JP2023134890A - Method for manufacturing thermally conductive structure and method for manufacturing heat radiation structure - Google Patents

Abstract

To provide a method for manufacturing a thermally conductive structure that can achieve both formation of a desired film thickness and flattening.SOLUTION: A method for manufacturing a thermally conductive structure includes: a resin frame formation step of applying a resin composition containing resin and foaming agent to an adherend 11 to form a resin frame 12; a liquid film formation step of applying a thermally conductive composition 13a containing a thermally conductive material to the inside of the resin frame 12 by an ink jet method to form a liquid film 13b; a heating step of heating the liquid film 13b and the resin frame 12 to solidify the liquid film 13b and foam the resin frame 12; a removal step of removing the resin frame 12 foamed by heating from the adherend 11; and a curing step of, after removing the resin frame 12, heating to cure the solidified liquid film 13b.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method of manufacturing a thermally conductive structure and a method of manufacturing a heat dissipation structure.

BACKGROUND ART In recent years, as electronic circuit boards have become more highly integrated and faster, deterioration in circuit performance due to heating elements such as IC chips has become a problem, and higher performance heat dissipation technology that suppresses temperature increases is required. As such a heat dissipation technique, a method is adopted in which a heat dissipation member such as a heat sink is provided on a heat generating body such as an IC chip. For example, a thermally conductive structure (thermal interface material) disposed between the heat generating element 3 and the heat dissipating member 5 is used to increase the thermal conductivity in the thermally conductive adhesive part (TIM: Thermal interface material) of the heat dissipating structure shown in FIG. As the conductive sheet) 1, an alkali resin heat dissipating foam sheet has been proposed, for example, which is formed by mixing air bubbles into an acrylic resin containing a thermally conductive substance to form a foam (for example, see Patent Document 1).

On the other hand, the inkjet method is a method that can apply a desired material to a desired site on demand, and in recent years has been expected to be used in fields other than image formation. In the inkjet method, since the viscosity of the applied liquid composition is low, the droplets tend to spread and level after landing on a flat adherend. It's advantageous.

However, in the inkjet method, it is necessary to lower the solid content concentration of the thermally conductive composition for ejection stability, and it is difficult to form a film with a film thickness of 10 μm or more than 10 μm. In addition, when forming a film of a thermally conductive composition for the purpose of heat dissipation on the surface of an IC package, the film thickness is determined when (1) the IC package surface has irregularities of several μm, or (2) the coating film interface. In order to alleviate thermal stress, the film thickness is preferably 10 μm to 100 μm. If the film thickness is too thick, it will be difficult to make the device thin, and if the film thickness is too thin, it will be difficult to fill in the irregularities on the surface of the IC package and to alleviate thermal stress.

Therefore, in order to solve the above-mentioned problem, a technique has been proposed in which, for example, an air heater is used to heat the coated portion of the substrate on which the liquid composition is coated to increase the film thickness (see, for example, Patent Document 2). However, excessive heating of the liquid composition immediately after coating, as proposed in this proposal, is one of the factors that impairs the leveling of the coating film and the highly accurate controllability of film thickness, which are characteristics of the inkjet method. becomes.

Furthermore, as in Patent Document 1, when TIM is manufactured by an inkjet method using a thermally conductive composition containing metal particles, the thermally conductive composition containing metal particles is generally expensive and the resin is bulky. It is preferable not only to increase the cost, but also to use a highly adhesive resin from the viewpoint of improving mechanical strength. However, in the inkjet method, it is difficult to obtain the desired film thickness because the droplets spread and spread. is difficult.
Therefore, when manufacturing TIMs by the inkjet method, it is extremely difficult to achieve both desired film thickness and planarization.

An object of the present invention is to provide a method for manufacturing a thermally conductive structure that can achieve both desired film thickness and planarization.

The method for manufacturing a thermally conductive structure of the present invention as a means for solving the above problems includes a resin frame forming step of forming a resin frame by applying a resin composition containing a resin and a foaming agent, and a step of forming a resin frame by applying a resin composition containing a resin and a foaming agent. A liquid film forming step of forming a liquid film by applying a thermally conductive composition containing a thermally conductive substance to the inside of the frame by an inkjet method, and heating the liquid film and the resin frame to form the liquid film. The method includes a heating step of solidifying and foaming the resin frame, and a removing step of removing the resin frame.

According to the present invention, it is possible to provide a method for manufacturing a thermally conductive structure that can achieve both desired film thickness formation and planarization.

FIG. 1 is a schematic cross-sectional view showing an example of a heat dissipation structure. FIG. 2 is a diagram showing an example of the orientation state of carbon fibers as a thermally conductive substance. FIG. 3 is a process diagram showing an example of the method for manufacturing the thermally conductive structure according to the first embodiment. FIG. 4 is a process diagram showing an example of a method for manufacturing a thermally conductive structure according to the second embodiment.

(Method for manufacturing thermally conductive structure)
The method for manufacturing a thermally conductive structure of the present invention includes a resin frame forming step, a liquid film forming step, a heating step, and a removing step, preferably including a curing step, and further includes other steps as necessary. Including process.

In the present invention, there is a resin frame forming step in which a resin frame is formed by applying a resin composition containing a resin and a foaming agent, and a thermally conductive composition containing a thermally conductive substance is applied inside the resin frame. a liquid film forming step of applying with an inkjet method to form a liquid film; a heating step of heating the liquid film and the resin frame to solidify the liquid film and foam the resin frame; and removing the resin frame. By including the removal step of removing the liquid, it is possible to prevent the liquid thermally conductive composition from spreading by the resin frame, and the liquid film is solidified by heating, and the resin frame foams and can be easily removed. It is possible to efficiently manufacture a flat thermally conductive structure with a film thickness of .

<Resin frame forming process>
The resin frame forming step is a step of forming a resin frame by applying a resin composition containing a resin and a foaming agent.
The resin composition contains a resin and a foaming agent, preferably a solvent, and further contains other components as necessary.

-Foaming agent-
The foaming agent is not particularly limited and can be appropriately selected depending on the purpose, for example, ammonium carbonate (foaming temperature: 58°C), 2,2'-azobisisobutyronitrile (foaming temperature: 85°C). °C to 90 °C), azohexahydrobenzonitrile (foaming temperature: 103 °C to 104 °C), diazoaminobenzene (foaming temperature: 90 °C to 100 °C), benzene sulfohydrazide (foaming temperature: 90 °C to 100 °C), p-Toluenesulfonylhydrazide (foaming temperature: 110°C), diphenylsulfone-3,3'-disulfohydrazide (foaming temperature: 148°C), diphenyl oxide-4,4'-disulfohydrazide (foaming temperature: 150°C) ), N,N'-dinitroso-N,N'-dimethylterephthalamide (foaming temperature: 105°C), and terephthalazide (foaming temperature: 90°C to 110°C). These may be used alone or in combination of two or more. Note that the foaming temperature is synonymous with the decomposition temperature.
The foaming temperature (decomposition temperature) of the foaming agent is preferably 200°C or lower, more preferably 150°C or lower, and even more preferably 50°C or higher and 130°C or lower.
If a foaming agent with a foaming temperature exceeds 200°C is heated at a temperature exceeding 200°C to foam the foaming agent, the thermally conductive composition will be fully cured, making it impossible to bond the heat dissipation member in the subsequent process, resulting in poor heat dissipation. It becomes necessary to use a conductive adhesive when bonding the members.

-resin-
The resin is not particularly limited and can be selected as appropriate depending on the purpose; for example, polypropylene resin, silicone resin, fluororesin, polyacetal resin, ethylene propylene diene rubber (EPDM), polyvinyl chloride resin, polyamide resin. , polyethylene resin, polycarbonate resin, polyester resin, polystyrene resin, etc. These may be used alone or in combination of two or more.

-solvent-
The solvent is not particularly limited and can be appropriately selected depending on the purpose, such as xylene, toluene, butyl acetate, N-methyl-2-pyrrolidone, 2-pyrrolidone, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, Examples include N,N-dimethylacetamide, 2-n-butoxymethanol, and 2-dimethylethanol. These may be used alone or in combination of two or more.
Among the above-mentioned solvents, those having a boiling point of 80°C to 150°C are preferred. If the boiling point of the solvent is too high, the resin composition will easily wet and spread, and fine patterning may become difficult in plateless printing such as an inkjet method or a dispenser method. On the other hand, if the boiling point of the solvent is too low, the resin composition may dry too quickly, making it difficult to perform a stable process.

-Other ingredients-
The other components are not particularly limited and can be selected as appropriate depending on the purpose, such as thixotropic agents, dispersants, curing accelerators, retarders, slight tackifiers, plasticizers, and flame retardants. , antioxidants, stabilizers, colorants, etc.

By applying the resin composition onto an adherend and drying it, a resin frame can be formed on the adherend.
The method for applying the resin composition is not particularly limited and can be appropriately selected depending on the purpose, for example, an inkjet method, a dispenser method, a screen printing method, a dip coating method, a spray coating method, a spin coating method, Bar coating method, slot die coating method, doctor blade coating method, curtain coating method, offset printing method, gravure printing method, flexographic printing method, letterpress printing method, screen printing method, electrophotographic printing method using liquid development method, etc. . Among these, the inkjet method and the dispenser method are preferred because patterning is easy, and the inkjet method is more preferred because the position at which droplets are ejected can be controlled.

-Adherend-
The material, shape, size, structure, etc. of the adherend are not particularly limited and can be appropriately selected depending on the purpose.
The material of the adherend is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include metal, resin, ceramics, glass, and the like. Among these, metals are preferred. Examples of the metal include copper, aluminum, silver, and alloys thereof.
The material of the adherend is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include flat plate, sheet, film, and the like.
The structure of the adherend is not particularly limited and can be appropriately selected depending on the purpose, for example, it may be a single layer structure or a multilayer structure.
Specific examples of the adherend include electronic components, heat dissipation members, and the like. The electronic component is not particularly limited and can be appropriately selected depending on the purpose, and includes, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), and the like.

If the area of the resin frame becomes larger than the area of the adherend, the bonding area between the adherend and the heat dissipation member becomes smaller, so it is preferable to finely pattern the resin composition. For this reason, it is preferable to heat the adherend to such an extent that the foaming agent in the resin frame does not foam, and then quickly evaporate the solvent from the resin composition.

The height of the resin frame is preferably equal to or greater than the wet film thickness of the thermally conductive composition (liquid) corresponding to the film thickness of the thermally conductive composition (film) to be formed.
The wet film thickness of the liquid film when the thermally conductive composition (liquid) is applied is, for example, when the solid content concentration of the thermally conductive composition (liquid) is 10% by volume and the target film thickness is 20 μm. If thickness (μm)×0.1≈20 μm is used as a guideline, the wet film thickness of the liquid film is 200 μm. Therefore, it is preferable that the height of the resin frame is 200 μm or more.

<Liquid film formation process>
The liquid film forming step is a step of applying a thermally conductive composition containing a thermally conductive substance to the inside of the resin frame using an inkjet method to form a liquid film.

The thermally conductive composition preferably contains a thermally conductive substance, a resin and a solvent, and further contains other components as necessary.

-Thermally conductive material-
The thermally conductive substance is preferably in the form of particles, such as scale-like (fish scale-shaped pieces), plate-like (disc-like, hexagonal plate-like, etc.), cylindrical, prismatic, elliptical, etc. It is more preferable that the particles have the following properties.
Examples of the thermally conductive substance include metal particles such as copper, aluminum, iron, silver, zinc, and indium; aluminum oxide particles, magnesium oxide particles, boron nitride particles, talc particles, aluminum nitride particles, aluminum hydroxide particles, Examples include graphite, graphene, and carbon fiber. These may be used alone or in combination of two or more. Among these, metal particles such as silver and copper and carbon fibers are preferred because of their high thermal conductivity.

The carbon fiber is not particularly limited and can be selected as appropriate depending on the purpose, such as pitch-based carbon fiber, PAN-based carbon fiber, carbon fiber obtained by graphitizing PBO fiber, arc discharge method, laser evaporation method. Examples include carbon fibers synthesized by CVD (chemical vapor deposition), CCVD (catalytic chemical vapor deposition), and the like. These may be used alone or in combination of two or more. Among these, from the viewpoint of thermal conductivity, carbon fibers obtained by graphitizing PBO fibers, PAN-based carbon fibers, and pitch-based carbon fibers are preferred, and pitch-based carbon fibers are particularly preferred.
When using the carbon fibers, it is preferable from the viewpoint of thermal conductivity that the long axes of the carbon fibers 21 are oriented parallel to the thickness direction of the thermally conductive sheet 20, as shown in FIG.
The content of the thermally conductive substance is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10% by mass or more and 90% by mass or less based on the total amount of the resin composition.

-resin-
The resin is not particularly limited and can be appropriately selected depending on the purpose, for example, polyethylene resin, polypropylene resin, ethylene-α olefin copolymer such as ethylene-propylene copolymer; polymethylpentene resin, Fluorine polymers such as polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, ethylene-vinyl acetate copolymer, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinylidene fluoride resin, polytetrafluoroethylene; polyethylene terephthalate resin , polybutylene terephthalate resin, polyethylene naphthalate resin, polystyrene resin, polyacrylonitrile resin, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polyphenylene-ether copolymer (PPE) resin, modified PPE resin, aliphatic polyamide resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, polymethacrylic acid esters such as polymethacrylic acid, polymethacrylic acid methyl ester; polyacrylic acid, polycarbonate resin, polyphenylene sulfide resin, polysulfone resin , polyether sulfone resin, polyether nitrile resin, polyether ketone resin, polyketone resin, liquid crystal polymer, silicone resin, epoxy resin, ionomer resin and the like. These may be used alone or in combination of two or more.

-solvent-
As the solvent, the same solvent as in the resin composition can be used.

The other components are not particularly limited and can be selected as appropriate depending on the purpose, such as thixotropic agents, dispersants, curing accelerators, retarders, slight tackifiers, plasticizers, and flame retardants. , antioxidants, stabilizers, colorants, etc.

As the thermally conductive composition, a suitably manufactured one may be used, or a commercially available product may be used. The commercially available products are not particularly limited and can be selected as appropriate depending on the purpose, for example, silver paste (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., TS185sr), silver paste (manufactured by Kaken Tech Co., Ltd., CR3520, CM3212). ), etc. The silver paste preferably has a thermal conductivity of 10 W/m·K or more, and may be diluted with a solvent to have a viscosity of 200 mPa·s or less at 25°C.
If the adhesive strength of the thermally conductive composition is low, a conductive adhesive may be used together with the thermally conductive composition. When using a conductive adhesive, the film thickness is an order of magnitude thinner than that of a thermally conductive composition, so it does not require a thermal conductivity as high as that of the thermally conductive composition, and the thermal conductivity is 1 W/m. K or higher is preferred.

The thermally conductive composition is applied to the inside of the resin frame by an inkjet method.
The wet film thickness of the thermally conductive composition (liquid) is preferably 200 μm or less.
The viscosity of the thermally conductive composition at 25° C. is preferably 200 mPa·s or less, more preferably 100 mPa·s or less, and even more preferably 50 mPa·s or less. When the viscosity at 25° C. is 200 mPa·s or less, there is an advantage that ejection failure is less likely to occur even when ejected by an inkjet method.
The viscosity of the thermally conductive composition can be measured, for example, according to JIS Z 8803. The device used for measuring the viscosity is not particularly limited and can be appropriately selected depending on the purpose, and examples include TV25 type viscometer (cone plate viscometer, manufactured by Toki Sangyo Co., Ltd.). .

<Heating process>
The heating step is a step of heating the liquid film and the resin frame to solidify the liquid film and foam the resin frame, and is performed using a heating means.
The heating means is not particularly limited and can be appropriately selected depending on the purpose, and includes, for example, a hot air heater, an infrared heater, a hot plate, and the like.
In the heating step, the foaming agent in the resin frame is heated at a temperature that causes it to foam, and the resin frame is foamed and peeled off from the adherend, and a liquid film made of the thermally conductive composition (liquid) is solidified. let In the present disclosure, solidification refers to hardening of a liquid film to such an extent that it does not spread, and does not require that the entire liquid film be completely hardened. In addition, in this indication, solidification may be described as temporary hardening.
The heating in the heating step is preferably performed at a temperature of 100°C or higher and lower than 160°C. Heating at 100° C. or more and less than 160° C. allows the foaming agent in the resin frame to foam and solidify the thermally conductive composition.
The average thickness of the solidified liquid film is preferably 20 μm or more.

<Removal process>
The removal process is a process of removing the resin frame.
The resin frame is easily peeled off and removed from the adherend by being foamed by heating, so there is no need for a mechanical peeling process.

<Curing process>
The curing step is a step of removing the resin frame and then heating and curing the solidified liquid film.
The heating in the curing step is preferably performed at a temperature of 160°C or higher and 200°C or lower.
In the curing step, a heat dissipation member such as a heat sink is placed on the surface of the solidified liquid film, and by heating in this state and curing the liquid film, the heat dissipation member can be adhesively fixed onto the liquid film, and a heat dissipation structure is created. body can be manufactured.

<Other processes>
Other steps are not particularly limited and can be appropriately selected depending on the purpose, and include, for example, a cleaning step, a control step, and the like.

The thermally conductive structure manufactured by the method for manufacturing a thermally conductive structure of the present invention is in the form of a sheet or film, and can achieve high thermal conductivity. CPUs, MPUs, power transistors, LEDs, laser diodes, various batteries (various secondary batteries such as lithium ion batteries, various fuel cells, capacitors, amorphous silicon, crystalline silicon, compound semiconductors, wet solar cells, etc.) that have adverse effects It is suitable for use around various electrical devices such as batteries, etc., around the heat source of heating equipment where effective use of heat is required, around heat exchangers, and around the heat piping of floor heating equipment.

(Method for manufacturing heat dissipation structure)
The method of manufacturing a heat dissipating structure of the present invention includes the steps of the method of manufacturing a thermally conductive structure of the present invention, and further includes other steps as necessary.
The heat dissipation structure includes, for example, a heat generating body such as an electronic component, a heat dissipating member such as a heat sink, a heat pipe, a heat spreader, and a thermally conductive structure sandwiched between the heat generating body and the heat dissipating member.

The electronic component is not particularly limited and can be appropriately selected depending on the purpose, and includes, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), and the like.

The heat dissipation structure is not particularly limited as long as it dissipates heat generated by electronic components (heat generating elements), and can be appropriately selected depending on the purpose. For example, it may include a heat spreader, a heat sink, a vapor chamber, Examples include heat pipes.
The heat spreader is a member for efficiently transmitting heat from the electronic component to other components. The material of the heat spreader is not particularly limited and can be appropriately selected depending on the purpose, such as copper and aluminum. The heat spreader usually has a flat plate shape.
The heat sink is a member for releasing heat from the electronic component into the air. The material of the heat sink is not particularly limited and can be appropriately selected depending on the purpose, such as copper and aluminum. The heat sink has, for example, a plurality of fins. The heat sink includes, for example, a base portion and a plurality of fins extending in non-parallel directions (for example, perpendicular directions) to one surface of the base portion.
The heat spreader and the heat sink generally have a solid structure with no internal space.
The vapor chamber is a hollow structure. A volatile liquid is sealed in the internal space of the hollow structure. Examples of the vapor chamber include a plate-shaped hollow structure such as a hollow structure of the heat spreader and a hollow structure of the heat sink.
The heat pipe is a hollow structure having a cylindrical shape, a substantially cylindrical shape, or a flat cylindrical shape. A volatile liquid is sealed in the internal space of the hollow structure.

Here, FIG. 1 is a schematic diagram of a semiconductor device as an example of a heat dissipation structure. FIG. 1 is a schematic cross-sectional view of an example of a semiconductor device. The thermally conductive sheet 1 as a thermally conductive structure radiates heat generated by electronic components 3 such as semiconductor elements, and as shown in FIG. It is fixed and held between the electronic component 3 and the heat spreader 2. Further, the thermally conductive sheet 1 is sandwiched between the heat spreader 2 and the heat sink 5. The heat conductive sheet 1 and the heat spreader 2 constitute a heat radiating member that radiates heat from the electronic component 3.

The heat spreader 2 is formed into a rectangular plate shape, for example, and has a main surface 2a facing the electronic component 3, and a side wall 2b erected along the outer periphery of the main surface 2a. In the heat spreader 2, a heat conductive sheet 1 is provided on a main surface 2a surrounded by side walls 2b, and a heat sink 5 is provided on the other surface 2c opposite to the main surface 2a via the heat conductive sheet 1. The heat spreader 2 is formed using, for example, copper or aluminum, which has good thermal conductivity, because the higher the thermal conductivity, the lower the thermal resistance, and the more efficiently absorbs heat from the electronic components 3 such as semiconductor elements. can do.

The electronic component 3 is, for example, a semiconductor element such as a BGA, and is mounted on the wiring board 6. Further, the heat spreader 2 also has the front end surface of the side wall 2b mounted on the wiring board 6, so that the side wall 2b surrounds the electronic component 3 at a predetermined distance.
Then, by bonding the heat conductive sheet 1 to the main surface 2a of the heat spreader 2, a heat radiating member is formed that absorbs the heat generated by the electronic component 3 and radiates the heat from the heat sink 5. The heat spreader 2 and the thermally conductive sheet 1 can be bonded together using the adhesive force of the thermally conductive sheet 1 itself.

EMBODIMENT OF THE INVENTION Hereinafter, the embodiment of the manufacturing method of the thermally conductive structure of this invention is described in detail with reference to drawings. In addition, in each drawing, the same components are given the same reference numerals, and duplicate explanations may be omitted. Moreover, the number, position, shape, etc. of the following constituent members are not limited to this embodiment, and can be set to a preferable number, position, shape, etc. for implementing the present invention.

<First embodiment>
FIGS. 3A to 3C are process diagrams showing an example of the method for manufacturing the thermally conductive structure according to the first embodiment.
First, as shown in FIG. 3A, a resin composition containing p-toluenesulfonyl hydrazide (foaming temperature 110° C.) as a foaming agent is applied onto the adherend 11 using a dispenser method to form a resin composition with a height of 200 μm. A frame 12 is provided, and a silver paste (manufactured by Kaken Tech Co., Ltd., CR3520, temporary curing temperature: 130°C, viscosity at 25°C of 200 mPa·s or less) is inkjetted as a thermally conductive composition 13a on the inside of the resin frame 12. to form a liquid film.

Next, as shown in FIG. 3B, the liquid film 13b and the resin frame 12 are heated to solidify the liquid film and foam the resin frame 12. When the liquid film 13b and the resin frame 12 are heated at 120° C., the liquid film solidifies and the resin frame foams.

Next, as shown in FIG. 3C, the resin frame 12 is removed, and a flat liquid film 13b having a desired thickness is formed on the adherend.

<Second embodiment>
FIGS. 4A to 4E are process diagrams showing an example of a method for manufacturing a thermally conductive structure according to the second embodiment.

As shown in FIGS. 4A and 4B, a resin composition is applied onto the adherend 11 to form the resin frame 12. Suitable methods for applying the resin composition include methods that allow easy patterning, such as an inkjet method, a dispenser method, and screen printing.

As shown in FIG. 4C, a thermally conductive composition (liquid) 13a containing a thermally conductive substance is applied to the inside of the resin frame 12 by an inkjet method to form a liquid film.

As shown in FIG. 4D, the liquid film 13b and the resin frame 12 are heated to solidify the liquid film and foam the resin frame 12, and the resin frame 12 is removed.

As shown in FIG. 4E, a heat dissipation structure is obtained by installing the heat dissipation member 14 on the liquid film 13b and heating and curing the liquid film. When silver paste (manufactured by Kaken Tech Co., Ltd., CR3520) is used as the thermally conductive composition 13a, the curing temperature is 180°C. As the material of the heat dissipation member, materials with high thermal conductivity such as aluminum, copper, and brass can be used. Note that the exterior casing can also serve as a heat dissipation member.

Examples of aspects of the present invention are as follows.
<1> A resin frame forming step of forming a resin frame by applying a resin composition containing a resin and a foaming agent;
a liquid film forming step of forming a liquid film by applying a thermally conductive composition containing a thermally conductive substance to the inside of the resin frame using an inkjet method;
a heating step of heating the liquid film and the resin frame to solidify the liquid film and foam the resin frame;
a removing step of removing the resin frame;
A method for manufacturing a thermally conductive structure, comprising:
<2> The method for manufacturing a thermally conductive structure according to <1>, which includes a curing step of heating and curing the solidified liquid film after removing the resin frame.
<3> The method for producing a thermally conductive structure according to any one of <1> to <2>, wherein the foaming temperature of the foaming agent is 200° C. or lower.
<4> The heating in the heating step is performed at a temperature of 100°C or more and less than 160°C,
The method for manufacturing a thermally conductive structure according to any one of <2> to <3>, wherein the heating in the curing step is performed at a temperature of 160° C. or higher and 200° C. or lower.
<5> The method for producing a thermally conductive structure according to any one of <1> to <4>, wherein the thermally conductive composition has a viscosity of 200 mPa·s or less at 25°C.
<6> The method for manufacturing a thermally conductive structure according to any one of <1> to <5>, wherein the average thickness of the solidified liquid film is 20 μm or more.
<7> The thermal conductivity according to any one of <1> to <6>, wherein the thermally conductive substance is at least one selected from metal particles, boron nitride particles, aluminum oxide particles, and carbon fibers. This is a method for manufacturing a sexual structure.
<8> The method for manufacturing a thermally conductive structure according to any one of <1> to <7>, wherein the resin frame is formed by an inkjet method.
<9> A method for manufacturing a heat dissipating structure, including the step of the method for manufacturing a thermally conductive structure according to any one of <1> to <8>.

According to the method for manufacturing a thermally conductive structure according to any one of <1> to <8> above, and the method for manufacturing a heat dissipating structure according to <9> above, various problems in the past are solved, and the present invention can achieve the objectives of

1 Heat conductive sheet 2 Heat spreader 2a Main surface 3 Heating element (electronic component)
3a Upper surface 5 Heat sink 6 Wiring board 11 Adherent 12 Resin frame 13a Thermal conductive composition (liquid)
13b Liquid film 14 Heat dissipation member

International Publication No. 2016/152660 pamphlet Japanese Patent Application Publication No. 2011-200839

Claims (9)

a resin frame forming step of forming a resin frame by applying a resin composition containing a resin and a foaming agent;
a liquid film forming step of forming a liquid film by applying a thermally conductive composition containing a thermally conductive substance to the inside of the resin frame using an inkjet method;
a heating step of heating the liquid film and the resin frame to solidify the liquid film and foam the resin frame;
a removing step of removing the resin frame;
A method of manufacturing a thermally conductive structure, comprising: The method for manufacturing a thermally conductive structure according to claim 1, further comprising a curing step of heating and curing the solidified liquid film after removing the resin frame. The method for manufacturing a thermally conductive structure according to any one of claims 1 to 2, wherein the foaming temperature of the foaming agent is 200°C or less. The heating in the heating step is performed at a temperature of 100°C or more and less than 160°C,
The method for manufacturing a thermally conductive structure according to any one of claims 2 to 3, wherein the heating in the curing step is performed at a temperature of 160°C or higher and 200°C or lower. The method for manufacturing a thermally conductive structure according to any one of claims 1 to 4, wherein the viscosity of the thermally conductive composition at 25° C. is 200 mPa·s or less. The method for manufacturing a thermally conductive structure according to any one of claims 1 to 5, wherein the average thickness of the solidified liquid film is 20 μm or more. The method for manufacturing a thermally conductive structure according to any one of claims 1 to 6, wherein the thermally conductive substance is at least one selected from metal particles, boron nitride particles, aluminum oxide particles, and carbon fibers. . The method for manufacturing a thermally conductive structure according to any one of claims 1 to 7, wherein the resin frame is formed by an inkjet method. A method for manufacturing a heat dissipating structure, comprising the step of the method for manufacturing a thermally conductive structure according to any one of claims 1 to 8.