JPWO2019142791A1 - Adhesive composition, connection structure and its manufacturing method - Google Patents

Abstract

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

Description

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

In recent years, electronic components have become smaller, thinner, and have higher performance, and at the same time, economical high-density mounting technology has been actively developed. It is difficult to connect an electronic component having a fine circuit electrode to a circuit member by using a conventional solder and a rubber connector. Therefore, a connection method using an anisotropically conductive adhesive composition having excellent resolution and a film (adhesive film) thereof as disclosed in Patent Documents 1 to 6 is often used. For example, when connecting the glass of a liquid crystal display (Liquid Crystal Display) to a circuit member such as a TAB (Tape Automated Bonding) or an FPC (Flexible Print Circuit), an anisotropic conductive adhesive containing conductive particles. By sandwiching the film between the electrodes facing each other, heating and pressurizing, the electrodes of both substrates are electrically connected to each other while maintaining the insulation between adjacent electrodes on the same substrate, resulting in fine circuit electrodes. The electronic component having the above and the circuit member are crimped and fixed.

Further, weight reduction, thinning, and high sensitivity of the module are required, and in a display module such as a liquid crystal display device and electronic paper, or a sensor substrate such as a touch panel, as an electrode 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 having low surface resistance instead of the conventional silver paste. Even in the anisotropically conductive adhesive film, studies have been made to optimize the raw materials and the like contained in the adhesive film for the purpose of reducing the connection resistance.

Japanese Unexamined Patent Publication No. 08-14821 Japanese Unexamined Patent Publication No. 08-124613 Japanese Unexamined Patent Publication No. 11-50032 Japanese Unexamined Patent Publication No. 2011-91044 Japanese Unexamined Patent Publication No. 2011-100605 Japanese Unexamined Patent Publication No. 2013-55058

Among the above-mentioned metals having low surface resistance, studies have been made for using easily 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 with time, and there is room for further improvement in terms of connection reliability.

Therefore, 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 having excellent connection reliability and a method for manufacturing the same.

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 heterocycle is 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, an oxazole ring and a pyrimidine ring. Thereby, the connection reliability can be further improved.

The adhesive composition is preferably used to connect the circuit members together.

Another aspect of the present invention is a first circuit member having a first substrate and a first electrode provided on the first substrate, and a second substrate and the second substrate. A circuit that is arranged between a second circuit member having a second electrode and a first circuit member and a second circuit member, and electrically connects the first electrode and the second electrode to each other. The circuit connecting member includes a connecting member, and the circuit connecting member is a connecting structure which is a cured product of the above-mentioned adhesive composition.

The first electrode and the second electrode are preferably copper, a copper alloy, or a copper oxide.

Another aspect of the present invention is a first circuit member having a first substrate and a first electrode provided on the first substrate, and a second substrate and the second substrate. The above-mentioned adhesive composition is arranged between the second circuit member having the second electrode, and the first circuit member and the second circuit member are separated from each other via the above-mentioned adhesive composition. It is a method of manufacturing a connection structure including a step of crimping to electrically connect a first circuit member and a second circuit member.

According to the present invention, it is possible to provide an adhesive composition capable of suppressing an increase in connection resistance and improving connection reliability. Further, the present invention can provide a connection structure having excellent connection reliability and a method for manufacturing the same.

It is a schematic cross-sectional view which shows the adhesive film which concerns on one Embodiment. It is a schematic cross-sectional view which shows the manufacturing method of the connection structure which concerns on one Embodiment. It is a schematic cross-sectional view which shows the copper electrode film sticking body used in an Example.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

The adhesive composition according to one embodiment contains an adhesive component and conductive particles dispersed in the adhesive component. The adhesive component is defined as a non-volatile component 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 that coats the polymer particles. The polymer particles are preferably covered with a metal layer substantially entirely on the surface thereof, but a part of the surface of the polymer particles is not covered with the metal layer as long as the function as a circuit connection material is maintained. It 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 is preferably 1 μm or more, 40 μm or less, and may be 1 to 40 μm. From the viewpoint of high-density mounting, the average particle size of the polymer particles may be more preferably 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 may be more preferably 2 μm or more, and may be 20 μm or less. It may be 2 to 20 μm. The average particle size of the polymer particles can be obtained as an average value by observing with a scanning electron microscope (SEM) and measuring the particle size of 300 polymer particles.

The metal layer may be formed 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 the insulating property, the conductive particles may further have an insulating layer provided on the outside of the metal layer and covering the metal layer. The insulating layer may be a layer formed of an insulating material such as silica or acrylic.

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

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

The radically polymerizable substance is a substance having a functional group that is polymerized by a radical, and examples thereof include an acrylate compound, a methacrylate compound, and a maleimide compound. 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 the acrylate compound and methacrylate compound include urethane acrylate, urethane methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, and dimethylol tricyclodecane diacrylate. , Trimethylol Propane Triacrylate, Tetramethylol Methan Tetraacrylate, 2-Hydroxy-1,3-Diacryloxypropane, 2,2-Bis [4- (Acryloxymethoxy) Phenyl] Propane, 2,2-Bis [4 -(Acryloxipolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, bis (acryloxyethyl) isocyanurate, ε-caprolactone-modified tris (acryloxyethyl) isocyanurate, and tris (acryloxyethyl) ) Isocyanurate can be mentioned. The radically polymerizable substance may be used alone or in combination of two or more. The radically polymerizable substance is preferably urethane acrylate or urethane methacrylate from the viewpoint of adhesiveness.

As the radically polymerizable substance, from the viewpoint of improving heat resistance, urethane acrylate or urethane methacrylate and a radically polymerizable substance that alone exhibits Tg of 100 ° C. or higher when crosslinked with an organic peroxide are used in combination. Is particularly preferred. Such a radically polymerizable substance may be a compound having a dicyclopentenyl group and / or a tricyclodecanyl group, and is 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, 1,000,000 mPa · s or less, 100,000 to 1,000,000 mPa · s, and preferably 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 decomposes by heat or light to generate free radicals, and is, for example, a peroxide compound or an azo compound. The free radical generator is appropriately selected according to the target 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. is there. 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 a decomposition accelerator, an inhibitor, or the like.

The adhesive component of the present 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 heterocycle (hereinafter, also simply referred to as “heterocyclic compound”) is a compound having an aromatic heterocycle containing one or more nitrogen atoms in the ring. A nitrogen-containing aromatic heterocycle (hereinafter, also simply referred to as “heterocycle”) is composed of at least two types 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 heterocycle contains, for example, 1 to 4 nitrogen atoms, preferably 2 to 4 nitrogen atoms. When the heterocycle contains one nitrogen atom, the heterocycle preferably further contains the above other atoms in addition to the carbon atom and the nitrogen atom.

The heterocycle is preferably a compound having a 5-membered ring or a 6-membered ring, and more preferably a compound having a 5-membered ring (azole). Examples of the 5-membered ring include a pyrazole ring, an imidazole ring, a triazole ring, a tetrazole ring, a thiazole ring, a thiadiazole ring, an oxazole ring and the like. Examples of the 6-membered ring include a pyrimidine ring and the like.

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

The heterocycle may be unsubstituted or may have a substituent (the hydrogen atom bonded to the atom constituting the heterocycle is substituted). When the heterocycle has a substituent, the substituent may be a hydrocarbon group or an organic group containing a sulfur atom, an oxygen atom and the like. The hydrocarbon group may be an alkyl group or the like. The 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 or the like.

The heterocyclic compound may have a nitrogen-containing aromatic heterocycle composed of a monocycle, and may contain, for example, an aromatic ring composed only of hydrocarbons (for example, a substituted or unsubstituted benzene ring) and the above-mentioned above-mentioned heterocyclic ring. It may have a polycycle fused with a nitrogen aromatic heterocycle. Such a polycycle may be, for example, a benzimidazole ring, a benzotriazole ring, a benzothiazole ring, a benzoxazole ring or the like.

Specific examples of the heterocyclic compound include 5-methyltetrazole, 5-amino-1H-tetrazole, 3-mercapto-1,2,4-triazole, benzotriazole, 2-aminopyrimidine, and 5,6-dimethylbenzimidazole. , 2-Amino-5-mercapto-1,3,4-thiazazole, 2-mercaptopyrimidine, 2-mercaptobenzoxazole, 2-mercaptobenzthiazole, 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, based on 100 parts by volume of the adhesive component, from the viewpoint of suppressing an increase in connection resistance and further improving connection reliability. It is 0.1 part by volume or more, more preferably 0.2 part by volume or more, preferably 5 part by volume or less, more preferably 2 part by volume or less, still more preferably 1 part by volume or less. is there.

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

Thermosetting resins include, for example, epoxy resin, cyanate ester resin, maleimide resin, allylnadiimide resin, phenol resin, urea resin, alkyd resin, acrylic resin, unsaturated polyester resin, diallylphthalate resin, silicone resin, resorsinol formaldehyde resin. , Xylene resin, furan resin, polyurethane resin, ketone resin, triallyl cyanurate resin, polyisocyanate resin, tris (2-hydroxyethyl) isocyanurate-containing resin, triallyl trimeritato-containing resin, cyclopentadiene. Examples thereof include a thermosetting resin synthesized from the above, a thermosetting resin obtained by quantifying aromatic isocyanate. The thermosetting resin is used alone or in combination of two or more. 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 type curing agent. The catalytic curing agent may be hydrazide, boron trifluoride-amine complex, sulfonium salt, amineimide, diaminomaleonitrile, polyamine salt, dicyandiamide or the like, or may be a modified product thereof. The curing agent may be a heavy addition type curing agent such as polyamine, polymercaptan, polyphenol, acid anhydride and the like. As the curing agent, a heavy addition type curing agent and a catalytic type curing agent can be used in combination. As the curing agent, these may be used alone or in combination of two or more. The content of the curing agent may be 0.5% by mass or more, 15% by mass or less, and 0.5 to 15% by mass based on the total amount of the adhesive components.

The curing agent is obtained by coating the above-mentioned curing agent with a polymer compound such as polyurethane or polyester, a metal thin film such as Ni or Cu, or an inorganic compound such as calcium silicate and microencapsulating it. May be good. Such a curing agent is preferable because the pot life can be extended.

In another embodiment, the adhesive component contains the above-mentioned radically polymerizable substance, a free radical generator, a thermosetting resin, and a 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 components. It may be 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 antiaging agent, a coloring agent, a flame retardant agent, a thixotropic agent, a coupling agent, and the like. You can also.

The adhesive composition may be in the form of a paste, and may be preferably an adhesive film formed in the form of a film from the viewpoint of handleability. FIG. 1 is a schematic cross-sectional view showing a film-like adhesive composition (adhesive film) according to an embodiment. As shown in FIG. 1, in one embodiment, the adhesive film 1 is composed of a layer composed of an adhesive component 2 and conductive particles 3 dispersed in the adhesive component 2. The adhesive component 2 and the conductive particles 3 may be the above-mentioned adhesive component and conductive particles in one embodiment. The thickness of the adhesive film 1 may be, for example, 10 μm or more, 50 μm or less, and 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 enhance the film-forming property. The insulating resin may be polystyrene, polyethylene, polyvinyl butyral, polyvinylformal, polyimide, polyamide, polyvinyl chloride, polyphenylene oxide, urea resin, phenoxy resin, polyimide resin, polyester urethane resin, etc., further improving connection reliability. From the viewpoint of enhancing, a high molecular weight phenoxy resin having a weight average molecular weight of 10,000 or more determined by high-speed liquid chromatography (HPLC) may be used. The adhesive component may contain a resin obtained by modifying these resins with a radically polymerizable functional group, or may contain a mixture of these resins and a styrene resin or an acrylic resin for adjusting the melt viscosity or the like. You may. In another embodiment, the adhesive component may contain rubber to enhance film formability.

The adhesive film may also have a multi-layer structure. 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 not containing the above. 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 conductive particles can be efficiently arranged on the electrodes. The adhesive film may further have an adhesive layer that exhibits high adhesiveness to each of the circuit members to be connected in consideration of adhesiveness to the circuit member.

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

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

Then, the adhesive film 1 is cured while pressurizing the whole 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 of curing the adhesive film 1 may be a method of heating, or a method of using light irradiation in combination with heating. The heating may be performed at, for example, 100 to 170 ° C. Pressurization and heating (irradiation with light 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 product of the adhesive composition constituting the adhesive film 1.

In the present embodiment, the adhesive film 1 is arranged between the first circuit member 6 and the second circuit member 9, but as another embodiment, a paste-like adhesive composition is used instead of the adhesive film. The object may be applied onto the first circuit member 6 and / or the second circuit member 9.

As shown in FIG. 2B, the connection structure 11 according to the embodiment thus obtained has the first substrate 4 and the first electrode 5 provided on the first substrate 4. The first circuit member 6 having the first circuit member 6, the second circuit member 9 having the second electrode 8 provided on the second substrate 7 and the second substrate 7, the first circuit member 6 and the second A circuit connecting member 10 which is arranged between the circuit member 9 and electrically connects the first electrode 5 and the second electrode 8 to each other is provided. The circuit connection member 10 is composed of a cured product of the 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 as or different from each other, and are provided on, for example, a flexible substrate containing a thermoplastic resin, a glass substrate, or a glass substrate and the glass substrate. It may be a composite substrate having an insulating film.

The flexible substrate is, for example, an organic substrate formed 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 treatment 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 the handling and transportation of the flexible substrate, a reinforcing material selected from a glass material, SUS and the like may be attached to the organic substrate.

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

When a conventional circuit connection material is used, the electrodes on the flexible substrate may be easily broken or cracked due to heating and pressurization for crimping between circuit members. Further, regarding the connection of electrodes that are difficult to form a sufficient electrical connection, it is necessary to crimp the circuit member under conditions of lower temperature or lower stress in order to suppress damage to the electrodes. The adhesive film 1 of the present embodiment may also have an advantageous effect in these respects as compared with the conventional material.

The glass substrate may be made of soda glass, quartz glass, or the like. From the viewpoint of preventing damage due to external stress, a substrate made of these materials may be chemically strengthened. The composite substrate may have a glass substrate and an insulating film provided on the surface of the glass substrate and composed of polyimide or a colored organic or inorganic material for decoration. In the composite substrate, the 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 containing. Alternatively, the first substrate 4 may be an IC chip or a flexible substrate, and the second substrate 7 may be a glass substrate or a 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-mentioned 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 above-mentioned adhesive film 1 is used for FOP (Film on Plastic substrate) connection.

When the second substrate 7 is a flexible substrate, the first circuit member 6 is an electronic component such as an active element such as a semiconductor chip, a transistor, a die, a thyristor, a capacitor, a resistor, or a passive element such as a coil. It may be a printed circuit board or a glass substrate on which an ITO or the like is formed into a circuit. When the first substrate 4 is a semiconductor chip or a glass substrate, the tips of bumps or gold wires formed by plating are melted by a torch or the like to form gold balls, and the balls are crimped onto the electrode pads. A protruding electrode such as a wire bump obtained by cutting a wire is provided, and this can be used as the first circuit member 6.

Examples of the electrode material forming the first electrode 5 and the second electrode 8 include metals such as Ag, Ni, Al, Au, Cu, Ti, and Mo, and transparent such as ITO, IZO, silver nanowires, and carbon nanotubes. Examples include conductors. 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 formed of copper, a copper alloy, or a copper oxide from the viewpoint of reducing connection resistance and availability. From the viewpoint of preventing disconnection, surface layers such as an oxide or nitride film, an alloy film, and an organic film may be further provided on the first electrode 5 and the second electrode 8. The first circuit member 6 and the second circuit member 9 may be provided with one first electrode 5 and one second electrode 8, but preferably, a plurality of first electrodes 5 are provided. And the second electrode 8 are provided at predetermined intervals, respectively.

Hereinafter, the present invention will be described in more detail 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 Industry Co., Ltd.), which is a radically polymerizable substance, 20 parts by mass, bis (acryloxyethyl) isocyanurate (product name: M-215, Toa Synthetic Co., Ltd.) 15 parts by mass, dimethylol tricyclodecandiacrylate (product name: DCP-A, manufactured by 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, benzoyl peroxide (product name: Niper BMT-K, manufactured by Nippon Yushi Co., Ltd.) 8 parts by mass, which is a free radical generator, and polyester urethane which is an insulating resin. A resin solution was obtained by mixing with 60 parts by mass of a 40% by mass solution containing a resin (product name: UR4800, manufactured by Toyo Spinning Co., Ltd.) and stirring. At this time, the solution of the polyester urethane resin 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. Further, a gold layer having a thickness of 0.04 μm was formed on the outside of the nickel layer. As a result, 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 with respect to 100 parts by volume of the resin solution. 5-Methyltetrazole was dispersed therein at a ratio of 1 part by volume with respect to 100 parts by volume of the resin solution. Further, as a filler, silicone fine particles having an average particle size of 2 μm (product name: KMP-605, manufactured by Shin-Etsu Chemical Co., Ltd.) are dispersed in a ratio of 20 parts by mass with respect to 100 parts by mass of the resin solution for radical polymerization. A coating liquid of an adhesive composition containing a sex substance, a free radical generator, an insulating resin, conductive particles, a compound having a nitrogen-containing aromatic heterocycle, and a filler was obtained. This coating liquid was applied to a polyethylene terephthalate (PET) film (thickness 50 μm) having a mold release treatment on one side 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) composed of the adhesive composition according to Example 1.

<Examples 2 to 5, Comparative Example 1>
The adhesive film according to Examples 2 to 5 in the same manner as in Example 1 except that the compound having a nitrogen-containing aromatic heterocycle shown in Table 1 was used instead of 5-methyltetrazole in Example 1. Was produced. 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 in Example 1.

<Preparation of copper electrode film sticker>
As an adherend imitating a circuit member, a copper electrode film member having a PET film and a copper film formed on the PET film was prepared. The produced adhesive film is heated on the copper film of the copper electrode film member so that the reaching temperature of the adhesive film reaches 70 ° C., and the whole is pressurized for 10 seconds at a pressure of 2 MPa per total connection area. , A copper electrode film patch having a cured product of an adhesive composition derived from an adhesive film was obtained. FIG. 3 is a schematic cross-sectional view showing a copper electrode film affixed body. As shown in FIG. 3, in the copper electrode film sticking body 13, a copper film 15 is formed on the PET film 14, and a cured product of the adhesive composition is formed on the surface 15a of the copper film 15 opposite to the PET film 14. 20 (composed of a cured product 22 as an adhesive component and conductive particles 23) is further provided.

<Evaluation of connection reliability>
The obtained patches of Examples 1 to 5 and Comparative Example 1 were allowed to stand in an environment of 85 ° C. and 85% RH for 100 hours to be subjected to a reliability test. With respect to the copper electrode film affixed body 13 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 in contact with the cured product 20 was visually observed. The connection reliability was evaluated with A as the one in which almost no discoloration was observed before and after the test, B as the one in which the discoloration was observed but the degree was small, and C as the one in which the severe discoloration was observed. The evaluation results are shown in Table 1. If the evaluation result is A or B, it can be said that the connection reliability is excellent.

<Evaluation of connection resistance>
After the idiosyncratic adhesive films of Examples 1 to 5 and Comparative Example 1 were attached to the copper electrode film, the flexible circuit board (FPC) was placed on the adhesive film on the opposite side of the copper electrode film. An adhesive film mounting body a (connection structure) was obtained by pressurizing the entire adhesive film for 10 seconds at a pressure of 2 MPa per total connection area while heating the adhesive film so that the temperature reached was 170 ° C. As a flexible circuit board, the electrode width is 150 μm, the space between electrodes is 150 μm, the pitch between electrodes is 300 μm, the copper foil thickness is 18 μm, and Ni (thickness 3 μm) and Au (thickness 0.01 μm) are formed on the surface. I used the one that is. The adhesive film mounting body a was allowed to stand in an environment of 85 ° C. and 85% RH for 100 hours for a reliability test. The connection resistance of the adhesive film mounting body a after the reliability test was measured, and those having 1Ω or less were evaluated as A, and those exceeding 1Ω were evaluated as B. As shown in Table 1, the connection resistance of the adhesive film mounting bodies a of Examples 1 to 5 was as good as 1Ω or less.

<Evaluation of adhesiveness>
After the obtained isotropic adhesive films of Examples 1 to 5 and Comparative Example 1 are attached to a PET film having a SiO ₂ film, a flexible circuit substrate is placed on the adhesive film on the opposite side of the PET film. (FPC) is placed on the film, and while heating so that the reaching temperature of the adhesive film reaches 170 ° C., the entire area is pressurized at a pressure of 2 MPa per total connection area for 10 seconds to obtain an adhesive film mounting body b (connection structure). It was. As a flexible circuit board, the electrode width is 150 μm, the space between electrodes is 150 μm, the pitch between electrodes is 300 μm, the copper foil thickness is 18 μm, and Ni (thickness 3 μm) and Au (thickness 0.01 μm) are formed on the surface. I used the one that is. The adhesive film mounting body b was allowed to stand in an environment of 85 ° C. and 85% RH for 100 hours to be subjected to a reliability test. The adhesiveness (adhesive strength) of the adhesive film mounting body b after the reliability test was measured, and those having 4 N / cm or more were evaluated as A and those having less than 4 N / cm as B. As shown in Table 1, the adhesive strength was as good as 4 N / cm or more.

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 (cured product of adhesive composition), 11 ... connection structure.

Claims (6)

An adhesive composition containing conductive particles and a compound having a nitrogen-containing aromatic heterocycle. The nitrogen-containing aromatic heterocycle is 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, an oxazole ring and a pyrimidine ring, according to claim 1. Adhesive composition. The adhesive composition according to claim 1 or 2, which is used for connecting circuit members to each other. A first circuit board having a first substrate and a first electrode provided on the first substrate, and a first circuit member.
A second circuit board having a second substrate and a second electrode provided on the second substrate, and a second circuit member.
A circuit connecting member arranged between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other is provided.
The circuit connection member is a connection structure which is a cured product of the adhesive composition according to any one of claims 1 to 3. The connection structure according to claim 4, wherein the first electrode and the second electrode are made of copper, a copper alloy, or a copper oxide. A first circuit member having a first substrate and a first electrode provided on the first substrate, and a second having a second substrate and a second electrode provided on the second substrate. The adhesive composition according to any one of claims 1 to 3 is arranged between the two circuit members.
A step of crimping the first circuit member and the second circuit member via the adhesive composition to electrically connect the first circuit member and the second circuit member to each other. A method for manufacturing a connection structure.

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