TW201900811A - Conductive adhesive, cured product, electronic component, and method of manufacturing electronic component - Google Patents

Abstract

Provided is a conductive adhesive capable of forming a connection structure having excellent voltage resistance and excellent conductive connection reliability. Moreover, provided are a cured product of the conductive adhesive, an electronic component including a member electrically connected using the conductive adhesive, and a method for producing the electronic component using the conductive adhesive. To this end, the conductive adhesive contains conductive particles and is for anisotropic conductive bonding between members by heat compression. The mixing ratio of the conductive particles is 0.01 to 3.5 volume% based on solid content, and a span value of particle distribution of the conductive particles represented by equation (1), the span value = (D90-D10) / D50 is 3.0 or less, wherein D50 is 0.1-20 [mu]m. In addition, it is favorable to contain peroxide having a 10-hour half-life temperature of 50 DEG C or less.

Description

Conductive adhesive, hardened material, electronic component and manufacturing method of electronic component

The present invention relates to a method for producing a conductive adhesive, a cured product, an electronic component, and an electronic component.

With the recent increase in the density of printed circuit boards of electronic devices that are thinner and shorter, as electrical connection of electronic parts, such as the technology of electrical connection between circuit boards and electronic components or electrical connection between circuit boards, Development and improvement of conductive adhesives (for example, Patent Documents 1 and 2). Such a conductive adhesive is applied between the members to be electrically connected, and can be electrically connected in a lightweight and space-saving manner by heating and compression bonding.

Specifically, the conductive adhesive itself is insulating, but by heat and pressure bonding, the conductive particles contained in the conductive adhesive are held between the electrodes and pressed to form a conductive path. As a result, electrical connection between the members can be achieved. On the other hand, the regions that are not held between the electrodes and not under pressure even after thermal compression bonding are because the conductive particles remain dispersed, so the insulation is maintained. Thereby, it is a so-called anisotropic conductive connection structure. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2012-216770 770 [Patent Document 2] Japanese Patent Application Publication No. 2013-045650

[Problems to be Solved by the Invention]

The connection structure system of anisotropic conductivity formed by using the conductive adhesive as described above is maintained in a region not under pressure. Although the insulation property is maintained in the region, conductive particles are present in the region. Therefore, it is necessary to provide an excellent withstand voltage. Sex.

On the other hand, in such a connection structure system, a conductive path is formed by holding a conductive adhesive containing conductive particles between electrodes and pressing them to form a conductive path, which enables stable electrical connection, that is, excellent conductive connection reliability. Sex is necessary. However, with the recent refinement and thinning of electronic devices, it has been difficult to cope with the voltage withstand capability and conductive connection reliability of fine electrodes with narrow pitches.

Therefore, an object of the present invention is to provide a conductive adhesive capable of forming an anisotropic conductive connection structure having excellent voltage resistance and excellent conductive connection reliability, a cured product of the conductive adhesive, and the use of the same. An electronic component of a member that is electrically connected with a conductive adhesive and a method of manufacturing the electronic component. [Means to solve the problem]

In view of the above, the present inventors have intensively devoted to the results of the research, and found that the size of the particle size distribution span (Span) value is a specific range of conductive particles, and the specific mix ratio can be used to solve the above problems and achieve the completion of the present invention. invention.

That is, the conductive adhesive of the present invention is an electrically conductive adhesive containing members conductively bonded to each other by heat pressing, and is characterized in that the proportion of the conductive particles is based on a solid component. When converted into 0.01 to 3.5% by volume, the value of the particle size distribution span of the conductive particles represented by the following formula (1) is 3.0 or less. Span value = (D90-D10) / D50 …… (1) (In formula (1), D50 is 0.1 ~ 20 μm).

The conductive adhesive of the present invention preferably further contains a peroxide.

The conductive adhesive of the present invention preferably has a 10-hour half-life temperature of the peroxide of 50 ° C. or lower. In this case, the conductive adhesive of the present invention is a low-temperature bonding agent in which the conductive particles are low-melting solder particles, and the conductive adhesive is hot-pressed at a temperature below the melting point of the low-melting solder particles.

The conductive adhesive of the present invention is preferably a low-melting-point solder particle as the conductive particle.

The conductive adhesive of the present invention preferably further contains an organic component.

The conductive adhesive of the present invention is preferably that the organic component includes a compound containing an ethylenically unsaturated group and an organic binder.

The conductive adhesive of the present invention preferably has an ethylenically unsaturated bond equivalent of 260 to 1000 in the organic component (except for the case where the solvent is included).

The cured product of the present invention is obtained by curing the conductive adhesive.

The electronic component of the present invention includes a member electrically connected using the conductive adhesive.

The method for manufacturing an electronic part of the present invention is characterized in that the conductive adhesive is applied, and the members are conductively bonded to each other by thermal compression. [Effect of the invention]

According to the present invention, it is possible to provide a conductive adhesive capable of forming an anisotropic conductive connection structure having excellent voltage resistance and excellent conductive connection reliability, a cured product of the conductive adhesive, and use thereof. An electronic component of a member which is electrically connected with the conductive adhesive, and a method for manufacturing the electronic component.

The conductive adhesive of the present invention is a conductive adhesive containing members conductively bonded to each other by heat pressing, and is characterized in that the mixing ratio of the conductive particles is 0.01 as a solid content conversion. ~ 3.5% by volume, and the Span value of the particle size distribution of the aforementioned conductive particles represented by the above formula (1) is 3.0 or less. If the conductive particles are blended in a small amount of 0.01 to 3.5% by volume, it is considered that the conductive particles are insufficient and sufficient conductivity cannot be ensured, but in fact, it is known that no significant decrease in conductivity and increase in withstand voltage occur. The detailed mechanism is not clear, but by reducing the proportion of conductive particles, although there are fewer conductive particles between the electrodes, as a result, every conductive particle that has been held between the electrodes during thermal compression is reduced. The increase in pressure increases the collapse of the conductive particles (one-dimensional contraction in the direction of compression (Z-axis direction) and two-dimensional elongation in the XY direction). Each conductive particle held between the electrodes is in contact with the electrode. Since the area is increased, it is considered that electrical conductivity can be secured. On the other hand, by reducing the ratio of conductive particles, the concentration of dispersed conductive particles in non-electrically connected spaces is lowered to improve insulation. It is considered that the resistance between adjacent electrodes in the XY direction is high. Improved voltage performance.

Furthermore, if the matching ratio of the conductive particles is reduced to 0.01 to 3.5% by volume, and the span value of the particle size distribution of the conductive particles is set to 3.0 or less, an unexpected electrical connection such as an electrode pitch (L / S) of 50/50 ( μm) The connection structure of electrodes with a narrow pitch such as that of the electrode. It is understood that excellent voltage resistance and excellent reliability of conductive connection can be coexisted.

Here, the span value of the particle size distribution of the aforementioned conductive particles is a value indicating the sharpness of the particle size distribution. In the cumulative particle amount curve of the particle size distribution measurement result obtained by the laser diffraction method, the cumulative The particle diameters D10, D50, and D90 when the amount accounts for 10%, 50%, and 90% become values indicating the deviation of the particle size distribution obtained by the formula (D90-D10) / D50. In addition, the mixing ratio (volume%) of the aforementioned conductive particles is the specific gravity of a composition (adhesive) composed of components other than the conductive particles and the true value of the conductive particles measured using a 100 ml specific gravity cup according to JIS K-5400. The specific gravity is calculated by the following formula. (Formula) 搭配 The proportion of conductive particles (volume%) = 100 × (the amount of conductive particles / the true specific gravity of conductive particles) / ((the amount of conductive particles / the true specific gravity of conductive particles) + (a composition other than conductive particles) The amount of the compound / the proportion of the composition other than conductive particles))

In addition, recently, polycarbonates, PET, or the like having a low heat resistance temperature have been used as a base material, and electronic components such as sensors having a low heat resistance temperature are electrically connected to the base material and mounted. However, it is difficult to electrically connect and adhere the conductive adhesive of the aforementioned prior art by low-temperature and rapid heat-pressing of a substrate or an electronic component having a low heat-resistant temperature. In addition, conventionally, the conductive connection of a conductive adhesive containing a low-melting-point solder particle is generally performed by thermal compression at a temperature above the melting point. However, the inventors and others studied the compounding amount of low-melting-point solder particles and then proceeded the hardening reaction at the same time by pressing, and unexpectedly noticed that even in the low-temperature region below the melting point of the low-melting-point solder particles, The low-melting-point solder particles are subsequently solidified and can be electrically connected. That is, in a manner that the hardening reaction can be rapidly performed in a low temperature region below the melting point of the low melting point solder particles, the invention of the present application preferably contains a peroxide having a half-life temperature of 50 ° C. or lower for 10 hours. The low temperature region below the melting point of the low melting point solder particles also becomes a conductive connection. In the case of using such a peroxide having a low half-life temperature, it is considered that since the reactivity is improved, the conductive adhesive is hardened before the conductive particles are sufficiently pressed. On the contrary, the conductive connection becomes difficult. In the present invention, the conductive connection can be made according to the above.

Hereinafter, the components contained in the conductive adhesive of the present invention will be described in detail.

(Conductive Particles) The conductive adhesive of the present invention contains conductive particles as a characteristic constituent as described above.

In the present invention, the span value of the particle size distribution of the conductive particles is 3.0 or less, preferably 2.0 or less, 0.01 to 1.2 is more preferable, 0.05 to 1.05 is more preferable, and 0.1 to 0.9 is most preferable. If the span value is 3.0 or less, it is more preferable because connections with less conductive connection defects can be made. The lower limit of the span value is not particularly limited, but from the viewpoint of ease of manufacture, it is preferably 0.01 or more.

Here, D50 in the formula (1) is 0.1 to 20 μm, preferably 1 to 15 μm, more preferably 2 to 15 μm, more preferably 3 to 10 μm, and most preferably 4 to 8 μm. By setting D50 to 20 μm or less, even fine spaces can be sufficiently conductively connected. On the other hand, by setting D50 to 0.1 μm or more, aggregation of conductive particles in the conductive adhesive can be suppressed. D90 is preferably 1 to 60 μm, more preferably 5 to 30 μm, and more preferably 9 to 15 μm. By setting D90 to 60 μm or less, sufficient insulation can be ensured even in fine places. On the other hand, by setting D90 to 1 μm or more, aggregation of conductive particles in the conductive adhesive can be suppressed. D10 is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, and more preferably 1 to 6 μm. By setting D10 to 20 μm or less, sufficient insulation can be ensured even in fine places. On the other hand, by setting D10 to 0.01 μm or more, aggregation of conductive particles in the conductive adhesive can be suppressed.

(D90-D10) in the formula (1) is preferably 10 μm or less, and more preferably 6.0 μm or less.

In addition, in the present invention, the matching ratio of the conductive particles is 0.01 to 3.5% by volume, preferably 0.1 to 3.0% by volume, more preferably 0.1 to 2.5% by volume, and 0.1 to 2.0 in terms of solid content in the conductive adhesive. Volume% is more preferred. By setting it as such a range, it is possible to improve electrical resistance without reducing the electrical conductivity, and as a result, it is possible to coexist the electrical conductivity and the withstand voltage.

In the present invention, the conductive particles are held between the electrodes, and the members have an electrical connection function. Here, the conductive particle means a particle of a substance having a volume specific impedance of 1 × 10 ⁶ Ω · cm or less, and is not particularly limited.

Examples of the conductive particle system include Au, Ag, Ni, Cu, Pd, and low-melting-point solder particles and carbon particles described later. The conductive particles may be composite particles coated with a metal layer as non-conductive particles such as glass, ceramics, and plastics as a core, and composite particles having the aforementioned non-conductive particles and metal particles or carbon particles. If the conductive particles are the above-mentioned composite particles or heat-fusible metal particles, the conductive particles are deformed by heating and pressing, so that the contact area with the electrode during connection increases, and high reliability can be obtained in particular. In addition, as this conductive particle system, silver-coated copper particles or fine metal particles are often used, and metal particles having a shape connected in a chain shape may be used.

Such a conductive particle is preferably a thermally fusible conductive particle. In particular, it is preferable to use a conductive particle which is melted by thermal compression at 170 ° C. or lower and 2 MPa or lower, and among them, a low melting point solder particle is preferred.

Here, the low-melting-point solder particles mean solder particles having a melting point of 200 ° C. or lower, preferably 170 ° C. or lower, and more preferably 150 ° C. or lower.

In addition, it is preferable that the low melting point solder particles are lead-free solder particles. The so-called lead-free solder particles are defined by JIS Z 3282 (solder-chemical composition and shape), and the lead content rate is 0.10 mass. % Of solder particles.

Low-melting-point solder particles composed of one or more metals selected from tin, bismuth, indium, copper, silver, and antimony are suitably used as the solder particles not containing lead. In particular, an alloy of tin (Sn) and bismuth (Bi) is preferably used from the viewpoint of the balance of cost, workability, and bonding strength.

The content of Bi in such low-melting-point solder particles is 15 to 65% by mass, preferably 35 to 65% by mass, and more preferably selected in a range of 55 to 60% by mass.

By setting the content ratio of Bi to 15% by mass or more, the alloy system starts to melt at about 160 ° C. Furthermore, when the content ratio of Bi is increased, the melting start temperature is reduced, and the melting start temperature becomes 139 ° C. at 20% by mass or more, and the eutectic composition becomes 58% by mass. Therefore, by setting the content ratio of Bi to a range of 15 to 65% by mass, a low melting point effect can be sufficiently obtained, and as a result, a sufficient conduction connection can be obtained even at a low temperature.

As described above, the conductive particles are preferably spherical. Here, the term "spherical conductive particles" refers to those in which the shape of the conductive particles is a recognizable magnification, and the ratio of the major axis to the minor axis of the spherical powder is 1 to 1.5, and contains 90% or more.

The oxygen content of the conductive particles is preferably 100 to 2000 ppm, more preferably 250 to 1400 ppm, and even more preferably 400 to 850 ppm.

The conductive adhesive of the present invention is not particularly limited as long as it is a resin composition in which the conductive particles are converted into solid components at a ratio of 0.01 to 3.5% by volume, and the particle size distribution of the conductive particles is 3.0 or less. Examples of the other components other than the conductive particles include those generally known and commonly used in conductive adhesives. Specific examples include resin components, peroxides, thixotropy imparting agents, wetting and dispersing agents, and antifoaming agents described later.

(Resin component) As the resin component, at least any one of generally known and commonly used thermosetting, hot-melt, ultraviolet-curing, and moisture-curing resins can be used. Among these resins, particularly, electrical connection by thermal compression is easy, so a thermosetting type is preferred. Examples of the thermosetting resin include an ethylenically unsaturated group-containing compound such as an acrylate resin, and an epoxy resin. Among them, a compound containing an ethylenically unsaturated group is particularly preferable.

(Ethylene Unsaturated Group-Containing Compound) The conductive adhesive of the present invention preferably contains an ethylenically unsaturated group-containing compound. In particular, the ethylenically unsaturated group-containing compound is preferably a monomer or oligomer that can be used as a reactive diluent. That is, by preparing a compound having an ethylenically unsaturated bond, for example, a conductive adhesive that can be hot-pressed even at a low temperature and a low pressure of 170 ° C. or lower and 2 MPa or lower can be easily obtained.

As the ethylenically unsaturated group-containing compound, one kind or two or more kinds of compounds may be mixed and used, and a monofunctional or polyfunctional (meth) acrylfluorenyl group-containing compound may be preferably used. In the description of the present case, the so-called (meth) acrylfluorenyl group is a generic term for acrylfluorenyl and methacrylfluorenyl, and the same applies to other similar expressions.

As such a (meth) acrylfluorenyl-containing compound system, for example, a substituted or non-substituted aliphatic acrylate, an alicyclic acrylate, an aromatic acrylate, a heterocyclic-containing acrylate, and these rings can be used Ethylene oxide modified acrylate, epoxy acrylate, aromatic urethane acrylate, aliphatic urethane acrylate, polyester acrylate, polyether acrylate, polyol acrylate, alkyd Acrylates, melamine acrylates, polysiloxanes, polybutadiene acrylates, and methacrylates corresponding thereto.

More specifically, as the monofunctional (meth) acrylfluorene-containing compound system, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) can be used. Hydroxyethyl acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, butoxymethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate Aliphatic (meth) acrylates such as lauryl (meth) acrylate, isodecyl (meth) acrylate, glycerol mono (meth) acrylate, cyclohexyl (meth) acrylate, 4- (formyl) ) Cyclo (5.2.1.02,6) decane, alicyclic (meth) acrylates such as isobornyl (meth) acrylate, phenoxyethyl (meth) acrylate, ( Aromatic (meth) acrylates such as benzyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and aliphatic epoxy modified ( Modified (meth) acrylates such as (meth) acrylates, tetrahydrofurfuryl (meth) acrylates, (meth) acryloxyethyl phthalic acid, γ- (meth) acrylic acid Alkylalkyltrialkoxysilanes and the like.

In addition, as the polyfunctional (meth) acrylfluorene group-containing compound, bisphenol-A-di (meth) acrylate, alkylene oxide modified bisphenol-A-di (meth) acrylate, 1 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, ethylene glycol bis (methyl) Base) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate Ester, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bis [4- (meth) acryloxymethyl] tricyclo [5.2 .1.02,6] decane, bis [4- (meth) propenyloxy-2-hydroxypropyloxyphenyl] propane, isophorone diisocyanate modified urethane (meth) acrylic acid Ester, hexamethylene diisocyanate modified urethane (meth) acrylate, oligosiloxane di (meth) acrylate, trimethylhexamethylene diisocyanate modified urethane (Meth) acrylate, triallyl isocyanurate, Alkenyl (meth) acrylate, allyl (meth) acrylate.

In addition, the following compounds can also be used. (1) Obtained by subjecting 2-hydroxyethyl (meth) acrylate to a urethane addition reaction with the hydroxyl group of liquid polybutadiene via 2,4-toluene diisocyanate Liquid polybutadiene urethane (meth) acrylate, hydrazone (2) is obtained by adding maleic anhydride to maleated polybutadiene, and esterifying 2-hydroxyacrylate Liquid polybutadiene acrylate, (3) Liquid polybutadiene (methyl) obtained by epoxy esterification reaction with carboxyl group of polybutadiene and glycidyl (meth) acrylate Acrylic ester, hydrazone (4) Epoxidized polybutadiene obtained by reacting an epoxidant with liquid polybutadiene, and liquid polybutadiene obtained by esterification reaction with (meth) acrylic acid (methyl (Meth) acrylate, fluorene (5) liquid polybutadiene having a hydroxyl group, liquid polybutadiene (meth) acrylate obtained by a dechlorination reaction with (meth) acrylic acid chloride, and , (6) Liquid hydrogenated 1,2 polybutadiene glycol, which has been hydrogenated to the double bond of liquid polybutadiene with hydroxyl groups at both ends of the molecule, has been converted Hydrogenated liquid allophanate (meth) acrylate, 2-polybutadiene (meth) acrylate.

Examples of these commercially available products include NISSO PB TE-2000, NISSO PBTEA-1000, NISSO PB TE-3000, NISSO PB TEAI-1000 (the above are all manufactured by Nippon Soda), MM-1000-80, MAC-1000-80 (the above are manufactured by Japan Petrochemical Corporation), Poribekku ACR-LC (made by Japan Hydrazine Industry Corporation), HYCAR VT VTR 2000 × 164 (made by Ube Kosan Co., Ltd.), Quinbeam101 (made by Japan Zeon Corporation), Chemlink5000 (manufactured by SARTOMER), BAC-15 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), BAC-45 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), UAT-2000 (manufactured by Kyoeisha Chemical Co., Ltd.), Epolead PB-3600 (daicel Chemical Industrial company), EY RESIN, BR-45UAS (manufactured by Light Chemical Industries), etc.

Among such (meth) acrylfluorenyl-containing compounds, in particular, 2-hydroxy-3-phenoxypropyl acrylate, phenoxyethyl acrylate, 4-hydroxybutyl acrylate, tetrahydro Furfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-propenyloxyethyl phthalic acid, and aliphatic urethane acrylate are preferred.

From the viewpoint of suppressing the generation of bubbles in the coating film during hot pressing in the present invention, it is preferred that the compound containing an ethylenically unsaturated group has a weight reduction rate of 80% or less at 5%, 3 % Or less is preferred, and 1% or less is particularly preferred. The weight reduction rate at 90 ° C is preferably 10% or less, more preferably 5% or less, and particularly preferably 1% or less. Furthermore, the weight reduction rate at 100 ° C is preferably 20% or less, more preferably 10% or less, and particularly preferably 3% or less. Specific examples include phenoxyethyl acrylate, phenoxy polyethylene glycol acrylate, phenol EO modified acrylate, o-phenylphenol EO modified acrylate, and p-cumyl phenol EO. Modified acrylate, nonylphenol EO modified acrylate, N-propylene ethoxyethylhexahydrophthalimide, polypropylene glycol diacrylate, polyethylene glycol diacrylate, trimethylol Propane triacrylate, trimethylolpropane PO modified triacrylate, trimethylolpropane EO modified triacrylate, and the like are preferably phenoxyethyl acrylate, phenol EO modified acrylate, o-phenylphenol EO modified acrylate, N-propylene ethoxyethyl hexahydrophthalimide. The viscosity of the ethylenically unsaturated group-containing compound is preferably 50 dPa · s or less at 25 ° C.

By using such a compound containing an ethylenically unsaturated group, the conductive adhesive of the present invention can reduce the weight reduction rate at the reaction peak temperature of the conductive adhesive to 5% or less, and as a result, can effectively prevent heat Bubbles are generated when pressed. Here, the reaction peak temperature of the conductive adhesive is referred to as a differential thermal and thermogravimetric measurement (hereinafter, simply referred to as "TG / DTA measurement") device at a temperature increase rate of 5 ° C / sec and 30 to 200 ° C. The measured peak temperature of the DTA curve. However, when there are more than two peaks, it is called the initial peak temperature.

As described above, the ethylenically unsaturated group-containing compound is contained in the conductive adhesive, and is preferably formulated so that the ethylenically unsaturated bond equivalent in the organic component excluding the solvent becomes 260 to 1,000. It is preferably 260 to 700, more preferably 350 to 700, particularly preferably 350 to 550, and most preferably 400 to 500. By setting the ethylenically unsaturated bond equivalent to 260 or more, it is possible to suppress hardening shrinkage that occurs during hardening, obtain sufficient adhesive strength, and improve storage stability. Further, by setting the ethylenic unsaturated bond equivalent to 1,000 or less, sufficient hardenability can be obtained. Here, the so-called ethylenically unsaturated bond equivalent is a gram equivalent and a mass per number of ethylenically unsaturated bonds. When the ethylenically unsaturated group is a (meth) acrylfluorenyl group, it is also generally called (meth) acrylic equivalent. For example, when the ethylenically unsaturated group is a (meth) acrylfluorenyl group, it is defined as the mass of an organic component (excluding a solvent in the case of a solvent) per (meth) acrylfluorenyl group. That is, the ethylenically unsaturated bond equivalent can be obtained by dividing the total mass of organic components (excluding solvents in the case of a solvent) and dividing the number of ethylenically unsaturated bonds in the composition.

The blending ratio of the ethylenically unsaturated group-containing compound is preferably 10 to 90% by mass, preferably 30 to 60, more preferably 35 to 55% by mass, and even more preferably 35 to 55% by mass of the total mass of the conductive adhesive. 40 ~ 55 mass%. By setting the compounding ratio of the ethylenically unsaturated group-containing compound to 10% by mass or more with respect to the total mass of the conductive adhesive, sufficient hardenability can be obtained, and the bonding strength is also made better. In addition, by setting the compounding ratio of the ethylenically unsaturated group-containing compound to 90% by mass or less with respect to the total mass of the conductive adhesive, the curing shrinkage can be suppressed, and the bonding strength is also good.

(Organic Binder) When the conductive adhesive of the present invention contains the aforementioned ethylenically unsaturated group-containing compound as a resin component, it is preferable to further contain an organic binder other than the aforementioned compound. By adding an organic binder, the stress generated during heat curing can be reduced, and the bonding strength can be further improved.

The organic binder is an organic resin component, and a natural resin or a synthetic resin generally known and commonly used can be used. As such an organic binder, natural resins such as cellulose and rosin, polyethylene, polypropylene, polystyrene, polycarbonate, polyvinyl chloride, polyvinyl acetate, polyamide, acrylic resin, and polyisocyanate can be used. Synthetic resins such as ethylene phthalate, fluororesin, silicone resin, polyester resin, acetal resin, butyral resin, etc. Among them, an acrylic resin, a butyral resin, and a saturated polyester resin are particularly preferably used, and a saturated polyester resin is more preferable.

Specific examples of the acrylic resin include KURARITY LA2330 of the KURARITY series (manufactured by Kuraray).

Specific examples of the butyral resin include S-LEC BL-1, BL-1H, BL-2, BL-2H, BL-5, BL of Sekisui Chemical S-LEC series (manufactured by Sekisui Chemical Industry Co., Ltd.). -10, BL-10, BL-S, BL-L, etc.

Specific examples of the saturated polyester resin include VYLON 200, 220, 240, 245, 270, 280, 290, 296, 300, 337, 500, 530, 550, 560 of Toyobo VYLON series (manufactured by Toyobo). , 600, 630, 650, BX1001, GK110, 130, 140, 150, 180, 190, 250, 330, 590, 640, 680, 780, 810, 880, 890, etc.

Organic binders are best used in solid form at room temperature (25 ° C) and atmospheric pressure. By using a solid organic binder, the strength after curing of the conductive adhesive can be easily maintained. The Tg (glass transition temperature) of the organic binder is preferably -20 to 150 ° C, preferably 0 to 120 ° C, and more preferably 10 to 70 ° C.

The molecular weight of the organic binder is preferably 1,000 to 100,000, preferably 3,000 to 80,000, and more preferably 5,000 to 60,000. If the molecular weight is 1,000 or more, no bleeding occurs during hardening and stress relaxation can be performed. If the molecular weight is 100,000 or less, it is easy to be compatible with compounds containing an ethylenically unsaturated group and sufficient fluidity can be obtained.

The proportion of the organic binder is preferably 1 to 90% by mass, preferably 3 to 60%, more preferably 5 to 60% by mass, and more preferably 10 to 50% by mass relative to the total mass of the conductive adhesive. %, More preferably 25 to 45% by mass, and particularly preferably 35 to 40% by mass.

(Peroxide) 的 When the conductive adhesive of the present invention contains a compound containing an ethylenically unsaturated group as a resin component, it is preferable to include a peroxide as a polymerization initiator. The peroxide system functions as a polymerization initiator for a resin component such as an ethylenically unsaturated group-containing compound. With peroxides, radical reactions and the like of compounds containing ethylenically unsaturated groups begin. As a result, the conductive adhesive is hardened, and the adhesion between components of the electronic component can be improved.

The peroxide type includes liquid and powdered peroxides, and specific examples include the following materials.

Keto peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and acetone acetone peroxide, 1,1-bis (t-hexylperoxy) -3,3,5-trimethyl ring Hexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, and 1,1-bis ( t-butylperoxy) cyclohexane, and other peroxyketals, 2,2-bis (t-butylperoxy) butane, n-butyl 4,4-di- (t-butyl peroxy Oxy) valerates, peroxyketals such as 2,2-bis (4,4-di- (t-butylperoxy) cyclohexyl) propane, etc., menthol hydroperoxide, diiso Propylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide, etc. Di (2-t-butylperoxyisopropyl) benzene, dicumylperoxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane , T-butylcumyl peroxide, di-t-hexyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-bis (t-butyl Dialkyl peroxides such as hexyne-3, diisobutyl peroxide, bis (3,5,5-trimethylhexyl) peroxide, di Lauryl peroxide, disuccinate peroxide, bis- (3-methylbenzyl) peroxide, benzamyl (3-methylbenzyl) peroxide, diphenyl Dimethyl peroxides such as formamyl peroxide and bis- (4-methylbenzyl) peroxide, di-n-propyl peroxide diisopropyl peroxide, diisopropyl peroxydicarbonate, Dicarbonate of bis (4-t-butylcyclohexyl) dicarbonate, bis (2-ethylhexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, etc., isopropyl Phenylperoxynedecanoate, 1,1,3,3-tetramethylbutylperoxynedecanoate, t-hexylperoxynedecanoate, t-butylperoxyne Decanoate, t-butylperoxypeptanoate, t-hexylperoxypivalate, t-butylperoxypivalate, 1,1,3,3-tetramethyl Butylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexylperoxy) hexane, t-hexylperoxy-2 -Ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxymaleic acid, t-butyl Peroxy-3,5,5-trimethylhexanoate t-butylperoxylaurate, t-butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexylmonocarbonate, t-hexylperoxybenzoate Acid ester, 2,5-dimethyl-2,5-bis (benzidine peroxy) hexane, t-butylperoxyacetate, t-butylperoxy-3-methyl Peroxy esters of benzoate, t-butylperoxybenzoate, and t-butylperoxyallyl monocarbonate, and 3,3 ', 4,4'-tetra ( t-butylperoxycarbonyl) benzophenone.

Among such peroxides, it is particularly preferable to use a liquid. By using a liquid peroxide, a conductive adhesive having excellent storage stability can be obtained. Here, the liquid peroxide refers to a liquid peroxide at room temperature (25 ° C) and atmospheric pressure.

Generally, a powder-based hardener is added to a thermosetting resin composition to function as a latent hardener. However, when the compound containing the aforementioned ethylenically unsaturated group-containing compound is used, it is unexpected to use a liquid The state of the peroxide improves the storage stability of the conductive adhesive. As a result, the liquid peroxide is well dispersed in the conductive adhesive, and the compound containing an ethylenically unsaturated group functions well to promote hardening.

Examples of the liquid peroxide system include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and acetone acetone peroxide, and 1,1-bis (t-hexyl peroxide). ) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -2-methyl Peroxyketals such as cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, n-butyl Peroxycondensation of 4,4-di- (t-butylperoxy) valerate and 2,2-bis (4,4-di- (t-butylperoxy) cyclohexyl) propane Ketones, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl Hydroperoxides such as hydroperoxides, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di -t-hexyl peroxide, di-t-butyl peroxide, and dialkyl groups such as 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 Peroxide, diisobutyl peroxide, bis (3,5,5-trimethylhexyl) peroxide, bis- (3-methylbenzyl) peroxide Oxides, and dihydrazyl peroxides, such as benzamyl (3-methylbenzyl) peroxide, dibenzofluorenyl peroxide, di-n-propyl peroxydicarbonate, peroxide Peroxydicarbonates such as diisopropyl dicarbonate, bis (2-ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, cumyl peroxy neodecanoate , 1,1,3,3-tetramethylbutyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butylperoxy neodecanoate, t-butyl peroxy Oxypeptanoate, t-hexylperoxy pivalate, t-butylperoxy pivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t- Butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butyl Peroxylaurate, t-butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexylmonocarbonate, t-hexylperoxybenzoate, t-butylperoxyacetate, t-butylperoxy Peroxy esters such as oxy-3-methylbenzoate, t-butylperoxybenzoate, and t-butylperoxyallyl monocarbonate, and 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone.

Among them, particularly preferred peroxide systems in the present invention include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t-hexylperoxy) cyclohexane, n-butyl-4,4-di- (t-butylperoxy) valerate and other peroxyketals, 1,1,3,3-tetrakis Hydrogen peroxides such as methylbutyl hydroperoxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide Compounds, di-t-hexyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) -3-hexyne, etc. Dialkyl peroxide, difluorenyl peroxide, peroxycarbonate, and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy 2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy-3,3, 5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, t- Peroxyesters such as butylperoxy-3-methylbenzoate and t-butylperoxybenzoate. Among the above-mentioned particularly preferred peroxides, excellent adhesion can be obtained by using a peroxyester. Among these, in particular, by using an alkyl peroxyester having the following structure, extremely excellent adhesive strength can be obtained. (In the formula, R and R´ represent each independently an alkyl group.)

In addition, powdery peroxides can be suitably used due to the required characteristics (for example, low-temperature rapid curing properties). Examples include bis (4-t-butylcyclohexyl) peroxydicarbonate and the like.

The peroxide system described above uses a 1-minute half-life temperature of 70 to 150 ° C, preferably 80 to 140 ° C, and more preferably 85 to 130 ° C. By setting the 1-minute half-life temperature to 70 ° C or higher, a sufficient usable time can be ensured during use at room temperature. In addition, by setting the half-life temperature at 1 minute to 150 ° C or lower, sufficient hardenability can be secured.

The peroxide system may be used alone, but may be used in combination of plural kinds.

The compounding amount of such a peroxide is 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, and more preferably 3 to 7 parts by mass relative to 100 parts by mass of the ethylenically unsaturated group-containing compound. It can be appropriately selected. By setting the compounding amount of the peroxide to 0.1 parts by mass or more relative to 100 parts by mass of the ethylenically unsaturated group-containing compound, sufficient hardenability can be ensured. By setting the compounding amount of the peroxide to 20 parts by mass or less with respect to 100 parts by mass of the ethylenically unsaturated group-containing compound, sufficient adhesion can be ensured.

(Peroxide with a 10-hour half-life temperature of 50 ° C or lower) The conductive adhesive of the present invention preferably contains a peroxide with a 10-hour half-life temperature of 50 ° C or lower. It preferably contains a peroxide of 20 to 48 ° C, preferably 20 to 45 ° C. In the present invention, by using a peroxide having a 10-hour half-life temperature of 50 ° C. or lower, it can be hot-pressed at a low temperature.

The peroxide system having a 10-hour half-life temperature of 50 ° C. or lower may be in a liquid state or a powder state. Specific examples include the following materials.

Diisobutyl fluorenyl peroxide and other fluorenyl peroxide, di-n-propyl peroxide dicarbonate, diisopropyl peroxide dicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, Peroxydicarbonate such as bis (2-ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, cumyl peroxyneodecanate, 1,1,3,3 -Peroxyesters of tetramethylbutylperoxyneodecanate, t-hexylperoxyneodecanate, t-butylperoxynedecanoate and the like.

The peroxide system having a 10-hour half-life temperature of 50 ° C. or lower preferably has a carbonate skeleton, and more preferably has a dicarbonate skeleton. The peroxide having a dicarbonate skeleton is preferably a peroxide represented by the following structural formula.

R ₁ -O- (C = O) -OO- (C = O) -OR ₂ (In the above formula, R ₁ and R ₂ are independent of each other and represent an alkyl group having 1 to 20 carbon atoms. C1-C20 alkyl substituted C5-C7 cycloalkyl.)

In the above formula, the alkyl group having 1 to 20 carbon atoms which R ₁ and R ₂ can preferably include methyl, ethyl, butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, Decyl and others.

In the above formula, R ₁ and R ₂ may be substituted by an alkyl group having 1 to 20 carbon atoms and a cycloalkyl group having 5 to 7 carbon atoms. Examples include methyl, ethyl, butyl, isobutyl, Alkyl-substituted cyclohexyl, such as pentyl, hexyl, heptyl, octyl, nonyl, decyl and the like.

Examples of the peroxide system represented by the above structural formula include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, and bis (4-t-butylcyclohexyl) peroxydicarbonate. , Di (2-ethylhexyl) dicarbonate, di-sec-butylpercarbonate.

The 10-minute half-life temperature of the aforementioned 10-hour half-life temperature is preferably 110 ° C or less, and more preferably 20-95 ° C.

The 10-hour half-life temperature of the aforementioned 10-hour half-life temperature is preferably below 70 ° C, and more preferably 20-60 ° C.

The aforementioned peroxide system having a half-life temperature of 50 ° C. or lower may be used alone, but may be used in combination of plural kinds.

The matching ratio of the aforementioned 10-hour half-life temperature of 50 ° C or lower peroxide is 0.01 to 30% by mass, more preferably 0.1 to 15% by mass, and 0.3 to 10 with respect to the conductive adhesive except for conductive particles. The mass% is particularly good. If the blending ratio is 0.01% by mass or more, sufficient hardening can be achieved, and 30% by mass or less can obtain a cured product with sufficient strength.

The conductive adhesive of the present invention is a peroxide adhesive having a 10-hour half-life temperature of 50 ° C. or lower, and when the conductive adhesive is conductively connected at a low temperature, the effect may not be impaired. The 10-hour half-life temperature is higher than 50 ° C.

(Thixotropy imparting agent) 触 The conductive adhesive of the present invention is preferably a thixotropy imparting agent. By preparing a thixotropic agent, it is possible to prevent sedimentation of conductive particles having a high specific gravity. The thixotropic agent can be used singly or in combination of two or more kinds.

As the thixotropy imparting agent system, generally known ones can be used, and for example, bentonite, wax, metal stearate, modified urea, silicon dioxide, and the like can be used. Among these, silicon dioxide is preferred. The aforementioned silicon dioxide-based amorphous silicon dioxide is preferred, and amorphous silicon dioxide having an average primary particle size of 50 nm or less is more preferred, and hydrophobic amorphous silicon dioxide having a hydrophobicized surface on the surface is particularly preferred. good.

The matching ratio of such a thixotropy imparting agent is based on the solid content of the conductive adhesive, preferably 0.01 to 20% by mass, preferably 0.1 to 10% by mass, and more preferably 1 to 5% by mass. To choose. By setting the blending ratio to 0.01% by mass or more, it is possible to prevent sedimentation of conductive particles having a high specific gravity, and it is set to 20% by mass or less, so that the adhesion is good.

(Wetting and dispersing agent) 导电 The conductive adhesive of the present invention is preferably formulated with a wetting and dispersing agent. By blending a wetting and dispersing agent, the dispersion of the conductive particles becomes good and the generation of coarse particles due to agglomeration can be prevented. The wetting and dispersing agents can be used singly or in combination of two or more.

As the wetting and dispersing agent, generally known ones can be used. For example, aliphatic carboxylic acid, aliphatic carboxylic acid salt, higher alcohol sulfate, alkyl sulfonic acid, phosphate, polyether, polyester carboxylic acid, or the like can be used. Salt. Among these, phosphate is preferred.

The mixing ratio of such a wet dispersant is preferably 0.01 to 5% by mass in terms of solid content in the conductive adhesive. It is preferably 0.05 to 3% by mass, more preferably 0.1 to 3% by mass, more preferably 0.1 to 1% by mass, and most preferably 0.15 to 0.45% by mass. When the conductive adhesive of the present invention contains a peroxide having a 10-hour half-life temperature of 50 ° C or lower, the conductive adhesive is preferably converted to a solid content of 0.01 to 5% by mass, and more preferably 0.1 to 3 quality%. When the blending ratio is set to 0.01% by mass or more, a moist dispersion effect can be obtained, and when the blending ratio is set to 5% by mass or less, good coating film characteristics can be obtained.

(Defoaming agent) 导电 The conductive adhesive of the present invention is preferably a defoaming agent. By blending a defoamer, it is possible to suppress the generation of bubbles and prevent the generation of pores. The antifoaming agent can be used singly or in combination of two or more kinds.

As the antifoaming agent, a generally known one can be used, and examples thereof include silicone resin, modified silicone resin, organic polymer, and organic oligomer. Among these, an organic polymer or an organic oligomer is preferable, and a polymer of vinyl ether is more preferable.

The matching ratio of such a defoaming agent is based on the solid content of the conductive adhesive, preferably 0.01 to 10% by mass, preferably 0.1 to 5% by mass, and more preferably 0.5 to 3% by mass. select. Setting the blending ratio to 0.01% by mass or more can prevent the occurrence of pores, and setting the blending ratio to 10% by mass or less makes the adhesion better.

(Other components) 导电 The conductive adhesive of the present invention is a generally known and commonly used additive in which a leveling agent or the like can be adjusted as necessary. Moreover, you may mix | blend a resin particle for the purpose of suppressing bleeding of a conductive adhesive, improving adhesiveness, etc. The resin particles are preferably spherical resin particles, and so-called resin beads may also be used.

The conductive adhesive of the present invention preferably does not include a solvent. Here, the "no solvent" refers to the fact that the conductive adhesive does not contain a solvent, and the reduction in mass of the conductive adhesive due to heating at 150 ° C for 30 minutes is compared to the mass before heating. It is 5 mass% or less, preferably 3 mass% or less.

As described above, the conductive adhesive of the present invention is produced by mixing and mixing each of the components described above at a specific mixing ratio, and generally known methods. In particular, a vacuum stirring treatment is preferably applied to the system of the present invention. By vacuum stirring treatment, since the conductive adhesive is decompressed and degassed, bubbles, water, and low-boiling impurities in the conductive adhesive are removed, which can further suppress the generation of bubbles after heating, and because of this The adhesion strength decreases.

Moreover, the conductive adhesive system of this invention can be used suitably for the electrical connection of the components of an electronic component. For example, a glass substrate for a display such as a television can be connected to a Flexible Printed Circuits (FPC: Flexible Printed Circuits) electrically connected to a FOG (Flex on Glass), and an IC for control such as an LSI chip or a liquid crystal screen can be used. Directly connected to transparent electrodes on glass substrates, so-called COG (Chip on Glass) connections, COB (Chip on Board) connections such as mounting LSI chips on rigid printed circuit boards, or mounting LSIs on flexible printed circuit boards Chip on Flex (Chip on Flex) connection, FOB (Flex on Board) connection between flexible printed circuit boards and rigid printed circuit boards, FOF (Flex on Flex) connection between flexible printed circuit boards, etc. It can be used for the electrical connection of glass substrates or printed circuit boards with electronic components or the electrical connection of printed circuit boards with each other. Among them, it is preferable to be used for the electrical connection between a rigid printed circuit board and a flexible printed circuit board. It can also be suitably used for the electrical connection of the wiring for driving a touch panel or a liquid crystal display. In addition, it can be suitably used for electrical connection of a smart phone, a tablet terminal, and a wearable terminal. Furthermore, since the high-frequency characteristics are good, they can also be suitably used for the electrical connection of electronic devices that require high-frequency characteristics.

In particular, the conductive adhesive of the present invention is an electrical connection between components of electronic parts. Even if the electrode pitch (L / S) is narrow, a connection structure having excellent voltage resistance and excellent reliability of conductive connection can be formed. body. As a result, both the L and S of the conductive adhesive-based electrode pitch (L / S) of the present invention can be applied to a case of 200 μm or less, 100 μm or less, 75 μm or less, and 50 μm or less.

When the conductive adhesive of the present invention contains a peroxide having a 10-hour half-life temperature of 50 ° C. or lower, it is conductively connected even at a low temperature, and therefore can be suitably used for low-temperature bonding. The base material to be used is not particularly limited, and may be, for example, a base material having a heat distortion temperature (JIS K7206) of 200 ° C or lower and further lower heat resistance such as 150 ° C or lower. For example, polycarbonate (heat distortion temperature JIS K7206 18.6kgfcm ^-2 129 ~ 140 ° C) or PET (heat distortion temperature JIS K7206 18.6kgfcm ^-2 37.7) having low heat resistance which is electrically conductively connected to the substrate can be suitably used. ~ 41 ° C). In addition, it is also possible to suitably use an electronic component such as a sensor component having a low heat resistance (Tjmax ≦ 150 ° C. (Tjmax: maximum junction temperature)) to be electrically connected to a substrate and mounted. Moreover, it can also be used suitably when the sensor parts are electrically connected by thermocompression. Herein, the "heat resistance" in the present invention means that when the substrate is placed in a high temperature state, it is difficult to generate electrical, physical characteristics such as deformation, structural defects, conduction, insulation strength, and dielectric constant. reduce. The "sensor" in the present invention refers to an element or device that detects information such as images, fingerprints, temperature, pressure, and sound. Examples include CMOS or CCD sensors of camera modules, biometric sensors for detecting fingerprints or veins, vital signs sensors for measuring heartbeat or blood pressure, infrared sensors for positioning, Sonic sensors, pressure sensors to detect contact, thermal sensors to detect heat, gyro sensors to know the angle, etc.

In the case where the conductive adhesive of the present invention contains a peroxide having a 10-hour half-life temperature of 50 ° C. or lower, it can be suitably used for low-temperature bonding for conductive connection at a temperature below the melting point of conductive particles, such as conductive particles. In the case of low-melting-point solder particles (melting point = 139 ° C), it can also be conductively connected at a temperature below the melting point, for example, 120 ° C.

The electrical connection between components of an electronic component using the conductive adhesive of the present invention is performed by, for example, the following method. First, the conductive adhesive of the present invention is applied to an electrical connection place of a connection member such as a printed circuit board by a screen screen or a metal mask, or a coating device such as a dispenser. Rather than coating. Here, the coating method is not particularly limited, and a generally known method can be used.

Next, after confirming that the conductive adhesive is sufficiently supplied to the connection place, the connected member (part) is mounted on the connection place of the connection member (substrate), and is hardened by thermal compression at a specific temperature and a specific pressure. Thereby, the connection member (substrate) and the connected member (part) can be electrically connected.

With the conductive adhesive of the present invention, by setting the ratio of conductive particles to 0.01 to 3.5% by volume, the number of conductive particles held by the electrodes is reduced, because the pressure applied to the conductive particles increases, so At a low temperature and a low pressure, specifically 170 ° C. or lower, further 150 ° C. or lower, 2.0 MPa or lower, 1.5 MPa or lower, and thermal compression of 1.0 MPa or lower, the members may be anisotropically bonded to each other. As a result, at 150 ° C. and a relatively low temperature of 0.8 MPa and a low pressure, the anisotropic conductive bonding can be easily performed.

In the case where the conductive adhesive of the present invention is prepared with a peroxide having a 10-hour half-life temperature of 50 ° C. or lower, the members can be electrically conductively bonded to each other even if they are thermally pressed at a low temperature and a low pressure. The temperature during hot pressing is not particularly limited, but may be, for example, 170 ° C or lower and further 150 ° C or lower, or 130 ° C or lower, further 120 ° C, 110 ° C, or 100 ° C. Hot pressing is performed at a relatively low temperature, such as below 90 ° C. The hot-pressing is preferably performed at 60 ° C or higher, and more preferably at 80 ° C or higher. In addition, the pressure at the time of hot pressing is not particularly limited, but the hot pressing may be performed at a low pressure of 2.0 MPa or less and further at a low pressure of 1.5 MPa or less and 1.0 MPa or less. [Example]

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited to these. In addition, unless otherwise stated, "parts" and "%" are set as quality standards.

(Preparation of Conductive Adhesive) The ingredients and mixing ratios (mass ratios) shown in Tables 3 and 4 below were used to mix and stir the components to prepare the conductive adhesives of the examples and comparative examples. The low-melting-point solder particles having the span values shown in Table 1 below are used as the conductive particles B-1 to B-6. The measurement of the particle size distribution was performed using the following measurement device and measurement conditions.

(Examples 1 to 6, Comparative Examples 1 and 2) (Evaluation of Reliability of Conductive Connection) Test pieces were prepared by using the conductive adhesives of Examples 1 to 6 and Comparative Examples 1 and 2 prepared as described above. On the substrate (base material: FR-4, electrode width: 50 μm, electrode length: 6 mm, pitch width: 0.1 mm, number of U-shaped electrodes 140, linear electrodes 1, rapid Au processing), a metal mask (shielding Cover thickness: 80 μm, opening: 15 mm × 1 mm) and applied by a doctor blade. Next, a flexible substrate (width: 16 mm, substrate: polyimide, electrode width: 50 μm, electrode length: 6 mm, pitch width: 0.1 mm, Number of U-shaped electrodes is 140, number of linear electrodes is 1, fast Au processing). During the placement, the positions of the electrodes of the rigid substrate and the electrodes of the flexible substrate are matched in a daisy chain manner, and the overlapping length of the electrodes on both sides is 3.5 mm. The bonding surfaces of the substrates placed in this manner were heat-pressed at 1.2 MPa, 150 ° C., and 6 seconds to produce a daisy-chain circuit test piece having 140 electrical connection spaces.

After the test piece obtained by the above method was heated to peel off the pressure-bonded portion, the electrode portion of the rigid substrate was washed with acetone. Using the microscope (KEYENCE Corporation, VHX-5000 500-times observation area 542 × 722 μm in length) at the center of the cleaned electrode section (number of U-shaped electrodes 140, linear electrode 1), and observe 7 electrodes. The presence or absence of adhesion of conductive particles was confirmed in the electrode longitudinal direction at 540 μm, and the non-adhered electrode was used as an NG terminal. Perform this operation with 10 test pieces, calculate the number of NG terminals relative to a total of 70 terminals, and evaluate the reliability of the conductive connection. The evaluation criteria are as follows. ◎: The number of NG terminals is 0 ○: The number of NG terminals is 1 ~ 2 △: The number of NG terminals is 3 ~ 4 ×: The number of NG terminals is 5 or more

(Evaluation of withstand voltage) The test pieces were prepared with the conductive adhesives of Examples 1 to 6 and Comparative Examples 1 and 2 prepared as described above, and the rigid substrates α to γ (all based on the conditions in Table 2 below). Material: FR-4, fast Au treatment), coated with a doctor blade through a metal mask (mask thickness: 80 μm, opening: 15 mm × 1 mm). Next, on the rigid substrate in the state where the conductive adhesive has been applied, the flexible substrates α to γ (each of which is a base material: polyimide, rapid Au treatment) under the following conditions are placed. At this time, the positions of the electrodes of the rigid substrate and the electrodes of the flexible substrate are matched so that the withstand voltage can be measured, and the overlapping length of the electrodes on both sides is 3.5 mm. The bonding surfaces of the substrates placed on each other in this manner were heat-pressed at 1.2 MPa, 150 ° C., and 6 seconds to prepare test pieces.

※ Serial numbers common to rigid substrates and flexible substrates. ※ The substrates to be placed are flexible substrates α for rigid substrate α, flexible substrates β for rigid substrate β, and flexible substrates for rigid substrate γ. γ

Measurement of withstand voltage The withstand voltage of the test piece obtained by the above method was measured using a tester (TR8601 HIGH MEGOHM METER manufactured by Advantest).

(Evaluation of Adhesive Strength) The test piece was prepared using the conductive adhesives of Examples 1 to 6 and Comparative Examples 1 and 2 prepared as described above on a rigid substrate (base material: FR-4, electrode width: 100 μm, electrode Length: 6mm, pitch width: 0.2mm, number of electrodes: 70, rapid Au processing), coating with a doctor blade through a metal mask (mask thickness: 80 μm, opening: 15 mm × 1 mm). Next, a flexible substrate (width: 16 mm, substrate: polyimide, electrode width: 100 μm, electrode length: 6 mm, pitch width: 0.2 mm, Number of electrodes: 70, fast Au processing). At this time, the positions of the electrodes of the rigid substrate and the electrodes of the flexible substrate are matched so that the length of the overlap between the electrodes on both sides becomes 3.5 mm. The bonding surfaces of the substrates placed on each other in this manner were heat-pressed at 1.2 MPa, 150 ° C., and 6 seconds to prepare test pieces.

Measurement of Adhesive Strength The adhesive strength of the test piece obtained by the above method was measured using a bonding strength tester (Nordson Advanced Technology Co., Ltd. 4000 Plus) in accordance with JIS K 6854-1 in the vertical direction. Peel and measure and evaluate. The evaluation criteria are as follows. ○: 10N / cm or more △: 5N / cm or more and less than 10N / cm ×: 5N / cm or less

(Calculation method of the proportion of conductive particles (% by volume)) Measure the specific gravity of components (adhesives) other than low melting point solder particles (solder powder) using a 100ml specific gravity cup (YOSHIMITSU Seiki Co., Ltd.) in accordance with JIS K-5400. Using the true specific gravity of the low melting point solder particles (solder powder), the volume% was calculated by the following formula. In fact, the true specific gravity of 42Sn-58Bi is 8.6, and the specific gravity of components (adhesives) other than low melting point solder particles (solder powder) is 1.13. (Formula) 搭配 Proportion of conductive particles (volume%) = 100 × (The blending amount of solder powder / the true specific gravity of solder powder) / ((The blending amount of solder powder / the true specific gravity of solder powder) + (Composition other than solder powder) The blending amount of the material / the proportion of the composition other than the solder powder))

＊ 1: Ethylene unsaturated group-containing compound (A-1): 2-hydroxy-3-phenoxypropyl acrylate (ARONIX M-5700 manufactured by Toa Kosei, molecular weight: 222, Tg: 17 ° C, viscosity : 1.65dPa · s / 25 ° C) * 2: Compound containing ethylenically unsaturated group (A-2): phenoxyethyl acrylate (light acrylate PO-A manufactured by Kyoeisha Chemical Co., Ltd., molecular weight: 192, Tg : -22 ° C, viscosity: 0.125dPa · s / 25 ° C) * 3: Compound containing ethylenic unsaturated group (A-3): aliphatic urethane acrylate (EBECRYL270 manufactured by DAICEL-ALLNEX Corporation) Molecular weight: 1500, Tg: -27 ° C, viscosity: 30dPa · s / 60 ° C) * 4: Saturated polyester resin (VYLON337, manufactured by Toyobo Co., Ltd., molecular weight: 10,000, Tg: 14 ° C) * 5: 1,1, 3,3-tetramethylbutylperoxy-2-ethylhexanoate (PEROCTA O, manufactured by Nippon Oil Co., Ltd., properties: liquid, 1-minute half-life temperature: 124.3 ° C, 10-hour half-life temperature: 65.3 ° C) * 6: Low melting point solder particles 42Sn-58Bi [spherical particles composed of 42Sn-58Bi]) * 7: Phosphate ester (LIGHT ESTER P-2M manufactured by Kyoeisha Chemical Co., Ltd.) * 8: Vinyl ether polymer (Kyoeisha Chemical Division manufactured FLOWLEN AC-326F) * 9: silicon dioxide particles [specific surface area of 170m ² / g] (manufactured by Japan AEROSIL AEROSIL R974) * 10: L / S = 100μm / 100μm * 11: L / S = 75μm / 75μm ＊ 12: L / S = 50μm / 50μm ＊ The ethylenically unsaturated bond equivalents included in the organic components of the resin composition (conductive adhesive) of each example and comparative example are those of Examples 1 to 6 and Comparative Examples Both 1 to 2 have 465 (the examples and comparative examples are solvent-free). (Calculation method of ethylenically unsaturated bond equivalent in organic component) (Total mass of organic component) / (Number of ethylenically unsaturated bonds in composition) = 90 / 0.1937 = 465

As is clear from the results shown in Table 3, the conductive adhesive system including conductive particles having a mixing ratio of 0.01 to 3.5% by volume in terms of solid content and a particle size distribution span of 3.0 or less can be formed to have excellent voltage resistance. An anisotropic conductive connection structure with excellent conductive connection reliability.

(Examples 7 to 18, Comparative Examples 3 and 4) (Confirmation of hardenability and evaluation of adhesion strength) Production of test pieces The conductive adhesives of Examples 7 to 18 and Comparative Examples 3 and 4 prepared as described above, On a rigid substrate (base material: FR-4, electrode width: 100 μm, electrode length: 6 mm, pitch width: 0.2 mm, number of electrodes 70, rapid Au processing), a metal mask (shield thickness: 80 μm, opening : 15 mm × 1 mm) and applied by a doctor blade. Next, a flexible substrate (width: 16 mm, substrate: polyimide, electrode width: 100 μm, electrode length: 6 mm, pitch width: 0.2 mm, Number of electrodes: 70, fast Au processing). At this time, the positions of the electrodes of the rigid substrate and the electrodes of the flexible substrate are matched so that the length of the overlap between the electrodes on both sides becomes 3.5 mm. The bonding surfaces of the substrates placed on each other in this manner were heat-pressed at 1.2 MPa, 120 ° C., and 5 seconds to prepare test pieces.

Confirmation of hardenability The flexible substrate portion of the test piece obtained by the above method was held by a clamp and lifted upward, and the rigid substrate and the flexible substrate were lifted without peeling, or were only flexible The board was peeled off and it was confirmed that it was hardened.

Measurement of subsequent strength The adhesive strength of the test piece obtained by the above method was used to peel the flexible substrate in a vertical direction in accordance with JIS K 6854-1 using a bonding strength tester (4000 Plus manufactured by Nordson Advanced Technology). Measurement and evaluation.

(Evaluation of Reliability of Conductive Connection) Test pieces were prepared using the conductive adhesives of Examples 7 to 18 and Comparative Examples 3 and 4 prepared as described above on a rigid substrate (base material: FR-4, electrode width: 50 μm). , Electrode length: 6mm, pitch width: 0.1mm, number of U-shaped electrodes 140, linear electrodes 1, fast Au processing, borrowed through a metal mask (shield thickness: 80μm, opening: 15mm × 1mm) Coated by doctor blade. Next, a flexible substrate (width: 16 mm, substrate: polyimide, electrode width: 50 μm, electrode length: 6 mm, pitch width: 0.1 mm, Number of U-shaped electrodes is 140, number of linear electrodes is 1, fast Au processing). During the placement, the positions of the electrodes of the rigid substrate and the electrodes of the flexible substrate are matched in a daisy chain manner, and the overlapping length of the electrodes on both sides is 3.5 mm. The bonding surfaces of the substrates placed in this manner were heat-pressed at 1.2 MPa, 120 ° C., and 5 seconds to produce a daisy-chain circuit test piece having 140 electrical connection spaces.

After the test piece obtained by the above method was heated to peel off the pressure-bonded portion, the electrode portion of the rigid substrate was washed with acetone. Seven electrodes were observed at the center of the cleaned electrode portion (number of U-shaped electrodes: 140, linear electrode 1) using a microscope (VHX-5000 500 times observation area by KEYENCE Corporation, 542 x 722 μm in length). The presence or absence of adhesion of the conductive particles was confirmed at 540 μm in the electrode longitudinal direction, and the non-adhered electrode was used as an NG terminal. This operation was performed with 10 test pieces, and the number of NG terminals relative to a total of 70 terminals was calculated to evaluate the reliability of the conductive connection. The evaluation criteria are as follows. ◎: The number of NG terminals is 0 ○: The number of NG terminals is 1 ~ 2 △: The number of NG terminals is 3 ~ 4 ×: The number of NG terminals is 5 or more

(Evaluation of withstand voltage) 制作 Production of test pieces The respective conductive adhesives of Examples 7 to 18 and Comparative Examples 3 and 4 prepared as described above, and the rigid substrates α to γ (all based on the conditions in Table 2 below) Material: FR-4, fast Au treatment), coated with a doctor blade through a metal mask (mask thickness: 80 μm, opening: 15 mm × 1 mm). Next, on the rigid substrate in the state where the conductive adhesive has been applied, the above-mentioned flexible substrates α to γ are mounted (all of which are substrates: polyimide, rapid Au treatment). At this time, the positions of the electrodes of the rigid substrate and the electrodes of the flexible substrate are matched so that the withstand voltage can be measured, and the overlapping length of the electrodes on both sides is 3.5 mm. The bonding surfaces of the substrates placed on each other in this manner were heat-pressed at 1.2 MPa, 120 ° C., and 5 seconds to prepare test pieces.

Measurement of withstand voltage The withstand voltage of the test piece obtained by the above method was measured using a tester (TR8601 HIGH MEGOHM METER manufactured by Advantest).

(Calculation method of the proportion (volume%) of conductive particles) 体积 Calculate the volume% by the same method as described above.

＊ 1: Compound (A-1) with ethylenically unsaturated bond: 2-hydroxy-3-phenoxypropyl acrylate (ARONIX M-5700 manufactured by Toa Kosei, molecular weight: 222, Tg: 17 ° C, viscosity : 1.65dPa · s / 25 ° C) * 2: Compound having ethylenically unsaturated bond (A-2): phenoxyethyl acrylate (light acrylate PO-A manufactured by Kyoeisha Chemical Co., Ltd., molecular weight: 192, Tg : -22 ° C, viscosity: 0.125dPa · s / 25 ° C) * 3: Compound having ethylenic unsaturated bond (A-3): aliphatic urethane acrylate (EBECRYL270 manufactured by DAICEL-ALLNEX Corporation, molecular weight : 1500, Tg: -27 ° C, viscosity: 30dPa · s / 60 ° C) * 4: Saturated polyester resin (VYLON337, manufactured by Toyobo Co., Ltd., molecular weight: 10000, Tg: 14 ° C) * 13: Diperoxydicarbonate di ( 4-t-butylcyclohexyl) ester (TCP (90% purity) manufactured by Nippon Oil Co., 1 minute half-life temperature: 92.1 ° C, 1-hour half-life temperature: 57.5 ° C, 10-hour half-life temperature: 40.8 ° C) * 14: Over Diisobutyl oxide dicarbonate (PEROYL IPP (50% purity) manufactured by Nippon Oil Co., Ltd., 1 minute half-life temperature: 88.3 ° C, 1-hour half-life temperature: 56.2 ° C, 10-hour half Lifetime temperature: 40.5 ° C) * 15: Di (2-ethylhexyl) peroxydicarbonate (PEROYL OPP (purity 70%) manufactured by Nippon Oil Co., Ltd., 1-minute half-life temperature: 90.6 ° C, 1-hour half-life temperature: 59.1 ℃, 10-hour half-life temperature: 43.6 ° C) * 16: Di-sec-butyl peroxydicarbonate (PEROYL SBP (50% purity) manufactured by Nippon Oil Co., Ltd., 1-minute half-life temperature: 92.4 ° C, 1-hour half-life temperature: 57.4 ℃, 10-hour half-life temperature: 40.5 ° C) * 6: Low melting point solder particles (42Sn-58Bi [spherical particles composed of 42Sn-58Bi) * 7: Phosphate ester (Light Ester P-2M manufactured by Kyoeisha Chemical Co., Ltd.) * 8: Vinyl ether polymer (FLOWLEN AC-326F, manufactured by Kyoeisha Chemical Co., Ltd.) * 9: Silicon dioxide fine particles [specific surface area 170m ² / g] (AEROSIL R974, manufactured by Japan Aerosil Corporation) * 17: (of organic ingredients Calculation method of ethylenically unsaturated bond equivalent) (total mass of organic components) / (number of ethylenically unsaturated bonds in composition)

As can be seen from the results shown in Table 4, the ratio of solid particles is 0.01 to 3.5% by volume, and conductive particles with a particle size distribution span of 3.0 or less and peroxides having a 10-hour half-life temperature of 50 ° C or less are included. The conductive adhesive is an anisotropic conductive connection structure which has excellent voltage resistance and excellent conductive connection reliability, and is conductively connected at a low temperature.

Claims (12)

A conductive adhesive, which is a conductive adhesive that is used to heat conductively bond members to each other by heat and pressure, and contains conductive particles, and is characterized in that: The mixing ratio of the foregoing conductive particles is 0.01 to 3.5 in terms of solid content conversion. Vol%, The span (Span) value of the particle size distribution of the aforementioned conductive particles represented by the following formula (1) is 3.0 or less, Span value = (D90-D10) / D50 ...... (1) (In formula (1), D50 is 0.1 ~ 20 μm). The conductive adhesive as claimed in claim 1, which further comprises a peroxide. The conductive adhesive according to claim 2, wherein the 10-hour half-life temperature of the aforementioned peroxide is 50 ° C or lower. The conductive adhesive according to claim 1, wherein the aforementioned conductive particles are low-melting-point solder particles. The conductive adhesive according to claim 1, further comprising an organic component. The conductive adhesive according to claim 5, wherein the organic component includes: a compound containing an ethylenically unsaturated group and an organic binder. For example, the conductive adhesive according to claim 5, wherein the ethylenic unsaturated bond equivalent in the organic component (except for the case where the solvent is included) is 260 to 1,000. For example, the conductive adhesive according to claim 6, wherein the ethylenic unsaturated bond equivalent in the organic component (except for the case where the solvent is included) is 260 to 1,000. For example, the conductive adhesive of claim 3, wherein the conductive particles are low-melting-point solder particles, and the conductive adhesive is a low-temperature bonding agent that is hot-pressed at a temperature below the melting point of the low-melting solder particles. A hardened material obtained by hardening the conductive adhesive of any one of claims 1 to 9. An electronic component comprising a member electrically connected using the conductive adhesive of any one of claims 1 to 9. A method for manufacturing an electronic part, comprising applying the conductive adhesive of any one of claims 1 to 9, and bonding members to each other by heat pressing.