JP2003077335A - Surface treated conductive particles, treating method for conductive particles, adhesive for circuit connection using the conductive particles, and circuit connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide conductive particles with excellent preservation stability to the surface of which, a surface treatment is applied, without coating defect on its insulation resin coated conductive resin, and to provide a treatment method for conducive particles, a circuit connecting adhesive using the conductive particles, and a circuit connection structure. SOLUTION: A surface treatment is applied to the conductive particles by using a treatment liquid containing (1) a radical polymerizable compound, (2) an acidic compound, and (3) water. The adhesive for circuit connection is laid between base boards having circuit electrodes facing each other, and the base boards having circuit electrodes facing each other are pressed, and the circuit electrodes laid in the pressing direction are electrically connected. The adhesive for circuit connection contains the surface treated conductive particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to surface-treated conductive particles which have been surface-treated, a method for treating conductive particles, an adhesive for circuit connection using the same, and a circuit connection structure.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display and TCP or F
An anisotropic conductive adhesive in which conductive particles are dispersed in an adhesive is used for connection between PC and TCP and connection between FPC and printed wiring board. In addition, recently, even when a semiconductor silicon chip is mounted on a substrate, so-called flip-chip mounting in which the semiconductor silicon chip is directly mounted face down on the substrate is performed instead of the conventional wire bond. Application of a hydrophilic adhesive has been started (JP-A-59-120436, JP-A-60-
191228, JP-A-1-251787, JP-A-7
-90237).

[0003]

In recent years, with the miniaturization and thinning of electronic equipment, the density of circuits has been increasing, and the spacing between electrodes and the width of electrodes have become extremely narrow. Also, regarding the connection of semiconductor chips, the bumps used for the connection are becoming smaller and the distance between the bumps is becoming very narrow. Generally, when connecting circuits facing each other using an adhesive containing conductive particles, in order to reduce the connection resistance, there are three or more, preferably five or more, conductive particles on the circuit or bump. It is necessary. However, it is necessary to increase the number of conductive particles contained in the adhesive in order to arrange the required number of conductive particles on the circuit even when the width between the circuits and the distance between the bumps are narrowed. However, in this case, the number of conductive particles existing between the circuits also increases, so that there is a problem that the insulating property deteriorates. In order to solve such a problem, measures have been taken so that the conductive particles are coated with an insulating resin so that the insulating property is maintained even when the particles come into contact with each other between circuits (Japanese Patent Laid-Open Publication No. Sho. 62-40183). However, it is difficult to completely cover these conductive particles with an insulating resin, and it becomes difficult to secure the insulating property when the circuit space becomes narrow because the conductive portion is exposed. ing. Further, in the case of complete coating, the insulating material may hinder the contact between the electrode and the particle after the connection, which may increase the connection resistance. Furthermore, if the surface of the conductive particles is active, the curing reaction of the anisotropic conductive adhesive proceeds during storage before use,
When connecting the circuit electrodes between the substrates, there is a problem that the connection cannot be made with an adhesive and the storage stability decreases.
The present invention has no coating defects of the insulating resin coated conductive resin,
Further, the present invention provides a surface-treated conductive particle having excellent storage stability, a method for treating the conductive particle, and a circuit connecting adhesive and a circuit connecting structure using the same.

[0004]

[Means for Solving the Problems] As a result of studying a method for efficiently coating the surface of conductive particles in the above situation,
Co (cobalt), Ni (nickel), Zn (zinc), C
It was found that a conductive resin particle containing a metal such as u (copper) on the surface, a radically polymerizable compound, and an acidic compound can be uniformly formed on the surface of the conductive particle by stirring in the presence of water (water). Came to That is, the first aspect of the present invention is surface-treated conductive particles that have been surface-treated with a treatment liquid containing (1) a radically polymerizable compound, (2) an acidic compound, and (3) water. A second aspect of the present invention is
(1) radically polymerizable compound, (2) acidic compound,
(3) A surface treatment method for surface-treating conductive particles, which comprises performing a surface treatment with a treatment liquid containing water. According to a third aspect of the present invention, an adhesive for circuit connection is interposed between substrates having circuit electrodes facing each other, and a substrate having circuit electrodes facing each other is pressed to electrically connect the electrodes in the pressing direction. A circuit connecting adhesive for connecting, wherein the circuit connecting adhesive uses the surface-treated conductive particles subjected to the surface treatment described above. According to a fourth aspect of the present invention, an adhesive for circuit connection is interposed between substrates having circuit electrodes facing each other, and a substrate having circuit electrodes facing each other is pressed to electrically connect the electrodes in the pressing direction. A connected connection structure, wherein the circuit connection adhesive is an adhesive using the surface-treated conductive particles described above.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive particles used in the present invention are
There is no particular limitation as long as it has electrical conductivity capable of obtaining electrical connection, but it is a conductive particle containing Co, Ni, Zn, Cu, and ceramics, plastics, etc. coated with the above-mentioned conductive substance. Can also be used. Further, particles in which the conductive material is coated with Au or Ag can be used. At this time, the thickness of the metal layer to be coated is preferably 100 Å or more in order to obtain sufficient conductivity. Co, Z
When a noble metal layer is provided on a transition metal such as n, Cu, or Ni, free radicals are generated by the redox action caused by the loss of the noble metal layer or the loss of the noble metal layer that occurs when the conductive particles are mixed and dispersed. The surface treatment of the conductive particles is performed because the pot life is shortened. The conductive particles can be used in the range of 0.1 to 30% by volume, preferably 0.1 to 20% by volume with respect to the adhesive component.

The radically polymerizable compound used in the present invention is a compound having a functional group which is polymerized by radicals,
There are (meth) acrylate resins, maleimide resins, citracone imide resins, nadiimide resins and the like, and two or more kinds may be mixed and used. The radical polymerizable compound can be used in any state of monomer and oligomer, and the monomer and oligomer may be mixed and used. The (meth) acrylate resin is obtained by radically polymerizing (meth) acrylate,
As (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate,
Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylene glycol tetra (meth) acrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2- Screw [4
-(Acryloxymethoxy) phenyl] propane, 2,
2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, tricyclodecanyl (meth) acrylate, tris (acryloxyethyl) isocyanurate, urethane (meth ) Acrylate, isocyanuric acid ethylene oxide-modified diacrylate, mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate, and the like, and may be used alone or in combination of two or more. . Further, if necessary, a radical polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be used within a range that does not impair the curability.

The maleimide resin has at least one maleimide group in the molecule, and examples thereof include phenylmaleimide, 1-methyl-2,4-bismaleimidebenzene, and N, N'-m-phenylenebis. Maleimide, N,
N'-p-phenylene bismaleimide, N, N'-4,4-biphenylene bismaleimide, N, N'-4,4- (3,3-
Dimethylbiphenylene) bismaleimide, N, N'-4,4
-(3,3-Dimethyldiphenylmethane) bismaleimide, N, N'-4,4- (3,3-diethyldiphenylmethane) bismaleimide, N, N'-4,4-diphenylmethane bismaleimide, N, N'- 4,4-diphenylpropane bismaleimide, N, N'-4,4-diphenylether bismaleimide, N, N'-4,4-diphenylsulfone bismaleimide, 2,2-bis (4- (4-maleimidophenoxy) Phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-maleimidophenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4, 4'-cyclohexylidene-bis (1- (4-maleimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-maleimidophene) ) Phenyl) hexafluoropropane there may be used a mixture of two or more in combination.

The citraconimide resin is obtained by polymerizing a citraconimide compound having at least one citraconimide group in the molecule. Examples of the citraconimide compound include phenyl citraconimide and 1-methyl-2. , 4-biscitraconimide benzene, N, N'-m-phenylene biscitraconimide, N, N '
-P-phenylene bis citraconimide, N, N'-4,4
-Biphenylene biscitraconimide, N, N'-4,4-
(3,3-Dimethylbiphenylene) biscitraconimide, N, N'-4,4- (3,3-dimethyldiphenylmethane) biscitraconimide, N, N'-4,4- (3,3-
Diethyldiphenylmethane) biscitraconimide, N,
N'-4,4-diphenylmethanebiscitraconimide,
N, N'-4,4-diphenylpropanebiscitraconimide, N, N'-4,4-diphenyletherbiscitraconimide, N, N'-4,4-diphenylsulfonebiscitraconimide, 2,2-bis ( 4- (4-citraconimidophenoxy) phenyl) propane, 2,2-bis (3
-S-Butyl-3,4- (4-citraconimidophenoxy) phenyl) propane, 1,1-bis (4- (4-
Citraconimidophenoxy) phenyl) decane, 4,
4'-cyclohexylidene-bis (1- (4-citraconimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-citraconimidophenoxy) phenyl) hexafluoropropane, etc., You may use individually or in mixture of 2 or more types.

The nadimide resin is obtained by polymerizing a nadimide compound having at least one nadimide group in the molecule. Examples of the nadimide compound include:
Phenylnadiimide, 1-methyl-2,4-bisnadiimidebenzene, N, N'-m-phenylenebisnadiimide,
N, N'-p-phenylenebisnadiimide, N, N'-4,4-
Biphenylene bis nadiimide, N, N'-4,4- (3,3
-Dimethylbiphenylene) bisnadiimide, N, N'-4,
4- (3,3-dimethyldiphenylmethane) bisnadiimide, N, N'-4,4- (3,3-diethyldiphenylmethane) bisnadiimide, N, N'-4,4-diphenylmethanebisnadiimide, N, N'-4 , 4-diphenylpropane bisnadimide, N, N'-4,4-diphenyl ether bisnadimide, N, N'-4,4-diphenylsulfone bisnadimide, 2,2-bis (4- (4-nadimide phenoxy) Phenyl) propane, 2,2-bis (3-s-
Butyl-3,4- (4-nadiimidophenoxy) phenyl) propane, 1,1-bis (4- (4-nadiimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- ( 4-nadiimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-nadiimidophenoxy) phenyl) hexafluoropropane, and the like, which may be used alone or in combination of two or more. Is also good.

The acidic compound used in the present invention is not particularly limited, and generally acidic compounds can be used. Specifically, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid and hydrofluoric acid, and organic acids such as acetic acid, oxalic acid, formic acid, maleic acid, phthalic acid, isophthalic acid and terephthalic acid can be used. The above acidic compound is used in an amount of 0.01 to 30% by weight based on 100 of the radically polymerizable compound. If it is less than 0.01% by weight, the surface treatment will be incomplete, and it will be difficult to treat the whole particle,
When it is more than the above range, the thickness of the surface treatment layer becomes large and the conductivity decreases. The amount of water used is preferably 0.01 to 50% by weight based on the radically polymerizable compound. If it is less than 0.01% by weight, the surface treatment will be incomplete, and it will be difficult to treat the whole particle,
When it is more than the above range, the thickness of the surface treatment layer becomes large and the conductivity decreases.

The surface treatment of the present invention is preferably performed in an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the radically polymerizable compound, but it is more preferable as long as it can be uniformly mixed with water. As the organic solvent used in the present invention, methanol, ethanol, isopropyl alcohol, acetone, ethyl acetate, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like can be used. Further, even those which are immiscible with water, such as methyl ethyl ketone, toluene, xylene, and cyclohexane, can be used within a range that does not impair the solubility. Of these, methanol, ethanol, acetone, and ethyl acetate are preferable because they can be easily dried after the treatment. The radically polymerizable compound contained in the organic solvent is preferably 0.05 to 10% by weight with respect to 100 of the organic solvent. If the amount is less than 0.05% by weight, the surface treatment becomes incomplete and it becomes difficult to treat the whole particles,
If the amount is more than 0% by weight, the thickness of the surface treatment layer becomes thick and the conductivity is lowered. The treatment conditions for the surface treatment are not particularly limited, but the temperature may be 20 ° C. to 100 ° C. and the time may be 0.5 minutes to 10 hours, and the temperature is appropriately selected depending on the boiling point of the organic solvent used. be able to. The treated conductive particles are separated from the treatment liquid by filtration, centrifugation, etc. and dried before use. The drying conditions are not particularly limited, but it is preferable to select a temperature at which the organic solvent used in the treatment liquid can be completely dried,
The temperature is generally 20 ° C to 150 ° C. The drying time is not particularly limited and is selected from 1 minute to 2 hours.

An adhesive for circuit connection can be obtained by dispersing the surface-treated conductive particles in the adhesive. At this time, conductive particles that have not been surface-treated may be mixed within a range that does not deteriorate the insulating property. The adhesive used in the present invention, styrene-butadiene-styrene copolymer,
Thermoplastic resins such as styrene-isoprene-styrene copolymer and thermosetting resins such as epoxy resin, (meth) acrylic resin, maleimide resin, citracone imide resin, nadiimide resin and phenol resin are used, but heat resistance It is preferable to use a thermosetting resin from the viewpoint of reliability and reliability, especially when using a radical polymerization system using a (meth) acrylic resin, a maleimide resin, a citracone imide resin, a nadimide resin can do.

The (meth) acrylic resin includes (meth)
It is obtained by radically polymerizing an acrylate, and examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, and ethene glycol di (meth) acrylate. Acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylene glycol tetra (meth) acrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloyl) Roxymethoxy) phenyl] propane,
2,2-bis [4- (acryloxyethoxy) phenyl]
Propane, dicyclopentenyl (meth) acrylate tricyclodecanyl (meth) acrylate, tris (acryloxyethyl) isocyanurate, urethane (meth)
Examples thereof include acrylates, which may be used alone or in combination of two or more. Furthermore, when a radical polymerizable substance having a phosphoric acid ester structure is used in the adhesive component, it is possible to improve the adhesive force to an inorganic substance such as a metal. The amount of the radically polymerizable substance having a phosphoric acid ester structure used is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. The radical polymerizable substance having a phosphoric acid ester structure is obtained as a reaction product of phosphoric anhydride and 2-hydroxyethyl (meth) acrylate. Specifically, there are mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate and the like, which may be used alone or in combination. As the maleimide resin, citraconic imide resin and nadimide resin, the same radical polymerizable compounds as described above can be used. When the above radical polymerizable compound is used in the adhesive, a polymerization initiator is used. The polymerization initiator is not particularly limited as long as it is a compound that generates a radical by heat or light, and may be a peroxide, an azo compound, or the like, and may be appropriately selected in consideration of the desired connection temperature, connection time, storage stability, and the like. Although selected, a temperature with a half-life of 10 hours is 4 from the viewpoint of high reactivity and storage stability.
An organic peroxide having a temperature of 0 ° C or higher and a half-life of 1 minute of 180 ° C or lower is preferable, and a temperature of a half-life of 10 hours is 50 ° C.
Above all, an organic peroxide having a half-life of 1 minute at 170 ° C. or lower is particularly preferable. The compounding amount of the polymerization initiator is 1 to 20.
% By weight is preferred and 2 to 15% by weight is particularly preferred. Specific examples of the organic peroxide used in the present invention can be selected from diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, silyl peroxide, and the like. However, peroxyesters, dialkyl peroxides, hydroperoxides, and silyl peroxides have less than 5000 ppm of chlorine ions and organic acids in the initiator, and the organic acids generated after thermal decomposition are small, and the It is particularly preferable because it can suppress corrosion.

Examples of diacyl peroxides include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide and succinic. Examples thereof include peroxide, benzoylperoxytoluene, and benzoylperoxide.

Examples of peroxydicarbonates include di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate and di-2-
Ethoxymethoxyperoxydicarbonate, di (2-
Ethylhexyl peroxy) dicarbonate, dimethoxybutyl peroxydicarbonate, di (3-methyl-
3-methoxybutyl peroxy) dicarbonate and the like can be mentioned.

Peroxyesters include cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxynoedecanoate. , T-hexyl peroxy neodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethyl hexanonate,
2,5-Dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanonate, t
-Hexylperoxy-2-ethylhexanonate, t
-Butyl peroxy-2-ethyl hexanonate, t-
Butyl peroxyisobutyrate, 1,1-bis (t-
Butyl peroxy) cyclohexane, t-hexyl peroxy isopropyl monocarbonate, t-butyl peroxy-3,5,5-trimethylhexanonate, t-
Butyl peroxylaurate, 2,5-dimethyl-2,
5-di (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexylmonocarbonate, t-hexylperoxybenzoate, t-butylperoxyacetate and the like. be able to.

Among the peroxyketals, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (T-butylperoxy) -3,3,5-trimethylcyclohexane, 1,
1- (t-butylperoxy) cyclododecane, 2,2
-Bis (t-butylperoxy) decane and the like.

In the dialkyl peroxides, α,
α'-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide and the like can be mentioned.

Examples of hydroperoxides include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

Examples of the silyl peroxides are t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide and tris ( Examples thereof include t-butyl) vinyl silyl peroxide, t-butyl triallyl silyl peroxide, bis (t-butyl) diallyl silyl peroxide, and tris (t-butyl) allyl silyl peroxide.

Further, in order to suppress the corrosion of the connection terminals of the circuit member, it is preferable that the chlorine ion and the organic acid contained in the organic peroxide be 5000 ppm or less, and further, the organic acid generated after thermal decomposition is Less is more preferable. Further, since the stability of the produced circuit connecting structure is improved, it is preferable to have a weight retention rate of 20% by weight or more after leaving it open at room temperature (25 ° C.) and normal pressure for 24 hours. These can be appropriately mixed and used. These organic peroxides can be used alone or in a mixture, and may be used in a mixture with a decomposition accelerator, a suppressor and the like. Microcapsules obtained by coating these organic peroxides with a polyurethane-based or polyester-based polymer material are preferable because the pot life is extended.

As the epoxy resin used as the adhesive, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin,
Phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin, isocyanate There are nurate type epoxy resins, aliphatic chain epoxy resins, and the like, and these epoxy resins may be halogenated or hydrogenated. Two or more of these epoxy resins may be used in combination.

The above epoxy resin is preferably used in combination with a curing agent, and examples thereof include amines, phenols, acid anhydrides, imidazoles, dicyandiamide and the like which are used as a curing agent for ordinary epoxy resins. . Furthermore, tertiary amines and organic phosphorus compounds that are usually used as a curing accelerator may be used as appropriate. Further, as a method of reacting the epoxy resin, cation polymerization may be performed using a sulfonium salt, an iodonium salt, or the like, other than using the curing agent. Also,
The circuit connecting adhesive of the present invention has a film forming property, an adhesive property, and a polyvinyl butyral resin, a polyvinyl formal resin, a polyester resin, a polyamide resin, a polyimide resin, a xylene resin, and a phenoxy resin in order to impart stress relaxation properties during curing. Polymer components such as resin, polyurethane resin, urea resin may be used. These polymer components preferably have a molecular weight of 10,000 to 10,000,000. Further, these resins may be modified with a radically polymerizable functional group, an epoxy group, a carboxyl group or the like, in which case the heat resistance is improved. The blending amount of the polymer component is 2 to 80% by weight, preferably 5 to 70% by weight, and particularly preferably 10 to 60% by weight. If it is less than 2% by weight, stress relaxation and adhesive force are not sufficient, and if it exceeds 80% by weight, fluidity is lowered. A filler, a softening agent, an accelerator, an antiaging agent, a coloring agent, a flame retardant, and a coupling agent may be added to the adhesive for circuit connection of the present invention as appropriate. Also,
Tg when the adhesive for circuit connection of the present invention is a cured product
A multi-layered structure composed of two or more layers having different (glass transition temperatures) may be used. In the case of a multi-layered structure, the conductive particles may be contained in at least one layer.
The substrate to be adhered using the adhesive for circuit connection of the present invention is not particularly limited as long as it has electrodes that require electrical connection, but ITO or the like used in liquid crystal displays. There are glass or plastic substrates on which electrodes are formed, printed wiring boards, ceramic wiring boards, flexible wiring boards, semiconductor silicon chips, etc., and they are used in combination as necessary. The conditions for connecting are not particularly limited, but the connection temperature is 90 to
The temperature is 250 ° C., the connection time is 1 second to 10 minutes, and it may be appropriately selected depending on the intended use, the adhesive, and the substrate, and post-curing may be performed if necessary. The connection is performed by heating and pressurizing, but energy other than heat, such as light, ultrasonic waves, electromagnetic waves, etc., may be used if necessary.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited to these examples. (Preparation of Surface Treated Conductive Particles A) A solution of 0.5 g of dicyclohexylmethacrylate as a radically polymerizable compound, 0.01 g of phosphoric acid as an acidic compound, 0.5 g of water, and 50 g of methanol was added to the surface of particles having polystyrene as a nucleus. A nickel layer having a thickness of 0.2 μm was provided on the above, and conductive particles having an average particle diameter of 4 μm, in which a gold layer having a thickness of 0.04 μm was provided outside the nickel layer, were stirred at 40 ° C. for 30 minutes. After filtering the conductive particles, the particles were dried at 50 ° C. for 15 minutes to obtain surface-treated conductive particles A. (Preparation of surface-treated conductive particles B) 0.03 g of urethane acrylate and 0.1 g of phosphoric acid ester acrylate as radically polymerizable compounds, acetic acid as acidic compound
0.02g, water 0.5g, methyl ethyl ketone 50g
In the above solution, a nickel layer having a thickness of 0.2 μm was provided on the surface of particles having polystyrene as a nucleus, and a gold layer having a thickness of 0.04 μm was provided on the outside of the nickel layer.
The conductive particles of (1) were added and stirred at 50 ° C. for 5 minutes. After separating the conductive particles by filtration, the particles were dried at 80 ° C. for 5 minutes to obtain surface-treated conductive particles B. (Preparation of surface-treated conductive particles C) 0.03 g of urethane acrylate and 0.1 g of phosphoric acid ester acrylate as radically polymerizable compounds, acetic acid as acidic compound
0.02g, water 0.5g, methyl ethyl ketone 50g
Add nickel metal having an average particle size of 5 μm to the solution of 3
The mixture was stirred at 0 ° C for 5 minutes. After filtering the conductive particles, it was dried at 80 ° C. for 5 minutes to obtain surface-treated conductive particles C. (Preparation of Surface-treated Particles D) A solution of 0.01 g of isocyanurate-modified acrylate as a radically polymerizable compound, 0.02 g of hydrochloric acid as an acidic compound, 0.5 g of water, and 50 g of ethanol is charged with cobalt metal having an average particle diameter of 5 μm, The mixture was stirred at 30 ° C for 1 hour. After filtering the conductive particles,
It was dried at 100 ° C. for 5 minutes to obtain surface-treated conductive particles D. Each of these conductive particles A, B, C, and D was blended in the following formulation, and a simple coating machine (manufactured by Tester Sangyo Co., Ltd.) was used to surface-treat one side having a thickness of 50 μm. It was applied to a fterate film and dried with hot air at 70 ° C. for 10 minutes to prepare an adhesive for circuit connection.

(Example 1) Phenoxy resin (PKHC,
Union Carbide Co., Ltd. trade name, average molecular weight 4
5,000) 20 g, epoxy resin (YD-12
7, Toto Kasei Co., Ltd. product name, bisphenol A type epoxy resin) 50 g, microcapsule type imidazole (HX-37722, Asahi Chiba Co., Ltd. product name) 30 g
Was dissolved and mixed using toluene as a solvent, and further 3% by volume of the surface-treated particles A were mixed and dispersed. A polyethylene terephthalate film having a thickness of 50 μm, one surface of which was surface-treated, was applied using a simple coating machine and dried at 70 ° C. for 10 minutes to obtain a circuit connecting adhesive having a thickness of 30 μm.

(Example 2) Phenoxy resin (PKHC,
Union Carbide Co., Ltd. trade name, average molecular weight 4
5,000) 20 g, epoxy resin (YD-127,
Toto Kasei Co., Ltd. product name, bisphenol A type epoxy resin) 50 g, microcapsule type imidazole (HX-37722, Asahi Ciba Co., Ltd. product name) 30
g was dissolved and blended with toluene as a solvent, and further 3% by volume of the surface-treated particles C were blended and dispersed. It is applied to a polyethylene terephthalate film having a thickness of 50 μm, which has been surface-treated on one side, using a simple coating machine and dried at 70 ° C. for 10 minutes,
An adhesive for circuit connection having a thickness of 30 μm was obtained.

(Example 3) Phenoxy resin (PKHC,
Union Carbide Co., Ltd. trade name, average molecular weight 4
5,000) 50 g, dicyclohexyl methacrylate 48 g, phosphoric acid ester acrylate 2 g,
3 g of 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane was dissolved and mixed with methyl ethyl ketone as a solvent, and further 3% by volume of the surface-treated particles A was mixed and dispersed. A polyethylene terephthalate film having a thickness of 50 μm, which has been surface-treated on one side, is applied using a simple coater, dried at 70 ° C. for 10 minutes, and has a thickness of 30 μm.
An adhesive for circuit connection was obtained.

(Example 4) Phenoxy resin (PKHC,
Union Carbide Co., Ltd. trade name, average molecular weight 4
5,000) 50 g, isocyanuric acid ethylene oxide modified diacrylate 46 g, phosphate ester acrylate 4 g, 2,5-dimethyl-2,5-bis (2
3 g of -ethylhexanoylperoxy) hexane was dissolved and compounded using methyl ethyl ketone as a solvent, and 3% by volume of surface-treated particles B was compounded and dispersed. A polyethylene terephthalate film having a thickness of 50 μm, one surface of which was surface-treated, was applied using a simple coating machine and dried at 70 ° C. for 10 minutes to obtain a circuit connecting adhesive having a thickness of 30 μm.

(Example 5) Phenoxy resin (PKHC,
Union Carbide Co., Ltd. trade name, average molecular weight 4
5,000) 25 g, polyurethane resin 25 g, dicyclohexyl methacrylate 48 g, phosphoric acid ester acrylate 2 g, 2,5-dimethyl-2,5-
Bis (2-ethylhexanoylperoxy) hexane
3 g was dissolved and blended using methyl ethyl ketone as a solvent, and further 3% by volume of surface-treated particles C were blended and dispersed. Thickness 50
A polyethylene terephthalate film having a surface treated with a thickness of μm was applied using a simple coater and dried at 70 ° C. for 10 minutes to obtain a circuit connecting adhesive having a thickness of 30 μm.

(Example 6) Phenoxy resin (PKHC,
Union Carbide Co., Ltd. trade name, average molecular weight 4
5,000) 25 g, polyurethane resin 25 g, dicyclohexyl methacrylate 48 g, phosphoric acid ester acrylate 2 g, 2,5-dimethyl-2,5-
Bis (2-ethylhexanoylperoxy) hexane
3 g of methyl ethyl ketone was dissolved and mixed in a solvent, and further 3% by volume of surface-treated particles D were mixed and dispersed. Thickness 50
A polyethylene terephthalate film having a surface treated with a thickness of μm was applied using a simple coater and dried at 70 ° C. for 10 minutes to obtain a circuit connecting adhesive having a thickness of 30 μm.

Comparative Examples 1 to 6 The circuit connecting adhesives of Examples 1 to 6 were obtained by using untreated particles to obtain circuit connecting adhesives having a thickness of 30 μm.

Comparative Example 7 An adhesive for circuit connection was prepared in the same manner as in Example 1 except that the conductive particles in the adhesive for circuit connection of Example 1 were used as commercially available surface-coated particles having an average particle diameter of 4 μm. Obtained. The coating thickness was about 0.1 μm as measured with a scanning electron microscope. Similarly, the coating thickness of Examples 1 to 6 was about 0.01 μm.

(Production of Circuit Connection Structure) Silicon chip having gold bumps with a height of 15 μm (space between circuit bumps: 10 μm, bump area: 1500 μm ² ), and a circuit board on which an ITO circuit with a height of 1 μm is formed on a glass substrate. (Pitch 40 μm) was used for connection. First, temporary connection was performed on a glass substrate with ITO at 70 ° C. for 5 seconds. After that, the PET film was peeled off, the chips were arranged while aligning the upper and lower circuits, and a circuit connection structure was prepared under the conditions of 170 ° C. and 10 seconds. (Characteristic Evaluation Method) Using this circuit connection structure, the connection resistance between the upper and lower circuits (4-terminal method) was measured. The initial connection resistance and the connection resistance after treatment in a high temperature and high humidity tank at 85 ° C. and 85% RH for 500 hours were also measured. Next, the insulation resistance between the horizontal circuits (distance between the circuits: 10 μm, 20 ° C., 50% RH, energization time: 60 s, applied voltage: 50 V) was measured at 50 locations to determine the short circuit occurrence rate. The results of these measurements are summarized in Table 1.

[0034]

[Table 1]

In Examples 1 to 6 of the present invention, the connection resistance is low and no short circuit occurs, which is good. In Comparative Examples 1 to 6 in which the surface-treated conductive particles are not used, however, a short circuit occurs and the insulation reliability is high. The sex is declining. In Comparative Example 7 using the commercially available surface-coated particles, the initial connection resistance is high.

[0036]

According to the present invention, a connection structure having a low connection resistance and good insulation reliability can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01B 1/22 H01B 1/22 D H01L 21/60 311 H01L 21/60 311S H05K 3/36 H05K 3/36 A (72) Inventor Hiroshi Ono 48 Wadai, Tsukuba-shi, Ibaraki Hitachi Chemical Co., Ltd. Research Institute F-term (reference) 4J037 AA04 CA05 CA18 CA20 CA22 CB09 CB12 CC16 CC17 CC30 EE02 EE12 EE43 EE47 FF11 FF23 4J040 DF041 DF051 DG001 DM011 EB051 EC001 FA181 HA066 JB03 JB10 KA03 KA07 KA32 LA09 NA20 5E344 AA01 AA22 BB02 BB06 CD02 DD06 EE06 EE21 5F044 LL09 RR17 5G301 DA02 DA06 DA10 DA15 DA29 DA42 DA51 DD03

Claims (5)

[Claims] 1. Surface-treated conductive particles which have been surface-treated with a treatment liquid containing (1) a radically polymerizable compound, (2) an acidic compound, and (3) water. 2. The surface-treated conductive particles according to claim 1, wherein the conductive particles are conductive particles containing Co, Ni, Zn, and Cu. 3. A surface treatment method for surface-treated conductive particles, which comprises performing a surface treatment with a treatment liquid containing (1) a radically polymerizable compound, (2) an acidic compound, and (3) water. 4. A circuit connection in which an adhesive for circuit connection is interposed between substrates having circuit electrodes facing each other, and a substrate having circuit electrodes facing each other is pressed to electrically connect the electrodes in the pressing direction. An adhesive for circuit connection, wherein the adhesive for circuit connection contains the surface-treated conductive particles according to claim 1 or 2. 5. A connection structure in which an adhesive for circuit connection is interposed between substrates having circuit electrodes facing each other, and the substrates having circuit electrodes facing each other are pressed to electrically connect the electrodes in the pressing direction. A body, wherein the circuit connecting adhesive is the body.
Alternatively, a circuit connecting structure which is an adhesive containing the surface-treated conductive particles according to claim 2.