JP6533369B2 - Conductive material and connection structure - Google Patents

Description

  The present invention relates to a conductive material containing conductive particles, and can be used, for example, to electrically connect electrodes of various connection target members such as a flexible printed substrate, a glass substrate, a glass epoxy substrate, and a semiconductor chip. It relates to a conductive material. The present invention also relates to a connection structure using the above-mentioned conductive material.

  Paste-like or film-like anisotropic conductive materials are widely known. In the anisotropic conductive material, a plurality of conductive particles are dispersed in a binder resin.

  The anisotropic conductive material is, for example, a connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass)) and a connection between a semiconductor chip and a flexible printed substrate (COF (COF) to obtain various connection structures. It is used for chip on film), connection between semiconductor chip and glass substrate (COG (chip on glass)), connection between flexible printed circuit board and glass epoxy substrate (FOB (film on board)), and the like.

  As an example of the anisotropic conductive material, Patent Document 1 below discloses an anisotropic conductive paste for connecting an electronic component and a wiring substrate. The anisotropic conductive paste comprises 10% by mass or more and 50% by mass or less of lead-free solder powder having a melting point of 240 ° C. or less, and 50% by mass of a thermosetting resin composition containing a thermosetting resin and an organic acid. Above, 90 mass% or less is included. The acid value of the thermosetting resin composition is 15 mg KOH / g or more and 55 mg KOH / g.

  Patent Document 2 below discloses a conductive adhesive containing an epoxy-based adhesive having a flux action and a SnBi-based solder powder.

  Patent Document 3 below discloses a solder paste containing flux and solder particles.

JP 2012-216770 A JP, 2006-199937, A Japanese Patent Application Laid-Open No. 05-92296

  In conventional anisotropic conductive materials as described in Patent Documents 1 to 3, the adhesion between the cured product and the object to be bonded bonded by the cured product may be low.

  An object of the present invention is to provide a conductive material capable of enhancing the adhesion between a cured product and an object to be bonded by the cured product, and to provide a connection structure using the conductive material. is there.

  According to a broad aspect of the present invention, the conductive particles comprising at least the conductive outer surface being a solder, a curable compound, a curing agent, and (meth) acrylic acid, as described above in 100% by weight of the conductive material A conductive material is provided, wherein the content of (meth) acrylic acid is 0.0001% by weight or more and 0.1% by weight or less.

  In a specific aspect of the conductive material according to the present invention, the content of the (meth) acrylic acid in 100% by weight of the conductive material is 0.05% by weight or less.

  In a specific aspect of the conductive material according to the present invention, the content of the (meth) acrylic acid in 100% by weight of the conductive material is 0.005% by weight or more.

  In one specific aspect of the conductive material according to the present invention, the conductive material contains epoxy (meth) acrylate as the curable compound.

  In one particular aspect of the conductive material according to the present invention, the conductive material is a circuit connection material used for electrical connection between electrodes.

  According to a broad aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the first connection target member And a connection portion connecting the second connection target member, the connection portion is formed of the above-described conductive material, and the first electrode and the second electrode are the conductive particles. A connection structure is provided which is electrically connected by

  The conductive material according to the present invention comprises conductive particles of which at least the conductive outer surface is a solder, a curable compound, a curing agent, and (meth) acrylic acid, and the above in 100% by weight of the conductive material. Since the content of (meth) acrylic acid is 0.0001% by weight or more and 0.1% by weight or less, the adhesion between the cured product and the object to be bonded by the cured product can be enhanced.

FIG. 1 is a cross-sectional view schematically showing conductive particles contained in a conductive material according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a modification of the conductive particles. FIG. 3 is a cross-sectional view showing another modified example of the conductive particle. FIG. 4 is a front sectional view schematically showing a connection structure using a conductive material according to an embodiment of the present invention. FIG. 5 is a front cross-sectional view schematically showing an enlarged connection portion between the conductive particles and the electrode in the connection structure shown in FIG.

  Hereinafter, the present invention will be described in detail.

  The conductive material according to the present invention includes conductive particles in which at least the conductive outer surface is a solder, a curable compound, a curing agent, and (meth) acrylic acid. The content of the (meth) acrylic acid in 100% by weight of the conductive material according to the present invention is 0.0001% by weight or more and 0.1% by weight or less.

  By adopting the composition described above in the present invention, particularly by using a small amount of (meth) acrylic acid, it is possible to enhance the adhesion between a cured product of a conductive material and an object to be bonded by the cured product. it can. Furthermore, after being exposed to high humidity, it is possible to maintain high adhesion between the cured product of the conductive material and the object to be bonded bonded by the cured product.

  Furthermore, by adopting the composition described above in the present invention, viscosity change can be suppressed during storage of the conductive material, particularly by using (meth) acrylic acid in a small amount. In particular, when the conductive material is a conductive paste, the viscosity change can be effectively suppressed. Furthermore, by adopting the composition described above in the present invention, connection resistance can be kept low after being exposed to high humidity, particularly by using a small amount of (meth) acrylic acid.

  The content of the (meth) acrylic acid in 100% by weight of the conductive material according to the present invention may be 0.001% by weight or more. The content of the (meth) acrylic acid in 100% by weight of the conductive material according to the present invention is preferably 0.005% by weight or more. In this case, the adhesion between the cured product of the conductive material and the bonding target adhered by the cured product can be further enhanced, and after being exposed to high humidity, the cured product of the conductive material and The adhesion to the adherend adhered by the cured product can be maintained high more effectively.

  The content of the (meth) acrylic acid in 100% by weight of the conductive material according to the present invention is preferably 0.05% by weight or less. When the content of (meth) acrylic acid is 0.05% by weight or less, the adhesion between the cured product and the object to be bonded is further enhanced, and the change in viscosity is further suppressed during storage of the conductive material, Furthermore, after being exposed to high humidity, the connection resistance can be more effectively kept low.

  The acid value of the conductive material is preferably 0.01 mg KOH / g or more, more preferably 0.02 mg KOH / g or more, preferably 10 mg KOH / g or less, more preferably 3 mg KOH / g or less. When the acid value is above the lower limit and below the upper limit, both excellent reaction rate and excellent flux effect can be achieved at a still higher level.

  The above (meth) acrylic acid may be contained as an impurity in a component at the time of mixing of the respective components (curable compound, curing agent, etc.), and is blended separately from each component (curable compound, curing agent, etc.) Post addition).

  The conductive material according to the present invention is preferably a conductive material that can be cured by heating. In this case, the solder at the conductive outer surface of the conductive particles can be melted by the heat at the time of curing the conductive material by heating. The conductive material according to the present invention may be a conductive material that can be cured by both light irradiation and heating. In this case, after the conductive material is semi-cured (B-staged) by light irradiation to reduce the flowability of the conductive material, the conductive material can be cured by heating.

  Hereinafter, first, each component contained in the conductive material according to the present invention, and each component which is preferably contained will be described in detail.

(Curable compound)
The curable compound is not particularly limited as long as it can be cured by the action of a curing agent. The said curable compound is a compound different from (meth) acrylic acid. Only one type of the curable compound may be used, or two or more types may be used in combination.

  It does not specifically limit as said curable compound, The curable compound which has an unsaturated double bond, the curable compound which has an epoxy group, etc. are mentioned.

  As a curable compound which has the said unsaturated double bond, the curable compound etc. which have a vinyl group or a (meth) acryloyl group are mentioned. From the viewpoint of easily controlling the curing of the conductive material or further enhancing the conduction reliability in the connection structure, the curable compound having the unsaturated double bond is a curing having a (meth) acryloyl group. It is preferable that it is a sex compound. The use of the curable compound having a (meth) acryloyl group makes it easy to control the curing ratio within a suitable range for the entire B-staged conductive material, and the conduction reliability in the obtained connection structure is further enhanced. Get higher.

  From the viewpoint of easily controlling the curing rate of the B-staged conductive material and further enhancing the conduction reliability of the connection structure obtained, the curable compound having a (meth) acryloyl group is a (meth) acryloyl group. It is preferred to have one or two groups.

  An ester compound obtained by reacting (meth) acrylic acid and a compound having a hydroxyl group, and an epoxy obtained by reacting (meth) acrylic acid and an epoxy compound as the curable compound having a (meth) acryloyl group. Preferably used are meth) acrylates or urethane (meth) acrylates obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with an isocyanate. The above "(meth) acryloyl group" indicates an acryloyl group and a methacryloyl group. The above "(meth) acrylic" indicates acrylic and methacrylic. The above "(meth) acrylate" indicates acrylate and methacrylate.

  The curable compound may be an epoxy compound (curable compound having an epoxy group). The epoxy compound may be a compound having an epoxy group at an end such as a phenoxy resin, and the compound may be an oligomer or a polymer.

  When the (meth) acrylic acid and the epoxy compound are reacted to obtain an epoxy (meth) acrylate, (meth) acrylic acid may remain as an impurity. However, in the case of using epoxy (meth) acrylate mixed with (meth) acrylic acid as the impurity, the content of (meth) acrylic acid in 100% by weight of the obtained conductive material is 0.0001% by weight or more, It is necessary to control to 0.1 weight% or less. Therefore, it is preferable that a large amount of (meth) acrylic acid is not mixed with the above-mentioned epoxy (meth) acrylate. When a large amount of (meth) acrylic acid is contained after the synthesis of the epoxy (meth) acrylate, it is preferable to perform purification and remove a part or all of the (meth) acrylic acid to use an epoxy (meth) acrylate.

  From the viewpoint of further enhancing the adhesion between the cured product and the object to be bonded, the conductive material preferably contains epoxy (meth) acrylate. The said epoxy (meth) acrylate is a compound (The compound in which the reaction which introduce | transduced the (meth) acryl group with respect to all the epoxy groups was performed) with which all the epoxy groups were converted into the (meth) acryloyl group. The epoxy (meth) acrylate may be a compound having an epoxy group at an end such as a phenoxy resin, and the compound may be an oligomer or a polymer.

  The ester compound obtained by reacting the (meth) acrylic acid with the compound having a hydroxyl group is not particularly limited. As the ester compound, any of monofunctional ester compounds, bifunctional ester compounds and trifunctional or higher ester compounds can be used.

  The curable compound having an unsaturated double bond may be a crosslinkable compound or a non-crosslinkable compound.

  Specific examples of the crosslinkable compound include, for example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerin methacrylate acrylate, pentaerythritol tri (meth) acrylate, tri Methylol propane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, polyester (meth) acrylate, urethane (meth) acrylate and the like can be mentioned.

  Specific examples of the non-crosslinkable compound include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl Examples include (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate and tetradecyl (meth) acrylate.

  The curable compound having an epoxy group preferably has an aromatic ring. Examples of the aromatic ring include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetracene ring, chrysene ring, triphenylene ring, tetraphene ring, pyrene ring, pentacene ring, picene ring and perylene ring. Among them, the aromatic ring is preferably a benzene ring, a naphthalene ring or an anthracene ring, and more preferably a benzene ring or a naphthalene ring. In addition, a naphthalene ring is preferable because it has a planar structure and can be cured more rapidly.

  As the curable compound having an epoxy group, resorcinol type epoxy compound, naphthalene type epoxy compound, anthracene type epoxy compound, bisphenol A type epoxy compound, bisphenol F type epoxy compound, cresol novolac type epoxy compound, phenol novolac type epoxy compound, Glycidyl ester type epoxy compound obtained by reacting a polybasic acid compound having an aromatic skeleton with epichlorohydrin, a glycidyl ether type epoxy compound having an aromatic skeleton, 2- (3,4-epoxy) cyclohexyl-5 5-Spiro- (3,4-epoxy) cyclohexane-m-dioxane, 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate, dicyclopentadienediol Sid, vinylcyclohexene monoxide, 1,2-epoxy-4-vinylcyclohexane, 1,2: 8,9-diepoxylimonene, ε-caprolactone modified tetra (3,4-epoxycyclohexylmethyl) butane tetracarboxylate, 2 And 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2-bis (hydroxymethyl) -1-butanol and the like.

  The content of the curable compound having an unsaturated double bond is preferably 10% by weight or more, more preferably 20% by weight or more, preferably 50% by weight or less, and more preferably 40% by weight in 100% by weight of the conductive material. % Or less.

  The content of the curable compound having an epoxy group is preferably 10% by weight or more, more preferably 20% by weight or more, preferably 50% by weight or less, and more preferably 40% by weight or less in 100% by weight of the conductive material. is there.

  In 100% by weight of the conductive material, the total content of the curable compound is preferably 30% by weight or more, more preferably 40% by weight or more, preferably 90% by weight or less, and more preferably 60% by weight or less.

(Hardening agent)
The conductive material contains a curing agent. Only one type of the curing agent may be used, or two or more types may be used in combination.

  The curing agent of the curable compound having an unsaturated double bond may be a photo or thermal radical polymerization initiator.

  The light or heat radical polymerization initiator generates radical species by light irradiation or heating. The said light or heat radical polymerization initiator advances hardening of the curable compound which has a radically polymerizable group. The light or heat radical polymerization initiator is not particularly limited. As the light or heat radical polymerization initiator, conventionally known light or heat radical polymerization initiators can be used. The light or heat radical polymerization initiator may be a light radical polymerization initiator or a heat radical polymerization initiator. The photo radical initiator may be used alone or in combination of two or more.

  The above photo radical polymerization initiator is not particularly limited, and acetophenone photo radical polymerization initiator, benzophenone photo radical polymerization initiator, thioxanthone, ketal photo radical polymerization initiator, halogenated ketone, acyl phosphinooxide, acyl phosphonate etc. Can be mentioned.

  Specific examples of the acetophenone photoradical polymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one, Examples include methoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-2-cyclohexylacetophenone. A benzyl dimethyl ketal etc. are mentioned as a specific example of the said ketal light radical polymerization initiator.

  It does not specifically limit as said thermal radical polymerization initiator, An azo compound, an organic peroxide, etc. are mentioned. Examples of the organic peroxide include diacyl peroxide compounds, peroxy ester compounds, hydroperoxide compounds, peroxy dicarbonate compounds, peroxy ketal compounds, dialkyl peroxide compounds, and ketone peroxide compounds.

  As the above-mentioned azo compound, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 1 1′-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2′-azobisisobutyrate, dimethyl-2,2′-azobis (2-methylpropionate), dimethyl-1,1′-azobis (1-cyclohexanecarboxylate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-amidinopropane) dihydrochloride, 2-tert-butylazo-2-cyanopropane, 2 , 2′-azobis (2-methylpropionamide) dihydrate, and 2,2′-azobis (2,4,4-trimethylpentane).

  Examples of the diacyl peroxide compound include benzoyl peroxide, diisobutyryl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, and disuccinic acid peroxide. As the above peroxy ester compounds, cumyl peroxy neodecanoate, 1,1,3,3-tetramethyl butyl peroxy neo decanoate, tert-hexyl peroxy neodecanoate, tert-butyl peroxy neo Decanoate, tert-butylperoxy neoheptanoate, tert-hexylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2 , 5-di (2-ethylhexanoylperoxy) hexane, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, tert-butylperoxy-2-ethylhexanoate, tert -Butyl peroxyisobutyrate, tert-butyl peroxy Kishiraureto, tert- butylperoxy isophthalate, tert- butylperoxy acetate, tert- butylperoxy octoate and tert- butyl peroxybenzoate, and the like. Examples of the hydroperoxide compound include cumene hydroperoxide and p-menthane hydroperoxide. Examples of the peroxydicarbonate compound include di-sec-butylperoxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propylperoxydicarbonate, diisopropyl peroxycarbonate, and di-peroxydicarbonate compounds. (2-ethylhexyl) peroxy carbonate etc. are mentioned. Further, as other examples of the above-mentioned peroxide, methyl ethyl ketone peroxide, potassium persulfate, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane and the like can be mentioned.

  The decomposition temperature for obtaining a 10 hour half life of the thermal radical polymerization initiator is preferably 30 ° C. or more, more preferably 40 ° C. or more, preferably 90 ° C. or less, more preferably 80 ° C. or less. If the decomposition temperature for obtaining a 10-hour half-life of the thermal radical polymerization initiator is less than 30 ° C., the storage stability of the curable composition tends to decrease, and if it exceeds 90 ° C., the curing occurs. It tends to be difficult to fully heat cure the sexing composition.

  The content of the light or heat radical polymerization initiator is not particularly limited. The content of the light or heat radical polymerization initiator is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, preferably 10 parts by weight or less, based on 100 parts by weight of the curable compound. More preferably, it is 5 parts by weight or less. The content of the light or heat radical polymerization initiator is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight, with respect to 100 parts by weight of the curable compound having the unsaturated double bond. The content is preferably 10 parts by weight or less, more preferably 5 parts by weight or less. When the content of the light or heat radical curing agent is not less than the lower limit and not more than the upper limit, quick curing of the composition and moisture and heat resistance of a cured product are enhanced in a well-balanced manner.

  Examples of the curing agent for the curable compound having an epoxy group include an imidazole curing agent, an amine curing agent, a phenol curing agent, a polythiol curing agent, a cation generator and an acid anhydride. Among these, an imidazole curing agent, a polythiol curing agent or an amine curing agent is preferable because the conductive material can be cured more rapidly at low temperature. Moreover, since a storage stability becomes high when the curable compound which can be hardened | cured by heating and the said thermosetting agent are mixed, a latent hardening agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. Only one type of these curing agents may be used, or two or more types may be used in combination. The curing agent may be coated with a polymeric substance such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, and 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-Diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine and 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s- The triazine isocyanuric acid adduct etc. are mentioned.

  The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate and dipentaerythritol hexa-3-mercaptopropionate. .

  The amine curing agent is not particularly limited, and hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5] Undecane, bis (4-aminocyclohexyl) methane, metaphenylene diamine, diaminodiphenyl sulfone and the like can be mentioned.

  Examples of the cation generator include iodonium-based cation curing agents, oxonium-based cation curing agents, and sulfonium-based cation curing agents. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate and the like. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate and the like. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate and the like.

  From the viewpoint of further enhancing the flux effect, the curing agent preferably contains a cation generator. The conductive material preferably contains a cation generator.

  The content of the curing agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, and more preferably 100 parts by weight with respect to 100 parts by weight of the curable compound. The content is more preferably 75 parts by weight or less. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, and preferably 200 parts by weight or less, based on 100 parts by weight of the curable compound having an epoxy group. More preferably, it is 100 parts by weight or less, still more preferably 75 parts by weight or less. It is easy to fully harden a conductive material as content of the above-mentioned hardening agent is more than the above-mentioned minimum. When the content of the curing agent is less than or equal to the above upper limit, the excess curing agent which did not participate in curing after curing hardly remains, and the heat resistance of the cured product is further enhanced.

  When the curing agent contains a cation generator, the content of the cation generator is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight, with respect to 100 parts by weight of the curable compound. The content is preferably 10 parts by weight or less, more preferably 5 parts by weight or less. When the content of the cation generator is at least the lower limit and the upper limit, the conductive material is sufficiently cured.

(flux)
The conductive material preferably contains a flux. The use of the flux makes it difficult to form an oxide film on the solder surface, and the oxide film formed on the solder surface or the electrode surface can be effectively removed. As a result, the conduction reliability in the connection structure is further enhanced. In addition, the said electrically-conductive material does not necessarily need to contain the flux.

  The flux is not particularly limited. As the flux, a flux generally used for solder bonding or the like can be used. Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid and rosin. Etc. Only one type of flux may be used, or two or more types may be used in combination.

  Ammonium chloride etc. are mentioned as said molten salt. Examples of the organic acid include lactic acid, citric acid, stearic acid and glutamic acid. Examples of the rosin include activated rosin and non-activated rosin. The flux is preferably rosin. The use of rosin results in even lower connection resistance between the electrodes.

The above-mentioned rosins are rosins mainly composed of abietic acid. The flux is preferably rosins, more preferably abietic acid. The use of this preferred flux results in even lower connection resistance between the electrodes. The flux is preferably an organic acid having a carboxyl group. Examples of the compound having a carboxyl group include a compound in which a carboxyl group is bonded to an alkyl chain, and a compound in which a carboxyl group is bonded to an aromatic ring. In the compound having these carboxyl groups, a hydroxyl group may be further bonded to the alkyl chain or the aromatic ring. The number of carboxyl groups bonded to the alkyl chain or the aromatic ring is preferably 1 to 3, and more preferably 1 or 2. The carbon number of the alkyl chain in the compound in which a carboxyl group is bonded to the alkyl chain is preferably 3 or more, preferably 8 or less, more preferably 6 or less. Specific examples of compounds in which a carboxyl group is bonded to an alkyl chain include hexanoic acid (CH ₃ (CH ₂ ) ₄ COOH), heptanoic acid (CH ₃ (CH ₂ ) ₅ COOH), glutaric acid (HOOC (CH ₂ ) ₃ COOH), adipic acid (HOOC (CH ₂ ) ₄ COOH), and pimelic acid (HOOC (CH ₂ ) ₅ COOH), and the like. Examples of the compound having a carboxyl group and a hydroxyl group include malic acid and citric acid. Specific examples of compounds in which a carboxyl group is bonded to an aromatic ring include benzoic acid, phthalic acid, benzoic anhydride and phthalic anhydride.

  The said flux may be disperse | distributed in binder resin, and may be adhering on the surface of the said electroconductive particle.

  The content of the flux is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less, based on 100% by weight of the conductive material. When the content of the flux is above the lower limit and below the upper limit, it becomes more difficult to form an oxide film on the solder surface, and furthermore, the oxide film formed on the solder surface or electrode surface is removed more effectively it can. In addition, when the content of the above-mentioned flux is above the above-mentioned lower limit, the addition effect of the flux is more effectively exhibited. When the content of the flux is less than or equal to the upper limit, the hygroscopicity of the cured product is further reduced, and the reliability of the connection structure is further enhanced.

(Conductive particles)
The conductive particles are not particularly limited as long as at least the conductive outer surface is a solder. It is preferable that the said electroconductive particle is an electroconductive particle which has a base material particle and a conductive layer arrange | positioned on the surface of this base material particle, and at least the outer surface of this conductive layer is a solder layer. Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, metal particles and the like. The substrate particles may be core-shell particles. The substrate particles are preferably substrate particles that are not metal particles, and more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic hybrid particles. The base particle is preferably a resin particle formed of a resin. When connecting between the electrodes, the conductive particles are generally compressed after the conductive particles are disposed between the electrodes. When the substrate particles are resin particles, the conductive particles are easily deformed by compression, and the contact area between the conductive particles and the electrode becomes large. Therefore, the conduction reliability between the electrodes can be enhanced. From the viewpoint of further enhancing the thermal shock resistance property of the connection structure, the conductive particle has a resin particle and a conductive layer disposed on the surface of the resin particle, and at least the outer surface of the conductive layer is a solder. It is preferable that it is a conductive particle which is a layer.

  In FIG. 1, the electroconductive particle contained in the electrically-conductive material which concerns on one Embodiment of this invention is shown typically by sectional drawing.

  The conductive particle 1 shown in FIG. 1 has a resin particle 2 and a conductive layer 3 disposed on the surface 2 a of the resin particle 2. The conductive layer 3 covers the surface 2 a of the resin particle 2. The conductive particle 1 is a coated particle in which the surface 2 a of the resin particle 2 is coated with the conductive layer 3. Therefore, the conductive particles 1 have the conductive layer 3 on the surface 1a.

  The conductive layer 3 includes a first conductive layer 4 disposed on the surface 2 a of the resin particle 2 and a solder layer 5 (second conductive layer) disposed on the surface 4 a of the first conductive layer 4. Have. The outer surface layer of the conductive layer 3 is the solder layer 5. Therefore, conductive particle 1 has solder layer 5 as a part of conductive layer 3 (conductive part), and further, as a part of conductive layer 3 (conductive part) between resin particle 2 and solder layer 5 The first conductive layer 4 is provided separately from the solder layer 5. Thus, the conductive layer 3 may have a multilayer structure, or may have a multilayer structure of two or more layers.

  As described above, the conductive layer 3 has a two-layer structure. As in the modification shown in FIG. 2, the conductive particles 11 may have the solder layer 12 as a single layer conductive layer. At least the outer surface of the conductive portion in the conductive particle may be a solder, and for example, at least the outer surface layer of the conductive layer in the conductive particle is preferably a solder layer. However, among the conductive particles 1 and the conductive particles 11, the conductive particles 1 are preferable because production of the conductive particles is easy. Further, as in the modification shown in FIG. 3, solder particles 16 which do not have base particles in the core and are not core-shell particles may be used. The solder particles 16 are formed of solder at both the central portion and the outer surface. However, among the conductive particles 1, the conductive particles 11 and the solder particles 16, the conductive particles 1 and the conductive particles 11 are preferable.

  The conductive particles are more preferably solder particles. When the conductive particles are solder particles, conductivity and moist heat resistance can be enhanced, and the adhesion between the cured product and the object to be bonded by the cured product can be further enhanced.

  Various organic substances are suitably used as the resin for forming the above-mentioned resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; Alkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene Oxide, polyacetal, polyimide, polyamide imide, polyether ether Tons, polyethersulfone, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. A resin for forming the above-mentioned resin particles can be designed because resin particles having arbitrary compression physical properties suitable for the conductive material can be designed and synthesized, and the hardness of the substrate particles can be easily controlled to a suitable range. The polymer is preferably a polymer obtained by polymerizing one or two or more polymerizable monomers having a plurality of ethylenic unsaturated groups.

  When the resin particle is obtained by polymerizing a monomer having an ethylenically unsaturated group, as the monomer having an ethylenically unsaturated group, a non-crosslinkable monomer and a crosslinkable monomer Can be mentioned.

  Examples of the non-crosslinkable monomers include styrene-based monomers such as styrene and α-methylstyrene; carboxyl-containing monomers such as (meth) acrylic acid, maleic acid and maleic anhydride; methyl ( Meta) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylates such as meta) acrylate and isobornyl (meth) acrylate; oxygen such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate (Meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate and vinyl stearate Esters; unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; trifluoromethyl (meth) acrylates, pentafluoroethyl (meth) acrylates, halogen-containing monomers such as vinyl chloride, vinyl fluoride and chlorostyrene, etc. Can be mentioned.

  Examples of the crosslinkable monomer include, for example, tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipentamer. Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Multifunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanurets And silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, .gamma .- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. Be

  The said resin particle can be obtained by polymerizing the polymerizable monomer which has the said ethylenically unsaturated group by a well-known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of swelling and polymerizing a monomer with a radical polymerization initiator using non-crosslinked seed particles.

  When the substrate particles are inorganic particles or organic-inorganic hybrid particles other than metal particles, examples of the inorganic substance for forming the substrate particles include silica and carbon black. Preferably, the mineral is not a metal. The particles formed of the above silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, baking is carried out as necessary. The particles obtained by carrying out are mentioned. As said organic-inorganic hybrid particle | grains, the organic-inorganic hybrid particle | grains etc. which were formed, for example by bridge | crosslinking alkoxy silyl polymer and acrylic resin are mentioned.

  When the base particle is a metal particle, examples of the metal for forming the metal particle include silver, copper, nickel, silicon, gold and titanium. However, it is preferable that the said base material particle is not a metal particle.

  The average particle diameter of the base particle is preferably 1 μm or more, more preferably 2 μm or more, preferably 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, particularly preferably 5 μm or less. The conduction reliability between the electrodes is further enhanced when the average particle size of the substrate particles is equal to or more than the above lower limit. The space | interval between electrodes can be narrowed as the average particle diameter of a substrate particle is below the said upper limit.

  The method of forming a conductive layer on the surface of the substrate particle, and the method of forming a solder layer on the surface of the substrate particle or the surface of the first conductive layer are not particularly limited. The conductive layer and the solder layer may be formed by, for example, a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, And a method of coating a metal powder or a paste containing a metal powder and a binder on the surface of a substrate particle, and the like. Among them, a method by electroless plating, electroplating or physical collision is preferable. Examples of the method by physical vapor deposition include methods such as vacuum deposition, ion plating and ion sputtering. Further, in the method based on the physical collision, for example, a theta composer (manufactured by Tokuju Craft Co., Ltd.) or the like is used.

  The method of forming the solder layer on the surface of the base particle or the first conductive layer is preferably a method by physical collision. The solder layer is preferably disposed on the surface of the base particle or the first conductive layer by physical impact.

  It is preferable that the material which comprises the said solder (solder layer) is a filler material whose liquidus line is 450 degrees C or less based on JISZ3001: welding term. Examples of the composition of the solder include metal compositions containing zinc, gold, lead, copper, tin, bismuth, indium and the like. Among these, a tin-indium-based (117 ° C. eutectic) that is low in melting point and lead free, or a tin-bismuth-based (139 ° C. eutectic) is preferable. That is, the solder is preferably free of lead, and is preferably a solder containing tin and indium, or a solder containing tin and bismuth.

  The melting point of the above solder (solder layer) is preferably 80 ° C. or more, more preferably 100 ° C. or more, preferably 200 ° C. or less, more preferably 160 ° C. or less, still more preferably 150 ° C. or less, still more preferably 140 ° C. or less It is. The melting point of the solder (solder layer) is more preferably 100 ° C. or more and 140 ° C. or less.

  In order to further increase the bonding strength between the solder (solder layer) and the electrode, the solder is nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese And metals such as chromium, tungsten, molybdenum and palladium. From the viewpoint of further enhancing the bonding strength between the solder and the electrode, the solder preferably contains nickel, copper, antimony, aluminum or zinc. From the viewpoint of further enhancing the bonding strength between the solder and the electrode, the content of these metals for enhancing the bonding strength is preferably 0.0001% by weight or more, preferably 100% by weight of the solder (solder layer). Is less than 1% by weight.

  The conductive particle has a substrate particle and a conductive layer disposed on the surface of the substrate particle, and the outer surface of the conductive layer is a solder layer, the substrate particle and the solder layer Preferably, the first conductive layer is provided separately from the solder layer. In this case, the solder layer is a part of the entire conductive layer, and the first conductive layer is a part of the entire conductive layer.

  The first conductive layer other than the solder layer preferably contains a metal. The metal constituting the first conductive layer is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, tungsten, molybdenum and cadmium, and alloys of these, etc. Can be mentioned. Alternatively, tin-doped indium oxide (ITO) may be used as the metal. The metal may be used alone or in combination of two or more.

  The first conductive layer is preferably a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer or a gold layer, and still more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer or a gold layer, and still more preferably a copper layer. By using conductive particles having these preferred conductive layers for connection between electrodes, connection resistance between the electrodes is further reduced. In addition, a solder layer can be more easily formed on the surface of these preferred conductive layers. The first conductive layer may be a solder layer. The conductive particles may have a plurality of solder layers.

  Conventionally, the particle diameter of conductive particles having a solder layer on the outer surface layer of the conductive layer has been about several hundred μm. This is because even if it is going to obtain conductive particles whose particle diameter is several tens of μm and whose surface layer is a solder layer, the solder layer can not be formed uniformly. On the other hand, when the solder layer is formed by optimizing the dispersion conditions at the time of electroless plating, the conductive particles have a particle diameter of several tens of μm, in particular, a particle diameter of 0.1 μm to 50 μm. Even when obtaining the conductive particles, the solder layer can be uniformly formed on the surface of the first conductive layer. Further, by using the theta composer, even when conductive particles having a particle diameter of 50 μm or less are obtained, a solder layer can be uniformly formed on the surface of the first conductive layer.

  The content of tin is preferably less than 90% by weight, more preferably 85% by weight or less, based on 100% by weight of the solder and the solder layer. In addition, the content of tin in 100 wt% of the solder and the solder layer is appropriately determined in consideration of the melting point of the solder and the solder layer, and the like. The content of tin in 100% by weight of the solder and the solder layer is preferably 5% by weight or more, more preferably 10% by weight or more, and still more preferably 20% by weight or more.

  The thickness of each of the first conductive layer and the solder layer is preferably 10 nm or more, more preferably 50 nm or more, still more preferably 100 nm or more, preferably 2000 nm or less, more preferably 1000 nm or less. Conductivity becomes high enough that the thickness of a 1st conductive layer and a solder layer is more than the said minimum. When the thickness of the first conductive layer and the solder layer is not more than the above upper limit, the difference in thermal expansion coefficient between the substrate particles and the first conductive layer and the solder layer becomes small, and the first conductive layer and the solder layer Peeling is less likely to occur.

  The first conductive layer may have a laminated structure of two or more layers. When the first conductive layer has a laminated structure of two or more layers, the thickness of the outermost layer in the first conductive layer is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 25 nm or more, particularly preferably Is 50 nm or more, preferably 1000 nm or less, more preferably 500 nm or less. When the thickness of the outermost layer in the first conductive layer is equal to or more than the above lower limit, the conductivity becomes sufficiently high. When the thickness of the outermost layer in the first conductive layer is less than or equal to the above upper limit, the difference in the coefficient of thermal expansion between the substrate particles and the outermost layer of the first conductive layer decreases, and the outermost layer in the first conductive layer Peeling is less likely to occur.

  The average particle diameter of the conductive particles is preferably 0.1 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 80 μm or less, still more preferably 50 μm or less, particularly preferably 40 μm or less. When the average particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrode is sufficiently large, and conductive particles aggregated when forming the conductive layer are formed. It becomes difficult. In addition, the size of the conductive material is suitable for the conductive particles, the distance between the electrodes connected via the conductive particles is not too large, and the conductive layer does not easily peel off from the surface of the base particle.

  The said resin particle can be used properly according to the electrode size or land diameter of the board | substrate to mount.

  The ratio of the average particle size C of the conductive particles to the average particle size A of the resin particles of the conductive particles is more preferable from the viewpoint of connecting the upper and lower electrodes more reliably and further suppressing the short circuit between the electrodes adjacent in the lateral direction. C / A) is more than 1.0, preferably 3.0 or less. Further, when the first conductive layer is present between the resin particles and the solder layer, the ratio of the average particle diameter B of the conductive particle portion excluding the solder layer to the average particle diameter A of the resin particles (B / A) is more than 1.0, preferably 2.0 or less. Furthermore, when the first conductive layer is present between the resin particles and the solder layer, the average particle size B of the conductive particle portion excluding the solder layer of the average particle size C of the conductive particles including the solder layer The ratio (C / B) to is greater than 1.0, preferably less than or equal to 2.0. When the above ratio (B / A) is within the above range or the above ratio (C / B) is within the above range, it is possible to more reliably connect the upper and lower electrodes and to horizontally adjacent electrodes. Short circuit between them can be further suppressed.

Conductive materials for FOB and FOF applications:
The conductive material according to the present invention is suitably used for connection between a flexible printed substrate and a glass epoxy substrate (FOB (Film on Board)), or for connection between a flexible printed substrate and a flexible printed substrate (FOF (Film on Film)). Be

  For FOB and FOF applications, the L & S, which is the dimension of the part with electrode (line) and the part without electrode (space), is generally 100 to 500 μm. The average particle size of resin particles used in FOB and FOF applications is preferably 10 to 100 μm. When the average particle diameter of the resin particles is 10 μm or more, the thickness of the conductive material and the connection portion disposed between the electrodes is sufficiently thick, and the adhesion is further enhanced. When the average particle diameter of the resin particles is 100 μm or less, short circuiting between the adjacent electrodes is further less likely to occur.

Conductive materials for flip chip applications:
The conductive material according to the present invention is suitably used for flip chip applications.

  In flip chip applications, the land diameter is generally 15 to 80 μm. The average particle size of resin particles used in flip chip applications is preferably 1 to 15 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be made sufficiently thick, and the electrodes can be more reliably electrically connected. it can. When the average particle size of the resin particles is 15 μm or less, short circuiting between the adjacent electrodes is further less likely to occur.

Conductive materials for COF:
The conductive material according to the present invention is suitably used for connection (COF (Chip on Film)) between a semiconductor chip and a flexible printed circuit.

  For COF applications, the L & S, which is the dimension of the part with electrode (line) and the part without electrode (space), is generally 10 to 50 μm. The average particle diameter of the resin particles used in the COF application is preferably 1 to 10 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be made sufficiently thick, and the electrodes can be more reliably electrically connected. it can. If the average particle size of the resin particles is 10 μm or less, short circuiting between the adjacent electrodes becomes even more difficult.

  The “average particle diameter” of the base particles (the resin particles and the like) and the conductive particles indicates a number average particle diameter. The average particle diameter of the substrate particles (resin particles and the like) and the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

  The content of the conductive particles is preferably 3% by weight or more, and preferably 40% by weight or less in 100% by weight of the conductive material. The conductive property and the insulating property can be compatible at a still higher level when performing anisotropic conductive connection when the content of the conductive particles is 3% by weight or more and 40% by weight or less . The content of the conductive particles is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 15% by weight or more, preferably 35% by weight or less, in 100% by weight of the conductive material. It is 30% by weight or less. When the content of the conductive particles in 100% by weight of the conductive material is not less than the lower limit and not more than the upper limit, conductive particles can be easily disposed between the upper and lower electrodes to be connected. Furthermore, it becomes difficult to electrically connect between adjacent electrodes which should not be connected via a plurality of conductive particles. That is, a short circuit between adjacent electrodes can be further prevented.

(Other ingredients)
The conductive material preferably contains a filler. The use of the filler can suppress the coefficient of thermal expansion of the cured product of the conductive material. Specific examples of the filler include silica, aluminum nitride, alumina, glass, boron nitride, silicon nitride, silicone, carbon, graphite, graphene and talc. Only one filler may be used, or two or more fillers may be used in combination. When the filler having a high thermal conductivity is used, the main curing time is shortened.

  The conductive material may contain a solvent. By using the solvent, the viscosity of the conductive material can be easily adjusted. Examples of the solvent include ethyl acetate, methyl cellosolve, toluene, acetone, methyl ethyl ketone, cyclohexane, n-hexane, tetrahydrofuran and diethyl ether.

  From the viewpoint of further enhancing the adhesion reliability of the object to be adhered, the conductive material preferably contains an adhesion promoter. As the above-mentioned adhesion grant agent, a coupling agent, a flexible material, etc. are mentioned. The adhesion promoter may be used alone or in combination of two or more.

  In 100% by weight of the conductive material, the content of the adhesion promoter is preferably 0.1% by weight or more, more preferably 1% by weight or more, preferably 10% by weight or less, and more preferably 5% by weight or less. The adhesion reliability of an adhesion subject becomes it still higher that content of the above-mentioned adhesion grant agent is more than the above-mentioned lower limit and below the above-mentioned upper limit.

(Details and application of conductive material)
The conductive material according to the present invention is a paste-like or film-like conductive material, and is preferably a paste-like conductive material. The paste-like conductive material is a conductive paste. The film-like conductive material is a conductive film. When the conductive material is a conductive film, a film not containing conductive particles may be laminated to the conductive film containing conductive particles. The conductive material according to the present invention is preferably an anisotropic conductive material. The conductive material according to the present invention is preferably used for connection between electrodes, preferably a circuit connection material, and more preferably a circuit connection material used for electrical connection between electrodes.

  The conductive material according to the present invention is preferably a conductive paste, and is preferably a conductive paste applied on the connection target member in a paste state.

  The viscosity at 25 ° C. of the conductive paste is preferably 3 Pa · s or more, more preferably 5 Pa · s or more, preferably 600 Pa · s or less, more preferably 400 Pa · s or less. Sedimentation of the conductive particles in the conductive paste can be suppressed as the viscosity is at least the lower limit. The dispersibility of a conductive particle becomes it still higher that the said viscosity is below the said upper limit. If the viscosity of the conductive paste before application is within the above range, the flow of the conductive paste before curing can be further suppressed after applying the conductive paste on the first connection target member, and the voids are further enhanced. It becomes difficult to occur. In addition, the liquid form is included in the paste form.

  The conductive material according to the present invention is preferably a conductive material used to connect a connection target member having a copper electrode. When a connection target member having a copper electrode is connected using a conductive material, there is a problem that migration easily occurs due to the copper electrode in the connection structure. On the other hand, by using the conductive material according to the present invention, even if the connection target member having a copper electrode is connected, the migration in the connection structure can be effectively suppressed, and the insulation reliability can be effectively improved. it can.

  The conductive material according to the present invention can be used to bond various connection target members. The conductive material is suitably used to obtain a connection structure in which the first and second connection target members are electrically connected.

  A connection structure according to the present invention includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, and the first and second connection targets. And a connection portion connecting the members, wherein the connection portion is formed of the above-described conductive material, and the first electrode and the second electrode are electrically connected by the conductive particles. ing.

  In FIG. 4, the connection structure using the electrically-conductive material which concerns on one Embodiment of this invention is typically shown with front sectional drawing.

  The connection structure 21 illustrated in FIG. 4 is a connection portion that electrically connects the first connection target member 22, the second connection target member 23, and the first and second connection target members 22 and 23. And 24. The first connection target member 22 and the second connection target member 23 are electronic components. The connection portion 24 is formed of a conductive material including the conductive particle 1. In FIG. 4, the conductive particles 1 are schematically shown for convenience of illustration.

  The first connection target member 22 has a plurality of first electrodes 22 b on the surface 22 a (upper surface). The second connection target member 23 has a plurality of second electrodes 23 b on the surface 23 a (lower surface). The first electrode 22 b and the second electrode 23 b are electrically connected by one or more conductive particles 1. Therefore, the first and second connection target members 22 and 23 are electrically connected by the conductive particles 1.

The manufacturing method of the said connection structure is not specifically limited. As an example of the manufacturing method of the connection structure, the conductive material is disposed between the first connection target member and the second connection target member, and after obtaining a laminate, the laminate is heated. And a method of applying pressure. By heating and pressing, the solder layer of the conductive particles 1 melts, and the electrodes are electrically connected by the conductive particles 1. Furthermore, when the binder resin contains a thermosetting compound, the binder resin is cured, and the first and second connection target members 22 and 23 are connected by the cured binder resin. The pressure of the said pressurization is about 9.8 * 10 < ⁴ > -4.9 * 10 < ⁶ > Pa. The temperature of the heating is about 120 to 220 ° C.

  FIG. 5 is an enlarged schematic cross-sectional view of the connection portion between the conductive particle 1 and the first and second electrodes 22b and 23b in the connection structure 21 shown in FIG. As shown in FIG. 5, in the connection structure 21, the solder layer portion 5 a of the conductive particle 1 is melted by heating and pressing the laminate, and then the melted solder layer portion 5 a is the first and second portions. It fully contacts the electrodes 22b and 23b. That is, by using the conductive particles 1 whose surface layer is the solder layer 5, the conductive particles are compared to the case where the surface layer of the conductive layer is a conductive particle which is a metal such as nickel, gold or copper. The contact area between the electrode 1 and the electrodes 22b and 23b is increased. For this reason, the conduction reliability of the connection structure 21 is enhanced. Generally, the flux is gradually inactivated by heating.

  The first and second connection target members are not particularly limited as long as they are electronic components. Specifically, the first and second connection target members include electronic components such as a semiconductor chip, a capacitor, and a diode, and electronic components such as a printed circuit board, a flexible printed circuit, and a circuit board such as a glass epoxy substrate and a glass substrate. Parts etc. are mentioned. The conductive material is preferably a conductive material used to connect electronic components. The conductive material according to the present invention is preferably used for the electrical connection of the electrodes of the electronic component.

  In the connection structure, 1/5 or more of the total area of the connection portion between the connection portion and the first connection target member and the connection portion between the connection portion and the second connection target member is It is preferable to be connected by components other than the conductive particles contained in the conductive material. In other words, in the connection structure, one-fifth of the total area of the connection portion between the connection portion and the first connection target member and the connection portion between the connection portion and the second connection target member Preferably, less than one is connected by conductive particles contained in the conductive material. In this case, the thermal shock resistance of the connection structure is further enhanced.

  As an electrode provided in the said connection object member, metal electrodes, such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a molybdenum electrode, a tungsten electrode, etc. are mentioned. When the connection target member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient, and the electrode by which the aluminum layer was laminated | stacked on the surface of a metal oxide layer may be sufficient. As a material of the said metal oxide layer, the indium oxide in which the trivalent metal element was doped, the zinc oxide in which the trivalent metal element was doped, etc. are mentioned. Sn, Al, Ga, etc. are mentioned as said trivalent metal element.

  Preferably, at least one of the first electrode and the second electrode is a copper electrode. It is preferable that both the first electrode and the second electrode be copper electrodes. In this case, the flux effect by the conductive material according to the present invention is further obtained, and the conduction reliability in the connection structure is further enhanced.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples. The invention is not limited to the following examples.

The following materials were used in Examples , Reference Examples, and Comparative Examples.

(A mixture of a curable compound and (meth) acrylic acid)
(1) Synthesis of first reaction product of bisphenol F and 1,6-hexanediol diglycidyl ether:
72 parts by weight of bisphenol F (containing 4,4′-methylenebisphenol, 2,4′-methylenebisphenol and 2,2′-methylenebisphenol in a weight ratio of 31:52:17), 1,6-hexanediol di 100 parts by weight of glycidyl ether and 1 part by weight of triphenylphosphine were placed in a three-necked flask and dissolved at 150 ° C. Thereafter, addition polymerization was performed at 180 ° C. for 6 hours to obtain a first reaction product.

  It is confirmed that the addition polymerization reaction has progressed, and the first reactant has a structural unit in which a skeleton derived from bisphenol F and a skeleton derived from 1,6-hexanediol diglycidyl ether are bonded to the main chain. It was confirmed that the resin had epoxy groups derived from 1,6-hexanediol diglycidyl ether at both ends.

  100 parts by weight of the obtained first reactant and 4 parts by weight of acrylic acid were mixed, and the temperature was raised to 80.degree. After raising the temperature, 0.1 parts by weight of tetra-n-butylsulfonium bromide which is a reaction catalyst of epoxy group and carboxyl group is added, and condensation reaction is carried out for 4 hours to make 100% of epoxy groups at both ends. The compound 2 which the carboxyl group reacted was obtained. The weight average molecular weight of the epoxy compound obtained by GPC was 8,000.

  The obtained compound 2 was coated on a PET film so as to have a thickness of about 100 μm, and vacuum dried at 60 ° C. for 24 hours under 100 Pa pressure reduction to remove acrylic acid. The residual amount of acrylic acid was measured by NMR and found to be 0.01% by weight.

  A compound 3 having a methacryl group at both ends was obtained in the same manner except that methacrylic acid was reacted with the first reactant. Similarly, the residual amount of mecrylic acid was measured by NMR and found to be 0.01% by weight.

(Curable compound)
Bisphenol F type epoxy compound (manufactured by DIC "EXA 830-CRP")

((Meth) acrylic acid)
Acrylic acid Methacrylic acid

(Photo radical curing agent)
Photo radical curing agent ("IRGACURE 651" manufactured by BASF Japan Ltd.)

(Hardening agent)
Curing agent 1 ("HXA-3921HP" manufactured by Asahi Kasei E-Materials Co., Ltd.)
Hardening agent 2 (manufactured by Nippon Soda Co., Ltd. "TEP-2E4MZ")

(flux)
Glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.)
Adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.)

(Conductive particles)
Conductive particles A: conductive particles A having a metal layer in which a nickel plating layer is formed on the surface of divinylbenzene resin particles and a gold plating layer is formed on the surface of the nickel plating layer (average particle diameter 15 μm )
Conductive particle B: conductive particle B in which a copper layer is formed on the surface of divinylbenzene resin particles, and a solder layer is formed on the surface of the copper layer

[Method of producing conductive particle B]
Electroless nickel plating was performed on divinyl benzene resin particles ("Micropearl SP-210" manufactured by Sekisui Chemical Co., Ltd.) having an average particle diameter of 10 μm to form a base nickel plating layer with a thickness of 0.1 μm on the surface of the resin particles. Subsequently, the resin particle in which the base nickel plating layer was formed was electrolytically copper-plated, and the 1-micrometer-thick copper layer was formed. Furthermore, it electroplated using the electroplating solution containing tin and bismuth, and formed the 1-micrometer-thick solder layer. Thus, a 1 μm thick copper layer is formed on the surface of the resin particle, and a 1 μm thick solder layer (tin: bismuth = 43% by weight: 57% by weight) is formed on the surface of the copper layer Conductive particles B were produced.

  Conductive particles C: SnBi solder particles ("DS-10" manufactured by Mitsui Mining & Smelting Co., Ltd., average particle diameter (median diameter) 12 μm)

(Other ingredients)
Adhesion promoter (Shin-Etsu Chemical "KBE-403")

(Examples 2 to 12, 14; Reference Examples 1 and 13 and Comparative Examples 1 and 2)
The components shown in Table 1 below were blended in the amounts shown in Table 1 below to obtain an anisotropic conductive paste.

(Preparation of connection structure)
A glass epoxy substrate (FR-4 substrate) having a copper electrode pattern (copper electrode thickness: 10 μm) with L / S of 100 μm / 100 μm on the top was prepared. In addition, a flexible printed board having a copper electrode pattern (copper electrode thickness 10 μm) with L / S of 100 μm / 100 μm on the lower surface was prepared.

  The obtained anisotropic conductive paste was coated on the upper surface of the glass epoxy substrate to a thickness of 200 μm to form an anisotropic conductive paste layer. Next, it irradiated with UV for 10 seconds on the conditions of 200 mW in wavelength 365nm with LED-UV irradiator, and B-staged the anisotropic conductive paste. Next, on the upper surface of the anisotropic conductive paste layer which was B-staged and the curing progressed, the flexible printed circuit was laminated such that the electrodes faced each other. Thereafter, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer is 185 ° C., the pressure heating head is placed on the upper surface of the flexible printed board, and a pressure of 2.0 MPa is applied to the anisotropy. The conductive paste layer was fully cured at 185 ° C. to obtain a connection structure.

(Evaluation)
(1) Acid value The acid value was determined in accordance with ISO 6618-1997.

  1 g of the obtained anisotropic conductive paste and 30 g of pure water were stirred and mixed at 2000 rpm for 3 minutes using a planetary stirrer. The acid value was determined by titrating the supernatant with the indicator phenolphthalein using a 0.05 N KOH aqueous solution.

(2) Storage stability Using an E-type viscosity measuring device (“VISCOMETER TV-22” manufactured by TOKI SANGYO CO. LTD., Using rotor: φ 15 mm, temperature: 25 ° C.), the viscosity η 1 (rotational conductivity) of the anisotropic conductive paste The number 5 rpm) was measured. Similarly, the viscosity η2 of the anisotropic conductive paste after standing for 3 days at 25 ° C. was measured in the same manner as the viscosity η1. Storage stability was determined according to the following criteria.

[Criteria for storage stability]
○○: 22 / η1 less than 1.3 ○: 22 // 1 η1.3 or more and less than 1.5 ×: η2 / η1 1.51.5 or more

(3) Conduction test The connection resistance between the upper and lower electrodes of the obtained connection structure was measured by the four-terminal method. The average value of two connection resistances was calculated. The connection resistance can be determined from the relationship of voltage = current × resistance by measuring the voltage when a constant current flows. The continuity test between the upper and lower electrodes was determined according to the following criteria.

[Criteria for continuity test]
○○: average value of connection resistance is 8.0Ω or less ○: average value of connection resistance is more than 8.0Ω, 10.0Ω or less Δ: average value of connection resistance is more than 10.0Ω, 15.0Ω or less × : Average value of connection resistance exceeds 15.0 Ω

(4) Conduction test after the moisture resistance test After leaving the obtained connection structure at 85 ° C. and 85% humidity atmosphere for 1000 hours, the conduction test was evaluated in the same manner as the evaluation of the above (3) conduction test. . The continuity test after the moisture resistance test was judged according to the following criteria.

[Criteria for continuity test after moisture resistance test]
○○: average value of connection resistance is 8.0Ω or less ○: average value of connection resistance is more than 8.0Ω, 10.0Ω or less Δ: average value of connection resistance is more than 10.0Ω, 15.0Ω or less × : Average value of connection resistance exceeds 15.0 Ω

(5) Adhesive Strength In the connection structure thus obtained, 90 ° peel adhesive strength was measured with an automatic tensile tester at a tensile speed of 10 (mm / min) and an atmosphere of 23 ° C.

[Criteria for adhesion]
○ ○: adhesive strength is 15 N / cm or more ○: adhesive strength is 10 N / cm or more and less than 15 N / cm Δ: adhesive strength is 5 N / cm or more and less than 10 N / cm ×: adhesion is less than 5 N / cm

(6) Adhesion after moisture resistance test The obtained connection structure was left to stand at 85 ° C. and 85% humidity for 1000 hours, and then the adhesion was evaluated in the same manner as the evaluation of (5) adhesion above. . The adhesion after the moisture resistance test was judged according to the following criteria.

[Criteria for adhesion after moisture resistance test]
○ ○: adhesive strength is 15 N / cm or more ○: adhesive strength is 10 N / cm or more and less than 15 N / cm Δ: adhesive strength is 5 N / cm or more and less than 10 N / cm ×: adhesion is less than 5 N / cm

  The composition and the results are shown in Table 1 below.

Note that (3) of the continuity test evaluation results of Examples 4, 14 and Reference Example 13, but both are "○○", connection resistance than that of Example 1 4 and Reference Examples 13 towards the Example 4 Was low. Moreover, although the evaluation result of the continuity test after (4) moisture resistance test of Example 4, 14 and the reference example 13 is all "(circle) (circle)", the direction of Example 4 is Example 14 and the reference example 13 The connection resistance after the moisture resistance test was lower than that. Furthermore, (5) adhesion evaluation results of Examples 4, 14 and Reference Example 13, but both are "○○", adhesion than is Example 1 4 and Reference Examples 13 towards the Example 4 The power was high. Furthermore, although the evaluation result of the adhesive force after (6) moisture resistance test of Example 4, 14 and the reference example 13 is all "(circle) (circle)", the direction of Example 4 is Example 14 and the reference example 13 The adhesion after the moisture resistance test was higher than that.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle 1a ... Surface 2 ... Resin particle 2a ... Surface 3 ... Conductive layer 4 ... 1st conductive layer 4a ... Surface 5 ... Solder layer 5a ... Melted solder layer part 11 ... Conductive particle 12 ... Solder layer 16 ... solder particles 21 ... connection structure 22 ... first connection target member 22a ... surface 22b ... first electrode 23 ... second connection target member 23a ... surface 23b ... second electrode 24 ... connection portion

Claims (5)

And at least an electrically conductive outer surface comprising a conductive particle of solder, a curable compound, a curing agent, and (meth) acrylic acid,
Epoxy (meth) acrylate is included as the curable compound,
The electrically conductive material whose content of the said (meth) acrylic acid in 100 weight% of electrically conductive materials is 0.0001 weight% or more and 0.1 weight% or less.   The conductive material according to claim 1, wherein a content of the (meth) acrylic acid in 100 wt% of the conductive material is 0.05 wt% or less.   The electrically conductive material of Claim 1 or 2 whose content of the said (meth) acrylic acid in 100 weight% of electrically conductive materials is 0.005 weight% or more. The conductive material according to any one of claims 1 to 3 , which is a circuit connection material used for electrical connection between electrodes. A first connection target member having a first electrode on the surface;
A second connection target member having a second electrode on its surface;
A connecting portion connecting the first connection target member and the second connection target member;
The said connection part is formed of the electrically-conductive material of any one of Claims 1-4 ,
The connection structure which the said 1st electrode and the said 2nd electrode are electrically connected by the said electroconductive particle.

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