WO2022102573A1

WO2022102573A1 - Circuit-connection adhesive film and method for producing same, and circuit connection structure and method for producing same

Info

Publication number: WO2022102573A1
Application number: PCT/JP2021/040989
Authority: WO
Inventors: 智陽山崎; 剛幸市村; 亮太小林; 華世稗島
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2020-11-10
Filing date: 2021-11-08
Publication date: 2022-05-19
Also published as: TW202224942A; JPWO2022102573A1

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

Adhesive film for circuit connection and its manufacturing method, and circuit connection structure and its manufacturing method

The present disclosure relates to an adhesive film for circuit connection, a circuit connection structure, and a method for manufacturing the same.

Conventionally, for example, in the connection between a liquid crystal display and a tape carrier package (TCP), the connection between a flexible printed circuit board (FPC) and TCP, or the connection between an FPC and a printed wiring board, conductive particles are used in an adhesive film. A dispersed anisotropic conductive film is used. Specifically, the circuit members are bonded to each other by the circuit connection portion formed of the circuit connection adhesive film, and the electrodes on the circuit members are electrically connected to each other via the conductive particles in the circuit connection portion. By doing so, a circuit connection structure can be obtained. Also, when mounting a semiconductor silicon chip on a substrate, so-called chip on glass (COG) mounting, in which the semiconductor silicon chip is directly mounted on the board, is performed instead of the conventional wire bonding, and COG mounting is also performed. An anisotropic conductive film is used.

In the field of precision electronic devices in which an adhesive film for circuit connection having anisotropic conductivity is used, the density of circuits is increasing, and the electrode spacing is extremely narrow, for example, 15 μm or less. Further, the bump electrode of the connecting member is also becoming smaller in area. In such a small-area electrode, in order to obtain a stable electrical connection, it is necessary that a sufficient number of conductive particles are interposed between the bump electrode and the circuit electrode on the substrate side.

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

International Publication No. 2005/054388

However, in the method of Patent Document 1, the conductive particles may flow out from between the opposing electrode circuits due to the flow of the conductive particles at the time of circuit connection, and there is still room for improvement in terms of the capture rate of the conductive particles.

On the other hand, for example, it is also considered to cure the adhesive of the adhesive film for circuit connection by heat or light to suppress the fluidity of the conductive particles and improve the capture rate of the conductive particles. However, in this case, since the removability of the resin in the adhesive is also lowered, it is presumed that the connection resistance is increased.

Therefore, the main object of the present disclosure is to provide an adhesive film for circuit connection capable of improving the capture rate of conductive particles between facing electrodes of a circuit connection structure and reducing the connection resistance. do.

One aspect of this disclosure relates to an adhesive film for circuit connection. The circuit connection adhesive film is provided on a first adhesive layer containing conductive particles, a cured product of a curable resin component, and a first thermosetting resin component, and a first adhesive layer. Further, it includes a second adhesive layer containing a second thermosetting resin component. The circuit connection adhesive film is formed by placing a first adhesive layer of the circuit connection adhesive film on a glass substrate having indium tin oxide (ITO) wiring at a temperature of 60 ° C. and an area of the first adhesive layer. When the glass substrate and the first adhesive layer are pasted after being treated under the conditions of a converted pressure of 1 MPa and a time of 1 second, the peel strength at 40 ° C. is 20 to 60 N / m. When the peel strength is 60 N / m or less, the hardness of the resin is sufficient from the viewpoint of the fluidity of the resin, so that the fluidity of the resin at the time of mounting becomes small, and as a result, the capture rate of conductive particles is reduced. Can be improved. On the other hand, when the peel strength exceeds 60 N / m, the hardness of the resin is too soft from the viewpoint of the fluidity of the resin, so that the fluidity of the resin at the time of mounting is large and the capture rate of conductive particles tends to be insufficient. be. When the peel strength is 20 N / m or more, the hardness of the resin is sufficient from the viewpoint of the fluidity of the resin, so that the resin in the adhesive at the time of mounting is sufficiently eliminated, and as a result, the connection is made. It is possible to reduce the 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 the fluidity of the resin, so that the resin in the adhesive at the time of mounting is not sufficiently eliminated and the connection resistance is increased. It tends to rise. Further, when the peel strength is 20 N / m or more, preferably 20 to 60 N / m, the transferability to the glass substrate is excellent, and it is possible to obtain sufficient indentation strength in the circuit connection structure.

In one aspect of the circuit connection adhesive film, the curable resin component has photocurability. In another aspect of the circuit connection adhesive film, the curable resin component has thermosetting property.

The thickness of the first adhesive layer may be 5 μm or less. When the thickness of the first adhesive layer is 5 μm or less, conductive particles at the time of circuit connection can be captured more efficiently.

Another aspect of the present disclosure relates to a method for manufacturing an adhesive film for circuit connection. The method for producing an adhesive film for circuit connection is to cure a curable resin component on a layer composed of a composition containing conductive particles, a curable resin component, and a first thermosetting resin component. The process of forming the first adhesive layer and the second adhesive layer containing the second thermosetting resin component are provided on the first adhesive layer to form an adhesive film for circuit connection. Provided with the process of obtaining. The circuit connection adhesive film is formed by placing a first adhesive layer of the circuit connection adhesive film on a glass substrate having indium tin oxide (ITO) wiring at a temperature of 60 ° C. and an area of the first adhesive layer. When the glass substrate and the first adhesive layer are pasted after being treated under the conditions of a converted pressure of 1 MPa and a time of 1 second, the peel strength at 40 ° C. is 20 to 60 N / m. According to the method for manufacturing such a circuit connection adhesive film, a circuit connection adhesive capable of improving the capture rate of conductive particles between the facing electrodes of the circuit connection structure and reducing the connection resistance. Films can be manufactured.

Another aspect of this disclosure relates to a method of manufacturing a circuit connection structure. In the method for manufacturing the circuit connection structure, the above-mentioned circuit connection adhesive film is interposed between the first circuit member having the first electrode and the second circuit member having the second electrode. , A step of thermocompression-bonding a first circuit member and a second circuit member to electrically connect the first electrode and the second electrode to each other.

Another aspect of this disclosure relates to circuit connection structures. The circuit connection structure is arranged between a first circuit member having a first electrode, a second circuit member having a second electrode, and a first circuit member and a second circuit member. A circuit connection portion for electrically connecting the first electrode and the second electrode to each other is provided. The circuit connection portion includes a cured product of the above-mentioned circuit connection adhesive film.

According to the present disclosure, a circuit connection adhesive film capable of improving the capture rate of conductive particles between facing electrodes of a circuit connection structure and reducing the connection resistance is disclosed. The circuit-connecting adhesive film according to some forms has excellent transferability to a glass substrate, and it is possible to obtain sufficient indentation strength in the circuit connection structure. Further, the present disclosure discloses a method for producing such an adhesive film for circuit connection. Further, the present disclosure discloses a circuit connection structure using such a circuit connection adhesive film and a method for manufacturing the same.

FIG. 1 is a schematic cross-sectional view showing an embodiment of an adhesive film for circuit connection. FIG. 2 is a schematic cross-sectional view showing an embodiment of a circuit connection structure. FIG. 3 is a schematic cross-sectional view showing an embodiment of a method for manufacturing a circuit connection structure. 3 (a) and 3 (b) are schematic cross-sectional views showing each process. FIG. 4 is a schematic top view showing the laminated body in the peel strength measurement of the embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or corresponding parts will be designated by the same reference numerals, and duplicate description will be omitted. The present disclosure is not limited to the following embodiments. As used herein, the (meth) acryloyl group means an acryloyl group or a methacryloyl group, as well as other similar expressions such as (meth) acrylate. In the present specification, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. The lower and upper limits of the numerical range described herein are optionally combined with the lower and upper limits of the other numerical ranges, respectively. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. In addition, the upper limit value and the lower limit value described individually can be arbitrarily combined. In the notation of the numerical range "A to B", the numerical values A and B at both ends are included in the numerical range as the lower limit value and the upper limit value, respectively. In the present specification, for example, the description of "10 or more" means "10" and "a numerical value exceeding 10", and the same applies when the numerical values are different. Further, for example, the description "10 or less" means "10" and "a numerical value less than 10", and the same applies when the numerical values are different. Unless otherwise specified, each component and material exemplified in the present specification may be used alone or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified.

[Adhesive film for circuit connection]
FIG. 1 is a schematic cross-sectional view showing an embodiment of an adhesive film for circuit connection. The circuit connection adhesive film 10 (hereinafter, may be simply referred to as “adhesive film 10”) shown in FIG. 1 includes the conductive particles 4, the cured product of the curable resin component, and the first thermosetting property. A first adhesive layer 1 containing an adhesive component 5 containing a resin component, and a second adhesive layer provided on the first adhesive layer 1 containing a second thermosetting resin component. 2 and.

In the adhesive film 10, the conductive particles 4 are dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 can be a circuit-connecting adhesive film (anisotropic adhesive film) having anisotropic conductivity. The adhesive film 10 is interposed between the first circuit member having the first electrode and the second circuit member having the second electrode, and heats the first circuit member and the second circuit member. It may be crimped and used to electrically connect the first electrode and the second electrode to each other.

<First adhesive layer>
The first adhesive layer 1 is a cured product of conductive particles 4 (hereinafter, may be referred to as "(A) component") and a curable resin component (hereinafter, may be referred to as "(B) component"). , And a (first) thermosetting resin component (hereinafter, may be referred to as “(C) component”). The first adhesive layer 1 is formed by, for example, light, heat, moisture, or the like with respect to a composition layer composed of a composition containing the component (A), the component (B), and the component (C). It can be obtained by polymerizing the component contained in the component and curing the component (B). The first adhesive layer 1 contains the component (A), the cured product of the component (B), and the adhesive component 5 containing the component (C). The cured product of the component (B) may be a cured product obtained by completely curing the component (B), or may be a cured product obtained by curing a part of the component (B). The component (C) is a component that can flow when connected to a circuit, and is, for example, an uncured curable resin component.

Component (A): Conductive particles The component (A) is not particularly limited as long as it is a particle having conductivity, and is a metal particle composed of a metal such as Au, Ag, Pd, Ni, Cu, or solder, or conductive carbon. It may be conductive carbon particles composed of. The component (A) may be a coated conductive particle containing a nucleus containing non-conductive glass, ceramic, plastic (polystyrene, etc.) and the like, and a coating layer containing the metal or conductive carbon and covering the nucleus. good. Among these, the component (A) preferably contains metal particles formed of a heat-meltable metal or a core containing plastic, and contains a metal or conductive carbon and has a coating layer covering the core. It is a particle. Since such coated conductive particles can easily deform the cured product of the thermosetting resin component by heating or pressurizing, when the electrodes are electrically connected to each other, the electrode and the component (A) are connected to each other. The contact area can be increased and the conductivity between the electrodes can be further improved.

The component (A) may be an insulating coated conductive particle containing the above-mentioned metal particles, conductive carbon particles, or coated conductive particles and an insulating material such as a resin and having an insulating layer covering the surface of the particles. good. When the component (A) is an insulating coated conductive particle, even when the content of the component (A) is large, the insulating layer is provided on the surface of the particle, so that the component (A) is short-circuited due to contact with each other. The generation can be suppressed, and the insulation between adjacent electrode circuits can be improved. As the component (A), one of the above-mentioned various conductive particles may be used alone or in combination of two or more.

The maximum particle size of the component (A) needs to be smaller than the minimum distance between the electrodes (the shortest distance between adjacent electrodes). The maximum particle size of the 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 the component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less from the viewpoint of excellent dispersibility and conductivity. In the present 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 the maximum particle size of the component (A). And. When the component (A) is not spherical, such as when the component (A) has protrusions, the particle size of the component (A) is the diameter of a circle circumscribing the conductive particles in the SEM image.

The average particle size of the component (A) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The average particle size of the component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less from the viewpoint of excellent dispersibility and conductivity. In the present 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 taken as the average particle size.

In the first adhesive layer 1, the component (A) is preferably uniformly dispersed. The particle density of the component (A) in the adhesive film 10 is 100 pieces / mm ² or more, 1000 pieces / mm ² or more, 3000 pieces / mm ² or more, or 5000 pieces / mm from the viewpoint of obtaining stable connection resistance. It may be ² or more. The particle density of the component (A) in the adhesive film 10 is 100,000 pieces / mm ² or less, 70,000 pieces / mm ² or less, 50,000 pieces / mm ² or less, or 30,000 from the viewpoint of improving the insulating property between adjacent electrodes. Pieces / mm ² or less may be used.

The content of the component (A) is 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 the conductivity. It may be there. The content of the 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 a short circuit. When the content of the component (A) is in the above range, the effect of the present disclosure tends to be remarkably exhibited. The content of the component (A) in the composition or the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

Component (B): Curable resin component As the component (B), a photocurable resin component (photocurable resin component), a thermosetting resin component (thermosetting resin component), and the like. Examples thereof include a curable resin component having a moisture-curable property (moisture-curable resin component). Here, the thermosetting resin component may be different from the component (C) described later in, for example, a curing system (for example, a radical curing system, a cationic curing system, etc.), a polymerization start temperature, and the like. The polymerization start temperature can be adjusted depending on the type of the polymerization initiator and the like. The thermosetting resin component of the component (B) may have a lower polymerization initiation temperature than the thermosetting resin component of the component (C). The component (B) may be a photocurable resin component or a thermosetting resin component, and more preferably a photocurable resin component. The component (B) may be referred to as a polymerizable compound (hereinafter, “MA component”). ) And the polymerization initiator (hereinafter, "MB component"). ) May be combined.

The photocurable resin component may be a resin component having radical curability or a resin component having cation curability. The resin component having radical curability in the photocurable resin component is, for example, a radically polymerizable compound (hereinafter, may be referred to as “(MA-R) component”) and a photoradical polymerization initiator (hereinafter, “(MB)”. -RL) component "may be combined with.). The cationically curable resin component in the photocurable resin component is, for example, a cationically polymerizable compound (hereinafter, may be referred to as “(MA-C) component”) and a photocationic polymerization initiator (hereinafter, “(MB)”. -C-L) component "may be combined with.).

The thermosetting resin component may be a resin component having radical curability or a resin component having cation curability. The resin component having radical curability in the thermosetting resin component is, for example, a (MA-R) component and a thermo-radical polymerization initiator (hereinafter, may be referred to as “(MB-RH) component”). It can be a combination. The cationically curable resin component in the thermosetting resin component is, for example, a (MA-C) component and a thermocationic polymerization initiator (hereinafter, may be referred to as "(MB-CH) component"). It can be a combination.

It is preferable that the component (B) and the component (C) described later have different curing systems (for example, radical curing system, cationic curing system, etc.). Since the curing system of the component (B) and the curing system of the component (C) are different, it is possible to selectively and efficiently cure only the component (B). More specifically, when a thermosetting resin component having cation curability (for example, a combination of (MA-C) component and (MB-CH) component) is used as the component (C), (B) The component is a photocurable resin component having radical curability (for example, a combination of (MA-R) component and (MB-RL) component) or a thermosetting resin component having radical curability (for example, (for example,). It may be a combination of the MA-R) component and the (MB-RH) component), and more preferably a photocurable resin component having radical curability. When a thermosetting resin component having radical curability (for example, a combination of (MA-R) component and (MB-RH) component) is used as the component (C), the component (B) is cationically curable. With a photocurable resin component having (for example, a combination of (MA-C) component and (MB-C-L) component) or a thermosetting resin component having cationic curability (for example, (MA-C) component). It may be (combination with (MB—CH) component), and more preferably a photocurable resin component having cation curability.

(MA-R) component: The radically polymerizable compound (MA-R) component is polymerized by radicals generated from a radical polymerization initiator ((MB-RL) component, (MB-RH) component, etc.). It is a compound. The (MA-R) component may be either a monomer or a polymer (or oligomer) obtained by polymerizing one or more kinds of monomers. The (MA-R) component may be used alone or in combination of two or more.

The (MA-R) component is a compound having a radically polymerizable group that reacts with a radical. Examples of the radically polymerizable group include (meth) acryloyl group, vinyl group, allyl group, styryl group, alkenyl group, alkenylene group, maleimide group and the like. The number of radically polymerizable groups (number of functional groups) contained in the (MA-R) component is such that the desired melt viscosity can be easily obtained after polymerization, the effect of reducing the connection resistance is further improved, and the connection reliability is improved. It may be 2 or more, and may be 10 or less from the viewpoint of suppressing curing shrinkage during polymerization. Further, in order to balance the crosslink density and the curing shrinkage, in addition to the compound having the number of radically polymerizable groups within the above range, a compound having the number of radically polymerizable groups outside the above range may be used. good.

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

Examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. ) Acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethoxylated polypropylene glycol Di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentylglycoldi (meth) acrylate, 3-methyl-1,5-pentanediol di (Meta) 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, glycerindi (meth) acrylate, tricyclodecanedimethanol (meth) acrylate, 2-methyl-1,3-propanediol di (meth) acrylate ethoxylated, trimethylolpropane tri (Meta) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated Pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated propoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, propoxydated Fat group (meth) acrylates such as pentaerythritol tetra (meth) acrylate, ethoxylated propoxylated pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexa (meth) acrylate; ethoxylated bisphenol A type di ( Meta) Acrylate Relate, 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 Aromatic (meth) acrylates such as propoxylated bisphenol F-type di (meth) acrylates, ethoxylated fluorene-type di (meth) acrylates, propoxylated fluorene-type di (meth) acrylates, and ethoxylated propoxylated fluorene-type di (meth) acrylates. Examples thereof include aromatic epoxy (meth) acrylates such as bisphenol type epoxy (meth) acrylate, phenol novolac type epoxy (meth) acrylate, and cresol novolac type epoxy (meth) acrylate.

The content of the polyfunctional (bifunctional or higher) (meth) acrylate is, for example, 40, based on the total mass of the (MA-R) component, from the viewpoint of achieving both the effect of reducing the connection resistance and the suppression of particle flow. It may be up to 100% by mass, 50 to 100% by mass, or 60 to 100% by mass.

The (MA-R) component may further contain a monofunctional (meth) acrylate in addition to the polyfunctional (bifunctional or higher) (meth) acrylate. Examples of the monofunctional (meth) acrylate include (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and 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, ethoxy Acrylate (meth) acrylates such as polyethylene glycol (meth) acrylates, methoxypolypropylene glycol (meth) acrylates, ethoxypolypropylene glycol (meth) acrylates, and mono (2- (meth) acryloyloxyethyl) succinates; benzyl (meth) acrylates. , 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, phenoxypolyethylene 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, 2- Aromatic (meth) acrylates such as hydroxy-3- (2-naphthoxy) propyl (meth) acrylates; (meth) acrylates having an epoxy group such as glycidyl (meth) acrylates, 3,4-epoxycyclohexylmethyl (meth) acrylates. (Meta) acrylates having an alicyclic epoxy group such as, ( Examples thereof include (meth) acrylate having an oxetanyl group such as 3-ethyloxetane-3-yl) methyl (meth) acrylate.

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

The cured product of the component (B) may have, for example, a polymerizable group that reacts with a substance other than a radical. The polymerizable group that reacts with a non-radical substance may be, for example, a cationically polymerizable group that reacts with a cation. Examples of the cationically polymerizable group include an epoxy group such as a glycidyl group, an alicyclic epoxy group such as an epoxycyclohexylmethyl group, and an oxetanyl group such as an ethyloxetanylmethyl group. The cured product of the component (B) having a polymerizable group that reacts by other than radicals is, for example, a (meth) acrylate having an epoxy group, a (meth) acrylate having an alicyclic epoxy group, and a (meth) acrylate having an oxetanyl group. It can be introduced by using a (meth) acrylate having a polymerizable group that reacts with a non-radical substance such as (B) as a component (B). Mass ratio of (meth) acrylate having a polymerizable group that reacts with other than radicals to the total mass of the (MA-R) component (mass ratio of (meth) acrylate having a polymerizable group that reacts with other than radicals (charged amount) / ( The total mass (charged amount) of the MA-R) component may be, for example, 0 to 0.7, 0 to 0.5, or 0 to 0.3 from the viewpoint of improving reliability.

The (MA-R) component may contain other radically polymerizable compounds in addition to polyfunctional (bifunctional or higher) and monofunctional (meth) acrylates. Examples of other radically polymerizable compounds include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, nadiimide derivatives and the like. The content of the other radically polymerizable compound may be, for example, 0 to 40% by mass based on the total mass of the (MA-R) component.

(MB-RL) component: Photoradical polymerization initiator (MB-RL) component is light containing a wavelength in the range of 150 to 750 nm, preferably light containing a wavelength in the range of 254 to 405 nm. More preferably, it is a polymerization initiator that generates radicals by irradiation with light having a wavelength of 365 nm (for example, ultraviolet light). The (MB-RL) component may be used alone or in combination of two or more.

The (MB-RL) component is decomposed by light to generate free radicals. That is, the (MB-RL) component is a compound that generates radicals by applying light energy from the outside. The (MB-RL) component includes an oxime ester structure, a bisimidazole structure, an acrydin structure, an α-aminoalkylphenone structure, an aminobenzophenone structure, an N-phenylglycine structure, an acylphosphine oxide structure, a benzyldimethylketal structure, and α-. It may be a compound having a structure such as a hydroxyalkylphenone structure. The (MB-RL) component may be used alone or in combination of two or more. The (MB-RL) component is composed of an oxime ester structure, an α-aminoalkylphenone structure, and an acylphosphine oxide structure from the viewpoint that the desired melt viscosity can be easily obtained and the effect of reducing the connection resistance is superior. It may be a compound having at least one structure selected from the group.

Specific examples of the compound having an oxime ester structure include 1-phenyl-1,2-butandion-2- (o-methoxycarbonyl) oxime and 1-phenyl-1,2-propanedione-2- (o-methoxycarbonyl). ) Oxime, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 1,3-diphenylpropantrione- 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 the like.

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

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

The content of the (MB-RL) component is, for example, 0.1 to 10 parts by mass and 0.3 to 0.3 to 100 parts by mass with respect to 100 parts by mass of the (MA-R) component from the viewpoint of suppressing the flow of conductive particles. It may be 7 parts by mass or 0.5 to 5 parts by mass.

(MB-RH) component: Thermal radical polymerization initiator (MB-RH) component is a polymerization initiator that generates radicals by heat. The 1-hour half-life temperature of the (MB-RH) component may be, for example, 50-100 ° C. The (MB-RH) component may be used alone or in combination of two or more.

Examples of the (MB-RH) component include diacyl peroxides such as octanoyl peroxide, lauroyl peroxide, stearyl peroxide, and benzoyl peroxide; t-butylperoxypivalate and t-hexylperoxypivalate. , 1,1,3,3-Tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy- 2-Ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy-3,5,5- Trimethylhexanoate, t-butylperoxylaurylate, t-butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexylmonocarbonate, t-butylperoxybenzoate, t-hexylperoxybenzoate, 2, Peroxy esters such as 5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate; and 2,2'-azobisisobutyronitrile, 2,2'-azobis (2). , 4-Dimethylvaleronitrile), azo compounds such as 2,2'-azobis (4-methoxy-2'-dimethylvaleronitrile) and the like.

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

(MA-C) component: Cationic polymerizable compound (MA-C) component is crosslinked by reacting with a cationic polymerization initiator ((MB-C-L) component, (MB-C-H) component, etc.). It is a compound. The (MA-C) component means a compound having no radically polymerizable group that reacts with a radical, and the (MA-C) component is not included in the (MA-R) component. Examples of the (MA-C) component include an epoxy compound, an oxetane compound, an alicyclic epoxy compound and the like. The (MA-C) component may contain at least one selected from the group consisting of, for example, an oxetane compound and an alicyclic epoxy compound from the viewpoint of further improving the effect of reducing the connection resistance and improving the connection reliability. It may contain an alicyclic epoxy compound. The (MA-C) component may be used alone or in combination of two or more.

Examples of the epoxy compound include a bisphenol type epoxy resin derived from epichlorohydrin and a bisphenol compound such as bisphenol A, bisphenol F or bisphenol AD; an epoxy derived from epichlorohydrin and a novolak resin such as phenol novolac or cresol novolak. Novolak resin; various epoxy compounds having two or more glycidyl groups in one molecule such as glycidylamine, glycidyl ether, biphenyl, and alicyclic type can be mentioned. These may use one kind of compound alone or may use a plurality of compounds in combination.

The oxetane compound can be used without particular limitation as long as it has an oxetaneyl group and does not have a radically polymerizable group. Commercially available oxetane compounds include, for example, ETERNCOLL OXBP (trade name, manufactured by Ube Kosan Co., Ltd.), OXSQ, OXT-121, OXT-221, OXT-101, OXT-212 (trade name, manufactured by Toagosei Corporation). And so on. These may use one kind of compound alone or may use a plurality of compounds in combination.

The alicyclic epoxy compound can be used without particular limitation as long as it is a compound having an alicyclic epoxy group (for example, an epoxycyclohexyl group) and no radical polymerizable group. Examples of commercially available alicyclic epoxy compounds include CEL8010, CEL2021P, and CEL2081 (trade name, manufactured by Daicel Corporation). These may use one kind of compound alone or may use a plurality of compounds in combination.

(MB-CL) component: Photocationic polymerization initiator (MB-CL) component is light containing a wavelength in the range of 150 to 750 nm, preferably light containing a wavelength in the range of 254 to 405 nm. More preferably, it is a polymerization initiator that generates a substance that initiates cationic polymerization by irradiation with light having a wavelength of 365 nm (for example, ultraviolet light). The (MB-C-L) component may act as the (MB-C-H) component described later.

(MB-C-L) is, for example, BF _4- ^, BR _4- ⁽ R indicates a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups ⁾ , PF _6- ,. Examples thereof include onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts and anilinium salts having anions such as SbF ₆ ⁻ and AsF ₆ ⁻ . These may be used individually by 1 type, and may be used in combination of a plurality of types.

Commercially available products of the (MB-C-L) component include, for example, CPI-100P, CPI-110P, CPI-101A, CPI-200K, CPI-210S (all manufactured by Sun Appro Co., Ltd.), UVI-6990, UVI-. 6992, UVI-6976 (all manufactured by Dow Chemical Japan Co., Ltd.), SP-150, SP-152, SP-170, SP-172, SP-300 (all manufactured by ADEKA Corporation) and the like can be mentioned.

The content of the (MB-C-L) component is 100 parts by mass of the (MA-C) component from the viewpoint of ensuring the formability and curability of the adhesive film for forming the first adhesive layer. On the other hand, it 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.

(MB-CH) component: Thermal cationic polymerization initiator (MB-CH) component is a polymerization initiator that generates a substance that initiates cationic polymerization by heat (for example, 40 to 150 ° C.). The (MB-C-H) component may act as the above-mentioned (MB-C-L) component.

The (MB-C—H) component is similarly substituted with, for example, BF _4- ^, BR _4- ⁽ R is replaced with 2 or more fluorine atoms or 2 or more trifluoromethyl groups) in the same manner as the (MB-C—L) component. ), PF _6- ^, SbF _6- ^, AsF _6- , ^and other onium salts such as sulfonium salt, phosphonium salt, ammonium salt, diazonium salt, iodonium salt, anilinium salt, etc. Be done. These may be used individually by 1 type, and may be used in combination of a plurality of types.

Commercially available products of the (MB-CH) component include, for example, CP-66, CP-77 (all 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 Corporation), PI-2074 (Rhodia Japan Co., Ltd.) and the like.

The content of the (MB-C-H) component is 100 parts by mass of the (MA-C) component from the viewpoint of ensuring the formability and curability of the adhesive film for forming the first adhesive layer. On the other hand, it 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.

The content of the cured product (component (B)) of the component (B) is 1% by mass or more and 5% by mass or more based on the total mass of the first adhesive layer from the viewpoint of suppressing the flow of conductive particles. , Or 10% by mass or more. The content of the cured product of the component (B) is 50% by mass or less, 40% by mass or less, or 30% by mass based on the total mass of the first adhesive layer from the viewpoint of developing low resistance in low-pressure mounting. It may be as follows. When the content of the cured product of the component (B) is in the above range, the effect of the present disclosure tends to be remarkably exhibited. The content of the component (B) in the composition or the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

Component (C): Thermosetting resin component The component (C) is not particularly limited as long as it is a thermosetting resin component, but is the same as the above-mentioned resin component having radical curability ((MA-R) component). (Combination with (MB-RH) component), and the above-mentioned resin component having cation curability (combination of (MA-C) component and (MB-CH) component). May be good. The component (C) may be a resin component having cationic curability (combination of (MA-C) component and (MB-C-H) component).

The (MA-R) component, the (MB-RH) component, the (MA-C) component, and the (MB-CH) component used in the (C) component are used in the (B) component. Since it is the same as the (MA-R) component, the (MB-RH) component, the (MA-C) component, and the (MB-CH) component, detailed description thereof will be omitted here. Further, the content of the (MB-RH) component with respect to the (MA-R) component in the component (C) and the content of the (MB-CH) component with respect to the (MA-C) component are the components (B). It may be the same as the range in the case of.

The first thermosetting resin component and the second thermosetting resin component mean the thermosetting resin components contained in the first adhesive layer and the second adhesive layer, respectively. The components contained in the first thermosetting resin component and the second thermosetting resin component (for example, (MA-R) component, (MB-RH) component, (MA-C) component, (MB-). The types, combinations, and contents of CH) components, etc.) may be the same or different from each other.

The content of the component (C) is 3% 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. It may be 5% by mass or more, 10% by mass or more, or 15% by mass or more. The content of the component (C) is 70% by mass or less based on the total mass of the first adhesive layer from the viewpoint of ensuring the formability of the adhesive film for forming the first adhesive layer. It may be 60% by mass or less, 50% by mass or less, or 40% by mass or less. When the content of the component (C) is in the above range, the effect of the present disclosure tends to be remarkably exhibited. The content of the component (C) in the composition or the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

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

Examples of the component (D) include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylic rubber, epoxy resin (solid at 25 ° C.) and the like. These may be used individually by 1 type, and may be used in combination of a plurality of types. By further containing the component (D) in the composition containing the component (A), the component (B), and the component (C), the composition layer (further, the first adhesive layer 1) from the composition. Can be easily formed. Among these, the component (D) may be, for example, a phenoxy resin.

The content of the 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, 60% by mass, based on the total mass of the first adhesive layer. Hereinafter, it may be 50% by mass or less, 40% by mass or less, or 30% by mass or less. The content of the component (D) in the composition or the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

Examples of the component (E) include non-conductive fillers (for example, non-conductive particles). The component (E) may be either an inorganic filler or an organic filler. Examples of the inorganic filler include metal oxide fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles; and inorganic fine particles such as metal nitride fine particles. Examples of the organic filler include organic fine particles such as silicone fine particles, methacrylate / butadiene / styrene fine particles, acrylic / silicone fine particles, polyamide fine particles, and polyimide fine particles. These may be used individually by 1 type, and may be used in combination of a plurality of types. The component (E) may be, for example, silica fine particles. The content of the component (E) may be 0.1 to 10% by mass based on the total mass of the first adhesive layer. The content of the component (E) in the composition or the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

Examples of the component (F) include a silane coupling agent having an organic functional group such as a (meth) acryloyl group, a mercapto group, an amino group, an imidazole group and an epoxy group, a silane compound such as tetraalkoxysilane, and a tetraalkoxy titanate derivative. , Polydialkyl titanate derivatives and the like. These may be used individually by 1 type, and may be used in combination of a plurality of types. When the first adhesive layer 1 contains the component (F), the adhesiveness can be further improved. The component (F) may be, for example, a silane coupling agent. The content of the component (F) may be 0.1 to 10% by mass based on the total mass of the first adhesive layer. The content of the component (F) in the composition or the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

[Other additives]
The first adhesive layer 1 may further contain other additives such as a softening agent, an accelerator, a deterioration inhibitor, a coloring agent, a flame retardant, and a thixotropic agent. The content of the 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 the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

The thickness d1 of the first adhesive layer 1 may be, for example, 5 μm or less. The thickness d1 of the first adhesive layer 1 may be 4.5 μm or less or 4.0 μm or less. When the thickness d1 of the first adhesive layer 1 is 5 μm or less, conductive particles at the time of circuit connection can be captured more efficiently. 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 is determined by, for example, sandwiching an adhesive film between two sheets of glass (thickness: about 1 mm) and bisphenol A type epoxy resin (trade name: JER811, Mitsubishi Chemical Co., Ltd.). (Manufactured by) 100 g and a curing agent (trade name: Epomount Hardener, manufactured by Refine Tech Co., Ltd.) after casting with a resin composition, the cross section is polished using a polishing machine, and a scanning electron microscope (SEM) is performed. , Product name: SU-8000, manufactured by Hitachi High-Tech Science Co., Ltd.). Further, as shown in FIG. 1, when a part 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 first The first adhesive layer 1 and the second adhesive layer 2 located at the separated portions of the adjacent

conductive particles

4 and 4 from the surface 2a of the adhesive layer 1 opposite to the second adhesive layer 2 side. The distance to the boundary S with and (the distance indicated by d1 in FIG. 1) is the thickness of the first adhesive layer 1, and the exposed portion of the conductive particles 4 is included in the thickness of the first adhesive layer 1. I can't. The length of the exposed portion of the conductive particles 4 may be, for example, 0.1 μm or more, and may be 5 μm or less.

<Second adhesive layer>
The second adhesive layer 2 contains the component (C). The (MA-R) component, the (MB-RH) component, and the (MA-C) component used in the (C) component (that is, the second thermosetting resin component) in the second adhesive layer 2. , And the (MB-CH) component are the (MA-R) components, (MB-R) used in the (C) component in the first adhesive layer 1 (that is, the first thermosetting resin component). Since it is the same as the RH) component, the (MA-C) component, and the (MB-CH) component, detailed description thereof will be omitted here. The second thermosetting resin component may be the same as or different from the first thermosetting resin component. The second thermosetting resin component may be a combination of the (MA-C) component and the (MB-CH) component.

The content of the component (C) is 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. May be. The content of the component (C) is 70% by mass or less and 60% by mass or less based on the total mass of the second adhesive layer from the viewpoint of preventing the resin seepage problem in the reel, which is one aspect of the supply form. , 50% by mass or less, or 40% by mass or less.

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

The content of the component (D) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, and is 80% by mass or less and 60% by mass, based on the total mass of the second adhesive layer. It may be less than or equal to 40% by mass or less.

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

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

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

The thickness d2 of the second adhesive layer 2 may be appropriately set according to the height of the electrodes of the circuit member to be adhered. The thickness d2 of the second adhesive layer 2 is 5 μm or more or 7 μm or more from the viewpoint that the space between the electrodes can be sufficiently filled to seal the electrodes and better connection reliability can be obtained. It may be 20 μm or less or 15 μm or less. The thickness d2 of the second adhesive layer 2 can be obtained, for example, by the same method as the method for measuring the thickness d1 of the first adhesive layer 1. Further, when a part 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 first in the second adhesive layer 2 The distance from the surface 3a on the side opposite to the adhesive layer 1 side to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 located at the separated portions of the adjacent conductive particles 4 and 4 ( The distance (d2) in FIG. 1 is the thickness of the second adhesive layer 2.

The thickness of the adhesive film 10 (the total thickness of all the layers constituting the adhesive film 10, in FIG. 1, the thickness d1 of the first adhesive layer 1 and the thickness of the second adhesive layer 2). The total of d2) may be, for example, 5 μm or more or 8 μm or more, and may be 30 μm or less or 20 μm or less.

The first adhesive layer 1 of the adhesive film 10 is placed on a glass substrate having indium tin oxide (ITO) wiring at a temperature of 60 ° C., an area-converted pressure of the first adhesive layer 1 of 1 MPa, and a time of 1 second. The peel strength between the glass substrate and the first adhesive layer 1 at 40 ° C. after the glass substrate and the first adhesive layer 1 after being pasted is 20 to 60 N / m. The peel strength is a peel strength measured at a peel angle of 90 ° and a peel speed of 50 mm / min. When the peel strength is 60 N / m or less, the hardness of the resin is sufficient from the viewpoint of the fluidity of the resin, so that the fluidity of the resin at the time of mounting becomes small, and as a result, the capture rate of conductive particles is reduced. Can be improved. On the other hand, when the peel strength exceeds 60 N / m, the hardness of the resin is too soft from the viewpoint of the fluidity of the resin, so that the fluidity of the resin at the time of mounting is large and the capture rate of conductive particles tends to be insufficient. be. When the peel strength is 20 N / m or more, the hardness of the resin is sufficient from the viewpoint of the fluidity of the resin, so that the resin in the adhesive at the time of mounting is sufficiently eliminated, and as a result, the connection is made. It is possible to reduce the 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 the fluidity of the resin, so that the resin in the adhesive at the time of mounting is not sufficiently eliminated and the connection resistance is increased. It tends to rise. Further, when the fluidity of the resin at the time of mounting is large, the conductive particles are easily connected and the insulating property tends to be deteriorated. When the peel strength is 20 to 60 N / m, the fluidity of the resin at the time of mounting tends to be appropriate, and the insulating property tends to be good. Further, when the peel strength is 20 N / m or more, preferably 20 to 60 N / m, the transferability to the glass substrate is 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 be 55 N / m or less or 50 N / m or less.

The peel strength can be obtained by, for example, the following method. First, a glass substrate having ITO wiring (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: Prepare 0.2 μm, the number of ITO wirings: 28, and the space between ITO wirings: 300 μm). Next, the adhesive film is cut out to a size of 2 mm × 23 mm, and the first adhesive layer of the cut out adhesive film is arranged on the glass substrate having the ITO wiring so as to be perpendicular to the ITO wiring. Then, the adhesive film is attached by a thermocompression bonding machine under the conditions of a temperature of 60 ° C., an area conversion pressure of the first adhesive layer of 1 MPa, and a time of 1 second to obtain a laminate (see FIG. 4). Next, the PET film of the second adhesive film (second adhesive layer) is peeled off, and a polyimide tape cut out to a size of 1.8 mm × 35 mm is attached onto the second adhesive layer to prepare a sample for measurement. obtain. The glass substrate side of the measurement sample is placed on a hot plate set at 40 ° C., the tip of the polyimide tape is set in a tensile strength measuring device (Tensilon), and the glass substrate is fixed horizontally. Next, by pulling the attached polyimide tape under the conditions of a peeling angle of 90 ° and a peeling speed of 50 mm / min, the peeling strength between the glass substrate after the sticking and the first adhesive layer 1 at 40 ° C. is obtained. be able to.

The peel strength of the adhesive film 10 tends to fluctuate depending on the first adhesive layer 1. The peel strength of the adhesive film 10 can be adjusted, for example, by adjusting the type, content, and the like of the constituent components contained in the first adhesive layer 1. More specifically, by changing the content of the liquid component as the component (B) and the component (C), changing the glass transition point (Tg) of the component (D), changing the content of the component (E), and the like. It can be carried out.

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

The flow rate of the conductive particles can be obtained by the following method. The adhesive film 10 is punched to a diameter of 1 mm using a trepanning device to prepare a sample. The surface of the punched sample on the first adhesive film (first adhesive layer) side was heated and pressed for 1 second under the conditions of a maximum ultimate temperature of 90 ° C. and a film area conversion pressure of 1 MPa, and attached to the cover glass. This is used as a test body (test body before crimping) for measuring the area of the first adhesive layer before crimping. Next, the PET film on the second adhesive film (second adhesive layer) side is peeled off, and then the cover glass is placed. After that, the film is heated and pressurized for 5 seconds under the conditions of a maximum ultimate temperature of 170 ° C. and a film area conversion pressure of 80 MPa to attach a second adhesive film (second adhesive layer) and a cover glass, and the pressure is applied. A test piece (test piece after crimping) for measuring the area of the first adhesive layer. The area of the first adhesive layer of the test piece before crimping and the area of the first adhesive layer of the test piece after crimping can be measured with a microscope, and the flow rate of the conductive particles can be calculated from the following formula. can.
Flow rate of conductive particles (%) = (Area of first adhesive layer of test piece after crimping / Area of first adhesive layer of test piece before crimping) × 100

The flow rate of the conductive particles can be adjusted by adjusting the type, content, etc. of the constituent components contained in the first adhesive layer 1. More specifically, by adjusting the curing rate of the first adhesive layer 1, the first adhesive layer having the flow rate of the conductive particles in the above range can be obtained.

In the adhesive film 10, the conductive particles 4 are dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 is an anisotropically conductive adhesive film having an anisotropic conductivity. The adhesive film 10 is interposed between the first circuit member having the first electrode and the second circuit member having the second electrode, and heats the first circuit member and the second circuit member. It is crimped and used to electrically connect the first electrode and the second electrode to each other.

According to the adhesive film 10, it is possible to improve the capture rate of conductive particles between the facing electrodes of the circuit connection structure and reduce the connection resistance.

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

The adhesive film may be composed of, for example, two layers of a first adhesive layer and a second adhesive layer, and the two layers of the first adhesive layer and the second adhesive layer may be formed. It may be composed of three or more layers including. The adhesive film may be configured to further include, for example, a third adhesive layer provided on the opposite side of the first adhesive layer from the second adhesive layer.

The third adhesive layer contains the component (C). The (MA-R) component, the (MB-RH) component, and the (MA-C) component used in the (C) component (that is, the third thermosetting resin component) in the third adhesive layer. And the (MB-C-H) component are the (MA-R) component, (MB-R) used in the (C) component (that is, the first thermosetting resin component) in the first adhesive layer 1. Since it is the same as the —H) component, the (MA—C) component, and the (MB—C—H) component, detailed description thereof will be omitted here. The third thermosetting resin component may be the same as or different from the first thermosetting resin component. The third thermosetting resin component may be the same as or different from the second thermosetting resin component.

The content of the component (C) is 5% by mass or more, 10% by mass or more, and 15% by mass or more based on the total mass of the third adhesive layer from the viewpoint of imparting good transferability and peeling resistance. , Or 20% by mass or more. The content of the component (C) is 70% by mass or less based on the total mass of the third adhesive layer from the viewpoint of imparting good half-cut property and blocking resistance (suppression of resin seepage of the reel). It may be 60% by mass or less, 50% by mass or less, or 40% by mass or less.

The third adhesive layer may further contain other components and other additives in the first adhesive layer 1. Preferred embodiments of the other components and other additives are the same as the preferred embodiments of the first adhesive layer 1.

The content of the component (D) may be 10% by mass or more, 20% by mass or more, or 30% by mass or more, and is 80% by mass or less and 70% by mass, based on the total mass of the third adhesive layer. It may be less than or equal to 60% by mass or less.

The content of the component (E) may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, and is 50% by mass or less and 40% by mass, based on the total mass of the third adhesive layer. It may be less than or equal to 30% by mass or less.

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

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

The thickness of the third adhesive layer may be appropriately set according to the minimum melt viscosity of the adhesive film, the height of the electrodes of the circuit members to be adhered, and the like. The thickness of the third adhesive layer is preferably smaller than the thickness d2 of the second adhesive layer 2. The thickness of the third adhesive layer may be 0.2 μm or more from the viewpoint that the space between the electrodes can be sufficiently filled to seal the electrodes and better connection reliability can be obtained. , 3.0 μm or less. The thickness of the third adhesive layer can be obtained, for example, by the same method as the method for measuring the thickness d1 of the first adhesive layer 1.

Further, the circuit connection adhesive film of the above embodiment is an anisotropic conductive adhesive film having anisotropic conductivity, but the circuit connection adhesive film is a conductive adhesive having no anisotropic conductivity. It may be a film.

<Manufacturing method of adhesive film for circuit connection>
The method for producing an adhesive film for circuit connection according to one embodiment is, for example, a composition comprising a composition containing (A) component, (B) component, and (C) component (first thermosetting resin component). The step (first step) of curing the component (B) on the material layer to form the first adhesive layer, and the component (C) component (second heat) on the first adhesive layer. A step (second step) of laminating a second adhesive layer containing a curable resin component) is provided. In the manufacturing method, a third adhesive layer containing a component (C) (third thermosetting resin component) is placed on a layer of the first adhesive layer opposite to the second adhesive layer. May be further provided with a step of laminating (third step).

In the first step, for example, a composition containing (A) component, (B) component, and (C) component, and other components and other additives added as needed are organically prepared. A varnish composition is prepared by dissolving or dispersing by stirring and mixing in a solvent, kneading and the like. Then, the varnish composition is applied onto the demolding-treated substrate using a knife coater, roll coater, applicator, comma coater, die coater, etc., and then the organic solvent is volatilized by heating to form the substrate. Form a composition layer composed of the composition. At this time, the thickness of the finally obtained first adhesive layer (first adhesive film) can be adjusted by adjusting the coating amount of the varnish composition. Subsequently, the component (B) in the composition layer is cured by light, heat, humidity, etc. (preferably light or heat, more preferably light) with respect to the composition layer made of the composition, and the component (B) in the composition layer is cured on the substrate. A first adhesive layer is formed on the surface. The first adhesive layer can be said to be the first adhesive film.

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 an organic solvent include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate and the like. These organic solvents can be used alone or in combination of two or more. Stirring and mixing or kneading in the preparation of the varnish composition can be carried out by using, for example, a stirrer, a raider, a three-roll, a ball mill, a bead mill, a homodisper or the like.

The base material is not particularly limited as long as it has heat resistance that can withstand the heating conditions when volatilizing the organic solvent. Examples of such a substrate include stretched polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polyvinylidene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, and the like. A substrate (for example, a film) made of an ethylene / vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, a synthetic rubber system, a liquid crystal polymer or the like can be used.

The heating conditions for volatilizing the organic solvent from the varnish composition applied to the base material can be appropriately set according to the organic solvent to be used and the like. The heating conditions may be, for example, 40 to 120 ° C. for 0.1 to 10 minutes.

When light is used in the curing step, it is preferable to use irradiation light (for example, ultraviolet light) having a wavelength in the range of 150 to 750 nm for light irradiation. Light irradiation can be performed using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, or the like. The integrated light amount of light irradiation can be appropriately set, but may be, for example, 500 to 3000 mJ / cm ² .

The second step is a step of laminating the second adhesive layer on the first adhesive layer. The second step is the same as the first step except that, for example, the component (C) and other components and other additives added as needed are used and no light irradiation is performed. A second adhesive layer is formed on the substrate to obtain a second adhesive film. Next, the second adhesive layer can be laminated on the first adhesive layer by adhering the first adhesive film and the second adhesive film. Further, in the second step, for example, a varnish composition obtained by using the component (C) and other components and other additives added as needed is applied onto the first adhesive layer. The second adhesive layer can also be laminated on the first adhesive layer by volatilizing the organic solvent.

Examples of the method of adhering the first adhesive film and the second adhesive film include a method of heat pressing, roll laminating, vacuum laminating and the like. Lamination can be performed, for example, under temperature conditions of 0 to 80 ° C.

The third step is a step of laminating the third adhesive layer on the layer of the first adhesive layer opposite to the second adhesive layer. In the third step, for example, first, in the same manner as in the second step, a third adhesive layer is formed on the substrate to obtain a third adhesive film. Next, by adhering the third adhesive film to the side of the first adhesive film opposite to the second adhesive film, the side of the first adhesive layer opposite to the second adhesive layer A third adhesive layer can be laminated on the layer of. Further, in the third step, for example, in the same manner as in the second step, the varnish composition is applied onto the layer of the first adhesive layer opposite to the second adhesive layer, and an organic solvent is applied. The second adhesive layer can be laminated on the first adhesive layer by volatilizing the above. The method of bonding and the conditions thereof are the same as in the second step.

<Circuit connection structure and its manufacturing method>
Hereinafter, 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 will be described.

FIG. 2 is a schematic cross-sectional view showing an embodiment of a circuit connection structure. As shown in FIG. 2, the circuit connection structure 20 includes a first circuit member 13 having a first electrode 12 formed on a main surface 11a of the first circuit board 11 and the first circuit board 11. , A second circuit member 16 having a second electrode 15 formed on the main surface 14a of the second circuit board 14 and the second circuit board 14, and the first circuit member 13 and the second circuit member. It is arranged between 16 and includes a circuit connection portion 17 that electrically connects the first electrode 12 and the second electrode 15 to each other.

The first circuit member 13 and the second circuit member 16 may be the same or different from each other. The first circuit member 13 and the second circuit member 16 are a glass substrate or a plastic substrate on which a circuit electrode is formed; a printed wiring board; a ceramic wiring board; a flexible wiring board; an IC chip such as a drive IC, or the like. It's okay. The first circuit board 11 and the second circuit board 14 may be formed of an inorganic substance such as semiconductor, glass, or ceramic, an organic substance such as polyimide or polycarbonate, or a composite such as glass / epoxy. The first circuit board 11 may be a glass substrate. The first circuit member 13 may be, for example, a glass substrate on which a circuit electrode is formed, and the second circuit member 16 may be, for example, an IC chip such as a drive IC.

The first electrode 12 and the second electrode 15 are gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, titanium and other metals, indium tin oxide (ITO), and the like. It may be an electrode containing an oxide such as indium zinc oxide (IZO) or indium gallium zinc oxide (IGZO). The first electrode 12 and the second electrode 15 may be electrodes formed by laminating two or more of these metals, oxides, and the like. The electrode formed by stacking two or more types may have two or more layers, and may have three or more layers. When the first circuit member 13 is a plastic substrate, the first electrode 12 may be an electrode having a titanium layer on the 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. In FIG. 2, the first electrode 12 is a circuit electrode and the second electrode 15 is a bump electrode.

The circuit connection portion 17 contains a cured product of the above-mentioned adhesive film 10. The circuit connection portion 17 may be made of a cured product of the adhesive film 10 described above. The circuit connection portion 17 is located, for example, on the side of the first circuit member 13 in the direction in which the first circuit member 13 and the second circuit member 16 face each other (hereinafter referred to as “opposite direction”), and the above-mentioned first circuit member 17 is located. It is located on the side of the first region 18 composed of the cured product of the component (B) and the cured product of the component (C) other than the conductive particles 4 in the adhesive layer of No. 1 and the second circuit member 16 in the opposite direction. The first electrode 12 and the first electrode 12 are interposed between the second region 19 made of a cured product such as the component (C) in the second adhesive layer and at least the first electrode 12 and the second electrode 15. It has conductive particles 4 that electrically connect the second electrodes 15 to each other. As shown in FIG. 2, the circuit connection portion 17 does not have to have two distinct regions between the first region 18 and the second region 19, and the first adhesive layer The cured product derived from the above and the cured product derived from the second adhesive layer may be mixed to form one region.

The circuit connection structure is, for example, a flexible organic electric field light emitting color display (organic EL display) in which a plastic substrate on which organic EL elements are regularly arranged and a drive circuit element which is a driver for displaying an image are connected. Examples thereof include a touch panel in which a plastic substrate on which organic EL elements are regularly arranged and a position input element such as a touch pad are connected. The circuit connection structure can be applied to various monitors such as smart phones, tablets, televisions, vehicle navigation systems, wearable terminals, furniture; home appliances; daily necessities and the like.

FIG. 3 is a schematic cross-sectional view showing an embodiment of a method for manufacturing a circuit connection structure. 3 (a) and 3 (b) are schematic cross-sectional views showing each process. As shown in FIG. 3, a method of manufacturing the circuit connection structure 20 is performed between a first circuit member 13 having a first electrode 12 and a second circuit member 16 having a second electrode 15. The above-mentioned adhesive film 10 is interposed, the first circuit member 13 and the second circuit member 16 are thermocompression bonded, and the first electrode 12 and the second electrode 15 are electrically connected to each other. ..

Specifically, as shown in FIG. 3A, first, a first circuit including a first electrode 12 formed on a main surface 11a of a first circuit board 11 and a first circuit board 11. A member 13 and a second circuit member 16 provided with a second electrode 15 formed on the main surface 14a of the second circuit board 14 and the second circuit board 14 are prepared.

Next, the first circuit member 13 and the second circuit member 16 are arranged so that the first electrode 12 and the second electrode 15 face each other, and the first circuit member 13 and the second circuit member 12 are arranged. The adhesive film 10 is placed between the 16 and 16. For example, as shown in FIG. 3A, the adhesive film 10 is laminated on the first circuit member 13 so that the first adhesive layer 1 side faces the main surface 11a of the first circuit board 11. do. Next, the adhesive film 10 is laminated so that the first electrode 12 on the first circuit board 11 and the second electrode 15 on the second circuit board 14 face each other. The second circuit member 16 is arranged on the circuit member 13.

Then, as shown in FIG. 3B, while heating the first circuit member 13, the adhesive film 10, and the second circuit member 16, the first circuit member 13 and the second circuit member 16 By pressurizing in the thickness direction, the first circuit member 13 and the second circuit member 16 are thermocompression bonded to each other. At this time, as shown by an arrow in FIG. 3B, since the second adhesive layer 2 has a flowable uncured thermosetting component, the second electrodes 15 are connected to each other. It flows so as to fill the voids and is cured by the above 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 adhered to each other. The circuit connection structure 20 shown in 2 can be obtained. In the method for manufacturing the circuit connection structure 20 of the present embodiment, it can be said that a part of the first adhesive layer 1 is cured by light, heat, moisture, or the like, so that the first adhesive layer 1 is the heat. Since it hardly flows during crimping and the conductive particles are efficiently captured between the facing electrodes, the connection resistance between the facing first electrode 12 and the second electrode 15 is reduced. Further, when the thickness of the first adhesive layer is 5 μm or less, the conductive particles at the time of circuit connection tend to be captured more efficiently.

The heating temperature for thermocompression bonding can be set as appropriate, but may be, for example, 50 to 190 ° C. The pressurization is not particularly limited as long as it does not damage the adherend, but in the case of COG mounting, the area conversion pressure at the bump electrode may be, for example, 10 to 100 MPa. These heating and pressurizing times may be in the range of 0.5 to 120 seconds. Further, in the case of COP (chip on plastic) mounting, for example, the area conversion pressure at the bump electrode may be 0.1 to 50 MPa.

Hereinafter, this disclosure will be described more specifically with reference to examples. However, the present disclosure is not limited to these examples.

[Preparation of First Adhesive Layer and Second Adhesive Layer]
In the preparation of the first adhesive layer and the second adhesive layer, the materials shown below were used.

(A) Component: Conductive particles Conductive particles A-1: Insulation-coated conductive particles having an average particle size of 3.2 μm, in which the surface of a plastic core is Ni-plated and the outermost surface is insulated and coated, are used.

(B) component: curable resin component and (C) component: thermosetting resin component (B) component and (C) component are the following (MA) polymerizable compound and (MB) polymerization initiation as shown in Table 1. The agent was selected and used. By combining the (MA-R) radically polymerizable compound and the (MB-RL) photoradical polymerization initiator, it can act as a photocurable resin component. On the other hand, by combining the (MA-R) radically polymerizable compound and the (MB-RH) thermal radical polymerization initiator, it can act as a thermosetting component. Further, by combining the (MA-C) cationically polymerizable compound and the (MB-C-L) photocationic polymerization initiator, it can act as a photocurable component. On the other hand, by combining the (MA-C) cationically polymerizable compound and the (MB-C-H) thermally cationic polymerization initiator, it can act as a thermosetting component.

(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 KK)
Radical Polymerizable Compound MA-R-3: DCP-A (Dimethylol-Tricyclodecane Diacrylate (bifunctional), manufactured by Kyoeisha Chemical Co., Ltd.)
(MA-C) Cationicly polymerizable compound MA-C-1: CEL2021P (3', 4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (aliphatic epoxy compound), Daicel Co., Ltd. Made by Co., Ltd.)
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, BASF Made by the company)
(MB-RH) Thermal Radical Polymerization Initiator MB-RH-1: Perhexa 25O (2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, Made by NOF Corporation)
(MB-C-L) Photocationic Polymerization Initiator Photocationic Polymerization Initiator MB-C-L-1: CPI-101A (Triarylsulfonium SbF ₆ Salt, manufactured by San-Apro Co., Ltd.)
(MB-C-H) Thermal Cationic Polymerization Initiator MB-C-H-1: SI-60 (Aromatic Sulfonium / SbF ₆ Salt, manufactured by Sanshin Chemical Industry Co., Ltd.)

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

(E) Component: Filler Filler E-1: SE2050 (Silica fine particles, manufactured by Admatex Co., Ltd., average particle size: 0.5 μm)

<Preparation of the first adhesive film (first adhesive layer)>
A composition was obtained by mixing the materials shown in Table 1 with the composition ratio shown in Table 1 (the numerical value in Table 1 means the amount of solid content). Then, on a PET (polyethylene terephthalate) film (manufactured by Mitsui Chemicals Tohcello Co., Ltd.) with a thickness of 38 μm, the film was applied so that the thickness after drying was 3 μm and the number of conductive particles was 22,000 / mm ² . The composition layers 1a to 1e composed of the composition containing each component were obtained by drying at 60 ° C./1 minute. The composition layers 1a, 1b, and 1e were irradiated with ultraviolet rays (irradiation amount: 1500 mJ / cm ² ) using an ultraviolet irradiation device to obtain first adhesive films 1A, 1B, and 1E. The composition layer 1c was further dried in an oven at 70 ° C./4 min to obtain a first adhesive film 1C. The composition layer 1d was used as it was as the first adhesive film 1D.

<Preparation of second adhesive film (second adhesive layer)>
After mixing the materials shown in Table 2 at the composition ratio shown in Table 2 (the numerical value in Table 2 means the amount of solid content), on a PET (polyethylene terephthalate) film (manufactured by Toyobo Film Solution Co., Ltd.) having a thickness of 38 μm. The second adhesive film 2A was obtained by coating the film so that the thickness after drying was 12 μm and drying in an oven at 60 ° C./3 minutes.

(Examples 1 to 3 and Comparative Examples 1 and 2)
[Preparation of adhesive film]
Using the first adhesive film and the second adhesive film prepared above, an adhesive film having the constitution shown in Table 3 was prepared. Regarding the adhesive films of Examples 1 to 3 and Comparative Examples 1 and 2, the first adhesive film is bonded to the second adhesive film while applying a temperature of 50 to 60 ° C., and the configurations shown in Table 3 are attached. Adhesive film was prepared.

[Evaluation of transferability]
The adhesive films of Examples 1 to 3 and Comparative Examples 1 and 2 were cut into 2.5 mm × 25 mm, and the surface on the side of the first adhesive film (first adhesive layer) was brought to the glass substrate at a maximum temperature of 90. Temporarily crimped by heating and pressurizing for 1 second under the conditions of ° C. and an area conversion pressure of 1 MPa at the bump electrode. After the temporary crimping, the PET film of the second adhesive film (second adhesive layer) was pinched with tweezers and peeled off from the second adhesive layer. At this time, the case where the adhesive film is attached to the glass substrate is evaluated as "A" as having excellent transferability, and the case where the adhesive film floats from the glass substrate or is completely peeled off from the glass substrate. It was evaluated as "B". The results are shown in Table 3.

[Measurement of peel strength]
First, a glass substrate having ITO wiring (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) were prepared. The adhesive films of Examples 1 to 3 and Comparative Examples 1 and 2 are cut out to a size of 2 mm × 23 mm, and the first adhesive film (first adhesive layer) of the cut out adhesive film is a glass substrate having ITO wiring. It was arranged on the top so as to be perpendicular to the ITO wiring. Then, the adhesive film was attached by a thermocompression bonding machine under the conditions of a temperature of 60 ° C., an area conversion pressure of the first adhesive layer of 1 MPa, and a time of 1 second to obtain a laminate. FIG. 4 is a schematic top view showing the laminated body in the peel strength measurement of the embodiment. The laminate 30 shown in FIG. 4 is arranged on a glass substrate 33 having ITO wiring (a substrate including the glass substrate 31 and the ITO wiring 32 provided on the glass substrate 31) and a glass substrate 33 having ITO wiring. It is provided with an adhesive film 10A. Next, the PET film of the second adhesive film (second adhesive layer) is peeled off, and a polyimide tape cut out to a size of 1.8 mm × 35 mm is attached onto the second adhesive layer to prepare a sample for measurement. Obtained. The glass substrate side of the measurement sample was placed on a hot plate set at 40 ° C., and the tip of the polyimide tape was set in a tensile strength measuring device (Tensilon). By fixing the glass substrate horizontally and pulling the polyimide tape in the vertical direction at a peeling speed of 50 mm / min, the peeling angle is 90 °. The peel strength in was measured. The results are shown in Table 3.

[Evaluation of connection resistance, indentation strength, and capture rate of conductive particles]
(Preparation of circuit members)
As the first circuit member, a glass substrate having ITO wiring (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 wiring: 6 μm) was prepared. As the second circuit member, an IC chip having a gold bump electrode (IC chip size: 0.9 mm × 20.3 mm, IC chip thickness: 0.3 mm, gold bump electrode size: 12 μm × 100 μm, The thickness of the gold bump electrode: 12 μm, the space between the gold bump electrodes: 24 μm) was prepared.

(Making a circuit connection structure)
The circuit connection structure was carried out using the adhesive films of Examples 1 to 3 and Comparative Examples 1 and 2. The adhesive film was cut out to a size of 2 mm × 23 mm, and the first adhesive layer of the cut out adhesive film was placed on the first circuit member so as to be in contact with the circuit electrode of the first circuit member. Using a thermocompression bonding device (BS-17U, manufactured by Ohashi Seisakusho Co., Ltd.) consisting of a stage consisting of a ceramic heater and a tool (8 mm x 50 mm), heat and pressurize for 5 seconds at 130 ° C. and 40 MPa. An adhesive film was attached to the first circuit member. Next, the PET film on the side opposite to the first circuit member of the adhesive film is peeled off, the circuit electrode of the first circuit member and the bump electrode of the second circuit member are aligned, and then the adhesive is applied. The second adhesive layer of the adhesive film is attached to the second circuit member by heating and pressurizing for 5 seconds under the conditions of the maximum measured maximum temperature of the film of 130 ° C. and the area conversion pressure of 40 MPa at the bump electrode. A connection structure was prepared.

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

(Evaluation of indentation strength)
The indentation strength of the obtained circuit connection structure was evaluated. Electrodes were observed from the glass substrate of the obtained circuit connection structure using a differential interference microscope, and indentations were observed at the portions where the ends and the center of the IC chip were connected. The observed indentations were photographed and used as image data, and the intensities were evaluated in five stages of 1, 2, 3, 4, and 5 using indentation analysis software. The larger the evaluation value, the higher the indentation strength. When the indentation strength is high, the connection stability tends to be excellent. The results are shown in Table 3.

(Evaluation of capture rate of conductive particles)
The obtained circuit connection structure was observed with a differential interference microscope, the number of conductive particles captured between the electrodes was measured, and the number of conductive particles captured between the electrodes per electrode area was calculated. At this time, 100 electrodes were observed, and the average value thereof was taken as the number of captured conductive particles between the electrodes per electrode area. The capture rate of conductive particles was calculated from the following formula. The results are shown in Table 3.
Capturing rate of conductive particles (%) = (Number of trapped conductive particles between electrodes per electrode area (pieces / mm ² ) / Number of conductive particles per unit area of adhesive film (pieces / mm ² )) x 100

[Evaluation of flow rate of conductive particles]
The adhesive films of Examples 1 to 3 and Comparative Examples 1 and 2 were punched to a diameter of 1 mm using a trepanning device to prepare a sample. The surface of the punched sample on the first adhesive film (first adhesive layer) side was heated and pressed for 1 second under the conditions of a maximum ultimate temperature of 90 ° C. and a film area conversion pressure of 1 MPa, and attached to the cover glass. This was used as a test body (test body before crimping) for measuring the area of the first adhesive layer before crimping. Next, the PET film on the second adhesive film (second adhesive layer) side was peeled off, and then the cover glass was placed. After that, the film is heated and pressurized for 5 seconds under the conditions of a maximum ultimate temperature of 170 ° C. and a film area conversion pressure of 80 MPa to attach a second adhesive film (second adhesive layer) and a cover glass, and the pressure is applied. A test body (test body after pressure bonding) for measuring the area of the first adhesive layer was used. The area of the first adhesive layer of the test piece before crimping and the area of the first adhesive layer of the test piece after crimping were measured with a microscope, and the flow rate of the conductive particles was calculated from the following formula. The results are shown in Table 3.
Flow rate of conductive particles (%) = (Area of first adhesive layer of test piece after crimping / Area of first adhesive layer of test piece before crimping) × 100

As shown in Table 3, the adhesive films of Examples 1 to 3 were excellent in all items. On the other hand, the adhesive film of Comparative Example 1 having a predetermined peel strength of more than 60 N / m did not have a sufficient capture rate of conductive particles. It is considered that this is because the hardness of the resin is too soft in terms of the fluidity of the resin. Further, the adhesive film of Comparative Example 2 having a predetermined peel strength of less than 20 N / m did not have sufficient connection resistance, and was not sufficient in terms of transferability and indentation strength. It is considered that this is because the hardness of the resin is too hard in terms of the fluidity of the resin. From these results, it was confirmed that the adhesive film of the present disclosure can improve the capture rate of conductive particles between the facing electrodes of the circuit connection structure and reduce the connection resistance.

1 ... 1st adhesive layer, 2 ... 2nd adhesive layer, 4 ... conductive particles, 5 ... adhesive component, 10 ... circuit connection adhesive film (adhesive film), 10A ... adhesive film, 11 ... 1st circuit board, 12 ... 1st electrode (circuit electrode), 13 ... 1st circuit member, 14 ... 2nd circuit board, 15 ... 2nd electrode (bump electrode), 16 ... 2nd A glass substrate having a circuit member, 17 ... circuit connection portion, 20 ... circuit connection structure, 30 ... laminate, 31 ... glass substrate, 32 ... ITO wiring, 33 ... ITO wiring.

Claims

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 provided on the first adhesive layer, and a second adhesive layer.
An adhesive film for circuit connection
The first adhesive layer of the circuit connection adhesive film is placed on a glass substrate having indium tin oxide (ITO) wiring at a temperature of 60 ° C., an area-converted pressure of the first adhesive layer of 1 MPa, and a time of 1. A circuit connection adhesive having a peeling strength of 20 to 60 N / m between the glass substrate and the first adhesive layer at 40 ° C. after being treated and pasted under the condition of seconds. the film.
The circuit connection adhesive film according to claim 1, wherein the curable resin component has photocurability.
The circuit connection adhesive film according to claim 1, wherein the curable resin component has thermosetting property.
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.
The curable resin component is cured on a layer composed of a composition containing conductive particles, a curable resin component, and a first thermosetting resin component to form a first adhesive layer. Process and
A step of providing a second adhesive layer containing a second thermosetting resin component on the first adhesive layer to obtain an adhesive film for circuit connection.
Equipped with
The first adhesive layer of the circuit connection adhesive film is placed on a glass substrate having indium tin oxide (ITO) wiring at a temperature of 60 ° C., an area-converted pressure of the first adhesive layer of 1 MPa, and a time of 1. A circuit connection adhesive having a peeling strength of 20 to 60 N / m between the glass substrate and the first adhesive layer at 40 ° C. after being treated and pasted under the condition of seconds. How to make a film.
The method for manufacturing an adhesive film for circuit connection according to claim 5, wherein the curable resin component has photocurability.
The method for manufacturing an adhesive film for circuit connection according to claim 5, wherein the curable resin component has thermosetting property.
The method for producing 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.
The circuit connection adhesive film according to any one of claims 1 to 4 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode. A method for manufacturing a circuit connection structure, comprising a step of thermally crimping the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other. ..
A first circuit member having a first electrode and
A second circuit member having a second electrode and
A circuit connection portion that is arranged 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 in which the circuit connection portion contains a cured product of the adhesive film for circuit connection according to any one of claims 1 to 4.