TWI868114B - Adhesive film for circuit connection and its manufacturing method, manufacturing method of circuit connection structure and adhesive film storage group - Google Patents

Abstract

A circuit connection adhesive film 1 includes: a first adhesive layer 2 and a second adhesive layer 3 laminated on the first adhesive layer 2, wherein the first adhesive layer 2 includes a photocurable material of a photo- and thermosetting composition, wherein the photo- and thermosetting composition includes a polymerizable compound, a photopolymerization initiator, a thermopolymerization initiator and conductive particles 4, and the second adhesive layer 3 includes a thermosetting composition.

Description

Adhesive film for circuit connection and its manufacturing method, manufacturing method of circuit connection structure and adhesive film storage group

The present invention relates to an adhesive film for circuit connection and a manufacturing method thereof, a manufacturing method for a circuit connection structure, and an adhesive film storage set.

Various adhesive materials have been used for circuit connection. For example, as an adhesive material used for connection between a liquid crystal display and a tape carrier package (TCP), connection between a flexible printed circuit (FPC) and a TCP, or connection between an FPC and a printed wiring board, an adhesive film for circuit connection having anisotropic conductivity and in which conductive particles are dispersed has been used.

In the field of precision electronic devices that use anisotropically conductive adhesive films for circuit connection, the density of circuits is increasing, and the electrode width and electrode spacing are becoming extremely narrow. Therefore, it is not always easy to efficiently capture conductive particles on tiny electrodes to obtain high connection reliability.

In this regard, for example, Patent Document 1 proposes a method of isolating conductive particles from each other by making them exist on one side of an anisotropic conductive adhesive sheet. [Prior Art Document] [Patent Document]

Patent Document 1: International Publication No. 2005/54388

[Problems to be solved by the invention] However, in the method of patent document 1, the conductive particles flow when the circuit is connected, so the conductive particles aggregate between the electrodes, which may cause a short circuit. In addition, the sparse and dense distribution of the conductive particles caused by the flow of the conductive particles not only reduces the insulation properties, but also may cause deviations in the connection resistance value, so there is still room for improvement.

Therefore, the purpose of the present invention is to provide an adhesive film for circuit connection that can suppress the flow of conductive particles that occurs during the manufacture of a circuit connection structure, a method for manufacturing the same, a method for manufacturing a circuit connection structure using the adhesive film, and an adhesive film storage set including the adhesive film. [Means for Solving the Problem]

One aspect of the present invention is a circuit connection adhesive film comprising: a first adhesive layer and a second adhesive layer laminated on the first adhesive layer, wherein the first adhesive layer comprises a photocurable material of a photo- and thermosetting composition, wherein the photo- and thermosetting composition comprises a polymerizable compound, a photopolymerization initiator, a thermopolymerization initiator and conductive particles, and the second adhesive layer comprises a thermosetting composition.

According to the circuit connection adhesive film of the aspect, the flow of conductive particles occurring during the manufacture of the circuit connection structure can be suppressed. According to such a circuit connection adhesive film, the connection resistance between the electrodes facing each other of the circuit connection structure can be reduced, and further, the low connection resistance can be maintained even in a high temperature and high humidity environment (e.g., 85°C, 85%RH). That is, according to the circuit connection adhesive film, the connection reliability of the circuit connection structure can be improved.

However, the circuit connection adhesive film is required not to peel off from the circuit component even when the circuit connection structure is used for a long time in a high temperature and high humidity environment (e.g., 85°C, 85%RH) after the circuit component is connected. The circuit connection adhesive film can also suppress the tendency of peeling at the interface between the circuit component and the circuit connection portion formed by the adhesive film when the circuit connection structure is used in a high temperature and high humidity environment.

The method for manufacturing a circuit connection adhesive film of one aspect of the present invention includes: a preparation step of preparing a first adhesive layer; and a lamination step of laminating a second adhesive layer containing a thermosetting composition on the first adhesive layer, wherein the preparation step includes a step of obtaining the first adhesive layer by irradiating a layer containing a photo- and thermosetting composition with light to cure the photo- and thermosetting composition, wherein the photo- and thermosetting composition contains a polymerizable compound, a photopolymerization initiator, a thermopolymerization initiator, and conductive particles. According to this method, a circuit connection adhesive film that can suppress the flow of conductive particles that occurs when manufacturing a circuit connection structure can be obtained.

The polymerizable compound may be a radical polymerizable compound having a radical polymerizable group, and may contain a radical polymerizable compound having a phosphate structure represented by the following formula (1). [In formula (1), n represents an integer of 1 to 3, and R represents a hydrogen atom or a methyl group]

The thermosetting composition may contain a radical polymerizable compound having a radical polymerizable group.

The photopolymerization initiator may have a structure represented by the following formula (I).

The structure represented by the formula (I) may be an oxime ester structure, a bisimidazole structure or an acridine structure.

The photopolymerization initiator may contain a compound having a structure represented by the following formula (VI). [In formula (VI), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an organic group containing an aromatic hydrocarbon group]

The thickness of the first adhesive layer may be 0.1 to 0.8 times the average particle size of the conductive particles.

The manufacturing method of the circuit connection structure according to one aspect of the present invention comprises: placing the above-mentioned circuit connection adhesive film between a first circuit component having a first electrode and a second circuit component having a second electrode, and hot pressing the first circuit component and the second circuit component to electrically connect the first electrode and the second electrode to each other.

An adhesive film storage set according to one aspect of the present invention comprises: the above-mentioned circuit connection adhesive film, and a storage component for storing the adhesive film, wherein the storage component has a viewing portion that allows the interior of the storage component to be visible from the outside, and the transmittance of the viewing portion to light with a wavelength of 365 nm is less than 10%.

However, in general, the environment in which the circuit connection adhesive film is used is called a clean room, and the temperature, humidity, and cleanliness of the room are managed at a certain level. When shipped from the production site, the circuit connection adhesive film is stored in a storage member such as a packaging bag to prevent it from being directly exposed to the outside air and causing quality degradation due to dust and moisture. Usually, a visual recognition portion is provided on the storage member, and the visual recognition portion is formed of a transparent material so that various information such as the product name, batch number, and expiration date attached to the adhesive film inside can be confirmed from the outside of the storage member.

However, according to the research of the present inventors, when the above-mentioned circuit connection adhesive film is used after being stored or transported in an existing storage member, the above-mentioned effect of the adhesive film may not be obtained. Based on this research result, the present inventors further studied and found that when a compound that can react with light and a photopolymerization initiator in a thermosetting composition is used as a polymerizable compound in a thermosetting composition, the thermosetting composition is cured during the storage and transportation of the adhesive film, and the effect of reducing the connection resistance is reduced. Therefore, based on the speculation that the polymerization of the polymerizable compounds in the thermosetting composition is carried out by free radicals originating from the residual photopolymerization initiator in the first adhesive layer, the inventors and others conducted further research and found that by making an adhesive film storage group including the specific storage member, the curing of the thermosetting composition during storage or transportation can be suppressed, and the effect of reducing the connection resistance of the adhesive film can be maintained.

That is, according to the adhesive film storage set of one aspect of the present invention, when a compound that can react with light and a photopolymerization initiator in a thermosetting composition is used as a polymerizable compound in the thermosetting composition, the curing of the thermosetting composition during storage or transportation of the adhesive film can be suppressed, and the effect of reducing the connection resistance of the adhesive film can be maintained. [Effect of the invention]

According to the present invention, a circuit connection adhesive film that can suppress the flow of conductive particles that occurs when manufacturing a circuit connection structure and a method for manufacturing the same can be provided. In addition, according to the present invention, a method for manufacturing a circuit connection structure using the adhesive film can be provided. In addition, according to the present invention, an adhesive film storage set including the adhesive film can be provided.

Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings as appropriate. Furthermore, in this specification, the numerical range represented by "～" represents a range that includes the numerical values recorded before and after "～" as the minimum and maximum values, respectively. In addition, the upper and lower limits recorded individually can be combined arbitrarily. In addition, in this specification, the so-called "(meth)acrylate" refers to at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryl". In addition, the so-called "(poly)" refers to both the case where the prefix "poly" exists and the case where it does not exist.

<Adhesive film for circuit connection> Figure 1 is a schematic cross-sectional view of an adhesive film for circuit connection showing an embodiment. As shown in Figure 1, the adhesive film for circuit connection 1 (hereinafter also referred to as "adhesive film 1") includes a first adhesive layer 2 and a second adhesive layer 3 laminated on the first adhesive layer 2.

(First adhesive layer) The first adhesive layer 2 includes a cured product (photocured product) of a photo- and thermosetting composition. The photo- and thermosetting composition includes (A) a polymerizable compound (hereinafter also referred to as "(A) component"), (B) a photopolymerization initiator (hereinafter also referred to as "(B) component"), (C) a thermal polymerization initiator (hereinafter also referred to as "(C) component"), and (D) conductive particles 4 (hereinafter also referred to as "(D) component").

The first adhesive layer 2 can be obtained, for example, by irradiating a layer containing a photo- and thermosetting composition with light energy to polymerize the (A) component and cure the photo- and thermosetting composition (photocuring). That is, the first adhesive layer 2 includes the conductive particles 4 and the adhesive component 5 obtained by photocuring the photo- and thermosetting composition. The adhesive component 5 includes at least a polymer of the (A) component. The adhesive component 5 may contain unreacted (A) component and (B) component, or may not contain them.

[Component (A): polymerizable compound] Component (A) is a compound that polymerizes by free radicals, cations, or anions generated by a photopolymerization initiator due to irradiation with light (e.g., ultraviolet light). Component (A) may be any of a monomer, an oligomer, or a polymer. As component (A), one compound may be used alone, or a plurality of compounds may be used in combination.

Component (A) has at least one polymerizable group. From the viewpoint of further improving the effect of reducing the connection resistance and improving the connection reliability, the polymerizable group is preferably a free radical polymerizable group that reacts by means of free radicals. That is, component (A) is preferably a free radical polymerizable compound. Examples of free radical polymerizable groups include: vinyl, allyl, styryl, alkenyl, alkenyl, (meth)acryl, maleimide, and the like. Regarding the number of polymerizable groups possessed by component (A), from the viewpoint of easily obtaining the physical properties and crosslinking density required for reducing the connection resistance after polymerization, the number may be more than two, and from the viewpoint of suppressing the curing shrinkage during polymerization, the number may be less than 10. From these viewpoints, the number of polymerizable groups possessed by component (A) may be 2 to 10. In order to obtain a uniform and stable film (first adhesive layer) after light irradiation, it is preferred to suppress the curing shrinkage during polymerization. In this embodiment, in order to achieve a balance between the crosslinking density and the curing shrinkage, in addition to using a polymerizable compound having a polymerizable group within the above range, a polymerizable compound having a polymerizable group outside the above range may also be used.

Specific examples of the component (A) include (meth)acrylate compounds, maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, nadiimide derivatives, natural rubber, isoprene rubber, butyl rubber, nitrile rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, carboxylated nitrile rubber, and the like.

Examples of the (meth)acrylate compound include epoxy (meth)acrylate, (poly)urethane (meth)acrylate, methyl (meth)acrylate, polyether (meth)acrylate, polyester (meth)acrylate, polybutadiene (meth)acrylate, silicone acrylate, ethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 2-(2-ethoxyethoxy) (meth)acrylate ethyl, 2-ethoxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylate ester, ) hexyl acrylate, 2-hydroxyethyl (meth)acrylate, isopropyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobutyl (meth)acrylate, isobornyl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, n-lauryl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-(meth)acryloyloxyethyl phosphate, N,N-dimethylamino (meth)acrylate Ethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trihydroxymethylpropane tri(meth)acrylate, tetrahydroxymethylmethane tetra(meth)acrylate, polyethylene glycol di(meth)acrylate, polyalkylene glycol di(meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol (meth)acrylate, dipentaerythritol hexa(meth)acrylate The invention also includes but is not limited to: 2-(4-(acryloyloxymethoxy)phenyl)propane, 2-(4-(acryloyloxypolyethoxy)phenyl)propane, 2,2-bis(meth)acryloyloxydiethyl phosphate, and 2-(meth)acryloyloxyethyl acid phosphate.

Examples of maleimide compounds include 1-methyl-2,4-dimaleimide benzene, N,N'-m-phenylenedimaleimide, N,N'-p-phenylenedimaleimide, N,N'-m-toluenedimaleimide, N,N'-4,4-biphenylenedimaleimide, N,N'-4,4-(3,3'-dimethyl-biphenyl)dimaleimide, N,N'-4,4-(3,3'-dimethyldiphenylmethane)dimaleimide, N,N'-4,4-(3,3'-diethyldiphenylmethane)dimaleimide, N,N'-4,4-diphenylmethanedimaleimide, N,N '-4,4-diphenylpropane bismaleimide, N,N'-4,4-diphenyl ether bismaleimide, N,N'-3,3-diphenylsulfone bismaleimide, 2,2-bis(4-(4-maleimide phenoxy)phenyl)propane, 2,2-bis(3-sec-butyl-4-8(4-maleimide phenoxy)phenyl)propane, 1,1-bis(4-(4-maleimide phenoxy)phenyl)decane, 4,4'-cyclohexylene-bis(1-(4-maleimide phenoxy)-2-cyclohexyl)benzene, 2,2'-bis(4-(4-maleimide phenoxy)phenyl)hexafluoropropane, etc.

Examples of the vinyl ether compound include diethylene glycol divinyl ether, dipropylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, and trihydroxymethylpropane trivinyl ether.

As the allyl compound, 1,3-diallyl phthalate, 1,2-diallyl phthalate, triallyl isocyanurate, etc. can be listed.

From the perspective of an excellent balance between the curing reaction speed and the physical properties after curing, component (A) is preferably a (meth)acrylate compound. From the perspective of having both cohesive force for reducing the connection resistance and elongation for improving the adhesion to obtain better adhesion properties, component (A) may be a (poly)urethane (meth)acrylate compound. In addition, from the perspective of improving cohesive force and further reducing the connection resistance, component (A) may be a (meth)acrylate compound having a high Tg skeleton such as a dicyclopentadiene skeleton.

From the perspective of achieving a balance between crosslinking density and curing shrinkage, further reducing connection resistance, and improving connection reliability, component (A) may be a compound (e.g., polyurethane (meth)acrylate) having a polymerizable group such as vinyl, allyl, or (meth)acryloyl introduced into the terminal or side chain of a thermoplastic resin such as an acrylic resin, a phenoxy resin, or a polyurethane resin. In this case, from the perspective of achieving an excellent balance between crosslinking density and curing shrinkage, the weight average molecular weight of component (A) may be 3,000 or more, 5,000 or more, or 10,000 or more. In addition, from the perspective of excellent compatibility with other components, the weight average molecular weight of component (A) may be 1,000,000 or less, 500,000 or less, or 250,000 or less. From these viewpoints, the weight average molecular weight of component (A) may be 3,000 to 1,000,000, 5,000 to 500,000, or 10,000 to 250,000. The weight average molecular weight refers to a value measured by gel permeation chromatograph (GPC) under the conditions described in the Examples using a calibration curve obtained from standard polystyrene.

As the (meth)acrylate compound, component (A) is preferably a radical polymerizable compound having a phosphate structure represented by the following formula (1). In this case, the bonding strength to the surface of an inorganic substance (metal, etc.) is improved, so it is suitable for bonding between electrodes (for example, between circuit electrodes). [Chemistry 4]

In formula (1), n represents an integer of 1 to 3, and R represents a hydrogen atom or a methyl group.

The radical polymerizable compound having a phosphate structure can be obtained, for example, by reacting anhydrous phosphoric acid with 2-hydroxyethyl (meth)acrylate. Specific examples of the radical polymerizable compound having a phosphate structure include mono(2-(meth)acryloyloxyethyl) acid phosphate, di(2-(meth)acryloyloxyethyl) acid phosphate, and the like.

From the viewpoint of easily obtaining the cross-linking density required for reducing connection resistance and improving connection reliability, the content of component (A) may be 5% by mass or more, 10% by mass or more, or 20% by mass or more, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition. From the viewpoint of suppressing curing shrinkage during polymerization, the content of component (A) may be 90% by mass or less, 80% by mass or less, or 70% by mass or less, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition. From these viewpoints, the content of component (A) may be 5% to 90% by mass, 10% to 80% by mass, or 20% to 70% by mass, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition.

[Component (B): Photopolymerization initiator] Component (B) is a photopolymerization initiator (photoradical polymerization initiator, photocationic polymerization initiator or photoanionic polymerization initiator) that generates free radicals, cations or anions by irradiation with light having a wavelength in the range of 150 nm to 750 nm, preferably light having a wavelength in the range of 254 nm to 405 nm, and more preferably light having a wavelength of 365 nm (e.g., ultraviolet light). Component (B) is preferably a photoradical polymerization initiator from the viewpoint of easier curing at low temperature and in a short time. As component (B), one compound may be used alone or a plurality of compounds may be used in combination.

The photoradical polymerization initiator is decomposed by light to generate free radicals. That is, the photoradical polymerization initiator is a compound that generates free radicals by applying light energy from the outside. As the photoradical polymerization initiator, there can be listed photopolymerization initiators having structures such as oxime ester structure, bisimidazole structure, acridine structure, α-aminophenyl alkyl ketone structure, aminobenzophenone structure, N-phenylglycine structure, acylphosphine oxide structure, benzyl dimethyl ketal structure, and α-hydroxyphenyl alkyl ketone structure.

As component (B), from the viewpoint of further improving the flow suppression effect and the peeling suppression effect of the conductive particles, it is preferable to use a photopolymerization initiator having a structure represented by the following formula (I). The photopolymerization initiator may have a plurality of structures represented by the following formula (I). [Chemistry 5]

The structure represented by the formula (I) may be an oxime ester structure, a biimidazole structure, or an acridine structure. That is, the photo- and thermosetting composition may contain a photopolymerization initiator having at least one structure selected from the group consisting of an oxime ester structure, a biimidazole structure, and an acridine structure as the structure represented by the formula (I). Among these, from the viewpoint of further improving the flow suppression effect and the peeling suppression effect of the conductive particles, it is preferred to use a photopolymerization initiator having an oxime ester structure.

As the compound having an oxime ester structure, a compound having a structure represented by the following formula (VI) is preferably used.

In formula (VI), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an organic group containing an aromatic hydrocarbon group.

Specific examples of the compound having an oxime ester structure include 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 1,3-dimethoxycarbonyloxime, Phenylpropanetrione-2-(o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl) oxime, 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(o-benzoyl oxime)], ethyl ketone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, 1-(o-acetyl oxime), etc.

Examples of compounds having a biimidazole structure include 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-phenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer.

Examples of the compound having an acridine structure include 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane.

From the viewpoint of further improving the effect of suppressing the flow of conductive particles, the content of the photopolymerization initiator having the structure represented by the formula (I) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, further preferably 0.45% by mass or more, particularly preferably 0.55% by mass or more, and extremely preferably 0.85% by mass or more, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition. From the viewpoint of further improving the effect of suppressing the peeling, the content of the photopolymerization initiator having the structure represented by the formula (I) is preferably 1.2% by mass or less, more preferably 0.9% by mass or less, and further preferably 0.6% by mass or less, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition. From these viewpoints, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition, the content of the photopolymerization initiator having the structure represented by the formula (I) is preferably 0.1 mass % to 1.2 mass %, more preferably 0.3 mass % to 1.2 mass %, further preferably 0.45 mass % to 0.9 mass %, and particularly preferably 0.45 mass % to 0.6 mass %.

From the viewpoint of further improving the effect of suppressing the flow of conductive particles, the content of component (B) (total content of photopolymerization initiators) is preferably 0.3 mass % or more, more preferably 0.45 mass % or more, further preferably 0.55 mass % or more, and particularly preferably 0.85 mass % or more, based on the total amount of components other than conductive particles in the photo- and thermosetting composition. From the viewpoint of further improving the effect of suppressing the peeling, the content of component (B) is preferably 1.2 mass % or less, more preferably 0.9 mass % or less, and further preferably 0.6 mass % or less, based on the total amount of components other than conductive particles in the photo- and thermosetting composition. From these viewpoints, the content of component (B) is preferably 0.3 to 1.2 mass %, more preferably 0.45 to 0.9 mass %, and further preferably 0.45 to 0.6 mass %, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition.

[Component (C): Thermal polymerization initiator] Component (C) may be a thermal polymerization initiator that generates free radicals, cations, or anions by heat (thermal radical polymerization initiator, thermal cationic polymerization initiator, or thermal anionic polymerization initiator). From the perspective of further improving the effect of reducing connection resistance and improving connection reliability, a thermal radical polymerization initiator is preferred. As component (C), one compound may be used alone, or a plurality of compounds may be used in combination.

The thermal radical polymerization initiator decomposes by heat to generate free radicals. That is, the thermal radical polymerization initiator is a compound that generates free radicals by applying thermal energy from the outside. As the thermal radical polymerization initiator, it can be arbitrarily selected from the existing known organic peroxides and azo compounds. As the thermal radical polymerization initiator, from the viewpoint of further improving the flow inhibition effect and the peeling inhibition effect of the conductive particles, an organic peroxide is preferred, and from the viewpoint of stability, reactivity and compatibility, an organic peroxide having a one-minute half-life temperature of 90°C to 175°C and a weight average molecular weight of 180 to 1000 is more preferred. With the one-minute half-life temperature in this range, the storage stability is better and the free radical polymerization is high enough to harden in a short time.

Specific examples of the component (C) include 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, cumyl peroxyneodecanoate, dilauryl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, tert-hexyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, tert-butyl peroxytrimethylacetate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, Ester, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, tert-hexyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyneoheptanoate, tert-pentyl peroxy-2-ethylhexanoate, di-tert-butyl peroxyhexahydrophthalate, tert-pentyl peroxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate, tert-pentyl peroxyneodecanoate, di(3-methylbenzoyl)peroxide ), dibenzoyl peroxide, di(4-methylbenzoyl peroxide), tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxymaleate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxybenzoate Organic peroxides such as tributyl ester, dibutyl peroxytrimethyladipate, t-pentyl peroxyoctanoate, t-pentyl peroxyisononanoate, and t-pentyl peroxybenzoate; azo compounds such as 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis(1-acetyloxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanovaleric acid), and 1,1'-azobis(1-cyclohexanecarbonitrile).

From the viewpoint of excellent rapid curing property and further improvement of the effect of suppressing the flow and peeling of the conductive particles, the content of the component (C) may be 0.1 mass % or more, 0.5 mass % or more, or 1 mass % or more, based on the total amount of components other than the conductive particles in the first adhesive layer. From the viewpoint of pot life, the content of the component (C) may be 20 mass % or less, 10 mass % or less, or 5 mass % or less, based on the total mass of the first adhesive layer or the total amount of components other than the conductive particles in the first adhesive layer. From these viewpoints, the content of the component (C) may be 0.1% by mass to 20% by mass, 0.5% by mass to 10% by mass, or 1% by mass to 5% by mass, based on the total amount of components other than the conductive particles in the first adhesive layer. Furthermore, the content of the component (C) based on the total amount of components other than the conductive particles in the photo- and thermosetting composition may be the same as the above range.

[Component (D): Conductive particles] Component (D) is not particularly limited if it is a particle with conductivity, and may be metal particles containing metals such as Au, Ag, Ni, Cu, solder, etc.; conductive carbon particles containing conductive carbon, etc. Component (D) may also be a coated conductive particle including a core and a coating layer covering the core, wherein the core includes non-conductive glass, ceramic, plastic (polystyrene, etc.), etc., and the coating layer includes the metal or conductive carbon. Among these, a coated conductive particle including a core and a coating layer covering the core may be preferably used, wherein the core includes a metal particle or plastic formed of a hot-melt metal, and the coating layer includes a metal or conductive carbon. In this case, the cured product of the photo- and heat-curable composition can be easily deformed by heating or pressurizing, so when the electrodes are electrically connected to each other, the contact area between the electrode and the (D) component can be increased, thereby further improving the conductivity between the electrodes.

The (D) component may be an insulating coated conductive particle including the metal particles, conductive carbon particles or coated conductive particles and an insulating layer, wherein the insulating layer includes an insulating material such as a resin and covers the surface of the particle. If the (D) component is an insulating coated conductive particle, even if the content of the (D) component is high, the surface of the particles is coated with the resin, which can suppress short circuits caused by contact between the (D) components, and can also improve the insulation between adjacent electrode circuits. The (D) component can use one of the various conductive particles described above alone or in combination of two or more.

The maximum particle size of the component (D) needs to be smaller than the minimum interval between electrodes (the shortest distance between adjacent electrodes). From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of the component (D) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of the component (D) may be 50 μm or less, 30 μm or less, or 20 μm or less. From these viewpoints, the maximum particle size of the component (D) may be 1.0 μm to 50 μm, 2.0 μm to 30 μm, or 2.5 μm to 20 μm. In this specification, the particle size of any 300 (pcs) conductive particles is measured by observation using a scanning electron microscope (SEM), and the maximum value obtained is set as the maximum particle size of the (D) component. In addition, when the (D) component has protrusions and is not spherical, the particle size of the (D) component is set to the diameter of the circle circumscribing the conductive particles in the SEM image.

From the perspective of excellent dispersibility and conductivity, the average particle size of the component (D) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the perspective of excellent dispersibility and conductivity, the average particle size of the component (D) may be 50 μm or less, 30 μm or less, or 20 μm or less. From these perspectives, the average particle size of the component (D) may be 1.0 μm to 50 μm, 2.0 μm to 30 μm, or 2.5 μm to 20 μm. In this specification, the particle size of any 300 (pcs) conductive particles is measured by observation using a scanning electron microscope (SEM), and the average value of the obtained particle sizes is set as the average particle size.

In the first adhesive layer 2, the component (D) is preferably uniformly dispersed. From the perspective of easily obtaining a stable connection resistance, the particle density of the component (D) in the first adhesive layer 2 may be 100 pcs/mm2 ^or more, 1000 pcs/ ^mm2 or more, or 2000 pcs/mm2 or ^more . From the perspective of improving the insulation between adjacent electrodes, the particle density of the component (D) in the first adhesive layer ² may be 100,000 pcs/mm2 or less, 50,000 pcs/mm2 ^or less, or 10,000 pcs/ ^mm2 or less. From these viewpoints, the particle density of the component (D) in the first adhesive layer 2 may be 100 pcs/mm ² to 100,000 pcs/mm ² , 1,000 pcs/mm ² to 50,000 pcs/mm ² , or 2,000 pcs/mm ² to 10,000 pcs/mm ² .

From the viewpoint of further improving the conductivity, the content of the component (D) may be 0.1 volume % or more, 1 volume % or more, or 5 volume % or more, based on the total volume of the first adhesive layer. From the viewpoint of easily suppressing short circuits, the content of the component (D) may be 50 volume % or less, 30 volume % or less, or 20 volume % or less, based on the total volume of the first adhesive layer. From these viewpoints, the content of the component (D) may be 0.1 volume % to 50 volume %, 1 volume % to 30 volume %, or 5 volume % to 20 volume %, based on the total volume of the first adhesive layer. The content of the component (D) based on the total volume of the photo- and thermosetting composition may be the same as the above range.

[Other components] The photo- and thermosetting composition may further contain other components in addition to component (A), component (B), component (C) and component (D). Examples of other components include thermoplastic resins, coupling agents, fillers and thermosetting resins. These components may also be contained in the first adhesive layer 2.

Examples of thermoplastic resins include phenoxy resins, polyester resins, polyamide resins, polyurethane resins, polyesterurethane resins, and acrylic rubbers. When the photo- and thermosetting composition contains a thermoplastic resin, the first adhesive layer can be easily formed. In addition, when the photo- and thermosetting composition contains a thermoplastic resin, the stress of the first adhesive layer generated when the photo- and thermosetting composition is cured can be alleviated. In addition, when the thermoplastic resin has a functional group such as a hydroxyl group, the adhesion of the first adhesive layer can be easily improved. The content of the thermoplastic resin may be, for example, 5 mass % or more and 80 mass % or less, and may be 5 mass % to 80 mass % based on the total amount of components other than the conductive particles in the photo- and thermosetting composition.

As coupling agents, there can be listed silane coupling agents having organic functional groups such as (meth)acryl, butyl, amino, imidazole, and epoxy groups; silane compounds such as tetraalkoxysilane; tetraalkoxy titanium ester derivatives, polydialkyl titanium ester derivatives, etc. When the photo- and thermosetting composition contains a coupling agent, the adhesion can be further improved. Regarding the content of the coupling agent, for example, based on the total amount of components other than the conductive particles in the photo- and thermosetting composition, it can be 0.1 mass% or more and 20 mass% or less, and can be 0.1 mass% to 20 mass%.

As fillers, for example, non-conductive fillers (such as non-conductive particles) can be listed. When the light and heat curing composition contains fillers, it can be expected that the connection reliability will be further improved. The filler can be either an inorganic filler or an organic filler. As inorganic fillers, for example, metal oxide particles such as silica particles, alumina particles, silica-alumina particles, titanium dioxide particles, and zirconium oxide particles; inorganic particles such as nitride particles can be listed. As organic fillers, for example, organic particles such as silicone particles, methacrylate-butadiene-styrene particles, acrylic-silicone particles, polyamide particles, and polyimide particles can be listed. These particles can have a uniform structure or a core-shell structure. The maximum diameter of the filler is preferably smaller than the minimum particle diameter of the conductive particles 4. The content of the filler may be, for example, 1 volume % or more and 30 volume % or less, and may be 1 volume % to 30 volume % based on the total volume of the photo- and thermosetting composition.

Thermosetting resins are resins that harden by heat and have at least one thermosetting group. Thermosetting resins are compounds that react with a hardener by heat and thereby crosslink. As the thermosetting resin, a single compound may be used, or a combination of multiple compounds may be used.

From the viewpoint of further improving the effect of reducing connection resistance and improving connection reliability, the thermosetting group may be, for example, an epoxy group, an oxycyclobutane group, or the like.

Specific examples of thermosetting resins include bisphenol-type epoxy resins that are reaction products of epichlorohydrin and bisphenol A, bisphenol F, bisphenol AD, etc.; epoxy novolac resins that are reaction products of epichlorohydrin and phenol novolac, cresol novolac, etc.; naphthalene-based epoxy resins having a skeleton containing a naphthalene ring; and epoxy resins such as various epoxy compounds having two or more glycidyl groups in one molecule, such as glycidyl amine and glycidyl ether.

The content of the thermosetting resin may be 30% by mass or more and 70% by mass or less, and may be 30% by mass to 70% by mass, based on the total amount of components other than the conductive particles in the first adhesive layer.

When the first adhesive layer includes a thermosetting resin, the first adhesive layer may further include a hardener for hardening the thermosetting resin. The hardener is not particularly limited as long as it generates cationic species by heat, and can be appropriately selected according to the purpose. Examples of the hardener include cobalt salts and iodine salts. The content of the hardener may be, for example, 0.1 parts by mass or more and 50 parts by mass or less, and may be 0.1 parts by mass to 50 parts by mass, relative to 100 parts by mass of the thermosetting resin.

The photo- and thermosetting composition may also contain other additives such as a softener, an accelerator, a degradation inhibitor, a colorant, a flame retardant, a switching agent, etc. The content of these additives may be, for example, 0.1 mass % to 10 mass % based on the total amount of components other than the conductive particles in the photo- and thermosetting composition. These additives may also be contained in the first adhesive layer 2.

The first adhesive layer 2 may also contain unreacted component (B). It is speculated that when the adhesive film 1 of the present embodiment is stored and transported in an existing storage member, unreacted component (B) remains in the first adhesive layer 2, and thus a portion of the thermosetting composition in the second adhesive layer 3 is cured during storage and transportation, and the effect of reducing the connection resistance of the adhesive film 1 is reduced. Therefore, when the first adhesive layer 2 contains component (B), the reduction in the effect of reducing the connection resistance can be prevented by storing the adhesive film 1 in a storage member described later.

From the viewpoint of facilitating the capture of the conductive particles 4 between the opposing electrodes and further reducing the connection resistance, the thickness d1 of the first adhesive layer 2 may be greater than 0.1 times, greater than 0.2 times, or greater than 0.3 times the average particle size of the conductive particles 4. From the viewpoint of making it easier to crush the conductive particles when they are sandwiched between the opposing electrodes during hot pressing and further reducing the connection resistance, the thickness d1 of the first adhesive layer 2 may be less than 0.8 times, or less than 0.7 times the average particle size of the conductive particles 4. From these viewpoints, the thickness d1 of the first adhesive layer 2 may be 0.1 to 0.8 times, 0.2 to 0.8 times, or 0.3 to 0.7 times the average particle size of the conductive particles 4. Furthermore, the thickness d1 of the first adhesive layer 2 refers to the thickness of the first adhesive layer located at adjacent conductive particles 4 and the spaced apart portions of the conductive particles 4 .

When the thickness d1 of the first adhesive layer 2 and the average particle size of the conductive particles 4 satisfy the above relationship, for example, as shown in FIG1 , a portion of the conductive particles 4 in the first adhesive layer 2 may protrude from the first adhesive layer 2 to the side of the second adhesive layer 3. In this case, the boundary S between the first adhesive layer 2 and the second adhesive layer 3 is located at the adjacent conductive particles 4 and the separated portion of the conductive particles 4. The above relationship may also be satisfied when the conductive particles 4 in the first adhesive layer 2 do not protrude from the first adhesive layer 2 to the side of the second adhesive layer 3 by providing the boundary S on the conductive particles along the surface of the conductive particles. The conductive particles 4 may not be exposed on the surface 2a of the first adhesive layer 2 which is opposite to the second adhesive layer 3 side, and the surface 2a on the opposite side may be a flat surface.

The relationship between the thickness d1 of the first adhesive layer 2 and the maximum particle size of the conductive particles 4 may be the same as described above. For example, the thickness d1 of the first adhesive layer 2 may be 0.1 to 0.8 times, 0.2 to 0.8 times, or 0.3 to 0.7 times the maximum particle size of the conductive particles 4.

The thickness d1 of the first adhesive layer 2 can be appropriately set according to the electrode height of the circuit component to be bonded, etc. The thickness d1 of the first adhesive layer 2 can be, for example, not less than 0.5 μm and not more than 20 μm, and can be 0.5 μm to 20 μm. Furthermore, when a portion of the conductive particle 4 is exposed from the surface of the first adhesive layer 2 (for example, protruding to the side of the second adhesive layer 3), the shortest distance from the surface 2a of the first adhesive layer 2 opposite to the side of the second adhesive layer 3 to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 located at the adjacent conductive particle 4 and the separation portion of the conductive particle 4 (the distance represented by d1 in FIG. 1) is the thickness of the first adhesive layer 2, and the exposed portion of the conductive particle 4 is not included in the thickness of the first adhesive layer 2. The length of the exposed portion of the conductive particle 4 can be, for example, 0.1 μm or more and 20 μm or less, and can be 0.1 μm to 20 μm.

The thickness of the adhesive layer can be measured by the following method. First, sandwich the adhesive film between two pieces of glass (thickness: about 1 mm). Then, cast a resin composition containing 100 g of bisphenol A epoxy resin (trade name: JER811, manufactured by Mitsubishi Chemical Co., Ltd.) and 10 g of hardener (trade name: Epomount hardener, manufactured by Refine Tec Co., Ltd.). Then, grind the cross section using a grinder, and measure the thickness of each adhesive layer using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-tech Science Co., Ltd.).

(Second adhesive layer) The second adhesive layer 3 includes, for example, a thermosetting composition containing (a) a polymerizable compound (hereinafter also referred to as component (a)) and (b) a thermal polymerization initiator (hereinafter also referred to as component (b)). The thermosetting composition constituting the second adhesive layer 3 is a thermosetting composition that can flow when connecting a circuit, for example, an uncured thermosetting composition.

[Component (a): polymerizable compound] Component (a) is a compound that polymerizes by free radicals, cations, or anions generated by heat from a thermal polymerization initiator. As component (a), the compounds exemplified as component (A) can be used. From the viewpoint of facilitating connection at low temperature and in a short time, further improving the effect of reducing connection resistance, and improving connection reliability, component (a) is preferably a radical polymerizable compound having a radical polymerizable group that reacts by free radicals. Examples of preferred radical polymerizable compounds in component (a) and combinations of preferred radical polymerizable compounds are the same as those of component (A). When component (a) is a radical polymerizable compound and component (B) in the first adhesive layer is a photoradical polymerization initiator, by housing the adhesive film in a housing member described below, there is a tendency to significantly suppress the curing of the thermosetting composition during storage or transportation of the adhesive film.

The component (a) may be any of a monomer, an oligomer, or a polymer. As the component (a), a single compound may be used alone, or a combination of a plurality of compounds may be used. The component (a) may be the same as or different from the component (A).

From the viewpoint of easily obtaining the crosslinking density required for reducing connection resistance and improving connection reliability, the content of component (a) may be 10% by mass or more, 20% by mass or more, or 30% by mass or more, based on the total mass of the thermosetting composition. From the viewpoint of suppressing curing shrinkage during polymerization and obtaining good reliability, the content of component (a) may be 90% by mass or less, 80% by mass or less, or 70% by mass or less, based on the total mass of the thermosetting composition. From these viewpoints, the content of component (a) may be 10% to 90% by mass, 20% to 80% by mass, or 30% to 70% by mass, based on the total mass of the thermosetting composition.

[Component (b): Thermal polymerization initiator] As component (b), the same thermal polymerization initiator as component (C) can be used. As component (b), one compound can be used alone or in combination of multiple compounds. Component (b) is preferably a thermal free radical polymerization initiator. Examples of preferred thermal free radical polymerization initiators in component (b) are the same as those for component (C).

From the viewpoint of further improving the effect of reducing the connection resistance and improving the connection reliability, the content of component (b) may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, based on the total mass of the thermosetting composition. From the viewpoint of the applicable period, the content of component (b) may be 30% by mass or less, 20% by mass or less, or 10% by mass or less, based on the total mass of the thermosetting composition. From these viewpoints, the content of component (b) may be 0.1% by mass to 30% by mass, 0.5% by mass to 20% by mass, or 1% by mass to 10% by mass, based on the total mass of the thermosetting composition.

[Other components] The thermosetting composition may further contain other components in addition to component (a) and component (b). Examples of other components include thermoplastic resins, coupling agents, fillers, softeners, accelerators, degradation inhibitors, colorants, flame retardants, and thixotropic agents. Details of other components are the same as those of other components in the first adhesive layer 2.

The thermosetting composition may contain the thermosetting resin described above in place of components (a) and (b), or in addition to components (a) and (b). In this case, the thermosetting composition may contain a hardener for hardening the thermosetting resin described above. When a thermosetting resin is used in place of components (a) and (b), the content of the thermosetting resin in the thermosetting composition may be, for example, 20% by mass or more and 80% by mass or less, and may be 20% by mass to 80% by mass, based on the total mass of the thermosetting composition. When a thermosetting resin is used in addition to component (a) and component (b), the content of the thermosetting resin in the thermosetting composition may be, for example, 20% by mass or more and 80% by mass or less, or 20% by mass to 80% by mass, based on the total mass of the thermosetting composition. The content of the hardener may be the same as the range described as the content of the hardener in the light and heat curing composition.

The content of the conductive particles 4 in the second adhesive layer 3 may be, for example, 1 mass % or less, or 0 mass %, based on the total mass of the second adhesive layer. The second adhesive layer 3 preferably does not contain the conductive particles 4 .

The thickness d2 of the second adhesive layer 3 can be appropriately set according to the electrode height of the connected circuit component, etc. From the perspective of being able to fully fill the space between the electrodes and seal the electrodes to obtain better connection reliability, the thickness d2 of the second adhesive layer 3 can be greater than 5 μm and less than 200 μm, and can be 5 μm to 200 μm. Furthermore, when a portion of the conductive particle 4 is exposed from the surface of the first adhesive layer 2 (for example, protruding to the side of the second adhesive layer 3), the distance from the surface 3a of the second adhesive layer 3 opposite to the side of the first adhesive layer 2 to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 located at the adjacent conductive particles 4 and the separation portion of the conductive particles 4 (the distance represented by d2 in Figure 1) is the thickness of the second adhesive layer 3.

From the perspective of fully filling the space between the electrodes and sealing the electrodes to obtain better reliability, the ratio of the thickness d1 of the first adhesive layer 2 to the thickness d2 of the second adhesive layer 3 (thickness d1 of the first adhesive layer 2/thickness d2 of the second adhesive layer 3) can be greater than 1 and less than 100.

The thickness of the adhesive film 1 (the total thickness of all layers constituting the adhesive film 1; in FIG. 1 , the total thickness d1 of the first adhesive layer 2 and the thickness d2 of the second adhesive layer 3) may be, for example, 5 μm or more and 200 μm or less, and may be 5 μm to 200 μm.

In the adhesive film 1, the conductive particles 4 are dispersed in the first adhesive layer 2. Therefore, the adhesive film 1 is an anisotropic conductive adhesive film having anisotropic conductivity. The adhesive film 1 is used between a first circuit component having a first electrode and a second circuit component having a second electrode, and the first circuit component and the second circuit component are heat-pressed to electrically connect the first electrode and the second electrode to each other.

Adhesive film 1 can suppress the flow of conductive particles that occurs when manufacturing a circuit connection structure. In addition, adhesive film 1 can suppress the tendency of peeling at the interface between a circuit component and a circuit connection portion formed by the adhesive film that occurs when the circuit connection structure is used in a high temperature and high humidity environment.

As mentioned above, the circuit connection adhesive film of this embodiment has been described, but the present invention is not limited to the above embodiment.

For example, the circuit connection adhesive film may be a two-layer adhesive film including a first adhesive layer and a second adhesive layer, or may be a three-layer adhesive film including a layer other than the first adhesive layer and the second adhesive layer (e.g., a third adhesive layer). The third adhesive layer may be a layer having the same composition as the composition described above with respect to the first adhesive layer or the second adhesive layer, and may be a layer having the same thickness as the thickness described above with respect to the first adhesive layer or the second adhesive layer. For example, the circuit connection adhesive film may further include a third adhesive layer on the surface of the first adhesive layer on the opposite side to the second adhesive layer. That is, the circuit connection adhesive film is formed by laminating, for example, the second adhesive layer, the first adhesive layer, and the third adhesive layer in this order. In this case, for example, the third adhesive layer contains a thermosetting composition like the second adhesive layer.

In addition, the circuit connecting adhesive film of the above-described embodiment is an anisotropic conductive adhesive film having anisotropic conductivity, but the circuit connecting adhesive film may also be a conductive adhesive film not having anisotropic conductivity.

<Method for manufacturing adhesive film for circuit connection> The method for manufacturing the adhesive film for circuit connection 1 of the present embodiment includes, for example: a preparation step of preparing the first adhesive layer 2 described above (first preparation step); and a lamination step of laminating the second adhesive layer 3 described above on the first adhesive layer 2. The method for manufacturing the adhesive film for circuit connection 1 may also further include: a preparation step of preparing the second adhesive layer 3 (second preparation step).

In the first preparation step, for example, the first adhesive layer 2 is formed on the substrate to obtain a first adhesive film, thereby preparing the first adhesive layer 2. Specifically, first, the components (A), (B), (C), and (D), as well as other components added as needed, are added to an organic solvent, and dissolved or dispersed by stirring, mixing, kneading, etc. to prepare a varnish composition (a varnish of a light- and heat-curable composition). Then, the varnish composition is applied to the substrate subjected to a demolding treatment using a doctor blade coater, a roller coater, an applicator, a notched wheel coater, a die coater, etc., and then the organic solvent is volatilized by heating, thereby forming a layer containing a light- and heat-curable composition on the substrate. Next, the layer containing the photo- and heat-curable composition is irradiated with light to cure the photo- and heat-curable composition (photocuring), thereby forming a first adhesive layer 2 on the substrate (curing step). Thus, a first adhesive film is obtained.

The organic solvent used in the preparation of the varnish composition is preferably one that has the property of dissolving or dispersing each component uniformly, and examples thereof include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, etc. These organic solvents may be used alone or in combination of two or more. The stirring, mixing and kneading during the preparation of the varnish composition may be performed using, for example, a stirrer, an attritor, a three-roll mill, a ball mill, a bead mill or a homogenizer.

The substrate is not particularly limited as long as it has heat resistance that can withstand the heating conditions for volatilizing the organic solvent. For example, substrates (such as films) including oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, etc. can be used.

The heating conditions for volatilizing the organic solvent from the varnish composition applied to the substrate are preferably set to conditions that allow the organic solvent to fully volatilize. The heating conditions may be, for example, 40° C. to 120° C. and 0.1 minute to 10 minutes.

In the light irradiation in the curing step, it is preferred to use irradiation light (e.g., ultraviolet light) in the wavelength range of 150 nm to 750 nm. The light irradiation can be performed using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, a light-emitting diode (LED) light source, etc. The light irradiation amount is not particularly limited, and for example, the cumulative light amount of light with a wavelength of 365 nm can be 100 mJ/ ^cm2 or more, 200 mJ/cm2 ^or more, or 300 mJ/ ^cm2 or more. The irradiation amount of light, for example, can be 10000 mJ/cm ² or less, 5000 mJ/cm ² or less, or 3000 mJ/cm ² or less in terms of the cumulative amount of light having a wavelength of 365 nm.

In the second preparation step, the second adhesive layer 3 is formed on the substrate in the same manner as in the first preparation step except that the components (a) and (b) and other components added as needed are used and light irradiation is not performed to obtain a second adhesive film, thereby preparing the second adhesive layer 3.

In the lamination step, the second adhesive layer 3 may be laminated on the first adhesive layer 2 by laminating the first adhesive film and the second adhesive film, or a varnish composition (a varnish of a thermosetting composition) obtained by using the components (a) and (b) and other components added as needed is applied on the first adhesive layer 2, and the organic solvent is volatilized to laminate the second adhesive layer 3 on the first adhesive layer 2. The lamination step may also be performed in the middle of the first preparation step. For example, after forming a layer containing a light- and heat-curable composition, a lamination step may be performed to obtain a laminate including a layer containing a light- and heat-curable composition (precursor of the first adhesive layer 2) and a layer containing a heat-curable composition (second adhesive layer 3). In this case, the first preparation step can be completed by irradiating the obtained laminate with light to cure the layer containing a light- and heat-curable composition.

Examples of methods for bonding the first adhesive film and the second adhesive film include heat pressing, roll lamination, vacuum lamination, etc. Lamination can be performed at a temperature of 0°C to 80°C, for example.

<Circuit connection structure and its manufacturing method> Hereinafter, a circuit connection structure and its manufacturing method using the above-mentioned circuit connection adhesive film 1 as a circuit connection material will be described.

Fig. 2 is a schematic cross-sectional view of a circuit connection structure according to an embodiment. As shown in Fig. 2, the circuit connection structure 10 includes: a first circuit component 13 having a first circuit substrate 11 and a first electrode 12 formed on a main surface 11a of the first circuit substrate 11; a second circuit component 16 having a second circuit substrate 14 and a second electrode 15 formed on a main surface 14a of the second circuit substrate 14; and a circuit connection portion 17 disposed between the first circuit component 13 and the second circuit component 16 to electrically connect the first electrode 12 and the second electrode 15 to each other.

The first circuit component 13 and the second circuit component 16 may be the same or different from each other. The first circuit component 13 and the second circuit component 16 may be a glass substrate or a plastic substrate with electrodes, a printed wiring board, a ceramic wiring board, a flexible wiring board, a semiconductor integrated circuit (IC) chip, etc. The first circuit substrate 11 and the second circuit substrate 14 may be formed of inorganic materials such as semiconductors, glass, and ceramics, organic materials such as polyimide and polycarbonate, and glass/epoxy composites. The first electrode 12 and the second electrode 15 may be formed of gold, silver, tin, ruthenium, rhodium, palladium, zirconium, iridium, platinum, copper, aluminum, molybdenum, titanium, indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc. The first electrode 12 and the second electrode 15 may be circuit electrodes or bump electrodes. At least one of the first electrode 12 and the second electrode 15 may be a bump electrode. In FIG. 2 , the second electrode 15 is a bump electrode.

The circuit connection portion 17 includes the hardened material of the adhesive film 1 described above. The circuit connection portion 17 includes, for example: a first region 18, located on the first circuit component 13 side in the direction in which the first circuit component 13 and the second circuit component 16 face each other (hereinafter referred to as the "facing direction"), and includes a hardened material of components other than the conductive particles 4 of the light and heat curable composition described above; a second region 19, located on the second circuit component 16 side in the facing direction, and includes a hardened material of the heat curable composition described above; and the conductive particles 4, at least between the first electrode 12 and the second electrode 15 to electrically connect the first electrode 12 and the second electrode 15 to each other. The circuit connection portion may not have two regions like the first region 18 and the second region 19, and may include, for example, a cured product of a component other than the conductive particles 4 of the above-mentioned photo- and thermosetting composition and a cured product of the above-mentioned thermosetting composition mixed therewith.

Fig. 3 is a schematic cross-sectional view showing a method for manufacturing the circuit connection structure 10. As shown in Fig. 3, the method for manufacturing the circuit connection structure 10 includes, for example, the following steps: interposing the adhesive film 1 described above between a first circuit component 13 having a first electrode 12 and a second circuit component 16 having a second electrode 15, and hot-pressing the first circuit component 13 and the second circuit component 16 to electrically connect the first electrode 12 and the second electrode 15 to each other.

Specifically, as shown in FIG. 3( a ), first, a first circuit component 13 having a first circuit substrate 11 and a first electrode 12 formed on a main surface 11 a of the first circuit substrate 11 , and a second circuit component 16 having a second circuit substrate 14 and a second electrode 15 formed on a main surface 14 a of the second circuit substrate 14 are prepared.

Next, the first circuit component 13 and the second circuit component 16 are arranged so that the first electrode 12 and the second electrode 15 face each other, and the adhesive film 1 is arranged between the first circuit component 13 and the second circuit component 16. For example, as shown in FIG. 3 (a), the adhesive film 1 is pressed onto the first circuit component 13 so that the first adhesive layer 2 side faces the mounting surface 11a of the first circuit component 13. Next, the second circuit component 16 is arranged on the first circuit component 13 on which the adhesive film 1 is pressed so that the first electrode 12 on the first circuit substrate 11 and the second electrode 15 on the second circuit substrate 14 face each other.

Furthermore, as shown in FIG3(b), the first circuit component 13 and the second circuit component 16 are pressurized in the thickness direction while the first circuit component 13, the adhesive film 1, and the second circuit component 16 are heated, thereby thermally pressing the first circuit component 13 and the second circuit component 16. At this time, as shown by the arrow in FIG3(b), the second adhesive layer 3 contains an uncured thermosetting composition that can flow, and flows in a manner that fills the gaps between the second electrodes 15 and the second electrodes 15, and is cured by the above heating. Thus, the first electrode 12 and the second electrode 15 are electrically connected to each other via the conductive particles 4, and the first circuit component 13 and the second circuit component 16 are connected to each other, thereby obtaining the circuit connection structure 10 shown in FIG. 2 . In the manufacturing method of the circuit connection structure 10 of the present embodiment, since the first adhesive layer 2 is a pre-hardened layer, the conductive particles 4 are fixed in the first adhesive layer 2. In addition, the first adhesive layer 2 hardly flows during the thermal pressing, and the conductive particles are efficiently captured between the facing electrodes, so the connection resistance between the facing electrodes 12 and 15 is reduced. Therefore, a circuit connection structure with excellent connection reliability is obtained.

<Adhesive film storage group> Figure 4 is a three-dimensional diagram of an adhesive film storage group of an embodiment. As shown in Figure 4, the adhesive film storage group 20 includes: an adhesive film 1 for circuit connection, a reel 21 on which the adhesive film 1 is wound, and a storage member 22 for storing the adhesive film 1 and the reel 21.

As shown in FIG4 , the adhesive film 1 is, for example, in a strip shape. The strip-shaped adhesive film 1 is, for example, produced by cutting a sheet of a whole sheet into strips according to the width of the application. A substrate may be provided on one surface of the adhesive film 1. As the substrate, the substrate such as the PET film described above may be used.

The reel 21 includes a first side plate 24 having a core 23 around which the agent film 1 is wound, and a second side plate 25 disposed to face the first side plate 24 with the core 23 interposed therebetween.

The first side plate 24 is, for example, a circular plate made of plastic, and an opening with a circular cross-section is disposed at a central portion of the first side plate 24 .

The core 23 of the first side plate 24 is a portion around which the adhesive film 1 is wound. The core 23 is made of plastic, for example, and is formed into a ring shape having a thickness equal to the width of the adhesive film 1. The core 23 is fixed to the inner surface of the first side plate 24 in a manner surrounding the opening of the first side plate 24. In addition, an axial hole 26 is provided in the central portion of the reel 21 as a portion for inserting a rotating shaft of a winding device or an output device (not shown). When the rotating shaft is driven with the rotating shaft of the winding device or the output device inserted into the axial hole 26, the reel 21 rotates without idling. A desiccant storage container for storing desiccant may also be embedded in the axial hole 26.

The second side plate 25 is similar to the first side plate 24 , and is a circular plate made of plastic, for example. An opening having a circular cross-section and the same diameter as that of the opening of the first side plate 24 is provided at the center of the second side plate 25 .

The storage member 22 is, for example, in a bag shape, and stores the adhesive film 1 and the reel 21 . The storage member 22 has an insertion port 27 for storing (inserting) the adhesive film 1 and the reel 21 inside the storage member 22 .

The storage member 22 has a viewing portion 28 that allows the interior of the storage member 22 to be viewed from the outside. The storage member 22 shown in FIG.

The visual portion 28 is transmissive to visible light. For example, when the transmittance of the visual portion 28 to light is measured in the range of wavelengths of 450 nm to 750 nm, there is at least one region between the wavelengths of 450 nm to 750 nm where the average transmittance of light is greater than 30% and the wavelength width is 50 nm. The transmittance of the visual portion 28 to light can be obtained by making a sample of a specified size by cutting the visual portion 28, and measuring the transmittance of the sample to light using an ultraviolet-visible spectrophotometer. The storage component 22 has such a visual portion 28, so that various information such as the product name, batch number, and expiration date attached to the reel 21 inside the storage component 22 can also be confirmed from the outside of the storage component 22. Thereby, it can be expected to prevent the mixing of erroneous products and make the sorting work more efficient.

The transmittance of the visual portion 28 to light of a wavelength of 365 nm is less than 10%. The transmittance of the visual portion 28 to light of a wavelength of 365 nm is less than 10%, so that the curing of the thermosetting composition caused by light incident from the outside of the housing component 22 to the inside and the residual photopolymerization initiator in the first adhesive layer 2 can be suppressed. As a result, the effect of reducing the connection resistance of the adhesive film 1 can be maintained, and when the adhesive film 1 is used to connect circuit components to each other, the connection resistance between the electrodes facing each other can be reduced. From the viewpoint of further suppressing the generation of free radicals from the photopolymerization initiator, the transmittance of the visual portion 28 to light of a wavelength of 365 nm is preferably less than 10%, more preferably less than 5%, further preferably less than 1%, and particularly preferably less than 0.1%.

From the same viewpoint, the maximum value of the transmittance of the visual portion 28 to light in a wavelength region in which free radicals, cations or anions can be generated from the photopolymerization initiator (component (B)) is preferably 10% or less, more preferably 5% or less, further preferably 1% or less, and particularly preferably 0.1% or less. Specifically, the maximum value of the transmittance of the visual portion 28 to light in a wavelength range of 254 nm to 405 nm is preferably 10% or less, more preferably 5% or less, further preferably 1% or less, and particularly preferably 0.1% or less.

The visual portion 28 (housing component 22) is formed, for example, by a sheet having a thickness of 10 μm to 5000 μm. The sheet includes a material whose transmittance of the visual portion 28 to light of a wavelength of 365 nm is less than 10%. Such a material may contain one component or may contain a plurality of components. Examples of such a material include low-density polyethylene, linear low-density polyethylene, polycarbonate, polyester, polyacrylate, polyamide, glass, and the like. These materials may also contain ultraviolet absorbers. The visual portion 28 may also have a laminated structure formed by a plurality of layers having different laminated light transmittances. In this case, each layer constituting the visual portion 28 may contain the materials described above.

In order to prevent the intrusion of air from the outside during storage, the insertion port 27 can be sealed by, for example, using a sealing machine. In this case, it is preferable to remove the air in the storage member 22 by suction before sealing the insertion port 27. It can be expected that the moisture in the storage member 22 will decrease from the initial stage of storage, and the entry of air from the outside will be prevented. In addition, by the inner surface of the storage member 22 being in close contact with the reel 21, the friction between the inner surface of the storage member 22 and the surface of the reel 21 due to vibration during transportation can be prevented to generate foreign matter, and scratches on the outer surfaces of the side plates 24 and 25 of the reel 21 can be prevented.

In the above-mentioned embodiment, the receiving member is configured in such a way that the entire receiving member becomes the visual recognition portion. In another embodiment, the receiving member may also have a visual recognition portion in a part of the receiving member. For example, the receiving member may have a rectangular visual recognition portion in the approximate center of the side surface of the receiving member. In this case, the portion of the receiving member other than the visual recognition portion may be black, for example, so as not to transmit ultraviolet light and visible light.

In addition, in the embodiment, the shape of the storage member is a bag, and the storage member may also be a box, for example. The storage member is preferably provided with a cut for unsealing. In this case, the unsealing operation during use becomes easier. [Example]

Hereinafter, the present invention will be described in more detail by using embodiments, but the present invention is not limited to the embodiments.

<Synthesis of polyurethane acrylate (UA1)> In a reaction vessel equipped with a stirrer, a thermometer, a reflux cooling tube with a calcium chloride drying tube, and a nitrogen inlet tube, 2500 parts by mass (2.50 mol) of poly(1,6-hexanediol carbonate) (trade name: Duranol T5652, manufactured by Asahi Kasei Chemicals Co., Ltd., number average molecular weight 1000) and 666 parts by mass (3.00 mol) of isophorone diisocyanate (manufactured by Sigma-Aldrich) were uniformly added dropwise over 3 hours. Then, nitrogen was fully introduced into the reaction vessel, and the reaction vessel was heated to 70°C to 75°C to carry out the reaction. Next, 0.53 parts by mass (4.3 mmol) of hydroquinone monomethyl ether (manufactured by Sigma-Aldrich) and 5.53 parts by mass (8.8 mmol) of dibutyltin dilaurate (manufactured by Sigma-Aldrich) were added to the reaction container, and then 238 parts by mass (2.05 mol) of 2-hydroxyethyl acrylate (manufactured by Sigma-Aldrich) was added, and the mixture was reacted at 70°C for 6 hours in an air environment. Thus, polyurethane acrylate (UA1) was obtained. The weight average molecular weight of polyurethane acrylate (UA1) was 15,000. The weight average molecular weight was measured by gel permeation chromatography (GPC) under the following conditions using a calibration curve obtained from standard polystyrene. (Measurement conditions) Apparatus: GPC-8020 manufactured by Tosoh Corporation Detector: RI-8020 manufactured by Tosoh Corporation Column: Gelpack GLA160S+GLA150S manufactured by Hitachi Chemical Co., Ltd. Sample concentration: 120 mg/3 mL Solvent: Tetrahydrofuran Injection volume: 60 μL Pressure: 2.94×10 ⁶ Pa (30 kgf/cm ² ) Flow rate: 1.00 mL/min

<Production of Conductive Particles> A layer containing nickel was formed on the surface of polystyrene particles in a manner such that the layer thickness was 0.2 μm. In this manner, conductive particles having an average particle size of 4 μm, a maximum particle size of 4.5 μm, and a specific gravity of 2.5 were obtained.

<Preparation method of polyester urethane resin> In a stainless steel autoclave with a heater and equipped with a stirrer, a thermometer, a condenser, a vacuum generator and a nitrogen inlet pipe, 48 parts by mass of isophthalic acid and 37 parts by mass of neopentyl glycol are added, and further, 0.02 parts by mass of tetrabutoxytitanium ester as a catalyst is added. Then, the temperature is raised to 220°C under a nitrogen flow, and the mixture is directly stirred for 8 hours. Then, the pressure is reduced to atmospheric pressure (760 mmHg) and cooled to room temperature. A white precipitate is precipitated. Then, the white precipitate is taken out, washed with water, and vacuum dried to obtain polyester polyol. The obtained polyester polyol was fully dried, dissolved in methyl ethyl ketone (MEK), and added to a four-necked flask equipped with a stirrer, a dropping funnel, a reflux cooler, and a nitrogen inlet tube. In addition, 0.05 parts by mass of dibutyltin laurate was added as a catalyst relative to 100 parts by mass of the polyester polyol, and 50 parts by mass of 4,4'-diphenylmethane diisocyanate was dissolved in MEK relative to 100 parts by mass of the polyester polyol and added using a dropping funnel, and stirred at 80°C for 4 hours to obtain the target polyester urethane resin.

<Preparation of varnish of light- and heat-curable composition (varnish composition)> The following components were mixed in the blending amounts (parts by mass) shown in Table 1 to prepare varnishes of light- and heat-curable composition 1 to light- and heat-curable composition 8.

(Polymerizable compound) A1: Dicyclopentadiene diacrylate (trade name: DCP-A, manufactured by Toa Gosei Co., Ltd.) A2: Polyurethane acrylate synthesized as described above (UA1) A3: 2-Methacryloyloxyethyl acid phosphate (trade name: Light Ester) P-2M, manufactured by Kyoei Chemical Co., Ltd.) (Photopolymerization initiator) B1: 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(O-benzoyl oxime)] (Trade name: Irgacure (registered trademark) OXE01, manufactured by BASF) B2: Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, 1-(o-acetyl oxime) (Trade name: Irgacure (registered trademark) OXE02, manufactured by BASF) (Thermal polymerization initiator =Initiator) C1: Benzoyl peroxide (trade name: NYPER BMT-K40, manufactured by NOF Corporation) (Conductive particles) D1: Conductive particles prepared as described above (Thermoplastic resin) E1: Polyester urethane resin synthesized as described above (Coupling agent) F1: 3-Methacryloyloxypropyltrimethoxysilane (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) (Filler) G1: Silica particles (trade name: R104, manufactured by AEROSIL Co., Ltd., average particle size (primary particle size): 12 nm) (Solvent) H1: Methyl ethyl ketone

[Table 1] 1 2 3 4 5 6 7 8 Composition (mass) Polymeric compounds A1 5 5 5 5 5 5 5 5 A2 37.5 37.5 37.5 37.5 37.5 37.5 37.5 37.5 A3 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Photopolymerization initiator B1 0.5 - - - - - 1.25 - B2 - 0.5 0.4 0.3 0.75 1 - - Thermal polymerization initiator C1 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Conductive particles D1 30 30 30 30 30 30 30 30 Thermoplastic resin E1 35 35 35 35 35 35 35 35 Coupling agent F1 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Filling material G1 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Solvent H1 150 150 150 150 150 150 150 150

<Preparation of varnish of thermosetting composition (varnish composition)> As polymerizable compounds a1 to a3, thermal polymerization initiator b1, coupling agent f1, filler g1 and solvent h1, the same polymerizable compounds A1 to A3, thermal polymerization initiator C1, coupling agent F1, filler G1 and solvent H1 in the light and thermosetting composition were used, and the thermoplastic resin e1 used the following components, and these components were mixed in the formulation amounts (mass parts) shown in Table 2 to prepare a varnish of thermosetting composition 1. (Thermoplastic resin) e1: Phenoxy resin (trade name: PKHC, manufactured by Union Carbide Co., Ltd.)

[Table 2] 1 Composition (mass) Polymeric compounds a1 5 a2 27.5 a3 1.5 Thermal polymerization initiator b1 2.5 Thermoplastic resin e1 35 Coupling agent f1 1.0 Filling material g1 2.5 Solvent h1 150

(Example 1) [Preparation of the first adhesive film] A coating device is used to apply a varnish of the photo- and thermosetting composition 1 on a PET film having a thickness of 50 μm. Then, hot air drying is performed at 70°C for 3 minutes to form a layer containing the photo- and thermosetting composition 1 having a thickness (thickness after drying) of 4 μm on the PET film. The thickness here is measured using a contact thickness gauge. Furthermore, if a contact thickness gauge is used, the size of the conductive particles is reflected, and the thickness of the area where the conductive particles exist is measured. Therefore, after laminating the second adhesive layer and preparing a circuit connection adhesive film consisting of two layers, the thickness of the first adhesive layer located at the separation portion of the adjacent conductive particles is measured by the method described below.

Next, the layer containing the light and heat curable composition 1 was irradiated with light using a metal halide lamp at a cumulative light amount of 1500 mJ/ ^cm2 to polymerize the polymerizable compound. In this way, the light and heat curable composition 1 was cured to form a first adhesive layer. Through the above operation, a first adhesive film having a first adhesive layer on the PET film was obtained (thickness of the region where the conductive particles exist: 4 μm). The density of the conductive particles at this time was about 7000 pcs/ ^mm2 .

[Preparation of the second adhesive film] Use a coating device to apply the varnish of the thermosetting composition 1 on a PET film with a thickness of 50 μm. Then, perform hot air drying at 70°C for 3 minutes to form a second adhesive layer (including the layer of the thermosetting composition 1) with a thickness of 8 μm on the PET film. By the above operation, a second adhesive film having a second adhesive layer on the PET film is obtained.

[Preparation of circuit connection adhesive film] The first adhesive film and the second adhesive film are arranged so that their respective adhesive layers face each other, and are heated at 40°C together with the PET film as a base material, and are laminated using a roll press. In this way, a circuit connection adhesive film having a two-layer structure in which the first adhesive layer and the second adhesive layer are laminated is prepared.

The thickness of the first adhesive layer of the produced circuit connection adhesive film was measured by the following method. First, the circuit connection adhesive film was sandwiched between two pieces of glass (thickness: about 1 mm), and a resin composition containing 100 g of bisphenol A epoxy resin (trade name: JER811, manufactured by Mitsubishi Chemical Co., Ltd.) and 10 g of hardener (trade name: Epomount hardener, manufactured by Refine Tec Co., Ltd.) was cast. Then, the cross-section was polished using a grinder, and the thickness of the first adhesive layer located at the separation portion of the adjacent conductive particles was measured using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-tech Science Co., Ltd.). The thickness of the first adhesive layer is 2 μm.

[Production of circuit connection structure] The circuit connection adhesive film produced by the interlayer was connected to a COF (manufactured by FLEXSEED) with a pitch of 25 μm and a glass substrate with a thin film electrode (manufactured by Geomatec) having a thin film electrode (height: 1200 Å) containing amorphous indium tin oxide (ITO) on a glass substrate. The heat and pressure were applied at 170°C and 6 MPa for 4 seconds using a heat press device (heating method: contact heat type, manufactured by Taiyo Machinery Co., Ltd.) to produce a circuit connection structure (connection structure) across a width of 1 mm. Furthermore, during connection, the circuit-connecting adhesive film is disposed on the glass substrate in such a manner that the surface of the first adhesive layer side of the circuit-connecting adhesive film faces the glass substrate.

<Evaluation of circuit connection structure> [Evaluation of particle fluidity] For the obtained circuit connection structure, the particle fluidity of the resin exuded portion of the circuit connection adhesive film was evaluated using a microscope (trade name: ECLIPSE L200, manufactured by Nikon Corporation). Specifically, the produced circuit connection structure was observed from the glass substrate side using a microscope, and the particle state of the portion that exuded outward from the width of the circuit connection adhesive film was evaluated in three stages. The state where the particles hardly moved and there were no particles in the seepage part was evaluated as 1, the state where the particles moved slightly but the connection between the particles was not observed was evaluated as 2, and the state where the particles flowed and the connection between the particles was observed was evaluated as 3.

[Evaluation of connection resistance] For the obtained circuit connection structure, the connection resistance between the electrodes facing each other was measured with a multimeter just after connection and after the high temperature and high humidity test. The high temperature and high humidity test was performed by placing it in a constant temperature and humidity bath at 85°C and 85%RH for 200 hours. The connection resistance was calculated as the average value of the resistance between the electrodes facing each other at 16 locations.

[Peeling evaluation] A microscope (trade name: ECLIPSE L200, manufactured by Nikon Corporation) was used to evaluate whether the circuit connection part of the circuit connection structure after the high temperature and high humidity test was peeled. Specifically, the circuit connection structure produced as described above was observed from the glass substrate side using a microscope, and the peeling state of the glass substrate and the circuit connection adhesive film was evaluated in three stages. The percentage of the circuit connection adhesive film peeling off from the glass substrate in the total area was determined. A was given to those with almost no peeling (the percentage of the peeled portion was less than 5% of the total), B was given to those with a small amount of peeling (the percentage of the peeled portion was more than 5% and less than 20% of the total), and C was given to those with peeling (the percentage of the peeled portion was more than 20% of the total).

(Example 2 to Example 7 and Comparative Example 1) Except that the photo- and thermosetting compositions 2 to 8 were used as the photo- and thermosetting compositions, the circuit connection adhesive film and the circuit connection structure were prepared in the same manner as in Example 1, and the circuit connection structure was evaluated in the same manner as in Example 1. The results are shown in Tables 3 and 4.

[Table 3] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Light and heat curing compositions 1 2 3 4 Connection resistance (Ω) Just after connecting 1.9 1.8 1.7 1.8 After high temperature and high humidity test 2.5 2.3 2.4 2.4 Particle mobility 1 1 1 2 Peel off A A A A

[Table 4] Embodiment 5 Embodiment 6 Embodiment 7 Comparison Example 1 Light and heat curing compositions 5 6 7 8 Connection resistance (Ω) Just after connecting 1.7 1.8 1.6 1.6 After high temperature and high humidity test 2.6 2.5 2.9 2.4 Particle mobility 1 1 1 3 Peel off A B C A

1: Adhesive film for circuit connection 2: First adhesive layer 2a: Surface of the first adhesive layer opposite to the second adhesive layer 3: Second adhesive layer 3a: Surface of the second adhesive layer opposite to the first adhesive layer 4: Conductive particles 5: Adhesive component 10: Circuit connection structure 11: First circuit substrate 11a: Main surface (mounting surface) of the first circuit substrate 12: Circuit electrode (first electrode) 13: First circuit component 14: Second circuit substrate 14a: Main surface of the second circuit substrate 15: Bump electrode (second electrode) 16: Second circuit component 17: Circuit connection part 18: First area 19: Second area 20: Adhesive film storage group 21: Reel 22: Storage component 23: Reel core 24: First side plate 25: Second side plate 26: Shaft hole 27: Insertion port 28: Visual part d1: Thickness (distance) of the first adhesive layer d2: Thickness (distance) of the second adhesive layer S: Boundary between the first adhesive layer and the second adhesive layer

FIG. 1 is a schematic cross-sectional view of an adhesive film for circuit connection according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a circuit connection structure according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a manufacturing step of a circuit connection structure according to an embodiment of the present invention. FIG. 4 is a three-dimensional view of an adhesive film storage group according to an embodiment of the present invention.

1: Adhesive film for circuit connection

2: First adhesive layer

2a: The surface of the first adhesive layer that is opposite to the second adhesive layer

3: Second adhesive layer

3a: The surface of the second adhesive layer opposite to the first adhesive layer

4: Conductive particles

5: Next ingredient

d1: Thickness of the first adhesive layer (distance)

d2: Thickness of the second adhesive layer (distance)

S: The boundary between the first adhesive layer and the second adhesive layer

Claims (12)

A circuit connection adhesive film includes: a first adhesive layer; and a second adhesive layer, which is laminated on the first adhesive layer, wherein the first adhesive layer includes a light-cured material of a light- and heat-curable composition, wherein the light- and heat-curable composition includes a free radical polymerizable compound having a free radical polymerizable group, a photopolymerization initiator, a thermal free radical polymerization initiator, and conductive particles, wherein the light- and heat-curable composition includes at least a (poly)urethane (meth)acrylate compound as the free radical polymerizable compound, and the second adhesive layer includes a heat-curable composition. The circuit connection adhesive film according to claim 1, wherein the radical polymerizable compound contains a radical polymerizable compound having a phosphate structure represented by the following formula (1):

In formula (1), n represents an integer of 1 to 3, and R represents a hydrogen atom or a methyl group. The circuit connection adhesive film as described in claim 1 or claim 2, wherein the thermosetting composition contains a radical polymerizable compound having a radical polymerizable group. The circuit connection adhesive film as described in claim 1 or claim 2, wherein the photopolymerization initiator has a structure represented by the following formula (I):

The adhesive film for circuit connection as described in claim 4, wherein the structure represented by formula (I) is an oxime ester structure, a bisimidazole structure or an acridine structure. The circuit connection adhesive film according to claim 1 or claim 2, wherein the photopolymerization initiator contains a compound having a structure represented by the following formula (VI):

In formula (VI), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an organic group containing an aromatic hydrocarbon group. The circuit connection adhesive film as described in claim 1 or claim 2, wherein the thickness of the first adhesive layer is 0.1 to 0.8 times the average particle size of the conductive particles. A method for manufacturing an adhesive film for circuit connection includes: a preparation step of preparing a first adhesive layer; and a lamination step of laminating a second adhesive layer containing a thermosetting composition on the first adhesive layer, wherein the preparation step includes a step of obtaining the first adhesive layer by irradiating a layer containing a light and thermosetting composition with light to cure the light and thermosetting composition, wherein the light and thermosetting composition contains a radical polymerizable compound having a radical polymerizable group, a photopolymerization initiator, a thermal radical polymerization initiator, and conductive particles, wherein the light and thermosetting composition contains at least a (poly)urethane (meth)acrylate compound as the radical polymerizable compound. A method for manufacturing an adhesive film for circuit connection as described in claim 8, wherein the thermosetting composition contains a free radical polymerizable compound having a free radical polymerizable group. A method for manufacturing an adhesive film for circuit connection as described in claim 8 or claim 9, wherein the thickness of the first adhesive layer is 0.1 to 0.8 times the average particle size of the conductive particles. A method for manufacturing a circuit connection structure, comprising: placing a circuit connection adhesive film as described in any one of claim 1 to claim 7 between a first circuit component having a first electrode and a second circuit component having a second electrode, and hot pressing the first circuit component and the second circuit component to electrically connect the first electrode and the second electrode to each other. An adhesive film storage set, comprising: an adhesive film for circuit connection as described in any one of claim 1 to claim 7, and a storage component for storing the adhesive film, wherein the storage component has a viewing portion that enables the interior of the storage component to be viewed from the outside, and the transmittance of the viewing portion to light with a wavelength of 365nm is less than 10%.

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