JP7264054B2 - Adhesive film for circuit connection, manufacturing method thereof, manufacturing method of circuit connection structure, and adhesive film housing set - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive film for circuit connection, a method for manufacturing the same, a method for manufacturing a circuit connection structure, and an adhesive film containing set.

Conventionally, various adhesive materials are used to make circuit connections. For example, as an adhesive material for connecting a liquid crystal display and a tape carrier package (TCP), connecting a flexible printed wiring board (FPC) and a TCP, or connecting an FPC and a printed wiring board, conductive particles in an adhesive is used as an adhesive film for circuit connection having anisotropic conductivity in which is dispersed. Specifically, the circuit members are adhered to each other by the circuit connection portion formed by the adhesive film for circuit connection, and the electrodes on the circuit members are electrically connected via the conductive particles in the circuit connection portion. By doing so, a circuit connection structure is obtained.

In the field of precision electronic devices in which an adhesive film for circuit connection having anisotropic conductivity is used, the density of circuits is increasing, and the electrode width and electrode spacing are becoming extremely narrow. For this reason, it is not necessarily easy to efficiently capture the conductive particles on the microelectrodes and obtain high connection reliability.

On the other hand, for example, Patent Literature 1 proposes a method of unevenly distributing conductive particles on one side of an anisotropic conductive adhesive sheet to separate the conductive particles from each other.

WO2005/54388

By the way, when a circuit connection structure obtained using a conventional circuit connection adhesive film is left in a high-temperature and high-humidity environment (for example, 85°C and 85% RH), peeling occurs between the circuit member and the circuit connection portion. may occur. Such peeling can cause a decrease in the connection reliability of the circuit connection structure.

Accordingly, the present invention provides a circuit-connecting adhesive film capable of obtaining a circuit-connected structure in which peeling between a circuit member and a circuit-connecting portion is unlikely to occur in a high-temperature and high-humidity environment, a method for producing the same, and the adhesive. An object of the present invention is to provide a method for manufacturing a circuit connection structure using a film, and an adhesive film containing set including the adhesive film.

An adhesive film for circuit connection according to one aspect of the present invention comprises a first adhesive layer containing conductive particles and a second adhesive layer laminated on the first adhesive layer. , the ratio of the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity to the lowest melt viscosity of the second adhesive layer is 10 or more.

According to this adhesive film for circuit connection, it is possible to obtain a circuit connection structure in which peeling between the circuit member and the circuit connection portion is unlikely to occur in a high-temperature and high-humidity environment (for example, 85° C., 85% RH). . In other words, according to this circuit-connecting adhesive film, it is possible to improve the adhesion between the circuit member and the circuit-connecting portion in a high-temperature and high-humidity environment. Furthermore, according to this circuit-connecting adhesive film, it is possible to reduce the connection resistance of the opposing electrodes of the circuit-connecting structure, and the connection resistance is low even in a high-temperature and high-humidity environment (for example, 85° C., 85% RH). resistance can be maintained. That is, according to this adhesive film for circuit connection, the connection reliability of the circuit connection structure can be improved.

A method for producing an adhesive film for circuit connection according to one aspect of the present invention comprises a preparation step of preparing a first adhesive layer; and a lamination step of laminating the adhesive layer of the first curable composition by irradiating or heating the layer made of the first curable composition containing conductive particles. curing the article to obtain a first adhesive layer, the curing step comprising the first adhesive layer at a temperature at which the second adhesive layer exhibits a lowest melt viscosity relative to the lowest melt viscosity of the second adhesive layer; The first curable composition is cured so that the melt viscosity ratio of the adhesive layer is 10 or more. According to this method, it is possible to obtain a circuit-connecting adhesive film that can provide a circuit-connecting structure in which peeling between the circuit member and the circuit-connecting portion is unlikely to occur in a high-temperature, high-humidity environment.

The first adhesive layer may consist of a cured product of the first curable composition, and the first curable composition may contain a radically polymerizable compound having a radically polymerizable group.

The second adhesive layer may consist of a second curable composition, and the second curable composition may contain a radically polymerizable compound having a radically polymerizable group.

The thickness of the first adhesive layer may be 0.2 to 0.8 times the average particle size of the conductive particles.

According to one aspect of the present invention, there is provided a method for manufacturing a circuit connection structure, wherein the circuit connection adhesive described above is placed between a first circuit member having a first electrode and a second circuit member having a second electrode. A step of thermally compressing the first circuit member and the second circuit member with the agent film interposed to electrically connect the first electrode and the second electrode to each other. According to this method, it is possible to obtain a circuit connection structure in which peeling is unlikely to occur between the circuit member and the circuit connection portion in a high-temperature and high-humidity environment.

An adhesive film containing set according to one aspect of the present invention includes the circuit-connecting adhesive film described above and a containing member that contains the adhesive film, and the containing member allows the inside of the containing member to be visually recognized from the outside. and the transmittance of light having a wavelength of 365 nm in the visible portion is 10% or less.

By the way, generally, the environment in which an adhesive film for circuit connection is used is a room called a clean room, in which temperature, humidity and cleanliness are controlled at a constant level. When the circuit-connecting adhesive film is shipped from the production site, the circuit-connecting adhesive film is stored in a packing bag or other container so as not to be directly exposed to the outside air and cause quality deterioration due to dust and moisture. do. Normally, this storage member has a visual indicator made of a transparent material so that various information such as the product name, lot number, and expiration date attached to the adhesive film inside the storage member can be confirmed even from the outside of the storage member. department is provided.

However, when the above-described circuit-connecting adhesive film is housed in a conventional housing member and stored or transported and then used, peeling between the circuit member and the circuit-connecting portion is likely to occur in a high-temperature, high-humidity environment. It has been clarified by the studies of the present inventors that the effect of reducing the connection resistance of the adhesive film may be reduced. As a result of further studies by the present inventors based on such study results, the first adhesive layer is composed of a cured product of a photocurable composition, and the second adhesive layer is composed of the photocurable composition. When the adhesive film is made of a curable composition containing a polymerizable compound that can react with the photopolymerization initiator in the product, the second adhesive layer may harden during storage and transportation of the adhesive film, causing the above problems. It was revealed. Therefore, the present inventors speculated that the polymerization of the polymerizable compound in the second adhesive layer is progressing due to the radicals derived from the photopolymerization initiator remaining in the first adhesive layer. As a result of investigation, it was found that by providing an adhesive film storage set including the specific storage member, hardening of the second adhesive layer during storage or transportation can be suppressed, and occurrence of the above problems can be suppressed. I found what I can do.

That is, according to the adhesive film accommodation set of one aspect of the present invention, when a compound capable of reacting with the photopolymerization initiator in the first adhesive layer is used as the polymerizable compound in the second adhesive layer, , the hardening of the second adhesive layer can be suppressed during storage or transportation of the adhesive film, and peeling between the circuit member and the circuit connection portion is likely to occur in a high-temperature and high-humidity environment. It is possible to suppress the occurrence of problems such as a decrease in the effect of reducing the connection resistance of the agent film.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive film for circuit connection which can obtain the circuit connection structure in which peeling does not occur easily between a circuit member and a circuit connection part in a high-temperature and high-humidity environment, its manufacturing method, and this adhesive. It is possible to provide a method for manufacturing a circuit connection structure using a film, and an adhesive film containing set including the adhesive film.

FIG. 1 is a schematic cross-sectional view showing an adhesive film for circuit connection according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a circuit connection structure according to one embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a manufacturing process of a circuit connection structure according to one embodiment of the present invention. FIG. 4 is a perspective view showing an adhesive film containing set according to one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In addition, in this specification, the upper limit value and the lower limit value described individually can be combined arbitrarily. Moreover, in this specification, "(meth)acrylate" means at least one of acrylate and methacrylate corresponding thereto. The same applies to other similar expressions such as "(meth)acryloyl".

<Adhesive film for circuit connection>
FIG. 1 is a schematic cross-sectional view showing an adhesive film for circuit connection according to one embodiment. As shown in FIG. 1, a circuit-connecting adhesive film 1 (hereinafter also simply referred to as "adhesive film 1") is laminated on a first adhesive layer 2 and the first adhesive layer 2. and a second adhesive layer 3 . The first adhesive layer 2 contains conductive particles 4 .

In the adhesive film 1 , conductive particles 4 are dispersed in the first adhesive layer 2 . Therefore, the adhesive film 1 is an anisotropically conductive adhesive film having anisotropic conductivity. The adhesive film 1 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode to connect the first circuit member and the second circuit member. Thermocompression bonding is used to electrically connect the first electrode and the second electrode to each other.

In the present embodiment, the ratio of the melt viscosity X of the first adhesive layer 2 at the temperature Ty at which the second adhesive layer 3 exhibits the lowest melt viscosity Y to the lowest melt viscosity Y of the second adhesive layer 3 ( X/Y) is 10 or more. Therefore, according to the adhesive film 1, it is possible to obtain a circuit connection structure in which peeling between the circuit member and the circuit connection portion is unlikely to occur in a high-temperature and high-humidity environment (eg, 85° C., 85% RH).

Furthermore, according to the adhesive film 1, the connection resistance of the opposing electrodes of the circuit connection structure can be reduced, and low connection resistance is maintained even in a high-temperature and high-humidity environment (eg, 85° C., 85% RH). can do. That is, according to the adhesive film 1, the connection reliability of the circuit connection structure can be improved. Although the reason why such an effect is obtained is not clear, the present inventors presume that the following two points contribute. The first point is that in the present embodiment, the melt viscosity ratio (X/Y) of the adhesive film 1 is 10 or more, so that the conductive particles 4 are fixed by the first adhesive layer 2, and the conductive particles 4 are not conductive at the time of connection. This is due to the fact that the flow of the particles 4 is suppressed, and as a result, the capture efficiency of the conductive particles 4 at the electrode is improved. The second point is that in the present embodiment, the melt viscosity ratio (X/Y) of the adhesive film 1 is 10 or more. This is a contribution from the fact that it is greatly suppressed compared to the adhesive layer 3 . For example, in the case of a normal adhesive (for example, an adhesive having a two-layer structure), both layers of the laminated two adhesive layers flow and harden at the same time under pressure bonding for a short period of time such as 170° C. for 5 seconds. At this time, at the interface between the adhesive layer and the circuit member, distortion or internal stress is likely to occur because the adhesive constituting the adhesive layer flows and cures. On the other hand, in this embodiment, the second adhesive layer 3 flows and hardens, but the first adhesive layer 2 hardly flows and hardens. Therefore, distortion or internal stress is less likely to occur between the circuit member and the first adhesive layer 2, and the adhesion between the circuit member and the circuit connecting portion can be improved in a high-temperature and high-humidity environment. , the connection reliability can be improved.

In addition, the adhesive film 1 is stored and used as an adhesive reel by slitting the adhesive film 1 formed on one side of the substrate into a narrow width and winding it around a core. may occur. This adhesive reel is required to have good blocking resistance such that the adhesive film 1 is not easily peeled off from the substrate when the adhesive film with the substrate is unwound from the adhesive reel. However, when a conventional adhesive film is slit into a narrow width of about 0.4 to 1.0 mm, it may be difficult to obtain good blocking resistance. On the other hand, since the adhesive film 1 of the present embodiment has a melt viscosity ratio (X/Y) of 10 or more, sticking (blocking) between the first adhesive layer 2 and the substrate is suppressed. Therefore, by providing a substrate on the surface of the second adhesive layer 3 opposite to the first adhesive layer 2, even when slitting to a narrow width as described above, good blocking resistance can be achieved. tends to be obtained. The blocking resistance can be evaluated, for example, by a test to confirm whether or not the adhesive reel can be pulled out without problems after being left in an environment of 30° C. for 24 hours.

The melt viscosity ratio (X/Y) is preferably 10 or more, more preferably 20 or more, still more preferably 50 or more, and particularly preferably, from the viewpoint of improving adhesion to circuit members. is 100 or more. The melt viscosity ratio (X/Y) may be 10,000 or less, 5,000 or less, or 1,000 or less from the viewpoint of wettability to circuit members. From these points of view, the melt viscosity ratio (X/Y) may be from 10 to 10,000, from 20 to 5,000, from 50 to 5,000, or from 100 to 1,000. The melt viscosity X and the minimum melt viscosity Y can be obtained by measuring the melt viscosities of the first adhesive layer 2 and the second adhesive layer 3 by the method described in Examples. Specifically, first, by measuring the melt viscosity of the second adhesive layer 3, the lowest melt viscosity Y of the second adhesive layer 3 (and the temperature Ty at which the second adhesive layer exhibits the lowest melt viscosity Y) is obtained, the melt viscosity X of the first adhesive layer 2 at the temperature Ty is obtained by measuring the melt viscosity of the first adhesive layer 2 . The melt viscosity can also be measured after the adhesive film 1 is obtained.

(First adhesive layer)
The first adhesive layer 2 is made of, for example, a cured product of the first curable composition. The first curable composition may be a photocurable composition, a thermosetting composition, or a mixture of a photocurable composition and a thermosetting composition. The first curable composition includes, for example, (A) a polymerizable compound (hereinafter also referred to as "(A) component"), (B) a polymerization initiator (hereinafter also referred to as "(B) component"). , and (C) conductive particles 4 (hereinafter also referred to as “(C) component”). When the first curable composition is a photocurable composition, the first curable composition contains a photopolymerization initiator as component (B), and the first curable composition is a thermosetting composition is a product, the first curable composition contains a thermal polymerization initiator as component (B). Such a first adhesive layer 2 is formed, for example, by irradiating light or heating a layer made of the first curable composition to polymerize the component (A) to form the first curable composition. obtained by curing the That is, the first adhesive layer 2 may consist of the conductive particles 4 and the adhesive component 5 obtained by curing the components other than the conductive particles 4 of the first curable composition. The first adhesive layer 2 may be a cured product obtained by completely curing the first curable composition, or a cured product obtained by partially curing the first curable composition. good. That is, when the first curable composition contains components (A) and (B), the adhesive component 5 may contain unreacted components (A) and (B), It does not have to be contained. The first adhesive layer 2 may be made of a resin composition other than the cured product of the curable composition. For example, the first adhesive layer may be made of a resin composition containing resin components such as phenoxy resin such as PKHC, polyester urethane resin, polyurethane resin, and acrylic rubber. By using such a resin component, the melt viscosity at the temperature (for example, 100° C.) at which the second adhesive layer exhibits the lowest melt viscosity can be adjusted to about 100,000 to 10,000,000 Pa s, and the melt viscosity ratio ( X/Y) can be 10 or more.

[(A) component: polymerizable compound]
The component (A) is, for example, a compound that is polymerized by radicals, cations, or anions generated by a polymerization initiator (photopolymerization initiator or thermal polymerization initiator) upon irradiation with light (eg, ultraviolet light) or heating. Component (A) may be a monomer, oligomer or polymer. As the component (A), one type of compound may be used alone, or multiple types of compounds may be used in combination.

(A) Component has at least one or more polymerizable groups. A polymerizable group is, for example, a group containing a polymerizable unsaturated double bond (ethylenically unsaturated bond). The polymerizable group further improves the viewpoint that the desired melt viscosity is easily obtained, the viewpoint that peeling between the circuit member and the circuit connection part is unlikely to occur in a high-temperature and high-humidity environment, and the effect of reducing the connection resistance. It is preferably a radically polymerizable group that reacts with radicals, from the viewpoint of more excellent connection reliability. That is, the component (A) is preferably a radically polymerizable compound. Examples of radically polymerizable groups include vinyl groups, allyl groups, styryl groups, alkenyl groups, alkenylene groups, (meth)acryloyl groups, and maleimide groups. The number of polymerizable groups possessed by the component (A) is such that the desired melt viscosity is easily obtained after polymerization, the peeling between the circuit member and the circuit connecting part is unlikely to occur in a high-temperature and high-humidity environment, In addition, it may be 2 or more from the viewpoint of further improving the effect of reducing the connection resistance and more excellent in connection reliability, and may be 10 or less from the viewpoint of suppressing curing shrinkage during polymerization. Moreover, in order to balance the crosslink density and cure shrinkage, a polymerizable compound having the number of polymerizable groups within the above range may be used, and then a polymerizable compound having the number outside the above range may be additionally used.

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

(Meth)acrylate compounds 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) ethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl ( meth)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 - dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane 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, penta Erythritol (meth)acrylate, dipentaerythritol hexa(meth)acrylate, isocyanuric acid-modified bifunctional (meth)acrylate, isocyanuric acid-modified trifunctional (meth)acrylate, tricyclodecanyl acrylate, dimethylol-tricyclodecane diacrylate, 2 -hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane, 2,2 -di(meth)acryloyloxydiethyl phosphate, 2-(meth)acryloyloxyethyl acid phosphate and the like.

Maleimide compounds include 1-methyl-2,4-bismaleimidobenzene, N,N'-m-phenylenebismaleimide, N,N'-p-phenylenebismaleimide, and N,N'-m-toluylenebismaleimide. , N,N′-4,4-biphenylenebismaleimide, N,N′-4,4-(3,3′-dimethyl-biphenylene)bismaleimide, N,N′-4,4-(3,3′ -dimethyldiphenylmethane)bismaleimide, N,N'-4,4-(3,3'-diethyldiphenylmethane)bismaleimide, N,N'-4,4-diphenylmethanebismaleimide, N,N'-4,4- diphenylpropane bismaleimide, N,N'-4,4-diphenylether bismaleimide, N,N'-3,3-diphenylsulfone bismaleimide, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, 2,2-bis(3-s-butyl-4-8(4-maleimidophenoxy)phenyl)propane, 1,1-bis(4-(4-maleimidophenoxy)phenyl)decane, 4,4'-cyclohexyl den-bis(1-(4-maleimidophenoxy)-2-cyclohexylbenzene, 2,2'-bis(4-(4-maleimidophenoxy)phenyl)hexafluoropropane and the like.

Examples of vinyl ether compounds include diethylene glycol divinyl ether, dipropylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, trimethylolpropane trivinyl ether, and the like.

Examples of allyl compounds include 1,3-diallyl phthalate, 1,2-diallyl phthalate, and triallyl isocyanurate.

The component (A) has the viewpoint that the desired melt viscosity is easily obtained, the viewpoint that peeling between the circuit member and the circuit connection part is difficult to occur in a high temperature and high humidity environment, and the effect of reducing the connection resistance is further improved. However, from the viewpoint of better connection reliability, it is preferably a (meth)acrylate compound. The component (A) may be a (poly)urethane (meth)acrylate compound (a urethane (meth)acrylate compound or a polyurethane (meth)acrylate compound) from the viewpoint of obtaining even better adhesive properties. Moreover, the (A) component may be a (meth)acrylate compound having a high Tg skeleton such as a dicyclopentadiene skeleton, from the viewpoint of obtaining even better adhesive properties.

The component (A) has the viewpoint that the desired melt viscosity is easily obtained, the viewpoint that peeling between the circuit member and the circuit connection part is difficult to occur in a high temperature and high humidity environment, and the effect of reducing the connection resistance is further improved. However, from the viewpoint of better connection reliability, a compound ( For example, it may be polyurethane (meth)acrylate). In this case, the weight average molecular weight of component (A) may be 3,000 or more, 5,000 or more, or 10,000 or more from the viewpoint of excellent balance between crosslink density and cure shrinkage. 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 the viewpoint of excellent compatibility with other components. The weight average molecular weight is a value measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve according to the conditions described in Examples.

［式中、ｎは１～３の整数を示し、Ｒは、水素原子又はメチル基を示す。］Component (A) preferably contains, as a (meth)acrylate compound, a radically polymerizable compound having a phosphate ester structure represented by the following general formula (1). In this case, since the adhesive strength to the surface of an inorganic substance (metal etc.) is improved, it is suitable for adhesion between electrodes (for example, circuit electrodes).

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

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

The content of the component (A) is from the viewpoint of easily obtaining the desired melt viscosity, from the viewpoint of preventing peeling between the circuit member and the circuit connection portion in a high-temperature and high-humidity environment, and from the viewpoint of reducing the connection resistance. From the viewpoint of further improving the connection reliability, the total mass of the first curable composition may be 5% by mass or more, may be 10% by mass or more, and may be 20% by mass or more. you can The content of component (A) may be 90% by mass or less, or 80% by mass or less, based on the total mass of the first curable composition, from the viewpoint of suppressing cure shrinkage during polymerization. It may be 70% by mass or less.

[(B) component: polymerization initiator]
Component (B) is radicalized by irradiation with light containing a wavelength within the range of 150 to 750 nm, preferably light containing a wavelength within the range of 254 to 405 nm, more preferably light containing a wavelength of 365 nm (for example, ultraviolet light). , A photopolymerization initiator that generates cations or anions (photoradical polymerization initiator, photocationic polymerization initiator or photoanion polymerization initiator), and a thermal polymerization initiator that generates radicals, cations or anions by heat ( a thermal radical polymerization initiator, a thermal cationic polymerization initiator, or a thermal anionic polymerization initiator). Component (B) is a radical from the viewpoint that the desired melt viscosity is easily obtained, the effect of reducing the connection resistance is further improved, the connection reliability is more excellent, and the curing at a low temperature in a short time becomes easier. A polymerization initiator (radical photopolymerization initiator or thermal radical polymerization initiator) is preferred. As the component (B), one type of compound may be used alone, or a plurality of types of compounds may be used in combination. For example, the first curable composition may contain both a photopolymerization initiator and a thermal polymerization initiator as component (B).

Photoradical polymerization initiators are decomposed by light to generate free radicals. In other words, the radical photopolymerization initiator is a compound that generates radicals upon application of light energy from the outside. Photoradical polymerization initiators include oxime ester structure, bisimidazole structure, acridine structure, α-aminoalkylphenone structure, aminobenzophenone structure, N-phenylglycine structure, acylphosphine oxide structure, benzyldimethylketal structure, α-hydroxy A compound having a structure such as an alkylphenone structure is included. The radical photopolymerization initiator is selected from the group consisting of an oxime ester structure, an α-aminoalkylphenone structure and an acylphosphine oxide structure from the viewpoint of easily obtaining the desired melt viscosity and from the viewpoint of being more excellent in the effect of reducing connection resistance. It is preferred to have at least one structure that is

Specific examples of compounds 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-diphenylpropanetrione- 2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, 1,2-octanedione, 1-[4-(phenylthio)phenyl-,2-( o-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) and the like.

Specific examples of compounds having an α-aminoalkylphenone structure include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1 -morpholinophenyl)-butanone-1 and the like.

Specific examples of compounds having an acylphosphine oxide structure include bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,4,6,-trimethylbenzoyl)- phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like.

Thermal radical polymerization initiators are decomposed by heat to generate free radicals. In other words, the thermal radical polymerization initiator is a compound that generates radicals when thermal energy is applied from the outside. The thermal radical polymerization initiator can be arbitrarily selected from conventionally known organic peroxides and azo compounds. As the thermal radical polymerization initiator, an organic peroxide having a 1-minute half-life temperature of 90 to 175° C. and a weight average molecular weight of 180 to 1000 is preferably used from the viewpoint of stability, reactivity and compatibility. be done. When the 1-minute half-life temperature is in this range, the storage stability is further excellent, the radical polymerizability is sufficiently high, and curing in a short time is possible.

Specific examples of organic peroxides include 1,1,3,3-tetramethylbutylperoxyneodecanoate, di(4-t-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)peroxy Dicarbonate, cumyl peroxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate , t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy) Hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate , di-t-butylperoxyhexahydroterephthalate, t-amylperoxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, t-amylper oxyneodecanoate, t-amylperoxy-2-ethylhexanoate, di(3-methylbenzoyl)peroxide, dibenzoylperoxide, di(4-methylbenzoyl)peroxide, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di(3- methylbenzoylperoxy)hexane, t-butylperoxy-2-ethylhexylmonocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxybenzoate , dibutyl peroxytrimethyl adipate, t-amyl peroxy normal octoate, t-amyl peroxy isononanoate, t-amyl peroxy benzoate and the like.

Specific examples of azo compounds include 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis(1-acetoxy-1-phenylethane), 2,2′-azobisisobutyro nitrile, 2,2'-azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanovaleric acid), 1,1'-azobis(1-cyclohexanecarbonitrile) and the like.

The content of the component (B) is 0.1% by mass or more based on the total mass of the first curable composition, from the viewpoint of excellent rapid curability and the excellent effect of reducing the connection resistance. Well, it may be 0.5% by mass or more. The content of the component (B) may be 15% by mass or less based on the total mass of the first curable composition, from the viewpoint of improving the storage stability and from the viewpoint of being excellent in the effect of reducing the connection resistance. , 10% by mass or less, and may be 5% by mass or less.

From the viewpoint of easily obtaining the desired viscosity, the first curable composition preferably contains at least one of a photopolymerization initiator and a thermal polymerization initiator as the component (B). From the viewpoint of facilitating the production of the agent film, it is more preferable to contain a photopolymerization initiator.

[(C) component: conductive particles]
Component (C) is not particularly limited as long as it is particles having conductivity, such as metal particles composed of metals such as Au, Ag, Ni, Cu, solder, and conductive carbon particles composed of conductive carbon. can be Component (C) is a coated conductive particle comprising a nucleus containing non-conductive glass, ceramic, plastic (such as polystyrene), etc., and a coating layer containing the above metal or conductive carbon and covering the nucleus. good. Among these, coated conductive particles comprising a core containing metal particles made of a heat-fusible metal or plastic and a coating layer containing metal or conductive carbon and covering the core are preferably used. In this case, since it is easy to deform the cured product of the first curable composition by heating or pressing, when the electrodes are electrically connected to each other, the contact area between the electrodes and the component (C) is can be increased to further improve the conductivity between the electrodes.

Component (C) is an insulating coated conductive particle comprising the above metal particles, conductive carbon particles, or coated conductive particles, and an insulating material such as a resin, and an insulating layer covering the surface of the particles. good. When the component (C) is an insulating coating conductive particle, even if the content of the component (C) is large, the surface of the particle is coated with a resin, so the short circuit due to the contact between the components (C) The occurrence can be suppressed, and the insulation between adjacent electrode circuits can be improved. (C) component is used individually by 1 type in the various electroconductive particles mentioned above, or in combination of 2 or more types.

The maximum particle size of component (C) must be smaller than the minimum distance between electrodes (the shortest distance between adjacent electrodes). The maximum particle size of component (C) 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 component (C) may be 50 µm or less, 30 µm or less, or 20 µm or less from the viewpoint of excellent dispersibility and conductivity. In this specification, for 300 arbitrary conductive particles (pcs), the particle size is measured by observation using a scanning electron microscope (SEM), and the largest value obtained is the maximum particle size of the component (C) and When the component (C) is not spherical, such as when the component (C) has projections, the particle size of the component (C) is the diameter of a circle circumscribing the conductive particles in the SEM image.

The average particle diameter of component (C) 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 average particle size of component (C) may be 50 µm or less, 30 µm or less, or 20 µm or less from the viewpoint of excellent dispersibility and conductivity. In this specification, 300 arbitrary conductive particles (pcs) are observed with a scanning electron microscope (SEM) to measure the particle size, and the average value of the obtained particle sizes is defined as the average particle size.

Component (C) is preferably dispersed uniformly in the first adhesive layer 2 . From the viewpoint of obtaining stable connection resistance, the particle density of the component (C) in the first adhesive layer 2 may be 100 pcs/mm ² or more, 1000 pcs/mm ² or more, and 2000 pcs/mm. It may be ² or more. The particle density of the component (C) in the first adhesive layer 2 may be 100,000 pcs/mm ² or less, or 50,000 pcs/mm ² or less, from the viewpoint of improving insulation between adjacent electrodes. It may be 10000 pcs/mm ² or less.

From the viewpoint of further improving conductivity, the content of component (C) may be 0.1% by volume or more, or 1% by volume or more, based on the total volume in the first adhesive layer. may be present, and may be 5% by volume or more. From the viewpoint of easily suppressing short circuits, the content of component (C) may be 50% by volume or less, 30% by volume or less, or 20% by volume, based on the total volume in the first adhesive layer. % or less. The content of component (C) in the first curable composition (based on the total volume of the first curable composition) may be the same as the above range.

[Other ingredients]
The first curable composition may further contain components other than components (A), (B) and (C). Other components include, for example, thermoplastic resins, coupling agents and fillers. These components may be contained in the first adhesive layer 2 .

Examples of thermoplastic resins include phenoxy resins, polyester resins, polyamide resins, polyurethane resins, polyester urethane resins, and acrylic rubbers. When the first curable composition contains a thermoplastic resin, the first adhesive layer can be easily formed. Moreover, when the first curable composition contains a thermoplastic resin, the stress in the first adhesive layer generated during curing of the first curable composition can be relaxed. Moreover, when the thermoplastic resin has a functional group such as a hydroxyl group, the adhesiveness of the first adhesive layer is likely to be improved. The content of the thermoplastic resin may be, for example, 5% by mass or more and 80% by mass or less based on the total mass of the first curable composition.

Coupling agents include silane coupling agents having organic functional groups such as (meth)acryloyl groups, mercapto groups, amino groups, imidazole groups and epoxy groups, silane compounds such as tetraalkoxysilanes, tetraalkoxytitanate derivatives, polydialkyl titanate derivatives and the like. Adhesion can be further improved when the first curable composition contains a coupling agent. The content of the coupling agent may be, for example, 0.1% by mass or more and 20% by mass or less based on the total mass of the first curable composition.

Fillers include, for example, non-conductive fillers (eg, non-conductive particles). When the first curable composition contains a filler, further improvement in connection reliability can be expected. The filler may be either an inorganic filler or an organic filler. Examples of inorganic fillers include metal oxide fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles and zirconia fine particles; and inorganic fine particles such as nitride fine particles. Examples of organic fillers include organic fine particles such as silicone fine particles, methacrylate-butadiene-styrene fine particles, acryl-silicone fine particles, polyamide fine particles, and polyimide fine particles. These fine particles may have a uniform structure or may have a core-shell type structure. The maximum diameter of the filler is preferably less than the minimum diameter of the conductive particles 4 . The content of the filler may be, for example, 0.1% by volume or more and 50% by volume or less based on the total volume of the first curable composition.

The first curable composition may contain other additives such as softeners, accelerators, antidegradants, colorants, flame retardants, thixotropic agents, and the like. The content of these additives may be, for example, 0.1 to 10% by mass based on the total mass of the first curable composition. These additives may be contained in the first adhesive layer 2 .

The first curable composition may contain a thermosetting resin instead of or in addition to the components (A) and (B). A thermosetting resin is a resin that is cured by heat and has at least one or more thermosetting groups. A thermosetting resin is, for example, a compound that crosslinks by reacting with a curing agent by heat. As the thermosetting resin, one type of compound may be used alone, or a plurality of types of compounds may be used in combination.

The thermosetting group is, for example, an epoxy group, an oxetane group, an isocyanate group, etc., from the viewpoint of easily obtaining the desired melt viscosity, and from the viewpoint of further improving the effect of reducing the connection resistance and improving the connection reliability. good.

Specific examples of thermosetting resins include bisphenol-type epoxy resins, which are reaction products of epichlorohydrin and bisphenol A, F, AD, etc.; Epoxy resins such as various epoxy compounds having two or more glycidyl groups in one molecule such as novolac resins, naphthalene-based epoxy resins having a skeleton containing a naphthalene ring, glycidyl amines, glycidyl ethers, and the like.

When using a thermosetting resin instead of the components (A) and (B), the content of the thermosetting resin in the first curable composition is, for example, the total mass of the first curable composition. As a standard, it may be 20% by mass or more and may be 80% by mass or less. When using a thermosetting resin in addition to the components (A) and (B), the content of the thermosetting resin in the first curable composition is, for example, the total mass of the first curable composition As a standard, it may be 30% by mass or more and may be 70% by mass or less.

When the first curable composition contains a thermosetting resin, the first curable composition may contain the curing agent for the thermosetting resin described above. Curing agents for thermosetting resins include, for example, thermal radical generators, thermal cation generators, and thermal anion generators. The content of the curing agent may be, for example, 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the thermosetting resin.

The first adhesive layer 2 may contain components derived from the first curable composition, such as unreacted components (A) and (B). When the adhesive film 1 of the present embodiment is housed in a conventional housing member and stored and transported, the unreacted component (B) remains in the first adhesive layer 2, which may cause problems during storage and transport. In the middle, part of the second curable composition in the second adhesive layer 3 is cured, and peeling easily occurs between the circuit member and the circuit connection part in a high-temperature and high-humidity environment. It is presumed that problems such as a reduction in the effect of reducing the connection resistance of the film 1 occur. Therefore, from the viewpoint of suppressing the occurrence of the above problems, the content of the component (B) in the first adhesive layer 2 may be 15% by mass or less based on the total mass of the first adhesive layer. , 10% by mass or less, and may be 5% by mass or less. The content of component (B) in the first adhesive layer 2 may be 0.1% by mass or more based on the total mass of the first adhesive layer. When the first adhesive layer 2 contains a photopolymerization initiator as the component (B), the occurrence of the above problems can be suppressed by housing the adhesive film 1 in a housing member, which will be described later.

The melt viscosity X of the first adhesive layer 2 at the temperature Ty at which the second adhesive layer 3 exhibits the lowest melt viscosity Y may be 1000 Pa s or more, and may be 10000 Pa from the viewpoint of making peeling less likely to occur. ·s or more, and may be 50000 Pa·s or more. The melt viscosity X may be 10000000 Pa·s or less, 1000000 Pa·s or less, or 500000 Pa·s or less from the viewpoint of excellent wettability to the substrate. The melt viscosity X can be adjusted by changing the composition of the first curable composition, changing the curing conditions of the first curable composition, or the like.

The thickness d1 of the first adhesive layer 2 is 0.2 times or more the average particle diameter of the conductive particles 4 from the viewpoint that the conductive particles 4 are easily captured between the electrodes and the connection resistance can be further reduced. Well, it may be 0.3 times or more. The thickness d1 of the first adhesive layer 2 is such that when the conductive particles are sandwiched between opposing electrodes during thermocompression bonding, the conductive particles are more likely to be crushed, and the connection resistance can be further reduced. may be 0.8 times or less, and may be 0.7 times or less of the average particle size of From these viewpoints, the thickness d1 of the first adhesive layer 2 may be 0.2 to 0.8 times the average particle diameter of the conductive particles 4, and 0.3 to 0.7 times. good. 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 FIG. 4 may protrude from the first adhesive layer 2 toward the second adhesive layer 3 side. In this case, a boundary S between the first adhesive layer 2 and the second adhesive layer 3 is positioned at the spaced portion between the adjacent conductive particles 4,4. The conductive particles 4 are not exposed on the surface 2a of the first adhesive layer 2 opposite to the second adhesive layer 3 side, and the opposite surface 2a may be a flat surface.

The thickness d1 of the first adhesive layer 2 may be appropriately set according to the height of the electrodes of the circuit member to be adhered. The thickness d1 of the first adhesive layer 2 may be, for example, 0.5 μm or more and 20 μm or less. In addition, when a part of the conductive particles 4 is exposed from the surface of the first adhesive layer 2 (for example, protruding to the second adhesive layer 3 side), the second adhesive layer 2 The distance from the surface 2a on the opposite side of the adhesive layer 3 to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 located in the spaced part between the adjacent conductive particles 4, 4 ( 1) is the thickness of the first adhesive layer 2, and the exposed portion of the conductive particles 4 is not included in the thickness of the first adhesive layer 2. As shown in FIG. The length of the exposed portion of the conductive particles 4 may be, for example, 0.1 μm or more and 20 μm or less.

(Second adhesive layer)
The second adhesive layer 3 is made of, for example, a second curable composition. The second curable composition contains, for example, (a) a polymerizable compound (hereinafter also referred to as component (a)) and (b) a polymerization initiator (hereinafter also referred to as component (b)). The second curable composition may be a thermosetting composition containing a thermal polymerization initiator as component (b), and a photocurable composition containing a photopolymerization initiator as component (b). It may be a mixture of a thermosetting composition and a photocurable composition. The second curable composition that constitutes the second adhesive layer 3 is an uncured curable composition that can flow during circuit connection, for example, an uncured curable composition.

[(a) component: polymerizable compound]
The component (a) is, for example, a compound that polymerizes with radicals, cations, or anions generated by a polymerization initiator (photopolymerization initiator or thermal polymerization initiator) upon irradiation with light (eg, ultraviolet light) or heating. As the component (a), the compounds exemplified as the component (A) can be used. Component (a) reacts with radicals from the viewpoints of easy connection at low temperature and short time, easy to obtain desired melt viscosity, further improvement of connection resistance reduction effect, and excellent connection reliability. A radically polymerizable compound having a radically polymerizable group is preferred. Examples of preferred radically polymerizable compounds and preferred combinations of radically polymerizable compounds in component (a) are the same as for component (A). When the component (a) is a radically polymerizable compound and the component (B) in the first adhesive layer is a photoradical polymerization initiator, the adhesive film is housed in a housing member to be described later to achieve adhesion. Curing of the second curable composition during storage or transportation of the agent film tends to be significantly suppressed.

Component (a) may be a monomer, oligomer or polymer. As the component (a), one type of compound may be used alone, or a plurality of types of compounds may be used in combination. The component (a) may be the same as or different from the component (A).

The content of component (a) is 10% by mass based on the total mass of the second curable composition, from the viewpoint of easily obtaining the crosslink density necessary for reducing connection resistance and improving connection reliability. or more, may be 20% by mass or more, or may be 30% by mass or more. The content of the component (a) may be 90% by mass or less based on the total mass of the second curable composition, from the viewpoint of suppressing cure shrinkage during polymerization and obtaining good reliability. % by mass or less, and may be 70% by mass or less.

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

The content of the component (b) is 0.1% by mass or more, based on the total mass of the second curable composition, from the viewpoint of facilitating connection at low temperatures in a short time and from the viewpoint of better connection reliability. may be 0.5% by mass or more, and may be 1% by mass or more. 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 second curable composition, from the viewpoint of pot life. can be

[Other ingredients]
The second curable composition may further contain components other than components (a) and (b). Other components include, for example, thermoplastic resins, coupling agents, fillers, softeners, accelerators, antidegradants, colorants, flame retardants, thixotropic agents, and the like. Details of other components are the same as those of the other components in the first adhesive layer 2 .

The second curable composition may contain a thermosetting resin instead of the components (a) and (b) or in addition to the components (a) and (b). When the second curable composition contains a thermosetting resin, the second curable composition may contain a curing agent used to cure the thermosetting resin. As the thermosetting resin and curing agent, the same thermosetting resin and curing agent as those exemplified as other components in the first curable composition can be used. When a thermosetting resin is used instead of the components (a) and (b), the content of the thermosetting resin in the second curable composition is, for example, the total mass of the second curable composition. As a standard, it may be 20% by mass or more and may be 80% by mass or less. When using a thermosetting resin in addition to the components (a) and (b), the content of the thermosetting resin in the second curable composition is, for example, the total mass of the second curable composition As a standard, it may be 20% by mass or more and may be 80% by mass or less. The content of the curing agent may be the same as the range described as the content of the curing agent in the first curable composition.

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

The minimum melt viscosity Y of the second adhesive layer 3 may be 50 Pa s or more, 100 Pa s or more, or 300 Pa s or more from the viewpoint of obtaining excellent blocking resistance. . The minimum melt viscosity Y may be 100000 Pa s or less, 10000 Pa s or less, or 5000 Pa s or less from the viewpoint of obtaining excellent inter-electrode filling properties (resin filling properties). . The minimum melt viscosity Y can be adjusted by changing the composition of the second curable composition.

The thickness d2 of the second adhesive layer 3 may be appropriately set according to the height of the electrodes of the circuit member to be adhered. The thickness d2 of the second adhesive layer 3 may be 5 μm or more from the viewpoint that the space between the electrodes can be sufficiently filled and the electrodes can be sealed, and better reliability can be obtained. It may be 200 μm or less. In addition, when a part of the conductive particles 4 is exposed from the surface of the first adhesive layer 2 (for example, protruding to the second adhesive layer 3 side), the first The distance from the surface 3a on the opposite side of the adhesive layer 2 to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 located in the spaced part between the adjacent conductive particles 4, 4 ( The distance indicated by d2 in FIG. 1) is the thickness of the second adhesive layer 3 .

Ratio of thickness d1 of first adhesive layer 2 to thickness d2 of second adhesive layer 3 (thickness d1 of first adhesive layer 2/thickness d2 of second adhesive layer 3) may be 1 or more and may be 1000 or less from the viewpoint that the space between the electrodes can be sufficiently filled to seal the electrodes and better reliability can be obtained.

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

Although the circuit connection adhesive film of the present embodiment has been described above, the present invention is not limited to the above embodiment.

For example, the circuit-connecting adhesive film may be composed of two layers, a first adhesive layer and a second adhesive layer, except for the first adhesive layer and the second adhesive layer. It may be composed of three or more layers, including a layer of (for example, a third adhesive layer). The third adhesive layer may be a layer having a composition similar to that described above for the first adhesive layer or the second adhesive layer, wherein the first adhesive layer or the second adhesive layer It may be a layer having physical properties similar to the physical properties (e.g., melt viscosity) described above for, and may be a layer having a thickness similar to the thickness described above for the first adhesive layer or the second adhesive layer. . The circuit-connecting adhesive film may, for example, further comprise a third adhesive layer on the side of the first adhesive layer opposite the second adhesive layer. That is, the circuit-connecting adhesive film is formed by laminating, for example, a second adhesive layer, a first adhesive layer and a third adhesive layer in this order. In this case, the third adhesive layer consists, for example, of a second curable composition (for example a thermosetting composition) like the second adhesive layer.

Further, the circuit-connecting adhesive film of the above embodiment is an anisotropically conductive adhesive film having anisotropic conductivity, but the circuit-connecting adhesive film does not have anisotropic conductivity. It may be an adhesive film.

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

In the first preparation step, the first adhesive layer 2 is prepared, for example, by forming the first adhesive layer 2 on a substrate to obtain a first adhesive film. Specifically, first, components (A), (B), (C), and other components added as necessary are added to an organic solvent, and dissolved by stirring, mixing, kneading, or the like. Or dispersed to prepare a varnish composition. After that, the varnish composition is applied to the base material that has been subjected to the release treatment using a knife coater, roll coater, applicator, comma coater, die coater, etc., and then the organic solvent is volatilized by heating, and the to form a layer of the first curable composition. Subsequently, the layer composed of the first curable composition is irradiated with light or heated to cure the first curable composition and form the first adhesive layer 2 on the substrate. (hardening process). This gives the first adhesive film.

The organic solvent used for the preparation of the varnish composition is preferably a solvent capable of uniformly dissolving or dispersing each component, such as toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, and the like. is mentioned. These organic solvents can be used alone or in combination of two or more. Stirring, mixing and kneading during preparation of the varnish composition can be carried out using, for example, a stirrer, a kneader, a three-roll mill, a ball mill, a bead mill, or a homodisper.

The substrate is not particularly limited as long as it has heat resistance that can withstand the heating conditions when volatilizing the organic solvent when the first curable composition is cured by light. When the composition is cured by heating, there is no particular limitation as long as it has heat resistance that can withstand the heating conditions for volatilizing the organic solvent and the heating conditions for curing the first curable composition. . Examples of base materials include oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, and ethylene/acetic acid. Substrates (for example, films) made of vinyl copolymers, polyvinyl chloride, polyvinylidene chloride, synthetic rubbers, liquid crystal polymers, and the like can be used.

The heating conditions for volatilizing the organic solvent from the varnish composition applied to the substrate are preferably conditions under which the organic solvent is sufficiently volatilized. The heating conditions may be, for example, 40° C. or higher and 120° C. or lower for 0.1 minute or longer and 10 minutes or shorter.

It is preferable to use irradiation light (for example, ultraviolet light) having a wavelength within the range of 150 to 750 nm for light irradiation in the curing step. 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, or the like. The irradiation amount of light may be adjusted so that the melt viscosity ratio (X/Y) is 10 or more. The irradiation amount of light may be, for example, 100 mJ/cm ² or more, 200 mJ/cm ² or more, or 300 mJ/cm ² or more in terms of the integrated light amount of light having a wavelength of 365 nm. The irradiation amount of light may be, for example, 10000 mJ/cm ² or less, 5000 mJ/cm ² or less, or 3000 mJ/cm ² or less in terms of the integrated light amount of light having a wavelength of 365 nm. The melt viscosity X tends to increase as the light irradiation amount (integrated light amount of light) increases, and the melt viscosity ratio (X/Y) tends to increase.

The heating conditions in the curing step may be adjusted so that the melt viscosity ratio (X/Y) is 10 or more. The heating conditions may be, for example, 30° C. to 300° C. for 0.1 minute to 5000 minutes, or 50° C. to 150° C. for 0.1 minute to 3000 minutes. As the heating temperature is higher, the melt viscosity X tends to increase, and the melt viscosity ratio (X/Y) tends to increase. Also, the longer the heating time, the higher the melt viscosity X, which tends to increase the melt viscosity ratio (X/Y).

In the second preparation step, components (a) and (b) and other components added as necessary are used, and the curing step is not performed (light irradiation and heating are not performed). prepares the second adhesive layer 3 by forming the second adhesive layer 3 on the substrate to obtain a second adhesive film in the same manner as in the first preparation step.

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, and the first adhesive layer 3 may be laminated. A varnish composition obtained by using the components (a) and (b) and other components added as necessary is applied onto the adhesive layer 2, and the organic solvent is volatilized to form the first A second adhesive layer 3 may be laminated on the adhesive layer 2 of the above.

Examples of methods for bonding the first adhesive film and the second adhesive film include hot pressing, roll lamination, and vacuum lamination. Lamination may be performed under heating conditions of, for example, 0 to 80°C.

<Circuit connection structure and its manufacturing method>
A circuit-connecting structure using the circuit-connecting adhesive film 1 as a circuit-connecting material and a method for producing the same will be described below.

FIG. 2 is a schematic cross-sectional view showing a circuit connection structure according to one embodiment. As shown in FIG. 2, the circuit connection structure 10 includes a first circuit board 11 and a first circuit member 13 having a first electrode 12 formed on a main surface 11a of the first circuit board 11. , a second circuit member 16 having a second circuit board 14 and a second electrode 15 formed on a main surface 14a of the second circuit board 14, and a first circuit member 13 and a second circuit member 16 and a circuit connection portion 17 that electrically connects the first electrode 12 and the second electrode 15 to each other.

The first circuit member 13 and the second circuit member 16 may be the same or different. The first circuit member 13 and the second circuit member 16 may be a glass substrate or plastic substrate on which electrodes are formed, a printed wiring board, a ceramic wiring board, a flexible wiring board, a semiconductor silicon IC chip, or the like. The first circuit board 11 and the second circuit board 14 may be made of an inorganic material such as semiconductor, glass, or ceramic, an organic material such as polyimide or polycarbonate, a composite material such as glass/epoxy, or the like. First electrode 12 and second electrode 15 are made of gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, titanium, indium tin oxide (ITO), indium zinc oxide. (IZO), indium gallium zinc oxide (IGZO), or the like. 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 is formed of the adhesive film 1 described above. The circuit connection portion 17 is made of, for example, a cured product of the adhesive film 1 . The circuit connection portion 17 is positioned, for example, on the side of the first circuit member 13 in the direction in which the first circuit member 13 and the second circuit member 16 face each other (hereinafter referred to as "opposing direction"). Positioned on the second circuit member 16 side in the opposite direction to the first region 18 made of the cured product of the components such as the (A) component and the (B) component other than the conductive particles 4 of the curable composition ( Interposed between the second region 19 made of the cured product of the above-described second curable composition containing components a), (b), etc., and at least the first electrode 12 and the second electrode 15 and conductive particles 4 electrically connecting the first electrode 12 and the second electrode 15 to each other. The circuit connection part does not have to have two regions such as the first region 18 and the second region 19, for example, the components other than the conductive particles 4 of the first curable composition described above. It may consist of a cured product in which the cured product and the cured product of the second curable composition are mixed.

3A to 3C are schematic cross-sectional views showing a method for manufacturing the circuit connection structure 10. FIG. As shown in FIG. 3, the method for manufacturing the circuit connection structure 10 includes, for example, a first circuit member 13 having a first electrode 12 and a second circuit member 16 having a second electrode 15. Then, the above-described adhesive film 1 is interposed, and the first circuit member 13 and the second circuit member 16 are thermally compressed to electrically connect the first electrode 12 and the second electrode 15 to each other. Prepare.

Specifically, first, as shown in FIG. A member 13, a second circuit board 14, and a second circuit member 16 having a second electrode 15 formed on the main surface 14a of the second circuit board 14 are prepared.

Next, the first circuit member 13 and the second circuit member 16 are arranged so that the first electrode 12 and the second electrode 15 face each other, and the first circuit member 13 and the second circuit member 16 are arranged. The adhesive film 1 is arranged between the circuit member 16 and the circuit member 16 . For example, as shown in FIG. 3A, the adhesive film 1 is laminated on the first circuit member 13 so that the first adhesive layer 2 side faces the mounting surface 11a of the first circuit member 13. do. Next, a first adhesive film 1 is laminated such that the first electrode 12 on the first circuit board 11 and the second electrode 15 on the second circuit board 14 face each other. A second circuit member 16 is arranged on the circuit member 13 . Further, for example, the adhesive film 1 may be laminated on the second circuit member 16 so that the first adhesive layer 2 side faces the mounting surface 14 a of the second circuit member 16 . In this case, the second adhesive film 1 is laminated such that the first electrodes 12 on the first circuit board 11 and the second electrodes 15 on the second circuit board 14 face each other. A first circuit member 13 is placed on the circuit member 16 .

Then, as shown in FIG. 3B, the first circuit member 13 and the second circuit member 16 are heated while the first circuit member 13, the adhesive film 1 and the second circuit member 16 are heated. By applying pressure in the thickness direction, the first circuit member 13 and the second circuit member 16 are thermocompression bonded to each other. At this time, the adhesive film 1 is heated to a temperature Ty at which the second adhesive layer 3 exhibits the lowest melt viscosity Y. In the present embodiment, since the melt viscosity ratio (X/Y) of the adhesive film 1 is 10 or more, during the thermocompression bonding, the second adhesive layer 3 can flow while the first adhesive layer 3 can flow. The agent layer 2 hardly flows. As a result, as indicated by arrows in FIG. 3(b), the second adhesive layer flows so as to fill the gap between the second electrodes 15, 15 and is cured by the heating. As a result, the first electrode 12 and the second electrode 15 are electrically connected to each other through the conductive particles 4, and the first circuit member 13 and the second circuit member 16 are adhered to each other. 2 is obtained. In the method for manufacturing the circuit connection structure 10 of the present embodiment, the conductive particles 4 are fixed in the first adhesive layer 2, and the first adhesive layer 2 hardly flows during the thermocompression bonding. , the connection resistance between the opposing electrodes 12 and 15 is reduced. Therefore, a circuit connection structure having excellent connection reliability can be obtained. In addition, when the second curable composition contains a photocurable composition, instead of thermocompression bonding by heating, the first circuit is formed by performing pressurization and light irradiation, or pressurization and heating and light irradiation. Member 13 and second circuit member 16 may be joined together.

<Adhesive film storage set>
FIG. 4 is a perspective view of an adhesive film containing set according to one embodiment. As shown in FIG. 4, the adhesive film containing set 20 includes a circuit-connecting adhesive film 1, a reel 21 around which the adhesive film 1 is wound, and a containing member 22 containing the adhesive film 1 and the reel 21. And prepare.

As shown in FIG. 4, the adhesive film 1 is tape-shaped, for example. The tape-shaped adhesive film 1 is produced, for example, by cutting a sheet-shaped raw material into a long length having a width according to the application. A substrate may be provided on one surface of the adhesive film 1 . As the base material, a base material such as the PET film described above can be used.

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

The first side plate 24 is, for example, a disk made of plastic, and an opening having a circular cross section is provided in the central portion of the first side plate 24 .

A winding core 23 of the first side plate 24 is a portion around which the adhesive film 1 is wound. The winding core 23 is made of plastic, for example, and has an annular shape with the same thickness as the width of the adhesive film 1 . The winding core 23 is fixed to the inner surface of the first side plate 24 so as to surround the opening of the first side plate 24 . A central portion of the reel 21 is provided with a shaft hole 26 into which a rotating shaft of a winding device or a feeding device (not shown) is inserted. When the rotating shaft of the winding device or the feeding device is inserted into the shaft hole 26 and the rotating shaft is driven, the reel 21 rotates without idling. A desiccant storage container containing a desiccant may be fitted in the shaft hole 26 .

Like the first side plate 24, the second side plate 25 is a circular plate made of plastic, for example. is provided with an opening.

The containing member 22 has, for example, a bag shape and contains the adhesive film 1 and the reel 21 . The containing member 22 has an insertion opening 27 for containing (inserting) the adhesive film 1 and the reel 21 inside the containing member 22 .

The containing member 22 has a viewing portion 28 that allows the inside of the containing member 22 to be visually recognized from the outside. The housing member 22 shown in FIG. 4 is configured so that the entire housing member 22 serves as the visual recognition portion 28 .

The visual recognition portion 28 has transparency to visible light. For example, when the light transmittance in the visible portion 28 is measured in the wavelength range of 450 to 750 nm, the average value of the light transmittance is 30% or more between the wavelengths of 450 to 750 nm, and the wavelength width is 50 nm. There is at least one region. The light transmittance of the visible part 28 is obtained by cutting a sample of the visible part 28 to a predetermined size and measuring the light transmittance of the sample with an ultraviolet-visible spectrophotometer. Since the housing member 22 has such a visual recognition part 28, various kinds of information such as the product name, lot number, expiration date, etc. attached to the reel 21 inside the housing member 22 can be confirmed even from the outside of the housing member 22. be able to. This can be expected to prevent mixing of different products and to improve the efficiency of sorting work.

The transmittance of light with a wavelength of 365 nm in the visual recognition portion 28 is 10% or less. Since the transmittance of light with a wavelength of 365 nm in the visible portion 28 is 10% or less, when a photopolymerization initiator is used as the component (B), light entering from the outside to the inside of the housing member 22 and the first Curing of the second curable composition caused by the photopolymerization initiator remaining in the adhesive layer 2 can be suppressed. As a result, it is possible to suppress the occurrence of problems such as the tendency of the circuit member to separate from the circuit connecting portion in a high-temperature and high-humidity environment, and the decrease in the effect of reducing the connection resistance of the adhesive film. From the viewpoint of further suppressing the generation of active species (for example, radicals) from the photopolymerization initiator, the transmittance of light with a wavelength of 365 nm in the visible portion 28 is preferably 10% or less, more preferably 5% or less, and even more preferably. is 1% or less, particularly preferably 0.1% or less.

From the same point of view, the maximum value of light transmittance in the wavelength region capable of generating radicals, cations or anions from the photopolymerization initiator (component (B)) in the visible portion 28 is preferably It is 10% or less, more preferably 5% or less, still more preferably 1% or less, and particularly preferably 0.1% or less. Specifically, the maximum transmittance of light at a wavelength of 254 to 405 nm in the visible portion 28 is preferably 10% or less, more preferably 5% or less, even more preferably 1% or less, and particularly preferably 0.1%. It is below.

The visual recognition portion 28 (accommodating member 22) is formed of a sheet having a thickness of 10 to 5000 μm, for example. The sheet is made of a material having a transmittance of 10% or less for light with a wavelength of 365 nm in the visible portion 28 . Such materials may consist of one type of component, or may consist of multiple types of components. Examples of such materials include low-density polyethylene, linear low-density polyethylene, polycarbonate, polyester, acrylic resin, polyamide, and glass. These materials may contain UV absorbers. The visual recognition part 28 may have a laminated structure formed by laminating a plurality of layers with different light transmittance. In this case, each layer constituting the visual recognition portion 28 may be made of the materials described above.

The insertion opening 27 may be closed by, for example, a sealing machine or the like to prevent air from entering from the outside during accommodation. In this case, it is preferable to remove the air inside the housing member 22 by suction before closing the insertion port 27 . It can be expected that the humidity in the housing member 22 will be reduced from the initial stage of housing, and the intrusion of air from the outside will be prevented. In addition, since the inner surface of the housing member 22 and the reel 21 are in close contact with each other, the inner surface of the housing member 22 and the surface of the reel 21 rub against each other due to vibration during transportation, and foreign matter is generated. , 25 can be prevented from being damaged.

In the above embodiment, the housing member is configured so that the entire housing member serves as the visual recognition portion. good too. For example, the housing member may have a rectangular viewing portion approximately in the center of the side surface of the housing member. In this case, the portion of the housing member other than the viewing portion may be black, for example, so as not to transmit ultraviolet light and visible light.

Further, in the above embodiment, the shape of the containing member is bag-like, but the containing member may be box-shaped, for example. The containing member preferably has a notch for opening. In this case, the unsealing operation at the time of use is facilitated.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the examples.

<Synthesis of polyurethane acrylate (UA1)>
Poly(1,6-hexanediol carbonate) (trade name: Duranol T5652, manufactured by Asahi Kasei Chemicals Co., Ltd.) was added to a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser with a calcium chloride drying tube, and a nitrogen gas introduction tube. , number average molecular weight 1000) 2500 parts by mass (2.50 mol) and isophorone diisocyanate (manufactured by Sigma-Aldrich) 666 parts by mass (3.00 mol) were uniformly added dropwise over 3 hours. Then, after sufficiently introducing nitrogen gas into the reaction vessel, the inside of the reaction vessel was heated to 70 to 75° C. for 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 vessel. After that, 238 parts by mass (2.05 mol) of 2-hydroxyethyl acrylate (manufactured by Sigma-Aldrich) was added and reacted at 70° C. for 6 hours in an air atmosphere. This gave a polyurethane acrylate (UA1). The weight average molecular weight of polyurethane acrylate (UA1) was 15,000. The weight average molecular weight was measured using a standard polystyrene calibration curve from gel permeation chromatography (GPC) under the following conditions.
(Measurement condition)
Device: 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: 120mg/3mL
Solvent: Tetrahydrofuran Injection volume: 60 μL
Pressure: 2.94×10 ⁶ Pa (30 kgf/cm ² )
Flow rate: 1.00mL/min

<Production of conductive particles>
A layer of nickel was formed on the surface of the polystyrene particles so that the layer thickness was 0.2 μm. Thus, 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 of varnish (varnish composition) of first curable composition>
The components shown below were mixed in the compounding amounts (parts by mass) shown in Table 1 to prepare a varnish of the first curable composition 1 and a varnish of the first curable composition 2. The content (% by volume) of the conductive particles and the content (% by volume) of the filler described in Table 1 are based on the total volume of the first curable composition.
(Polymerizable compound)
A1: Dicyclopentadiene-type diacrylate (trade name: Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd. )
A2: Polyurethane acrylate (UA1) synthesized as described above
A3: 2-methacryloyloxyethyl acid phosphate (trade name: Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.)
(Polymerization initiator)
B1: 1,2-octanedione, 1-[4-(phenylthio)phenyl-,2-(O-benzoyloxime)] (trade name: Irgacure (registered trademark) OXE01, manufactured by BASF)
B2: Benzoyl peroxide (trade name: Nyper BMT-K40, manufactured by NOF Corporation)
(Conductive particles)
C1: Conductive particles (thermoplastic resin) produced as described above
D1: Bisphenol A type phenoxy resin (trade name: PKHC, manufactured by Union Carbide Co., Ltd.)
(coupling agent)
E1: 3-methacryloxypropyltrimethoxysilane (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.)
(filler)
F1: Silica fine particles (trade name: R104, manufactured by Nippon Aerosil Co., Ltd., average particle size (primary particle size): 12 nm, specific gravity: 2)
(solvent)
G1: methyl ethyl ketone

<Preparation of varnish of second curable composition (varnish composition)>
Polymerizable compounds a1 to a3, polymerization initiator b1, thermoplastic resin d1, coupling agent e1, filler f1 and solvent g1 as polymerizable compounds A1 to A3 in the first curable composition, polymerization initiator B2, Using the same thermoplastic resin D1, coupling agent E1, filler F1, and solvent G1, these components are mixed in the amounts (parts by mass) shown in Table 2, and the varnish of the second curable composition 1 was prepared. In addition, the content (% by volume) of the filler described in Table 2 is the content based on the total volume of the second curable composition.

(Example 1)
[Preparation of first adhesive film]
A varnish of the first curable composition 1 was applied onto a PET film having a thickness of 50 μm using a coating device. Then, hot air drying was performed at 70° C. for 3 minutes to form a layer of the first curable composition 1 having a thickness (thickness after drying) of 2 μm on the PET film. Next, the layer composed of the first curable composition 1 was irradiated with light using a metal halide lamp so that the integrated light amount was 300 mJ/cm ² to polymerize the polymerizable compound. Thereby, the first curable composition 1 was cured to form a first adhesive layer. Through the above operations, a first adhesive film having a first adhesive layer with a thickness of 2 μm on a PET film was obtained. The conductive particle density at this time was about 7000 pcs/mm ² . The thickness of the first adhesive layer was measured using a laser microscope OLS4100 manufactured by Olympus Corporation.

[Preparation of second adhesive film]
A varnish of the second curable composition 1 was applied onto a PET film having a thickness of 50 μm using a coating device. Then, hot air drying was performed at 70° C. for 3 minutes to form a second adhesive layer (a layer made of the second curable composition 1) having a thickness of 10 μm on the PET film. A second adhesive film having a second adhesive layer on a PET film was obtained by the above operation.

[Measurement of melt viscosity]
The melt viscosity of the first adhesive layer and the lowest melt viscosity of the second adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity were measured by the following method. Specifically, first, the first adhesive film and the second adhesive film were each laminated with a roll laminator while being heated at 40° C. so as to have a thickness of 200 μm. After that, it was cut to 0.8 cmφ to obtain a test piece. Next, the obtained test piece was subjected to melt viscosity measurement using a melt viscosity measuring device (trade name: ARES-G2, manufactured by TA Instruments). The measurement conditions were as follows: measurement temperature: 0 to 200°C, heating rate: 10°C/min, frequency: 10Hz, strain: 0.5%.

The temperature (temperature Ty) at which the second adhesive layer exhibited the lowest melt viscosity was 103°C. The melt viscosity (melt viscosity X) of the first adhesive layer at temperature Ty was 6×10 ⁴ Pa·s. The lowest melt viscosity (lowest melt viscosity Y) of the second adhesive layer was 1×10 ³ Pa·s. From these results, the melt viscosity ratio (X/Y) was 60. In the above measurements, the thickness of the first adhesive film and the second adhesive film was set to 200 μm, but the thickness of the adhesive film is not particularly limited, and may be, for example, 100 to 1000 μm. .

[Preparation of adhesive film for circuit connection]
The first adhesive film and the second adhesive film were laminated with a roll laminator while being heated at 40° C. together with the PET film as the substrate. As a result, a substrate-attached circuit-connecting adhesive film was produced, which included a two-layer circuit-connecting adhesive film in which the first adhesive layer and the second adhesive layer were laminated.

[Production of circuit connection structure]
A thin film electrode comprising a COF (manufactured by FLEXSEED) with a pitch of 25 μm and a thin film electrode (height: 1200 Å) made of amorphous indium tin oxide (ITO) on a glass substrate through the prepared adhesive film for circuit connection. A glass substrate (manufactured by Geomatec) is heated and pressed at 170 ° C. and 6 MPa for 4 seconds using a thermocompression bonding device (heating method: constant heat type, manufactured by Taiyo Kikai Seisakusho Co., Ltd.). A circuit connection structure (connection structure) having a circuit connection portion formed by a circuit connection adhesive film was prepared by connecting over 1 mm. At the time of connection, the circuit-connecting adhesive film was arranged on the glass substrate so that the surface of the circuit-connecting adhesive film on the first adhesive layer side faced the glass substrate.

[Peeling evaluation]
The connection appearance of the obtained circuit connection structure immediately after connection and the connection appearance after the high-temperature and high-humidity test were observed using an optical microscope to evaluate peeling. Specifically, from the side of the glass substrate with thin-film electrodes, the area where peeling occurred between the glass substrate and the circuit connecting portion (peeling area) was measured. The high-temperature and high-humidity test was performed by leaving it in a constant temperature and humidity chamber at 85° C. and 85% RH for 200 hours. Table 3 shows the results.

[Blocking resistance evaluation]
The prepared adhesive film for circuit connection with a substrate was slit to 0.6 mm to obtain a tape-shaped adhesive film with a substrate. A core with a width of 0.7 mm, an inner diameter of 40 mm, and an outer diameter of 65 mm, and an annular ring made of plastic with a thickness of 2 mm, an inner diameter of 40 mm, and an outer diameter of 125 mm, one at each end of the core (two in total). A side plate and a reel for adhesive tape were prepared, and the tape-shaped adhesive film with a base material was wound around the reel for adhesive tape with the surface on the adhesive film side facing inward. As described above, an adhesive reel was obtained by winding an adhesive film with a substrate having a length of 50 m and a width of 0.6 mm around a winding core.

The obtained adhesive reel was left in a constant temperature bath at 30° C. for 24 hours, and then it was confirmed whether or not the adhesive film could be pulled out without any problem. It was evaluated as A when it could be pulled out without problems, and as B when problems such as sticking to the base material (blocking) occurred when it was pulled out. Table 3 shows the results.

(Example 2)
An adhesive film for circuit connection and a circuit connection structure were performed in the same manner as in Example 1, except that light irradiation was performed so that the integrated light amount was 2000 mJ/cm ² when producing the first adhesive film. A body was prepared, and melt viscosity measurement, peeling evaluation, and blocking resistance evaluation were performed in the same manner as in Example 1. Table 3 shows the results.

(Example 3)
The use of the first curable composition 2 instead of the first curable composition 1, and the first curable composition instead of light irradiation during the production of the first adhesive film A circuit-connecting adhesive film and a circuit-connecting structure were prepared in the same manner as in Example 1, except that the layer composed of the substance 2 was cured by heating at 100 ° C. for 20 minutes, and the same as in Example 1. Then, melt viscosity measurement, peeling evaluation and blocking resistance evaluation were performed. Table 3 shows the results.

(Example 4)
The use of the first curable composition 2 instead of the first curable composition 1, and the first curable composition instead of light irradiation during the production of the first adhesive film A circuit-connecting adhesive film and a circuit-connecting structure were prepared in the same manner as in Example 1, except that the layer composed of the substance 2 was cured by heating at 100 ° C. for 180 minutes, and the same as in Example 1. Then, melt viscosity measurement, peeling evaluation and blocking resistance evaluation were performed. Table 3 shows the results.

(Example 5)
The use of the first curable composition 2 instead of the first curable composition 1, and the first curable composition instead of light irradiation during the production of the first adhesive film A circuit-connecting adhesive film and a circuit-connecting structure were prepared in the same manner as in Example 1, except that the layer composed of the substance 2 was cured by heating at 100 ° C. for 5 minutes, and the same as in Example 1. Then, melt viscosity measurement, peeling evaluation and blocking resistance evaluation were performed. Table 3 shows the results.

(Comparative example 1)
The first curable composition 2 was used instead of the first curable composition 1, and light irradiation was not performed during the preparation of the first adhesive film (first curable composition A circuit-connecting adhesive film and a circuit-connecting structure were prepared in the same manner as in Example 1, except that the layer composed of composition 2 was not cured, and the melt viscosity was measured in the same manner as in Example 1. , peeling evaluation and blocking resistance evaluation were performed. Table 4 shows the results.

(Comparative example 2)
The circuit-connecting adhesive film and the circuit-connecting structure were performed in the same manner as in Example 1, except that light irradiation was performed so that the integrated light amount was 50 mJ/cm ² when the first adhesive film was produced. A body was prepared, and melt viscosity measurement, peeling evaluation, and blocking resistance evaluation were performed in the same manner as in Example 1. Table 4 shows the results.

(Comparative Example 3)
The use of the first curable composition 2 instead of the first curable composition 1, and the first curable composition instead of light irradiation during the production of the first adhesive film A circuit-connecting adhesive film and a circuit-connecting structure were prepared in the same manner as in Example 1, except that the layer composed of the product 2 was cured by heating at 60 ° C. for 30 minutes, and the same as in Example 1. Then, melt viscosity measurement, peeling evaluation and blocking resistance evaluation were performed. Table 4 shows the results.

DESCRIPTION OF SYMBOLS 1... Adhesive film for circuit connection, 2... 1st adhesive layer, 3... 2nd adhesive layer, 4... Conductive particle, 10... Circuit connection structure, 12... Circuit electrode (first electrode), DESCRIPTION OF SYMBOLS 13... 1st circuit member, 15... Bump electrode (2nd electrode), 16... 2nd circuit member, 20... Adhesive film accommodation set, 22... Accommodating member, 28... Visible part.

Claims (13)

A first adhesive layer containing conductive particles, and a second adhesive layer laminated on the first adhesive layer,
The first adhesive layer is made of a cured product of the first curable composition,
The first curable composition contains a radically polymerizable compound having a radically polymerizable group and a photopolymerization initiator having an oxime ester structure , and at least one of the radically polymerizable compounds is a (poly)urethane (meth) ) is an acrylate compound,
For circuit connection, wherein the ratio of the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity to the lowest melt viscosity of the second adhesive layer is 10 or more. adhesive film. A first adhesive layer containing conductive particles, and a second adhesive layer laminated on the first adhesive layer,
The first adhesive layer is made of a cured product of the first curable composition,
The first curable composition contains a radically polymerizable compound having a radically polymerizable group, at least one of the radically polymerizable compounds is a (poly)urethane (meth)acrylate compound,
The ratio of the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity to the lowest melt viscosity of the second adhesive layer is 10 or more,
The adhesive film for circuit connection, wherein the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity is 10000 Pa·s or more. 2. The adhesive film for circuit connection according to claim 1 , wherein the melt viscosity of said first adhesive layer at the temperature at which said second adhesive layer exhibits said lowest melt viscosity is 10000 Pa.s or more. the second adhesive layer comprises a second curable composition;
The adhesive film for circuit connection according to any one of claims 1 to 3, wherein the second curable composition contains a radically polymerizable compound having a radically polymerizable group. The adhesive film for circuit connection according to any one of claims 1 to 4, wherein the thickness of the first adhesive layer is 0.2 to 0.8 times the average particle size of the conductive particles. . A preparation step of preparing a first adhesive layer;
A lamination step of laminating a second adhesive layer made of a second curable composition on the first adhesive layer,
In the preparation step, the layer made of the first curable composition containing conductive particles is irradiated with light or heated to cure the first curable composition, and the first adhesive layer is formed. including a curing step to obtain
The first adhesive layer is made of a cured product of the first curable composition,
The first curable composition contains a radically polymerizable compound having a radically polymerizable group and a photopolymerization initiator having an oxime ester structure , and at least one of the radically polymerizable compounds is a (poly)urethane (meth) ) is an acrylate compound,
In the curing step, the ratio of the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity to the lowest melt viscosity of the second adhesive layer is 10 or more. A method for producing an adhesive film for circuit connection, wherein the first curable composition is cured such that A preparation step of preparing a first adhesive layer;
A lamination step of laminating a second adhesive layer made of a second curable composition on the first adhesive layer,
In the preparation step, the layer made of the first curable composition containing conductive particles is irradiated with light or heated to cure the first curable composition, and the first adhesive layer is formed. including a curing step to obtain
The first adhesive layer is made of a cured product of the first curable composition,
The first curable composition contains a radically polymerizable compound having a radically polymerizable group, at least one of the radically polymerizable compounds is a (poly)urethane (meth)acrylate compound,
In the curing step, the ratio of the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity to the lowest melt viscosity of the second adhesive layer is 10 or more. The first curable composition is added so that the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity is 10000 Pa s or more. A method for producing a cured circuit-connecting adhesive film. 7. The method for producing a circuit-connecting adhesive film according to claim 6 , wherein the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity is 10000 Pa·s or more. . The method for producing an adhesive film for circuit connection according to any one of claims 6 to 8, wherein the second curable composition contains a radically polymerizable compound having a radically polymerizable group. The adhesive film for circuit connection according to any one of claims 6 to 9, wherein the thickness of the first adhesive layer is 0.2 to 0.8 times the average particle diameter of the conductive particles. manufacturing method. Between the first circuit member having the first electrode and the second circuit member having the second electrode, the adhesive film for circuit connection according to any one of claims 1 to 5 is interposed. and thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other. . A circuit connection adhesive film according to any one of claims 1 to 5, and a containing member containing the adhesive film,
The housing member has a viewing portion that allows the inside of the housing member to be visually recognized from the outside,
The adhesive film accommodation set, wherein the visible portion has a transmittance of 10% or less for light with a wavelength of 365 nm. An adhesive film for circuit connection and a housing member for housing the adhesive film,
The circuit connection adhesive film comprises a first adhesive layer containing conductive particles and a second adhesive layer laminated on the first adhesive layer,
The first adhesive layer is made of a cured product of the first curable composition,
The first curable composition contains a radically polymerizable compound having a radically polymerizable group, at least one of the radically polymerizable compounds is a (poly)urethane (meth)acrylate compound,
The ratio of the melt viscosity of the first adhesive layer at the temperature at which the second adhesive layer exhibits the lowest melt viscosity to the lowest melt viscosity of the second adhesive layer is 10 or more,
The housing member has a viewing portion that allows the inside of the housing member to be visually recognized from the outside,
The adhesive film accommodation set, wherein the visible portion has a transmittance of 10% or less for light with a wavelength of 365 nm.

Images