JP7294145B2 - Adhesive composition, connection structure and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive composition, a connection structure and a method for producing the same.

2. Description of the Related Art In recent years, electronic components have become smaller, thinner, and have higher performance. It is difficult to connect electronic components having fine circuit electrodes and circuit members with conventional solder and rubber connectors. Therefore, connection methods using an anisotropically conductive adhesive composition and its film (adhesive film) with excellent resolution, as disclosed in Patent Documents 1 to 6, are frequently used. For example, an anisotropic conductive adhesive containing conductive particles when connecting the glass of a liquid crystal display and a circuit member such as TAB (Tape Automated Bonding) or FPC (Flexible Print Circuit) By sandwiching the film between the facing electrodes and applying heat and pressure, the electrodes on both substrates are electrically connected while maintaining the insulation between adjacent electrodes on the same substrate, forming fine circuit electrodes. and the circuit member are crimped and fixed.

In addition, there is a demand for lighter, thinner, and more sensitive modules, and in display modules such as liquid crystal display devices and electronic paper, or substrates for sensors such as touch panels, for the purpose of reducing wiring resistance, It is necessary to reduce the wiring resistance while narrowing the width of the wiring by using copper, gold, aluminum and their alloys with low surface resistance in place of the conventional silver paste. Also in the anisotropically conductive adhesive film, studies are being made to optimize the raw materials and the like contained in the adhesive film for the purpose of reducing the connection resistance.

JP-A-08-148213 JP-A-08-124613 JP-A-11-50032 JP 2011-91044 A JP 2011-100605 A JP 2013-55058 A

Among the above-mentioned metals with low surface resistance, investigations are being made to use readily available copper, copper alloys, copper oxides, and the like for electrodes. However, when a conventional adhesive film is applied to such an electrode, for example, the connection resistance may increase over time, and there is room for further improvement in terms of connection reliability.

Accordingly, an object of the present invention is to provide an adhesive composition capable of suppressing an increase in connection resistance and improving connection reliability. Another object of the present invention is to provide a connection structure excellent in connection reliability and a manufacturing method thereof.

One aspect of the present invention is an adhesive composition containing conductive particles and a compound having a nitrogen-containing aromatic heterocycle.

The nitrogen-containing aromatic heterocyclic ring is preferably at least one selected from the group consisting of pyrazole ring, imidazole ring, triazole ring, tetrazole ring, thiazole ring, thiadiazole ring, oxazole ring and pyrimidine ring. Thereby, the connection reliability can be further improved.

The adhesive composition is preferably used to connect circuit members.

Another aspect of the present invention provides a first circuit member having a first substrate and a first electrode provided on the first substrate, a second substrate and a circuit member provided on the second substrate. and a circuit disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other. A connection member, wherein the circuit connection member is a connection structure that is a cured product of the adhesive composition.

The first and second electrodes are preferably copper, copper alloys, or copper oxides.

Another aspect of the present invention provides a first circuit member having a first substrate and a first electrode provided on the first substrate, a second substrate and a circuit member provided on the second substrate. The adhesive composition is placed between the second circuit member having the second electrode and the first circuit member and the second circuit member are bonded via the adhesive composition. A method of manufacturing a connection structure, comprising the step of crimping to electrically connect a first circuit member and a second circuit member.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can suppress a raise of connection resistance and can improve connection reliability can be provided. Moreover, the present invention can provide a connection structure excellent in connection reliability and a manufacturing method thereof.

1 is a schematic cross-sectional view showing an adhesive film according to one embodiment; FIG. It is a schematic cross section which shows the manufacturing method of the connection structure which concerns on one Embodiment. 1 is a schematic cross-sectional view showing a copper electrode film-attached body used in Examples. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

An adhesive composition according to one embodiment includes an adhesive component and conductive particles dispersed in the adhesive component. The adhesive component is defined as the non-volatile matter other than the conductive particles in the adhesive composition.

The conductive particles have, for example, polymer particles (plastic particles) such as polystyrene, and a metal layer covering the polymer particles. Preferably, substantially the entire surface of the polymer particle is coated with a metal layer, but a part of the surface of the polymer particle is not coated with the metal layer as long as the function as a circuit connecting material is maintained. may be exposed to The polymer particles may be, for example, particles containing a polymer containing at least one monomer selected from styrene and divinylbenzene as a monomer unit.

The average particle size of the polymer particles may preferably be 1 μm or more, 40 μm or less, or 1 to 40 μm. From the viewpoint of high-density mounting, the average particle size of the polymer particles may more preferably be 30 μm or less, and may be 1 to 30 μm. From the viewpoint of maintaining a more stable connection state even when the surface unevenness of the electrode is uneven, the average particle size of the polymer particles is more preferably 2 μm or more and 20 μm or less, It may be 2-20 μm. The average particle size of the polymer particles can be obtained by observing with a scanning electron microscope (SEM), measuring the particle sizes of 300 polymer particles, and obtaining the average value.

The metal layer may be made of various metals such as Ni, Ni/Au, Ni/Pd, Cu, NiB, Ag, and Ru. The metal layer may be a thin film produced by plating, vapor deposition, sputtering, or the like.

From the viewpoint of improving insulation, the conductive particles may further have an insulating layer provided outside the metal layer and covering the metal layer. The insulating layer may be a layer made of an insulating material such as silica or acrylic.

The conductive particles preferably have a surface forming a plurality of protrusions. Conductive particles having protrusions can be obtained, for example, by forming a metal layer on the surface of polymer particles by metal plating.

The content of the conductive particles is determined according to the fineness of the electrodes to be connected. For example, the content of the conductive particles may be 1 part by volume or more, 50 parts by volume or less, or 1 to 50 parts by volume with respect to 100 parts by volume of the adhesive component. From the viewpoint of insulation and manufacturing cost, the content of the conductive particles is more preferably 30 parts by volume or less, and may be 1 to 30 parts by volume with respect to 100 parts by volume of the adhesive component.

In one embodiment, the adhesive component contains a radically polymerizable substance that has insulating properties and is cured by heat or light, a free radical generator, and a compound having a nitrogen-containing aromatic heterocycle.

A radically polymerizable substance is a substance having a functional group that undergoes radical polymerization, and examples thereof include acrylate compounds, methacrylate compounds, and maleimide compounds. The content of the radically polymerizable substance may be, for example, 50% by mass or more, 80% by mass or less, or 50 to 80% by mass, based on the total amount of the adhesive component.

Examples of acrylate compounds and methacrylate compounds include urethane acrylate, urethane methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, and dimethyloltricyclodecane diacrylate. , trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4 -(acryloxypolyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, bis(acryloxyethyl)isocyanurate, ε-caprolactone-modified tris(acryloxyethyl)isocyanurate, and tris(acryloxyethyl) ) isocyanurate. Radically polymerizable substances are used singly or in combination of two or more. From the viewpoint of adhesiveness, the radical polymerizable substance is preferably urethane acrylate or urethane methacrylate.

As the radically polymerizable substance, from the viewpoint of improving heat resistance, a combination of urethane acrylate or urethane methacrylate and a radically polymerizable substance that alone exhibits a Tg of 100° C. or higher when crosslinked with an organic peroxide is used. is particularly preferred. Such a radically polymerizable substance may be a compound having a dicyclopentenyl group and/or a tricyclodecanyl group, preferably a compound having a tricyclodecanyl group.

The viscosity of the radically polymerizable substance at 25° C. may be 100,000 mPa·s or more, may be 1,000,000 mPa·s or less, may be 100,000 to 1,000,000 mPa·s, and preferably may be 500,000 mPa·s or less. It may be 100,000 to 500,000 mPa·s. The viscosity of the radically polymerizable substance at 25° C. can be measured using a commercially available E-type viscometer.

The free radical generator is a compound that is decomposed by heat or light to generate free radicals, such as a peroxide compound or an azo compound. The free radical generator is appropriately selected according to the desired connection temperature, connection time, pot life, and the like. The free radical generator may be, for example, one or more selected from benzoyl peroxide, diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide and hydroperoxide. From the viewpoint of high reactivity and pot life, the free radical generator is preferably an organic peroxide compound having a half-life of 10 hours at a temperature of 40°C or higher and a half-life of 1 minute at a temperature of 180°C or lower. be. The content of the free radical generator may be, for example, 0.05% by mass or more, 15% by mass or less, or 0.05 to 15% by mass, based on the total amount of the adhesive component. . When the adhesive component contains a free radical generator, the free radical generator may be used in combination with decomposition accelerators, inhibitors, and the like.

The adhesive component of this embodiment may further contain a polymerization inhibitor. The polymerization inhibitor may be a hydroquinone compound, a methyl ether hydroquinone compound, or the like. The content of the polymerization inhibitor may be 0.05% by mass or more, 5% by mass or less, or 0.05 to 5% by mass based on the total amount of the adhesive component.

A compound having a nitrogen-containing aromatic heterocyclic ring (hereinafter also simply referred to as a "heterocyclic compound") is a compound having an aromatic heterocyclic ring containing one or more nitrogen atoms in the ring. Nitrogen-containing aromatic heterocyclic ring (hereinafter also simply referred to as "heterocyclic ring") is composed of at least two kinds of atoms, a carbon atom and a nitrogen atom, and in addition to the carbon atom and the nitrogen atom, a sulfur atom and an oxygen atom It may be composed of three or more kinds of atoms including other atoms such as . The heterocyclic ring contains, for example, 1 to 4 nitrogen atoms, preferably 2 to 4 nitrogen atoms. When the heterocyclic ring contains one nitrogen atom, the heterocyclic ring preferably further contains the above-described other atoms in addition to the carbon and nitrogen atoms.

A heterocycle is preferably a compound having a 5- or 6-membered ring, more preferably a compound having a 5-membered ring (azole). Five-membered rings include, for example, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, thiazole ring, thiadiazole ring, oxazole ring and the like. The 6-membered ring includes, for example, a pyrimidine ring.

The heterocyclic ring preferably consists of a pyrazole ring, an imidazole ring, a triazole ring, a tetrazole ring, a thiazole ring, a thiadiazole ring, an oxazole ring and a pyrimidine ring, from the viewpoint of suppressing an increase in connection resistance and further improving connection reliability. At least one selected from the group, more preferably at least one selected from the group consisting of a pyrazole ring, an imidazole ring, a triazole ring, a tetrazole ring, a thiazole ring, a thiadiazole ring and an oxazole ring, more preferably It is at least one selected from the group consisting of a triazole ring, a tetrazole ring and a thiadiazole ring.

A heterocyclic ring may be unsubstituted or may have a substituent (a hydrogen atom bonded to an atom constituting the heterocyclic ring is substituted). When the heterocyclic ring has a substituent, the substituent may be a hydrocarbon group or an organic group containing a sulfur atom, an oxygen atom, or the like. The hydrocarbon groups may be alkyl groups and the like. An organic group containing a nitrogen atom may be an amino group or the like. The organic group containing a sulfur atom may be a mercapto group and the like.

The heterocyclic compound may have a monocyclic nitrogen-containing aromatic heterocyclic ring, for example, an aromatic ring composed only of hydrocarbon (e.g., substituted or unsubstituted benzene ring) It may have a polycyclic ring condensed with a nitrogen aromatic heterocycle. Such polycycles can be, for example, benzimidazole rings, benzotriazole rings, benzothiazole rings, benzoxazole rings, and the like.

Heterocyclic compounds are specifically 5-methyltetrazole, 5-amino-1H-tetrazole, 3-mercapto-1,2,4-triazole, benzotriazole, 2-aminopyrimidine, 5,6-dimethylbenzimidazole , 2-amino-5-mercapto-1,3,4-thiadiazole, 2-mercaptopyrimidine, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, and the like.

The content of the heterocyclic compound is preferably 0.01 part by volume or more, more preferably 0.01 part by volume or more per 100 parts by volume of the adhesive component, from the viewpoint of suppressing an increase in connection resistance and further improving connection reliability 0.1 volume part or more, more preferably 0.2 volume part or more, preferably 5 volume parts or less, more preferably 2 volume parts or less, still more preferably 1 volume part or less be.

In another embodiment, the adhesive component contains a thermosetting resin and the compound having the nitrogen-containing aromatic heterocycle described above.

Thermosetting resins include, for example, epoxy resins, cyanate ester resins, maleimide resins, allyl nadimide resins, phenol resins, urea resins, alkyd resins, acrylic resins, unsaturated polyester resins, diallyl phthalate resins, silicone resins, and resorcinol formaldehyde resins. , xylene resins, furan resins, polyurethane resins, ketone resins, triallyl cyanurate resins, polyisocyanate resins, resins containing tris(2-hydroxyethyl) isocyanurate, resins containing triallyl trimellitate, cyclopentadiene and thermosetting resins obtained by trimerization of aromatic dicyanamide. A thermosetting resin is used individually by 1 type or in combination of 2 or more types. The content of the thermosetting resin may be, for example, 20% by mass or more, 50% by mass or less, or 20 to 50% by mass based on the total amount of the adhesive component.

When the adhesive component contains a thermosetting resin, the adhesive component may further contain a curing agent. The curing agent may be, for example, a catalytic curing agent. Catalytic curing agents may be hydrazides, boron trifluoride-amine complexes, sulfonium salts, amine imides, diaminomaleonitrile, polyamine salts, dicyandiamides, etc., or modifications thereof. The curing agent may be a polyaddition type curing agent such as polyamines, polymercaptans, polyphenols, acid anhydrides and the like. A polyaddition-type curing agent and a catalyst-type curing agent may be used in combination as the curing agent. Curing agents may be used alone or in combination of two or more. The content of the curing agent may be 0.5 mass % or more, 15 mass % or less, or 0.5 to 15 mass % based on the total amount of the adhesive component.

The curing agent is microencapsulated by coating the above-mentioned curing agent with a polymer compound such as polyurethane or polyester, or a thin metal film such as Ni or Cu, or an inorganic compound such as calcium silicate. good too. Such curing agents are preferred because they can extend the pot life.

In another embodiment, the adhesive component contains the above-described radically polymerizable substance, free radical generator, thermosetting resin, and compound having a nitrogen-containing aromatic heterocycle.

In the present embodiment, the total content of the radically polymerizable substance and the content of the thermosetting resin may be, for example, 50% by mass or more and 80% by mass or less based on the total amount of the adhesive component. may be from 50 to 80% by mass.

In each of the above-described embodiments, the adhesive component further contains a filler such as silicone particles, a softening agent, an accelerator, an antioxidant, a coloring agent, a flame retardant, a thixotropic agent, a coupling agent, and the like. can also

The adhesive composition may be in the form of a paste, or preferably in the form of a film from the viewpoint of handling properties. FIG. 1 is a schematic cross-sectional view showing a film-like adhesive composition (adhesive film) according to one embodiment. As shown in FIG. 1, the adhesive film 1 is, in one embodiment, composed of a layer of an adhesive component 2 and conductive particles 3 dispersed in the adhesive component 2 . The adhesive component 2 and conductive particles 3 may, in one embodiment, be the adhesive component and conductive particles described above. The thickness of the adhesive film 1 may be, for example, 10 μm or more, 50 μm or less, or 10 to 50 μm.

When the adhesive composition is formed into a film, the adhesive component may contain an insulating resin other than the thermosetting resin described above in order to improve the film formability. As the insulating resin, polystyrene, polyethylene, polyvinyl butyral, polyvinyl formal, polyimide, polyamide, polyvinyl chloride, polyphenylene oxide, urea resin, phenoxy resin, polyimide resin, polyester urethane resin, etc. may be used. From the viewpoint of increasing, it may be a high-molecular-weight phenoxy resin having a weight-average molecular weight of 10,000 or more as determined by high-performance liquid chromatography (HPLC). The adhesive component may contain these resins modified with radically polymerizable functional groups, or contain a mixture of these resins and styrene resins or acrylic resins for adjusting melt viscosity. You may In other embodiments, the adhesive component may contain rubber to enhance film forming properties.

The adhesive film can also be of multilayer construction. The adhesive film has, for example, a two-layer structure composed of a layer containing conductive particles and a layer not containing conductive particles, or a layer containing conductive particles and conductive particles provided on both sides thereof. It may be a three-layer structure composed of a layer that does not contain The adhesive film may be provided with a plurality of layers containing conductive particles. These multi-layered adhesive films are suitable for narrow-pitch connection because the conductive particles can be efficiently arranged on the electrodes. Considering the adhesiveness with the circuit members, the adhesive film may further have an adhesive layer that exhibits high adhesiveness to each circuit member to be connected.

The adhesive composition (adhesive film) described above is suitably used as a material for connecting circuit members (circuit connecting material), and is an anisotropically conductive adhesive composition for connecting circuit members. It is particularly preferably used as (anisotropic conductive adhesive film).

Next, a method for manufacturing a connection structure using the adhesive film 1 will be described. FIG. 2 is a schematic cross-sectional view showing a method for manufacturing a connection structure according to one embodiment. First, as shown in FIG. 2A, a first circuit member 6 having a first substrate 4 and a first electrode 5 provided on the first substrate 4, A second circuit member 9 having a second electrode 8 provided on a second substrate 7 is prepared.

Next, the first circuit member 6 and the second circuit member 9 are arranged so that the first electrode 5 and the second electrode 8 face each other, and the first circuit member 6 and the second circuit are arranged. An adhesive film 1 is arranged between the member 9 and the adhesive film 1 .

Then, the adhesive film 1 is cured while applying pressure in the directions of arrows A and B. The pressure during pressurization may be, for example, 1 to 10 MPa per total connection area. The method for curing the adhesive film 1 may be a method using heating, or a method using light irradiation in combination with heating. Heating may be performed, for example, at 100-170°C. Pressurization and heating (light irradiation if necessary) may be performed, for example, for 1 to 160 seconds. As a result, the first circuit member 6 and the second circuit member 9 are pressure-bonded via the cured adhesive composition forming the adhesive film 1 .

In this embodiment, the adhesive film 1 is arranged between the first circuit member 6 and the second circuit member 9, but as another embodiment, instead of the adhesive film, a paste adhesive composition The material may be applied onto the first circuit member 6 or the second circuit member 9 or both.

The connection structure 11 according to one embodiment obtained in this manner includes the first substrate 4 and the first electrode 5 provided on the first substrate 4, as shown in FIG. 2(b). a first circuit member 6 having; a second circuit member 9 having a second substrate 7 and a second electrode 8 provided on the second substrate 7; and a circuit connection member 10 arranged between the circuit member 9 and electrically connecting the first electrode 5 and the second electrode 8 to each other. The circuit connecting member 10 is composed of a cured product of an adhesive composition, and is composed of a cured product 12 of the adhesive component 2 and conductive particles 3 dispersed in the cured product 12 . In the connection structure 11, the first electrode 5 and the second electrode 8 are electrically connected to each other by interposing the conductive particles 3 between the first electrode 5 and the second electrode 8. ing.

The first substrate 4 and the second substrate 7 may be the same or different. It may be a composite substrate having an insulating film.

The flexible substrate is, for example, an organic substrate made of an organic material containing at least one thermoplastic resin selected from polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC) and polyethylene naphthalate (PEN). you can

The flexible substrate may further have a modified film such as a hard coat and/or a protective film formed on the surface of the organic substrate to improve optical and mechanical properties. In order to facilitate handling and transportation of the flexible substrate, a reinforcing material selected from glass material, SUS, etc. may be attached to the organic substrate.

The thickness of the flexible substrate is preferably 10 μm or more, 200 μm or less, or 10 to 200 μm, from the viewpoint of ensuring the strength and bendability of the substrate alone as a film, More preferably, it may be 125 μm or less, and may be 10 to 125 μm.

When conventional circuit-connecting materials are used, the electrodes on the flexible substrate tend to be broken or cracked due to heat and pressure for crimping the circuit members together. Further, in connection with electrodes that are difficult to form a sufficient electrical connection, it is necessary to crimp the circuit members under conditions of lower temperature or lower stress in order to suppress breakage of the electrodes. The adhesive film 1 of the present embodiment can also have advantageous effects in these respects as compared with conventional materials.

The glass substrate may be made of soda glass, quartz glass, or the like. From the viewpoint of preventing breakage due to external stress, substrates made of these materials may be subjected to chemical strengthening treatment. The composite substrate may have a glass substrate and an insulating film formed on the surface of the glass substrate and made of polyimide or an additive organic or inorganic material for decoration. In the composite substrate, electrodes may be formed on the insulating film.

As a combination of the first substrate 4 and the second substrate 7, more specifically, the first substrate 4 is an IC chip or a flexible substrate containing a thermoplastic resin, and the second substrate 7 is a thermoplastic resin. It may be a flexible substrate including Alternatively, the first substrate 4 may be an IC chip or flexible substrate, and the second substrate 7 may be a glass substrate or composite substrate. In other words, when the second substrate 7 is a flexible substrate, the first substrate 4 may be an IC chip or a flexible substrate. When the first substrate 4 is an IC chip and the second substrate 7 is a flexible substrate, the above adhesive film 1 is used for COP (Chip on Plastic substrate) connection. When the first substrate 4 and the second substrate 7 are flexible substrates, the adhesive film 1 described above is used for FOP (Film on Plastic substrate) connection.

When the second substrate 7 is a flexible substrate, the first circuit member 6 includes electronic components such as active elements such as semiconductor chips, transistors, diodes and thyristors; passive elements such as capacitors, resistors and coils; A printed circuit board or a glass substrate on which a circuit is formed with ITO or the like may be used. When the first substrate 4 is a semiconductor chip or a glass substrate, the bumps formed by plating or the tips of the gold wires are melted with a torch or the like to form gold balls, which are crimped onto the electrode pads. A projecting electrode such as a wire bump obtained by cutting a wire can be provided and used as the first circuit member 6 .

Electrode materials for forming the first electrode 5 and the second electrode 8 include metals such as Ag, Ni, Al, Au, Cu, Ti and Mo, and transparent materials such as ITO, IZO, silver nanowires and carbon nanotubes. An electric conductor is mentioned. The first electrode 5 and the second electrode 8 may be made of the same material or different materials, but are preferably made of the same material. The first electrode 5 and the second electrode 8 are preferably made of copper, copper alloy, or copper oxide from the viewpoint of reduction of connection resistance and availability. A surface layer such as an oxide or nitride film, an alloy film, or an organic film may be further provided on the first electrode 5 and the second electrode 8 from the viewpoint of disconnection prevention. The first circuit member 6 and the second circuit member 9 may each be provided with one first electrode 5 and one second electrode 8, but preferably a plurality of first electrodes 5 and second electrodes 8 are provided at predetermined intervals.

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

<Example 1>
Urethane acrylate (product name: UA-5500T, manufactured by Shin-Nakamura Chemical Co., Ltd.), which is a radically polymerizable substance, 20 parts by mass, bis (acryloxyethyl) isocyanurate (product name: M-215, Toagosei Co., Ltd.) ) 15 parts by mass, dimethyloltricyclodecane diacrylate (product name: DCP-A, Kyoeisha Chemical Co., Ltd.) 5 parts by mass, and 2-methacryloyloxyethyl acid phosphate (product name: P-2M , Kyoeisha Chemical Co., Ltd.) 1 part by mass, a free radical generator benzoyl peroxide (product name: Nyper BMT-K, NOF Co., Ltd.) 8 parts by mass, and an insulating resin polyester urethane 60 parts by mass of a 40% by mass solution containing a resin (product name: UR4800, manufactured by Toyobo Co., Ltd.) was mixed and stirred to obtain a resin solution. At this time, the polyester urethane resin solution was prepared by dissolving the polyester urethane resin in a mixed solvent of toluene/methyl ethyl ketone=50/50.

On the other hand, a nickel layer having a thickness of 0.2 μm was formed on the surface of the polystyrene particles. Furthermore, a gold layer having a thickness of 0.04 μm was formed on the outside of this nickel layer. Thus, conductive particles having an average particle size of 4 μm were produced. The conductive particles were dispersed in the prepared resin solution at a ratio of 10 parts by volume to 100 parts by volume of the resin solution. 5-Methyltetrazole was dispersed therein at a rate of 1 part by volume with respect to 100 parts by volume of the resin solution. Furthermore, as a filler, silicone fine particles with an average particle size of 2 μm (product name: KMP-605, manufactured by Shin-Etsu Chemical Co., Ltd.) are dispersed at a rate of 20 parts by weight with respect to 100 parts by weight of the resin solution, and radical polymerization is performed. Thus, a coating solution of an adhesive composition was obtained which contained a volatile substance, a free radical generator, an insulating resin, conductive particles, a compound having a nitrogen-containing aromatic heterocycle, and a filler. This coating liquid was applied to a polyethylene terephthalate (PET) film (thickness: 50 μm) having one side subjected to release treatment using a coating device. The coating film was dried by hot air drying at 70° C. to form an anisotropically conductive adhesive film (thickness: 18 μm) made of the adhesive composition according to Example 1.

<Examples 2 to 5, Comparative Example 1>
Adhesive films according to Examples 2 to 5 were prepared in the same manner as in Example 1, except that in Example 1, a compound having a nitrogen-containing aromatic heterocycle shown in Table 1 was used instead of 5-methyltetrazole. was made. Further, an adhesive film according to Comparative Example 1 was produced in the same manner as in Example 1, except that 5-methyltetrazole was not added.

<Preparation of Copper Electrode Film Attached Body>
A copper electrode film member having a PET film and a copper film formed on the PET film was prepared as an adherend imitating a circuit member. On the copper film of the copper electrode film member, while heating the adhesive film so that the temperature reached 70° C., the whole was pressed at a pressure of 2 MPa per total connection area for 10 seconds. , a copper electrode film-attached body provided with a cured product of the adhesive composition derived from the adhesive film was obtained. FIG. 3 is a schematic cross-sectional view showing a copper electrode film-attached body. As shown in FIG. 3, the copper electrode film adhered body 13 has a copper film 15 formed on a PET film 14, and a cured product of an adhesive composition is formed on the surface 15a of the copper film 15 opposite to the PET film 14. 20 (consisting of cured adhesive component 22 and conductive particles 23) are further provided.

<Evaluation of connection reliability>
The patches obtained in Examples 1 to 5 and Comparative Example 1 were allowed to stand in an environment of 85° C. and 85% RH for 100 hours and subjected to a reliability test. Before and after the test, the appearance of the portion (attached portion) of the surface 15a of the copper film 15 opposite to the PET film 14 with which the cured product 20 comes into contact was visually observed. Connection reliability was evaluated by assigning A to almost no discoloration before and after the test, B to minor discoloration, and C to severe discoloration. Table 1 shows the evaluation results. If the evaluation result is A or B, it can be said that the connection reliability is excellent.

<Evaluation of connection resistance>
After attaching the anisotropically conductive adhesive films of Examples 1 to 5 and Comparative Example 1 to the copper electrode film, a flexible circuit board (FPC) was placed on the adhesive film on the opposite side of the copper electrode film. Then, while heating the adhesive film so that the ultimate temperature reached 170° C., the whole was pressed at a pressure of 2 MPa per total connection area for 10 seconds to obtain an adhesive film mounted body a (connected structure). The flexible circuit board had an electrode width of 150 μm, an inter-electrode space of 150 μm, an inter-electrode pitch of 300 μm, and a copper foil thickness of 18 μm. I used what I had. This adhesive film mounted body a was subjected to a reliability test by allowing it to stand in an environment of 85° C. and 85% RH for 100 hours. After the reliability test, the connection resistance of the adhesive film package a was measured and evaluated as A when it was 1Ω or less and B when it exceeded 1Ω. As shown in Table 1, the connection resistances of the adhesive film mounts a of Examples 1 to 5 were all good at 1Ω or less.

<Evaluation of adhesiveness>
After attaching the obtained anisotropically conductive adhesive films of Examples 1 to 5 and Comparative Example 1 to a PET film having a SiO ₂ film, a flexible circuit board was placed on the adhesive film on the opposite side of the PET film. (FPC) is placed, and while heating so that the temperature of the adhesive film reaches 170 ° C., the whole is pressed for 10 seconds at a pressure of 2 MPa per total connection area to obtain an adhesive film mounted body b (connected structure). rice field. The flexible circuit board had an electrode width of 150 μm, an inter-electrode space of 150 μm, an inter-electrode pitch of 300 μm, and a copper foil thickness of 18 μm. I used what I had. This adhesive film mounted body b was subjected to a reliability test by allowing it to stand in an environment of 85° C. and 85% RH for 100 hours. The adhesiveness (adhesive strength) of the adhesive film package b after the reliability test was measured, and evaluated as A when 4 N/cm or more and B when less than 4 N/cm. As shown in Table 1, all adhesive strengths were good at 4 N/cm or more.

DESCRIPTION OF SYMBOLS 1... Adhesive film (adhesive composition), 2... Adhesive component, 3... Conductive particles, 4... First substrate, 5... First electrode, 6... First circuit member, 7... Second substrate, 8... second electrode, 9... second circuit member, 10... circuit connection member (hardened adhesive composition), 11... connection structure.

Claims (4)

containing conductive particles and a compound having a nitrogen-containing aromatic heterocycle ,
The compound having a nitrogen-containing aromatic heterocyclic ring contains at least one selected from the group consisting of a compound having a tetrazole ring having an alkyl group and a compound having a triazole ring having a mercapto group, connecting circuit members. Adhesive composition used to a first circuit member having a first substrate and a first electrode provided on the first substrate;
a second circuit member having a second substrate and a second electrode provided on the second substrate;
a circuit connection member disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other;
A connection structure, wherein the circuit connection member is a cured product of the adhesive composition according to claim 1 . 3. The connection structure according to claim 2 , wherein said first electrode and said second electrode are made of copper, copper alloy, or copper oxide. A first circuit member having a first substrate and a first electrode provided on the first substrate; a second circuit member having a second substrate and a second electrode provided on the second substrate; Place the adhesive composition according to claim 1 between the two circuit members,
a step of crimping the first circuit member and the second circuit member through the adhesive composition to electrically connect the first circuit member and the second circuit member to each other; A method of manufacturing a connection structure, comprising:

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