WO2012018123A1

WO2012018123A1 - Anisotropic conductive adhesive film and curing agent

Info

Publication number: WO2012018123A1
Application number: PCT/JP2011/067977
Authority: WO
Inventors: 章大谷; 圭介福本
Original assignee: 旭化成イーマテリアルズ株式会社
Priority date: 2010-08-06
Filing date: 2011-08-05
Publication date: 2012-02-09
Also published as: CN103081236B; CN103081236A; JPWO2012018123A1; KR101456396B1; KR20130041121A; TWI424041B; TW201217481A; JP5373973B2

Abstract

An anisotropic conductive adhesive film which comprises: an organic binder that contains a cationically polymerizable substance; 0.01 to 15 parts by mass of a cation generator represented by general formula (1) per 100 parts by mass of the organic binder; and 0.1 to 20vol% of conductive particles relative to the whole volume of the organic binder. In general formula (1), Q, A, R₄ and Y^- are each as defined in the description.

Description

Anisotropic conductive adhesive film and curing agent

The present invention relates to an anisotropic conductive adhesive film having excellent low-temperature connectivity and excellent peel strength reliability in electrical connection of fine patterns, a method for producing a connection structure using the same, and a curing agent.

An anisotropic conductive adhesive film is a film in which conductive particles are dispersed in an insulating adhesive, in other words, connection between a liquid crystal display and an IC chip or TCP (Tape Carrier Package), FPC (Flexible Printed Circuit) and It is a connection member that is used to easily connect to TCP or FPC and printed wiring board. For example, it is widely used for connection between liquid crystal display of notebook personal computer or mobile phone and control IC. Recently, it is also used for flip chip mounting in which an IC chip is directly mounted on a printed circuit board or a flexible wiring board.

On the other hand, in this field, in recent years, the substrate to be connected has been made thinner and larger, and the demand for connection at a low temperature is increasing in order to alleviate the warp caused by the temperature difference at the time of connection.

An anisotropic conductive adhesive film is mainly made of a thermosetting binder resin from the viewpoint of connection reliability. An epoxy resin is mainly used as the curable resin, and tertiary amines or imidazoles which are anionic polymerization type curing agents are mainly used as the curing agent. Furthermore, it is known to enhance storage stability by macroencapsulating tertiary amines or imidazoles. A cationic curing agent has been proposed as a curing agent that can be cured at a lower temperature than such an anionic polymerization curing agent (Patent Document 1). In addition, a method (Patent Document 2) in which a stabilizer is blended in order to achieve both low-temperature curability and storage stability is known. Furthermore, there has been proposed a method for reducing the influence of impurity ions by using an organic boron compound as a counter ion of a cationic curing agent in a cationic curable resin composition (Patent Documents 3 and 4).

Japanese Patent No. 3907217 Japanese Patent No. 3589422 JP 2008-303167 A JP 2010-132614 A

However, even when these cationic curing agents are used, it is difficult to achieve both low temperature connectivity and peel strength reliability, and there has been a problem that the peel strength tends to decrease when held in a hygroscopic state.

The problem to be solved by the present invention is to provide a highly reliable anisotropic conductive adhesive film that is excellent in low-temperature connectivity and hardly deteriorates in peel strength in electrical connection between opposing wiring circuits. is there. Another object of the present invention is to provide a cationic curing agent having both storage stability and low temperature curability.

As a result of intensive studies to solve the above problems, the present inventors have found that an anisotropic conductive adhesive film having excellent low-temperature connectivity and peel strength reliability can be obtained by the following composition, and make the present invention. It came.

That is, the present invention is as follows.

[1] An organic binder containing a cationically polymerizable substance;
0.01 to 15 parts by mass of the general formula (1) with respect to 100 parts by mass of the organic binder containing the cationic polymerizable substance:

{In Formula (1), Q is a substituted or unsubstituted naphthylmethyl group or a substituted or unsubstituted benzyl group, A is a phenyl group having 1 to 5 substituents, and Q is substituted or unsubstituted When it is a naphthylmethyl group, the sum of Hammett constants of the 1 to 5 substituents is -0.3 to 0, and when Q is a substituted or unsubstituted benzyl group, the Hammett of the 1 to 5 substituents The sum of the constants is 0 to +0.5, R ₄ is an alkyl group having 1 to 6 carbon atoms, and Y ⁻ is a general formula (2):

[In Formula (2), X is respectively independently fluorine, chlorine, or bromine. ] An anion represented by And 0.1 to 20% by volume of conductive particles based on the total volume of the organic binder containing the cationic polymerizable substance;
An anisotropic conductive adhesive film comprising:

[2] In Formula (1), Q is a substituted or unsubstituted naphthylmethyl group, and the sum of Hammett constants of 1 to 5 substituents of A is −0.3 to 0. Anisotropic conductive adhesive film.

[3] In Formula (1), Q is a substituted or unsubstituted benzyl group, and the sum of Hammett constants of 1 to 5 substituents of A is 0 to +0.5. Direction conductive adhesive film.

[4] In the formula (1), A represents the general formula (4):

{In Formula (4), R ₁ is a methyl group, an acetyl group, a phenoxycarbonyl group, a benzyloxycarbonyl group, a benzoyl group or a 9-fluorenylcarbonyl group, and R ₂ and R ₃ are hydrogen, halogen, Or an alkyl group having 1 to 6 carbon atoms. } The anisotropic conductive adhesive film as described in [1] which is group represented by these.

[5] In the formula (4), R ₁ is an acetyl group, a phenoxycarbonyl group, a benzyloxycarbonyl group, or a benzoyl group, and R ₂ and R ₃ are hydrogen or a methyl group, Anisotropic conductive adhesive film.

[6] In the formula (1), Q represents the general formula (3):

{In Formula (3), R ₅ is hydrogen, methyl, methoxy or halogen. } The anisotropic conductive adhesive film according to any one of [1] to [5], which is a substituted or unsubstituted benzyl group, α-naphthylmethyl group, or β-naphthylmethyl group represented by:

[7] The anisotropic conductive adhesive film according to [6], wherein R ₅ in formula (3) is hydrogen or methyl.

[8] The anisotropic conductive adhesive film according to any one of [1] to [7], wherein R ₄ in formula (1) is a methyl group.

[9] The anisotropic conductive adhesive film according to any one of [1] to [8], wherein X in the formula (2) is fluorine.

[10] Any one of [1] to [9], comprising 0.1 to 20 parts by mass of a cation scavenger that reacts with a cation species generated from the cation generator, relative to 100 parts by mass of the cation generator. An anisotropic conductive adhesive film according to item.

[11] The anisotropic conductivity according to [10], wherein the cation scavenger is at least one selected from the group consisting of a thiourea compound, a 4-alkylthiophenol compound, and a 4-hydroxyphenyl-dialkylsulfonium salt. Adhesive film.

[12] The anisotropic conductive adhesive film according to any one of [1] to [11], wherein the cation species generated from the cation generator is at least two or more.

[13] The anisotropic conductive adhesive film according to any one of [1] to [12], wherein the organic binder includes a resorcin type epoxy resin.

[14] A connection structure including a step of heating and pressurizing a pair of electronic circuit boards having a corresponding electrode arrangement through the anisotropic conductive adhesive film according to any one of [1] to [13] Manufacturing method.

[15] A connection structure obtained by the manufacturing method according to [14].

[16] General formula (1):

[In Formula (2), X is respectively independently fluorine, chlorine, or bromine. ] An anion represented by } The cation generator represented by these.

[17] An anisotropic conductive film comprising an organic binder having an epoxy group, a cation generator and conductive particles, wherein the epoxy group reaction rate at 80 ° C. for 10 seconds is less than 10%, and 140 ° C. An anisotropic conductive adhesive film having an epoxy group reaction rate of 80% or more in 10 seconds.

The present invention has an effect that, in electrical connection between opposing circuits, the low-temperature connectivity is excellent and the peel strength is hardly lowered. Moreover, the cationic hardening | curing agent which made the preservability and low-temperature curability compatible can be provided.

Hereinafter, the present invention will be specifically described.

In one embodiment of the present invention, an anisotropic conductive film including an organic binder having an epoxy group, a cation generator, and conductive particles, the epoxy group reaction rate at 80 ° C. for 10 seconds is less than 10%, and An anisotropic conductive adhesive film having an epoxy group reaction rate of 80% or more at 140 ° C. for 10 seconds.

The epoxy group reaction rate at 80 ° C. for 10 seconds is preferably less than 10%, more preferably less than 5%, still more preferably less than 2%. When the epoxy group reaction rate at 80 ° C. for 10 seconds is less than 10%, the storage stability is good and it is difficult to be affected by heat at the time of temporary attachment to a circuit board.

The epoxy group reaction rate at 140 ° C. for 10 seconds is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, and particularly preferably 95% or more. When the epoxy group reaction rate at 140 ° C. for 10 seconds is 80% or more, the connection resistance value and the peel strength are good, and the reliability after connection is also stabilized.

The epoxy group reaction rate can be measured by measuring the epoxy group absorbance ratio by the FT-IR method.

One embodiment of the present invention is an organic binder containing a cationically polymerizable substance; 0.01 to 15 parts by mass of the general formula (1) with respect to 100 parts by mass of the organic binder containing the cationically polymerizable substance:

{In Formula (1), A is a substituted phenyl group, Q is a substituted or unsubstituted naphthylmethyl group or a substituted or unsubstituted benzyl group, and R ₄ is an alkyl group having 1 to 6 carbon atoms. , And Y ⁻ represents the general formula (2):

[In Formula (2), X is respectively independently fluorine, chlorine, or bromine. ] An anion represented by } An anisotropic conductive adhesive film containing 0.1 to 20% by volume of conductive particles with respect to the total volume of the organic binder containing the cationic polymerizable substance.

In the above formula (1), A is a phenyl group having 1 to 5 substituents, and the sum of Hammett constants of the 1 to 5 substituents is −0.3 to 0, Q is preferably a substituted or unsubstituted naphthylmethyl group.

In the above formula (1), A is a phenyl group having 1 to 5 substituents, and the sum of Hammett constants of the 1 to 5 substituents is 0 to +0.5, and Q is preferably a substituted or unsubstituted benzyl group.

Hammett's rule is a 1935 L.S. method for discussing quantitatively the effect of substituents on the reaction or equilibrium of benzene derivatives. P. A rule of thumb proposed by Hammett, which is widely accepted today. The Hammett constant determined by Hammett's rule includes a σp value and a σm value, and these values can be found in many general books. For example, J. et al. A. Dean ed., “Lange's Handbook of Chemistry”, 12th edition, 1979 (McGraw-Hill) or “Chemical Domain”, No. 122, pages 96-103, 1979 (Nankodo), Chem. Rev. 1991, Vol. 91, pages 165-195.

In the present invention, each substituent is limited or explained by Hammett's substituent constant. However, each substituent is limited to only a substituent having a known value that can be found in the above-mentioned book. It is not to be understood that it should be understood that the values also include substituents that would fall within the range when measured according to Hammett's law, even though the values are not described in the literature.

When the Hammett constant is negative, it indicates that the substituent is an electron donating substituent. In the above formula (1), Q is a substituted or unsubstituted naphthylmethyl group, and the phenyl group substituent Hammett When the sum of the constants is −0.3 to 0, it is possible to achieve both good cation generation and appropriate storage stability. The sum of the Hammett constants is more preferably −0.27 to 0, and even more preferably −0.25 to 0.

When the Hammett constant is positive, it indicates that the substituent is an electron-withdrawing substituent. In the above formula (1), Q is a substituted or unsubstituted benzyl group, and the Hammett constant of the substituent of the phenyl group When the sum is 0 to +0.5, it is possible to achieve both good cation generation and appropriate storage stability. The sum of the Hammett constants is preferably 0 to +0.4, more preferably 0 to +0.35, and even more preferably 0 to +0.30.

In the above formula (1), when the substituent represented by Q is a substituted benzyl group, the sum of Hammett constants of these substituents is preferably in the range of −0.2 to +0.2. It is more preferably in the range of −0.15 to +0.15, and further preferably in the range of −0.1 to +0.1. When it is in the range of −0.2 to +0.2, it is preferable because both cation generation and storage stability can be achieved.

For more details, refer to the sum of Hammett constants of the substituents of the phenyl group described in Table 2 described later.

One embodiment of the present invention is an organic binder containing a cationic polymerizable substance; 0.01 to 15 parts by mass of the following general formula (5) with respect to 100 parts by mass of the organic binder component containing the cationic polymerizable substance:

{In Formula (5), R ₁ represents a methyl group, an acetyl group, a phenoxycarbonyl group, a benzyloxycarbonyl group, a benzoyl group, or a 9-fluorenylcarbonyl group, and R ₂ and R ₃ represent hydrogen, halogen, or An alkyl group having 1 to 6 carbon atoms, R ₄ is an alkyl group having 1 to 6 carbon atoms, and Q is the following general formula (3):

(In the formula (3), R ₅ is hydrogen, methyl, methoxy or halogen), an α-naphthylmethyl group or a β-naphthylmethyl group, and Y ⁻ represents the following general formula (2):

[In Formula (2), X is respectively independently fluorine, chlorine, or bromine. ] An anion represented by } An anisotropic conductive adhesive film containing 0.1 to 20% by volume of conductive particles with respect to the total volume of the organic binder containing the cation polymerizable substance.

<Cation generator>
The cation generator used in the present invention may have any structure as long as it is represented by the above general formula (1) or (5), but generates a cation species at 50 ° C. or higher from the viewpoint of storage stability. Is preferred.

The cation species generated by the thermal decomposition of the cation generator of the present invention may have any structure as long as the reactivity with the cationic polymerizable substance is sufficient, but benzyl cation species, α-naphthyl cation species, β -Naphthyl cation species or acyl cation species are preferred. From the viewpoint of connection formation, it is preferable that at least one species is an acyl cation species. Furthermore, it is particularly preferable that the cation species to be generated are at least two or more containing an acyl cation species.

The counter anion of the cation generator may have the structure of the formula (2), but a fluorine compound is particularly preferable from the viewpoint of impurity ions.

The content of the cation generator in the anisotropic conductive adhesive film of the present invention is 0.01 to 15 parts by mass, preferably 0.5 to 100 parts by mass with respect to 100 parts by mass of the organic binder containing the cationic polymerizable substance. 5 parts by mass. When the content of the cation generator is less than 0.01 parts by mass, the curing becomes insufficient, sufficient electrical connectivity cannot be obtained, and when the content of the cation generator exceeds 15 parts by mass, storage is performed. Sex is reduced.

<Cation scavenger>
The cation scavenger used in the present invention may have any structure as long as it reacts with a cation species generated by thermal decomposition of the cation generator, but a thiourea compound, 4-alkylthiophenol compound, and 4-hydroxy One or more selected from the group consisting of phenyl-dialkylsulfonium salts are preferred.

Specific examples of the cation scavenger are shown below. Examples of the thiourea compound include ethylene thiourea, N, N′-dibutylthiourea, and trimethylthiourea. Examples of the 4-alkylthiophenol compound include 4-methylthiophenol, 4-ethylthiophenol, 4-butylthiophenol and the like. Examples of the 4-hydroxyphenyldialkylsulfonium salt include 4-hydroxyphenyldimethylsulfonium methyl sulfate, 4-hydroxyphenyl-dibutylsulfonium methyl sulfate, and the like.

The content of the cation scavenger in the anisotropic conductive adhesive film of the present invention is 0.1 to 20 parts by mass with respect to 100 parts by mass of the cation generator.

Preferably, the content of the cation scavenger is 0.5 to 10 parts by mass with respect to 100 parts by mass of the cation generator. When the content of the cation scavenger is less than 0.1 parts by mass, the connection reliability is lowered, and when it exceeds 20 parts by mass, the connectivity is lowered.

<Conductive particles>
The conductive particles contained in the anisotropic conductive adhesive film of the present invention is 0.1 to 20% by volume, preferably 0.5 to 15% by volume, based on the total volume of the organic binder. Preferably, it is 1 to 10% by volume. When the content of the conductive particles exceeds 20% by volume, the insulation between adjacent terminals becomes insufficient, and when the content is less than 0.1% by volume, the connectivity decreases. The conductive particles are metal particles such as gold, silver, copper, nickel, silver, lead, tin, or alloys made thereof, such as particles such as solder and silver-copper alloys, conductive particles such as carbon, and conductive materials thereof. The surface is coated with a conductive material using glass, ceramics, or plastic particles, which are conductive particles or non-conductive particles, as nuclei. Particles obtained by metal plating on plastic particles are particularly preferable because they have excellent connection reliability due to elastic deformation.

Plastic particles include epoxy resin, styrene resin, silicone resin, acrylic resin, polyolefin resin, melamine resin, benzoguanamine resin, urethane resin, phenol resin, polyester resin, crosslinked divinylbenzene, NBR, SBR, and other polymers. Species or a combination of two or more nuclei can be used. These plastic particles may contain an inorganic substance such as silicon oxide. By forming Ni plating on these plastic particles by a method such as electroless plating, conductive particles can be obtained, and it is also possible to form a metal layer other than Ni such as gold on the Ni plating. . Furthermore, with conductive particles as the core, the surface of the core is coated with an insulating material, and when pressed, the internal conductive particles eliminate the insulating layer on the surface and allow contact with the connected circuit. It is valid. When such conductive particles are used, it is easy to prevent a short circuit between adjacent terminals, and it can also be used in the case of a connected circuit having a narrow terminal interval.

The particle size of the conductive particles is preferably from 0.1 to 20 μm, more preferably from 1 to 10 μm, and even more preferably from 2 to 8 μm. If the particle size is less than 0.1 μm, the connection is likely to be unstable due to variations in the surface roughness of the connected terminals, and if it exceeds 20 μm, a short circuit between adjacent terminals is likely to occur. The standard deviation of the average particle diameter of the conductive particles is preferably as small as possible, preferably 50% or less of the average particle diameter, more preferably 20% or less, still more preferably 10% or less, and particularly preferably 5% or less. For the measurement of the average particle diameter of the conductive particles, a known method such as a Coulter counter can be used. In order to prevent a short circuit between adjacent terminals, insulating particles may be used in combination as long as the connection resistance is not impaired.

Further, in order to prevent a short circuit, the conductive particles may be localized in the thickness direction of the anisotropic conductive adhesive film by a method of laminating a plurality of layers.

In order to enhance storage stability, it is also effective to pre-encapsulate the cation generator in the organic binder component. As a method for microencapsulation, a known method can be used, but a solvent evaporation method, a spray drying method, a coacervation method, and an interfacial polymerization method are preferably used.

<Organic binder containing cationically polymerizable substance>
The cationically polymerizable substance in the organic binder component is an acid polymerizable or acid curable substance, such as an epoxy resin, polyvinyl ether, or polystyrene. The cationic polymerizable substance may be used alone or in combination of two or more.

As the cationic polymerizable substance, an epoxy resin is preferable. The epoxy resin is preferably a compound having two or more epoxy groups in one molecule. Specifically, a compound having a glycidyl ether group, a glycidyl ester group or an alicyclic epoxy group, a compound obtained by epoxidizing a double bond in the molecule, or a compound having two or more of these substituents is more preferable. Furthermore, a resorcinol type epoxy resin may be used to improve environmental resistance.

In the present invention, the organic binder component is composed of a binder resin and a cationic polymerizable substance, and the binder resin that can be mixed with the cationic polymerizable substance is a thermoplastic resin, a thermosetting resin reactive with an epoxy resin, or the like. Thermoplastic resins that can be mixed with cationically polymerizable substances are compatible with cationically polymerizable substances such as phenoxy resin, polyvinyl acetal resin, polyvinyl butyral resin, alkylated cellulose resin, polyester resin, acrylic resin, urethane resin, and polyethylene terephthalate resin. It is resin with. Among these resins, a resin having a polar group such as a hydroxyl group or a carboxyl group is preferable because of excellent compatibility with the cationic polymerizable resin. The cationically polymerizable substance functions as an organic binder component together with the binder resin after being polymerized or cured by a cation.

<Other ingredients>
The organic binder component used in the present invention can further contain other components. Examples of other components include insulating particles, fillers, softeners, accelerators, anti-aging agents, colorants, flame retardants, thixotropic agents, coupling agents, and ion trapping agents. In the case of solid components such as insulating particles and fillers, these maximum diameters are preferably less than the average particle diameter of the conductive particles. As the coupling agent, a ketimine group, vinyl group, acrylic group, amino group, epoxy group, or isocyanate group-containing silane coupling agent is preferable from the viewpoint of improving adhesiveness.

The content of other components is preferably 50 parts by mass or less, more preferably 20% by mass or less, relative to the organic binder component.

When mixing an organic binder and components such as a cation generator, a cation scavenger and conductive particles, a solvent can be used as necessary. Examples of the solvent include methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, ethyl acetate, butyl acetate, ethylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether acetate, and the like.

<Anisotropic conductive adhesive film>
The anisotropic conductive adhesive film of the present invention may be a single layer film or a film in which a plurality of films are laminated. When laminating a plurality of films, it is also possible to laminate films that do not contain conductive particles.

As a method for producing an anisotropic conductive adhesive film, a coating liquid is prepared by previously mixing conductive particles, a cation generator, an organic binder, and, if necessary, a cation scavenger in a solvent, and then a separator. It can be produced by applying the coating liquid on the top by applicator coating or the like and volatilizing the solvent in an oven.

When laminating a plurality of layers, a laminating method is preferable. In the case of laminating, a method of laminating using a heat roll is exemplified. When laminating using a hot roll, the temperature of the hot roll is preferably lower than the temperature at which the cation generator generates cationic species.

Examples of the separator used for the anisotropic conductive adhesive film include films of polyethylene, polypropylene, polystyrene, polyester, PET, PEN, nylon, vinyl chloride, polyvinyl alcohol, and the like. Preferred resins for the protective film include polypropylene and PET. The separator is preferably subjected to surface treatment such as fluorine treatment, Si treatment or alkyd treatment. The film thickness of the separator is preferably 20 μm or more and 100 μm or less.

The anisotropic conductive adhesive film of the present invention is slit to a desired width and wound in a reel shape as necessary.

The anisotropic conductive adhesive film of the present invention can be suitably used for connection between a liquid crystal display and TCP, TCP and FPC, FPC and printed wiring board, or flip chip mounting in which an IC chip is directly mounted on a substrate.

<Connection method and connection structure using anisotropic conductive adhesive film>
A manufacturing method of a connection structure using an anisotropic conductive adhesive film includes a step of heating and pressurizing a pair of electronic circuit boards having a corresponding electrode arrangement through the anisotropic conductive adhesive film of the present invention. For example, as a connection method using the anisotropic conductive adhesive film of the present invention, a circuit board such as a glass substrate in which a circuit and an electrode are formed by ITO wiring or metal wiring or the like, and a position where the electrode of the circuit board is paired A circuit member such as an IC chip on which electrodes are formed is prepared, and the anisotropic conductive adhesive film of the present invention is attached to a position where the circuit member is arranged on the circuit board, and then the circuit board and the circuit member are respectively attached. The electrodes may be connected by thermocompression bonding after aligning the positions of the electrodes so as to form a pair.

When applying the anisotropic conductive adhesive film, it can be heated and pressurized in order to peel off the separator. The heating and pressing conditions are preferably, for example, heating and pressing at a temperature of 30 ° C. to 80 ° C. and a pressure of 0.1 MPa to 1 MPa for 0.5 seconds to 3 seconds.

The thermocompression bonding is performed at a temperature range of 120 ° C. or higher and 180 ° C. or lower (more preferably 130 ° C. or higher and 170 ° C. or lower, most preferably 140 ° C. or higher and 160 ° C. or lower). It is preferable to heat and pressurize in the pressure range below (more preferably 0.5 MPa to 40 MPa) for 3 seconds to 15 seconds (more preferably 4 seconds to 12 seconds).

It is preferable to connect the opposing connection substrates with a temperature difference of 120 ° C. or less, the temperature difference is more preferably 100 ° C. or less, and even more preferably 70 ° C. or less.
The temperature difference between the substrates can be measured by placing thermocouples on the opposing connection substrates.

By maintaining the above temperature range, pressure range, sticking or thermocompression bonding time, and temperature difference between the substrates, high connection reliability can be obtained, and it is advantageous for the connection of the substrate having low heat resistance, and the warpage of the substrate is reduced. It is possible to provide electrical connection of a circuit board that can be suppressed and that is advantageous for shortening the process time.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
30 g of alicyclic epoxy resin composed of 1,2,3,4-butanetetracarboxylic acid and 3-cyclohexaneoxide-1-methanol ester, 15 g of bisphenol A liquid epoxy resin, 3,4-epoxycyclohexylmethyl-3, 5 g of 4-epoxycyclohexanecarboxylate and 50 g of phenoxy resin having an average molecular weight of 25,000 were dissolved in a mixed solvent of toluene-ethyl acetate (1 to 1) to obtain a solution having a solid content of 50%.

4-Benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate 100 parts by mass, N, N′-diethylthiourea 5 parts by mass, dissolved in γ-butyrolactone, The solution was 50 parts by mass. The resin component 100 in terms of solid mass ratio, 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium, tetrakis (pentafluorophenyl) borate and N, N′-diethylthiourea were added so that the total was 2, and benzoguanamine Conductive particles having an average particle diameter of 3.2 μm, in which a nickel layer having a thickness of 0.2 μm is provided on the surface of particles having a resin core and a gold layer having a thickness of 0.03 μm provided on the outside of the nickel layer, are combined with the whole organic binder. It mix | blended and distributed so that it might become 3 volume% with respect to a product, and obtained the dispersion liquid. Thereafter, the dispersion was applied onto a polyethylene terephthalate film having a thickness of 50 μm and blown and dried at 40 ° C. to obtain an anisotropic conductive adhesive film having a thickness of 20 μm.

Example 2
Aside from using 4-acetyloxyphenyl-benzyl-methylsulfonium tetrakis (pentafluorophenyl) borate in place of 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate in Example 1 Obtained an anisotropic conductive film in the same manner as in Example 1.

Example 3
Instead of 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, 4-benzoyloxyphenyl-o-methylbenzyl-methylsulfonium tetrakis (pentafluorophenyl) borate was used. An anisotropic conductive film was obtained in the same manner as in Example 1 except that it was used.

Example 4
Instead of 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, 4-phenoxycarbonyloxyphenyl-benzyl-methylsulfonium tetrakis (pentafluorophenyl) borate was used. Except for the above, an anisotropic conductive film was obtained in the same manner as in Example 1.

Example 5
Instead of 4-benzyloxycarbonyloxyphenyl-o-methylbenzyl-methylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, 4-methoxyphenyl-β-naphthylmethylmethylsulfonium tetrakis (pentafluorophenyl) borate is used. Then, an anisotropic conductive film was obtained in the same manner as in Example 1 except that 4-hydroxyphenyldimethylsulfonium methyl sulfate was used in place of N, N′-diethylthiourea.

Example 6
In place of 4-benzyloxycarbonyloxyphenyl-o-methylbenzyl-methylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, 4-acetyloxyphenylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate was used, and bisphenol was used. An anisotropic conductive film was obtained in the same manner as in Example 1 except that 15 g of resorcin type epoxy resin was used instead of 15 g of A type liquid epoxy resin.

Example 7
4-acetyloxy 2-methylphenylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate was used in place of 4-benzyloxycarbonyloxyphenyl-o-methylbenzyl-methylsulfonium tetrakis (pentafluorophenyl) borate in Example 1 An anisotropic conductive film was obtained in the same manner as in Example 1 except that.

Comparative Example 1
In place of 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, p-hydroxyphenyl-benzyl-methylsulfonium tetrakis (pentafluorophenyl) borate was used, and N An anisotropic conductive film was obtained in the same manner as in Example 1 except that no N'-diethylthiourea was added.

Comparative Example 2
Instead of 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, 4-methoxycarbonyloxyphenyl-benzyl-methylsulfonium tetrakis (pentafluorophenyl) borate was used. An anisotropic conductive film was obtained in the same manner as in Example 1 except that N, N′-diethylthiourea was not blended.

Comparative Example 3
Except for using 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium hexafluorophosphate in place of 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate in Example 1. Obtained an anisotropic conductive film in the same manner as in Example 1.

Comparative Example 4
Instead of 4-benzyloxycarbonyloxyphenyl-o-methylbenzyl-methylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, 4-hydroxyphenyl-α-naphthylmethyl-methylsulfonium tetrakis (pentafluorophenyl) borate was used. An anisotropic conductive film was obtained in the same manner as in Example 1 except that it was used.

Comparative Example 5
Instead of 4-benzyloxycarbonyloxyphenyl-o-methylbenzyl-methylsulfonium tetrakis (pentafluorophenyl) borate in Example 1, 4-acetyloxyphenyl-α-naphthylmethyl-methylsulfonium tetrakis (pentafluorophenyl) borate An anisotropic conductive film was obtained in the same manner as in Example 1 except that was used.

Comparative Example 6
Except for replacing 4-benzyloxycarbonyloxyphenyl-o-methylbenzylmethylsulfonium tetrakis (pentafluorophenyl) borate of Example 1 with 4-cyanophenyl-benzyl-methylsulfonium tetrakis (pentafluorophenyl) borate, An anisotropic conductive film was obtained in the same manner as in Example 1.

(Connection resistance measurement method)
An anisotropic conductive film with a width of 2 mm is temporarily pasted on a polycarbonate film substrate (surface resistance 200 Ω / sq) with a thickness of 200 μm on which an indium oxide-zinc oxide (IZO) thin film is formed on the entire surface, and a 2.5 mm width crimping head After pressing at 50 ° C., 0.3 MPa and 3 seconds, the polyethylene terephthalate base film is peeled off. A flexible printed wiring board (material polyimide resin, thickness 25 μm) having 200 circuits composed of gold-plated copper wiring (gold plating thickness 0.3 μm) having a wiring width of 80 μm, a wiring pitch of 150 μm and a thickness of 18 μm was temporarily connected to the peeling surface. Thereafter, pressure is applied by pressure at 130 ° C., 8 seconds, and 0.9 MPa using a 1.5 mm wide pressure bonding head. After crimping, the resistance value between adjacent terminals is measured with a four-terminal resistance meter to obtain the connection resistance value.

(Peel strength)
The pressure-bonded flexible printed wiring board is cut into a width of 10 mm, and the 90 ° peel strength is measured using an Instron. The pulling speed was 50 mm / min. The measured value is the peel strength. Judgment criteria are shown below.
α: The peel strength is 700 g / cm or more β: The peel strength is 500 g / cm or more and less than 700 g / cm γ: The peel strength is less than 500 g / cm

(Peel strength after environmental resistance test)
The pressure-bonded printed wiring board is held at 85 ° C. and 85% relative humidity for 100 hours, and then subjected to a cycle test (−40 ° C., 100 ° C., 30 minutes each, 1 hour 1 cycle) for 100 cycles, and then 25 After leaving at 1 ° C. for 1 hour, the peel strength is measured.
The criteria for environmental resistance are shown below.
α: The peel strength is 70% or more of the initial value β: The peel strength is 50% or more and less than 70% of the initial value γ: The peel strength is less than 50% of the initial value

(Storage stability)
The anisotropic conductive film is put in a sealed container and stored at 25 ° C. for 2 weeks, and then the peel strength is measured. The criteria for storage stability are shown below.
α: The peel strength is 70% or more of the initial value β: The peel strength is 50% or more and less than 70% of the initial value γ: The peel strength is less than 50% of the initial value

(Reaction rate measurement)
The epoxy group reaction rate is measured by the epoxy group absorbance ratio by the FT-IR method. A 2 mm wide, 20 mm long anisotropic conductive adhesive film formed on a film substrate is sandwiched between 30 μm thick Teflon (registered trademark) tapes, and a pressure heating head with a width of 2.5 mm is used for 10 seconds, 0. A sample pressed at 3 MPa is prepared. FT-IR measurement is performed before and after pressure bonding, and the epoxy group reaction rate is calculated from the absorbance ratio before and after pressure bonding. As a method for calculating the absorbance ratio of the epoxy group, the methyl group absorption intensity is used as an internal standard, and the reaction rate is calculated by the following formula.

Reaction rate (%) = (1 − ((a / b) / (A / B))) × 100
A: Epoxy group absorption strength before pressure bonding B: Methyl group absorption strength before pressure bonding a: Epoxy group absorption strength after pressure bonding b: Methyl group absorption strength after pressure bonding

Epoxy group reaction rate at 140 ° C. for 10 seconds α: 80% or more β: 50% or more and less than 80% γ: Less than 50%

Epoxy group reaction rate at 80 ° C. for 10 seconds α: Less than 10% β: More than 10% but less than 20% γ: More than 20%

The results are shown in Table 1. Table 2 shows the sum of Hammett constants of the substituents of the phenyl group in the above formula (1).

As is clear from Table 1 above, the examples using the present invention have a lower decrease in peel strength after storage and a lower decrease in peel strength after the environmental resistance test than in the comparative example, and good connection resistance. Show.

Claims

An organic binder comprising a cationically polymerizable substance;
0.01 to 15 parts by mass of the general formula (1) with respect to 100 parts by mass of the organic binder containing the cationic polymerizable substance:

{In Formula (1), Q is a substituted or unsubstituted naphthylmethyl group or a substituted or unsubstituted benzyl group, A is a phenyl group having 1 to 5 substituents, and Q is substituted or unsubstituted When it is a naphthylmethyl group, the sum of Hammett constants of the 1 to 5 substituents is -0.3 to 0, and when Q is a substituted or unsubstituted benzyl group, the Hammett of the 1 to 5 substituents The sum of the constants is 0 to +0.5, R 4 is an alkyl group having 1 to 6 carbon atoms, and Y − is a general formula (2):

[In Formula (2), X is respectively independently fluorine, chlorine, or bromine. ] An anion represented by And 0.1 to 20% by volume of conductive particles based on the total volume of the organic binder containing the cationic polymerizable substance;
An anisotropic conductive adhesive film comprising:
The anisotropic structure according to claim 1, wherein in formula (1), Q is a substituted or unsubstituted naphthylmethyl group, and the sum of Hammett constants of 1 to 5 substituents of A is -0.3 to 0. Conductive adhesive film.
The anisotropic conductive material according to claim 1, wherein in formula (1), Q is a substituted or unsubstituted benzyl group, and the sum of Hammett constants of 1 to 5 substituents of A is 0 to +0.5. Adhesive film.
In the formula (1), A represents the general formula (4):

{In the formula (4), R 1 is a methyl group, an acetyl group, a phenoxycarbonyl group, a benzyloxycarbonyl group, a benzoyl group or a 9-fluorenylcarbonyl group, and R 2 and R 3 are hydrogen, halogen, Or an alkyl group having 1 to 6 carbon atoms. } The anisotropic conductive adhesive film of Claim 1 which is group represented by these.
In the formula (4), R 1 is an acetyl group, a phenoxycarbonyl group, a benzyloxycarbonyl group or a benzoyl group, and R 2 and R 3 is hydrogen or a methyl group, different Hoshirubeden of claim 4 Adhesive film.
In the formula (1), Q is the general formula (3):

{In Formula (3), R 5 is hydrogen, a methyl group, a methoxy group, or a halogen. The anisotropic conductive adhesive film according to claim 1, 4 or 5, which is a substituted or unsubstituted benzyl group, α-naphthylmethyl group or β-naphthylmethyl group represented by
The anisotropic conductive adhesive film according to claim 6, wherein R 5 in formula (3) is hydrogen or a methyl group.
The anisotropic conductive adhesive film according to claim 6 or 7, wherein R 4 in formula (1) is a methyl group.
The anisotropic conductive adhesive film according to any one of claims 6 to 8, wherein X in the formula (2) is fluorine.
The diffusing agent according to any one of claims 1 to 5, comprising a cation scavenger that reacts with a cation species generated from the cation generator, in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the cation generator. Direction conductive adhesive film.
The anisotropic conductive adhesive film according to claim 10, wherein the cation scavenger is at least one selected from the group consisting of a thiourea compound, a 4-alkylthiophenol compound and a 4-hydroxyphenyl-dialkylsulfonium salt.
The anisotropic conductive adhesive film according to any one of claims 1 to 5, wherein at least two kinds of cation species generated from the cation generator are used.
6. The anisotropic conductive adhesive film according to claim 1, wherein the organic binder contains a resorcin type epoxy resin.
A method for manufacturing a connection structure, comprising a step of heating and pressurizing a pair of electronic circuit boards having corresponding electrode arrangements through the anisotropic conductive adhesive film according to any one of claims 1 to 5.
A connection structure obtained by the manufacturing method according to claim 14.
General formula (1):

{In Formula (1), Q is a substituted or unsubstituted naphthylmethyl group or a substituted or unsubstituted benzyl group, A is a phenyl group having 1 to 5 substituents, and Q is substituted or unsubstituted When it is a naphthylmethyl group, the sum of Hammett constants of the 1 to 5 substituents is -0.3 to 0, and when Q is a substituted or unsubstituted benzyl group, the Hammett of the 1 to 5 substituents The sum of the constants is 0 to +0.5, R 4 is an alkyl group having 1 to 6 carbon atoms, and Y − is a general formula (2):

[In Formula (2), X is respectively independently fluorine, chlorine, or bromine. ] An anion represented by } The cation generator represented by these.
An anisotropic conductive film comprising an organic binder having an epoxy group, a cation generator and conductive particles, wherein the epoxy group reaction rate at 80 ° C. for 10 seconds is less than 10%, and at 140 ° C. for 10 seconds. An anisotropic conductive adhesive film having an epoxy group reaction rate of 80% or more.