Adhesive film for circuit connection and method for manufacturing the same, and circuit connection structure and method for manufacturing the same

Abstract

Disclosed is a circuit-connection adhesive film. The circuit-connection adhesive film comprises: a first adhesive layer that contains electroconductive particles, a cured product from a curable resin component, and a first thermosetting resin component; and a second adhesive layer that is provided on the first adhesive layer and contains a second thermosetting resin component. When the first adhesive layer of the circuit-connection adhesive film is bonded by treatment using conditions of a temperature of 60°C, an areawise pressure for the first adhesive layer of 1 MPa, and a time of 1 second to a glass substrate that has indium tin oxide (ITO) wiring, the post-bonding peel strength at 40°C between the glass substrate and the first adhesive layer is 20-60 N / m.

Description

[Technical Field]

[0001] This disclosure relates to an adhesive film for circuit connections, a circuit connection structure, and a method for manufacturing the same. [Background technology]

[0002] Conventionally, anisotropic conductive films, in which conductive particles are dispersed in an adhesive film, have been used for connections such as between liquid crystal displays and tape carrier packages (TCPs), between flexible printed circuit boards (FPCs) and TCPs, or between FPCs and printed wiring boards. Specifically, a circuit connection structure can be obtained by bonding circuit components together through circuit connection portions formed by the circuit connection adhesive film, and by electrically connecting electrodes on the circuit components via the conductive particles in the circuit connection portions. Furthermore, when mounting semiconductor silicon chips onto substrates, so-called chip-on-glass (COG) mounting, in which semiconductor silicon chips are directly mounted onto the substrate, has been adopted as an alternative to conventional wire bonding, and anisotropic conductive films are also used in COG mounting.

[0003] In the field of precision electronic equipment, where anisotropically conductive adhesive films for circuit connections are used, the density of circuits is increasing, and the spacing between electrodes is becoming extremely narrow, for example, 15 μm or less. Furthermore, the bump electrodes of the connecting components are also becoming smaller in area. In order to obtain a stable electrical connection with such small-area electrodes, a sufficient number of conductive particles must be interposed between the bump electrode and the circuit electrode on the substrate side.

[0004] In contrast, for example, Patent Document 1 proposes a method in which conductive particles are unevenly distributed on one side of an anisotropic conductive adhesive sheet, thereby separating the conductive particles from each other. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2005 / 054388 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in the method described in Patent Document 1, conductive particles may flow out from between opposing electrode circuits when the circuits are connected, and there is still room for improvement in terms of the capture rate of conductive particles.

[0007] On the other hand, for example, curing the adhesive in the adhesive film for circuit connections with heat or light is being considered to suppress the fluidity of conductive particles and improve the capture rate of conductive particles. However, in this case, the exclaveability of the resin in the adhesive will also decrease, which is expected to increase the connection resistance.

[0008] Therefore, the main objective of this disclosure is to provide an adhesive film for circuit connections that can improve the capture rate of conductive particles between opposing electrodes of a circuit connection structure and reduce connection resistance. [Means for solving the problem]

[0009] One aspect of this disclosure relates to an adhesive film for circuit connections. The adhesive film for circuit connections comprises a first adhesive layer containing conductive particles, a cured product of a curable 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. When the first adhesive layer of the adhesive film for circuit connections is applied to a glass substrate having indium tin oxide (ITO) wiring by processing it at a temperature of 60°C, an area-equivalent pressure of 1 MPa for the first adhesive layer, and a time of 1 second, the peel strength between the glass substrate and the first adhesive layer at 40°C after application is 20 to 60 N / m. When the peel strength is 60 N / m or less, the hardness of the resin is sufficient in terms of resin fluidity, so the fluidity of the resin during mounting is reduced, and as a result, the capture rate of conductive particles can be improved. On the other hand, if the peel strength exceeds 60 N / m, the hardness of the resin is too soft from the viewpoint of resin fluidity, resulting in high resin fluidity during mounting and a tendency for insufficient capture of conductive particles. If the peel strength is 20 N / m or higher, the hardness of the resin is sufficient from the viewpoint of resin fluidity, resulting in sufficient removal of the resin from the adhesive during mounting, and as a result, it is possible to reduce connection resistance. On the other hand, if the peel strength is less than 20 N / m, the hardness of the resin is too hard from the viewpoint of resin fluidity, resulting in insufficient removal of the resin from the adhesive during mounting, and a tendency for connection resistance to increase. Furthermore, if the peel strength is 20 N / m or higher, preferably 20 to 60 N / m, it is possible to obtain excellent transferability to glass substrates and sufficient indentation strength in circuit connection structures.

[0010] In one embodiment of the adhesive film for circuit connections, the curable resin component is photocurable. In another embodiment of the adhesive film for circuit connections, the curable resin component is thermocurable.

[0011] The thickness of the first adhesive layer may be 5 μm or less. By having a thickness of 5 μm or less for the first adhesive layer, conductive particles can be captured more efficiently during circuit connection.

[0012] Another aspect of this disclosure relates to a method for manufacturing an adhesive film for circuit connections. The method for manufacturing the adhesive film for circuit connections comprises the steps of: forming a first adhesive layer by curing a curable resin component on a layer made of a composition containing conductive particles, a curable resin component, and a first thermosetting resin component; and providing a second adhesive layer containing a second thermosetting resin component on the first adhesive layer to obtain an adhesive film for circuit connections. When the first adhesive layer of the adhesive film for circuit connections is applied to a glass substrate having indium tin oxide (ITO) wiring by processing it under the conditions of a temperature of 60°C, an area-equivalent pressure of 1 MPa for the first adhesive layer, and a time of 1 second, the peel strength between the glass substrate and the first adhesive layer at 40°C after application is 20 to 60 N / m. According to this method for manufacturing an adhesive film for circuit connections, it is possible to manufacture an adhesive film for circuit connections that can improve the capture rate of conductive particles between opposing electrodes of a circuit connection structure and reduce connection resistance.

[0013] Another aspect of this disclosure relates to a method for manufacturing a circuit connection structure. The method for manufacturing the circuit connection structure includes the steps of interposing the above-mentioned circuit connection adhesive film between a first circuit member having a first electrode and a second circuit member having a second electrode, and then heat-pressing the first circuit member and the second circuit member together to electrically connect the first electrode and the second electrode.

[0014] Another aspect of this disclosure relates to a circuit connection structure. The circuit connection structure comprises 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. The circuit connection portion includes a cured product of the above-mentioned circuit connection adhesive film. [Effects of the Invention]

[0015] According to the present disclosure, there is disclosed an adhesive film for circuit connection capable of improving the capture rate of conductive particles between opposing electrodes of a circuit connection structure and reducing the connection resistance. The adhesive films for circuit connection according to some embodiments are excellent in transferability to a glass substrate and can obtain sufficient indentation strength in a circuit connection structure. Further, according to the present disclosure, there is disclosed a method for manufacturing such an adhesive film for circuit connection. Furthermore, according to the present disclosure, there are disclosed a circuit connection structure using such an adhesive film for circuit connection and a method for manufacturing the same.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an embodiment of an adhesive film for circuit connection. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an embodiment of a circuit connection structure. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an embodiment of a method for manufacturing a circuit connection structure. FIGS. 3(a) and 3(b) are schematic cross-sectional views showing each step. [Figure 4] FIG. 4 is a schematic top view showing a laminate in the peel strength measurement of an example.

Embodiments for Carrying Out the Invention

[0017] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the following description, the same or corresponding parts will be denoted by the same reference numerals, and redundant descriptions will be omitted. However, this disclosure is not limited to the embodiments described below. In this specification, (meth)acryloyl group means acryloyl group or methacryloyl group, and the same applies to other similar expressions such as (meth)acrylate. In this specification, numerical ranges indicated using "~" indicate a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. The lower and upper limits of numerical ranges described in this specification can be arbitrarily combined with the lower or upper limits of other numerical ranges. In numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. In addition, the upper and lower limits described individually can be arbitrarily combined. In the notation of numerical range "A~B", the numbers A and B at both ends are included in the numerical range as the lower and upper limits, respectively. In this specification, for example, the phrase "10 or more" means "10" and "a number greater than 10," and the same applies when the numbers are different. Similarly, for example, the phrase "10 or less" means "10" and "a number less than 10," and the same applies when the numbers are different. Unless otherwise specified, each component and material exemplified in this specification may be used alone or in combination of two or more. The content of each component in a composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component, unless otherwise specified.

[0018] [Adhesive film for circuit connections] Figure 1 is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connections. The adhesive film 10 for circuit connections shown in Figure 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 curable 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.

[0019] The adhesive film 10 has conductive particles 4 dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 may be an anisotropically conductive adhesive film for circuit connection (anisotropically conductive adhesive film). The adhesive film 10 may be interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and used to electrically connect the first electrode and the second electrode to each other by thermocompression bonding the first and second circuit members.

[0020] <First adhesive layer> The first adhesive layer 1 contains conductive particles 4 (hereinafter sometimes referred to as "component (A)"), a cured product of a curable resin component (hereinafter sometimes referred to as "component (B)"), and a (first) thermosetting resin component (hereinafter sometimes referred to as "component (C)"). The first adhesive layer 1 can be obtained, for example, by polymerizing the components contained in component (B) and curing component (B) by light, heat, moisture, etc., on a composition layer consisting of a composition containing component (A), component (B), and component (C). The first adhesive layer 1 contains component (A), an adhesive component 5 containing a cured product of component (B) and component (C). The cured product of component (B) may be a cured product in which component (B) has been completely cured, or a cured product in which a part of component (B) has been cured. Component (C) is a component that can flow when a circuit is connected, and is, for example, an uncured curable resin component.

[0021] (A) Component: Conductive particles Component (A) is not particularly limited as long as it is a conductive particle, and may be metal particles composed of metals such as Au, Ag, Pd, Ni, Cu, or solder, or conductive carbon particles composed of conductive carbon. Component (A) may also be a coated conductive particle comprising a core containing non-conductive glass, ceramic, or plastic (such as polystyrene), and a coating layer containing the above-mentioned metal or conductive carbon that covers the core. Among these, component (A) is preferably a coated conductive particle comprising a core containing metal particles or plastic formed from a heat-meltable metal, and a coating layer containing metal or conductive carbon that covers the core. Since such coated conductive particles can be easily deformed by heating or pressurizing the cured product of the thermosetting resin component, the contact area between the electrodes and component (A) can be increased when electrically connecting electrodes, thereby further improving conductivity between electrodes.

[0022] Component (A) may be insulating coated conductive particles comprising the above-mentioned metal particles, conductive carbon particles, or coated conductive particles, and an insulating layer that covers the surface of the particles and contains an insulating material such as resin. When component (A) is insulating coated conductive particles, even if the content of component (A) is high, the presence of an insulating layer on the surface of the particles can suppress the occurrence of short circuits due to contact between components (A) and can also improve the insulation between adjacent electrode circuits. Component (A) may be one of the above-mentioned conductive particles used alone or in combination of two or more types.

[0023] (A) 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 any 300 conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the largest value obtained is taken as the maximum particle size of component (A). If component (A) has protrusions or is not spherical, the particle size of component (A) is taken as the diameter of the circle circumscribing the conductive particle in the SEM image.

[0024] The average particle size of component (A) may be 1.0 μm or larger, 2.0 μm or larger, or 2.5 μm or larger, from the viewpoint of excellent dispersibility and conductivity. The average particle size of component (A) may be 20 μm or smaller, 10 μm or smaller, or 5 μm or smaller, from the viewpoint of excellent dispersibility and conductivity. In this specification, the particle size of any 300 conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the average value of the obtained particle sizes is defined as the average particle size.

[0025] In the first adhesive layer 1, it is preferable that component (A) is uniformly dispersed. From the viewpoint of obtaining stable connection resistance, the particle density of component (A) in the adhesive film 10 should be 100 particles / mm². 2 More than 1000 pieces / mm 2 More than 3000 pieces / mm 2 or more, or 5000 pieces / mm 2 The above is acceptable. The particle density of component (A) in the adhesive film 10 is 100,000 particles / mm² from the viewpoint of improving the insulation between adjacent electrodes. 2 Below, 70000 pieces / mm 2 Below, 50000 pieces / mm 2 The following, or 30,000 pieces / mm 2 The following is acceptable:

[0026] (A) The content of component (A) may be 1% by mass or more, 10% by mass or more, or 20% by mass or more, based on the total mass of the first adhesive layer, from the viewpoint of further improving conductivity. (A) The content of component (A) may be 80% by mass or less, 60% by mass or less, or 50% 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 this disclosure 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.

[0027] (B) Component: Curable resin component Component (B) may include a photocurable resin component (photocurable resin component), a thermosetting resin component (thermosetting resin component), a moisture-curable resin component (moisture-curable resin component), etc. Here, the thermosetting resin component may differ from component (C) described later in terms of curing system (e.g., radical curing system, cationic curing system, etc.), polymerization initiation temperature, etc. The polymerization initiation temperature can be adjusted by the type of polymerization initiator, etc. The thermosetting resin component of component (B) may have a lower polymerization initiation temperature than the thermosetting resin component of component (C). Component (B) may be a photocurable resin component or a thermosetting resin component, and is more preferably a photocurable resin component. Component (B) may be a combination of a polymerizable compound (hereinafter sometimes referred to as "MA component") and a polymerization initiator (hereinafter sometimes referred to as "MB component").

[0028] The photocurable resin component may be a radical-curable resin component or a cationic-curable resin component. The radical-curable resin component in the photocurable resin component may be, for example, a combination of a radical polymerizable compound (hereinafter sometimes referred to as "(MA-R) component") and a photoradical polymerization initiator (hereinafter sometimes referred to as "(MB-RL) component"). The cationic-curable resin component in the photocurable resin component may be, for example, a combination of a cationic polymerizable compound (hereinafter sometimes referred to as "(MA-C) component") and a photocationic polymerization initiator (hereinafter sometimes referred to as "(MB-CL) component").

[0029] The thermosetting resin component may be a radical-curable resin component or a cationic-curable resin component. The radical-curable resin component in the thermosetting resin component may be, for example, a combination of (MA-R) component and a thermal radical polymerization initiator (hereinafter sometimes referred to as "(MB-RH) component"). The cationic-curable resin component in the thermosetting resin component may be, for example, a combination of (MA-C) component and a thermal cationic polymerization initiator (hereinafter sometimes referred to as "(MB-CH) component").

[0030] It is preferable that component (B) and component (C) described below have different curing systems (e.g., radical curing system, cationic curing system, etc.). By having different curing systems for component (B) and component (C), it becomes possible to selectively and efficiently cure only component (B). More specifically, when a thermosetting resin component having cationic curability (e.g., a combination of (MA-C) and (MB-CH) components) is used as component (C), component (B) may be a photocurable resin component having radical curability (e.g., a combination of (MA-R) and (MB-RL) components) or a thermosetting resin component having radical curability (e.g., a combination of (MA-R) and (MB-RH) components), and more preferably a photocurable resin component having radical curability. When a radical-curable thermosetting resin component (for example, a combination of (MA-R) and (MB-RH) components) is used as component (C), component (B) may be a cationic-curable photocurable resin component (for example, a combination of (MA-C) and (MB-CL) components) or a cationic-curable thermosetting resin component (for example, a combination of (MA-C) and (MB-CH) components), and more preferably a cationic-curable photocurable resin component.

[0031] (MA-R) component: radical polymerizable compound The (MA-R) component is a compound that polymerizes by radicals generated from radical polymerization initiators (such as the (MB-RL) component and the (MB-RH) component). The (MA-R) component may be a monomer, or a polymer (or oligomer) formed by the polymerization of one or more monomers. The (MA-R) component may be used alone or in combination of multiple components.

[0032] The (MA-R) component is a compound having radical polymerizable groups that react with radicals. Examples of radical polymerizable groups include (meth)acryloyl groups, vinyl groups, allyl groups, styryl groups, alkenyl groups, alkenylene groups, maleimide groups, etc. The number of radical polymerizable groups (number of functional groups) in the (MA-R) component may be 2 or more from the viewpoint of easily obtaining the 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 curing shrinkage during polymerization. Furthermore, in order to balance the crosslinking density and curing shrinkage, in addition to compounds with a number of radical polymerizable groups within the above range, compounds with a number of radical polymerizable groups outside the above range may also be used.

[0033] The (MA-R) component may, for example, contain a polyfunctional (two- or more functional) (meth)acrylate from the viewpoint of suppressing the flow of conductive particles. The polyfunctional (two- or more functional) (meth)acrylate may be a bifunctional (meth)acrylate, and the bifunctional (meth)acrylate may be a bifunctional aromatic (meth)acrylate.

[0034] 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, Meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, 1,3-butanediol 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, ethoxylated 2-methyl-1,3-propanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate Aliphatic (meth)acrylates such as 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, ditrimethylolpropanetetraacrylate, and dipentaerythritol hexa(meth)acrylate;Aromatic (meth)acrylates such as ethoxylated bisphenol A type di(meth)acrylate, propoxylated bisphenol A type di(meth)acrylate, ethoxylated propoxylated bisphenol A type di(meth)acrylate, ethoxylated bisphenol F type di(meth)acrylate, propoxylated bisphenol F type di(meth)acrylate, ethoxylated propoxylated bisphenol F type di(meth)acrylate, ethoxylated fluorene type di(meth)acrylate, propoxylated fluorene type di(meth)acrylate, and ethoxylated propoxylated fluorene type di(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.

[0035] The content of polyfunctional (two or more functional) (meth)acrylate may be, for example, 40-100% by mass, 50-100% by mass, or 60-100% by mass, based on the total mass of the (MA-R) component, from the viewpoint of achieving both a reduction in connection resistance and suppression of particle flow.

[0036] The (MA-R) component may further contain monofunctional (meth)acrylates in addition to polyfunctional (bifunctional or more) (meth)acrylates. Examples of monofunctional (meth)acrylates 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, 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)acryloyl Aliphatic (meth)acrylates such as methyl 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, phenoxymethyl Aromatic (meth)acrylates such as ethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, phenoxypolypropylene 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 include (meth)acrylates having epoxy groups such as glycidyl (meth)acrylate, (meth)acrylates having alicyclic epoxy groups such as 3,4-epoxycyclohexylmethyl (meth)acrylate, and (meth)acrylates having oxetanyl groups such as (3-ethyloxetan-3-yl)methyl (meth)acrylate.

[0037] The content of monofunctional (meth)acrylate may be, for example, 0-60% by mass, 0-50% by mass, or 0-40% by mass, based on the total mass of the (MA-R) component.

[0038] The cured product of component (B) may have polymerizable groups that react with a factor other than a radical. The polymerizable groups that react with a factor other than a radical may be cationic polymerizable groups that react with a cation. Examples of cationic polymerizable groups include epoxy groups such as glycidyl groups, alicyclic epoxy groups such as epoxycyclohexylmethyl groups, and oxetanyl groups such as ethyloxetanylmethyl groups. The cured product of component (B) having polymerizable groups that react with a factor other than a radical can be introduced by using a (meth)acrylate having polymerizable groups that react with a factor other than a radical, such as an epoxy group (meth)acrylate, an alicyclic epoxy group (meth)acrylate, or an oxetanyl group (meth)acrylate, as component (B). The mass ratio of (meth)acrylate having polymerizable groups reacting by means other than radicals to the total mass of (MA-R) components (mass of (meth)acrylate having polymerizable groups reacting by means other than radicals (amount charged) / total mass of (MA-R) components (amount charged)) may be, for example, 0 to 0.7, 0 to 0.5, or 0 to 0.3 from the viewpoint of improving reliability.

[0039] The (MA-R) component may contain polyfunctional (two or more functional) and monofunctional (meth)acrylates, as well as other radical polymerizable compounds. Examples of other radical polymerizable compounds include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, nadiimide derivatives, and the like. The content of the other radical polymerizable compounds may be, for example, 0 to 40% by mass, based on the total mass of the (MA-R) component.

[0040] (MB-RL) component: Photoradical polymerization initiator The (MB-RL) component is a polymerization initiator that generates radicals upon irradiation with light containing wavelengths in the range of 150 to 750 nm, preferably light containing wavelengths in the range of 254 to 405 nm, and more preferably light containing a wavelength of 365 nm (e.g., ultraviolet light). The (MB-RL) component may be used alone or in combination of multiple components.

[0041] The (MB-RL) component decomposes upon exposure to light, generating free radicals. In other words, the (MB-RL) component is a compound that generates radicals upon application of external light energy. The (MB-RL) component may be a compound having structures such as 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 benzyldimethyl ketal structure, or an α-hydroxyalkylphenone structure. The (MB-RL) component may be used alone or in combination of multiple components. From the viewpoint of easily obtaining the desired melt viscosity and being superior in reducing connection resistance, the (MB-RL) component 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.

[0042] 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)], etanone,1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(o-acetyloxime), and others.

[0043] Specific examples of compounds having an α-aminoalkylphenone structure include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1-morpholinophenyl)-butanone-1.

[0044] Specific examples of compounds having an acylphosphine oxide structure include bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide.

[0045] The content of the (MB-RL) 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 (MA-R) component, from the viewpoint of suppressing the flow of conductive particles.

[0046] (MB-RH) component: Thermal radical polymerization initiator The (MB-RH) component is a polymerization initiator that generates radicals upon heat. The half-life temperature of the (MB-RH) component may be, for example, 50 to 100°C. The (MB-RH) component may be used alone or in combination of multiple components.

[0047] (MB-RH) components include, for example, diacyl peroxides such as octanoyl peroxide, lauroyl peroxide, stearyl peroxide, and benzoyl peroxide; t-butyl peroxypivalate, t-hexyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis(2-ethylhexanoyl peroxy)hexane, t-hexyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, t-hexyl peroxyisopropyl monocarbonate, and t-butyl peroxyisopropyl monocarbonate. Examples include peroxyesters such as oxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurylate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, and t-butyl peroxyacetate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2'-dimethylvaleronitrile).

[0048] The content of the (MB-RH) component may be, for example, 0.1 to 15 parts by mass, 0.3 to 12 parts by mass, or 0.5 to 10 parts by mass per 100 parts by mass of the (MA-R) component, from the viewpoint of suppressing the flow of conductive particles.

[0049] (MA-C) component: Cationic polymerizable compound The (MA-C) component is a compound that crosslinks by reacting with a cationic polymerization initiator (such as the (MB-CL) component or the (MB-CH) component). Note that the (MA-C) component means a compound that does not have a radical polymerizable group that reacts with radicals, and the (MA-C) component is not included in the (MA-R) component. Examples of the (MA-C) component include epoxy compounds, oxetane compounds, and alicyclic epoxy compounds. From the viewpoint of further improving the effect of reducing connection resistance and providing superior connection reliability, the (MA-C) component may contain at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds, for example, and may contain an alicyclic epoxy compound. The (MA-C) component may be used alone or in combination of multiple types.

[0050] Examples of epoxy compounds include bisphenol-type epoxy resins derived from epichlorohydrin and bisphenol compounds such as bisphenol A, bisphenol F, or bisphenol AD; epoxy novolac resins derived from epichlorohydrin and novolac resins such as phenol novolac or cresol novolac; and various epoxy compounds having two or more glycidyl groups in one molecule, such as glycidylamines, glycidyl ethers, biphenyls, and alicyclic compounds. These compounds may be used individually or in combination.

[0051] The oxetane compound can be used without particular limitations as long as it has an oxetanyl group and does not have a radical polymerizable group. Examples of 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 may be used individually or in combination.

[0052] The alicyclic epoxy compound can be used without particular limitation as long as it has an alicyclic epoxy group (e.g., epoxycyclohexyl group) and does not have a radical polymerizable group. Examples of commercially available alicyclic epoxy compounds include CEL8010, CEL2021P, CEL2081 (trade names, manufactured by Daicel Corporation), and the like. These may be used alone or in combination of two or more.

[0053] (MB-C-L) component: Photo cationic polymerization initiator (MB-C-L) component is a polymerization initiator that generates a substance capable of initiating cationic polymerization upon irradiation with light having a wavelength within the range of 150 to 750 nm, preferably light having a wavelength within the range of 254 to 405 nm, and more preferably light having a wavelength of 365 nm (e.g., ultraviolet light). Note that the (MB-C-L) component may also act as the (MB-C-H) component described later.

[0054] (MB-C-L) 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 thereof include onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, and anilinium salts having anions such as these. These may be used alone or in combination of two or more.

[0055] (MB-C-L) component commercially available products include, for example, CPI-100P, CPI-110P, CPI-101A, CPI-200K, CPI-210S (all manufactured by San-Apro Ltd.), UVI-6990, UVI-6992, UVI-6976 (all manufactured by Dow Chemical Japan Ltd.), SP-150, SP-152, SP-170, SP-172, SP-300 (all manufactured by ADEKA Corporation), and the like.

[0056] The content of component (MB-CL) may be, for example, 0.1 to 15 parts by mass, 0.3 to 12 parts by mass, 0.5 to 10 parts by mass, or 1 to 5 parts by mass per 100 parts by mass of component (MA-C), from the viewpoint of ensuring the formability and curability of the adhesive film for forming the first adhesive layer.

[0057] (MB-CH) component: Thermal cationic polymerization initiator The (MB-CH) component is a polymerization initiator that generates a substance that initiates cationic polymerization upon heat (e.g., 40-150°C). Note that the (MB-CH) component may also act as the (MB-CL) component mentioned above.

[0058] The (MB-CH) component, like the (MB-CL) component, 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 include onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, and anilinium salts, which have anions such as those mentioned above. These may be used individually or in combination.

[0059] Examples of commercially available products containing the (MB-CH) component include CP-66, CP-77 (both manufactured by ADEKA Corporation), SI-25, SI-45, SI-60, SI-60L, SI-60LA, SI-60B, SI-80L, SI-100L, SI-110L, SI-180L (all manufactured by Sanshin Chemical Industry Co., Ltd.), CI-2855 (manufactured by Nippon Soda Co., Ltd.), and PI-2074 (manufactured by Rhodia Japan Co., Ltd.).

[0060] The content of component (MB-CH) may be, for example, 0.1 to 50 parts by mass, 1 to 45 parts by mass, 10 to 40 parts by mass, or 20 to 35 parts by mass per 100 parts by mass of component (MA-C), from the viewpoint of ensuring the formability and curability of the adhesive film for forming the first adhesive layer.

[0061] The content of cured product of component (B) (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 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 exhibiting low resistance in low-pressure mounting. When the content of cured product of component (B) is within the above range, the effects of this disclosure 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.

[0062] (C) Component: Thermosetting resin component Component (C) is not particularly limited as long as it is a thermosetting curable resin component, but it may be the radical curable resin component described above (a combination of (MA-R) component and (MB-RH) component), or the cationic curable resin component described above (a combination of (MA-C) component and (MB-CH) component). Component (C) may be a cationic curable resin component (a combination of (MA-C) component and (MB-CH) component).

[0063] Since the (MA-R), (MB-RH), (MA-C), and (MB-CH) components used in component (C) are the same as those used in component (B), a detailed explanation is omitted here. Furthermore, the content of (MB-RH) component relative to (MA-R) component and the content of (MB-CH) component relative to (MA-C) component in component (C) may be within the same range as in the case of component (B).

[0064] 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 content of the components contained in the first thermosetting resin component and the second thermosetting resin component (e.g., (MA-R) component, (MB-RH) component, (MA-C) component, (MB-CH) component, etc.) may be the same or different.

[0065] The content of component (C) may be 3% by mass or more, 5% by mass or more, 10% by mass or more, or 15% 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 formation of the adhesive film for forming the first adhesive layer. When the content of component (C) is within the above ranges, the effects of this disclosure 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 ranges.

[0066] [Other ingredients] The first adhesive layer 1 may further contain other components in addition to component (A), the cured product of component (B), and component (C). Examples of other components include thermoplastic resin (hereinafter sometimes referred to as "component (D)"), filler (hereinafter sometimes referred to as "component (E)"), coupling agent (hereinafter sometimes referred to as "component (F)"), and the like.

[0067] Examples of component (D) include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylic rubber, epoxy resin (solid at 25°C), etc. These may be used individually or in combination. By further containing component (D) in a composition containing components (A), (B), and (C), a composition layer (and further, the first adhesive layer 1) can be easily formed from the composition. Among these, component (D) may be, for example, phenoxy resin.

[0068] The content of component (D) may be 1% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total mass of the first adhesive layer, and may be 60% by mass or less, 50% by mass or less, 40% by mass or less, or 30% by mass or less. 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.

[0069] Component (E) may be, for example, a non-conductive filler (e.g., non-conductive particles). Component (E) may be either an inorganic filler or an organic filler. Examples of inorganic fillers include metal oxide nanoparticles such as silica nanoparticles, alumina nanoparticles, silica-alumina nanoparticles, titania nanoparticles, and zirconia nanoparticles; and inorganic nanoparticles such as metal nitride nanoparticles. Examples of organic fillers include organic nanoparticles such as silicone nanoparticles, methacrylate-butadiene-styrene nanoparticles, acrylic-silicone nanoparticles, polyamide nanoparticles, and polyimide nanoparticles. These may be used individually or in combination. Component (E) may be, for example, silica nanoparticles. The content of component (E) may be 0.1 to 10% by mass based on the total mass of the first adhesive layer. The content of component (E) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the range described above.

[0070] Examples of component (F) include silane coupling agents having organic functional groups such as (meth)acryloyl groups, mercapto groups, amino groups, imidazole groups, and epoxy groups; silane compounds such as tetraalkoxysilanes; tetraalkoxytitanate derivatives; and polydialkyltitanate derivatives. These may be used individually or in combination. The adhesion of the first adhesive layer 1 can be further improved by containing component (F). Component (F) may be, for example, a silane coupling agent. The content of component (F) may be 0.1 to 10% by mass based on the total mass of the first adhesive layer. The content of component (F) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the range described above.

[0071] [Other additives] The first adhesive layer 1 may further contain other additives such as softeners, accelerators, degradation inhibitors, colorants, flame retardants, and thixotropic agents. The content of these other additives may be, for example, 0.1 to 10% by mass based on the total mass of the first adhesive layer. The content of 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 range described above.

[0072] 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 also be 4.5 μm or less or 4.0 μm or less. By having a thickness d1 of 5 μm or less of the first adhesive layer 1, 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: about 1 mm), casting a resin composition consisting of 100 g of bisphenol A type epoxy resin (product name: JER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a hardener (product name: Epomount hardener, manufactured by Refinetech Co., Ltd.), performing cross-sectional polishing using a polishing machine, and measuring using a scanning electron microscope (SEM, product name: SU-8000, manufactured by Hitachi High-Tech Science Corporation). Furthermore, as shown in Figure 1, if 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 to the second adhesive layer 2 to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 located in the spaced portion between adjacent conductive particles 4,4 (the distance shown as d1 in Figure 1) is the thickness of the first adhesive layer 1, and the exposed portion of the conductive particles 4 is not included in the thickness of the first adhesive layer 1. The length of the exposed portion of the conductive particles 4 may be, for example, 0.1 μm or more, or 5 μm or less.

[0073] <Second adhesive layer> The second adhesive layer 2 contains component (C). The (MA-R), (MB-RH), (MA-C), and (MB-CH) components used in component (C) in the second adhesive layer 2 (i.e., the second thermosetting resin component) are the same as the (MA-R), (MB-RH), (MA-C), and (MB-CH) components used in component (C) in the first adhesive layer 1 (i.e., the first thermosetting resin component), so a detailed explanation is omitted here. The second thermosetting resin component may be the same as or different from the first thermosetting resin component. The second thermosetting resin component may be a combination of component (MA-C) and component (MB-CH).

[0074] (C) 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. (C) 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 leakage defects in reels, which is one form of supply.

[0075] The second adhesive layer 2 may further contain other components and other additives of the first adhesive layer 1. Preferred embodiments of the other components and other additives are the same as those of the preferred embodiments of the first adhesive layer 1.

[0076] 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.

[0077] The content of component (E) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, and may be 70% by mass or less, 60% by mass or less, or 50% by mass or less, based on the total mass of the second adhesive layer.

[0078] The content of component (F) may be 0.1 to 10% by mass, based on the total mass of the second adhesive layer.

[0079] The content of other additives may be, for example, 0.1 to 10% by mass, based on the total mass of the second adhesive layer.

[0080] The thickness d2 of the second adhesive layer 2 may be set appropriately according to the height of the electrodes of the circuit members to be bonded. The thickness d2 of the second adhesive layer 2 may be 5 μm or more, 7 μm or more, 20 μm or less, or 15 μm or less, from the viewpoint of being able to sufficiently fill the space between electrodes and seal the electrodes and obtain better connection reliability. The thickness d2 of the second adhesive layer 2 can be determined, for example, by the same method as the measurement method for the thickness d1 of the first adhesive layer 1. Furthermore, if a part of the conductive particles 4 is exposed from the surface of the first adhesive layer 1 (for example, protruding towards the second adhesive layer 2 side), the distance from the surface 3a of the second adhesive layer 2 opposite to the first adhesive layer 1 side to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 located in the separated portion of adjacent conductive particles 4, 4 (the distance shown as d2 in Figure 1) is the thickness of the second adhesive layer 2.

[0081] The thickness of the adhesive film 10 (the sum of the thicknesses of all the 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 30 μm or less or 20 μm or less.

[0082] When the first adhesive layer 1 of the adhesive film 10 is applied to a glass substrate having indium tin oxide (ITO) wiring by processing under the conditions of a temperature of 60°C, an area-converted pressure of 1 MPa for the first adhesive layer 1, and a time of 1 second, the peel strength between the glass substrate and the first adhesive layer 1 at 40°C after application is 20 to 60 N / m. This peel strength is measured at a peel angle of 90° and a peel speed of 50 mm / min. If the peel strength is 60 N / m or less, the hardness of the resin is sufficient in terms of resin fluidity, resulting in less resin fluidity during mounting, and consequently, an improved capture rate of conductive particles. On the other hand, if the peel strength exceeds 60 N / m, the hardness of the resin is too soft in terms of resin fluidity, resulting in high resin fluidity during mounting, and a tendency for insufficient capture rate of conductive particles. When the peel strength is 20 N / m or higher, the hardness of the resin is sufficient from the viewpoint of resin fluidity, so the resin can be sufficiently removed from the adhesive during mounting, and as a result, connection resistance can be reduced. On the other hand, when the peel strength is less than 20 N / m, the hardness of the resin is too hard from the viewpoint of resin fluidity, so the resin cannot be sufficiently removed from the adhesive during mounting, and connection resistance tends to increase. Also, if the fluidity of the resin during mounting is high, conductive particles tend to stick together easily, and insulation tends to deteriorate. When the peel strength is 20 to 60 N / m, the fluidity of the resin during mounting is appropriate, and insulation tends to be good. Furthermore, when the peel strength is 20 N / m or higher, preferably 20 to 60 N / m, the transferability to the glass substrate is also excellent, and it is possible to obtain sufficient indentation strength in the circuit connection structure. The peel strength may be 25 N / m or more, 30 N / m or more, 35 N / m or more, or 40 N / m or more, and may also be 55 N / m or less or 50 N / m or less.

[0083] The peel strength can be determined, for example, by the following method. First, a glass substrate with ITO wiring is prepared (glass substrate size: 2.5 mm × 28 mm, glass substrate thickness: 300 μm, ITO wiring size: 2500 μm (2.5 mm) × 300 μm, ITO wiring thickness: 0.2 μm, number of ITO wirings: 28, space between ITO wirings: 300 μm). Next, an adhesive film is cut to 2 mm × 23 mm, and the first adhesive layer of the cut adhesive film is placed on the glass substrate with ITO wiring so as to be perpendicular to the ITO wiring. Then, the adhesive film is attached using a thermocompression press at a temperature of 60°C, an area-equivalent pressure of 1 MPa on the first adhesive layer, and a time of 1 second to obtain a laminate (see Figure 4). Next, the PET film of the second adhesive film (second adhesive layer) is peeled off, and a polyimide tape cut to 1.8 mm × 35 mm is attached to the second adhesive layer to obtain a sample for measurement. The glass substrate side of the measurement sample is placed on a hot plate set to 40°C, the tip of the polyimide tape is set in a tensile strength measuring device (Tensilon), and the glass substrate is fixed horizontally. Then, the peel strength at 40°C between the attached polyimide tape and the first adhesive layer 1 can be determined by pulling the tape at a peel angle of 90° and a peel speed of 50 mm / min.

[0084] The peel strength in the adhesive film 10 tends to vary depending on the first adhesive layer 1. The peel strength in the adhesive film 10 can be adjusted, for example, by adjusting the type and content of the constituent components contained in the first adhesive layer 1. More specifically, this can be done by changing the content of liquid components as components (B) and (C), changing the glass transition temperature (Tg) of component (D), changing the content of component (E), etc.

[0085] The flow rate of conductive particles in the adhesive film 10 may be, for example, 160% or more, 170% or more, or 180% or more, and may also be 250% or less, 230% or less, 220% or less, or 200% or less.

[0086] The flow rate of conductive particles can be determined by the following method. A sample is prepared by punching out the adhesive film 10 to a diameter of 1 mm using a trepanning device. The side of the punched sample with the first adhesive film (first adhesive layer) is heated and pressurized for 1 second under the conditions of a maximum temperature of 90°C and a film area equivalent pressure of 1 MPa, and attached to a cover glass. This is used as a test specimen (test specimen before pressing) for measuring the area of ​​the first adhesive layer before pressing. Next, the PET film on the second adhesive film (second adhesive layer) side is peeled off and a cover glass is placed on top. Then, the second adhesive film (second adhesive layer) and the cover glass are attached by heating and pressurizing for 5 seconds under the conditions of a maximum temperature of 170°C and a film area equivalent pressure of 80 MPa, and this is used as a test specimen (test specimen after pressing) for measuring the area of ​​the first adhesive layer after pressing. The area of ​​the first adhesive layer of the test specimen before pressing and the area of ​​the first adhesive layer of the test specimen after pressing are measured with a microscope, and the flow rate of conductive particles can be calculated from the following formula. Flow rate of conductive particles (%) = (Area of ​​the first adhesive layer on the test specimen after crimping / Area of ​​the first adhesive layer on the test specimen before crimping) × 100

[0087] The flow rate of conductive particles can be adjusted by controlling the type and content of the constituent components contained in the first adhesive layer 1. More specifically, by adjusting the curing rate of the first adhesive layer 1, a first adhesive layer having a flow rate of conductive particles within the above range can be obtained.

[0088] 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 and second circuit members.

[0089] The adhesive film 10 makes it possible to improve the capture rate of conductive particles between opposing electrodes of a circuit connection structure and to reduce connection resistance.

[0090] Although the adhesive film of this embodiment has been described above, this disclosure is not limited to the above embodiment.

[0091] The adhesive film may consist of two layers, for example, a first adhesive layer and a second adhesive layer, or it may consist of three or more layers, including the first adhesive layer and the 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 to the second adhesive layer.

[0092] The third adhesive layer contains component (C). Since the (MA-R), (MB-RH), (MA-C), and (MB-CH) components used in component (C) in the third adhesive layer (i.e., the third thermosetting resin component) are the same as the (MA-R), (MB-RH), (MA-C), and (MB-CH) components used in component (C) in the first adhesive layer 1 (i.e., the first thermosetting resin component), a detailed explanation is 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.

[0093] 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 providing 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 providing good half-cutability and blocking resistance (suppression of resin seepage from the reel).

[0094] The third adhesive layer may further contain other components and other additives of the first adhesive layer 1. Preferred embodiments of the other components and other additives are the same as those of the preferred embodiment of the first adhesive layer 1.

[0095] 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.

[0096] The content of component (E) may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, and 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 third adhesive layer.

[0097] The content of component (F) may be 0.1 to 10% by mass, based on the total mass of the third adhesive layer.

[0098] The content of other additives may be, for example, 0.1 to 10% by mass, based on the total mass of the third adhesive layer.

[0099] The thickness of the third adhesive layer may be set appropriately according to the minimum melt viscosity of the adhesive film, the height of the electrodes of the circuit components to be bonded, etc. Preferably, the thickness of the third adhesive layer is 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 sufficiently filling the space between electrodes and sealing the electrodes, thereby obtaining better connection reliability. The thickness of the third adhesive layer can be determined, for example, by the same method as the measurement method for the thickness d1 of the first adhesive layer 1.

[0100] Furthermore, although the circuit connection adhesive film in the above embodiment is an anisotropically conductive adhesive film having anisotropic conductivity, the circuit connection adhesive film may also be a conductive adhesive film that does not have anisotropic conductivity.

[0101] <Method for manufacturing adhesive film for circuit connections> A method for manufacturing an adhesive film for circuit connections according to one embodiment comprises, for example, a step (first step) of curing component (B) in a composition layer comprising a composition containing component (A), component (B), and component (C) (a first thermosetting resin component) to form a first adhesive layer, and a step (second step) of laminating a second adhesive layer containing component (C) (a second thermosetting resin component) on the first adhesive layer. The manufacturing method may further comprise a step (third step) of laminating a third adhesive layer containing component (C) (a third thermosetting resin component) on the layer of the first adhesive layer opposite to the second adhesive layer.

[0102] In the first step, for example, a composition containing components (A), (B), and (C), as well as other components and additives as needed, is dissolved or dispersed in an organic solvent by stirring, mixing, kneading, etc., to prepare a varnish composition. Then, the varnish composition is applied to a substrate that has been treated with a release agent using a knife coater, roll coater, applicator, comma coater, die coater, etc., and the organic solvent is evaporated by heating to form a composition layer on the substrate. At this time, the thickness of the final obtained first adhesive layer (first adhesive film) can be adjusted by adjusting the amount of varnish composition applied. Subsequently, component (B) in the composition layer is cured by light, heat, moisture, etc. (preferably light or heat, more preferably light) to form a first adhesive layer on the substrate. The first adhesive layer can be called the first adhesive film.

[0103] The organic solvent used in the preparation of the varnish composition is not particularly limited as long as it has the property of uniformly dissolving or dispersing each component. Examples of such organic solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, and butyl acetate. These organic solvents can be used individually or in combination of two or more. Stirring, mixing, or kneading during the preparation of the varnish composition can be carried out using, for example, a stirrer, a 3-roll mill, a ball mill, a bead mill, a homodisper, etc.

[0104] The substrate is not particularly limited as long as it has heat resistance that can withstand the heating conditions when volatilizing organic solvents. Examples of such substrates include stretched polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymers, etc. (for example, films).

[0105] The heating conditions for volatilizing the organic solvent from the varnish composition applied to the substrate can be appropriately set according to the organic solvent used. For example, the heating conditions may be 40 to 120°C for 0.1 to 10 minutes.

[0106] When light is used in the curing process, it is preferable to use irradiation light (e.g., ultraviolet light) that includes wavelengths in the range of 150 to 750 nm. Irradiation can be carried out using, for example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, metal halide lamps, LED light sources, etc. The integrated light intensity of the irradiation can be set as appropriate, but for example, 500 to 3000 mJ / cm². 2 That's fine.

[0107] The second step is to laminate a second adhesive layer onto the first adhesive layer. In the second step, for example, first, a second adhesive layer is formed on the substrate in the same manner as in the first step, except that component (C) and other components and additives added as needed are used, and light irradiation is not performed, thereby obtaining a second adhesive film. Then, the second adhesive layer can be laminated onto the first adhesive layer by bonding the first adhesive film and the second adhesive film together. Alternatively, in the second step, for example, the second adhesive layer can also be laminated onto the first adhesive layer by applying a varnish composition obtained using component (C) and other components and additives added as needed onto the first adhesive layer and volatilizing the organic solvent.

[0108] Methods for bonding the first adhesive film and the second adhesive film include, for example, heat pressing, roll lamination, and vacuum lamination. Lamination can be carried out, for example, under temperature conditions of 0 to 80°C.

[0109] The third step is to laminate the third adhesive layer onto the layer of the first adhesive layer opposite to the second adhesive layer. In the third step, for example, first, the third adhesive layer is formed on the substrate in the same manner as in the second step to obtain the third adhesive film. Then, the third adhesive layer can be laminated onto the layer of the first adhesive layer opposite to the second adhesive layer by laminating the third adhesive film to the side of the first adhesive film opposite to the second adhesive film. Alternatively, in the third step, for example, the second adhesive layer can also be laminated onto the first adhesive layer by applying a varnish composition to the layer of the first adhesive layer opposite to the second adhesive layer and volatilizing the organic solvent, in the same manner as in the second step. The lamination method and conditions are the same as in the second step.

[0110] <Circuit connection structure and method for manufacturing the same> The following describes a circuit connection structure using the above-mentioned circuit connection adhesive film 10 as a circuit connection material, and a method for manufacturing the same.

[0111] Figure 2 is a schematic cross-sectional view showing one embodiment of a circuit connection structure. As shown in Figure 2, the circuit connection structure 20 includes a first circuit board 11 and a first circuit member 13 having a first electrode 12 formed on the 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 the 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, which electrically connects the first electrode 12 and the second electrode 15 to each other.

[0112] The first circuit member 13 and the second circuit member 16 may be the same or different from each other. 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 circuit board; a ceramic circuit board; a flexible circuit board; an IC chip such as a driver IC, etc. The first circuit board 11 and the second circuit board 14 may be made of an inorganic material such as a semiconductor, glass, or ceramic; an organic material such as polyimide or polycarbonate; a composite material such as glass / epoxy, etc. The first circuit board 11 may be a glass substrate. The first circuit member 13 may be, for example, a glass substrate on which circuit electrodes are formed, and the second circuit member 16 may be, for example, an IC chip such as a driver IC.

[0113] 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 also be electrodes formed by laminating two or more of these metals, oxides, etc. The electrodes formed by laminating two or more types may have two or more layers, or three or more layers. If 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. Figure 2 shows an embodiment in which the first electrode 12 is a circuit electrode and the second electrode 15 is a bump electrode.

[0114] The circuit connection portion 17 includes the cured product of the adhesive film 10 described above. The circuit connection portion 17 may consist of the cured product of the adhesive film 10 described above. The circuit connection portion 17 includes, for example, 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"), which consists of cured product of component (B) and component (C), other than the conductive particles 4 in the first adhesive layer described above; a second region 19 located on the second circuit member 16 side in the facing direction, which consists of cured product of component (C), etc., in the second adhesive layer described above; 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 Figure 2, the circuit connection portion 17 does not necessarily have two distinct regions between the first region 18 and the second region 19; the cured material derived from the first adhesive layer and the cured material derived from the second adhesive layer may be mixed together to form a single region.

[0115] Examples of circuit connection structures include a flexible organic electroluminescent color display (organic EL display) in which a plastic substrate with regularly arranged organic EL elements is connected to a drive circuit element that acts as a driver for displaying images, and a touch panel in which a plastic substrate with regularly arranged organic EL elements is connected to a position input element such as a touchpad. Circuit connection structures can be applied to various monitors such as smartphones, tablets, televisions, vehicle navigation systems, and wearable devices; furniture; home appliances; and daily necessities.

[0116] Figure 3 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a circuit connection structure. Figures 3(a) and 3(b) are schematic cross-sectional views showing each step. As shown in Figure 3, the method for manufacturing the circuit connection structure 20 includes the step of interposing the adhesive film 10 described above between a first circuit member 13 having a first electrode 12 and a second circuit member 16 having a second electrode 15, and then heat-pressing the first circuit member 13 and the second circuit member 16 together to electrically connect the first electrode 12 and the second electrode 15 to each other.

[0117] Specifically, as shown in Figure 3(a), first, a first circuit member 13 comprising 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 comprising a second circuit board 14 and a second electrode 15 formed on the main surface 14a of the second circuit board 14 are prepared.

[0118] 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 Figure 3(a), the adhesive film 10 is laminated onto the first circuit member 13 so that the side with 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, to 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.

[0119] Then, as shown in Figure 3(b), the first circuit member 13, the adhesive film 10, and the second circuit member 16 are heated, and the first circuit member 13 and the second circuit member 16 are pressed together in the thickness direction, thereby thermocompressing them together. At this time, as indicated by the arrows in Figure 3(b), the second adhesive layer 2 has a flowable, uncured thermosetting component, so it flows to fill the gaps between the second electrodes 15 and hardens due to 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 Figure 2. In the manufacturing method of the circuit connection structure 20 of this embodiment, a portion of the first adhesive layer 1 is hardened by light, heat, moisture, etc., so the first adhesive layer 1 hardly flows during the heat-compression bonding, and conductive particles are efficiently captured between opposing electrodes, thereby reducing the connection resistance between the opposing first electrode 12 and second electrode 15. Furthermore, when the thickness of the first adhesive layer is 5 μm or less, conductive particles during circuit connection tend to be captured even more efficiently.

[0120] The heating temperature for heat-compression bonding can be set as appropriate, but for example, it may be between 50 and 190°C. The pressurization is not particularly limited as long as it does not damage the adherend, but in the case of COG mounting, for example, the area-equivalent pressure at the bump electrode may be between 10 and 100 MPa. The heating and pressurization times may be in the range of 0.5 to 120 seconds. In the case of COP (chip on plastic) mounting, for example, the area-equivalent pressure at the bump electrode may be between 0.1 and 50 MPa. [Examples]

[0121] The present disclosure will be described in more detail below with reference to examples. However, the present disclosure is not limited to these examples.

[0122] [Preparation of the first adhesive layer and the second adhesive layer] The following materials were used in the preparation of the first and second adhesive layers.

[0123] (A) Component: Conductive particles Conductive particle A-1: ​​Uses insulating coated conductive particles with an average particle size of 3.2 μm, consisting of a plastic core with a nickel plating on the surface and an insulating coating on the outermost surface.

[0124] (B) component: curable resin component and (C) component: thermosetting resin component Component (B) and component (C) were selected from the following (MA) polymerizable compounds and (MB) polymerization initiators, as shown in Table 1. By combining (MA-R) radical polymerizable compounds with (MB-RL) photoradical polymerization initiators, they can be made to act as photocurable resin components. On the other hand, by combining (MA-R) radical polymerizable compounds with (MB-RH) thermal radical polymerization initiators, they can be made to act as thermosetting components. Furthermore, by combining (MA-C) cationic polymerizable compounds with (MB-CL) photocationic polymerization initiators, they can be made to act as photocurable components. On the other hand, by combining (MA-C) cationic polymerizable compounds with (MB-CH) thermal cationic polymerization initiators, they can be made to act as thermosetting components.

[0125] (MA)Polymerizable compound (MA-R) Radical polymerizable compound Radical polymerizable compound MA-R-1:HA7663 (phenol novolac type epoxy (meth)acrylate (polyfunctional), manufactured by Showa Denko Materials Co., Ltd.) Radical polymerizable compound MA-R-2:VR-90 (Bisphenol A type epoxy (meth)acrylate (bifunctional) (vinyl ester resin), manufactured by Showa Denko Corporation) Radical polymerizable compound MA-R-3:DCP-A (dimethylol-tricyclodecanediaacrylate (bifunctional), manufactured by Kyoeisha Chemical Co., Ltd.) (MA-C) Cationic polymerizable compound Cationic polymerizable compound MA-C-1:CEL2021P (3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (alicyclic epoxy compound), manufactured by Daicel Corporation) Cationic polymerizable compound MA-C-2:YL980 (Bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation) (MB) polymerization initiator (MB-RL) Photoradical polymerization initiator Photoradical polymerization initiator MB-RL-1:DAROCURE-TPO (diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, manufactured by BASF) (MB-RH) Thermal radical polymerization initiator Thermal radical polymerization initiator MB-RH-1: Perhexa 25O (2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, manufactured by NOF Corporation) (MB-CL) Photocation polymerization initiator Photocationic polymerization initiator MB-CL-1:CPI-101A (triarylsulfonium SbF6 salt, manufactured by Sunapro Co., Ltd.) (MB-CH) Thermal Cationic Polymerization Initiator Thermal cationic polymerization initiator MB-CH-1:SI-60 (aromatic sulfonium SbF6 salt, manufactured by Sanshin Chemical Industry Co., Ltd.)

[0126] (D) Component: Thermoplastic resin Thermoplastic resin D-1: PKHC (phenoxy resin, manufactured by Union Carbide)

[0127] (E) Component: Filler Filler E-1: SE2050 (Silica microparticles, manufactured by Admatex Co., Ltd., average particle size: 0.5 μm)

[0128] <Preparation of the first adhesive film (first adhesive layer)> A composition was obtained by mixing the materials shown in Table 1 in the composition ratio shown in Table 1 (the values ​​in Table 1 represent the amount of solids). Then, on a 38 μm thick PET (polyethylene terephthalate) film (manufactured by Mitsui Chemicals Tohcello Co., Ltd.), a composition with a dry thickness of 3 μm and a conductive particle count of 22,000 particles / mm² was obtained. 2 The mixture was coated in such a manner, and then dried in an oven at 60°C / 1 minute to obtain composition layers 1a to 1e containing each component. For composition layers 1a, 1b, and 1e, ultraviolet light was irradiated using an ultraviolet irradiation device (irradiation dose: 1500 mJ / cm²). 2 By doing so, first adhesive films 1A, 1B, and 1E were obtained. With respect to composition layer 1c, first adhesive film 1C was obtained by further drying in an oven at 70°C / 4 minutes. With respect to composition layer 1d, it was used as is as first adhesive film 1D.

[0129] [Table 1]

[0130] <Preparation of the second adhesive film (second adhesive layer)> The materials shown in Table 2 were mixed in the composition ratio shown in Table 2 (the values ​​in Table 2 represent the amount of solids). The mixture was then coated onto a 38 μm thick PET (polyethylene terephthalate) film (manufactured by Toyobo Film Solutions Co., Ltd.) to a dry thickness of 12 μm, and dried in an oven at 60°C for 3 minutes to obtain a second adhesive film 2A.

[0131] [Table 2]

[0132] (Examples 1-3 and Comparative Examples 1 and 2) [Fabrication of adhesive film] Using the first and second adhesive films prepared as described above, adhesive films with the configurations shown in Table 3 were manufactured. For the adhesive films of Examples 1-3 and Comparative Examples 1 and 2, the first adhesive film was bonded to the second adhesive film while applying a temperature of 50-60°C to produce adhesive films with the configurations shown in Table 3.

[0133] [Evaluation of transcriptional properties] The adhesive films of Examples 1-3 and Comparative Examples 1 and 2 were cut to 2.5 mm x 25 mm. The side of the first adhesive film (first adhesive layer) was pre-pressed onto the glass substrate by heating and pressing for 1 second under conditions of a maximum temperature of 90°C and an area-converted pressure of 1 MPa at the bump electrode. After pre-pressing, the PET film of the second adhesive film (second adhesive layer) was grasped with tweezers and peeled off from the second adhesive layer. At this time, if the adhesive film was adhered to the glass substrate, it was evaluated as having excellent transferability and was rated as "A". If the adhesive film lifted from the glass substrate or was completely peeled off from the glass substrate, it was evaluated as "B". The results are shown in Table 3.

[0134] [Measurement of peel strength] First, a glass substrate with ITO wiring was prepared (glass substrate size: 2.5 mm × 28 mm, glass substrate thickness: 300 μm, ITO wiring size: 2500 μm (2.5 mm) × 300 μm, ITO wiring thickness: 0.2 μm, number of ITO wirings: 28, space between ITO wirings: 300 μm). The adhesive films of Examples 1-3 and Comparative Examples 1 and 2 were cut to 2 mm × 23 mm, and the first adhesive film (first adhesive layer) of the cut adhesive film was placed on the glass substrate with ITO wiring perpendicular to the ITO wiring. Then, the adhesive film was bonded using a thermocompression press at a temperature of 60°C, an area-converted pressure of 1 MPa for the first adhesive layer, and a time of 1 second to obtain a laminate. Figure 4 is a schematic top view showing the laminate in the peel strength measurement of the example. The laminate 30 shown in Figure 4 comprises a glass substrate 33 having ITO wiring (a substrate including a glass substrate 31 and ITO wiring 32 provided on the glass substrate 31) and an adhesive film 10A disposed on the glass substrate 33 having ITO wiring. Next, the PET film of the second adhesive film (second adhesive layer) was peeled off, and a polyimide tape cut to 1.8 mm × 35 mm was attached to the second adhesive layer to obtain a sample for measurement. The glass substrate side of the sample for measurement was placed on a hot plate set to 40°C, and the tip of the polyimide tape was set in a tensile strength measuring device (Tensilon). The glass substrate was fixed horizontally, and the polyimide tape was pulled vertically at a peeling speed of 50 mm / min to measure the peel strength at 40°C between the attached glass substrate and the first adhesive layer, where the peeling angle was 90°. The results are shown in Table 3.

[0135] [Evaluation of connection resistance, indentation strength, and trapping rate of conductive particles] (Preparation of circuit components) As the first circuit component, a glass substrate with ITO wiring was prepared (glass substrate size: 3.8 mm × 28 mm, glass substrate thickness: 300 μm, ITO wiring size: 105 μm × 18 μm, ITO wiring thickness: 0.2 μm, space between ITO wirings: 6 μm). As the second circuit component, an IC chip with gold bump electrodes was prepared (IC chip size: 0.9 mm × 20.3 mm, IC chip thickness: 0.3 mm, gold bump electrode size: 12 μm × 100 μm, gold bump electrode thickness: 12 μm, space between gold bump electrodes: 24 μm).

[0136] (Fabrication of circuit connection structures) Circuit connection structures were constructed using the adhesive films of Examples 1-3 and Comparative Examples 1 and 2. The adhesive film was cut to 2 mm x 23 mm and placed on the first circuit member so that the first adhesive layer of the cut adhesive film was in contact with the circuit electrodes of the first circuit member. Using a thermocompression bonding device (BS-17U, manufactured by Ohashi Seisakusho Co., Ltd.) consisting of a ceramic heater stage and a tool (8 mm x 50 mm), the adhesive film was attached to the first circuit member by heating and pressurizing for 5 seconds at 130°C and 40 MPa. Next, the PET film on the side of the adhesive film opposite to the first circuit member was peeled off, and the circuit electrodes of the first circuit member and the bump electrodes of the second circuit member were aligned. Then, the second adhesive layer of the adhesive film was attached to the second circuit member by heating and pressurizing for 5 seconds at the measured maximum temperature of the adhesive film (130°C) and the area-converted pressure at the bump electrodes (40 MPa), thereby fabricating a circuit connection structure.

[0137] (Evaluation of connection resistance) The connection resistance of the obtained circuit connection structure was evaluated. The connection resistance was evaluated using the four-terminal measurement method, and the average value of the connection resistance values ​​measured at 14 locations was used for evaluation. A multimeter (MLR21, manufactured by Kusumoto Kasei Co., Ltd.) was used for measurement. The results are shown in Table 3.

[0138] (Evaluation of indentation strength) The indentation strength of the obtained circuit connection structures was evaluated. Using a differential interference microscope, electrodes were observed through a glass substrate, and indentations were observed at the connection points of the IC chip's edges and center. The observed indentations were captured as image data, and their strength was evaluated on a 5-point scale (1, 2, 3, 4, 5) using indentation analysis software. A higher numerical value indicates greater indentation strength. Higher indentation strength tends to indicate superior connection stability. The results are shown in Table 3.

[0139] (Evaluation of the trapping rate of conductive particles) The obtained circuit connection structure was observed using a differential interference microscope, and the number of conductive particles trapped between electrodes was measured. The number of trapped conductive particles per electrode area was then calculated. 100 electrodes were used as the observation target, and the average value was taken as the number of trapped conductive particles per electrode area. The conductive particle trapping rate was calculated using the following formula. The results are shown in Table 3. Conductive particle capture rate (%) = (Number of conductive particles captured between electrodes per electrode area (particles / mm²) 2 ) / Number of conductive particles per unit area of ​​adhesive film (particles / mm²) 2 )) × 100

[0140] [Evaluation of the flowability of conductive particles] Samples were prepared by punching out 1 mm diameter pieces of adhesive film from Examples 1-3 and Comparative Examples 1 and 2 using a trepanning apparatus. The side of the punched sample with the first adhesive film (first adhesive layer) was heated and pressurized for 1 second under conditions of a maximum temperature of 90°C and a film area equivalent pressure of 1 MPa, and then attached to a cover glass. This was used as a test specimen (pre-pressure test specimen) for measuring the area of ​​the first adhesive layer before bonding. Next, the PET film on the second adhesive film (second adhesive layer) side was peeled off, and a cover glass was placed on top. Then, the second adhesive film (second adhesive layer) and the cover glass were bonded together under conditions of a maximum temperature of 170°C and a film area equivalent pressure of 80 MPa for 5 seconds. This was used as a test specimen (post-pressure test specimen) for measuring the area of ​​the first adhesive layer after bonding. The area of ​​the first adhesive layer on the pre-pressure test specimen and the area of ​​the first adhesive layer on the post-pressure test specimen were measured with a microscope, and the flow rate of conductive particles was calculated using the following formula. The results are shown in Table 3. Flow rate of conductive particles (%) = (Area of ​​the first adhesive layer on the test specimen after crimping / Area of ​​the first adhesive layer on the test specimen before crimping) × 100

[0141] [Table 3]

[0142] As shown in Table 3, the adhesive films of Examples 1 to 3 were excellent in all aspects. On the other hand, the adhesive film of Comparative Example 1, which had a predetermined peel strength exceeding 60 N / m, did not have a sufficient capture rate of conductive particles. This is thought to be because the hardness of the resin was too soft from the viewpoint of resin fluidity. Furthermore, the adhesive film of Comparative Example 2, which had a predetermined peel strength of less than 20 N / m, did not have sufficient connection resistance, and was also insufficient in terms of transferability and indentation strength. This is thought to be because the hardness of the resin was too hard from the viewpoint of resin fluidity. From these results, it was confirmed that the adhesive film of this disclosure can improve the capture rate of conductive particles between opposing electrodes of a circuit connection structure and reduce connection resistance. [Explanation of symbols]

[0143] 1...First adhesive layer, 2...Second adhesive layer, 4...Conductive particles, 5...Adhesive component, 10...Adhesive film for circuit connection (adhesive film), 10A...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 part, 20...Circuit connection structure, 30...Laminate, 31...Glass substrate, 32...ITO wiring, 33...Glass substrate having ITO wiring.

Claims

1. A first adhesive layer containing conductive particles, a cured product of a curable resin component, and a first thermosetting resin component, A second adhesive layer containing a second thermosetting resin component is provided on the first adhesive layer, A circuit connection adhesive film comprising, The curable resin component includes a radical polymerizable compound, The first thermosetting resin component and the second thermosetting resin component each contain a cationic polymerizable compound. A circuit connection adhesive film in which, when the first adhesive layer of the circuit connection adhesive film is applied to a glass substrate having indium tin oxide (ITO) wiring by processing it under the conditions of a temperature of 60°C, an area-equivalent pressure of 1 MPa for the first adhesive layer, and a time of 1 second, the peel strength between the glass substrate and the first adhesive layer at 40°C after application is 20 to 60 N / m.

2. The circuit connection adhesive film according to claim 1, wherein the curable resin component is photocurable.

3. The circuit connection adhesive film according to claim 1, wherein the curable resin component is thermosetting.

4. The circuit connection adhesive film according to any one of claims 1 to 3, wherein the thickness of the first adhesive layer is 5 μm or less.

5. A step of forming a first adhesive layer by curing the curable resin component on a layer made of a composition containing conductive particles, a curable resin component, and a first thermosetting resin component, A step of obtaining a circuit connection adhesive film by providing a second adhesive layer containing a second thermosetting resin component on the first adhesive layer, Equipped with, The curable resin component includes a radical polymerizable compound, The first thermosetting resin component and the second thermosetting resin component each contain a cationic polymerizable compound. A method for manufacturing a circuit connection adhesive film, wherein when the first adhesive layer of the circuit connection adhesive film is attached to a glass substrate having indium tin oxide (ITO) wiring by processing it under the conditions of a temperature of 60°C, an area-equivalent pressure of 1 MPa for the first adhesive layer, and a time of 1 second, the peel strength between the glass substrate and the first adhesive layer at 40°C after attachment is 20 to 60 N / m.

6. A method for manufacturing an adhesive film for circuit connections according to claim 5, wherein the curable resin component is photocurable.

7. A method for manufacturing an adhesive film for circuit connections according to claim 5, wherein the curable resin component is thermosetting.

8. A method for manufacturing an adhesive film for circuit connection according to any one of claims 5 to 7, wherein the thickness of the first adhesive layer is 5 μm or less.

9. A method for manufacturing a circuit connection structure, comprising the steps of interposing a circuit connection adhesive film according to any one of claims 1 to 4 between a first circuit member having a first electrode and a second circuit member having a second electrode, and then heat-pressing the first circuit member and the second circuit member together to electrically connect the first electrode and the second electrode.

10. A first circuit member having a first electrode, A second circuit member having a second electrode, A circuit connection portion is disposed between the first circuit member and the second circuit member and electrically connects the first electrode and the second electrode to each other, Equipped with, A circuit connection structure wherein the circuit connection portion includes a cured product of the circuit connection adhesive film described in any one of claims 1 to 4.

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