JP2007009201A - Electrode-connecting adhesive and connecting structure of fine electrode given by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode-connecting adhesive excellent in heat resistance and connection reliability, and to provide a new structure given by using the same. <P>SOLUTION: This electrode-connecting adhesive comprises a modified phenoxy resin having urethane bonds, a urethane acrylate, and radical reaction initiator. The structure is given by interposing the adhesive between circuit electrodes facing each other and connecting the electrodes by the adhesive. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides an electrode connection adhesive that is placed between an electrode on a first electronic component and an electrode of a second electronic component, and is used for the purpose of electrically connecting and adhering opposed electrodes. The present invention relates to an agent and a connection structure of a fine electrode using the same.

As electronic parts such as semiconductor packages and circuit boards are made smaller and thinner, electrodes used for these components have become denser and more precise. Since connection of these fine electrodes is difficult with conventional solders, rubber connectors and the like, connection members made of an anisotropic conductive adhesive have recently been used frequently. In this method, a connecting member layer made of an adhesive containing a predetermined amount of a conductive material is provided between electrodes facing each other, and an electric connection between upper and lower electrodes is provided simultaneously by applying pressure or heating and pressing means. Insulation is provided between the electrodes, and the electrodes facing each other are bonded and fixed. Examples of the curing means for the adhesive include solidification by cooling at room temperature with a thermoplastic adhesive, heat curing with a thermosetting resin, and ultraviolet and visible light curing with a photocurable resin. Moreover, what utilized the radical polymerization reaction is known as one of the hardening means of the adhesive by a chemical reaction. In this method, radicals are generated by heat or light energy, and the adhesive is polymerized and cured. As a prior art regarding the anisotropic conductive film adhesive having conductivity only in the thickness direction, for example, as disclosed in Japanese Patent Application Laid-Open No. 51-21192 (Patent Document 1), the conductive particles are made non-conductive. A mixture that is held in contact with each other by a base is formed into a sheet shape having a thickness approximately equal to the size of the conductive particles, and has a structure having conductivity only in the thickness direction of the sheet shape through the conductive particles. There is. As an anisotropic conductive adhesive utilizing radical polymerization reaction by ultraviolet irradiation, a method disclosed in JP-A-60-262436 (Patent Document 2) is known. These anisotropic conductive adhesives utilizing radical polymerization reaction are adhesive compositions in which a small amount of a photopolymerization initiator that generates radicals by ultraviolet rays or the like is added by combining several monomers and oligomers having an acryloyl group. However, until now, anisotropic conductive adhesives utilizing radical polymerization reactions have had a problem that high connection reliability with both heat resistance and adhesive strength cannot be obtained. Specifically, in order to improve the heat resistance of the cured adhesive and obtain sufficient connection reliability at high temperatures, the amount of polyfunctional acrylic monomer is increased, and the reactive groups in the adhesive are used. It was necessary to increase the concentration of certain acryloyl groups. However, in this method, since it becomes a cured product having high elasticity and small elongation, the adhesive force is lowered, peeling of the connection interface is likely to proceed, and sufficient connection reliability cannot be obtained.
Japanese Patent Laid-Open No. 51-21192 JP 60-262436 A

  The present invention has been made in view of such a situation, and intends to provide a novel configuration of an electrode connecting adhesive excellent in heat resistance and connection reliability.

  That is, the present invention relates to an electrode connection adhesive containing a modified phenoxy resin having a urethane bond, urethane acrylate and a radical reaction initiator, and a connection structure of a fine electrode using the electrode connection adhesive.

  The adhesive for electrode connection according to claim 1 is suitable for obtaining a connection with high connection reliability in which heat resistance and adhesive force are compatible. The adhesive for electrode connection according to claim 2 has the effect of claim 1 and is excellent in adhesiveness, and can be finely designed with heat resistance and adhesiveness. The adhesive for electrode connection according to claim 3 has the effects of claims 1 to 2 and is excellent in heat resistance, toughness and connection reliability. The adhesive for electrode connection according to claim 4 has the effects of claims 1 to 3 and is excellent in heat resistance. The electrode connecting adhesive according to claim 5 exhibits the effects of claims 1 to 4 and is excellent in both heat resistance and adhesive strength. The adhesives for electrode connection according to claims 6 to 7 have the effects of claims 1 to 5 and can easily produce an acrylic modified phenoxy resin capable of improving the heat resistance and adhesive strength of the adhesive for electrode connection. Is excellent. The adhesive for electrode connection according to claim 8 has the effects of claims 1 to 7 and can further improve the heat resistance and adhesive strength of the adhesive for electrode connection. It is excellent in that an acrylic modified phenoxy resin can be easily produced. The adhesive for electrode connection according to claim 9 is excellent in that it has the effects of claims 1 to 8 and can be connected by a connection step by pressure heating. The adhesive for electrode connection according to claim 10 is excellent in that it has the effects of claims 1 to 8 and can be connected by a connection process including irradiation with ultraviolet light or visible light. The electrode connecting adhesive according to the eleventh aspect has the effects according to the first to tenth aspects, and is excellent in that the connection reliability at a high temperature is particularly high. The adhesive for electrode connection according to claim 12 is excellent in that it has the effects of claims 1 to 11 and a particularly low connection resistance is obtained. The adhesive for electrode connection according to claim 13 is excellent in that the effects of claims 1 to 12 are achieved and particularly high connection reliability is obtained. The adhesive for electrode connection according to claim 14 has the effects of claims 1 to 13 and can provide a connection structure for fine electrodes with high heat resistance and high connection reliability.

  The phenoxy resin is a thermoplastic resin having a bisphenol structure such as bisphenol A or bisphenol F in the repeating unit of the main chain skeleton. By introducing a side chain having an acryloyl group into this phenoxy resin, an acrylic modified phenoxy resin having reaction curability is obtained. Acrylic modified phenoxy resin has improved toughness and high heat resistance due to side chain reaction, as it is a polymer resin. By using it in combination with a bifunctional or polyfunctional acrylic monomer, connection reliability is improved. It becomes possible to improve. Further, by setting the weight average molecular weight of the acrylic modified phenoxy resin to 10,000 or more, the toughness is high, and higher adhesive force and connection reliability can be obtained. Further, as will be described later, the heat resistance and adhesive strength of the adhesive can be arbitrarily adjusted by the number of acryloyl groups in the acrylic modified phenoxy resin, so that by using an acrylic modified phenoxy resin having a weight average molecular weight of 10,000 or more. Therefore, it becomes possible to design a acryloyl radical number that is finer, and to design the heat resistance and adhesive strength of the adhesive.

  As the acrylic monomer or acrylic oligomer having two or more acryloyl groups, various methacrylates and acrylate compounds are used. As the acrylic monomer, for example, one having an acrylic or methacrylic group at both ends of a polyethylene glycol or polypropylene glycol skeleton or one having an acryl or methacrylic group at both ends of a bisphenol skeleton can be used. Moreover, what has three or more acryloyl groups, such as a trimethylol propane trimethacrylate and a tetramethylol methane tetraacrylate, can also be used. As the acrylic oligomer, oligomers such as polyester acrylate, epoxy acrylate, and urethane acrylate can be used. These acrylic monomers or acrylic oligomers are selected so that they form a highly reticulated reaction with the acrylic modified phenoxy resin and do not impair the adhesiveness and toughness of the adhesive. Specifically, an acrylic monomer or acrylic oligomer having two acryloyl groups is used in an amount of 80% or less of the adhesive, and an acrylic monomer or acrylic oligomer having three or more acryloyl groups is used in an amount of 50% or less of the adhesive of the adhesive. Is desirable.

  When the ratio of the acryloyl group to the bisphenol structure in the acrylic modified phenoxy resin is in the range of 0.1 to 1, a remarkable improvement in the heat resistance of the cured product is obtained, and the glass transition temperature of the cured product is increased by the ratio of the acryloyl group. As it gets higher. Therefore, the desired heat resistance can be obtained by adjusting the ratio of the acryloyl group to the bisphenol structure in the acrylic modified phenoxy resin. However, as the proportion of acryloyl groups increases, the toughness of the cured product tends to be impaired, and in order to obtain a high adhesive strength, the proportion of acryloyl groups to the bisphenol structure is generally more suitable in the range of 0.1 to 0.5. It is possible to achieve both good heat resistance and adhesive strength. Here, the ratio of the acryloyl group to the bisphenol structure represents the ratio of the number of bisphenol structures contained in the molecule to the number of acryloyl groups contained in the molecule. That is, when the number of bisphenol structures in the molecule is equal to the number of acryloyl groups in the molecule, the ratio of acryloyl groups to the bisphenol structure is 1, and the number of acryloyl groups in the molecule is relative to the number of bisphenol structures in the molecule. When the number is 1/10, the ratio of the acryloyl group to the bisphenol structure is 0.1.

  Since the main chain skeleton of the phenoxy resin has the same number of hydroxyl groups as the bisphenol structure, it can be reacted with an acrylate having an isocyanate group to produce a urethane bond to produce an acrylic modified phenoxy resin. At this time, the ratio of the acryloyl group to the bisphenol structure can be adjusted to a desired amount by the mixing ratio of the number of hydroxyl groups and the number of isocyanate molecules in the phenoxy resin. This urethane bond formation reaction proceeds rapidly by adding an organotin compound such as dibutyltin laurate as a catalyst in a heated state of about 60 ° C., and an acrylic modified phenoxy resin can be easily obtained. Similarly, by using a phenoxy resin having an amino group bonded to the main chain, it is possible to generate a urea bond and generate an acrylic modified phenoxy resin by reacting with an acrylate having an isocyanate group. The urea bond formation reaction between an amino group and an isocyanate group proceeds more rapidly than the urethane bond formation reaction between a hydroxyl group and an isocyanate group. Therefore, in the case of a phenoxy resin having both amino group and hydroxyl group functional groups, the number of amino groups and the number of isocyanate molecules The ratio of urea-bonded acryloyl groups and urethane-bonded acryloyl groups to the bisphenol structure can be arbitrarily adjusted.

  When 2-methacryloyloxyethyl isocyanate is used as an acrylate having an isocyanate group, an acrylic modified phenoxy resin can be obtained in a high yield due to the high reactivity of the isocyanate, and an adhesive for electrode connection with high heat resistance and adhesive strength can be obtained. It is done. A thermal radical initiator that generates radicals by the heat of an organic peroxide such as benzoyl peroxide or an azo compound such as azobisisobutylnitrile is mixed with the adhesive for electrode connection made of a resin having an acrylate group. In this way, an electrode connecting adhesive that is cured by heating can be obtained, and a highly reliable connection can be obtained at a low temperature in a short heating and pressurizing connection process. In addition, when a radical initiator such as benzophenone or thioxanthone that generates radicals by ultraviolet light or visible light is mixed instead of a thermal radical reaction initiator, by irradiating the adhesive with ultraviolet light or visible light at the time of connection, A reliable connection can be obtained at a low temperature and with a short connection time. As described above, the glass transition temperature of the cured product bonded in this connection step varies depending on the ratio of acryloyl groups to the bisphenol structure of the acrylic modified phenoxy resin. When the glass transition temperature is 100 ° C. or higher, 85 ° C. and 85% RH. In an accelerated test such as a high-temperature and high-humidity test and a thermal shock test of -40 ° C to 100 ° C, there is no peeling of the connection portion, and particularly good connection reliability with low resistance is obtained. In addition, this electrode connecting adhesive is often used after being formed into a film shape excellent in handleability and pot life. As a film forming material for this film electrode connecting adhesive, acrylic modified phenoxy resin is used. Can be used. The thickness of the film-like electrode connecting adhesive is not particularly limited, but the adhesive force and moisture resistance are improved by filling the unevenness of the electrode part to be connected with the adhesive. A thickness greater than or equal to the unevenness is suitable. Moreover, since it will become difficult to handle if it becomes thin, and manufacturing will become difficult by generation | occurrence | production of wrinkles etc., 0.005 mm-1 mm are suitable.

  Since the acrylic modified phenoxy resin has a lower melt viscosity than the original unmodified phenoxy resin, the resin viscosity during connection of the electrode connecting adhesive is also reduced, and the adhesive between the electrodes facing each other is easily eliminated. Therefore, connection with low resistance becomes possible. In particular, a low resistance value is obtained when the viscosity of the adhesive at the time of connection is 5 Pa · s or less, and a stable low resistance value is obtained at 2 Pa · s or less. In addition, by adding conductive particles to the electrode connecting adhesive, a connection with a low connection resistance and a high reliability in which an increase in resistance in a high temperature and high humidity test or the like is suppressed can be obtained. The conductive particles can be used alone or in combination with metal plating resin particles in which a plating layer of Ni or Au is provided on the surface of metal particles such as Ni or resin particles. As the material of these conductive particles, an optimum material is selected and used according to characteristics such as hardness and deformability of the electrode to be connected. The particle size is selected according to the fineness of the circuit to be connected, but it is desirable that the particle size of each particle is as uniform as possible. Further, the electrode connecting adhesive of the present invention can be applied not only to the electrode connecting material described above but also to an interlayer connecting material of a multilayer circuit member.

  Hereinafter, details will be described based on examples of the present invention, but the present invention is not limited thereto. The materials and evaluation methods used in the examples and comparative examples are shown below. As the acrylic modified phenoxy resin, those obtained by reacting various phenoxy resins with 2-methacryloyloxyethyl isocyanate (trade name Karenz MOI, manufactured by Showa Denko KK) were used. Phenoxy resin (trade name PKHA weight average molecular weight of about 20,000, PKHC weight average molecular weight of about 25,000, PKHJ weight average molecular weight of about 35,000, manufactured by Union Carbide Corporation) and 2-methacryloyloxyethyl isocyanate (Showa Denko Co., Ltd.) An acrylic modified phenoxy resin in which the side chain having an acryloyl group is bonded by a urethane bond (hereinafter referred to as an urethane modified acrylic modified phenoxy resin) is produced by reacting with a company, product name Karenz MOI) Phenoxy resin (trade name YP-60, weight average molecular weight of about 20,000, manufactured by Toto Kasei Co., Ltd.) and 2-methacryloyloxyethyl isocyanate (trade name, Karenz MOI, manufactured by Showa Denko KK) are reacted to form an acryloyl group. The side chain it has is bonded with a urea bond And is an acrylic-modified phenoxy resin (hereinafter, referred to as a urea bond-containing acrylic-modified phenoxy resin) was prepared. The acryloyl group content of the produced acrylic modified phenoxy resin was represented by the number of acryloyl groups relative to the bisphenol structure. The acryloyl group content was adjusted by the mixing ratio of the reacted phenoxy resin and 2-methacryloyloxyethyl isocyanate, and it was confirmed by Raman spectroscopy that the acryloyl group was reacted at this mixing ratio. The acrylic oligomer is urethane acrylate (made by Shin-Nakamura Chemical Co., Ltd., trade name UA-122P), and the acrylic monomer is tetramethylol methane triacrylate (made by Shin-Nakamura Chemical Co., Ltd., trade name A-TMM-3L). ) Was used. Further, γ-methacryloxypropyltrimethoxysilane (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name SZ6030) was added as a silane coupling agent for improving the adhesive strength.

The conductive particles used were polystyrene spherical particles having an average particle diameter of 5 μm provided with a 0.1 μm Ni layer and an Au layer on the surface. 5% by weight of benzoyl peroxide (reagent) is added as a reaction initiator to the thermosetting electrode connecting adhesive, and benzophenone (reagent) is added as a reaction initiator to the ultraviolet curable electrode connecting adhesive. 4% by weight, 4,4-bisdiethylaminobenzophenone (made by Hodogaya Chemical Co., Ltd., trade name EAB) was added as a photoreaction accelerator. The viscosity at the connection temperature was measured with an adhesive without adding a reaction initiator. The liquid electrode connecting adhesive was applied and connected on the electrode using a syringe-like dispenser. The film-like adhesive for electrode connection was formed by coating an adhesive diluted with a solvent of methyl ethyl ketone or ethyl acetate on a Teflon film with an applicator and then drying to form a film having a thickness of about 20 μm. When connecting, a film-like adhesive for electrode connection was transferred from the Teflon film to the electrode surface, and the Teflon film was removed for use. The connection reliability was evaluated by bonding an FPC having 100 copper electrodes arranged in parallel on a polyimide film with a line width of 50 μm, a pitch of 100 μm and a thickness of 18 μm, and a glass substrate having an ITO electrode with a surface resistance of 20Ω / □. This was performed using a sample connected by an agent. When a thermosetting electrode connecting adhesive was used, the connection was made by pressure heating at 150 ° C. for 20 seconds at a pressure of 20 kg / cm ² . When an ultraviolet curable adhesive for electrode connection was used, the adhesive was irradiated with about ² J / cm ² of ultraviolet light at a pressure of 20 kg / cm ² and heated at 130 ° C. for 20 seconds. Ultraviolet rays were irradiated by using a high-pressure mercury lamp as a light source and introducing ultraviolet rays into the adhesive at the connection portion by an optical fiber. The cured adhesive formed into a film was subjected to dynamic viscoelasticity measurement, the glass transition temperature was measured, and used as an index of heat resistance. For the preparation conditions of the cured adhesive, a heat-treated adhesive at 150 ° C. for 20 seconds was used, and in the case of an ultraviolet curable adhesive, a cured product irradiated with ultraviolet rays at 130 ° C. for 2 J was used. The connection resistance was measured for each line with a measurement current of 1 mA, and the average value was taken as the connection resistance. Reliability evaluation was performed in 1000 cycles of a thermal cycle test in which samples were alternately placed in each test bath at −40 ° C. and 100 ° C. For the evaluation of adhesive strength, the adhesion of FPC to ITO glass was measured by a 90-degree peel test.

Example 1
A urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 20,000 with a ratio of acryloyl group to bisphenol structure of about 20% (weight, hereinafter the same), urethane acrylate oligomer 40%, tetramethylol methane triacrylate 25%, silane A 10% coupling agent and 5% benzoyl peroxide were uniformly mixed to prepare an adhesive for circuit connection.

(Example 2)
20% of urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 20,000 with a ratio of acryloyl group to bisphenol structure of 1, 20,000, urethane acrylate oligomer 40%, tetramethylol methane triacrylate 25%, silane coupling agent 10%, A 4% photoreaction initiator and 1% photoreaction accelerator were uniformly mixed to prepare an adhesive for circuit connection.

(Example 3)
55% of urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 25,000 with a ratio of acryloyl group to bisphenol structure of about 25,000, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, silane coupling agent 10 % And benzoyl peroxide 5% were uniformly mixed to prepare an adhesive for film-like circuit connection.

Example 4
55% of urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 25,000 with a ratio of acryloyl group to bisphenol structure of about 25,000, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, silane coupling agent 10 %, A photoreaction initiator 4%, and a photoreaction accelerator 1% were uniformly mixed to prepare an adhesive for film-like circuit connection.

(Example 5)
55% of urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 35,000 with a ratio of acryloyl group to bisphenol structure of about 35,000, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, silane coupling agent 10 %, A photoreaction initiator 4%, and a photoreaction accelerator 1% were uniformly mixed to prepare an adhesive for film-like circuit connection.

(Example 6)
55% of urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 25,000 with a ratio of acryloyl group to bisphenol structure of about 25,000, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, silane coupling agent 10 %, A photoreaction initiator 4%, and a photoreaction accelerator 1% were uniformly mixed to prepare an adhesive for film-like circuit connection.

(Example 7)
55% of urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 25,000 with a ratio of acryloyl group to bisphenol structure of about 25,000, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, silane coupling agent 10 %, A photoreaction initiator 4%, and a photoreaction accelerator 1% were uniformly mixed to prepare an adhesive for film-like circuit connection.

(Example 8)
55% of urethane bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 25,000 with a ratio of acryloyl group to bisphenol structure of about 25,000, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, silane coupling agent 10 %, A photoreaction initiator 4%, and a photoreaction accelerator 1% were uniformly mixed to prepare an adhesive for film-like circuit connection.

Example 9
55% acrylic modified phenoxy resin containing urea bond and urethane bond having a weight average molecular weight of about 20,000 having a ratio of acryloyl group to bisphenol structure of 0.7, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, A film-like circuit connection adhesive was prepared by uniformly mixing 10% of a silane coupling agent, 4% of a photoreaction initiator, and 1% of a photoreaction accelerator.

(Examples 10 to 18)
Examples 10 to 18 were obtained by adding 5% by volume of conductive particles to Example 1 to Example 9, respectively.

(Reference Example 1)
55% of urea bond-containing acrylic modified phenoxy resin having a weight average molecular weight of about 20,000 with a ratio of acryloyl group to bisphenol structure of 0.30, urethane acrylate oligomer 20%, tetramethylol methane triacrylate 10%, silane coupling agent 10 %, A photoreaction initiator 4%, and a photoreaction accelerator 1% were uniformly mixed to prepare an adhesive for film-like circuit connection.

(Reference Example 2)
Reference Example 2 was obtained by adding 5% by volume of conductive particles to Reference Example 1.

(Comparative Example 1)
The acrylic modified phenoxy resin of Example 1 was a phenoxy resin not modified with acrylic.

(Comparative Example 2)
The acrylic modified phenoxy resin of Example 2 was a phenoxy resin that was not acrylic modified.

(Comparative Example 3)
The acrylic modified phenoxy resin of Example 3 was a phenoxy resin not subjected to acrylic modification.

(Comparative Example 4)
The acrylic modified phenoxy resin of Example 4 was a phenoxy resin not subjected to acrylic modification.

(Comparative Example 5)
The acrylic modified phenoxy resin of Example 10 was a phenoxy resin not subjected to acrylic modification.

(Comparative Example 6)
The acrylic modified phenoxy resin of Example 11 was a phenoxy resin not subjected to acrylic modification.

(Comparative Example 7)
The acrylic modified phenoxy resin of Example 12 was a phenoxy resin not subjected to acrylic modification.

(Comparative Example 8)
The acrylic modified phenoxy resin of Example 13 was a phenoxy resin not subjected to acrylic modification.

(Comparative Example 9)
20% epoxy acrylate oligomer (trade name ES-4004, manufactured by Kyoeisha Chemical Co., Ltd.) having a weight average molecular weight of about 2,000 having a bisphenol A structure, urethane acrylate oligomer 40%, tetramethylol methane triacrylate 25%, silane coupling agent 10 %, Photoreaction initiator 4%, and photoreaction accelerator 1% were uniformly mixed to produce an adhesive for circuit connection.

(Comparative Example 10)
20% epoxy acrylate oligomer (trade name ES-4004, manufactured by Kyoeisha Chemical Co., Ltd.) having a weight average molecular weight of about 2,000 having a bisphenol A structure, 35% phenoxy resin having a weight average molecular weight of about 25,000, 20% urethane acrylate oligomer, Tetramethylolmethane triacrylate 10%, silane coupling agent 10%, photoreaction initiator 4%, and photoreaction accelerator 1% were uniformly mixed to prepare an adhesive for film-like circuit connection.

Table 1 shows the viscosity, glass transition temperature, adhesive strength, initial connection resistance, and connection resistance after the reliability test of each Example and Comparative Example. All of the adhesives for electrode connection according to the present invention are excellent in heat resistance and connection reliability.

Sectional drawing of the electrode connection structure using the adhesive agent for electrode connection containing the electrically-conductive particle concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Adhesive for electrode connection, 2 ... Adhesive, 3 ... Conductive particle, 4 ... 1st electrode, 5 ... 2nd electrode

Claims (14)

  An electrode-connecting adhesive that is placed between the electrode on the first electronic component and the electrode of the second electronic component and electrically connects and bonds the opposed electrodes and has a urethane bond An adhesive for electrode connection containing a modified phenoxy resin, urethane acrylate and a radical reaction initiator.   The adhesive for electrode connection according to claim 1, wherein the modified phenoxy resin has a weight average molecular weight of 10,000 or more.   The adhesive for electrode connection according to claim 1 or 2, wherein the modified phenoxy resin further has an acryloyl group.   The adhesive for electrode connection according to claim 3, wherein the modified phenoxy resin is a modified phenoxy resin in which a ratio of acryloyl groups to a bisphenol structure of the phenoxy resin is 0.1 to 1. 5.   The adhesive for electrode connection according to claim 3 or 4, wherein the modified phenoxy resin is a modified phenoxy resin in which a ratio of an acryloyl group to a bisphenol structure of the phenoxy resin is 0.1 to 0.5.   The adhesive for electrode connection according to any one of claims 3 to 5, wherein the modified phenoxy resin is a modified phenoxy resin in which a main chain of the phenoxy resin and a side chain having an acryloyl group are bonded by a urethane bond.   The modified phenoxy resin includes a modified phenoxy containing both a side chain having an acryloyl group bonded to the main chain of the phenoxy resin by a urethane bond and a side chain having an acryloyl group bonded to the main chain by a urea bond. It is resin, The adhesive agent for electrode connections in any one of Claims 3-6.   The adhesive for electrode connection according to claim 3, wherein the modified phenoxy resin is a modified phenoxy resin that is a reaction product of a hydroxyl group of the main chain of the phenoxy resin and an isocyanate group of 2-methacryloyloxyethyl isocyanate.   The adhesive for electrode connection according to any one of claims 1 to 8, wherein the radical reaction initiator comprises a thermal radical reaction initiator such as an organic peroxide.   The adhesive for electrode connection according to any one of claims 1 to 8, wherein the radical reaction initiator is a radical reaction initiator that generates radicals by ultraviolet light or visible light.   The adhesive for electrode connection according to any one of claims 1 to 10, wherein the glass transition temperature of the cured product is 100 ° C or higher.   The adhesive for electrode connection according to claim 1, wherein the viscosity at the time of connection is 5 Pa · s or less.   The adhesive agent for electrode connection in any one of Claims 1-12 formed by adding electroconductive particle.   The connection structure of the fine electrode using the adhesive agent for electrode connection in any one of Claims 1-13.

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