JPWO2019050011A1 - Adhesive film for circuit connection, manufacturing method thereof, manufacturing method of circuit connection structure, and adhesive film accommodating set - Google Patents

Abstract

A first adhesive layer (2) containing conductive particles (4) and a second adhesive layer (3) laminated on the first adhesive layer (2), the minimum of the second adhesive layer (3) The adhesive film 1 for circuit connection, wherein the ratio of the melt viscosity of the first adhesive layer 2 at the temperature at which the second adhesive layer 3 exhibits the minimum melt viscosity to the melt viscosity is 10 or more.

Description

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 accommodation set.

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

In the field of precision electronic equipment, in which an adhesive film for circuit connection having anisotropic conductivity is used, the circuit density is increasing, and the electrode width and the electrode interval are extremely narrow. Therefore, it is not always easy to efficiently capture the conductive particles on the microelectrode and obtain high connection reliability.

On the other hand, for example, Patent Document 1 proposes a method in which conductive particles are unevenly distributed on one side of the anisotropic conductive adhesive sheet and the conductive particles are separated from each other.

International Publication No. 2005/54388

By the way, when the circuit connection structure obtained by using the conventional adhesive film for circuit connection 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 connection reliability of the circuit connection structure.

Therefore, the present invention provides an adhesive film for circuit connection, a method for producing the same, and a method for producing the same, in which a circuit connecting structure can be obtained in which peeling between a circuit member and a circuit connecting portion is less likely to occur in a high temperature and high humidity environment. An object of the present invention is to provide a method of manufacturing a circuit connection structure using a film, and an adhesive film accommodation 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 minimum melt viscosity to the minimum 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 does not easily occur between the circuit member and the circuit connection portion in a high temperature and high humidity environment (for example, 85° C., 85% RH). .. In other words, according to this adhesive film for circuit connection, it is possible to improve the adhesion between the circuit member and the circuit connecting portion under a high temperature and high humidity environment. Furthermore, according to this adhesive film for circuit connection, it is possible to reduce the connection resistance of the electrodes facing each other in the circuit connection structure, and to achieve low connection even in a high temperature and high humidity environment (for example, 85° C., 85% RH). The 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 includes a preparing step of preparing a first adhesive layer, and a second step of forming a second curable composition on the first adhesive layer. Laminating step of laminating the adhesive layer of the first curable composition, wherein the preparing step comprises irradiating or heating the layer made of the first curable composition containing the conductive particles with the first curable composition. A curing step of curing an object to obtain a first adhesive layer, in which the first adhesive layer at a temperature at which the second adhesive layer exhibits the minimum melt viscosity with respect to the minimum melt viscosity of the second adhesive layer. The first curable composition is cured such that the melt viscosity ratio of the adhesive layer is 10 or more. According to this method, it is possible to obtain an adhesive film for circuit connection, which makes it possible to obtain a circuit connection structure in which peeling between the circuit member and the circuit connection portion hardly occurs in a high temperature and 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 be composed of the second curable composition, and the second curable composition may contain a radical polymerizable compound having a radical 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 connecting structure, wherein the above-mentioned circuit connecting adhesive is provided between a first circuit member having a first electrode and a second circuit member having a second electrode. A step of thermocompressing the first circuit member and the second circuit member with the agent film interposed therebetween to electrically connect the first electrode and the second electrode to each other is provided. According to this method, it is possible to obtain a circuit connecting structure in which separation between the circuit member and the circuit connecting portion is unlikely to occur in a high temperature and high humidity environment.

An adhesive film housing set according to one aspect of the present invention includes the above-mentioned adhesive film for circuit connection and a housing member that houses the adhesive film, and the housing member allows the inside of the housing member to be visually recognized from the outside. And a 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 the adhesive film for circuit connection is used is a room called a clean room in which the temperature, humidity, and cleanliness of the room are controlled at a certain level. When the adhesive film for circuit connection is shipped from the production site, it is directly exposed to the outside air, and the adhesive film for circuit connection is stored in a storage bag or other storage member to prevent deterioration of quality due to dust and moisture. To do. Normally, this container is 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 can be confirmed from outside the container. Section is provided.

However, when the above-mentioned adhesive film for circuit connection is used after being stored or transported by being housed in a conventional housing member, peeling between the circuit member and the circuit connecting portion is likely to occur in a high temperature and high humidity environment. However, it has been clarified by the study by the present inventors that a problem such as a decrease in the effect of reducing the connection resistance of the adhesive film may occur. When the present inventors further conducted a study based on such examination results, the first adhesive layer was composed of a cured product of a photocurable composition, and the second adhesive layer was composed of the photocurable composition. In the case of a curable composition containing a polymerizable compound capable of reacting with a photopolymerization initiator in the product, the second adhesive layer may be cured during storage and transportation of the adhesive film, and the above-mentioned problems may occur. It was revealed. Therefore, the present inventors further presume 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 examination, it is possible to suppress the curing of the second adhesive layer during storage or transportation by using the adhesive film storage set including the specific storage member, and to suppress the occurrence of the above-mentioned problems. I found that I could do it.

That is, according to the adhesive film accommodation set of one aspect of the present invention, in the case where 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, , It is possible to suppress the curing of the second adhesive layer during storage or transportation of the adhesive film, and to facilitate peeling between the circuit member and the circuit connecting portion in a high temperature and high humidity environment. It is possible to suppress the occurrence of defects such as a decrease in the connection resistance reduction effect of the agent film.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive film for circuit connection which can obtain the circuit connecting structure which peeling between a circuit member and a circuit connecting part does not easily generate|occur|produce under high temperature 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 accommodation set including the adhesive film.

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

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings in some cases. In the present specification, the upper limit value and the lower limit value, which are individually described, can be arbitrarily combined. Further, in the present specification, “(meth)acrylate” means at least one of acrylate and corresponding methacrylate. 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 of one embodiment. As shown in FIG. 1, an adhesive film 1 for circuit connection (hereinafter, also simply referred to as “adhesive film 1”) is laminated on a first adhesive layer 2 and on 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, the conductive particles 4 are dispersed in the first adhesive layer 2. Therefore, the adhesive film 1 is an anisotropic conductive adhesive film having anisotropic conductivity. The adhesive film 1 is 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. Used for thermocompression bonding 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 minimum melt viscosity Y to the minimum 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 connecting structure in which peeling between the circuit member and the circuit connecting portion hardly occurs in a high temperature and high humidity environment (for example, 85° C., 85% RH).

Furthermore, according to the adhesive film 1, it is possible to reduce the connection resistance of the electrodes facing each other of the circuit connection structure, and to maintain the low connection resistance even in a high temperature and high humidity environment (for example, 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 there are the following two contributions. The first point is that, in the present embodiment, since the melt viscosity ratio (X/Y) of the adhesive film 1 is 10 or more, the conductive particles 4 are fixed by the first adhesive layer 2 and the conductivity at the time of connection is improved. This is because the flow of the particles 4 is suppressed, and as a result, the efficiency of capturing the conductive particles 4 at the electrode is improved. The second point is that in the present embodiment, the ratio (X/Y) of the melt viscosity of the adhesive film 1 is 10 or more, so that the flow of the first adhesive layer 2 is the This is a contribution due to being largely suppressed as compared with the adhesive layer 3. For example, in the case of short-time pressure bonding such as 170° C. for 5 seconds, in the case of a normal adhesive (for example, an adhesive having a two-layer structure), the fluidization and curing of both layers of the two laminated adhesive layers proceed simultaneously. At this time, at the interface between the adhesive layer and the circuit member, the adhesive constituting the adhesive layer flows and the curing of the adhesive proceeds, so that distortion or internal stress is likely to occur. On the other hand, in the present embodiment, the flow and cure of the second adhesive layer 3 occur, but the flow and cure of the first adhesive layer 2 hardly occur. Therefore, distortion or internal stress is unlikely to occur between the circuit member and the first adhesive layer 2, and the adhesion between the circuit member and the circuit connecting portion in a high temperature and high humidity environment can be improved. It is estimated that the connection reliability can be improved.

Further, the adhesive film 1 is stored and used as an adhesive reel by slitting the adhesive film 1 with a base material formed on one surface of the base material in a narrow width and winding the slit on a core. There are cases where This adhesive reel is required to have good blocking resistance that the adhesive film 1 is not easily peeled off from the base material when the adhesive film with the base material is fed from the adhesive reel. However, in the conventional adhesive film, it may be difficult to obtain good blocking resistance when slitting in a narrow width of about 0.4 to 1.0 mm. On the other hand, in the adhesive film 1 of the present embodiment, since the melt viscosity ratio (X/Y) is 10 or more, sticking (blocking) between the first adhesive layer 2 and the base material is suppressed. Therefore, by providing the base material on the surface of the second adhesive layer 3 on the side opposite to the first adhesive layer 2, good blocking resistance can be achieved even when slitting in the narrow width as described above. Tends to be obtained. The blocking resistance can be evaluated, for example, by a test for confirming whether or not the adhesive reel can be pulled out without any problem after being left in a 30° C. environment 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 the adhesion to the circuit member. Is 100 or more. The melt viscosity ratio (X/Y) may be 10000 or less, 5000 or less, or 1000 or less from the viewpoint of wettability to a circuit member. From these viewpoints, the melt viscosity ratio (X/Y) may be 10 to 10000, 20 to 5000, 50 to 5000, or 100 to 1000. The melt viscosity X and the minimum melt viscosity Y can be determined by measuring the melt viscosity of the first adhesive layer 2 and the second adhesive layer 3 by the method described in the examples. Specifically, first, by measuring the melt viscosity of the second adhesive layer 3, the minimum melt viscosity Y of the second adhesive layer 3 (and the temperature Ty at which the second adhesive layer exhibits the minimum melt viscosity Y). Then, the melt viscosity X of the first adhesive layer 2 at the temperature Ty is calculated by measuring the melt viscosity of the first adhesive layer 2. The melt viscosity can 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 the photocurable composition and the thermosetting composition. The first curable composition is, for example, (A) a polymerizable compound (hereinafter, also referred to as “(A) component”) and (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 the component (B), and the first curable composition is a thermosetting composition. When it is a substance, the first curable composition contains a thermal polymerization initiator as the component (B). Such a first adhesive layer 2 polymerizes the component (A) by, for example, irradiating or heating a layer made of the first curable composition to polymerize the first curable composition. It is obtained by curing. That is, the first adhesive layer 2 may be composed of conductive particles 4 and an adhesive component 5 obtained by curing a component 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 the components (A) and (B), the adhesive component 5 may contain unreacted components (A) and (B), It may not 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 a resin component such as phenoxy resin such as PKHC, polyester urethane resin, polyurethane resin, acrylic rubber or the like. By using such a resin component, the melt viscosity at the temperature at which the second adhesive layer exhibits the minimum melt viscosity (for example, 100° C.) 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) by irradiation with light (for example, ultraviolet light) or heating. The component (A) may be a monomer, an oligomer or a 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) has at least one or more polymerizable groups. The polymerizable group is, for example, a group containing a polymerizable unsaturated double bond (ethylenically unsaturated bond). The polymerizable group has a viewpoint that a desired melt viscosity is easily obtained, a viewpoint that peeling between a circuit member and a circuit connecting portion is less likely to occur under a high temperature and high humidity environment, and a connection resistance reducing effect is further improved. From the viewpoint of more excellent connection reliability, a radical polymerizable group that reacts with a radical is preferable. That is, the component (A) is preferably a radically polymerizable compound. Examples of the radically polymerizable group include a vinyl group, an allyl group, a styryl group, an alkenyl group, an alkenylene group, a (meth)acryloyl group, and a maleimide group. The number of polymerizable groups contained in the component (A) is such that after polymerization, a desired melt viscosity is easily obtained, and peeling between the circuit member and the circuit connecting portion is less likely to occur in a high temperature and high humidity environment. Further, it may be 2 or more from the viewpoint that the effect of reducing the connection resistance is further improved and is more excellent in connection reliability, and may be 10 or less from the viewpoint of suppressing curing shrinkage during polymerization. Further, in order to balance the crosslink density and curing shrinkage, a polymerizable compound having a number of polymerizable groups within the above range may be used, and then a polymerizable compound outside the above range may be additionally used.

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

Examples of the (meth)acrylate compound include epoxy (meth)acrylate, (poly)urethane (meth)acrylate, methyl (meth)acrylate, polyether (meth)acrylate, polyester (meth)acrylate, polybutadiene (meth)acrylate, and 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) Examples thereof include acryloyloxyethyl acid phosphate.

Examples of the maleimide compound include 1-methyl-2,4-bismaleimidobenzene, N,N'-m-phenylene bismaleimide, N,N'-p-phenylene bismaleimide, and N,N'-m-toluylene bismaleimide. , N,N'-4,4-biphenylene bismaleimide, 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-diphenylmethane bismaleimide, 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 Examples thereof include den-bis(1-(4 maleimidophenoxy)-2-cyclohexylbenzene and 2,2′-bis(4-(4-maleimidophenoxy)phenyl)hexafluoropropane.

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

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

The component (A) is more likely to obtain a desired melt viscosity, is less likely to cause peeling between the circuit member and the circuit connecting portion in a high temperature and high humidity environment, and is further effective in reducing the connection resistance. However, a (meth)acrylate compound is preferable from the viewpoint of more excellent connection reliability. The component (A) may be a (poly)urethane (meth)acrylate compound (urethane (meth)acrylate compound or polyurethane (meth)acrylate compound) from the viewpoint of obtaining more excellent adhesive properties. In addition, the component (A) may be a (meth)acrylate compound having a high Tg skeleton such as a dicyclopentadiene skeleton from the viewpoint of obtaining more excellent adhesive properties.

The component (A) is more likely to obtain a desired melt viscosity, is less likely to cause peeling between the circuit member and the circuit connecting portion in a high temperature and high humidity environment, and is further effective in reducing the connection resistance. However, from the viewpoint of superior connection reliability, a compound in which a polymerizable group such as a vinyl group, an allyl group, or a (meth)acryloyl group is introduced into the terminal or side chain of a thermoplastic resin such as an acrylic resin, a phenoxy resin, or a polyurethane resin ( For example, it may be polyurethane (meth)acrylate). In this case, the weight average molecular weight of the component (A) may be 3,000 or more, 5,000 or more, and 10,000 or more from the viewpoint of excellent balance between crosslink density and curing shrinkage. The weight average molecular weight of the 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 a gel permeation chromatograph (GPC) using a calibration curve based on standard polystyrene according to the conditions described in the 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。］The component (A) preferably contains, as the (meth)acrylate compound, a radically polymerizable compound having a phosphoric acid ester structure represented by the following general formula (1). In this case, since the adhesive strength to the surface of the inorganic substance (metal or the like) is improved, it is suitable, for example, for bonding 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 a phosphoric acid ester structure can be obtained, for example, by reacting phosphoric anhydride with 2-hydroxyethyl (meth)acrylate. Specific examples of the radically polymerizable compound having a phosphoric acid ester structure include mono(2-(meth)acryloyloxyethyl) acid phosphate and di(2-(meth)acryloyloxyethyl) acid phosphate.

The content of the component (A) is such that a desired melt viscosity can be easily obtained, peeling between the circuit member and the circuit connecting portion is less likely to occur in a high temperature and high humidity environment, and a connection resistance reducing effect. Is further improved and connection reliability is more excellent, it may be 5% by mass or more, 10% by mass or more, and 20% by mass or more based on the total mass of the first curable composition. You may The content of the 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]
The component (B) is a radical by irradiation with light having a wavelength in the range of 150 to 750 nm, preferably light having a wavelength in the range of 254 to 405 nm, and more preferably light having a wavelength of 365 nm (for example, ultraviolet light). , A cation or anion-generating photopolymerization initiator (photoradical polymerization initiator, photocationic polymerization initiator or photoanion polymerization initiator), which is a thermal polymerization initiator (radical, cation or anion generating by heat ( It may be a thermal radical polymerization initiator, a thermal cationic polymerization initiator or a thermal anionic polymerization initiator). The component (B) is a radical from the viewpoint that a 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 is easier. It is preferably a polymerization initiator (a photo radical polymerization initiator or a thermal radical polymerization initiator). 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 the component (B).

The photo-radical polymerization initiator is decomposed by light to generate free radicals. That is, the photoradical polymerization initiator is a compound that generates radicals by applying light energy from the outside. Examples of the photoradical polymerization initiator include an oxime ester structure, a bisimidazole structure, an acridine structure, an α-aminoalkylphenone structure, an aminobenzophenone structure, an N-phenylglycine structure, an acylphosphine oxide structure, a benzyldimethylketal structure, and α-hydroxy. Examples thereof include compounds having a structure such as an alkylphenone structure. The photo-radical polymerization initiator is selected from the group consisting of an oxime ester structure, an α-aminoalkylphenone structure and an acylphosphine oxide structure from the viewpoint that a desired melt viscosity is easily obtained, and from the viewpoint that the effect of reducing the connection resistance is more excellent. It is preferable to have at least one structure of

Specific examples of the compound having an oxime ester structure include 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime and 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-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) and the like.

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

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

The thermal radical polymerization initiator is decomposed by heat to generate free radicals. That is, the thermal radical polymerization initiator is a compound that generates radicals by applying heat energy 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. To be When the one-minute half-life temperature is within this range, storage stability is further excellent, radical polymerizability is sufficiently high, and curing in a short time becomes possible.

Specific examples of the organic peroxide include 1,1,3,3-tetramethylbutylperoxy neodecanoate, di(4-t-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)peroxy. Dicarbonate, cumyl peroxy neodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate , T-butylperoxypivalate, 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-dimethylbutylperoxy neodecanoate, 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 peroxyisononanoate, t-amyl peroxybenzoate and the like.

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

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 quick-curing properties and the effect of reducing 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 storage stability and the effect of reducing connection resistance. It may be 10% by mass or less and 5% by mass or less.

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 that the desired viscosity can be easily obtained. It is more preferable to contain a photopolymerization initiator from the viewpoint of facilitating the production of the agent film.

[Component (C): conductive particles]
The component (C) is not particularly limited as long as it is a particle having conductivity, and is a metal particle composed of a metal such as Au, Ag, Ni, Cu, or a solder, a conductive carbon particle composed of conductive carbon, and the like. May be The component (C) may be coated conductive particles having a core containing non-conductive glass, ceramics, plastics (polystyrene, etc.), and a coating layer containing the metal or conductive carbon and coating the core. Good. Among these, coated conductive particles having a core containing metal particles formed of a heat-meltable metal or plastic and a coating layer containing metal or conductive carbon and coating 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 pressurizing, when the electrodes are electrically connected, the contact area between the electrode and the component (C) is And the conductivity between the electrodes can be further improved.

The component (C) may be insulation-coated conductive particles including the above-mentioned metal particles, conductive carbon particles, or coated conductive particles, and an insulating layer that covers the surface of the particles, containing an insulating material such as resin. Good. When the component (C) is an insulating coated conductive particle, even if the content of the component (C) is large, the surface of the particle is coated with the resin, so that a short circuit due to contact between the components (C) occurs. The generation can be suppressed, and the insulation between adjacent electrode circuits can be improved. As the component (C), one type of the various conductive particles described above may be used alone, or two or more types may be used in combination.

The maximum particle size of the component (C) needs to be smaller than the minimum distance between electrodes (the shortest distance between adjacent electrodes). The maximum particle size of the 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 the 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 the present specification, the particle size of the arbitrary 300 conductive particles (pcs) is measured by observation with a scanning electron microscope (SEM), and the obtained maximum value is the maximum particle size of the component (C). And When the component (C) does not have a spherical shape, such as when the component (C) has protrusions, the particle size of the component (C) is the diameter of the circle circumscribing the conductive particles in the SEM image.

The average particle size of the component (C) may be 1.0 μm or more, 2.0 μm or more, and 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The average particle size of the 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 the present specification, the particle size of the arbitrary 300 conductive particles (pcs) is measured by observation with a scanning electron microscope (SEM), and the average value of the obtained particle sizes is defined as the average particle size.

In the first adhesive layer 2, the component (C) is preferably uniformly dispersed. Particle density of the component (C) first in the adhesive layer 2, from the viewpoint of stable connection resistance is obtained, it may be at 100pcs / mm ² or more, may be at 1000pcs / mm ² or more, 2000pcs / mm It may be ^two or more. Particle density of the component (C) first in the adhesive layer 2, from the viewpoint of improving the insulating property between adjacent electrodes may be at 100000pcs / mm ² or less, may be at 50000pcs / mm ² or less, It may be 10,000 pcs/mm ² or less.

The content of the component (C) may be 0.1% by volume or more based on the total volume of the first adhesive layer, and may be 1% by volume or more, from the viewpoint that the conductivity can be further improved. It may be present and may be 5% by volume or more. The content of the component (C) may be 50 vol% or less, 30 vol% or less, and 20 vol% based on the total volume of the first adhesive layer from the viewpoint of easily suppressing a short circuit. % Or less. The content of the 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 other components other than the component (A), the component (B) and the component (C). Examples of other components include a thermoplastic resin, a coupling agent, and a filler. These components may be contained in the first adhesive layer 2.

Examples of the thermoplastic resin include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, and acrylic rubber. 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, it is possible to relieve the stress of the first adhesive layer, which occurs when the first curable composition is cured. Further, 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.

As the coupling agent, a (meth)acryloyl group, a mercapto group, an amino group, an imidazole group, a silane coupling agent having an organic functional group such as an epoxy group, a silane compound such as tetraalkoxysilane, a tetraalkoxy titanate derivative, a polydialkyl Examples thereof include titanate derivatives. When the first curable composition contains a coupling agent, the adhesiveness can be further improved. 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.

Examples of the filler include a non-conductive filler (for example, 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 the inorganic filler include metal oxide particles such as silica particles, alumina particles, silica-alumina particles, titania particles, and zirconia particles; and inorganic particles such as nitride particles. Examples of the organic filler include organic fine particles such as silicone fine particles, methacrylate-butadiene-styrene fine particles, acrylic-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 particle diameter of the conductive particles 4. The content of the filler may be, for example, 0.1 vol% or more, and may be 50 vol% or less, based on the total volume of the first curable composition.

The first curable composition may contain other additives such as a softener, an accelerator, a deterioration inhibitor, a colorant, a flame retardant, and a thixotropic agent. The content of these additives may be, for example, 0.1 to 10 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 the component (A) and the component (B) or in addition to the component (A) and the component (B). The thermosetting resin is a resin that is cured by heat and has at least one thermosetting group. The thermosetting resin is, for example, a compound that crosslinks by reacting with a curing agent by heat. As the thermosetting resin, one kind of compound may be used alone, or a plurality of kinds of compounds may be used in combination.

The thermosetting group, from the viewpoint that the desired melt viscosity is easily obtained, and from the viewpoint that the effect of reducing the connection resistance is further improved and the connection reliability is more excellent, for example, an epoxy group, an oxetane group, an isocyanate group, etc. Good.

Specific examples of the thermosetting resin include a bisphenol type epoxy resin which is a reaction product of epichlorohydrin and bisphenol A, F, AD and the like, and an epoxy which is a reaction product of epichlorohydrin and phenol novolac, cresol novolac and the like. Examples of the epoxy resin include novolac resins, naphthalene-based epoxy resins having a skeleton containing a naphthalene ring, various epoxy compounds having two or more glycidyl groups in one molecule such as glycidyl amine and glycidyl ether.

When a thermosetting resin is used 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 80% by mass or less. When a thermosetting resin is used 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 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. Examples of the curing agent for the thermosetting resin include a thermal radical generator, a thermal cation generator, and a thermal anion generator. The content of the curing agent may be, for example, 0.1 part 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 unreacted components such as the component (A) and the component (B) derived from the first curable composition. When the adhesive film 1 of the present embodiment is stored in a conventional storage member and stored and transported, the unreacted component (B) remains in the first adhesive layer 2, which causes storage and transportation. In the adhesive, a part of the second curable composition in the second adhesive layer 3 is cured, and peeling between the circuit member and the circuit connecting portion easily occurs in a high temperature and high humidity environment. It is presumed that problems such as a decrease in the effect of reducing the connection resistance of the film 1 will occur. Therefore, 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 from the viewpoint of suppressing the occurrence of the above-mentioned problems. It may be 10% by mass or less and 5% by mass or less. The content of the 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 adhesive film 1 may be housed in a housing member described later to suppress the occurrence of the above-mentioned problems.

The melt viscosity X of the first adhesive layer 2 at the temperature Ty at which the second adhesive layer 3 exhibits the minimum melt viscosity Y may be 1000 Pa·s or more from the viewpoint that peeling is less likely to occur, and 10000 Pa It may be s or more and 50,000 Pa·s or more. The melt viscosity X may be 10,000,000 Pa·s or less, 1,000,000 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, and the like.

The thickness d1 of the first adhesive layer 2 is 0.2 times or more the average particle size 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 the conductive particles are more likely to be crushed when the conductive particles are sandwiched between the electrodes facing each other during thermocompression bonding, and the connection resistance can be further reduced. The average particle size may be 0.8 times or less, and 0.7 times or less. From these viewpoints, the thickness d1 of the first adhesive layer 2 may be 0.2 to 0.8 times, or 0.3 to 0.7 times the average particle diameter of the conductive particles 4. Good. When the thickness d1 of the first adhesive layer 2 and the average particle diameter of the conductive particles 4 satisfy the above relationship, for example, as shown in FIG. 1, the conductive particles in the first adhesive layer 2 A part of 4 may project from the first adhesive layer 2 to the second adhesive layer 3 side. In this case, the boundary S between the first adhesive layer 2 and the second adhesive layer 3 is located at the space between the adjacent conductive particles 4 and 4. The conductive particles 4 are not exposed on the surface 2a of the first adhesive layer 2 on the side opposite to the second adhesive layer 3 side, and the surface 2a on the opposite side may be a flat surface.

The thickness d1 of the first adhesive layer 2 may be appropriately set according to the height of the electrode of the circuit member to be adhered and the like. 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 in the second adhesive layer 2 is exposed. The distance from the surface 2a on the side opposite to the adhesive layer 3 side to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 located at the spacing between the adjacent conductive particles 4 and 4 ( The distance indicated by d1 in FIG. 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. 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, the second curable composition. The second curable composition contains, for example, (a) a polymerizable compound (hereinafter, also referred to as (a) component) and (b) a polymerization initiator (hereinafter, also referred to as (b) component). The second curable composition may be a thermosetting composition containing a thermopolymerization initiator as the component (b), and is a photocurable composition containing a photopolymerization initiator as the component (b). Or 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 at the time of circuit connection, and is, for example, an uncured curable composition.

[Component (a): 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) by irradiation with light (eg, ultraviolet light) or heating. As the component (a), the compounds exemplified as the component (A) can be used. The component (a) reacts with radicals from the viewpoints of facilitating connection at a low temperature in a short time, easily obtaining a desired melt viscosity, and further improving the effect of reducing the connection resistance and being superior in connection reliability. It is preferably a radically polymerizable compound having a radically polymerizable group. Examples of preferable radically polymerizable compounds in the component (a) and preferable combinations of radically polymerizable compounds are the same as those in the component (A). When the component (a) is a radical-polymerizable compound and the component (B) in the first adhesive layer is a photo-radical polymerization initiator, the adhesive film is accommodated in the accommodation member described below to achieve adhesion. The curing of the second curable composition during storage or transportation of the agent film tends to be significantly suppressed.

The component (a) may be a monomer, an oligomer or a 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 the component (a) is 10% by mass based on the total mass of the second curable composition, from the viewpoint of reducing the connection resistance and easily obtaining the crosslink density required for improving the connection reliability. It may be above, may be 20 mass% or more, and may be 30 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 curing shrinkage during polymerization and obtaining good reliability, and 80 It may be not more than 70% by mass, and may be not more than 70% by mass.

[(B) component: polymerization initiator]
As the component (b), the same polymerization initiators as those exemplified as the component (B) can be used. The component (b) is preferably a radical polymerization initiator. Examples of the preferred radical polymerization initiator in the component (b) are the same as those in the component (B). As the component (b), one type of compound may be used alone, or a plurality of 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 a low temperature in a short time and from the viewpoint of superior connection reliability. , May be 0.5% by mass or more, and may be 1% by mass or more. From the viewpoint of pot life, the content of the component (b) may be 30% by mass or less, 20% by mass or less, and 10% by mass or less based on the total mass of the second curable composition. May be

[Other ingredients]
The second curable composition may further contain other components other than the component (a) and the component (b). Other components include, for example, thermoplastic resins, coupling agents, fillers, softening agents, accelerators, deterioration inhibitors, colorants, flame retardants, thixotropic agents and the like. The details of the other components are the same as the details 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 for curing the thermosetting resin. As the thermosetting resin and the curing agent, the same thermosetting resin and curing agent as the thermosetting resin and curing agent exemplified as the 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 80% by mass or less. When a thermosetting resin is used 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 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 0% by mass, based on the total mass of the second adhesive layer. The second adhesive layer 3 preferably does not contain the conductive particles 4.

The minimum melt viscosity Y of the second adhesive layer 3 may be 50 Pa·s or more, 100 Pa·s or more, and 300 Pa·s or more from the viewpoint of obtaining excellent blocking resistance. .. The minimum melt viscosity Y may be 100,000 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, for example, 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 electrode of the circuit member to be adhered and the like. 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 adhesive layer 3 is not exposed. The distance from the surface 3a on the side opposite to the adhesive layer 2 side to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 which are located in the space between the adjacent conductive particles 4 and 4 ( The distance indicated by d2 in FIG. 1) is the thickness of the second adhesive layer 3.

Ratio of the thickness d1 of the first adhesive layer 2 to the thickness d2 of the second adhesive layer 3 (thickness d1 of the first adhesive layer 2/thickness d2 of the second adhesive layer 3) May be 1 or more and 1000 or less 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.

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

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

For example, the adhesive film for circuit connection may be composed of two layers of a first adhesive layer and a second adhesive layer, and other than the first adhesive layer and the second adhesive layer. It may be composed of three or more layers including the layer (for example, the 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, and the first adhesive layer or the second adhesive layer. It may be a layer having physical properties similar to those described above (for example, melt viscosity), and may be a layer having thickness similar to that described above for the first adhesive layer or the second adhesive layer. .. The circuit connecting adhesive film may further include, for example, a third adhesive layer on a surface of the first adhesive layer opposite to the second adhesive layer. That is, the circuit connecting adhesive film is formed by laminating the second adhesive layer, the first adhesive layer, and the third adhesive layer in this order, for example. In this case, the third adhesive layer is made of, for example, a second curable composition (for example, a thermosetting composition) similarly to the second adhesive layer.

Further, the adhesive film for circuit connection of the above embodiment is an anisotropic conductive adhesive film having anisotropic conductivity, the adhesive film for circuit connection, the conductive film does not have anisotropic conductivity It may be an adhesive film.

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

In the first preparation step, for example, the first adhesive layer 2 is prepared by forming the first adhesive layer 2 on the base material to obtain the first adhesive film. Specifically, first, the component (A), the component (B) and the component (C), and other components added as necessary are added to an organic solvent and dissolved by stirring, mixing, kneading, etc. Alternatively, it is dispersed to prepare a varnish composition. After that, the varnish composition was applied on a release-treated substrate using a knife coater, a roll coater, an applicator, a comma coater, a die coater, and the like, and the organic solvent was volatilized by heating, and the varnish composition was applied on the substrate. Then, a layer made of the first curable composition is formed. Subsequently, the layer made 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. (Curing step). Thereby, the first adhesive film is obtained.

As the organic solvent used for the preparation of the varnish composition, those having the property of uniformly dissolving or dispersing each component are preferable, for example, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, etc. Is mentioned. These organic solvents can be used alone or in combination of two or more. Stirring and mixing and kneading at the time of preparing the varnish composition can be performed using, for example, a stirrer, a raker, a three-roll, a ball mill, a bead mill or a homodisper.

The base material 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 the base material include oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene/acetic acid. A base material (for example, a film) made of a vinyl copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer or 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 minutes or more and 10 minutes or less.

It is preferable to use irradiation light (for example, ultraviolet light) having a wavelength in the range of 150 to 750 nm for the irradiation of light in the curing step. The light irradiation can be performed using, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like. The light irradiation amount may be adjusted so that the melt viscosity ratio (X/Y) is 10 or more. The irradiation amount of light is, for example, an integrated light amount of light having a wavelength of 365 nm, which may be 100 mJ/cm ² or more, 200 mJ/cm ² or more, and 300 mJ/cm ² or more. The dose of light, for example, an accumulated light quantity of the wavelength 365nm light, may be at 10000 mJ / cm ² or less, may be at 5000 mJ / cm ² or less, may be at 3000 mJ / cm ² or less. The larger the light irradiation amount (total light amount of light), the larger the melt viscosity X, and the larger the melt viscosity ratio (X/Y).

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. or more and 300° C. or less for 0.1 minutes or more and 5000 minutes or less, and 50° C. or more and 150° C. or less for 0.1 minutes or more and 3000 minutes or less. The higher the heating temperature, the larger the melt viscosity X, and the larger the melt viscosity ratio (X/Y). Further, the longer the heating time is, the larger the melt viscosity X tends to be, and the melt viscosity ratio (X/Y) tends to be larger.

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

In the laminating step, the second adhesive layer 3 may be laminated on the first adhesive layer 2 by sticking the first adhesive film and the second adhesive film together. By applying the varnish composition obtained by using the component (a) and the component (b), and other components added as necessary on the adhesive layer 2, and evaporating the organic solvent, The second adhesive layer 3 may be laminated on the adhesive layer 2.

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

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

FIG. 2 is a schematic cross-sectional view showing the circuit connection structure according to the 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 11 a of the first circuit board 11. A second circuit member 16 having the second circuit board 14 and a second electrode 15 formed on the main surface 14a of the second circuit board 14, and the first circuit member 13 and the second circuit member And a circuit connecting portion 17 which is disposed between the first electrode 12 and the second electrode 15 and 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 as or different from each other. The first circuit member 13 and the second circuit member 16 may be a glass substrate or a 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 formed of a semiconductor, an inorganic material such as glass or ceramic, an organic material such as polyimide or polycarbonate, a composite material such as glass/epoxy, or the like. The first electrode 12 and the second electrode 15 are 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 connecting portion 17 is formed by the adhesive film 1 described above. The circuit connecting portion 17 is made of, for example, a cured product of the adhesive film 1. The circuit connecting portion 17 is located, for example, on the first circuit member 13 side in the direction in which the first circuit member 13 and the second circuit member 16 are opposed to each other (hereinafter referred to as “opposing direction”), and the above-described first circuit member 13 is provided. Located on the side of the second circuit member 16 in the facing direction, and the first region 18 made of a cured product of components (A) and (B) other than the conductive particles 4 of the curable composition of It is interposed between at least the first electrode 12 and the second electrode 15 and the second region 19 made of the cured product of the second curable composition containing the component a), the component (b) and the like. And conductive particles 4 electrically connecting the first electrode 12 and the second electrode 15 to each other. The circuit connecting portion does not have to have two regions like the first region 18 and the second region 19, and for example, the components other than the conductive particles 4 of the above-mentioned first curable composition may be used. It may consist of a cured product in which a cured product and a cured product of the above-mentioned second curable composition are mixed.

FIG. 3 is a schematic cross-sectional view showing the method for manufacturing the circuit connection structure 10. As shown in FIG. 3, the method for manufacturing the circuit connection structure 10 includes, for example, between a first circuit member 13 having a first electrode 12 and a second circuit member 16 having a second electrode 15. In which the above-mentioned adhesive film 1 is interposed, and the first circuit member 13 and the second circuit member 16 are thermocompression bonded to electrically connect the first electrode 12 and the second electrode 15 to each other. Equipped with.

Specifically, as shown in FIG. 3A, first, a first circuit including a first circuit board 11 and a first electrode 12 formed on a main surface 11 a of the first circuit board 11. A member 13 and a second circuit member 16 including a second circuit board 14 and 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 13 are arranged. The adhesive film 1 is placed 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 11 a of the first circuit member 13. To do. Next, the first adhesive film 1 is laminated so 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. The second circuit member 16 is arranged on the circuit member 13. In addition, for example, the adhesive film 1 may be laminated on the second circuit member 16 such 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 so 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. The first circuit member 13 is arranged on the circuit member 16.

Then, as shown in FIG. 3B, while heating the first circuit member 13, the adhesive film 1, and the second circuit member 16, the first circuit member 13 and the second circuit member 16 are separated from each other. By pressing 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 minimum melt viscosity Y. In the present embodiment, since the melt viscosity ratio (X/Y) of the adhesive film 1 is 10 or more, the second adhesive layer 3 can flow while the first adhesive layer 1 can flow during the thermocompression bonding. The agent layer 2 hardly flows. As a result, as shown by the arrow in FIG. 3B, the second adhesive layer flows so as to fill the gap between the second electrodes 15 and 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 bonded to each other. The circuit connection structure 10 shown in 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. When the second curable composition contains a photocurable composition, pressure and light irradiation or pressure, heat and light irradiation is performed instead of thermocompression bonding by heating, whereby the first circuit is formed. The member 13 and the second circuit member 16 may be joined.

<Adhesive film storage set>
FIG. 4 is a perspective view showing an adhesive film accommodation set of one embodiment. As shown in FIG. 4, the adhesive film accommodation set 20 includes an adhesive film 1 for circuit connection, a reel 21 around which the adhesive film 1 is wound, and an accommodation member 22 for accommodating the adhesive film 1 and the reel 21. And

As shown in FIG. 4, the adhesive film 1 has, for example, a tape shape. The tape-shaped adhesive film 1 is produced, for example, by cutting a sheet-shaped raw material into a long length with a width according to the application. A base material 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 winding core 23 around which the adhesive film 1 is wound, and a second side plate 25 arranged so as to face the first side plate 24 with the winding core 23 interposed therebetween. Prepare

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

The 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, for example, plastic and has an annular shape with a thickness similar to the width of the adhesive film 1. The winding core 23 is fixed to the inner side surface of the first side plate 24 so as to surround the opening of the first side plate 24. Further, a shaft hole 26, which is a portion into which a rotation shaft of a winding device or a feeding device (not shown) is inserted, is provided at the center of the reel 21. 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 container containing a desiccant may be fitted into the shaft hole 26.

The second side plate 25 is a circular plate made of, for example, plastic, like the first side plate 24, and has a circular cross section with the same diameter as the opening of the first side plate 24 at the central portion of the second side plate 25. Is provided.

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

The housing member 22 has a visual recognition portion 28 that allows the interior of the housing member 22 to be viewed from the outside. The accommodating member 22 shown in FIG. 4 is configured such that the entire accommodating 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 visual recognition 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 portion 28 can be obtained by making a sample by cutting the visible portion 28 into 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 portion 28, various information such as the product name, lot number, and expiration date attached to the reel 21 inside the housing member 22 can be confirmed from the outside of the housing member 22. be able to. As a result, it can be expected that mixing of different products is prevented and the efficiency of sorting work is improved.

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

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

The visual recognition portion 28 (accommodation 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 having a wavelength of 365 nm in the visual recognition portion 28. Such a material may be composed of one kind of component, or may be composed of plural kinds of components. Examples of the material include low density polyethylene, linear low density polyethylene, polycarbonate, polyester, acrylic resin, polyamide, glass and the like. These materials may include a UV absorber. The visual recognition portion 28 may have a laminated structure formed by laminating a plurality of layers having different light transmittances. In this case, each layer forming the visual recognition portion 28 may be made of the above-mentioned materials.

At the time of accommodation, the insertion port 27 may be hermetically closed by, for example, being closed by a sealing machine or the like in order to prevent air from entering from the outside. In this case, it is preferable to suck and remove the air in the accommodation member 22 before closing the insertion port 27. It can be expected that the humidity inside the housing member 22 will be reduced from the initial stage of housing and that the invasion 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, and the side plate 24 of the reel 21. , 25 can be prevented from being damaged on the outer side surface.

In the above-described embodiment, the housing member is configured such that the entire housing member serves as the visual recognition portion, but in another embodiment, the housing member has the visual recognition portion in a part of the housing member. Good. For example, the accommodating member may have a rectangular visual recognition portion substantially at the center of the side surface of the accommodating member. In this case, the portion of the housing member other than the visible portion may be black so as not to transmit ultraviolet light and visible light, for example.

Further, in the above embodiment, the shape of the accommodation member is a bag shape, but the accommodation member may be, for example, a box shape. It is preferable that the accommodating member has a notch for opening. In this case, the opening work during use becomes easy.

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to the examples.

<Synthesis of polyurethane acrylate (UA1)>
In a reaction vessel equipped with a stirrer, a thermometer, a reflux cooling tube having a calcium chloride drying tube, and a nitrogen gas introducing tube, poly(1,6-hexanediol carbonate) (trade name: Duranol T5652, manufactured by Asahi Kasei Chemicals Corporation) , 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. Next, after sufficiently introducing nitrogen gas into the reaction vessel, the inside of the reaction vessel was heated to 70 to 75° C. to cause a 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 the mixture was reacted at 70° C. for 6 hours in an air atmosphere. Thereby, polyurethane acrylate (UA1) was obtained. The weight average molecular weight of the polyurethane acrylate (UA1) was 15,000. The weight average molecular weight was measured by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene according to the following conditions.
(Measurement condition)
Device: Tosoh Corp. GPC-8020
Detector: RI-8020 manufactured by Tosoh Corporation
Column: Hitachi Chemical Co., Ltd. Gelpack GLA160S+GLA150S
Sample concentration: 120mg/3mL
Solvent: Tetrahydrofuran Injection volume: 60 μL
Pressure: 2.94×10 ⁶ Pa (30 kgf/cm ² )
Flow rate: 1.00 mL/min

<Production of conductive particles>
A layer made of nickel was formed on the surface of the polystyrene particles so that the layer had a thickness of 0.2 μm. In this way, 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 of first curable composition (varnish composition)>
The components shown below were mixed in the blending 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 (volume %) of the conductive particles and the content (volume %) of the filler shown in Table 1 are content based on the total volume of the first curable composition.
(Polymerizable compound)
A1: Dicyclopentadiene type diacrylate (trade name: Light acrylate DCP-A, manufactured by Toagosei Co., Ltd.)
A2: Polyurethane acrylate synthesized as described above (UA1)
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: Niper 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.)
(Coupling agent)
E1:3-methacryloxypropyltrimethoxysilane (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.)
(Filling material)
F1: Silica fine particles (trade name: R104, manufactured by Nippon Aerosil Co., Ltd., average particle diameter (primary particle diameter): 12 nm, specific gravity: 2)
(solvent)
G1: Methyl ethyl ketone

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

(Example 1)
[Preparation of First Adhesive Film]
The 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 made of the first curable composition 1 having a thickness (thickness after drying) of 2 μm on the PET film. Next, the layer made 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 , and the polymerizable compound was polymerized. Thereby, the 1st curable composition 1 was hardened and the 1st adhesive bond layer was formed. By the above operation, a first adhesive film having a 2 μm-thick first adhesive layer on the 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]
The varnish of the second curable composition 1 was applied onto a PET film having a thickness of 50 μm using a coating device. Next, hot air drying was performed at 70° C. for 3 minutes to form a second adhesive layer (layer made of the second curable composition 1) having a thickness of 10 μm on the PET film. By the above operation, a second adhesive film having the second adhesive layer on the PET film was obtained.

[Measurement of melt viscosity]
The melt viscosity of the first adhesive layer and the minimum melt viscosity of the second adhesive layer at the temperature at which the second adhesive layer exhibits the minimum melt viscosity were measured by the following methods. Specifically, first, the first adhesive film and the second adhesive film were laminated with a roll laminator while being heated at 40° C. to have a thickness of 200 μm. Then, it cut|disconnected to 0.8 cm(phi) and obtained the test piece. Then, 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: measurement temperature: 0 to 200° C., heating rate: 10° C./min, frequency: 10 Hz, strain: 0.5%.

The temperature at which the second adhesive layer exhibits the minimum melt viscosity (temperature Ty) was 103°C. The melt viscosity (melt viscosity X) of the first adhesive layer at the temperature Ty was 6×10 ⁴ Pa·s. The minimum melt viscosity (minimum 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 measurement, 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 heating at 40° C. together with the PET film as the base material. In this way, an adhesive film for circuit connection with a substrate, which includes a two-layered adhesive film for circuit connection in which the first adhesive layer and the second adhesive layer are laminated, was produced.

[Fabrication of circuit connection structure]
A thin film electrode including a COF (made by FLEXSEED) having a pitch of 25 μm and a thin film electrode (height: 1200 Å) made of amorphous indium tin oxide (ITO) on a glass substrate via the produced adhesive film for circuit connection. A glass substrate (manufactured by Geomatec Co., Ltd.) and a thermocompression bonding device (heating method: constant heat type, manufactured by Taiyo Kikai Seisakusho Co., Ltd.) are used to heat and pressurize at 170° C. and 6 MPa for 4 seconds to obtain a width. A circuit connecting structure (connecting structure) having a circuit connecting portion formed of an adhesive film for circuit connection was prepared by connecting over 1 mm. At the time of connection, the adhesive film for circuit connection was arranged on the glass substrate so that the surface of the adhesive film for circuit connection 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, and peeling evaluation was performed. Specifically, the area (peeling area) where peeling has occurred between the glass substrate with the thin film electrode and the circuit connecting portion was measured. The high-temperature and high-humidity test was performed by leaving it in a constant temperature and humidity tank at 85° C. and 85% RH for 200 hours. The results are shown in Table 3.

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

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. The case where the film was drawn out without any problems was evaluated as A, and the case where a problem such as sticking (blocking) to the substrate during the drawing occurred was taken as B. The results are shown in Table 3.

(Example 2)
An adhesive film for circuit connection and a circuit connection structure were obtained 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 subjected to melt viscosity measurement, peeling evaluation and blocking resistance evaluation in the same manner as in Example 1. The results are shown in Table 3.

(Example 3)
The first curable composition 2 was used in place of the first curable composition 1, and the first curable composition was used instead of light irradiation when producing the first adhesive film. An adhesive film for circuit connection and a circuit connection structure were produced in the same manner as in Example 1 except that the layer formed of the object 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. The results are shown in Table 3.

(Example 4)
The first curable composition 2 was used in place of the first curable composition 1, and the first curable composition was used instead of light irradiation when producing the first adhesive film. An adhesive film for circuit connection and a circuit connection structure were prepared in the same manner as in Example 1 except that the layer formed of the object 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. The results are shown in Table 3.

(Example 5)
The first curable composition 2 was used in place of the first curable composition 1, and the first curable composition was used instead of light irradiation when producing the first adhesive film. An adhesive film for circuit connection and a circuit connection structure were prepared in the same manner as in Example 1 except that the layer made of the object 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. The results are shown in Table 3.

(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 production of the first adhesive film (the first curable composition). Melt viscosity measurement was carried out in the same manner as in Example 1 except that the layer made of the composition 2 was not cured) and the adhesive film for circuit connection and the circuit connection structure were prepared in the same manner as in Example 1. The peeling evaluation and the blocking resistance evaluation were performed. The results are shown in Table 4.

(Comparative example 2)
An adhesive film for circuit connection and a circuit connection structure were made in the same manner as in Example 1 except that light was irradiated so that the integrated light amount was 50 mJ/cm ² when producing the first adhesive film. A body was prepared and subjected to melt viscosity measurement, peeling evaluation and blocking resistance evaluation in the same manner as in Example 1. The results are shown in Table 4.

(Comparative example 3)
The first curable composition 2 was used in place of the first curable composition 1, and the first curable composition was used instead of light irradiation when producing the first adhesive film. An adhesive film for circuit connection and a circuit connection structure were prepared in the same manner as in Example 1 except that the layer formed of the object 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. The results are shown in Table 4.

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

Claims (10)

A first adhesive layer containing conductive particles; and a second adhesive layer laminated on the first adhesive layer,
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 minimum melt viscosity to the minimum melt viscosity of the second adhesive layer is 10 or more. Adhesive film. The first adhesive layer comprises a cured product of the first curable composition,
The adhesive film for circuit connection according to claim 1, wherein the first curable composition contains a radically polymerizable compound having a radically polymerizable group. The second adhesive layer comprises a second curable composition,
The adhesive film for circuit connection according to claim 1 or 2, wherein the second curable composition contains a radically polymerizable compound having a radically polymerizable group. The adhesive film for circuit connection according to claim 1, wherein the thickness of the first adhesive layer is 0.2 to 0.8 times the average particle size of the conductive particles. .. A preparing step of preparing a first adhesive layer,
A laminating step of laminating a second adhesive layer made of a second curable composition on the first adhesive layer,
In the preparing step, the layer 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. Including a curing step to obtain
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 minimum melt viscosity to the minimum melt viscosity of the second adhesive layer is 10 or more. A method for producing an adhesive film for circuit connection, which comprises curing the first curable composition so that The method for producing an adhesive film for circuit connection according to claim 5, wherein the first curable composition contains a radically polymerizable compound having a radically polymerizable group. The method for producing an adhesive film for circuit connection according to claim 5 or 6, wherein the second curable composition contains a radically polymerizable compound having a radically polymerizable group. The thickness of the said 1st adhesive agent layer is 0.2-0.8 times the average particle diameter of the said electroconductive particle, The adhesive film for circuit connections as described in any one of Claims 5-7. Manufacturing method. The adhesive film for circuit connection according to any one of claims 1 to 4 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode. And a method for manufacturing a circuit connection structure, which comprises the step of 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 connecting adhesive film according to any one of claims 1 to 4, and a housing member for housing the adhesive film,
The accommodating member has a visual recognition portion that allows the interior of the accommodating member to be visually recognized from the outside,
An adhesive film accommodation set, wherein the visible portion has a transmittance of light having a wavelength of 365 nm of 10% or less.

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