Adhesive film for circuit connection, circuit connection structure, and method for producing same

Abstract

The invention discloses an adhesive film for circuit connection, and a circuit connection structure and a manufacturing method thereof. The adhesive film for circuit connection is provided with: a first adhesive layer containing conductive particles, a cured product of a photocurable resin component, and a first thermosetting resin component; and a second adhesive layer provided on the first adhesive layer and containing a second thermosetting resin component. The thickness of the first adhesive layer is 5 [mu] m or less, the first thermosetting resin component and the second thermosetting resin component contain a cationically polymerizable compound and a thermal cationic polymerization initiator, and the photocurable resin component contains a radically polymerizable compound. The cationically polymerizable compound contains both an oxetane compound and an alicyclic epoxy compound.

Description

[0001] This application is a divisional application of a patent application for an invention titled "Adhesive Film for Circuit Connection, Circuit Connection Structure, and Method for Manufacturing the Same" with an application number of 202180037776.9, a filing date of June 8, 2021. Technical Field

[0002] The present invention relates to an adhesive film for circuit connection, a circuit connection structure, and a method for manufacturing the same. Background Art

[0003] Conventionally, as various display mechanisms such as televisions, PC monitors, mobile phones, and smartphones, liquid crystal display panels, organic EL panels, etc. have been used. In such display devices, from the viewpoints of fine pitch, lightweight and thin profile, etc., a so-called COG (chip on glass) package in which a driving IC is packaged on a glass substrate of a direct display panel has been adopted.

[0004] In a liquid crystal display panel adopting the COG package method, for example, semiconductor elements such as a liquid crystal driving IC are connected to a transparent substrate (glass substrate, etc.) having a plurality of transparent electrodes (ITO (indium tin oxide), etc.). As an adhesive material for connecting an electrode terminal of a semiconductor element and a transparent electrode, an anisotropic conductive adhesive film for circuit connection in which conductive particles are dispersed in an adhesive is used. For example, in the case of packaging a liquid crystal driving IC as a semiconductor element, the packaging surface of the liquid crystal driving IC has a plurality of electrode terminals corresponding to the transparent electrodes, and the liquid crystal driving IC is thermocompression bonded to the transparent substrate via an anisotropic conductive adhesive film for circuit connection, thereby connecting the electrode terminals and the transparent electrodes, and a circuit connection structure can be obtained.

[0005] In recent years, a display with a curved surface (flexible display) has been proposed. In such a flexible display, a flexible plastic substrate (polyimide substrate, etc.) is used as a substrate instead of a glass substrate, and various electronic parts such as a driving IC are also packaged on the plastic substrate. As such a packaging method, a COP (chip on plastic) package using an anisotropic conductive adhesive film for circuit connection has been studied (for example, refer to Patent Document 1).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-054288 Summary of the Invention

[0009] Technical Problem to be Solved by the Invention

[0010] In a flexible display used in an organic EL panel or the like, a polyimide substrate having a circuit electrode with a titanium layer on the outermost layer is mainly used. According to the research by the present inventors, it has been found that an oxide film exists on the surface of the circuit electrode having a titanium layer on the outermost layer, and the higher the resin fluidity of the adhesive film for circuit connection becomes, the easier it is for the connection resistance between circuits to become lower. However, a high resin fluidity means that conductive particles also easily flow, and short-circuit defects between adjacent circuits are likely to occur due to the flowing conductive particles.

[0011] On the other hand, for example, it has been studied to cure the adhesive of the adhesive film for circuit connection by heat or light to suppress the fluidity of conductive particles. However, at this time, the excludability of the resin in the adhesive also decreases, and it is speculated that the connection resistance increases.

[0012] Regarding the excludability of the resin itself, it can be tolerated in principle by encapsulation under high pressure. However, at this time, a pressure-sensitive adhesive layer such as a pressure-sensitive resin and a film such as PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) are usually disposed on the lower surface of the polyimide substrate. Together with the polyimide substrate, stress accumulates in the circuit electrode having a titanium layer on the outermost layer, cracks are generated, and defects such as circuit disconnection may occur. Therefore, when encapsulating a flexible display, it is desirable to perform encapsulation under low pressure (for example, the pressure converted to the area on the bump electrode is 0.1 to 50 MPa), and the adhesive film for circuit connection used for COP encapsulation is required to suppress the fluidity of conductive particles and the increase in connection resistance under low-pressure encapsulation.

[0013] The main object of the present invention is to provide an adhesive film for circuit connection that can improve the capture rate of conductive particles between opposing electrodes of a circuit connection structure and can reduce the connection resistance even in the case of encapsulation under low pressure.

[0014] Means for Solving the Technical Problem

[0015] One aspect of the present invention relates to an adhesive film for circuit connection. The adhesive film for circuit connection includes: a first adhesive layer containing conductive particles, a cured product of a photocurable resin component, and a first thermosetting resin component; and a second adhesive layer provided on the first adhesive layer and containing a second thermosetting resin component. The thickness of the first adhesive layer is 5 μm or less. According to such an adhesive film for circuit connection, the fluidity of the conductive particles during circuit connection can be suppressed while suppressing the decrease in resin exudation property by curing the photocurable resin component. Further, since the thickness of the first adhesive layer is 5 μm or less, the fluidity of the conductive particles during circuit connection can be further suppressed. Therefore, even in the case of encapsulation under low pressure, the capture rate of the conductive particles between the opposing electrodes of the circuit connection structure can be increased, and the connection resistance can be reduced. Such an adhesive film for circuit connection can be applied to COP encapsulation.

[0016] The first thermosetting resin component and the second thermosetting resin component may include a cationically polymerizable compound and a thermal cationic polymerization initiator, and the photocurable resin component may include a radically polymerizable compound. In this case, the first thermosetting resin component and the second thermosetting resin component have cationic curability, and the photocurable resin component has radical curability. According to the research of the present inventors, if the first thermosetting resin component and the second thermosetting resin component and the photocurable resin component are such a combination, for example, compared with the case where all the curable resin components have cationic curability, it tends to be more excellent in terms of connection resistance. As a reason for exerting such an effect, the inventors of the present invention speculate as follows. That is, it is considered that if all the curable resin components have a cationic curable component, for example, in the first adhesive layer, cationic active species may sometimes remain when forming the cured product of the photocurable resin component, and the curing reaction of the second thermosetting resin component in the second adhesive layer is caused by the cationic active species, resulting in a decrease in resin exudation property. Therefore, if the photocurable resin component has radical curability, cationic active species are not generated when forming the cured product of the photocurable resin component, so the progress of the curing reaction of the second thermosetting resin component in the second adhesive layer can be suppressed, and it is expected to suppress the decrease in resin exudation property and reduce the connection resistance.

[0017] The cationically polymerizable compound may be at least one selected from the group consisting of an oxetane compound and an alicyclic epoxy compound. The thermal cationic polymerization initiator may be a salt compound having an anion containing boron as a constituent element.

[0018] The adhesive film for circuit connection may further include a third adhesive layer provided on the side of the first adhesive layer opposite to the second adhesive layer and containing a third thermosetting resin component. The third thermosetting resin component may include a cationically polymerizable compound and a thermal cationic polymerization initiator.

[0019] Another aspect of the present invention relates to a method for manufacturing a circuit connection structure. The method for manufacturing the circuit connection structure includes the following steps: interposing the above-mentioned adhesive film for circuit connection between a first circuit component having a first electrode and a second circuit component having a second electrode, and performing thermocompression bonding on the first circuit component and the second circuit component to electrically connect the first electrode and the second electrode to each other.

[0020] Another aspect of the present invention relates to a circuit connection structure. The circuit connection structure includes: a first circuit component having a first electrode; a second circuit component having a second electrode; and a circuit connection portion disposed between the first circuit component and the second circuit component to electrically connect the first electrode and the second electrode to each other. The circuit connection portion includes a cured product of the above-mentioned adhesive film for circuit connection.

[0021] Advantages of the Invention

[0022] According to the present invention, there is disclosed an adhesive film for circuit connection, which can improve the capture rate of conductive particles between opposing electrodes of a circuit connection structure and can reduce the connection resistance even in the case of encapsulation under low pressure. Such an adhesive film for circuit connection can be applied to COP encapsulation. Further, according to the present invention, there are disclosed a circuit connection structure using such an adhesive film for circuit connection and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a schematic cross-sectional view showing an embodiment of the adhesive film for circuit connection.

[0024] Figure 2 FIG. is a schematic cross-sectional view showing an embodiment of the circuit connection structure.

[0025] Figure 3 FIG. is a schematic cross-sectional view showing an embodiment of the method for manufacturing the circuit connection structure. Figure 3 (a) and Figure 3 (b) are schematic cross-sectional views showing each step. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent parts are denoted by the same reference numerals, and repeated descriptions are omitted. In addition, the present invention is not limited to the following embodiments.

[0027] In this specification, a numerical range indicated using "~" represents a range that includes the numerical values before and after "~" as the minimum value and the maximum value, respectively. In a numerical range described stepwise in this specification, the upper limit value or the lower limit value of a certain stepwise numerical range can be replaced with the upper limit value or the lower limit value of another stepwise numerical range. Moreover, within the numerical range described in this specification, the upper limit value or the lower limit value of this numerical range can be replaced with the value shown in the examples. Furthermore, the separately described upper limit value and lower limit value can be arbitrarily combined. In the notation of the numerical range "A~B", the two end numerical values A and B are included in the numerical range as the lower limit value and the upper limit value, respectively. In this specification, for example, the description "10 or more" means "10" and "values exceeding 10", and the same applies in the case of different numerical values. Also, for example, the description "10 or less" means "10" and "values less than 10", and the same applies in the case of different numerical values. In this specification, "(meth)acrylate" means at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl" and "(meth)acrylic acid". Moreover, "A or B" can include either A or B, or can include both. Regarding the materials exemplified below, unless otherwise specified, one kind can be used alone, or two or more kinds can be used in combination. Regarding the content of each component in the composition, when there are multiple substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the multiple substances present in the composition.

[0028] [Adhesive Film for Circuit Connection]

[0029] Figure 1 It is a schematic cross-sectional view showing one embodiment of the adhesive film for circuit connection. Figure 1 The adhesive film 10 for circuit connection (hereinafter, sometimes simply referred to as "adhesive film 10") shown in includes: a first adhesive layer 1 containing conductive particles 4 and an adhesive component 5 including a cured product of a photocurable resin component and a (first) thermosetting resin component; and a second adhesive layer 2 provided on the first adhesive layer 1 and containing a (second) thermosetting resin component. In the adhesive film 10, there can be a first region formed by the first adhesive film (first adhesive layer 1) and a second region adjacent to the first region and formed by the second adhesive film (second adhesive layer 2). That is, the adhesive film 10 can also include: a first region containing conductive particles 4 and an adhesive component 5 including a cured product of a photocurable resin component and a (first) thermosetting resin component; and a second region adjacent to the first region and containing a (second) thermosetting resin component.

[0030] In the adhesive film 10, the conductive particles 4 are dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 can be an anisotropic conductive adhesive film for circuit connection (anisotropic conductive adhesive film). The adhesive film 10 can be interposed between a first circuit component having a first electrode and a second circuit component having a second electrode, and is used for thermocompression bonding the first circuit component and the second circuit component to electrically connect the first electrode and the second electrode to each other.

[0031] <First Adhesive Layer>

[0032] The first adhesive layer 1 contains a cured product of conductive particles 4 (hereinafter sometimes referred to as "(A) component"), a photocurable resin component (hereinafter sometimes referred to as "(B) component"), and a thermosetting resin component (hereinafter sometimes referred to as "(C) component"). The first adhesive layer 1 can be obtained, for example, by irradiating a composition layer made of a composition containing the (A) component, the (B) component, and the (C) component with light energy to polymerize the components contained in the (B) component and cure the (B) component. The first adhesive layer 1 contains the (A) component and an adhesive component 5 containing a cured product of the (B) component and the (C) component. The cured product of the (B) component can be a cured product obtained by completely curing the (B) component or a cured product obtained by partially curing the (B) component. The (C) component is a component that can flow during circuit connection, and is, for example, an uncured curable resin component.

[0033] (A) Component: Conductive Particles

[0034] Regarding the (A) component, as long as it is a particle having conductivity, there is no particular limitation, and it can be a metal particle composed of a metal such as Au, Ag, Pd, Ni, Cu, solder, etc., a conductive carbon particle composed of conductive carbon, etc. The (A) component can be a coated conductive particle having a core containing a non-conductive material such as glass, ceramic, plastic (polystyrene, etc.) and a coating layer containing the above metal or conductive carbon and covering the core. Among these, the (A) component preferably has a coated conductive particle having a core containing a metal particle or plastic formed of a heat-fusible metal and a coating layer containing a metal or conductive carbon and covering the core. Such a coated conductive particle can easily deform the cured product of the thermosetting resin component by heating or pressurization, so that when the electrodes are electrically connected to each other, the contact area between the electrode and the (A) component can be increased, and the conductivity between the electrodes can be further improved.

[0035] (A) component can be insulating-coated conductive particles having the above-mentioned metal particles, conductive carbon particles or coated conductive particles and an insulating layer that contains an insulating material such as resin and coats the surface of the particles. If the (A) component is insulating-coated conductive particles, even when the content of the (A) component is high, since an insulating layer is provided on the surface of the particles, the occurrence of short circuits caused by the contact of the (A) components with each other can be suppressed, and the insulation between adjacent electrode circuits can also be improved. The (A) component can be used alone one kind of the above various conductive particles or in combination of two or more kinds.

[0036] (A) The maximum particle size of the component needs to be smaller than the minimum interval of the electrodes (the shortest distance between adjacent electrodes). From the viewpoints of excellent dispersibility and conductivity, the maximum particle size of the (A) component can be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the viewpoints of excellent dispersibility and conductivity, the maximum particle size of the (A) component can be 20 μm or less, 10 μm or less, or 5 μm or less. In this specification, for any 300 (pcs) conductive particles, the particle size is measured by observation using a scanning electron microscope (SEM), and the maximum value obtained is taken as the maximum particle size of the (A) component. In addition, when the (A) component has protrusions or the like, or when the (A) component is not spherical, the particle size of the (A) component is taken as the diameter of the circle circumscribing the conductive particle in the SEM image.

[0037] (A) From the viewpoints of excellent dispersibility and conductivity, the average particle size of the component can be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the viewpoints of excellent dispersibility and conductivity, the average particle size of the (A) component can be 20 μm or less, 10 μm or less, or 5 μm or less. In this specification, for any 300 (pcs) conductive particles, the particle size is measured by observation using a scanning electron microscope (SEM), and the average value of the particle sizes obtained is taken as the average particle size.

[0038] In the first adhesive layer 1, the (A) component is preferably uniformly dispersed. From the viewpoint of obtaining a stable connection resistance, the particle density of the (A) component in the adhesive film 10 can be 100 pieces / mm 2 or more, 1000 pieces / mm 2 or more, 3000 pieces / mm 2 or more, or 5000 pieces / mm 2 or more. From the viewpoint of improving the insulation between adjacent electrodes, the particle density of the (A) component in the adhesive film 10 can be 100000 pieces / mm 2 or less, 70000 pieces / mm 2 or less, 50000 pieces / mm 230,000 pieces / mm or less 2 or less

[0039] From the viewpoint of further improving the conductivity, based on the total mass of the first adhesive layer, the content of component (A) can be 1% by mass or more, 5% by mass or more, or 10% by mass or more. From the viewpoint of easily suppressing short circuits, based on the total mass of the first adhesive layer, the content of component (A) can be 60% by mass or less, 50% by mass or less, or 40% by mass or less. If the content of component (A) is within the above range, the effects of the present invention tend to be significantly exhibited. In addition, the content of component (A) in the composition or the composition layer (based on the total mass of the composition or the composition layer) can be the same as the above range.

[0040] Component (B): a photocurable resin component

[0041] Regarding component (B), there is no particular limitation as long as it is a resin component that is cured by light irradiation. However, in the case where component (C) is a resin component having cationic curability, from the viewpoint of more excellent connection resistance, component (B) can be a resin component having radical curability. Component (B) can include, for example, a radically polymerizable compound (hereinafter, sometimes referred to as “component (B1)”) and a photo radical polymerization initiator (hereinafter, sometimes referred to as “component (B2)”). Component (B) can be a component composed of component (B1) and component (B2).

[0042] Component (B1): a radically polymerizable compound

[0043] Component (B1) is a compound that is radically polymerized by component (B2) upon irradiation with light (for example, ultraviolet light). Component (B1) can be either a monomer or a polymer (or oligomer) formed by polymerization of one or more monomers. Regarding component (B1), one type can be used alone, or multiple types can be used in combination.

[0044] Component (B1) is a compound having a radical polymerizable group that reacts by radicals. As the radical polymerizable group, for example, (meth)acryloyl, vinyl, allyl, styryl, alkenyl, alkenylene, maleimide group, etc. can be cited. From the viewpoint of easily obtaining the desired melt viscosity after polymerization, further improving the effect of reducing the connection resistance, and more excellent connection reliability, the number of radical polymerizable groups (functional groups) possessed by component (B1) can be 2 or more, and from the viewpoint of suppressing curing shrinkage during polymerization, it can be 10 or less. And, in order to maintain the balance between the crosslink density and the curing shrinkage, in addition to the compound having the number of radical polymerizable groups within the above range, a compound having the number of radical polymerizable groups outside the above range can also be used.

[0045] In terms of the view of suppressing the flow of conductive particles, for example, the component (B1) may contain a polyfunctional (two or more functional groups) (meth)acrylate. The polyfunctional (two or more functional groups) (meth)acrylate may be a bifunctional (meth)acrylate, and the bifunctional (meth)acrylate may be a bifunctional aromatic (meth)acrylate.

[0046] As polyfunctional (meth)acrylates, for example, there may be mentioned aliphatic (meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, glycerol di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, ethoxylated 2-methyl-1,3-propanediol di(meth)acrylate; aromatic (meth)acrylates such as ethoxylated bisphenol A type di(meth)acrylate, propoxylated bisphenol A type di(meth)acrylate, ethoxylated propoxylated bisphenol A type di(meth)acrylate, ethoxylated bisphenol F type di(meth)acrylate, propoxylated bisphenol F type di(meth)acrylate, ethoxylated propoxylated bisphenol F type di(meth)acrylate, ethoxylated fluorene type di(meth)acrylate, propoxylated fluorene type di(meth)acrylate, ethoxylated propoxylated fluorene type di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated propoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated propoxylated pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexa(meth)acrylate and other aliphatic (meth)acrylates; aromatic epoxy (meth)acrylates such as bisphenol type epoxy (meth)acrylate, novolac type epoxy (meth)acrylate, cresol novolac type epoxy (meth)acrylate, etc.

[0047] In terms of achieving both a reduction effect on the connection resistance and suppressing the flow of particles, based on the total mass of the component (B1), the content of the polyfunctional (2 or more functional) (meth)acrylate may be, for example, 40 to 100% by mass, 50 to 100% by mass, or 60 to 100% by mass.

[0048] In addition to the polyfunctional (2 or more functional) (meth)acrylate, the component (B1) may also contain a monofunctional (meth)acrylate. Examples of the monofunctional (meth)acrylate include (meth)acrylic acid; (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid isobutyl ester, (meth)acrylic acid tert-butyl ester, (meth)acrylic acid butoxyethyl ester, (meth)acrylic acid isopentyl ester, (meth)acrylic acid hexyl ester, 2-ethylhexyl (meth)acrylate, (meth)acrylic acid heptyl ester, octylheptyl (meth)acrylate, (meth)acrylic acid nonyl ester, (meth)acrylic acid decyl ester, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethoxypolypropylene glycol (meth)acrylate, mono(2-(meth)acryloyloxyethyl) succinate and other aliphatic (meth)acrylates; benzyl (meth)acrylate, phenyl (meth)acrylate, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, p-isopropylphenylphenoxyethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, 1-naphthyloxyethyl (meth)acrylate, 2-naphthyloxyethyl (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-naphthyloxy)propyl (meth)acrylate, 2-hydroxy-3-(2-naphthyloxy)propyl (meth)acrylate and other aromatic (meth)acrylates; (meth)acrylic acid glycidyl ester and other (meth)acrylates having an epoxy group, 3,4-epoxycyclohexylmethyl (meth)acrylate and other (meth)acrylates having an alicyclic epoxy group, (3-ethyloxetane-3-yl)methyl (meth)acrylate and other (meth)acrylates having an oxetanyl group, etc.

[0049] Based on the total mass of the component (B1), 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.

[0050] (B) component curable products can, for example, have polymerizable groups that react through mechanisms other than free radicals. Polymerizable groups that react through mechanisms other than free radicals can, for example, be cationic polymerizable groups that react through cations. Examples of cationic polymerizable groups include epoxy groups such as glycidyl groups, alicyclic epoxy groups such as epoxycyclohexylmethyl groups, and oxetanyl groups such as ethyloxetanylmethyl groups. Curable products of component (B) having polymerizable groups that react through mechanisms other than free radicals can be introduced, for example, by using (meth)acrylates having epoxy groups, (meth)acrylates having alicyclic epoxy groups, (meth)acrylates having oxetanyl groups, etc., which are (meth)acrylates having polymerizable groups that react through mechanisms other than free radicals, as component (B). From the perspective of improving reliability, the mass ratio of the (meth)acrylate having a polymerizable group that reacts through a mechanism other than free radicals to the total mass of component (B1) (mass of the (meth)acrylate having a polymerizable group that reacts through a mechanism other than free radicals (loading amount) / total mass of component (B1) (loading amount)) can be, for example, 0 to 0.7, 0 to 0.5, or 0 to 0.3.

[0051] In addition to polyfunctional (two or more functional groups) and monofunctional (meth)acrylates, component (B1) can also contain other free radical polymerizable compounds. Examples of other free radical polymerizable compounds include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, and imide (Nadiimide) derivatives. Based on the total mass of component (B1), the content of other free radical polymerizable compounds can be, for example, 0 to 40% by mass.

[0052] Component (B2): Photo radical polymerization initiator

[0053] Component (B2) is a photoinitiator that generates free radicals upon irradiation with light having a wavelength in the range of 150 to 750 nm, preferably in the range of 254 to 405 nm, and more preferably having a wavelength of 365 nm (e.g., ultraviolet light). For component (B2), one type can be used alone, or multiple types can be used in combination.

[0054] (B2) component decomposes by light and generates free radicals. That is, the (B2) component is a compound that generates free radicals by applying light energy from the outside. The (B2) component can be a compound having a structure such as an oxime ester structure, a bisimidazole structure, an acridine structure, an α - aminoalkyl phenyl ketone structure, an aminodiphenyl ketone structure, an N - phenylglycine structure, an acylphosphine oxide structure, a benzyl dimethyl ketal structure, an α - hydroxyalkyl phenyl ketone structure, etc. Regarding the (B2) component, one kind can be used alone, or multiple kinds can be used in combination. From the viewpoints of easily obtaining the desired melt viscosity and more excellent reduction effect of the contact resistance, the (B2) component can be a compound having at least one structure selected from the group consisting of an oxime ester structure, an α - aminoalkyl phenyl ketone structure, and an acylphosphine oxide structure.

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

[0056] Specific examples of the compound having an α - aminoalkyl phenyl ketone structure include 2 - methyl - 1 - [4 - (methylthio) phenyl] - 2 - morpholinopropan - 1 - one, 2 - benzyl - 2 - dimethylamino - 1 - (morpholinophenyl) - butan - 1 - one, etc.

[0057] Specific examples of the compound having an acylphosphine oxide structure include bis(2,6 - dimethoxybenzoyl) - 2,4,4 - trimethyl - pentyl phosphine oxide, bis(2,4,6 - trimethylbenzoyl) - phenyl phosphine oxide, 2,4,6 - trimethylbenzoyl - diphenyl phosphine oxide, etc.

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

[0059] In terms of suppressing the flow of conductive particles, based on the total mass of the first adhesive layer, the content of the cured product of component (B) can be 1% by mass or more, 5% by mass or more, or 10% by mass or more. In terms of exhibiting low resistance in low-pressure encapsulation, based on the total mass of the first adhesive layer, the content of the cured product of component (B) can be 50% by mass or less, 40% by mass or less, or 30% by mass or less. If the content of the cured product of component (B) is within the above range, the effects of the present invention tend to be significantly exerted. In addition, the content of component (B) in the composition or the composition layer (based on the total mass of the composition or the composition layer) can be the same as the above range.

[0060] (C) component: thermosetting resin component

[0061] Regarding component (C), as long as it is a resin component that is cured by light irradiation, there is no particular limitation. However, when component (B) is a resin component having radical curability, in terms of more excellent connection resistance, component (C) can be a resin component having cationic curability. Component (C) can include, for example, a cationically polymerizable compound (hereinafter, sometimes referred to as "(C1) component") and a thermal cationic polymerization initiator (hereinafter, sometimes referred to as "(C2) component"). Component (C) can be a component composed of (C1) component and (C2) component. In addition, the first thermosetting resin component, the second thermosetting resin component, and the third thermosetting resin component respectively refer to the thermosetting resin components contained in the first adhesive layer, the second adhesive layer, and the third adhesive layer. The components (for example, (C1) component, (C2) component, etc.) and contents included in the first thermosetting resin component, the second thermosetting resin component, and the third thermosetting resin component can be the same as or different from each other.

[0062] (C1) component: cationically polymerizable compound

[0063] (C1) component is a compound that crosslinks by reacting with (C2) component by heat. In addition, (C1) component refers to a compound that does not have a radical polymerizable group that reacts by radicals, and (C1) component is not included in (B1) component. In terms of further improving the effect of reducing connection resistance and more excellent connection reliability, (C1) component can be, for example, at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds. Regarding (C1) component, one kind can be used alone, or multiple kinds can be used in combination. In terms of easily obtaining the desired melt viscosity, (C1) component preferably contains both at least one oxetane compound and at least one alicyclic epoxy compound.

[0064] As the oxetane compound of the (C1) component, any compound having an oxetanyl group and not having a free-radical polymerizable group can be used without particular limitation. As commercially available products of the oxetane compound, for example, ETERNACOLL OXBP (trade name, 4,4'-bis[(3-ethyl-3-oxetanylmethoxy)methyl]biphenyl, manufactured by UBE INDUSTRIES,LTD.), OXSQ, OXT-121, OXT-221, OXT-101, OXT-212 (trade name, manufactured by TOAGOSEI CO.,LTD.) etc. can be cited. These can be used alone as one kind of compound, or multiple kinds can be used in combination.

[0065] As the alicyclic epoxy compound of the (C1) component, any compound having an alicyclic epoxy group (for example, epoxycyclohexyl group) and not having a free-radical polymerizable group can be used without particular limitation. As commercially available products of the alicyclic epoxy compound, for example, EHPE3150, EHPE3150CE, CELLOXIDE8010, CELLOXIDE2021P, CELLOXIDE2081 (trade name, manufactured by Corporation Daicel Corporation) etc. can be cited. These can be used alone as one kind of compound, or multiple kinds can be used in combination.

[0066] (C2) component: Thermal cationic polymerization initiator

[0067] (C2) component is a thermal polymerization initiator that initiates polymerization by generating an acid or the like upon heating. (C2) component can be a salt compound composed of a cation and an anion. Regarding the (C2) component, for example, sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, anilinium salts etc. having anions such as BF4 - , BR4 - (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups.), PF6 - , SbF6 - , AsF6 - etc. can be cited. These can be used alone as one kind, or multiple kinds can be used in combination.

[0068] From the viewpoint of storage stability, (C2) component can be, for example, a salt compound having an anion containing boron as a constituent element, that is, BF4 - or BR4 - (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups.). The anion containing boron as a constituent element can be BR4 - , and more specifically, can be tetra(pentafluorophenyl)borate.

[0069] In terms of the view of having resistance to substances that may cause curing inhibition relative to cationic curing, the onium salt as the (C2) component can be, for example, an aniline salt. As aniline salt compounds, for example, N,N-dialkylaniline salts such as N,N-dimethylaniline salt and N,N-diethylaniline salt can be cited.

[0070] (C2) component can be an aniline salt having an anion containing boron as a constituent element. As commercially available products of such salt compounds, for example, CXC-1821 (trade name, manufactured by King Industries, Inc.) can be cited.

[0071] In terms of ensuring the formability and curability of the adhesive film for forming the first adhesive layer, the content of the (C2) component can be, for example, 0.1 to 20 parts by mass, 1 to 18 parts by mass, 3 to 15 parts by mass, or 5 to 12 parts by mass with respect to 100 parts by mass of the (C1) component.

[0072] In terms of ensuring the curability of the adhesive film for forming the first adhesive layer, based on the total mass of the first adhesive layer, the content of the (C) component can be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more. In terms of ensuring the formability of the adhesive film for forming the first adhesive layer, based on the total mass of the first adhesive layer, the content of the (C) component can be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less. If the content of the (C) component is within the above range, the effects of the present invention tend to be significantly exhibited. In addition, the content of the (C) component in the composition or the composition layer (based on the total mass of the composition or the composition layer) can be the same as the above range.

[0073] [Other components]

[0074] In addition to the cured products of the (A) component, the (B) component, and the (C) component, the first adhesive layer 1 can further contain other components. As other components, for example, thermoplastic resins (hereinafter sometimes referred to as the “(D) component”), coupling agents (hereinafter sometimes referred to as the “(E) component”), filler materials (hereinafter sometimes referred to as the “(F) component”), etc. can be cited.

[0075] As the component (D), for example, a phenoxy resin, a polyester resin, a polyamide resin, a polyurethane resin, a polyesteramide urethane resin, an acrylic rubber, an epoxy resin (solid at 25°C), etc. may be cited. These may be used alone or in combination of two or more. By the composition containing the components (A), (B) and (C) further containing the component (D), a composition layer (and further the first adhesive layer 1) can be easily formed from the composition. Among these, the component (D) may be, for example, a phenoxy resin. Based on the total mass of the first adhesive layer, 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 may also be 70% by mass or less, 50% by mass or less, or 30% by mass or less. In addition, 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.

[0076] As the component (E), for example, a silane coupling agent having an organic functional group such as (meth)acryloyl group, mercapto group, amino group, imidazolyl group, epoxy group, etc., a silane compound such as tetraalkoxysilane, a tetraalkoxy titanate derivative, a polydialkyl titanate derivative, etc. may be cited. These may be used alone or in combination of two or more. By the first adhesive layer 1 containing the component (E), the adhesiveness can be further improved. The component (E) may be, for example, a silane coupling agent. Based on the total mass of the first adhesive layer, the content of the component (E) may be 0.1 to 10% by mass. In addition, 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.

[0077] As the component (F), for example, a non-conductive filler (for example, non-conductive particles) may be cited. The component (F) may be either an inorganic filler or an organic filler. As the inorganic filler, for example, metal oxide fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titanium oxide fine particles, zirconium oxide fine particles, etc.; inorganic fine particles such as metal nitride fine particles may be cited. As the organic filler, for example, organic fine particles such as silicone fine particles, methacrylate / butadiene / styrene fine particles, acrylic / silicone fine particles, polyamide fine particles, polyimide fine particles, etc. may be cited. These may be used alone or in combination of two or more. The component (F) may be, for example, silica fine particles. Based on the total mass of the first adhesive layer, the content of the component (F) may be 0.1 to 10% by mass. In addition, 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.

[0078] [Other additives]

[0079] The first adhesive layer 1 may further contain other additives such as a softening agent, a promoter, an anti-degradant, a colorant, a flame retardant, a thixotropic agent, etc. Based on the total mass of the first adhesive layer, the content of other additives may be, for example, 0.1 to 10% by mass. In addition, 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.

[0080] The thickness d1 of the first adhesive layer 1 is 5 μm or less, and may be, for example, 4.5 μm or less, 4.0 μm or less, 3.5 μm or less, 3.0 μm or less, or 2.5 μm or less. The thickness d1 of the first adhesive layer 1 being 5 μm or less can further suppress the fluidity of conductive particles during circuit connection. Therefore, even in the case of encapsulation under low pressure, the capture rate of conductive particles between the opposing electrodes of the circuit connection structure can be increased, and the connection resistance can be reduced. The thickness d1 of the first adhesive layer 1 may be, for example, 0.1 μm or more or 0.7 μm or more. In addition, the thickness d1 of the first adhesive layer 1 can be obtained, for example, by the method described in the examples. And, as Figure 1 shown, when a part of the conductive particles 4 protrudes from the surface of the first adhesive layer 1 (for example, protrudes toward the second adhesive layer 2 side), the distance from the surface 2a on the side of the first adhesive layer 1 opposite to the second adhesive layer 2 side to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 at the separated part of the adjacent conductive particles 4, 4 (the distance represented by d1 in Figure 1 is the thickness of the first adhesive layer 1, and the exposed part of the conductive particles 4 is not included in the thickness of the first adhesive layer 1. The length of the exposed part of the conductive particles 4 may be, for example, 0.1 μm or more and may also be 5 μm or less.

[0081] <Second Adhesive Layer>

[0082] The second adhesive layer 2 contains the component (C). The component (C1) and the component (C2) used in the component (C) in the second adhesive layer 2 (i.e., the second thermosetting resin component) are the same as the component (C1) and the component (C2) used in the component (C) in the first adhesive layer 1 (i.e., the first thermosetting resin component), so detailed description is omitted here. The second thermosetting resin component may be the same as or different from the first thermosetting resin component.

[0083] In terms of maintaining reliability, based on the total mass of the second adhesive layer, the content of component (C) can be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more. In terms of preventing resin bleeding defects on the reel as a supply method, based on the total mass of the second adhesive layer, the content of component (C) can be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less.

[0084] The second adhesive layer 2 may further contain other components and other additives in the first adhesive layer 1. The preferred forms of other components and other additives are the same as those of the first adhesive layer 1.

[0085] Based on the total mass of the second adhesive layer, the content of component (D) can be 1% by mass or more, 5% by mass or more, or 10% by mass or more, and can also be 80% by mass or less, 60% by mass or less, or 40% by mass or less.

[0086] Based on the total mass of the second adhesive layer, the content of component (E) can be 0.1 to 10% by mass.

[0087] Based on the total mass of the second adhesive layer, the content of component (F) can be 1% by mass or more, 10% by mass or more, or 30% by mass or more, and can also be 90% by mass or less, 70% by mass or less, or 50% by mass or less.

[0088] Based on the total mass of the second adhesive layer, the content of other additives can be, for example, 0.1 to 10% by mass.

[0089] The thickness d2 of the second adhesive layer 2 can be appropriately set according to the height of the electrodes of the circuit components to be bonded, etc. In terms of being able to sufficiently fill the space between the electrodes to seal the electrodes and obtaining better connection reliability, the thickness d2 of the second adhesive layer 2 can be 5 μm or more or 7 μm or more, and can also be 15 μm or less or 11 μm or less. In addition, the thickness d2 of the second adhesive layer 2 can be obtained, for example, by the method described in the examples. And, when a part of the conductive particles 4 protrudes from the surface of the first adhesive layer 1 (for example, protrudes toward the second adhesive layer 2 side), the distance from the surface 3a on the side of the second adhesive layer 2 opposite to the first adhesive layer 1 side to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 at the separated part of the adjacent conductive particles 4, 4 (the distance represented by d2 in Figure 1 is the thickness of the second adhesive layer 2.

[0090] The thickness of the adhesive film 10 (the total thickness of all the layers constituting the adhesive film 10, in Figure 1In this case, the total of the thickness d1 of the first adhesive layer 1 and the thickness d2 of the second adhesive layer 2 (for example) can be 5 μm or more, or 8 μm or more, and can also be 30 μm or less, or 20 μm or less.

[0091] In the adhesive film 10, the conductive particles 4 are dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 is an anisotropic conductive adhesive film having anisotropic conductivity. The adhesive film 10 is interposed between a first circuit component having a first electrode and a second circuit component having a second electrode, and is used for thermocompression bonding the first circuit component and the second circuit component to electrically connect the first electrode and the second electrode to each other.

[0092] According to the adhesive film 10, it is possible to suppress the fluidity of the conductive particles during circuit connection while suppressing the decrease in resin excludability by curing the photocurable resin component. Moreover, since the thickness of the first adhesive layer is 5 μm or less, it is possible to further suppress the fluidity of the conductive particles during circuit connection. Therefore, even in the case of encapsulation under low pressure, it is possible to increase the capture rate of the conductive particles between the opposing electrodes of the circuit connection structure and reduce the connection resistance. Such an adhesive film 10 can be applied to COP encapsulation.

[0093] As described above, the adhesive film of the present embodiment has been described, but the present invention is not limited to the above embodiment.

[0094] The adhesive film can be composed of, for example, two layers, namely, the first adhesive layer and the second adhesive layer, or can be composed of three or more layers including the two layers of the first adhesive layer and the second adhesive layer. The adhesive film can also include, for example, a third adhesive layer provided on the side of the first adhesive layer opposite to the second adhesive layer and containing a (third) thermosetting resin component. In the adhesive film, there can be a first region formed by the first adhesive film (first adhesive layer), that is, the first region, and a third region formed by the third adhesive film (third adhesive layer) and adjacent to the first region. The adhesive film can further include a third region provided adjacent to the side of the first region opposite to the second region and containing a (third) thermosetting resin component.

[0095] The third adhesive layer contains component (C). The component (C1) and component (C2) used in the component (C) in the third adhesive layer (that is, the third thermosetting resin component) are the same as the component (C1) and component (C2) used in the component (C) in the first adhesive layer 1 (that is, the first thermosetting resin component), and thus detailed description thereof is omitted here. The third thermosetting resin component can be the same as or different from the first thermosetting resin component. The third thermosetting resin component can be the same as or different from the second thermosetting resin component.

[0096] From the viewpoint of imparting good transferability and peel resistance, based on the total mass of the third adhesive layer, the content of component (C) can be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more. From the viewpoint of imparting good half-cutability and adhesion resistance (inhibiting resin bleeding from the reel), based on the total mass of the third adhesive layer, the content of component (C) can be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less.

[0097] The third adhesive layer may further contain other components and other additives in the first adhesive layer 1. The preferred modes of other components and other additives are the same as those of the first adhesive layer 1.

[0098] Based on the total mass of the third adhesive layer, the content of component (D) can be 10% by mass or more, 20% by mass or more, or 30% by mass or more, and can also be 80% by mass or less, 70% by mass or less, or 60% by mass or less.

[0099] Based on the total mass of the third adhesive layer, the content of component (E) can be 0.1 to 10% by mass.

[0100] Based on the total mass of the third adhesive layer, the content of component (F) can be 1% by mass or more, 3% by mass or more, or 5% by mass or more, and can also be 50% by mass or less, 40% by mass or less, or 30% by mass or less.

[0101] Based on the total mass of the third adhesive layer, the content of other additives can be, for example, 0.1 to 10% by mass.

[0102] The thickness of the third adhesive layer can be appropriately set according to the height of the electrodes of the circuit components to be bonded, etc. From the viewpoint of being able to sufficiently fill the space between the electrodes to seal the electrodes and obtaining better connection reliability, the thickness of the third adhesive layer can be 0.2 μm or more and can also be 3.0 μm or less. In addition, the thickness of the third adhesive layer can be obtained, for example, by the method described in the examples.

[0103] Moreover, the adhesive film for circuit connection in the above-described embodiment is an anisotropic conductive adhesive film having anisotropic conductivity, but the adhesive film for circuit connection can be a conductive adhesive film not having anisotropic conductivity.

[0104] <Manufacturing method of adhesive film for circuit connection>

[0105] The manufacturing method of the adhesive film for circuit connection of one embodiment may include, for example: a step (the first step) of irradiating light on a composition layer made of a composition containing component (A), component (B), and component (C) (the first thermosetting resin component) to form a first adhesive layer; and a step (the second step) of laminating a second adhesive layer containing component (C) (the second thermosetting resin component) on the first adhesive layer. The first step may be a step of forming a first adhesive layer with a thickness of 5 μm or less. This manufacturing method may further include the following step (the third step): laminating a third adhesive layer containing component (C) (the third thermosetting resin component) on the layer on the side of the first adhesive layer opposite to the second adhesive layer.

[0106] In the first step, for example, first, a composition containing component (A), component (B), component (C), and other components and other additives added as needed is stirred, mixed, kneaded, etc. in an organic solvent, so that it is dissolved or dispersed to prepare a varnish composition. Thereafter, using an air knife coater, a roll coater, an applicator, a bevel wheel coater, a die coater, etc., the varnish composition is coated on a substrate that has been subjected to a release treatment, and then the organic solvent is volatilized by heating to form a composition layer made of the composition on the substrate. At this time, by adjusting the coating amount of the varnish composition, the thickness of the finally obtained first adhesive layer (the first adhesive film) can be adjusted. Then, light is irradiated on the composition layer made of the composition to cure component (B) in the composition layer, and a first adhesive layer is formed on the substrate. The first adhesive layer can be referred to as the first adhesive film.

[0107] Regarding the organic solvent used in the preparation of the varnish composition, there is no particular limitation as long as it has the property of being able to uniformly dissolve or disperse each component. As such an organic solvent, for example, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, etc. can be cited. These organic solvents can be used alone or in combination of two or more. The stirring, mixing, or kneading during the preparation of the varnish composition can be carried out, for example, using a stirrer, a grinder, a three-roll mill, a ball mill, a bead mill, a homogenizing disperser, etc.

[0108] Regarding the substrate, there is no particular limitation as long as it has heat resistance capable of withstanding the heating conditions during the volatilization of the organic solvent. As such a substrate, for example, a substrate (such as a film) made of stretched polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene / vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber-based, liquid crystal polymer, etc. can be used.

[0109] The heating conditions when volatilizing the organic solvent from the varnish composition coated on the substrate can be appropriately set according to the organic solvent used, etc. The heating conditions can be, for example, 40 to 120 °C and 0.1 to 10 minutes.

[0110] In the light irradiation in the curing step, it is preferable to use irradiation light (for example, ultraviolet light) including wavelengths in the range of 150 to 750 nm. Regarding the light irradiation, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, etc. can be used. The cumulative light amount of the light irradiation can be appropriately set, but for example, it can be 500 to 3000 mJ / cm 2 .

[0111] The second step is a step of laminating a second adhesive layer on the first adhesive layer. In the second step, for example, first, the component (C), and other components and other additives added as needed are used and no light irradiation is performed. Other than this, in the same manner as in the first step, a second adhesive layer is formed on the substrate to obtain a second adhesive film. Then, by laminating the first adhesive film and the second adhesive film, the second adhesive layer can be laminated on the first adhesive layer. And, 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 coated on the first adhesive layer to volatilize the organic solvent, so the second adhesive layer can also be laminated on the first adhesive layer.

[0112] As a method of laminating the first adhesive film and the second adhesive film, for example, methods such as hot pressing, roll lamination, and vacuum lamination can be cited. Regarding the lamination, for example, it can be performed under temperature conditions of 0 to 80 °C.

[0113] The third step is a step of laminating a third adhesive layer on the layer of the first adhesive layer on the side 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. Then, the third adhesive film is laminated on the side of the first adhesive film opposite to the second adhesive film, so the third adhesive layer can be laminated on the layer of the first adhesive layer on the side opposite to the second adhesive layer. And, in the third step, for example, in the same manner as in the second step, a varnish composition is coated on the layer of the first adhesive layer on the side opposite to the second adhesive layer to volatilize the organic solvent, so the second adhesive layer can also be laminated on the first adhesive layer. The method and conditions of lamination are the same as those in the second step.

[0114] <Circuit connection structure and its manufacturing method>

[0115] Hereinafter, a circuit connection structure using the above-described adhesive film 10 for circuit connection as a circuit connection material and a method for manufacturing the same will be described.

[0116] Figure 2 FIG. is a schematic cross-sectional view showing an embodiment of the circuit connection structure. As Figure 2 shown, the circuit connection structure 20 includes: a first circuit component 13 having a first electrode 12 formed on a first circuit board 11 and a main surface 11a of the first circuit board 11; a second circuit component 16 having a second electrode 15 formed on a second circuit board 14 and a main surface 14a of the second circuit board 14; and a circuit connection portion 17 disposed between the first circuit component 13 and the second circuit component 16 to electrically connect the first electrode 12 and the second electrode 15 to each other.

[0117] The first circuit component 13 and the second circuit component 16 may be the same as or different from each other. The first circuit component 13 and the second circuit component 16 may be a glass substrate or a plastic substrate formed with electrodes, a printed circuit board, a ceramic circuit board, a flexible circuit board, an IC chip, etc. The first circuit board 11 and the second circuit board 14 may be formed of inorganic substances such as semiconductors, glass, and ceramics, organic substances such as polyimide and polycarbonate, composites such as glass / epoxy, etc. Among these, since the above-described adhesive film 10 for circuit connection can be applied to COP packaging, the first circuit component 13 may be, for example, a plastic substrate made of an organic substance such as polyimide, polycarbonate, polyethylene terephthalate, or cycloolefin polymer, and the second circuit board 14 may be, for example, an IC chip.

[0118] The first electrode 12 and the second electrode 15 may be electrodes containing metals such as gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, and titanium, oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc. The first electrode 12 and the second electrode 15 may be electrodes formed by laminating two or more of these metals, oxides, etc. The electrode formed by laminating two or more may be two or more layers, or may be three or more layers. In the case where the first circuit component 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 Figure 2 it, the first electrode 12 is a circuit electrode and the second electrode 15 is a bump electrode.

[0119] The circuit connection portion 17 includes the cured product of the adhesive film 10 described above. The circuit connection portion 17 can be made of the cured product of the adhesive film 10 described above. For example, the circuit connection portion 17 has: a first cured product region 18, which is located on the side of the first circuit component 13 in the direction in which the first circuit component 13 and the second circuit component 16 face each other (hereinafter referred to as the "opposing direction"), and is made of the cured product of the component (B) other than the conductive particles 4 and the cured product of the component (C) etc. in the first adhesive layer; a second cured product region 19, which is located on the side of the second circuit component 16 in the opposing direction, and is made of the cured product of the component (C) etc. in the second adhesive layer; and the conductive particles 4, which are at least interposed between the first electrode 12 and the second electrode 15 to electrically connect the first electrode 12 and the second electrode 15 to each other. As Figure 2 shown, the circuit connection portion 17 does not have to have two distinct regions between the first cured product region 18 and the second cured product region 19, and a single cured product region can be formed by mixing the cured product derived from the first adhesive layer and the cured product derived from the second adhesive layer.

[0120] Figure 3 It is a schematic cross-sectional view showing an embodiment of a method for manufacturing a circuit connection structure. Figure 3 (a) and Figure 3 (b) are schematic cross-sectional views showing each step. As Figure 3 shown, the method for manufacturing the circuit connection structure 20 includes the following steps: interposing the adhesive film 10 between the first circuit component 13 having the first electrode 12 and the second circuit component 16 having the second electrode 15, and thermocompression bonding the first circuit component 13 and the second circuit component 16 to electrically connect the first electrode 12 and the second electrode 15 to each other.

[0121] Specifically, as Figure 3 (a) shows, first, a first circuit component 13 having a first electrode 12 formed on a first circuit board 11 and a main surface 11a of the first circuit board 11, and a second circuit component 16 having a second electrode 15 formed on a second circuit board 14 and a main surface 14a of the second circuit board 14 are prepared.

[0122] Next, the first circuit component 13 and the second circuit component 16 are arranged such that the first electrode 12 and the second electrode 15 face each other, and the adhesive film 10 is arranged between the first circuit component 13 and the second circuit component 16. For example, as Figure 3As shown in (a), the first adhesive layer 1 side is opposed to the main surface 11a of the first circuit board 11, and the adhesive film 10 is laminated on the first circuit component 13. Then, the first electrode 12 on the first circuit board 11 and the second electrode 15 on the second circuit board 14 are opposed to each other, and the second circuit component 16 is disposed on the first circuit component 13 on which the adhesive film 10 is laminated.

[0123] And, as Figure 3 shown in (b), while heating the first circuit component 13, the adhesive film 10, and the second circuit component 16, pressure is applied to the first circuit component 13 and the second circuit component 16 in the thickness direction, whereby the first circuit component 13 and the second circuit component 16 are thermocompression bonded to each other. At this time, in Figure 3 (b) as shown by the arrow, the second adhesive layer 2 has an uncured thermosetting component that can flow, and thus flows in a manner of filling the gaps between the second electrodes 15 and is cured by the above heating. Therefore, the first electrode 12 and the second electrode 15 are electrically connected to each other via the conductive particles 4, and the first circuit component 13 and the second circuit component 16 are bonded to each other, thereby obtaining Figure 2 the circuit connection structure 20 shown in. In the manufacturing method of the circuit connection structure 20 of the present embodiment, it can be said that a layer formed by curing a part of the first adhesive layer 1 by light irradiation, so the conductive particles 4 are fixed in the first adhesive layer 1, and the first adhesive layer 1 hardly flows during the above thermocompression bonding, and the conductive particles are efficiently captured between the opposed electrodes, so the connection resistance between the opposed first electrode 12 and the second electrode 15 can be reduced. And, the thickness of the first adhesive layer is 5 μm or less, whereby the fluidity of the conductive particles during circuit connection can be further suppressed.

[0124] The heating temperature during thermocompression bonding can be appropriately set, but for example, it can be 50 to 190 °C. Regarding the pressure, as long as it is within the range that does not damage the adherend, there is no particular limitation, but in the case of COP packaging, for example, the area conversion pressure on the bump electrode can be 0.1 to 50 MPa. And, in the case of COG packaging, for example, the area conversion pressure on the bump electrode can be 10 to 100 MPa. These heating and pressurization times can be in the range of 0.5 to 120 seconds.

[0125] Examples

[0126] Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples.

[0127] [Production of the first adhesive layer, the second adhesive layer, and the third adhesive layer]

[0128] In the production of the first adhesive layer, the second adhesive layer, and the third adhesive layer, the materials shown below were used.

[0129] Component (A): Conductive particles

[0130] Conductive particle A-1: Conductive particles with an average particle size of 3.2 μm are used. In these conductive particles, the surface of the plastic core is Ni-plated, and the outermost surface is Pd-displacement plated.

[0131] Component (B): Photo-curable resin component

[0132] By combining (B1) a radically polymerizable compound and (B2) a photo-radical polymerization initiator, it can function as a photo-curable resin component (i.e., component (B)). On the other hand, by combining (B1) a radically polymerizable compound and (b2) a thermal radical polymerization initiator, it can function as a thermosetting component.

[0133] Component (B1): Radically polymerizable compound

[0134] Radically polymerizable compound B1-1: NK Ester A-BPEF (ethoxylated fluorene-type bis(meth)acrylate (2-functional), manufactured by SHIN-NAKAMURA CHEMICAL CO,LTD.), a substance diluted with an organic solvent to a non-volatile component of 70% by mass is used.

[0135] Radically polymerizable compound B1-2: RIPOXY VR-90 (bisphenol A-type epoxy (meth)acrylate (2-functional) (vinyl ester resin), manufactured by SHOWA DENKO K.K.), used with a non-volatile component of 100% by mass.

[0136] Radically polymerizable compound B1-3: CYCLOMER M100 (methacrylate with an alicyclic epoxy group (mono-functional), manufactured by Daicel Corporation), used with a non-volatile component of 100% by mass.

[0137] Component (B2): Photo-radical polymerization initiator

[0138] Photo-radical polymerization initiator B2-1: Irgacure OXE-02 (a compound with an oxime ester structure, manufactured by BASF), a substance diluted with an organic solvent to a non-volatile component of 10% by mass is used.

[0139] Component (b2): Thermal radical polymerization initiator

[0140] Thermal free radical polymerization initiator b2-1: PERCUMYL D (dialkyl peroxide, manufactured by NOF CORPORATION), a substance diluted with an organic solvent to a non-volatile component of 20% by mass

[0141] (C) component: Thermosetting resin component

[0142] By combining (C1) cationically polymerizable compound and (C2) thermal cationic polymerization initiator, it can function as a thermosetting component (i.e., (C) component). On the other hand, by combining (C1) cationically polymerizable compound and (c2) photo cationic polymerization initiator, it can function as a photocurable component.

[0143] (C1) component: Cationically polymerizable compound

[0144] Cationically polymerizable compound C1-1: ETERNACOLL OXBP (oxetane compound, manufactured by UBE INDUSTRIES, LTD.), used with a non-volatile component of 100% by mass

[0145] Cationically polymerizable compound C1-2: OXSQ (oxetane compound, manufactured by TOAGOSEI CO., LTD.), used with a non-volatile component of 100% by mass

[0146] Cationically polymerizable compound C1-3: EHPE3150 (alicyclic epoxy compound, manufactured by Daicel Corporation), a substance diluted with an organic solvent to a non-volatile component of 70% by mass

[0147] Cationically polymerizable compound C1-4: CELLOXIDE8010 (alicyclic epoxy compound, manufactured by Daicel Corporation), used with a non-volatile component of 100% by mass

[0148] Cationically polymerizable compound C1-5: CELLOXIDE2021P (alicyclic epoxy compound, manufactured by Daicel Corporation), used with a non-volatile component of 100% by mass

[0149] Cationically polymerizable compound C1-6: A mixture obtained by kneading butadiene rubber particles with a primary particle size of less than 1 μm in a ratio of 3:1 (cationically polymerizable compound: butadiene rubber particles) in cationically polymerizable compound C1-5, used with a non-volatile component of 100% by mass

[0150] (C2) component: Thermal cationic polymerization initiator

[0151] Thermal cationic polymerization initiator C2-1: CXC-1821 (N-(p-methoxybenzyl)-N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, manufactured by King Industries, Inc.), used with 100% by mass of non-volatile content

[0152] (c2) Component: Photo cationic polymerization initiator

[0153] Photo cationic polymerization initiator c2-1: CPI-310B (manufactured by San-Apro Ltd.), a substance diluted with an organic solvent to a non-volatile content of 10% by mass is used

[0154] (D) Component: Thermoplastic resin

[0155] Thermoplastic resin D-1: phenotote FX-293 (phenoxy resin, manufactured by NIPPON STEEL Chemical&Material Co., Ltd.), a substance diluted with an organic solvent to a non-volatile content of 40% by mass is used

[0156] Thermoplastic resin D-2: phenotote YP-50S (phenoxy resin, manufactured by NIPPON STEEL Chemical&Material Co., Ltd.), a substance diluted with an organic solvent to a non-volatile content of 40% by mass is used

[0157] Thermoplastic resin D-3: TOPR-300 (phenoxy resin, manufactured by NIPPON STEEL Chemical&Material Co., Ltd.), a substance diluted with an organic solvent to a non-volatile content of 60% by mass is used

[0158] Thermoplastic resin D-4: jER1007 (epoxy resin, manufactured by Mitsubishi Chemical Corporation), a substance diluted with an organic solvent to a non-volatile content of 70% by mass is used

[0159] Thermoplastic resin D-5: phenotote ZX-1356-2 (phenoxy resin, manufactured by NIPPON STEEL Chemical&Material Co., Ltd.), a substance diluted with an organic solvent to a non-volatile content of 40% by mass is used

[0160] (E) Component: Coupling agent

[0161] Coupling agent E-1: SH-6040 (3-glycidoxypropyltrimethoxysilane, manufactured by Dow Corning Toray Co., Ltd.), used with 100% by mass of non-volatile content

[0162] (F) Component: Filler

[0163] Filler F-1: ADMANANO YA050-MJL (silica microparticles, manufactured by Admatechs Company Limited), using a substance diluted with an organic solvent to a non-volatile component of 50% by mass

[0164] Filler F-2: AEROSIL R805 (silica microparticles, manufactured by Evonik Industries AG), using a substance diluted with an organic solvent to a non-volatile component of 10% by mass

[0165] Filler F-3: ADMAFINE SE2050 (silica microparticles, manufactured by Admatechs Company Limited), using a substance diluted with an organic solvent to a non-volatile component of 70% by mass

[0166] <Fabrication of the First Adhesive Film (First Adhesive Layer)>

[0167] After obtaining a composition by mixing the materials shown in Table 1 at the composition ratios shown in Table 1 (the values in Table 1 refer to the amount of non-volatile components), while applying a magnetic field on a PET (polyethylene terephthalate) film that has been subjected to a release treatment, coating is performed, and the organic solvent, etc. is hot air dried at 70 °C for 5 minutes, thereby obtaining composition layers 1a to 1i made of a composition containing each component. Coating was performed on composition layers 1a to 1i so that the final dried thickness became the thicknesses described in Tables 4 and 5. Next, regarding composition layers 1a to 1f, light irradiation (UV irradiation: metal halide lamp, cumulative light amount: 1900 - 2300 mJ / cm 2 ) was performed on each layer, thereby obtaining the first adhesive films 1A to 1F. Regarding composition layer 1g, light irradiation (UV irradiation: metal halide lamp, cumulative light amount: 1000 - 1500 mJ / cm 2 ) was performed on this layer, thereby obtaining the first adhesive film 1G. On the other hand, composition layers 1h and 1i were not processed and directly used as the first adhesive films 1H and 1I.

[0168] [Table 1]

[0169]

[0170] <Fabrication of the Second Adhesive Film (Second Adhesive Layer)>

[0171] After mixing the materials shown in Table 2 at the composition ratios shown in Table 2 (the values in Table 2 refer to the amount of non-volatile components), it was coated on a demolded PET (polyethylene terephthalate) film, and organic solvents and the like were dried, whereby the second adhesive films 2A to 2C containing each component were obtained. The second adhesive film 2A was coated so that the thickness after drying became 9 μm, the second adhesive film 2B was coated so that the thickness after drying became 10 μm, and the second adhesive film 2C was coated so that the thickness after drying became 7 μm.

[0172] [Table 2]

[0173]

[0174] <Third Adhesive Film (Third Adhesive Layer)>

[0175] After mixing the materials shown in Table 3 at the composition ratios shown in Table 3 (the values in Table 3 refer to the amount of non-volatile components), it was coated on a demolded PET (polyethylene terephthalate) film, and organic solvents and the like were dried, whereby the third adhesive film 3A was obtained. In addition, the third adhesive film 3A was coated so that the thickness after drying became 1 μm.

[0176] [Table 3]

[0177]

[0178] (Examples 1 to 8 and Comparative Examples 1 to 5)

[0179] [Production of Adhesive Film]

[0180] The first adhesive film, the second adhesive film, and the third adhesive film produced above were used to produce adhesive films having the structures shown in Tables 4 and 5. For example, in the adhesive film of Example 1, the first adhesive film 1A was bonded to the second adhesive film 2A while applying a temperature of 50 to 60°C, and the release film of the first adhesive film 1A was peeled off. Then, the third adhesive film 3A was bonded to the first adhesive film 1A exposed by peeling off the release film while applying a temperature of 50 to 60°C, and the adhesive film of Example 1 was obtained. Regarding the three-layer adhesive films of Examples 2 to 4, Example 7, and Comparative Examples 3 and 5, adhesive films having the structures shown in Tables 4 and 5 were produced in the same manner as in Example 1. Regarding the two-layer adhesive films of Examples 5, 6, 8, and Comparative Examples 1, 2, and 4, the third adhesive film was not bonded, and except for this, adhesive films having the structures shown in Tables 4 and 5 were produced in the same manner as in Example 1.

[0181] [Measurement of the Thickness of Each Adhesive Layer in the Adhesive Film]

[0182] Regarding the adhesive films of Examples 1 to 8 and Comparative Examples 1 to 5, the thicknesses of the first adhesive layer, the second adhesive layer, and the third adhesive layer were measured. In the measurement, the adhesive film was sandwiched between two glasses (thickness: about 1 mm), and after casting a resin composition composed of 100 g of bisphenol A type epoxy resin (trade name: JER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a curing agent (trade name: Epomount curing agent, manufactured by Refine Tec Ltd.), cross-section grinding was performed using a grinding machine, and the thicknesses of the first adhesive layer, the second adhesive layer, and the third adhesive layer were measured using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-Tech Science Corporation). The results are shown in Tables 4 and 5.

[0183] [Measurement of the Conductive Particle Density]

[0184] Regarding the adhesive films of Examples 1 to 8 and Comparative Examples 1 to 5, using a microscope and image analysis software (trade name: ImagePro, manufactured by Hakuto Co., Ltd.), the number of conductive particles was actually measured at 20 locations per 25000 μm 2 , and its average value was converted to the number of conductive particles per 1 mm 2 , and the conductive particle density was obtained. The results are shown in Tables 4 and 5.

[0185] [Evaluation of the Capture Rate of Conductive Particles and Evaluation of the Connection Resistance]

[0186] (Preparation of Circuit Components)

[0187] As the first circuit component, a circuit component was prepared in which a line pattern of Ti (50 nm) / Al (400 nm) (pattern width: 19 μm, electrode space: 5 μm) was formed on the surface of a polyimide substrate (200H, manufactured by DU PONT-TORAY CO., LTD., outer shape: 38 mm × 28 mm, thickness: 0.05 mm). As the second circuit component, an IC chip (outer shape: 0.9 mm × 20.3 mm, thickness: 0.3 mm, size of bump electrodes: 70 μm × 12 μm, space between bump electrodes: 12 μm, thickness of bump electrodes: 9 μm) in which bump electrodes were arranged in two rows in a staggered manner was prepared.

[0188] (Fabrication of Circuit Connection Structure)

[0189] Circuit connection structures were fabricated using the adhesive films of Examples 1 to 8 and Comparative Examples 1 to 5. The adhesive film was placed on the first circuit component such that the first adhesive layer or the third adhesive layer of the adhesive film was in contact with the first circuit component. Using a thermocompression bonding apparatus (BS-17U, manufactured by OHASHI ENGINEERING Co., Ltd.) composed of a stage including a ceramic heater and a tool (8 mm × 50 mm), heating and pressing were performed at 70°C and 0.98 MPa (10 kgf / cm 2 ) for 2 seconds to bond the adhesive film to the first circuit component, and the release film on the side of the adhesive film opposite to the first circuit component was peeled off. Subsequently, after aligning the positions of the bump electrodes of the first circuit component and the circuit electrodes of the second circuit component, heating and pressing were performed at a measured maximum temperature of 170°C of the adhesive film and a pressure converted per unit area on the bump electrodes of 30 MPa for 5 seconds to bond the second adhesive layer of the adhesive film to the second circuit component, thereby fabricating a circuit connection structure.

[0190] (Evaluation of capture rate of conductive particles)

[0191] In the circuit connection structures obtained using the adhesive films of Examples 1 to 8 and Comparative Examples 1 to 5, the capture rate of conductive particles between the bump electrodes and the circuit electrodes was evaluated. Here, the capture rate of conductive particles is defined as the ratio of the density of conductive particles on the bump electrodes to the density of conductive particles in the adhesive film, and was calculated according to the following formula. Also, regarding the average number of conductive particles on the bump electrodes, by observing the encapsulated circuit components from the polyimide substrate using a differential interference microscope, the number of captured conductive particles per bump was measured and determined via the metal electrodes. A case where the capture rate of conductive particles was 80% or more was evaluated as an "S" determination, a case where the capture rate of conductive particles was 60% or more was evaluated as an "A" determination, and a case where the capture rate of conductive particles was less than 60% was evaluated as a "B" determination. The results are shown in Tables 4 and 5.

[0192] Capture rate of conductive particles (%) = (Average number of conductive particles on bump electrodes / (Bump electrode area × Density of conductive particles in adhesive film)) × 100

[0193] (Evaluation of connection resistance)

[0194] The connection resistance was evaluated using the circuit connection structures obtained from the adhesive films of Examples 1 to 8 and Comparative Examples 1 to 5. Regarding the evaluation of the connection resistance, it was carried out by the four-terminal measurement method, and the evaluation was performed using the average value of the connection resistance values measured at 14 sites. A multimeter (MLR21, manufactured by ETAC) was used in the measurement. A case where the connection resistance value was less than 0.6 Ω was evaluated as an "S" determination, a case where the connection resistance value was less than 1.0 Ω was evaluated as an "A" determination, and a case where the connection resistance value was 1.0 Ω or more was evaluated as a "B" determination. The results are shown in Tables 4 and 5.

[0195] [Table 4]

[0196]

[0197] [Table 5]

[0198]

[0199] As shown in Tables 4 and 5, the adhesive films of Examples 1 to 8 were excellent in both the capture rate of conductive particles and the connection resistance in the COP package under low pressure. On the other hand, the adhesive films of Comparative Examples 1 to 5 were insufficient in at least one of the capture rate of conductive particles or the connection resistance. From this, it was confirmed that the adhesive film of the present invention can improve the capture rate of conductive particles between the opposing electrodes of the circuit connection structure and can reduce the connection resistance even in the case of encapsulation under low pressure.

[0200] Symbol Explanation

[0201] 1 - First adhesive layer, 2 - Second adhesive layer, 4 - Conductive particles, 5 - Adhesive component, 10 - Adhesive film for circuit connection (adhesive film), 11 - First circuit board, 12 - First electrode (circuit electrode), 13 - First circuit component, 14 - Second circuit board, 15 - Second electrode (bump electrode), 16 - Second circuit component, 17 - Circuit connection portion, 20 - Circuit connection structure.

Claims

1. An adhesive film for circuit connection, comprising: A first adhesive layer containing conductive particles, a cured product of a photocurable resin component, and a first thermosetting resin component; and A second adhesive layer provided on the first adhesive layer and containing a second thermosetting resin component, The thickness of the first adhesive layer is 5 μm or less, The first thermosetting resin component and the second thermosetting resin component contain a cationically polymerizable compound and a thermal cationic polymerization initiator, The photocurable resin component contains a radically polymerizable compound, The cationically polymerizable compound contains both an oxetane compound and an alicyclic epoxy compound.

2. The adhesive film for circuit connection according to claim 1, wherein The thermal cationic polymerization initiator is a salt compound having an anion containing boron as a constituent element.

3. The adhesive film for circuit connection according to claim 1 or 2, further comprising a third adhesive layer provided on the side of the first adhesive layer opposite to the second adhesive layer and containing a third thermosetting resin component.

4. The adhesive film for circuit connection according to claim 3, wherein The third thermosetting resin component contains a cationically polymerizable compound and a thermal cationic polymerization initiator.

5. A method for manufacturing a circuit connection structure, comprising the steps of: interposing the adhesive film for circuit connection according to any one of claims 1 to 4 between a first circuit component having a first electrode and a second circuit component having a second electrode, thermocompression bonding the first circuit component and the second circuit component, and electrically connecting the first electrode and the second electrode to each other.

6. A circuit connection structure, comprising: A first circuit component having a first electrode; A second circuit component having a second electrode; and A circuit connection portion disposed between the first circuit component and the second circuit component, electrically connecting the first electrode and the second electrode to each other, The circuit connection portion contains a cured product of the adhesive film for circuit connection according to any one of claims 1 to 4.

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