JP6972614B2 - An anisotropic conductive film, a connection structure, and a method for manufacturing the connection structure. - Google Patents

Description

The present invention relates to an anisotropic conductive film, a connection structure, and a method for manufacturing the connection structure.

Conventionally, for example, in the connection between a liquid crystal display and a tape carrier package (TCP), the connection between a flexible printed circuit board (FPC) and TCP, or the connection between an FPC and a printed wiring board, conductive particles are dispersed in an adhesive film. An anisotropic conductive film is used. Also, when mounting a semiconductor silicon chip on a substrate, so-called chip-on-glass (COG), in which the semiconductor silicon chip is directly mounted on the substrate, is performed instead of the conventional wire bonding, and this is also anisotropic conduction. Sex films are used.

Further, in recent years, in the field of precision electronic equipment, the density of circuits has been increasing, and the electrode width and the electrode spacing have become extremely narrow. For this reason, there are problems such as wiring falling off, peeling, and misalignment under the connection conditions of the circuit connection adhesive using the conventional epoxy resin system, and COG is caused by the difference in thermal expansion between the chip and the substrate. There was a problem that warpage occurred. Furthermore, it is necessary to improve the throughput in order to reduce the cost, and an adhesive that can be cured at a low temperature (100 to 170 ° C) and in a short time (within 10 seconds), in other words, an adhesive that can be cured at a low temperature and quickly is required. Has been done.

Examples of the epoxy resin polymerization system capable of low-temperature rapid curing include cationic curing of epoxy resins. In this case, as the cationic polymerization initiator, for example, a polymerization initiator of a cationically polymerizable substance having a potential containing a sulfonium salt as a main component is widely used (see Patent Document 1).

However, in the cationic polymerization initiator containing a sulfonium salt as a main component, SbF ₆ , AsF ₆ , PF ₆ and BF ₄ are used as counter anions, and in these cationic polymerization initiators, the fluorine atom of the counter anion is boron, respectively. Since it is directly bonded to an atom, a phosphorus atom, or an antimony atom, it loses its stability when exposed to a high temperature or high humidity state, and fluorine ions are easily separated and generated. Therefore, the above-mentioned sulfonium salt complex has a problem that a large amount of fluorine ions are generated when exposed to a high temperature and high humidity state during and after cationic polymerization, and corrodes metal wiring, ITO wiring and a connection pad.

On the other hand, as a polymerization system of an epoxy resin having excellent corrosion resistance, adhesive strength, and connection reliability, anion curing of the epoxy resin can be mentioned. In this case, dicyandiamide, an amine salt, a modified imidazole compound and the like have been proposed as potential anionic polymerization initiators. Further, studies have been conducted in which the surface of the powdered amine compound is reacted with isocyanate to inactivate the surface of the amine compound to impart potential to the curing agent (see Patent Document 2). Further, a microcapsule type curing agent in which a powdered amine compound is encapsulated and liquefied by reacting with isocyanate in an epoxy resin has also been proposed (see Patent Document 3).

However, in the case of conventional anionic polymerization initiators, those having excellent storage stability have low curability and require high temperature or a long time for curing, while those having high curability have low storage stability, for example. It needs to be stored at a low temperature such as -20 ° C.

Further, studies have been made to cure the epoxy resin by generating a base by the action of light. In this case, the resin composition is excellent in storage stability unless it is irradiated with light such as ultraviolet rays, and a corrosive substance is not generated unlike the cationic polymerization initiator (see Patent Documents 4 and 5).

Japanese Unexamined Patent Publication No. 2004-217551 Special Publication No. 58-55970 Japanese Unexamined Patent Publication No. 1-70523 Japanese Unexamined Patent Publication No. 2005-264156 Japanese Unexamined Patent Publication No. 2009-280785

However, it has been difficult to simultaneously satisfy corrosion resistance, storage stability, and low-temperature fast-curing property by the conventionally provided methods. In particular, the method of curing an epoxy resin by generating a base by the action of light has relatively good corrosion resistance and storage stability, but the wavelength of ultraviolet rays for activating the curing agent is limited to a short wavelength. Good low-temperature fast-curing property can be obtained because of the fact that the strength of the base that can be generated is limited, and that the reaction that generates the base by the action of light is not carried out rapidly. There was a problem that it was difficult.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to achieve both low-temperature rapid curing and storage stability, and to obtain good connection reliability and good adhesive strength. It is an object of the present invention to provide a film, a connecting structure, and a method for manufacturing the connecting structure.

In view of the above problems, the present inventors have conducted various studies, and as a result, an anisotropic conductive film containing a specific curing agent that generates a base by light together with an epoxy compound, an oxetane compound, and a thiol compound is used. We have found that the problem can be solved and have completed the present invention.

［一般式（１）中、ＲはＣＨ_３又はＨを示し、Ｘはアミジン類、グアニジン類、又はホスファゼン誘導体から選ばれる塩基類を示す。］ That is, the present invention is an anisotropic conductive film interposed between the circuit electrodes facing each other and used to pressurize the circuit electrodes and electrically connect the electrodes in the pressurizing direction. (A) An adhesive layer containing a film-forming material, (b) an epoxy compound or an oxetane compound, (c) a thiol compound, and (d) a curing agent that generates a base by light is provided, and the above (d) light is used. Provided is an anisotropic conductive film in which a curing agent that generates a base contains a carboxylate represented by the following general formula (1).

[In the general formula (1), R represents CH ₃ or H, and X represents a base selected from amidines, guanidines, or phosphazene derivatives. ]

By having the above-mentioned structure, the anisotropic conductive film of the present invention has both low-temperature short-time curability (low-temperature quick-curing property) and storage stability, and has excellent connection reliability and adhesive strength. It is possible to realize a film.

The amidines are the compound represented by the following formula (2), the guanidines are the compounds represented by the following formula (3-1) or the formula (3-2), and the phosphazene derivative. Is preferably a compound represented by the following formula (4-1), formula (4-2), formula (4-3), or formula (4-4). When these compounds are used, since the base generated by ultraviolet irradiation has high basicity, low-temperature fast curing can be expected, and the cured product of the anisotropic conductive film has high adhesive strength. It is possible to obtain a connection structure in which circuit members are more firmly bonded to each other.

Further, the thiol compound (c) is preferably a polythiol compound having 3 or more thiol groups. When the above polythiol compound is used, it becomes possible to form a three-dimensional crosslinked structure, and the physical characteristics of the anisotropic conductive film after curing are improved, and low resistance can be expected.

The content of the curing agent that generates a base by (d) light in the adhesive layer is 0.5 with respect to 100 parts by mass of the total of (b) an epoxy compound or an oxetane compound and (c) a thiol compound. It is preferably about 30 parts by mass. By containing (d) a curing agent that generates a base by light in the above range, (b) both the rapid curability of the epoxy compound or the oxetane compound and the thiol compound and the cured property of the cured product of these compounds are compatible. Is possible.

Further, in the anisotropic conductive film of the present invention, the adhesive layer comprises conductive particles in a total volume of (a) a film forming material, (b) an epoxy compound or an oxetane compound, and (c) a thiol compound. It is preferable to contain 0.1 to 50 parts by volume with respect to the part. In this case, when the connection structure is manufactured using the anisotropic conductive film, it becomes easy to connect the circuit electrodes with a low connection resistance while preventing a short circuit of the circuit.

The present invention also uses the cured product of the anisotropic conductive film of the present invention to provide a first circuit member provided with a bump electrode and a second circuit provided with a circuit electrode corresponding to the bump electrode. Provided is a connection structure in which a member is adhered and the bump electrode and the circuit electrode are electrically connected.

The present invention is also different from the present invention between the main surface of the first circuit member provided with the bump electrode and the main surface of the second circuit member provided with the circuit electrode corresponding to the bump electrode. A polar conductive film is arranged, the anisotropic conductive film is heated and pressurized via the first circuit member and the second circuit member, and further, ultraviolet rays are irradiated from the back surface of the second circuit member to cure the electrode. A connection structure in which the first circuit member and the second circuit member are adhered to each other via a cured product of the heterogeneous conductive film, and the bump electrode and the circuit electrode are electrically connected. Provides a method of manufacturing a body.

According to the method for manufacturing this connection structure, the anisotropic conductive film is heated and pressurized via the first circuit member and the second circuit member, and ultraviolet rays are further irradiated from the back surface of the second circuit member. Therefore, the manufacturing time of the connection structure is the same as that of only heating and pressurizing. Therefore, even if the ultraviolet irradiation step is added, it becomes possible to manufacture the connected structure without causing a decrease in throughput.

Further, the present invention corresponds to the circuit electrode after arranging the heterogeneous conductive film of the present invention on the second circuit member provided with the circuit electrode and irradiating the anisotropic conductive film with ultraviolet rays. The first circuit member provided with the bump electrode is arranged on the idiosyncratic conductive film, and the idiosyncratic conductive film is heated and pressurized via the first circuit member and the second circuit member. It is cured, and the first circuit member and the second circuit member are adhered to each other through the cured product of the anisotropic conductive film, and the bump electrode and the circuit electrode are electrically connected to each other. A method for manufacturing a structure is provided.

According to the method for manufacturing this connection structure, ultraviolet rays are emitted from above the anisotropic conductive film attached to the second circuit member, and then the first circuit member is arranged and crimped. It is possible to uniformly irradiate ultraviolet rays even on a glass member or a plastic member having a metal wiring circuit that shields it, and even when a light-shielding circuit member such as polyimide is used, the adhesive surface between the circuit members It becomes possible to irradiate ultraviolet rays.

According to the present invention, a method for manufacturing an anisotropic conductive film, a connection structure, and a connection structure capable of achieving both low-temperature rapid curing and storage stability, and obtaining good connection reliability and good adhesive strength can be obtained. Can be provided. By using the anisotropic conductive film of the present invention, connection reliability between facing circuit members can be ensured even when mounted at a low temperature. Further, the method for manufacturing a connection structure of the present invention can satisfactorily produce a connection structure even when a substrate having metal wiring and a substrate having a light-shielding property are used.

It is a schematic cross-sectional view which shows one Embodiment of the connection structure which concerns on this invention. It is a schematic sectional drawing which shows one Embodiment of the anisotropic conductive film which concerns on this invention. It is a schematic sectional drawing which shows the other embodiment of the anisotropic conductive film which concerns on this invention. It is a schematic cross-sectional view which shows the manufacturing process of the connection structure shown in FIG. It is a schematic cross-sectional view which shows the subsequent process of FIG.

Hereinafter, preferred embodiments of the anisotropic conductive film and the connecting structure according to the present invention and the method for manufacturing the connecting structure will be described with reference to the drawings.

[Structure of connection structure]
FIG. 1 is a schematic cross-sectional view showing an embodiment of the connection structure according to the present invention. As shown in the figure, the connection structure 1 is a cured product 4 of an anisotropic conductive film connecting the first circuit member 2 and the second circuit member 3 facing each other and the circuit members 2 and 3. It is configured with and.

The first circuit member 2 is, for example, a tape carrier package (TCP), a printed wiring board, a semiconductor silicon chip, or the like. The first circuit member 2 has a plurality of bump electrodes 6 on the mounting surface 5a side of the main body 5. The bump electrode 6 has, for example, a rectangular shape in a plan view, and has a thickness of, for example, 3 μm or more and less than 18 μm. For example, Au or the like is used as the material for forming the bump electrode 6, and the particles P are more easily deformed than the conductive particles P contained in the cured product 4 of the anisotropic conductive film. An insulating layer may be formed on the mounting surface 5a where the bump electrode 6 is not formed.

The second circuit member 3 is, for example, a glass substrate or a plastic substrate whose circuit is formed of ITO, IZO, metal or the like used for a liquid crystal display, a flexible printed circuit board (FPC), a ceramic wiring board, or the like. As shown in FIG. 1, the second circuit member 3 has a plurality of circuit electrodes 8 corresponding to the bump electrodes 6 on the mounting surface 7a side of the main body 7. Like the bump electrode 6, the circuit electrode 8 has a rectangular shape, for example, in a plan view, and has a thickness of, for example, about 100 nm. The surface of the circuit electrode 8 is one selected from, for example, gold, silver, copper, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, indium tin oxide (ITO), and indium zinc oxide (IZO). It is composed of two or more kinds of materials. Also on the mounting surface 7a, an insulating layer may be formed on a portion where the circuit electrode 8 is not formed.

The cured product 4 of the anisotropic conductive film is a layer formed by using the anisotropic conductive film 11 (see FIG. 2) described later, and is a first region 9 formed by curing the conductive adhesive layer 13. And a second region 10 formed by curing the insulating adhesive layer 14. In the present embodiment, the first region 9 is located on the second circuit member 3 side, and the second region 10 is located on the first circuit member 2 side. In the present embodiment, for convenience of explanation, the layer in which the conductive particles P are dispersed is referred to as a conductive adhesive layer, and the layer in which the conductive particles P are not dispersed is referred to as an insulating adhesive layer. The constituent adhesive components themselves are non-conductive.

The conductive particles P are interposed between the bump electrode 6 and the circuit electrode 8 in a state of being slightly flattened by crimping. As a result, an electrical connection between the bump electrode 6 and the circuit electrode 8 is realized. Further, the conductive particles P are separated between the adjacent bump electrodes 6 and 6 and between the adjacent circuit electrodes 8 and 8, and between the adjacent bump electrodes 6 and 6 and between the adjacent circuit electrodes 8 and 8. Electrical insulation is realized.

[Structure of anisotropic conductive film]
FIG. 2 is a schematic cross-sectional view showing an embodiment of the anisotropic conductive film according to the present invention, and shows the anisotropic conductive film used for the connection structure shown in FIG. As shown in the figure, the anisotropic conductive film 11 includes a release film 12, a conductive adhesive layer 13 composed of an adhesive layer in which conductive particles P are dispersed, and an adhesive in which conductive particles P are not dispersed. The insulating adhesive layer 14 composed of layers is laminated in this order.

Further, FIG. 3 is a schematic cross-sectional view showing another embodiment of the anisotropic conductive film according to the present invention. As shown in FIG. 3, the anisotropic conductive film 21 is composed of a release film 12 and a conductive adhesive layer 13 composed of an adhesive layer in which conductive particles P are dispersed. As shown in FIG. 3, the anisotropic conductive film of the present invention may have only one layer of the conductive adhesive layer 13 without the insulating adhesive layer 14 as the adhesive layer. Here, the composition of the conductive adhesive layer 13 in the anisotropic conductive film 21 shown in FIG. 3 is the same as the composition of the conductive adhesive layer 13 in the anisotropic conductive film 11 shown in FIG. However, the thickness of the conductive adhesive layer 13 in the anisotropic conductive film 21 shown in FIG. 3 is the thickness of the conductive adhesive layer 13 and the insulating adhesive layer 14 in the anisotropic conductive film 11 shown in FIG. Similar to total thickness. Further, when the connection structure is formed by using the anisotropic conductive film 21 shown in FIG. 3, the cured product 4 of the anisotropic conductive film shown in FIG. 1 cures the conductive adhesive layer 13. It is composed of only the first region 9 of the above.

Hereinafter, each component of the anisotropic conductive film shown in FIGS. 2 and 3 will be described in detail.

The release film 12 is made of, for example, polyethylene terephthalate (PET), polyethylene, polypropylene or the like. The release film 12 may contain any filler. Further, the surface of the release film 12 may be subjected to a mold release treatment, a plasma treatment, or the like.

The adhesive layer forming the conductive adhesive layer 13 and the insulating adhesive layer 14 is at least (a) a film forming material (hereinafter, also referred to as “(a) component”) and (b) an epoxy. A compound or an oxetane compound (hereinafter, also referred to as “(b) component”), a (c) thiol compound (hereinafter, also referred to as “(c) component”), and (d) a curing agent that generates a base by light (hereinafter, also referred to as “component”). , Also referred to as "(d) component").

(A) The film-forming material has an action of facilitating the handling of a low-viscosity composition containing the above-mentioned (b) epoxy compound or oxetane compound, (c) thiol compound, and (d) a curing agent that generates a base by light. It is a polymer having. By using the film forming material, it is possible to obtain an anisotropic conductive film which is easy to handle by suppressing the film from being easily torn, cracked or sticky.

As the film forming material of the component (a), a thermoplastic resin is preferably used, and a phenoxy resin, a polyvinylformal resin, a polystyrene resin, a polyvinylbutyral resin, a polyester resin, a polyamide resin, a xylene resin, a polyurethane resin, a polyacrylic resin, etc. Examples thereof include polyester urethane resin. Further, these polymers may contain siloxane bonds or fluorine substituents. These resins can be used alone or in admixture of two or more. Among the above resins, it is preferable to use a phenoxy resin from the viewpoint of adhesive strength, compatibility, heat resistance, and mechanical strength.

(A) The larger the molecular weight of the thermoplastic resin used as the component, the easier it is to obtain film formability, and the melt viscosity that affects the fluidity of the anisotropic conductive film can be set in a wide range. The molecular weight of the thermoplastic resin is preferably 5000 to 150,000, and particularly preferably 1000 to 80000 in terms of weight average molecular weight. When the weight average molecular weight is 5000 or more, good film forming property is easily obtained, and when it is 150,000 or less, good compatibility with other components is easily obtained.

In the present invention, the weight average molecular weight is a value measured by a gel permeation chromatograph (GPC) using a calibration curve made of standard polystyrene according to the following conditions.
(Measurement condition)
Equipment: GPC-8020 manufactured by Tosoh Corporation
Detector: RI-8020 manufactured by Tosoh Corporation
Column: Gelpack GLA160S + GLA150S manufactured by Hitachi Kasei Co., Ltd.
Sample concentration: 120 mg / 3 mL
Solvent: Tetrahydrofuran Injection amount: 60 μL
Pressure: 2.94 x 106 Pa (30 kgf / cm ² )
Flow rate: 1.00 mL / min

Further, the content of (a) the film forming material is independently contained in the conductive adhesive layer 13 and the insulating adhesive layer 14, respectively, as the component (a), the component (b), the component (c) and the component (d). It is preferably 5% by mass to 80% by mass, and more preferably 15% by mass to 70% by mass based on the total amount of. When this content is 5% by mass or more, good film formability can be easily obtained, and when it is 80% by mass or less, the adhesive composition for forming the adhesive layer has good fluidity. It tends to show.

As the epoxy compound of the component (b), one of a bisphenol type epoxy resin derived from epichlorohydrin and at least one selected from the group consisting of bisphenol A, bisphenol F, bisphenol AD and the like, epichlorohydrin and phenol novolac and cresol novolac. Alternatively, it has an epoxy novolak resin derived from both, a naphthalene-based epoxy resin having a skeleton containing a naphthalene ring, and two or more glycidyl groups in one molecule such as glycidylamine, glycidyl ether, biphenyl, and alicyclic. Various epoxy compounds and the like can be used alone or in combination of two or more. From the viewpoint of preventing electromigration, it is preferable to use a high-purity epoxy resin in which impurity ions (Na ⁺ , Cl ^−, etc.), hydrolyzable chlorine, etc. are reduced to 300 ppm or less.

Among the above epoxy resins, a bifunctional or higher polyfunctional epoxy resin is preferable in that good curability can be obtained. Among these, bisphenol type epoxy and trifunctional or higher functional epoxy resin are particularly preferable from the viewpoint of controlling the molecular weight and the cured physical properties of the obtained cured product.

Further, the oxetane compound as the component (b) preferably contains an oxetane compound having 1 to 4 oxetane rings in the molecule.

Examples of the oxetane compound having one oxetane ring include compounds represented by the following general formula (5).

In the general formula (5), R ⁵ is a hydrogen atom, a methyl group, an ethyl group, a propyl group or butyl alkyl group having 1 to 6 carbon atoms such as a group, the number 1-6 fluoroalkyl group having a carbon, allyl , Aryl group, frill group or thienyl group. R ⁶ is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, a 1-propenyl group, a 2-propenyl group, a 2-methyl-1-propenyl group, and a 2-methyl-. An alkenyl group having 2 to 6 carbon atoms such as a 2-propenyl group, a 1-butenyl group, a 2-butenyl group or a 3-butenyl group, a phenyl group, a benzyl group, a fluorobenzyl group, a methoxybenzyl group or a phenoxyethyl group. Alkylcarbonyl group having 2 to 6 carbon atoms such as a group having an aromatic ring, ethylcarbonyl group, propylcarbonyl group or butylcarbonyl group, ethoxycarbonyl group, propoxycarbonyl group or butoxycarbonyl group having 2 to 6 carbon atoms It is an N-alkylcarbamoyl group having 2 to 6 carbon atoms such as an alkoxycarbonyl group, an ethylcarbamoyl group, a propylcarbamoyl group, a butylcarbamoyl group or a pentylcarbamoyl group.

Examples of the oxetane compound having two oxetane rings include a compound represented by the following general formula (6).

In the general formula (6), R ⁵ is the same group as that in the above general formula (5). R ⁷ is, for example, a linear or branched alkylene group such as an ethylene group, a propylene group or a butylene group, and a linear or branched poly (alkyleneoxy) such as a poly (ethyleneoxy) group or a poly (propyleneoxy) group. ) Group, linear or branched unsaturated hydrocarbon group such as propenylene group, methylpropenylene group or butenylene group, carbonyl group, alkylene group containing carbonyl group, alkylene group containing carboxyl group or alkylene group containing carbamoyl group. And so on.

Further, R ⁷ may be a multivalent group selected from the groups represented by the following general formulas (7) to (19). Among these, the group represented by the formula (14) is preferable from the viewpoint of curability and suppression of peeling.

In the general formula (7), R ⁸ represents a hydrogen atom, a methyl group, an ethyl group, a propyl group or a butyl group alkyl group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, and a propoxy group or a butoxy group It is an alkoxy group having 1 to 4 carbon atoms, a halogen atom such as a chlorine atom or a bromine atom, a nitro group, a cyano group, a mercapto group, a lower alkylcarboxyl group, a carboxyl group, or a carbamoyl group.

In the general formula (8), R ⁹ is an oxygen atom, a sulfur atom, a methylene group, an amino group, a sulfonyl group, a bis (trifluoromethyl) methylene group, or a dimethylmethylene group.

In the general formula (9), R ¹⁰ is an alkyl group having 1 to 4 carbon atoms such as a hydrogen atom, a methyl group, an ethyl group, a propyl group or a butyl group, a methoxy group, an ethoxy group, a propoxy group or a butoxy group. It is an alkoxy group having 1 to 4 carbon atoms, a halogen atom such as a chlorine atom or a bromine atom, a nitro group, a cyano group, a mercapto group, a lower alkylcarboxyl group, a carboxyl group, or a carbamoyl group.

In the general formula (10), R ¹¹ is an oxygen atom, a sulfur atom, a methylene group, an amino group, a sulfonyl group, a bis (trifluoromethyl) methylene group, a dimethylmethylene group, a phenylmethylmethylene group, or a biphenylmethylene group. ..

In the general formula (11) and the general formula (12), R ¹² is an alkyl group having 1 to 4 carbon atoms such as a hydrogen atom, a methyl group, an ethyl group, a propyl group or a butyl group, a methoxy group, an ethoxy group and a propoxy. It is an alkoxy group having 1 to 4 carbon atoms such as a group or a butoxy group, a halogen atom such as a chlorine atom or a bromine atom, a nitro group, a cyano group, a mercapto group, a lower alkylcarboxyl group, a carboxyl group or a carbamoyl group. Further, in R ¹² , 2 to 4 positions of the naphthalene ring may be substituted.

Preferred examples of the oxetane compound having two oxetane rings other than the above-mentioned compounds include the compound represented by the following general formula (20). In the general formula (20), R ⁵ is the same group as that in the general formula (5).

Examples of the oxetane compound having 3 to 4 oxetane rings include compounds represented by the following general formula (21).

In the general formula (21), R ⁵ is the same group as that in the general formula (5), and m is 3 or 4. The R ¹³ is, for example, a branched alkylene group having 1 to 12 carbon atoms such as a group represented by the following general formula (22), formula (23) and formula (24), and is represented by the following general formula (25). Examples thereof include branched poly (alkyleneoxy) groups such as groups.

一般式（２２）において、Ｒ^１４はメチル基、エチル基又はプロピル基等の低級アルキル基である。

In the general formula (22), R ¹⁴ is a lower alkyl group such as a methyl group, an ethyl group or a propyl group.

一般式（２５）において、ｐは１〜１０の整数である。

In the general formula (25), p is an integer of 1 to 10.

Preferred specific examples of the oxetane compound used in the present invention include the compound represented by the following formula (26).

In addition to the above-mentioned oxetane compounds, examples thereof include oxetane compounds having 1 to 4 oxetane rings having a relatively high molecular weight of about 1,000 to 5,000. Further, as the polymer containing oxetane, a polymer having an oxetane ring in the side chain or the like can also be used in the same manner. In the present invention, one type of oxetane compound may be used alone, or two or more types may be used in combination.

The oxetane equivalent of the oxetane compound is preferably 43 to 1000, more preferably 50 to 800, and particularly preferably 73 to 600. When the oxetane equivalent is less than 43 or more than 1000, the adhesive strength between the electrodes tends to decrease. As these oxetane compounds, ^{it is preferable to use a high-purity product in which impurity ions (Na +} , Cl ^−, etc.) and hydrolyzable chlorine are reduced to 300 ppm or less from the viewpoint of corrosion prevention.

The contents of the epoxy compound and the oxetane compound may be 5 to 50 parts by mass with respect to 100 parts by mass of the total mass of each adhesive layer independently in the conductive adhesive layer 13 and the insulating adhesive layer 14. It is preferably 20 to 40 parts by mass, and more preferably 20 to 40 parts by mass. When the content of the epoxy resin and the oxetane compound is 5 parts by mass or more, there is a tendency that the decrease in the fluidity of the anisotropic conductive film can be suppressed when the circuit members are crimped to each other, and when the content is 50 parts by mass or less, long-term storage is performed. Sometimes there is a tendency to suppress deformation of the anisotropic conductive film. Further, the epoxy compound and the oxetane compound may be used in combination, and two or more kinds of each may be selected and blended.

As the thiol compound of the component (c), it is preferable to use a polythiol compound having two or more thiol groups, for example, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 2 , 3-Butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,10-decandithiol, 1,3-benzenedithiol, 1,4-benzenedithiol, 4, 4'-thiobisbenzenethiol, 4,4'-biphenyldithiol, 1,5-dimercaptonaphthalene, 4,5-bis (mercaptomethyl) -ortho-xylene, 1,3,5-benzenetrithiol, 1, 4-Butandiol bis (thioglycolate), dithioethitritol, 3,6-dioxa-1,8-octanedithiol, 3,7-dithia-1,9-nonandithiol, bis (2-mercaptoethyl) sulfide , Ethaneglycolbis (mercaptoacetate), ethyleneglycolbis (3-mercaptopropionate), ethyleneglycolbis (3-mercaptobutyrate), ethyleneglycolbis (3-mercaptoisobutyrate), butanediolbis (mercaptoacetate) ), Butanediol bis (3-mercaptopropionate), butanediol bis (3-mercaptobutyrate), butanediolbis (3-mercaptoisobutyrate), pentaerythritol tori (mercaptoacetate), pentaerythritol tori (3) -Mercaptopropionate), pentaerythritol tori (3-mercaptobutyrate), pentaerythritol tori (3-mercaptoisobutyrate), pentaerythritol tetrakis (mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), Pentaerythritol tetrakis (3-mercaptobutyrate), pentaerythritol tetrakis (3-mercaptoisobutyrate), trimethylolethane (mercaptoacetate), trimethylolethane (3-mercaptopropionate), trimethylolethane (3-mercapto) Butyrate), Trimethylolethane (3-mercaptoisobutyrate), Trimethylol propanetris (mercaptoacetate), Trimethylol propanetris (3-mercaptopropionate), Trimethylol propanetris (3-meth) Lucaptobutyrate), Trimethylol Propylanthris (3-mercaptoisobutyrate), Dipentaerythritol Hexakis (Mercaptoacetate), Dipentaerythritol Hexakis (3-Mercaptopropionate), Dipentaerythritol Hexakis (3) -Mercaptobutyrate), dipentaerythritol hexakis (3-mercaptoisobutyrate), 1,4-bis (3-mercaptopropyloxy) butane, 1,4-bis (3-mercaptobutylyloxy) butane, 1, , 3,5-Tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, Tris [(3-mercaptopropionyloxy) ethyl] isocia Examples thereof include polythiol compounds having 2 to 5 thiol groups such as nurate and tetraethylene glycol bis (3-mercaptopropionate). Of these, considering reactivity and ease of handling, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) ) -Trione, tris [(3-mercaptopropionyloxy) ethyl] isocyanurate is preferred. These thiol compounds may be used alone or in combination of two or more.

The content of the thiol compound was independently determined in the conductive adhesive layer 13 and the insulating adhesive layer 14, respectively, with respect to (b) the epoxy compound or the oxetane compound, as thiol equivalent (SH equivalent): epoxy equivalent (or oxetane equivalent). ) = 2: 8 to 8: 2, and more preferably a ratio of 3: 7 to 7: 3. When this ratio is in the range of 2: 8 to 8: 2, it is possible to prevent a large amount of unreacted thiol group and epoxy group (or oxetane group) from remaining in the cured product, and the mechanical properties of the cured product. There is a tendency to suppress the decrease in epoxide.

(D) The curing agent that generates a base by light, which is a component, contains a carboxylate represented by the following general formula (1).

一般式（１）中、ＲはＣＨ_３又はＨを示し、Ｘはアミジン類、グアニジン類、又はホスファゼン誘導体から選ばれる塩基類を示す。

In the general formula (1), R represents CH ₃ or H, and X represents a base selected from amidines, guanidines, or phosphazene derivatives.

一般式（２７）中のＲはＣＨ_３又はＨを示す。本実施形態で用いるカルボン酸の例としては、式（２７）の化合物のＲがＣＨ_３である、２−（９−オキソキサンテン−２−イル）プロピオン酸を好適に用いることができる。この化合物は、光照射によって脱炭酸を引き起こすカルボン酸の中で高い光脱炭酸効率を有しており、３６５ｎｍにおいても波長吸収領域を有している。よって、カルボン酸として、２−（９−オキソキサンテン−２−イル）プロピオン酸を用いることで、極めて高効率に塩基を発生させることができる。 The carboxylic acid salt represented by the general formula (1) is composed of a carboxylic acid decarbonated by light irradiation represented by the following general formula (27) and a base consisting of any of amidines, guanidines, and phosphazene derivatives. It is a compound composed of a carboxylate salt.

R in the general formula (27) represents CH ₃ or H. As an example of the carboxylic acid used in this embodiment, 2- (9-oxoxanthene-2-yl) propionic acid in which R of the compound of the formula (27) is CH _{3 can be preferably used.} This compound has a high photodecarboxylation efficiency among carboxylic acids that cause decarboxylation by light irradiation, and has a wavelength absorption region even at 365 nm. Therefore, by using 2- (9-oxoxanthene-2-yl) propionic acid as the carboxylic acid, it is possible to generate a base with extremely high efficiency.

As the amidines that can be used as bases, for example, a compound represented by the following formula (2) can be used.

Further, as the guanidines that can be used as the bases, for example, a compound represented by the following formula (3-1) or formula (3-2) can be used.

Further, as a phosphazene derivative that can be used as a base, for example, a compound represented by the following formula (4-1), formula (4-2), formula (4-3), or formula (4-4). Can be used.

These bases have a high acid dissociation constant (pKa), and the compounds represented by the formula (2) are generally 12 to 13, formulas (3-1) to (3-2), and formulas (4-1) to. The compound represented by (4-4) exceeds 13.5, is very basic, and can be expected to have high reactivity.

Therefore, 2- (9-oxoxanthene-2-yl) propionic acid and formulas (2), formulas (3-1) to (3-2), or formulas (4-1) to (4-4) The curing agent consisting of a salt with the indicated base can obtain high reactivity by irradiating with light.

(D) The content of the curing agent that generates a base by light is independently determined by the conductive adhesive layer 13 and the insulating adhesive layer 14, respectively, with (b) an epoxy compound or an oxetane compound and (c) a thiol compound. It is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass in total. When the content of the component (d) is 0.5 parts by mass or more, (b) the epoxy compound or the oxetane compound can be sufficiently reacted, and a good cured product tends to be stably obtained. .. (D) When the content of the component is 30 parts by mass or less, good physical properties of the cured product tend to be obtained. Although high reactivity can be obtained when the content of the component (d) exceeds 30 parts by mass, it is preferably 30 parts by mass or less from the viewpoint of the physical properties of the cured product. In order to achieve both curability and good cured physical properties, the content of the component (d) is more preferably 1 to 30 parts by mass, further preferably 3 to 25 parts by mass, and 5 to 15 parts by mass. Is particularly preferable.

Further, the adhesive layer forming the conductive adhesive layer 13 and the insulating adhesive layer 14 is a basic growth agent, a filler, a softener, an accelerator, an antioxidant, a colorant, a flame retardant, and a thixotropic. It may further contain an agent, a coupling agent, a phenol resin, a melamine resin, isocyanates and the like.

When the adhesive layer contains a filler, further improvement in connection reliability can be expected. The maximum diameter of the filler is preferably less than the particle size of the conductive particles. The content of the filler is 5 volumes in the conductive adhesive layer 13 and the insulating adhesive layer 14, respectively, with respect to a total of 100 parts by volume of the component (a), the component (b) and the component (c). It is preferably a part to 60 parts by volume. If this content exceeds 60 parts by volume, the effect of improving reliability may be saturated, and if it is less than 5 parts by volume, the effect of addition is small.

The anisotropic conductive film may contain conductive particles P. In the anisotropic conductive films 11 and 21, the conductive particles P are contained in the conductive adhesive layer 13.

Examples of the conductive particles P include metal particles such as Au, Ag, Ni, Cu, and solder, carbon, and the like. In order to obtain sufficient storage stability, the surface layer is not transition metals such as Ni and Cu. Au, Ag and platinum group noble metals are preferable, and Au is more preferable. Further, the surface of the transition metal such as Ni may be coated with a noble metal such as Au. Further, non-conductive glass, ceramics, plastics and the like coated with a conductive substance such as the above-mentioned metal can also be used, and in this case as well, those in which the outermost layer is a noble metal are preferable.

If non-conductive plastic or the like coated with a conductive substance or heat-melted metal particles are used as the conductive particles P, these conductive particles are deformed by heating and pressurizing, so that the contact area with the electrode increases at the time of connection. However, it is preferable because it tends to absorb the variation in the thickness of the circuit terminal of the circuit member and improve the connection reliability.

The thickness of the coating layer of the noble metal is preferably 10 nm or more from the viewpoint of obtaining good resistance. On the other hand, when a layer of precious metals is provided on a transition metal such as Ni, free radicals are generated by the redox action caused by the defects of the precious metals layer and the defects of the precious metals layer generated during the mixing and dispersion of the conductive particles P. Since it tends to cause a decrease in storage stability, the thickness of the coating layer is preferably 30 nm or more from the viewpoint of preventing this. The upper limit of the thickness of the coating layer is not particularly limited, but it is preferably 1 μm or less because the obtained effect is saturated.

The content of the conductive particles P is preferably 0.1 to 50 parts by volume with respect to 100 parts by volume of the total of the components (a), (b) and (c), and is used within this range. It is preferable to make appropriate adjustments accordingly. The content is more preferably 0.1 to 40 parts by volume from the viewpoint of preventing short circuits of adjacent circuits due to the excessive presence of conductive particles.

A sensitizer can be added to the adhesive layer of the anisotropic conductive film of the present embodiment in order to expand the photosensitive wavelength region and increase the sensitivity. The sensitizer that can be used is not particularly limited, but for example, benzophenone, p, p'-tetramethyldiaminobenzophenone, p, p'-tetraethylaminobenzophenone, 2-chlorothioxanthone, anthracene, 9-ethoxyanthracene, anthracene. , Pyrene, perylene, phenothiazine, benzyl, aclysine orange, benzoflavin, setoflavin-T, 9,10-diphenylanthracene, 9-fluorenone, acetophenone, phenanthrene, 2-nitrofluorene, 5-nitroacenaften, benzoquinone, 2-chloro -4-Nitroaniline, N-acetyl-p-nitroaniline, p-nitroaniline, N-acetyl-4-nitro-1-naphthylamine, picramid, anthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1, 2-Benz anthraquinone, 3-methyl-1,3-diaza-1,9-benzanthrone, dibenzalacene, 1,2-naphthoquinone, 3,3'-carbonyl-bis (5,7-dimethoxycarbonylcoumarin) Alternatively, coronen and the like can be mentioned. One of these sensitizers may be used alone, or two or more of them may be used in combination.

A silane coupling agent can be added to the adhesive layer of the anisotropic conductive film of the present embodiment from the viewpoint of improving the adhesiveness of the circuit board. Examples of the silane coupling agent include a silane coupling agent containing a ketimine group, a vinyl group, an acrylic group, an amino group, an epoxy group and an isocyanate group. These can be used alone or in combination of two or more. When the adhesive layer contains a silane coupling agent, the content thereof is the addition effect and the ability to form the adhesive layer with respect to a total of 100 parts by mass of the component (a), the component (b) and the component (c). From the viewpoint of compatibility between the above, 0.5 to 30 parts by mass is preferable, and 1 to 20 parts by mass is more preferable.

In the anisotropic conductive film, the thickness of the conductive adhesive layer 13 is preferably 2 μm to 10 μm, preferably 3 μm to 8 μm, from the viewpoint of obtaining good connection reliability due to the particles captured between the facing circuits. Is more preferable.

Further, the thickness of the insulating adhesive layer 14 can be appropriately set. The total thickness of the conductive adhesive layer 13 and the insulating adhesive layer 14 is preferably, for example, 5 μm to 30 μm. Further, usually, the total thickness of the conductive adhesive layer 13 and the insulating adhesive layer 14 and the mounting surface 5a of the first circuit member 2 in the connection structure 1 to the mounting surface 7a of the second circuit member 3 The difference from the distance (value obtained by subtracting the distance from the total thickness) is preferably 0 μm to 10 μm. From the viewpoint of filling the space between the first and second circuit members 2 and 3 with the cured product 4 of the anisotropic conductive film, the above difference is preferably 0.5 μm to 8.0 μm, and 1.0 μm to 1.0 μm. It is more preferably 5.0 μm.

[Manufacturing method of connection structure]
Next, an embodiment of the method for manufacturing the connection structure of the present invention will be described. In the following description, a case where the connection structure 1 shown in FIG. 1 is manufactured by using the anisotropic conductive film 11 shown in FIG. 2 will be described as an example.

FIG. 4 is a schematic cross-sectional view showing a manufacturing process of the connection structure shown in FIG. In forming the connection structure 1, first, the release film 12 is peeled from the anisotropic conductive film 11, and the anisotropic conductive film 11 is secondly formed so that the conductive adhesive layer 13 side faces the mounting surface 7a. It is laminated on the circuit member 3 of. Next, as shown in FIG. 5, the first circuit member 2 is arranged on the second circuit member 3 on which the anisotropic conductive film 11 is laminated so that the bump electrode 6 and the circuit electrode 8 face each other. do. Then, while heating the anisotropic conductive film 11, the first circuit member 2 and the second circuit member 3 are pressed in the thickness direction, and the ultraviolet rays are further applied to the back surface of the second circuit member 3 (second circuit member). Irradiation is performed from the surface opposite to the anisotropic conductive film 11 of 3.

As a result, the adhesive component of the anisotropic conductive film 11 flows, the distance between the bump electrode 6 and the circuit electrode 8 is shortened, and the conductive particles P are in mesh with each other, and the conductive adhesive layer 13 and the insulating adhesive are engaged. The layer 14 is cured. By curing the conductive adhesive layer 13 and the insulating adhesive layer 14, the bump electrode 6 and the circuit electrode 8 are electrically connected, and the adjacent bump electrodes 6, 6 and the adjacent circuit electrodes 8 and 8 are connected to each other. The cured product 4 of the anisotropic conductive film is formed in a state of being electrically insulated, and the connection structure 1 shown in FIG. 1 is obtained. In the obtained connection structure 1, the cured product 4 of the anisotropic conductive film sufficiently prevents the distance between the bump electrode 6 and the circuit electrode 8 from changing with time, and the long-term reliability of the electrical characteristics is sufficiently prevented. Can also be secured.

The heating temperature of the anisotropic conductive film 11 is preferably higher than the temperature at which the polymerization of the epoxy compound, the oxetane compound, and the thiol compound proceeds due to the base generated by the ultraviolet rays. This heating temperature is, for example, 30 ° C to 200 ° C, preferably 40 ° C to 180 ° C. The heating time is, for example, 0.1 to 30 seconds, preferably 1 to 20 seconds. If the heating temperature is less than 30 ° C, the curing rate slows down, and if it exceeds 180 ° C, unwanted side reactions tend to proceed. Further, if the heating time is less than 0.1 seconds, the curing reaction does not proceed sufficiently, and if it exceeds 30 seconds, the productivity of the cured product decreases, and further unwanted side reactions are likely to proceed.

Irradiation of ultraviolet rays may be started at the same time as pressurizing the first circuit member 2 and the second circuit member 3 in the thickness direction, but in terms of flowing the adhesive component of the anisotropic conductive film 11. It is preferable that the irradiation start time is later than the heating and pressurizing start time and is delayed by 0.1 to 4 seconds from the heating and pressurizing start time. If the irradiation start time is delayed by 4 seconds or more, the resin may flow excessively and a gap may be formed between the first circuit member 2 and the second circuit member 3, resulting in a decrease in adhesiveness and connection reliability. May cause a decrease in. Further, the irradiation start time is preferably delayed by 1 to 3 seconds from the heating and pressurizing start time, and in this case, the meshing state of the conductive particles is good. Further, the ultraviolet irradiation amount is not particularly limited as long as it is an irradiation amount in which a base is sufficiently generated from a curing agent that generates a base by (d) light, and it varies depending on the type and content of the curing agent. Although it cannot be said, it is usually 50 to 2000 mJ / cm ² , preferably 100 to 1000 mJ / cm ² .

Next, another embodiment of the method for manufacturing the connection structure of the present invention will be described. When the connection structure 1 shown in FIG. 1 is formed by the manufacturing method of the present embodiment, first, as shown in FIG. 4, the release film 12 is peeled from the anisotropic conductive film 11 and the conductive adhesive layer 13 is formed. The anisotropic conductive film 11 is laminated on the second circuit member 3 so that the side faces the mounting surface 7a, and then is irradiated with ultraviolet rays. By irradiation with ultraviolet rays, a base is generated from the curing agent that generates a base by the light (d) in the anisotropic conductive film 11, but since heating is not performed, in this state, the anisotropic conductive film 11 Curing does not proceed. Next, as shown in FIG. 5, the first circuit member 2 is arranged on the second circuit member 3 on which the anisotropic conductive film 11 is laminated so that the bump electrode 6 and the circuit electrode 8 face each other. do. Then, while heating the anisotropic conductive film 11, the first circuit member 2 and the second circuit member 3 are pressed in the thickness direction.

As a result, the adhesive component of the anisotropic conductive film 11 flows, the distance between the bump electrode 6 and the circuit electrode 8 is shortened, and the conductive particles P are in mesh with each other, and the conductive adhesive layer 13 and the insulating adhesive are engaged. The layer 14 is cured. By curing the conductive adhesive layer 13 and the insulating adhesive layer 14, the bump electrode 6 and the circuit electrode 8 are electrically connected, and the adjacent bump electrodes 6, 6 and the adjacent circuit electrodes 8 and 8 are connected to each other. The cured product 4 of the anisotropic conductive film is formed in a state of being electrically insulated, and the connection structure 1 shown in FIG. 1 is obtained. In the obtained connection structure 1, the cured product 4 of the anisotropic conductive film sufficiently prevents the distance between the bump electrode 6 and the circuit electrode 8 from changing with time, and the long-term reliability of the electrical characteristics is sufficiently prevented. Can also be secured.

The heating temperature of the anisotropic conductive film 11 is preferably higher than the temperature at which the polymerization of the epoxy compound, the oxetane compound, and the thiol compound proceeds due to the base generated by the ultraviolet rays. This heating temperature is, for example, 30 ° C to 200 ° C, preferably 40 ° C to 180 ° C. The heating time is, for example, 0.1 to 30 seconds, preferably 1 to 20 seconds. If the heating temperature is less than 30 ° C, the curing rate slows down, and if it exceeds 180 ° C, unwanted side reactions tend to proceed. Further, if the heating time is less than 0.1 seconds, the curing reaction does not proceed sufficiently, and if it exceeds 30 seconds, the productivity of the cured product decreases, and further unwanted side reactions are likely to proceed.

Further, the ultraviolet irradiation amount is not particularly limited as long as it is an irradiation amount in which a base is sufficiently generated from a curing agent that generates a base by (d) light, and it varies depending on the type and content of the curing agent. Although it cannot be said, it is usually 50 to 2000 mJ / cm ² , preferably 100 to 1000 mJ / cm ² .

[Manufacturing method of anisotropic conductive film]
The anisotropic conductive film can be produced by applying an adhesive paste, which is a material for forming the conductive adhesive layer 13, on the release film 12 and drying the adhesive paste.

The viscosity of the adhesive paste can be varied depending on the application and coating method, but is usually preferably 10 mPa · s to 10000 mPa · s. From the viewpoint of suppressing the separation of the compound in the adhesive paste and improving the compatibility, it is more preferably 50 mPa · s to 5000 mPa · s. Further, in order to improve the appearance of the anisotropic conductive film, it is preferably 100 mPa · s to 3000 mPa · s.

As a method for applying the adhesive paste, a known method can be used. For example, spin coating method, roller coating method, bar coating method, dip coating method, micro gravure coating method, curtain coating method, die coating method, spray coating method, doctor coating method, kneader coating method, flow coating method, screen printing method, cast. The law etc. can be mentioned. The bar coating method, the die coating method, the microgravure coating method and the like are suitable for producing an anisotropic conductive film, and the die coating method is particularly suitable from the viewpoint of the accuracy of the film thickness.

The drying temperature of the adhesive paste is preferably, for example, 20 ° C to 100 ° C. At temperatures below 20 ° C, drying may be inadequate, and at temperatures above 100 ° C, the formulations in the anisotropic conductive film may cause unexpected reactions.

After the formation of the conductive adhesive layer 13, a separately prepared insulating adhesive layer 14 may be laminated on the conductive adhesive layer 13 to form a two-layer anisotropic conductive film. For example, a hot roll laminator can be used for laminating the insulating adhesive layer 14. Further, the present invention is not limited to laminating, and an adhesive paste used as a material for the insulating adhesive layer 14 may be applied and dried on the conductive adhesive layer 13.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

For example, in the anisotropic conductive film 11 shown in FIG. 2, the arrangement of the conductive adhesive layer 13 and the insulating adhesive layer 14 may be reversed. That is, the insulating adhesive layer 14 and the conductive adhesive layer 13 may be laminated in this order on the release film 12.

Further, in the anisotropic conductive film 11 shown in FIG. 2, only one of the conductive adhesive layer 13 and the insulating adhesive layer 14 is the component (a) and the component (b) described above. , (C) component and (d) component may be a layer.

Further, the anisotropic conductive film may be composed of the release film 12 and the insulating adhesive layer 14 formed on the release film 12.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<Synthesis of a curing agent (photobase generator) that generates a base by light>
(Synthesis Example 1)
2- (9-oxoxanthene-2-yl) propionic acid (manufactured by Tokyo Kasei Co., Ltd.) 5.36 g (20.0 mmol) in a tetrahydrofuran solution (20 mL) in 1,8-diazabicyclo [5,4,0] undeca- A solution of 3.04 g (20.0 mmol) of 7-ene (manufactured by Tokyo Kasei Co., Ltd.) in tetrahydrofuran (20 mL) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Then, the solvent was distilled off under reduced pressure, and impurities were extracted and removed using diethyl ether as a poor solvent and tetrahydrofuran as a good solvent to remove 2- (9-oxoxanthene-2-yl) propionic acid 1,8-diazabicyclo [5]. , 4,0] Undec-7-ene salt (photobase generator 1) was obtained in an amount of 4.38 g (yield 52%).

(Synthesis Example 2)
2- (9-oxoxanthene-2-yl) propionic acid (manufactured by Tokyo Kasei Co., Ltd.) 5.36 g (20.0 mmol) in a tetrahydrofuran solution (20 mL) in 1,5,7-triazabicyclo [4,4 0] 2.78 g (20.0 mmol) of a solution of deca-5-ene (manufactured by Tokyo Kasei Co., Ltd.) in tetrahydrofuran (20 mL) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Then, the solvent was distilled off under reduced pressure, and impurities were extracted and removed using diethyl ether as a poor solvent and tetrahydrofuran as a good solvent to remove 2- (9-oxoxanthen-2-yl) propionic acid 1,5,7-tria. 5.06 g (yield 62%) of Zabicyclo [4,4,0] deca-5-ene salt (photobase generator 2) was obtained.

(Synthesis Example 3)
2- (9-oxoxanthene-2-yl) propionic acid (manufactured by Tokyo Kasei Co., Ltd.) 5.36 g (20.0 mmol) in a tetrahydrofuran solution (20 mL) in 7-methyl-1,5,7-triazabicyclo [ 4,4,0] Deca-5-ene (manufactured by Tokyo Kasei Co., Ltd.) 3.06 g (20.0 mmol) in a tetrahydrofuran solution (20 mL) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Then, the solvent was distilled off under reduced pressure, and the impurities were extracted and removed using diethyl ether as the poor solvent and tetrahydrofuran as the good solvent to remove the impurities, and 7-methyl-1,5 2- (9-oxoxanthen-2-yl) propionic acid. , 7-Triazabicyclo [4,4,0] deca-5-ene salt (photobase generator 3) was obtained in an amount of 4.12 g (yield 49%).

(Synthesis Example 4)
2- (9-oxoxanthene-2-yl) propionic acid (manufactured by Tokyo Kasei Co., Ltd.) 5.36 g (20.0 mmol) in a tetrahydrofuran solution (10 mL) in tert-butylimino-tris (dimethylamino) phosphorane (SIGMA-ALDRICH) (Manufactured by) 2.34 g (10.0 mmol) of a tetrahydrofuran solution (10 mL) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Then, the solvent was distilled off under reduced pressure, and impurities were extracted and removed using diethyl ether as a poor solvent and tetrahydrofuran as a good solvent to remove impurities, and tert-butylimino-tris (dimethyl) 2- (9-oxoxanthene-2-yl) propionate. 1.90 g (38% yield) of an amino) phosphoran salt (photobase generator 4) was obtained.

(Synthesis Example 5)
2- (3-Benzoylphenyl) propionic acid (manufactured by Tokyo Kasei Co., Ltd.) 5.08 g (20.0 mmol) in a tetrahydrofuran solution (20 mL) in 1,5,7-triazabicyclo [4,4,0] deca- 2.78 g (20.0 mmol) of 5-ene (manufactured by Tokyo Kasei Co., Ltd.) in a tetrahydrofuran solution (20 mL) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Then, the solvent was distilled off under reduced pressure, and impurities were extracted and removed using diethyl ether as a poor solvent and tetrahydrofuran as a good solvent to remove 2- (3-benzoylphenyl) propionic acid 1,5,7-triazabicyclo [4]. , 4,0] Deca-5-ene salt (photobase generator 5) was obtained in an amount of 4.56 g (yield 58%).

<Manufacturing an anisotropic conductive film>
(Example 1)
Phenoxy resin (product name: YP-70, manufactured by Nippon Steel & Sumitomo Metal Corporation) as a film forming material, bisphenol A type epoxy resin (product name: 828, manufactured by Mitsubishi Chemical Corporation) as an epoxy compound, and penta as a thiol compound. Erislitol tetrakis (3-mercaptobutyrate) (product name: Karenz MT PE1, manufactured by Showa Denko Co., Ltd.), photobase generator 1 synthesized in Synthesis Example 1 as a photobase generator, 3-methacryloxy as a silane coupling agent Epoxytrimethoxysilane (product name: KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) was used. As conductive particles, 35 parts by volume of Ni-plated polystyrene particles (average particle size 3 μm) were used. An adhesive composition was prepared by blending each component so as to have the mixing ratio shown in Table 1. The adhesive composition is applied to a PET film having a thickness of 50 μm on one side surface-treated using a coating device, and dried with hot air at 70 ° C. for 5 minutes to increase the thickness of the adhesive layer (conductive adhesive layer). A 20 μm anisotropic conductive film was obtained.

(Example 2)
As a thiol compound, 1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (product name: Karenz MT NR1) , Showa Denko), an anisotropic conductive film was obtained in the same manner as in Example 1.

(Example 3)
An anisotropic conductive film was obtained in the same manner as in Example 1 except that a polyfunctional epoxy resin (product name: 1032H60, manufactured by Mitsubishi Chemical Corporation) was used as the epoxy compound.

(Example 4)
As a thiol compound, 1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (product name: Karenz MT NR1) , Showa Denko), an anisotropic conductive film was obtained in the same manner as in Example 3.

(Example 5)
An anisotropic conductive film was obtained in the same manner as in Example 2 except that biphenylene bis oxetane (product name: OXBP, manufactured by Ube Industries, Ltd.) was used as the oxetane compound.

(Example 6)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the photobase generator 2 synthesized in Synthesis Example 2 was used as the photobase generator.

(Example 7)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the photobase generator 3 synthesized in Synthesis Example 3 was used as the photobase generator.

(Example 8)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the photobase generator 4 synthesized in Synthesis Example 4 was used as the photobase generator.

(Examples 9 to 12)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the epoxy compound was blended in the amounts shown in Table 1.

(Comparative Example 1)
Bisphenol A type epoxy resin (product name: 828, manufactured by Mitsubishi Chemical Corporation) was used as the epoxy compound in an amount of 50 parts by mass, and the thiol compound was not blended. I got a film.

(Comparative Example 2)
As the thiol compound, 50 parts by mass of pentaerythritol tetrakis (3-mercaptobutyrate) (product name: Karenz MT PE1, manufactured by Showa Denko) was used, and the same as in Example 1 except that the epoxy compound was not blended. To obtain an anisotropic conductive film.

(Comparative Example 3)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the photobase generator 5 synthesized in Synthesis Example 5 was used as the photobase generator.

(Comparative Example 4)
4-Methylphenyl-4- (1-methylethyl) phenyliodonium tetrakis (pentafluorophenyl) borate (product name; PI-2074, manufactured by Rhodia) was used as the photoacid generator instead of the photobase generator. Except for this, an anisotropic conductive film was obtained in the same manner as in Example 1.

In Table 1, each numerical value represents a mass part except for conductive particles. The numerical value of the conductive particles represents a volume part with respect to a total of 100 parts by volume of the film forming material, the epoxy compound or the oxetane compound, and the thiol compound.

(Evaluation of storage stability)
The anisotropic conductive films of Examples 1 to 12 and Comparative Examples 1 to 4 were left in a constant temperature device at 40 ° C. for 5 days. After standing, the infrared absorption spectrum of each anisotropic conductive film was measured, and the conversion rate of the cyclic ether of the epoxy compound (or oxetane compound) was calculated. The results are shown in Tables 2 to 4 in which the conversion rate of the cyclic ether is less than 5% as ⊚, 5% or more and less than 10% as ◯, and 10% or more as x.

(Manufacturing of connection structure (manufacturing method A))
As the first circuit member, an IC chip having a straight array structure in which bump electrodes are arranged in a row (outer diameter 2 mm × 20 mm, thickness 0.55 mm, bump electrode size 100 μm × 30 μm, bump electrode distance 8 μm, bump electrode thickness). 15 μm) was prepared. Further, as the second circuit member, an ITO wiring pattern (pattern width 21 μm, space between electrodes 17 μm) formed on the surface of a glass substrate (Corning: # 1737, 38 mm × 28 mm, thickness 0.3 mm) is formed. Got ready.

For the connection between the IC chip and the glass substrate, a thermocompression bonding device composed of a quartz stage (150 mm × 150 mm) and a tool (3 mm × 20 mm) made of a ceramic heater and an LED light source generating ultraviolet rays having a wavelength of 365 nm was used. First, the surface of the anisotropic conductive film (2.5 mm × 25 mm) according to Examples 1 to 12 and Comparative Examples 1 to 4 on the conductive adhesive layer side was placed on a glass substrate at 80 ° C. and 0.98 MPa (10 kgf / cm). ^It was attached by heating and pressurizing for 2 seconds under the condition of 2).

Next, the release film on the conductive adhesive layer of the anisotropic conductive film is peeled off, the bump electrode of the IC chip and the circuit electrode of the glass substrate are aligned, and then the measured maximum of the anisotropic conductive film is performed. Heat, pressurize, and irradiate the glass stage with ultraviolet rays for 5 seconds under the conditions of an ultimate temperature of 80 ° C., an ultraviolet intensity of 200 mW / cm ² , and an area conversion pressure of 70 MPa at the bump electrode, and the conductive adhesive layer is formed into an IC chip. I pasted it on. Here, the ultraviolet irradiation was started 2 seconds after the heating and pressurizing start time and was performed for 3 seconds.

(Manufacturing of connection structure (manufacturing method B))
As the first circuit member, an IC chip having a straight array structure in which bump electrodes are arranged in a row (outer diameter 2 mm × 20 mm, thickness 0.55 mm, bump electrode size 100 μm × 30 μm, bump electrode distance 8 μm, bump electrode thickness). 15 μm) was prepared. Further, as the second circuit member, an aluminum wiring pattern (pattern width 21 μm, space between electrodes 17 μm) formed on the surface of a glass substrate (Corning: # 1737, 38 mm × 28 mm, thickness 0.3 mm) is formed. Got ready.

For the connection between the IC chip and the glass substrate, a thermocompression bonding device composed of a quartz stage (150 mm × 150 mm) and a tool (3 mm × 20 mm) made of a ceramic heater and an LED light source generating ultraviolet rays having a wavelength of 365 nm was used. First, the surface of the anisotropic conductive film (2.5 mm × 25 mm) according to Examples 1 to 12 and Comparative Examples 1 to 4 on the conductive adhesive layer side was placed on a glass substrate at 80 ° C. and 0.98 MPa (10 kgf / cm). ^It was attached by heating and pressurizing for 2 seconds under the condition of 2).

Next, the release film on the conductive adhesive layer of the anisotropic conductive film is peeled off, and ^{after irradiating an ultraviolet ray of 300 mJ / cm 2} from the upper surface of the anisotropic conductive film, the bump electrode of the IC chip and the circuit of the glass substrate are used. The alignment with the electrode was performed. Then, the insulating adhesive layer was attached to the IC chip by heating and pressurizing for 5 seconds under the conditions of the measured maximum temperature of the anisotropic conductive film of 80 ° C. and the area conversion pressure of 70 MPa at the bump electrode.

(Manufacturing of connection structure (manufacturing method C))
As the first circuit member, an IC chip having a straight array structure in which bump electrodes are arranged in a row (outer diameter 2 mm × 20 mm, thickness 0.55 mm, bump electrode size 100 μm × 30 μm, bump electrode distance 8 μm, bump electrode thickness). 15 μm) was prepared. Further, as a second circuit member, a polyimide film (Capton 50EN manufactured by Toray DuPont) is attached on a _{film substrate and treated with a SiO 2} oxide film (38 mm × 28 mm, substrate thickness 0.125 mm). ), An aluminum wiring pattern (pattern width 21 μm, space between electrodes 17 μm) was prepared.

For the connection between the IC chip and the film substrate, a thermocompression bonding device composed of a quartz stage (150 mm × 150 mm) and a tool (3 mm × 20 mm) made of a ceramic heater and an LED light source generating ultraviolet rays having a wavelength of 365 nm was used. First, the surface of the anisotropic conductive film (2.5 mm × 25 mm) according to Examples 1 to 12 and Comparative Examples 1 to 4 on the conductive adhesive layer side was placed on a glass substrate at 80 ° C. and 0.98 MPa (10 kgf / cm). ^It was attached by heating and pressurizing for 2 seconds under the condition of 2).

Next, the release film on the conductive adhesive layer of the anisotropic conductive film is peeled off, and ^{after irradiating an ultraviolet ray of 300 mJ / cm 2} from the upper surface of the anisotropic conductive film, the bump electrode of the IC chip and the circuit of the glass substrate are used. The alignment with the electrode was performed. Then, the insulating adhesive layer was attached to the IC chip by heating and pressurizing for 5 seconds under the conditions of the measured maximum temperature of the anisotropic conductive film of 80 ° C. and the area conversion pressure of 70 MPa at the bump electrode.

(Evaluation of connection resistance)
In the connection structures obtained by using the anisotropic conductive films of Examples 1 to 12 and Comparative Examples 1 to 4, the resistance value between the bump electrode and the circuit electrode was evaluated. The resistance value was evaluated by the four-terminal measurement method, and the average value of the measurements at 14 points was used. The poor connection was marked as x. In addition, the resistance value (maximum value among 14 terminals measured) after the high temperature and high humidity test in which a load was applied for 500 hours under the conditions of 85 ° C. and 85% RH was also measured. The results are shown in Tables 2-4.

(Measurement of adhesive strength)
A die shear strength test was carried out on the connection structure produced by the above-mentioned production method A using the anisotropic conductive films of Examples 1 to 12 and Comparative Examples 1 to 4. The poor connection was marked as x. The results are shown in Tables 2-4. The die-share strength was measured using a bond tester Dage-Series-4000 manufactured by Dage and a load cell DS100.

As shown in Tables 2 to 4, the anisotropic conductive films obtained in Examples 1 to 12 achieved both low-temperature curability and storage stability, and obtained good adhesive strength and connection reliability.

On the other hand, as shown in Comparative Examples 1 and 2, when the epoxy compound or the thiol compound was not blended, the first circuit member and the second circuit member could not be connected.

Further, as shown in Comparative Example 3, when the chemical structures of the photobase generators were different, the first circuit member and the second circuit member could not be connected.

Further, as shown in Comparative Example 4, when an acid generator is used, the connection structure can be produced when ultraviolet irradiation and heating / pressurization are simultaneously performed in the production of the connection structure (production method A). However, the adhesive strength was low and the resistance value increased after the moisture resistance test. The connection structure produced by heating and pressurizing after irradiation with ultraviolet rays (production methods B and C) could not connect the first circuit member and the second circuit member. Furthermore, the storage stability deteriorated.

1 ... connection structure, 2 ... first circuit member, 3 ... second circuit member, 6 ... bump electrode, 8 ... circuit electrode, 11 and 21 ... anisotropic conductive film, 12 ... release film, 13 ... conductive Sexual adhesive layer, 14 ... Insulating adhesive layer, P ... Conductive particles.

Claims (10)

An anisotropic conductive film interposed between the circuit electrodes facing each other and used to pressurize the circuit electrodes and electrically connect the electrodes in the pressurizing direction.
(A) Film forming material and
(B) With an epoxy compound or an oxetane compound,
(C) Thiol compound and
(D) A curing agent that generates a base by light,
Equipped with an adhesive layer containing
(D) An anisotropic conductive film in which the curing agent that generates a base by light contains a carboxylic acid salt represented by the following general formula (1).

[In the general formula (1), R represents CH ₃ or H, and X represents a base selected from amidines, guanidines, or phosphazene derivatives. ] The anisotropic conductive film according to claim 1, wherein the amidines are compounds represented by the following formula (2).

The anisotropic conductive film according to claim 1 or 2, wherein the guanidines are compounds represented by the following formula (3-1) or formula (3-2).

Any one of claims 1 to 3, wherein the phosphazene derivative is a compound represented by the following formula (4-1), formula (4-2), formula (4-3), or formula (4-4). The anisotropic conductive film described in the section.

The anisotropic conductive film according to any one of claims 1 to 4, wherein the (c) thiol compound is a polythiol compound having three or more thiol groups. The content of the curing agent that generates a base by (d) light in the adhesive layer is 0.5 to 30 with respect to 100 parts by mass of the total of (b) an epoxy compound or an oxetane compound and (c) a thiol compound. The anisotropic conductive film according to any one of claims 1 to 5, which is a mass portion. The adhesive layer contains conductive particles in an amount of 0.1 to 50 parts by volume with respect to a total of 100 parts by volume of the (a) film-forming material, the (b) epoxy compound or oxetane compound, and the (c) thiol compound. The anisotropic conductive film according to any one of claims 1 to 6, which is contained. Using the cured product of the anisotropic conductive film according to any one of claims 1 to 7, a first circuit member provided with a bump electrode and a circuit electrode corresponding to the bump electrode are provided. A connection structure in which a second circuit member is adhered and the bump electrode and the circuit electrode are electrically connected. One of claims 1 to 7 is provided between the main surface of the first circuit member provided with the bump electrode and the main surface of the second circuit member provided with the circuit electrode corresponding to the bump electrode. The anisotropic conductive film described in the above is arranged, the anisotropic conductive film is heated and pressurized via the first circuit member and the second circuit member, and ultraviolet rays are further emitted from the back surface of the second circuit member. It is irradiated and cured, and the first circuit member and the second circuit member are adhered to each other through the cured product of the anisotropic conductive film, and the bump electrode and the circuit electrode are electrically connected. A method of manufacturing a connection structure. The idiosyncratic conductive film according to any one of claims 1 to 7 is arranged on a second circuit member provided with a circuit electrode, and after irradiating the idiosyncratic conductive film with ultraviolet rays from above, the circuit. A first circuit member provided with a bump electrode corresponding to the electrode is arranged on the idiosyncratic conductive film, and the idiopathic conductive film is heated via the first circuit member and the second circuit member. The first circuit member and the second circuit member are adhered to each other through the cured product of the anisotropic conductive film, and the bump electrode and the circuit electrode are electrically attached to each other. A method of manufacturing a connection structure to be connected.

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