KR100710957B1 - Anisotropic-electroconductive adhesive, circuit connection using the same, and circuit connection structure - Google Patents

Abstract

The present invention relates to an anisotropic conductive adhesive that can be used for electrical connection of fine circuits, a circuit connection method using the same, and a circuit connection structure. Anisotropically conductive adhesives provided according to the present invention, the insulating adhesive component; And a coating layer made of an insulating thermoplastic resin formed on the surface of the conductive particles, and a plurality of insulating coated conductive particles dispersed in the insulating adhesive component, wherein the softening point of the insulating thermoplastic resin is higher than the exothermic peak temperature of the insulating adhesive component. It is characterized by low. According to the present invention, since the circuit connection can be performed at a low temperature in a short time, and the short circuit of the circuit can be prevented even when the conductive particles are aggregated without poor conduction, the circuit connection structure is very useful.

Circuit, Anisotropic Conductive Adhesive, Insulating Coating Conductive Particles

Description

Anisotropic Conductive Adhesive, Circuit Connection Method and Circuit Connection Structure Using the Same {Anisotropic-electroconductive adhesive, circuit connection using the same, and circuit connection structure}

1 is a schematic diagram showing a conventional anisotropic conductive adhesive sandwiched between substrates having opposite circuit electrodes;

2 is a schematic diagram showing a circuit connection structure electrically connected by a conventional anisotropic conductive adhesive,

3 is a schematic diagram showing a short circuit phenomenon of a circuit connection structure electrically connected by a conventional anisotropic conductive adhesive,

4 is a cross-sectional view showing an anisotropic conductive adhesive according to an embodiment of the present invention,

5 is a cross-sectional view showing insulating coated conductive particles dispersed in the anisotropic conductive adhesive of the present invention,

6 is a schematic view showing the anisotropic conductive adhesive of the present invention interposed between substrates having circuit electrodes opposed to each other,

It is a schematic diagram which shows the circuit connection structure electrically connected by the anisotropically conductive adhesive agent of this invention.

            Description of the main parts of the drawing

10: upper plate 20: lower plate

11, 21: circuit electrode 30: conventional anisotropic conductive adhesive

40: insulating adhesive component 50: conventional conductive particles

130: anisotropic conductive adhesive of the present invention 140: insulating adhesive component

150: insulating coating electroconductive particle of this invention 151: electroconductive particle

152: insulating thermoplastic coating layer 153: nuclear material

154: metal foil layer

The present invention relates to an anisotropic conductive adhesive, a circuit connection method and a circuit connection structure using the same, and more particularly, a connection between a liquid crystal display (LCD) and a flexible circuit board or a tape automated bonding (TAB) film, The present invention relates to an anisotropic conductive adhesive that can be used for a structure that requires electrical connection of minute circuits, such as a connection between a TAB film and a printed circuit board and a semiconductor IC and an IC mounted circuit board, and a circuit connection method and circuit connection structure using the same.

With the development of technology, recent electronic devices have been rapidly miniaturized and thinned. As a result, the connection between the fine circuits or the connection between the micro components and the fine circuits has been dramatically increased. Anisotropic conductive adhesives are used for the connection of such fine circuits. The method of connecting a microcircuit using the conventional anisotropic conductive adhesive is as follows.

Referring to FIG. 1, an insulating adhesive component 40 and an insulating adhesive component 40 are formed between circuit electrodes 11 and 21 provided on the lower surface of the plate 10 and the upper surface of the lower plate 20 so as to face each other. An anisotropic conductive adhesive 30 composed of a plurality of conductive particles 50 dispersed in 40 is interposed. Then, when thermally compressed at a predetermined temperature and pressure, as shown in FIG. 2, the circuit electrodes 11 and 21 to which the conductive particles 50 interposed between the circuit electrodes 11 and 21 are opposed are electrically connected. At the same time, insulation is ensured between adjacent circuits. In addition, as the insulating adhesive component 40 is completely cured, the upper plate 10 and the lower plate 20 are firmly adhered to each other. However, in the conventional anisotropic conductive adhesive, when the conductive particles 50 dispersed in the insulating adhesive component 40 are agglomerated (A in FIG. 3), a short circuit occurs due to electrical connection between adjacent circuit electrodes. There is a problem.

On the other hand, if the adhesive component used for the conventional anisotropic conductive adhesive is largely classified, it can be classified into the thermoplastic type which melt | dissolves and adheres, and the thermosetting type which hardens | cures and adhere | attaches by heating. The anisotropic conductive adhesive using a thermoplastic resin as an adhesive component needs to control the heating temperature above the melting temperature of the resin at the time of bonding. However, depending on the selection of the adhesive resin, the anisotropic conductive adhesive can be connected at a relatively low temperature and is accompanied by a chemical reaction. Since it was not, it was able to connect in a short time. For this reason, the damage by the heat of a to-be-adhered material was restrained low. However, the heat resistance, moisture resistance, and chemical resistance of the connecting portion when connecting a circuit using such an adhesive have limitations in terms of the properties of the adhesive component, resulting in problems in connection reliability and stability.

The anisotropic conductive adhesive using a thermosetting resin as an adhesive component needs to be the curing temperature of the thermosetting resin using the heating temperature at the time of bonding. In addition, in order to obtain sufficient adhesive strength and connection reliability, it is necessary to sufficiently proceed the curing reaction, and it is necessary to maintain the heated state at around 150 ° C to 200 ° C for about 30 seconds. However, since heat resistance, chemical resistance, and moisture resistance are excellent after sufficient heat hardening, this type of anisotropic conductive adhesive is the mainstream now.

Among the thermosetting resins, epoxy resin-based adhesives have been mainly used, and epoxy resin-based adhesives have high adhesive strength and are excellent in water resistance and heat resistance, and are widely used in various applications such as electric, electronic, construction, automobile, and aircraft. have. Among them, one-component epoxy resin adhesives are used in the form of films, pastes, and powders because they do not require mixing of the main component and the curing agent and are easy to use. However, although the epoxy resin film adhesive was excellent in workability, the heating of 150 degreeC-about 180 degreeC was required at the connection time of about 20 second, and the heating of about 180 degreeC-210 degreeC was required in 10 second.

However, conventional epoxy adhesives have problems such as thermal damage to the adherend or numerical change due to thermal expansion shrinkage because the work is performed at a high temperature, and shortening the connection time to 10 seconds or less is required to improve production efficiency. It is becoming.

Accordingly, the technical problem to be solved by the present invention is to solve the above problems and to allow a circuit connection at a low temperature in a short time, and to prevent a short circuit of the circuit even when the conductive particles are aggregated, and also have high reliability without poor conduction. It is to provide an anisotropic conductive adhesive.

Another object of the present invention is to provide a circuit connection method using the anisotropic conductive adhesive.

Another object of the present invention is to provide a circuit connection structure using the anisotropic conductive adhesive.

Anisotropically conductive adhesive according to the present invention provided to achieve the above technical problem, an insulating adhesive component containing a radically polymerizable compound and a polymerization initiator, the exothermic peak temperature is 80 ℃ to 120 ℃; And a plurality of insulating coated conductive particles formed on the surface of the conductive particles and having a coating layer made of an insulating thermoplastic resin and dispersed in the insulating adhesive component at 0.1 to 30 parts by volume with respect to 100 parts by volume of the insulating adhesive component. The polymerizable compound is at least one selected from the group consisting of an acrylate compound or a methacrylate compound, and the polymerization initiator is at least one selected from the group consisting of a peroxide compound and an azo compound, and 100 parts by weight of the radical polymerizable compound. It is contained in an amount of 0.1 to 10 parts by weight, and the softening point of the insulating thermoplastic resin is lower than the exothermic peak temperature of the insulating adhesive component. At this time, the insulating thermoplastic resin, polyethylene and its copolymers, polystyrene and its copolymers, polymethyl methacrylate and its copolymers, polyvinyl chloride and its copolymers, polycarbonate and its copolymers, polypropylene and its air At least one selected from the group consisting of a copolymer, an acrylate ester rubber, a polyvinyl acetal, a polyvinyl butyral, an acrylonitrile-butadiene copolymer, a phenoxy resin, a thermoplastic epoxy resin and a polyurethane is preferable.

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Further, in the anisotropic conductive adhesive according to the present invention, the thickness of the coating layer made of an insulating thermoplastic resin formed on the surface of the conductive particles is 0.01 when considering the electrical connection between the insulating layer of the coating layer and the opposing electrode due to the softening of the coating layer. It is preferable that it is to 10 micrometers. The conductive particles are preferably formed by forming a thin metal layer on the surface of the polymer nucleus material, and the insulating adhesive component may further include a thermosetting resin and a curing agent for curing the thermosetting resin. It is preferable that the said polymerization initiator is an organic peroxide, and it is preferable that the said insulating adhesive component further contains a thermoplastic resin. The thermosetting resin is preferably contained in 20 to 200 parts by weight based on 100 parts by weight of the radical polymerizable compound. The weight ratio between the thermoplastic resin and the radically polymerizable compound contained in the insulating adhesive component is preferably 1: 9 to 9: 1.

The circuit connection method according to the present invention provided to achieve the above technical problem comprises the steps of: (a) interposing an anisotropic conductive adhesive provided according to the present invention as described above between substrates having circuit electrodes facing each other; (b) electrically connecting the opposing circuit electrodes by heating and pressing to remove the insulating thermoplastic resin coating on the surface of the conductive particles in contact with the opposing circuit electrodes; And (c) curing the insulating adhesive component to bond and fix the circuit electrodes.

The circuit connection structure according to the present invention, which is provided to achieve the above technical problem, includes an anisotropic conductive adhesive provided according to the present invention as described above between substrates having circuit electrodes opposed to each other. Is electrically connected.

 EMBODIMENT OF THE INVENTION Hereinafter, the anisotropic conductive adhesive of this invention, the circuit connection method and circuit connection structure using the same are demonstrated in detail.

The adhesive component of the anisotropic conductive adhesive according to the present invention is a component that firmly bonds and secures between substrates, and contains a radically polymerizable compound and a polymerization initiator. The low temperature rapid curing and preservation properties allow the exothermic peak temperature to be 80 ° C. to 120 ° C. Preference is given to using the phosphorus component.

A radically polymerizable compound can use oligomers etc. other than a monomer as a substance which has a functional group superposed | polymerized by a radical, It is also possible to use a monomer and an oligomer together. As the radical polymerizable compound, methyl acrylate, ethyl acrylate, bisphenol A ethylene glycol modified diacrylate, isocyanuric acid ethylene glycol modified diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene Glycol diacrylate, pentaerythritol triacrylate, trimetholpropane triacrylate, trimetholpropane propylene glycol triacrylate, trimethol propane ethylene glycol triacrylate, isocyanuric acid ethylene glycol modified triacrylate Acrylate or methacrylate compounds such as dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, dicyclopentenyl acrylate and tricyclodecanyl acrylate Can be. In particular, an acrylate-based or methacrylate-based compound having a dicyclopentenyl group and / or a tricyclodecanyl group and / or a triazine ring can be preferably used because of its high heat resistance. In addition, the radically polymerizable compounds include maleimide compounds, unsaturated polyesters, acrylic acid, vinyl acetate, acrylonitrile, methacrylonitrile, and the like, and these radically polymerizable compounds may be used alone or in combination.

The polymerization initiator performs a function of activating the radical polymerizable compound to form a polymer net structure or a polymer IPN structure, and the insulating adhesive component is cured according to the formation of such a crosslinked structure. As the polymerization initiator, a thermal initiator and / or a photopolymerization initiator may be used. The content of the polymerization initiator may be controlled depending on the type of the radical polymerizable compound and the reliability and workability of the desired circuit bonding process. It is preferable that it is 0.1-10 weight part with respect to a weight part.

The thermal polymerization initiator is a compound which decomposes by heating to generate free radicals, and examples thereof include peroxide compounds and azo compounds, and organic peroxides are particularly preferred. Organic peroxides have OO- bonds in the molecule and show activity by generating free radicals by heating, such as ketone peroxides, peroxy ketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, and peroxides. It is classified into oxycarbonate, peroxy ester, etc. Examples of ketone peroxides include cyclohexanone peroxide, methylcyclohexanone peroxide, and the like, and peroxy ketals include 1,1-bis (t-butylperoxycyclohexanone) and 1,1-bis ( (t-butyl peroxy 3,3,5 trimethylcyclohexanone) etc. are mentioned, As hydroperoxides, t-butyl hydroperoxide, a xmen hydroperoxide, etc. are mentioned, Dialkyl peroxides are mentioned. Examples of the diacyl peroxide include dichyl peroxide and di-t-butyl peroxide. Examples of the diacyl peroxide include lauroyl peroxide and benzoyl peroxide. Examples of the peroxydicarbonates include diisopropyl peroxide. And a dicarbonate, bis- (4-t-butylcyclohexyl) peroxydicarbonate, and the like. Examples of the peroxy esters include t-butylperoxybenzoate and t-butylperoxy (2-ethylhexanoate). , t-butylperoxyisopropylcarbonate, 1,1,3,3-tetrameth Butyl peroxy-2-ethyl hexanonate etc. In consideration of the balance of storage property, curability, and adhesiveness, it is more preferable to use peroxy ketals and peroxy esters. Examples of initiators include potassium persulfate and ammonium persulfate, and azo-based thermal initiators include azobis isobutylonitrile, 2-2'-azobis-2-methylbutylonitrile, and 4,4-azo. Bis-4-cyanobarrelic assido The above-mentioned thermal polymerization initiators may be used alone or in combination, and may be a radically polymerizable compound in a short time by appropriately selecting the desired connection temperature, connection time, and available time. Enables hardening of

Moreover, although a photoinitiator can be used instead of a thermal initiator, it can also be used together according to a radically polymerizable compound. Photoinitiators include carbonyl compounds, sulfur compounds and azo compounds.

In the anisotropic conductive adhesive according to the present invention, as the insulating adhesive component, in addition to the radical polymerizable material and the polymerization initiator, the use of a thermosetting resin and a curing agent such as an epoxy resin, an epoxy resin curing agent, a phenol resin and a phenol resin curing agent together improves adhesion and reliability. It is possible at the point of, and it is preferable to add 20-200 weight part based on 100 weight part of radically polymerizable compounds.

In addition, in the anisotropic conductive adhesive according to the present invention, it is preferable to include a thermoplastic resin in the insulating adhesive component, although the resin used in the conventional epoxy-based adhesive may be used, but is particularly compatible with radically polymerizable compounds for fast curing. It is good to use this good resin. Such thermoplastic resins include styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-butadiene saturated copolymer, styrene-isoprene saturated copolymer, styrene-ethylene-butene-styrene copolymer, acrylonitrile-butadiene copolymer, methyl Methacrylate polymer, acrylic rubber, urethane resin, phenoxy resin, polyester resin, polystyrene resin, polyvinyl butyral resin, polyvinyl formal, polyamide, polyimide, thermoplastic epoxy resin and phenol resin It is more preferable to use a urethane resin or a phenoxy resin from the viewpoint of improving the adhesive force. By using such a thermoplastic resin, an anisotropic conductive adhesive can be manufactured also in a film form. When it has a hydroxyl group, a carboxyl group, etc. at the terminal, since adhesive force improves, it is preferable. Such thermoplastic resins may be used alone or in combination. It is preferable that the weight ratio of a thermoplastic resin / radically polymerizable compound is 10/90-90/10, and, as for the compounding quantity of a thermoplastic resin, it is more preferable that it is 30/70-70/30.

In addition, a filler, a softener, an accelerator, a colorant, a flame retardant, a light stabilizer, a coupling agent, a polymerization inhibitor, and the like may be further added to the adhesive component of the anisotropic conductive adhesive of the present invention. For example, when the filler is added, the connection reliability can be improved, and when the coupling agent is added, the adhesion of the anisotropic conductive adhesive can be improved, and the adhesion strength, heat resistance, and moisture resistance can be improved to increase the connection reliability. Can be. As such a coupling agent, in particular, a silane coupling agent such as beta- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-methacryloxytrophiltrimethoxysilane Etc.

Insulating coating electroconductive particle which comprises the anisotropic conductive adhesive which concerns on this invention can be manufactured by the following method.

Any electroconductive particle to which an insulating thermoplastic resin is coat | covered can be used as long as it can electrically connect between circuits. For example, as shown in FIGS. 5A and 5B, metals such as nickel, iron, copper, aluminum, tin, zinc, chromium, cobalt, silver, and gold or metal oxides, solder, carbon, and the like Conductive particles 151 may be used as the conductive particles 151 by using conductive particles themselves or by forming the metal foil layer 154 on the surface of the nuclear material 153 such as glass, ceramic, or polymer through a thin layer formation method such as electroless plating. Can be. In particular, the conductive particles in which the metal foil layer is formed on the surface of the polymer nucleus material are deformed in the pressing direction in the pressing process, thereby increasing the contact area with the electrodes, thereby improving electrical connection reliability. The polymer nucleus material is various acrylates such as polyethylene, polypropylene, polystyrene, methyl methacrylate-styrene copolymer, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polycarbonate, and polymethyl methacrylate. , Polyvinyl butyral, polyvinyl formal, polyimide, polyamide, polyester, polyvinyl chloride, fluorine resin, urea resin, melamine resin, benzoguanamine resin, phenol-formalin resin, phenol resin, xylene resin, dia It may be made of various polymer resins such as reel phthalate resin, epoxy resin, polyisocyanate resin, phenoxy resin, silicone resin, and these resins may be used alone or in combination of two or more thereof. In addition, a polymer resin having a crosslinked structure may also be used by adding and reacting additives such as a crosslinking agent and a curing agent as necessary. Such nuclear materials are emulsified polymerization, suspension polymerization, non-aqueous dispersion polymerization, dispersion polymerization, interfacial polymerization, in-situ polymerization, liquid curing coating method, liquid drying method, melt dispersion cooling method, spray dry method, etc. It can manufacture. The conductive particles are preferably particles having a uniform particle diameter smaller than the distance between the circuit electrodes, but the particle diameter is preferably 0.1 to 50 µm, more preferably 1 to 20 µm, even more preferably 2 to 10 µm. to be.

The material of the coating layer formed on the surface of the electroconductive particle includes insulation and thermoplastic, and any number can be used as long as its softening point is lower than the exothermic peak temperature of the insulating adhesive component in which the insulating coating electroconductive particle is dispersed. Insulating thermoplastic resins include polyethylene and its copolymers, polystyrene and its copolymers, polymethylmethacrylate and its copolymers, polyvinylchloride and its copolymers, polycarbonates and their copolymers, polypropylene and their copolymers, acrylic acid Ester rubber, polyvinyl acetal, polyvinyl butyral, acrylonitrile-butadiene copolymer, phenoxy resin, thermoplastic epoxy resin, polyurethane, and the like, and these resins may be used alone or in combination of two or more thereof. It is obvious that these can be modified and used suitably.

As a method of forming a coating layer made of an insulating thermoplastic resin on the surface of the conductive particles, a known coating method such as an electrostatic coating method, a hot melt coating method, a solution coating method, or a dry-blend method may be used. When the metal foil layer coats an insulating thermoplastic resin on the electroconductive particle formed in the resin particle surface using the coating method, it demonstrates as an example. First, in order to facilitate bonding of the resin particle in which the metal foil layer was formed, and the insulating thermoplastic resin coat | covered on the surface, it surface-treats using a coupling agent, such as a silane coupling agent or a titanium type coupling agent. For example, when the metal foil layer uniformly disperses the conductive particles formed on the surface of the resin particles in the silane coupling agent solution, stirs for about 1 hour, and then dries, the conductive particles having the silane coupling agent surface-treated can be obtained. Subsequently, the surface-treated conductive particles are dissolved in the insulating thermoplastic resin solution to be coated and dispersed evenly. Then, the insulating thermoplastic resin solution in which the conductive particles are dispersed is added dropwise to an aqueous solution of a nonionic emulsifier and uniformly dispersed using a homogenizer, and then freeze-dried to obtain insulating coated conductive particles coated with the insulating thermoplastic resin.

Preferably the thickness of an insulating thermoplastic resin coating layer is 0.01-10 micrometers, More preferably, it is 0.05-5 micrometers, More preferably, it is 0.2-2 micrometers, Preferably it is 1 / 100-1 / 1 with respect to the particle diameter of electroconductive particle. 5, More preferably, it has a thickness of 1 / 50-1 / 10. If the thickness of the insulating thermoplastic resin coating layer is too thin, the insulation is degraded. If the thickness of the insulating thermoplastic resin layer is too thin, poor insulation may occur because the insulating coating layer in the pressing direction in contact with the circuit electrode is not removed even when heated and pressed.

It is preferable that content of an insulation coating electroconductive particle is 0.1-30 volume parts with respect to 100 volume parts of insulating adhesive components. As such, the reason why the insulating coated conductive particles can be used at a high concentration up to about 1/3 volume of the insulating adhesive component is that even when the conductive particles are aggregated, no conduction occurs between the conductive particles due to the insulating coating layer formed on the surface of the conductive particles. This is because there is no fear of a short circuit between adjacent circuits.

Hereinafter, the effect at the time of connecting a circuit using the anisotropic conductive adhesive of this invention is demonstrated.

Referring to FIG. 4, in the anisotropic conductive adhesive 130 of the present invention, a plurality of insulating coated conductive particles 150 having a coating layer 152 made of an insulating thermoplastic resin formed on the surface of the conductive particles 151 include an insulating adhesive component 140. The insulating thermoplastic resin constituting the coating layer 152 formed on the surface of the conductive particles 151 has a softening point lower than the exothermic peak temperature of the insulating adhesive component 140. Here, the exothermic peak temperature means the maximum exothermic temperature measured when the temperature of the adhesive component is increased at a rate of 10 ° C./min from the ambient temperature with a differential scanning calorimeter (DSC). In other words, the exothermic peak temperature is the temperature at which the reaction occurs most rapidly. The circuit connection process using the anisotropic conductive adhesive 130 is as follows.

First, the above-described anisotropic conductive adhesive 130 is interposed between the upper plate 10 and the lower plate 20 having the circuit electrodes 11 and 21 facing each other (FIG. 6).

Subsequently, when heating and pressing at a predetermined temperature and pressure, the insulating thermoplastic resin constituting the coating layer 152 is softened before the insulating adhesive component 140 is cured, and the coating layer in the pressing direction in contact with the circuit electrodes 11 and 21 is removed. The circuit electrodes 11 and 21 are electrically connected to each other via the conductive particles 151. On the other hand, since the coating layer not in the pressing direction is not detached from the surface of the conductive particles 151 even if it is softened, even if the insulating coated conductive particles 150 are agglomerated, insulation is maintained between adjacent electrodes, thereby preventing a short circuit. If the softening point of the insulating thermoplastic resin constituting the coating layer 152 formed on the surface of the conductive particles 151 is higher than the exothermic peak temperature of the insulating adhesive component 140, the insulating adhesive component 140 before the coating layer 152 is softened. Since this is first hardened, the insulation coating layer in the pressing direction in contact with the circuit electrodes 11 and 21 is not removed, resulting in poor conduction.

After that, the insulating adhesive component 140 is completely cured, and the upper and lower substrates 10 and 20 are firmly adhered and fixed, so that the electrical connection between the opposing circuit electrodes by the anisotropic conductive adhesive according to the present invention is electrically connected. A high circuit connection structure is formed (FIG. 7).

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

<Example 1>

Preparation of Insulation Coating Electroconductive Particles

Electroconductive particles consisting of metal-coated resin particles (Integral Chemical Company, trade name Micropearl AU205, 5.0 μm) were placed in a 5 wt% acetone solution of 3-Methacryloxypropyl trimethoxy Silane (Aldrich), uniformly dispersed, and dried to obtain surface-treated conductive particles. . Subsequently, 3 g of surface-treated conductive particles were added to a solution in which 3 g of polystyrene (Nova Chemical Company, STYROSUN 2158, softening point 96 ° C.) was dissolved in 15 g of normal hexane, and then 100 g of an aqueous solution containing a nonionic emulsifier (Srobitan monolaurate). The mixture was added homogeneously using a homogenizer while slowly added, and then lyophilized to obtain insulating coated conductive particles having a polystyrene insulating coating layer having a thickness of 0.7 µm.

Preparation of Anisotropic Conductive Adhesive

50 g of phenoxy resin (Inchem Co., PKHC, average molecular weight 45,000) was dissolved in a mixed solvent in which toluene (boiling point 110.6 ° C., SP value 8.90) / acetone (boiling point 56.1 ° C., SP value 10.0) was mixed at a weight ratio of 50/50. To prepare a solution having a solid content of 40%. Subsequently, 50 g of phenoxy resins in a solid weight ratio, 50 g of trihydroxyethylglycol dimethacrylate resin (a public corporation holding agent, trade name 80 MFA) which is a radically polymerizable compound, and t-butylperoxy-2-ethylhexano as a polymerization initiator were then used. An insulating adhesive component was prepared by blending it to 3 g of Nate (strength Atopinase, trade name Luperox 26), and the insulating coated conductive particles prepared by the method described above were blended in a ratio of 3 parts by volume to 100 parts by volume of the adhesive component. Dispersed evenly to prepare an anisotropic conductive adhesive. Then, the anisotropically conductive adhesive agent was apply | coated to the PET film which carried out the release process of the single side | surface of thickness of 50 micrometers using a coating apparatus, and it dried by hot air at 70 degreeC for 10 minutes, and obtained the anisotropically conductive adhesive film whose thickness of an adhesive bond layer is 35 micrometers. Here, the exothermic peak temperature of the insulating adhesive component was 107 ° C as a result of the measurement.

<Example 2>

50 g of phenoxy resin (Inchem Co., PKHC, average molecular weight 45,000) was dissolved in a mixed solvent in which toluene (boiling point 110.6 ° C., SP value 8.90) / acetone (boiling point 56.1 ° C., SP value 10.0) was mixed at a weight ratio of 50/50. To prepare a solution having a solid content of 40%. Subsequently, 50 g of phenoxy resins, 30 g of trihydroxyethyl glycol dimethacrylate resins (manufactured by Co., Ltd., trade name 80 MFA), and t-butylperoxy-2-ethylhexanoate (Century Atopinase, trade name looper) were used at a solid weight ratio. 1.8 g, 20 g of thermosetting phenolic resin (Kolon Emulsifier, trade name KRD-HM2) and 1 g of hardener (Hexamethylene tetramine, HMTA) were mixed to prepare an insulating adhesive component, and the insulating coated conductive particles of Example 1 were prepared therein. An anisotropic conductive adhesive was prepared by blending and dispersing evenly in a ratio of 3 parts by volume to 100 parts by volume of the adhesive component. Then, the anisotropically conductive adhesive agent was apply | coated to the PET film which carried out the release process of the single side | surface of thickness of 50 micrometers using a coating apparatus, and it dried by hot air at 70 degreeC for 10 minutes, and obtained the anisotropically conductive adhesive film whose thickness of an adhesive bond layer is 35 micrometers. Here, the exothermic peak temperature of the insulating adhesive component was 109 ° C as a result of the measurement.

Comparative Example 1

Polystyrene (Nova Chemical Co., Ltd.) whose softening point is 122 degreeC instead of the polystyrene of Example 1 whose softening point is 96 degreeC (Nova Chemical company, brand name STYROSUN 2158) as raw material resin of the insulating coating layer of insulation coating electroconductive particle. An anisotropic conductive adhesive film was prepared in the same manner as in Example 1 except that the trade name DYLARK 232) was used.

Between the flexible circuit boards (FPC) which have 500 copper circuits with a line width of 50 micrometers, a pitch of 100 micrometers, and a thickness of 18 micrometers 500, the anisotropic conductive adhesive films manufactured according to Examples 1-2 and Comparative Example 1 are interposed, respectively, The adhesive surface of the anisotropic conductive adhesive film was attached to the film, and then heated and pressed at 70 ° C. and 5 kg / cm 2 for 5 seconds to be temporarily connected over a width of 2 mm. The PET film was peeled off and connected to the other FPC to connect the circuit. It was. Subsequently, heat pressurization was performed at 160 degreeC and 30 kg / cm <2> for 10 second, and the circuit connection structure was completed.

Table 1 below shows the results of measuring the adhesion, connection resistance, and connection resistance reliability of the circuit connection structure thus prepared after being left for 1000 hours at 65 ° C and 95% relative humidity.

division Adhesive force (g / cm) Connection resistance (Ω) Connection resistance reliability (Ω) Example 1 815 1.0 4.0 Example 2 950 1.1 4.3 Comparative Example 1 812 24.0 N / A

Referring to Table 1, it can be seen that the circuit connection structure using the anisotropic conductive adhesives of Examples 1 and 2 according to the present invention has good adhesion, connection resistance, and connection resistance reliability.

On the other hand, the connection resistance of Comparative Example 1 was found to be high because the softening point (122 ° C.) of the polystyrene resin forming the insulating coating layer of the conductive particles was higher than the exothermic peak temperature (107 ° C.) of the insulating adhesive component. It is judged that the adhesive component was cured before this softening was sufficiently removed.

As described above, the anisotropic conductive adhesive of the present invention can be rapidly cured at low temperature, thereby greatly increasing the production efficiency. Even when electroconductive particle aggregates without a poor conduction, the short circuit of a circuit can be prevented and it is very useful for manufacture of a circuit connection structure.

Claims (14)

An insulating adhesive component containing a radically polymerizable compound and a polymerization initiator and having an exothermic peak temperature of 80 ° C to 120 ° C; And A coating layer made of an insulating thermoplastic resin is formed on the surface of the conductive particles, a plurality of insulating coated conductive particles dispersed in the insulating adhesive component in 0.1 to 30 parts by volume relative to 100 parts by volume of the insulating adhesive component; The radically polymerizable compound is at least one selected from the group consisting of an acrylate compound or a methacrylate compound, The polymerization initiator is at least one selected from the group consisting of a peroxide compound and an azo compound, it is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the radically polymerizable compound, The softening point of the insulating thermoplastic resin is lower than the heat generating peak temperature of the insulating adhesive component. The method of claim 1, The insulating thermoplastic resin is polyethylene and its copolymers, polystyrene and its copolymers, polymethyl methacrylate and its copolymers, polyvinyl chloride and its copolymers, polycarbonate and its copolymers, polypropylene and its copolymers, An anisotropic conductive adhesive, characterized in that at least one selected from the group consisting of acrylate ester rubber, polyvinyl acetal, polyvinyl butyral, acrylonitrile-butadiene copolymer, phenoxy resin, thermoplastic epoxy resin and polyurethane. The method of claim 1, The conductive particle is an anisotropic conductive adhesive, characterized in that the thin metal layer is formed on the surface of the polymer nucleus material. The method of claim 1, The insulating adhesive component further comprises a curing agent for curing the thermosetting resin and the thermosetting resin. The method of claim 1, The coating layer which consists of said insulating thermoplastic resins has an thickness of 0.01 micrometer-10 micrometers, The anisotropic conductive adhesive characterized by the above-mentioned. The method of claim 5, The conductive particle is an anisotropic conductive adhesive, characterized in that the thin metal layer is formed on the surface of the polymer nucleus material. The method of claim 5, The insulating adhesive component further comprises a curing agent for curing the thermosetting resin and the thermosetting resin. The method of claim 1, The peroxide compound selected as the polymerization initiator is an anisotropic conductive adhesive, characterized in that the organic peroxide. The method of claim 1, The insulating adhesive component further comprises a thermoplastic resin. The method of claim 9, The thermoplastic resin and radically polymerizable compound contained in the said insulating adhesive component have an weight ratio of 1: 9-9: 1, The anisotropic conductive adhesive characterized by the above-mentioned. (a) interposing an anisotropic conductive adhesive according to any one of claims 1 to 10 between substrates having circuit electrodes facing each other; (b) electrically connecting the opposing circuit electrodes by heating and pressing to remove the insulating thermoplastic resin coating on the surface of the conductive particles in contact with the opposing circuit electrodes; And (c) hardening the insulating adhesive component, thereby adhering and fixing the circuit electrodes. A circuit connection structure, wherein an anisotropic conductive adhesive according to any one of claims 1 to 10 is interposed between substrates having circuit electrodes opposing each other, and the circuit electrodes facing each other are electrically connected. delete delete

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