Circuit connection adhesive film, circuit connection structure and producing method thereof

Abstract

To provide a circuit connection adhesive film capable of sufficiently reducing connection resistance, a circuit connection structure using the circuit connection adhesive and a method for producing the circuit connection structure.SOLUTION: An adhesive film for circuit connection contains a radical-polymerizable compound, a polymerization initiator, and conductive particles, wherein the radical-polymerizable compound contains a radical-polymerizable compound A having an aromatic ring, and the aromatic ring has multiple hydroxyl groups. A circuit connection structure comprises: a first circuit member having a first electrode; a second circuit member having a second electrode; and a circuit connection portion disposed between the first circuit member and the second circuit member, and electrically connecting the first electrode and the second electrode to each other, wherein the circuit connection portion includes a cured product of the adhesive film for circuit connection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, liquid crystal display panels, organic EL panels, etc. have been used as various display means in televisions, PC monitors, mobile phones, smartphones, etc. In these display devices, from the viewpoints of fine pitch, light weight and thinness, so-called COG (chip on glass) mounting is adopted, in which a driving IC is mounted directly on the glass substrate of the display panel.

[0003] In a liquid crystal display panel employing the COG mounting method, for example, a semiconductor element such as a liquid crystal driving IC is connected to a transparent substrate (such as a glass substrate) having a plurality of transparent electrodes (such as ITO (indium tin oxide)). An anisotropically conductive circuit connection adhesive film, in which conductive particles are dispersed in the adhesive, is used as an adhesive material for connecting the electrode terminals of the semiconductor element to the transparent electrodes. For example, when a liquid crystal driving IC is mounted as the semiconductor element, the liquid crystal driving IC has a plurality of electrode terminals on its mounting surface corresponding to the transparent electrodes, and the electrode terminals and the transparent electrodes are connected by thermocompression bonding the liquid crystal driving IC onto the transparent substrate via the anisotropically conductive circuit connection adhesive film, thereby obtaining a circuit connection structure.

[0004] In recent years, displays with curved surfaces (flexible displays), such as POELD (Plasitic Organic Electro-Luminescence Diode) displays, have been proposed. In such flexible displays, flexible plastic substrates (such as polyimide substrates) are used instead of glass substrates, and various electronic components, such as driving ICs, are also mounted on the plastic substrates. As a mounting method for such displays, chip-on-plastic (COP) mounting, which uses an anisotropically conductive circuit-connecting adhesive film, has been investigated (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

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

[0006] In current-driven OLEDs, there is a need to further reduce the connection resistance between opposing electrodes. Known methods for reducing the connection resistance of circuit connection structures include adjusting the particle hardness of conductive particles and lowering the minimum melt viscosity of adhesive films in order to improve contact between the electrodes and conductive particles. However, these methods alone make it difficult to obtain circuit connection structures that are resistant to increases in connection resistance even after reliability testing through short-time mounting.

[0007] Therefore, one aspect of the present invention aims to provide an adhesive film for circuit connection that can sufficiently reduce connection resistance, and another aspect of the present invention aims to provide a circuit connection structure using the adhesive film for circuit connection and a method for producing the circuit connection structure. [Means for solving the problem]

[0008] The present invention includes, for example, the following [1] to

[11] . [1] A composition comprising a radical polymerizable compound, a polymerization initiator, and conductive particles, the radical polymerizable compound contains a radical polymerizable compound A having an aromatic ring, An adhesive film for circuit connection, wherein the aromatic ring has a plurality of hydroxy groups. [2] the plurality of hydroxy groups has a first hydroxy group and a second hydroxy group; the first hydroxy group is bonded to a carbon atom constituting the aromatic ring, The adhesive film for circuit connection according to [1], wherein the second hydroxy group is bonded to a carbon atom adjacent to the carbon atom. [3] The adhesive film for circuit connection according to [1] or [2], wherein the aromatic ring is represented by the following general formula (X): [ka] [In formula (X), * indicates a bonding position, and R 1 ~R 4 represents a hydrogen atom or a hydroxy group, and R 1 ~R 4 At least one of the groups represents a hydroxy group. [4] The adhesive film for circuit connection according to any one of [1] to [3], wherein the radically polymerizable compound A is a pyrogallol methacrylate compound. [5] A first adhesive layer and a second adhesive layer laminated on the first adhesive layer, The adhesive film for circuit connection according to any one of [1] to [4], wherein at least one of the first adhesive layer and the second adhesive layer contains the radical polymerizable compound A. [6] The adhesive film for circuit connection according to any one of [1] to [5], wherein the radical polymerizable compound further comprises a (poly)urethane (meth)acrylate compound. [7] An adhesive film for circuit connection according to claim 1, further containing a thermoplastic resin. [8] The adhesive film for circuit connection according to any one of [1] to [7], further comprising a coupling agent. [9] The adhesive film for circuit connection according to any one of [1] to [8], further comprising a filler.

[10] a first circuit member having a first electrode; a second circuit member having a second electrode; a circuit connection portion disposed between the first circuit member and the second circuit member, electrically connecting the first electrode and the second electrode to each other; Equipped with A circuit connection structure, wherein the circuit connection portion comprises a cured product of the adhesive film for circuit connection according to any one of [1] to [9].

[11] A step of preparing a first circuit member having a first electrode, a second circuit member having a second electrode, and a substrate-attached adhesive film for circuit connection, which comprises, on a substrate, the adhesive film for circuit connection according to any one of [1] to [9]; transferring the adhesive film for circuit connection from the substrate onto a surface of the first circuit member on which the first electrode is formed; a step of arranging the first circuit member, the adhesive film for circuit connection, and the second circuit member in this order so that the first electrode and the second electrode face each other, and then thermocompressing the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other; A method for manufacturing a circuit connection structure, comprising: [Effects of the Invention]

[0009] The present invention can provide an adhesive film for circuit connection that can sufficiently reduce connection resistance, and can also provide a circuit connection structure that uses the adhesive film for circuit connection and a method for producing the circuit connection structure. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a schematic cross-sectional view showing an adhesive film for circuit connection according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a circuit connection structure according to one embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a manufacturing process of a circuit connection structure according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification, a numerical range indicated with "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the Examples. Furthermore, the upper and lower limits individually described can be arbitrarily combined. Furthermore, 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." Furthermore, "(poly)" refers to both the presence and absence of the "poly" prefix. Furthermore, "A or B" may include either A or B, or may include both. Furthermore, the materials exemplified below may be used alone or in combination of two or more, unless otherwise specified. When a composition contains multiple substances corresponding to each component, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings where necessary, but the present invention is not limited to the following embodiments.

[0013] <Adhesive film for circuit connection> Figure 1 is a schematic cross-sectional view showing an adhesive film for circuit connection of one embodiment. As shown in Figure 1, the adhesive film for circuit connection 1 (hereinafter also simply referred to as "adhesive film 1") comprises a first adhesive layer 2 and a second adhesive layer 3 laminated on the first adhesive layer 2.

[0014] (First adhesive layer) The first adhesive layer 2 is made of a cured product of an adhesive composition (first adhesive composition). The adhesive composition contains (A) a radically polymerizable compound (hereinafter also referred to as "component (A)"), (B) a polymerization initiator (hereinafter also referred to as "component (B)"), and (C) conductive particles (hereinafter also referred to as "component (C)").

[0015] The first adhesive layer 2 is obtained, for example, by irradiating a layer made of an adhesive composition with light energy to polymerize component (A) and cure (photocure) the adhesive composition. That is, the first adhesive layer 2 comprises, for example, conductive particles 4 and an adhesive component 5 obtained by curing the components of the adhesive composition other than the conductive particles 4. The adhesive component 5 includes, for example, a radical polymer of component (A). The adhesive component 5 may or may not contain unreacted components (A) and (B).

[0016] [Component (A): Radical polymerizable compound] Component (A) is a compound that polymerizes, for example, by radicals generated by a photopolymerization initiator upon irradiation with light (e.g., ultraviolet light). Component (A) may be a monomer, oligomer, or polymer. As component (A), one type of compound may be used alone, or multiple types of compounds may be used in combination.

[0017] Component (A) has at least one polymerizable group. The polymerizable group may be a radically polymerizable group that reacts with radicals, from the viewpoint of further improving the effect of reducing connection resistance and achieving more excellent connection reliability. Examples of the radically polymerizable group include a vinyl group, an allyl group, a styryl group, an alkenyl group, an alkenylene group, a (meth)acryloyl group, an acrylamide group, and a maleimide group.

[0018] The number of polymerizable groups in component (A) may be 2 or more from the viewpoint of easily obtaining the physical properties and crosslink density necessary for reducing connection resistance after polymerization, and may be 10 or less from the viewpoint of suppressing cure shrinkage during polymerization. Suppressing cure shrinkage during polymerization is preferable because it allows a uniform and stable film (first adhesive layer) to be obtained after light irradiation. In this embodiment, in order to balance the crosslink density and cure shrinkage, a polymerizable compound having the number of polymerizable groups within the above range may be used, and then a polymerizable compound having the number of polymerizable groups outside the above range may be additionally used.

[0019] Specific examples of the component (A) include (meth)acrylate compounds, maleimide compounds, vinyl ether compounds, allyl compounds, styrene and its derivatives, acrylamide compounds and its derivatives, nadimide derivatives, natural rubber, isoprene rubber, butyl rubber, nitrile rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and carboxylated nitrile rubber.

[0020] Examples of (meth)acrylate compounds include epoxy (meth)acrylate, (poly)urethane (meth)acrylate, methyl (meth)acrylate, polyether (meth)acrylate, polyester (meth)acrylate, polybutadiene (meth)acrylate, silicone acrylate, ethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-hexyl (meth)acrylate. Acrylate, 2-hydroxyethyl (meth)acrylate, isopropyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobutyl (meth)acrylate, isobornyl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, n-lauryl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-(meth)acryloyloxyethyl phosphate, N,N-dimethyl Cetylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, polyethylene glycol di(meth)acrylate, polyalkylene glycol di(meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, neo Pentyl glycol di(meth)acrylate, pentaerythritol (meth)acrylate, dipentaerythritol hexa(meth)acrylate, isocyanuric acid modified bifunctional (meth)acrylate, isocyanuric acid modified trifunctional (meth)acrylate, tricyclodecanyl acrylate, dimethylol-tricyclodecane diacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane, 2,Examples include 2-di(meth)acryloyloxydiethyl phosphate and 2-(meth)acryloyloxyethyl acid phosphate.

[0021] Examples of the maleimide compound include 1-methyl-2,4-bismaleimidebenzene, N,N'-m-phenylene bismaleimide, N,N'-p-phenylene bismaleimide, N,N'-m-toluylene bismaleimide, N,N'-4,4-biphenylene bismaleimide, N,N'-4,4-(3,3'-dimethyl-biphenylene) bismaleimide, N,N'-4,4-(3,3'-dimethyldiphenylmethane) bismaleimide, N,N'-4,4-(3,3'-diethyldiphenylmethane) bismaleimide, N,N'-4,4-diphenylmethane bismaleimide, and N,N'-4,4-diphenylpropane. Examples of suitable bismaleimides include panbismaleimide, N,N'-4,4-diphenyletherbismaleimide, N,N'-3,3-diphenylsulfonebismaleimide, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, 2,2-bis(3-s-butyl-4-8(4-maleimidophenoxy)phenyl)propane, 1,1-bis(4-(4-maleimidophenoxy)phenyl)decane, 4,4'-cyclohexylidene-bis(1-(4maleimidophenoxy)-2-cyclohexyl)benzene, and 2,2'-bis(4-(4-maleimidophenoxy)phenyl)hexafluoropropane.

[0022] Examples of the vinyl ether compound include diethylene glycol divinyl ether, dipropylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, and trimethylolpropane trivinyl ether.

[0023] Examples of the allyl compound include 1,3-diallyl phthalate, 1,2-diallyl phthalate, and triallyl isocyanurate.

[0024] Examples of the acrylamide compound include acrylamide, N,N-methylenebisacrylamide, N-isopropylacrylamide, N-tert-butylacrylamide, N,N-dimethylacrylamide, acryloylmorpholine, hydroxyethylacrylamide, and glycol acrylamide.

[0025] An adhesive film for circuit connection according to one embodiment of the present invention contains, as component (A), a radically polymerizable compound A having an aromatic ring (hereinafter also referred to as "component (A1)"). The aromatic ring of the radically polymerizable compound has multiple hydroxy groups. When the adhesive film for circuit connection comprises a first adhesive layer and a second adhesive layer, at least one of the first adhesive layer and the second adhesive layer contains component (A1).

[0026] The inclusion of component (A1) in the adhesive film for circuit connection allows the connection resistance of the circuit adhesive film to be sufficiently reduced. The inventors speculate that the reason for this is as follows: that is, the inclusion of component (A1) in the adhesive film for circuit connection strengthens cross-linking with other components, thereby sufficiently maintaining the flatness of the conductive particles, thereby reducing the connection resistance. However, the mechanism of the present invention is not limited to the above.

[0027] In this specification, an aromatic ring having multiple hydroxy groups means that a hydroxy group is bonded to a carbon atom constituting the aromatic ring (hereinafter, this carbon atom will also be referred to as "carbon atom X"), and that a hydroxy group is bonded to a carbon atom other than carbon atom X constituting the aromatic ring.

[0028] When the component (A1) has a first hydroxy group and a second hydroxy group as the multiple hydroxy groups, from the viewpoint of making it easier to reduce the connection resistance, the first hydroxy group may be bonded to a carbon atom that constitutes an aromatic ring, and the second hydroxy group may be bonded to a carbon atom adjacent to the first hydroxy group.

[0029] Examples of the aromatic ring contained in the component (A1) include a benzene ring, a naphthalene ring, an anthracene ring, etc. When the component (A1) contains a benzene ring, the aromatic ring contained in the component (A1) may be, for example, one represented by the following general formula (X): [ka] [In formula (X), * indicates a bonding position, and R 1 ~R 4 represents a hydrogen atom or a hydroxy group, and R 1 ~R 4 At least one of the groups represents a hydroxy group.

[0030] From the viewpoint of facilitating a reduction in connection resistance, the number of hydroxy groups in the aromatic ring may be 5 or less, 4 or less, or 3 or less. The number of hydroxy groups in the aromatic ring may be 2 or more, or 3 or more.

[0031] Examples of the component (A1) include catechol compounds, resorcinol compounds, pyrogallol compounds, and phloroglucinol compounds. These compounds have a polymerizable double bond at the end of their structure. Examples of functional groups having a polymerizable double bond include acryloyl groups, methacryloyl groups, acrylamide groups, vinyl groups, and styrene groups. From the viewpoint of facilitating a reduction in connection resistance, the component (A1) may be a catechol compound or a pyrogallol compound.

[0032] The molecular weight of the component (A1) may be 200 or more, 250 or more, or 300 or more from the viewpoint of making it easier to reduce the connection resistance, and from the same viewpoint, may be 500 or less, 400 or less, or 350 or less.

[0033] From the viewpoint of making it easier to reduce connection resistance, the melting point of the (A1) component may be 0°C or higher, 50°C or higher, 100°C or higher, or 140°C or higher, or may be 250°C or lower, 200°C or lower, or 150°C or lower.

[0034] The component (A1) may be a (meth)acrylate compound or an acrylamide compound, from the viewpoint of making it easier to reduce the connection resistance.

[0035] The component (A1) may or may not have functional groups other than radically polymerizable groups, such as hydroxyl groups, carboxyl groups, and amino groups.

[0036] Examples of the (A1) component include catechol acrylate compounds (compounds having a catechol group and an acryloyl group), pyrogallol acrylate compounds (compounds having a pyrogallol group and an acryloyl group), catechol methacrylate compounds (compounds having a catechol group and a methacryloyl group), pyrogallol methacrylate compounds (compounds having a pyrogallol group and a methacryloyl group), catechol acrylamide compounds (compounds having a catechol group and an acrylamide group), and pyrogallol acrylamide compounds (compounds having a pyrogallol group and an acrylamide group). More specifically, examples include Blenmer GA-MA (compound represented by the following formula (2)) manufactured by NOF Corporation and Dopamine Acrylamide (compound represented by the following formula (3)) manufactured by Osaka Organic Chemical Industry Co., Ltd. [ka] [ka]

[0037] The adhesive film for circuit connection according to another embodiment of the present invention may further contain, as component (A), a radically polymerizable compound (hereinafter also referred to as "component (A2)") that does not fall under component (A1).

[0038] The component (A2) may be any radically polymerizable compound among the above-mentioned radically polymerizable compounds that does not fall under the category of the component (A1). The component (A2) may contain a (poly)urethane (meth)acrylate compound from the viewpoints of achieving both cohesive strength for reducing connection resistance and elongation for improving adhesive strength, and of achieving superior transferability and adhesive properties.

[0039] The component (A2) may contain a (meth)acrylate compound (a (meth)acrylate compound having a phosphate ester structure) represented by the following formula (1): In this case, the adhesive strength to the surface of inorganic materials (such as metals) is improved, making it suitable for bonding electrodes (for example, circuit electrodes). [ka] In formula (1), n ​​represents an integer of 1 to 3, and R represents a hydrogen atom or a methyl group.

[0040] The (meth)acrylate compound represented by formula (1) can be obtained, for example, by reacting phosphoric anhydride with 2-hydroxyethyl (meth)acrylate. Specific examples of the (meth)acrylate compound represented by formula (1) include mono(2-(meth)acryloyloxyethyl) acid phosphate and di(2-(meth)acryloyloxyethyl) acid phosphate.

[0041] The content of component (A1) in component (A) may be 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, or 0.6% by mass or more, based on the total mass of component (A), from the viewpoint of more easily reducing connection resistance, and may be 50% by mass or less, 30% by mass or less, 15% by mass or less, 10% by mass or less, or 7% by mass or less, from the viewpoint of more easily suppressing an increase in connection resistance due to a decrease in fluidity during mounting. From these viewpoints, the content of component (A1) in component (A) may be 0.1 to 50% by mass, 0.3 to 30% by mass, or 0.5 to 15% by mass. The content of component (A1) in component (A) may be 1% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, 5% by mass or more, or 6% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less, based on the total mass of component (A).

[0042] From the viewpoint of making it easier to reduce connection resistance, the content of component (A2) in component (A) may be 99.9% by mass or less, 99.7% by mass or less, or 99.5% by mass or less, based on the total mass of component (A), and from the same viewpoint, it may be 50% by mass or more, 70% by mass or more, or 90% by mass or more. The content of component (A2) in component (A) may be 99% by mass or less, 98% by mass or less, 97% by mass or less, 96% by mass or less, or 95% by mass or less, based on the total mass of component (A), or may be 91% by mass or more, 92% by mass or more, 93% by mass or more, or 94% by mass or more.

[0043] From the viewpoint of making it easier to reduce connection resistance, the content of the (poly)urethane (meth)acrylate compound may be, for example, 60 mass % or more, 70 mass % or more, or 80 mass % or more, and may be 95 mass % or less, 90 mass % or less, or 85 mass % or less, or may be 60 to 95 mass %, 70 to 90 mass %, or 80 to 85 mass %, based on the total mass of the component (A).

[0044] From the viewpoint of further improving the adhesive strength to the surface of an inorganic material (such as a metal) and further improving the adhesive strength between electrodes (for example, between circuit electrodes), the content of the (meth)acrylate compound represented by formula (1) may be, for example, 0.1 mass % or more, 1 mass % or more, or 2 mass % or more, and may be 20 mass % or less, 10 mass % or less, or 5 mass % or less, or may be 0.1 to 20 mass %, 1 to 10 mass %, or 2 to 5 mass %, based on the total mass of component (A).

[0045] The content of component (A) may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more, based on the solid content of the adhesive composition, from the viewpoint of further reducing connection resistance and further suppressing the flow of conductive particles. The content of component (A) may be, for example, 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass, based on the solid content of the adhesive composition, from the viewpoint of suppressing cure shrinkage during polymerization and achieving even better transferability. From these viewpoints, the content of component (A) may be, for example, 5 to 90% by mass, 10 to 80% by mass, 20 to 70% by mass, 30 to 60% by mass, or 40 to 60% by mass, based on the solid content of the adhesive composition.

[0046] The content of component (A) may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more, based on the total solid content of the adhesive composition other than the conductive particles, from the viewpoint of further reducing connection resistance and further suppressing the flow of the conductive particles. The content of component (A) may be, for example, 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass, based on the total solid content of the adhesive composition other than the conductive particles, from the viewpoint of suppressing cure shrinkage during polymerization and achieving even better transferability. From these viewpoints, the content of component (A) may be, for example, 5 to 90% by mass, 10 to 80% by mass, 20 to 70% by mass, 30 to 60% by mass, or 40 to 60% by mass, based on the total solid content of the adhesive composition other than the conductive particles.

[0047] [Component (B): Polymerization initiator] The component (B) may be a photopolymerization initiator (hereinafter also referred to as "component (B1)") or a thermal polymerization initiator (hereinafter also referred to as "component (B2)"). The component (B) may contain the components (B1) and (B2).

[0048] The component (B1) is a photopolymerization initiator (a photoradical polymerization initiator, a photocationic polymerization initiator, or a photoanionic polymerization initiator) that generates radicals, cations, or anions upon irradiation with light having a wavelength in the range of 150 to 750 nm, preferably light having a wavelength in the range of 254 to 405 nm, and more preferably light having a wavelength of 365 nm (e.g., ultraviolet light). The component (B1) may be a photoradical polymerization initiator, from the viewpoint of facilitating curing at low temperatures in a short time. As the component (B1), one compound may be used alone, or multiple compounds may be used in combination.

[0049] Photoradical polymerization initiators decompose when exposed to light to generate free radicals. In other words, photoradical polymerization initiators are compounds that generate radicals when exposed to external light energy. Examples of photoradical polymerization initiators include photopolymerization initiators having an oxime ester structure, a bisimidazole structure, an acridine structure, an α-aminoalkylphenone structure, an aminobenzophenone structure, an N-phenylglycine structure, an acylphosphine oxide structure, a benzyl dimethyl ketal structure, an α-hydroxyalkylphenone structure, and the like.

[0050] From the viewpoint of further improving the effect of suppressing the flow of conductive particles and the effect of suppressing peeling after transfer, a photopolymerization initiator having a structure represented by the following formula (I) may be used as component (B): The photopolymerization initiator may have a plurality of structures represented by the above formula (I). [ka]

[0051] The structure represented by formula (I) may be an oxime ester structure, a bisimidazole structure, or an acridine structure. That is, the adhesive composition may contain a photopolymerization initiator having at least one structure selected from the group consisting of an oxime ester structure, a bisimidazole structure, and an acridine structure as the structure represented by formula (I). Among these, when a photopolymerization initiator having an oxime ester structure is used, the effect of suppressing the flow of conductive particles and the effect of suppressing peeling after transfer tend to be further improved.

[0052] Among compounds having an oxime ester structure, when a compound having a structure represented by the following formula (VI) is used, the above effect tends to be more pronounced. [ka] In formula (VI), R 11 , R 12 and R 13 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an organic group containing an aromatic hydrocarbon group.

[0053] Specific examples of compounds having an oxime ester structure include 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(o-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime), and the like.

[0054] Examples of compounds having a bisimidazole structure include 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-phenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer.

[0055] Examples of compounds having an acridine structure include 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane.

[0056] The content of the photopolymerization initiator having the structure represented by formula (I) may be, for example, 0.1 mass % or more, 0.2 mass % or more, 0.3 mass % or more, or 0.4 mass % or more, based on the total amount of components in the adhesive composition, from the viewpoint of further improving the effect of suppressing the flow of conductive particles. The content of the photopolymerization initiator having the structure represented by formula (I) may be, for example, 1 mass % or less, 0.7 mass % or less, or 0.5 mass % or less, based on the total amount of components in the adhesive composition, from the viewpoint of further improving the effect of suppressing peeling after transfer. From these viewpoints, the content of the photopolymerization initiator having the structure represented by formula (I) may be, for example, 0.1 to 1 mass %, 0.2 to 1 mass %, 0.3 to 0.7 mass %, or 0.4 to 0.5 mass %, based on the total amount of components in the adhesive composition.

[0057] The content of the photopolymerization initiator having the structure represented by formula (I) may be, for example, 0.1 mass% or more, 0.3 mass% or more, 0.4 mass% or more, 0.5 mass% or more, or 0.55 mass% or more, based on the total amount of components other than the conductive particles in the adhesive composition, from the viewpoint of further improving the effect of suppressing flow of the conductive particles. The content of the photopolymerization initiator having the structure represented by formula (I) may be, for example, 1.2 mass% or less, 0.9 mass% or less, or 0.6 mass% or less, based on the total amount of components other than the conductive particles in the adhesive composition, from the viewpoint of further improving the effect of suppressing peeling after transfer. From these viewpoints, the content of the photopolymerization initiator having the structure represented by formula (I) may be, for example, 0.1 to 1.2 mass%, 0.3 to 1.2 mass%, 0.4 to 0.9 mass%, or 0.5 to 0.6 mass%, based on the total amount of components other than the conductive particles in the adhesive composition.

[0058] The component (B2) may be a thermal polymerization initiator that generates radicals, cations, or anions by heat (a thermal radical polymerization initiator, a thermal cationic polymerization initiator, or a thermal anionic polymerization initiator). The component (B2) may be a thermal radical polymerization initiator, from the viewpoint of further improving the effect of reducing connection resistance and achieving more excellent connection reliability. As the component (B2), one compound may be used alone, or multiple compounds may be used in combination.

[0059] A thermal radical polymerization initiator decomposes under heat to generate free radicals. That is, a thermal radical polymerization initiator is a compound that generates radicals upon application of external thermal energy. The thermal radical polymerization initiator can be arbitrarily selected from conventionally known organic peroxides and azo compounds. The thermal radical polymerization initiator may be an organic peroxide from the viewpoint of further improving the effect of suppressing the flow of conductive particles and the effect of suppressing peeling after transfer. Alternatively, from the viewpoint of improving stability, reactivity, and compatibility, the thermal radical polymerization initiator may be an organic peroxide having a one-minute half-life temperature of 90 to 175°C and a weight-average molecular weight of 180 to 1000. When the one-minute half-life temperature of the organic peroxide is within the above range, the storage stability tends to be even better, and sufficiently high radical polymerization property can be obtained, enabling curing in a short time.

[0060] Specific examples of the component (B2) include 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, cumyl peroxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, and t-butyl peroxyneodecanoate. Pivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate, di-t-butylperoxyhexahydroterephthalate, t-amylperoxy-3,5, 5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, t-amylperoxyneodecanoate, di(3-methylbenzoyl) peroxide, dibenzoyl peroxide, di(4-methylbenzoyl) peroxide, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2, organic peroxides such as 5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxybenzoate, dibutyl peroxytrimethyl adipate, t-amyl peroxy normal octoate, t-amyl peroxy isononanoate, and t-amyl peroxybenzoate;Examples of azo compounds include 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis(1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanovaleric acid), and 1,1'-azobis(1-cyclohexanecarbonitrile);

[0061] The content of component (B2) may be 0.5% by mass or more, 1% by mass or more, 1.5% by mass or more, or 2% by mass or more, based on the total amount of components in the adhesive composition, from the viewpoint of excellent fast-curing properties, and further improving the effect of suppressing the flow of conductive particles and the effect of suppressing peeling after transfer. From the viewpoint of pot life, the content of component (B2) may be, for example, 5% by mass or less, 3.5% by mass or less, or 2.5% by mass or less, based on the total amount of components in the adhesive composition. From these viewpoints, the content of component (B2) may be, for example, 0.5 to 5% by mass, 1 to 5% by mass, 1.5 to 3.5% by mass, or 2 to 2.5% by mass, based on the total amount of components in the adhesive composition.

[0062] The content of component (B2) may be, for example, 0.5% by mass or more, 1.5% by mass or more, or 2.5% by mass or more, based on the total amount of components other than the conductive particles in the adhesive composition, from the viewpoint of excellent fast-curing properties, and further improving the effect of suppressing the flow of conductive particles and the effect of suppressing peeling after transfer. From the viewpoint of pot life, the content of component (B2) may be, for example, 20% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total amount of components other than the conductive particles in the adhesive composition. From these viewpoints, the content of component (B2) may be, for example, 0.5 to 20% by mass, 1.5 to 10% by mass, or 2 to 5% by mass, based on the total amount of components other than the conductive particles in the adhesive composition.

[0063] The content of component (B) (the total content of components (B1) and (B2)) may be, for example, 1% by mass or more, 1.5% by mass or more, 2% by mass or more, or 2.5% by mass or more, based on the total amount of components in the adhesive composition, from the viewpoint of further improving the effect of suppressing flow of conductive particles. The content of component (B) may be, for example, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of components in the adhesive composition, from the viewpoint of further improving the effect of suppressing peeling after transfer. From these viewpoints, the content of component (B) may be, for example, 1 to 20% by mass, 1 to 10% by mass, 1.5 to 5% by mass, or 2.5 to 3% by mass, based on the total amount of components in the adhesive composition.

[0064] The content of component (B) (the total content of components (B1) and (B2)) may be, for example, 1% by mass or more, 2% by mass or more, 2.5% by mass or more, or 3% by mass or more, based on the total amount of components other than the conductive particles in the adhesive composition, from the viewpoint of further improving the effect of suppressing flow of the conductive particles. The content of component (B) may be, for example, 25% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total amount of components other than the conductive particles in the adhesive composition, from the viewpoint of further improving the effect of suppressing peeling after transfer. From these viewpoints, the content of component (B) may be, for example, 1 to 25% by mass, 2 to 15% by mass, 2.5 to 10% by mass, or 3 to 5% by mass, based on the total amount of components other than the conductive particles in the adhesive composition.

[0065] [(C) Component: Conductive particles] Component (C) is not particularly limited as long as it is a conductive particle, and may be, for example, a metal particle composed of a metal such as Au, Ag, Ni, Cu, or solder, or a conductive carbon particle composed of conductive carbon. Component (C) may also be a coated conductive particle comprising a core containing a non-conductive material such as glass, ceramic, or plastic (e.g., polystyrene), and a coating layer containing the metal or conductive carbon that coats the core. Among these, metal particles formed of a heat-fusible metal or coated conductive particles comprising a core containing plastic and a coating layer containing a metal or conductive carbon that coats the core are used, making it easier to deform the cured adhesive composition by applying heat or pressure. Therefore, when electrically connecting electrodes, the contact area between the electrodes and component (C) can be increased, further improving the conductivity between the electrodes.

[0066] Component (C) may be an insulating coated conductive particle comprising the above-mentioned metal particles, conductive carbon particles, or coated conductive particles and an insulating layer containing an insulating material such as resin and coating the surface of the particle. When component (C) is an insulating coated conductive particle, even if the content of component (C) is high, the particle surface is coated with resin, which can prevent short circuits caused by contact between components (C) and can also improve insulation between adjacent electrode circuits. Component (C) can be used alone or in combination of two or more of the above-mentioned various conductive particles.

[0067] The maximum particle size of component (C) must be smaller than the smallest gap between the electrodes (the shortest distance between adjacent electrodes). From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of component (C) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of component (C) may be 50 μm or less, 30 μm or less, or 20 μm or less. From these viewpoints, the maximum particle size of component (C) may be 1.0 to 50 μm, 2.0 to 30 μm, or 2.5 to 20 μm. In this specification, the particle size of 300 random conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the largest value obtained is defined as the maximum particle size of component (C). Note that if component (C) is not spherical, e.g., has protrusions, the particle size of component (C) is defined as the diameter of a circle circumscribing the conductive particle in the SEM image.

[0068] From the viewpoint of excellent dispersibility and conductivity, the average particle size of component (C) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the viewpoint of excellent dispersibility and conductivity, the average particle size of component (C) may be 50 μm or less, 30 μm or less, or 20 μm or less. From these viewpoints, the average particle size of component (C) may be 1.0 to 50 μm, 2.0 to 30 μm, or 2.5 to 20 μm. In this specification, the particle size of 300 random conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the average value of the particle sizes obtained is defined as the average particle size.

[0069] The component (C) may be uniformly dispersed in the first adhesive layer 2. The particle density of the component (C) in the first adhesive layer 2 is preferably 100 pcs / mm 3 from the viewpoint of easily obtaining a stable connection resistance. 2 It may be more than 1000pcs / mm 2 It may be more than 2000pcs / mm 2 The particle density of the component (C) in the first adhesive layer 2 may be 100,000 pcs / mm or more from the viewpoint of improving the insulating properties between adjacent electrodes. 2 May be less than 50,000 pcs / mm 2 It may be less than 10000pcs / mm 2 It may be the following:

[0070] The content of component (C) may be, for example, 5% by mass or more, 15% by mass or more, or 20% by mass or more, based on the total mass of the adhesive composition, from the viewpoint of further improving electrical conductivity. The content of component (C) may be, for example, 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total mass of the adhesive composition, from the viewpoint of easily suppressing short circuits. From these viewpoints, the content of component (C) may be, for example, 5 to 50% by mass, 10 to 40% by mass, or 20 to 30% by mass, based on the total mass of the adhesive composition. The content of component (C) based on the total mass of the cured product of the adhesive composition may be within the above-mentioned range, and the content of component (C) based on the total mass of the first adhesive layer may also be within the above-mentioned range.

[0071] The content of component (C) may be 0.1 vol% or more, 1 vol% or more, or 5 vol% or more, based on the total volume of the cured product of the adhesive composition, from the viewpoint of further improving electrical conductivity. The content of component (C) may be 50 vol% or less, 30 vol% or less, or 20 vol% or less, based on the total volume of the cured product of the adhesive composition, from the viewpoint of easily suppressing short circuits. The content of component (C) based on the total volume of the adhesive composition may be the same as the above-mentioned range, and the content of component (C) based on the total volume of the first adhesive layer may also be the same as the above-mentioned range.

[0072] [Other ingredients] The adhesive composition may further contain other components in addition to the components described above. Examples of other components include a thermoplastic resin, a coupling agent, a filler, a thermosetting resin, etc. These components may be contained in the first adhesive layer 2.

[0073] Examples of thermoplastic resins include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, and acrylic rubber. When the adhesive composition contains a thermoplastic resin, the first adhesive layer can be easily formed. Furthermore, when the adhesive composition contains a thermoplastic resin, stress in the first adhesive layer that occurs when the adhesive composition is cured can be alleviated. Furthermore, when the thermoplastic resin has a functional group such as a hydroxyl group, the adhesiveness of the first adhesive layer is likely to be improved. From this perspective, phenoxy resin may be used as the thermoplastic resin. The content of the thermoplastic resin may be, for example, 5% by mass or more, 80% by mass or less, or 5 to 80% by mass, based on the total amount of components other than the conductive particles in the adhesive composition.

[0074] Examples of coupling agents include silane coupling agents having an organic functional group such as a (meth)acryloyl group, a mercapto group, an amino group, an imidazole group, or an epoxy group; silane compounds such as tetraalkoxysilane; tetraalkoxytitanate derivatives; and polydialkyltitanate derivatives. When the adhesive composition contains a coupling agent, adhesion can be further improved. The content of the coupling agent may be, for example, 0.1% by mass or more and 20% by mass or less, based on the total amount of components other than the conductive particles in the adhesive composition. Note that, in this specification, silane coupling agents having a polymerizable group such as a (meth)acryloyl group are not included in the polymerizable compound.

[0075] The filler may be, for example, a non-conductive filler (for example, non-conductive particles). When the adhesive composition contains a filler, further improvement in connection reliability can be expected. The filler may be either an inorganic filler or an organic filler. Examples of inorganic fillers include inorganic fine particles such as metal oxide fine particles, such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles; and nitride fine particles. Examples of organic fillers include organic fine particles, such as silicone fine particles, methacrylate-butadiene-styrene fine particles, acrylic-silicone fine particles, polyamide fine particles, and polyimide fine particles. These fine particles may have a uniform structure or a core-shell structure. The maximum diameter of the filler may be less than the minimum particle diameter of the conductive particles 4. The content of the filler may be, for example, 1% by volume or more, 30% by volume or less, or 1 to 30% by volume, based on the total volume of the adhesive composition.

[0076] Examples of thermosetting resins include silicone resins, epoxy resins, phenolic resins, cyanate resins, melamine resins, urea resins, thermosetting polyimide resins, and unsaturated polyester resins. The content of the thermosetting resin may be, for example, 0.1 mass % or more and 20 mass % or less based on the total amount of components other than the conductive particles in the adhesive composition.

[0077] The adhesive composition may contain other additives such as softeners, accelerators, anti-degradants, colorants, flame retardants, and thixotropic agents. The content of these additives may be, for example, 0.1 to 10 mass % based on the total amount of components other than the conductive particles in the adhesive composition. These additives may be contained in the first adhesive layer 2.

[0078] The thickness d1 of the first adhesive layer 2 may be appropriately set depending on the height of the electrodes of the circuit components to be bonded, etc. The thickness d1 of the first adhesive layer 2 may be, for example, 0.5 μm or more and 20 μm or less. Note that when a portion of the conductive particles 4 is exposed from the surface of the first adhesive layer 2 (for example, protruding toward the second adhesive layer 3), the distance from the surface 2a of the first adhesive layer 2 opposite the second adhesive layer 3 to the boundary S between the first adhesive layer 2 and the second adhesive layer 3, which is located in the space between adjacent conductive particles 4, 4 (the distance indicated by d1 in FIG. 1), is the thickness of the first adhesive layer 2, and the exposed portions of the conductive particles 4 are not included in the thickness of the first adhesive layer 2. The length of the exposed portions of the conductive particles 4 may be, for example, 0.1 μm or more and 20 μm or less, and may be 0.1 to 20 μm.

[0079] The thickness of the adhesive layer can be measured by the following method. First, the adhesive film is sandwiched between two pieces of glass (thickness: approximately 1 mm). Next, a resin composition consisting of 100 g of bisphenol A epoxy resin (trade name: JER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a curing agent (trade name: Epomount Curing Agent, manufactured by Refine Tech Co., Ltd.) is poured into the mold. The cross section is then polished using a polishing machine, and the thickness of each adhesive layer is measured using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-Tech Science Corporation).

[0080] (Second adhesive layer) The second adhesive layer 3 is made of a cured product of an adhesive composition (second adhesive composition). The adhesive composition contains, for example, the above-mentioned components (A) and (B). The adhesive composition may contain other components, such as a thermoplastic resin, a coupling agent, a filler, a softener, an accelerator, an anti-degradant, a colorant, a flame retardant, and a thixotropic agent. Details of the other components are the same as those of the first adhesive layer 2.

[0081] The second adhesive layer 3 (thermosetting composition) may not contain a photopolymerization initiator, and may not contain conductive particles. The content of the photopolymerization initiator in the second adhesive layer 3 may be, for example, 1% by mass or less or 0% by mass, based on the total mass of the second adhesive layer 3. The content of the conductive particles 4 in the second adhesive layer 3 may be, for example, 1% by mass or less or 0% by mass, based on the total mass of the second adhesive layer.

[0082] The thickness d2 of the second adhesive layer 3 may be appropriately set depending on the height of the electrodes of the circuit component to be bonded, etc. The thickness d2 of the second adhesive layer 3 may be 5 μm or more, 200 μm or less, or may be 5 to 200 μm, from the viewpoint of being able to sufficiently fill the space between the electrodes and seal the electrodes, thereby obtaining better connection reliability. Note that when some of the conductive particles 4 are exposed from the surface of the first adhesive layer 2 (for example, protruding toward the second adhesive layer 3), the thickness of the second adhesive layer 3 is the distance (d2 in FIG. 1 ) from the surface 3a of the second adhesive layer 3 opposite the first adhesive layer 2 side to the boundary S between the first adhesive layer 2 and the second adhesive layer 3, which is located in the space between adjacent conductive particles 4, 4.

[0083] The ratio of the thickness d1 of the first adhesive layer 2 to the thickness d2 of the second adhesive layer 3 (thickness d1 of the first adhesive layer 2 / thickness d2 of the second adhesive layer 3) may be 1 or more, 100 or less, or may be 1 to 100, from the viewpoint of being able to sufficiently fill the space between the electrodes and seal the electrodes, thereby obtaining better reliability.

[0084] The thickness of the adhesive film 1 (the total thickness of all layers constituting the adhesive film 1; in Figure 1, the total thickness d1 of the first adhesive layer 2 and the thickness d2 of the second adhesive layer 3) may be, for example, 5 μm or more, 200 μm or less, or may be 5 to 200 μm.

[0085] In the adhesive film 1, conductive particles 4 are dispersed in the first adhesive layer 2. Therefore, the adhesive film 1 is an anisotropically conductive adhesive film having anisotropic conductivity. The adhesive film 1 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and is used to electrically connect the first electrode and the second electrode to each other by thermocompression bonding the first circuit member and the second circuit member.

[0086] Adhesive film 1 has sufficient transferability, allowing the adhesive film to be transferred in a short time. Furthermore, adhesive film 1 tends to suppress peeling at the interface between the circuit member and the circuit connecting member, which occurs when the circuit connection structure is used in a high-temperature, high-humidity environment.

[0087] Although the adhesive film for circuit connection of this embodiment has been described above, the present invention is not limited to the above embodiment.

[0088] For example, the adhesive film for circuit connection may be composed of two layers, a first adhesive layer and a second adhesive layer, or may be composed of three or more layers, including a layer other than the first adhesive layer and the second adhesive layer (e.g., a third adhesive layer). The third adhesive layer may be a layer having a composition similar to the composition described above for the first adhesive layer or the second adhesive layer, and may be a layer having a thickness similar to the thickness described above for the first adhesive layer or the second adhesive layer.

[0089] Furthermore, although the adhesive film for circuit connection in the above embodiment is an anisotropic conductive adhesive film having anisotropic conductivity, the adhesive film for circuit connection may also be a conductive adhesive film that does not have anisotropic conductivity.

[0090] <Method of manufacturing an adhesive film for circuit connection> The method for producing an adhesive film for circuit connection 1 of this embodiment comprises, for example, a preparation step (first preparation step) of preparing the above-described first adhesive layer 2, and a lamination step of laminating the above-described second adhesive layer 3 on the first adhesive layer 2. The method for producing an adhesive film for circuit connection 1 may further comprise a preparation step (second preparation step) of preparing a second adhesive layer 3. The order in which the first preparation step and the second preparation step are performed is not limited, and either the first preparation step or the second preparation step may be performed first.

[0091] In the first preparation step, the first adhesive layer 2 is prepared, for example, by forming the first adhesive layer 2 on a substrate to obtain a first adhesive film. Specifically, first, components (A), (B), and (C), as well as other components added as needed, are added to a solvent (organic solvent), and each component is dissolved or dispersed by stirring, mixing, kneading, or the like to prepare a varnish composition (varnish-like adhesive composition). The varnish composition is then applied to a release-treated substrate using a knife coater, roll coater, applicator, comma coater, die coater, or the like, and the solvent is then volatilized by heating to form a layer of the adhesive composition on the substrate. Next, the layer of the adhesive composition is irradiated with light to cure (photocure) the adhesive composition, forming a first adhesive layer 2 on the substrate (curing step). This results in a first adhesive film.

[0092] The solvent used in preparing the varnish composition may be a solvent capable of uniformly dissolving or dispersing each component. Examples of such solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, and butyl acetate. These solvents can be used alone or in combination of two or more. The stirring, mixing, and kneading in preparing the varnish composition can be performed using, for example, a mixer, a grinder, a three-roll mill, a ball mill, a bead mill, or a homodisper.

[0093] The substrate is not particularly limited as long as it has heat resistance that can withstand the heating conditions used to volatilize the solvent. For example, substrates (e.g., films) made of oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, etc. can be used.

[0094] The heating conditions for volatilizing the solvent from the varnish composition applied to the substrate may be such that the solvent is sufficiently volatilized, for example, at 40°C or higher and 120°C or lower for 0.1 to 10 minutes.

[0095] A portion of the solvent may remain in the layer made of the adhesive composition without being removed. The content of the solvent in the layer made of the adhesive composition may be, for example, 10 mass % or less based on the total mass of the layer made of the adhesive composition.

[0096] For the light irradiation in the curing step, light having a wavelength in the range of 150 to 750 nm (for example, ultraviolet light) may be used. The light irradiation can be carried out using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, or the like. The amount of light irradiation is not particularly limited, and for example, the integrated light amount of light having a wavelength of 365 nm is 100 mJ / cm. 2 may be 200 mJ / cm or more, 2 may be 300 mJ / cm or more, 2 The amount of light irradiation may be, for example, 10,000 mJ / cm 2 in terms of the integrated light amount of light with a wavelength of 365 nm. 2 may be less than or equal to 5000 mJ / cm 2 may be less than or equal to 3000 mJ / cm 2 It may be the following:

[0097] In the second preparation step, similarly to the first preparation step, the second adhesive layer 3 is prepared by forming the second adhesive layer 3 on the substrate to obtain a second adhesive film.

[0098] A portion of the solvent may remain unremoved in the second adhesive layer 3. The content of the solvent in the second adhesive layer 3 may be, for example, 10 mass % or less based on the total mass of the second adhesive layer 3.

[0099] In the lamination process, the second adhesive layer 3 may be laminated on the first adhesive layer 2 by bonding the first adhesive film and the second adhesive film together, or the second adhesive layer 3 may be laminated on the first adhesive layer 2 by applying a varnish composition used to form the second adhesive layer 3 onto the first adhesive layer 2 and volatilizing the solvent.

[0100] Examples of methods for bonding the first adhesive film and the second adhesive film include hot pressing, roll lamination, vacuum lamination, etc. Lamination may be performed under temperature conditions of, for example, 0 to 80°C.

[0101] <Circuit connection structure and method for manufacturing the same> Hereinafter, a circuit connection structure using the above-mentioned adhesive film for circuit connection 1 as the circuit connecting material and a method for producing the same will be described.

[0102] Fig. 2 is a schematic cross-sectional view showing a circuit connection structure of one embodiment. As shown in Fig. 2, a circuit connection structure 10 includes a first circuit board 11 and a first circuit member 13 having a first electrode 12 formed on a main surface 11a of the first circuit board 11, a second circuit board 14 and a second circuit member 16 having a second electrode 15 formed on a main surface 14a of the second circuit board 14, and a circuit connection portion 17 disposed between the first circuit member 13 and the second circuit member 16 and electrically connecting the first electrode 12 and the second electrode 15 to each other.

[0103] The first circuit member 13 and the second circuit member 16 may be the same or different. The first circuit member 13 and the second circuit member 16 may be a glass or plastic substrate on which electrodes are formed, a printed wiring board, a ceramic wiring board, a flexible wiring board, a semiconductor silicon IC chip, or the like. The first circuit board 11 and the second circuit board 14 may be formed of an inorganic material such as a semiconductor, glass, or ceramic, an organic material such as polyimide or polycarbonate, or a composite material such as glass / epoxy. The first electrode 12 and the second electrode 15 may be formed of gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, titanium, indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), or the like. The first electrode 12 and the second electrode 15 may be circuit electrodes or bump electrodes. At least one of the first electrode 12 and the second electrode 15 may be a bump electrode. In FIG. 2, the second electrode 15 is a bump electrode.

[0104] The circuit connection portion 17 is made of a cured product of the adhesive film 1 described above. The circuit connection portion 17 has, for example, a first region 18 located on the first circuit member 13 side in the direction in which the first circuit member 13 and the second circuit member 16 face each other (hereinafter referred to as the "facing direction") and made of a cured product of components of the adhesive composition other than the conductive particles 4 described above, a second region 19 located on the second circuit member 16 side in the facing direction and made of a cured product of the thermosetting composition described above, and conductive particles 4 interposed between at least the first electrode 12 and the second electrode 15 to electrically connect the first electrode 12 and the second electrode 15 to each other. The circuit connection portion does not have to have two regions like the first region 18 and the second region 19, and may be made of, for example, a cured product in which a cured product of components of the adhesive composition other than the conductive particles 4 described above and a cured product of the thermosetting composition described above are mixed.

[0105] The manufacturing method of the circuit connection structure 10 described above includes, for example, the steps of preparing a first circuit member 13 having a first electrode 12, a second circuit member 16 having a second electrode 15, and a substrate-attached adhesive film (substrate-attached adhesive film for circuit connection) having an adhesive film (adhesive film for circuit connection) 1 on a substrate; transferring (laminating) the adhesive film 1 from the substrate onto the surface of the first circuit member 13 on which the first electrode 12 is formed; and arranging the first circuit member 13, adhesive film 1, and second circuit member 16 in this order so that the first electrode 12 and the second electrode 15 face each other, and then thermocompressing the first circuit member 13 and the second circuit member 16 to electrically connect the first electrode 12 and the second electrode 15 to each other.

[0106] Specifically, first, a first circuit board 11 and a first circuit member 13 having a first electrode 12 formed on the main surface 11a of the first circuit board 11, a second circuit member 16 having a second electrode 15 formed on the main surface 14a of the second circuit board 14, and a substrate-attached adhesive film having an adhesive film 1 on a substrate are prepared. The substrate of the substrate-attached adhesive film may be the substrate used in producing the adhesive film described above.

[0107] Next, the adhesive film 1 is transferred (laminated) from the substrate onto the surface of the first circuit member 13 on which the first electrode 12 is formed. Specifically, for example, the adhesive film 1 is laminated onto the first circuit member 13 so that the first adhesive layer 2 side faces the mounting surface 11a of the first circuit member 13.

[0108] The lamination method is not particularly limited, and a roll laminator, a diaphragm laminator, a vacuum roll laminator, or a vacuum diaphragm laminator can be used. After the pre-lamination, pressure bonding can be performed using a thermocompression bonding device.

[0109] The lamination conditions may be appropriately set depending on the types of laminator, substrate, first circuit member 13, second circuit member 16, etc. used. The temperature during lamination (compression temperature) may be, for example, 50 to 90°C. The pressure during lamination (compression pressure) may be, for example, 0.5 to 1.5 MPa. The lamination time (compression time) may be, for example, 0.5 to 1.5 seconds.

[0110] Next, as shown in FIG. 3(a), a second circuit member 16 is placed on the first circuit member 13 laminated with the adhesive film 1 so that the first electrode 12 and the second electrode 15 face each other.

[0111] Then, as shown in FIG. 3( b), the first circuit member 13, the adhesive film 1, and the second circuit member 16 are heated while the first circuit member 13 and the second circuit member 16 are pressed in the thickness direction, thereby thermocompression-bonding the first circuit member 13 and the second circuit member 16 to each other. At this time, as indicated by the arrows in FIG. 3( b), the second adhesive layer 3 is made of a flowable uncured thermosetting composition. Therefore, the second adhesive layer 3 flows to fill the gaps between the second electrodes 15, 15, and is cured by the heating. As a result, the first electrode 12 and the second electrode 15 are electrically connected to each other via the conductive particles 4, and the first circuit member 13 and the second circuit member 16 are bonded to each other, thereby obtaining the circuit connection structure 10 shown in FIG. 2. In the method for producing the circuit connection structure 10 of this embodiment, the first adhesive layer 2 is a pre-cured layer. Therefore, the conductive particles 4 hardly flow during the thermocompression bonding. Therefore, the conductive particles are efficiently captured between the opposing electrodes, thereby reducing the connection resistance between the opposing electrodes 12 and 15. Therefore, a circuit connection structure with excellent connection reliability can be obtained.

[0112] The temperature and time during thermocompression bonding may be any temperature that can sufficiently cure the adhesive film 1 and bond the first circuit member 13 and the second circuit member 16. The thermocompression bonding temperature may be, for example, 150 to 200° C. The thermocompression bonding time may be, for example, 4 to 7 seconds. [Example]

[0113] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0114] <Synthesis of polyurethane acrylate (UA1)> Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser with a calcium chloride drying tube, and a nitrogen gas inlet tube, 2500 parts by mass (2.50 mol) of poly(1,6-hexanediol carbonate) (trade name: Duranol T5652, manufactured by Asahi Kasei Chemicals Corporation, number average molecular weight 1000) and 666 parts by mass (3.00 mol) of isophorone diisocyanate (manufactured by Sigma-Aldrich) were uniformly added dropwise over 3 hours. Next, after sufficient nitrogen gas was introduced into the reaction vessel, the reaction vessel was heated to 70-75°C and the mixture was allowed to react. Next, 0.53 parts by mass (4.3 mmol) of hydroquinone monomethyl ether (Sigma-Aldrich) and 5.53 parts by mass (8.8 mmol) of dibutyltin dilaurate (Sigma-Aldrich) were added to the reaction vessel, followed by 238 parts by mass (2.05 mol) of 2-hydroxyethyl acrylate (Sigma-Aldrich). The mixture was allowed to react for 6 hours at 70°C under an air atmosphere. This yielded polyurethane acrylate (UA1). The weight-average molecular weight of polyurethane acrylate (UA1) was 15,000. The weight-average molecular weight was measured by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene under the following conditions. (Measurement conditions) Equipment: Tosoh GPC-8020 Detector: Tosoh Corporation RI-8020 Column: Hitachi High-Tech Gelpack GLA160S + GLA150S Sample concentration: 120mg / 3mL Solvent: tetrahydrofuran Injection volume: 60μL Pressure: 2.94 x 10 6 Pa (30 kgf / cm 2 ) Flow rate: 1.00mL / min

[0115] <Preparation of conductive particles> A nickel layer was formed on the surface of the polystyrene particles to a thickness of 0.2 μm, yielding conductive particles with an average particle size of 4 μm, a maximum particle size of 4.5 μm, and a specific gravity of 2.5.

[0116] <Method for preparing polyester urethane resin> 48 parts by mass of isophthalic acid and 37 parts by mass of neopentyl glycol were added to a heated stainless steel autoclave equipped with a stirrer, thermometer, condenser, vacuum generator, and nitrogen gas inlet tube, and 0.02 parts by mass of tetrabutoxy titanate as a catalyst was further added. The mixture was then heated to 220°C under a nitrogen stream and stirred for 8 hours. The pressure was then reduced to atmospheric pressure (760 mmHg) and cooled to room temperature. The white precipitate was then removed, washed with water, and vacuum dried to obtain a polyester polyol.

[0117] The polyester polyol obtained by the reaction of the dicarboxylic acid and diol described above was thoroughly dried, then dissolved in MEK and charged into a four-neck flask equipped with a stirrer, a dropping funnel, a reflux condenser, and a nitrogen gas inlet tube. Furthermore, dibutyltin laurate was added as a catalyst in an amount of 0.05 parts by mass per 100 parts by mass of the polyester polyol, and 4,4'-diphenylmethane diisocyanate dissolved in MEK was added using a dropping funnel in an amount of 50 parts by mass per 100 parts by mass of the polyester polyol, and the mixture was stirred at 80°C for 4 hours to obtain the desired polyester urethane resin.

[0118] <Preparation of First Adhesive Composition and Second Adhesive Composition> A first adhesive composition for forming the first adhesive layer and a second adhesive composition for forming the second adhesive layer were prepared by mixing the components in the amounts (unit: parts by mass) shown in Tables 1 and 2. Details of each component in Table 1 are as follows, and the amount of each component in the table represents the amount of non-volatile content. (Radical polymerizable compound) A1: Methacrylate having a pyrogallol group (trade name: Blenmer GA-MA, a compound represented by the following formula (2), manufactured by NOF Corporation, melting point 147°C) [ka] A2: Dicyclopentadiene diacrylate (trade name: DCP-A, manufactured by Toagosei Co., Ltd.) A3: Polyurethane acrylate (UA1) synthesized as described above A4: 2-Methacryloyloxyethyl acid phosphate (trade name: Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.) A5: Dopamine acrylamide (Osaka Organic Chemical Industry Ltd.) (Photopolymerization initiator) B1: 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(O-benzoyloxime)] (trade name: Irgacure® OXE01, manufactured by BASF) (thermal polymerization initiator) C1: Benzoyl peroxide (product name: Niper BMT-K40, manufactured by NOF Corporation) (conductive particles) D1: Conductive particles prepared as described above (thermoplastic resin) E1: Polyester urethane resin synthesized above (coupling agent) F1: 3-methacryloxypropyltrimethoxysilane (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) (filling material) G1: Silica fine particles (product name: R104, manufactured by Nippon Aerosil Co., Ltd., average particle size (primary particle size): 12 nm) (solvent) H1: Methyl ethyl ketone

[0119] [Table 1]

[0120] [Table 2]

[0121] <Preparation of adhesive film for circuit connection> The first adhesive composition was applied to a 50 μm thick PET film using a coating device. The composition was then dried with hot air at 70°C for 3 minutes to form a layer on the PET film with a thickness of 4 μm (thickness after drying). The thickness was measured using a contact thickness meter. The layer on the PET film was then irradiated with a metal halide lamp at an integrated light intensity of 1500 mJ / cm. 2 The radical polymerizable compound was polymerized by irradiating the film with light so that the layer on the PET film was cured to form a first adhesive layer. The above-described procedure yielded a first adhesive film having a first adhesive layer (thickness of the region where the conductive particles were present: 4 μm) on the PET film.

[0122] The second adhesive composition was applied to a 50 μm thick PET film using a coating device. The film was then dried with hot air at 70°C for 3 minutes to form an 8 μm thick second adhesive layer on the PET film. This procedure resulted in a second adhesive film having a second adhesive layer on the PET film.

[0123] The first adhesive film and the second adhesive film were arranged so that their adhesive layers faced each other, and were laminated together with the PET film substrate using a roll laminator while being heated at 40° C. This produced an adhesive film for circuit connection with a PET film, which had a two-layer structure in which the first adhesive layer and the second adhesive layer were laminated.

[0124] The thickness of the first adhesive layer of the prepared adhesive film for circuit connection was measured by the following method. First, the circuit-connecting adhesive film was sandwiched between two sheets of glass (approximately 1 mm thick) and a resin composition consisting of 100 g of bisphenol A epoxy resin (product name: JER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a curing agent (product name: Epomount Curing Agent, manufactured by Refine Tech Co., Ltd.) was poured into the mold. The cross section was then polished using a polishing machine, and the thickness of the first adhesive layer located between adjacent conductive particles was measured using a scanning electron microscope (SEM, product name: SE-8020, manufactured by Hitachi High-Tech Science Corporation). The thickness of the first adhesive layer was 2 μm.

[0125] <Evaluation> The connection resistance was evaluated using the produced adhesive film for circuit connection. Two types of adhesive film for circuit connection were prepared for the evaluation of connection resistance: an adhesive film for circuit connection immediately after production (untreated adhesive film for circuit connection) and an adhesive film for circuit connection after storage for 3 days in an environment of a temperature of 40°C and a humidity of 20%RH (adhesive film for circuit connection after storage).

[0126] (Preparation of circuit components) The first circuit component was an alkali-free glass substrate (OA-11, manufactured by Nippon Electric Glass Co., Ltd., dimensions: 38 mm × 28 mm, thickness: 0.3 mm) with a three-layer electrode wiring pattern (pattern width: 19 μm, inter-electrode spacing: 5 μm) consisting of AlNd (thickness: 100 nm), Mo (thickness: 50 nm), and ITO (thickness: 100 nm) formed on its surface.The second circuit component was an IC chip (dimensions: 0.9 mm × 20.3 mm, thickness: 0.3 mm, bump electrode size: 70 μm × 12 μm, inter-electrode spacing: 12 μm, bump electrode thickness: 8 μm) with bump electrodes arranged in two rows in a staggered pattern.

[0127] The PET film on the first adhesive layer side of the prepared adhesive film for circuit connection was peeled off, and the adhesive film for circuit connection was placed on the first circuit member. Using a thermocompression bonding device (LD-06, manufactured by Ohashi Manufacturing Co., Ltd.) consisting of a stage made of a ceramic heater and a tool (8 mm × 50 mm), the adhesive film was pressed at 50°C and 0.98 MPa (10 kgf / cm2 ) for 2 seconds to attach the adhesive film for circuit connection to the first circuit member, and then peel off the PET film on the second adhesive layer side of the adhesive film for circuit connection. Next, the circuit electrodes of the first circuit member and the bump electrodes of the second circuit member were aligned, and then the circuit connection structure was produced by heating and pressing for 4 seconds at 180°C and 6 MPa on a base heated to 90°C. Note that the temperature during production of the circuit connection structure indicates the maximum measured temperature of the adhesive film, and the pressure indicates the area-converted pressure at the bump electrodes, converted into the total area of ​​the surfaces of the bump electrodes of the second circuit member facing the first circuit member.

[0128] The connection resistance was measured using a four-terminal measurement method. Two types of circuit connection structures were prepared for the connection resistance measurement: one immediately after fabrication (initial circuit connection structure), and the other after leaving it in a thermo-hygrostat chamber at a temperature of 100°C and a humidity of 85% RH for 32 hours (circuit connection structure after high-temperature, high-humidity treatment). That is, circuit connection structures treated under four different conditions were prepared, and the connection resistance was measured. The connection resistance was measured at 14 points in each circuit connection structure, and the maximum value was taken as the connection resistance value. The measurement results are shown in Tables 3 and 4.

[0129] [Table 3]

[0130] [Table 4] [Explanation of symbols]

[0131] 1...adhesive film for circuit connection, 2...first adhesive layer, 3...second adhesive layer, 4...conductive particles, 10...circuit connection structure, 12...first electrode, 13...first circuit member, 15...second electrode, 16...second circuit member.

Claims

1. A composition comprising a radical polymerizable compound, a polymerization initiator, and conductive particles, the radical polymerizable compound contains a radical polymerizable compound A having an aromatic ring, An adhesive film for circuit connection, wherein the aromatic ring has a plurality of hydroxy groups.

2. the plurality of hydroxy groups comprises a first hydroxy group and a second hydroxy group; the first hydroxy group is bonded to a carbon atom constituting the aromatic ring, 2. The adhesive film for circuit connection according to claim 1, wherein said second hydroxy group is bonded to a carbon atom adjacent to said carbon atom.

3. 2. The adhesive film for circuit connection according to claim 1, wherein the aromatic ring is represented by the following general formula (X): 【Chemistry 1】 [In formula (X), * indicates a bonding position, and R １ ~R ４ represents a hydrogen atom or a hydroxy group, and R １ ~R ４ At least one of these represents a hydroxy group.

4. 2. The adhesive film for circuit connection according to claim 1, wherein the radical polymerizable compound A is a pyrogallol methacrylate compound.

5. a first adhesive layer and a second adhesive layer laminated on the first adhesive layer; 2. The adhesive film for circuit connection according to claim 1, wherein at least one of the first adhesive layer and the second adhesive layer contains the radical polymerizable compound A.

6. 2. The adhesive film for circuit connection according to claim 1, wherein the radical polymerizable compound further comprises a (poly)urethane (meth)acrylate compound.

7. The adhesive film for circuit connection according to claim 1 , further comprising a thermoplastic resin.

8. The adhesive film for circuit connection according to claim 1 , further comprising a coupling agent.

9. The adhesive film for circuit connection according to claim 1 , further comprising a filler.

10. a first circuit member having a first electrode; a second circuit member having a second electrode; a circuit connection portion disposed between the first circuit member and the second circuit member, electrically connecting the first electrode and the second electrode to each other; Equipped with A circuit connection structure, wherein the circuit connection portion comprises a cured product of the adhesive film for circuit connection according to any one of claims 1 to 9.

11. A step of preparing a first circuit member having a first electrode, a second circuit member having a second electrode, and a substrate-attached adhesive film for circuit connection comprising the adhesive film for circuit connection according to any one of claims 1 to 9 on a substrate; transferring the adhesive film for circuit connection from the substrate onto a surface of the first circuit member on which the first electrode is formed; a step of arranging the first circuit member, the adhesive film for circuit connection, and the second circuit member in this order so that the first electrode and the second electrode face each other, and then thermocompressing the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other; A method for manufacturing a circuit connection structure, comprising:

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