Adhesive film for circuit connection, adhesive composition for circuit connection, circuit connection structure and method for producing the same

Abstract

An adhesive film for circuit connection contains electroconductive particles, and includes, in the film thickness direction, a region A containing a cationically polymerizable compound, a thermal cationic polymerization initiator, and an ion scavenger. The cationically polymerizable compound includes an epoxy compound. The thermal cationic polymerization initiator contains an anirinium salt. The ion scavenger includes one or more metal compounds selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide.

Description

[Technical Field]

[0001] The present disclosure relates to an adhesive film for circuit connection, an adhesive composition for circuit connection, a circuit connection structure, and a method for producing the same. [Background technology]

[0002] In recent years, the display industry has seen a paradigm shift in display module technology from liquid crystal displays to organic light-emitting diodes (LEDs), which has led to changes in the materials that make up panels.

[0003] Conventional liquid crystal displays use glass substrates as their substrates, with metals such as aluminum used for the underlying circuit and ITO (indium tin oxide) used for the surface electrodes as circuit materials formed on the glass substrate. On the other hand, organic LEDs use flexible plastic substrates such as polyimide substrates as their substrates, with Ti being the mainstream material for the circuits formed on the plastic substrates. Furthermore, a pressure-sensitive adhesive layer and a flexible member such as a polyethylene terephthalate (PET) substrate are typically disposed on the underside of the polyimide substrate to provide flexibility (see, for example, Patent Document 1).

[0004] In liquid crystal displays, from the viewpoints of fine pitch, light weight and thinness, so-called COG (chip on glass) mounting is adopted, in which various electronic components such as driver ICs are mounted directly on the glass substrate of the display panel. Also, as a COG mounting method, for example, a method is used in which a circuit connection structure is obtained by thermocompression bonding a liquid crystal driver IC onto a glass substrate via a circuit connection adhesive film having anisotropic conductivity in which conductive particles are dispersed in the adhesive. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2016-054288 Summary of the Invention [Problem to be solved by the invention]

[0006] Chip-on-plastic (COP) mounting, in which driver ICs and other components are directly mounted on plastic substrates, is also increasingly being adopted for organic LEDs. However, excessive pressure on plastic substrates can cause problems associated with plastic substrate deformation, such as deformation, cracking, and disconnection of Ti circuits mounted on polyimide substrates. Therefore, COG mounting, which uses an adhesive film for circuit connection, typically applies an area-equivalent pressure of 50 to 100 MPa to the bump electrodes of the IC chip. However, in COP mounting of organic LEDs, low pressure, e.g., 40 MPa or less, is preferred to prevent circuit disconnection. Mounted structures fabricated under such low pressure conditions tend to have high connection resistance between opposing electrodes, making it difficult to achieve sufficient electrical conductivity.

[0007] On the other hand, bumps in IC chips are becoming increasingly dense, and there is a need to ensure high insulation between adjacent circuits. However, the inventors' research has revealed that in packaged bodies made using circuit connection adhesive films containing conductive particles, for example, when the adhesive curing system is a cationic-epoxy curing system, the insulation resistance between adjacent circuits tends to decrease after high-temperature, high-humidity testing.

[0008] The main object of the present disclosure is to provide an adhesive film for circuit connection that can sufficiently ensure conductivity between opposing electrodes of a circuit connection structure and can sufficiently maintain insulation between adjacent circuits, even when connecting circuit components with low pressure. [Means for solving the problem]

[0009] In order to solve the above problems, one aspect of the present disclosure provides an adhesive film for circuit connection containing conductive particles, the adhesive film comprising, in the thickness direction of the film, a region A containing a cationically polymerizable compound, a thermal cationic polymerization initiator, and an ion scavenger, wherein the cationically polymerizable compound comprises a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule, the thermal cationic polymerization initiator comprises an anilinium salt, and the ion scavenger comprises at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide.

[0010] This adhesive film for circuit connection can ensure sufficient conductivity between opposing electrodes of a circuit connection structure and maintain sufficient insulation between adjacent circuits, even when circuit components are connected at low pressure. The reasons for this effect are not entirely clear, but the inventors speculate as follows: The adhesive film for circuit connection according to the present disclosure has a cationic polymerization region containing a compound having one or more ring-opening polymerizable cyclic ether groups in its molecule, which provides the adhesive component with a high degree of expulsion, making it easier to expel adhesive components from between opposing electrodes and near conductive particles. Furthermore, when combined with the specific thermal cationic polymerization initiator, it exhibits curing properties with superior resistance to cure inhibition compared to other thermal cationic polymerization initiators, such as sulfonium salts. This suppresses the flow of conductive particles between opposing electrodes, thereby ensuring sufficient conductivity. Furthermore, the adhesive film for circuit connection has a region A containing the specific ion scavenger, which can capture ions, such as chloride ions, that reduce insulation, generated by conductive particles in the circuit connection structure, thereby maintaining sufficient insulation between adjacent circuits.

[0011] The conductive particles may be palladium plated. An adhesive film for circuit connection containing such conductive particles is more likely to exhibit low resistance when used with a circuit having a Ti surface.

[0012] From the viewpoint of pot life, the anilinium salt may be an anilinium salt having an anion containing boron as a constituent element.

[0013] The conductive particles may be unevenly distributed on one side of the film, which facilitates improving the efficiency of capturing the conductive particles when connecting a circuit.

[0014] Region A may include, in the thickness direction of the film, a region P further containing a cured product of a photocurable resin component, and conductive particles may be dispersed in region P. In this case, the flow of conductive particles during circuit connection can be suppressed, preventing the flowed conductive particles from bridging adjacent circuits and reducing insulation, and further increasing the efficiency of capturing conductive particles.

[0015] Another aspect of the present disclosure provides an adhesive film for circuit connection, comprising a first adhesive layer containing conductive particles, a cured product of a photocurable resin component, and a first thermosetting resin component, and a second adhesive layer provided on the first adhesive layer and containing a second thermosetting resin component. In the adhesive film for circuit connection, one or both of the first adhesive layer and the second adhesive layer further contain an ion scavenger, and one or both of the first thermosetting resin component and the second thermosetting resin component contain a cationically polymerizable compound and a thermal cationic polymerization initiator, the cationically polymerizable compound contains a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule, the thermal cationic polymerization initiator contains an anilinium salt, and the ion scavenger contains at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide.

[0016] This adhesive film for circuit connection can ensure sufficient conductivity between opposing electrodes of a circuit connection structure and maintain sufficient insulation between adjacent circuits, even when circuit components are connected at low pressure. Furthermore, because the first adhesive layer containing conductive particles contains a cured product of a photocurable resin component, the flow of conductive particles during circuit connection can be suppressed, preventing the flowed conductive particles from bridging adjacent circuits and reducing insulation, and further increasing the efficiency of capturing conductive particles.

[0017] The conductive particles may be palladium plated. An adhesive film for circuit connection containing such conductive particles is more likely to exhibit low resistance when used with a circuit having a Ti surface.

[0018] From the viewpoint of pot life, the anilinium salt may be an anilinium salt having an anion containing boron as a constituent element.

[0019] Another aspect of the present disclosure provides an adhesive composition for circuit connection containing a cationically polymerizable compound, a thermal cationic polymerization initiator, and an ion scavenger, wherein the cationically polymerizable compound comprises a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule, the thermal cationic polymerization initiator comprises an anilinium salt, and the ion scavenger comprises at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide.

[0020] This adhesive composition for circuit connection can be used to form region A in the adhesive film for circuit connection described above, or the first adhesive layer and / or second adhesive layer.

[0021] From the viewpoint of pot life, the anilinium salt may be an anilinium salt having an anion containing boron as a constituent element.

[0022] The adhesive composition for circuit connection may further contain conductive particles and may further contain a photocurable resin component. Such an adhesive composition for circuit connection can form the region P or the first adhesive layer in the adhesive film for circuit connection described above.

[0023] The conductive particles may have a palladium plating.

[0024] Another aspect of the present disclosure provides a method for manufacturing a circuit connection structure, comprising the steps of interposing the above-mentioned adhesive film for circuit connection between a first circuit member having a first electrode and a second circuit member having a second electrode, and thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other.

[0025] One of the first circuit member and the second circuit member may be an IC chip, and the other may be a plastic substrate having an electrode containing Ti.

[0026] Another aspect of the present disclosure provides a circuit connection structure comprising: a first circuit member having a first electrode; a second circuit member having a second electrode; and a circuit connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other, wherein the circuit connection portion comprises a cured product of the above-mentioned adhesive film for circuit connection.

[0027] One of the first circuit member and the second circuit member may be an IC chip, and the other may be a plastic substrate having an electrode containing Ti. [Effects of the Invention]

[0028] According to the present disclosure, it is possible to provide an adhesive film for circuit connection that can sufficiently ensure conductivity between opposing electrodes of a circuit connection structure and sufficiently maintain insulation between adjacent circuits, even when circuit components are connected to each other at low pressure. Such an adhesive film for circuit connection can be suitably used for COP mounting. Furthermore, according to the present disclosure, it is possible to provide an adhesive composition for circuit connection that is suitable for forming such an adhesive film for circuit connection. Furthermore, according to the present disclosure, it is possible to provide a circuit connection structure using the above-mentioned adhesive film for circuit connection, and a method for producing the same. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection. [Figure 2] FIG. 2 is a schematic cross-sectional view showing one embodiment of a circuit connection structure. [Figure 3] 3A and 3B are schematic cross-sectional views showing one embodiment of a method for producing a circuit connection structure, in which Fig. 3A and Fig. 3B are schematic cross-sectional views showing each step. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, identical or corresponding parts will be designated by the same reference numerals, and redundant explanations will be omitted. It should be noted that the present invention is not limited to the following embodiments. In this specification, the term "(meth)acryloyl group" refers to an acryloyl group or a methacryloyl group, and the same applies to other similar expressions such as (meth)acrylate. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. Furthermore, the lower and upper limits of a numerical range can be arbitrarily combined with the lower or upper limit of another numerical range. In the expression "A to B," the numerical values ​​A and B at both ends are included as the lower and upper limits, respectively, within the numerical range. In this specification, for example, the term "10 or more" means 10 and a number greater than 10, and this also applies when the numerical values ​​differ. Furthermore, for example, the term "10 or less" means 10 and a number less than 10, and this also applies when the numerical values ​​differ. In addition, unless otherwise specified, each component and material exemplified in this specification may be used alone or in combination of two or more. In this specification, the content of each component in a composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified.

[0031] [Adhesive film for circuit connection] The adhesive film for circuit connection of this embodiment contains conductive particles, and also includes, in the thickness direction of the film, a region A containing a cationically polymerizable compound, a thermal cationic polymerization initiator, and an ion scavenger. The conductive particles may be unevenly distributed on one side of the film, and region A may include, in the thickness direction of the film, a region P further containing a cured product of a photocurable resin component, and the conductive particles may be dispersed in region P. Region A may also include, in the thickness direction of the film, a region S containing a cationically polymerizable compound, a thermal cationic polymerization initiator, and an ion scavenger, but not containing a cured product of a photocurable resin component.

[0032] Fig. 1 is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection according to the present embodiment. The adhesive film for circuit connection 10 shown in Fig. 1 (hereinafter sometimes simply referred to as "adhesive film 10") comprises a first adhesive layer 1 containing conductive particles 4 and an adhesive component 5 containing a cured product of a photocurable resin component and a (first) thermosetting resin component, and a second adhesive layer 2 provided on the first adhesive layer 1 and containing a (second) thermosetting resin component.

[0033] The adhesive film for circuit connection of this embodiment will be described below with reference to FIG.

[0034] The adhesive film 10 has conductive particles 4 dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 can be an anisotropically conductive adhesive film for circuit connection (anisotropically conductive adhesive film). The adhesive film 10 can be interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and can be used to electrically connect the first electrode and the second electrode to each other by thermocompression bonding the first circuit member and the second circuit member.

[0035] <First adhesive layer> The first adhesive layer 1 contains conductive particles 4 (hereinafter sometimes referred to as "component (A)"), a cured product of a photocurable resin component (hereinafter sometimes referred to as "component (B)"), and a thermosetting resin component (hereinafter sometimes referred to as "component (C)"). The first adhesive layer 1 can be obtained, for example, by irradiating a composition layer made of a composition containing components (A), (B), and (C) with light energy to polymerize the components contained in component (B) and cure component (B). The first adhesive layer 1 contains component (A), a cured product of component (B), and an adhesive component 5 containing component (C). The cured product of component (B) may be a cured product obtained by completely curing component (B) or a cured product obtained by partially curing component (B). Component (C) is a component that can flow during circuit connection, such as an uncured curable resin component.

[0036] Component (A): Conductive particles Component (A) is not particularly limited as long as it is a conductive particle, and may be, for example, a metal particle composed of a metal such as Au, Ag, Pd, Ni, Cu, or solder, or a conductive carbon particle composed of conductive carbon. Component (A) may also be a coated conductive particle comprising a core containing non-conductive glass, ceramic, or plastic (e.g., polystyrene), and a coating layer containing the metal or conductive carbon that coats the core. Among these, component (A) is preferably a metal particle formed of a heat-fusible metal, or a coated conductive particle comprising a core containing plastic and a coating layer containing a metal or conductive carbon that coats the core. Such coated conductive particles can be easily deformed by heating or applying pressure to a cured product of the thermosetting resin component. Therefore, when electrically connecting electrodes, the contact area between the electrodes and component (A) can be increased, thereby further improving the conductivity between the electrodes.

[0037] The conductive particles can be palladium-plated to facilitate low resistance in circuits with a Ti surface. In this case, palladium plating can be provided on the outermost surface of the conductive particles. Specifically, conductive particles can be used in which the surface of a plastic core is Ni-plated and the outermost surface is displacement-plated with Pd. These conductive particles may have insulating particles supported on their surfaces to prevent short circuits between the conductive particles. Furthermore, to facilitate low resistance, a ceramic core material of 100 nm to 200 nm in size may be incorporated into the Ni plating process, followed by Pd plating, with insulating particles supported as needed.

[0038] Component (A) may be an insulating coated conductive particle comprising the above-mentioned metal particles, conductive carbon particles, or coated conductive particles, and an insulating layer containing an insulating material such as resin that coats the surface of the particles. When component (A) is an insulating coated conductive particle, even if the content of component (A) is high, the particle surface has an insulating layer, which can prevent short circuits caused by contact between components (A) and can also improve insulation between adjacent electrode circuits. Component (A) can be one of the above-mentioned various conductive particles, or a combination of two or more of them.

[0039] The maximum particle size of component (A) must be smaller than the minimum electrode spacing (the shortest distance between adjacent electrodes). From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of component (A) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less. In this specification, the particle size of 300 random conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the largest value obtained is defined as the maximum particle size of component (A). Note that when component (A) has protrusions or is not spherical, the particle size of component (A) is defined as the diameter of a circle circumscribing the conductive particle in an SEM image.

[0040] The average particle size of component (A) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The average particle size of component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less from the viewpoint of excellent dispersibility and conductivity. In this specification, the particle size of 300 random conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the average value of the particle sizes obtained is defined as the average particle size.

[0041] Component (A) is preferably uniformly dispersed in first adhesive layer 1. From the viewpoint of obtaining a stable connection resistance, the particle density of component (A) in adhesive film 10 is 100 particles / mm 2 More than 1000 pieces / mm 2More than 3000 pieces / mm 2 or more than 5000 pieces / mm 2 The particle density of component (A) in adhesive film 10 may be 100,000 particles / mm 3 or more from the viewpoint of improving the insulating properties between adjacent electrodes. 2 Below, 70000 pieces / mm 2 Below, 50000 pieces / mm 2 or less than 30,000 pieces / mm 2 It may be the following:

[0042] The content of component (A) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total mass of the first adhesive layer, from the viewpoint of further improving conductivity. The content of component (A) may be 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of the first adhesive layer, from the viewpoint of easily suppressing short circuits. When the content of component (A) is within the above range, the effects of the present invention tend to be significantly exhibited. The content of component (A) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0043] (B) Component: Photocurable resin component Component (B) is not particularly limited as long as it is a resin component that cures upon irradiation with light, but from the viewpoint of achieving better connection resistance, it may be a resin component that has radical curing properties. Component (B) may contain, for example, a radical polymerizable compound (hereinafter sometimes referred to as "component (B1)") and a photoradical polymerization initiator (hereinafter sometimes referred to as "component (B2)"). Component (C) may be a component consisting of components (C1) and (C2).

[0044] Component (B1): radical polymerizable compound Component (B1) is a compound that polymerizes due to radicals generated from component (B2) upon irradiation with light (e.g., ultraviolet light). Component (B1) may be either a monomer or a polymer (or oligomer) formed by polymerization of one or more monomers. Component (B1) may be used singly or in combination.

[0045] Component (B1) is a compound having a radically polymerizable group that reacts with radicals. Examples of the radically polymerizable group include (meth)acryloyl, vinyl, allyl, styryl, alkenyl, alkenylene, and maleimide groups. The number of radically polymerizable groups (functional groups) in component (B1) may be 2 or more, from the viewpoints of easily achieving a desired melt viscosity after polymerization, further improving the effect of reducing connection resistance, and providing superior connection reliability, and may be 10 or less, from the viewpoint of suppressing cure shrinkage during polymerization. Furthermore, in order to balance crosslink density and cure shrinkage, in addition to compounds having the number of radically polymerizable groups within the above range, compounds having the number of radically polymerizable groups outside the above range may be used.

[0046] From the viewpoint of suppressing the flow of the conductive particles, the component (B1) may contain, for example, a polyfunctional (difunctional or higher) (meth)acrylate. The polyfunctional (difunctional or higher) (meth)acrylate may be a difunctional (meth)acrylate, and the difunctional (meth)acrylate may be a difunctional aromatic (meth)acrylate.

[0047] Examples of polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, and 1,3-butane. aliphatic (meth)acrylates such as diol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, glycerin di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, and ethoxylated 2-methyl-1,3-propanediol di(meth)acrylate;Aromatic (meth)acrylates such as ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, ethoxylated propoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate, propoxylated bisphenol F di(meth)acrylate, ethoxylated propoxylated bisphenol F di(meth)acrylate, ethoxylated fluorene di(meth)acrylate, propoxylated fluorene di(meth)acrylate, and ethoxylated propoxylated fluorene di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated propoxylated trimethylolpropane tri(meth)acrylate, and pentaerythritol Aliphatic (meth)acrylates such as pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated propoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated propoxylated pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetraacrylate, and dipentaerythritol hexa(meth)acrylate; aromatic epoxy (meth)acrylates such as bisphenol-type epoxy (meth)acrylate, phenol novolac-type epoxy (meth)acrylate, and cresol novolac-type epoxy (meth)acrylate;

[0048] The content of the polyfunctional (difunctional or higher) (meth)acrylate may be, for example, 40 to 100 mass%, 50 to 100 mass%, or 60 to 100 mass%, based on the total mass of the (B1) component, from the viewpoint of achieving both the effect of reducing connection resistance and the suppression of particle flow.

[0049] The component (B1) may further contain a monofunctional (meth)acrylate in addition to a polyfunctional (difunctional or higher) (meth)acrylate. Examples of the monofunctional (meth)acrylate include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, butoxyethyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octylheptyl (meth)acrylate, and nonyl (meth)acrylate. Decyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethoxypolypropylene glycol (meth)acrylate, mono(2-(meth)acryloyloxy) Aliphatic (meth)acrylates such as diethyl succinate; benzyl (meth)acrylate, phenyl (meth)acrylate, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, 1-naphthoxyethyl (meth)acrylate, 2-naphthoxyethyl (meth)acrylate, phenoxypolyether aromatic (meth)acrylates such as ethylene glycol (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, phenoxy polypropylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-(o-phenylphenoxy)propyl (meth)acrylate, 2-hydroxy-3-(1-naphthoxy)propyl (meth)acrylate, and 2-hydroxy-3-(2-naphthoxy)propyl (meth)acrylate;Examples of such acrylates include (meth)acrylates having an epoxy group such as glycidyl (meth)acrylate, (meth)acrylates having an alicyclic epoxy group such as 3,4-epoxycyclohexylmethyl (meth)acrylate, and (meth)acrylates having an oxetanyl group such as (3-ethyloxetan-3-yl)methyl (meth)acrylate.

[0050] The content of the monofunctional (meth)acrylate may be, for example, 0 to 60 mass %, 0 to 50 mass %, or 0 to 40 mass % based on the total mass of the component (B1).

[0051] The cured product of component (B) may have a polymerizable group that reacts by a mechanism other than a radical. The polymerizable group that reacts by a mechanism other than a radical may be, for example, a cationically polymerizable group that reacts by a cation. Examples of the cationically polymerizable group include epoxy groups such as glycidyl groups, alicyclic epoxy groups such as epoxycyclohexylmethyl groups, and oxetanyl groups such as ethyloxetanylmethyl groups. A cured product of component (B) having a polymerizable group that reacts by a mechanism other than a radical can be introduced by using, as component (B), a (meth)acrylate having a polymerizable group that reacts by a mechanism other than a radical, such as a (meth)acrylate having an epoxy group, a (meth)acrylate having an alicyclic epoxy group, or a (meth)acrylate having an oxetanyl group. The mass ratio of the (meth)acrylate having a polymerizable group that reacts by other than radicals to the total mass of the component (B1) (mass (charge amount) of the (meth)acrylate having a polymerizable group that reacts by other than radicals / total mass (charge amount) of the component (B1)) may be, for example, 0 to 0.7, 0 to 0.5, or 0 to 0.3, from the viewpoint of improving reliability.

[0052] The component (B1) may contain other radically polymerizable compounds in addition to polyfunctional (difunctional or higher) and monofunctional (meth)acrylates. Examples of other radically polymerizable compounds include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, and nadimide derivatives. The content of other radically polymerizable compounds may be, for example, 0 to 40% by mass based on the total mass of the component (B1).

[0053] Component (B2): Photoradical polymerization initiator The component (B2) is a photopolymerization initiator that generates radicals when irradiated 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 (e.g., ultraviolet light). The component (B2) may be used alone or in combination.

[0054] The component (B2) decomposes under light to generate free radicals. That is, the component (B2) is a compound that generates radicals upon application of external light energy. The component (B2) may be a compound having 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 benzyl dimethyl ketal structure, an α-hydroxyalkylphenone structure, or the like. The component (B2) may be used alone or in combination. From the viewpoints of easily obtaining a desired melt viscosity and of achieving a superior effect of reducing connection resistance, the component (B2) may be a compound having at least one structure selected from the group consisting of an oxime ester structure, an α-aminoalkylphenone structure, and an acylphosphine oxide structure.

[0055] Specific examples of compounds having an oxime ester structure include 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(o-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime), and the like.

[0056] Specific examples of compounds having an α-aminoalkylphenone structure include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-morpholinophenyl)-butanone-1, and the like.

[0057] Specific examples of compounds having an acylphosphine oxide structure include bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0058] The content of the (B2) component may be, for example, 0.1 to 10 parts by mass, 0.3 to 7 parts by mass, or 0.5 to 5 parts by mass per 100 parts by mass of the (B1) component, from the viewpoint of suppressing the flow of the conductive particles.

[0059] The content of the cured product of component (B) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total mass of the first adhesive layer, from the viewpoint of suppressing the flow of conductive particles. The content of the cured product of component (B) may be 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total mass of the first adhesive layer, from the viewpoint of achieving low resistance in low-pressure mounting. When the content of the cured product of component (B) is within the above range, the effects of the present invention tend to be significantly exhibited. The content of component (B) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0060] (C) Component: Thermosetting resin component The component (C) may contain, for example, a cationic polymerizable compound (hereinafter sometimes referred to as "component (C1)") and a thermal cationic polymerization initiator (hereinafter sometimes referred to as "component (C2)"). The component (C) may be a component consisting of components (C1) and (C2). The first thermosetting resin component and the second thermosetting resin component refer to the thermosetting resin components contained in the first adhesive layer and the second adhesive layer, respectively. The types, combinations, and contents of the components contained in the first thermosetting resin component and the second thermosetting resin component (e.g., component (C1), component (C2), etc.) may be the same or different from each other.

[0061] Component (C1): Cationic polymerizable compound Component (C1) is a compound that crosslinks by reacting with component (C2) under heat. Component (C1) refers to a compound that does not have a radically polymerizable group that reacts with a radical, and is not included in component (B1). From the viewpoint of further improving the effect of reducing connection resistance and achieving better connection reliability, component (C1) may be a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule. Component (C1) may be used alone or in combination. The compound having one or more ring-opening polymerizable cyclic ether groups in the molecule may be, for example, at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds. From the viewpoint of easily obtaining a desired melt viscosity, component (C1) preferably contains both at least one oxetane compound and at least one alicyclic epoxy compound.

[0062] The oxetane compound as component (C1) can be any compound that has an oxetanyl group and no radical polymerizable group, and can be used without any particular limitation. Commercially available oxetane compounds include ETERNACOLL OXBP (trade name, manufactured by Ube Industries, Ltd.), OXSQ, OXT-121, OXT-221, OXT-101, and OXT-212 (trade names, manufactured by Toagosei Co., Ltd.). These compounds can be used alone or in combination.

[0063] The alicyclic epoxy compound as component (C1) can be used without particular limitation as long as it has an alicyclic epoxy group (e.g., an epoxycyclohexyl group) and does not have a radical polymerizable group. Commercially available alicyclic epoxy compounds include, for example, EHPE3150, EHPE3150CE, CEL8010, CEL2021P, and CEL2081 (trade names, manufactured by Daicel Corporation). These compounds may be used alone or in combination.

[0064] Component (C2): thermal cationic polymerization initiator Component (C2) is a thermal polymerization initiator that generates an acid or the like when heated to initiate polymerization. Component (C2) may be a salt compound composed of a cation and an anion. Component (C2) is, for example, BF4 - , BR4 - (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups), PF6 - , SbF6 - , AsF6 - Examples of the anion include onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, and anilinium salts, each of which has an anion such as any of the above. These may be used alone or in combination.

[0065] From the viewpoint of storage stability, the component (C2) is, for example, an anion containing boron as a constituent element, i.e., BF4 - or BR4 - (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups). An anion containing boron as a constituent element may be a salt compound having BR4 - and more specifically, tetrakis(pentafluorophenyl)borate.

[0066] The onium salt as component (C2) may be, for example, an anilinium salt, since it is resistant to substances that can inhibit cationic curing. Examples of anilinium salt compounds include N,N-dialkylanilinium salts such as N,N-dimethylanilinium salt and N,N-diethylanilinium salt.

[0067] The component (C2) may be an anilinium salt having an anion containing boron as a constituent element. Commercially available products of such salt compounds include CXC-1821 (trade name, manufactured by King Industries).

[0068] The content of the (C2) component may be, for example, 0.1 to 25 parts by mass, 1 to 20 parts by mass, 3 to 18 parts by mass, or 5 to 15 parts by mass per 100 parts by mass of the (C1) component, from the viewpoint of ensuring the formability and curability of the adhesive film for forming the first adhesive layer.

[0069] The content of component (C) may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, based on the total mass of the first adhesive layer, from the viewpoint of ensuring the curability of the adhesive film for forming the first adhesive layer. The content of component (C) may be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of the first adhesive layer, from the viewpoint of ensuring the formability of the adhesive film for forming the first adhesive layer. When the content of component (C) is within the above range, the effects of the present invention tend to be significantly exhibited. The content of component (C) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0070] [Other ingredients] The first adhesive layer 1 may further contain other components in addition to the component (A), the cured product of the component (B), and the component (C). Examples of the other components include a thermoplastic resin (hereinafter sometimes referred to as "component (D)"), a coupling agent (hereinafter sometimes referred to as "component (E)"), a filler (hereinafter sometimes referred to as "component (F)"), an ion scavenger (hereinafter sometimes referred to as "component (G)"), etc.

[0071] Examples of component (D) include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylic rubber, and epoxy resin (solid at 25°C). These may be used alone or in combination. When a composition containing components (A), (B), and (C) further contains component (D), a composition layer (and further first adhesive layer 1) can be easily formed from the composition. Among these, component (D) may be, for example, a phenoxy resin.

[0072] From the viewpoint of resin removal properties during mounting, the weight average molecular weight (Mw) of component (D) may be, for example, 5,000 to 200,000, 10,000 to 100,000, 20,000 to 80,000, or 40,000 to 60,000. Mw refers to a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

[0073] The content of component (D) may be 1 mass % or more, 5 mass % or more, 10 mass % or more, or 20 mass % or more, and may be 70 mass % or less, 60 mass % or less, 50 mass % or less, or 40 mass % or less, based on the total mass of the first adhesive layer. The content of component (D) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0074] Examples of the (E) component include silane coupling agents having an organic functional group such as a (meth)acryloyl group, a mercapto group, an amino group, an imidazole group, or an epoxy group; silane compounds such as tetraalkoxysilane; tetraalkoxytitanate derivatives; and polydialkyltitanate derivatives. These may be used alone or in combination. The inclusion of the (E) component in the first adhesive layer 1 can further improve adhesion. The (E) component may be, for example, a silane coupling agent. The content of the (E) component may be 0.1 to 10% by mass, based on the total mass of the first adhesive layer. The content of the (E) component in the composition or composition layer (based on the total mass of the composition or composition layer) may be within the above-mentioned range.

[0075] Examples of the (F) component include non-conductive fillers (e.g., non-conductive particles). The (F) component may be either an inorganic filler or an organic filler. Examples of inorganic fillers include inorganic fine particles such as metal oxide fine particles, such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles; and metal nitride fine particles. Examples of organic fillers 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 may be used alone or in combination. The (F) component may be, for example, silica fine particles. The content of the (F) component may be 0.1 to 10% by mass, based on the total mass of the first adhesive layer. The content of the (F) component in the composition or composition layer (based on the total mass of the composition or composition layer) may be within the above-mentioned range.

[0076] Examples of component (G) include metal hydroxides and metal oxides. Component (G) may contain, for example, at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide. These metal compounds may be surface-treated to improve dispersibility in organic solvents.

[0077] From the viewpoint of maintaining insulation, component (G) may contain at least one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, and calcium hydroxide. From the viewpoint of obtaining even better maintaining insulation, the metal oxide is preferably at least one selected from the group consisting of silicon oxide, aluminum oxide, magnesium oxide, antimony oxide, tin oxide, titanium oxide, manganese oxide, and zirconium oxide. Component (G) may be used singly or in combination of two or more.

[0078] Commercially available ion scavengers include, for example, "IXEPLAS-A1," "IXEPLAS-A2," and "IXEPLAS-A3" (trade names, manufactured by Toagosei Co., Ltd.), "DHT-4A-2" (trade name, manufactured by Kyowa Chemical Industry Co., Ltd.), and "DHT-4A" (trade name, manufactured by Kyowa Chemical Industry Co., Ltd.).

[0079] Component (G) may be particles containing the above-mentioned metal compound. The primary particle diameter of component (G) may be 10 nm or more, or 20 nm or more, or 1000 nm or less, or 600 nm or less. The average primary particle diameter of component (G) can be measured, for example, using a scanning electron microscope.

[0080] Commercially available ion trapping agents can be used after removing aggregates and other impurities to make them suitable for coating thin films. For example, air classification or pulverization can be used to reduce the particle size distribution D95 after solvent dispersion to less than 5 μm. When D95 is less than 5 μm, the ion trapping agent particles can be easily dispersed, further improving the insulation between adjacent circuits. Furthermore, D95 can be reduced to less than 3 μm, further enhancing the aforementioned effects.

[0081] The content of component (G) may be 0.1 to 10% by mass, or 0.3 to 5% by mass, based on the total mass of the first adhesive layer (excluding the conductive particles and inorganic filler). If the content of component (G) is 0.1% by mass or more, it becomes easier to ensure that insulation between adjacent circuits is maintained, and if it is 10% by mass or less, the connection resistance between opposing electrodes is less likely to increase.

[0082] [Other additives] The first adhesive layer 1 may further contain other additives such as softeners, accelerators, anti-degradants, colorants, flame retardants, and thixotropic agents. The content of the other additives may be, for example, 0.1 to 10 mass % based on the total mass of the first adhesive layer. The content of the other additives in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0083] The thickness d1 of the first adhesive layer 1 may be, for example, 5 μm or less. The thickness d1 of the first adhesive layer 1 may be 4.5 μm or less or 4.0 μm or less. By making the thickness d1 of the first adhesive layer 1 5 μm or less, conductive particles can be captured more efficiently during circuit connection. The thickness d1 of the first adhesive layer 1 may be, for example, 0.1 μm or more, 0.5 μm or more, or 0.7 μm or more. The thickness d1 of the first adhesive layer 1 can be determined, for example, by sandwiching an adhesive film between two pieces of glass (thickness: approximately 1 mm), casting a resin composition consisting of 100 g of bisphenol A epoxy resin (trade name: JER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a curing agent (trade name: Epomount Curing Agent, manufactured by Refine Tech Co., Ltd.), polishing the cross section using a polishing machine, and measuring the thickness using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-Tech Science Corporation). 1, when a portion of the conductive particles 4 is exposed from the surface of the first adhesive layer 1 (for example, protruding toward the second adhesive layer 2), the distance from the surface 2a of the first adhesive layer 1 opposite the second adhesive layer 2 to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 located in the space between adjacent conductive particles 4,4 (the distance indicated by d1 in FIG. 1) is the thickness of the first adhesive layer 1, and the exposed portions of the conductive particles 4 are not included in the thickness of the first adhesive layer 1. The length of the exposed portions of the conductive particles 4 may be, for example, 0.1 μm or more and 5 μm or less.

[0084] <Second adhesive layer> The second adhesive layer 2 contains component (C). The components (C1) and (C2) used in component (C) (i.e., the second thermosetting resin component) in the second adhesive layer 2 are similar to the components (C1) and (C2) used in component (C) (i.e., the first thermosetting resin component) in the first adhesive layer 1, and therefore a detailed description thereof will be omitted here. The second thermosetting resin component may be the same as or different from the first thermosetting resin component.

[0085] The content of component (C) may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, based on the total mass of the second adhesive layer, from the viewpoint of maintaining reliability. The content of component (C) may be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of the second adhesive layer, from the viewpoint of preventing resin seepage problems in a reel, which is one embodiment of the supply form.

[0086] The second adhesive layer 2 may further contain other components and other additives than those in the first adhesive layer 1. Preferred embodiments of the other components and other additives are the same as those of the first adhesive layer 1.

[0087] The content of component (D) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, and may be 80% by mass or less, 60% by mass or less, or 40% by mass or less, based on the total mass of the second adhesive layer.

[0088] The content of the component (E) may be 0.1 to 10% by mass based on the total mass of the second adhesive layer.

[0089] The content of component (F) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total mass of the second adhesive layer, and may be 70% by mass or less, 50% by mass or less, or 30% by mass or less.

[0090] The content of component (G) may be 0.1 to 10% by mass, or 0.3 to 5% by mass, based on the total mass of the second adhesive layer (excluding the conductive particles and inorganic filler). If the content of component (G) is 0.1% by mass or more, it becomes easier to ensure that insulation between adjacent circuits is maintained, and if it is 10% by mass or less, the connection resistance between opposing electrodes is less likely to increase.

[0091] The content of the other additives may be, for example, 0.1 to 10% by mass based on the total mass of the second adhesive layer.

[0092] The thickness d2 of the second adhesive layer 2 may be appropriately set depending on the height of the electrodes of the circuit components to be bonded, etc. The thickness d2 of the second adhesive layer 2 may be 5 μm or more or 7 μm or more, and 15 μm or less or 11 μm or less, from the viewpoint of being able to sufficiently fill the space between the electrodes and seal the electrodes, thereby obtaining better connection reliability. The thickness d2 of the second adhesive layer 2 can be determined, for example, by a method similar to the method for measuring the thickness d1 of the first adhesive layer 1. Furthermore, when a portion of the conductive particles 4 is exposed from the surface of the first adhesive layer 1 (for example, protruding toward the second adhesive layer 2), the thickness of the second adhesive layer 2 is the distance (d2 in FIG. 1 ) from the surface 3 a of the second adhesive layer 2 opposite the first adhesive layer 1 side to the boundary S between the first adhesive layer 1 and the second adhesive layer 2, which is located in the space between adjacent conductive particles 4, 4.

[0093] The thickness of the adhesive film 10 (the sum of the thicknesses of all layers constituting the adhesive film 10; in Figure 1, the sum of the thickness d1 of the first adhesive layer 1 and the thickness d2 of the second adhesive layer 2) may be, for example, 5 μm or more or 8 μm or more, and may be 30 μm or less or 20 μm or less.

[0094] The adhesive film for circuit connection of this embodiment contains conductive particles and also includes a region A containing components (C1), (C2), and (G), where in region A, component (C1) contains a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule, component (C2) contains an anilinium salt, and component (G) contains at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide. An adhesive film for circuit connection having such a region A can ensure sufficient conductivity between opposing electrodes of a circuit connection structure and maintain sufficient insulation between adjacent circuits. In the adhesive film 10, for example, the first adhesive layer and the second adhesive layer may be the above-mentioned region A, or one of the first adhesive layer and the second adhesive layer may be the above-mentioned region A.

[0095] When the first adhesive layer and the second adhesive layer are region A, the range of region A in the thickness direction of the film can be the same as the sum of the thickness d1 of the first adhesive layer 1 and the thickness d2 of the second adhesive layer 2 described above.

[0096] Furthermore, when region A includes region P in the thickness direction of the film, which further contains a cured product of component (B), the first adhesive layer may be region P. In this case, conductive particles may be dispersed in region P. Furthermore, the range of region P in the thickness direction of the film can be set in the same manner as the thickness of the first adhesive layer described above. The content of each component in region P can also be set in the same manner as for the first adhesive layer.

[0097] Furthermore, when region A includes a region S in the thickness direction of the film that contains the specific component (C1), the specific component (C2), and the specific component (G) but does not contain a cured product of component (B), the second adhesive layer may be region S. In this case, the range of region S in the thickness direction of the film can be set in the same way as the thickness of the second adhesive layer described above. The content of each component in region S can also be set in the same way as for the second adhesive layer.

[0098] The minimum melt viscosity of the adhesive film 10 is 450 to 1600 Pa·s. The minimum melt viscosity of the adhesive film 10 may be 500 Pa·s or more, 600 Pa·s or more, 700 Pa·s or more, or 800 Pa·s or more. When the minimum melt viscosity of the adhesive film 10 is 450 Pa·s or more, deformation of the plastic substrate during thermocompression bonding is suppressed, making it possible to prevent circuit breakage. The minimum melt viscosity of the adhesive film 10 may be 1500 Pa·s or less, 1400 Pa·s or less, 1300 Pa·s or less, 1200 Pa·s or less, 1100 Pa·s or less, or 1000 Pa·s or less. When the minimum melt viscosity of the adhesive film 10 is 1600 Pa·s or less, deterioration in resin expulsion during circuit connection can be suppressed, thereby reducing the connection resistance between opposing electrodes of the circuit connection structure and ensuring good electrical conductivity. The minimum melt viscosity of the adhesive film can be determined, for example, by the following method. (Method for measuring minimum melt viscosity) Each adhesive film is laminated with a laminator to a thickness of 500 μm or more to obtain a laminate. The release-treated PET is peeled from the resulting laminate and cut into a 10.0 mm × 10.0 mm sample to obtain a measurement sample. The minimum melt viscosity of the resulting measurement sample is measured using a viscoelasticity measuring device (product name: ARES-G2, manufactured by TA Instruments, heating rate: 10 °C / min).

[0099] In the adhesive film 10, the second adhesive layer 2 is usually thicker than the first adhesive layer 1. Therefore, the minimum melt viscosity of the adhesive film 10 tends to vary depending on the second adhesive layer 2. The minimum melt viscosity of the adhesive film 10 can be adjusted, for example, by adjusting the type and content of the constituent components (particularly, component (D)) contained in the second adhesive layer 2. The minimum melt viscosity of the adhesive film 10 can also be adjusted, for example, by using a component (F) with a small particle size. The minimum melt viscosity of the adhesive film 10 tends to increase by using a component (F) with a small particle size.

[0100] In the adhesive film 10, conductive particles 4 are dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 is an anisotropically conductive adhesive film having anisotropic conductivity. The adhesive film 10 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and is used to electrically connect the first electrode and the second electrode to each other by thermocompression bonding the first circuit member and the second circuit member.

[0101] The adhesive film 10 can ensure sufficient electrical continuity between opposing electrodes of a circuit connection structure and maintain sufficient insulation between adjacent circuits, even when connecting circuit components with low pressure. Such an adhesive film for circuit connection can be suitably used for COP mounting. More specifically, it can be suitably used for connecting a plastic substrate on which circuit electrodes are formed in an organic EL display to an IC chip such as a driver IC.

[0102] Although the adhesive film of this embodiment has been described above, the present invention is not limited to the above embodiment.

[0103] The adhesive film may be, for example, composed of two layers, a first adhesive layer and a second adhesive layer, or may be composed of three or more layers including two layers, a first adhesive layer and a second adhesive layer. The adhesive film may further include, for example, a third adhesive layer provided on the side of the first adhesive layer opposite the second adhesive layer.

[0104] The third adhesive layer contains component (C). Components (C1) and (C2) used in component (C) (i.e., the third thermosetting resin component) in the third adhesive layer are similar to components (C1) and (C2) used in component (C) (i.e., the first thermosetting resin component) in the first adhesive layer 1, and therefore detailed description thereof will be omitted here. The third thermosetting resin component may be the same as or different from the first thermosetting resin component. The third thermosetting resin component may be the same as or different from the second thermosetting resin component.

[0105] The content of component (C) may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, based on the total mass of the third adhesive layer, from the viewpoint of imparting good transferability and peel resistance. The content of component (C) may be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of the third adhesive layer, from the viewpoint of imparting good half-cut properties and blocking resistance (suppression of resin bleeding from the reel).

[0106] The third adhesive layer may further contain other components and other additives than those in the first adhesive layer 1. From the viewpoint of achieving both the electrical conductivity between opposing electrodes and the ability to maintain insulation between adjacent circuits, the third adhesive layer may have the configuration of the above-mentioned region A or region S. Preferred aspects of the other components and other additives are the same as those of the first adhesive layer 1.

[0107] The content of component (D) may be 10% by mass or more, 20% by mass or more, or 30% by mass or more, and may be 80% by mass or less, 70% by mass or less, or 60% by mass or less, based on the total mass of the third adhesive layer.

[0108] The content of the component (E) may be 0.1 to 10% by mass based on the total mass of the third adhesive layer.

[0109] The content of component (F) may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total mass of the third adhesive layer, and may be 50% by mass or less, 40% by mass or less, or 30% by mass or less.

[0110] The content of component (G) may be 0.1 to 10% by mass, or 0.3 to 5% by mass, based on the total mass of the third adhesive layer (excluding the conductive particles and inorganic filler). If the content of component (G) is 0.1% by mass or more, it becomes easier to ensure that insulation between adjacent circuits is maintained, and if it is 10% by mass or less, the connection resistance between opposing electrodes is less likely to increase.

[0111] The content of the other additives may be, for example, 0.1 to 10% by mass based on the total mass of the third adhesive layer.

[0112] The thickness of the third adhesive layer may be appropriately set depending on the minimum melt viscosity of the adhesive film, the height of the electrodes of the circuit components to be bonded, etc. The thickness of the third adhesive layer is preferably smaller than the thickness d2 of the second adhesive layer 2. The thickness of the third adhesive layer may be 0.2 μm or more and 3.0 μm or less, from the viewpoint of being able to sufficiently fill the space between the electrodes and seal the electrodes, thereby obtaining better connection reliability. The thickness of the third adhesive layer can be determined, for example, by a method similar to the method for measuring the thickness d1 of the first adhesive layer 1.

[0113] When the first adhesive layer, the second adhesive layer, and the third adhesive layer are region A, the range of region A in the thickness direction of the film can be the same as the sum of the thicknesses of the first adhesive layer, the second adhesive layer, and the third adhesive layer. When the third adhesive layer is region S, the range of region S in the thickness direction can be the same as the thickness of the third adhesive layer.

[0114] The adhesive film for circuit connection in the above embodiment may be a conductive adhesive film that does not have anisotropic conductivity.

[0115] <Method of manufacturing an adhesive film for circuit connection> A method for producing an adhesive film for circuit connection according to one embodiment may include, for example, a step (first step) of irradiating a composition layer made of a composition containing components (A), (B), and (C) (first thermosetting resin component), and optionally component (G), with light to form a first adhesive layer, and a step (second step) of laminating a second adhesive layer containing component (C) (second thermosetting resin component) and optionally component (G) on the first adhesive layer. The production method may further include a step (third step) of laminating a third adhesive layer containing component (C) (third thermosetting resin component) and optionally component (G) on the layer of the first adhesive layer opposite the second adhesive layer. In this case, either the second step or the third step may be performed first. When the third step is performed first, the third adhesive layer is laminated on the side of the first adhesive layer opposite the side on which the second adhesive layer will be laminated.

[0116] In the first step, for example, a composition containing components (A), (B), and (C), as well as other components and additives such as component (G), if necessary, is dissolved or dispersed in an organic solvent by stirring, mixing, kneading, or the like to prepare a varnish composition (a first adhesive composition in varnish form). The varnish composition is then applied to a release-treated substrate using a knife coater, roll coater, applicator, comma coater, die coater, or the like, and the organic solvent is then volatilized by heating to form a composition layer on the substrate. The thickness of the final first adhesive layer (first adhesive film) can be adjusted by adjusting the amount of varnish composition applied. Subsequently, the composition layer is irradiated with light to cure component (B) in the composition layer, forming a first adhesive layer on the substrate. This first adhesive layer can be referred to as a first adhesive film.

[0117] The organic solvent used in preparing the varnish composition is not particularly limited as long as it has the property of being able to uniformly dissolve or disperse each component. Examples of such organic solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, etc. These organic solvents can be used alone or in combination of two or more. The stirring, mixing, or kneading in preparing the varnish composition can be carried out using, for example, a stirrer, a grinder, a three-roll mill, a ball mill, a bead mill, a homodisper, etc.

[0118] The substrate is not particularly limited as long as it has heat resistance sufficient to withstand the heating conditions required for volatilizing the organic solvent. Examples of such substrates include substrates (e.g., films) made of oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, and liquid crystal polymer.

[0119] The heating conditions for volatilizing the organic solvent from the varnish composition applied to the substrate can be appropriately set depending on the organic solvent used, etc. The heating conditions may be, for example, 40 to 120°C for 0.1 to 10 minutes.

[0120] A portion of the solvent may remain in the first adhesive layer without being removed. The content of the solvent in the first adhesive layer may be, for example, 10 mass % or less based on the total mass of the first adhesive layer.

[0121] For the light irradiation in the curing step, it is preferable to use irradiation light (for example, ultraviolet light) having a wavelength in the range of 150 to 750 nm. Light irradiation can be carried out using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, etc. The cumulative light amount of the light irradiation can be set appropriately, but is, for example, 500 to 3000 mJ / cm. 2 It may be.

[0122] The second step is a step of laminating a second adhesive layer on the first adhesive layer. In the second step, for example, a second adhesive layer is first formed on a substrate in the same manner as the first step, except that component (C) and other components and additives, such as component (G), which are added as needed, are used, and light irradiation is not performed, to obtain a second adhesive film. Next, the first adhesive film and the second adhesive film are bonded together to laminate the second adhesive layer on the first adhesive layer. In addition, in the second step, for example, a varnish composition (varnish-like second adhesive composition) obtained using component (C) and other components and additives, such as component (G), which are added as needed, is applied to the first adhesive layer, and the second adhesive layer can also be laminated on the first adhesive layer by volatilizing the organic solvent.

[0123] Examples of methods for bonding the first adhesive film and the second adhesive film include hot pressing, roll lamination, vacuum lamination, etc. Lamination can be carried out under temperature conditions of, for example, 0 to 80°C.

[0124] A portion of the solvent may remain in the second adhesive layer without being removed. The content of the solvent in the second adhesive layer may be, for example, 10 mass % or less based on the total mass of the second adhesive layer.

[0125] The third step is a step of laminating a third adhesive layer on the layer of the first adhesive layer opposite the second adhesive layer. In the third step, for example, first, a third adhesive layer is formed on a substrate in the same manner as in the second step to obtain a third adhesive film. Next, the third adhesive layer can be laminated on the layer of the first adhesive layer opposite the second adhesive layer by laminating the third adhesive film on the side of the first adhesive film opposite the second adhesive layer. In addition, in the third step, for example, a varnish composition (a varnish-like third adhesive composition) can also be applied to the layer of the first adhesive layer opposite the second adhesive layer, and the organic solvent can be volatilized, thereby laminating the third adhesive layer on the first adhesive layer. The lamination method and conditions are the same as in the second step.

[0126] A portion of the solvent may remain in the third adhesive layer without being removed. The content of the solvent in the third adhesive layer may be, for example, 10 mass % or less based on the total mass of the third adhesive layer.

[0127] <Adhesive composition for circuit connection> The adhesive composition for circuit connection of the present embodiment contains a cationically polymerizable compound, a thermal cationic polymerization initiator, and an ion scavenger, wherein the cationically polymerizable compound contains a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule, the thermal cationic polymerization initiator contains an anilinium salt, and the ion scavenger contains at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide.

[0128] The adhesive composition for circuit connection of this embodiment can form regions A, P, S, the first adhesive layer, the second adhesive layer, the third adhesive layer, etc. in the adhesive film for circuit connection described above.

[0129] The adhesive composition for circuit connection of this embodiment may further contain conductive particles and may further contain a photocurable resin component. Such an adhesive composition for circuit connection can form the region P or the first adhesive layer in the adhesive film for circuit connection described above.

[0130] The composition of the adhesive composition for circuit connection of this embodiment can be set in the same manner as the composition of the first adhesive layer, second adhesive layer, or third adhesive layer described above.

[0131] <Circuit connection structure and method for manufacturing the same> A circuit connection structure using the above-mentioned adhesive film 10 for circuit connection as the circuit connecting material and a method for producing the same will now be described.

[0132] Fig. 2 is a schematic cross-sectional view showing one embodiment of a circuit connection structure. As shown in Fig. 2, a circuit connection structure 20 includes a first circuit board 11 and a first circuit member 13 having a first electrode 12 formed on a main surface 11a of the first circuit board 11, a second circuit board 14 and a second circuit member 16 having a second electrode 15 formed on a main surface 14a of the second circuit board 14, and a circuit connection portion 17 disposed between the first circuit member 13 and the second circuit member 16 and electrically connecting the first electrode 12 and the second electrode 15 to each other.

[0133] The first circuit member 13 and the second circuit member 16 may be the same or different. The first circuit member 13 and the second circuit member 16 may be a glass or plastic substrate on which circuit electrodes are formed; a printed wiring board; a ceramic wiring board; a flexible wiring board; an IC chip such as a driving IC; or the like. The first circuit board 11 and the second circuit board 14 may be formed from an inorganic material such as a semiconductor, glass, or ceramic; an organic material such as polyimide or polycarbonate; or a composite material such as glass / epoxy. The first circuit board 11 may be a plastic substrate. The first circuit member 13 may be, for example, a plastic substrate (a plastic substrate made of an organic material such as polyimide, polycarbonate, polyethylene terephthalate, or cycloolefin polymer) on which circuit electrodes are formed, and the second circuit member 16 may be, for example, an IC chip such as a driving IC. The plastic substrate on which electrodes are formed may be a plastic substrate on which a display area is formed by, for example, a pixel driving circuit such as an organic TFT or a plurality of organic EL elements R, G, and B are regularly arranged in a matrix.

[0134] The first electrode 12 and the second electrode 15 may be electrodes containing metals such as gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, and titanium, or oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), and indium gallium zinc oxide (IGZO). The first electrode 12 and the second electrode 15 may be electrodes formed by laminating two or more of these metals, oxides, and the like. An electrode formed by laminating two or more of these metals, oxides, and the like may have two or more layers, or may have three or more layers. When the first circuit member 13 is a plastic substrate, the first electrode 12 may be an electrode having a titanium layer on its outermost surface. 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. FIG. 2 shows an embodiment in which the first electrode 12 is a circuit electrode and the second electrode 15 is a bump electrode.

[0135] The circuit connection portion 17 includes a cured product of the adhesive film 10. The circuit connection portion 17 may be made of a cured product of the adhesive film 10. For example, the circuit connection portion 17 has a first region 18 located on the first circuit member 13 side in the direction in which the first circuit member 13 and the second circuit member 16 face each other (hereinafter referred to as the "facing direction") and made of a cured product of the component (B) and a cured product of the component (C) and the like other than the conductive particles 4 in the first adhesive layer, a second region 19 located on the second circuit member 16 side in the facing direction and made of a cured product of the component (C) and the like in the second adhesive layer, and conductive particles 4 interposed at least between the first electrode 12 and the second electrode 15 to electrically connect the first electrode 12 and the second electrode 15 to each other. As shown in FIG. 2, the circuit connection portion 17 does not have to have two distinct regions between the first region 18 and the second region 19, but may have a single region formed by a mixture of the cured material derived from the first adhesive layer and the cured material derived from the second adhesive layer.

[0136] Examples of circuit connection structures include flexible organic electroluminescent color displays (organic EL displays) in which a plastic substrate on which organic EL elements are regularly arranged is connected to a drive circuit element that is a driver for displaying images, and touch panels in which a plastic substrate on which organic EL elements are regularly arranged is connected to a position input element such as a touchpad.The circuit connection structures can be applied to various monitors such as smartphones, tablets, televisions, vehicle navigation systems, and wearable devices; furniture; home appliances; and everyday items.

[0137] Fig. 3 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a circuit connection structure. Fig. 3(a) and Fig. 3(b) are schematic cross-sectional views showing each step. As shown in Fig. 3, the method for manufacturing a circuit connection structure 20 includes the steps of interposing the above-mentioned adhesive film 10 between a first circuit member 13 having a first electrode 12 and a second circuit member 16 having a second electrode 15, and thermocompression bonding the first circuit member 13 and the second circuit member 16 to electrically connect the first electrode 12 and the second electrode 15 to each other.

[0138] Specifically, as shown in FIG. 3(a), first, a first circuit member 13 including a first circuit board 11 and a first electrode 12 formed on the main surface 11a of the first circuit board 11, 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.

[0139] 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 adhesive film 10 is placed between the first circuit member 13 and the second circuit member 16. For example, as shown in FIG. 3( a), the adhesive film 10 is laminated onto the first circuit member 13 so that the first adhesive layer 1 faces the main surface 11a of the first circuit board 11. Next, the second circuit member 16 is placed on the first circuit member 13 on which the adhesive film 10 has been 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.

[0140] 3(b), the first circuit member 13 and the second circuit member 16 are heated while being pressed against each other in the thickness direction, thereby thermocompression-bonding the first circuit member 13 and the second circuit member 16. During this process, as indicated by the arrows in FIG. 3(b), the second adhesive layer 2 contains a flowable, uncured thermosetting component, so that it flows to fill the gaps between the second electrodes 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 via the conductive particles 4, and the first circuit member 13 and the second circuit member 16 are bonded to each other, thereby obtaining the circuit connection structure 20 shown in FIG. 2. In the manufacturing method of the circuit connection structure 20 of this embodiment, the first adhesive layer 1 can be said to be a layer in which a portion of it has been hardened by light irradiation, so that the flow of the conductive particles in the first adhesive layer 1 is suppressed, the first adhesive layer 1 hardly flows during the thermocompression bonding, and the conductive particles are efficiently captured between the opposing electrodes, thereby reducing the connection resistance between the opposing first electrode 12 and second electrode 15. Furthermore, if the thickness of the first adhesive layer is 5 μm or less, the conductive particles tend to be captured even more efficiently during circuit connection.

[0141] The heating temperature for thermocompression bonding can be set appropriately, but may be, for example, 50 to 190°C. The pressure to be applied is not particularly limited as long as it does not damage the adherend, but in the case of COP mounting, for example, the equivalent area pressure at the bump electrode may be 0.1 to 50 MPa, or 40 MPa or less, or may be 0.1 to 40 MPa. In the case of COG mounting, for example, the equivalent area pressure at the bump electrode may be 10 to 100 MPa. The heating and pressurizing time may be in the range of 0.5 to 120 seconds. [Example]

[0142] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0143] [Preparation of the first adhesive layer and the second adhesive layer] The materials shown below were used in producing the first adhesive layer and the second adhesive layer.

[0144] Component (A): Conductive particles A-1: The surface of the plastic core is plated with Ni, and the top surface is plated with Pd substitution plating. Conductive particles with an average particle size of 3.2 μm are used.

[0145] (B) Component: Photocurable resin component Component (B1): radical polymerizable compound B1-1: A-BPEF70T (ethoxylated fluorene-type di(meth)acrylate (bifunctional), manufactured by Shin-Nakamura Chemical Co., Ltd.), diluted with toluene to 70% nonvolatile content by mass. B1-2: Lipoxy VR-90 (bisphenol A type epoxy (meth)acrylate (bifunctional) (vinyl ester resin), manufactured by Showa Denko K.K.)

[0146] Component (B2): Photoradical polymerization initiator B2-1: Irgacure 907 (a compound with an α-aminoalkylphenone structure, manufactured by BASF), diluted with MEK to a non-volatile content of 10% by mass.

[0147] (C) Component: Thermosetting resin component Component (C1): Cationic polymerizable compound C1-1: ETERNACOLL OXBP (3-ethyl-3-hydroxymethyloxetane, manufactured by Ube Industries, Ltd.) C1-2: EHPE3150 (1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, manufactured by Daicel Corporation) C1-3: Celloxide 8010 (bi-7-oxabicyclo[4.1.0]heptane, manufactured by Daicel Corporation) C1-4: OX-SQ TX-100 (poly({3-[(3-ethyl-3-oxetanyl)methoxy]propyl}silsesquioxane) derivative, manufactured by Toagosei Co., Ltd.)

[0148] Component (C2): thermal cationic polymerization initiator C2-1: CXC-1821 (King Industries)

[0149] (D) Component: Thermoplastic resin D-1: Phenototo YP-50S (bisphenol A phenoxy resin, weight average molecular weight: 60,000, glass transition temperature: 84°C, manufactured by Nippon Steel Chemical & Material Co., Ltd.), diluted with MEK to a non-volatile content of 40% by mass. D-2: TOPR-300 (high Tg type epoxy resin, epoxy equivalent: 900-1,000, softening point: 120°C, manufactured by Nippon Steel Chemical & Material Co., Ltd.), diluted with MEK to a non-volatile content of 60% by mass. D-3: Phenototo ZX-1356-2 (bisphenol A and bisphenol F copolymer phenoxy resin, weight average molecular weight: 70,000, glass transition temperature: 71°C, manufactured by Nippon Steel Chemical & Material Co., Ltd.), diluted with MEK to a non-volatile content of 40% by mass.

[0150] Component (E): Coupling agent E-1: SH-6040 (3-glycidoxypropyltrimethoxysilane, manufactured by Dow Corning Toray Co., Ltd.)

[0151] (F) Component: Filler F-1: ADMAFINE SE2050 (silica fine particles, manufactured by Admatechs Co., Ltd.)

[0152] (G) Component: Ion scavenger G-1: IXEPLAS-A1 (Zr, Mg, Al-based ion scavenger, manufactured by Toagosei Co., Ltd., primary particle size 500 nm) G-2: IXEPLAS-A2 (Zr, Mg, Al-based ion scavenger, manufactured by Toagosei Co., Ltd., primary particle size 200 nm) G-3: IXEPLAS-A3 (surface-treated IXEPLAS-Al, manufactured by Toagosei Co., Ltd.) G-4: DHT-4A-2 (Mg, Al-based ion scavenger, manufactured by Kyowa Chemical Industry Co., Ltd.) The ion trapping agent used was finely pulverized to have a D95 of less than 5 μm.

[0153] <Preparation of First Adhesive Layer> The materials shown in Table 1 were mixed in the composition ratios shown in Table 1 (the values ​​in Table 1 indicate the non-volatile content), and then the compositions were coated on a release-treated PET (polyethylene terephthalate) film while applying a magnetic field. The organic solvent and other components were then dried with hot air at 70°C for 5 minutes to obtain composition layers each containing a composition containing each component. The composition layers were coated so that their thickness after drying would be 3 to 4 μm. The composition layers were then irradiated with light (UV irradiation: metal halide lamp, cumulative light intensity: 1800 to 2300 mJ / cm). 2 ), a first adhesive layer with dispersed conductive particles was prepared, the thickness of which was measured using a contact thickness meter.

[0154] If the thickness of the layer or adhesive layer made of the first adhesive composition is smaller than the thickness (diameter) of the conductive particles, measuring the layer thickness using a contact thickness meter will reflect the thickness of the conductive particles, and the thickness of the region where the conductive particles are present will be measured. Therefore, after producing a two-layer adhesive film in which the first adhesive layer and the second adhesive layer are laminated, the thickness of the first adhesive layer located in the space between adjacent conductive particles was measured using a scanning electron microscope according to the method described above (paragraph 0083).

[0155] [Table 1]

[0156] <Preparation of second adhesive layer> The materials shown in Table 2 were mixed in the composition ratios shown in Table 2 (the values ​​in Table 2 indicate the non-volatile content), and then a composition was obtained. This was then coated on a release-treated PET (polyethylene terephthalate) film, and the organic solvent and other components were dried with hot air at 70°C for 5 minutes to produce a second composition layer made of a composition containing each component. The composition layers were coated so that their thickness after drying would be 8 to 9 μm. The thickness was measured using a contact thickness meter.

[0157] [Table 2]

[0158] (Examples 1 to 4 and Comparative Examples 1 and 2) [Preparation of adhesive film] Using the first adhesive layer and second adhesive layer prepared above, adhesive films with the configurations shown in Table 3 were prepared. For example, in the adhesive film of Example 1, a first adhesive layer formed from composition P-1 was attached to a second adhesive layer formed from composition S-1 while applying a temperature of 50 to 60°C to obtain the adhesive film of Example 1. For the adhesive films of Examples 2 to 4 and Comparative Examples 1 and 2, adhesive films with the configurations shown in Table 3 were prepared in the same manner as in Example 1.

[0159] The projected particle density of the adhesive films obtained in Examples 1 to 4 and Comparative Examples 1 and 2 was measured, and all were found to be approximately 18,000 particles / mm 2 It was.

[0160] [Evaluation of circuit connection structures] <Fabrication of Circuit Connection Structure-1> The first circuit component was an IC chip (0.9 mm × 20.3 mm, thickness: 0.3 mm, bump electrode size: 70 μm × 12 μm, spacing between bump electrodes: 12 μm, bump electrode thickness: 9 μm) with two rows of staggered bump electrodes. The second circuit component was a polyimide substrate (manufactured by DuPont-Toray Co., Ltd., 200H) (38 mm × 28 mm, thickness: 0.05 mm) with a 50 nm Ti / 400 nm Al wiring pattern (pattern width: 17 μm, spacing between electrodes: 7 μm) formed on its surface.

[0161] Circuit connection structures were fabricated using the adhesive films of Examples 1 to 4 and Comparative Examples 1 and 2. The adhesive film was cut to a width of 2.0 mm, and the adhesive film was placed on the first circuit member so that the first adhesive layer and the first circuit member were in contact. Using a thermocompression bonding device (BS-17U, manufactured by Ohashi Manufacturing Co., Ltd.) consisting of a stage made of a ceramic heater and a tool (8 mm x 50 mm), the adhesive film was pressed at 70°C and 0.98 MPa (10 kgf / cm 2 ) for 2 seconds to attach the adhesive film to the first circuit member, and then the release film on the side of the adhesive film opposite the first circuit member was peeled off. Next, after aligning the bump electrodes of the first circuit member with the wiring pattern of the second circuit member, an 8 mm x 45 mm heat tool was used, and heating and pressure were applied for 5 seconds under connection conditions of 170°C and an area-equivalent pressure of 30 MPa at the bump electrodes, with a 50 μm-thick Teflon (registered trademark) interposed between them as a buffer material, to attach the second adhesive layer of the adhesive film to the second circuit member, thereby producing circuit connection structures-1.

[0162] <Fabrication of Circuit Connection Structure-2> The first circuit component was an IC chip (0.9 mm × 20.3 mm, thickness: 0.3 mm, bump electrode size: 70 μm × 12 μm, spacing between bump electrodes: 12 μm, bump electrode thickness: 9 μm) with bump electrodes arranged in a staggered pattern in two rows. The second circuit component was a glass substrate (Corning, #1737, 38 mm × 28 mm, thickness: 0.05 mm) with an ITO wiring pattern (pattern width: 19 μm, spacing between electrodes: 5 μm) formed on its surface.

[0163] Circuit connection structures were fabricated using the adhesive films of Examples 1 to 4 and Comparative Examples 1 and 2. The adhesive film was cut to a width of 2.0 mm, and the adhesive film was placed on the first circuit member so that the first adhesive layer and the first circuit member were in contact. Using a thermocompression bonding device (BS-17U, manufactured by Ohashi Manufacturing Co., Ltd.) consisting of a stage made of a ceramic heater and a tool (8 mm x 50 mm), the adhesive film was pressed at 70°C and 0.98 MPa (10 kgf / cm 2 ) for 2 seconds to attach the adhesive film to the first circuit member, and then the release film on the side of the adhesive film opposite the first circuit member was peeled off. Next, after aligning the bump electrodes of the first circuit member with the wiring pattern of the second circuit member, an 8 mm x 45 mm heat tool was used, and heating and pressure were applied for 5 seconds under connection conditions of 170°C and an area-equivalent pressure of 30 MPa at the bump electrodes, with a 50 μm-thick Teflon (registered trademark) interposed between them as a buffer material, to attach the second adhesive layer of the adhesive film to the second circuit member, thereby producing circuit connection structures-2.

[0164] (Evaluation of connection resistance) The initial connection resistance (conduction resistance) of the fabricated circuit connection structure-1 was measured by the four-terminal method. A multimeter MLR21 manufactured by ETAC was used for the measurement. The potential difference was measured at 14 random points and the average value was calculated. The average potential difference was converted into a connection resistance value and evaluated according to the following criteria. The results are shown in Table 3. A: Connection resistance is less than 1.0 Ω B: Connection resistance is 1.0Ω or more

[0165] (Insulation resistance evaluation) After the fabricated circuit connection structure-2 was subjected to a high temperature and high humidity test (storage for 500 hours under conditions of a temperature of 85°C and a humidity of 85%RH), a voltage of 50V was applied to the wiring pattern, and the insulation resistance between the circuit electrodes at a total of 1,440 locations was measured all at once. This measurement was performed on 20 samples, and of all 20 samples, the insulation resistance value was 10 9 The number of samples with a resistance of Ω or more was counted. The insulation resistance was evaluated based on the number of samples obtained according to the following criteria. The results are shown in Table 3. A: 20 pieces have an insulation resistance of 10 9 Ω or more B: 19 to 17 pieces have an insulation resistance of 10 9 Ω or more C: 16 to 13 pieces have an insulation resistance of 10 9 Ω or more

[0166] [Table 3]

[0167] As shown in Table 3, the adhesive films of Examples 1 to 4, which contained the above-described cationically polymerizable compound, thermal cationic polymerization initiator, and ion scavenger, were both rated A for connection resistance and insulation resistance. On the other hand, the adhesive film of Comparative Example 1, which did not contain an ion scavenger, was rated A for connection resistance but C for insulation resistance. Furthermore, the adhesive film of Comparative Example 2, which did not contain an ion scavenger and had an increased amount of acrylate component, was rated B for insulation resistance, but was also rated B due to increased connection resistance. [Explanation of symbols]

[0168] 1...first adhesive layer, 2...second adhesive layer, 4...conductive particles, 5...adhesive component, 10...adhesive film for circuit connection (adhesive film), 11...first circuit board, 12...first electrode (circuit electrode), 13...first circuit member, 14...second circuit board, 15...second electrode (bump electrode), 16...second circuit member, 17...circuit connection portion.

Claims

1. An adhesive film for circuit connection containing conductive particles, the adhesive film includes, in a thickness direction of the film, a region A containing a cationically polymerizable compound, a thermal cationic polymerization initiator, and an ion scavenger; the region A includes, in the thickness direction of the film, a region P further containing a cured product of a photocurable resin component including a radical polymerizable compound and a photoradical polymerization initiator; The conductive particles are dispersed in the region P, the region A includes, in a thickness direction of the film, a region S containing the cationically polymerizable compound, the thermal cationic polymerization initiator, and the ion scavenger, but not containing a cured product of a photocurable resin component; the cationically polymerizable compound includes a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule, the thermal cationic polymerization initiator comprises an anilinium salt; An adhesive film for circuit connection, wherein the ion scavenger comprises at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide.

2. 2. The circuit connecting adhesive film according to claim 1, wherein the conductive particles have a palladium plating.

3. 3. The adhesive film for circuit connection according to claim 1, wherein the anilinium salt is an anilinium salt having an anion containing boron as a constituent element.

4. a first adhesive layer containing conductive particles, a cured product of a photocurable resin component, and a first thermosetting resin component; and a second adhesive layer provided on the first adhesive layer and containing a second thermosetting resin component; the photocurable resin component contains a radical polymerizable compound and a photoradical polymerization initiator, one or both of the first adhesive layer and the second adhesive layer further contains an ion scavenger; one or both of the first thermosetting resin component and the second thermosetting resin component contain a cationic polymerizable compound and a thermal cationic polymerization initiator; the cationically polymerizable compound includes a compound having one or more ring-opening polymerizable cyclic ether groups in the molecule, the thermal cationic polymerization initiator comprises an anilinium salt; An adhesive film for circuit connection, wherein the ion scavenger comprises at least one metal compound selected from the group consisting of aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, zirconium hydroxide, zirconium oxide, bismuth hydroxide, bismuth oxide, calcium hydroxide, calcium oxide, tin hydroxide, tin oxide, manganese hydroxide, manganese oxide, antimony hydroxide, antimony oxide, silicon hydroxide, silicon oxide, titanium hydroxide, and titanium oxide.

5. 5. The adhesive film for circuit connection according to claim 4, wherein the conductive particles have a palladium plating.

6. 6. The adhesive film for circuit connection according to claim 4, wherein the anilinium salt is an anilinium salt having an anion containing boron as a constituent element.

7. 10. A method for manufacturing a circuit connection structure, comprising the steps of: interposing an adhesive film for circuit connection according to any one of claims 1 to 6 between a first circuit member having a first electrode and a second circuit member having a second electrode; and thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other.

8. 8. The method for manufacturing a circuit connection structure according to claim 7, wherein one of the first circuit member and the second circuit member is an IC chip, and the other is a plastic substrate having an electrode containing Ti.

9. preparing the adhesive film for circuit connection; laminating the circuit connecting adhesive film onto the first circuit member; 9. The method for manufacturing a circuit connection structure according to claim 7, further comprising a step of: placing the second circuit member on the first circuit member laminated with the adhesive film for circuit connection, thereby interposing the adhesive film for circuit connection between the first circuit member and the second circuit member.

10. a first circuit member having a first electrode; a second circuit member having a second electrode; a circuit connection portion disposed between the first circuit member and the second circuit member, electrically connecting the first electrode and the second electrode to each other; Equipped with A circuit connection structure, wherein the circuit connection portion comprises a cured product of the adhesive film for circuit connection according to any one of claims 1 to 6.

11. 11. The circuit connection structure according to claim 10, wherein one of the first circuit member and the second circuit member is an IC chip, and the other is a plastic substrate having an electrode containing Ti.

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