TWI629691B - Circuit connection material, connector, and method of manufacturing the connector - Google Patents

Abstract

The present invention provides a circuit connecting material comprising an insulating adhesive and conductive particles dispersed in the insulating adhesive, and for electrically connecting the first circuit member and the second circuit member and then, the first The circuit member has a first substrate and a first connection terminal disposed on the first substrate, and the second circuit member has a second substrate and a second connection terminal disposed on the second substrate. The first substrate and/or the second substrate are flexible substrates containing a thermoplastic resin, and the conductive particles have plastic particles and a metal layer covering the plastic particles, and compressive hardness when the conductive particles are subjected to 20% compression displacement of the diameter The K value is 0.20 GPa to 3.2 GPa.

Description

Circuit connection material, connector, and method of manufacturing the connector

The present invention relates to a circuit connecting material, a connector, and a method of manufacturing the connector.

In recent years, the miniaturization, thinning, and high-performance of electronic components have been progressing, and the development of economical high-density mounting technology has been actively carried out. The connection between the electronic component and the fine circuit electrode is difficult to correspond by the existing solder and rubber connector. Therefore, an adhesive which uses an anisotropic conductivity excellent in resolution and a method of joining the film thereof are often used. For example, when a glass of a liquid crystal display is connected to a circuit member such as Tape Automated Bonding (TAB) and a flexible printed circuit (FPC), conductive particles are contained. The anisotropic conductive film is sandwiched between the opposing electrodes and heated and pressurized to maintain the insulation between the adjacent electrodes on the same substrate, and the electrodes of the two substrates are electrically connected to each other. The electronic components of the electrodes are then fixed to the circuit components.

As a substrate for a display module such as a liquid crystal display device or an electronic paper, a flexible substrate such as a plastic substrate is being used in place of the conventional glass substrate, in order to reduce the weight and thickness of the module.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 08-148213

[Patent Document 2] Japanese Patent Laid-Open Publication No. Hei 08-124613

[Patent Document 3] Japanese Patent Laid-Open No. Hei 11-50032

The flexible wiring board usually has a flexible substrate containing a thermoplastic resin and an electrode formed on the flexible substrate. The electrode of the flexible wiring board is mainly a film such as metal.

In order to connect a high-definition circuit, an anisotropic conductive adhesive containing conductive particles is often used as a circuit connecting material. However, when a conventional circuit connecting material is used, there is a problem in that the electrode on the flexible substrate is easily broken or cracked due to heating and pressurization for performing circuit connection.

Therefore, a main object of the present invention is to sufficiently prevent damage of an electrode on a flexible substrate when a circuit member having a flexible substrate is connected by a circuit connecting material containing conductive particles.

The present invention relates to a circuit connecting material comprising an insulating adhesive and conductive particles dispersed in the insulating adhesive. The circuit connecting material of the present invention is for electrically connecting the first circuit member and the second circuit member, and then the first circuit member has a first substrate and a first connection terminal disposed on the first substrate, the first The two circuit members have a second substrate and a second connection terminal disposed on the second substrate. The first substrate and/or the second substrate are flexible substrates containing a thermoplastic resin. The conductive particles have plastic particles and a metal layer (metal coating) covering the plastic particles. The compression hardness K value when the conductive particles are subjected to a 20% compression displacement of the diameter is, for example, 0.20 GPa to 3.2 GPa.

According to the circuit connecting material of the present invention, damage of the electrodes on the flexible substrate can be prevented, and a connection in which the circuit members are electrically connected to each other can be obtained. Connector.

The first substrate may be an integrated circuit (IC) wafer or a flexible substrate, and the second substrate may also be selected from the group consisting of polyimine, polyethylene terephthalate, polycarbonate, and polynaphthalene. A flexible substrate of at least one thermoplastic resin in a group consisting of ethylene dicarboxylate.

The compression hardness K value when the conductive particles are subjected to a 40% compression displacement of the diameter may be 0.29 GPa to 3.4 GPa.

The compression recovery rate of the conductive particles may be from 1% to 90%.

The conductive particles may further have an insulating resin layer provided on the outer side of the metal layer.

The storage elastic modulus E' at a frequency of 10 Hz at 40 ° C after heating at 170 ° C for 10 seconds may also be 0.5 GPa to 2.5 GPa.

In another aspect, the present invention relates to a connector including a first circuit member, a second circuit member, and an adhesive layer, wherein the first circuit member has a first substrate and a first substrate a connection terminal, the second circuit member is disposed opposite to the first circuit member and has a second substrate and a second connection terminal disposed on the second substrate, wherein the adhesive layer is disposed on the first circuit member and the second The first circuit member and the second circuit member are electrically connected between the circuit members and then.

In another aspect, the present invention relates to a method of manufacturing a connector for connecting circuit members, the method of manufacturing comprising the steps of: arranging a circuit connecting material between a first circuit member and a second circuit member, The first circuit member has a first substrate and a first connection terminal disposed on the first substrate, and the second circuit member is opposite to the first circuit member Arranging and having a second substrate and a second connection terminal disposed on the second substrate; heating and pressing the whole in the above state, and using the adhesive layer formed by the circuit connecting material to form the first circuit member and the second The circuit components are electrically connected and then.

The first substrate and/or the second substrate are flexible substrates containing a thermoplastic resin. The above-mentioned adhesive layer is a layer formed of the circuit connecting material of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. All the configurations described in the present specification can be arbitrarily combined within the scope not departing from the gist of the present invention. For example, the numerical value range related to various characteristics can be defined by using the upper limit value and the lower limit value of the numerical range described in the present specification and the numerical value arbitrarily selected from the numerical values described in the examples as the upper limit value or the lower limit value. .

The circuit connecting material of the present embodiment is a composition containing an insulating adhesive and conductive particles.

The insulating adhesive may be a thermoplastic material used for an insulating sheet or the like, or may be a curable resin which is cured by heat or light. A curable resin can be used as an insulating adhesive agent in terms of excellent heat resistance and moisture resistance after the connection. Among them, the epoxy-based adhesive is characterized in that it can be cured in a short period of time and has excellent connection workability, and is excellent in adhesion in terms of molecular structure.

The epoxy-based adhesive mainly contains, for example, an epoxy resin such as a polymer epoxy resin, a solid epoxy resin, or a liquid epoxy resin. Epoxy adhesives can also be used It is intended to contain various resins such as phenoxy resin, polyurethane, polyester, nitrile butadiene rubber (NBR) and rubber, various denaturants such as a curing agent and a coupling agent, and additives such as a catalyst.

The epoxy resin may also be a bisphenol epoxy resin derived from epichlorohydrin, bisphenol A, bisphenol F, bisphenol AD, etc., derived from epichlorohydrin and phenol novolac or cresol novolac. Epoxy novolac resin, naphthalene epoxy resin containing naphthalene ring, glycidylamine, glycidyl ester, biphenyl type epoxy resin and alicyclic epoxy resin having two or more glycidyl groups in one molecule Various epoxy compounds. These epoxy resins may be used alone or in combination of two or more. The epoxy resin is preferably a high-purity product to prevent electromigration, and the high-purity product is formed by reducing the concentration of impurity ions (Na ⁺ , Cl ^{- ,} etc.) and hydrolyzable chlorine to 300 ppm or less.

The hardener may be, for example, an imidazole, a hydrazide, a boron trifluoride-amine complex, a phosphonium salt, an amine imine, a diamine maleimonitrile, a melamine, and a derivative thereof. , a polyamine salt or dicyandiamide, and may also be such a modification. These may be used alone or in combination of two or more. These are anionic or cationically polymerizable catalyst-type hardeners, and it is easy to obtain rapid hardenability. Further, in the case of such a curing agent, the necessity of considering the chemical equivalent is small. In addition, examples of the curing agent include addition polymerization type curing agents such as polyamines, polymer captans, polyphenols, and acid anhydrides. An addition polymerization type hardener may be used in combination with a catalyst type hardener.

A secondary amine or an imidazole containing an activator-type curing agent as an anionic polymerization type or an insulating adhesive agent of the two and an epoxy resin is used for several tens of seconds at a medium temperature of about 160 ° C to 200 ° C. Heated hard for hours or so Therefore, the service life (pot life) is relatively long. As the cationic polymerization type catalyst type curing agent, a photosensitive sulfonium salt which hardens a resin by energy ray irradiation, for example, an aromatic diazonium salt and an aromatic sulfonium salt can be used. The catalyst-type hardener which is activated by heat and hardens the epoxy resin is an aliphatic sulfonium salt or the like. This hardener is characterized by rapid hardenability.

A microencapsulated curing agent is obtained by coating a curing agent with a polymer material such as a polyurethane or a polyester material, a metal thin film such as Ni or Cu, or an inorganic material such as calcium citrate to obtain a microencapsulated curing agent. Hardeners extend the life.

The insulating adhesive may further contain, for example, a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, a dielectric material, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, an isocyanate, and the like. Additional ingredients in the hardener.

The circuit connecting material may also be in the form of a film in terms of operability. Examples of the film forming material which the circuit connecting material may contain include an epoxy resin, an acrylic resin, a polyurethane, a rubber, and the like. In order to obtain high reliability as a circuit connecting material, a phenoxy resin can be used. The phenoxy resin corresponds to a high molecular weight epoxy resin having a weight average molecular weight of 10,000 or more as determined by High-Performance Liquid Chromatography (HLC). In the phenoxy resin, similarly to the epoxy resin, there are bisphenol A type, bisphenol type AD, and bisphenol AF type. Since the phenoxy resin is similar in structure to the epoxy resin, it has good compatibility and good adhesion. The larger the molecular weight of the film-forming material, the easier it is to obtain film formability, and the melt viscosity which affects the fluidity at the time of connection can be set in a wide range. Weight average molecular weight in terms of melt viscosity and compatibility with other resins It can also be 10,000~80000 or 20,000~60000. The resin which is a film-forming material has a compatibility with an epoxy resin by having a polar group such as a hydroxyl group or a carboxyl group, and the like, and a film having a uniform appearance or characteristics can be obtained, and a short reaction obtained by promoting the reaction at the time of hardening can be obtained. Time hardens. In terms of film formability and promotion of the hardening reaction, the amount of the film forming material may be 20% by mass to 80% by mass based on the total of the insulating adhesive. In order to adjust the melt viscosity and the like, a styrene resin, an acrylic resin, or the like may be appropriately mixed.

The film forming material may, for example, be at least one resin selected from the group consisting of polystyrene, polyethylene, polyvinyl butyral, polyethylene formaldehyde, polyimide, polyamine, polyester, Polyvinyl chloride, polyphenylene ether, urea resin, melamine resin, phenol resin, xylene resin, epoxy resin, polyisocyanate resin, phenoxy resin, polyimide resin and polyester urethane resin. The adhesion can be further improved by a resin having a functional group such as a hydroxyl group. Further, these resins (polymers) may be modified by a radical polymerizable functional group.

The insulating adhesive may contain a curing agent that generates free radicals by heating or light, and a radical polymerizable substance.

A curing agent which generates free radicals by heating or light (hereinafter also referred to as "free radical generating agent") is decomposed by heating to generate free radicals. The free radical generating agent is, for example, a peroxidic compound or an azo compound. The free radical generating agent is appropriately selected depending on the target joining temperature, the joining time, the pot life, and the like. In terms of high reactivity and pot life, the free radical generating agent may be an organic peroxide having a half-life of 10 hours at a temperature of 40 ° C or higher and a half-life of 1 minute at a temperature of 180 ° C or lower. In this case, the amount of the curing agent which generates free radicals by heating or light may be from 0.05% by mass to 10% by mass or from 0.1% by mass to 5% by mass based on the mass of the insulating adhesive. .

The hardener which generates free radicals by heating or light, for example, may also be selected from the group consisting of dinonyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide and hydrogen. At least one compound of the oxide. In order to suppress corrosion of the connection terminal of the circuit member, a free radical generator selected from the group consisting of a peroxyester, a dialkyl peroxide, and a hydroperoxide may be used. It is also possible to use a peroxy ester which can obtain high reactivity.

Examples of the dimercapto peroxide include isobutyl peroxide, perylene-2,4-dichlorobenzamide, peroxy-3,5,5-trimethylhexanide, and octyl peroxide. Peroxidic laurel, stearyl peroxide, amber peroxide, benzamidine peroxide, and benzammonium peroxide.

Examples of the peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, and diperoxydicarbonate. -2-ethoxymethoxy ester, bis(2-ethylhexylperoxy)dicarbonate, dimethoxybutyl peroxydicarbonate and bis(3-methyl-3-methoxybutyl) Peroxide) dicarbonate.

Examples of the peroxy esters include: perylene neodecanoate, peroxy neodecanoic acid-1,1,3,3-tetramethylbutyl ester, peroxy neodecanoate-1-cyclohexyl-1-methyl Ethyl ester, third hexyl peroxy neodecanoate, tert-butyl peroxytrimethylacetate, peroxy-2-ethylhexanoic acid-1,1,3,3-tetramethylbutyl ester, 2, 5-dimethyl-2,5-bis(2-ethylhexylperoxy)hexane, peroxy-2-ethylhexanoate-1-cyclohexyl-1-methylethyl ester, peroxidation- Terecyl 2-ethylhexanoate, peroxidation Tert-butyl 2-ethylhexanoate, tert-butyl peroxyisobutyrate, 1,1-bis(t-butylperoxy)cyclohexane, third hexyl isopropyl monocarbonate , tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxy laurate, 2,5-dimethyl-2,5-bis(m-tolylmethyl peroxide) Hexane, tert-butyl isopropyl monocarbonate, tert-butyl peroxy-2-ethylhexyl monocarbonate, and third hexyl peroxybenzoate, and tert-butyl peroxyacetate.

Examples of the peroxy ketal include 1,1-bis(Third hexylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(trihexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-(t-butylperoxy)cyclododecane and 2,2-dual ( Third butyl peroxy) decane.

Examples of the dialkyl peroxide include α,α'-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, and 2,5-dimethyl-2,5-di (Third butyl peroxidation) hexane and tributyl cumene peroxide.

Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

These hardeners which generate free radicals by heating or light may be used alone or in combination of two or more. A decomposition accelerator, an inhibitor, or the like may be combined with a free radical generating agent.

The radically polymerizable substance is a substance having a functional group which is polymerized by a radical. The radically polymerizable substance is, for example, selected from the group consisting of an acrylate, a methacrylate, and a maleimide compound.

Examples of the acrylate and methacrylate include urethane acrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, and diethylene glycol diacrylate. Three E Diol diacrylate, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, 2-hydroxy-1,3-dipropenyloxypropane, 2,2-bis[4-(acrylofluorene) Oxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecyl acrylate, bis(propylene Methoxyethyl)isocyanurate, ε-caprolactone modified tris(propylene oxyethyl)isocyanurate and tris(propylene decyloxyethyl)isocyanurate.

These radically polymerizable substances may be used alone or in combination of two or more. The insulating adhesive of the present embodiment contains at least one viscosity at 25 ° C of 100000 mPa. s~1000000mPa. a free radical polymerizable substance of s. The insulating adhesive may also contain 100000 mPa. s~500000mPa. A free-radical polymerizable substance of s viscosity (25 ° C). The viscosity of the radically polymerizable substance can be measured using a commercially available E-type viscometer.

Among the radically polymerizable materials, particularly excellent adhesion can be obtained by using urethane acrylate or methacrylic acid urethane. A radically polymerizable substance which exhibits heat resistance and is crosslinked by an organic peroxide and exhibits a glass transition temperature (Tg) of 100 ° C or more alone, and urethane acrylate or methacrylic acid. Amino amides are used in combination. Such a radical polymerizable substance is a compound having a dicyclopentenyl group, a tricyclodecanyl group, a triazine ring or a combination thereof. In order to obtain more favorable characteristics, a radically polymerizable substance having a tricyclic fluorenyl group or a triazine ring can also be used.

The insulating adhesive may contain a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone as needed.

The insulating adhesive contains 0.1 parts by weight to 10 parts by weight of a phosphate ester ester based on 100 parts by weight of the total amount of the radical polymerizable substance. The radically polymerizable substance can increase the adhesion strength to the surface of an inorganic substance such as a metal. From the same viewpoint, the amount may be from 0.5 part by weight to 5 parts by weight. The radically polymerizable substance having a phosphate structure is obtained, for example, in the form of a reactant of phosphoric anhydride and 2-hydroxy(meth)acrylate. Specific examples thereof include 2-methylpropenyloxyethyl acid phosphate and 2-propenyloxyethyl acid phosphate. These may be used alone or in combination of two or more.

The maleic imine compound has, for example, two or more maleimine groups. The maleimide compound may, for example, be at least one compound selected from the group consisting of 1-methyl-2,4-bismaleimide benzene, N,N'-meta-phenylene bismale. Imine, N, N'-p-phenylene bismaleimide, N, N'-meta-p-tolyl bismaleimide, N, N'-4, 4-extended biphenyl醯iimine, N,N'-4,4-(3,3'-dimethyl-extended biphenyl) bismaleimide, N,N'-4,4-(3,3' -Dimethyldiphenylmethane)Bismaleimide, N,N'-4,4-(3,3'-diethyldiphenylmethane)Bismaleimide, N,N' -4,4-diphenylmethane bismaleimide, N,N'-4,4-diphenylpropane bismaleimide, N,N'-4,4-diphenyl ether double Maleate, N,N'-3,3'-diphenylfluorene, bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl] Propane, 2,2-bis[3-t-butyl-4,8-(4-maleimidophenoxy)phenyl]propane, 1,1-bis[4-(4-malay) Iminophenoxy)phenyl]decane, 4,4'-cyclohexylene-bis[1-(4-maleimidophenoxy)-2-cyclohexyl]benzene and 2,2-double [4-(4-Maleimine phenoxy)phenyl]hexafluoropropane. These may be used alone or in combination of two or more. The maleic imine compound may also be used in combination with an allyl compound such as allyl phenol, allyl phenyl ether or allyl benzoate.

The circuit connecting material may also contain a filler material, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, an isocyanate, and the like.

If the circuit connecting material contains a filler, the connection reliability and the like can be further improved. The maximum diameter of the filler material may also be smaller than the particle diameter of the conductive particles. The amount of the filler material may also be from 5% by volume to 60% by volume. If the amount of the filler exceeds 60% by volume, the effect of improving the reliability is saturated.

The coupling agent may be, for example, a compound having one or more groups selected from the group consisting of a vinyl group, an acryl group, an amine group, an epoxy group, and an isocyanate group. According to the compound containing these groups, the adhesiveness of an insulating adhesive can be improved.

The K value (K20) when the conductive particles contained in the circuit connecting material are subjected to 20% compression displacement of the diameter, in other words, the K value (K20) when the conductive particles are compression-deformed until the deformation rate reaches 20% (deformation rate) The ratio of the displacement to the diameter of the conductive particles may be 0.20 GPa to 3.2 GPa (20 kgf/mm ² to 320 kgf/mm ² ). K20 can also be 0.29 GPa to 2.4 GPa (30 kgf/mm ² to 240 kgf/mm ² ).

The K value (K40) when the conductive particles are subjected to a 40% compression displacement of the diameter may be 0.29 GPa to 3.4 GPa (30 kgf/mm ² to 350 kgf/mm ² ) or 0.39 GPa to 1.9 GPa (40 kgf/mm ^{2 ).} ~190kgf/mm ² ).

The compression hardness K value is an index of the flexibility of the conductive particles. The K value of the conductive particles was set to 200 ° C using a micro compression tester, and the conductive particles were compressed at a speed of 0.33 mN/s using a planar indenter. According to the stress-strain curve at this time, When the load F (kgf), the displacement S (mm), the radius of the particle (mm) R, the elastic modulus E (kgf/mm ² ), and the Poisson's ratio σ are set, according to the compression formula of the elastic ball ( F=(2 ^1/2 /3)). (S ^3/2 ). (E.R ^1/2 )/(1-σ ² )) Use the formula: K=E/(1-σ ² )=(3/2 ^1/2 ). F. (S ^-3/2 ). (R - ^1/2 ) is obtained. Further, when the deformation ratio X (%) and the diameter D (μm) of the ball are set, the K value can be obtained by the formula: K = 3000F / (D ² .X ^3/2 ) * 10 ⁶ . The deformation rate X is calculated by the formula: X = (S/D) × 100. A prismatic diamond indenter having a square bottom surface having a side of 50 μm can be used as the planar indenter for measuring the K value. The maximum test load in the compression test is, for example, set to 50 mN.

The compression recovery rate of the conductive particles may be 1% to 90% or 10% to 60%. The compression recovery ratio of the conductive particles was measured using a micro compression tester. The compression recovery ratio is defined as a ratio of the ratio of the amount of displacement of the compression tester from the contact of the detected particles to the application of the load of 5 mN to the amount of displacement after the load is released. The platform temperature at which the recovery rate was measured was set to 200 °C.

The conductive particles having the K value and the compression recovery ratio as described above have, for example, the configuration of the embodiment described below.

The conductive particles of the present embodiment have plastic particles and a metal layer covering the plastic particles. The metal layer does not need to be coated over the entire surface of the plastic particles, and may also cover a part of the surface of the plastic particles.

The metal layer contains, for example, various metals selected from the group consisting of Ni, Ni/Au, Ni/Pd, Cu, and NiB. The metal layer can also be plated and steamed A film made by plating, sputtering, or the like. From the viewpoint of improving the insulating properties, the conductive particles may have a layer of an insulating material such as ceria or an acrylic resin covering the metal layer on the outer side of the metal layer.

The diameter of the plastic particles can also be an average of 1 μm to 15 μm. From the viewpoint of high-density mounting, the diameter of the plastic particles may also be an average of 1 μm to 5 μm. The plastic particles may have an average diameter of 2 μm to 5 μm from the viewpoint of maintaining the connection state more stably in the case where the electrode has unevenness in surface unevenness.

The plastic particles include, for example, an acrylic resin selected from the group consisting of polymethyl methacrylate and polymethyl acrylate, a polyolefin resin such as polyethylene, polypropylene, polyisobutylene, and polybutadiene, and a resin in a polystyrene resin.

In view of the ease of control of the compression hardness K value and the compression recovery ratio, plastic particles containing a resin obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, or containing ethylene may be used. A plastic particle of a resin obtained by copolymerizing two or more kinds of polymerizable monomers of an unsaturated group. When two or more polymerizable monomers having an ethylenically unsaturated group are copolymerized to obtain a plastic particle, the non-crosslinkable monomer and the crosslinkable monomer are used in combination to appropriately adjust the total amount of the polymer particles. The polymerization ratio and type can easily control the compression hardness K value and compression recovery rate of the plastic particles. For the non-crosslinkable monomer and the crosslinkable monomer, for example, a monomer described in JP-A-2004-165019 can be used.

The density of the conductive particles contained in the circuit connecting material is determined depending on the fineness of the electrode to be connected and the like. The density of the conductive particles is usually from 1% by volume to 50% by volume based on 100% by volume of the insulating adhesive. on The density of the conductive particles may be from 1% by volume to 30% by volume from the viewpoint of insulation and production cost.

The film-like circuit connecting material (an isotropic conductive adhesive film) can be obtained, for example, by a method comprising the steps of: dissolving the above-mentioned insulating adhesive and a conductive adhesive in a solvent or dispersing in a dispersion medium to prepare a coating liquid; the coating liquid is applied onto a release substrate such as release paper; or the coating liquid is impregnated into a substrate such as a nonwoven fabric, and the coating liquid is dried at a temperature lower than the activation temperature of the curing agent to remove Solvent or dispersion. By using an aromatic hydrocarbon-based and oxygen-containing mixed solvent as a solvent, the solubility of the material can be improved. The latent hardener can be particularly effectively protected by an Solubility Parameter (SP) value of 8.1 to 10.7. The oxygen-containing solvent is, for example, an acetate. The boiling point of the solvent may also be 150 ° C or less. If the boiling point exceeds 150 ° C, drying requires high temperatures. Since the drying temperature is close to the active temperature of the latent curing agent, there is a tendency that the workability is lowered and the workability at the time of drying at a low temperature tends to be lowered. Therefore, the boiling point of the solvent may be from 60 ° C to 150 ° C or from 70 ° C to 130 ° C.

The film-like circuit connecting material may also have a multi-layered adhesive layer. For example, the following anisotropic conductive adhesive film may be used as a circuit connecting material: an adhesive film containing conductive particles (conductive pattern layer) for imparting anisotropic conductivity, and an insulating layer containing no conductive material. An anisotropic conductive adhesive film having a two-layer structure or a three-layer structure including an adhesive film containing conductive particles (conductive pattern) and an insulating layer containing no conductive material provided on both sides thereof To the conductive adhesive film. Conductive particles (conductive patterns) may be present in the plurality of layers.

Since the anisotropic conductive adhesive film having a plurality of layers can efficiently dispose conductive particles (conductive patterns) on the electrodes to be connected, it is advantageous for electrode connection arranged at a narrow pitch. In consideration of the adhesion to the circuit member, it is also possible to laminate a circuit connecting material by laminating a bonding film excellent in adhesion to each circuit member to be connected.

The circuit connecting material of the present embodiment can be used, for example, for low viscosity at 170 ° C or lower by heating for 10 seconds, and the electrodes are electrically connected via conductive particles. The storage elastic modulus E' at a frequency of 10 Hz at 40 ° C of the cured body (adjacent layer) formed by heating the circuit connecting material of the present embodiment at 120 ° C or higher and 170 ° C or lower for 10 seconds may be 0.5 GPa to 2.5. GPa.

The circuit connecting material of the present embodiment can be used for a method of connecting circuit members, the method comprising the steps of: arranging the circuit connecting material between a first circuit member and a second circuit member, wherein the first circuit member has a first substrate and a first connection terminal disposed on the first substrate, wherein the second circuit member is disposed opposite to the first circuit member and has a second substrate and a second connection terminal disposed on the second substrate; Heating and pressurizing are performed integrally, and the first circuit member and the second circuit member are electrically connected by an adhesive layer formed of a circuit connecting material and then.

The first substrate, the second substrate, or both are flexible substrates containing a thermoplastic resin. The flexural modulus of the flexible substrate is, for example, 10 GPa or less.

The flexible substrate has, for example, an organic substrate containing a thermoplastic resin selected from polyimines (polyimi) having relatively high heat resistance. De, PI), and polyethylene terephthalate (PET), polycarbonate (PC) and polyethylene naphthalate (PEN) with relatively low heat resistance .

The flexible substrate may further have one or two or more layers selected from the group consisting of a modified coating film such as a hard coat layer and a protective film, which are formed on the surface of the organic substrate and have improved optical and mechanical properties. A composite material having a glass substrate, stainless steel (Stainless Steel, SUS) or the like can be used as the flexible substrate, and the glass substrate, stainless steel, or the like is bonded as a reinforcing material for facilitating handling and transportation of the substrate. Or configured by coating or the like.

The thickness of the flexible substrate may be about 10 μm to 200 μm or about 10 μm to 125 μm in terms of maintaining the strength of the film and ensuring flexibility in the case of a single body.

Examples of the electrode material for forming the connection terminal provided on the flexible substrate include metals such as Ni, Al, Au, Cu, Ti, and Mo, and Indium Tin Oxide (ITO) and Indium Zinc Oxide. , IZO) and other transparent conductors.

When the second substrate is a flexible substrate, the first substrate may be an IC wafer or a flexible substrate. When the first substrate is an IC wafer and the second substrate is a flexible substrate, a circuit connecting material can be used for the plastic substrate to be connected to the COP. When the first substrate and the second substrate are flexible substrates, a circuit connecting material can be used for the connection of a film on a plastic substrate (FOP).

The first circuit member connected to the second circuit member having the flexible substrate may be an active element such as a semiconductor wafer, a transistor, a diode, a thyristor, a capacitor, or the like. An electronic component such as a passive component such as a resistor or a coil, a printed circuit board, and a glass substrate on which a circuit such as ITO is formed. A bump electrode such as a line bump or the like may be provided as a connection terminal, and the bump electrode such as the above-described line bump is a bump or a gold wire formed by plating by a torch or the like on an electrode pad of a semiconductor wafer or a substrate. The front end is melted to form a gold ball, and the ball is crimped onto the electrode pad, and the wire is cut and obtained.

The connection terminals of the circuit members may be singular, but usually provided in plurality. At least a portion of the connection terminals of the circuit members are disposed to face each other with at least one of the circuit members, and the circuit connection material is inserted between the connection terminals disposed to face each other. Heating and pressurization are performed in this state, whereby the connection terminals arranged to face each other are electrically connected to each other to obtain a connector. The connection terminals arranged to face each other are electrically connected to each other via conductive particles.

Example

Hereinafter, the present invention will be more specifically described by way of examples. However, the invention is not limited to the embodiments.

Example 1

20 parts by weight of acrylamide urethane (product name: UA-5500T, manufactured by Shin-Nakamura Chemical Co., Ltd.) as a radical polymerizable substance, bis(acryloxyethyl)isocyanurate (product name) :M-215, manufactured by Toagosei Co., Ltd.) 15 parts by weight, dimethylol tricyclodecane diacrylate (product name: DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) 5 parts by weight and 2-methyl propylene oxime Oxyethylethyl phosphate (product name: P-2M, manufactured by Kyoeisha Chemical Co., Ltd.) 1 part by weight, benzoyl peroxide (product name: Nyper BMT-K, manufactured by Nippon Oil & Fat) 8 40 parts by mass of polyesteramine obtained by dissolving a polyester urethane resin (product name: UR4800, manufactured by Toyobo Co., Ltd.) in a mixed solvent of toluene/methyl ethyl ketone = 50/50 60 parts by weight of the urethane resin solution was mixed and stirred to obtain a solution of a binder resin (insulating adhesive). In the solution of the adhesive resin, the conductive particles are dispersed in a ratio of 10% by volume with respect to the insulating adhesive, and the conductive particles have polystyrene particles as a core and a surface covering the polystyrene particles from the inside. A nickel layer having a thickness of 0.2 μm and a gold layer having a thickness of 0.04 μm were sequentially disposed, and the average particle diameter was 3 μm. The K value (K20) at 20% compression deformation of the conductive particles was 0.74 GPa (75 kgf/mm ² ), and the K value (K40) at 40% compression deformation was 0.66 GPa (67 kgf/mm ² ), and the compression recovery ratio was 30%. Furthermore, polyfluorene fine particles (product name: KMP-605, manufactured by Shin-Etsu Chemical Co., Ltd.) having an average particle diameter of 2 μm were dispersed in a ratio of 20 parts by weight based on 100 parts by weight of the binder resin to obtain a binder resin, conductive particles, and A coating solution of a circuit connecting material of polyoxynene fine particles. The coating liquid was applied onto a polyethylene terephthalate (PET) film (thickness: 50 μm) surface-treated on one side using a coating device, and the coating film was dried by hot air at 70 ° C. An anisotropic conductive adhesive film (thickness: 20 μm) was formed as a circuit connecting material. The K value of the conductive particles was measured by using a prismatic diamond-shaped planar indenter having a square bottom surface of 50 μm on one side, and compressing under the conditions of a maximum test load of 50 mN and a compression speed of 0.33 mN/sec. test.

Preparing a flexible substrate having a polyimide film (elastic modulus at 25 ° C: 5800 MPa), a SiO ₂ film (thickness 1000 Å) formed on the polyimide film, and An ITO film having a thickness of 2,500 Å as an electrode provided on the SiO ₂ film. An anisotropic conductive adhesive film was sandwiched between the flexible substrate and an IC wafer having bumps of 12 μm × 100 μm. In this state, the temperature of the anisotropic conductive adhesive film was heated to 160° C., and the whole was pressed for 5 seconds with a total connection area at a pressure of 100 MPa to obtain a flexible substrate and a flexible substrate. A connector in which IC chips are connected.

The cross section of the obtained connecting body was observed, and the amount of deformation of the connection terminal (ITO film) of the portion in contact with the conductive particles was measured and found to be 0.5 μm or less. Fig. 1 (a) is a cross-sectional view schematically showing a connecting portion of the connecting body of the first embodiment. As shown in FIG. 1, it was confirmed that the connection terminal 1 (ITO film) on the flexible substrate 10 (polyimine film) was indented by contact with the conductive particles 5, and the connection terminal was secured. 1 is conducted between the bumps 3 of the ITO wafer. The depth of the concave portion of the ITO film formed by contact with the conductive particles is set as the amount of deformation of the electrode. The amount of deformation is the depth of a portion of the concave portion that is not in contact with the conductive particles (a portion other than the concave portion) having the largest displacement from the electrode surface.

Example 2

100 g of bisphenol F type phenoxy resin was dissolved in a mixed solvent of toluene and ethyl acetate in a mass ratio of 50:50 to obtain a bisphenol F type phenoxy resin solution having a concentration of 60% by mass. In addition, bisphenol A-bisphenol F copolymerized benzene 50 g of the oxygen resin was dissolved in a mixed solvent of toluene and ethyl acetate in a mass ratio of 50:50 to obtain a bisphenol A-bisphenol F copolymerization type phenoxy resin solution having a concentration of 45% by mass.

The obtained two phenoxy resin solutions were mixed to obtain a mixed solution. A liquid epoxy resin was added to the mixed solution. The amount of the liquid epoxy resin was adjusted so that the bisphenol F type phenoxy resin: bisphenol A-bisphenol F copolymerized phenoxy resin: liquid epoxy resin was 30:30:40 by mass ratio.

In 100 g of the obtained solution, the same conductive particles as in Example 1 were dispersed in a ratio of 10% by volume based on the insulating adhesive. Further, 2.4 g of an aromatic onium salt as a latent curing agent was further added thereto to obtain a coating liquid. This coating liquid was applied onto a polyethylene terephthalate (PET) film (thickness: 50 μm) surface-treated on one side using a coating device, and dried by hot air at 70 ° C for 5 minutes. An anisotropic conductive adhesive film (thickness: 20 μm) was formed as a circuit connecting material.

A bonded body obtained by connecting a flexible substrate and an IC wafer was produced in the same manner as in Example 1 using the produced anisotropic conductive adhesive film. The cross section of the obtained connecting body was observed, and the amount of deformation of the connection terminal (ITO film) of the portion in contact with the conductive particles was measured and found to be 0.5 μm or less. No damage or cracks in the circuit were observed. It was observed that an indentation was formed on the connection terminal (ITO film) due to contact with the conductive particles.

Comparative example 1

The conductive particles have polystyrene particles as a core, a nickel layer having a thickness of 0.2 μm and a gold layer having a thickness of 0.04 μm which are provided on the surface of the polystyrene particles and are sequentially provided from the inside, and have a thickness of 0.04 μm. The average particle diameter was 3 μm. The conductive particles 20% compression deformation when a K value of 3.43GPa ^{(350kgf / mm 2), 40} % K value of the compression 4.02GPa (410kgf / mm ²⁾ at the time of deformation, the compression recovery rate of 40%. An anisotropic conductive adhesive film was produced in the same manner as in Example 1 except that the conductive particles were used, and a connector of the flexible substrate and the IC wafer was produced using the same.

The cross section of the obtained linker was observed. (b) of FIG. 1 is a cross-sectional view schematically showing a connecting portion of the connecting body of Comparative Example 1. When the amount of deformation of the connection terminal 1 (ITO film) of the portion in contact with the conductive particles 5 was measured, it was 1.0 μm or more, and damage of the circuit was observed.

Comparative example 2

The conductive particles have polystyrene particles as a core, a nickel layer having a thickness of 0.2 μm and a gold layer having a thickness of 0.04 μm which are provided on the surface of the polystyrene particles and are sequentially provided from the inside, and have a thickness of 0.04 μm. The average particle diameter was 3 μm. 350kgf a K value of 20% when the deformation of the conductive particles / mm ^2, 40% K value is modified when 410kgf / mm ^2, the recovery rate of 40%. An anisotropic conductive adhesive film was produced in the same manner as in Example 2 except that the conductive particles were used, and a connector of the flexible substrate and the IC wafer was produced using the same.

The cross section of the obtained connecting body was observed, and the amount of deformation of the connection terminal (ITO film) of the portion in contact with the conductive particles was measured, and as a result, it was 1.0 μm or more, and damage of the circuit was observed.

Reference example 1

The anisotropic conductive adhesive film produced in Example 1 was sandwiched between a glass plate 20 (having a thickness of 0.5 mm, OA-10) and formed on the glass plate 20 The glass substrate of the upper aluminum sputter film electrode (thickness: 2500 Å) and the IC wafer having the bump of 12 μm × 100 μm were heated so that the reaching temperature of the anisotropic conductive adhesive film reached 160 ° C. The whole body was pressed at a pressure of 100 MPa for 5 seconds with respect to the total connection area, and a connection body obtained by connecting the glass substrate and the IC wafer was obtained.

The cross section of the obtained linker was observed. (a) of FIG. 2 is a cross-sectional view schematically showing a connecting portion of the connecting body of Reference Example 1. When the amount of deformation of the connection terminal 1 (ITO film) in the portion in contact with the conductive particles 5 was measured, it was 0.1 μm or less, and no damage or crack of the circuit was observed. Further, the indentation of the electrode formed by the conductive particles for determining whether or not the connection state of the glass substrate was acceptable was not observed.

Reference example 2

A laminate of a glass substrate and an IC wafer was produced in the same manner as in Reference Example 1 except that the anisotropic conductive adhesive film produced in Example 2 was used, and the cross section thereof was observed. The amount of deformation of the electrode in contact with the conductive particles was 0.1 μm or less, and no breakage of the circuit was observed. The indentation of the electrode formed by the conductive particles could not be observed.

Reference example 3

A laminate of a glass substrate and an IC wafer was produced in the same manner as in Reference Example 1 except that the anisotropic conductive adhesive film produced in Comparative Example 1 was used, and the cross section thereof was observed. (b) of FIG. 2 is a cross-sectional view schematically showing a connecting portion of the connecting body of Reference Example 3. The amount of deformation of the connection terminal 1 (electrode) of the portion in contact with the conductive particles 5 was 0.1 μm or less, and no damage of the circuit was observed. An electrode formed by the conductive particles 5 was observed Indentation.

Reference example 4

A laminate of a glass substrate and an IC wafer was produced in the same manner as in Reference Example 1 except that the anisotropic conductive adhesive film produced in Comparative Example 2 was used, and the cross section thereof was observed. The amount of deformation of the electrode in contact with the conductive particles was 0.1 μm or less, and no breakage of the circuit was observed. Indentations of the electrodes formed by the conductive particles were observed.

Table 1 shows the configuration and evaluation results of each of the produced connectors. As shown in the table, according to the embodiment, the indentation can be formed without causing breakage and cracks of the circuit and the circuit connection of the flexible substrate can be performed.

According to the invention, when the circuit member having the flexible substrate is connected by the circuit connecting material containing the conductive particles, the damage of the electrode on the flexible substrate can be sufficiently prevented. For example, according to the present invention, it is possible to reduce breakage of electrodes and cracks on a flexible substrate when a circuit is connected. Health. Further, by optimizing the size and density of the conductive particles, it is possible to ensure a good connection state and connection reliability and to perform high-resolution circuit connection.

1‧‧‧Connecting terminal

3‧‧‧Bumps

5‧‧‧Electrical particles

10‧‧‧Flexible substrate

20‧‧‧ glass plate

1(a) to 1(b) are cross-sectional views schematically showing a connecting portion of a connecting body of an embodiment and a comparative example.

2(a) to 2(b) are cross-sectional views schematically showing a connecting portion of a connecting body of a reference example.

Claims (8)

A circuit connecting material comprising an insulating adhesive and conductive particles dispersed in the insulating adhesive, for electrically connecting a first circuit member and a second circuit member, and then the first circuit member has a first a substrate and a first connection terminal disposed on the first substrate, the second circuit member has a second substrate and a second connection terminal disposed on the second substrate; and the first substrate is an IC chip or contains a thermoplastic a flexible substrate of a resin; the second substrate is a flexible substrate containing a thermoplastic resin, and the conductive particles have plastic particles and a metal layer covering the plastic particles, and 20% of the diameter of the conductive particles is compressed. The compression hardness K value at the time of displacement is 0.20 GPa to 0.74 GPa. The circuit connecting material according to claim 1, wherein the second substrate comprises a compound selected from the group consisting of polyimide, polyethylene terephthalate, polycarbonate, and polyethylene naphthalate. The above flexible substrate of at least one thermoplastic resin in the group. The circuit connecting material according to the first or second aspect of the invention, wherein the conductive particles have a compression hardness K value of 0.29 GPa to 3.4 GPa when the conductive particles are subjected to a 40% compression displacement. The circuit connecting material according to claim 1 or 2, wherein the conductive particles have a compression recovery ratio of 1% to 90%. The circuit connecting material according to claim 1 or 2, wherein the conductive particles further have an outer side of the metal layer Insulating resin layer. The circuit connecting material according to claim 1 or 2, wherein the storage elastic modulus E' at a frequency of 10 Hz at 40 ° C after heating at 170 ° C for 10 seconds is 0.5 GPa to 2.5 GPa. A connector comprising: a first circuit member having a first substrate and a first connection terminal disposed on the first substrate; and a second circuit member disposed opposite to the first circuit member and having a first a second substrate and a second connection terminal disposed on the second substrate; and an adhesive layer disposed between the first circuit member and the second circuit member to electrically connect the first circuit member and the second circuit member And the first substrate is an IC wafer or a flexible substrate containing a thermoplastic resin; the second substrate is a flexible substrate containing a thermoplastic resin, and the above-mentioned adhesive layer is as claimed in claim 1 A layer formed by the circuit connecting material according to any one of the items 6. A method of manufacturing a connector, wherein the connector is a connector to which a circuit member is connected, comprising: a step of arranging a circuit connecting material between the first circuit member and the second circuit member, wherein the first circuit member has a first substrate And a first connection terminal provided on the first substrate, wherein the second circuit member is disposed opposite to the first circuit member and has a second substrate and is disposed on the second substrate a second connection terminal; and heating and pressing the whole in the above state, electrically connecting the first circuit member and the second circuit member by using an adhesive layer formed by the circuit connecting material, and then following the steps And the first substrate is an IC wafer or a flexible substrate containing a thermoplastic resin; the second substrate is a flexible substrate containing a thermoplastic resin, and the circuit connecting material is as in the first to sixth items of the patent application scope The circuit connecting material according to any one of the preceding claims.