TWI789395B - Conductive material and connection structure - Google Patents

Abstract

The present invention provides a conductive material, which can effectively improve the storage stability of the conductive material, effectively improve the agglomeration of the solder during conductive connection, and further effectively improve the heat resistance of the cured product. The conductive material of the present invention includes a plurality of conductive particles having solder on the outer surface of the conductive part, a thermosetting compound, and flux, and has the first constitution "there is no such thing as having twice or more than the average particle diameter of the above-mentioned flux" flux with a particle size equal to or greater than 100% of the total number of fluxes mentioned above, or fluxes with a particle size twice or greater than the average particle size of the above-mentioned fluxes are present in less than 10% of the total number of the above-mentioned fluxes", and The second configuration is any one or more of "the composition obtained by removing the conductive particles from the conductive material is a colloid, and the flux is present in the form of colloidal particles".

Description

Conductive material and connection structure

The present invention relates to a conductive material comprising conductive particles having solder on the outer surface of a conductive part. Also, the present invention relates to a connection structure using the above-mentioned conductive material.

Anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film are well known. In the aforementioned anisotropic conductive material, the conductive particles are dispersed in the binder.

The aforementioned anisotropic conductive materials are used to obtain various connection structures. As the connection through the above-mentioned anisotropic conductive material, for example, the connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass, coated glass)), the connection between a semiconductor chip and a flexible printed substrate (COF (Chip on Film) , film-on-chip)), the connection between the semiconductor chip and the glass substrate (COG (Chip on Glass, glass-on-glass)), and the connection between the flexible printed substrate and the glass epoxy substrate (FOB (Film on Board, coated board)), etc. .

When using the above-mentioned anisotropic conductive material, for example, when the electrodes of the flexible printed circuit board and the electrodes of the glass epoxy substrate are electrically connected, the anisotropic conductive material including conductive particles is disposed on the glass epoxy substrate. Next, the flexible printed circuit board is laminated, heated and pressurized. Thereby, the anisotropic conductive material is hardened, and between electrodes are electrically connected via electroconductive particle, and the connection structure is obtained.

As an example of the aforementioned anisotropic conductive material, Patent Document 1 below discloses an anisotropic conductive material including conductive particles and a resin component that is not completely cured at the melting point of the conductive particles. As said electroconductive particle, specifically, tin (Sn), indium (In), bismuth (Bi), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), gallium ( Metals such as Ga), silver (Ag) and thallium (Tl), or alloys of these metals.

Patent Document 1 describes a resin heating step of heating an anisotropic conductive material to a temperature higher than the melting point of the above-mentioned conductive particles without completing the hardening of the above-mentioned resin component, and a resin component hardening step of hardening the above-mentioned resin component, Electrically connect the electrodes. In addition, Patent Document 1 describes mounting with the temperature distribution shown in FIG. 8 of Patent Document 1. In Patent Document 1, the conductive particles are melted in the resin component that has not been cured at the temperature at which the anisotropic conductive material is heated.

In addition, Patent Document 2 below discloses a solder paste (conductive material) containing a solder flux and an alloy powder mainly composed of tin. The above-mentioned flux is a flux obtained by adding an active agent to a solvent and dispersing it. The above-mentioned solvent is a polyhydric alcohol having 2 to 4 hydroxyl groups. The above-mentioned active agent is a sugar with 4-6 hydroxyl groups. The average particle size of the active agent is 100 μm or less.

In addition, Patent Document 3 below discloses a solder composition (conductive material) containing a lead-free SnZn-based alloy and a flux for soldering. The above flux for soldering contains an epoxy resin and an organic carboxylic acid. The above-mentioned organic carboxylic acid is dispersed in the above-mentioned solder composition as a solid at room temperature (25° C.). [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-260131 [Patent Document 2] Japanese Patent Laid-Open No. 2007-216296 [Patent Document 3] WO2003/002290A1

[Problem to be solved by the invention]

In the previous conductive materials as described in Patent Documents 1 to 3, the moving speed of conductive particles or solder particles on the electrodes (wires) is relatively slow, and it is difficult to efficiently agglomerate the solder to the upper and lower electrodes that should be connected situation in between. As a result, the conduction reliability and insulation reliability between electrodes tend to be lowered.

As a method of efficiently aggregating the solder on the electrodes, a method of increasing the amount of flux prepared in the conductive material, etc. are mentioned.

However, if the content of the flux in the conductive material is increased, the flux may react with the thermosetting compound in the conductive material, and the storage stability of the conductive material may decrease. Moreover, when the content of the flux in a conductive material is increased, the heat resistance of the hardened|cured material of a conductive material may fall.

In the conventional conductive materials described in Patent Documents 1 to 3, it is difficult to satisfy all the requirements of improving the storage stability of the conductive material, improving the agglomeration of the solder at the time of conductive connection, and improving the heat resistance of the cured product.

The object of the present invention is to provide a conductive material, which can effectively improve the storage stability of the conductive material, effectively improve the agglomeration of the solder during conductive connection, and further effectively improve the heat resistance of the cured product. Moreover, the object of this invention is to provide the connection structure using the said electrically-conductive material. [Technical means to solve the problem]

According to a broad aspect of the present invention, there is provided a conductive material comprising a plurality of conductive particles having solder on the outer surface of the conductive part, a thermosetting compound, and flux, and having the following first constitution and second configuration. Any one or more of the constituents.

1st composition: There is no flux having a particle diameter twice or more than the average particle diameter of the above-mentioned flux, or in 100% of the total number of the above-mentioned fluxes, the average particle diameter of the above-mentioned flux is twice or more Flux with a particle size of less than 10% exists.

2nd structure: The composition which removed the said electroconductive particle from the said electrically-conductive material is a colloid, and the said flux exists in the form of a colloidal particle.

In a specific aspect of the conductive material of the present invention, there is no flux having a particle size greater than 1.5 times the average particle size of the above-mentioned flux, or in 100% of the total number of the above-mentioned fluxes, there is Less than 20% of fluxes having particle diameters greater than 1.5 times the average particle diameter of the above-mentioned fluxes exist.

In a specific aspect of the conductive material of the present invention, the average particle diameter of the above-mentioned flux is 1 μm or less.

In a specific aspect of the conductive material of the present invention, the content of the flux is 1 part by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the thermosetting compound.

In a specific aspect of the conductive material of the present invention, in 100% by weight of the conductive material, the content of the above 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 above-mentioned conductive material is a conductive paste.

According to a broad aspect of the present invention, there is provided a connection structure comprising: a first connection target member having a first electrode on its surface; a second connection target member having a second electrode on its surface; and a connection target member. part, which connects the first member to be connected with the second member to be connected; and the material of the connection part is the above-mentioned conductive material, and the first electrode and the second electrode are electrically connected by the solder part in the connection part. sexual connection.

In a specific aspect of the connection structure of the present invention, the portion where the first electrode and the second electrode face each other is viewed from the lamination direction of the first electrode, the connection portion, and the second electrode In this case, the solder portion in the connection portion is disposed on at least 50% of 100% of the area of the portion where the first electrode and the second electrode face each other. [Effect of Invention]

The conductive material of the present invention includes a plurality of conductive particles having solder on the outer surface of the conductive portion, a thermosetting compound, and flux, and has any one or more of the first configuration and the second configuration. Since the conductive material of the present invention has the above structure, it can effectively improve the storage stability of the conductive material, effectively improve the agglomeration of the solder during conductive connection, and further effectively improve the heat resistance of the cured product.

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

(Conductive material) The conductive material of this invention contains the some electroconductive particle which has solder on the outer surface part of a conductive part, a thermosetting compound, and flux. The electrically conductive material of this invention has any one or more of the following 1st structure and 2nd structure. The conductive material of the present invention may have only the following first structure, may have only the following second structure, or may have both the following first structure and the following second structure.

1st composition: There is no flux having a particle diameter twice or more than the average particle diameter of the above-mentioned flux, or in 100% of the total number of the above-mentioned fluxes, the average particle diameter of the above-mentioned flux is twice or more Flux with particle size less than 10% exists

Second configuration: The composition obtained by removing the conductive particles from the conductive material is a colloid, and the flux exists in the form of colloidal particles

The conductive material of the present invention may also have a configuration (1a configuration) in which flux having a particle diameter twice or more the average particle diameter of the above-mentioned flux does not exist as the first configuration. The conductive material of the present invention may also have a structure in which the number of fluxes having a particle size twice or more the average particle size of the above-mentioned flux exists in less than 10% of the total number of the above-mentioned fluxes (100%) ( Form 1b).

The conductive material of the present invention may have only the above-mentioned 1a structure, may only have the above-mentioned 1b structure, may only have the above-mentioned second structure, may have the above-mentioned 1a structure and the above-mentioned second structure, or may have the above-mentioned 1b structure and the above-mentioned structure. 2nd composition.

Since the present invention has the above structure, it can improve the storage stability of the conductive material, effectively improve the agglomeration of the solder at the time of conductive connection, and further effectively improve the heat resistance of the cured product.

Since the present invention has the above-mentioned structure, when the electrodes are electrically connected, a plurality of conductive particles can be efficiently arranged on the electrodes (wires), and the solder can be efficiently agglomerated on the upper and lower parts to be connected. between electrodes. Moreover, some of the plurality of conductive particles are not easily arranged in the region (gap) where no electrodes are formed, and the amount of conductive particles arranged in the region where electrodes are not formed can be considerably reduced. Therefore, the conduction reliability between electrodes can be improved. Furthermore, electrical connection between laterally adjacent electrodes that should not be connected can be prevented, and insulation reliability can be improved.

Soldering flux is mainly formulated in conductive materials for the purpose of removing oxides existing on the surface of solder and electrodes in conductive particles, or preventing the formation of such oxides. In the present invention, the flux is relatively difficult to agglomerate, and the particle size of the flux is relatively small. Furthermore, in the present invention, the flux is dispersed relatively well. Therefore, in the present invention, even if the content of the flux in the conductive material is relatively small, the oxides present on the surface of the solder in the conductive particles and the surface of the electrodes can be removed and the formation of the oxides can be prevented. In the present invention, even if the content of flux in the conductive material is relatively small, the agglomeration of the solder during the conductive connection can be effectively improved. In the present invention, the flux content in the conductive material can be relatively small.

In the comparison of the flux having the same content, in the case of the presence of the flux in the present invention, compared with the case of not in the presence of the flux in the present invention, the conductive connection can be effectively improved. The agglomeration of the solder at this time.

In the present invention, the content of the flux in the conductive material may not be set to a large amount, but may be relatively small, so that 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 addition, the melting point (activation temperature) of the flux in the conductive material is lower than the Tg of the thermosetting compound in the conductive material in most cases. The more flux content in the conductive material, the heat resistance of the cured product of the conductive material Tendency to decrease sexuality. In the present invention, the content of the flux in the conductive material can be relatively small instead of large, so that the heat resistance of the cured product of the conductive material can be effectively improved.

Since the present invention has the above structure, it can meet all the requirements of improving the storage stability of the conductive material, improving the agglomeration of the solder at the time of conductive connection, and improving the heat resistance of the cured product.

Furthermore, in the present invention, positional displacement between electrodes can be prevented. In the case of conductive connection, the second connection object member is superimposed on the first connection object member on which the conductive material is arranged on the upper surface. At this time, even when the first connection object member and the second connection object member are overlapped in a state where the electrodes of the first connection object member and the electrodes of the second connection object member are misaligned, in the present invention , and the offset can also be corrected. As a result, the electrodes of the first connection object member and the electrodes of the second connection object member can be connected (self-alignment effect).

From the viewpoint of further improving the agglomeration of the solder, the above-mentioned conductive material is preferably liquid at 25° C., and is preferably a conductive paste.

From the viewpoint of further improving the agglomeration of the solder, the viscosity (η25) of the conductive material at 25°C is preferably at least 20 Pa·s, more preferably at least 30 Pa·s, and more preferably 500 Pa·s Below, more preferably below 300 Pa·s. The above-mentioned viscosity (η25) can be adjusted appropriately according to the type and amount of compounded ingredients.

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

The above-mentioned conductive material can be used in the form of a conductive paste, a conductive film, and the like. The above-mentioned conductive paste is preferably an anisotropic conductive paste, and the above-mentioned conductive film is preferably an anisotropic conductive film. From the viewpoint of further improving the agglomeration of solder, it is preferable that the above-mentioned conductive material is a conductive paste. The above-mentioned conductive material is preferably used for the electrical connection of the electrodes. The above-mentioned conductive material is preferably a circuit connection material.

Hereinafter, each component contained in a conductive material is demonstrated. Furthermore, in this specification, "(meth)acrylic acid" means either or both of "acrylic acid" and "methacrylic acid", and "(meth)acrylate" means "acrylate" and "methacrylic acid". Acrylate "one or both.

(Electroconductive particle) The said electroconductive particle electrically connects between electrodes of a connection object member. The said electroconductive particle system has solder in the outer surface part of a conductive part. The said electroconductive particle may be the solder particle which consists of solder. The above-mentioned solder particles have solder on the outer surface of the conductive part. Both the central 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 in which the central part and the conductive outer surface are all solder. The said electroconductive particle may have the electroconductive part arrange|positioned on the surface of the base material particle and this base material particle. In this case, the said electroconductive particle has solder in the outer surface part of a conductive part.

The said electroconductive particle system has solder in the outer surface part of a conductive part. The above-mentioned base particles may be solder particles formed of solder. The above-mentioned conductive particles may be solder particles in which both the substrate particle and the outer surface portion of the conductive part are solder.

Furthermore, compared with the case of using the above-mentioned solder particles, when using conductive particles having base particles not formed of solder and solder portions arranged on the surface of the base particles, the conductive particles are difficult to accumulate on the electrodes. Furthermore, since the weldability of electroconductive particle|grains is low, the electroconductive particle which moved to the electrode tends to move out of an electrode easily, and there exists a tendency for the suppression effect of the misalignment between electrodes to also become low. Therefore, it is preferable that the said electroconductive particle is a solder particle which consists of solder.

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

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

The electroconductive particle 21 shown in FIG. 4 is a solder particle. The whole electroconductive particle 21 is formed with solder. The electroconductive particle 21 does not have a base material particle in a core, and is not a core-shell particle. Both the central part of the electroconductive particle 21 and the outer surface part of a conductive part are formed with solder.

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

The electroconductive particle 31 shown in FIG. 5 is provided with the electroconductive part 33 arrange|positioned on the surface of the base material particle 32 and the base material particle 32. As shown in FIG. The conductive part 33 covers the surface of the substrate particle 32 . The electroconductive particle 31 is the coated particle which the surface of the base material particle 32 was coated with the electroconductive part 33.

The conductive portion 33 has a second conductive portion 33A and a solder portion 33B (first conductive portion). The electroconductive particle 31 is equipped with the 2nd electroconductive part 33A between the base material particle 32 and the solder part 33B. Therefore, the electroconductive particle 31 has the base material particle 32, the 2nd conductive part 33A arrange|positioned on the surface of the base material particle 32, and the solder part 33B arrange|positioned on the outer surface of the 2nd conductive part 33A.

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

The conductive part 33 of the conductive particle 31 in FIG. 5 has a 2-layer structure. The electroconductive particle 41 shown in FIG. 6 has the solder part 42 as a single-layer electroconductive part. The electroconductive particle 41 is equipped with the solder part 42 arrange|positioned on the surface of the base material particle 32 and the base material particle 32.

Hereinafter, other details of electroconductive particle are demonstrated.

(Substrate Particles) Examples of the above-mentioned substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, metal particles, and the like. The aforementioned substrate particles are preferably substrate particles other than metal particles, more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic hybrid particles. The aforementioned substrate particle may be a core-shell particle having a core and a shell arranged on the surface of the core. The aforementioned core may be an organic core, and the aforementioned shell may be an inorganic shell.

The above-mentioned substrate 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 effect of the present invention can be exhibited more effectively, and conductive particles more suitable for electrical connection between electrodes can be obtained.

When connecting between electrodes using the said electroconductive particle, after arranging the said electroconductive particle between electrodes, it press-bonds, and compresses the said electroconductive particle. When the substrate particles are resin particles or organic-inorganic hybrid particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrodes becomes large. Therefore, the conduction reliability between electrodes becomes higher.

Various resins are preferably used as the material of the above-mentioned resin particles. As the material of the above-mentioned resin particles, for example, polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; polymethyl methacrylate, Acrylic resins 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, Polyester, Polyphenylene Ether, Polyacetal, Polyimide, Polyamideimide, Polyether Etherketone, polyethersulfone, and polymers obtained by polymerizing one or more kinds of various polymerizable monomers having ethylenically unsaturated groups, etc.

It is possible to design and synthesize any resin particles with compressive properties suitable for conductive materials, and the hardness of the resin particles can be easily controlled to a preferred range. Therefore, the material of the above-mentioned resin particles is preferably made of one or more than two kinds of resin particles. A polymer formed by polymerizing polymerizable monomers with multiple ethylenically unsaturated groups.

When polymerizing a polymerizable monomer having an ethylenically unsaturated group to obtain the aforementioned resin particles, examples of the aforementioned polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkable monomers. singleness of sex.

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

Examples of the above-mentioned crosslinkable monomers include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and tetramethylolmethane di(meth)acrylate. ester, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate Acrylates, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, 1,4- Multifunctional (meth)acrylate compounds such as butanediol di(meth)acrylate; triallyl (iso)cyanurate, triallyl trimellitate, divinylbenzene, diphthalate Allyl ester, diallyl acrylamide, diallyl ether, γ-(meth)acryloxypropyl trimethoxysilane, trimethoxysilyl styrene, vinyl trimethoxysilane, etc. Silane monomer, etc.

The said resin particle can be obtained by polymerizing the said polymerizable monomer which has an ethylenically unsaturated group by a well-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 polymerizing by using non-crosslinked seed particles to swell monomers together with a radical polymerization initiator, etc. .

When the above-mentioned substrate particles are inorganic particles or organic-inorganic hybrid particles other than metal particles, examples of inorganic substances used as materials for the above-mentioned substrate particles include silica, alumina, barium titanate, zirconia, and carbon black etc. The above-mentioned inorganic substances are preferably not metals. The particles made of the above-mentioned silica are not particularly limited, and examples thereof include cross-linked polymer particles formed by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, and then optionally Particles obtained by calcining. Examples of the above-mentioned organic-inorganic hybrid particles include organic-inorganic hybrid particles made of a crosslinked alkoxysilyl polymer and an acrylic resin.

The aforementioned 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 aforementioned shell is preferably an inorganic shell. From the viewpoint of more effectively reducing connection resistance between electrodes, the substrate particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell arranged on the surface of the organic core.

As a material of the said organic core, the material of the said resin particle etc. are mentioned.

Examples of the material of the above-mentioned inorganic shell include the inorganic substances listed as the material of the above-mentioned substrate particle. The material of the above-mentioned inorganic shell is preferably silicon dioxide. The inorganic shell is preferably formed by forming a shell of a metal alkoxide on the surface of the core by a sol-gel method, and then firing the shell. The aforementioned metal alkoxide is preferably a silane alkoxide. The above-mentioned inorganic shell is preferably formed of silane alkoxide.

When the said base material particle is a metal particle, silver, copper, nickel, silicon, gold, titanium etc. are mentioned as a metal used as the material of this metal particle. However, it is preferable that the above-mentioned substrate particles are not metal particles.

The particle size of the substrate particles is preferably at least 0.5 μm, more preferably at least 1 μm, further preferably at least 3 μm, and more preferably at most 100 μm, more preferably at most 60 μm, further preferably at least 50 μm the following. If the particle size of the above-mentioned substrate particles is more than the above-mentioned lower limit, the contact area between the conductive particles and the electrodes becomes larger, so the conduction reliability between the electrodes becomes higher, and the gap between the electrodes connected via the conductive particles can be reduced more effectively. The connection resistance. Furthermore, when forming an electroconductive part on the surface of a base material particle, it becomes difficult to aggregate, and it becomes difficult to form aggregated electroconductive particle. Electroconductive particle can be fully compressed easily that the particle diameter of the said base material particle is below the said upper limit, and the connection resistance between the electrodes connected via electroconductive particle can be reduced more effectively.

The particle diameter of the above-mentioned substrate particles is preferably not less than 5 μm and not more than 40 μm. If the particle diameter of the above-mentioned substrate particles is within the range of 5 μm to 40 μm, the gap between electrodes can be further reduced, and even if the thickness of the conductive portion is thickened, smaller conductive particles can be obtained.

Regarding the particle diameter of the above-mentioned base material particle, when the base material particle is a true spherical shape, it means the diameter, and when the base material particle is not a true spherical shape, it means the maximum diameter.

The particle diameter of the above-mentioned substrate particles represents a number average particle diameter. The particle diameter of the above-mentioned substrate particles is determined using a particle size distribution measuring device or the like. The particle diameter of the substrate particles is preferably obtained by observing 50 arbitrary substrate particles with an electron microscope or an optical microscope and calculating an average value. In electroconductive particle, when measuring the particle diameter of the said base material particle, it can measure as follows, for example.

It was added to "Technovit 4000" manufactured by Kulzer Corporation so that the content of the conductive particles became 30% by weight, and dispersed to prepare an embedding resin for conductive particle inspection. The cross section of the conductive particle was cut using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Co., Ltd.) so as to pass through the vicinity of the center of the conductive particle in the embedding resin for inspection. Then, using an electric 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 particle of each conductive particle was observed. The particle diameter of the substrate particle in each electroconductive particle was measured, and these were arithmetically averaged, and it was set as the particle diameter of a substrate particle.

(Conductive portion) The method of forming the conductive portion on the surface of the substrate particle and the method of forming the solder portion on the surface of the substrate particle or the surface of the second conductive portion are not particularly limited. As a method of forming the above-mentioned conductive part and the above-mentioned solder part, for example, a method by electroless plating; a method by electroplating; a method by physical collision; a method by mechanochemical reaction; methods of plating or physical adsorption; and methods of coating metal powder, or a paste containing metal powder and a binder, on the surface of substrate particles, etc. The method of forming the conductive portion and the solder portion is preferably electroless plating, electroplating or physical collision. Examples of the method utilizing physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering. In addition, in the above-mentioned method by physical collision, for example, Theta Composer (manufactured by Tokusu Works Co., Ltd.) or the like is used.

It is preferable that the melting point of the said base material particle|grains is higher than the melting point of the said conductive part and the said solder part. The melting point of the above-mentioned substrate particles is preferably over 160°C, more preferably over 300°C, further preferably over 400°C, especially preferably over 450°C. In addition, the melting point of the said base material particle does not need to be 400 degreeC or less. The melting point of the above-mentioned substrate particles may be 160° C. or lower. The softening point of the above-mentioned substrate particles is preferably 260° C. or higher. The softening point of the above-mentioned substrate particles may not be 260°C.

The said electroconductive particle may have the solder part of a single layer. The said electroconductive particle may have the electroconductive part (solder part, 2nd electroconductive part) of several layers. That is, in the said electroconductive particle, the electroconductive part may be laminated|stacked two or more layers. When the said electroconductive part is two or more layers, it is preferable that the said electroconductive particle has solder in the outer surface part of an electroconductive part.

The aforementioned solder is preferably a metal having a melting point of 450° C. or lower (low melting point metal). The aforementioned solder portion is preferably a metal layer (low melting point metal layer) having a melting point of 450° C. or lower. The above-mentioned low-melting-point metal layer is a layer containing a low-melting-point metal. It is preferable that the solder in the said electroconductive particle is the metal particle (low melting point metal particle) whose melting point is 450 degreeC or less. The above-mentioned low-melting-point metal particles are particles containing a 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. Moreover, it is preferable that the solder in the said electroconductive particle contains tin. The content of tin is preferably at least 30% by weight, more preferably at least 40% by weight, 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. , and more preferably 70% by weight or more, especially preferably 90% by weight or more. The conduction|electrical_connection reliability of electroconductive particle and an electrode will become higher as content of tin contained in the solder in the said solder part and the said electroconductive particle is more than the said minimum.

Furthermore, the content of the above-mentioned tin can be determined using a high-frequency inductively coupled plasma emission spectrometer ("ICP-AES" manufactured by Horiba Corporation) or a fluorescent X-ray analyzer ("EDX-800HS" manufactured by Shimadzu Corporation) Wait for the measurement.

By using the electroconductive particle which has the said solder on the outer surface part of a conductive part, a solder melt|dissolves and joins with an electrode, and a solder makes conduction between electrodes. For example, since the solder and the electrodes are likely to be in surface contact rather than point contact, the connection resistance becomes low. In addition, by using conductive particles having solder on the outer surface of the conductive part, the bonding strength between the solder and the electrode becomes higher, and as a result, peeling between the solder and the electrode is less likely to occur, and the conduction reliability is effectively improved.

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

It is preferable that the material which comprises the said solder (solder part) is a filler material whose liquidus line is 450 degreeC or less based on JIS Z3001: Soldering term. As a composition of the said solder, the metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium, etc. is mentioned, for example. It is preferably low melting point and lead-free tin-indium system (117°C eutectic) or tin-bismuth system (139°C eutectic). That is, it is preferable that the above-mentioned solder does not contain lead, and it is preferably a solder containing tin and indium, or a solder containing tin and bismuth.

In order to further improve the bonding strength between the solder in the solder portion or the conductive particles and the electrode, the solder in the conductive particles may also contain nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, Cobalt, bismuth, manganese, chromium, molybdenum, palladium and other metals. Moreover, it is preferable that the solder in the said electroconductive particle contains nickel, copper, antimony, aluminum, or zinc from a viewpoint of further improving the joint strength of the solder in a solder part or electroconductive particle, and an electrode. From the point of view of further improving the bonding strength between the solder and the electrode in the solder portion or the conductive particles, the content of the metals for improving the bonding strength is preferably 0.0001 in 100% by weight of the solder in the conductive particles. % by weight or more, and preferably not more than 1% by weight.

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 over 160°C, more preferably over 300°C, more preferably over 400°C, still more preferably over 450°C, especially preferably over 500°C, most preferably over 600°C . Since the above-mentioned solder portion has a low melting point, it melts during conductive connection. It is preferable that the said 2nd electroconductive part does not fuse|melt at the time of electroconductive connection. It is preferable to use the said electroconductive particle for melting solder, It is preferable to use for melting the said solder part, It is preferable to use it for melting the said solder part, and it does not melt the said 2nd electroconductive part. Since the melting point of the second conductive portion is higher than that of the solder portion, only the solder portion can be melted 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, still more preferably 30°C or higher, and most preferably 50°C or higher , preferably above 100°C.

It is preferable that the said 2nd electroconductive part 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, and cadmium, and alloys thereof. Moreover, tin-doped indium oxide (ITO) can also be used as said metal. The said metal may use only 1 type, and may use 2 or more types together.

The above-mentioned second conductive part 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 still more preferably a copper layer. It is preferable that an electroconductive particle has a nickel layer, a palladium layer, a copper layer, or a gold layer, It is more preferable to have a nickel layer, a gold layer, or a copper layer, It is still more preferable to have a copper layer. The connection resistance between electrodes becomes lower by using the electroconductive particle which has these preferable electroconductive parts for connection between electrodes. Also, the solder portion can be formed more easily on the surface of these preferred conductive portions.

The thickness of the solder portion is preferably at least 0.005 μm, more preferably at least 0.01 μm, more preferably at most 10 μm, more preferably at most 1 μm, and still more preferably at most 0.3 μm. Sufficient electroconductivity is acquired as the thickness of a solder part is more than the said minimum and below the said upper limit, and electroconductive particle does not become hard too much, and electroconductive particle fully deforms at the time of connection between electrodes.

The particle size of the above-mentioned conductive particles is preferably at least 0.5 μm, more preferably at least 1 μm, further preferably at least 3 μm, and more preferably at most 100 μm, more preferably at most 60 μm, further preferably at least 50 μm or less, preferably less than 40 μm. If the particle size of the above-mentioned conductive particles is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder in the conductive particles can be more efficiently arranged on the electrodes, and it is easy to arrange more solder in the conductive particles between the electrodes, and conduction can be achieved. Reliability becomes higher.

The particle size of the above-mentioned conductive particles is preferably an average particle size, more preferably a number average particle size. The average particle diameter of electroconductive particle can be calculated|required by observing 50 arbitrary electroconductive particles with an electron microscope or an optical microscope, calculating an average value, or performing a laser diffraction particle size distribution measurement, for example.

The CV value of the particle diameter of the above-mentioned conductive particles is preferably at least 5%, more preferably at least 10%, and is preferably at most 40%, more preferably at most 30%. Solder can be arrange|positioned more efficiently on an electrode as the CV value of the said particle diameter is more than the said minimum and below the said upper limit. However, the CV value of the particle diameter of the said electroconductive particle may be less than 5%.

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

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

The shape of the said electroconductive particle is not specifically limited. The shape of the said electroconductive particle may be spherical, and may be other than spherical shape, such as a flat shape.

In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned conductive particles is preferably at least 1% by weight, more preferably at least 2% by weight, further preferably at least 10% by weight, especially preferably at least 20% by weight, most preferably at least 20% by weight. It is 30% by weight or more, preferably 95% by weight or less, more preferably 90% by weight or less, further preferably 85% by weight or less. In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned conductive particles may be less than 80% by weight. If the content of the above-mentioned conductive particles is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder in the conductive particles can be more efficiently arranged on the electrodes, and it is easy to arrange more solder in the conductive particles between the electrodes, and the conduction is reliable. Sex becomes higher. From a viewpoint of further improving conduction reliability, it is preferable that there are many content of the said electroconductive particle.

(Thermosetting Compound) The conductive material of the present invention contains a thermosetting compound. The above-mentioned thermosetting compound is a compound that can be cured by heating. Examples of the thermosetting compounds include: oxetane compounds, epoxy compounds, episulfide compounds, (meth)acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, Ester compounds, polysiloxane compounds and polyimide compounds, etc. From the viewpoint of improving the curability and viscosity of the conductive material and further improving conduction reliability, epoxy compounds or episulfide compounds are preferred, and epoxy compounds are more preferred. The above-mentioned conductive material preferably includes an epoxy compound. The said thermosetting compound may use only 1 type, and may use 2 or more types together.

As the above-mentioned epoxy compound, aromatic epoxy compounds such as resorcinol-type epoxy compounds, naphthalene-type epoxy compounds, biphenyl-type epoxy compounds, benzophenone-type epoxy compounds, and phenolic novolac-type epoxy compounds are preferable. family of epoxy compounds. The melting temperature of the epoxy compound is preferably not higher than the melting point of solder. The melting temperature of the epoxy compound is preferably not higher than 100°C, more preferably not higher than 80°C, further preferably not higher than 40°C. By using the above-mentioned preferable epoxy compound, the position of the first connection object member and the second connection object member can be suppressed when the viscosity is high at the stage of laminating the connection object members, and when acceleration is given by the impact of transportation or the like offset. Furthermore, the viscosity can be significantly reduced by the heat at the time of hardening, and the aggregation of the solder in electroconductive particle can be performed efficiently.

In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned thermosetting compound is preferably at least 5% by weight, more preferably at least 8% by weight, further preferably at least 10% by weight, and preferably not more than 60% by weight, More preferably, it is 55 weight% or less, More preferably, it is 50 weight% or less, Most preferably, it is 40 weight% or less. If the content of the above-mentioned thermosetting compound is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder in the conductive particles can be more efficiently arranged on the electrodes, the positional displacement between the electrodes can be further suppressed, and the conduction between the electrodes can be further improved. reliability.

(Thermosetting agent) It is preferable that the said electrically-conductive material contains a thermosetting agent. The above-mentioned conductive material preferably contains a thermosetting agent together with the above-mentioned thermosetting compound. The thermosetting agent thermosets the thermosetting compound. Examples of the thermosetting agent include imidazole curing agents, phenol curing agents, mercaptan curing agents, amine curing agents, acid anhydride curing agents, thermal cationic curing agents, and thermal radical generators. The said thermosetting agent may use only 1 type, and may use 2 or more types together.

From the viewpoint that the conductive material can be cured more rapidly at low temperature, the above-mentioned thermosetting agent is preferably an imidazole curing agent, a mercaptan curing agent, or an amine curing agent. Furthermore, from the viewpoint of improving storage stability when mixing the thermosetting compound and the thermosetting agent, the thermosetting agent is preferably a latent curing agent. The latent hardener is preferably a latent imidazole hardener, a latent mercaptan hardener or a latent amine hardener. Furthermore, the above-mentioned thermosetting agent may be coated with a polymer material such as polyurethane resin or polyester resin.

The above-mentioned imidazole curing agent is not particularly limited. Examples of the imidazole curing agent 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-trimellitate and 2,4-diamino-6 -[2'-Methylimidazolyl-(1')]-Ethyl-s-tri-isocyanuric acid adduct, etc.

The above-mentioned mercaptan curing agent is not particularly limited. Examples of the mercaptan curing agent include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate.

The aforementioned amine hardener is not particularly limited. Examples of the amine hardener include: boron trifluoride-amine complexes, hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis(3-amino Propyl)-2,4,8,10-tetraspiro[5.5]undecane, bis(4-aminocyclohexyl)methane, m-phenylenediamine and diaminodiphenylene, etc.

The aforementioned thermal cationic curing agent is not particularly limited. Examples of the thermal cationic curing agent include iodonium-based cationic curing agents, oxonium-based cationic curing agents, and perium-based cationic curing agents. Bis(4-tert-butylphenyl)iodonium hexafluorophosphate etc. are mentioned as said iodonium type cationic hardening agent. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate and the like. Examples of the above-mentioned permeic cationic curing agent include tris-p-tolyl percite hexafluorophosphate and the like.

The aforementioned thermal radical generating agent is not particularly limited. As said thermal radical generating agent, an azo compound, an organic peroxide, etc. are mentioned. As said azo compound, azobisisobutyronitrile (AIBN) etc. are mentioned. Examples of the organic peroxide include di-tert-butyl peroxide, methyl ethyl ketone peroxide, and the like.

The reaction initiation temperature of the thermosetting agent is preferably at least 50°C, more preferably at least 60°C, still more preferably at least 70°C, and more preferably at most 250°C, more preferably at most 200°C, and still more preferably at 190°C. °C or lower, especially preferably 180 °C or lower. Solder is more efficiently arrange|positioned on an electrode as the reaction start temperature of the said thermosetting agent is more than the said minimum and below the said upper limit.

The content of the above-mentioned thermosetting agent is not particularly limited. With respect to 100 parts by weight of the above-mentioned thermosetting compound, the content of the above-mentioned thermosetting agent is preferably at least 0.01 parts by weight, more preferably at least 1 part by weight, and is preferably at most 200 parts by weight, more preferably at most 100 parts by weight, Furthermore, it is more preferably 75 parts by weight or less. When content of the said thermosetting agent is more than the said minimum, it becomes easy to fully harden a thermosetting compound. If the content of the above-mentioned thermosetting agent is below the above-mentioned upper limit, excess thermosetting agent that does not participate in hardening will not easily remain after curing, and the heat resistance of the cured product will become higher.

(Flux) The conductive material of the present invention contains flux. The conductive material of the present invention preferably has a structure in which there is no flux having a particle size twice or more the average particle size of the above-mentioned flux (1a structure). In the conductive material of the present invention, it is preferable that the number of fluxes having a particle diameter twice or more the average particle diameter of the above-mentioned flux is present in less than 10% of the total number of the above-mentioned fluxes (100%) Composition (Constitution 1b). The conductive material of the present invention preferably has a composition in which a composition obtained by removing the conductive particles from the conductive material is a colloid, and the flux exists in the form of colloidal particles (second configuration).

When the above-mentioned conductive material has the above-mentioned configuration 1a, it is preferable that there is no flux having a particle diameter of 1.8 times or more the average particle diameter of the above-mentioned flux, and it is more preferable that there is no flux having an average particle diameter of the above-mentioned flux. Flux with a particle size of 1.5 times or more. If the average particle diameter of the above-mentioned flux satisfies the above-mentioned preferred conditions, the storage stability can be further improved, the agglomeration of the solder can be further improved, and further, the heat resistance of the hardened product can be further improved.

When the above-mentioned conductive material has the above-mentioned configuration 1b, it is preferable that, in 100% of the total number of the above-mentioned fluxes, the flux having a particle diameter twice or more than the average particle diameter of the above-mentioned flux is preferably 8% or less The number exists. More preferably, the number of fluxes having a particle size twice or more the average particle size of the above-mentioned flux is present in an amount of 6% or less based on 100% of the total number of the above-mentioned fluxes. If the ratio of the number of fluxes having a particle size twice or more the average particle size of the above-mentioned flux is not more than the above-mentioned upper limit, the storage stability can be further improved, the agglomeration of the solder can be further improved, and further, the flux can be further improved. Heat resistance of hardened products.

It is preferable that there is no flux having a particle diameter of 1.5 times or more the average particle diameter of the above-mentioned flux, or that the average particle diameter of the above-mentioned flux is 1.5 times or more in 100% of the total number of the above-mentioned fluxes. The number of fluxes with particle size is less than 20%. It is preferable that the number of fluxes having a particle diameter not less than 1.5 times the average particle diameter of the above-mentioned flux exists in less than 20% of the total number of the above-mentioned fluxes (100%). More preferably, the number of fluxes having a particle size of 1.5 times or more the average particle size of the above-mentioned flux is present in an amount of 10% or less based on 100% of the total number of the above-mentioned fluxes. Furthermore, it is preferable that the number of fluxes having a particle diameter of 1.5 times or more the average particle diameter of the above-mentioned flux exists in a number of 5% or less in 100% of the total number of the above-mentioned fluxes. If the ratio of the number of fluxes having a particle size of 1.5 times or more the average particle size of the above-mentioned flux does not reach the above-mentioned upper limit and is not more than the above-mentioned upper limit, the storage stability can be further improved, and the agglomeration of the solder can be further improved. Furthermore, the heat resistance of a cured product can be further improved.

The average particle size of the above-mentioned flux is preferably 1 μm or less from the viewpoint of more effectively improving the storage stability, more effectively improving the agglomeration of the solder, and more effectively improving the heat resistance of the hardened product. , more preferably less than 1 μm, further preferably 0.8 μm or less. The lower limit of the average particle diameter of the above-mentioned flux is not particularly limited. The average particle diameter of the above-mentioned flux may be 0.1 μm or more.

The particle size of the above-mentioned flux indicates the diameter when the flux is spherical, and the maximum diameter when the flux is not spherical.

The average particle diameter of the above-mentioned flux represents the number average particle diameter. The particle diameter of the above-mentioned flux is preferably obtained by observing 50 arbitrary fluxes with an electron microscope and calculating an average value.

The CV value (coefficient of variation) of the particle size of the above-mentioned flux is from the viewpoint of more effectively improving the storage stability, the more effectively improving the agglomeration of the solder, and the more effectively improving the heat resistance of the hardened product. Preferably it is 40% or less, More preferably, it is 20% or less. The lower limit of the CV value of the particle size of the above-mentioned flux is not particularly limited. The CV value of the particle size of the above-mentioned flux can be 0.01% or more.

The CV value (coefficient of variation) of the particle size of the above flux can be measured as follows.

CV value (%)=(ρ/Dn)×100 ρ: Standard deviation of particle size of flux Dn: Average value of particle size of flux

The shape of the above flux is not particularly limited. The shape of the above-mentioned soldering flux may be spherical, or may be other than spherical, such as flat.

When the said electrically-conductive material has the said 2nd structure, the composition which removed the said electroconductive particle from the said electrically-conductive material is colloid. From the viewpoint of more effectively improving the storage stability, more effectively improving the agglomeration of the solder, and more effectively improving the heat resistance of the cured product, it is preferable that the entire composition is a colloid. The above-mentioned composition only needs to contain a part that is a colloid, and the whole composition does not have to be a colloid.

When the above-mentioned conductive material has the above-mentioned second structure, the above-mentioned flux exists in the form of colloidal particles. From the viewpoint of more effectively improving the storage stability, more effectively improving the cohesiveness of the solder, and more effectively improving the heat resistance of the hardened product, the above-mentioned flux is preferably colloidal particles, and the above-mentioned flux is more Colloidal particles having the above-mentioned average particle diameter in the above-mentioned composition are preferable. From the viewpoint of more effectively improving the storage stability, more effectively improving the agglomeration of the solder, and more effectively improving the heat resistance of the hardened product, the above-mentioned flux is preferably dispersed in the above-mentioned composition, The above-mentioned flux is more preferably uniformly dispersed in the above-mentioned composition. Among the above-mentioned conductive materials, preferably more than 20% of the total number of fluxes are colloidal particles. In the above-mentioned conductive material, it is only necessary for a part of the flux to be colloidal particles, and not all of the flux may be colloidal particles.

As a method for confirming that the above-mentioned composition is a colloid, a method of observing Tyndall phenomenon using the above-mentioned composition or a mixture of the above-mentioned composition and a solvent that does not dissolve the above-mentioned flux may be mentioned.

Examples of the aforementioned fluxes include: zinc chloride, mixtures of zinc chloride and inorganic halides, mixtures of zinc chloride and inorganic acids, molten salts, phosphoric acid, derivatives of phosphoric acid, organic halides, hydrazine, organic acids And turpentine etc. The above fluxes may be used alone or in combination of two or more.

Ammonium chloride etc. are mentioned as said molten salt. Lactic acid, citric acid, stearic acid, glutamic acid, malic acid, glutaric acid etc. are mentioned as said organic acid. As said rosin, activated rosin, non-activated rosin, etc. are mentioned. The aforementioned flux is preferably an organic acid having two or more carboxyl groups, or rosin. The above-mentioned flux may be an organic acid having two or more carboxyl groups, or may be rosin. By using an organic acid or rosin having two or more carboxyl groups, the conduction reliability between electrodes becomes higher.

The above-mentioned rosin is a rosin having abietic acid as a main component. The above flux is preferably rosin, more preferably abietic acid. By using this preferred flux, the conduction reliability between electrodes becomes higher.

The melting point (activation temperature) of the above-mentioned soldering flux is preferably at least 50°C, more preferably at least 70°C, further preferably at least 80°C, and preferably at most 200°C, more preferably at most 190°C, and still more preferably at least 190°C. 160°C or lower, more preferably 150°C or lower, still more preferably 140°C or lower. If the melting point (activation temperature) of the said flux is more than the said minimum and below the said upper limit, the flux effect will be exhibited more effectively, and the solder in electroconductive particle will be arrange|positioned on an electrode more efficiently. The melting point (activation temperature) of the above-mentioned flux is preferably not less than 60°C and not more than 190°C. The melting point (activation temperature) of the above-mentioned flux is more preferably 80°C or higher and 140°C or lower.

Examples of the fluxes whose active temperature (melting point) is 60°C to 190°C include: succinic acid (melting point 186°C), glutaric acid (melting point 96°C), adipic acid (melting point 152°C) ), pimelic acid (melting point 104°C), suberic acid (melting point 142°C) and other dicarboxylic acids, benzoic acid (melting point 122°C), malic acid (melting point 130°C), etc.

In addition, the boiling point of the above-mentioned flux is preferably 200° C. or lower.

The above-mentioned flux is preferably a flux that releases cations by heating. By using the flux which releases a cation by heating, the solder in electroconductive particle can be arrange|positioned more efficiently on an electrode.

Examples of the flux that releases cations by heating include the aforementioned thermal cation curing agents.

The above flux is more preferably a salt of an acid compound and an alkali compound. The above-mentioned acid compound preferably has the effect of cleaning the surface of the metal, and the above-mentioned alkali compound preferably has the effect of neutralizing the above-mentioned acid compound. The above-mentioned flux is preferably a neutralization reactant of the above-mentioned acid compound and the above-mentioned alkali compound. The above fluxes may be used alone or in combination of two or more.

From the viewpoint of more efficiently disposing the solder in the conductive particles on the electrodes, the melting point of the flux is preferably lower than the melting point of the solder in the conductive particles, more preferably 5° C. or more lower, and further lower than the melting point of the solder in the conductive particles. It is preferably lower than 10°C. However, the melting point of the said flux may be higher than the melting point of the solder in the said electroconductive particle. Usually, the use temperature of the above-mentioned conductive material is higher than the melting point of the solder in the above-mentioned conductive particles, and if the melting point of the above-mentioned flux is below the use temperature of the above-mentioned conductive material, even if the melting point of the above-mentioned flux The melting point of the solder, the above-mentioned flux can also fully exert its performance as a flux. For example, when the use temperature of conductive materials is above 150°C, it includes solder (Sn ₄₂ Bi ₅₈ : melting point 139°C) in conductive particles, and flux (melting point 146°C) as a salt of malic acid and benzylamine. Among the materials, the above-mentioned flux, which is a salt of malic acid and benzylamine, sufficiently exhibited a fluxing effect.

From the viewpoint of efficiently disposing the solder in the conductive particles on the electrodes, the melting point of the flux is preferably lower than the reaction initiation temperature of the thermosetting agent, more preferably 5°C or more lower, and furthermore It is preferably lower than 10°C.

The above-mentioned acid compound is preferably an organic compound having a carboxyl group. Examples of the acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, Malic acid; cyclohexyl carboxylic acid, 1,4-cyclohexyl dicarboxylic acid as cycloaliphatic carboxylic acid; isophthalic acid, terephthalic acid, trimellitic acid and ethylenediamine as aromatic carboxylic acid Tetraacetic acid, etc. The above acid compound is preferably glutaric acid, azelaic acid or malic acid.

The above-mentioned base compound is preferably an organic compound having an amino group. Examples of the base compound include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, and 2-methylbenzylamine. , 3-methylbenzylamine, 4-tert-butylbenzylamine, N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine amine, N-isopropylbenzylamine, N,N-dimethylbenzylamine, imidazole compound and triazole compound. The aforementioned base compound is preferably benzylamine, 2-methylbenzylamine or 3-methylbenzylamine.

The above flux can be dispersed in the conductive material, and can also be attached to the surface of the conductive particles. From the viewpoint of enhancing the flux effect more effectively, it is preferable that the above-mentioned flux adheres to the surface of the electroconductive particle.

The flux satisfying the above-mentioned 1a structure, the above-mentioned 1b structure, and the above-mentioned 2nd structure can be obtained, for example by melting a solid flux and then re-precipitating it. It is preferable to perform reprecipitation smoothly. The method of obtaining the above-mentioned flux is preferably a method of heating the solid flux above the melting point to completely melt the flux. The method of obtaining the above-mentioned flux is preferably a method of slowly re-precipitating the molten flux. By the above-mentioned method, uniform flux having the above-mentioned average particle size can be easily obtained.

As another method of obtaining flux with a relatively small average particle size, for example, a method of pulverizing solid flux is mentioned. However, in the method of pulverizing the solid flux, there is a limit to reducing the average particle diameter of the flux, and it is difficult to obtain a flux having the above-mentioned average particle diameter. Furthermore, after pulverizing the flux, the fluxes coagulate with each other, and it is easy to become a non-uniform flux. Inhomogeneous flux (crushed flux) is difficult to disperse evenly in conductive materials. When using uneven flux, in order to improve the cohesion of solder, the content of flux in conductive materials tends to become relatively more. As a result, the storage stability of the conductive material decreases, and the heat resistance of the cured product of the conductive material decreases, making it difficult to obtain the effects of the present invention. Therefore, the above-mentioned flux is preferably obtained by a method other than pulverizing solid flux, preferably by melting solid flux whose re-precipitation rate is relatively slow, and then re-precipitating it.

From the standpoint of more effectively improving the storage stability, more effectively improving the agglomeration of the solder, and more effectively improving the heat resistance of the cured product, the amount of the above-mentioned flux The content is preferably not less than 1 part by weight, more preferably not less than 2 parts by weight, and preferably not more than 20 parts by weight, more preferably not more than 15 parts by weight.

From the standpoint of more effectively improving the storage stability, more effectively improving the agglomeration of the solder, and more effectively improving the heat resistance of the hardened product, in 100% by weight of the above-mentioned conductive material, the amount of the above-mentioned flux The content is preferably at least 0.05% by weight, more preferably at least 2% by weight, and is preferably at most 20% by weight, more preferably at most 15% by weight. Also, if the content of the above-mentioned flux is more than the above-mentioned lower limit and below the above-mentioned upper limit, it is more difficult to form an oxide film on the surface of the solder in the conductive particles and the electrode, and furthermore, the solder formed in the conductive particles can be removed more effectively. And the oxide film on the surface of the electrode.

(Filler) A filler may be added to the above-mentioned conductive material. Fillers can be organic fillers or inorganic fillers. By adding fillers, conductive particles can be uniformly aggregated on all electrodes of the substrate.

The above-mentioned conductive material preferably does not contain the above-mentioned filler, or contains the above-mentioned filler in an amount of 5% by weight or less. In the case of using a crystalline thermosetting compound, the smaller the content of the filler, the easier it is for the solder to move to the electrodes.

In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned filler is preferably not less than 0% by weight (not contained), and preferably not more than 5% by weight, more preferably not more than 2% by weight, and more preferably not more than 1% by weight . Electroconductive particle is arrange|positioned on an electrode more efficiently as content of the said filler is more than the said minimum and below the said upper limit.

(Other components) The above-mentioned conductive materials may also optionally include fillers, extenders, softeners, plasticizers, polymerization catalysts, hardening catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet rays, etc. Various additives such as absorbents, lubricants, antistatic agents and flame retardants.

(Connection Structure) The connection structure of the present invention includes: a first member to be connected, which has a first electrode on its surface; a second member to be connected, which has a second electrode on its surface; The first connection object member is connected to the second connection object member. In the connection structure of this invention, the material of the said connection part is the said conductive material. In the connection structure of this invention, the said connection part is hardened|cured material of the said conductive material. In the connection structure of this invention, the said connection part is formed with the said conductive material. In the connection structure of this invention, the said 1st electrode and the said 2nd electrode are electrically connected by the solder part in the said connection part.

In the connection structure of the present invention, since a specific conductive material is used, the solder in the conductive particles is easily gathered between the first electrode and the second electrode, and the solder can be efficiently arranged on the electrodes (lines). In addition, part of the solder is not easily disposed in the region (gap) where the electrode is not formed, so that the amount of solder disposed in the region where the electrode is not formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. Furthermore, electrical connection between laterally adjacent electrodes that should not be connected can be prevented, and insulation reliability can be improved.

In addition, in order to efficiently arrange the solder in the conductive particles on the electrodes and to reduce the amount of solder disposed in the region where the electrodes are not formed, it is preferable to use a conductive paste instead of a conductive film as the conductive material.

The thickness of the solder portion between the electrodes is preferably at least 10 μm, more preferably at least 20 μm, and preferably at most 100 μm, more preferably at most 80 μm. The solder wetting area on the surface of the electrode (the area exposed to the solder in 100% of the area of the electrode) is preferably 50% or more, more preferably 60% or more, further preferably 70% or more, and more preferably 100% %the following.

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

Fig. 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 is equipped with the 1st connection object member 2, the 2nd connection object member 3, and the connection part 4 which connects the 1st connection object member 2 and the 2nd connection object member 3. As shown in FIG. The connecting portion 4 is formed of the above-mentioned conductive material. In this embodiment, the conductive material includes conductive particles, a thermosetting compound, and flux. In this embodiment, solder particles are included as the above-mentioned electroconductive particles. The aforementioned thermosetting compound, the aforementioned thermosetting agent, and the aforementioned flux are referred to as thermosetting components.

The connection part 4 has a solder part 4A formed by aggregating and bonding a plurality of solder particles, and a cured part 4B formed by thermosetting a thermosetting component.

The 1st connection object member 2 has some 1st electrode 2a on the surface (upper surface). The 2nd connection object member 3 has some 2nd electrode 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 part 4, the solder does not exist in the area|region (cured part part 4B part) different from the solder part 4A gathered between the 1st electrode 2a and the 2nd electrode 3a. There is no solder separated from the solder portion 4A in a region (hardened portion 4B portion) different from the solder portion 4A. Furthermore, if it is a small amount, solder may exist in the area|region (cured part part 4B part) different from the solder part 4A gathered between the 1st electrode 2a and the 2nd electrode 3a.

As shown in Fig. 1, in the connection structure 1, a plurality of solder particles are gathered between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the molten material of the solder particles wets and spreads on the surface of the electrodes. After curing, the solder portion 4A is formed. Therefore, the connection area between 4 A of solder parts and the 1st electrode 2a, and 4 A of solder parts and the 2nd electrode 3a becomes large. That is, by using solder particles, the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 2a will be more stable than the case where the outer surface portion of the conductive portion is made of conductive particles made of metals such as nickel, gold, or copper. The contact area of 3a becomes larger. Therefore, conduction reliability and connection reliability in the connection structure 1 become high. Furthermore, the flux contained in the conductive material is generally gradually inactivated by heating.

In addition, in the connection structure 1 shown in FIG. 1, the whole of 4 A of solder parts is located in the area|region which opposes between 1st, 2nd electrode 2a, 3a. The connection structure 1X of the modification shown in FIG. 3 is different from the connection structure 1 shown in FIG. 1 only in the connection part 4X. The connecting portion 4X has a solder portion 4XA and a cured portion 4XB. Also 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 directed from the area facing the first and second electrodes 2a and 3a. Side overflow. The solder portion 4XA that overflows laterally from the area where the first and second electrodes 2a, 3a face each other is part of the solder portion 4XA, and is 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 the solder separated from the solder portion may exist in the cured product portion.

If the amount of solder particles used is reduced, the connection structure 1 can be easily obtained. When the usage-amount of a solder particle increases, it becomes easy to obtain connection structure 1X.

A portion where the first electrode and the second electrode face each other is observed in the lamination direction of the first electrode, the connection portion, and the second electrode. In this case, from the viewpoint of further improving conduction reliability, it is preferable that 50% or more (more preferably 60% or more) of 100% of the area of the portion where the first electrode and the second electrode face each other , and more preferably more than 70%, more preferably more than 80%, most preferably more than 90%) are configured with the solder portion in the above-mentioned connecting portion.

Next, an example of the method of manufacturing the connection structure 1 using the electrically-conductive material which concerns on one Embodiment of this invention is demonstrated.

First, the 1st connection object member 2 which has the 1st electrode 2a on the surface (upper surface) is prepared. Next, as shown in FIG. 2( a ), conductive material 11 including thermosetting component 11B and a plurality of solder particles 11A is disposed on the surface of first connection object member 2 (first step). The conductive material 11 contains a thermosetting compound, a thermosetting agent, and flux as a thermosetting component 11B.

The conductive material 11 is arranged on the surface of the first connection object member 2 on which 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.

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

Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in Figure 2 (b), in the conductive material 11 on the surface of the first connection object member 2, the second surface is arranged on the surface of the conductive material 11 opposite to the first connection object member 2 side. Connect object member 3 (2nd step). On the surface of the conductive material 11, the 2nd connection object member 3 is arrange|positioned from the 2nd electrode 3a side. At this time, the 1st electrode 2a and the 2nd electrode 3a are made to oppose.

Next, the conductive material 11 is heated to a temperature equal to or higher than the melting point of the solder particles 11A (third step). It is preferable to heat the conductive material 11 above the hardening temperature of the thermosetting component 11B (thermosetting compound). At the time of this heating, 11 A of solder particles which exist in the area|region where an electrode is not formed gather between the 1st electrode 2a and the 2nd electrode 3a (self-aggregation effect). When 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 bonded to each other. Also, the thermosetting component 11B undergoes thermosetting. 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 part 4 is formed of the conductive material 11, the solder part 4A is formed by bonding a plurality of solder particles 11A, and the cured part 4B is formed by thermosetting the thermosetting component 11B. If the solder particle 11A moves sufficiently, the solder particle 11A can be completed between the first electrode 2a and the second electrode 3a from the start of the movement of the solder particle 11A not located between the first electrode 2a and the second electrode 3a. Before moving, do not keep the temperature constant.

In this embodiment, it is preferable not to pressurize in the said 2nd process and the said 3rd process. In this case, the weight of the second connection object member 3 is applied to the conductive material 11 . Therefore, when forming the connection part 4, 11 A of solder particles gather more effectively between the 1st electrode 2a and the 2nd electrode 3a. Furthermore, when the pressure is applied in at least one of the above-mentioned second step and the above-mentioned third step, the tendency to inhibit the action of the solder particles 11A to gather between the first electrode 2 a and the second electrode 3 a becomes high.

When the second connection object member is superimposed on the first connection object member coated with a conductive material, there is a state where the electrodes of the first connection object member and the electrodes of the second connection object member are misaligned, and the superimposed second connection object member 1. The case where the member to be connected is connected to the second member to be connected. In this embodiment, since no pressure is applied, this offset can be corrected, and the electrode of the first connection object member can be connected to the electrode of the second connection object member (self-alignment effect). The reason is that the molten solder agglomerated between the electrode of the first connection object member and the electrode of the second connection object member is the solder between the electrode of the first connection object member and the electrode of the second connection object member. The energy becomes stable when the contact area of other components of the material is minimized. And this is because the force applied to the connection structure which becomes the alignment of the connection structure which becomes this minimum area acts. At this time, it is preferable that the conductive material is not hardened, and that the viscosity of the components other than the conductive particles of the conductive material is sufficiently low at the temperature and time.

The viscosity of the conductive material at the melting point of the solder is preferably not more than 50 Pa·s, more preferably not more than 10 Pa·s, further preferably not more than 1 Pa·s, more preferably not less than 0.1 Pa·s, more preferably 0.2 Pa・s or more. The solder in electroconductive particle can be aggregated efficiently that the said viscosity is below the said upper limit. When the said viscosity is more than the said minimum, the porosity of a connection part can be suppressed, and the overflow of a conductive material to the outside of a connection part can be suppressed.

The viscosity of the conductive material at the melting point of the solder is measured in the following manner.

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

In this way, the connection structure 1 shown in FIG. 1 is obtained. In addition, the above-mentioned second step and the above-mentioned third step may be continuously performed. In addition, 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 part to perform the above-mentioned third step. In order to carry out the above-mentioned heating, the above-mentioned laminated body may be arranged on a heating member, or the above-mentioned laminated body may be arranged in a heated space.

The heating temperature in the third step is preferably at least 140°C, more preferably at least 160°C, more preferably at most 450°C, more preferably at most 250°C, further preferably at most 200°C.

As the heating method in the above-mentioned third step, the following method can be mentioned: using a reflow furnace or using an oven to heat the entire connection structure to a temperature above the melting point of the solder in the conductive particles and above the hardening temperature of the thermosetting component; or only The connection part of the connection structure is locally heated.

Examples of the device used in the method of locally heating include a hot plate, a heat gun for applying hot air, a soldering iron, and an infrared heater.

In addition, when heating locally with a heating plate, it is preferable to form the upper surface of the heating plate with a metal with high thermal conductivity directly below the connecting portion, and it is preferable to use a thermally conductive metal such as a fluororesin for other parts not to be heated. The lower material forms the upper surface of the heating plate.

The above-mentioned first and second connection object members are not particularly limited. As the above-mentioned first and second connection object members, specifically, electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors, and diodes; resin films, printed circuit boards, flexible printed circuit boards, etc.; Substrates, flexible flat cables, rigid flexible substrates, glass epoxy substrates, and electronic components such as circuit substrates such as glass substrates, etc. It is preferable that the said 1st, 2nd connection object member is an electronic component.

Preferably, at least one of the first connection target member and the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. Preferably, at least one of the first connection target member and the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. Resin films, flexible printed substrates, flexible flat cables, and rigid flexible substrates are highly flexible and relatively lightweight. When a conductive film is used for the connection of such connection target members, it tends to be difficult for solder to gather on the electrodes. In contrast, by using conductive paste, even if resin film, flexible printed circuit board, flexible flat cable or rigid flexible substrate is used, solder can be efficiently gathered on the electrodes, thereby fully improving the conduction reliability between electrodes sex. When using a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate, compared with the case of using other connection object members such as semiconductor chips, it is more effective to obtain the gap between electrodes caused by not applying pressure. Improvement of conduction reliability.

Examples of electrodes provided on the member to be connected include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the above-mentioned member to be connected is a flexible printed circuit board, the above-mentioned 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. Furthermore, when the above-mentioned electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or may be an electrode in which an aluminum layer is deposited on the surface of the metal oxide layer. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element, zinc oxide doped with a trivalent metal element, and the like. As said trivalent metal element, Sn, Al, Ga, etc. are mentioned.

Hereinafter, an Example and a comparative example are given, and this invention is demonstrated concretely. The present invention is not limited to the following examples.

Thermosetting compound: "jER 152" manufactured by Mitsubishi Chemical Co., Ltd., epoxy resin

Thermosetting agent (thermal curing accelerator (catalyst)): "BF3-MEA" manufactured by Stella Chemifa Co., Ltd., boron trifluoride-monoethylamine complex

Conductive particle: "Sn ₄₂ Bi ₅₈ (DS-10)" manufactured by Mitsui Metal Mining Co., Ltd.

Flux: (1) Flux 1 Preparation method of flux 1: Put 24 g of water and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a reaction solvent in a glass bottle, and make the Wait until dissolved until homogeneous. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a liquid mixture. The obtained mixture was put into a refrigerator at 5-10° C. for one night. The precipitated crystal was fractionated by filtration, washed with water, and vacuum-dried. The dried crystals were heated at 140°C for 15 minutes to completely melt them, and then slowly re-precipitated at 25°C for 30 minutes, thereby obtaining flux 1.

(2) Flux 2 The preparation method of flux 2: Put 24 g of water and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a reaction solvent in a glass bottle, and dissolve them at room temperature until become even. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a liquid mixture. The obtained mixture was put into a refrigerator at 5-10° C. for one night. The precipitated crystal was fractionated by filtration, washed with water, and vacuum-dried. The dried crystals were heated at 160° C. for 5 minutes to completely melt them, and then slowly re-precipitated at 25° C. for 30 minutes to obtain flux 2 .

(3) Flux 3 The preparation method of flux 3: Put 24 g of water and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a reaction solvent in a glass bottle, and dissolve them at room temperature until become even. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a liquid mixture. The obtained mixture was put into a refrigerator at 5-10° C. for one night. The precipitated crystal was fractionated by filtration, washed with water, and vacuum-dried. The dried crystals were pulverized with a mortar to obtain flux 3 .

(4) Flux 4 The preparation method of flux 4: Put 24 g of water and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a reaction solvent in a glass bottle, and dissolve them at room temperature until become even. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a liquid mixture. The obtained mixture was put into a refrigerator at 5-10° C. for one night. The precipitated crystal was fractionated by filtration, washed with water, and vacuum-dried. The dried crystals were pulverized with a jet mill pulverizer manufactured by Nisshin Engineering Co., Ltd., thereby obtaining flux 4 .

(Examples 1-2 and Comparative Examples 1-3) (1) Preparation of conductive material (anisotropic conductive paste) The ingredients shown in the following Table 1 were prepared in the amounts shown in the following Table 1 to obtain the conductive material ( anisotropic conductive paste).

(2) Production of the first connection structure (L/S=50 μm/50 μm) Using the conductive material (anisotropic conductive paste) immediately after production, the first connection structure was produced as follows.

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

The overlapping area of the above-mentioned glass epoxy substrate and the above-mentioned flexible printed substrate was set to 1.5 cm×3 mm, and the number of connected electrodes was set to 75 pairs.

On the upper surface of the above-mentioned glass epoxy substrate, on the electrodes of the glass epoxy substrate, a metal mask was used to form a thickness of 100 μm, and a conductive material (anisotropic conductive material) just after production was applied by screen printing. paste) to form a layer of conductive material (anisotropic conductive paste). Next, the above-mentioned flexible printed circuit board is laminated on the upper surface of the conductive material (anisotropic conductive paste) layer in such a manner that the electrodes face each other. At this time, pressurization was not performed. The above weight of the flexible printed substrate is applied to the conductive material (anisotropic conductive paste) layer. From this state, heating was performed so that the temperature of the conductive material (anisotropic conductive paste) layer became 139° C. (melting point of solder) 5 seconds after the start of heating. Furthermore, heating was performed so that the temperature of the conductive material (anisotropic conductive paste) layer became 160° C. after 15 seconds from the start of heating, and the conductive material (anisotropic conductive paste) layer was cured to obtain a connected structure. During heating, no pressurization was performed.

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

A second connection structure was obtained in the same manner as the production of the first connection structure except that the glass epoxy substrate and the flexible printed circuit board having different L/S were used.

(4) Preparation of the third connection structure (L/S = 100 μm/100 μm) The L/S is 100 μm/100 μm, and the copper electrode pattern with an electrode length of 3 mm is provided on the upper surface (the thickness of the copper electrode is 12 μm) glass epoxy substrate (FR-4 substrate) (first connection object member). Also, a flexible printed circuit board (second connection object member) having an L/S of 100 μm/100 μm and a copper electrode pattern (copper electrode thickness 12 μm) having an electrode length of 3 mm on the lower surface was prepared.

A third connection structure was obtained in the same manner as the preparation of the first connection structure except that the glass epoxy substrate and the flexible printed circuit board having different L/S were used.

(Evaluation) (1) Existing state of flux Using a laser microscope ("OLS4100" manufactured by Olympus), measure the particle diameter of 50 arbitrary fluxes, and calculate the average particle diameter of the obtained flux from the average value .

Based on the average particle size of the obtained flux, calculate the ratio of the number of fluxes having a particle size twice or more the average particle size of the flux in 100% of the total number of fluxes, and the ratio of the number of fluxes to the total number of flux The ratio of the number of fluxes having a particle size of 1.5 times or more the average particle size of the flux in 100%.

(2) Colloid By filtering the obtained conductive material (anisotropic conductive paste), conductive particles were removed from the conductive material (anisotropic conductive paste). Put the composition after removing the conductive particles into a 10 mL spiral tube, and irradiate the laser pointer from the horizontal direction of the spiral tube to confirm whether Tyndall phenomenon caused by the flux is observed. Colloids are judged according to the following criteria. Furthermore, it was confirmed that the thermosetting compound and the thermosetting agent were dissolved.

[Judgment criteria for colloids] ○: Tyndall phenomenon caused by flux is observed ×: Tyndall phenomenon caused by flux is not observed

(3) Storage stability Measure the viscosity (η1) of the conductive material (anisotropic conductive paste) at 25°C immediately after production. In addition, the conductive material (anisotropic conductive paste) just after production was placed at room temperature for 24 hours, and the viscosity (η2) of the conductive material (anisotropic conductive paste) at 25°C was measured after standing. The above viscosity was measured using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25°C and 5 rpm. Calculate the viscosity increase rate (η2/η1) based on the measured value of the viscosity. Storage stability was judged according to the following criteria.

[Criteria for judging storage stability] ○: Ratio of viscosity increase (η2/η1) is 1.5 or less △: Ratio of viscosity increase (η2/η1) exceeds 1.5 and is less than 2.0 ×: Ratio of viscosity increase (η2/η1) exceeds 2.0

(4) Heat resistance of cured product The obtained conductive material (anisotropic conductive paste) was heated at 150°C for 2 hours, whereby a cured product was obtained. Using a dynamic viscoelasticity measuring device ("Rheogel-E" manufactured by UBM Corporation), the glass transition temperature (Tg) of the obtained cured product was measured at a heating rate of 10° C./min. The heat resistance of the cured product was judged according to the following criteria.

[Criteria for judging heat resistance of cured product] ○: Tg of cured product is 100°C or higher △: Tg of cured product is 90°C or higher and less than 100°C ×: Tg of cured product is less than 90°C

(5) The placement accuracy of the solder on the electrodes (agglomeration of the solder) was evaluated in the lamination direction of the first electrode, the connection part, and the second electrode in the obtained first, second, and third connection structures When looking at the portion where the first electrode and the second electrode face each other, the ratio X of the area where the solder portion in the connecting portion is arranged in 100% of the area of the portion where the first electrode and the second electrode face each other. The placement accuracy of the solder on the electrodes (aggregation of the solder) was judged according to the following criteria.

[Criteria for judging the placement accuracy of the solder on the electrode (aggregation of the solder)] ○○: Ratio X is 70% or more ○: Ratio X is 60% or more and less than 70% △: Ratio X is 50% or more and not Up to 60% ×: Ratio X is less than 50%

(6) Conduction reliability between the upper and lower electrodes In the first, second and third connection structures (n=15) obtained, each connection site between the upper and lower electrodes was measured by the four-terminal method The connection resistance. Calculate the average value of the connection resistance. Furthermore, according to the relationship of voltage=current×resistance, the voltage when a certain current flows can be measured to obtain the connection resistance. Conduction reliability was judged according to the following criteria.

[Judgement 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 70 mΩ or less △: The average value of the connection resistance exceeds 70 mΩ and is 100 mΩ or less ×: The average value of connection resistance exceeds 100 mΩ, or poor connection occurs

(7) Insulation reliability between laterally adjacent electrodes After placing the first, second and third connection structures (n=15) in an environment of 85°C and 85% humidity for 100 hours, Apply 5 V between laterally adjacent electrodes, and measure the resistance value at 25. Insulation reliability was judged according to the following criteria.

[Criteria for judging 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 More than but less than 10 ⁶ Ω ×: The average value of connection resistance is less than 10 ⁵ Ω

The results are shown in Table 1 below.

[Table 1]

Even when a resin film, a flexible flat cable, and a rigid flexible substrate are used instead of a flexible printed circuit board, the same tendency is seen.

1‧‧‧connection structure 1X‧‧‧connection structure 2‧‧‧first connection object member 2a‧‧‧first electrode 3‧‧‧second connection object member 3a‧‧‧second electrode 4‧‧‧ Connection part 4X‧‧‧Connection part 4A‧‧‧Solder part 4XA‧‧‧Solder part 4B‧‧‧Hardened part 4XB‧‧‧Hardened part 11‧‧‧Conductive material 11A‧‧‧Solder particle (conductive particle )11B‧‧‧thermosetting component 21‧‧‧conductive particle (solder particle) 31‧‧‧conductive particle 32‧‧‧substrate particle 33‧‧‧conductive part (conductive part with solder) 33A‧‧ ‧Second conductive part 33B‧‧‧Solder part 41‧‧Conductive particles 42‧‧‧Solder part

Fig. 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 for explaining each step of an example of a method of manufacturing a connection structure using a conductive material according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing a modified example of the connection structure. Fig. 4 is a cross-sectional view showing a first example of conductive particles that can be used as a conductive material. Fig. 5 is a cross-sectional view showing a second example of conductive particles that can be used as a conductive material. Fig. 6 is a cross-sectional view showing a third example of conductive particles that can be used as a conductive material.

1‧‧‧connection structure

2‧‧‧The first connection object component

2a‧‧‧1st electrode

3‧‧‧The second connection target member

3a‧‧‧Second electrode

4‧‧‧connection part

4A‧‧‧Solder Department

4B‧‧‧hardening department

Claims (8)

A conductive material, which includes a plurality of conductive particles with solder on the outer surface of the conductive part, a thermosetting compound and flux, the viscosity at 25°C is not less than 20Pa‧s and not more than 500Pa‧s, and has the following Either one or more of the first composition and the second composition: the first composition: there is no flux having a particle diameter more than twice the average particle diameter of the above-mentioned flux, or the total number of the above-mentioned fluxes is 100 %, the number of fluxes having a particle size twice or more the average particle size of the above-mentioned flux is present in less than 10%; the second composition: the composition obtained by removing the above-mentioned conductive particles from the above-mentioned conductive material is a colloid , the above flux exists in the form of colloidal particles. The conductive material according to claim 1, wherein there is no flux having a particle diameter more than 1.5 times the average particle diameter of the above-mentioned flux, or the average particle size of the above-mentioned flux is present in 100% of the total number of the above-mentioned fluxes Less than 20% of fluxes with particle diameters greater than 1.5 times the diameter exist. The conductive material according to claim 1 or 2, wherein the average particle size of the above-mentioned soldering flux is 1 μm or less. The conductive material according to claim 1 or 2, wherein the content of the flux is 1 part by weight to 20 parts by weight relative to 100 parts by weight of the thermosetting compound. The conductive material according to claim 1 or 2, wherein 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. As the conductive material of claim 1 or 2, it is a conductive paste. A connection structure comprising: a first connection object member having a first electrode on its surface; a second connection object member having a second electrode on its surface; and a connecting portion that connects the above first connection object The component is connected to the above-mentioned second connection object component; and the material of the above-mentioned connection part is a conductive material such as any one of claims 1 to 6, and the above-mentioned first electrode and the above-mentioned second electrode are electrically connected by the solder part in the above-mentioned connection part. sexual connection. The connection structure according to claim 7, wherein when the part of the first electrode and the second electrode facing each other is observed in the lamination direction of the first electrode, the connection part, and the second electrode, in the first electrode More than 50% of 100% of the area of the portion where the electrode and the second electrode are opposed to each other is provided with the solder portion in the connection portion.

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