CN116348564A - Adhesive film, adhesive film with support sheet, cured body, and production method of structure - Google Patents

Abstract

The present invention provides an adhesive film 1, which is an adhesive film 1 composed of an adhesive resin composition, and the adhesive resin composition contains: graphene having a two-dimensional structure and a monolayer nitride A thermally conductive filler (A) consisting of at least one type of boron; a thermosetting component (B); and a binder polymer (C), and the adhesive film is used in a manner of subjecting the following heat treatment to The treatment includes a preheating step and a complete curing step of completely curing the adhesive film 1 after the preheating step. The preheating step is held at a temperature below the following temperature (T) for 30 minutes or more, and the temperature ( T): In the atmospheric atmosphere and under the condition of increasing the temperature from 40°C to 400°C at a heating rate of 10°C/min, the thermal gravimetric test is carried out on the adhesive film 1 before any heat treatment, the adhesive The temperature at which the weight of composite film 1 decreases by 0.5%. The adhesive film 1 described above is excellent in thermal conductivity.

Description

Adhesive film, adhesive film with support sheet, cured body and method for producing structure

technical field

The present invention relates to an adhesive film having excellent thermal conductivity, a method for producing the same, an adhesive film with a support sheet, a cured product, a method for producing the same, and a method for producing the structure.

Background technique

Conventionally, in electronic devices such as thermoelectric conversion devices, photoelectric conversion devices, and semiconductor devices such as large-scale integrated circuits, heat dissipation members having thermal conductivity are used to release heat generated by heat generation. For example, as a method for efficiently dissipating heat generated by a semiconductor device to the outside, a sheet-shaped heat dissipation member (film, sheet) excellent in thermal conductivity is provided between the semiconductor device and the heat dissipation sheet.

The above-mentioned film or sheet, as exemplified in Patent Document 1, is obtained by applying a coating solution of a heat dissipation material containing an adhesive resin, an inorganic filler, a curing agent, and a solvent on a release sheet or a base material and drying it. manufacture. As the above-mentioned inorganic filler, silica, alumina, glass, titanium oxide and the like are used.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2015-67713

Contents of the invention

The technical problem to be solved in the present invention

However, conventional films or sheets containing inorganic fillers may not always be able to obtain desired thermal conductivity. Therefore, it is necessary to further improve thermal conductivity. Among them, conventional films or sheets containing inorganic fillers, when highly filled with inorganic fillers in order to obtain high thermal conductivity, may cause process defects such as mechanical embrittlement, decreased flexibility, and generation of broken chips during use. In addition, because the surface roughness of the sheet-shaped heat dissipation member becomes large, it is difficult to express the stickiness, and the temporary adhesiveness when sticking to the adherend cannot be obtained, or when the sheet-shaped heat dissipation member is attached to the adherend When the object is easily entrapped with air, a large number of voids are formed at the bonding interface between the sheet-shaped heat dissipation member and the adherend or inside the sheet-shaped heat dissipation member, resulting in a decrease in thermal conductivity.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adhesive film having excellent thermal conductivity, a method for producing the same, an adhesive film with a support sheet, a cured body, a method for producing the same, and a method for producing the structure.

Technical means to solve technical problems

In order to achieve the above objects, the first present invention provides an adhesive film, which is characterized in that it is an adhesive film composed of an adhesive resin composition, and the adhesive resin composition contains: A thermally conductive filler (A) composed of at least one of graphene and monolayer boron nitride; a thermosetting component (B); and a binder polymer (C); wherein, it is carried out in the following heat treatment mode For use, the heat treatment includes a preheating step and a complete curing step for completely curing the adhesive film after the preheating step, and the preheating step is to keep the following temperature (T) or lower A process of more than 30 minutes,

Temperature (T): In the atmosphere and under the condition of increasing the temperature from 40°C to 400°C at a heating rate of 10°C/min, the adhesive film before any heat treatment is subjected to a thermogravimetric test, the The temperature at which the weight of the adhesive film decreases by 0.5% (Invention 1).

The adhesive film of the said invention (invention 1) can become an adhesive film excellent in thermal conductivity by containing the said specific thermally conductive filler (A) and using it for the said application.

The second present invention provides an adhesive film, which is characterized in that it is an adhesive film composed of an adhesive resin composition containing: graphene having a two-dimensional structure and a single A thermally conductive filler (A) composed of at least one type of boron nitride; a thermosetting component (B); and a binder polymer (C); wherein, the adhesive film is heat-treated under the following conditions to The area ratio of the void portion in the cross-section in the thickness direction of the obtained cured body is 10% or less,

Condition: the heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step, and the preheating step is held at a temperature below the following temperature for 30 minutes or more In the process, the temperature is: under the condition of increasing the temperature from 40°C to 400°C at a temperature increase rate of 10°C/min under the atmospheric atmosphere, when performing a thermogravimetric test on the adhesive film before any heat treatment The temperature at which the weight of the adhesive film decreases by 0.5% (Invention 2).

The adhesive film of the above-mentioned invention (Invention 2) can be excellent in thermal conductivity by containing the above-mentioned specific thermally conductive filler (A) and using it in such a manner that the above-mentioned cured body is obtained by heat treatment under the above-mentioned conditions. Adhesive film.

In the above inventions (Inventions 1 and 2), it is preferable that the content of the thermally conductive filler (A) is 5% by mass or more and 60% by mass or less (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the thermosetting component (B) is an epoxy resin (Invention 4).

In the above inventions (Inventions 1 to 4), it is preferable that they are formed by performing hot pressing (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that the arithmetic mean roughness (Ra) of at least one surface thereof is 0.01 μm or more and 0.5 μm or less (Invention 6).

The third present invention provides a method for producing an adhesive film, characterized in that, in a solvent, a thermally conductive filler (A) composed of at least one of graphene having a two-dimensional structure and monolayer boron nitride and The binder polymer (C) is mixed, and then the thermosetting component (B) is further mixed to obtain an adhesive resin composition, which is formed into a film (Invention 7).

In the above invention (Invention 7), it is preferable to further perform hot pressing after forming the adhesive resin composition into a film (Invention 8).

In the above invention (Invention 8), it is preferable that the heating temperature of the hot press is lower than the curing reaction temperature of the thermosetting component (B) (Invention 9).

In the above inventions (Inventions 8 and 9), it is preferable that the arithmetic average roughness (Ra) of at least one surface of the hot-pressed adhesive film is 0.01 μm or more and 0.5 μm or less (Invention 10).

A fourth present invention provides an adhesive film with a support sheet, comprising: the above-mentioned adhesive film (Inventions 1 to 6), and a support sheet laminated on at least one side of the adhesive film (Invention 11) .

Fifth, the present invention provides a cured body, which is characterized in that it is a cured body obtained by heat-treating an adhesive film composed of an adhesive resin composition containing: A thermally conductive filler (A) composed of at least one of two-dimensional graphene and monolayer boron nitride; a thermosetting component (B); and a binder polymer (C); a cross-section in the thickness direction of the cured body The area ratio of the void portion is 10% or less (Invention 12).

In the above invention (Invention 12), it is preferable that the maximum area of voids in a cross section in the thickness direction of the cured product is 100 μm ² or less (Invention 13).

In the above inventions (Inventions 12 and 13), it is preferable that the heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step, and the preheating step is included in the following The process of holding for 30 minutes or more at a temperature below the temperature of the product before any heat treatment is carried out under the condition of raising the temperature from 40°C to 400°C at a rate of temperature increase of 10°C/min in the air atmosphere. The temperature at which the weight of the adhesive film decreases by 0.5% when the adhesive film is subjected to a thermogravimetric test (Invention 14).

Sixth, the present invention provides a method for producing a cured body, which is characterized in that the cured body is produced by heat-treating an adhesive film composed of an adhesive resin composition, and the adhesive resin composition contains: A thermally conductive filler (A) composed of at least one of graphene with a two-dimensional structure and a single-layer boron nitride; a thermosetting component (B); and a binder polymer (C); the heat treatment includes pre- a heating step, and a complete curing step of completely curing the adhesive film after the preheating step, wherein the preheating step includes a step of maintaining for 30 minutes or more at a temperature below the following temperature: The reduction in weight of the adhesive film when the adhesive film before any heat treatment is subjected to a thermogravimetric test under the condition that the temperature is raised from 40°C to 400°C at a temperature increase rate of 10°C/min under the atmospheric atmosphere 0.5% temperature (Invention 15).

In the above invention (Invention 15), it is preferable to heat-press the adhesive film before the heat treatment (Invention 16).

In the above inventions (Inventions 15 and 16), it is preferable that the area ratio of voids in a cross section in the thickness direction of the cured body is 10% or less (Invention 17).

The seventh present invention provides a method of manufacturing a structure, characterized in that the method comprises: bonding at least a part of the first member to the second member via an adhesive film made of an adhesive resin composition. At least a part of the bonding process, wherein the adhesive resin composition contains: a thermally conductive filler (A) composed of at least one of graphene having a two-dimensional structure and a single-layer boron nitride; a thermosetting component ( B); and the binder polymer (C); after the pasting, the adhesive film is heat-treated to form a cured body, and at least a part of the first member and the second member are obtained. The process of combining at least a part of the two components through the solidified body; the heat treatment includes a pre-heating process and a complete curing process for completely curing the adhesive film after the pre-heating process, so The above-mentioned preheating process includes the process of maintaining at a temperature below the following temperature for 30 minutes or more. The temperature at which the weight of the adhesive film decreases by 0.5% when the adhesive film before any heat treatment is subjected to a thermogravimetric test (Invention 18).

In the above invention (Invention 18), it is preferable to heat press the adhesive film before the heat treatment (especially before the bonding step) (Invention 19).

In the above inventions (Inventions 18 and 19), it is preferable that the area ratio of voids in a cross section in the thickness direction of the cured body is 10% or less (Invention 20).

In the above inventions (Inventions 18 to 20), it is preferable that in the laminating step, the display peak of the loss tangent (tan δ) obtained in the viscoelasticity measurement of the adhesive film before any heat treatment is performed The bonding is carried out at a temperature equal to or higher than the temperature above (Invention 21).

In the above inventions (Inventions 18 to 20), it is preferable that the first member is a flexible sheet-like member, and the method includes lamination of the sheet-like member and the hot-pressed adhesive film. In accordance with the step of the second member, the bonding is carried out at a temperature equal to or higher than the peak temperature of the loss tangent (tan δ) obtained in the viscoelasticity measurement of the adhesive film before any heat treatment. combine.

In the above inventions (Inventions 18 to 20), it is preferable to include a step of bonding the adhesive film to the first member or the second member so that the adhesive film before any heat treatment is The bonding is carried out at a temperature equal to or higher than the temperature at which the peak of the loss tangent (tan δ) obtained in the viscoelasticity measurement is displayed.

Invention effect

The adhesive film, the adhesive film with a support sheet, the cured body, and the structure of the present invention are excellent in thermal conductivity. Moreover, according to the manufacturing method of the adhesive film of this invention, the adhesive film excellent in thermal conductivity can be manufactured. Furthermore, according to the method for producing a cured body of the present invention, a cured body excellent in thermal conductivity can be produced, and according to the method for producing a structured body of the present invention, a structured body excellent in thermal conductivity can be produced.

Description of drawings

Fig. 1 is a cross-sectional view of an adhesive film with a support sheet according to one embodiment of the present invention.

Fig. 2 is a cross-sectional view of a structure according to an embodiment of the present invention.

Fig. 3 is an image of a cross section of a cured body of an adhesive film (Example 1) obtained by a scanning electron microscope (SEM).

4 is an image obtained by binarizing a cross-sectional image of a cured body of an adhesive film (Example 1) obtained by a scanning electron microscope (SEM).

5 is an image of a cross-section of a cured body of an adhesive film (Comparative Example 2) obtained by a scanning electron SEM microscope (SEM).

6 is an image obtained by binarizing a cross-sectional image of a cured body of an adhesive film (Comparative Example 2) obtained by a scanning electron microscope (SEM).

Detailed ways

Embodiments of the present invention will be described below.

[adhesive film]

The adhesive film of the present embodiment is composed of an adhesive resin composition (hereinafter sometimes referred to as "adhesive resin composition R") containing: graphite having a two-dimensional structure A thermally conductive filler (A) composed of at least one of alkene and monolayer boron nitride; a thermosetting component (B); and a binder polymer (C). The adhesive resin composition R preferably contains a curing agent (D) if necessary, and more preferably contains a curing accelerator (E).

The adhesive film of the present embodiment is firstly used in a manner of performing heat treatment including a preheating step and a complete curing step of completely curing the adhesive film after the preheating step. The step preferably includes a step of holding at a temperature not higher than the following temperature (T) for 30 minutes or more. By performing this heat treatment, voids are reduced in the obtained cured body. Specifically, the area ratio of the void portion in the cross section in the thickness direction of the obtained cured body can be 10% or less. Details of the heat treatment will be described later.

Temperature (T): In the atmosphere and under the condition of heating up from 40°C to 400°C at a heating rate of 10°C/min, the thermal gravimetric test is carried out on the adhesive film before any heat treatment. The temperature at which the weight of the film decreases by 0.5%.

In addition, in the adhesive film of the present embodiment, secondly, it is preferable that the area ratio of voids in a cross-section in the thickness direction of a cured product obtained by heat-treating the adhesive film under the following conditions is 10% or less.

(condition)

The heat treatment includes a preheating step and a complete curing step for completely curing the adhesive film after the preheating step,

The above-mentioned preheating step is a step of maintaining for 30 minutes or more at a temperature below the temperature: under the condition of increasing the temperature from 40° C. to 400° C. at a temperature increase rate of 10° C./min. The temperature at which the weight of the adhesive film decreases by 0.5% when the adhesive film is subjected to a thermogravimetric test before any heat treatment.

The thermally conductive filler (A) composed of at least one of graphene having a two-dimensional structure and single-layer boron nitride has a two-dimensional structure on the order of tens of nanometers in thickness, and thus has a large specific surface area. Therefore, in the adhesive film, the thermally conductive fillers (A) are in contact with each other, and it is easy to form a heat conduction path for transferring heat. In particular, by performing a predetermined heat treatment as described above and using it, the voids inside the obtained cured body can be reduced, and thus, even a small amount of the thermally conductive filler (A) can be added. thermal conductivity. That is, when the above-mentioned thermally conductive filler (A) is used as the filler of the adhesive resin composition, excellent thermal conductivity can be imparted without highly filling. In addition, the above-mentioned thermally conductive filler (A) has a two-dimensional structure with a thickness of several tens of nanometers and has intrinsic flexibility. Therefore, an adhesive film containing the thermally conductive filler (A) is excellent in flexibility. In addition, since it is not necessary to highly fill the thermally conductive filler (A) as described above, mechanical embrittlement of the adhesive film can be suppressed.

If the adhesive film has excellent flexibility, it is difficult to entrain air when it is attached to an adherend, and it is possible to suppress the occurrence of voids at the interface between the adhesive film and the adherend, and it is possible to increase the contact between the adhesive film and the adherend. area. That is, it is possible to suppress an increase in thermal resistance due to voids at the interface between the adhesive film and the adherend, and it is possible to make the thermal conductivity between the adhesive film and the adherend excellent. In addition, if the mechanical embrittlement of the adhesive film is suppressed as described above, the probability of occurrence of process defects such as chipping during use becomes small.

Furthermore, if the conventional inorganic filler is highly filled in order to obtain desired thermal conductivity, the surface roughness of the adhesive film becomes large, making it difficult to express tackiness. On the other hand, since the thermally conductive filler (A) of the present embodiment can obtain high thermal conductivity even if it is not highly filled as described above, it is possible to reduce the surface roughness of the adhesive film, thereby enabling the When the adhesive film is attached to an adherend, an appropriate adhesive force can be exhibited by adjusting the attachment temperature.

1. Ingredients

(1) Thermally conductive filler (A)

The thermally conductive filler (A) of this embodiment is composed of at least one of graphene having a two-dimensional structure and monolayer boron nitride. Graphene has a two-dimensional structure in which carbon atoms are regularly arranged in hexagons, and monolayer boron nitride is a two-dimensional compound with a two-dimensional structure in which boron atoms and nitrogen atoms are regularly arranged in hexagons, and is composed of the original layer of atoms . The "graphene or single-layer boron nitride having a two-dimensional structure" in this specification may be a plurality of layers, and the compound preferably has a thickness of 1/10 or less of the shortest length of the top view shape. In addition, graphene in this specification also includes graphene produced by thinly exfoliating graphite, and single-layer boron nitride also includes single-layer boron nitride produced by thinly exfoliating boron nitride. In this specification, graphite itself does not belong to "graphene having a two-dimensional structure".

As mentioned above, graphene or monolayer boron nitride having a two-dimensional structure may be a single layer or a plurality of layers. When it is a plurality of layers, it is usually about 2 to 1,000 layers. The plan view shapes of graphene and single-layer boron nitride having a two-dimensional structure are not particularly limited.

The average particle diameter of the thermally conductive filler (A) is preferably 0.5 μm or more, more preferably 1.0 μm or more, particularly preferably 3.0 μm or more, further preferably 5.0 μm or more. Thereby, each thermally conductive filler (A) becomes easy to contact each other, and it becomes easy to form a thermal conduction path which transfers heat, Therefore The characteristic of a two-dimensional structure functions, and the obtained adhesive film becomes excellent in thermal conductivity. In addition, the average particle diameter of the thermally conductive filler (A) is preferably 30 μm or less, particularly preferably 20 μm or less, further preferably 15 μm or less. Thereby, a dispersed state can be maintained in other materials such as a solvent and the binder polymer (C), and it is possible to suppress failure to form a heat conduction path due to segregation, so that the thermal conductivity of the adhesive film is further improved.

In addition, the thickness of the thermally conductive filler (A) is preferably 500 nm or less, more preferably 300 nm or less, particularly preferably 200 nm or less, further preferably 100 nm or less. Thereby, favorable flexibility can be maintained in the obtained adhesive film. On the other hand, the lower limit of the thickness of the thermally conductive filler (A) is not particularly limited, but is usually 0.7 nm or more, preferably 5.0 nm or more, particularly preferably 10 nm or more, and more preferably 15 nm or more from the viewpoint of thermal conductivity. above.

The content of the thermally conductive filler (A) in the adhesive resin composition R is preferably at least 5% by mass, more preferably at least 10% by mass, particularly preferably at least 15% by mass, and even more preferably at least 20% by mass. By setting the lower limit of the content of the thermally conductive filler (A) to the above-mentioned value, each thermally conductive filler (A) becomes easy to contact with each other, easily forms a heat conduction path for transferring heat, and the obtained adhesive film becomes more thermally conductive. excellent.

In addition, the content of the thermally conductive filler (A) in the adhesive resin composition R is preferably 60% by mass or less, more preferably 55% by mass or less, particularly preferably 50% by mass or less, further preferably 40% by mass or less. By setting the upper limit of the content of the heat conductive filler (A) to the above-mentioned value, mechanical embrittlement of the obtained adhesive film can be suppressed, and the flexibility is more excellent. In the present embodiment, by using the thermally conductive filler (A) and performing the prescribed heat treatment as described above, desired thermal conductivity can be obtained even at a relatively small content as described above.

(2) Thermosetting component (B)

The thermosetting component (B) in this embodiment is not particularly limited as long as it can thermally cure the adhesive resin composition R and express adhesiveness by thermal curing, and examples thereof include epoxy resins and phenolic resins. , Melamine resin, urea resin, polyester resin, urethane resin, acrylic resin, polyimide resin, benzoxazine resin, phenoxy resin, etc. These components may be used alone or in combination of two or more. Among them, epoxy resins are preferable from the viewpoint of the dispersibility and adhesiveness of the thermally conductive filler (A). In addition, for convenience, the "epoxy resin" in this specification also includes unpolymerized or low-molecular-weight epoxy compounds.

Examples of epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; butylene glycol, polyethylene glycol, polypropylene glycol, and the like; Glycidyl ethers of alcohols; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; aniline isocyanurate, etc. Glycidyl-type or alkylglycidyl-type epoxy resins made of active hydrogen; vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate Ester, 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, etc. pass the carbon-carbon double bond in the molecule For example, so-called alicyclic epoxides that introduce epoxy groups by oxidation. In addition, epoxy resins and polyfunctional epoxy resins having a biphenyl skeleton, a triphenylmethane skeleton, a dicyclopentadiene skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, an anthracene skeleton, and the like can also be used. These epoxy resins can be used alone or in combination of two or more.

As the thermosetting component (B) in this embodiment, it is preferable to use at least an epoxy resin having a π-conjugated mesogen skeleton from the viewpoint of dispersibility of the thermally conductive filler (A). As the epoxy resin having a π-conjugated mesogenic skeleton, an epoxy resin having a naphthalene skeleton or an epoxy resin having a biphenyl skeleton is preferable, and an epoxy resin having a naphthalene skeleton is particularly preferable. As an epoxy resin which has a naphthalene skeleton, For example, the compound represented by following formula (1) is mentioned preferably.

[chemical formula 1]

In formula (1), n is an integer of 0 or more.

The epoxy equivalent of the epoxy resin having the π-conjugated mesogen-like skeleton is preferably 100 g/eq or more, particularly preferably 150 g/eq or more, and further preferably 180 g/eq or more. In addition, the above-mentioned epoxy equivalent is preferably 500 g/eq or less, particularly preferably 400 g/eq or less, and further preferably 300 g/eq or less. Thereby, the dispersibility of a thermally conductive filler (A) becomes more excellent, and it becomes easy to express the adhesive characteristic by an epoxy group. In addition, the epoxy equivalent in this specification is the value measured based on JISK7236.

The softening point of the epoxy resin having the aforementioned π-conjugated mesogen-like skeleton is preferably 40°C or higher, particularly preferably 50°C or higher, and further preferably 60°C or higher. In addition, the aforementioned softening point is preferably 200°C or lower, particularly preferably 150°C or lower, and further preferably 120°C or lower. Thereby, the dispersibility of a heat conductive filler (A) becomes more excellent. In addition, the softening point in this specification is the value measured based on the measuring method by the ring-and-ball method described in JISK7234:1986.

As the thermosetting component (B) in this embodiment, it is preferable to use glycidyl ether of phenols in addition to the above-mentioned epoxy resin having a π-conjugated mesogen-like skeleton from the viewpoint of adjusting tackiness and adhesiveness. . Glycidyl ethers of phenols include the above-mentioned glycidyl ethers of phenols, and among them, bisphenol F-type epoxy resins are preferably used.

The epoxy equivalent of the glycidyl ether of the above-mentioned phenols is preferably 100 g/eq or more, particularly preferably 120 g/eq or more, and further preferably 150 g/eq or more. In addition, the above-mentioned epoxy equivalent is preferably 500 g/eq or less, particularly preferably 400 g/eq or less, and further preferably 300 g/eq or less. Thereby, the adhesiveness and adhesiveness of the adhesive film obtained are more excellent.

The content of the thermosetting component (B) in the adhesive resin composition R is preferably at least 5% by mass, more preferably at least 10% by mass, particularly preferably at least 15% by mass, and even more preferably at least 20% by mass. By setting the lower limit of the content of the thermosetting component (B) to the above value, the hardening of the adhesive resin composition R becomes sufficient, and further excellent mechanical strength and adhesiveness can be expressed. In addition, the above content is preferably 45% by mass or less, more preferably 40% by mass or less, particularly preferably 35% by mass or less, further preferably 30% by mass or less. By setting the upper limit of the content of the thermosetting component (B) to the above-mentioned value, the content of other components can be ensured.

When an epoxy resin having a π-conjugated mesogenic skeleton and a glycidyl ether of phenols are used together, their blending ratio (based on mass) is preferably 20:80 to 95:5, more preferably 40:60 to 90 :10, particularly preferably 50:50 to 85:15, more preferably 60:40 to 80:20. Thereby, the balance of the dispersibility of a thermally conductive filler (A), the tackiness of an adhesive film, and adhesiveness can be achieved favorably.

(3) Binder polymer (C)

The binder polymer (C) is blended in order to form the adhesive resin composition R into a film, or to impart appropriate tackiness to the obtained adhesive film. As such a binder polymer, for example, acrylic polymers, polyester resins, phenoxy resins, urethane resins, silicone resins, rubber polymers, etc. can be used, and acrylic polymers are particularly preferably used.

As an acrylic polymer, the (meth)acrylate polymer obtained by polymerizing a (meth)acrylate monomer etc. is mentioned, for example. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, the concept of "copolymer" is also included in "polymer".

As monomers constituting (meth)acrylate polymers, for example, alkyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, etc. In addition to the alkyl (meth)acrylate having 1 to 18 carbon atoms, functional group-containing monomers having a functional group in the molecule, and the like can be exemplified. As the functional group-containing monomer, preferably, for example, a monomer having a hydroxyl group in the molecule (hydroxyl-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer), a monomer having an amino group in the molecule (amino group-containing monomer ). These monomers may be used alone or in combination of two or more.

In this embodiment, the (meth)acrylate polymer used as the binder polymer (C) is preferably an alkyl (meth)acrylate with an alkyl group having 1 to 18 carbon atoms and A compound formed by copolymerization of functional group monomers. The number of carbon atoms of the alkyl group in the alkyl (meth)acrylate is preferably 1-9, particularly preferably 1-6, and further preferably 1-3. As the alkyl (meth)acrylate, methyl (meth)acrylate is particularly preferred, and methyl acrylate is most preferred.

As the functional group-containing monomer, a hydroxyl group-containing monomer is preferable. Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, Hydroxyalkyl (meth)acrylates such as hydroxybutyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. Among them, 2-hydroxyethyl (meth)acrylate is particularly preferred, and 2-hydroxyethyl acrylate is most preferred.

By using the above-mentioned monomer, it becomes easy to disperse|distribute thermally conductive filler (A) in adhesive resin composition R favorably.

When the above-mentioned (meth)acrylate polymer obtained by copolymerizing an alkyl (meth)acrylate and a functional group-containing monomer is used as the binder polymer (C), it is preferable to polymerize the (meth)acrylate The structural unit derived from the functional group-containing monomer is contained in the range of 5 to 50% by mass, particularly preferably in the range of 8 to 30% by mass, and more preferably in the range of 10 to 20% by mass. The range contains structural units derived from functional group-containing monomers.

The weight average molecular weight of the acrylic polymer ((meth)acrylate polymer) as the binder polymer (C) is preferably 50,000 or more, more preferably 100,000 or more, particularly preferably 150,000 or more, and even more preferably more than 200,000. In addition, the above weight average molecular weight is preferably 1 million or less, more preferably 700,000 or less, particularly preferably 500,000 or less, further preferably 400,000 or less. When the weight average molecular weight is in the above range, film formability and adhesiveness become favorable, and the dispersibility of a heat conductive filler (A) becomes favorable further. In addition, the weight average molecular weight in this specification is the standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

In addition, the glass transition temperature (Tg) of the acrylic polymer ((meth)acrylate polymer) as the binder polymer (C) is preferably -20°C or higher, more preferably -15°C or higher, Especially preferably -10°C or higher, more preferably -5°C or higher. In addition, the above-mentioned glass transition temperature (Tg) is preferably 60°C or lower, more preferably 50°C or lower, particularly preferably 40°C or lower, further preferably 35°C or lower. When the glass transition temperature (Tg) is within the above range, film formability and adhesiveness become favorable, and the dispersibility of the heat conductive filler (A) becomes further favorable. In addition, the glass transition temperature (Tg) of the (meth)acrylate polymer in this specification is the value calculated from FOX formula.

The content of the binder polymer (C) in the adhesive resin composition R is preferably at least 1% by mass, more preferably at least 2% by mass, particularly preferably at least 3% by mass, further preferably at least 4% by mass. In addition, the above content is preferably 60% by mass or less, more preferably 50% by mass or less, particularly preferably 45% by mass or less, further preferably 40% by mass or less. By setting the content of the binder polymer (C) within the above range, the mechanical strength and adhesiveness of the cured product of the adhesive film can be well maintained, and the film formability and adhesiveness become good, and thermal conductivity The dispersibility of the filler (A) becomes better.

(4) Curing agent (D)

The adhesive resin composition R in this embodiment preferably further contains a curing agent (D). Thereby, adhesive resin composition R can be hardened favorably.

The curing agent (D) is not particularly limited as long as it is a compound capable of curing the thermosetting component (B) by heating, and preferably includes phenols, amines, mercaptans, etc. Choose appropriately. For example, when an epoxy resin is used as the thermosetting component (B), phenols are preferable from the viewpoint of reactivity with the epoxy resin and the like. In addition, from the viewpoint of the dispersibility of the thermally conductive filler (A), it is preferable to use a compound having a π-conjugated mesogenic structure, and it is particularly preferable to use a phenol having a π-conjugated mesogenic structure.

Examples of phenols include bisphenol A, tetramethylbisphenol A, diallyl bisphenol A, biphenol, bisphenol F, diallyl bisphenol F, triphenylmethane type phenol , tetraphenol, novolac phenolic resin, cresol novolak resin, biphenyl phenolic resin, etc. Examples of the phenols having a conjugated mesogenic skeleton include the above-mentioned biphenyl-type phenols. These can be used individually by 1 type or in combination of 2 or more types.

Among the above, a novolak-type phenolic resin or a biphenyl-type phenolic resin is preferable, and it is particularly preferable to use both of the novolac-type phenolic resin and the biphenyl-type phenolic resin in combination.

The hydroxyl equivalent of the novolak-type phenolic resin is preferably 70 g/eq or more, particularly preferably 80 g/eq or more, and further preferably 90 g/eq or more. In addition, the above-mentioned hydroxyl equivalent is preferably 300 g/eq or less, particularly preferably 280 g/eq or less, further preferably 250 g/eq or less. Thereby, the curability of an epoxy resin becomes more excellent. In addition, the hydroxyl equivalent in this specification is the value measured based on JISK0070.

As a biphenyl type phenolic resin, Preferably, the compound represented by following formula (2) and a formula (3) is mentioned, for example.

[chemical formula 2]

In formula (2), n is an integer of 1 or more.

[chemical formula 3]

The hydroxyl equivalent of the biphenyl-type phenolic resin is preferably 80 g/eq or more, particularly preferably 85 g/eq or more, and further preferably 90 g/eq or more. In addition, the above-mentioned hydroxyl equivalent is preferably 300 g/eq or less, particularly preferably 280 g/eq or less, further preferably 250 g/eq or less. Thereby, it is possible to prevent the inclusion of a substance that inhibits the curing reaction remaining as an unreacted product at the time of synthesis, such as a phenol monomer, and to further improve the curability of the epoxy resin.

The softening point of the above-mentioned novolak-type phenolic resin and biphenyl-type phenolic resin is preferably 60° C. or higher, particularly preferably 80° C. or higher, and further preferably 90° C. or higher. In addition, the aforementioned softening point is preferably 200°C or lower, particularly preferably 150°C or lower, further preferably 130°C or lower. When the above-mentioned novolak-type phenolic resin or biphenyl-type phenolic resin does not soften, it is preferable that its sublimation temperature is 270° C. or higher. In addition, the above-mentioned sublimation temperature is preferably 330° C. or lower. If it has a high softening point or a high sublimation temperature, the interaction by π electrons is effectively expressed, and the dispersibility of the thermally conductive filler (A) is more excellent.

The content of the curing agent (D) in the adhesive resin composition R is preferably at least 2% by mass, more preferably at least 4% by mass, particularly preferably at least 5% by mass, and even more preferably at least 8% by mass. In addition, the above content is preferably 40% by mass or less, more preferably 35% by mass or less, particularly preferably 30% by mass or less, further preferably 25% by mass or less. By making content of a hardening|curing agent (D) into the said range, the curability of adhesive resin composition R becomes more favorable.

When using novolac type phenolic resin and biphenyl type phenolic resin at the same time, their blending ratio (mass basis) is preferably 80:20～10:90, more preferably 70:30～20:80, especially preferably 65: 35 to 25:75, more preferably 60:40 to 30:70. Thereby, the curability of the adhesive resin composition R and the dispersibility of a thermally conductive filler (A) can be well balanced.

(5) Curing accelerator (E)

The adhesive resin composition R in this embodiment preferably further contains a curing accelerator (E) that accelerates or adjusts the reaction between the thermosetting component (B) and the curing agent (D).

Examples of the curing accelerator (E) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; Imidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethyl Imidazoles such as imidazole; organic phosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine; tetraphenylphosphonium tetraphenylborate, triphenylphosphonium tetraphenyl borate, etc. boron salt etc. These can be used individually by 1 type or in mixture of 2 or more types.

When an epoxy resin is used as the thermosetting component (B) and a phenol is used as the curing agent (D), from the viewpoints of the reactivity of these compounds, storage stability, physical properties of the cured product, and curing speed, it is preferable to use imidazoles. As a curing accelerator, 2-phenyl-4,5-hydroxymethylimidazole is particularly preferably used.

The content of the curing accelerator (E) in the adhesive resin composition R is preferably at least 0.0001% by mass, more preferably at least 0.001% by mass, particularly preferably at least 0.005% by mass, and even more preferably at least 0.01% by mass. In addition, the above content is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, further preferably 0.05% by mass or less. By making content of a hardening accelerator (E) into the said range, the storage stability of an adhesive film becomes favorable, and adhesive resin composition R can be hardened favorably.

(6) Various additives

In the adhesive resin composition in the present embodiment, various additives such as tackifiers, flame retardants, antioxidants, light stabilizers, softeners, rust inhibitors, and the like can be added as necessary.

2. Preparation of Adhesive Resin Composition

The adhesive resin composition R in this embodiment can be obtained by sufficiently mixing a thermally conductive filler (A) composed of at least one of graphene having a two-dimensional structure and a single-layer boron nitride, and a thermosetting component (B). , a binder polymer (C), and if necessary, a curing agent (D), a curing accelerator (E), an additive, and a solvent are obtained. In addition, when any of the above-mentioned components is used as a solid substance, or when it is mixed with other components in an undiluted state to cause precipitation, etc., the component may be dissolved or diluted in a solvent in advance, Mix with other ingredients.

For the adhesive resin composition R in this embodiment, it is preferable to mix the thermally conductive filler (A) and the binder polymer (C) in a solvent in advance, and then add a thermosetting component (B), and Added curing agent (D), curing accelerator (E), additives, etc. By mixing the thermally conductive filler (A) with the binder polymer (C) before blending the thermosetting component (B) etc., the dispersibility of the thermally conductive filler (A) becomes better, and the thermal conductivity in the coating film can be suppressed. The filler (A) segregates. As a result, the thermally conductive filler (A) is uniformly dispersed in the obtained adhesive film, and an adhesive film more excellent in thermal conductivity can be obtained.

The mixing of the thermally conductive filler (A) and the binder polymer (C) is preferably carried out in a solvent with stirring at a speed of 500 to 5000 rpm in a disperser for 10 minutes or more, more preferably at a speed of 1000 to 40000 rpm for 20 minutes. minutes or more.

In addition, the solvent is not particularly limited, and for example, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and dichloroethane; methanol , ethanol, propanol, butanol, 1-methoxy-2-propanol and other alcohols; acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones; ethyl acetate, Esters such as butyl acetate; cellosolve solvents such as ethyl cellosolve; N,N-dimethylformamide, trimethyl-2-pyrrolidone, butyl carbitol, etc., preferably methyl ethyl base ketones.

The viscosity of the coating solution of the adhesive resin composition R prepared in this way is not particularly limited as long as it is within the range that can be coated, and can be appropriately selected depending on the situation. In addition, the addition of a diluting solvent and the like is not essential, and the diluting solvent may not be added as long as the adhesive resin composition R has a coating-readable viscosity and the like.

3. Fabrication of Adhesive Film

The adhesive film of this embodiment can be obtained by forming the adhesive resin composition R obtained above into a film form. When forming the adhesive resin composition R into a film form, it is preferable to use a release sheet as a coating object. For example, the adhesive film of this embodiment can be manufactured easily by apply|coating the coating liquid of the adhesive resin composition R on a release sheet, and removing a dilution solvent by heat drying.

A resin film, a nonwoven fabric, paper, etc. are mentioned as a release sheet, Usually, a resin film is used. As the resin film, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, Glycol ester film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. In addition, crosslinked films of these films can also be used. Furthermore, these laminated films may also be used.

It is preferable to perform a release treatment on the release surface (surface in contact with the adhesive resin composition R) of the release sheet. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. However, this peeling treatment is not necessarily necessary.

The thickness of the release sheet is not particularly limited, but is usually about 20 to 150 μm.

The arithmetic mean roughness (Ra) of the release surface of the release sheet is preferably 0.1 μm or less, more preferably 0.05 μm or less, particularly preferably 0.01 μm or less. By setting the arithmetic mean roughness (Ra) of the peeling surface of the release sheet to the above value, even if the roughness of the peeling surface of the release sheet is transferred to the adhesive film, it is easy to adjust the arithmetic average roughness (Ra) of the adhesive film to adjusted to be within the preferred range described later. In addition, the measuring method of the arithmetic mean roughness (Ra) in this specification is as shown in the test example mentioned later.

As a production example of an adhesive film, the coating liquid of the adhesive resin composition R is apply|coated to the release surface of a release sheet. As the coating method, for example, a bar coating method, a blade coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. can be utilized.

Next, the coating film of the adhesive resin composition R is dried, and the diluent solvent and the like are volatilized to obtain an adhesive film. The drying conditions are preferably at 90 to 150°C for 0.5 to 30 minutes, particularly preferably at 100 to 120°C for 1 to 10 minutes. In addition, it is necessary to set the heating temperature of the drying treatment to a temperature lower than the thermosetting temperature of the adhesive resin composition R.

After the above-mentioned drying treatment, it is preferable to laminate another peelable protective film on the exposed surface of the adhesive film to protect the adhesive film. At this time, the protective film is stacked so that the peelable surface of the protective film is in contact with the exposed surface of the adhesive film. In this way, a laminate composed of release sheet/adhesive film/protective film can be obtained.

As the protective film, the same film as that of the above-mentioned release sheet mainly composed of a resin film can be used. The protective film should just have releasability with respect to the adhesive film, regardless of whether it has peeling treatment or not.

The adhesive film (laminate) obtained as described above is preferably subjected to hot pressing. By hot-pressing the adhesive film, the voids existing inside the adhesive film can be reduced, and the thermal conductivity becomes more excellent. Specifically, thermally conductive fillers (A) are more likely to be in contact with each other by hot pressing, thereby forming a heat conduction path more easily, and the thermal conductivity of the adhesive film becomes more excellent. By performing this hot pressing, the compounding quantity of the thermally conductive filler (A) in an adhesive film can be reduced further, and the flexibility and adhesiveness of an adhesive film can be improved further.

In the adhesive film of this embodiment, by performing the above-mentioned preheating step including holding at a temperature not higher than the specific temperature (T) for 30 minutes or more, and completely curing the adhesive film after the preheating step, The heat treatment in the complete curing step is easy to control the area ratio of the void portion in the thickness direction of the obtained cured body to 10% or less, but it is easier to control the area ratio of the void portion at the same time by performing the above-mentioned hot pressing. 10% or less.

The heating temperature of the hot press is lower than the curing reaction temperature of the thermosetting component (B). Specifically, it is preferably 30 to 90°C, more preferably 40 to 80°C, particularly preferably 45 to 70°C, and even more preferably 45 to 60°C.

The pressure of hot pressing is preferably 0.5 to 15 MPa, more preferably 1 to 10 MPa, particularly preferably 1.5 to 5 MPa, even more preferably 2 to 4 MPa.

The time for hot pressing is preferably 0.5 to 60 minutes, more preferably 1 to 50 minutes, particularly preferably 2 to 40 minutes, and even more preferably 3 to 30 minutes.

By setting the conditions of hot pressing as described above, it is easy to control the various physical properties of the cured product obtained by curing the adhesive film within the preferred ranges described below.

4. Physical properties of the adhesive film

(1) The thickness of the adhesive film

The thickness (value measured in accordance with JIS K7130) of the adhesive film of this embodiment (including an adhesive film that has not been hot-pressed and an adhesive film that has been hot-pressed) is preferably 0.5 μm or more in terms of the following limit, more preferably It is preferably 1 μm or more, particularly preferably 5 μm or more, and further preferably 10 μm or more. If the lower limit of the thickness of an adhesive film is the said value, it will become easy to exhibit favorable adhesive force and cohesive force.

In addition, the upper limit of the thickness of the adhesive film of this embodiment is preferably 1000 μm or less, more preferably 500 μm or less, particularly preferably 200 μm or less, further preferably 100 μm or less. Thermal conductivity becomes more excellent as the upper limit of the thickness of an adhesive film is the said value. In addition, the adhesive film may be formed of a single layer or may be formed by laminating a plurality of layers.

(2) Arithmetic mean roughness (Ra)

The arithmetic average roughness (Ra) of at least one surface of the adhesive film (including an adhesive film that has not been hot-pressed and an adhesive film that has been hot-pressed) is preferably 0.5 μm or less, more preferably 0.4 μm or less, It is particularly preferably 0.35 μm or less, further preferably 0.3 μm or less. When the upper limit of the arithmetic mean roughness (Ra) of the adhesive film is set to the above value, the adhesiveness to an adherend, that is, the temporary adhesiveness becomes more excellent, and the handleability becomes favorable. In addition, since the contact area with the adherend becomes larger, the thermal conductivity with the adherend becomes more excellent. When the arithmetic mean roughness (Ra) exceeds the upper limit, the thermally conductive filler (A) may segregate on the surface of the adhesive film, and the resin component may not exist at all on the surface of the adhesive film, or may exist in a small amount. As a result, temporary adhesiveness becomes insufficient when sticking to an adherend.

On the other hand, the arithmetic average roughness (Ra) of the adhesive film is preferably 0.01 μm or more, more preferably 0.02 μm or more, particularly preferably 0.03 μm or more, and further preferably 0.05 μm or more. When the thermally conductive filler (A) segregates on the surface of the adhesive film, the arithmetic mean roughness (Ra) tends to increase. By setting the lower limit of the arithmetic mean roughness (Ra) of the adhesive film to the above value, it can be said that the thermally conductive filler (A) exists on the surface of the adhesive film and the thermal conductivity with the adherend becomes more excellent.

(3) Adhesion

The adhesive force of the adhesive film (including the adhesive film that has not been hot-pressed and the adhesive film that has been hot-pressed) to the silicon wafer (arithmetic average roughness (Ra): 0.02 μm or less) is preferably 0.1 mN/25 mm or more , more preferably 0.5 mN/25 mm or more, particularly preferably 0.8 mN/25 mm or more, even more preferably 1.0 mN/25 mm or more. Thereby, good adhesion can be made to an adherend, and excellent temporary adhesiveness can be exhibited.

The upper limit of the adhesive force is not particularly limited, but is usually preferably 5.0 mN/25 mm or less, more preferably 3.0 mN/25 mm or less, particularly preferably 2.5 mN/25 mm or less, and still more preferably 2.0 mN/25 mm or less. Thereby, reworkability becomes excellent. In addition, the adhesive force in this specification is basically the adhesive force measured by the 180 degree peeling method based on JIS Z0237:2009, and the specific measuring method is shown in the test example mentioned later.

(adhesive film with support sheet)

An adhesive film with a support sheet according to an embodiment of the present invention includes: the above-mentioned adhesive film (including an adhesive film that has not been heat-pressed and an adhesive film that has been heat-pressed); A support sheet for at least one face side of the membrane. The support sheet may be a support sheet which can be peeled off from the adhesive film in the future.

By supporting the adhesive film with a support sheet, for example, the processability of an adherend can be improved. As an example, even when it is difficult to process an adherend with a single adhesive film, it is possible to attach an adhesive film with a support sheet to one adherend, perform processing in this state, and then peel off the support The process of attaching an adhesive film to another adherend.

An adhesive film with a support sheet as an example of this embodiment is shown in FIG. 1 . The adhesive film 2 with a support sheet shown in FIG. 1 includes an adhesive film 1, a support sheet 11 laminated on one surface of the adhesive film 1 (the upper surface in FIG. The release sheet 12 on the other surface (the lower surface in FIG. 1 ) of the film 1 is bonded. This is laminated|stacked on the adhesive film 1 so that the peelable surface of the release sheet 12 may contact the adhesive film 1. In addition, the release sheet 12 protects the adhesive film 1 until the adhesive film 1 is used, and the release sheet 12 may be omitted. In addition, in the adhesive film with a support sheet of this embodiment, a protective film may be laminated instead of the release sheet 12 .

The support sheet 11 is not particularly limited as long as it can exhibit sufficient mechanical strength for supporting the adhesive film 1 . As a material which comprises the support sheet 11, resin film, a nonwoven fabric, paper etc. are mentioned, for example, Usually, a resin film is used.

Specific examples of the resin film include polyethylene films such as low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films, polypropylene films, ethylene-propylene copolymers, etc. Polyolefin films such as polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film; ethylene-vinyl acetate copolymer film, Ethylene-based copolymer films such as ethylene-(meth)acrylic acid copolymer films and ethylene-(meth)acrylate copolymer films; polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; polyethylene terephthalic acid Polyester films such as ethylene glycol ester films and polybutylene terephthalate films; polyurethane films; polyimide films; polystyrene films; polycarbonate films; fluororesin films, etc. In addition, modified membranes such as crosslinked membranes and ionomer membranes of these membranes can also be used. Furthermore, it may be a laminated film obtained by laminating a plurality of the above-mentioned films of the same type or different types. In addition, the support sheet 11 may be a release sheet. The support sheet 11 may be, for example, a support sheet in which a known adhesive layer is provided on the above-mentioned resin film, nonwoven fabric, paper, or the like.

The thickness of the support sheet 11 is preferably 20 μm or more, particularly preferably 40 μm or more, and further preferably 60 μm or more. In addition, the thickness is preferably 150 μm or less, particularly preferably 120 μm or less, further preferably 110 μm or less. By setting the thickness of the support sheet 11 within the above range, the support sheet 11 tends to have required mechanical strength, and the aforementioned adherend processability and the like become favorable.

The adhesive film 2 with a support sheet may be a dicing die used in the manufacture of a semiconductor device. The adhesive film 2 with a support sheet at this time can be used in the process of dicing semiconductor elements and the process of die bonding, and the cured product of the adhesive film can be used as a heat release device for driving the semiconductor device. It functions against the external heat-conducting material. The support sheet 11 in this case is preferably, for example, a support sheet in which a known adhesive layer is provided on the surface of the above-mentioned resin film on the side of the adhesive film 1 .

As a production example of the adhesive film 2 with a support sheet, the release sheet can be peeled off from the above-mentioned laminate composed of the release sheet/adhesive film/protective film and the support sheet can be laminated, or the above-mentioned release sheet/adhesive film can be made of The protective film is peeled off and the support sheet is laminated on the laminated body which consists of a composite film/protective film, and a support sheet can also be used instead of a protective film in the manufacturing method of the said adhesive film.

[cured body]

The cured product according to one embodiment of the present invention is a cured product obtained by curing the above-mentioned adhesive film by heat treatment, preferably a cured product obtained by curing the above-mentioned hot-pressed adhesive film by heat treatment.

1. Physical properties

(1) Area ratio of the void portion

The area ratio of voids in the cross-section in the thickness direction of the cured body in this embodiment is preferably 10% or less, more preferably 7% or less, particularly preferably 5% or less, further preferably 4% or less. By setting the area ratio of the voids to 10% or less, the thermally conductive fillers (A) are further in contact with each other, thereby forming heat conduction paths with high density, and further improving thermal conductivity. The lower limit of the above area ratio is not particularly limited, but is most preferably 0%. In addition, the derivation method of the area ratio of the said void part is shown in the test example mentioned later.

(2) The maximum area of the void portion

The maximum area of voids in the cross section in the thickness direction of the cured body in this embodiment is preferably 100 μm ^or less, more preferably 80 μm ^or less, particularly preferably 60 μm ^or less, further preferably 50 μm ^or less. By setting the area ratio of the voids to 100 μm ² or less, the thermally conductive fillers (A) are further brought into contact with each other, thereby forming heat conduction paths at high density, and further improving thermal conductivity. The lower limit of the maximum area is not particularly limited, but is most preferably 0 μm ² . In addition, the derivation method of the maximum area of the said void part is shown in the test example mentioned later.

(3) thermal conductivity

The thermal conductivity of the cured body in this embodiment is preferably 4 W/mK or higher, particularly preferably 5 W/mK or higher. From this, it can be said that the cured body is excellent in thermal conductivity. Such a high thermal conductivity can be realized by making the adhesive film of the cured body of this embodiment have the above-mentioned configuration. In addition, the measuring method of the thermal conductivity in this specification is as shown in the test example mentioned later.

2. Manufacturing method of cured body

In order to produce the cured body of this embodiment, the adhesive film (preferably, the adhesive film after hot pressing) is heat-treated to finally be completely cured.

The above heat treatment preferably includes a preheating step and a complete curing step for completely curing the adhesive film after the preheating step, and the preheating step is at a temperature below the following temperature (hereinafter sometimes referred to as "preheating temperature"). ") for more than 30 minutes, the temperature is: under the condition of increasing the temperature from 40°C to 400°C at a temperature increase rate of 10°C/min in the air atmosphere, the above-mentioned The temperature at which the weight of an adhesive film decreases by 0.5% when subjected to a thermogravimetric test. If the adhesive film is completely cured by rapid heat treatment, the low-molecular components in the adhesive film will volatilize and foam due to heating, and voids will easily be generated inside the adhesive film. In this regard, if the heat treatment includes the above steps, the low-molecular components are captured and trapped in the matrix of the thermosetting component (B), binder polymer (C), etc. reduce. Through the above-mentioned preheating step (and the above-mentioned hot pressing), the area ratio and the maximum area of the above-mentioned voids are set to preferable values, and the thermal conductivity of the cured product becomes more excellent.

The above-mentioned preheating temperature is preferably 1 to 50°C lower than the temperature at which the weight of the adhesive film is reduced by 0.5%, particularly preferably 10 to 40°C, and more preferably 15 to 30°C lower. In addition, the lower limit of the preheating temperature is preferably 80°C or higher, particularly preferably 90°C or higher, and further preferably 100°C or higher.

In addition, the above-mentioned preheating step is preferably performed for 30 minutes, particularly preferably for 30 to 120 minutes, and even more preferably for 30 to 60 minutes.

In the above-mentioned heat treatment, it is preferable to perform a complete curing step at a heating temperature for completely curing the adhesive film after the above-mentioned preheating step. The heating temperature in the complete curing step needs to be higher than the above preheating temperature, preferably 5 to 100°C higher than the preheating temperature, particularly preferably 10 to 70°C higher, more preferably 20 to 50°C higher. The heating temperature in the complete curing step is specifically preferably 85 to 200°C, particularly preferably 100 to 190°C, further preferably 120 to 180°C.

In addition, the above-mentioned complete curing step is preferably performed for 30 to 180 minutes, particularly preferably for 45 to 150 minutes, and even more preferably for 60 to 120 minutes.

The cured body of this embodiment may exist as a single body, but usually exists in a state of being in contact with one or two or more members to conduct heat conduction.

[structure]

A structure according to one embodiment of the present invention is formed by combining at least a part of the first member and at least a part of the second member through the above-mentioned cured body.

A structure as an example of this embodiment is shown in FIG. 2 . The structure 3 shown in FIG. 2 includes a first member 31 , a second member 32 , and a cured body 1A provided between the first member 31 and the second member 32 .

The cured body 1A is a cured product obtained by completely curing the above-mentioned adhesive film (adhesive film 1 ; including an adhesive film not subjected to heat pressing and an adhesive film subjected to heat pressing) by the heat treatment described above. The first member 31 and the second member 32 are fixed to each other by the adhesiveness of the cured body 1A (adhesive film). The shapes of the first member 31 and the second member 32 in this embodiment are not particularly limited, and may be a flexible sheet, a plate, or a block.

The first member 31 (or second member 32) in this embodiment is not particularly limited, but for example, it is preferably a member that generates heat as it performs a predetermined function but needs to suppress a temperature rise, or a member that requires the heat generated by the member. A component (heat generating component) that controls the flow in a specific direction, etc. Also, the second member 32 (or the first member 31 ) is not particularly limited, but is preferably a member that dissipates heat received or a member that conducts heat received to another member (heat transfer member). The cured body 1A in this embodiment has excellent thermal conductivity, and therefore can function as a heat-conducting material that conducts heat from the first member 31 that generates heat to the second member 32 and releases the heat to the outside, for example.

Examples of heat generating components include semiconductor devices such as thermoelectric conversion devices, photoelectric conversion devices, and large-scale integrated circuits, electronic devices such as LED light emitting elements, optical pickups, and power transistors, and various electronic devices such as mobile terminals and wearable terminals. , battery (battery), battery, motor, engine, etc. In addition, the heat transfer member is preferably made of metal such as aluminum, stainless steel, and copper, or a highly conductive material such as graphite or carbon nanofiber. The form of the heat transfer member may be any of a substrate, a frame, a heat sink, a heat sink, and the like, and is not particularly limited.

In order to manufacture the structure 3 of the present embodiment, one side of the above-mentioned adhesive film is attached to the first member 31 (or the second member 32), and then the other side of the adhesive film is attached to the second member. 32 (or first member 31). When using the above-mentioned adhesive film 2 with a support sheet, the release sheet 12 is peeled off, one side of the exposed adhesive film 1 is attached to the first member 31 (or second member 32), and then the support sheet 11 is peeled off. What is necessary is just to stick the other surface of the adhesive film 1 exposed to the 2nd member 32 (or the 1st member 31).

As the adhesive film used to manufacture the structure 3 of the present embodiment, any of an adhesive film that has not been hot-pressed and an adhesive film that has been hot-pressed can be used, but one that has been hot-pressed is preferably used. Adhesive film. In addition, using an adhesive film that has not been subjected to heat pressing, it is possible to attach the adhesive film to the first member 31 (or the second member 32 ), or connect the first member 31 and the second member 32 via the adhesive film. After bonding, heat press the adhesive film. However, if an adhesive film previously subjected to heat pressing is used, it is possible to prevent damage to the first member 31 and/or the second member 32 due to heat pressing.

Among them, when the first member 31 and the second member 32 are bonded via an adhesive film, or when the adhesive film is attached to the first member 31 or the second member 32, it is preferable that the above-mentioned adhesive layer before any heat treatment is performed. At a temperature (hereinafter sometimes referred to as "tan δ peak temperature") showing the peak of loss tangent (tan δ) obtained in the viscoelasticity measurement of the composite film (hereinafter sometimes referred to as "sticking treatment temperature") or higher, The above-mentioned pasting or sticking is carried out. By sticking or sticking at such a temperature, the adhesive film will become soft, and air can be more effectively suppressed from being entrapped between it and the adherend, and the contact between the adhesive film and the adherend can be made Excellent thermal conductivity. In addition, the measuring method of the viscoelasticity of an adhesive film is as shown in the test example mentioned later.

The first member 31 is a flexible sheet-like member. When a laminate of the sheet-like member and the adhesive film is attached to the second member 32, or when the adhesive film 2 with a supporting sheet is attached to the first member 31 or the second member 32, the above-mentioned effect of suppressing entrainment of air becomes more excellent. This is because the laminate of the sheet-like member and the adhesive film, or the adhesive film 2 with the support sheet, is soft and flexible, so it can be gradually adhered to the adherend from one direction to the other, thereby enabling the Squeeze out the air while attaching.

The attachment treatment temperature is preferably 0 to 50°C higher than the tan δ peak temperature, particularly preferably 2 to 30°C higher, and more preferably 5 to 20°C higher. In addition, the upper limit of the sticking treatment temperature needs to be lower than the curing temperature of the adhesive film, specifically, it is preferably 120°C or lower, particularly preferably 100°C or lower, and more preferably 90°C or lower.

As described above, one side of the first adhesive film is attached to the first member 31 (or the second member 32), and the other side of the adhesive film is attached to the second member 32 (or the first member 31) Afterwards, the heat treatment for producing the above-mentioned cured body of the adhesive film is performed to completely cure the adhesive film to form a cured body 1A, thereby obtaining the structured body 3 of the present embodiment.

The embodiments described above are described for easy understanding of the present invention, and are not described for limiting the present invention. Therefore, each requirement disclosed in the above-mentioned embodiments also covers all design changes or equivalents falling within the technical scope of the present invention.

For example, the release sheet 12 laminated on the adhesive film 1 in FIG. 1 may be omitted. In addition, the shapes of the first member and the first member in the structure are not limited to those shown in FIG. 2 , and may be in various shapes.

[Example]

Hereinafter, although an Example etc. demonstrate this invention more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]

A mixture in which the following components (a) and (c) were mixed and diluted with methyl ethyl ketone to a solid content concentration of 15% by mass was stirred with a disperser at 3000 rpm for 30 minutes or more to dissolve and disperse. The following components (b-1), (b-2), (d-1), (d-2) and (e) are added thereto, and methyl ethyl ketone is further added to the solid content of the whole The concentration was 21% by mass. This mixed solution was stirred for 10 minutes with an autorotation/revolution mixer (manufactured by THINKY CORPORATION, product name "AR-100") to obtain a coating solution of an adhesive resin composition.

The content (in terms of solid content) of each component in this adhesive resin composition is 30.01 mass % for (a) component, 34.95 mass % for (c) component, 16.56 mass % for (b-1) component, ( 7.23 mass % of b-2 components, 5.61 mass % of (d-1) components, 5.61 mass % of (d-2) components, and 0.03 mass % of (e) components.

(a) Thermally conductive filler: Graphene (manufactured by ADEKA CORPORATION, product name

"CNS-1A1", average particle size 12μm, thickness 50nm or less, Raman peak intensity ratio D/G=0.1, when measured by X-ray diffraction method using CuKα ray source (wavelength 0.15418nm), the 2θ is 26.6° and 42.4 The peak is detected at the position of °)

(b-1) thermosetting component: an epoxy resin having a naphthalene skeleton represented by the following formula (1) dissolved in methyl ethyl ketone (manufactured by Nippon Kayaku Co., Ltd., product name "NC-7000L", Epoxy equivalent of 223 to 238 g/eq, ICI viscosity (150° C.) of 0.50 to 1.00 Pa·s, softening point of 83 to 93° C.) (solid content concentration: 70% by mass).

[chemical formula 4]

In the formula, n is an integer of 0 or more.

(b-2) Thermosetting component: bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "YL983U", epoxy equivalent 165-175g/eq, viscosity (25°C) 3.0-6.0Pa·s)

(c) Binder polymer: an acrylate polymer (manufactured by Mitsubishi Chemical Corporation, product name "COPONYL N-4617") was dissolved in a 1:1 mixed solvent of ethyl acetate and toluene to make 85 parts by mass of methyl acrylate and Copolymer obtained by copolymerizing 15 parts by mass of 2-hydroxyethyl acrylate, weight average molecular weight: 300,000, glass transition temperature: 6°C) (solid content concentration: 36% by mass)

(d-1) Curing agent: Dissolve novolac type phenolic resin (manufactured by ASAHI YUKIZAI CORPORATION, product name "PAPS-PN4" with methyl ethyl ketone, hydroxyl equivalent 104g/eq, ICI viscosity (150°C) 3.0Pa·s, Softening point 111°C) obtained (solid content concentration 60% by mass)

(d-2) Curing agent: Dissolve a biphenyl phenol compound represented by the following formula (3) in methyl ethyl ketone (manufactured by Honshu Chemical Industry Co., Ltd., product name "BP", hydroxyl equivalent 93.1 g/eq , sublimation temperature 283°C) obtained (solid content concentration 10% by mass)

[chemical formula 5]

(e) Curing accelerator: 2-phenyl-4,5-hydroxymethylimidazole

The coating solution of the adhesive resin composition obtained in the above steps was applied with an applicator to a peeling sheet that had been peeled off on one side of a polyethylene terephthalate film with a silicone-based peeling agent ( Manufactured by LINTEC Corporation, product name "SP-PET3811(S)", arithmetic mean roughness (Ra) of the peeled surface: 0.002 μm), heat treatment at 100°C for 2 minutes to dry, and form a sticky Composite film (thickness: 50 μm). Then, on the release-treated surface of a protective film (manufactured by LINTEC Corporation, product name "SP-PET3811(S)") that has been peeled off from one side of the polyethylene terephthalate film with a silicone-based release agent, , the adhesive film with the release sheet was bonded together to obtain a laminate composed of the release sheet, the adhesive film (thickness: 50 μm), and the protective film.

The laminate obtained above was cut into 4 cm x 4 cm, and a pressure of 3.0 MPa was applied to the laminate at 50° C. for 30 minutes using a spiral hot press device to heat press the adhesive film.

[Example 2]

In the hot pressing, an adhesive film was produced in the same manner as in Example 1 (after hot pressing) except that the applied pressure of the screw hot pressing device was 2.5 MPa.

[Example 3]

In Test Example 4 described later, the temperature at which the hot-pressed adhesive film of Example 1 was bonded to the silicon wafer was 75° C., and this was referred to as Example 3.

[Comparative example 1]

In Test Example 6 described later, the hot-pressed adhesive film of Example 1 was heat-treated at 175° C. for 3 hours (complete curing step) without performing a preheating step, and this was referred to as Comparative Example 1.

[Comparative example 2]

In hot pressing, an adhesive film was produced in the same manner as in Example 1 except that the applied pressure of the spiral hot pressing device was 0 MPa (for convenience, it is also called "adhesive film after hot pressing") .

[Comparative example 3]

As the (a) thermally conductive filler, spherical alumina particles (manufactured by Showa Denko KK, product name "CB-P05J", average particle diameter 5.0 μm, aspect ratio: 1.1, specific gravity: 3.98 g/cm were used ³ ) Instead of graphene in Example 1, an adhesive film was produced in the same manner as in Example 1 except that.

[Comparative example 4]

Spherical alumina particles (manufactured by Showa Denko KK, product name "CB-P05J", average particle diameter: 5.0 μm, aspect ratio: 1.1, specific gravity: 3.98 g/ cm ³ ) was changed to 81.4% by mass, and an adhesive film was produced in the same manner as in Comparative Example 3.

[Comparative Example 5]

In Test Example 6 described later, the hot-pressed adhesive film of Comparative Example 3 was heat-treated at 175° C. for 3 hours (complete curing step) without preheating, and this was referred to as Comparative Example 5.

[Comparative Example 6]

In Test Example 4 described later, the temperature at which the hot-pressed adhesive film of Comparative Example 3 was attached to the silicon wafer was set to room temperature (R.T.), and this was referred to as Comparative Example 6.

[Test Example 1] <Thermogravimetric test (TG test)>

For the adhesive film before hot pressing obtained in each Example and Comparative Example, using a thermal analysis measuring device (manufactured by SHIMADZU CORPORATION, thermal analyzer TG/DTA simultaneous measuring device, product name "DTG-60"), with Measure approximately the same amount of alumina particles as a reference sample, and conduct a thermogravimetric test from 40°C to 400°C at a heating rate of 10°C/min in the air atmosphere to obtain the temperature at which the weight loss is 0.5%. As a result, for the adhesive films before hot pressing obtained in Examples 1 to 3 and Comparative Examples 1 to 3, and 5 to 6, the above-mentioned temperature was 147° C., and for the adhesive film before hot pressing obtained in Comparative Example 4, the above temperature was 147° C. It is 151°C.

[Test Example 2] <Measurement of Dynamic Viscoelasticity>

The adhesive films before hot pressing obtained in each of the Examples and Comparative Examples were laminated so as to have a thickness of 0.2 mm, and cut into a size of 20 mm×10 mm to obtain samples for measurement. The obtained sample was installed in a dynamic viscoelasticity measuring device (manufactured by TA Instrument, product name "DMA-Q800") with a measurement length of 10 mm (distance between clamps), at a frequency of 11 Hz, an amplitude of 5 μm, and a heating rate of 3 ° C / Under the condition of min, measure the loss tangent (tan δ) in the temperature range of 25 to 100°C, and find the temperature at which the loss tangent (tan δ) reaches the maximum within the measured temperature range. As a result, for the adhesive films before hot pressing obtained in Examples 1-3 and Comparative Examples 1-2, the above-mentioned temperature was 73° C., and for the adhesive films before hot pressing obtained in Comparative Examples 3 and 5-6, the above-mentioned The temperature was 71°C, and for the adhesive film obtained in Comparative Example 4 before hot pressing, the temperature was 75°C.

[Test Example 3] <Measurement of Arithmetic Mean Roughness (Ra)>

(1) The release surface of the release sheet

For the surface roughness of the release-treated surface of the release sheet used in each Example and Comparative Example, using a scanning probe microscope (SPM) device (manufactured by Hitachi High-Tech Science Corporation, product name "SPA-300HV"), measured by DFM Mode, measure the surface of the sample within the range of 5 μm × 5 μm, and determine the arithmetic mean roughness (Ra). In addition, "OMCL-AC240TS-C3" (resonance frequency; 55-65 kHz, spring constant; about 2 N/m ² ) manufactured by Olympus Corporation was used for the cantilever. As a result, the arithmetic mean roughness (Ra) of the release-treated surface of the release sheet was 0.002 μm.

(2) The surface of the adhesive film

The surface roughness of the hot-pressed adhesive film surface (the surface in contact with the release-treated surface of the release sheet) obtained in each of the Examples and Comparative Examples was measured using a shape laser microscope (manufactured by KEYENCE CORPORATION, product name "Three-Dimensional Laser Microscope VK-9700"), according to JIS B0601:2001, with a cut-off value of 2.5mm, measuring in the range of 700×500μm ² to determine the arithmetic mean roughness (Ra). The results are shown in Table 1.

[Test Example 4] <Adhesive force measurement>

The coating liquid of the adhesive resin composition obtained in each Example and Comparative Example was coated on one side of a polyethylene terephthalate film with a thickness of 12 μm, and heat-treated at 100° C. for 2 minutes to make it It dried and produced the laminated body in which the adhesive film (thickness: 50 micrometers) adhered firmly to the polyethylene terephthalate film.

Next, for the purpose of protecting the surface of the adhesive film, a release-treated surface of a release film (manufactured by LINTEC Corporation, product name "SP-PET381031", thickness 38 μm) was attached to the adhesive film-side surface of the laminate. The obtained laminate was cut into 4 cm x 4 cm together with the release film, and hot-pressed under the conditions of each Example. Then, this was cut together with a release film to obtain an adhesive force measurement sample having a width of 25 mm and a length of 40 mm.

A silicon wafer (manufactured by Science & Technology Inst., Co., diameter: 150 mm, thickness: 500 μm) whose surface was chemically mechanically polished so that the arithmetic average roughness (Ra) was 0.02 μm or less was prepared separately as an adherend . The release film of the sample for measuring adhesion was peeled off, and the exposed surface of the adhesive film was attached to the treated surface of the silicon wafer to obtain a laminate composed of the silicon wafer and the sample for measuring adhesion. The temperature at the time of this sticking was 80° C. (Examples 1 to 2, Comparative Examples 1 to 5), 75° C. (Example 3), or room temperature (Comparative Example 6).

After leaving the obtained laminated body at 23° C. and an atmosphere with a relative humidity of 50% for 20 minutes, use a universal tensile testing machine (manufactured by INSTRON CORPORATION, product name “5581 testing machine”), according to JIS Z0237:2000, with The peeling speed was 300mm/min for 180°peeling test. The load at the time of this 180° peeling was measured, and this measured value was made into adhesive force (N/25mm).

The results are shown in Table 1.

(Test Example 5) <Temporary Adhesive Evaluation>

The laminate obtained in Test Example 4 was observed, and temporary adhesiveness was evaluated according to the following criteria.

The results are shown in Table 1.

◯: The sample for adhesive force measurement was attached to the adherend, and air was not entrapped at the interface.

Δ: The sample for adhesive force measurement was attached to the adherend, and the entrapment of air at the interface was confirmed.

╳: The sample for adhesive force measurement was not attached to the adherend.

[Test Example 6] <Evaluation of Void Portion in Cross Section of Cured Body>

1. The area ratio of the void part

The hot-pressed laminates obtained in Examples 1 to 3 and Comparative Examples 2 to 4 and 6 were heat-treated at 125°C for 1 hour (preheating step), followed by heat treatment at 175°C for 2 hours (complete curing step), The heat-pressed adhesive film is completely cured to form a cured body. On the other hand, in Comparative Examples 1 and 5, heat treatment at 175° C. for 3 hours (complete curing step) was performed without performing the preheating step, and the hot-pressed adhesive film was completely cured to form a cured body.

For the cross-section of the cured body of the above-mentioned adhesive film, use a sputtering device (VACUUM DEVICE, product name "MSP-20-UM Magnetron Spatter"), using Pt-Pd as a target, coat a film with a thickness of about 30 nm, and perform anti-corrosion. Electrostatic treatment. Six images of the cross-section of the above cured body were taken using a scanning electron microscope (SEM) device (manufactured by KEYENCE CORPORATION, product name "VE-9800"). The imaging conditions were an acceleration voltage of 8 kV and a magnification of 1000 times. One of the SEM images (cured body of the adhesive film of Example 1) is shown in FIG. 3 .

Binarize the void part and other parts of the obtained 6 SEM images. In the binarization, the brightness threshold was set to 77-110 using image analysis software (ImageJ). FIG. 4 shows the binarized SEM image of the cross-section of the cured body of the adhesive film of Example 1 shown in FIG. 3 . The black part in the figure is the void part. Using the binarized image, the total area of the voids was divided by the area of the entire cross-section of the adhesive film obtained from the SEM image, and the area ratio of the voids was obtained from the average value of six SEM images. The results are shown in Table 1.

In addition, since the brightness threshold value differs depending on the condition setting at the time of SEM image observation, its value is determined while comparing it with the actual SEM observation image. In addition, regarding the binarized image, compared with the original SEM image, the portion that does not belong to the void portion is appropriately removed.

For reference, the SEM image of the cross section of the hardened body of the adhesive film of Comparative Example 2 is shown in FIG. 5 . In addition, an image obtained by binarizing the SEM image shown in FIG. 5 is shown in FIG. 6 in the same manner as above.

2. The maximum area of the void

Using the binarized images of the above six SEM images, the maximum value of the area of the continuous voids was obtained, and this was defined as the maximum area (μm ² ) of the voids. The results are shown in Table 1.

[Test Example 7] <Measurement Evaluation of Thermal Diffusivity>

The cured body of the adhesive film obtained in Test Example 6 was cut to obtain a square sample with each side being 5 mm. The thermal diffusivity of the cured body of the above-mentioned adhesive film was measured using a thermal conductivity measuring device (manufactured by Aiphase Corporation, product name "aiphase.mobile 1u"). Then, the specific gravity and the specific heat were multiplied by the thermal diffusivity to calculate the thermal conductivity (W/mK) of the cured product of the adhesive film. The results are shown in Table 1.

As can be seen from Table 1, the cured products of the adhesive films produced in Examples 1 to 3 have excellent thermal conductivity. In addition, the adhesive films in Examples 1 to 3 were also excellent in temporary adhesiveness.

Industrial Applicability

The adhesive film and cured product of the present invention can be suitably used, for example, to be sandwiched between a heat-generating electronic device and a heat-dissipating substrate or heat sink to cool the electronic device. In addition, the structure of the present invention is useful, for example, as a structure including a heat-generating electronic device and a heat-dissipating substrate or heat sink.

Explanation of reference signs

1: Adhesive film; 11: Support sheet; 12: Release sheet; 2: Adhesive film with support sheet; 3: Structure; 1A: Cured body of adhesive film; 31: First member; 32: Second member.

Claims (21)

1. An adhesive film comprising an adhesive resin composition, the adhesive resin composition comprising:

a thermally conductive filler (A) composed of at least 1 of graphene having a two-dimensional structure and a single layer of boron nitride;

a thermosetting component (B); and

A binder polymer (C),

the adhesive film is used in such a manner that the following heat treatment is performed,

the heat treatment includes a preheating step, and a complete curing step of completely curing the adhesive film after the preheating step,

the preheating step is a step of maintaining the temperature at a temperature of not higher than the following temperature (T) for 30 minutes or more,

temperature (T): and a temperature at which the weight of the adhesive film is reduced by 0.5% when the adhesive film before any heat treatment is subjected to a thermogravimetric test under an atmosphere and under a condition of a temperature rise from 40 ℃ to 400 ℃ at a temperature rise rate of 10 ℃/minute.

2. An adhesive film comprising an adhesive resin composition, the adhesive resin composition comprising:

a thermally conductive filler (A) composed of at least 1 of graphene having a two-dimensional structure and a single layer of boron nitride;

a thermosetting component (B); and

A binder polymer (C),

the area ratio of the void portion in the cross section in the thickness direction of the cured product obtained by heat-treating the adhesive film under the following conditions is 10% or less,

conditions are as follows: the heat treatment includes a preheating step, and a complete curing step of completely curing the adhesive film after the preheating step,

the preheating step is a step of maintaining at a temperature of at most the following temperature for 30 minutes or more: and a temperature at which the weight of the adhesive film is reduced by 0.5% when the adhesive film before any heat treatment is subjected to a thermogravimetric test under an atmosphere and under a condition of a temperature rise from 40 ℃ to 400 ℃ at a temperature rise rate of 10 ℃/minute.

3. The adhesive film according to claim 1 or 2, wherein the content of the thermally conductive filler (a) is 5 mass% or more and 60 mass% or less.

4. An adhesive film according to any one of claims 1 to 3, wherein the thermosetting component (B) is an epoxy resin.

5. The adhesive film according to any one of claims 1 to 4, wherein the adhesive film is formed by performing hot pressing.

6. The adhesive film according to any one of claims 1 to 5, wherein at least one surface thereof has an arithmetic average roughness (Ra) of 0.01 μm or more and 0.5 μm or less.

7. A method for producing an adhesive film, characterized by comprising the steps of,

mixing a thermally conductive filler (A) composed of at least 1 of graphene having a two-dimensional structure and a single layer of boron nitride with a binder polymer (C) in a solvent, and then further mixing a thermosetting component (B), thereby obtaining an adhesive resin composition,

the adhesive resin composition obtained is formed into a film shape.

8. The method of producing an adhesive film according to claim 7, wherein the adhesive resin composition is formed into a film shape and then further subjected to hot pressing.

9. The method of producing an adhesive film according to claim 8, wherein the heating temperature of the hot press is less than the curing reaction temperature of the thermosetting component (B).

10. The method of producing an adhesive film according to claim 8 or 9, wherein an arithmetic average roughness (Ra) of at least one surface of the adhesive film after hot pressing is 0.01 μm or more and 0.5 μm or less.

11. An adhesive film with a support sheet, comprising:

the adhesive film of any one of claims 1 to 6; and

And a support sheet laminated on at least one surface side of the adhesive film.

12. A cured body obtained by heat-treating an adhesive film comprising an adhesive resin composition containing:

A thermally conductive filler (A) composed of at least 1 of graphene having a two-dimensional structure and a single layer of boron nitride;

a thermosetting component (B); and

A binder polymer (C),

the area ratio of the void portion in the cross section in the thickness direction of the cured body is 10% or less.

13. The cured product according to claim 12, wherein the maximum area of the void portion of the cross section in the thickness direction of the cured product is 100 μm ² The following is given.

14. The cured body according to claim 12 or 13, wherein the heat treatment comprises a preheating step and a complete curing step of completely curing the adhesive film after the preheating step,

the preheating step includes a step of maintaining at a temperature of at most the following temperature for 30 minutes or more: and a temperature at which the weight of the adhesive film is reduced by 0.5% when the adhesive film before any heat treatment is subjected to a thermogravimetric test under an atmosphere and under a condition of a temperature rise from 40 ℃ to 400 ℃ at a temperature rise rate of 10 ℃/minute.

15. A method for producing a cured body, characterized in that a cured body is produced by heat-treating an adhesive film comprising an adhesive resin composition comprising:

A thermally conductive filler (A) composed of at least 1 of graphene having a two-dimensional structure and a single layer of boron nitride;

a thermosetting component (B); and

A binder polymer (C),

the heat treatment includes a preheating step, and a complete curing step of completely curing the adhesive film after the preheating step,

the preheating step includes a step of maintaining at a temperature of at most the following temperature for 30 minutes or more: and a temperature at which the weight of the adhesive film is reduced by 0.5% when the adhesive film before any heat treatment is subjected to a thermogravimetric test under an atmosphere and under a condition of a temperature rise from 40 ℃ to 400 ℃ at a temperature rise rate of 10 ℃/minute.

16. The method of producing a cured product according to claim 15, wherein the adhesive film is hot-pressed before the heat treatment.

17. The method of producing a cured body according to claim 15 or 16, wherein the area ratio of the void portion in the cross section in the thickness direction of the cured body is 10% or less.

18. A method for manufacturing a structure, the method comprising:

a bonding step of bonding at least a part of a first member to at least a part of a second member via an adhesive film composed of an adhesive resin composition containing: a thermally conductive filler (A) composed of at least 1 of graphene having a two-dimensional structure and single-layer boron nitride, a thermosetting component (B), and a binder polymer (C); and

A step of heating the adhesive film to form a cured product after the bonding, thereby obtaining a structure in which at least a part of the first member and at least a part of the second member are bonded together via the cured product,

the heat treatment includes a preheating step, and a complete curing step of completely curing the adhesive film after the preheating step,

the preheating step includes a step of maintaining at a temperature of at most the following temperature for 30 minutes or more: and a temperature at which the weight of the adhesive film is reduced by 0.5% when the adhesive film before any heat treatment is subjected to a thermogravimetric test under an atmosphere and under a condition of a temperature rise from 40 ℃ to 400 ℃ at a temperature rise rate of 10 ℃/minute.

19. The method for manufacturing a structure according to claim 15, wherein the adhesive film is hot-pressed before the heat treatment.

20. The method of manufacturing a structure according to claim 18 or 19, wherein an area ratio of a void portion of a cross section in a thickness direction of the cured body is 10% or less.

21. The method according to any one of claims 18 to 20, wherein in the bonding step, the bonding is performed at a temperature equal to or higher than a temperature at which a peak of loss tangent (tan δ) is displayed, the peak being obtained in the viscoelastic measurement of the adhesive film before the optional heat treatment.

Images