JP2023154941A - Thermosetting resin composition, resin sheet, resin substrate, and circuit board - Google Patents

Abstract

To provide a thermosetting resin composition that can be used to produce a thermally conductive sheet with high thermal conductivity.SOLUTION: A thermosetting resin composition includes an epoxy resin expressed by the formula (1) and a curing agent, where n represents the number of repetitions of the structure within the parentheses, which is an integer of 1 or greater, Y represents a group expressed by the formula (ep), A represents a divalent group with a mesogenic skeleton, and B represents -(CH2)p- or -O-(CH2)q-O-, where p and q each represent an integer of 2-6, and r represents an integer of 1-3.SELECTED DRAWING: None

Description

The present invention relates to a thermosetting resin composition, a resin sheet made of the thermosetting resin composition, a resin substrate made of a cured product of the resin sheet, and a circuit board equipped with the cured product of the resin sheet.

With the increasing integration of semiconductors and the rapid improvement in the processing power of electronic devices, a large amount of heat is generated from electronic components with high processing power. Therefore, heat countermeasures that effectively dissipate heat from electronic components to the outside have become an extremely important issue. As a heat dissipation measure, heat dissipation materials such as printed wiring boards, semiconductor packages, housings, heat pipes, heat sinks, and heat diffusion plates are made of thermally conductive materials such as metals, ceramics, and polymer compositions. member is applied.

Among these heat dissipation members, thermally conductive epoxy resin molded bodies made from epoxy resin compositions have excellent electrical insulation, mechanical properties, heat resistance, chemical resistance, adhesive properties, etc., and are therefore suitable for casting. It is widely used mainly in the electrical and electronic fields as products, laminates, sealants, thermally conductive sheets, adhesives, etc.

As this type of technology, for example, Patent Document 1 describes a thermally conductive epoxy resin composition in which scale-shaped or spherical boron nitride particles are blended as thermally conductive particles into a bisphenol A epoxy resin as an epoxy resin; A molded article thereof has been proposed. It has also been proposed to improve the thermal conductivity and heat resistance of the epoxy resin itself (for example, Patent Document 2). In Patent Document 2, an insulating composition with improved thermal conductivity is obtained by polymerizing a liquid crystalline epoxy resin or the like having a mesogenic group.

Japanese Patent Application Publication No. 2015-193504 Patent Application No. 2004-331811

However, as a result of studies conducted by the present inventors, it has been found that the conventional resin compositions have room for further improvement in terms of thermal conductivity.

The present invention was made in view of the above problems, and the present invention was completed by discovering that an epoxy resin having a specific mesogen skeleton has high thermal conductivity.

式（１）中、
ｎは、括弧内の構造の繰り返し数を表し、１以上の整数であり、
Ｙは、式（ｅｐ）で表される基であり、
Ａは、メソゲン骨格を有する２価の基であり、
Ｂは、－（ＣＨ_２）_ｐ－、または－Ｏ－（ＣＨ_２）_ｑ－Ｏ－であり、ここで、ｐおよびｑは、２～６の整数であり、

式（ｅｐ）中、ｒは、１～３の整数である、
熱硬化性樹脂組成物。
［２］前記メソゲン骨格を有する２価の基は、式（１－１）、式（１－２）、または式（１－３）で表される基から選択される基であり、

式（１－１）中、Ｒ^１～Ｒ^８は、各々独立して、水素原子、または炭素数１～３のアルキル基であり、＊は、連結部位を表し、

式（１－２）中、Ｒ^１～Ｒ^８は、各々独立して、水素原子、または炭素数１～３のアルキル基であり、＊は、連結部位を表し、

式（１－３）中、Ｒ^１～Ｒ^８は、各々独立して、水素原子、または炭素数１～３のアルキル基であり、＊は、連結部位を表す、項目［１］に記載の熱硬化性樹脂組成物。
［３］前記式（１）中のｎが１である、項目［１］または［２］に記載の熱硬化性樹脂組成物。
［４］前記硬化剤は、フェノール樹脂、アミン化合物、活性エステル化合物、酸無水物、およびシアネート化合物から選択される少なくとも１つである、項目［１］～［３］のいずれかに記載の熱硬化性樹脂組成物。
［５］硬化促進剤をさらに含む、項目［１］～［４］のいずれかに記載の熱硬化性樹脂組成物。
［６］前記硬化促進剤は、イミダゾール化合物、ホスフィン化合物、およびフェノール化合物から選択される少なくとも１つである、項目［５］に記載の熱硬化性樹脂組成物。
［７］熱伝導性フィラーをさらに含む、項目［１］～［６］のいずれかに記載の熱硬化性樹脂組成物。
［８］溶剤をさらに含む、項目［１］～［７］のいずれかに記載の熱硬化性樹脂組成物。
［９］項目［１］～［８］のいずれかに記載の熱硬化性樹脂組成物をフィルム状に形成して得られる樹脂シート。
［１０］項目［１］～［８］のいずれかに記載の熱硬化性樹脂組成物の硬化物からなる樹脂基板。
［１１］金属層と、
前記金属層の少なくとも一方の面に積層された樹脂層と、を備え、
前記樹脂層は、項目［１］～［８］のいずれかに記載の熱硬化性樹脂組成物の硬化物からなる、回路基板。 According to the present invention, there are provided the following thermosetting resin composition, as well as resin sheets, resin substrates, and circuit boards obtained using the same.
[1] An epoxy resin represented by formula (1),
A thermosetting resin composition comprising a curing agent,

In formula (1),
n represents the number of repetitions of the structure in parentheses, and is an integer of 1 or more,
Y is a group represented by formula (ep),
A is a divalent group having a mesogenic skeleton,
B is -(CH ₂ ) _p - or -O-(CH ₂ ) _q -O-, where p and q are integers from 2 to 6,

In the formula (ep), r is an integer from 1 to 3,
Thermosetting resin composition.
[2] The divalent group having a mesogenic skeleton is a group selected from a group represented by formula (1-1), formula (1-2), or formula (1-3),

In formula (1-1), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, * represents a linking site,

In formula (1-2), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, * represents a linking site,

In formula (1-3), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and * represents a linking site, as described in item [1] Thermosetting resin composition.
[3] The thermosetting resin composition according to item [1] or [2], wherein n in the formula (1) is 1.
[4] The curing agent according to any one of items [1] to [3], wherein the curing agent is at least one selected from a phenolic resin, an amine compound, an active ester compound, an acid anhydride, and a cyanate compound. Curable resin composition.
[5] The thermosetting resin composition according to any one of items [1] to [4], further comprising a curing accelerator.
[6] The thermosetting resin composition according to item [5], wherein the curing accelerator is at least one selected from an imidazole compound, a phosphine compound, and a phenol compound.
[7] The thermosetting resin composition according to any one of items [1] to [6], further comprising a thermally conductive filler.
[8] The thermosetting resin composition according to any one of items [1] to [7], further comprising a solvent.
[9] A resin sheet obtained by forming the thermosetting resin composition according to any one of items [1] to [8] into a film.
[10] A resin substrate comprising a cured product of the thermosetting resin composition according to any one of items [1] to [8].
[11] Metal layer;
a resin layer laminated on at least one surface of the metal layer,
The circuit board, wherein the resin layer is made of a cured product of the thermosetting resin composition according to any one of items [1] to [8].

According to the present invention, a thermosetting resin composition whose cured product has high thermal conductivity is provided.

FIG. 1 is a schematic cross-sectional view showing the structure of a circuit board according to the present embodiment. FIG. 1 is a schematic cross-sectional view showing the configuration of an electronic device using a metal base substrate according to the present embodiment.

Embodiments of the present invention will be described below with reference to the drawings. Note that in all the drawings, similar components are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate. In addition, "~" means "from the above to the following" unless otherwise specified.

[Thermosetting resin composition]
The thermosetting resin composition of this embodiment includes an epoxy resin and a curing agent. The epoxy resin used in the thermosetting resin composition of this embodiment has a specific mesogenic skeleton. Thereby, the cured product of the thermosetting resin composition obtained has high thermal conductivity.
The components used in the thermosetting resin composition of this embodiment will be explained below.

(Epoxy resin)
The epoxy resin used in the thermosetting resin composition of this embodiment has a structure represented by formula (1).

In formula (1),
n represents the number of repetitions of the structure in parentheses, and is an integer of 1 or more. n is preferably 1 to 20, more preferably 1 to 15, and still more preferably 1 to 10.
Y is a group represented by formula (ep).

式（ｅｐ）中、ｒは、１～３の整数である。ｒは、好ましくは、１または２であり、より好ましくは、１である。
Ａは、メソゲン骨格を有する２価の基である。メソゲン骨格を有する２価の基としては、例えば、式（１－１）、式（１－２）、式（１－３）で表される基が挙げられる。

In formula (ep), r is an integer from 1 to 3. r is preferably 1 or 2, more preferably 1.
A is a divalent group having a mesogenic skeleton. Examples of the divalent group having a mesogenic skeleton include groups represented by formula (1-1), formula (1-2), and formula (1-3).

In formula (1-1), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and * represents a linking site. Examples of the alkyl group having 1 to 3 carbon atoms include methyl group, ethyl group, n-propyl group, and iso-propyl group.

In formula (1-2), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and * represents a linking site. Examples of the alkyl group having 1 to 3 carbon atoms include methyl group, ethyl group, n-propyl group, and iso-propyl group.

In formula (1-3), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and * represents a linking site. Examples of the alkyl group having 1 to 3 carbon atoms include methyl group, ethyl group, n-propyl group, and iso-propyl group.

B is -(CH ₂ ) _p - or -O-(CH ₂ ) _q -O-, where p and q are integers from 2 to 6. p and q are preferably integers from 2 to 4.

Specific examples of the epoxy resin used in the thermosetting resin composition of the present embodiment include compounds represented by the following formulas (EP1-1), (EP1-2), and (EP1-3). .

In formula (EP1-1),
n represents the number of repetitions of the structure in parentheses, and is an integer of 1 or more,
A plurality of R ^1s , R ^2s , R ^3s , R ^4s , R ^5s , R ^6s , R ^7s , and R ^8s are the same, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
X is an alkylene group having 2 to 6 carbon atoms,
Y is a group represented by the above formula (ep).

In formula (EP1-2),
Two R ^1s , R ^2s , R ^3s , and R ^4s are the same, and R ¹ , R ² , R ³ , and R ⁴ are independently a hydrogen atom or a carbon atom with 1 to 1 carbon atoms. 3 is an alkyl group,
R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
X is an alkylene group having 2 to 4 carbon atoms,
Y is a group represented by the above formula (ep).

In formula (EP1-3),
n represents the number of repetitions of the structure in parentheses, and is an integer of 1 or more,
A plurality of R ^1s , R ^2s , R ^3s , R ^4s , R ^5s , R ^6s , R ^7s , and R ^8s are the same, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
X is an alkylene group having 2 to 6 carbon atoms,
Y is a group represented by the above formula (ep).

(hardening agent)
Examples of the curing agent used in the thermosetting resin composition of this embodiment include phenol resins, amine compounds, active ester compounds, acid anhydrides, and cyanate compounds. These curing agents may be used alone or in combination of two or more.

Examples of the phenolic resin used as a curing agent include novolac type phenolic resins such as phenol novolak resin, cresol novolak resin, and bisphenol A novolac resin, and resol type phenolic resin. One type of these may be used alone, or two or more types may be used in combination.

Amine compounds used as curing agents include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylene diamine (MXDA), diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenyl. Aromatic polyamines such as sulfone (DDS); polyamine compounds such as dicyandiamide (DICY) and organic acid dihydrazide; tertiary amines such as triethylamine, tributylamine, and 1,4-diazabicyclo[2.2.2]octane. .

Examples of active ester compounds used as curing agents include aromatic ester compounds.
Acid anhydrides used as curing agents include alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA); trimellitic anhydride (TMA) and pyromellitic anhydride (PMDA). ), aromatic acid anhydrides such as benzophenonetetracarboxylic acid (BTDA), and the like.
Examples of the cyanate ester compound as a curing agent include a novolac type cyanate ester compound, a bisphenol A type cyanate ester compound, a dicyclopentadiene type cyanate ester compound, and the like. Examples of the isocyanate compound include various isocyanate prepolymers, blocked isocyanates, and the like.

The content of the curing agent in the thermosetting resin composition is not particularly limited, but for example, it is preferably 1% by mass or more and 12% by mass or less, and 3% by mass or more and 10% by mass, based on the entire resin composition. It is more preferable that it is below. By setting the content of the curing agent to the above lower limit or more, it becomes easier to appropriately cure the resin composition. On the other hand, by controlling the content of the curing agent to be equal to or less than the above upper limit, appropriate fluidity can be maintained.

(hardening accelerator)
The thermosetting resin composition of this embodiment can contain a curing accelerator, if necessary.
Although the type and amount of the curing accelerator are not particularly limited, an appropriate one can be selected from the viewpoints of reaction rate, reaction temperature, storage stability, etc.

Examples of the curing accelerator include imidazole compounds, phosphine compounds, and phenol compounds. These may be used alone or in combination of two or more. Among these, from the viewpoint of improving heat resistance, it is preferable to use a nitrogen atom-containing compound such as an imidazole compound.

Examples of imidazoles include imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl -4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl- 2-Undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2'-Methylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino -6-[2'-ethyl-4-methylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl(1')]-ethyl-s-triazine isocyanuric acid adduct of 2-phenylimidazole, isocyanuric acid adduct of 2-methylimidazole, 2-phenyl-4,5-dihydroxydimethylimidazole, 2-phenyl-4-methyl-5-hydroxymethyl Examples include imidazole.

Examples of the phosphine compound include triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium/tetraphenylborate, triphenylphosphine/triphenylborane, and 1,2-bis-(diphenylphosphino)ethane.

Examples of the phenol compound include phenol resin, bisphenol A, nonylphenol, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, and allylphenol.

The content of the curing accelerator may be 0.01% by mass to 10% by mass, 0.02% by mass to 5% by mass, or 0.05% by mass with respect to the total 100% by mass of the thermosetting resin. It may be up to 1.5% by mass.

(thermal conductive filler)
The thermosetting resin composition of this embodiment can contain a thermally conductive filler, if necessary.
The thermally conductive filler can include, for example, highly thermally conductive inorganic particles having a thermal conductivity of 20 W/m·K or more. The highly thermally conductive inorganic particles may include, for example, at least one selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and magnesium oxide. These may be used alone or in combination of two or more.

The boron nitride may include monodisperse particles, agglomerated particles, or a mixture thereof of scaly boron nitride. The flaky boron nitride may be granulated. By using aggregated particles of scale-like boron nitride, thermal conductivity can be further enhanced. The aggregated particles may be sintered particles or non-sintered particles.

The content of the thermally conductive filler is 100% by mass to 400% by mass, preferably 150% by mass to 350% by mass, and more Preferably it is 200% to 330% by weight. Thermal conductivity can be improved by making it equal to or more than the lower limit value. By setting it below the upper limit value, deterioration in processability can be suppressed.

(Silane coupling agent)
The thermosetting resin composition may include a silane coupling agent. Thereby, the compatibility of the thermally conductive filler in the thermosetting resin composition can be improved. The coupling agent may be added to the thermosetting resin composition, or may be used by treating the surface of the thermally conductive filler.

(Other additives)
The thermosetting resin composition of this embodiment can contain other components other than the components mentioned above. Examples of other components include antioxidants and leveling agents.

(solvent)
The thermosetting resin composition of this embodiment can contain a solvent, if necessary.
Examples of the solvent include acetone, methyl isobutyl ketone, toluene, ethyl acetate, cyclohexane, heptane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve series, carbitol series, anisole, and N-methyl. Examples include pyrrolidone.

[Method for producing thermosetting resin composition]
The thermosetting resin composition of the present embodiment can be produced by dissolving, mixing, and stirring the above-mentioned components other than the thermally conductive filler in the above-mentioned solvent to create a resin varnish (a varnish-like thermosetting resin composition). things) can be adjusted. For this mixing, various mixers such as an ultrasonic dispersion method, a high-pressure collision dispersion method, a high-speed rotation dispersion method, a bead mill method, a high-speed shear dispersion method, and a rotation-revolution dispersion method can be used.

A thermosetting resin composition in a B-stage state can be obtained by adding a thermally conductive filler to the resin varnish and kneading it using a triple roll or the like. By adding the inorganic filler during kneading, it is possible to more uniformly disperse the inorganic filler in the thermosetting resin, but the inorganic filler is not limited thereto. The thermally conductive filler may be added during kneading, or may be added during mixing of the resin varnish. In addition, from the viewpoint of dispersibility, it is preferable that the nanoparticles be dispersed in a predetermined solvent (nanoparticle dispersion) and added to the resin varnish. After kneading, the mixture may be cooled and solidified, and the kneaded product may be processed into granules, tablets, or sheets.

[Resin sheet]
The resin sheet of this embodiment is obtained by curing the thermosetting resin composition. A specific form of the resin sheet includes a carrier base material and a resin layer made of the thermosetting resin composition of this embodiment provided on the carrier base material.

The resin sheet can be obtained, for example, by subjecting a coating film (resin layer) obtained by coating a varnish-like thermosetting resin composition onto a carrier base material to a solvent removal treatment. The solvent content in the resin sheet can be 10% by mass or less based on the entire thermosetting resin composition. For example, the solvent removal treatment can be performed at 80° C. to 200° C. for 1 minute to 30 minutes.

Further, in this embodiment, as the carrier base material, for example, a polymer film, metal foil, etc. can be used. The polymer film is not particularly limited, but includes, for example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, release papers such as silicone sheets, and heat-resistant materials such as fluorine resins and polyimide resins. Examples include thermoplastic resin sheets having the following properties. The metal foil is not particularly limited, but includes, for example, copper and/or copper-based alloys, aluminum and/or aluminum-based alloys, iron and/or iron-based alloys, silver and/or silver-based alloys, gold and gold-based alloys. , zinc and zinc-based alloys, nickel and nickel-based alloys, tin and tin-based alloys, and the like.

A cured resin sheet is used as a thermally conductive sheet interposed between a heating element and a heat radiating element. Examples of the heating element include semiconductor elements, LED elements, substrates on which semiconductor elements and LED elements are mounted, central processing units (CPUs), power semiconductors, lithium ion batteries, fuel cells, and the like. Examples of the heat dissipation body include a heat sink, a heat spreader, a heat dissipation (cooling) fin, and the like.

[Resin board]
The resin substrate of this embodiment is composed of a cured product of the above thermosetting resin composition. This resin substrate can be used as a material for a printed circuit board on which electronic components such as LEDs and power modules are mounted.

[Circuit board]
A circuit board (heat dissipating resin member) 100 of this embodiment will be described based on FIG. 1.
FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a circuit board 100.

As shown in FIG. 1, the circuit board 100 can include a metal substrate 101, an insulating layer 102 provided on the metal substrate 101, and a metal layer 103 provided on the insulating layer 102. This insulating layer 102 can be composed of one selected from the group consisting of a resin layer made of the above-mentioned thermosetting resin composition, a cured product of the thermosetting resin composition, and a laminate. Each of these resin layers and laminates may be made of a thermosetting resin composition (resin sheet) in a B-stage state before circuit processing of the metal layer 103, and after circuit processing, it may be made of a thermosetting resin composition (resin sheet). It may be a cured product obtained by curing treatment.

The metal layer 103 is provided on the insulating layer 102 and is subjected to circuit processing. Examples of the metal constituting this metal layer 103 include one or more selected from copper, copper alloy, aluminum, aluminum alloy, nickel, iron, tin, and the like. Among these, the metal layer 103 is preferably a copper layer or an aluminum layer, and particularly preferably a copper layer. By using copper or aluminum, the circuit workability of the metal layer 103 can be improved. The metal layer 103 may be made of metal foil that is available in plate form or may be made of metal foil that is available in roll form.

The lower limit of the thickness of the metal layer 103 is, for example, 0.01 mm or more, preferably 0.035 mm or more, so that it can be applied to applications requiring high current.
Further, the upper limit of the thickness of the metal layer 103 is, for example, 10.0 mm or less, preferably 5 mm or less. When the value is below such a value, circuit workability can be improved and the overall thickness of the board can be reduced.

The metal substrate 101 has a role of dissipating heat accumulated in the circuit board 100. The metal substrate 101 is not particularly limited as long as it is a heat-dissipating metal substrate, and examples thereof include a copper substrate, a copper alloy substrate, an aluminum substrate, and an aluminum alloy substrate. A copper substrate or an aluminum substrate is preferable, and a copper substrate is more preferable. By using a copper substrate or an aluminum substrate, the metal substrate 101 can have good heat dissipation properties.
The thickness of the metal substrate 101 can be appropriately set as long as the purpose of the present invention is not impaired.

The upper limit of the thickness of the metal substrate 101 is, for example, 20.0 mm or less, preferably 5.0 mm or less. It is possible to improve the workability of the circuit board 100 having a value equal to or less than this value in external shape processing, cutting-out processing, etc.

Further, the lower limit of the thickness of the metal substrate 101 is, for example, 0.01 mm or more, preferably 0.6 mm or more. By using the metal substrate 101 having a value greater than or equal to this value, the heat dissipation performance of the circuit board 100 as a whole can be improved.

In this embodiment, the circuit board 100 can be used for various board applications, and because it has excellent thermal conductivity and heat resistance, it can be used as a printed circuit board that uses LEDs and power modules.

The circuit board 100 can have a metal layer 103 on which a circuit is processed by etching or the like into a pattern. In this circuit board 100, a solder resist (not shown) may be formed on the outermost layer, and connection electrode portions may be exposed so that electronic components can be mounted by exposure and development.

The circuit board 100 of the embodiment can be used in various applications requiring heat dissipation and insulation properties, and can be used, for example, in electronic devices such as semiconductor devices.
FIG. 2 is a schematic cross-sectional view showing an example of a semiconductor device using the circuit board 100.
A semiconductor element 201 is mounted on a metal layer 103 of a circuit board 100 via an adhesive layer 202 (die attach material). The semiconductor element 201 is connected to a connection electrode portion formed on the metal base substrate 100 via a bonding wire 203, and is mounted on the circuit board 100.
The semiconductor element 201 is then collectively sealed on the circuit board 100 with a sealing resin layer 205.

A heat sink 207 is provided on the metal substrate 101 side of the metal base substrate 100 via a thermally conductive layer 206 (thermal interface material (TIM)). The heat sink 207 is made of a material with excellent thermal conductivity, and examples thereof include metals such as aluminum, iron, and copper.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above may also be adopted.

EXAMPLES The present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Examples 1 to 16, Comparative Examples 1 to 2]
<Preparation of thermosetting resin composition>
A thermosetting resin composition was obtained according to the blending ratios shown in Table 1.
Details of each component in Table 1 are as follows. In addition, the unit of the amount of each component in Table 1 is parts by mass.

(Epoxy resin)
- Epoxy resin 1: Epoxy resin represented by formula (EP11).
The epoxy resin represented by formula (EP11) was synthesized by the following procedure.
16.8 parts by weight of 3,3'-dimethyl-4,4'-dihydroxybiphenyl (manufactured by Honshu Kagaku Co., Ltd.), 26.5 parts by weight of a 30% aqueous sodium hydroxide solution and 50.2 parts by weight of methanol were mixed, Warmed to ℃. 6.4 parts by weight of 1,4-dibromobutane was slowly added dropwise over 2 hours, and after the addition was completed, the mixture was stirred at 60°C for 4 hours. The precipitate was filtered, washed with 500 mL of pure water, adjusted to pH around 6 with hydrochloric acid, and further washed with 500 mL of pure water to obtain Intermediate A as a white solid in a yield of 78%.
19.6 parts by weight of Intermediate A, 0.2 parts by weight of tetrabutylammonium chloride, 37.5 parts by weight of epichlorohydrin and 36.5 parts by weight of dimethyl sulfoxide were added and stirred for 1 hour while heating at 40°C. . 3 parts by weight of a 50% aqueous sodium hydroxide solution was slowly added dropwise, and after the addition was completed, the mixture was heated to 50°C and stirred for 1 hour. 6 parts by weight of 50% sodium hydroxide was further slowly added dropwise, and the temperature was raised to 90°C. After heating and stirring at 90° C. for 6 hours, the mixture was cooled, tetrahydrofuran was added, and insoluble matter was filtered off. The filtrate was washed with pure water and decanted. The recovered brown viscous solid was dissolved in tetrahydrofuran, dried over magnesium sulfate, and the solvent was distilled off to obtain the target compound (EP11) as a light brown solid in a yield of 72%. The structure of compound (EP11) was confirmed from the following ¹ H-NMR data. The weight average molecular weight of the compound (EP11) in terms of polystyrene UV by GPC was 750.

^1H -NMR (400MHz, DMSO-d ₆ ): 7.34 (m, 8H, Ar-H), 6.97 (m, 4H, Ar-H), 4.31 (m, 2H, CH ₂ ) , 4.09 (m, 4H, O- CH ₂ -CH ₂ ), 3.94 (m, 2H, CH ₂ ), 3.33 (m, 2H, CH), 2.83 (m, 2H, CH ₂ ), 2.73 (m, 2H, CH ₂ ), 2.21 (d, J=9.2Hz, 12H, Ar- CH ₃ ), 1.95 (m, 4H, O-CH ₂ - CH ₂ )

- Epoxy resin 2: Epoxy resin represented by formula (EP12).
The epoxy resin represented by formula (EP12) was synthesized by the following procedure.
10.8 parts by weight of 4-hydroxybenzaldehyde (manufactured by Tokyo Kasei Co., Ltd.), 0.3 parts by weight of zinc chloride (manufactured by Tokyo Kasei Co., Ltd.), and 50 parts by weight of ethanol were mixed while heating to 40-50°C. While stirring, a solution of 8.9 parts by weight of 4,4'-ethylenedianiline dissolved in 40 parts by weight of ethanol was added dropwise, and after the addition was completed, the reaction was allowed to proceed under reflux conditions for 4 hours. After the reaction, the solution was cooled to room temperature and directly recrystallized to obtain Intermediate B as a yellow solid in a yield of 71%.
22.6 parts by weight of Intermediate B, 0.2 parts by weight of tetrabutylammonium chloride, 49.6 parts by weight of epichlorohydrin and 19.3 parts by weight of dimethyl sulfoxide were added and stirred for 1 hour while heating at 40°C. . 4 parts by weight of a 50% aqueous sodium hydroxide solution was slowly added dropwise, and after the addition was completed, the mixture was heated to 50° C. and stirred for 1 hour. 8 parts by weight of 50% sodium hydroxide was further slowly added dropwise, and the temperature was raised to 90°C. After heating and stirring at 90° C. for 6 hours, the mixture was cooled, tetrahydrofuran was added, and insoluble matter was filtered off. The filtrate was washed with pure water and decanted. The recovered brown viscous solid was dissolved in tetrahydrofuran, dried over magnesium sulfate, and the solvent was distilled off to obtain the target compound (EP12) as a pale yellow solid in a yield of 81%. The structure of compound (EP12) was confirmed from the following ¹ H-NMR data.

¹ H-NMR (400 MHz, DMSO-d ₆ ): 8.52 (s, 2H, CH), 7.86 (d, 2H, J=8.4Hz, Ar-H), 7.24 (d, 2H , J = 8.4Hz, Ar-H), 7.14 (d, 2H, J = 8.4Hz, Ar-H), 7.08 (d, 2H, J = 8.4Hz, Ar-H), 4.40 (dd, 2H, J=2.8, 11.2Hz, CH ₂ ), 3.94 (dd, 2H, J=6.4, 11.2Hz, CH ₂ ), 3.34 (d, 2H, J = 2.8Hz, CH), 2.91 (s, 4H, CH ₂ ), 2.85 (dd, 2H, J = 2.8, 6.4Hz, CH ₂ ), 2.72 (dd , 2H, J=2.8, 6.4Hz, CH ₂ )

- Epoxy resin 3: Epoxy resin represented by formula (EP13).
The epoxy resin represented by formula (EP13) was synthesized by the following procedure.
21.7 parts by weight of daidzein (manufactured by Tokyo Kasei Co., Ltd.), 26.5 parts by weight of a 30% aqueous sodium hydroxide solution, and 50.2 parts by weight of methanol were mixed and heated to 60°C. 6.4 parts by weight of 1,4-dibromobutane was slowly added dropwise over 2 hours, and after the addition was completed, the mixture was stirred at 60°C for 4 hours. The precipitate was filtered, washed with 500 mL of pure water, adjusted to pH around 6 with hydrochloric acid, and further washed with 500 mL of pure water to obtain Intermediate C as a white solid in a yield of 76%.
22.1 parts by weight of Intermediate C, 0.2 parts by weight of tetrabutylammonium chloride, 37.5 parts by weight of epichlorohydrin and 36.5 parts by weight of dimethyl sulfoxide were added and stirred for 1 hour while heating at 40°C. . 3 parts by weight of a 50% aqueous sodium hydroxide solution was slowly added dropwise, and after the addition was completed, the mixture was heated to 50°C and stirred for 1 hour. 6 parts by weight of 50% sodium hydroxide was further slowly added dropwise, and the temperature was raised to 90°C. After heating and stirring at 90° C. for 6 hours, the mixture was cooled, tetrahydrofuran was added, and insoluble matter was filtered off. The filtrate was washed with pure water and decanted. The recovered brown viscous solid was dissolved in tetrahydrofuran, dried over magnesium sulfate, and the solvent was distilled off to obtain the target compound (EP13) as a light brown solid in a yield of 83%. The structure of compound (EP13) was confirmed from the following ¹ H-NMR data. The weight average molecular weight of the compound (EP13) in terms of polystyrene UV by GPC was 1120.

^1H -NMR (400MHz, DMSO- _d6 ): 8.35 (s, 2H, CO- CH- O), 8.04 (d, J=8.8Hz, 2H, Ar-H), 7.52 (d, J=9.2Hz, 4H, Ar-H), 7.02 (m, 8H, Ar-H), 4.52 (m, 2H, CH ₂ ), 4.11 (m, 4H, O -CH ₂ -CH ₂ ), 4.05 (m, 2H, CH ₂ ), 3.37 (m, 2H, CH), 2.84 (m, 2H, CH ₂ ), 2.75 (m, 2H , CH2), 1.91 (m, 4H, O-CH ₂ -CH ₂ )

・Epoxy resin 4: Biphenyl type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX-4000HK)
・Epoxy resin 5: Bisphenol A epoxy (manufactured by DIC, jER828)

(hardening agent)
・Curing agent 1: Cyanate resin (manufactured by Lonza, Primaset "PT-30")
・Curing agent 2: Pyromellitic anhydride (PMDA) (manufactured by Tokyo Chemical Industry Co., Ltd.)
・Curing agent 3: 4,4'-diaminodiphenylmethane (DDM) (manufactured by Tokyo Kasei Kogyo Co., Ltd.)
・Curing agent 4: 4,4'-diaminodiphenylsulfone (DDS) (manufactured by Tokyo Kasei Kogyo Co., Ltd.)
・Curing agent 5: Phenol novolac resin (manufactured by Sumitomo Bakelite Co., Ltd.)

(hardening accelerator)
・Curing accelerator 1: 2-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.)

<Measurement of physical properties of resin molded article of thermosetting resin composition>
The following physical properties of the cured product (resin molded product) of the thermosetting resin composition were measured. The results are shown in Table 1.

(Thermal conductivity)
・Preparation of resin molding The epoxy resin, curing agent, and curing accelerator are melted and mixed on a hot plate at 150°C in the amounts shown in Table 1, cooled to room temperature, and pulverized to form a thermosetting resin. It became a thing. The prepared mixture was compression molded at 150° C./2 MPa for 15 minutes (condition 1) and then heat treated in an oven at 180° C. for 3 hours, or (condition 2) after compression molded at 180° C./2 MPa for 15 minutes. , heat treatment was performed in an oven at 180° C. for 3 hours to produce a cured product.
The obtained sample was subjected to a blackening treatment using a graphite film forming spray, and the thermal diffusivity at room temperature was measured using TD-1 manufactured by ULVAC.

Claims (11)

An epoxy resin represented by formula (1),
A thermosetting resin composition comprising a curing agent,

In formula (1),
n represents the number of repetitions of the structure in parentheses, and is an integer of 1 or more,
Y is a group represented by formula (ep),
A is a divalent group having a mesogenic skeleton,
B is -(CH ₂ ) _p - or -O-(CH ₂ ) _q -O-, where p and q are integers from 2 to 6,

In the formula (ep), r is an integer from 1 to 3,
Thermosetting resin composition. The divalent group having a mesogenic skeleton is a group selected from a group represented by formula (1-1), formula (1-2), or formula (1-3),

In formula (1-1), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, * represents a linking site,

In formula (1-2), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, * represents a linking site,

In formula (1-3), R ¹ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and * represents a linking site,
The thermosetting resin composition according to claim 1. The thermosetting resin composition according to claim 1, wherein n in the formula (1) is 1. The thermosetting resin composition according to claim 1, wherein the curing agent is at least one selected from a phenol resin, an amine compound, an active ester compound, an acid anhydride, and a cyanate compound. The thermosetting resin composition according to claim 1, further comprising a curing accelerator. The thermosetting resin composition according to claim 5, wherein the curing accelerator is at least one selected from an imidazole compound, a phosphine compound, and a phenol compound. The thermosetting resin composition according to claim 1, further comprising a thermally conductive filler. The thermosetting resin composition according to claim 1, further comprising a solvent. A resin sheet obtained by forming the thermosetting resin composition according to any one of claims 1 to 8 into a film shape. A resin substrate comprising a cured product of the thermosetting resin composition according to any one of claims 1 to 8. a metal layer;
a resin layer laminated on at least one surface of the metal layer,
A circuit board, wherein the resin layer is made of a cured product of the thermosetting resin composition according to any one of claims 1 to 8.

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