TW202020085A - Conductive material and connection structure - Google Patents

Abstract

Provided is a conductive material, the storage stability of which can be efficiently increased and which can be densely filled with flux, and which can also efficiently increase solder coalescing properties during conductive connection. This conductive material comprises a plurality of conductive particles having solder on the outer surface portions of conductive parts, a thermosetting component, and flux, wherein the flux contains solid salt of a first compound having a carboxyl group and a second compound having an amino group, and a liquid compound which is a reactant of a third compound having a carboxyl group and a fourth compound having an amino group.

Description

Conductive materials and connecting structures

The present invention relates to a conductive material containing conductive particles having solder on the outer surface portion of the conductive portion. In addition, the present invention relates to a connection structure using the conductive material.

It is well known that there are anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film. The aforementioned anisotropic conductive material has conductive particles dispersed in a binder.

The aforementioned anisotropic conductive material is used to obtain various connection structures. Examples of the connection using the above-mentioned anisotropic conductive material include: a connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass)), and a connection between a semiconductor wafer and a flexible printed substrate (COF (Chip on Film, wafer on film)), semiconductor wafer and glass substrate (COG (Chip on Glass, glass on glass)), and flexible printed circuit board and glass epoxy substrate (FOB (Film on Board , Film on board)) etc.

When the electrodes of the flexible printed substrate and the electrode of the glass epoxy substrate are electrically connected by the anisotropic conductive material, for example, an anisotropic conductive material containing conductive particles is arranged on the glass epoxy substrate. Next, the flexible printed circuit board is laminated and heated and pressurized. By this, the anisotropic conductive material is hardened and the electrodes are electrically connected via the conductive particles, thereby obtaining a connection structure.

As an example of the above-mentioned anisotropic conductive material, the following Patent Document 1 discloses a conductive adhesive composition comprising: (A) conductive particles containing a metal having a melting point of 220°C or lower, (B) heat Curable resin, and (C) flux activator. In the above conductive adhesive composition, the average particle diameter of the (C) flux active agent is 10 μm or less. [Prior Technical Literature] [Patent Literature]

[Patent Literature 1] WO2012/102077A1

[Problems to be solved by the invention]

Regarding the previous conductive materials, there are cases where the moving speed of the conductive particles on the electrode (wire) is relatively slow, making it difficult for the solder to efficiently condense between the upper and lower electrodes that should be connected. As a result, it is easy to reduce the conduction reliability and insulation reliability between the electrodes.

As a method for efficiently condensing the solder on the electrode, a method of increasing the amount of flux in the conductive material and the like can be mentioned. As the above-mentioned fluxes, there are solid fluxes that are solid when the conductive material is formulated and liquid fluxes that are liquid when the conductive material is formulated.

However, the inventors of the present invention found that the solid flux and the liquid flux have the following problems.

In the case of using only solid flux, if the content of the solid flux in the conductive material is increased, the viscosity of the conductive material may be greatly increased, making it difficult to use it as a conductive material. It is difficult to fill the conductive material with solid flux, and it is difficult to efficiently aggregate the solder on the electrode. In addition, since the solid flux has low reactivity with the thermosetting compound in the conductive material, the storage stability of the conductive material can be improved. As a result, in the case where only solid flux is used for the conductive material, although the storage stability of the conductive material can be improved, it is difficult to fill the solid flux highly, and it is difficult to improve the cohesiveness of the solder.

In addition, when only liquid flux is used, if the content of liquid flux in the conductive material is increased, the flux may react with the thermosetting compound in the conductive material, resulting in a decrease in the storage stability of the conductive material . In addition, the liquid flux can be highly filled into the conductive material, which can effectively condense the solder on the electrode. As a result, when only liquid flux is used for the conductive material, although the liquid flux can be highly filled and the cohesion of the solder is improved, it is difficult to improve the storage stability of the conductive material.

The previous conductive materials are difficult to meet all the requirements of improving the storage stability of the conductive materials, high filling of flux in the conductive materials, and improving the cohesion of the solder during conductive connection.

The purpose of the present invention is to provide a conductive material, which can effectively improve the storage stability of the conductive material, can be highly filled with flux in the conductive material, and can effectively improve the cohesion of the solder during conductive connection. In addition, an object of the present invention is to provide a connection structure using the conductive material. [Technical means to solve the problem]

According to a broad aspect of the present invention, there is provided a conductive material including a plurality of conductive particles having solder on the outer surface portion of the conductive portion, a thermosetting component, and a flux, and the flux includes the first having a carboxyl group A solid salt of a compound and a second compound having an amine group, and a liquid compound as a reactant of a third compound having a carboxyl group and a fourth compound having an amine group.

In a specific aspect of the conductive material of the present invention, the weight ratio of the content of the solid salt to the content of the liquid compound is 2 or more and 20 or less.

In a specific aspect of the conductive material of the present invention, the first compound and the third compound are the same compound.

In a specific aspect of the conductive material of the present invention, the second compound and the fourth compound are the same compound.

In a specific aspect of the conductive material of the present invention, the average particle diameter of the solid salt is 0.01 μm or more and 10 μm or less.

In a specific aspect of the conductive material of the present invention, the thermosetting component includes a thermosetting compound, and the content of the flux is 1 part by weight or more and 50 parts by weight relative to 100 parts by weight of the thermosetting compound. the following.

In a specific aspect of the conductive material of the present invention, in 100% by weight of the conductive material, the content of the flux is 0.05% by weight or more and 20% by weight or less.

In a specific aspect of the conductive material of the present invention, the average particle diameter of the conductive particles is 0.01 μm or more and 50 μm or less.

In a specific aspect of the conductive material of the present invention, the conductive material is a conductive paste.

According to a broad aspect of the present invention, there is provided a connection structure including: a first connection object member having a first electrode on a surface; a second connection object member having a second electrode on a surface; and a connection portion, It connects the first connection object member and the second connection object member; the material of the connection portion is the conductive material, and the first electrode and the second electrode are electrically connected by the conductive particles. [Effect of invention]

The conductive material of the present invention includes a plurality of conductive particles having solder on the outer surface portion of the conductive portion, thermosetting components, and flux. In the conductive material of the present invention, the flux includes a solid salt of the first compound having a carboxyl group and a second compound having an amine group, and a liquid as a reactant of the third compound having a carboxyl group and the fourth compound having an amine group Compound. Since the conductive material of the present invention has the above-mentioned structure, the storage stability of the conductive material can be effectively improved, the conductive material can be highly filled with flux, and the cohesiveness of the solder during conductive connection can be effectively improved.

Hereinafter, the details of the present invention will be described.

(Conductive material) The conductive material of the present invention includes a plurality of conductive particles having solder on the outer surface portion of the conductive portion, thermosetting components, and flux. In the conductive material of the present invention, the flux includes a solid salt of the first compound having a carboxyl group and a second compound having an amine group, and a liquid as a reactant of the third compound having a carboxyl group and the fourth compound having an amine group Compound.

Since the conductive material of the present invention has the above-mentioned structure, the storage stability of the conductive material can be effectively improved, the conductive material can be highly filled with flux, and the cohesiveness of the solder during conductive connection can be effectively improved.

Since the present invention has the above structure, when electrically connecting the electrodes, a plurality of conductive particles can be efficiently arranged on the electrodes (lines), and the solder can be efficiently aggregated between the upper and lower electrodes to be connected . In addition, it is possible to make part of the plurality of conductive particles difficult to be arranged in the region (gap) where the electrode is not formed, and significantly reduce the amount of conductive particles arranged in the region where the electrode is not formed. Therefore, the conduction reliability between the electrodes can be improved. In addition, the electrical connection between the adjacent electrodes in the lateral direction that should not be connected can be prevented, and the insulation reliability can be improved.

The flux is mainly formulated in the conductive material in order to remove oxides present on the surface of the solder and the surface of the electrode in the conductive particles, or to prevent the formation of the oxides. In the present invention, since the solid flux and the liquid flux are used together, the conductive material can be highly filled with flux. In the present invention, since the solid flux and the liquid flux are used together, compared with the case where the solid flux is used alone, it is easy to fill the conductive material with high flux. Therefore, in the present invention, the oxide present on the surface of the solder and the surface of the electrode in the conductive particles can be effectively removed, and the formation of the oxide can be effectively prevented. In the present invention, since the conductive material can be highly filled with flux, the cohesion of the solder during conductive connection can be effectively improved.

In the present invention, since the solid flux and the liquid flux are used together, the reaction between the thermosetting compound in the conductive material and the flux can be effectively suppressed. As a result, the storage stability of the conductive material can be effectively improved.

In the present invention, since the solid flux and the liquid flux are used together, compared with the case where only solid flux is used, the conductive material can be filled with high flux, and the cohesion of the solder during conductive connection can be effectively improved. In addition, in the present invention, since the solid flux and the liquid flux are used in combination, the storage stability of the conductive material can be effectively improved compared to the case where only the liquid flux is used.

Since the present invention has the above-mentioned configuration, it can meet all the requirements for improving the storage stability of the conductive material, highly filling the flux in the conductive material, and improving the cohesiveness of the solder during conductive connection.

Furthermore, in the present invention, the positional displacement between the electrodes can be prevented. In the present invention, when the first connection object member on which the conductive material is disposed on the upper surface overlaps the second connection object member, even if the alignment of the electrode of the first connection object member and the electrode of the second connection object member shifts In this state, the offset can be corrected to connect the electrodes to each other (self-alignment effect).

From the viewpoint of further filling the flux with a conductive material, and the viewpoint of more effectively improving the cohesiveness of the solder during conductive connection, the conductive material is preferably liquid at 25°C, and is preferably a conductive paste . The conductive material is preferably a conductive paste at 25°C.

From the viewpoint of further filling the flux with the conductive material, and the viewpoint of more effectively improving the cohesion of the solder during conductive connection, the viscosity (η25) of the above conductive material at 25°C is preferably 20 Pa·s The above is more preferably 30 Pa·s or more, and preferably 500 Pa·s or less, and more preferably 300 Pa·s or less. The viscosity (η25) can be appropriately adjusted by the type and amount of the ingredients.

The viscosity (η25) can be measured under the conditions of 25° C. and 5 rpm using, for example, an E-type viscometer (“TVE22L” manufactured by Toki Industry Corporation).

The above conductive material can be used in the form of conductive paste, conductive film, and the like. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. The conductive material is preferably a conductive paste from the viewpoint of further filling the conductive material with a flux and improving the cohesiveness of the solder during conductive connection. The above conductive material can be suitably used for electrical connection of electrodes. The aforementioned conductive material is preferably a circuit connection material.

Hereinafter, each component contained in the conductive material will be described. Furthermore, in this specification, "(meth)acrylic acid" means one or both of "acrylic acid" and "methacrylic acid", and "(meth)acrylate" means "acrylate" and "methacrylic acid" One or both of acrylates.

(Conductive particles) The conductive material contains conductive particles. The conductive particles electrically connect the electrodes of the connection target member. The conductive particles have solder on the outer surface portion of the conductive portion. The conductive particles may be solder particles formed of solder. The solder particles have solder on the outer surface portion of the conductive portion. The center portion of the solder particle system and the outer surface portion of the conductive portion are formed of solder. The above-mentioned solder particles are particles of solder at both the central part and the outer surface of conductivity. The conductive particles may have base particles and conductive parts arranged on the surface of the base particles. In this case, the conductive particles have solder on the outer surface portion of the conductive portion.

The conductive particles have solder on the outer surface portion of the conductive portion. The base material particles may be solder particles formed of solder. The conductive particles may be solder particles in which the base particles and the outer surface portion of the conductive portion are both solder.

Furthermore, in comparison with the case of using the above-mentioned solder particles, when using base particles that are not formed of solder and conductive particles that are provided on the surface of the base particles, the conductive particles are It is difficult to gather on the electrode. Furthermore, since the solder bonding properties of the conductive particles are low, the conductive particles moving on the electrode tend to move out of the electrode, and the effect of suppressing the positional deviation between the electrodes also tends to be low. Therefore, the conductive particles are preferably solder particles formed of solder.

Next, specific examples of conductive particles will be described with reference to the drawings.

4 is a cross-sectional view showing a first example of conductive particles that can be used for a conductive material.

The conductive particles 21 shown in FIG. 4 are solder particles. The conductive particles 21 are entirely formed of solder. The conductive particles 21 do not have base particles in the core, and are not core-shell particles. The center part of the conductive particles 21 and the outer surface part of the conductive part are formed of solder.

5 is a cross-sectional view showing a second example of conductive particles that can be used for a conductive material.

The conductive particles 31 shown in FIG. 5 include base particles 32 and conductive portions 33 arranged on the surface of the base particles 32. The conductive portion 33 covers the surface of the base particle 32. The conductive particles 31 are coated particles whose surface is coated with the conductive portion 33 on the surface of the base particle 32.

The conductive portion 33 has a second conductive portion 33A and a solder portion 33B (first conductive portion). The conductive particle 31 includes a second conductive portion 33A between the base particle 32 and the solder portion 33B. Therefore, the conductive particles 31 include the base particles 32, the second conductive portion 33A disposed on the surface of the base particles 32, and the solder portion 33B disposed on the outer surface of the second conductive portion 33A.

6 is a cross-sectional view showing a third example of conductive particles that can be used for a conductive material.

The conductive part 33 of the conductive particle 31 in FIG. 5 has a double-layer structure. The conductive particle 41 shown in FIG. 6 has a solder portion 42 as a single-layer conductive portion. The conductive particles 41 include base particles 32 and solder portions 42 arranged on the surface of the base particles 32.

Hereinafter, other details of the conductive particles will be described.

(Substrate particles) Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles other than metal particles, and more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic mixed particles. The substrate particles may be substrate particles other than inorganic particles. The base material particles may be core-shell particles having a core and a shell arranged on the surface of the core. The core may be an organic core, and the shell may be an inorganic shell.

The base material particles are further preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. By using these preferred substrate particles, the effects of the present invention can be more effectively exerted, and conductive particles more suitable for electrical connection between electrodes can be obtained.

When connecting the electrodes using the conductive particles, the conductive particles are compressed by arranging the conductive particles between the electrodes and performing pressure bonding. If the substrate particles are resin particles or organic-inorganic hybrid particles, the above-mentioned conductive particles are likely to be deformed when the above-mentioned pressure bonding is performed, and the contact area between the conductive particles and the electrode becomes larger. Therefore, the conduction reliability between the electrodes is further improved.

As the material of the above resin particles, various resins can be suitably used. Examples of the material of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; polymethyl methacrylate, Acrylic resin such as polymethyl acrylate; polyalkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin , Benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyphenol, polyphenylene ether, polyacetal, polyimide, polyimide amide imide, polyether Ether ketone, polyether ballast, divinylbenzene polymer, divinylbenzene copolymer, and polymer obtained by polymerizing one or more types of polymerizable monomers having ethylenically unsaturated groups . Examples of the divinylbenzene-based copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylate copolymer.

In view of being able to design and synthesize resin particles having arbitrary compression characteristics suitable for conductive materials, and the hardness of the resin particles can be easily controlled in a suitable range, the material of the resin particles is preferably one or more than two kinds It is a polymer obtained by polymerizing a plurality of polymerizable monomers having ethylenic unsaturated groups.

When the polymerizable monomer having an ethylenically unsaturated group is polymerized to obtain the above-mentioned resin particles, examples of the polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkable monomers. body.

Examples of the non-crosslinkable monomers include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, maleic anhydride, etc. Monomer; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (methyl ) Lauryl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isocyanate (meth) acrylate and other alkyl (meth) acrylate compounds ; (Meth)acrylic acid 2-hydroxyethyl ester, (meth)acrylic acid glyceride, (meth)acrylic acid polyoxyethylene ester, (meth)acrylic acid glycidyl ester and other oxygen atom-containing (meth)acrylic acid ester compounds ; (Meth) acrylonitrile and other monomers containing nitrile; vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate and other vinyl acid ester compounds; ethylene, propylene, isoprene, butadiene Unsaturated hydrocarbons such as olefin; trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, chlorostyrene and other halogen-containing monomers.

Examples of the crosslinkable monomers include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and tetramethylolmethane di(meth)acrylate. , Trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylic acid Ester, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, 1,4-butane Polyfunctional (meth)acrylate compounds such as diol di(meth)acrylate; (iso) triallyl cyanurate, triallyl trimellitate, divinylbenzene, diene phthalate Silanes such as propyl ester, diallyl acrylamide, diallyl ether, γ-(meth) acryloxypropyl trimethoxysilane, trimethoxysilyl styrene, vinyl trimethoxysilane, etc. The monomer and so on.

The above-mentioned resin particles can be obtained by polymerizing the above-mentioned polymerizable monomer having an ethylenically unsaturated group by a known method. As this method, for example, a method of performing suspension polymerization in the presence of a radical polymerization initiator; and a method of using non-crosslinked seed particles to swell monomers together with a radical polymerization initiator to perform polymerization Wait.

When the substrate particles are inorganic particles or organic-inorganic mixed particles other than metal particles, examples of the inorganic substance used to form the substrate particles include silicon dioxide, aluminum oxide, barium titanate, zirconium oxide, and carbon. Black etc. The inorganic substance is preferably non-metallic. The particles formed of the above-mentioned silicon dioxide are not particularly limited, and examples include, for example, calcination of silicon compounds having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, if necessary, and calcination. And the particles obtained. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a cross-linked alkoxysilane polymer and an acrylic resin.

The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. The aforementioned core is preferably an organic core. The above-mentioned shell is preferably an inorganic shell. From the viewpoint of more effectively reducing the connection resistance between the electrodes, the base material particles are preferably organic-inorganic mixed particles having an organic core and an inorganic shell disposed on the surface of the organic core.

Examples of the material of the organic core include materials of the resin particles.

As the material of the above-mentioned inorganic shell, there may be mentioned the inorganic substances exemplified as the material of the above-mentioned substrate particles. The material of the inorganic shell is preferably silicon dioxide. The inorganic shell is preferably formed by baking a metal alkoxide into a shell on the surface of the core by a sol-gel method. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of silane alkoxide.

In the case where the substrate particles are metal particles, examples of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably non-metallic particles.

The average particle diameter of the substrate particles is preferably 0.005 μm or more, more preferably 0.01 μm or more, still more preferably 0.5 μm or more, still more preferably 1 μm or more, still more preferably 3 μm or more, and preferably 100 μm or less, more preferably 60 μm or less, further preferably 50 μm or less, and particularly preferably 40 μm or less. If the average particle diameter of the substrate particles is above the lower limit, the contact area between the conductive particles and the electrode becomes larger, so the conduction reliability between the electrodes is further increased, and the distance between the electrodes connected through the conductive particles can be more effectively reduced 'S connection resistance. Furthermore, when the conductive portion is formed on the surface of the base particle, aggregation is not likely to occur, and it is difficult to form aggregated conductive particles. If the average particle diameter of the substrate particles is equal to or less than the upper limit, the conductive particles are easily compressed sufficiently, and the connection resistance between the electrodes connected via the conductive particles can be more effectively reduced.

The average particle diameter of the substrate particles is particularly preferably 0.005 μm or more and 40 μm or less. If the average particle diameter of the substrate particles is within the range of 0.005 μm or more and 40 μm or less, the interval between the electrodes can be further reduced, and even if the thickness of the conductive portion is increased, smaller conductive particles can be obtained.

The particle diameter of the above-mentioned substrate particles represents the diameter when the substrate particles are truly spherical, and represents the maximum diameter when the substrate particles are not truly spherical.

The average particle diameter of the substrate particles is preferably a number average particle diameter. The average particle diameter of the base material particles is obtained by using a particle size distribution measuring device or the like. The average particle diameter of the substrate particles is preferably obtained by observing 50 arbitrary substrate particles using an electron microscope or an optical microscope, and calculating the average value. In the case of measuring the average particle diameter of the base particles among the conductive particles, for example, it can be measured as follows.

It was added to and dispersed in "TECHNOVIT 4000" manufactured by Kulzer Corporation so that the content of the conductive particles became 30% by weight, and an embedded resin for conductive particle inspection was produced. The ion milling device ("IM4000" manufactured by Hitachi High-Technologies Co., Ltd.) was used to disperse near the center of the conductive particles embedded in the resin for inspection to cut out the cross-section of the conductive particles. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 25,000 times, 50 conductive particles were randomly selected, and the substrate particles of each conductive particle were observed. The particle diameter of the substrate particles in each conductive particle is measured, and the arithmetic average of these is used as the particle diameter of the substrate particles.

(Conductive part) The method of forming the conductive portion on the surface of the base particle and the method of forming the solder portion on the surface of the base particle or the surface of the second conductive portion are not particularly limited. Examples of the method for forming the conductive portion and the solder portion include: a method using electroless plating, a method using electroplating, a method using physical collision, a method using mechanochemical reaction, a method using physical vapor deposition or physical adsorption Method and method of applying metal powder or paste containing metal powder and binder to the surface of substrate particles. The method of forming the conductive portion and the solder portion is preferably a method using electroless plating, electroplating, or physical collision. Examples of the method using physical vapor deposition include vacuum vapor deposition, ion plating, and ion sputtering. In addition, in the above-mentioned method using physical collision, for example, Thetacomposer (manufactured by Tokusho Corporation) can be used.

The melting point of the substrate particles is preferably higher than the melting points of the conductive portion and the solder portion. The melting point of the substrate particles is preferably more than 160°C, more preferably more than 300°C, further preferably more than 400°C, and particularly preferably more than 450°C. Furthermore, the melting point of the substrate particles may not reach 400°C. The melting point of the substrate particles may be 160°C or lower. The softening point of the substrate particles is preferably 260°C or higher. The softening point of the substrate particles may not reach 260°C.

The conductive particles may have a single-layer solder portion. The conductive particles may have a plurality of conductive parts (solder parts, second conductive parts). That is, two or more conductive parts may be stacked on the conductive particles. In the case where the conductive portion is two or more layers, the conductive particles preferably have solder on the outer surface portion of the conductive portion.

The above solder is preferably a metal (low melting point metal) having a melting point of 450°C or lower. The solder portion is preferably a metal layer (low melting point metal layer) having a melting point of 450° C. or lower. The low-melting-point metal layer is a layer containing a low-melting-point metal. The solder in the conductive particles and the solder particles are preferably metal particles having a melting point of 450° C. or lower (low-melting-point metal particles). The aforementioned low-melting-point metal particles are particles containing low-melting-point metal. The aforementioned low melting point metal means a metal having a melting point of 450°C or lower. The melting point of the above-mentioned low melting point metal is preferably 300°C or lower, more preferably 160°C or lower.

The melting point of the low melting point metal and the melting point of the solder particles can be determined by differential scanning calorimetry (DSC). Examples of differential scanning calorimetry (DSC) devices include "EXSTAR DSC7020" manufactured by SII.

In addition, the solder in the conductive particles preferably contains tin. In 100% by weight of the metal contained in the solder portion and in 100% by weight of the metal contained in the solder in the conductive particles, the tin content is preferably 30% by weight or more, more preferably 40% by weight or more, and It is preferably 70% by weight or more, and particularly preferably 90% by weight or more. If the content of tin contained in the solder in the solder portion and the conductive particles is at least the above lower limit, the reliability of conduction between the conductive particles and the electrode is further improved.

In addition, the content of the above-mentioned tin can use a high-frequency inductively coupled plasma luminescence spectroscopic analysis device ("ICP-AES" manufactured by Horiba, Ltd.) or a fluorescent X-ray analysis device ("EDX-800HS" manufactured by Shimadzu Corporation ) And so on.

By using conductive particles having the above-mentioned solder on the outer surface portion of the conductive portion, the solder melts and is joined to the electrodes, and the solder makes the electrodes conductive. For example, since the solder and the electrode are not in point contact but are easily in surface contact, the connection resistance is reduced. In addition, by using conductive particles having solder on the outer surface portion of the conductive portion, the bonding strength between the solder and the electrode is improved, and as a result, the peeling of the solder and the electrode is less likely to occur, thereby effectively improving the conduction reliability.

The low melting point metal constituting the solder portion and the solder is not particularly limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, and tin-indium alloy. In terms of excellent wettability to the electrode, the low melting point metal is preferably tin, tin-silver alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-indium alloy. More preferred are tin-bismuth alloys and tin-indium alloys.

The material constituting the solder (solder portion) is based on JIS Z3001: soldering term, and is preferably a filler having a liquidus of 450° C. or lower. Examples of the composition of the solder include metal compositions including zinc, gold, silver, lead, copper, tin, bismuth, and indium. A tin-indium system (117°C eutectic) with a low melting point and lead-free or a tin-bismuth system (139°C eutectic) is preferred. That is, the solder is preferably lead-free, preferably solder containing tin and indium, or solder containing tin and bismuth.

In order to further improve the bonding strength of the solder portion or the solder in the conductive particles and the electrode, the solder in the conductive particles may also include nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, Cobalt, bismuth, manganese, chromium, molybdenum, palladium and other metals. From the viewpoint of further improving the bonding strength of the solder portion or the solder in the conductive particles and the electrode, the solder in the conductive particles preferably contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further improving the bonding strength of the solder portion or the solder in the conductive particles and the electrode, the content of the metals used to increase the bonding strength is 100% by weight of the solder in the conductive particles, preferably 0.0001 % By weight or more, and preferably 1% by weight or less.

The melting point of the second conductive portion is preferably higher than the melting point of the solder portion. The melting point of the second conductive portion is preferably more than 160°C, more preferably more than 300°C, further preferably more than 400°C, even more preferably more than 450°C, particularly preferably more than 500°C, and most preferably more than 600°C . Since the above-mentioned solder portion has a low melting point, it melts during conductive connection. The second conductive portion preferably does not melt during conductive connection. The conductive particles are preferably used by melting solder, preferably by melting the solder portion, and preferably by melting the solder portion without melting the second conductive portion. By making the melting point of the second conductive portion higher than the melting point of the solder portion, it is possible to melt only the solder portion without melting the second conductive portion during conductive connection.

The absolute value of the difference between the melting point of the solder portion and the melting point of the second conductive portion exceeds 0°C, preferably 5°C or higher, more preferably 10°C or higher, even more preferably 30°C or higher, particularly preferably 50°C or higher , The best is above 100 ℃.

The second conductive portion preferably contains metal. The metal constituting the second conductive portion 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, cadmium, and alloys of these. In addition, as the above-mentioned metal, tin-doped indium oxide (ITO) may also be used. Only one kind of the above metals may be used, or two or more kinds may be used in combination.

The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer, a gold layer or a copper layer, and further preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably have a nickel layer, a gold layer or a copper layer, and further preferably have a copper layer. By using the conductive particles having these preferred conductive parts for the connection between the electrodes, the connection resistance between the electrodes is further reduced. Moreover, it is easier to form solder parts on the surfaces of the preferred conductive parts.

The thickness of the solder portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 10 μm or less, more preferably 1 μm or less, and further preferably 0.3 μm or less. If the thickness of the solder portion is not less than the above lower limit and not more than the upper limit, sufficient conductivity can be obtained, and the conductive particles do not become too hard, but the conductive particles are sufficiently deformed during connection between the electrodes.

The average particle diameter of the conductive particles is preferably 0.01 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, further preferably 3 μm or more, and preferably 100 μm or less, more preferably 60 μm or less, further preferably 50 μm or less, and particularly preferably 40 μm or less. If the average particle diameter of the conductive particles is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrodes, and it is easy to arrange a large amount of solder in the conductive particles between the electrodes, and the conduction is reliable Sex is further improved.

The average particle diameter of the conductive particles is more preferably a number average particle diameter. The average particle diameter of the conductive particles is obtained by observing any 50 conductive particles with an electron microscope or an optical microscope, calculating the average value, or performing laser diffraction particle size distribution measurement, for example.

The CV value of the particle diameter of the conductive particles is preferably 5% or more, more preferably 10% or more, and preferably 40% or less, more preferably 30% or less. If the CV value of the particle size is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode. However, the CV value of the particle diameter of the conductive particles may not reach 5%.

The CV value (variation coefficient) of the particle diameter of the conductive particles can be measured as follows.

CV value (%) = (ρ/Dn) × 100 ρ: Standard deviation of the particle size of conductive particles Dn: average particle diameter of conductive particles

The shape of the conductive particles is not particularly limited. The shape of the conductive particles may be spherical, may be other than spherical, or may be flat or the like.

In 100% by weight of the conductive material, the content of the conductive particles is preferably 1% by weight or more, more preferably 2% by weight or more, and further preferably 10% by weight or more, particularly preferably 20% by weight or more, and most preferably 30 More than 80% by weight, preferably 80% by weight or less, more preferably 60% by weight or less, and still more preferably 50% by weight or less. If the content of the conductive particles is more than the lower limit and less than the upper limit, the conductive particles can be more efficiently arranged on the electrodes, it is easy to arrange a large number of conductive particles between the electrodes, and the conduction reliability is further improved. From the viewpoint of further improving the conduction reliability, it is preferable that the content of the conductive particles is large.

(Thermosetting component) The conductive material of the present invention contains thermosetting components. The thermosetting component preferably contains a thermosetting compound. The conductive material may contain a thermosetting compound and a thermosetting agent as thermosetting components. In order to harden the conductive material more preferably, the conductive material preferably contains a thermosetting compound and a thermosetting agent as thermosetting components. In order to harden the conductive material more preferably, the conductive material preferably contains a hardening accelerator as a thermosetting component.

(Thermosetting component: thermosetting compound) The conductive material of the present invention preferably contains a thermosetting compound. The aforementioned thermosetting compound is a compound that can be hardened by heating. The thermosetting compound is not particularly limited. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth)acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, and polyaminomethines Acid ester compounds, polysiloxane compounds and polyimide compounds, etc. From the viewpoint of making the hardening property and viscosity of the conductive material better and further improving the conduction reliability, an epoxy compound or an episulfide compound is preferable, and an epoxy compound is more preferable. The conductive material preferably contains an epoxy compound. Only one type of the above thermosetting compound may be used, or two or more types may be used in combination.

The epoxy compound is a compound having at least one epoxy group. Examples of the epoxy compound include bisphenol A epoxy compounds, bisphenol F epoxy compounds, bisphenol S epoxy compounds, phenol novolac epoxy compounds, biphenyl epoxy compounds, and Phenolic novolac epoxy compound, biphenol epoxy compound, naphthalene epoxy compound, fusel epoxy compound, phenol aralkyl epoxy compound, naphthol aralkyl epoxy compound, dicyclopentane Ene type epoxy compound, anthracene type epoxy compound, epoxy compound with adamantane skeleton, epoxy compound with tricyclodecane skeleton, naphthyl ether type epoxy compound, and ring with three cores on the skeleton Oxygen compounds, etc. Only one kind of the epoxy compound may be used, or two or more kinds may be used in combination.

The epoxy compound is liquid or solid at normal temperature (23°C). When the epoxy compound is solid at normal temperature, the melting temperature of the epoxy compound is preferably equal to or lower than the melting point of the solder. By using the above-mentioned preferred epoxy compound, the viscosity is high at the stage of bonding the connection target member, and when acceleration is applied due to impact such as transportation, the positional deviation of the first connection target member and the second connection target member can be suppressed . Furthermore, the viscosity of the conductive material can be greatly reduced by the heat during hardening, and the solder in the conductive particles can be efficiently aggregated.

From the viewpoint of more effectively improving the insulation reliability and the viewpoint of more effectively improving the conduction reliability, the thermosetting component preferably contains an epoxy compound, and the thermosetting compound preferably contains an epoxy compound.

From the viewpoint of more effectively disposing the solder in the conductive particles on the electrode, the thermosetting compound preferably includes a thermosetting compound having a polyether skeleton.

Examples of the thermosetting compound having a polyether skeleton include a compound having a glycidyl ether group at both ends of an alkyl chain having 3 to 12 carbon atoms, and a polyether skeleton having 2 to 4 carbon atoms. Polyether type epoxy compound with 2 to 10 structural units in which the polyether skeleton is continuously bonded.

From the viewpoint of more effectively improving the heat resistance of the cured product, the above-mentioned thermosetting compound preferably contains a thermosetting compound having an isocyanuric acid skeleton.

Examples of the thermosetting compound having an isocyanuric acid skeleton include triisocyanurate-type epoxy compounds, and the TEPIC series (TEPIC-G, TEPIC-S, TEPIC- SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, TEPIC-UC) etc.

From the viewpoint of more efficiently arranging the solder in the conductive particles on the electrode, from the viewpoint of more effectively improving the conduction reliability between the electrodes to be connected above and below, and from the viewpoint of more effectively suppressing the discoloration of the thermosetting compound In particular, the thermosetting compound preferably has high heat resistance, and more preferably a novolac epoxy compound. Novolac epoxy compounds have relatively high heat resistance.

In 100% by weight of the conductive material, the content of the thermosetting compound is preferably 5% by weight or more, more preferably 8% by weight or more, and further preferably 10% by weight or more, and preferably 99% by weight or less, It is more preferably 90% by weight or less, further preferably 80% by weight or less, and particularly preferably 70% by weight or less. If the content of the thermosetting compound is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode, effectively improving the insulation reliability between the electrodes, and the electrode can be more effectively improved Intermittent reliability. From the viewpoint of more effectively improving the impact resistance, it is preferable that the content of the above thermosetting compound is large.

In the above-mentioned conductive material 100% by weight, the content of the above-mentioned epoxy compound is preferably 5% by weight or more, more preferably 8% by weight or more, and further preferably 10% by weight or more, and preferably 99% by weight or less, more It is preferably 90% by weight or less, more preferably 80% by weight or less, and particularly preferably 70% by weight or less. If the content of the epoxy compound is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode, the insulation reliability between the electrodes can be more effectively improved, and the electrode can be more effectively improved Intermittent reliability. From the viewpoint of further improving impact resistance, it is preferable that the content of the epoxy compound is large.

(Thermosetting component: thermosetting agent) The conductive material preferably contains a thermosetting agent. The conductive material preferably contains both the thermosetting compound and the thermosetting agent. The thermosetting agent thermally hardens the thermosetting compound. The above-mentioned thermosetting agent is not particularly limited. As the above-mentioned thermal hardener, there are imidazole hardener, phenol hardener, thiol hardener, amine hardener, acid anhydride hardener, thermal cation hardener, thermal radical generator, and the like. Only one type of the above-mentioned thermosetting agent may be used, or two or more types may be used in combination.

From the viewpoint that the conductive material can be hardened more quickly at a low temperature, the thermal hardener is preferably an imidazole hardener, a thiol hardener, or an amine hardener. In addition, from the viewpoint of improving the storage stability when the thermosetting compound and the thermosetting agent are mixed, the thermosetting agent is preferably a latent curing agent. The latent hardener is preferably a latent imidazole hardener, a latent thiol hardener or a latent amine hardener. In addition, the thermosetting agent may be coated with a polymer material such as polyurethane resin or polyester resin.

The imidazole hardener is not particularly limited. Examples of the above-mentioned imidazole hardener include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenyl Imidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-tris and 2,4-diamino-6 -[2'-methylimidazolyl-(1')]-ethyl-s-triisocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-benzene 4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-p-tolylmethyl-4-methyl-5-hydroxymethylimidazole , 2-m-tolylmethyl-4-methyl-5-hydroxymethylimidazole, 2-m-tolylmethyl-4,5-dihydroxymethylimidazole, 2-p-tolylmethyl-4,5 -Imidazole compounds in which hydrogen at the 5-position of 1H-imidazole is substituted by hydroxymethyl and hydrogen at the 2-position is substituted by phenyl or toluoyl in dihydroxymethylimidazole and the like.

The thiol hardener is not particularly limited. Examples of the thiol hardener include trimethylolpropane tri-3-mercaptopropionate, pentaerythritol tetra-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate.

The amine hardener is not particularly limited. Examples of the amine hardener include hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis(3-aminopropyl)-2,4,8, 10-tetraspiro[5.5]undecane, bis(4-aminocyclohexyl)methane, m-phenylenediamine, and diaminodiphenylbenzene, etc.

The acid anhydride hardener is not particularly limited, and as long as it is an acid anhydride used as a hardener for thermosetting compounds such as epoxy compounds, it can be widely used. Examples of the acid anhydride hardener include phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic acid. Anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, anhydride of phthalic acid derivatives, maleic anhydride, phthalic anhydride, methacrylic anhydride, Difunctional anhydride hardeners such as glutaric anhydride, succinic anhydride, glycerol bistrimellitic anhydride monoacetate, and ethylene glycol bistrimellitic anhydride, trifunctional anhydride hardeners such as trimellitic anhydride, and homobenzene Tetracarboxylic dianhydride, benzophenone tetracarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride, polyazelaic anhydride and other tetrafunctional acid anhydride hardeners, etc.

The above thermal cationic initiator is not particularly limited. Examples of the above-mentioned thermal cationic initiator include a cation hardener of an oxonium type, a cationic hardener of an oxonium type, a cationic hardener of a cerium system, and the like. Examples of the above-mentioned antimony-based cationic hardener include bis(4-third-butylphenyl) antimony hexafluorophosphate. Examples of the oxonium-based cationic hardener include trimethyloxonium tetrafluoroborate and the like. Examples of the cerium-based cationic hardener include tri-p-tolyl hexafluorophosphate and the like.

The thermal radical generator is not particularly limited. Examples of the thermal radical generator include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxides include di-tertiary butyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature of the thermosetting agent is preferably 50°C or higher, more preferably 70°C or higher, further preferably 80°C or higher, and preferably 250°C or lower, more preferably 200°C or lower, and further preferably Below 150°C, particularly preferably below 140°C. If the reaction starting temperature of the thermosetting agent is above the lower limit and below the upper limit, the solder in the conductive particles is more efficiently arranged on the electrode. From the viewpoint of more efficiently arranging the solder in the conductive particles on the electrode, and the viewpoint of more effectively improving the conduction reliability between the electrodes to be connected above and below, the reaction initiation temperature of the above-mentioned thermosetting agent is particularly Preferably, it is above 80°C and below 140°C.

From the viewpoint of more efficiently disposing the solder in the conductive particles on the electrode, the reaction initiation temperature of the above-mentioned thermosetting agent is preferably higher than the melting point of the above-mentioned solder particles, more preferably higher than 5°C, and further It is preferably higher than 10°C.

The reaction starting temperature of the above-mentioned thermosetting agent means the rising starting temperature of the exothermic peak in DSC.

The content of the aforementioned thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, and preferably 200 parts by weight or less, and more preferably 100 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. Furthermore, it is preferably 75 parts by weight or less. If the content of the thermosetting agent is more than the above lower limit, it is easy to sufficiently harden the conductive material. If the content of the thermosetting agent is equal to or less than the above upper limit, the remaining thermosetting agent that does not participate in hardening is unlikely to remain after curing, and the heat resistance of the cured product is further improved.

(Thermosetting component: hardening accelerator) The above conductive material may contain a hardening accelerator. The hardening accelerator is not particularly limited. The hardening accelerator preferably functions as a hardening catalyst in the reaction between the thermosetting compound and the thermosetting agent. The hardening accelerator preferably functions as a hardening catalyst in the reaction with the thermosetting compound. Only one kind of the curing accelerator may be used, or two or more kinds may be used in combination.

Examples of the hardening accelerator include phosphonium salts, tertiary amines, tertiary amine salts, quaternary onium salts, tertiary phosphines, crown ether complexes, amine complex compounds, and phosphonium alkylene. Specifically, examples of the hardening accelerator include imidazole compounds and isocyanurates of imidazole compounds; dicyandiamide, derivatives of dicyandiamide, melamine compounds, derivatives of melamine compounds, and diamine cis Butylene dinitrile, diethylidene triamine, triethylidene tetraamine, tetraethylidene pentaamine, bis(hexamethylene) triamine, triethanolamine, diaminodiphenylmethane, organic acid di Amine compounds such as hydrazine; 1,8-diazabicyclo[5,4,0]undecene-7, 3,9-bis(3-aminopropyl)-2,4,8,10- Tetraoxyspiro[5,5]undecane; boron trifluoride, boron trifluoride-amine complex compound; and triphenylphosphine, tricyclohexylphosphine, tributylphosphine and methyldiphenyl Phosphorus and other organic phosphorus compounds.

The phosphonium salt is not particularly limited. Examples of the above-mentioned phosphonium salts include tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium OO diethyldithiophosphate, methyl tributylphosphonium dimethyl phosphate, and tetra-n-butylphosphonium benzotris Azole, tetra-n-butylphosphonium tetrafluoroborate, tetra-n-butylphosphonium tetraphenylborate, etc.

From the viewpoint of arranging the solder in the conductive particles on the electrode more efficiently and improving the conduction reliability between the electrodes to be connected above and below, the hardening accelerator is preferably an imidazole compound, More preferably, it is a boron trifluoride-amine complex compound.

The content of the hardening accelerator is appropriately selected so as to harden the thermosetting compound well. The content of the hardening accelerator with respect to 100 parts by weight of the thermosetting compound is preferably 0.5 parts by weight or more, more preferably 0.8 parts by weight or more, and preferably 10 parts by weight or less, more preferably 8 parts by weight or less. If the content of the curing accelerator is more than the lower limit and less than the upper limit, the thermosetting compound can be cured satisfactorily. In addition, if the content of the hardening accelerator is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode, and the conduction between the upper and lower electrodes to be connected can be more effectively improved reliability.

(Flux) The conductive material of the present invention contains flux. By using flux, the cohesion of solder during conductive connection can be more effectively improved.

In the conductive material of the present invention, the flux includes a solid salt of the first compound having a carboxyl group and a second compound having an amine group, and a liquid as a reactant of the third compound having a carboxyl group and the fourth compound having an amine group Compound.

The solid salt of the first compound having a carboxyl group and the second compound having an amine group is solid at 25°C. The liquid compound described above as a reactant of the third compound having a carboxyl group and the fourth compound having an amine group is liquid at 25°C.

The solid salt of the first compound having a carboxyl group and the second compound having an amine group is preferably a solid in a conductive material at 25°C. The liquid compound as the reactant of the third compound having a carboxyl group and the fourth compound having an amine group is preferably a liquid in a conductive material at 25°C.

The first compound and the third compound preferably have the effect of cleaning the surface of the metal. The second compound preferably has an effect of neutralizing the first compound. The fourth compound preferably has an effect of neutralizing the third compound. The second compound and the fourth compound preferably have an effect of neutralizing the first compound or the third compound.

The solid salt is preferably a solid, and is preferably a neutralization reactant between the first compound and the second compound. The solid salt is preferably a salt produced by neutralization. As the conditions of the above neutralization reaction, the conditions of a heating temperature of 25°C to 60°C and a heating time of 5 minutes to 30 minutes are preferred.

The liquid compound is preferably a liquid, and is preferably a reactant of the third compound and the fourth compound. The above liquid compound is different from the above solid salt. The liquid compound is preferably a compound produced by a reaction (dehydration reaction), and preferably has an amide bond. The conditions of the above reaction (dehydration reaction) are preferably conditions of a heating temperature of 100°C to 200°C and a heating time of 5 minutes to 5 hours.

The weight ratio of the content of the solid salt to the content of the liquid compound (content of solid salt/content of liquid compound) is preferably 2 or more, more preferably 4 or more, and preferably 20 or less, more preferably 10 or less . If the weight ratio (solid salt content/liquid compound content) is above the lower limit and below the upper limit, the storage stability of the conductive material can be more effectively improved, and the conductive material can be further filled with flux, and It can more effectively improve the cohesion of solder during conductive connection.

The first compound and the third compound are preferably organic compounds having a carboxyl group. Examples of the first compound and the third compound include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid as aliphatic carboxylic acids. Acid, citric acid, malic acid; cyclohexyl carboxylic acid, 1,4-cyclohexyl dicarboxylic acid as cyclic aliphatic carboxylic acid; as aromatic carboxylic acid between phthalic acid, terephthalic acid, trimellitic acid Formic acid, ethylenediaminetetraacetic acid, etc. The first compound and the third compound are preferably glutaric acid, azelaic acid, or malic acid. If the first compound and the third compound satisfy the above-mentioned preferred aspects, the storage stability of the conductive material can be more effectively improved, the conductive material can be further filled with flux, and the conductive connection can be more effectively improved. The cohesion of the solder.

The first compound and the third compound may be the same compound or different compounds. From the viewpoint of more effectively improving the storage stability of the conductive material, the viewpoint of further filling the flux with the conductive material, and the viewpoint of more effectively improving the cohesiveness of the solder during conductive connection, the first compound and the above The third compound is preferably the same compound.

The second compound and the fourth compound are preferably organic compounds having an amine group. Examples of the second compound and the fourth compound include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, 2 -Methylbenzylamine, 3-methylbenzylamine, 4-tert-butylbenzylamine, N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N -Third butyl benzylamine, N-isopropylbenzylamine, N,N-dimethylbenzylamine, imidazole compounds, and triazole compounds. The second compound and the fourth compound are preferably benzylamine, 2-methylbenzylamine, or 3-methylbenzylamine. If the second compound and the fourth compound satisfy the above-mentioned preferred aspects, the storage stability of the conductive material can be more effectively improved, the conductive material can be further filled with flux, and the conductive connection can be more effectively improved. The cohesion of the solder.

The second compound and the fourth compound may be the same compound or different compounds. From the viewpoint of more effectively improving the storage stability of the conductive material, the viewpoint of further filling the flux with the conductive material, and the viewpoint of more effectively improving the cohesiveness of the solder during conductive connection, the second compound and the above The fourth compound is preferably the same compound.

The above-mentioned flux can be dispersed in the conductive material or attached to the surface of the conductive particles. From the viewpoint of more effectively improving the effect of the flux, the flux is preferably attached to the surface of the conductive particles.

The average particle diameter of the solid salt is preferably 0.01 μm or more, more preferably 0.05 μm or more, and preferably 10 μm or less, more preferably 1 μm or less. If the average particle size of the solid salt is above the lower limit and below the upper limit, the storage stability of the conductive material can be more effectively improved.

The ratio of the average particle diameter of the solid salt to the average particle diameter of the conductive particles (average particle diameter of the solid salt/average particle diameter of the conductive particles) is preferably 0.1 or more, more preferably 0.2 or more, and It is preferably 1 or less, and more preferably 0.5 or less. If the above ratio (average particle diameter of solid salt/average particle diameter of conductive particles) is above the lower limit and below the upper limit, the solid salt can be more effectively contacted with the conductive particles, and the flux performance during heating can be further improved .

The average particle diameter of the solid salt means the number average particle diameter. The average particle diameter of the solid salt can be obtained by observing 50 arbitrary solid salts with an electron microscope and calculating the average particle diameter of each solid salt.

The particle diameter of the above solid salt represents the diameter when the solid salt is truly spherical, and represents the maximum diameter when the solid salt is not truly spherical.

The content of the flux is preferably 1 part by weight or more, more preferably 10 parts by weight or more, and preferably 50 parts by weight or less, and more preferably 40 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. If the content of the flux is above the lower limit and below the upper limit, the storage stability of the conductive material can be more effectively improved, and the cohesiveness of the solder during conductive connection can be more effectively improved. Since the conductive material of the present invention satisfies the above-mentioned preferred aspect, it can be filled with more than 50 parts by weight of flux.

The content of the above flux in 100% by weight of the conductive material is preferably 0.05% by weight or more, more preferably 5% by weight or more, and preferably 20% by weight or less, more preferably 10% by weight or less. If the content of the flux is above the lower limit and below the upper limit, the storage stability of the conductive material can be more effectively improved, and the cohesiveness of the solder during conductive connection can be more effectively improved. In addition, if the content of the flux is above the lower limit and below the upper limit, it is less likely that an oxide film is formed on the surface of the solder and the electrode in the conductive particles, and furthermore, the oxide film formed on the conductive particles can be removed more effectively Oxide coating on the surface of solder and electrodes. Since the conductive material of the present invention satisfies the above-mentioned preferred aspect, it can be filled with more than 20% by weight of flux.

(filler) The above-mentioned conductive material may contain a filler. The filler may be an organic filler or an inorganic filler. By adding fillers, conductive particles can be uniformly aggregated on all electrodes of the substrate.

The conductive material preferably does not contain the filler or contains 5% by weight or less of the filler. In the case of using the above thermosetting compound, the smaller the content of the filler, the easier the conductive particles move on the electrode.

In 100% by weight of the conductive material, the content of the filler is preferably 0% by weight (not included) or more, and preferably 5% by weight or less, more preferably 2% by weight or less, and further preferably 1% by weight or less. If the content of the filler is above the lower limit and below the upper limit, the conductive particles are more efficiently arranged on the electrode.

(Other ingredients) The above conductive materials may also include, for example, fillers, extenders, softeners, plasticizers, tackifiers, thixotropic agents, leveling agents, polymerization catalysts, hardening catalysts, colorants, antioxidants, thermal stabilizers Agents, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, flame retardants and other additives.

(Connection structure) The connection structure of the present invention includes: a first connection object member having a first electrode on the surface; a second connection object member having a second electrode on the surface; and a connection portion that connects the first connection object member to the above The second connection object member is connected. In the connection structure of the present invention, the material of the connection portion is the conductive material. In the connection structure of the present invention, the connection portion is a hardened product of the conductive material. In the connection structure of the present invention, the first electrode and the second electrode are electrically connected by the conductive particles.

In the connection structure of the present invention, since a specific conductive material is used, the solder in the conductive particles tends to gather between the first electrode and the second electrode, so that the solder can be efficiently arranged on the electrode (wire). In addition, part of the solder is not easily arranged in the area (gap) where the electrode is not formed, so that the amount of solder arranged in the area where the electrode is not formed can be significantly reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, the electrical connection between the adjacent electrodes in the lateral direction that should not be connected can be prevented, and the insulation reliability can be improved.

In addition, in order to efficiently dispose the solder in the conductive particles on the electrode and significantly reduce the amount of solder disposed in the area where the electrode is not formed, it is preferable to use a conductive paste rather than a conductive film for the conductive material.

The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, and preferably 100 μm or less, more preferably 80 μm or less. The solder wetting area on the surface of the electrode (the area where the solder contacts in 100% of the exposed area of the electrode) is preferably 50% or more, more preferably 60% or more, further preferably 70% or more, and preferably Below 100%.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

1 is a cross-sectional view schematically showing a connection structure obtained by using a conductive material according to an embodiment of the present invention.

The connection structure 1 shown in FIG. 1 includes a first connection object member 2, a second connection object member 3, and a connection portion 4 that connects the first connection object member 2 and the second connection object member 3. The connection portion 4 is formed of the above-mentioned conductive material. In this embodiment, the conductive material contains conductive particles, thermosetting components, and flux. The conductive particles are solder particles. As the thermosetting component, a thermosetting compound and a thermosetting agent are included. In this embodiment, a conductive paste is used as a conductive material.

The connecting portion 4 has a solder portion 4A in which a plurality of solder particles are aggregated and joined to each other, and a hardened portion 4B obtained by thermosetting a thermosetting component.

The first connection object member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection object member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection object member 2 and the second connection object member 3 are electrically connected by the solder portion 4A. In addition, in the connection portion 4, there is no solder in a region (part of the hardened portion 4B) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a. In a region different from the solder part 4A (the hardened part 4B part), there is no solder separated from the solder part 4A. Furthermore, if it is a small amount, the solder may exist in a region (part of the hardened material portion 4B) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a.

As shown in FIG. 1, in the connection structure 1, a plurality of solder particles gather between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles melt, the melt of the solder particles wets on the surface of the electrode After diffusion and curing, the solder portion 4A is formed. Therefore, the connection area between the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 3a becomes larger. That is, by using solder particles, the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode are compared with the case of using conductive particles whose outer surface portion of the conductive portion is a metal such as nickel, gold, or copper The contact area of 3a becomes larger. Therefore, the conduction reliability and connection reliability in the connection structure 1 are improved. Furthermore, the flux contained in the conductive material is generally gradually deactivated by heating.

In addition, in the connection structure 1 shown in FIG. 1, the solder portions 4A are all disposed in the opposing regions between the first and second electrodes 2 a and 3 a. The connection structure 1X of the modification shown in FIG. 3 differs from the connection structure 1 shown in FIG. 1 only in the connection portion 4X. The connection portion 4X includes a solder portion 4XA and a cured object portion 4XB. Like the connection structure 1X, most of the solder portion 4XA is located in the area facing the first and second electrodes 2a and 3a, and a part of the solder portion 4XA is opposed to the first and second electrodes 2a and 3a. The area overflowed sideways. The solder portion 4XA that overflows laterally from the opposing area of the first and second electrodes 2a, 3a is a part of the solder portion 4XA, not the solder separated from the solder portion 4XA. Furthermore, in this embodiment, the amount of solder separated from the solder portion can be reduced, but there may be solder separated from the solder portion in the hardened portion.

If the amount of solder particles used is reduced, the connection structure 1 can be easily obtained. If the amount of solder particles used is increased, the connection structure 1X can be easily obtained.

In the connection structure 1, 1X, it is preferable to observe the portion of the first electrode 2a, the connection portions 4, 4X, and the second electrode 3a in the stacking direction opposite to the first electrode 2a and the second electrode 3a. The solder portions 4A and 4XA of the connecting portions 4 and 4X are arranged at 50% or more of the area of the opposing portion of the first electrode 2a and the second electrode 3a at 100% or more. By making the solder parts 4A and 4XA in the connection parts 4 and 4X satisfy the above-mentioned preferred aspect, the conduction reliability can be further improved.

Preferably, when the portion of the first electrode, the connection portion, and the second electrode facing each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode The solder part of the above-mentioned connection part is arranged at 50% or more of the area of the opposite part to 100%. More preferably, when the portion of the first electrode, the connection portion, and the second electrode facing each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, between the first electrode and the second electrode The solder part in the above-mentioned connection part is arranged at 60% or more of the area of the opposite part to 100%. Further preferably, when the portion of the first electrode, the connection portion, and the second electrode that are opposed to each other is viewed in the stacking direction of the first electrode, the first electrode, and the second electrode The solder part in the above-mentioned connection part is arranged in 70% or more of the area of the opposite part of 100%. It is particularly preferred that when the portion of the first electrode, the connection portion, and the second electrode facing each other in the stacking direction of the first electrode, the second electrode, and the second electrode is viewed, The solder part in the above-mentioned connection part is arranged at 80% or more of the area of the opposite part to 100%. Preferably, when the portion of the first electrode, the connection portion, and the second electrode facing each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode The solder part in the above-mentioned connection part is arranged at 90% or more of the area of the opposite part to 100%. By making the solder part in the connection part satisfy the above-mentioned preferred aspect, the conduction reliability can be further improved.

Preferably, when the opposite portion of the first electrode and the second electrode is viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and More than 60% of the solder part in the connection part is arranged at the opposite part of the second electrode. More preferably, when the opposite portion of the first electrode and the second electrode is observed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and More than 70% of the solder part in the connection part is arranged at the opposite part of the second electrode. Further preferably, when the portion of the first electrode and the second electrode facing each other is viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode More than 90% of the solder portion of the connection portion is arranged at the portion facing the second electrode. It is particularly preferred that when the opposite portion of the first electrode and the second electrode is observed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and More than 95% of the solder part of the connection part is arranged at the opposite part of the second electrode. Preferably, when the opposite portion of the first electrode and the second electrode is observed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and At least 99% of the solder portion of the connection portion is arranged at the opposite portion of the second electrode. By making the solder part in the connection part satisfy the above-mentioned preferred aspect, the conduction reliability can be further improved.

Next, an example of a method of manufacturing the connection structure 1 using the conductive material according to an embodiment of the present invention will be described in FIG. 2.

First, the first connection object member 2 having the first electrode 2a on the surface (upper surface) is prepared. Next, as shown in FIG. 2(a), a conductive material 11 including a thermosetting component 11B and a plurality of solder particles 11A is arranged on the surface of the first connection object member 2 (first step). The conductive material 11 contains a thermosetting compound, a thermosetting agent, and a flux as the thermosetting component 11B.

The conductive material 11 is disposed on the surface of the first connection object member 2 where the first electrode 2a is provided. After the conductive material 11 is arranged, the solder particles 11A are arranged on both the first electrode 2a (line) and the region (gap) where the first electrode 2a is not formed. Furthermore, the conductive material may be disposed only on the surface of the first electrode.

The method of disposing the conductive material 11 is not particularly limited, and examples include coating using a dispenser, screen printing, and ejection using an inkjet device.

Furthermore, the second connection object member 3 having the second electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2(b), of the conductive material 11 on the surface of the first connection object member 2, the second connection is arranged on the surface of the conductive material 11 opposite to the side of the first connection object member 2 Object member 3 (2nd step). The second connection object member 3 is arranged on the surface of the conductive material 11 from the side of the second electrode 3a. At this time, the first electrode 2a is opposed to the second electrode 3a.

Next, the conductive material 11 is heated above the melting point of the solder particles 11A (third step). It is preferable to heat the conductive material 11 to the curing temperature of the thermosetting component 11B (thermosetting compound) or higher. When this heating is performed, the solder particles 11A existing in the area where the electrode is not formed are collected between the first electrode 2a and the second electrode 3a (self-aggregation effect). In the case of using a conductive paste instead of a conductive film, the solder particles 11A are more effectively gathered between the first electrode 2a and the second electrode 3a. Also, the solder particles 11A are melted and joined to each other. In addition, the thermosetting component 11B is thermoset. As a result, as shown in FIG. 2( c ), the connection portion 4 connecting the first connection object member 2 and the second connection object member 3 is formed of the conductive material 11. The connection portion 4 is formed by the conductive material 11, the solder portion 4A is formed by joining a plurality of solder particles 11A, and the hardened portion 4B is formed by thermosetting the thermosetting component 11B. If the solder particles 11A are to be moved sufficiently, the movement of the solder particles 11A that is not located between the first electrode 2a and the second electrode 3a may start from the movement of the solder particles 11A between the first electrode 2a and the second electrode 3a Until the movement is completed, the temperature is not kept constant.

In this embodiment, it is preferable not to apply pressure in the second step and the third step. In this case, the weight of the second connection object member 3 is applied to the conductive material 11. Therefore, when the connection portion 4 is formed, the solder particles 11A are more efficiently collected between the first electrode 2a and the second electrode 3a. In addition, if pressurization is performed in at least one of the second step and the third step, the tendency of the solder particles 11A to hinder the action of gathering between the first electrode 2a and the second electrode 3a becomes high.

When overlapping the second connection object member with the first connection object member coated with the conductive material, the first connection may be performed in a state where the alignment of the electrode of the first connection object member and the electrode of the second connection object member is shifted When the target component overlaps with the second connection target component. In this embodiment, since no pressure is applied, the offset can be corrected to connect the electrode of the first connection object member and the electrode of the second connection object member (self-alignment effect). The reason is that the molten solder that self-agglomerates between the electrode of the first connection object member and the electrode of the second connection object member is electrically conductive between the electrode of the first connection object member and the electrode of the second connection object member. When the contact area of other components of the material becomes the smallest, the energy is more stable. In addition, the reason is that the force to make the connection structure that is the smallest area, that is, the alignment connection structure works. At this time, it is desirable that the conductive material does not harden, and at this temperature and time, the viscosity of the components other than the conductive particles of the conductive material is sufficiently low.

The viscosity of the conductive material at the melting point of the solder is preferably 50 Pa·s or less, more preferably 10 Pa·s or less, and further preferably 1 Pa·s or less, and preferably 0.1 Pa·s or more, more preferably 0.2 Pa·s or more. If the viscosity is equal to or lower than the upper limit, the solder in the conductive particles can be efficiently aggregated. If the viscosity is above the lower limit, the gap of the connection portion can be suppressed, and the overflow of the conductive material to the parts other than the connection portion can be suppressed.

The viscosity of the conductive material at the melting point of the solder is determined by the following method.

The viscosity of the conductive material at the melting point of the above solder can use STRESSTECH (manufactured by REOLOGICA), etc., under strain control 1 rad, frequency 1 Hz, heating rate 20°C/min, measurement temperature range 25°C to 200°C (however, in solder When the melting point exceeds 200°C, the upper limit of the temperature is determined as the melting point of the solder). Based on the measurement results, the viscosity at the melting point (°C) of the solder is evaluated.

In this way, the connection structure 1 shown in FIG. 1 is obtained. Furthermore, the second step and the third step can be performed continuously. Moreover, after performing the above-mentioned second step, the obtained laminate of the first connection object member 2, the conductive material 11, and the second connection object member 3 may be moved to the heating section to perform the above-mentioned third step. In order to perform the heating, the laminate may be arranged on the heating member, or the laminate may be arranged in the heated space.

The heating temperature in the third step is preferably 140°C or higher, more preferably 160°C or higher, and preferably 450°C or lower, more preferably 250°C or lower, and further preferably 200°C or lower. If the heating temperature in the third step is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode, and the electrode between the upper and lower electrodes to be connected can be more effectively increased Continuity reliability.

Examples of the heating method in the third step include a method using a reflow furnace or an oven to heat the entire connection structure to the melting point of the solder in the conductive particles or higher and the curing temperature of the thermosetting component or higher, or only A method of locally heating the connecting portion of the connecting structure.

Examples of the apparatus used for the local heating method include a hot plate, a hot air gun that applies hot air, a soldering iron, and an infrared heater.

In addition, when the heating plate is used for local heating, it is preferable to form a metal with high thermal conductivity directly under the connecting portion, and other parts that are not suitable for heating are formed with a material with low thermal conductivity such as fluororesin.

The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include semiconductor chips, semiconductor packages, LED (Light Emitting Diode) chips, LED packages, capacitors, and diodes. And electronic components such as resin film, printed circuit board, flexible printed circuit board, flexible flat cable, rigid printed circuit board, glass epoxy substrate, glass substrate and other circuit boards. The first and second connection target members are preferably electronic parts.

At least one of the first connection object member and the second connection object member is preferably a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. At least one of the first connection object member and the second connection object member is preferably a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. Resin films, flexible printed circuit boards, flexible flat cables, and rigid flexible substrates have the characteristics of high flexibility and relatively light weight. When a conductive film is used for the connection of the connection object member, there is a tendency that the solder in the conductive particles is difficult to gather on the electrode. In contrast, by using conductive paste, even if a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, the solder in the conductive particles can be efficiently collected on the electrode, Thereby, the conduction reliability between the electrodes can be sufficiently improved. When a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, it can be obtained more efficiently than when using other connection target members such as semiconductor wafers. The effect of improving the conduction reliability between the generated electrodes.

Examples of the electrodes provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS (Steel Use Stainless) electrodes, and tungsten electrodes. When the connection object member is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode or a copper electrode. When the member to be connected is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. In addition, when the above electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode having an aluminum layer on the surface area of the metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

In the connection structure of the present invention, the first electrode and the second electrode are preferably arranged in a region array or a peripheral device. When the first electrode and the second electrode are arranged in the area array or the peripheral device, the solder in the conductive particles can be more effectively aggregated on the electrode. The above-mentioned area array refers to a structure in which electrodes are arranged in a lattice on the surface of the connection target member where the electrodes are arranged. The above-mentioned peripheral device refers to a structure in which electrodes are arranged on the outer peripheral portion of the connection target member. In the case where the electrodes are arranged in a comb-like configuration, the solder can be condensed in a direction perpendicular to the comb. In contrast, in the above-mentioned area array or peripheral device structure, the solder must be placed on the entire surface on the surface where the electrodes are arranged Coagulates evenly. Therefore, in the previous method, the amount of solder tends to become non-uniform. In contrast, in the method of the present invention, the solder can be uniformly aggregated over the entire surface.

Hereinafter, Examples and Comparative Examples will be listed to specifically explain the present invention. The present invention is not limited to the following embodiments.

Thermosetting components (thermosetting compounds): Thermosetting compound 1: "D.E.N-431" manufactured by The Dow Chemical Company, epoxy resin Thermosetting compound 2: "jER152" manufactured by Mitsubishi Chemical Corporation, epoxy resin

Thermosetting component (thermosetting agent): Thermosetting agent 1: "BF3-MEA" manufactured by Tokyo Chemical Industry Co., Ltd., boron trifluoride-monoethylamine complex Thermosetting agent 2: "2PZ-CN", 1-cyanoethyl-2-phenylimidazole manufactured by Shikoku Chemical Industry Co., Ltd.

Conductive particles: Conductive particles 1: Solder particles, "SnAg3Cu0.5 (ST-2)" (average particle size 2.2 μm) manufactured by Mitsui Metals Mining Corporation Conductive particles 2: Solder particles, "SnAg3Cu0.5 (DS-10)" (average particle size 13 μm) manufactured by Mitsui Metals Mining Corporation

Flux: Flux 1: solid salt of glutaric acid and benzylamine, average particle size 1 μm How to make flux 1: 24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added to a glass bottle, and dissolved at room temperature until it became uniform. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. Put the obtained mixed solution into a refrigerator at 5°C to 10°C, and leave it overnight. The precipitated crystals were separated by filtration, washed with water, and vacuum dried. The dried crystal was heated at 140°C for 15 minutes to completely melt it, and gradually re-precipitated at 25°C for 30 minutes, thereby obtaining flux 1.

Flux 2: Liquid compound as a reactant of glutaric acid and benzylamine How to make flux 2: In a three-necked flask, 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) were added, and the reaction was heated at 120° C. for 3 hours to obtain flux 2.

Flux 3: solid salt of succinic acid and benzylamine, average particle size 10 μm How to make flux 3: Add 24 g of water as a reaction solvent and 11.809 g of succinic acid (manufactured by Wako Pure Chemical Industries, Ltd.) to a glass bottle, and dissolve at room temperature until it becomes uniform. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. Put the obtained mixed solution into a refrigerator at 5°C to 10°C, and leave it overnight. The precipitated crystals were separated by filtration, washed with water, and vacuum dried. The dried crystals were heated at 190°C for 10 minutes to be completely melted, and gradually re-precipitated at 25°C for 30 minutes, thereby obtaining flux 3.

Flux 4: Liquid compound as a reactant of succinic acid and benzylamine How to make flux 4: In a three-necked flask, 11.809 g of succinic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) were added, and the mixture was heated at 200° C. for 2 hours for reaction to obtain flux 4.

Flux 5: solid salt of malic acid and benzylamine, average particle size 5 μm How to make flux 5: In a glass bottle, add 24 g of water as a reaction solvent and 13.409 g of malic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and dissolve at room temperature until it becomes uniform. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. Put the obtained mixed solution into a refrigerator at 5°C to 10°C, and leave it overnight. The precipitated crystals were separated by filtration, washed with water, and vacuum dried. The dried crystal was heated at 180° C. for 15 minutes to completely melt it, and gradually re-precipitated at 25° C. for 30 minutes, thereby obtaining flux 5.

Flux 6: Liquid compound as a reactant of malic acid and benzylamine How to make flux 6: In a three-necked flask, 13.409 g of malic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) were added, and the reaction was heated at 150° C. for 3 hours to obtain flux 6.

(Average particle size of solid salt) The average particle size of the solid salt is measured using a scanning electron microscope ("S-4300SEN" manufactured by Hitachi, Ltd.), and the particle size of any 50 solid salts is measured and calculated from the average value.

(Examples 1 to 3 and Comparative Examples 1 to 4) (1) Production of conductive materials (anisotropic conductive paste) The components shown in Tables 1 and 2 below were blended in the amounts shown in Tables 1 and 2 below to obtain a conductive material (anisotropic conductive paste).

(2) Fabrication of the first connection structure (L/S=50 μm/50 μm) Using the just-made conductive material (anisotropic conductive paste), the first connection structure was produced as follows.

A glass epoxy substrate (FR-4 substrate) (first connection target member) with a copper electrode pattern (thickness of copper electrodes of 12 μm) having an electrode length of 3 mm on the upper surface and an L/S of 50 μm/50 μm was prepared. In addition, a flexible printed circuit board (second connection target member) having a copper electrode pattern with an electrode length of 3 mm (copper electrode thickness of 12 μm) on the lower surface with an L/S of 50 μm/50 μm was prepared.

The overlapping area of the glass epoxy substrate and the flexible printed substrate is 1.5 cm×3 mm, and the number of connected electrodes is 75 pairs.

On the upper surface of the above glass epoxy substrate, the conductive material (anisotropic conductive paste) just made is applied to the electrodes of the glass epoxy substrate by screen printing using a metal mask in a thickness of 100 μm, A layer of conductive material (anisotropic conductive paste) is formed. Next, the flexible printed circuit board is stacked on the upper surface of the conductive material (anisotropic conductive paste) layer so that the electrodes face each other. No pressure is applied at this time. The weight of the flexible printed circuit board is applied to the conductive material (anisotropic conductive paste) layer. In this state, heating is performed in such a way that the temperature of the conductive material (anisotropic conductive paste) layer reaches the melting point of the solder 5 seconds after the temperature rise starts. Furthermore, the conductive material (anisotropic conductive paste) layer was heated such that the temperature of the conductive material (anisotropic conductive paste) layer reached 220° C. or higher 15 seconds after the temperature was started, and the conductive material (anisotropic conductive paste) layer was hardened to obtain a connection structure. No pressure is applied during heating.

(3) Fabrication of the second connection structure (L/S=75 μm/75 μm) A glass epoxy substrate (FR-4 substrate) (first connection object member) with a copper electrode pattern (thickness of copper electrodes of 12 μm) having an electrode length of 3 mm on the upper surface and an L/S of 75 μm/75 μm was prepared. In addition, a flexible printed circuit board (second connection target member) having a copper electrode pattern with an electrode length of 3 mm (copper electrode thickness of 12 μm) on the lower surface with an L/S of 75 μm/75 μm was prepared.

Except for using the above-mentioned glass epoxy substrate and flexible printed circuit board with different L/S, a second connection structure was obtained in the same manner as the production of the first connection structure.

(4) Fabrication of the third connection structure (L/S=100 μm/100 μm) Prepare a glass epoxy substrate (FR-4 substrate) (first connection target member) with a copper electrode pattern (thickness of copper electrodes of 12 μm) with an electrode length of 3 mm on the upper surface and L/S of 100 μm/100 μm. In addition, a flexible printed circuit board (second connection target member) having a copper electrode pattern with an electrode length of 3 mm (copper electrode thickness of 12 μm) having an L/S of 100 μm/100 μm on the lower surface was prepared.

Except for using the above-mentioned glass epoxy substrate and flexible printed circuit board with different L/S, a third connection structure was obtained in the same manner as the production of the first connection structure.

(Evaluation) (1) Existing state of flux Confirm whether the flux in the obtained conductive material contains the solid salt of the first compound having a carboxyl group and the second compound having an amine group, and as the reactant of the third compound having a carboxyl group and the fourth compound having an amine group Liquid compound. Determine the presence of flux based on the following criteria.

[Judgment criteria for the presence of flux] ○: The flux in the conductive material contains the solid salt of the first compound having a carboxyl group and the second compound having an amine group, and the liquid compound as a reactant of the third compound having a carboxyl group and the fourth compound having an amine group Both ×: The flux in the conductive material does not contain the solid salt of the first compound having a carboxyl group and the second compound having an amine group, and the liquid compound as a reactant of the third compound having a carboxyl group and the fourth compound having an amine group At least one of

(2) Storage stability The viscosity (η1) of the just-made conductive material (anisotropic conductive paste) at 25°C was measured. Furthermore, the conductive material (anisotropic conductive paste) just produced was left at room temperature for 24 hours, and the viscosity (η2) of the conductive material (anisotropic conductive paste) after being placed at 25°C was measured. The above viscosity was measured using an E-type viscometer ("TVE22L" manufactured by Toki Industry Co., Ltd.) at 25°C and 5 rpm. The viscosity increase rate (η2/η1) was calculated from the measured value of viscosity. The storage stability was determined according to the following criteria.

[Judgment criteria for storage stability] ○: The viscosity increase rate (η2/η1) is 1.5 or less △: The viscosity increase rate (η2/η1) exceeds 1.5 and is 2.0 or less ×: The viscosity increase rate (η2/η1) exceeds 2.0

(3) The placement accuracy of the solder on the electrode (solder cohesion) In the obtained first, second, and third connection structures, when observing the opposing portion of the first electrode and the second electrode in the stacking direction of the first electrode, the connection portion, and the second electrode, evaluate the first The ratio X of the area where the solder part is arranged in the connection part of the connection part of 100% of the area of the opposing part of the 1st electrode and the 2nd electrode. Determine the placement accuracy of the solder on the electrode (solder cohesiveness) according to the following criteria.

[Judgment criteria for placement accuracy (solder cohesion) of solder on electrodes] ○○: Ratio X is 70% or more ○: Ratio X is 60% or more and less than 70% △: The ratio X is more than 50% and less than 60% ×: The ratio X does not reach 50%

(4) Conduction reliability between upper and lower electrodes In the obtained first, second, and third connection structures (n=15), the connection resistance of each connection portion between the upper and lower electrodes was measured by the four-terminal method, respectively. Calculate the average value of the connection resistance. In addition, the connection resistance can be obtained by measuring the voltage when a fixed current flows based on the relationship of voltage = current × resistance. The conduction reliability is determined according to the following criteria.

[Judgment criteria for conduction reliability] ○○: The average value of the connection resistance is 50 mΩ or less ○: The average value of the connection resistance exceeds 50 mΩ and is less than 70 mΩ △: The average value of the connection resistance exceeds 70 mΩ and is less than 100 mΩ ×: The average value of the connection resistance exceeds 100 mΩ, or a poor connection occurs

(5) Insulation reliability between adjacent electrodes in the lateral direction In the obtained first, second, and third connecting structures (n=15), after being left in an environment of 85°C and 85% humidity for 100 hours, apply 5 V between the electrodes adjacent in the lateral direction, The resistance value was measured at 25 locations. Determine the insulation reliability according to the following criteria.

[Judgment criteria for insulation reliability] ○ ○: The average value of the connection resistance is 10 ⁷ Ω or more ○: The average value of the connection resistance is 10 ⁶ Ω or more and less than 10 ⁷ Ω △: The average value of the connection resistance is 10 ⁵ Ω Above and less than 10 ⁶ Ω ×: The average value of the connection resistance is less than 10 ⁵ Ω

The results are shown in Tables 1 and 2 below.

[Table 1]

[Table 2]

The same tendency was observed when resin films, flexible flat cables, and rigid flexible substrates were used instead of flexible printed substrates.

1: Connect the structure 1X: connection structure 2: The first connection target component 2a: 1st electrode 3: The second connection target component 3a: 2nd electrode 4: connection part 4A: Solder Department 4B: Hardened part 4X: connection 4XA: Soldering Department 4XB: Hardened part 11: conductive material 11A: Solder particles (conductive particles) 11B: Thermosetting component 21: Conductive particles (solder particles) 31: Conductive particles 32: substrate particles 33: conductive part (conductive part with solder) 33A: Second conductive part 33B: Soldering Department 41: Conductive particles 42: Soldering Department

1 is a cross-sectional view schematically showing a connection structure obtained by using a conductive material according to an embodiment of the present invention. 2(a) to (c) are cross-sectional views illustrating steps of an example of a method for manufacturing a connection structure using a conductive material according to an embodiment of the present invention. 3 is a cross-sectional view showing a modification of the connection structure. 4 is a cross-sectional view showing a first example of conductive particles that can be used for a conductive material. 5 is a cross-sectional view showing a second example of conductive particles that can be used for a conductive material. 6 is a cross-sectional view showing a third example of conductive particles that can be used for a conductive material.

1: Connect the structure

2: The first connection target component

2a: 1st electrode

3: The second connection target component

3a: 2nd electrode

4: connection part

4A: Solder Department

4B: Hardened part

Claims (10)

A conductive material comprising a plurality of conductive particles having solder on the outer surface portion of the conductive portion, thermosetting components, and flux, and The flux includes a solid salt of a first compound having a carboxyl group and a second compound having an amine group, and a liquid compound that is a reactant of a third compound having a carboxyl group and a fourth compound having an amine group. The conductive material according to claim 1, wherein the weight ratio of the content of the solid salt to the content of the liquid compound is 2 or more and 20 or less. The conductive material according to claim 1 or 2, wherein the first compound and the third compound are the same compound. The conductive material according to claim 1 or 2, wherein the second compound and the fourth compound are the same compound. The conductive material according to claim 1 or 2, wherein the average particle diameter of the solid salt is 0.01 μm or more and 10 μm or less. The conductive material according to claim 1 or 2, wherein the above thermosetting component contains a thermosetting compound, and The content of the flux is 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. The conductive material according to claim 1 or 2, wherein the content of the above-mentioned flux is 100% by weight or more and 20% by weight or less in 100% by weight of the conductive material. The conductive material according to claim 1 or 2, wherein the average particle diameter of the conductive particles is 0.01 μm or more and 50 μm or less. If the conductive material of claim 1 or 2, it is a conductive paste. A connection structure including: a first connection object member having a first electrode on a surface; A second connection object member having a second electrode on the surface; and A connection portion that connects the first connection object member and the second connection object member; The material of the above-mentioned connecting portion is a conductive material according to any one of claims 1 to 9, and The first electrode and the second electrode are electrically connected by the conductive particles.

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