.
For this reason, in the stage which produces the 1st laminated body 30a and the 2nd laminated body 30b, the orientation of the heat conductive filler 12 can be maintained inside the 1st sheet | seat 10 of a hardening state.
Thereby, the orientation of the heat conductive filler 12 in the 1st laminated body 30a and the 2nd laminated body 30b can be made favorable. As a result, the orientation of the heat conductive filler 12 in the first heat conductive sheet 40a and the second heat conductive sheet 40b obtained by slicing the first stacked body 30a and the second stacked body 30b in the stacking direction is also good. In addition, sufficient thermal conductivity is obtained in the thickness direction of the first heat conductive sheet 40a and the second heat conductive sheet 40b.
Therefore, sufficient thermal conductivity is obtained in the thickness direction of the heat conductive sheet 40 having the first heat conductive sheet 40a and the second heat conductive sheet 40b.

[Fifth Embodiment]
7A to 7C are schematic views showing a heat conductive sheet 40 according to the fifth embodiment, in which (a) is a perspective view, (b) is a front view, and (c). ) Is an enlarged cross-sectional view of part A of (b). The heat conductive sheet 40 according to the present embodiment is different from the heat conductive sheet 40 according to the fourth embodiment in the points described below, and otherwise the heat conductive sheet according to the fourth embodiment. 40 is configured in the same manner.

  In the case of this embodiment, unlike the fourth embodiment, adjacent quadrangular prism-shaped portions are directly bonded to each other. That is, the heat conductive sheet 40 according to the present embodiment does not have the adhesive layer (partition part) in the fourth embodiment.

  In the case of this embodiment, at least any one of the 1st heat conductive sheet 40a and the 2nd heat conductive sheet 40b has the square columnar part 41 and the square columnar part 42 alternately. The structure of the quadrangular columnar portion 41 is as described in the fourth embodiment.

  The quadrangular columnar portion 42 is the same as the quadrangular columnar portion 41. The square columnar part 42 is made of the organic resin 21 including the thermally conductive filler 12 and is formed in the same shape as the square columnar part 41. The organic resin 21 is the same as the organic resin 11.

  As shown in FIG. 7C, in each of the plurality of quadrangular prism-shaped portions 42, the size of the heat conductive filler 12 in the thickness direction of the heat conductive sheet 40 is the heat conductive filler in the surface direction of the heat conductive sheet 40. The thermally conductive filler 12 is oriented so as to be larger than 12 dimensions. That is, the thermal conductive filler 12 is oriented in the thickness direction of the thermal conductive sheet 40 in each of the plurality of square columnar portions 42.

The side surfaces of the quadrangular columnar portions 41 and 42 that are arranged along the surface direction of the heat conductive sheet 40 so that the plurality of quadrangular columnar portions 41 and the plurality of quadrangular columnar portions 42 are parallel to each other. They are directly bonded together to form a single sheet.
For example, a flat bonding interface 43 is formed at the boundary between the quadrangular columnar portion 41 and the quadrangular columnar portion 42.

  Next, an example of a method for manufacturing the heat conductive sheet 40 having the structure of the present embodiment will be described.

  Each of FIGS. 8A to 8H is a schematic diagram showing a molded product in each step in the method for manufacturing a heat conductive sheet according to the fifth embodiment.

  First, the 1st sheet | seat 10 is produced similarly to said 4th Embodiment (FIG. 8 (a)). That is, in the present embodiment, the organic resin 11 constituting the first sheet 10 is not in a semi-cured state but in a cured state. When an epoxy resin or polyimide is used as the organic resin 11, the first sheet 10 is obtained by forming the organic resin 11 into a thin film shape and then using the organic resin 11 as a C stage.

  On the other hand, the second sheet 20 (FIG. 8B) is the same as the first sheet 10 in the first embodiment. That is, the organic resin 21 constituting the second sheet 20 is not in a cured state but in a semi-cured state. When an epoxy resin or polyimide is used as the organic resin 21, the second sheet 20 is obtained by forming the organic resin 21 into a thin film shape and then setting the organic resin 21 to a B stage.

  As described above, a plurality of first sheets 10 (FIG. 8A) and a plurality of second sheets 20 (FIG. 8B) are produced.

  The thickness of the 1st sheet | seat 10 and the 2nd sheet | seat 20 can be 50 micrometers or more and 2 mm or less, respectively.

  Next, the 1st sheet | seat 10 and the 2nd sheet | seat 20 are laminated | stacked alternately (FIG.8 (c)). Here, the 1st sheet | seat 10 and the 2nd sheet | seat 20 are laminated | stacked alternately so that the uppermost layer and lowermost layer of the 1st laminated body 30a (FIG.8 (d)) may become the 1st sheet | seat 10, respectively.

  Next, the organic resin 21 which comprises the 2nd sheet | seat 20 is hardened by pressing the laminated | stacked 1st sheet | seat 10 and the 2nd sheet | seat 20 in those lamination directions (heat press molding). Thereby, adjacent 1st sheet | seats 10 are mutually integrated through the 2nd sheet | seat 20, and the 1st laminated body 30a of a rectangular parallelepiped shape is shape | molded (FIG.8 (d)). Here, the organic resin 21 constituting the second sheet 20 functions as an adhesive that bonds the first sheets 10 together.

  Next, the 1st laminated body 30a is cut | disconnected (sliced) in the lamination direction of the 1st sheet | seat 10 and the 2nd sheet | seat 20, and the 1st heat conductive sheet 40a is produced (FIG.8 (e)).

  Accordingly, the first heat conduction is performed such that the dimension of the heat conductive filler 12 in the thickness direction of the first heat conductive sheet 40a is larger than the dimension of the heat conductive filler 12 in the surface direction of the first heat conductive sheet 40a. The thermally conductive filler 12 in the sheet 40a is oriented. That is, the heat conductive filler 12 is oriented in the thickness direction. The quadrangular prism-shaped portion 41 is composed of a part of the first sheet 10, and the quadrangular prism-shaped portion 42 is composed of a part of the second sheet 20.

  On the other hand, by performing the same process (not shown) as the process of manufacturing the first stacked body 30a (FIGS. 8A to 8D), the second stacked body 30b similar to the first stacked body 30a (FIG. 8 (f)) is produced.

  Next, the second stacked body 30b is cut (sliced) in the stacking direction (vertical direction in FIG. 8 (f)) of the first sheet 10 and the second sheet 20 constituting the second stacked body 30b. The heat conductive sheet 40b is produced (FIG.8 (g)). Thus, the second heat conductive sheet 40b (FIG. 8 (g)) having the same configuration as the first heat conductive sheet 40a (FIG. 8 (e)) is obtained.

  Next, as shown in FIG. 8H, the first heat conductive sheet 40a and the second heat conductive sheet 40b are laminated and integrated with each other. Specifically, for example, the first heat conductive sheet 40a and the second heat conductive sheet 40b are integrated by bonding to each other through the adhesive layer 50. Thereby, the heat conductive sheet 40 is obtained. The adhesive layer 50 may be the same as that in the second embodiment. Moreover, the heat conductive sheet 40 may have the insulating layer 45 similar to 3rd Embodiment.

  According to the fifth embodiment as described above, in addition to the same effects as those of the first to third embodiments, the following effects can be obtained.

In the case of this embodiment, the 1st sheet | seat 10 containing the heat conductive filler 12 in the organic resin 11 of a hardening state and the 2nd sheet | seat 20 containing the heat conductive filler 12 in the organic resin 21 of a semi-hardened state are alternated. After being laminated, the organic resin 21 of the second sheet 20 is cured so that the adjacent first sheets 10 are integrated with each other via the second sheet 20, so that the first laminated body 30 a and the second laminated body are integrated. 30b is produced, and the first laminated body 30a and the second laminated body 30b are sliced to produce the first thermal conductive sheet 40a and the second thermal conductive sheet 40b.
For this reason, in the stage of producing the first laminate 30a and the second laminate 30b, not only can the orientation of the thermally conductive filler 12 be maintained inside the cured first sheet 10, but each first sheet 10 Moreover, it also serves as a function of maintaining the orientation of the heat conductive filler 12 inside the second sheet 20. That is, each first sheet 10 has an orientation of the heat conductive filler 12 due to the heat conductive filler 12 inside the second sheet 20 moving to the adjacent first sheet 10 side by the flow of the organic resin 21. By regulating the disturbance, the orientation of the heat conductive filler 12 in the second sheet 20 is maintained.
Thereby, the orientation of the heat conductive filler 12 in the 1st laminated body 30a and the 2nd laminated body 30b can be made favorable. As a result, the orientation of the heat conductive filler 12 in the first heat conductive sheet 40a and the second heat conductive sheet 40b obtained by slicing the first stacked body 30a and the second stacked body 30b in the stacking direction is also good. In addition, sufficient thermal conductivity is obtained in the thickness direction of the first heat conductive sheet 40a and the second heat conductive sheet 40b.
Therefore, sufficient thermal conductivity is obtained in the thickness direction of the heat conductive sheet 40 having the first heat conductive sheet 40a and the second heat conductive sheet 40b.

  In the above description, the example in which the heat conductive sheet 40 has a laminated structure of two layers of the heat conductive sheet of the first heat conductive sheet 40a and the second heat conductive sheet 40b has been described, but the heat conductive sheet 40 has three layers. The laminated structure of the above heat conductive sheets may be sufficient.

10 First sheet 11 Organic resin 12 Thermally conductive filler 15 Adhesive 20 Second sheet 21 Organic resin 30a First laminated body 30b Second laminated body 40 Thermal conductive sheet 40a First thermal conductive sheet 40b Second thermal conductive sheet 41 Square columnar portion 42 Square columnar portion 43 Bonding interface 45 Insulating layer 50 Adhesive layer 51 Thermally conductive filler

Claims (11)

A first heat conductive sheet comprising a scale-like, oval or rod-like first heat conductive filler in a thin film-shaped first cured organic resin, wherein the first heat conduction A first thermal conductive sheet in which the dimension of the first thermal conductive filler in the thickness direction of the sheet is larger than the dimension of the first thermal conductive filler in the surface direction of the first thermal conductive sheet;
A second heat conductive sheet comprising a second heat conductive filler having a scale shape, an oval shape or a rod shape in a second organic resin formed into a thin film and in a cured state, the second heat conduction A second heat conductive sheet in which the dimension of the second heat conductive filler in the thickness direction of the sheet is larger than the dimension of the second heat conductive filler in the surface direction of the second heat conductive sheet;
Have
A heat conductive sheet in which the first heat conductive sheet and the second heat conductive sheet are laminated and integrated with each other.   The heat conductive sheet according to claim 1, wherein an interface exists between the first heat conductive sheet and the second heat conductive sheet.   The heat conductive sheet according to claim 2, wherein the first heat conductive sheet and the second heat conductive sheet are integrated by being bonded to each other through an adhesive layer.   The heat conductive sheet according to claim 3, wherein the adhesive layer includes a third heat conductive filler.   The heat conductive sheet as described in any one of Claims 1 thru | or 4 further provided with the insulating layer formed in at least any one of the surface of the front and back of the said heat conductive sheet. The first thermally conductive filler is hexagonal boron nitride particles or graphite particles in which the hexagonal plane in the crystal is oriented in the plane direction of the scale, the long axis direction of the ellipse or the axial direction of the rod,
2. The second heat conductive filler is hexagonal boron nitride particles or graphite particles in which a hexagonal plane in the crystal is oriented in the plane direction of the scale, the long axis direction of the ellipse, or the axial direction of the rod. The heat conductive sheet as described in any one of thru | or 5. The first organic resin is an epoxy resin, polyimide or benzoxazine,
The heat conductive sheet according to any one of claims 1 to 6, wherein the second organic resin is an epoxy resin, polyimide, or benzoxazine. At least one of the first heat conductive sheet and the second heat conductive sheet is partitioned into a plurality of regions in the plane direction,
The heat conductive sheet according to any one of claims 1 to 7, wherein a partition portion that partitions adjacent regions is formed between adjacent regions among the plurality of regions. A first heat conductive sheet comprising a scale-like, oval or rod-like first heat conductive filler in a thin film-shaped first cured organic resin, wherein the first heat conduction Producing a first heat conductive sheet in which the dimension of the first heat conductive filler in the thickness direction of the sheet is larger than the dimension of the first heat conductive filler in the surface direction of the first heat conductive sheet;
A second heat conductive sheet comprising a second heat conductive filler having a scale shape, an oval shape or a rod shape in a second organic resin formed into a thin film and in a cured state, the second heat conduction Producing a second heat conductive sheet in which the dimension of the second heat conductive filler in the thickness direction of the sheet is larger than the dimension of the second heat conductive filler in the surface direction of the second heat conductive sheet;
Laminating and integrating the first heat conductive sheet and the second heat conductive sheet;
The manufacturing method of the heat conductive sheet which has this.   In the step of laminating and integrating the first heat conductive sheet and the second heat conductive sheet, the first heat conductive sheet and the second heat conductive sheet are bonded to each other through an adhesive layer. The manufacturing method of the heat conductive sheet of Claim 9 integrated by this.   The manufacturing method of the heat conductive sheet of Claim 10 using what contains a 3rd heat conductive filler as an adhesive agent which comprises the said contact bonding layer.

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