TWI398880B - Circuit connection material and circuit connection structure - Google Patents

Abstract

Disclosed is a circuit connection material which is interposed between opposing circuit electrodes so as to electrically connect opposing electrodes in the direction of pressure when pressure is applied to the circuit electrodes.  The circuit connection material comprises an adhesive component, first electroconductive particles having a surface at least partially covered with an insulating covering material, and second electroconductive particles having a surface at least partially covered with Ni, an alloy or oxide of Ni, or a metal having a Vickers hardness of not less than 300 Hv, the second electroconductive particles having protrusions.  The ratio of the number of first electroconductive particles to the number of second electroconductive particles (number of first electroconductive particles/number of second electroconductive particles) is 0.4 to 3.

Description

Circuit connection material and circuit connection structure

The present invention relates to a circuit connecting material and a circuit connecting structure.

A circuit connecting material that heats and presses the opposing circuit and electrically connects the electrodes in the pressurizing direction, for example, disperses the conductive particles in an anisotropic conductive adhesive of an epoxy-based adhesive or an acrylic adhesive. The film is widely used in electrical connection between a TCP (Tape Carrier Package) or a COF (Chip On Flex) on which a semiconductor that mainly drives a liquid crystal display (LCD) is mounted, and an LCD panel, or a TCP or COF, and a printed circuit board.

Moreover, recently, when the semiconductor is directly packaged face down on the LCD panel or the printed circuit board, the conventional wire bonding method can also be used for the flip chip package which is advantageous for thinning or narrow pitch connection. A square conductive adhesive film can also be used as a circuit connecting material (for example, refer to Patent Documents 1 to 4).

Further, in recent years, with the COF or micro-coil of the LCD module, when a connection of circuit connecting materials is used, a problem of short-circuiting between adjacent electrodes still exists. In the countermeasures, the insulating particles are dispersed in the adhesive component to prevent short-circuiting (for example, refer to Patent Documents 5 to 9).

Further, the substrate is adhered to a wiring member made of an insulating organic material or glass, or a wiring member including at least one selected from the group consisting of tantalum nitride, polyoxynitride resin, and polyimide resin on at least a part of the surface. Next The agent component contains a technique of polyfluorene oxide particles (for example, refer to Patent Document 10). In addition, in order to reduce the internal stress which is inferior to the thermal expansion coefficient after adhesion, there is a technique in which rubber particles are dispersed by an adhesive (for example, refer to Patent Document 11).

Further, as a method for preventing a short circuit between circuits, there is a technique of using conductive particles on an insulating coating film surface (for example, refer to Patent Documents 12 and 13).

Prior technical literature Patent literature

Patent Document 1: JP-A-59-120436

Patent Document 2: JP-A-60-191228

Patent Document 3: Japanese Patent Publication No. 01-251787

Patent Document 4: Japanese Patent Publication No. 07-090237

Patent Document 5: JP-A-51-020941

Patent Document 6: Japanese Patent Publication No. 03-029207

Patent Document 7: Japanese Patent Publication No. 04-174980

Patent Document 8: Patent No. 3048197

Patent Document 9: Patent No. 3477367

Patent Document 10: International Publication No. 01/014484

Patent Document 11: JP-A-2001-323249

Patent Document 12: Patent No. 2790009

Patent Document 13: JP-A-2001-195921

Summary of invention

However, in the conventional circuit connecting material, the conductive particles which are formed by the protrusion of the organic film formed on the edge portion of the glass which becomes the glass of the substrate are blocked or aggregated, or even if the organic film is not formed. In the substrate, the photoresist of the COF in the edge portion of the glass blocks the flow of the adhesive, causing the conductive particles to agglomerate, and the problem of short circuit still exists.

Further, recently, in order to reduce the cost of an electrode of a glass substrate, a manufacturer using an IZO (Zinc doped Indium Oxide) electrode instead of a conventional ITO (Tin doped Indium Oxide) electrode is increasing. Since the IZO electrode has a higher electric resistance value than the ITO electrode, when a circuit connecting material containing conductive particles covering the surface with a conventional insulating film is used, the connection resistance between the opposing circuit electrodes becomes high. .

The present invention has been made in view of the above problems in the prior art, and an object thereof is to provide a circuit connecting material which can prevent a short circuit caused by agglomeration of conductive particles at an edge portion of a glass substrate while using an IZO electrode. A good connection resistance can also be obtained; and a circuit connection structure is provided which is electrically connected to the first circuit electrode and the second circuit electrode which are disposed opposite each other.

In order to achieve the above object, the present invention provides a circuit connecting material, The invention relates to a circuit connecting material which is connected between the circuit electrodes of the opposite turns and which is pressed against the circuit electrode and electrically connected between the electrodes in the pressurizing direction, and is characterized in that: the adhesive component and at least a part of the surface are insulated. a first conductive particle covered by the covering body, and a second conductive particle coated with Ni or at least an alloy or oxide of the surface and having a protrusion; a ratio of the first conductive particle to the second conductive particle (The number of the first conductive particles / the number of the second conductive particles) is 0.4 to 3.

Furthermore, the present invention provides a circuit connecting material which is characterized in that a circuit connecting material is electrically pressed between electrodes of a pressing direction and a circuit electrode which is electrically connected between the electrodes of the pressing direction, and is characterized by containing : an adhesive component, at least a part of the surface of the first conductive particle covered with the insulating covering, and at least a part of the surface covered with a Vicker's hardness of 300 Hv or more of a metal, an alloy or a metal oxide and having a protrusion The second conductive particles; the number ratio of the first conductive particles to the second conductive particles (the number of the first conductive particles / the number of the second conductive particles) is 0.4 to 3.

According to such a circuit connecting material, it is possible to prevent a short circuit caused by aggregation of conductive particles at the edge portion of the glass substrate, and a good connection resistance can be obtained even when an IZO electrode is used. The inventors of the present invention have estimated the reason why such an effect can be obtained. In other words, it is considered that only the first conductive particles lack the resin exclusion between the substrate and the conductive particles, and a sufficient contact area cannot be obtained. However, by the presence of the second conductive particles, the substrate and the conductive particles are easily excluded. The resin is used to ensure a sufficient contact area and a good connection resistance.

In the circuit connecting material of the present invention, the volume ratio of the first conductive particles to the second conductive particles (the volume of the first conductive particles / the volume of the second conductive particles) is preferably 0.4 to 3, more preferably 0.45 to 2.5. The most suitable is 0.5~2.0. Thereby, the second conductive particles required to ensure a sufficient contact area between the substrate and the conductive particles can be obtained, and a better connection resistance can be obtained.

Further, in the second conductive particles of the circuit connecting material of the present invention, it is preferable that the height of the protrusions is 50 to 500 nm, and the distance between the protrusions adjacent to each other is 1000 nm or less. Thereby, the connection resistance between the opposing circuit electrodes can be more sufficiently reduced, and the rise of the connection resistance with time can be more sufficiently suppressed.

Further, in the first conductive particles of the circuit connecting material of the present invention, it is preferable to provide the insulating covering so that the coating ratio is 20 to 70%. Thereby, the insulation between the adjacent circuit electrodes can be sufficiently ensured, and the connection resistance between the opposing circuit electrodes can be more sufficiently reduced. Moreover, the rise of the connection resistance with time can be more sufficiently suppressed.

Further, in the circuit connecting material of the present invention, it is preferable that the first conductive particles are provided with conductive core particles and the insulating covering material containing a plurality of insulating particles provided on the surface of the core particles, and the insulating property. The ratio (D ₂ /D ₁ ) of the average particle diameter (D ₂ ) of the particles to the average particle diameter (D ₁ ) of the core particles is 1/10 or less. Thereby, the connection resistance between the opposing circuit electrodes can be more sufficiently reduced, and the rise of the connection resistance with time can be more sufficiently suppressed.

Further, in the circuit connecting material of the present invention, it is preferable that the first conductive particles are provided with the conductive core particles and the insulating coating layer containing an insulating layer of an organic polymer compound provided on the surface of the core particles. The ratio (T ₂ /D ₁ ) of the thickness (T ₂ ) of the insulating layer to the average particle diameter (D ₁ ) of the core particles is 1/10 or less. Thereby, the connection resistance between the opposing circuit electrodes can be more sufficiently reduced, and the rise of the connection resistance with time can be more sufficiently suppressed.

Further, in the circuit connecting material of the present invention, it is preferable that the first conductive particles and the second conductive particles have an average particle diameter of 2 to 6 μm. Thereby, the insulation between the adjacent circuit electrodes can be more sufficiently ensured, and the connection resistance between the opposing circuit electrodes can be more sufficiently reduced.

The present invention further provides a circuit connection structure, characterized in that a first circuit member having a first circuit electrode and a second circuit member having a second circuit electrode are used to make the first circuit electrode and the second circuit electrode Arranging in a facing manner, and the circuit connecting material of the present invention is disposed between the first circuit electrode and the second circuit electrode disposed opposite to each other, and the first circuit is disposed oppositely by pressurization heating The electrode is electrically connected to the second circuit electrode.

In such a circuit connection structure system, since the first circuit member and the second circuit member are connected by using the circuit connecting material of the present invention described above, occurrence of a short circuit between adjacent circuit electrodes can be sufficiently suppressed, and the opposing circuit electrodes can be sufficiently reduced. Connect the resistor.

Furthermore, the present invention provides the circuit connection structure described above, wherein at least one of the first circuit electrode and the second circuit electrode is an ITO electrode.

Further, the present invention provides the circuit connection structure described above, wherein at least one of the first circuit electrode and the second circuit electrode is an IZO electrode.

According to the present invention, it is possible to provide a short circuit between circuits without using a conventional circuit connecting material, and a good connection resistance can be obtained even when a high-resistance electrode such as an IZO electrode is used, and the connection reliability is also excellent. Circuit connection material and circuit connection structure.

Form for implementing the invention

Hereinafter, an appropriate embodiment of the present invention will be described in detail with reference to the drawings as needed.

The circuit connecting material of the present invention contains an adhesive component, first conductive particles, and second conductive particles. Further, in the present invention, the constituent material of the adhesive component-based circuit connecting material contains all of the materials other than the conductive particles.

The circuit connecting material of the present invention may contain an adhesive composed of (a) an epoxy resin and (b) a latent curing agent as an adhesive component.

(a) Epoxy resin can be a bisphenol type epoxy resin derived from epichlorohydrin and bisphenol A, bisphenol F and/or bisphenol AD, epichlorohydrin and phenol novolac or cresol novolac Derivative epoxy novolac resin, naphthalene epoxy resin having a naphthalene ring-containing skeleton, glycidylamine, glycidyl group A variety of epoxy compounds having two or more glycidyl groups in one molecule such as an ether, a biphenyl group or an alicyclic group. These may be used alone or in combination of two or more.

In order to prevent electron migration, such an epoxy resin is preferably a high-purity product in which impurity ions (Na ⁺ , Cl ^{- ,} etc.) or hydrolyzable chlorine are reduced to 300 ppm or less.

(b) The latent curing agent may, for example, be an imidazole-based compound, a hydrazine-based compound, a boron trifluoride-amine complex, a sulfonium salt, an amine sulfimine, a polyamine salt, or dicyanamide. These may be used alone or in combination of two or more. Further, these latent curing agents may be used by mixing a decomposition accelerator, an inhibitor, or the like. In addition, it is preferred that the latent curing agent is coated with a polyurethane material, a polyester-based polymer material, or the like to be microencapsulated, since the usable time can be extended.

Further, the circuit connecting material used in the present invention may contain (c) a curing agent which generates free radicals by heating or light, and an adhesive composed of (d) a radical polymerizable substance as an adhesive component.

(c) A curing agent that generates a free radical by heating or light (hereinafter, referred to as a "free radical generating agent" as the case), for example, heating or light decomposition of a peroxy compound or an azo compound Produce free radicals. The free radical generating agent is appropriately selected depending on the connection temperature, the connection time, the usable time, and the like, but from the viewpoint of high reactivity and usable time, the temperature at which the half life is 10 hours is 40° C. or more, and the half life is 1 minute. The organic peroxide has a temperature of 180 ° C or less.

(c) Blending of hardeners that generate free radicals by heating or light The amount is preferably from 0.05 to 10% by mass, more preferably from 0.1 to 5% by mass, based on the total amount of the solid content of the adhesive component.

(c) A hardener which generates free radicals by heating or light, and specific examples thereof include dinonyl peroxides, peroxydicarbonates, peroxyesters, peroxyketals, and dialkyl peroxides. Classes, hydroperoxides, etc. Among these, from the viewpoint of suppressing corrosion of the circuit electrode of the circuit member, it is preferably a peroxy ester, a dialkyl peroxide or a hydroperoxide, and further, from the viewpoint of obtaining high reactivity, It is preferably a peroxyester.

Examples of the dioxonium peroxide group include isobutyl peroxide, 2,4-dichlorobenzylidene peroxide, 3,5,5-trimethylhexyl peroxide, octyl peroxide, and lauric peroxide. Sulfhydryl, stearyl peroxide, amber sulfonate, benzamidine peroxide, benzoyl peroxide, and the like.

Examples of the peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, and di-2-. Ethoxymethoxyperoxydicarbonate, bis(2-ethylhexylperoxy)dicarbonate, dimethoxybutylperoxydicarbonate, bis(3-methyl-3-methoxyl) Butyl peroxy) dicarbonate and the like.

Examples of the peroxyesters include cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, and 1-cyclohexyl-1-methylethyl peroxide. Phthalate, tert-butyl peroxy neodecanoate, tert-butyl trimethyl ethoxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate 2,5-Dimethyl-2,5-bis(2-ethylhexylperoxy)hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, Third hexyl peroxide-2- Ethyl hexanoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy isobutyrate, 1,1-bis(t-butylperoxy)cyclohexane, Trihexylperoxyisopropyl monocarbonate, third hexylperoxy-3,5,5-trimethylhexanoate, third hexylperoxylaurate, 2,5-dimethyl-2,5 - bis(m-tolylperyl peroxide) hexane, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexyl monocarbonate, third hexylperoxybenzoate An acid ester, a third butyl peroxyacetate or the like.

The peroxy ketals may, for example, be 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, 2,2-double (Third butyl peroxidation) decane, and the like.

Examples of the dialkyl peroxides include α,α'-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, and 2,5-dimethyl-2,5-di (the Tributyl peroxy) hexane, tributyl cumyl peroxide, and the like.

Examples of the hydroperoxides include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

(c) The curing agent which generates free radicals by heating or light can be used singly or in combination of two or more kinds. Further, (c) a curing agent which generates free radicals by heating or light may be used by mixing a decomposition accelerator, an inhibitor or the like.

(d) The radically polymerizable substance is a substance having a functional group which is polymerized by a radical, and examples thereof include an acrylate, a methacrylate, and a maleimide compound.

Examples of the acrylate or methacrylate include urethane (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, and isopropyl (meth) acrylate. Isobutyl (meth) acrylate, ethylene glycol di(meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane Tris(meth)acrylate, tetramethylolmethanetetra(meth)acrylate, 2-hydroxy-1,3-bis(methyl)propenylpropanepropane, 2,2-bis[4-((A) Acryl-mercaptomethoxy)phenyl]propane, 2,2-bis[4-((meth)acryloylpolyethoxy)phenyl]propane, dicyclopentenyl (meth) acrylate , tricyclodecenyl (meth) acrylate, bis((meth) propylene methoxyethyl) trimer isocyanate, ε-caprolactone modified tris((meth) propylene oxiranyl) Trimeric isocyanate, tris((meth)acryloxyethyl)trimeric isocyanate, and the like.

In the present invention, one type or two or more types of such radically polymerizable substances may be used in combination.

The maleic imine compound is preferably one having at least two maleimine groups in the molecule, and examples thereof include 1-methyl-2,4-bismaleimide benzene and N,N'-. Phenylene-based bismaleimide, N,N'-p-phenylene bismaleimide, N,N'-m-tolyl-maleimide, N,N'-4,4- Biphenylene bismaleimide, N,N'-4,4-(3,3'-dimethyl-biphenylene) bismaleimide, N,N'-4,4 -(3,3'-dimethyldiphenylmethane) bismaleimide, N,N'-4,4-(3,3'-diethyldiphenylmethane) double malayan Amine, N, N'-4,4-diphenylmethane, bismaleimide, N,N'-4,4-diphenylpropane, bismaleimide, N,N'-4,4 -diphenyl ether bismaleimide, 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-maleimide phenoxy) Phenyl]decane, 4,4'-cyclohexylene-bis[1-(4-maleimidophenoxy)-2-cyclohexyl]benzene, 2,2-bis[4-(4 - Maleidanilide phenoxy)phenyl]hexafluoropropane, and the like. These may be used alone or in combination of two or more, or may be used in combination with an allyl ester compound such as allyl phenol, allyl phenyl ether or allyl benzoate.

Further, in the present invention, it is preferable that the circuit member before the hardened circuit connecting material can be temporarily fixed, and it is preferable to contain a radical polymerizable substance having a viscosity of at least 100 ° C at 100 ° C to 1,000,000 mPa ‧ s, preferably It is a radical polymerizable substance having a viscosity (25 ° C) of 100,000 to 500,000 mPa·s. The viscosity of the radically polymerizable substance was measured using a commercially available E-type viscometer.

(c) Among the radically polymerizable substances, from the viewpoint of adhesion, urethane acrylate or urethane methacrylate is preferable. Moreover, in order to improve heat resistance, it is preferable to use a Tg of a polymer which is crosslinked with the above-mentioned organic peroxide to form a radical polymerizable substance of 100 ° C or more. As such a radically polymerizable substance, those having a dicyclopentenyl group, a tricyclodecenyl group, and/or a triazine ring can be used. In particular, a radically polymerizable substance having a tricyclodecenyl group and/or a triazine ring is suitably used.

Further, a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be suitably used as the binder component.

Further, the solid content of the adhesive component is used as a reference (100) When the amount of the radical polymerizable substance having a phosphate structure is 0.1 to 10% by mass, the adhesion strength of the surface of the inorganic material such as metal is improved, so that it is preferably used in an amount of 0.5 to 5% by mass.

The radically polymerizable substance having a phosphate structure can be obtained by forming a reactant of phosphoric anhydride and 2-hydroxy (meth) acrylate. Specific examples thereof include 2-methacryloxyethyl acid phosphate, 2-propylene oxirane acid phosphate, and the like. These may be used alone or in combination of two or more.

The circuit connecting material of the present invention comprises: a first conductive particle coated on at least a part of the surface by the insulating covering, at least a part of the surface is made of Ni or an alloy or oxide thereof, or a metal having a Vicker's hardness of 300 Hv or more At least two types of conductive particles coated with an alloy or a metal oxide and having protruding second conductive particles. Moreover, the number ratio of the first conductive particles to the second conductive particles (the number of the first conductive particles / the number of the second conductive particles) included in the circuit connecting material is 0.4 to 3. Hereinafter, the first conductive particles and the second conductive particles will be described with reference to the drawings.

First, the first conductive particles in which at least a part of the surface is covered with the insulating covering will be described. It is preferable that the first conductive particles are provided with conductive core particles and an insulating coating provided on the surface of the core particles. It is preferable that the first conductive particles are provided with an insulating coating so that the coverage ratio is in the range of 20 to 70%. Here, the above coverage ratio is defined by the following formula (1).

The coverage of the first conductive particles is preferably from 20 to 70%, more preferably from 20 to 60%. When the coverage of the first conductive particles is 20 to 70%, the conductive material may be contained in the circuit connecting material in an amount sufficient to obtain a sufficiently low initial resistance value. This is accompanied by an increase in the content of the conductive particles, and even if the agglomerates of the conductive particles are generated, the electrical connection between the adjacent circuit electrodes can be sufficiently prevented by the insulating coating provided on the respective conductive particles.

Further, when the conductive particles coated with the insulating covering on the entire surface are used, an insulating coating is present between the core particles and the surface of the circuit electrode, and the electrical insulating path is interposed between the insulating coatings. However, the first conductive particles having a coverage ratio of 20 to 70% are partially covered with insulation, so that the insulating covering body interposed in the electrical path can be sufficiently reduced. Therefore, the influence of the insulating covering existing in the path can be sufficiently suppressed. Therefore, compared with the conductive particles coated with the insulating covering on the entire surface, the initial resistance value of the connection portion can be lowered, and the increase in the resistance value with time can be more reliably suppressed.

The insulating coating system of the first conductive particles may be composed of a plurality of insulating particles provided on the surface of the core particles. In this case, the ratio of the average particle diameter of the insulating particles (D ₂₎ of the core particles with an average particle diameter (D ₁₎ of the (D ₂ / D ₁₎ should be 1/10 or less. When the ratio is 1/10 or less, both the low resistance value of the connection portion and the suppression of the increase in the resistance value with time can be more surely achieved.

Moreover, the insulating coating system provided in the first conductive particles is provided on the surface of the nuclear power particles and is composed of an insulating layer containing an organic polymer compound. At this time, the ratio (T ₂ /D ₁ ) of the thickness (T ₂ ) of the insulating layer to the average particle diameter (D ₁ ) of the core particles is preferably 1/10 or less. When the ratio is 1/10 or less, both the low resistance value of the connection portion and the suppression of the increase in the resistance value with time can be more surely achieved.

Fig. 1 is a schematic cross-sectional view showing an appropriate form of a first conductive particle. The first conductive particles 10A shown in FIG. 1 are composed of core particles 1 having conductivity and a plurality of insulating particles 2A provided on the surface of the core particles 1.

The core particles 1 are composed of the base material particles 1a constituting the center portion and the conductive layer 1b on the surface of the base material particles 1a.

The material of the substrate particles 1a may, for example, be glass, ceramics or an organic polymer compound. Among these materials, those which are deformed by heating and/or pressurization (for example, an organic polymer compound) are preferred. When the substrate particle 1a is deformed, when the conductive particle 10A is pressed by the circuit electrode, the area of the circuit electrode increases. Further, the unevenness of the surface of the circuit electrode can be absorbed. Therefore, the connection reliability between the circuit electrodes is improved.

From such a viewpoint, as a material constituting the substrate particle 1a, for example, an acrylic resin, a styrene resin, a benzoguanamine resin, a polyoxyxylene resin, a polybutadiene resin or a copolymer thereof may be used. Make these crosslinkers. The substrate particles 1a may be of the same or different types of materials, and may be used by mixing one or more kinds of materials of the same particle alone or in combination.

The average particle diameter of the substrate particles 1a can be appropriately designed depending on the use, etc., but is preferably 0.5 to 20 μm, more preferably 1 to 10 μm, and most preferably 2 to 5 μm. When conductive particles are produced using substrate particles having an average particle diameter of less than 0.5 μm, secondary aggregation of particles occurs, and insulation between adjacent circuit electrodes tends to be insufficient, and when substrate particles larger than 20 μm are used, When the conductive particles are produced, the insulation between the adjacent circuit electrodes due to their size tends to be insufficient.

The conductive layer 1b is a layer made of a conductive material provided to cover the surface of the substrate particles 1a. From the viewpoint of sufficiently ensuring conductivity, the conductive layer 1b is preferably the entire surface of the coated substrate particles 1a.

The material of the conductive layer 1b may, for example, be gold, silver, platinum, nickel, copper, an alloy thereof, an alloy containing tin or the like, and a non-metal having conductivity such as carbon. Since the base material particles 1a can be coated by electroless plating, the material of the conductive layer 1b is preferably metal. Further, in order to obtain a sufficient usable time, it is more preferably gold, silver, platinum or the like, and it is most preferably gold. Further, these may be used alone or in combination of two or more.

The thickness of the conductive layer 1b can be appropriately designed according to the material or use used therein, but is preferably 50 to 200 nm, more preferably 80 to 150 nm. If the thickness is less than 50 nm, there is a tendency that a sufficiently low resistance value of the connection portion cannot be obtained. Further, the conductive layer 1b having a thickness of more than 200 mm tends to have a low manufacturing efficiency.

The conductive layer 1b may be composed of one layer or two or more layers. Even in the case of any one, the surface layer of the core particle 1 is preferably gold, silver, platinum, palladium or an alloy thereof from the viewpoint of preservability of the circuit connecting material manufactured using the substrate. The composition is more preferably made of gold. When the conductive layer 1b is made of a layer composed of gold, silver, platinum, palladium or the like (hereinafter referred to as "metal such as gold"), the thickness of the connecting portion is preferably sufficiently low to obtain a resistance value of 10. ~200nm.

Further, when the conductive layer 1b is composed of two or more layers, the outermost layer of the conductive layer 1b is preferably made of a metal such as gold, but the layer between the outermost layer and the substrate particles 1a may contain, for example, nickel or copper. Tin or a metal layer of these alloys. In this case, the thickness of the metal layer composed of a metal such as gold constituting the outermost layer of the conductive layer 1b is preferably 30 to 200 nm from the viewpoint of storage stability of the adhesive component.

Nickel, copper, tin or these alloys sometimes produce free radicals by redox. Therefore, when the thickness of the outermost layer formed of a metal such as gold is less than 30 nm, it is difficult to sufficiently prevent the influence of free radicals when used in combination with a radical polymerizable adhesive component.

The method of forming the conductive layer 1b on the surface of the substrate particle 1a is, for example, an electroless plating treatment or a physical coating treatment. From the viewpoint of easiness of formation of the conductive layer 1b, it is preferable that the conductive layer 1b made of a metal is formed on the surface of the substrate particle 1a by electroless plating treatment.

The insulating particles 2A are made of an insulating material such as cerium oxide, glass, ceramics, or the like, or an organic polymer compound. The organic polymer compound is preferably one having thermal softening properties.

Suitable materials for the insulating particles are polyethylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer, polyester, polyamine, polyamine Acid ester, polystyrene , styrene-divinylbenzene copolymer, styrene-isobutylene copolymer, styrene-butadiene copolymer, styrene-(meth)acrylate copolymer, ethylene-propylene copolymer, (meth)acrylic acid Ester rubber, styrene-ethylene-butene copolymer, phenoxy resin, solid epoxy resin, and the like. These may be used alone or in combination of two or more. Further, from the viewpoint of the degree of dispersion of the particle size distribution, solvent resistance and heat resistance, a styrene-(meth)acrylate copolymer is particularly preferable. The method for producing the insulating particles 2A may, for example, be a seed polymerization method or the like.

The softening point of the organic polymer compound constituting the insulating particles 2A is preferably equal to or higher than the heating temperature when the circuit members are connected to each other. If the softening point does not reach the heating temperature at the time of connection, the insulating particles 2A are excessively deformed due to the connection, and there is a tendency that a good electrical connection cannot be obtained.

The degree of crosslinking of the organic polymer compound constituting the insulating particles 2A is preferably from 5 to 20%, more preferably from 5 to 15%, most preferably from 8 to 13%. The organic polymer compound having a degree of crosslinking within the above range is superior to both of the organic polymer compounds outside the range, and has excellent connection reliability and insulating properties. Therefore, if the degree of crosslinking is less than 5%, the insulation between the adjacent electrode circuits tends to be insufficient. Further, when the degree of crosslinking exceeds 20%, it is difficult to achieve both of the initial resistance value at which the connection portion is sufficiently low and the suppression of the increase in the resistance value with time.

The degree of crosslinking of the organic polymer compound can be adjusted by the composition ratio of the crosslinkable monomer to the non-crosslinkable monomer. The degree of crosslinking referred to in the present invention means a theoretically calculated value obtained by the composition ratio (feeding mass ratio) of a crosslinkable monomer and a non-crosslinkable monomer. That is, synthetic organic polymer compounds sometimes The feed quality of the blended crosslinkable monomer is a value calculated by dividing the feed ratio by the total of the crosslinkable monomer and the non-crosslinkable monomer.

The gel fraction of the organic polymer compound constituting the insulating particles 2A is preferably 90% or more, and more preferably 95% or more. When the gel fraction is less than 90% and the conductive particles 10A are dispersed in the adhesive component to form a circuit connecting material, the insulation resistance of the adhesive component tends to decrease with time.

Here, the gel fraction is an index indicating the resistance of the organic polymer compound to the solvent, and the measurement method will be described below. The mass (mass A) of the organic polymer compound (measured sample) for which the gel fraction was to be measured was measured. The sample to be measured is stored in a container, and the solvent is placed. The sample to be measured was stirred in a solvent at a temperature of 23 ° C for 24 hours, and immersed. Thereafter, the solvent was removed by volatilization or the like, and the mass (mass B) of the sample to be measured after the stirring and immersion was measured. The gel fraction (%) is a value calculated by the following formula.

Gel fraction (%) = (mass B / mass A) × 100

The solvent used for the measurement of the gel fraction (%) was toluene. Further, in the preparation of the solution of the circuit connecting material, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone or tetrahydrofuran can be generally used. The preparation of the solution of the circuit-connecting material may be used alone or in combination of two or more kinds.

The average particle diameter of the insulating particles 2A can be appropriately designed depending on the use, etc., but it is preferably 50 to 500 nm, more preferably 50 to 400 nm, and most preferably 100~300nm. When the average particle diameter is less than 50 nm, the insulation between the adjacent circuits tends to be insufficient. When the average particle diameter is less than 500 nm, it is difficult to achieve an initial resistance value at which the connection portion is sufficiently low and the resistance value is suppressed from increasing with time. The tendency of the person.

The insulating particles 2A are preferably formed on the surface of the core particle 1 so that the coating ratio defined by the above formula (1) is 20 to 70%. From the viewpoint of more reliably obtaining the effect of insulation and conduction, the coverage rate is preferably 20 to 60%, more preferably 25 to 60%, and most preferably 28 to 55%. When the coverage is less than 20%, the insulation between the adjacent circuit electrodes tends to be insufficient, and if it exceeds 70%, it is difficult to achieve an initial resistance value at which the connection portion is sufficiently low and the resistance value is suppressed from increasing with time. The tendency of both. Further, the plurality of insulating particles 2A covering the core particles 1 are preferably on the surface of the core particles 1, and are preferably sufficiently dispersed.

The coverage ratio in the present invention can be obtained by observation with a scanning electron microscope (magnification: 8000 times), and is based on the following measurement values. In other words, the coverage ratio is a value calculated based on the respective average particle diameters of the core particles and the insulating particles and the number of insulating particles attached to one of the core particles. 50 particles were arbitrarily selected and measured as described above, and the average value was calculated.

The average particle diameter of the core particles 1 was measured as follows. That is, one of the core particles was arbitrarily selected, and the maximum diameter and the minimum diameter were measured by observation with a scanning electron microscope. The square root of the product of the largest diameter and the minimum diameter is taken as the particle diameter of the particles. The particle size was measured as described above for 50 particles arbitrarily selected, and the average value thereof was used as the average particle diameter (D ₁ ) of the core particle 1. In the same manner as in the above, the average particle diameter of the insulating particles 2A was measured for 50 particles of any of the insulating particles, and the average value thereof was defined as the average particle diameter (D ₂ ) of the core particles 2A.

The number of insulating particles included in one conductive particle was measured as follows. That is, one of the conductive particles of the insulating particles 2A which is partially covered with a plurality of surfaces is arbitrarily selected. Then, photography was carried out by a scanning electron microscope to calculate the number of insulating particles attached to the surface of the observable core particles. Thereby, the count obtained was doubled, and the number of insulating particles adhering to one core particle was calculated. The number of the insulating particles was measured by 50 arbitrarily selected conductive particles, and the average value was used as the number of insulating particles included in one conductive particle.

The total surface area of the core particles means the surface area of the sphere having the diameter (D ₁ ) described above. In addition, the area of the portion covered with the insulating coating on the surface of the core particle is obtained by multiplying the value of the area of the circle having the diameter of (D ₂ ) by one of the number of insulating particles included in the conductive particle. value.

The ratio of the insulating particles 2A of the average particle diameter (D ₂₎ with an average particle diameter of the core particles ₁ (D 1) of the (D ₂ / D ₁₎ should be 1/10 or less, 1/15 or less is more desirable. Further, the lower limit of the ratio (D ₂ /D ₁ ) is preferably 1/20. When D ₂ /D ₁ exceeds 1/10, it is difficult to achieve both of the initial resistance value at which the connection portion is sufficiently low and the suppression of the resistance value with time. In addition, if it is less than 1/20, the insulation between adjacent circuits tends to be insufficient.

Moreover, the insulating coating system formed on the surface of the core particle 1 is not limited to a spherical shape like the insulating particle 2A. Insulation coating system can also be used An insulating layer made of the same material as the insulating particles 2A. For example, the first conductive particles 10B shown in FIG. 2 include an insulating layer 2B partially provided on the surface of the particles 1.

The insulating layer 2B is preferably formed on the surface of the core particle 1 so that the coverage ratio is 20 to 70%. From the viewpoint of more reliably obtaining the effects of the present invention, the coverage ratio is preferably from 20 to 60%, more preferably from 25 to 60%, most preferably from 28 to 55%. When the coverage is less than 20%, the insulation between the adjacent circuit electrodes tends to be insufficient, and if it exceeds 70%, it is difficult to achieve an initial resistance value at which the connection portion is sufficiently low and the resistance value is suppressed from increasing with time. The tendency of both. Moreover, each of the covering regions of the insulating particles 2B covering the core particles 1 is on the surface of the core particle 1, and is preferably sufficiently dispersed. Each covered area can also be isolated or continuous.

The ratio (T ₂ /D ₁ ) of the thickness (T ₂ ) of the insulating layer 2B to the average particle diameter (D ₁ ) of the core particles 1 is preferably 1/10 or less, more preferably 1/15 or less. Further, the lower limit of the ratio (T ₂ /D ₁ ) is preferably 1/20. When T ₂ /D ₁ exceeds 1110, it is difficult to achieve both of the initial resistance value at which the connection portion is sufficiently low and the suppression of the increase in the resistance value with time. In addition, if it is less than 1/20, the insulation between adjacent circuits tends to be insufficient.

The coverage ratio when the insulating coating is composed of the insulating layer 2B can be calculated in the following order. In other words, 50 randomly selected conductive particles are imaged by a scanning electron microscope, and the measured values of the area of the insulating layer adhering to the surface of the observable core particle are added and averaged.

Further, regarding the thickness (T ₂ ) of the insulating layer 2B, 50 pieces of arbitrarily selected conductive particles are respectively imaged by a scanning electron microscope, and the measured values of the thickness of the insulating layer 2B on the surface of each conductive particle are added. Average to get.

A method of forming an insulating coating (insulating particle 2A or insulating layer 2B) on the surface of the core particle 1 may be a known method, and for example, a wet method using a chemical change by an organic solvent or a dispersing agent may be used. And a dry method that utilizes physicochemical changes produced by mechanical energy. For example, a spray method, a high-speed stirring method, a spray drying method, or the like can be given.

In order to obtain the effect of the present invention more reliably, it is preferable that the plurality of insulating particles 2A having a very uniform particle diameter are provided on the surface of the core particle 1 to constitute an insulating coating. Further, rather than a wet method in which it is difficult to completely remove a solvent or a dispersant, it is preferable to use a dry method in which no solvent is used.

A device for forming an insulating coating on the surface of the core particle 1 in a dry manner, for example, a Mechanomill (trade name, manufactured by Deshou Works Co., Ltd.), a Hybridizer (manufactured by Nara Machinery Co., Ltd., trade name: NHS series) Wait. However, when the insulating coating is formed on the surface of the core particle 1, the surface of the core particle 1 is modified to an appropriate state. Therefore, a Hybridizer is preferably used. According to this apparatus, the insulating particles 2A having a very uniform particle diameter can be formed on the surface of the core particle 1 by precisely coating the particles.

The control of the shape of the insulating covering can be carried out, for example, by adjusting the conditions of the coating treatment. The conditions of the coating treatment are, for example, temperature and rotational speed. Further, the average particle diameter of the insulating particles 2A or the thickness of the insulating layer 2B can be adjusted by adjusting the conditions of the coating treatment or the ratio of the core particles 1 and the organic polymer compound (material of the insulating covering) supplied to the treatment. Come true Shi.

The temperature of the coating treatment (dry mode) is preferably 30 to 90 ° C, more preferably 50 to 70 ° C.

Further, the rotation speed of the coating treatment (dry method) is preferably 6,000 to 20,000/min, more preferably 10,000 to 17,000/min.

Although the appropriate form of the first conductive particles to be subjected to the insulating coating treatment has been described above, the first conductive particles of the present invention are not limited to the above-described ones. The first conductive particles of the present invention can be variously modified without departing from the gist thereof. For example, in the above embodiment, the core particles 1 composed of the substrate particles 1a and the conductive layer 1b are exemplified, but the core particles may be made of a conductive material (for example, the same material as the conductive layer 1b). The constituents. Further, particles composed of a hot molten metal may be used as the core particles. At this time, the core particles can be sufficiently deformed by heating and pressurization.

Further, the first conductive particles may be such that the insulating particles 2A and the insulating layer 2B are provided on the surface of the core particle 1 in the insulating coating.

Next, the description will be made regarding the second conductive particles, at least a part of which is covered with Ni or an alloy or oxide thereof, or a metal, alloy or metal oxide having a Vicker's hardness of 300 Hv or more, and has protrusions.

3(a) and 3(b) are cross-sectional views showing a suitable one of the second conductive particles. As shown in FIG. 3(a), the second conductive particles 20A are composed of a core body 21 composed of an organic polymer compound and a metal 22 formed on the surface of the core body 21. The core body 21 is a core portion 21a, It is constituted by a projection 21b formed on the surface of the core portion 21a. The metal layer 22 has a plurality of protrusions 14 on its surface side.

The organic polymer compound constituting the core portion 21a of the core body 21 may, for example, be an acrylic resin, a styrene resin, a benzoguanamine resin, a polyoxyl resin, a polybutadiene resin or a copolymer thereof, or may be used. Crosslink these people.

The organic polymer compound constituting the protrusion portion 21b may be the same as or different from the organic polymer compound constituting the core portion 21a. Further, the average diameter of the projections 21b is preferably 50 to 500 nm.

The core body 21 can be formed by adsorbing a plurality of protrusions 21b having a smaller diameter than the core portion 21a due to the surface of the core portion 21a.

The material of the metal layer 22 is Ni, or an alloy or oxide thereof, or a metal, alloy or metal oxide having a Vicker's hardness of 300 Hv or more. Examples of the metal, alloy or metal oxide of Vicker's hardness of 300 Hv or more include alloys and oxides of Ni, Pd, Rh, and the like. The material of the metal layer 22 among these is preferably Ni or an alloy or oxide thereof, more preferably Ni, from the viewpoint of versatility.

The Vicker's hardness of the metal, alloy or metal oxide which is the material of the metal layer 22 is 300 Hv or more, but from the viewpoint of resin exclusion and deformability, it is preferably 300 to 800 Hv, more preferably 300 to 600 Hv. .

The metal layer 22 can be formed on the surface of the core body 21 by, for example, electroless plating.

In addition, nickel alloys are various depending on the additives formulated in the plating bath. . Further known nickel alloys are, for example, nickel-phosphorus, nickel-boron or the like.

The thickness of the metal layer 22 (thickness of plating) is preferably 50 to 170 nm, more preferably 50 to 150 nm. When the thickness of the metal layer 22 is in such a range, the connection resistance between the circuit electrodes can be made better. When the thickness of the metal layer 22 is less than 50 nm, the connection resistance tends to increase due to defects such as plating, and when it exceeds 170 nm, condensation occurs between the conductive particles, and a short circuit occurs between adjacent circuit electrodes.

The height (H) of the projections 14 of the conductive particles 20A is preferably 50 to 500 nm, more preferably 75 to 300 nm. When the height of the protrusions is less than 50 nm, the connection resistance tends to be high after the high-temperature and high-humidity treatment. When the thickness exceeds 500 nm, the contact area with the circuit electrodes of the conductive particles is small, so that the connection resistance tends to be high.

The distance (S) between the adjacent projections 14 is preferably 1000 nm or less, more preferably 500 nm or less. When the distance between the protrusions 14 exceeds 1000 nm, the contact area between the conductive particles and the circuit electrode becomes small due to the unevenness of the protrusions, and the connection resistance tends to be high. Further, the distance (S) between the adjacent protrusions 14 is preferably 50 nm or more from the viewpoint that the conductive particles and the circuit electrode do not enter the adhesive component and the conductive particles are sufficiently in contact with the circuit electrode. Further, the height (H) of the protruding portion 14 of the conductive particle 20A and the distance (S) between the adjacent protruding portions 14 can be measured by an electron microscope.

Further, the second conductive particles are as shown in Fig. 3(b), and the core body 21 may be constituted only by the core portion 21a. The second conductive particle 20B is a surface of the metal plated core body 21, and a metal layer is formed on the surface of the core body 21. 22 to get. However, when the protrusions 14 are metal plated, the plating conditions are changed to change the thickness of the metal layer 22 to be formed on the metal layer 22. Further, the plating conditions are changed, for example, in the plating solution used first, and the plating solution having a higher concentration than the plating solution is formed so that the plating solution concentration is not uniform.

Further, the second conductive particles may be coated with Ni, an alloy or an oxide thereof, or a metal, alloy or metal oxide having a Vicker's hardness of 300 Hv or more, in insulating particles such as non-conductive glass, ceramics, and plastic. By. The second conductive particles are those in which the conductive particles are coated with the insulating particles, and the outermost layer is Ni, and the insulating particles that are the core are plastic, or the second conductive particles are hot-melted metal particles, which are caused by heat and pressure. The deformability is improved because the connection area with the circuit electrodes at the time of connection increases and the reliability is improved.

In the circuit connecting material, the total amount of the first and second conductive particles is preferably used in an amount of 0.1 to 30 parts by volume based on 100 parts by volume of the adhesive component. In order to more sufficiently prevent the short circuit of the adjacent circuit generated by the first and second conductive particles, the compounding amount is preferably 0.1 to 10 parts by volume.

Further, the average particle diameter of the first and second conductive particles is preferably 1 to 10 μm, more preferably 2, from the viewpoint that the short circuit between adjacent electrodes is smaller than the height of the electrode of the connected circuit. ~8μm, most preferably 2~6μm. Further, since the average particle diameter of the first conductive particles is smaller than the average particle diameter of the second conductive particles, the effect of further reducing the connection resistance between the opposing circuit electrodes can be improved, which is preferable. Moreover, the average particle diameter of the first conductive particles is larger than the average particle diameter of the second conductive particles, so that the insulation between the adjacent circuit electrodes can be sufficiently confirmed. Guarantee, so good. In particular, it is considered that the conductive particles coated with the insulating coating on the entire surface or the conductive particles having a coverage of more than 70% have a large effect. In addition, when the conductive particles having a coverage of 20% to 70% or the insulating fine particles are provided on the surface of each of the conductive particles, the size of the insulating fine particles or the coverage ratio tends to change, so it is preferable to appropriately adjust . These can be selected, for example, according to the characteristics required for the circuit connecting material of the present invention which differs in use.

Further, the first and second conductive particles are preferably used as appropriate from a 10% compression modulus (K value) of 100 to 1000 kgf/mm ² .

Here, the average particle diameter of the second conductive particles was also measured as follows. That is, one conductive particle was arbitrarily selected, and the maximum value and the minimum value were measured by observation with a scanning electron microscope. The square root of the product of the maximum and minimum values is taken as the particle diameter of the particles. For 50 arbitrarily selected conductive particles, the measurement was carried out as follows, and the average value thereof was used as the average particle diameter of the conductive particles.

In the above, it is explained that at least a part of the surface is coated with Ni or an alloy or an oxide thereof, or a metal, an alloy or a metal oxide having a Vicker's hardness of 300 Hv or more, and having a protruding second conductive particle. The form, but the second conductive particles in the present invention are not limited to the above-described form.

The number of the first and second conductive particles in the circuit connecting material of the present invention is such that the resin component in the adhesive component forming the circuit connecting material is dissolved in a soluble solvent, and the excess solvent is removed from the obtained insoluble component. After the component or the like, it can be confirmed by observation with a scanning electron microscope.

The solvent which can dissolve the resin component is, for example, MEK (methyl ethyl ketone), toluene or the like, but is not limited to such a solvent.

100 or more kinds of conductive particles existing in the obtained insoluble component were observed, and the ratio of the number of the first conductive particles to the second conductive particles (the number of the first conductive particles / the number of the second conductive particles) was measured. In the circuit connecting material of the present invention, the number ratio (the number of the first conductive particles / the number of the second conductive particles) must be 0.4 to 3, more preferably 0.45 to 2.5, and most preferably 0.5 to 2.0.

In the present invention, the volume of the conductive particles in the circuit connecting material can be obtained by converting the average particle diameter of the conductive particles contained in the circuit connecting material and the number of conductive particles per unit area into a volume ratio. a volume ratio of the conductive particles to the second conductive particles (volume of the first conductive particles / volume of the second conductive particles). In the circuit connecting material of the present invention, the volume ratio (volume of the first conductive particles / volume of the second conductive particles) is preferably 0.4 to 3, more preferably 0.45 to 2.5, and most preferably 0.5 to 2.0.

The definition of the volume of the conductive particles is such that the ratio of the volume of the entire conductive particles occupied by the protrusions or the insulating layer is small. Therefore, in the measurement of the volume of the conductive particles in the invention of the present invention, the insulating particles 2A and the insulating layer 2B are used. The protrusions 14 are not calculated.

Further, the circuit connecting material of the present invention may further contain conductive particles other than the first conductive particles and the second conductive particles. The content ratio of the other conductive particles is preferably 50% or less, more preferably 30% or less, and particularly preferably 20% or less, based on the total number of the first conductive particles and the second conductive particles.

The other conductive particles are not particularly limited, but may, for example, be Au or Ag. Metal particles such as Ni, Cu, and solder, or carbon. Further, in the other conductive particles, the particles which become the core are coated with one or two or more layers, or the outermost layer may be electrically conductive. In this case, one or two or more kinds of a transition metal such as Ni or Cu or a noble metal such as Au, Ag or a platinum group metal may be used in the outermost layer. Further, the outermost layer is preferably a layer having a noble metal as a main component.

The other conductive particles may be formed by coating a surface of a layer containing a transition metal as a core or a transition metal containing a core as a main component, and further coating a layer having a noble metal as a main component. Further, the other conductive particles may be made of insulating particles having a non-conductive glass, ceramics, plastic or the like as a main component, or the surface of the core may be covered with a layer containing the metal or carbon as a main component.

When the other conductive particles are formed by coating the core of the insulating particles with a conductive layer, it is preferable that the insulating particles having a plastic as a main component serve as a core, and the surface of the core is made of a transition metal such as Ni as a main component. The layer is coated, and further, the surface of the layer is coated with the noble metal such as Au as the outermost layer of the main component.

Moreover, since the circuit connecting material of the present invention is excellent in handleability, it is preferably used in the form of a film, and in the meantime, a film-forming polymer may be contained in the adhesive component. As the film-forming polymer, polystyrene, polyethylene, polyvinyl butyral, polyethylene formaldehyde, polyimide, polyamide, polyester, polyvinyl chloride, polyphenylene ether, urea resin, melamine can be used. Resin, phenol resin, xylene resin, epoxy resin, polyisocyanate resin, phenoxy resin, polyimide resin, polyester urethane resin, and the like. Among these A resin having a hydroxyl group functional group improves adhesion, and is therefore more preferable. Further, those in which these polymers are modified by a radical polymerizable functional group can also be used.

The weight average molecular weight of these film-forming polymers is preferably 10,000 or more. Further, if the weight average molecular weight exceeds 1,000,000, the miscibility is lowered, so it is preferably less than 1,000,000.

Further, the circuit connecting material of the present invention may further comprise rubber microparticles, a filler, a softener, an accelerator, an anti-aging agent, a coloring agent, a flame retardant, a thixotropic agent, a coupling agent, a phenol resin, and the like. Melamine resin, isocyanate, and the like.

The rubber fine particle system is characterized in that the average particle diameter of the particles is twice or less of the average particle diameter of the first and second conductive particles to be blended, and the storage elastic modulus at room temperature (25 ° C) is the first and second conductive particles and The storage component of the subsequent component may have a storage elastic modulus of 1/2 or less. In particular, the material of the rubber fine particles is a polysulfonium oxide, an acrylic acid emulsion, or a fine particle system of an SBR, an NBR, or a polybutadiene rubber, and it is suitable for use alone or in combination of two or more. These rubber fine particles having a three-dimensional crosslink are excellent in solvent resistance and can be easily dispersed in the adhesive component.

When the filler material is contained in the circuit connecting material, the reliability of the connection and the like are improved, which is preferable. The filler material can be used as long as its maximum diameter is less than the average particle diameter of the first and second conductive particles. The amount of the filler to be added is preferably in the range of 5 to 60% by volume based on the total solid content of the circuit connecting material. When the blending amount exceeds 60% by volume, the effect of improving the reliability tends to be saturated, and when it is less than 5% by volume, the effect of adding the filler tends not to be sufficiently obtained.

The coupling agent is preferably a compound containing 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, from the viewpoint of improving the adhesion.

Fig. 4 is a schematic cross-sectional view showing a film-like circuit connecting material of an embodiment of the circuit connecting material of the present invention. The film-shaped circuit connecting material 50 contains at least the adhesive component 51, the first conductive particles 10, and the second conductive particles 20. Thus, the processing can be easily performed by making the circuit connecting material into a film shape.

Further, the circuit connecting material of the present invention may be separated into a layer containing a reactive resin, a layer containing a latent curing agent, or a layer containing a hardener capable of generating free radicals and a layer containing conductive particles. When such a structure is formed, an effect of high definition and usable time increase can be obtained.

The circuit connecting material of the present invention can also be used as a film-like adhesive for bonding an IC wafer to a substrate or an electrical circuit. That is, the first circuit member having the first circuit electrode (connection terminal) and the second circuit member having the second circuit electrode (connection terminal) are disposed such that the first circuit electrode and the second circuit electrode face each other. The first circuit electrode and the second circuit electrode disposed opposite each other are heated and pressurized by interposing the circuit connecting material of the present invention, and the first circuit electrode and the second circuit electrode disposed in opposite directions are electrically connected to each other. A circuit connection structure is formed.

The circuit member constituting such a circuit connection structure may be, for example, a wafer component such as a semiconductor wafer, a resistor wafer or a capacitor wafer, or a substrate such as a printed circuit board. The circuit components of these are generally provided with a plurality of (as the case may be singular) circuit electrodes, so that at least one set of circuit components is provided. At least a part of the circuit electrodes of the circuit members are arranged to face each other, and the circuit connecting material of the present invention is interposed between the circuit electrodes arranged in the opposite direction, and the circuit connecting members are electrically connected to each other by heating and pressing to form a circuit connecting structure. body.

By heating and pressurizing at least one of the circuit members, the circuit electrodes disposed in opposite directions are electrically connected by direct contact or intervening of conductive particles of an anisotropic conductive adhesive (circuit connecting material).

When the circuit connecting material of the present invention is connected, the circuit connecting material melts and flows to obtain a connection with respect to the circuit electrode, and hardens to maintain the connector, and the fluidity of the circuit connecting material is an important factor.

On a glass plate having a thickness of 0.7 mm and 15 mm × 15 mm, the circuit connecting material having a thickness of 35 μm and 5 mm × 5 mm is sandwiched, and when it is heated and pressurized at 170 ° C, 2 MPa, and 10 seconds, the initial area (A) is used. The fluidity (B/A) indicated by the area (B) after heating and pressurization is preferably from 1.3 to 3.0, more preferably from 1.5 to 2.5. When the value is less than 1.3, the fluidity is poor, and there is a tendency that a good connection cannot be obtained. When the value exceeds 3.0, bubbles are likely to occur, and the reliability tends to be poor.

The elastic modulus of the circuit connecting material of the present invention at 40 ° C after hardening is preferably from 100 to 3,000 MPa, more preferably from 500 to 2,000 MPa.

Further, the connection method of the circuit electrode of the present invention is such that a circuit connecting material having a hardening property by heat or light is formed on a circuit electrode whose surface is selected from a metal of a gold, silver, tin, and platinum group. Thereafter, the other circuit electrodes are aligned, and heated and pressurized to be connected.

Next, the system of the circuit connection structure of the present invention will be described using the drawings. One of the appropriate forms of the method. Fig. 5 is a cross-sectional view showing the steps of a method of manufacturing the circuit connecting structure of the present invention. Fig. 5 (a) is a cross-sectional view of the circuit member before connecting the circuit members, Fig. 5 (b) is a cross-sectional view of the circuit connection structure when connecting the circuit members, and Fig. 5 (c) is a connection between the circuit members A cross-sectional view of the circuit connection structure.

First, as shown in FIG. 5(a), a circuit-connected circuit connecting material (isotropic conductive adhesive film) in which a circuit connecting material is formed into a film shape is placed on a circuit electrode 72 provided on an LCD panel 73. ) 50.

Then, as shown in FIG. 5(b), the circuit board 75 provided with the circuit electrode 76 is placed on the film-like circuit connecting material 50 such that the circuit electrode 72 and the circuit electrode 76 face each other while being aligned. The film-like circuit connecting material 50 is interposed between the circuit electrode 72 and the circuit electrode 76. Further, the circuit electrodes 72 and 76 have a structure in which a plurality of electrodes are arranged side by side in the depth direction (not shown). Further, the circuit board 75 provided with the circuit electrode 76 is, for example, COF or the like.

The film-like circuit connecting material 50 is a film-like material, so it is easy to handle. Therefore, the film-like circuit connecting material 50 can be easily interposed between the circuit electrode 72 and the circuit electrode 76, and the connection work between the LCD panel 73 and the circuit board 75 can be easily performed.

Then, while heating, the film-like circuit connecting material 50 is pressed in the direction of the arrow A of FIG. 5(b) via the LCD panel 73 and the circuit board 75, and is hardened. Thereby, as shown in FIG. 5(c), the circuit connection structure 70 between the circuit members can be obtained by the circuit connection portion 60 composed of the cured material of the circuit connection material 50. Hardening treatment The method may be one or both of heating and light irradiation depending on the adhesive composition used. The circuit connecting material 50 is subjected to a hardening treatment by pressing the film-like connecting material 50, and the circuit connecting material 50 flows and hardens, and the circuit electrode 72 is electrically connected to the circuit electrode 76, and is mechanically fixed.

Example

In the following, the invention will be described in more detail by way of examples, but the invention is not limited by the examples.

(Example 1) (Synthesis of urethane acrylate)

400 parts by mass of polycaprolactone diol having a weight average molecular weight of 800, 131 parts by mass of 2-hydroxypropyl acrylate, 0.5 parts by mass of dibutyltin dilaurate as a catalyst, and hydroquinone as a polymerization inhibitor 1.0 part by mass of monomethyl ether was mixed while heating to 50 ° C while stirring.

Then, 222 parts by mass of isophorone diisocyanate was dropped, and the mixture was heated to 80 ° C while stirring to carry out a carbamate reaction. After confirming that the reaction rate of the isocyanate group was 99% or more, the temperature was lowered to obtain a urethane acrylate of a radical polymerizable substance.

[Modulation of polyester urethane resin]

Mole with citric acid/propylene glycol/4,4'-diphenylmethane diisocyanate The amount is adjusted to 1.0/1.3/0.25, and the polyester is used as a dicarboxylic acid, a propylene glycol as a diol, a 4,4'-diphenylmethane diisocyanate as an isocyanate, and a polyester is prepared in the following order. A urethane resin.

The solution in which the polyester polyol obtained by the reaction of the dicarboxylic acid and the diol was dissolved in methyl ethyl ketone was placed in a stainless steel pressure cooker equipped with a stirrer, a thermometer, a condenser, and a beaker containing a vacuum generating device and a nitrogen gas introducing tube. Then, a specific amount of isocyanate was charged, and 0.02 parts by mass of dibutyltin laurate was added as a catalyst to 100 parts by mass of the polyester polyol, and the mixture was reacted at 75 ° C for 10 hours, and then cooled at 40 ° C. Further, hexahydropyridine was added and reacted for 30 minutes to carry out chain extension, followed by neutralization with triethylamine.

When the solution after the above reaction is dropped into pure water, the solvent and the catalyst are dissolved in water, and the polyester urethane resin as the ester urethane compound is precipitated. The precipitated polyester urethane resin was dried in a vacuum dryer to obtain a polyester urethane resin.

The weight molecular weight of the obtained polyester urethane resin was measured by a gel-soaked color layer analysis and found to be 30,000.

The polyester urethane resin was dissolved in methyl ethyl ketone to 20% by mass. The methyl ethyl ketone solution of the above polyester urethane resin was applied to a single-faced surface-treated PET film having a thickness of 80 μm using a coating device, and dried at 70 ° C for 10 minutes to prepare a resin film having a thickness of 35 μm. . With respect to this resin film, the temperature dependence of the modulus of elasticity was measured under the conditions of a tensile load of 5 gf and a frequency of 10 Hz using a wide-area dynamic viscoelasticity measuring apparatus. In the obtained elastic modulus-temperature curve, the straight line extending from the front and the rear of the glass transition region is equidistant toward the longitudinal axis. The temperature at the point where the straight line and the curve of the stepwise change portion of the glass transition region intersect (the intermediate point glass transition temperature) was determined as the glass transition region of the polyester urethane resin, and was 105 °C.

[Production of First Conductive Particles a]

A surface of a particle composed of polystyrene which is a core was prepared, and a nickel layer having a thickness of 0.2 μm was provided, and on the outer side of the nickel layer, conductive particles having an average particle diameter of 4 μm of a gold layer having a thickness of 0.04 μm were provided. Further, insulating particles composed of a styrene-(meth)acrylate copolymer were prepared. The surface of the above-mentioned conductive particles was coated with the above-mentioned insulating particles using a Hybridizer, and the first conductive particles a were prepared. The first conductive particle a had a D ₂ /D ₁ of 1/12 and a coverage ratio of 50%.

[Production of second conductive particle a]

A surface of a particle composed of polystyrene which is a core was prepared, and a nickel layer having a thickness of 0.2 μm was provided, and a second conductive particle a having an average particle diameter of 4 μm of Ni protrusion was provided on the outer side of the nickel layer. The Vic of the second conductive particles a has a Vicker's hardness of 350 Hv, a height of the protrusions of 120 nm, and a distance between the protrusions of 420 nm.

[Production of circuit connection materials]

30 parts by mass of the above urethane acrylate as a radically polymerizable substance and 20 parts by mass of a trimeric isocyanate type acrylate (product name: M-325, manufactured by Toagosei Co., Ltd.), 2-methylpropene oxime Phosphate 1 part by mass of an acid ester (product name: P-2M, manufactured by Kyoeisha Chemical Co., Ltd.), and a benzoyl peroxide group (product name: Nyper BMT-K40, manufactured by Nippon Oil & Fats Co., Ltd.) as a free radical generator 60 parts by mass of a 20% by mass methyl ethyl ketone solution of the above polyester urethane resin (solid content: 12 parts by mass) was mixed and stirred to obtain an adhesive component.

The first conductive particles a and the second conductive particles a are prepared and dispersed in an adhesive component to obtain a dispersion for coating. The blending amount of the first conductive particles a and the second conductive particles a is 1.5% by volume based on the total solid content of the dispersion liquid for coating.

The obtained dispersion liquid was applied to a single-faced surface-treated PET film having a thickness of 50 μm using a coating device, and dried at 70 ° C for 10 minutes to form an adhesive layer having a thickness of 16 μm (isoelectric conduction). Adhesive layer) (width 15 cm, length 70 m). The obtained laminate of the adhesive layer and the PET film was cut into a width of 1.5 mm, and the side of the plastic rolling (1.7 mm width) having an inner diameter of 40 mm and an outer diameter of 48 mm was wound into a 50 m side as an inner side of the adhesive film surface. A tape-like circuit connecting material is obtained.

(Examples 2 to 3)

The tape-like circuit connecting materials of Examples 2 to 3 were obtained in the same manner as in Example 1 except that the amounts of the first conductive particles a and the second conductive particles a were changed as shown in Table 1.

(Examples 4 to 6) [Production of First Conductive Particles b]

A surface of a particle composed of polystyrene which is a core was prepared, and a nickel layer having a thickness of 0.09 μm was provided, and on the outer side of the nickel layer, conductive particles having an average particle diameter of 3 μm of a gold layer having a thickness of 0.03 μm were provided. Further, insulating particles composed of a styrene-(meth)acrylate copolymer were prepared. The surface of the conductive particles is coated with the insulating particles using a Hybridizer to prepare the first conductive particles b. The first conductive particles b had a D ₂ /D ₁ of 1/15 and a coverage ratio of 55%.

[Production of Second Conductive Particles b]

A surface of a particle composed of polystyrene which is a core is prepared, and a nickel layer having a thickness of 0.1 μm is provided, and a second conductive particle b having an average particle diameter of 3 μm of Ni protrusion is provided on the outer side of the nickel layer. The Vic of the second conductive particles b has a Vicker's hardness of 350 Hv, a height of the protrusions of 100 nm, and a distance between the protrusions of 200 nm.

[Production of circuit connection materials]

The first conductive particle b and the second conductive particle b were used in place of the first conductive particle a and the second conductive particle a, and the amount of the first conductive particle a and the second conductive particle a was the same as in the first embodiment except for the amount shown in Table 1. A tape-like circuit connecting material of Examples 4 to 6 was obtained.

(Comparative examples 1 to 7) [Production of conductive particles coated with Au]

Preparing a surface for particles composed of polystyrene that becomes a core A nickel layer having a thickness of 0.2 μm was provided, and a gold layer having a thickness of 0.04 μm and an Au-coated conductive particle having an average particle diameter of 4 μm were provided on the outer side of the nickel layer. The Vic's hardness of the Au-coated conductive particles was 150 Hv.

[Production of circuit connection materials]

The tape-like circuit connecting materials of Comparative Examples 1 to 7 were obtained in the same manner as in Example 1 except that the conductive particles shown in Table 2 were used in the same amounts as shown in the same table.

Further, in Tables 1 and 2, the number ratio means the ratio of the number of the first conductive particles to the second conductive particles (the number of the first conductive particles / the number of the second conductive particles). Further, when the second conductive particles are replaced with the conductive particles coated with Au, the number ratio means the ratio of the number of the first conductive particles to the conductive particles coated with Au (the number of the first conductive particles / the conductive particles coated with Au) Number).

(Production of circuit connection structure)

For the circuit components, a coated ITO glass substrate (15-20 Ω/□, full-electrode) with a thickness of 0.7 mm and Cr/IZO [Al (2000 angstrom) + Cr (500 angstroms) +) with a thickness of 0.7 mm are prepared. IZO (1000 angstroms), full-electrode] Two types of circuit components coated with a glass substrate.

The circuit connecting material (1.5 mm in width and 3 cm in length) obtained in the above examples and comparative examples was applied to the ITO-coated glass substrate and the Cr/IZO-coated glass substrate, and the adhesive layer side was directed toward the substrate. The laminate was heat-pressed at 70 ° C and 1 MPa for 2 seconds, and the PET film was peeled off to transfer the adhesive layer to the substrate.

Then, 600 tin-plated copper circuits having a line width of 25 μm, a pitch of 50 μm, and a thickness of 8 μm were formed on a flexible printed circuit board (FPC) on a polyimide film, and the transferred adhesive layer was on the circuit side. It was placed toward the adhesive layer, and was temporarily fixed by pressurizing at 24 ° C and 0.5 MPa for 1 second.

The glass substrate temporarily fixed to the FPC by the adhesive layer is disposed on the pressure bonding device, and the polyethylene oxide rubber having a thickness of 200 μm is used as a buffer material from the FPC side. It is heated and pressurized at 170 ° C and 3 MPa for 6 seconds by heat sealing, and the 俾 covers a width of 1.5 mm for connection. Thereby, a circuit connection structure is obtained.

(Measurement of connection resistance)

The circuit connection structure obtained by the Multimeter (device name: TR6845, manufactured by Advantest Co., Ltd.) was used to measure the circuit electrode of the FPC, the glass substrate coated with ITO for the circuit electrode, or the circuit coated with the Cr/IZO glass substrate. The connection resistance between the electrodes. The connection resistance was measured by measuring the resistance value between the opposing circuit electrodes by 40 points, and the average value thereof was obtained. The results obtained are shown in Tables 3 to 4.

(Measurement of insulation)

A glass substrate formed by using a polyimide film having a thickness of 38 μm, a line width of 50 μm, a line width of 50 μm, and a thickness of 1000 Å at a pitch of 50 μm was obtained by the above-described examples and comparative examples (width). 1.5mm and 3cm long) and crimped. At this time, aggregation of conductive particles occurs at the edge portion of the glass. Fig. 6 is a photograph showing the appearance of the appearance when the conductive particles are aggregated at the edge portion of the glass substrate on which the ITO electrode is formed. Fig. 6 is a photograph of the photographic connector from the glass substrate side, and it was confirmed that the edge portion 17 of the glass substrate on which the ITO electrode 15 was formed was caused to aggregate 16 of the conductive particles. Further, 18 in the figure is a resin flow portion outside the substrate. Then, as shown in FIG. 6, when the aggregate 16 of the conductive particles is generated in the edge portion 17 of the glass substrate, a short circuit is formed between the adjacent ITO electrodes 15 in the circuit connecting material having low insulating properties, and the connection resistance is obtained.

Thereafter, the resistance value between the adjacent ITO electrodes was measured by Multimeter (device name: TR6845, manufactured by Advantest Co., Ltd.). The resistance value was measured by measuring the resistance value between adjacent ITO electrodes by 20 points, and the number of points (electrodes generating short-circuiting) at which a connection resistance of 1 × 10 ¹⁰ Ω or less was obtained was recorded, and the insulation property was evaluated. The results obtained are shown in Tables 3 to 4.

Industrial use possibility

As described above, according to the present invention, it is difficult to cause a short circuit between circuits as compared with the conventional circuit connecting material, and even when a high-resistance electrode such as an IZO electrode is used, a good connection resistance can be obtained, and A circuit connection material and a circuit connection structure excellent in reliability are connected.

1‧‧‧nuclear particles

1a‧‧‧Substrate particles

1b‧‧‧ Conductive layer

2A‧‧‧Insulating particles

2B‧‧‧Insulating layer

10, 10A, 10B‧‧‧ first conductive particles

14‧‧‧Protruding

20, 20A, 20B‧‧‧ second conductive particles

21‧‧‧ nuclear body

21a‧‧‧Nuclear Department

21b‧‧‧Protruding

22‧‧‧metal layer

50‧‧‧film-like circuit connecting materials

51‧‧‧Adhesive ingredients

60‧‧‧Circuit Connection

70‧‧‧Circuit connection structure

72, 76‧‧‧ circuit electrodes

73‧‧‧LCD panel

74‧‧‧LCD display

75‧‧‧ circuit board

Fig. 1 is a schematic cross-sectional view showing a suitable form of the first conductive particles.

Fig. 2 is a schematic cross-sectional view showing another suitable form of the first conductive particles.

Fig. 3 is a schematic cross-sectional view showing a suitable form of the second conductive particles.

Fig. 4 is a schematic cross-sectional view showing an embodiment of a circuit connecting material of the present invention.

Fig. 5 is a cross-sectional view schematically showing the steps of a method of manufacturing the circuit connecting structure of the present invention.

Fig. 6 is a photograph showing the appearance of the appearance when the conductive particles are aggregated at the edge portion of the glass substrate on which the ITO electrode is formed.

10‧‧‧First conductive particles

20‧‧‧Second conductive particles

50‧‧‧film-like circuit connecting materials

51‧‧‧Adhesive ingredients

Claims (13)

A circuit connecting material is a circuit connecting material which is connected between opposite circuit electrodes and which is pressed against a circuit electrode to electrically connect electrodes in a pressurizing direction, and is characterized by containing an adhesive component and a surface. At least a portion of the first conductive particles coated with the insulating covering, and at least a portion of the surface coated with Ni or an alloy or oxide thereof, and having raised second conductive particles, the first conductive particles and the second conductive The number ratio of the particles (the number of the first conductive particles / the number of the second conductive particles) is 0.4 to 3. A circuit connecting material is a circuit connecting material which is provided between a circuit electrode and a circuit electrode which is pressed against a circuit electrode and electrically connected between electrodes in a pressurizing direction, and is characterized in that it contains an adhesive component, and At least a portion of the surface is coated with a first conductive particle covered with an insulating covering, and at least a portion of the surface is covered with a metal, alloy or metal oxide having a Vicker's hardness of 300 Hv or more, and has a second conductive conductive portion. The particles, the number ratio of the first conductive particles to the second conductive particles (the number of the first conductive particles / the number of the second conductive particles) are 0.4 to 3. The circuit connecting material according to claim 1 or 2, wherein the first conductive particles and the second conductive particles are in a volume The ratio (volume of the first conductive particles / volume of the second conductive particles) is 0.4 to 3. The circuit connecting material according to the first or second aspect of the invention, wherein the height of the protrusions is 50 to 500 nm in the second conductive particles, and the distance between the protrusions adjacent to each other is 1000 nm or less. In the circuit connecting material according to the first or second aspect of the invention, the insulating material is provided in the first conductive particles so that the coating ratio is 20 to 70%. The circuit connecting material according to claim 1 or 2, wherein the first conductive particles are provided with conductive core particles and the insulating layer containing a plurality of insulating particles provided on a surface of the core particles. covering, the average particle diameter of the insulating particles (D ₂₎ with an average particle diameter (D ₁₎ of the core particle ratio (D ₂ / D ₁₎ is 1/10 or less based. The circuit connecting material according to the first or second aspect of the invention, wherein the first conductive particles include conductive core particles and the insulating covering layer including an insulating layer, wherein the insulating layer is provided in the foregoing The organic polymer compound on the surface of the core particle has a ratio (T ₂ /D ₁ ) of the thickness (T ₂ ) of the insulating layer to the average particle diameter (D ₁ ) of the core particle of 1/10 or less. The circuit connecting material according to claim 1 or 2, wherein the first conductive particles and the second conductive particles have an average particle diameter of 2 to 6 μm. Such as the circuit connection described in item 1 or 2 of the patent application scope A material in which at least one of the opposite electrode electrodes is an IZO electrode. A circuit connection structure, characterized in that a first circuit member having a first circuit electrode and a second circuit member having a second circuit electrode are disposed such that the first circuit electrode and the second circuit electrode face each other, The circuit connecting material according to any one of the first to eighth aspects of the present invention, wherein the first circuit electrode and the second circuit electrode are disposed opposite each other by pressurization heating to make the opposite direction The first circuit electrode configured to be electrically connected to the second circuit electrode. The circuit-connecting structure according to claim 10, wherein at least one of the first circuit electrode and the second circuit electrode is an ITO electrode. The circuit connection structure according to claim 10, wherein at least one of the first circuit electrode and the second circuit electrode is an IZO electrode. A film-like circuit connecting material obtained by forming a circuit connecting material according to any one of the first to eighth aspects of the invention into a film shape.