WO2014097561A1 - Heat dissipating sheet, heat dissipating apparatus, and method for manufacturing heat dissipating apparatus - Google Patents

Abstract

A heat dissipating sheet (20a) is disposed between a heat sink (13) of a semiconductor switching element (10), and a tube (30a). A porous base material (21a) of the heat dissipating sheet (20a) is compressed by means of the heat sink (13) and the tube (30a). A heat conductive material oozed out from the inside of the porous base material (21a) due to the compression of the porous base material (21a) is present between the porous base material (21a) and the heat sink (13) of the semiconductor switching element (10), and between the porous base material (21a) and the tube (30a). A gap between the heat dissipating sheet (20a) and the heat sink (13), and a gap between the heat dissipating sheet (20a) and the tube (30a) can be filled with the heat conductive material, and heat resistance between the heat sink (13) and the tube (30a) can be reduced.

Description

Heat dissipation sheet, heat dissipation device, and method of manufacturing the heat dissipation device Cross-reference of related applications

This disclosure is based on Japanese Patent Application No. 2012-279923 filed on December 21, 2012, the contents of which are incorporated herein by reference.

The present disclosure relates to a heat dissipation sheet, a heat dissipation device, and a method for manufacturing the heat dissipation device.

2. Description of the Related Art Conventionally, a semiconductor device is provided with a heat radiating sheet in which a sheet-like base material made of porous metal is filled with a heat transfer material, and this heat radiating sheet is disposed between a metal base of a semiconductor module and a heat sink. There is. (For example, refer to Patent Document 1).

In this case, the metal base and the heat sink are fastened in a state where the heat dissipation sheet is compressed by applying pressure to the heat dissipation sheet by the metal base and the heat sink. For this reason, the heat radiating sheet is plastically deformed according to the unevenness of the metal base and the heat sink. Thereby, the clearance between the metal base and the heat sink via the heat dissipation sheet can be reduced, and the thermal resistance can be lowered.

JP 2007-194442 A

In the semiconductor device of the above-mentioned patent document 1, in order to improve thermal conductivity, when a heat dissipation sheet having a reduced thickness is used, even if the heat dissipation sheet is plastically deformed by pressure as described above, the deformation amount Is insufficient, and the plastically deformed heat dissipation sheet does not have a shape along the irregularities of the metal base or heat sink.

For this reason, a gap is generated between the heat dissipation sheet and the metal base, and a gap is generated between the heat dissipation sheet and the heat sink. Accordingly, the thermal resistance between the heat dissipation sheet and the metal base is increased, and the thermal resistance between the heat dissipation sheet and the heat sink is increased.

On the other hand, if the pressure applied to the heat dissipation sheet by the metal base and heat sink is increased, the amount of deformation of the heat dissipation sheet increases, and the heat dissipation sheet deforms along the unevenness of the metal base and the heat sink, but the heat dissipation sheet is distorted. It will occur. In addition, if the heat dissipation sheet is greatly deformed by the pressure applied by the metal base and the heat sink, cracks may occur in the heat dissipation sheet. Such distortion and cracks generated in the heat radiating sheet cause a decrease in electrical insulation of the heat radiating sheet.

Therefore, in order to suppress the occurrence of distortion and cracks, it is conceivable to lower the elastic modulus of the heat dissipating sheet and greatly deform the heat dissipating sheet, but the material strength of the heat dissipating sheet decreases due to the decrease in the elastic modulus. For this reason, it is necessary to enlarge the thickness dimension of a thermal radiation sheet. Therefore, thermal conductivity cannot be improved.

In view of the above points, it is a first object of the present disclosure to provide a heat dissipating sheet that improves heat conductivity, and to provide a heat dissipating device that uses the heat dissipating sheet to improve heat dissipation. A second object is to provide a method for manufacturing a heat dissipation device that uses a heat dissipation sheet to enhance heat dissipation.

According to the first aspect of the present disclosure, the heat dissipation sheet is in the form of a sheet and has a porous substrate having a large number of holes, and has thermal conductivity, and is impregnated in the numerous holes of the porous substrate. A heat conductive material, and the heat conductive material can be oozed out of the porous substrate.

For example, if the heat dissipating sheet is disposed between the heating element and the cooling member, a heat conductive material is interposed between the heating element and the porous substrate, and heat conduction is performed between the cooling member and the porous substrate. Sexual substances can be interposed. For this reason, the thermal resistance between the heating element and the porous substrate and the thermal resistance between the cooling member and the porous substrate can be lowered. Therefore, heat transfer from the heating element to the cooling member can be improved. Thus, the heat-radiation sheet which improved thermal conductivity can be provided.

For example, the heat dissipation sheet is used in a heat dissipation device including a heat generating element that generates heat and a cooling member that cools the heat generating element. In this case, the heat radiating sheet is disposed between the heat generating body and the cooling member, and the heat conductive material that has oozed out from the porous base material constituting the heat radiating sheet is between the heat generating body and the porous base material and the cooling member. And between the porous substrate.

Therefore, it is possible to provide a heat dissipation device that uses a heat dissipation sheet to improve heat dissipation.

According to the second aspect of the present disclosure, in the heat dissipation sheet according to the first aspect, the porous base material has flexibility. Therefore, when the heat radiating sheet is disposed between the heating element and the cooling member, the porous substrate can be deformed according to the shape of the heating element or the cooling member. Therefore, the clearance gap which arises between a heat generating body and a cooling member via a heat radiating sheet can be made small. For this reason, the thermal resistance between the heating element and the porous substrate via the heat dissipation sheet can be further reduced.

According to the third aspect of the present disclosure, a method of manufacturing a heat dissipation device includes disposing the heat dissipation sheet between a heat generating element that generates heat and a cooling member that cools the heat generating element, And exuding a heat conductive substance from the porous base material to be formed to the heating element side and the cooling member side.

Therefore, it is possible to provide a method for manufacturing a heat dissipation device that uses a heat dissipation sheet to improve heat dissipation.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawing
It is a front view of the vehicle-mounted heat dissipation apparatus in 1st Embodiment of this indication. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is an enlarged view of a portion III in FIG. 2. It is a flowchart which shows the manufacturing process of the vehicle-mounted heat dissipation apparatus in the said 1st Embodiment. It is a flowchart which shows the manufacturing process of the vehicle-mounted heat dissipation apparatus in 2nd Embodiment of this indication.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
The on-vehicle heat dissipation device 1 in FIG. 1 is for dissipating heat from the semiconductor switching element 10. The semiconductor switching element 10 is a so-called power card, and is applied to an inverter circuit that outputs a three-phase AC voltage to a traveling motor.

Specifically, the in-vehicle heat dissipation device 1 includes heat dissipation sheets 20a and 20b as shown in FIG. The heat radiation sheet 20a is disposed between the heat sink 13 of the semiconductor switching element 10 and the tube 30a. The heat radiation sheet 20b is disposed between the heat sink 14 of the semiconductor switching element 10 and the tube 30b. 2 shows a state where the inside of the semiconductor switching element 10 is transmitted.

The heat radiation sheet 20a is obtained by impregnating a porous base material 21a formed in a sheet shape with a heat conductive substance. The heat dissipation sheet 20b is obtained by impregnating a porous base material 21b formed in a sheet shape with a heat conductive material. The porous base materials 21a and 21b are base materials each having a large number of holes.

The porous base materials 21a and 21b each have flexibility. Thus, each of the heat radiation sheets 20a and 20b is configured to have flexibility and freely change its shape.

The porous base materials 21a and 21b are formed so that two adjacent holes communicate with each other among a large number of holes. The porous base materials 21a and 21b are made of a resin material such as polytetrafluoroethylene having thermal conductivity and electrical insulation.

In the present embodiment, a heat radiation filler is added to the porous base materials 21a and 21b in order to improve thermal conductivity. The heat dissipation filler is a fine powder having thermal conductivity and electrical insulation. Specifically, materials such as boron nitride, alanina, and alumina nitride are used as the heat dissipating filler.

As the heat radiation sheets 20a and 20b of the present embodiment, those having a thickness dimension of 150 μm to 250 μm are used.

The heat conductive material is a fluid material having heat conductivity and electrical insulation. In addition, the heat conductive material has a viscosity and a high gas passage coefficient. In the present embodiment, for example, silicone is used as the heat conductive material. SE1880 (product number) manufactured by Toray Dow Corning Silicone Co., Ltd. is used as the silicone.

The size of the lower surface of the heat dissipation sheet 20a of the present embodiment is larger than the size of the surface 13a of the heat sink 13. The size of the upper surface of the heat dissipation sheet 20b is larger than the size of the back surface 14a of the heat sink 14.

As shown in FIG. 1, the tubes 30a and 30b constitute the cooler 50 together with the cooling water pipes 40a and 40b. The tubes 30a and 30b are metal pipes for circulating cooling water through the interiors 31a and 31b (see FIG. 2), respectively.

The cooling water pipes 40a and 40b are arranged so as to be orthogonal to the tubes 30a and 30b. The cooling water pipes 40a and 40b are arranged so as to sandwich the semiconductor switching element 10 in the flow direction of the cooling water in the tubes 30a and 30b (see arrow X).

The cooling water pipe 40a diverts the cooling water that has entered from the inlet 41a to the tubes 30a and 30b as indicated by the chain line arrow A in FIG. The cooling water pipe 40b collects the cooling water flowing out from the tubes 30a and 30b and discharges it from the outlet 41b as indicated by a chain line arrow B in FIG.

The cooling water pipe 40a includes a buckling portion 42a. The buckling portion 42a is disposed between the tubes 30a and 30b in the cooling water pipe 40a and is formed in a bellows shape. The buckling portion 42a is formed so as to be capable of contracting in the longitudinal direction (vertical direction in the drawing) of the cooling water pipe 40a by the bending thereof.

The cooling water pipe 40b includes a buckling portion 42b. The buckling portion 42b is disposed between the tubes 30a and 30b in the cooling water pipe 40b and is formed in a bellows shape. The buckling portion 42b is formed so as to be able to contract in the longitudinal direction (vertical direction in the figure) of the cooling water pipe 40b by the bending thereof.

The cooling water pipes 40a and 40b and the tubes 30a and 30b of the present embodiment are made of a metal material such as aluminum.

The semiconductor switching element 10 is formed in a thin plate shape, and as shown in FIG. 2, a semiconductor chip 11, a spacer 12, heat sinks 13 and 14, a plurality of terminals 15 (two terminals in FIG. 2). 15), and a resin mold portion 16.

The semiconductor chip 11 constitutes a switching element such as an IGBT. The semiconductor chip 11 is disposed between the heat sinks 13 and 14. The heat sinks 13 and 14 are each formed in a thin plate shape with copper. The heat sinks 13 and 14 each release heat generated from the semiconductor chip 11. The surface 13a of the heat sink 13 is exposed on the surface side of the resin mold portion 16 (upper side in FIG. 1).

The back surface 14 a of the heat sink 14 is exposed on the back surface side (the lower side in FIG. 1) of the resin mold portion 16. The spacer 12 is formed in a thin plate shape with copper. The spacer 12 is disposed between the semiconductor chip 11 and the heat sink 13. The plurality of terminals 15 are formed such that the respective leading ends protrude outward from the resin mold portion 16. The plurality of terminals 15 and the semiconductor chip 11 are connected by wires 15a. The resin mold portion 16 is made of an electrically insulating resin material, and is formed so as to cover the semiconductor chip 11, the spacer 12, the heat sinks 13 and 14, and the plurality of terminals 15.

The front surface 13a of the heat sink 13 and the back surface 14a of the heat sink 14 of this embodiment are processed and molded flat. Similarly, the upper surface and the lower surface of the tube 30a and the upper surface and the lower surface of the tube 30b are each processed and formed flat. The ten-point average roughness (Rz) of the surface 13a of the heat sink 13, the back surface 14a of the heat sink 14, the upper and lower surfaces of the tube 30a, and the upper and lower surfaces of the tube 30b is set to 6.3z to 50z.

The semiconductor chip 11 and the spacer 12 are connected by a solder layer 17a. The semiconductor chip 11 and the heat sink 14 are connected by a solder layer 17b. The spacer 12 and the heat sink 13 are connected by a solder layer 17c.

In the present embodiment, the size of the surface 13a (heat radiation surface) of the heat sink 13 is smaller than the size of the upper surface of the resin mold portion 16. The size of the back surface 14 a (heat radiating surface) of the heat sink 14 is smaller than the size of the bottom surface of the resin mold portion 16. The size of the lower surface of the heat dissipation sheet 20 a is smaller than the size of the upper surface of the resin mold portion 16. The size of the upper surface of the heat dissipation sheet 20 b is smaller than the size of the lower surface of the resin mold part 16.

Next, a method for manufacturing the on-vehicle heat dissipation device 1 of the present embodiment will be described with reference to FIG.

First, in the preparation step (step S100), the semiconductor switching element 10, the heat radiation sheets 20a and 20b, and the cooler 50 are prepared separately.
At this time, the cooler 50 is prepared with the buckling portions 42a and 42b extended.

In the next arrangement step (step S110), the heat radiation sheet 20a, the semiconductor switching element 10, and the heat radiation sheet 20b are arranged between the tubes 30a and 30b. Specifically, the heat dissipation sheet 20a is disposed between the heat sink 13 of the semiconductor switching element 10 and the tube 30a. Thereby, the heat radiating sheet 20a is arranged so as to cover the heat sink 13 from the upper side in FIG.

Furthermore, a heat radiation sheet 20b is disposed between the heat sink 14 of the semiconductor switching element 10 and the tube 30b. Thereby, the heat radiating sheet 20b is disposed so as to cover the heat sink 14 from the lower side in FIG.

Thereby, the semiconductor switching element 10 (power card) and the heat radiation sheets 20a and 20b are disposed between the tubes 30b and 30b.

In the next leaching process (step S120), the buckling portion 42a of the cooling water pipe 40a and the buckling portion 42b of the cooling water pipe 40b are contracted, respectively. This shortens the distance between the tubes 30a and 30b. For this reason, pressure is applied to the semiconductor switching element 10 and the heat radiation sheets 20a and 20b by the tubes 30a and 30b.

Therefore, the heat dissipation sheet 20a is compressed in the thickness direction by the heat sink 13 of the semiconductor switching element 10 and the tube 30a. In connection with this, a heat conductive substance oozes out from the porous base material 21a of the heat radiating sheet 20a to the heat sink 13 side and the tube 30a side. At this time, the heat conductive material that oozes out from the porous base material 21a of the heat dissipation sheet 20a to the heat sink 13 side can fill the gap between the porous base material 21a and the heat sink 13 by capillary action. In addition to this, the heat conductive material that oozes out from the porous base material 21a of the heat dissipation sheet 20a to the tube 30a side can fill the gap between the porous base material 21a and the tube 30a.

In addition to this, the heat radiation sheet 20b is compressed in the plate thickness direction by the heat sink 14 and the tube 30b. At this time, the heat conductive material oozes out from the porous base material 21b of the heat dissipation sheet 20b to the heat sink 14 side and the tube 30b side. For this reason, the heat conductive substance which oozes out from the porous base material 21b of the heat radiating sheet 20b to the heat sink 14 side fills a gap between the porous base material 21b of the heat radiating sheet 20b and the heat sink 14 by a capillary phenomenon. Can do. Furthermore, the thermally conductive material that has oozed out from the porous base material 21b of the heat radiating sheet 20b toward the tube 30b can fill the gap between the porous base material 21b of the heat radiating sheet 20b and the tube 30b.

In the next fixing step (step S130), in order to prevent the buckling portions 42a and 41b from extending, the tubes 30a and 30b are sandwiched and fixed between the tubes 30a and 30b by a fixing member. Thereby, between the tubes 30a and 30b, the heat radiating sheets 20a and 20b are maintained in a compressed state. Thus, the in-vehicle heat dissipation device 1 is completed.

Next, the operation of the in-vehicle heat dissipation device 1 of this embodiment will be described.

First, in the semiconductor switching element 10, when the semiconductor chip 11 performs switching operation, the semiconductor chip 11 generates heat as a heating element. At this time, heat generated from the semiconductor chip 11 is transmitted to the heat sink 13 through the solder layer 17a, the spacer 12, and the solder layer 17c. Along with this, heat is transferred from the heat sink 13 to the tube 30a through the heat dissipation sheet 20a. Therefore, in the tube 30a, the heat transmitted through the heat dissipation sheet 20a is exhausted to the cooling water. Thus, the tube 30a can cool the semiconductor switching element 10.

Further, heat generated from the semiconductor chip 11 is transmitted to the heat sink 14 through the solder layer 17b. At this time, heat is transmitted from the heat sink 14 to the tube 30b through the heat dissipation sheet 20b. Accordingly, in the tube 30b, the heat transmitted through the heat dissipation sheet 20b is exhausted to the cooling water. Thus, the tube 30b can cool the semiconductor switching element 10.

According to the present embodiment described above, the heat dissipation sheet 20a is disposed between the heat sink 13 and the tube 30a. The porous substrate 21a of the heat dissipation sheet 20a is compressed in the plate thickness direction by the heat sink 13 and the tube 30a. The heat conductive material that oozes out from the porous substrate 21a due to the compression of the porous substrate 21a is between the porous substrate 21a and the heat sink 14, and between the porous substrate 21a and the tube 30a. Intervene.

Here, concave portions are formed as processing marks on the surface 13a of the heat sink 13 and the lower surface of the tube 30a.

In contrast, in this embodiment, the processing trace can be filled with a heat conductive material. That is, the gap between the heat dissipation sheet 20a and the heat sink 13 and the gap between the heat dissipation sheet 20a and the tube 30a can be filled with the heat conductive material. For this reason, the thermal resistance between the heat sink 13 and the tube 30a via the heat radiation sheet 20a can be lowered. The processing mark is an uneven portion formed when the heat sink 13 or the tube 30a is formed by metal processing.

The heat dissipation sheet 20b is disposed between the heat sink 14 and the tube 30b. The porous substrate 21b of the heat dissipation sheet 20b is compressed in the thickness direction by the heat sink 14 and the tube 30b. The heat conductive material that oozes out from the porous base material 21b due to the compression of the porous base material 21b is between the porous base material 21b and the heat sink 14, and between the porous base material 21b and the tube 30b. Intervene.

Here, although the processing marks are formed on the surface 14a of the heat sink 14 and the upper surface of the tube 30b, the processing marks can be filled with the heat conductive material. That is, the gap between the heat dissipation sheet 20b and the heat sink 14 and the gap between the heat dissipation sheet 20b and the tube 30b can be filled with the heat conductive material. For this reason, the thermal resistance between the heat sink 14 and the tube 30b via the heat dissipation sheet 20b can be lowered.

As described above, the thermal resistance between the semiconductor switching element 10 and the tubes 30a and 30b can be lowered. Therefore, the heat dissipation of the semiconductor switching element 10 can be improved.

The heat dissipation sheet 20a of this embodiment has flexibility. For this reason, the heat dissipation sheet 20a can be deformed in conformity with the shapes of the heat sink 13 and the tube 30a. Therefore, for example, as shown in FIG. 3, when a curved recess 50 is formed in the tube 30 a and a recess 51 is formed as a processing mark of the heat sink 13, the recess 50 of the tube 30 a and The heat radiation sheet 20 a can be deformed in accordance with the recess 51 of the heat sink 13. Therefore, the gap between the heat sink 13 and the heat dissipation sheet 20a and the gap between the heat dissipation sheet 20a and the tube 30a can be reduced.

In FIG. 3, the heat radiation sheet 20 is deformed according to the shape of the heat sink 13 and the tube 30a, and the heat conductive material radiates heat in the recess 51 of the heat sink 13 or in the gap between the heat radiation sheet 20a and the tube 30a as indicated by the thick line arrows. The example which moves from the sheet | seat 20a is shown.

The heat radiating sheet 20b has flexibility like the heat radiating sheet 20a. For this reason, the heat dissipation sheet 20b is deformed along the shape of the heat sink 14 or the tube 30b. For this reason, the gap which arises between the heat sink 14 and the tube 30b can be made small like the case of the heat radiating sheet 20a.

The heat conductive material constituting the heat radiation sheets 20a and 20b of the present embodiment has a viscosity in advance as described above. For this reason, it can prevent that a heat conductive substance is extruded from between the thermal radiation sheet | seat 20a and the heat sink 13 by a cooling-heat cycle or a capillary phenomenon. That is, the heat conductive material can be held between the heat dissipation sheet 20a and the heat sink 13 by the viscosity of the heat conductive material. For the same reason, the heat conductive material is held between the heat radiation sheet 20a and the tube 30a. Thermally conductive materials are also held between the heat dissipation sheet 20b and the heat sink 14 and between the heat dissipation sheet 20b and the tube 30b. Therefore, the thermal resistance between the semiconductor switching element 10 and the tubes 30a and 30b can be maintained in a low state.

As described above, the porous base materials 21a and 21b of the heat radiation sheets 20a and 20b of the present embodiment have a structure in which two adjacent holes are in communication with each other. For this reason, the heat radiating sheets 20a and 20b can pass the gas through a plurality of holes communicated among a large number of holes. In addition to this, the thermally conductive material has a high gas passage coefficient. Therefore, even if gas is generated from the heat dissipation sheets 20a and 20b, the gas can be discharged to the outside through the porous base materials 21a and 21b and the heat conductive material.

The porous base materials 21a and 21b and the heat conductive material of the heat radiation sheets 20a and 20b of the present embodiment have electrical insulation. For this reason, the heat radiation sheets 20a and 20b have electrical insulation. Therefore, electrical insulation between the semiconductor chip 11 and the tube 30a can be ensured by the heat dissipation sheet 20a. Furthermore, the electrical insulation between the semiconductor chip 11 and the tube 30b can be ensured by the heat dissipation sheet 20b. Therefore, it is not necessary to provide an electrical insulating member other than the heat radiation sheets 20a and 20b. For this reason, the increase in the number of parts can be suppressed.

In addition, when cracks are generated in the porous base materials 21a and 21b, or when the heat radiation filler is peeled off from the porous base materials 21a and 21b and voids are formed as peeling marks, the cracks and peeling marks are the starting points of dielectric breakdown. Can be.

On the other hand, in this embodiment, the thermally conductive material that has exuded from the porous base materials 21a and 21b can fill the cracks generated in the porous base materials 21a and 21b and the peeling trace of the heat radiation filler. For this reason, even if it is a case where the defect of the porous base materials 21a and 21b, such as a crack and a peeling trace, was not discovered by the inspection of a manufacturing process, the said heat conductive substance can repair the said defect.

In the heat radiating sheets 20a and 20b of the present embodiment, the heat conductive material is not cured, and the heat conductive material maintains viscosity. For this reason, for example, even if the heat radiating sheet 20a is arranged on the surface 13a of the heat sink 13 (or the lower surface of the tube 30a), the heat radiating sheet 20a can be peeled off from the heat sink 13 on which the heat radiating sheet 20a is arranged. For this reason, the heat radiating sheet 20 a can be disposed on the heat sink 13 again. That is, even if the heat dissipation sheet 20a is once attached to the heat sink 13 or the tube 30a, the heat dissipation sheet 20a can be attached again. The heat radiation sheet 20b has the same effect as the heat radiation sheet 20a.
(Second Embodiment)
In the first embodiment, the example using the heat radiation sheet 20a in which the porous base material 21a is impregnated with the heat conductive material having viscosity in advance has been described. A heat radiating sheet 20a formed by impregnating the porous base material 21a with a low thermal conductive material is prepared, and when the heat radiating sheet 20a is assembled between the heat sink 13 and the tube 30a, the heat radiating sheet 20a is thermally conductive. An example of attaching a cross-linking agent that increases the viscosity of a substance will be described.

In the present embodiment, a heat radiating sheet 20a is prepared by impregnating the porous base material 21a with a heat conductive material having low viscosity. Similarly, a heat radiating sheet 20b prepared by impregnating the porous base material 21b with a heat conductive material having low viscosity is prepared.

For example, CY52-276A & B (product number) manufactured by Toray Dow Corning Silicone Co., Ltd. is used as the heat conductive material impregnated in the porous base materials 21a and 21b and the crosslinking agent (additive).

Here, CY52-276A & B is composed of a main agent and an auxiliary agent that causes a cross-linking reaction to the main agent. A main agent can be used as a heat conductive substance. The main agent contains a catalyst that accelerates the reaction rate of the crosslinking reaction. An auxiliary agent can be used as a crosslinking agent.

Next, the manufacturing process of the vehicle-mounted heat dissipation device of this embodiment will be described. FIG. 5 is a flowchart showing a manufacturing process of the in-vehicle heat dissipation device of the present embodiment.
FIG. 5 includes a preparation step (step S100A) in place of the preparation step (step S100) and a cross-linking agent adhesion / placement step (step S110A) in place of the arrangement step (step S110) in the flowchart of FIG. .

First, in the preparation step (step S100A), the semiconductor switching element 10, the cooler 50, and the heat radiation sheets 20a and 20b impregnated with the heat conductive material having low viscosity are separately prepared.

Next, in the cross-linking agent adhesion / arrangement step (step S110A), the semiconductor switching element 10 is disposed between the tubes 30a and 30b. At this time, a cross-linking agent (additive) is attached to the surface 13a of the heat sink 13, the lower surface of the heat radiating sheet 20a is disposed on the surface 13a with the cross-linking agent, and the upper surface of the heat radiating sheet 20a is disposed on the lower surface of the tube 30a. . Thereby, a crosslinking agent adheres to the porous base material 21a of the heat dissipation sheet 20a. For this reason, the crosslinking reaction by the crosslinking agent starts in the heat conductive material impregnated in the porous substrate 21a. Thereby, hardening of a heat conductive substance is started.

Further, when the semiconductor switching element 10 is disposed between the tubes 30a and 30b, a crosslinking agent is attached to the back surface 14a of the heat sink 14, and the upper surface of the heat radiation sheet 20b is disposed on the back surface 14a with the crosslinking agent. The lower surface of the heat radiating sheet 20b is disposed on the upper surface. Thereby, a crosslinking agent adheres to the porous base material 21a of the heat dissipation sheet 20a. For this reason, the crosslinking reaction by the crosslinking agent starts in the heat conductive material impregnated in the porous substrate 21b. Thereby, hardening of a heat conductive substance is started.

As described above, when the heat radiation sheets 20a and 20b are disposed between the tubes 30a and 30b, curing of the heat conductive material impregnated in the porous base materials 21a and 21b is started.

Thereafter, in the next seepage process (step S120), the buckling part 42a of the cooling water pipe 40a and the buckling part 42b of the cooling water pipe 40b are contracted, respectively, so that the semiconductor switching element 10 and the heat radiation sheets 20a, 20b are contracted. Apply pressure to.

Therefore, as in the first embodiment, the porous base material 21a of the heat dissipation sheet 20a is compressed. Along with this, the heat conductive material that has oozed out of the porous base material 21 a fills the gap between the porous base material 21 a and the heat sink 13. In addition to this, the thermally conductive material that has oozed out of the porous substrate 21a can fill the gap between the porous substrate 21a and the tube 30a.

Also, the porous substrate 21b of the heat dissipation sheet 20b is compressed. For this reason, the heat conductive substance which oozes out from the porous base material 21 b can fill a gap between the porous base material 21 b and the heat sink 14. Furthermore, the thermally conductive material that has oozed out of the porous substrate 21b can fill the gap between the porous substrate 21b and the tube 30b.

In the next fixing step (step S130), the space between the tubes 30a and 30b is fixed by a fixing member. This completes the assembly of the in-vehicle heat dissipation device 1. Then, in order to harden a heat conductive substance and to raise the viscosity of a heat conductive substance, the vehicle-mounted heat radiator 1 will be made to stand by for a predetermined period. For example, when the in-vehicle heat radiating device 1 is made to stand by in an environment at a room temperature of 25 degrees, it is necessary to place the in-vehicle heat radiating device 1 in the room for about 20 hours.

According to this embodiment described above, when the heat dissipation sheet 20a is assembled between the heat sink 13 and the tube 30a, and when the heat dissipation sheet 20b is assembled between the heat sink 14 and the tube 30b, the heat dissipation sheets 20a and 20b A cross-linking agent (ie, an additive) that increases the viscosity of the thermally conductive material is deposited. In connection with this, hardening of a heat conductive substance can be started. Thereafter, by waiting the in-vehicle heat dissipation device 1 that has been assembled for a necessary time, in the in-vehicle heat dissipation device 1, the viscosity of the heat conductive material can be increased in a state of being disposed between the tubes 30a and 30b. . Therefore, similarly to the first embodiment, a heat conductive material can be held between the heat sink 13 and the tube 30a via the heat dissipation sheet 20a. A thermally conductive material can be held between the heat sink 14 and the tube 30b via the heat dissipation sheet 20b.

(Other embodiments)
In the first and second embodiments, the example in which the size of the lower surface of the heat radiating sheet 20a is made smaller than the size of the upper surface of the resin mold portion 16 has been described. The size may be larger than the size of the upper surface of the mold part 16.

Similarly, the size of the upper surface of the heat dissipation sheet 20b may be larger than the size of the lower surface of the resin mold portion 16.

In the second embodiment, when the semiconductor switching element 10 is disposed between the tubes 30a and 30b, a cross-linking agent is attached to the surface 13a of the heat sink 13, and the lower surface of the heat dissipation sheet 20a is attached to the surface 13a with the cross-linking agent. However, instead of this, the following (1) and (2) may be used.

(1) When the semiconductor switching element 10 is disposed between the tubes 30a and 30b, a cross-linking agent is attached to the lower surface of the tube 30a, and the upper surface of the heat dissipation sheet 20a is disposed on a portion of the lower surface of the tube 30a with the cross-linking agent. Then, the lower surface of the heat dissipation sheet 20 a is disposed on the surface 13 a of the heat sink 13. Thereby, a crosslinking agent is made to adhere to the porous base material 21a of the heat-radiation sheet 20a.

(2) When the semiconductor switching element 10 is disposed between the tubes 30a and 30b, a crosslinking agent is directly applied to the heat dissipation sheet 20a.

Similarly, the following (3) and (4) may be used in order to adhere the crosslinking agent to the porous base material 21b of the heat radiation sheet 20b.

(3) When the semiconductor switching element 10 is arranged between the tubes 30a and 30b, a crosslinking agent is attached to the upper surface of the tube 30b, and the lower surface of the heat dissipation sheet 20b is arranged on the portion of the upper surface of the tube 30b with the crosslinking agent. Then, the upper surface of the heat dissipation sheet 20 b is disposed on the lower surface of the heat sink 14. Thereby, you may make a crosslinking agent adhere to the porous base material 21b of the thermal radiation sheet 20b.

(4) When the semiconductor switching element 10 is disposed between the tubes 30a and 30b, a crosslinking agent is directly applied to the heat dissipation sheet 20b.

In the first and second embodiments, the example in which the vehicle-mounted heat dissipation device 1 is used as the heat dissipation device of the present disclosure has been described, but instead of this, the heat dissipation device of the present disclosure other than the vehicle-mounted heat dissipation device 1 You may use for this heat dissipation device.

In the first and second embodiments, the heat sink sheets 20a and 20b are formed by the tubes 30a and 30b by contracting the buckling portions 42a and 41b of the cooling water pipes 40a and 40b to shorten the space between the tubes 30a and 30b. However, instead of this, the heat radiation sheets 20a and 20b may be compressed by fixing the tube 30a and 30b with a fastening member such as a screw.

In the first and second embodiments, the example in which the semiconductor switching element 10 is used as the heating element has been described. However, instead of this, a member other than the semiconductor switching element 10 may be used as the heating element.

In the first embodiment, the example in which the space between the porous base material 21a and the heat sink 13 (or the tube 30a) is filled with a heat conductive material having viscosity has been described. The space between the porous substrate 21a and the heat sink 13 (or the tube 30a) may be filled with the heat conductive material. That is, the space between the porous substrate 21a and the heat sink 13 (or the tube 30a) may be filled with a liquid heat conductive material having low viscosity.

Similarly, the space between the porous substrate 21b and the heat sink 14 (or the tube 30b) may be filled with a liquid heat conductive material having low viscosity.

In the first and second embodiments, when the heat dissipating sheet 20a is disposed between the heat sink 13 and the tube 30a, the heat dissipating sheet 20a is added with an additive that causes a reaction to give adhesiveness to the heat conductive material. May be attached. As a result, the thermally conductive material becomes adhesive due to the reaction of the additive. This thermally conductive material having adhesiveness adheres between the heat radiation sheet 20a and the heat sink 13, and also adheres between the heat radiation sheet 20a and the tube 30a.

Similarly, when the heat radiation sheet 20b is disposed between the heat sink 14 and the tube 30b, an additive that causes a reaction to give adhesiveness to the heat conductive material may be attached to the heat radiation sheet 20b. As a result, the thermally conductive material having adhesiveness adheres between the heat dissipation sheet 20b and the heat sink 14, and also adheres between the heat dissipation sheet 20b and the tube 30b.

In the second embodiment, for example, CY52-276A & B (product number) manufactured by Toray Dow Corning Silicone Co., Ltd. is used as the heat conductive material impregnated in the porous base materials 21a and 21b and the crosslinking agent. However, instead of this, a main agent (thermally conductive substance) and a cross-linking agent (additive) may be generated using a product manufactured by Gelesr (Gerest), USA.

Specifically, DMS-T21 (100cSr.silicone fluid), SIS6964.0-S45 (silica powder), SN3260 (DBTL tin catalyst) mixed at a mixing ratio of 50%, 45%, 5% Thermally conductive material).

Also, a mixture obtained by mixing DMS-S45 (silnolＳfluid), SIS6964.0-S45 (silica 、 powder), PSI-021 (erthlsilicare) at a mixing ratio of 70%, 28%, and 2% is used as a crosslinking agent.

DMS-T21, SIS6964.0-S45, SN3260, DMS-S45, SIS6964.0-S45, and PSI-021 indicate the product numbers of Gelres.

In the said 1st, 2nd embodiment, although the example using the thing to which the thermal radiation filler was added was demonstrated as the porous base materials 21a and 21b, it replaces with this, and as a heat conductive substance, it is beforehand thermal radiation filler. Those added with may also be used. The heat radiation filler added to the heat conductive material is a fine powder having heat conductivity and electrical insulation. Specifically, materials such as boron nitride, alanina, and alumina nitride are used as the heat dissipating filler.

Alternatively, as the porous base materials 21a and 21b, a material to which a heat dissipating filler has been added in advance may be used, and a material to which a heat dissipating filler has been added in advance may be used as a thermally conductive substance.

In the first and second embodiments, the heat dissipation sheet 20a is disposed on the front surface side (upper side in FIG. 1) of the semiconductor switching element 10, and the heat dissipation sheet is disposed on the rear surface side (lower side in FIG. 1) of the semiconductor switching element 10. Although the example which has arrange | positioned 20b was demonstrated, you may arrange | position a thermal radiation sheet only to one side among the surface side and the back surface side of the semiconductor switching element 10 not only in this.

For example, when the semiconductor switching element 10 using the heat sinks 13 and 14 in which the heat sink 13 is abolished and only the heat sink 14 is exposed on the lower surface side of the resin mold portion 16 is used, The heat radiation sheet 20b is disposed only on the side. Then, the semiconductor switching element 10 and the tube 30b are fixed by fastening screws or the like in a state where the heat dissipation sheet 20b is interposed between the semiconductor switching element 10 and the tube 30b. Thereby, the porous base material 21b of the heat radiating sheet 20b is compressed by the heat sink 14 and the tube 30b, and the heat conductive material can be oozed out. The exuding heat conductive material can fill the gap between the heat radiation sheet 20b and the heat sink 14 and the gap between the heat radiation sheet 20b and the tube 30b with the heat conductive material.

In the first and second embodiments, the example in which the tubes 30a and 30b are used as the cooling members has been described. However, instead of this, the radiation fins that promote the heat radiation of the tubes 30a and 30b may be used as the cooling members. Good.

In the first and second embodiments described above, the heat conductive material oozes from the porous base material 21a to the heat sink 13 side and the tube 30a side by compression of the porous base material 21a of the heat dissipation sheet 20a. As described above, instead of this, the heat conductive material may ooze out from the porous base material 21a to the heat sink 13 side and the tube 30a side by its own weight.

Note that the present disclosure is not limited to the above-described embodiment, and can be appropriately changed within the scope described in the claims. Further, the above embodiments are not irrelevant to each other, and can be combined as appropriate unless the combination is clearly impossible. Further, in each of the above embodiments, when referring to the shape, positional relationship, etc. of the component, etc., the shape, unless otherwise specified and in principle limited to a specific shape, positional relationship, etc. It is not limited to the positional relationship or the like.

Claims (24)

1. A sheet-like porous substrate (21a, 21b) having a large number of pores;
   A thermal conductive material having thermal conductivity and impregnated in a number of pores of the porous substrate;
   A heat dissipating sheet configured to allow the heat conductive material to ooze out from the porous base material.
2. The heat dissipation sheet according to claim 1, wherein the porous substrate has flexibility.
3. The heat-dissipating sheet according to claim 1 or 2, wherein the thermally conductive substance has electrical insulation.
4. The heat dissipation sheet according to any one of claims 1 to 3, wherein the porous base material is formed of a resin material.
5. The heat-dissipating sheet according to any one of claims 1 to 4, wherein the heat-conducting substance is added with a filler having heat-conductivity.
6. The heat-dissipating sheet according to any one of claims 1 to 5, wherein the porous substrate is added with a filler having thermal conductivity.
7. The heat radiating sheet according to any one of claims 1 to 6, wherein the porous base material has a structure in which adjacent holes among the plurality of holes communicate with each other and allow gas to permeate through the communicated holes.
8. The heat-dissipating sheet according to any one of claims 1 to 7, wherein the thermally conductive material is a gas-permeable material that allows gas to pass therethrough.
9. The heat dissipation sheet according to any one of claims 1 to 8, wherein the porous base material is configured to be able to exude the heat conductive material by being compressed.
10. The heat-radiating sheet according to any one of claims 1 to 9, wherein the thermally conductive substance has a viscosity in advance.
11. Cooling members (30a, 30b) for cooling the heating element (10) that generates heat;
    A heat dissipation sheet (20a, 20b) according to any one of claims 1 to 9,
    The heat dissipating sheet is disposed between the heating element and the cooling member,
    A heat dissipating device in which a heat conductive material oozing out from a porous base material constituting the heat radiating sheet is interposed between the heating element and the porous base material and between the cooling member and the porous base material. .
12. The heat dissipating device according to claim 11, wherein the porous base material is impregnated with a viscous heat conductive material in advance.
13. The viscosity of the thermally conductive material is increased by an additive attached to the heat dissipation sheet when the heat dissipation sheet is disposed between the heating element and the cooling member. Heat dissipation device.
14. The heat dissipation device according to claim 13, wherein the additive is directly attached to the heat dissipation sheet when the heat dissipation sheet is disposed between the heating element and the cooling member.
15. When arranging the heat dissipation sheet between the heating element and the cooling member, the additive is attached to one member of the heating element and the cooling member, and the additive is attached to the one member. The heat dissipating device according to claim 13, wherein the additive is attached to the heat dissipating sheet by disposing the heat dissipating sheet in a portion.
16. The cooling member has first and second cooling members,
    The heat dissipating sheet has first and second heat dissipating sheets,
    The heating element is disposed between the first and second cooling members;
    The first heat dissipation sheet is disposed between the heating element and the first cooling member,
    The heat dissipation device according to any one of claims 11 to 15, wherein the second heat dissipation sheet is disposed between the heating element and the second cooling member.
17. The first porous substrate constituting the first heat radiating sheet and the second porous substrate constituting the second heat radiating sheet are compressed by the first and second cooling members, respectively. And
    The heat conductive material that oozes out of the first porous substrate as the first porous substrate is compressed is between the heating element and the first porous substrate and between the first porous substrate and the first porous substrate. Interposed between the cooling member and the first porous substrate,
    The heat conductive material that oozes out from the second porous base material as the second porous base material is compressed is between the heating element and the second porous base material and between the second porous base material and the second porous base material. The heat dissipating device according to claim 16, which is interposed between a cooling member and the second porous substrate.
18. The heat dissipating sheet (20a, 20b) according to any one of claims 1 to 9 is provided between a heat generating element (10) that generates heat and a cooling member (30a, 30b) that cools the heat generating element. Arranging (S110);
    A heat-radiating device manufacturing method comprising: causing a heat conductive substance to ooze out from a porous base material constituting the heat-dissipating sheet to the heating element side and the cooling member side (S120).
19. The method for manufacturing a heat dissipation device according to claim 18, wherein the porous base material is impregnated with the thermally conductive substance having viscosity in advance.
20. The heat dissipating device according to claim 19, wherein when disposing the heat dissipating sheet between the heating element and the cooling member, the heat dissipating sheet is provided with an additive for increasing the viscosity of the heat conductive material. Manufacturing method.
21. 21. The method of manufacturing a heat radiating device according to claim 20, wherein, when the heat radiating sheet is disposed between the heating element and the cooling member, the additive is directly attached to the heat radiating sheet.
22. In the arrangement, when the heat dissipating sheet is arranged between the heating element and the cooling member, the additive is added to one member of the heating element and the cooling member. The manufacturing method of the heat radiating device according to claim 20, wherein the heat-dissipating sheet is disposed in a portion with the additive to attach the additive to the heat-dissipating sheet.
23. The cooling member has first and second cooling members,
    The heat dissipating sheet has first and second heat dissipating sheets,
    In the arrangement, the first heat radiating sheet is arranged between the first cooling member and the heating element, and is arranged on the side opposite to the first cooling member with respect to the heating element. The method for manufacturing a heat dissipation device according to any one of claims 18 to 22, wherein the second heat dissipation sheet is disposed between the second cooling member and the heating element.
24. In the exudation, the first porous substrate constituting the first heat radiation sheet and the second porous substrate constituting the second heat radiation sheet by the first and second cooling members. 24. The method for manufacturing a heat radiating device according to claim 23, wherein the thermal conductive material is oozed out of the first and second porous substrates by compressing each of the first and second porous substrates.

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