Composition for insulating-film formation, insulating film, electronic device, multilayer object, and method for producing multilayer object

Abstract

A composition for insulating-film formation which comprises: a polyfunctional acrylate having 2-6 acrylic groups in the molecule; a free-radical photopolymerization initiator; and a solvent having a boiling point at atmospheric pressure of 100-250°C and a surface tension of 20-34 mN / m.

Description

Insulating film-forming composition, insulating film, electronic device, laminate, and method for manufacturing laminate

[0001] The present invention relates to an insulating film-forming composition, an insulating film, an electronic device, a laminate, and a method for producing the laminate.

[0002] As compositions for forming insulating films (insulating film-forming compositions) on building materials such as interior and exterior walls and sashes of buildings, for example, Japanese Patent Application Laid-Open Nos. 2001-240809 and 2022-29540 disclose compositions for forming heat-insulating layers containing binder resins, hollow particles, inorganic particles, etc. However, because these contain hollow particles or inorganic particles of approximately 1 to 100 μm, it has been difficult to form films with a uniform surface of 1 μm or less. In particular, with the increasing integration of semiconductor devices, development of multilayer stacked structures using three-dimensional packaging is progressing, and the importance of insulating films applied between electrodes is increasing.

[0003] In contrast, aerogels with pores of approximately 100 nm generally have excellent thermal insulation and gas adsorption properties. Aerogels made of silica gel have long been studied as a representative aerogel (Non-Patent Document 1). However, they are brittle materials that crumble with even slight deformation and can withstand very little stress. Therefore, their application as insulating films in electronic devices with multilayer structures has not progressed.

[0004] JP 2001-240809 A JP 2022-029540 A

[0005] Samuel Stephens Kistler, "Coherent Expanded Aerogels and Jellies," Nature, May 16, 1931, Vol. 127, p. 741

[0006] An object of the present invention is to provide an insulating film-forming composition capable of forming an insulating film having excellent insulating and heat-insulating properties.

[0007] The invention made to solve the above problems is a composition for forming an insulating film, which contains a polyfunctional acrylate having from 2 to 6 acrylic groups in one molecule, a radical photopolymerization initiator, and a solvent having a boiling point of from 100°C to 250°C under atmospheric pressure and a surface tension of from 20 to 34 mN / m.

[0008] According to the insulating film-forming composition of the present invention, an insulating film having excellent insulating properties and heat insulation properties can be formed.

[0009] The insulating film-forming composition, insulating film, electronic device, laminate, and method for producing the laminate of the present invention will be described in detail below.

[0010] <Insulating Film-Forming Composition> The insulating film-forming composition contains a polyfunctional acrylate having two to six acrylic groups per molecule (hereinafter also referred to as "polyfunctional acrylate [A]"), a radical photopolymerization initiator (hereinafter also referred to as "radical photopolymerization initiator [B]"), and a solvent having a boiling point of 100°C to 250°C under atmospheric pressure and a surface tension of 20 mN / m to 34 mN / m (hereinafter also referred to as "solvent [C]"). The insulating film-forming composition may contain a thickener (hereinafter also referred to as "thickener [D]") as a preferred component. The insulating film-forming composition may contain a barrier-forming agent (hereinafter also referred to as "barrier-forming agent [E]") as a preferred component. The insulating film-forming composition may contain other components (hereinafter simply referred to as "other components") other than [A] the polyfunctional acrylate, [B] the radical photopolymerization initiator, [C] the solvent, [D] the thickener, and [E] the barrier-forming agent, as necessary, within the range that does not impair the effects of the present invention.

[0011] This insulating film-forming composition can form an insulating film with excellent insulating and heat-insulating properties. The reason for this is not entirely clear, but it is presumed to be, for example, as follows. The insulating film-forming composition contains the polyfunctional acrylate [A] and the solvent [C], which suppresses shrinkage during insulating film formation, making it possible to form an insulating film with a high pore volume. A high pore volume reduces the relative dielectric constant and thermal conductivity of the insulating film by the amount of air contained in the pores, and it is therefore thought that an insulating film with excellent insulating and heat-insulating properties can be formed.

[0012] The solid content concentration of the insulating film-forming composition is preferably 5% by mass or more and 35 parts by mass or less. When the solid content concentration is within the above range, an insulating film with a high pore volume can be obtained. The lower limit of the solid content concentration is preferably 5% by mass, more preferably 10% by mass, and even more preferably 15% by mass. The upper limit of the solid content concentration is preferably 35% by mass, more preferably 30% by mass, and even more preferably 25% by mass. The solid content concentration refers to the concentration of all components other than the solvent [C] contained in the insulating film-forming composition.

[0013] Each component contained in the insulating film-forming composition will be described below.

[0014]

[0041] [Polyfunctional Acrylate (A)] The polyfunctional acrylate (A) is a polyfunctional acrylate having 2 to 6 acrylic groups in one molecule. By including the polyfunctional acrylate (A) in the insulating film-forming composition, shrinkage during the formation of the insulating film is suppressed, and as a result, a crack-free insulating film can be formed.

[0015] In this specification, the term "polyfunctional" is used to mean having multiple acrylic groups; for example, a "bifunctional acrylate" refers to a compound having two acrylic groups. The polyfunctional acrylate [A] is not particularly limited as long as it has two to six acrylic groups in one molecule and is soluble in the solvent [C] described below. The insulating film-forming composition can contain one or more types of polyfunctional acrylate [A].

[0016] The polyfunctional acrylate (A) is preferably a compound that is not a polymer. The term "polymer" refers to a compound having three or more repeating units.

[0017] Examples of bifunctional acrylates include ethylene glycol diacrylate, 1,3-propanediol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tricyclo[5.2.1.0] ２，６ Examples of the diacrylate include decanedimethanol diacrylate, polyethylene glycol diacrylate (having 4 to 15 repeating ethylene glycol units), and polypropylene glycol diacrylate (having 4 to 15 repeating propylene glycol units).

[0018] Examples of tri- to hexa-functional acrylates include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexa(meth)acrylate; a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate; ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, tri(2-(meth)acryloyloxyethyl)phosphate, succinic acid-modified pentaerythritol triacrylate, succinic acid-modified dipentaerythritol pentaacrylate, tripentaerythritol heptaacrylate, and tripentaerythritol octaacrylate.

[0019] [A] Examples of the polyfunctional acrylate include neopentyl glycol diacrylate, tricyclo[5.2.1.0 ２，６] Decane dimethanol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate; a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate is particularly preferred because it has a high crosslinking group concentration, produces a highly elastic cured product, and is suppressed from shrinking.

[0020] The lower limit of the content of the polyfunctional acrylate (A) in the insulating film-forming composition is preferably 5% by mass, more preferably 9% by mass, and even more preferably 12% by mass. The upper limit of the content is preferably 30% by mass, more preferably 25% by mass, and even more preferably 20 parts by mass. By setting the content within the above range, an aerogel with low dielectric constant and low thermal conductivity can be produced.

[0021] [Radical Photopolymerization Initiator (B)] Examples of the radical photopolymerization initiator (B) include compounds that can generate active species that can initiate a radical polymerization reaction of the polyfunctional acrylate (A) upon exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, electron beams, X-rays, etc. The insulating film-forming composition can contain one or more radical polymerization initiators (B).

[0022] By exposing a coating film of the insulating film-forming composition to light, radicals are generated from the radical photopolymerization initiator (B), and the crosslinking reaction of the polyfunctional acrylate (A) progresses, thereby accelerating curing and forming an insulating film.

[0023] Specific examples of the radical photopolymerization initiator (B) include O-acyloxime compounds, α-aminoketone compounds, α-hydroxyketone compounds, and acylphosphine oxide compounds.

[0024] Examples of the O-acyloxime compound include 1-[9-ethyl-6-(2-methylbenzoyl)-9.H.-carbazol-3-yl]-ethan-1-one oxime-O-acetate, 1-[9-ethyl-6-benzoyl-9.H.-carbazol-3-yl]-octan-1-one oxime-O-acetate, 1-[9-ethyl-6-(2-methylbenzoyl)-9.H.-carbazol-3-yl]-ethan-1-one oxime-O-benzoate, 1-[9-n-butyl-6-(2-ethylbenzoyl)-9.H.-carbazol-3-yl]-ethan-1-one oxime-O-benzoate, ethanone, 1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranylbenzoyl)-9.H. -carbazol-3-yl]-, 1-(O-acetyloxime), ethanone, 1-[9-ethyl-6-(2-methyl-4-tetrahydropyranylbenzoyl)-9.H. -carbazol-3-yl]-, 1-(O-acetyloxime), ethanone, 1-[9-ethyl-6-(2-methyl-5-tetrahydrofuranylbenzoyl)-9.H. -carbazol-3-yl]-, 1-(O-acetyloxime), ethanone, 1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxolanyl)methoxybenzoyl}-9.H. -carbazol-3-yl]-, 1-(O-acetyloxime), ethanone, 1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranylmethoxybenzoyl)-9.H. -carbazol-3-yl]-, 1-(O-acetyloxime), 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)].

[0025] Examples of the α-aminoketone compound include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, and 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one.

[0026] Examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexylphenyl ketone.

[0027] Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0028] As the radical photopolymerization initiator (B), from the viewpoint of further accelerating the curing reaction by radiation, an O-acyloxime compound or an acylphosphine oxide compound is preferable, and 1-[9-ethyl-6-(2-methylbenzoyl)-9,H-carbazol-3-yl]-ethan-1-one oxime-O-acetate, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, or bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide is more preferable.

[0029] The lower limit of the content of the radical photopolymerization initiator [B] in the insulating film-forming composition is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and even more preferably 1 part by mass, relative to 100 parts by mass of the polyfunctional acrylate [A]. The upper limit of the content is preferably 20 parts by mass, more preferably 10 parts by mass, and even more preferably 5 parts by mass, relative to 100 parts by mass of the polyfunctional acrylate [A]. By setting the content within the above range, the curing reaction due to radiation can be further promoted.

[0030] [Solvent (C)] The solvent (C) has a boiling point of 100°C or higher and 250°C or lower under atmospheric pressure (1 atm) and a surface tension of 20 mN / m or higher and 34 mN / m or lower. If the boiling point is lower than the lower limit, surface roughness occurs during curing. If the boiling point is higher than the upper limit, the cured product softens during heating and drying, resulting in significant shrinkage. Furthermore, if the surface tension is lower than the lower limit, the solubility of the monomer, etc. cannot be ensured. If the surface tension is higher than the upper limit, capillary force increases during solvent evaporation during the drying process, resulting in high stress and significant shrinkage. In the insulating film-forming composition, by using a solvent (C) whose boiling point and surface tension are both within the above-mentioned specific ranges, shrinkage during drying can be suppressed and surface roughness of the cured product can be prevented. The insulating film-forming composition can contain one or more solvents (C).

[0031] The lower limit of the boiling point of the solvent [C] is 100° C., preferably 120° C., and more preferably 150° C. The upper limit of the boiling point is 250° C., and preferably 230° C. When the boiling point of the solvent [C] is within the above preferred range, there is no need to perform drying at high temperature and high pressure to remove the solvent [C] when forming the insulating film, and therefore an insulating film having excellent mechanical strength while maintaining the pore structure can be produced.

[0032] The lower limit of the surface tension of the solvent [C] is 20 mN / m, preferably 23 mN / m. The upper limit of the surface tension is 34 mN / m, preferably 32 mN / m. When the surface tension of the solvent [C] is within the above-mentioned preferred range, an insulating film with a high pore volume can be obtained with low shrinkage and no cracking.

[0033] Examples of the solvent [C] include toluene, xylene, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methoxybutanol, mesitylene, cyclohexyl acetate, isobornyl acetate, methyl decanoate, decyl acetate, and decahydronaphthalene.

[0034] Among these, at least one selected from the group consisting of dipropylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, ethyl-3-ethoxypropionate, mesitylene, cyclohexyl acetate, isobornyl acetate, methyl decanoate, decyl acetate, and decahydronaphthalene is preferred. In this case, the boiling point and surface tension are particularly well balanced, and an insulating film with low shrinkage, no cracking, and a high pore volume can be obtained.

[0035] [D] Thickener The thickener [D] is a component that can impart flexibility to the insulating film to be formed and can suppress the occurrence of cracks. Examples of the thickener [D] include polysaccharides such as ethyl cellulose and hydroxypropyl cellulose, and synthetic polymers such as acrylic acid polymers, carboxyvinyl polymers, and polyethylene oxide.

[0036] When the insulating film-forming composition contains a thickener, the content of the thickener [D] is preferably 50 parts by mass or less, and more preferably 5 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the polyfunctional acrylate [A]. When the content of the thickener [D] is within the above range, the occurrence of cracks in the insulating film can be further suppressed.

[0037] [Barrier-forming agent (E)] The barrier-forming agent (E) has a molecular weight significantly different from that of the polyfunctional acrylate (A). Therefore, after forming a coating film from the composition, irradiating the coating film with ultraviolet light causes phase separation between the barrier-forming agent (E) and the polyfunctional acrylate (A), enabling the formation of a barrier film on the surface of the insulating film. This barrier film can be further heated, dried, or otherwise converted into a dense polymer film. Various films can be formed by further applying a film-forming composition or the like onto this barrier film.

[0038] [E] Examples of the barrier-forming agent include polystyrene, styrene copolymers, polycyclic olefins, cyclic olefin copolymers, cyclic olefin copolymers, cycloolefin polymers, polycarbonate, polymethyl methacrylate, acrylic resins, poly(ethylene / propylene)-polystyrene block copolymers (SEP), polystyrene-poly(ethylene / butylene) block copolymers (SEB), polystyrene-poly(ethylene / propylene)-polystyrene block copolymers (SEPS), polystyrene-poly(ethylene / butylene)-polystyrene block copolymers (SEBS), polystyrene-poly(ethylene-ethylene / propylene)-polystyrene block copolymers (SEEPS), polyolefin polymers, polystyrene-poly(ethylene / propylene) block copolymers, polystyrene-poly(ethylene / butylene) block copolymers, polystyrene-poly(ethylene / propylene)-polystyrene block copolymers, polystyrene-poly(ethylene / butylene)-polystyrene block copolymers, polystyrene-poly(ethylene-ethylene / propylene)-polystyrene block copolymers, and polystyrene-poly(ethylene-ethylene / propylene)-polystyrene block copolymers. The barrier-forming agent (E) can be used alone or in combination of two or more.

[0039] [E] The barrier-forming agent is preferably a poly(ethylene / propylene)-polystyrene block copolymer (SEP), a polystyrene-poly(ethylene / butylene) block copolymer (SEB), a polystyrene-poly(ethylene / propylene)-polystyrene block copolymer (SEPS), or a polystyrene-poly(ethylene / butylene)-polystyrene block copolymer (SEBS).

[0040] When the insulating film-forming composition contains the barrier-forming agent [E], the content of the barrier-forming agent [E] is preferably 50 parts by mass or less, and more preferably 3 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the polyfunctional acrylate [A].

[0041] [Other Components] Examples of other components include an adhesion aid, a surfactant, and a polymerization inhibitor.

[0042] An adhesion aid can be used to further improve the adhesion between the insulating film to be formed and the substrate. Examples of the adhesion aid include trimethoxysilylbenzoic acid, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylalkyldialkoxysilane, γ-chloropropyltrialkoxysilane, γ-mercaptopropyltrialkoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0043] When the insulating film-forming composition contains an adhesion aid, the content of the adhesion aid is preferably 20 parts by mass or less, and more preferably 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the polyfunctional acrylate [A]. When the content of the adhesion aid is within the above range, the adhesion between the substrate and the insulating film to be formed is improved.

[0044] Examples of surfactants include fluorine-based surfactants and silicon-based surfactants. When the insulating film-forming composition contains a surfactant, the content of the surfactant is preferably 1 part by mass or less, and more preferably 0.01 parts by mass or more and 0.6 parts by mass or less, per 100 parts by mass of the polyfunctional acrylate (A).

[0045] The polymerization inhibitor is a component that suppresses the cleavage of the polyfunctional acrylate molecules (A) by capturing radicals generated by exposure or heating or by decomposing peroxides generated by oxidation. When the insulating film-forming composition contains a polymerization inhibitor, degradation due to cleavage of polymer molecules in the insulating film to be formed is suppressed, thereby improving the light resistance of the insulating film.

[0046] Examples of the polymerization inhibitor include hindered phenol compounds, hindered amine compounds, alkyl phosphite compounds, and thioether compounds, with hindered phenol compounds being preferred.

[0047] When the insulating film-forming composition contains a polymerization inhibitor, the content of the polymerization inhibitor is preferably 1 part by mass or less, and more preferably 0.01 parts by mass or more and 0.6 parts by mass or less, per 100 parts by mass of the polyfunctional acrylate (A).

[0048] <Method for forming insulating film> Examples of a method for forming an insulating film using the insulating film-forming composition include a method including a step of irradiating (exposing) the insulating film-forming composition with radiation to obtain a gel (hereinafter also referred to as a "gel-forming step"), and a step of drying the gel (hereinafter also referred to as a "drying step").

[0049] Each step will be described below.

[0050] [Gel Formation Step] In this step, the insulating film-forming composition is irradiated (exposed) with radiation to form a gel through a photocuring reaction. The reaction conditions for the photocuring reaction are not particularly limited as long as a gel can be obtained, and the reaction temperature, reaction time, etc. can be within the same ranges as those for conventional gels. The photocuring reaction is preferably carried out in an inert gas atmosphere such as nitrogen or argon. Typically, the radiation used can be, for example, visible light, ultraviolet light, far ultraviolet light, electron beams, or X-rays. Among these types of radiation, radiation with a wavelength in the range of 190 nm to 450 nm is preferred, and radiation containing 365 nm ultraviolet light is more preferred.

[0051] The lower limit of the exposure dose in this step is 10 mJ / cm as a value measured by an illuminance meter (OAI model 356, manufactured by OAI Optical Associates Inc.) at a wavelength of 365 nm. ２ is preferred, and 20 mJ / cm ２ The upper limit of the exposure dose is more preferably 2,000 mJ / cm as measured by the illuminometer. ２ is preferred, and 1,000 mJ / cm２ It is also possible to form a pattern by exposure through a photomask, or by an imprint method using a mold.

[0052] [Drying Step] In this step, the formed gel is dried to obtain an insulating film. Known methods can be used to dry the gel. Examples include atmospheric drying, freeze-drying, and supercritical drying, with atmospheric drying being preferred. By precisely controlling the atmospheric drying conditions, destruction and shrinkage of the gel skeleton can be suppressed, which is preferable. Furthermore, when drying the gel by supercritical drying, the dispersion medium is removed at a temperature and pressure equal to or higher than the critical point of the dispersion medium of the gel. In the case of supercritical drying, it is preferable to perform the solvent substitution described above, whereby the dispersion medium of the gel is replaced from the reaction solvent with ethanol, and then further replaced with liquefied carbon dioxide.

[0053] <Insulating Film> The insulating film is formed from the insulating film-forming composition described above. The insulating film functions as, for example, a protective film, an interlayer insulating film, a planarizing film, a gate insulating film, etc. The insulating film has a high pore volume, and therefore has a low dielectric constant and a low thermal conductivity. Furthermore, the insulating film has a low refractive index.

[0054] The insulating film is a porous film having a plurality of pores, the diameter of which is preferably 1 nm or more and 500 nm or less, and is made of aerogel.

[0055] The insulating film is formed from the insulating film-forming composition described above, and therefore contains a polymer having repeating units derived from the polyfunctional acrylate (A) described above.

[0056] The insulating film may be a free-standing film or a film that constitutes a part of a laminate. In this specification, the term "free-standing film" means a film that can maintain its shape even without the presence of another substrate or support.

[0057] The pore volume of the insulating film is 0.3 cm ３ / g or more 1.5cm ３ / g or less. When the pore volume of the insulating film is in the above range, it can exhibit a low dielectric constant and low thermal conductivity. The pore volume of the insulating film can be measured by the measurement method described in the Examples below.

[0058] The lower limit of the pore volume is 0.3 cm ３ / g is preferred, and 0.4 cm ３ / g is more preferred, and 0.5 cm ３ / g may be more preferable. The upper limit of the pore volume is 1.5 cm ３ / g is preferred, and 1.0 cm ３ / g is more preferable, and 0.9 cm ３ / g is more preferable, and 0.8 cm ３ / g may be preferred in some cases.

[0059] The dielectric constant of the insulating film is preferably 1.2 or more and 2.0 or less. When the dielectric constant of the insulating film is within the above range, it can be used as an insulating film that suppresses propagation delay. The lower limit of the dielectric constant is preferably 1.2, more preferably 1.3, and in some cases 1.4. The upper limit of the dielectric constant is preferably 2.0, more preferably 1.9, and in some cases 1.8. The dielectric constant of the insulating film can be measured by the measurement method described in the Examples below.

[0060] The density of the insulating film is 0.05 g / cm ３ 0.30g / cm or more ３ It is preferable that the density of the insulating film is in the above range, so that an insulating film having more excellent insulating properties and heat insulating properties can be obtained. Although a restrictive interpretation is not intended, the lower the density within the above range, the more excellent the insulating properties and heat insulating properties tend to be. The lower limit of the density is 0.05 g / cm ３ is preferred, and 0.10 g / cm ３ More preferably, 0.20 g / cm ３ is more preferably 0.21 g / cm ３ The upper limit of the density is preferably 0.30 g / cm ３ is preferred, and 0.29 g / cm ３ More preferably, 0.27 g / cm３ The density of the insulating film can be measured by the measurement method described in the Examples below.

[0061] The thermal conductivity of the insulating film is preferably 0.020 W / mK or more and 0.050 W / mK or less. When the thermal conductivity of the insulating film is in the above range, it can be preferably used as an insulating film for thermal management. The lower limit of the thermal conductivity is preferably 0.020 W / mK, more preferably 0.025 W / mK. The upper limit of the thermal conductivity is preferably 0.050 W / mK, more preferably 0.045 W / mK. The thermal conductivity of the insulating film can be measured by the measurement method described in the Examples below.

[0062] <Electronic Device> The electronic device includes the insulating film described above. Examples of the electronic device include a display element, a semiconductor device, a CMOS image sensor, and various other sensors.

[0063] <Laminate> The laminate is a laminate including a substrate and an insulating film laminated directly or indirectly on the substrate. The insulating film is formed from the insulating film-forming composition described above.

[0064] The laminate can be used as an electronic device such as a display element, a semiconductor device, a CMOS image sensor, or various other sensors. The insulating film provided in the laminate has a high pore volume, which allows air to be easily trapped in the pores, resulting in high insulation and heat insulation. Furthermore, the insulating film has a highly cross-linked structure, resulting in high mechanical strength. Therefore, the laminate can be suitably used in semiconductor devices with a multilayer structure.

[0065] [Substrate] The material of the substrate is not particularly limited, and examples thereof include glass, quartz, silicon, and resin. Specific examples of the resin include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, polyimide, addition polymers of cyclic olefins, ring-opening polymers of cyclic olefins, and hydrogenated products thereof.

[0066] <Method for manufacturing laminate> The method for manufacturing the laminate includes a step of applying an insulating film-forming composition directly or indirectly onto a substrate to form a coating film (hereinafter also referred to as a "coating film-forming step"), a step of exposing the coating film to light and drying it (hereinafter also referred to as a "drying step"), and a step of applying a film-forming composition onto the film obtained by the drying step and heating or exposing it to light to form a film (hereinafter also referred to as a "film-forming step"). In the coating film-forming step, the insulating film-forming composition used is one of the above-mentioned insulating film-forming compositions that contains the barrier forming agent (E).

[0067] According to the method for manufacturing the laminate, a laminate can be obtained that includes a substrate, an insulating film that is directly or indirectly laminated on the substrate, a barrier film that is formed on the insulating film, and a film that is formed on the barrier film.

[0068] According to this method for producing a laminate, a barrier film is formed on the aerogel insulating film by phase separation, making it possible to laminate a film that is difficult to laminate directly on the aerogel insulating film.

[0069] [Coating Film Forming Step] In this step, the insulating film forming composition is applied directly or indirectly onto a substrate to form a coating film.

[0070] Examples of the substrate include those described above in the section <Laminate>.

[0071] In this step, the insulating film forming composition used is one containing the barrier forming agent (E) from among the above-mentioned insulating film forming compositions.

[0072] The coating method is not particularly limited, and any known method can be used.

[0073] [Drying Step] In this step, the coating film obtained in the coating film forming step is exposed to light and dried. This step allows an insulating film to be formed on the substrate, and a barrier film to be formed on the insulating film. The methods and conditions for exposure and drying can be the same as those described for the gel forming step and drying step in the above section <Method for forming an insulating film>.

[0074] [Film Forming Step] In this step, a film is formed by applying a film-forming composition onto the barrier film obtained in the drying step, and then heating or exposing the composition to light.

[0075] The film-forming composition is not particularly limited as long as it is a composition capable of forming a film, and may be, for example, a mixture of an acrylate monomer and an initiator dissolved in an organic solvent.

[0076] The method for applying the film-forming composition is not particularly limited, and any known method can be used.

[0077] The heating conditions include, for example, 120° C. for 1 hour.

[0078] The exposure method and conditions may be the same as those described for the gel forming step and drying step in the above section <Method for forming insulating film>.

[0079] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0080] <Preparation of insulating film forming composition> The components used in preparing the insulating film forming composition are shown below.

[0081] [[A] Polyfunctional acrylate] (A-1): Pentaerythritol tetraacrylate (number of acrylic groups: 4) (A-2): Glycerol diacrylate (number of acrylic groups: 2) (A-3): Dipentaerythritol hexaacrylate (number of acrylic groups: 6) (A-4): "DPHA-40H" (number of acrylic groups: 10) manufactured by Nippon Kayaku Co., Ltd. (A-5): Tricyclo[5.2.1.0 ２，６ ] Decane dimethanol diacrylate (number of acrylic groups: 2)

[0082] [[B] Radical Photopolymerization Initiator] (B-1): Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide

[0083] [C] Solvents: (C-1): Dipropylene glycol monomethyl ether acetate (boiling point: 209°C, surface tension: 28.6 mN / m) (C-2): Mesitylene (boiling point: 165°C, surface tension: 27.6 mN / m) (C-3): Cyclohexyl acetate (boiling point: 172°C, surface tension: 31.3 mN / m) (C-4): Toluene (boiling point: 110°C, surface tension: 28.5 mN / m) (C-5): Anisole (boiling point: 154°C, surface tension: 34.6 mN / m) (C-6): Isopropyl alcohol (boiling point: 82°C, surface tension: 20.8 mN / m) (C-7): N,N-dimethylformamide (boiling point: 153°C, surface tension: 36.4 mN / m) (C-8): N-methyl-2-pyrrolidone (boiling point: 202°C, surface tension: 40.3 mN / m) (C-9): diethylene glycol dibutyl ether (boiling point: 255°C, surface tension: 28.7 mN / m) (C-10): isobornyl acetate (boiling point: 215°C, surface tension: 30.2 mN / m)

[0084] [[D] Thickener] (D-1): Ethyl cellulose (Sigma-Aldrich)

[0085] [[E] Barrier-forming agent] (E-1): "SEPTON 1020" from Kuraray Co., Ltd.

[0086] [Example 1] Preparation of insulating film-forming composition (J-1) 100 parts by mass of (A-1) as [A] polyfunctional acrylate and 3 parts by mass of (B-1) as [B] radical photopolymerization initiator were dissolved in 456 parts by mass of (C-1) as [C] solvent to prepare an insulating film-forming composition (J-1). The solids concentration of the insulating film-forming composition (J-1) was 18% by mass.

[0087] [Examples 2 to 9 and Comparative Examples 1 to 6] Preparation of insulating film-forming compositions (J-2) to (J-9) and (CJ-1) to (CJ-6) Insulating film-forming compositions (J-2) to (J-9) and (CJ-1) to (CJ-6) were prepared in the same manner as in Example 1, except that the types and amounts of each component shown in Table 1 below were used.

[0088] <Evaluation> An insulating film or laminate was formed using the insulating film-forming composition prepared above according to the following method. The resulting insulating film was evaluated for density, BET specific surface area, pore volume, thermal conductivity, dielectric constant, and cured surface appearance according to the following method. The resulting laminate was evaluated for BET specific surface area, pore volume, thermal conductivity, dielectric constant, and cured surface appearance according to the following method. Furthermore, for those that developed cracks during drying, it was not possible to measure density, BET specific surface area, pore volume, thermal conductivity, and dielectric constant. The results are shown in Table 1 below. In the section [Laminate Formation 2], the formed insulating film was evaluated for BET specific surface area, pore volume, thermal conductivity, dielectric constant, and cured surface appearance.

[0089] [Formation of insulating film] The insulating film-forming compositions (J-1) to (J-6), (J-8), and (CJ-1) to (CJ-6) prepared above were placed in polypropylene containers and irradiated with a 250 W high-pressure mercury lamp at room temperature for 30 minutes to obtain a precursor gel. This gel was removed from the polypropylene container and dried at 120°C under normal pressure to obtain an insulating film as a free-standing film.

[0090] [Laminate Formation 1] The insulating film-forming composition (J-7) prepared above was applied onto a quartz substrate, and the resulting coating film was irradiated with a 250 W high-pressure mercury lamp at room temperature for 30 minutes and dried at 120°C under normal pressure, thereby forming a laminate having an insulating film on the substrate.

[0091] [Laminate formation 2] The insulating film-forming composition (J-9) prepared above was applied to a quartz substrate, and the resulting coating was irradiated with a 250 W high-pressure mercury lamp at room temperature for 30 minutes, followed by drying at 150°C under normal pressure to form a film on the substrate. This film is a film in which an insulating film and a barrier film are laminated in this order. Furthermore, a film-forming oil composition (a mixture of a bifunctional acrylate monomer and a photoinitiator) was applied to the barrier film, and the film was irradiated with a 250 W high-pressure mercury lamp at room temperature for 30 minutes, thereby forming a film on the barrier film.

[0092] [Density] Density was measured by measuring the size and mass. For the size measurement, an arbitrary cross section of the insulating film was observed using a scanning electron microscope (SEM) under the following conditions. Measurement sample: The insulating film was sliced ​​into thin slices using a razor. Measurement device: Apreo S LoVac (manufactured by Thermo Fisher Scientific). Measurement conditions: 80 Pa, room temperature.

[0093] [BET specific surface area and pore volume] The BET specific surface area was measured by isothermal adsorption of nitrogen gas using a BELSORP18PLUS-HT (manufactured by BEL Japan) according to a standard method. The pore volume (pore diameter: approximately 0.5 to 50 nm) was calculated by the GCMC method.

[0094] [Thermal Conductivity] The thermal conductivity was measured using an ai-Phase Mobile-10 (manufactured by ai-Phase Corporation) by a temperature wave amplitude method / alternating current steady state method.

[0095] [Relative Dielectric Constant] The relative dielectric constant of the insulating film was measured by measuring the dielectric characteristics at 10 GHz using a cavity resonator method.

[0096] [Appearance of the cured product surface] After the insulating film-forming composition was photocured and dried, the light-irradiated surface was visually observed. If no roughness or the like was observed, the surface was rated as "A" (good), if slight irregularities were observed on the light-irradiated surface, the surface was rated as "B" (fairly good), and if cracks occurred in the insulating film, the surface was rated as "C" (poor).

[0097] In Table 1 below, the values ​​in the "Content" column indicate parts by mass. A "-" in the "Thickener (D)" and "Barrier-forming agent (E)" columns indicates that the corresponding component was not used. A "-" in the "Density" column indicates that the density was not measured.

[0098]

[0099] From the results in Table 1, it was found that Examples 1 to 9 had lower relative dielectric constants and thermal conductivities than Comparative Examples 1 and 2.

Claims

1. A composition for forming an insulating film, comprising: a multifunctional acrylate having 2 to 6 acrylic groups in one molecule; a radical photopolymerization initiator; and a solvent having a boiling point of 100°C to 250°C under atmospheric pressure and a surface tension of 20 mN / m to 34 mN / m.

2. The insulating film forming composition according to claim 1, wherein the content of the polyfunctional acrylate is 5% by mass or more and 30% by mass or less.

3. The insulating film forming composition according to claim 1, wherein the radical photopolymerization initiator is at least one selected from the group consisting of O-acyloxime compounds, α-aminoketone compounds, α-hydroxyketone compounds and acylphosphine oxide compounds.

4. The insulating film forming composition according to claim 1, wherein the solvent is at least one selected from the group consisting of dipropylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, ethyl-3-ethoxypropionate, mesitylene, cyclohexyl acetate, isobornyl acetate, methyl decanoate, decyl acetate and decahydronaphthalene.

5. The insulating film forming composition according to claim 1, further comprising a barrier forming agent.

6. An insulating film formed from the insulating film forming composition according to any one of claims 1 to 5.

7. The pore volume is 0.3 cm ３ / g or more 1.5cm ３ The insulating film according to claim 6, wherein the dielectric constant is 0.1 to 0.

5.

8. The insulating film according to claim 6, which has a relative dielectric constant of 1.2 or more and 2.0 or less.

9. The insulating film according to claim 6, which has a thermal conductivity of 0.020 W / mK or more and 0.050 W / mK or less.

10. Density is 0.05 g / cm ３ 0.30g / cm or more ３ The insulating film according to claim 6, wherein:

11. An electronic device comprising the insulating film according to claim 6.

12. A laminate comprising a substrate and an insulating film formed directly or indirectly on the substrate, the insulating film being formed from the insulating film forming composition according to any one of claims 1 to 5.

13. A method for manufacturing a laminate, comprising the steps of: applying the insulating film-forming composition according to claim 5 directly or indirectly onto a substrate to form a coating film; exposing the coating film to light and drying it; and applying a film-forming composition onto the insulating film obtained by the drying step, and heating or exposing the composition to light to form a film.