TW201903787A - Conductive material and connection structure - Google Patents

Abstract

Provided is an electroconductive material in which it is possible to effectively increase the storage stability of the electroconductive material, to effectively increase the cohesiveness of solder during electroconductive connection, and furthermore, to effectively increase the heat resistance of a cured product. The electroconductive material according to the present invention contains a plurality of electrically conductive particles having solder on an outer surface portion of an electrically conductive part, a thermosetting compound, and flux, the electroconductive material comprising one or more of a first configuration in which "flux having a particle diameter that is 2 times or more of the average particle diameter of the flux is not present, or flux having a particle diameter that is 2 times or more of the average particle diameter of the flux is present at a number of less than 10% in 100% of the total number of the flux," and a second configuration in which "a composition in which the electrically conductive particles are removed from the electroconductive material is a colloid, and the flux is present as colloidal particles.".

Description

Conductive material and connection structure

The present invention relates to a conductive material including conductive particles having solder on an outer surface portion of a conductive portion. The present invention also relates to a connection structure using the conductive material.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are well known. In the anisotropic conductive material, conductive particles are dispersed in a binder.

The anisotropic conductive material is used to obtain various connection structures. Examples of the connection through the anisotropic conductive material include a connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass, Coated Glass)), a connection between a semiconductor wafer and a flexible printed substrate (COF (Chip on Film) , Film-on-chip)), the connection of semiconductor wafers and glass substrates (COG (Chip on Glass, glass-on-chip)), and the connection of flexible printed substrates and glass epoxy substrates (FOB (Film on Board, coated plate)) .

When the electrodes of the flexible printed circuit board and the electrodes of the glass epoxy substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. Next, the flexible printed circuit board is laminated and heated and pressurized. Thereby, the anisotropic conductive material is hardened, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

As an example of the anisotropic conductive material described below, Patent Document 1 below discloses an anisotropic conductive material containing conductive particles and a resin component that has not been cured at the melting point of the conductive particles. Specific examples of the conductive particles include tin (Sn), indium (In), bismuth (Bi), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), and gallium ( Ga), silver (Ag), osmium (Tl) and other metals, 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 conductive particles and incomplete curing of the resin component, and a resin component hardening step of curing the resin component, Electrically connect the electrodes. In addition, Patent Document 1 describes mounting with a 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.

Further, Patent Document 2 below discloses a solder paste (conductive material) containing a flux and an alloy powder containing tin as a main component. The above-mentioned flux is a flux obtained by adding an active agent to a solvent and dispersing it. The solvent is a polyhydric alcohol having 2 to 4 hydroxyl groups. The active agent is a saccharide having 4 to 6 hydroxyl groups. The average particle diameter 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 soldering flux. The soldering flux includes an epoxy resin and an organic carboxylic acid. The organic carboxylic acid is dispersed as a solid in the solder composition at room temperature (25 ° C). [Prior Art Literature] [Patent Literature]

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

[Problems to be solved by the invention]

In the conventional conductive materials described in Patent Documents 1 to 3, the moving speed of conductive particles or solder particles on the electrodes (wires) is slow, and it is difficult for the solder to efficiently condense on the electrodes to be connected above and below. Between situations. As a result, the conduction reliability and insulation reliability between the electrodes tend to be lowered.

Examples of a method for efficiently soldering the solder to the electrode include a method of increasing the amount of the flux in the conductive material.

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. In addition, if the content of the flux in the conductive material is increased, the heat resistance of the hardened material of the conductive material may be reduced.

In the conventional conductive materials described in Patent Documents 1 to 3, it has been difficult to satisfy all of the requirements for improving the storage stability of conductive materials, improving the cohesiveness of solder during conductive connection, and improving the heat resistance of hardened materials.

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 solder agglutination property during conductive connection, and further effectively improve the heat resistance of the hardened material. Another object of the present invention is to provide a connection structure using the conductive material. [Technical means to solve the problem]

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

The first structure: there is no flux having a particle diameter that is more than two times the average particle diameter of the flux, or that there is more than two times the average particle diameter of the above-mentioned flux in 100% of the total number of the fluxes Fluxes with a particle size of less than 10% are present.

The second configuration: the composition after removing the conductive particles from the conductive material is a colloid, and the flux is in the form of colloid particles.

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

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 based on 100 parts by weight of the thermosetting compound.

In a specific aspect of the conductive material of the present invention, the content of the above-mentioned flux is from 0.05% by weight to 20% by weight in 100% by weight of the conductive material.

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

According to a broad aspect of the present invention, there is provided a connection structure including: a first connection target member having a first electrode on a surface; a second connection target member having a second electrode on a surface; and a connection The first connection target member and the second connection target member are connected; and the material of the connection portion is the conductive material, and the first electrode and the second electrode are electrically connected to each other through a solder portion in the connection portion. Sexual connection.

In a specific aspect of the connection structure of the present invention, a portion where the first electrode and the second electrode face each other is viewed in a direction in which the first electrode, the connection portion, and the second electrode are laminated. At this time, the solder portion of the connection portion is disposed at 50% or more of an area of 100% of a portion where the first electrode and the second electrode face each other. [Effect of the invention]

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

The details of the present invention will be described below.

(Conductive material) The conductive material of the present invention includes a plurality of conductive particles having solder on the outer surface portion of the conductive portion, a thermosetting compound, and a flux. The conductive material of the present invention includes at least one of the following first and second configurations. The conductive material of the present invention may have only the following first configuration, may have only the following second configuration, or may have both the following first configuration and the following second configuration.

The first structure: there is no flux having a particle diameter that is more than two times the average particle diameter of the flux, or that there is more than two times the average particle diameter of the above-mentioned flux in 100% of the total number of the fluxes Flux with a particle size of less than 10%

The second structure: the composition after removing the conductive particles from the conductive material is a colloid, and the flux is in the form of colloid particles

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

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

Since the present invention has the above-mentioned structure, the storage stability of the conductive material can be improved, the cohesiveness of the solder at the time of conductive connection can be effectively improved, and the heat resistance of the hardened material can be effectively improved.

Since the present invention has the above-mentioned structure, in the case of electrically connecting electrodes, a plurality of conductive particles can be efficiently arranged on the electrodes (wires), and the solder can be efficiently aggregated above and below the connection to be connected. Between electrodes. In addition, it is difficult to arrange a part of the plurality of conductive particles in a region (gap) where no electrode is formed, and the amount of conductive particles arranged in a region where no electrode is formed can be made relatively small. Therefore, the conduction reliability between the electrodes can be improved. In addition, it can prevent the electrical connection between the laterally adjacent electrodes that should not be connected, and can improve the insulation reliability.

Flux is mainly formulated in conductive materials in order to remove oxides existing on the surface of solder and electrodes on conductive particles, or to prevent the formation of such oxides. In the present invention, the flux is relatively difficult to aggregate, and the particle size of the flux is relatively small. Furthermore, in the present invention, the flux is relatively well dispersed. Therefore, in the present invention, even if the content of the flux in the conductive material is relatively small, the oxide existing on the surface of the solder in the conductive particles and the surface of the electrode can be removed, and the formation of the oxide can be prevented. In the present invention, even if the content of the flux in the conductive material is relatively small, the cohesiveness of the solder during the conductive connection can be effectively improved. In the present invention, the content of the flux in the conductive material can be made relatively small.

When the flux is compared in the same content, the conductive connection can be effectively improved in the case where the flux is in the present state compared to the case where the flux is not in the present state. Aggregation of the solder.

In the present invention, the content of the flux in the conductive material may not be set to a large amount, and may be set to a relatively small amount, so the reaction between the thermosetting compound and the flux in the conductive material can be effectively suppressed. As a result, the storage stability of the conductive material can be effectively improved.

In addition, the melting point (active temperature) of the flux in the conductive material is often lower than the Tg of the thermosetting compound in the conductive material. The more the content of the flux in the conductive material, the more heat resistant the hardened material of the conductive material is. The tendency to decrease sex. In the present invention, the content of the flux in the conductive material may not be set to a large amount, and may be set to a relatively small amount, so the heat resistance of the hardened material of the conductive material may be effectively improved.

Since the present invention has the above-mentioned structure, it can meet all the requirements of improving the storage stability of conductive materials, improving the agglutination of solder during conductive connection, and improving the heat resistance of hardened materials.

Furthermore, in the present invention, it is possible to prevent a positional shift between the electrodes. During the conductive connection, the second connection target member is overlapped with the first connection target member having the conductive material disposed on the upper surface. In this case, even when the first connection target member and the second connection target member are misaligned, the first connection target member and the second connection target member are overlapped, in the present invention You can also correct the offset. As a result, the electrode of the first connection target member and the electrode of the second connection target member can be connected (self-aligned effect).

From the viewpoint of further improving the cohesiveness of the solder, the conductive material is preferably liquid at 25 ° C, and is more preferably a conductive paste.

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

The viscosity (η25) can be measured, for example, using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) and the like at 25 ° C and 5 rpm.

The conductive material may be used in the form of a conductive paste, a conductive film, or the like. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. From the viewpoint of further improving the cohesiveness of the solder, the conductive material is preferably a conductive paste. The conductive material is preferably used for the electrical connection of the electrodes. The 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 one or both of "acrylic acid" and "methacrylic acid", and "(meth) acrylate" means "acrylate" and "formaldehyde" One or both.

(Conductive particle) The said conductive particle electrically connects the electrodes of the connection target member. The conductive particles have solder on the outer surface of the conductive portion. The conductive particles may be solder particles made of solder. The solder particles have solder on an outer surface portion of the conductive portion. Both the central portion of the solder particle system and the outer surface portion of the conductive portion are formed of solder. The solder particles are particles of solder at the central portion and the outer conductive surface. The said conductive particle may have a base material particle and the electroconductive part arrange | positioned on the surface of this base material particle. In this case, the conductive particles have solder on the outer surface portion of the conductive portion.

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

Furthermore, compared with the case where the said solder particle is used, when using the conductive particle which has the base material particle which is not formed with solder, and the solder part arrange | positioned on the surface of this base material particle, it is difficult for a conductive particle. Gather on the electrode. Furthermore, since the conductive particles have low weldability to each other, the conductive particles that have moved to the electrodes tend to easily move outside the electrodes, and the effect of suppressing the positional shift between the electrodes also tends to be low. Therefore, the conductive particles are preferably solder particles made of solder.

Next, specific examples of conductive 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 for a conductive material.

The conductive particles 21 shown in FIG. 4 are solder particles. The entire conductive particles 21 are made of solder. The conductive particles 21 are particles having no base material in the core, and are not core-shell particles. Both the central portion of the conductive particles 21 and the outer surface portion of the conductive portion are formed of solder.

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

The conductive particles 31 shown in FIG. 5 include substrate particles 32 and a conductive portion 33 disposed on the surface of the substrate particles 32. The conductive portion 33 covers the surface of the substrate particles 32. The conductive particles 31 are coated particles whose surfaces are covered with the conductive portions 33 by the substrate particles 32.

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

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

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

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

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

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

When the electrodes are connected using the conductive particles, the conductive particles are arranged between the electrodes and then pressure-bonded to compress the conductive particles. When the substrate particles are resin particles or organic-inorganic mixed particles, the conductive particles are easily deformed during the compression bonding, and the contact area between the conductive particles and the electrode becomes large. Therefore, the conduction reliability between the electrodes becomes higher.

As the material of the resin particles, various resins are preferably used. Examples of the material of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; polymethylmethacrylate, 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, polyfluorene, polyphenylene ether, polyacetal, polyimide, polyimide, imine, polyether Ether ketone, polyether fluorene, and a polymer obtained by polymerizing one or two or more kinds of polymerizable monomers having an ethylenically unsaturated group.

Can design and synthesize any resin particles with compressive properties suitable for conductive materials, and can easily control the hardness of resin particles to a better range, so the material of the resin particles is preferably one or two or more A polymer obtained by polymerizing a polymerizable monomer having a plurality of ethylenically unsaturated groups.

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

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; carboxyl groups 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, (meth) ) Alkyl (meth) acrylate compounds such as lauryl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, and isopropyl (meth) acrylate ; Oxygen atom (meth) acrylate compounds such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate; Nitrile-containing monomers such as (meth) acrylonitrile; vinyl acid compounds such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate; ethylene, propylene, isoprene, butadiene, etc. Unsaturated hydrocarbons; trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride, chlorostyrene and other halogens And the like.

Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, and tetramethylolmethane di (meth) acrylic acid. Ester, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) Acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) 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, phthalate di Allyl esters, diallyl allylamine, diallyl ether, γ- (meth) acryl methoxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. Silane monomer, etc.

The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of the method include a method of performing suspension polymerization in the presence of a radical polymerization initiator; and a method of using a non-crosslinked seed particle to swell the monomer together with the radical polymerization initiator to perform polymerization. .

In the case where the substrate particles are inorganic particles or organic-inorganic mixed particles other than metal particles, examples of the inorganic substance serving as the material of the substrate particles include silicon dioxide, alumina, barium titanate, zirconia, and Carbon black and so on. The inorganic substance is preferably not a metal. The particles formed from the above-mentioned silicon dioxide are not particularly limited, and examples thereof include hydrolysis of a silicon compound having two or more hydrolyzable alkoxysilyl groups to form cross-linked polymer particles, and optionally The particles obtained by firing. Examples of the organic-inorganic mixed particles include organic-inorganic mixed particles made of a crosslinked alkoxysilyl polymer and an acrylic resin.

The organic-inorganic mixed particles are preferably core-shell type organic-inorganic mixed particles having a core and a shell disposed on a surface of the core. The core is preferably an organic core. The shell is preferably an inorganic shell. From the viewpoint of more effectively reducing the connection resistance between the electrodes, the substrate particles are preferably organic-inorganic mixed particles having an organic core and an inorganic shell disposed 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 inorganic shell include inorganic substances listed as the material of the substrate particles. The material of the inorganic shell is preferably silicon dioxide. The inorganic shell is preferably formed by forming a metal alkoxide into a shell by a sol-gel method on the surface of the core, and then firing the shell. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of a silane oxide.

When the above-mentioned substrate particles are metal particles, examples of the metal to be a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, it is preferred that the substrate particles are not metal particles.

The particle diameter of the substrate particles is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 3 μm or more, and more preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 50 μm. the following. If the particle diameter of the substrate particles is greater than or equal to the above lower limit, the contact area between the conductive particles and the electrode becomes larger, so the conduction reliability between the electrodes becomes higher, and the distance between the electrodes connected via the conductive particles can be reduced more effectively. Its connection resistance. Furthermore, when a conductive part is formed on the surface of a base material particle, aggregation is not easy, and it is difficult to form aggregated conductive particles. When the particle diameter of the substrate particles is equal to or smaller than the upper limit described above, it is easy to sufficiently compress the conductive particles, and the connection resistance between electrodes connected via the conductive particles can be more effectively reduced.

The particle diameter of the substrate particles is particularly preferably 5 μm or more and 40 μm or less. If the particle diameter of the substrate particles is in the range of 5 μm or more and 40 μm or less, the interval between the electrodes can be further reduced, and even if the thickness of the conductive portion is increased, smaller conductive particles can be obtained.

Regarding the particle diameter of the substrate particles, when the substrate particles are truly spherical, they indicate diameters, and when the substrate particles are not truly spherical, they indicate maximum diameters.

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

The "Technovit 4000" manufactured by Kulzer was added so that the content of the conductive particles was 30% by weight, and dispersed to produce an embedded resin for conductive particle inspection. A cross-section of the conductive particles was cut using an ion polishing apparatus ("IM4000" manufactured by Hitachi High-Technologies Corporation) so as to be dispersed near the center of the conductive particles embedded in the inspection resin. 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 particles of each conductive particle were observed. The particle diameter of the substrate particles in each conductive particle was measured, and these were arithmetically averaged to be the particle diameter of the substrate particles.

(Conductive part) The method of forming a conductive part on the surface of the said base material particle, and the method of forming a solder part on the surface of the said base material particle or the said 2nd conductive part are not specifically limited. Examples of the method for forming the conductive portion and the solder portion include a method by electroless plating; a method by electroplating; a method by physical collision; a method by mechanochemical reaction; and a method by physical vaporization. A method of plating or physical adsorption; and a method of applying a metal powder, or a paste containing the metal powder and a binder, on the surface of the substrate particles, and the like. The method of forming the conductive portion and the solder portion is preferably a method by electroless plating, electroplating, or physical collision. Examples of the method using the physical vapor deposition include vacuum vapor deposition, ion plating, and ion sputtering. In addition, in the above-mentioned method by physical collision, for example, Theta Composer (manufactured by Tokusho Work Co., Ltd.) is used.

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

The conductive particles may have a solder layer in a single layer. The conductive particles may have a plurality of conductive portions (a solder portion and a second conductive portion). That is, in the above-mentioned conductive particles, two or more conductive portions may be laminated. In a case where the conductive portion is two or more layers, the conductive particles preferably have solder on an outer surface portion of the conductive portion.

The solder is preferably a metal (low melting point metal) having a melting point of 450 ° C or lower. The solder portion is preferably a metal layer (low melting point metal layer) having a melting point of 450 ° C or lower. The low melting point metal layer is a layer containing a low melting point metal. The solder in the conductive particles is preferably metal particles (low melting point metal particles) having a melting point of 450 ° C or lower. The low-melting metal particles are particles containing a low-melting metal. The low-melting-point metal means a metal having a melting point of 450 ° C or lower. The melting point of the low melting point metal is preferably 300 ° C or lower, and more preferably 160 ° C or lower. The solder in the conductive particles preferably contains tin. The content of tin in 100% by weight of the metal contained in the solder portion and 100% by weight of the metal contained in the solder in the conductive particle is preferably 30% by weight or more, more preferably 40% by weight or more It is more preferably 70% by weight or more, particularly preferably 90% by weight or more. When the content of tin contained in the solder in the solder portion and the conductive particles is greater than or equal to the above lower limit, the conduction reliability between the conductive particles and the electrode becomes higher.

Furthermore, the above-mentioned tin content can be measured by a high-frequency inductively coupled plasma emission spectrometer ("ICP-AES" manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer ("EDX-800HS", manufactured by Shimadzu Corporation) And so on.

By using the conductive particles having the above-mentioned solder on the outer surface portion of the conductive portion, the solder is melted and bonded to the electrodes, and the electrodes conduct electricity between the electrodes. For example, solder and electrodes are likely to make surface contact rather than point contact, and thus the connection resistance becomes low. In addition, by using conductive particles having solder on the outer surface portion of the conductive portion, the bonding strength between the solder and the electrode becomes higher, and as a result, the peeling of the solder from the electrode is less likely to occur, and the conduction reliability is effectively increased.

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

The material constituting the solder (solder portion) is preferably a filler material based on JIS Z3001: soldering term, and a liquidus of 450 ° C. or lower. Examples of the composition of the solder include metal compositions including zinc, gold, silver, lead, copper, tin, bismuth, and indium. Low-melting and lead-free tin-indium based (117 ° C eutectic) or tin-bismuth based (139 ° C eutectic) is preferred. That is, it is preferable that the said solder does not contain lead, The solder which contains tin and indium, or the solder which contains tin and bismuth is preferable.

In order to further improve the bonding strength between the solder and the electrode in the solder portion or the conductive particles, the solder in the conductive particles may further include nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, Cobalt, bismuth, manganese, chromium, molybdenum, palladium and other metals. From the viewpoint of further improving the bonding strength between the solder and the electrode in the solder portion or the conductive particles, the solder in the conductive particles preferably contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further improving the bonding strength between the solder and the electrode in the solder portion or the conductive particles, the content of these metals to increase the bonding strength is 100% by weight of the solder in the conductive particles, and preferably 0.0001. It is not less than 1% by weight 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 more than 160 ° C, more preferably more than 300 ° C, still more preferably more than 400 ° C, still more preferably more than 450 ° C, even more preferably more than 500 ° C, and most preferably more than 600 ° C. . Since the solder portion has a low melting point, it melts during conductive connection. The second conductive portion is preferably not melted during the conductive connection. The conductive particles are preferably used by melting a solder, preferably used by melting the solder portion, and preferably used by melting the solder portion without melting the second conductive portion. Since the melting point of the second conductive portion is higher than the melting point of the solder portion, the second conductive portion may not be melted during the conductive connection, and only the solder portion may be melted.

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

The second conductive portion preferably contains a 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. Also, as the metal, tin-doped indium oxide (ITO) may be used. These metals may be used alone or in combination of two or more.

The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer, a gold layer, or a copper layer, and even more preferably a copper layer. The conductive particle preferably has a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably has a nickel layer, a gold layer, or a copper layer, and further preferably has a copper layer. By using conductive particles having such preferable conductive portions for connection between electrodes, the connection resistance between the electrodes becomes lower. In addition, solder portions can be more easily formed on the surfaces of these preferred conductive portions.

The thickness of the solder portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, and more preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. When the thickness of the solder portion is greater than or equal to the above lower limit and less than or equal to the above upper limit, sufficient conductivity can be obtained, and the conductive particles will not become too hard, and the conductive particles will be sufficiently deformed during the connection between the electrodes.

The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 3 μm or more, and more preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 50 μm. Below, it is particularly preferably 40 μm or less. If the particle diameter of the conductive particles is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode, and the solder in the more conductive particles can be easily arranged between the electrodes, and the conduction can be achieved Reliability becomes higher.

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

The CV value of the particle diameter of the conductive particles is preferably 5% or more, more preferably 10% or more, and preferably 40% or less, and more preferably 30% or less. If the CV value of the particle diameter is greater than or equal to the above lower limit and less than or equal to the above upper limit, solder can be more efficiently disposed on the electrode. However, the CV value of the particle diameter of the conductive particles may not be higher than 5%.

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

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

The shape of the conductive particles is not particularly limited. The shape of the conductive particles may be a spherical shape or a shape other than a spherical shape such as a flat shape.

The content of the conductive particles in 100% by weight of the conductive material is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, particularly preferably 20% by weight or more, and most preferably It is 30% by weight or more, and preferably 95% by weight or less, more preferably 90% by weight or less, and still more preferably 85% by weight or less. The content of the conductive particles in 100% by weight of the conductive material may not exceed 80% by weight. If the content of the conductive particles is above the lower limit and below the upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode, and the solder in the more conductive particles can be easily arranged between the electrodes, and the conduction is reliable. Sex becomes higher. From the viewpoint of further improving the conduction reliability, it is preferable that the content of the conductive particles is large.

(Thermosetting compound) The conductive material of the present invention contains a thermosetting compound. The said thermosetting compound is a compound which can harden | cure by heating. Examples of the thermosetting compound include an oxetane compound, an epoxy compound, an episulfide compound, a (meth) acrylic compound, a phenol compound, an amine compound, an unsaturated polyester compound, and a polyurethane. Acid ester compounds, polysiloxane compounds, and polyimide compounds. From the viewpoint of making the conductive material harder and more viscous and further improving the conduction reliability, an epoxy compound or an episulfide compound is preferred, and an epoxy compound is more preferred. The conductive material preferably contains an epoxy compound. These thermosetting compounds may be used alone or in combination of two or more.

As said epoxy compound, aromatics, such as a resorcinol type epoxy compound, a naphthalene type epoxy compound, a biphenyl type epoxy compound, a benzophenone type epoxy compound, a phenol novolak type epoxy compound, etc. are preferable. Group of epoxy compounds. The melting temperature of the epoxy compound is preferably below the melting point of the solder. The melting temperature of the epoxy compound is preferably 100 ° C or lower, more preferably 80 ° C or lower, and even more preferably 40 ° C or lower. By using the above-mentioned preferred epoxy compound, the position of the first connection target member and the second connection target member can be suppressed when the viscosity is high at the stage of bonding the connection target member and the acceleration is imparted by the impact of transportation or the like. Offset. Furthermore, the heat at the time of hardening can drastically reduce the viscosity, and can efficiently aggregate the solder in the conductive particles.

In 100% by weight of the conductive material, the content of the thermosetting compound is preferably 5% by weight or more, more preferably 8% by weight or more, still more preferably 10% by weight or more, and preferably 60% by weight or less, It is more preferably 55% by weight or less, still more preferably 50% by weight or less, and even more preferably 40% by weight or less. If the content of the thermosetting compound is above the above lower limit and below the above upper limit, the solder in the conductive particles can be more efficiently arranged on the electrodes, further suppressing the positional shift between the electrodes, and further improving the conduction between the electrodes. reliability.

(Thermal hardener) It is preferable that the said conductive material contains a thermohardener. The conductive material preferably contains a thermosetting agent together with the thermosetting compound. The said thermosetting agent heat-hardens the said thermosetting compound. Examples of the thermal curing agent include an imidazole curing agent, a phenol curing agent, a thiol curing agent, an amine curing agent, an acid anhydride curing agent, a thermal cationic curing agent, and a thermal radical generator. These thermosetting agents may be used alone or in combination of two or more.

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

The imidazole curing agent is not particularly limited. Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-phenyl Imidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-tri and 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triisotricyanic acid adduct and the like.

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

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

The thermal cationic hardener is not particularly limited. Examples of the thermal cationic curing agent include a fluorene-based cationic curing agent, an oxon-based cationic curing agent, and a fluorene-based cationic curing agent. Examples of the fluorene-based cationic hardener include bis (4-thirdbutylphenyl) fluorene hexafluorophosphate and the like. Examples of the oxonium-based cation hardener include trimethyloxonium tetrafluoroborate and the like. Examples of the fluorene-based cationic hardener include tri-p-tolyl fluorene hexafluorophosphate and the like.

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

The reaction starting temperature of the above-mentioned thermosetting agent is preferably 50 ° C or higher, more preferably 60 ° C or higher, even more preferably 70 ° C or higher, and more preferably 250 ° C or lower, more preferably 200 ° C or lower, and even more preferably 190 ° C. It is below 180 ° C, particularly preferably below 180 ° C. If the reaction start temperature of the thermosetting agent is equal to or higher than the lower limit and equal to or lower than the upper limit, the solder is more efficiently disposed on the electrode.

The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, and more preferably 200 parts by weight or less, and more preferably 100 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. It is more preferably 75 parts by weight or less. When content of the said thermosetting agent is more than the said minimum, it will be easy to fully harden a thermosetting compound. If the content of the heat curing agent is equal to or less than the above upper limit, the remaining heat curing agent that does not participate in hardening does not easily remain after hardening, and the heat resistance of the cured product becomes higher.

(Flux) The conductive material of the present invention contains a flux. The conductive material of the present invention may preferably have a structure (a first structure) in which a flux having a particle diameter that is twice or more the average particle diameter of the above-mentioned flux does not exist. The conductive material of the present invention is preferably one that can be included in the total number of fluxes above 100%, and the flux having a particle size that is twice or more of the average particle diameter of the above fluxes is present in an amount less than 10% Constitution (1b constitution). The conductive material of the present invention preferably has a structure in which a composition obtained by removing the conductive particles from the conductive material is a colloid, and the flux is present in the form of colloid particles (second configuration).

In the case where the conductive material includes the first component 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 flux, and it is more preferable that the average particle diameter of the flux is not present. Flux with a particle size of 1.5 times or more. If the average particle diameter of the flux satisfies the above-mentioned preferable conditions, storage stability can be further improved, solder agglomeration can be further improved, and furthermore, the heat resistance of the hardened material can be further improved.

In the case where the conductive material has the above-mentioned 1b configuration, it is preferable that the flux having a particle size that is twice or more of the average particle diameter of the flux among the total number of the fluxes is 8% or less The number exists. More preferably, among 100% of the total number of the above-mentioned fluxes, fluxes having a particle size that is twice or more the average particle diameter of the above-mentioned fluxes are present in the number of 6% or less. If the ratio of the number of fluxes having a particle size that is more than two times the average particle diameter of the flux is less than the above upper limit, storage stability can be further improved, solder agglomeration can be further improved, and further, the solder can be further improved. Heat resistance of hardened material.

It is preferable that there is no flux having a particle diameter of 1.5 times or more of the average particle diameter of the above-mentioned flux, or of 100% of the total number of the above-mentioned fluxes, having an average particle size of 1.5 times or more of the above-mentioned flux. Fluxes with a particle size of less than 20% are present. It is preferable that among 100% of the total number of the above-mentioned fluxes, fluxes having a particle diameter of 1.5 times or more the average particle diameter of the above-mentioned fluxes are present in an amount of less than 20%. More preferably, among 100% of the total number of the above-mentioned fluxes, fluxes having a particle size of 1.5 times or more the average particle diameter of the above-mentioned fluxes are present at a number of 10% or less. Furthermore, it is preferable that the flux which has a particle diameter of 1.5 times or more of the average particle diameter of the said flux among the total number of said flux of 100% exists in the number of 5% or less. If the ratio of the number of fluxes having a particle diameter of 1.5 times or more the average particle diameter of the above-mentioned flux does not reach the above-mentioned upper limit and is less than the above-mentioned upper limit, the storage stability can be further improved, and the cohesiveness of solder can be further improved Furthermore, the heat resistance of a hardened | cured material can be improved further.

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

Regarding the particle diameter of the above-mentioned flux, when the flux is true spherical, it indicates the diameter, and when the flux is not true spherical, it indicates the maximum diameter.

The average particle diameter of the said flux represents a number average particle diameter. The particle diameter of the flux is preferably determined 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 fluxes from the viewpoint of more effectively improving storage stability, the viewpoint of more effectively improving the solder agglomeration, and the viewpoint of more effectively improving the heat resistance of the hardened material. It is preferably at most 40%, more preferably at most 20%. The lower limit of the CV value of the particle size of the flux is not particularly limited. The CV value of the particle size of the flux can be 0.01% or more.

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

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

The shape of the flux is not particularly limited. The shape of the flux may be a spherical shape or a shape other than a spherical shape such as a flat shape.

When the said conductive material has the said 2nd structure, the composition after removing the said conductive particle from the said conductive material is a colloid. From the viewpoint of more effectively improving the storage stability, the viewpoint of more effectively improving the cohesiveness of the solder, and the viewpoint of more effectively improving the heat resistance of the hardened material, the composition is preferably a colloid as a whole. The above composition may include a part that is a colloid, and the entire composition may not be a colloid.

When the said conductive material has the said 2nd structure, the said flux exists as a colloid particle. From the viewpoint of more effectively improving the storage stability, the viewpoint of more effectively improving the cohesiveness of the solder, and the viewpoint of more effectively improving the heat resistance of the hardened material, the above-mentioned flux is preferably colloid particles, and the above-mentioned flux Colloidal particles having the above-mentioned average particle diameter in the composition are preferred. The above-mentioned flux is preferably dispersed in the above-mentioned composition from the viewpoint of more effectively improving the storage stability, the viewpoint of more effectively improving the cohesiveness of the solder, and the viewpoint of more effectively improving the heat resistance of the cured product, The flux is more preferably uniformly dispersed in the composition. In the above-mentioned conductive material, it is preferable that more than 20% of the total number of fluxes are colloidal particles. In the above-mentioned conductive material, as long as a part of the flux is colloidal particles, not all the fluxes may be colloidal particles.

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

Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, and an organic acid. And pine resin. These fluxes may be used alone or in combination of two or more.

Examples of the molten salt include ammonium chloride. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid, malic acid, and glutaric acid. Examples of the turpentine include activated turpentine and non-activated turpentine. The above-mentioned flux is preferably an organic acid or rosin having two or more carboxyl groups. 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 rosin is a rosin containing abietic acid as a main component. The above-mentioned flux is preferably rosin, and more preferably rosin acid. By using the better flux, the conduction reliability between the electrodes becomes higher.

The melting point (active temperature) of the above-mentioned flux is preferably 50 ° C or higher, more preferably 70 ° C or higher, even more preferably 80 ° C or higher, and more preferably 200 ° C or lower, more preferably 190 ° C or lower, even more preferably 160 ° C or lower, more preferably 150 ° C or lower, even more preferably 140 ° C or lower. When the melting point (active temperature) of the flux is above the lower limit and below the upper limit, the flux effect is more effectively exhibited, and the solder in the conductive particles is more efficiently disposed on the electrode. The melting point (active temperature) of the flux is preferably 60 ° C or higher and 190 ° C or lower. The melting point (active temperature) of the above-mentioned flux is particularly preferably 80 ° C or higher and 140 ° C or lower.

Examples of the flux whose activity temperature (melting point) of the flux is 60 ° C or higher and 190 ° C or lower include succinic acid (melting point 186 ° C), glutaric acid (melting point 96 ° C), and adipic acid (melting point 152 ° C). ), Dicarboxylic acids such as pimelic acid (melting point: 104 ° C), suberic acid (melting point: 142 ° C), benzoic acid (melting point: 122 ° C), and malic acid (melting point: 130 ° C).

The boiling point of the flux is preferably 200 ° C or lower.

The above-mentioned flux is preferably a flux that releases cations by heating. By using a flux that releases cations by heating, the solder in the conductive particles can be more efficiently disposed on the electrode.

Examples of the flux that releases cations by heating include the above-mentioned thermal cation hardeners.

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

From the viewpoint of efficiently disposing the solder in the conductive particles on the electrode, 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 higher, and more preferably It is preferably lower than 10 ° C. However, the melting point of the flux may be higher than the melting point of the solder in the conductive particles. Generally, the use temperature of the conductive material is above the melting point of the solder in the conductive particles. If the melting point of the flux is below the use temperature of the conductive material, the melting point of the flux is higher than that of the conductive particles. The melting point of the solder, the above-mentioned flux can also fully exert its performance as a flux. For example, the conductive material is used at a temperature of 150 ° C or higher, and contains conductive solder (Sn ₄₂ Bi ₅₈ : melting point 139 ° C) and conductive 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, fully exhibits a flux effect.

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

The 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, and aliphatic carboxylic acids. Malic acid; Cyclohexylcarboxylic acid, 1,4-cyclohexyldicarboxylic acid as cyclic aliphatic carboxylic acid; Phthalic acid, terephthalic acid, trimellitic acid and ethylenediamine as aromatic carboxylic acids Tetraacetic acid and so on. The acid compound is preferably glutaric acid, azelaic acid, or malic acid.

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

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

The flux which satisfies the 1a structure, the 1b structure, and the 2nd structure can be obtained, for example, by melting a solid flux and then reprecipitating it. Preferably, the reprecipitation is performed smoothly. The method of obtaining the above-mentioned flux is preferably a method of heating the solid flux above the melting point and completely melting the flux. The method for obtaining the above-mentioned flux is preferably a method for slowly re-precipitating the molten flux. By the above method, a uniform flux having the above-mentioned average particle diameter can be easily obtained.

As another method for obtaining a flux having a relatively small average particle diameter, for example, a method of pulverizing a solid flux may be mentioned. However, in a method of pulverizing a 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 the fluxes are pulverized, the fluxes are aggregated with each other, and the fluxes tend to be uneven. Uneven flux (pulverized flux) is difficult to uniformly disperse in the conductive material. When uneven flux is used, the content of the flux in the conductive material is likely to be relatively high in order to improve the cohesiveness of the solder. More. As a result, the storage stability of the conductive material is reduced, and the heat resistance of the hardened material of the conductive material is reduced, and it is difficult to obtain the effect of the present invention. Therefore, the above-mentioned flux is preferably obtained by a method other than the method of pulverizing the solid flux, and is preferably obtained by melting the solid flux having a relatively slow re-precipitation rate and then re-precipitating it.

From the viewpoint of more effectively improving storage stability, more effectively improving the cohesiveness of the solder, and more effectively improving the heat resistance of the hardened material, the content of the above-mentioned flux relative to 100 parts by weight of the above-mentioned thermosetting compound is The content is preferably 1 part by weight or more, more preferably 2 parts by weight or more, and preferably 20 parts by weight or less, and more preferably 15 parts by weight or less.

From the viewpoint of more effectively improving the storage stability, the viewpoint of more effectively improving the cohesiveness of the solder, and the viewpoint of more effectively improving the heat resistance of the hardened material, among the above-mentioned conductive materials, the flux The content is preferably 0.05% by weight or more, more preferably 2% by weight or more, and preferably 20% by weight or less, and more preferably 15% by weight or less. In addition, if the content of the flux is above the lower limit and below the 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 the solder formed in the conductive particles can be more effectively removed. And the oxide film on the surface of the electrode.

(Filler) A filler may be added to the conductive material. The filler may be an organic filler or an inorganic filler. By adding a filler, conductive particles can be uniformly aggregated on all electrodes of the substrate.

It is preferable that the said conductive material does not contain the said filler, or contains the said filler in 5 weight% or less. When a crystalline thermosetting compound is used, the smaller the content of the filler, the easier it is for the solder to move to the electrode.

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

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

(Connection Structure) The connection structure of the present invention includes: a first connection target member having a first electrode on the surface; a second connection target member having a second electrode on the surface; and a connection portion which is The first connection target member is connected to the second connection target member. In the connection structure of the present invention, a material of the connection portion is the conductive material. In the connection structure of the present invention, the connection portion is a hardened product of the conductive material. In the connection structure of the present invention, the connection portion is formed of the conductive material. In the connection structure of the present invention, the first electrode and the second electrode are electrically connected through a solder portion of the connection portion.

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 disposed on the electrode (wire). Moreover, it is difficult to dispose a part of the solder in a region (gap) where no electrode is formed, and the amount of solder disposed in a region where the electrode is not formed can be made relatively small. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, it can prevent the electrical connection between the laterally adjacent electrodes that should not be connected, and can improve the insulation reliability.

In addition, in order to efficiently dispose the solder in the conductive particles on the electrode, and to make the amount of solder disposed in the region where the electrode is not formed relatively small, it is preferable that the conductive material uses a conductive paste instead of a conductive film.

The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, and preferably 100 μm or less, and more preferably 80 μm or less. The solder wetting area on the surface of the electrode (the area of the solder contact in 100% of the area of the exposed electrode) is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, and 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 includes a first connection target member 2, a second connection target member 3, and a connection portion 4 that connects the first connection target member 2 and the second connection target member 3. The connection portion 4 is formed of the aforementioned conductive material. In this embodiment, the conductive material includes conductive particles, a thermosetting compound, and a flux. In this embodiment, solder particles are included as the conductive particles. The said thermosetting compound, the said thermosetting agent, and the said flux are called a thermosetting component.

The connecting portion 4 includes a solder portion 4A formed by a plurality of solder particles being aggregated and bonded to each other, and a hardened portion 4B formed by thermally curing a thermosetting component.

The first connection target member 2 has a plurality of first electrodes 2a on its surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on its surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected through the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. Furthermore, solder is not present in the connection portion 4 in a region (a portion of the hardened portion 4B) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a. In a region different from the solder portion 4A (the portion of the hardened portion 4B), there is no solder separated from the solder portion 4A. Moreover, if it is a small amount, solder may exist in the area | region (hardened | cured material 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 collected between the first electrode 2 a and the second electrode 3 a. After the plurality of solder particles are melted, the molten material of the solder particles wets and diffuses on the surface of the electrode. Post-curing to form the solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 3a become larger. That is, by using solder particles, the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode are compared with a case where conductive particles of a metal such as nickel, gold, or copper are used on the outer surface of the conductive portion. The contact area of 3a becomes larger. Therefore, the connection reliability and connection reliability in the connection structure 1 are increased. Furthermore, the flux contained in the conductive material is generally gradually deactivated by heating.

Furthermore, in the connection structure 1 shown in FIG. 1, all the solder portions 4A are located in a region facing between the first and second electrodes 2 a and 3 a. The connection structure 1X of the modified example shown in FIG. 3 is different from the connection structure 1 shown in FIG. 1 only in the connection portion 4X. The connection portion 4X includes a solder portion 4XA and a hardened portion 4XB. Like the connection structure 1X, most of the solder portion 4XA is located in a region facing the first and second electrodes 2a and 3a, and a part of the solder portion 4XA is directed from a region 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 and 3a oppose is a portion of the solder portion 4XA, and is not solder separated from the solder portion 4XA. Furthermore, in this embodiment, the amount of solder separated from the solder portion can be reduced, but there may be solder separated from the solder portion in the hardened portion.

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

A portion where the first electrode and the second electrode face each other is viewed in a direction in which the first electrode, the connection portion, and the second electrode are stacked. In this case, from the viewpoint of further improving the conduction reliability, it is preferably 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. (More preferably, it is 70% or more, particularly preferably 80% or more, and most preferably 90% or more) The solder portion of the connection portion is disposed.

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

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

A conductive material 11 is disposed on a surface of the first connection target member 2 on which the first electrode 2a is provided. After the conductive material 11 is disposed, the solder particles 11A are disposed on the first electrode 2a (line) and on the area (gap) where the first electrode 2a is not formed.

The arrangement method of 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 second connection target member 3 having the second electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2 (b), the second conductive material 11 on the surface of the first connection target member 2 is disposed on the surface of the conductive material 11 on the side opposite to the first connection target member 2 side. Connection target member 3 (second step). On the surface of the conductive material 11, a second connection target member 3 is arranged from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

Next, the conductive material 11 is heated above the melting point of the solder particles 11A (third step). The conductive material 11 is preferably heated to a temperature higher than the curing temperature of the thermosetting component 11B (thermosetting compound). During this heating, the solder particles 11A existing in the area where the electrode is not formed are collected between the first electrode 2a and the second electrode 3a (self-aggregation effect). When a conductive paste is used instead of a conductive film, the solder particles 11A are more effectively collected between the first electrode 2a and the second electrode 3a. The solder particles 11A are fused and bonded to each other. The thermosetting component 11B is thermoset. As a result, as shown in FIG. 2 (c), the connection portion 4 that connects the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connecting portion 4 is formed of the conductive material 11, a plurality of solder particles 11A are joined to form a solder portion 4A, and a thermosetting component 11B is thermally cured to form a hardened portion 4B. If the solder particles 11A move sufficiently, the solder particles 11A may be completed between the first electrode 2a and the second electrode 3a from the beginning of the movement of the solder particles 11A not located between the first electrode 2a and the second electrode 3a. Do not keep the temperature constant until it moves.

In this embodiment, it is preferable that no pressure is applied in the second step and the third step. In this case, the weight of the second connection target member 3 is applied to the conductive material 11. Therefore, when the connection portion 4 is formed, the solder particles 11A are more effectively collected between the first electrode 2a and the second electrode 3a. Furthermore, if pressure is applied in at least one of the second step and the third step described above, the tendency of the solder particles 11A to be prevented from accumulating between the first electrode 2a and the second electrode 3a is increased.

When the second connection target member is superimposed on the first connection target member coated with the conductive material, the first connection target member and the second connection target member are misaligned, and the first connection target member is overlapped. Cases of 1 connection target member and second connection target member. In this embodiment, the pressure is not applied, so the offset can be corrected to connect the electrode of the first connection target member and the electrode of the second connection target member (self-aligned effect). The reason for this is that the molten solder self-agglutinated between the electrode of the first connection target member and the electrode of the second connection target member is the solder and conduction between the electrode of the first connection target member and the electrode of the second connection target member. When the contact area of other components of the material is minimized, the energy becomes stable. Further, the reason is that the force applied to the connection structure which is the alignment of the connection structure which becomes the smallest area works. At this time, it is preferable that the conductive material is not hardened, and the viscosity of 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 50 Pa · s or less, more preferably 10 Pa · s or less, even more preferably 1 Pa · s or less, and more preferably 0.1 Pa · s or more, more preferably 0.2 Pa · s or more. When the said viscosity is below the said upper limit, the solder in electroconductive particle can be efficiently aggregated. If the viscosity is greater than or equal to the above lower limit, the pores of the connection portion can be suppressed, and the overflow of the conductive material to the outside of the connection portion can be suppressed.

The viscosity of the conductive material at the melting point of the solder is measured as follows.

The viscosity of the conductive material at the melting point of the solder can be STRESSTECH (manufactured by REOLOGICA). The strain control is 1 rad, the frequency is 1 Hz, the temperature rise rate is 20 ° C / min, and the measurement temperature range is 25 to 200 ° C. When the melting point exceeds 200 ° C, the measurement is performed under the condition that the upper temperature limit is the melting point of the solder. Based on the measurement results, the viscosity at the melting point (° C) of the solder was evaluated.

In this way, the connection structure 1 shown in FIG. 1 is obtained. The second step and the third step may be performed continuously. Moreover, after performing the said 2nd step, the laminated body of the 1st connection target member 2, the conductive material 11, and the 2nd connection target member 3 obtained may be moved to a heating part, and the said 3rd step may be performed. In order to perform the above-mentioned heating, the above-mentioned laminated body may be arranged on the heating member, or the above-mentioned laminated body may be arranged in the heated space.

The heating temperature in the third step is preferably 140 ° C or higher, more preferably 160 ° C or higher, and more preferably 450 ° C or lower, more preferably 250 ° C or lower, and even more preferably 200 ° C or lower.

Examples of the heating method in the third step include heating the entire connection structure to a melting point of the solder in the conductive particles and a curing temperature of the thermosetting component or more using a reflow furnace or an oven; or only The connection portion of the connection structure is locally heated.

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

In addition, when the heating is performed locally by the heating plate, it is preferable that the surface of the heating plate is formed by a metal having high thermal conductivity right below the connection portion, and the other portion is preferably thermally conductive by fluororesin or the like that is not heated. The lower material forms the upper surface of the heating plate.

The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include electronic components such as semiconductor wafers, semiconductor packages, LED chips, LED packages, capacitors, and diodes; resin films, printed boards, and flexible printing. Electronic components such as circuit boards such as substrates, flexible flat cables, rigid flexible substrates, glass epoxy substrates, and glass substrates. The first and second connection target members are preferably electronic components.

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 circuit boards, flexible flat cables, and rigid flexible substrates are highly flexible and relatively lightweight. When a conductive film is used for the connection of such a connection target member, solder tends to be hard to collect on an electrode. In contrast, by using a conductive paste, even if a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, the solder can be efficiently collected on the electrodes, thereby fully improving the reliability of conduction between the electrodes Sex. When a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, compared with the case where other connection target members such as a semiconductor wafer are used, it is more effective to obtain the electrode-to-electrode interval caused by not applying pressure. Improved reliability of continuity.

Examples of the electrode provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the connection target member is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. When the above-mentioned electrode is an aluminum electrode, it may be an electrode formed of only aluminum or an electrode having an aluminum layer on the surface area of the metal oxide layer. Examples of the material of the metal oxide layer include: indium oxide doped with a trivalent metal element; and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

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

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

Thermal hardener (thermo-hardening accelerator (catalyst)): "BF3-MEA" manufactured by Stella Chemifa, boron trifluoride-monoethylamine complex

Conductive particles: "Sn ₄₂ Bi ₅₈ (DS-10)" manufactured by Mitsui Metals Mining Corporation

Flux: (1) Flux 1 Production method of Flux 1: Put 24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) in a glass bottle, and make the solution at room temperature. Wait for dissolution until it becomes 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 mixed solution. The obtained mixed solution was put in a refrigerator at 5-10 ° C and left overnight. The precipitated crystal was separated by filtration, washed with water, and vacuum-dried. The dried crystal was heated at 140 ° C for 15 minutes to completely melt it, and slowly re-precipitated at 25 ° C for 30 minutes, thereby obtaining a flux 1.

(2) Flux 2 Production method of flux 2: Put 24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) in a glass bottle, and dissolve these at room temperature until Become uniform. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. The obtained mixed solution was put in a refrigerator at 5-10 ° C and left overnight. The precipitated crystal was separated by filtration, washed with water, and vacuum-dried. The dried crystal was heated at 160 ° C. for 5 minutes to completely melt it, and slowly re-precipitated at 25 ° C. for 30 minutes, thereby obtaining a flux 2.

(3) Flux 3 Preparation method of flux 3: Put 24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) in a glass bottle, and dissolve these at room temperature until Become uniform. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. The obtained mixed solution was put in a refrigerator at 5-10 ° C and left overnight. The precipitated crystal was separated by filtration, washed with water, and vacuum-dried. The dried crystals were pulverized by a mortar, thereby obtaining a flux 3.

(4) Flux 4 Production method of flux 4: Put 24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) in a glass bottle, and dissolve these at room temperature until Become uniform. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. The obtained mixed solution was put in a refrigerator at 5-10 ° C and left overnight. The precipitated crystal was separated by filtration, washed with water, and vacuum-dried. The dried crystals were pulverized by a jet mill pulverizer manufactured by Nisshin Engineering, thereby obtaining a flux 4.

(Examples 1 to 2 and Comparative Examples 1 to 3) (1) Production of conductive material (anisotropic conductive paste) The components shown in Table 1 below were blended at the compounding amounts shown in Table 1 below to obtain a 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 the production, the first connection structure was produced as follows.

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

The overlapping area of the glass epoxy substrate and the 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 glass epoxy substrate, a conductive material (anisotropic conductive) immediately after fabrication was applied by screen printing using a metal mask so as to have a thickness of 100 μm on the glass epoxy substrate. Paste) to form a conductive material (anisotropic conductive paste) layer. Next, the flexible printed circuit board is laminated on the surface of the conductive material (anisotropic conductive paste) layer such that the electrodes face each other. At this time, no pressure is applied. The weight of the above-mentioned flexible printed substrate is applied to a 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 the solder) after 5 seconds from the start of the temperature rise. Furthermore, after 15 seconds from the start of the temperature rise, the temperature of the conductive material (anisotropic conductive paste) layer was heated to 160 ° C., and the conductive material (anisotropic conductive paste) layer was hardened to obtain a connection structure. During heating, no pressure is applied.

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

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

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

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

(Evaluation) (1) Existing state of flux Using a laser microscope ("OLS4100" manufactured by Olympus), the particle diameters of 50 arbitrary fluxes were measured, and the average particle diameter of the obtained flux was calculated based on the average value. .

Based on the average particle size of the obtained flux, calculate the ratio of the number of fluxes with a particle size that is 2 times or more the average particle size of the flux in the total number of fluxes, and the total number of fluxes. The ratio of the number of fluxes having a particle diameter of 1.5 times or more the average particle diameter of the flux in the number of 100%.

(2) Colloid By filtering the obtained conductive material (anisotropic conductive paste), conductive particles are removed from the conductive material (anisotropic conductive paste). The composition after removing the conductive particles was put into a 10 mL spiral tube, and a laser stylus was irradiated from the lateral direction of the spiral tube, thereby confirming whether a tinter phenomenon caused by a flux was observed. The colloid was determined according to the following criteria. Furthermore, it was confirmed that the thermosetting compound and the thermosetting agent were dissolved.

[Criterion Criteria] ○: Tinted ear phenomenon caused by flux was observed ×: Tinted ear phenomenon caused by flux was not observed

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

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

(4) Heat resistance of hardened material The obtained conductive material (anisotropic conductive paste) was heated at 150 ° C for 2 hours, thereby obtaining a hardened material. The glass transition temperature (Tg) of the obtained hardened | cured material was measured using the dynamic viscoelasticity measuring device ("Rheogel-E" made by UBM company) under the conditions of a temperature increase rate of 10 degree-C / min. The heat resistance of the cured product was determined according to the following criteria.

[Criterion for determining heat resistance of hardened material] ○: Tg of hardened material is 100 ° C or more △: Tg of hardened material is 90 ° C or more and less than 100 ° C ×: Tg of hardened material is less than 90 ° C

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

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

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

[Judgment Criteria for Continuity Reliability] ○ ○: The average value of the connection resistance is 50 mΩ or less ○: The average value of the connection resistance exceeds 50 mΩ and 70 mΩ or less △: The average value of the connection resistance exceeds 70 mΩ and 100 mΩ or less ×: The average connection resistance exceeds 100 mΩ, or connection failure occurs

(7) Insulation reliability between transversely adjacent electrodes In the obtained first, second, and third connection structures (n = 15), after being left for 100 hours in an environment of 85 ° C and 85% humidity, 5 V was applied between the laterally adjacent electrodes, and the resistance was measured at 25 places. The insulation reliability was judged according to the following criteria.

[Judgment Criteria for Insulation Reliability] ○ ○: The average value of connection resistance is 10 ⁷ Ω or more ○: The average value of connection resistance is 10 ⁶ Ω or more and less than 10 ⁷ Ω △: The average value of connection resistance is 10 ⁵ Ω Above and below 10 ⁶ Ω ×: The average value of connection resistance is below 10 ⁵ Ω

The results are shown in Table 1 below.

[Table 1]

Even when it is convenient to use a resin film, a flexible flat cable, and a rigid flexible substrate instead of a flexible printed substrate, the same tendency can be seen.

1‧‧‧ connect structure

1X‧‧‧ Connected Structure

2‧‧‧The first connection target component

2a‧‧‧The first electrode

3‧‧‧ 2nd connection target component

3a‧‧‧Second electrode

4‧‧‧ Connection Department

4X‧‧‧Connecting section

4A‧‧‧Solder Department

4XA‧‧‧Solder Department

4B‧‧‧Hardened Materials Division

4XB‧‧‧Hardened material department

11‧‧‧ conductive material

11A‧‧‧Solder particles (conductive particles)

11B‧‧‧thermosetting ingredients

21‧‧‧ conductive particles (solder particles)

31‧‧‧ conductive particles

32‧‧‧ substrate particles

33‧‧‧Conductive part (conductive part with solder)

33A‧‧‧The second conductive part

33B‧‧‧Solder Department

41‧‧‧ conductive particles

42‧‧‧Solder Department

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 for 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 for a conductive material. FIG. 5 is a cross-sectional view showing a second example of conductive particles that can be used for a conductive material. Fig. 6 is a cross-sectional view showing a third example of conductive particles that can be used for a conductive material.

Claims (8)

A conductive material comprising a plurality of conductive particles, a thermosetting compound, and a flux having solder on an outer surface portion of a conductive portion, and having at least one of the following first and second configurations: First Composition: There is no flux having a particle size that is more than two times the average particle diameter of the above-mentioned flux, or that 100% of the total number of the above fluxes has a particle that is more than two times the average particle diameter of the above-mentioned flux The flux with a diameter of less than 10% exists; the second composition: the composition after removing the conductive particles from the conductive material is a colloid, and the flux exists in the form of colloid particles. For example, the conductive material of claim 1 does not include a flux having a particle diameter of 1.5 times or more the average particle diameter of the above-mentioned flux, or an average particle of the above-mentioned flux among 100% of the total number of the above-mentioned flux. Fluxes with a particle diameter of 1.5 times or more exist in a number of less than 20%. For the conductive material of claim 1 or 2, wherein the average particle diameter of the above-mentioned 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 or more and 20 parts by weight or less based on 100 parts by weight of the thermosetting compound. For example, the conductive material of claim 1 or 2, wherein the content of the above-mentioned flux in the conductive material 100% by weight is 0.05% by weight or more and 20% by weight or less. If the conductive material of claim 1 or 2 is a conductive paste. A connection structure including: a first connection target member having a first electrode on a surface; a second connection target member having a second electrode on a surface; and a connection portion which connects the first connection target The component is connected to the second connection target component; and the material of the connection portion is the conductive material as in any one of claims 1 to 6, and the first electrode and the second electrode are electrically connected by the solder portion of the connection portion. Sexual connection. For example, the connection structure of claim 7, wherein when a portion where the first electrode and the second electrode face each other is viewed in a lamination direction of the first electrode, the connection portion, and the second electrode, the first electrode The solder portion of the connection portion is disposed in at least 50% of an area where 100% of the electrode and the second electrode face each other.