KR102618237B1 - Conductive materials and connection structures - Google Patents

Abstract

A conductive material capable of exhibiting high conduction reliability is provided in that it has high storage stability and exhibits excellent solder cohesion even when left for a long time after the conductive material is disposed on the member to be connected. The electrically conductive material according to the present invention includes a plurality of conductive particles having solder on the outer surface portion of the electrically conductive portion, a thermosetting component, and a flux. The flux is a salt of an acid and a base, and among the electrically conductive materials at 25°C, the above The flux exists as a solid.

Description

Conductive materials and connection structures

The present invention relates to a conductive material containing conductive particles containing solder. Furthermore, the present invention relates to a bonded structure using the above-described electrically conductive material.

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

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

When, for example, an electrode of a flexible printed circuit board and an electrode of a glass epoxy substrate are electrically connected by the anisotropic conductive material, the anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. Next, flexible printed boards are laminated, heated and pressed. Thereby, the anisotropic electrically-conductive material is hardened, the electrodes are electrically connected via electroconductive particles, and a connected structure is obtained.

As an example of the anisotropic conductive material, Patent Document 1 below describes an anisotropic conductive material containing conductive particles and a resin component whose curing has not been completed at the melting point of the conductive particles. Specifically, the conductive particles include tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), and gallium ( Metals such as Ga) and thallium (Tl) and alloys of these metals are exemplified.

In Patent Document 1, a resin heating step of heating the anisotropic conductive resin to a temperature that is higher than the melting point of the conductive particles and at which curing of the resin component is not completed, and a resin component curing step of curing the resin component, Electrical connection between electrodes is described. Additionally, Patent Document 1 describes mounting under the temperature profile shown in FIG. 8 of Patent Document 1. In Patent Document 1, the conductive particles melt within the resin component where curing has not been completed at the temperature at which the anisotropic conductive resin is heated.

Patent Document 2 below discloses an adhesive tape that includes a resin layer containing a thermosetting resin, solder powder, and a curing agent, and the solder powder and the curing agent are present in the resin layer. This adhesive tape is in the form of a film and not a paste.

Patent Document 3 below discloses a thermosetting resin composition containing solder particles, a thermosetting resin binder, and a flux component. In Patent Document 3, the flux components include (1) a salt of dicarboxylic acid or tricarboxylic acid and diethanolamines or triethanolamines, and (2) addition of a carboxylic acid anhydride and diethanolamines or triethanolamines. Reactants are illustrated.

Japanese Patent Publication No. 2004-260131 WO2008/023452A1 Japanese Patent Publication No. 2013-256584

Conventional solder powders and anisotropic electrically conductive pastes containing conductive particles having a solder layer on the surface may have low storage stability. Additionally, with conventional anisotropic conductive pastes, when the conductive material is disposed on the connection target member during connection between electrodes and then left for a long time, it may become difficult for the solder to aggregate on the electrodes. As a result, conduction reliability is likely to decrease.

The purpose of the present invention is to provide a conductive material capable of exhibiting high conduction reliability because it has high storage stability and exhibits excellent solder cohesion even when left for a long time after the conductive material is disposed on the member to be connected. Furthermore, an object of the present invention is to provide a bonded structure using the above-described electrically conductive material.

According to a broad aspect of the present invention, the flux includes a plurality of conductive particles having solder on the outer surface portion of the conductive portion, a thermosetting component, and a flux, the flux is a salt of an acid and a base, and the flux is selected from among conductive materials at 25°C. A conductive material is provided that exists as a solid at 25°C.

In a certain aspect of the electrically conductive material according to the present invention, the flux alone is solid at 25°C when not mixed with the electrically conductive particles and the thermosetting component.

In a specific aspect of the conductive material according to the present invention, the flux is a salt of an organic compound having a carboxyl group and an organic compound having an amino group.

In a specific aspect of the conductive material according to the present invention, the average particle diameter of the flux is 30 μm or less in the conductive material at 25°C.

In a specific aspect of the electrically conductive material according to the present invention, in the electrically conductive material at 25°C, the ratio of the average particle diameter of the flux to the average particle diameter of the electrically conductive particles is 3 or less.

In a specific aspect of the electrically conductive material according to the present invention, the melting point of the flux is -50°C or higher than the melting point of the solder in the conductive particles and is equal to or lower than the melting point of the solder in the conductive particles +50°C.

In a specific aspect of the electrically conductive material according to the present invention, the electrically conductive particles are solder particles.

In a specific aspect of the electrically-conductive material according to the present invention, the thermosetting component contains a thermosetting compound having a triazine skeleton.

In a certain situation of the electrically-conductive material which concerns on this invention, the said flux adheres on the surface of the said electroconductive particle.

In a certain situation of the electrically-conductive material which concerns on this invention, the average particle diameter of the said electroconductive particle is 1 micrometer or more and 40 micrometers or less.

In a certain situation of the electrically-conductive material which concerns on this invention, content of the said electroconductive particle is 10 weight% or more and 90 weight% or less in 100 weight% of the said electrically-conductive materials.

In a specific aspect of the electrically conductive material according to the present invention, the electrically conductive material is an electrically conductive paste.

According to a broad aspect of the present invention, there is provided a first connection target member having at least one first electrode on its surface, a second connection target member having at least one second electrode on its surface, the first connection target member, and the above A connection comprising a connection part connecting a second connection target member, wherein the material of the connection part is the above-described conductive material, and the first electrode and the second electrode are electrically connected by a solder portion in the connection part. A structure is provided.

In a specific aspect of the connection structure according to the present invention, when the portions of the first electrode and the second electrode facing each other are viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode A solder portion in the connection portion is disposed in more than 50% of 100% of the area of the opposing portion of the second electrode.

The conductive material according to the present invention includes a plurality of conductive particles having solder on the outer surface portion of the conductive portion, a thermosetting component, and a flux. The flux is a salt of an acid and a base, and among the conductive materials at 25°C, Since the flux exists in a solid state, the storage stability of the conductive material can be improved, and after the conductive material is placed on the member to be connected, it exhibits excellent solder cohesion even if left for a long time, thereby demonstrating high conduction reliability. .

1 is a cross-sectional view schematically showing a bonded structure obtained using a conductive material according to an embodiment of the present invention.
2(a) to 2(c) are cross-sectional views for illustrating an example of each step of a method of manufacturing a bonded 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 bonded structure.
FIG. 4 is a cross-sectional view showing a first example of conductive particles that can be used in an electrically conductive material.
FIG. 5 is a cross-sectional view showing a second example of conductive particles that can be used in an electrically conductive material.
Fig. 6 is a cross-sectional view showing a third example of conductive particles that can be used in electrically conductive materials.

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

(Challenge Materials)

The electrically conductive material according to the present invention contains a plurality of conductive particles and a binder. The said electroconductive particle has an electroconductive part. The electrically conductive particles have solder on the outer surface of the electrically conductive portion. Solder is included in the conductive portion and is part or all of the conductive portion. The binder is a component excluding the conductive particles contained in the conductive material.

The electrically conductive material according to the present invention contains a thermosetting component and a flux as the binder. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent.

In the electrically conductive material according to the present invention, the flux is a salt of an acid and a base. In addition, in the electrically conductive material according to the present invention, the flux exists as a solid in the electrically conductive material at 25°C. More specifically, in the electrically conductive material according to the present invention, the flux exists as a solid at 25°C in the electrically conductive material at 25°C.

Additionally, whether the flux is solid in a conductive material at 25°C can be determined as follows. In this specification, regarding flux that is not a liquid at 25°C, a flux that maintains its shape when the conductive material containing the flux is left standing for 5 minutes at 25°C is defined as a solid flux at 25°C. A flux that does not maintain its shape when the conductive material containing the flux is left standing for 5 minutes is defined as a semi-solid flux at 25°C. Additionally, the flux of semi-solids at 25°C is not included in the flux of solids at 25°C.

In the present invention, since the above-described structure is provided, the storage stability of the conductive material can be improved. Furthermore, in the present invention, since the above-mentioned configuration is provided, excellent solder cohesion is exhibited even if left for a long time after the conductive material is disposed on the member to be connected, and thus high conduction reliability can be achieved.

In the present invention, it is preferable that the flux alone is solid at 25°C when not mixed with the conductive particles and the thermosetting component. It is preferable that the flux alone before being mixed with the conductive particles and the thermosetting component is solid at 25°C. In these cases, it is easy to make the flux exist as a solid in a conductive material at 25°C.

Additionally, whether the flux alone is solid at 25°C can be judged as follows. In this specification, regarding flux that is not a liquid at 25°C, flux that maintains its shape when the flux alone is left for 5 minutes at 25°C is defined as a solid flux at 25°C, and the flux alone at 25°C is defined as 5 minutes. A flux that does not maintain its shape when left to stand for a minute is defined as a semi-solid flux at 25°C. Additionally, the flux of semi-solids at 25°C is not included in the flux of solids at 25°C.

When obtaining the connection structure, after disposing the conductive material on the first connection target member, the laminate of the first connection target member and the conductive material is temporarily stored before disposing the second connection target member on the conductive material. There are cases. In the present invention, a connection structure with excellent conduction reliability can be obtained even if the laminate is stored.

Furthermore, in the present invention, since the above-described structure is provided, the solder in the conductive particles can be efficiently disposed on the electrode even if the electrode width is narrow. When the electrode width is narrow, it tends to be difficult to collect the solder of the conductive particles on the electrode. However, in the present invention, even if the electrode width is narrow, it is possible to sufficiently collect the solder on the electrode. In the present invention, since the above-mentioned structure is provided, when the electrodes are electrically connected, the solder in the conductive particles is easy to be located between the upper and lower opposing electrodes, and the solder in the conductive particles is connected to the electrode ( It can be placed efficiently on the line. Additionally, in the present invention, when the electrode width is wide, the solder in the conductive particles is more efficiently disposed on the electrode.

Additionally, it is difficult for a part of the solder in the conductive particles to be placed in the area (space) where the electrode is not formed, and the amount of solder placed in the area where the electrode is not formed can be significantly reduced. In the present invention, solder that is not located between opposing electrodes can be efficiently moved between opposing electrodes. Therefore, the reliability of conduction between electrodes can be increased. In addition, electrical connection between horizontally adjacent electrodes that should not be connected can be prevented, and insulation reliability can be improved.

Additionally, in the present invention, the heat resistance of the cured product of the conductive material can be improved. In particular, when a conductive material is used in an optical semiconductor device, heat is generated when irradiated with light, and the cured product of the conductive material is exposed to high temperatures. Since the electrically conductive material according to the present invention is excellent in heat resistance of the cured product, it can be suitably used in an optical semiconductor device. In particular, when the thermosetting compound contains a thermosetting compound having a triazine skeleton, the heat resistance of the cured product increases.

Additionally, in the present invention, positional misalignment between electrodes can be prevented. In the present invention, when the second connection target member is overlapped with the first connection target member on which a conductive material is disposed on the upper surface, the alignment of the electrodes of the first connection target member and the electrode of the second connection target member is misaligned, Even when the first connection target member and the second connection target member overlap, the misalignment can be corrected and the electrode of the first connection target member can be connected to the electrode of the second connection target member (self-alignment effect).

In order to more efficiently arrange the solder in the conductive particles on the electrode, the conductive material is preferably in a liquid state at 25°C, and is preferably a conductive paste. In order to more efficiently arrange the solder in the conductive particles on the electrode, the viscosity (η25) at 25°C of the conductive material is preferably 10 Pa·s or more, more preferably 50 Pa·s or more, even more preferably Preferably it is 100 Pa·s or more, preferably 800 Pa·s or less, more preferably 600 Pa·s or less, and even more preferably 500 Pa·s or less. The viscosity (η25) can be appropriately adjusted depending on the type and amount of blended ingredients.

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

The above-mentioned electrically conductive material can be used as a conductive paste, a conductive film, etc. It is preferable that the conductive film is an anisotropic conductive film. From the viewpoint of more efficiently disposing the solder in the conductive particles on the electrode, it is preferable that the electrically conductive material is an electrically conductive paste. The above-mentioned conductive material is suitably used for electrical connection of electrodes. It is preferable that the said electrically-conductive material is a circuit connection material.

Hereinafter, each component contained in the above-mentioned conductive material will be described. In addition, in this specification, “(meth)acrylate” means one or both of “acrylate” and “methacrylate”, and “(meth)acrylic” means either “acrylic” or “methacrylate”. Or it means both, and “(meth)acryloyl” means one or both of “acryloyl” and “methacryloyl”.

(Conductive particles)

The electrically conductive particles electrically connect electrodes of connection target members. The electrically conductive particles have solder on the outer surface of the electrically conductive portion. The conductive particles may be solder particles formed from solder. The solder particles have solder on the outer surface of the conductive portion. As for the solder particles, both the center portion and the outer surface portion of the conductive portion are formed of solder. The solder particles are particles in which both the center portion and the conductive outer surface are solder. The solder particles are core particles and do not have base particles. The said solder particle is different from a substrate particle and an electroconductive particle provided with the electrically conductive part arrange|positioned on the surface of the said substrate particle. The solder particles, for example, preferably contain solder in an amount of 80% by weight or more, more preferably 90% by weight or more, and even more preferably 95% by weight or more. The said electroconductive particle may have a substrate particle and an electrically conductive part arrange|positioned on the surface of the said substrate particle. In this case, the conductive particles have solder on the outer surface portion of the conductive portion.

Furthermore, compared to the case where the solder particles are used, when conductive particles including base particles not formed of solder and solder portions disposed on the surface of the base particles are used, it becomes difficult for the conductive particles to gather on the electrode, Since the solder bondability between conductive particles is low, conductive particles that have moved on the electrode tend to move outside the electrode, and the effect of suppressing misalignment between electrodes also tends to decrease. Therefore, it is preferable that the conductive particles are solder particles formed by solder.

From the viewpoint of effectively lowering the connection resistance in the connection structure and effectively suppressing the generation of voids, it is preferable that a carboxyl group or an amino group is present on the outer surface of the conductive particle (outer surface of the solder), and the carboxyl group is present. It is preferable that an amino group is present. It is preferable that a group containing a carboxyl group or an amino group is covalently bonded to the outer surface of the conductive particles (outer surface of solder) through a Si-O bond, an ether bond, an ester bond, or a group represented by the following formula (X). do. The group containing a carboxyl group or an amino group may contain both a carboxyl group and an amino group. Additionally, in the following formula (X), the right end and left end represent binding sites.

Hydroxyl groups exist on the surface of the solder. By covalently bonding a group containing a hydroxyl group to a carboxyl group, a stronger bond can be formed than when bonding through other coordination bonds (chelate coordination), etc., so the connection resistance between electrodes is lowered and the generation of voids is suppressed. Possible conductive particles are obtained.

In the above-described conductive particles, the bond between the surface of the solder and the group containing the carboxyl group does not need to contain a coordination bond, nor does it need to include a bond by chelate coordination.

From the viewpoint of effectively lowering the connection resistance in the connection structure and effectively suppressing the generation of voids, the conductive particles are compounds having a carboxyl group or an amino group and a functional group capable of reacting with a hydroxyl group (hereinafter sometimes referred to as compound ) is preferably obtained by reacting a functional group that can react with the hydroxyl group with the hydroxyl group on the surface of the solder. In this reaction, a covalent bond is formed. By reacting a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group in the compound It is also possible to obtain solder particles in which a group containing a carboxyl group or an amino group is covalently bonded through a bond or ester bond. By reacting a functional group capable of reacting with the hydroxyl group on the surface of the solder, the compound

Functional groups capable of reacting with the hydroxyl group include hydroxyl group, carboxyl group, ester group, and carbonyl group. Hydroxyl or carboxyl groups are preferred. The functional group capable of reacting with the hydroxyl group may be a hydroxyl group or a carboxyl group.

Compounds having a functional group capable of reacting with a hydroxyl group include levulinic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, and 4-aminobutyric acid. , 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecane Acids, hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid and dodecanoic acid. etc. can be mentioned. Glutaric acid or glycolic acid is preferred. Only one type of compound having a functional group capable of reacting with the hydroxyl group may be used, or two or more types may be used in combination. The compound having a functional group capable of reacting with the hydroxyl group is preferably a compound having at least one carboxyl group.

The compound A compound having a flux action can remove the surface oxide film of the solder and the surface oxide film of the electrode. The carboxyl group has a flux action.

Compounds having a flux effect include levulinic acid, glutaric acid, glycolic acid, adipic acid, succinic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, and 3-mercap. Examples include toisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, and 4-phenylbutyric acid. Glutaric acid, adipic acid or glycolic acid are preferred. Only one type of compound having the above flux action may be used, or two or more types may be used in combination.

From the viewpoint of effectively lowering the connection resistance in the connected structure and effectively suppressing the generation of voids, it is preferable that the functional group capable of reacting with the hydroxyl group in the compound X is a hydroxyl group or a carboxyl group. The functional group capable of reacting with the hydroxyl group in the compound When the functional group capable of reacting with the hydroxyl group is a carboxyl group, it is preferable that the compound X has at least two carboxyl groups. By reacting some of the carboxyl groups of a compound having at least two carboxyl groups with hydroxyl groups on the surface of the solder, conductive particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder are obtained.

The method for producing the conductive particles includes, for example, a step of using the conductive particles and mixing the conductive particles, a compound having a functional group and a carboxyl group capable of reacting with hydroxyl group, a catalyst, and a solvent. In the method for producing conductive particles, conductive particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be easily obtained through the mixing step.

In addition, in the method for producing the conductive particles, it is preferable to use the conductive particles, mix the conductive particles, a compound having a functional group and a carboxyl group capable of reacting with the hydroxyl group, the catalyst, and the solvent, and then heat the mixture. Through the mixing and heating process, conductive particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be more easily obtained.

Examples of the solvent include alcohol solvents such as methanol, ethanol, propanol, and butanol, acetone, methyl ethyl ketone, ethyl acetate, toluene, and xylene. The solvent is preferably an organic solvent, and more preferably toluene. As for the said solvent, only 1 type may be used, and 2 or more types may be used together.

Examples of the catalyst include p-toluenesulfonic acid, benzenesulfonic acid, and 10-camphorsulfonic acid. The catalyst is preferably p-toluenesulfonic acid. Only one type of the said catalyst may be used, and two or more types may be used together.

It is preferable to heat during the mixing. The heating temperature is preferably 90°C or higher, more preferably 100°C or higher, preferably 130°C or lower, and more preferably 110°C or lower.

From the viewpoint of effectively lowering the connection resistance in the connection structure and effectively suppressing the generation of voids, the conductive particles are obtained through a step of using an isocyanate compound and reacting the isocyanate compound with the hydroxyl group on the solder surface. desirable. In this reaction, a covalent bond is formed. By reacting the hydroxyl group on the surface of the solder with the above-mentioned isocyanate compound, conductive particles in which the nitrogen atom of the group derived from the isocyanate group is covalently bonded to the surface of the solder can be easily obtained. By reacting the isocyanate compound with the hydroxyl group on the solder surface, the group derived from the isocyanate group can be chemically bonded to the surface of the solder in the form of a covalent bond.

Additionally, a silane coupling agent can be easily reacted with a group derived from an isocyanate group. Since the above-described conductive particles can be easily obtained, the group containing the carboxyl group is introduced by reaction using a silane coupling agent having a carboxyl group, or the carboxyl group is added to a group derived from the silane coupling agent after reaction using a silane coupling agent. It is preferable that it is introduced by reacting a compound having at least one. The conductive particles are preferably obtained by using the isocyanate compound to react with a hydroxyl group on the solder surface, and then reacting the isocyanate compound with a compound having at least one carboxyl group.

From the viewpoint of effectively lowering the connection resistance in the connected structure and effectively suppressing the generation of voids, it is preferable that the compound having at least one carboxyl group has a plurality of carboxyl groups.

Examples of the isocyanate compound include diphenylmethane-4,4'-diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI). Isocyanate compounds other than these may be used. After reacting this compound with the surface of the solder, a residual isocyanate group is reacted with a compound that is reactive with the residual isocyanate group and also has a carboxyl group, thereby introducing a carboxyl group to the surface of the solder through the group represented by the formula (X). can do.

As the isocyanate compound, a compound having an unsaturated double bond and an isocyanate group may be used. Examples include 2-acryloyloxyethyl isocyanate and 2-isocyanatoethyl methacrylate. After reacting the isocyanate group of this compound with the surface of the solder, a compound having a functional group reactive to the remaining unsaturated double bond and also having a carboxyl group is reacted to form a group represented by the formula (X) on the surface of the solder. Thus, a carboxyl group can be introduced.

Examples of the silane coupling agent include 3-isocyanate propyltriethoxysilane (“KBE-9007” manufactured by Shin-Etsu Silicone) and 3-isocyanate propyltrimethoxysilane (“Y-5187” manufactured by MOMENTIVE). As for the said silane coupling agent, only 1 type may be used, and 2 or more types may be used together.

Compounds having at least one carboxyl group include levulinic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3 -Mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid and dodecanedioic acid. I can hear it. Glutaric acid, adipic acid or glycolic acid are preferred. Only one type of the compound having at least one carboxyl group may be used, or two or more types may be used in combination.

Using the isocyanate compound, a group containing a carboxyl group can remain by reacting the isocyanate compound with the hydroxyl group on the solder surface and then reacting some of the carboxyl groups of the compound having a plurality of carboxyl groups with the hydroxyl group on the solder surface.

In the method for producing conductive particles, conductive particles are used and an isocyanate compound is used to react the isocyanate compound with a hydroxyl group on the surface of the solder, and then react with a compound having at least one carboxyl group to form a compound on the surface of the solder. , to obtain conductive particles to which a group containing a carboxyl group is bonded through the group represented by the formula (X). In the method for producing conductive particles, conductive particles into which a group containing a carboxyl group is introduced into the surface of the solder can be easily obtained through the above-mentioned process.

Specific methods for producing the electrically conductive particles include the following methods. Conductive particles are dispersed in an organic solvent, and a silane coupling agent having an isocyanate group is added. Thereafter, a silane coupling agent is covalently bonded to the surface of the solder using a reaction catalyst between the hydroxyl group and the isocyanate group on the solder surface of the conductive particles. Next, the alkoxy group bonded to the silicon atom of the silane coupling agent is hydrolyzed to generate a hydroxyl group. The resulting hydroxyl group is reacted with the carboxyl group of a compound having at least one carboxyl group.

In addition, the following method is mentioned as a specific manufacturing method of the said electroconductive particle. Conductive particles are dispersed in an organic solvent, and a compound having an isocyanate group and an unsaturated double bond is added. After that, a covalent bond is formed using a reaction catalyst between the hydroxyl group and the isocyanate group on the solder surface of the conductive particles. Thereafter, a compound having an unsaturated double bond and a carboxyl group is reacted with the introduced unsaturated double bond.

Catalysts for the reaction of hydroxyl groups and isocyanate groups on the solder surface of conductive particles include tin-based catalysts (dibutyl tin dilaurate, etc.), amine-based catalysts (triethylenediamine, etc.), and carboxylate catalysts (lead naphthenate, potassium acetate, etc.) ) and trialkylphosphine catalysts (triethylphosphine, etc.).

From the viewpoint of effectively lowering the connection resistance in the connected structure and effectively suppressing the generation of voids, the compound having at least one carboxyl group is preferably a compound represented by the following formula (1). The compound represented by the following formula (1) has a flux effect. Additionally, the compound represented by the following formula (1) has a flux effect when introduced into the surface of the solder.

In the above formula (1), X represents a functional group capable of reacting with a hydroxyl group, and R represents a divalent organic group having 1 to 5 carbon atoms. The organic group may contain a carbon atom, a hydrogen atom, and an oxygen atom. The organic group may be a divalent hydrocarbon group having 1 to 5 carbon atoms. The main chain of the organic group is preferably a divalent hydrocarbon group. In the organic group, a carboxyl group or a hydroxyl group may be bonded to a divalent hydrocarbon group. The compound represented by the formula (1) includes, for example, citric acid.

The compound having at least one carboxyl group is preferably a compound represented by the following formula (1A) or the following formula (1B). The compound having at least one carboxyl group is preferably a compound represented by the following formula (1A), and more preferably a compound represented by the following formula (1B).

In the above formula (1A), R represents a divalent organic group having 1 to 5 carbon atoms. R in the above formula (1A) is the same as R in the above formula (1).

In the above formula (1B), R represents a divalent organic group having 1 to 5 carbon atoms. R in the formula (1B) is the same as R in the formula (1).

It is preferable that a group represented by the following formula (2A) or the following formula (2B) is bonded to the surface of the solder. It is preferable that the group represented by the following formula (2A) is bonded to the surface of the solder, and it is more preferable that the group represented by the following formula (2B) is bonded. In addition, in the following formula (2A) and the following formula (2B), the left end represents a binding site.

In the above formula (2A), R represents a divalent organic group having 1 to 5 carbon atoms. R in the formula (2A) is the same as R in the formula (1).

In the formula (2B), R represents a divalent organic group having 1 to 5 carbon atoms. R in the formula (2B) is the same as R in the formula (1).

From the viewpoint of increasing the surface wettability of the solder, the molecular weight of the compound having at least one carboxyl group is preferably 10000 or less, more preferably 1000 or less, and even more preferably 500 or less. From the viewpoint of suppressing migration more effectively and from the viewpoint of more effectively lowering the connection resistance in the bonded structure, the molecular weight of the compound having at least one carboxyl group is preferably 80 or more, more preferably 100 or more, and further. Preferably it is 120 or more.

The molecular weight refers to a molecular weight that can be calculated from the structural formula when the compound having at least one carboxyl group is not a polymer and when the structural formula of the compound having at least one carboxyl group can be specified. In addition, when the compound having at least one carboxyl group is a polymer, it means the weight average molecular weight.

In order to effectively increase the cohesiveness of the conductive particles during conductive connection, it is preferable that the conductive particles have a conductive particle body and an anionic polymer disposed on the surface of the conductive particle body. The conductive particles are preferably obtained by surface treating the conductive particle body with an anionic polymer or a compound that becomes an anionic polymer. The conductive particles are preferably surface-treated with an anionic polymer or a compound that becomes an anionic polymer. As for the anionic polymer and the compound forming the anionic polymer, only one type may be used, or two or more types may be used in combination. The anionic polymer is a polymer having an acidic group.

As a method of surface treating the conductive particle body with an anionic polymer, the anionic polymer includes, for example, (meth)acrylic polymer copolymerized with (meth)acrylic acid, polyester synthesized from dicarboxylic acid and diol and having carboxyl groups at both ends. Polymers, polymers obtained by intermolecular dehydration condensation reaction of dicarboxylic acids and having carboxyl groups at both ends, polyester polymers synthesized from dicarboxylic acids and diamines and having carboxyl groups at both ends, and modified foams having carboxyl groups ( A method of reacting the carboxyl group of the anionic polymer with the surface hydroxyl group of the conductive particle body using a product such as “Kosenetkusu T” manufactured by Nippon Kosei Chemical Co., Ltd. is included.

Examples of the anionic portion of the anionic polymer include the carboxyl group, and others include tosyl group (pH ₃ CC ₆ H ₄ S(=O) ₂ ^- ), sulfonic acid ion group (-SO ₃ ^- ), and phosphate ion group ( -PO ₄ ^- ), etc. may be mentioned.

Another method of surface treatment is to use a compound that has a functional group that reacts with the surface hydroxyl group of the conductive particle body and also has a functional group that can be polymerized through addition and condensation reactions, and to polymerize this compound on the surface of the conductive particle body. There are ways to reconcile. Functional groups that react with the surface hydroxyl group of the conductive particle main body include carboxyl groups and isocyanate groups, and functional groups that polymerize through addition and condensation reactions include hydroxyl groups, carboxyl groups, amino groups, and (meth)acryloyl groups.

The weight average molecular weight of the anionic polymer is preferably 2000 or more, more preferably 3000 or more, preferably 10000 or less, and more preferably 8000 or less. If the weight average molecular weight is equal to or greater than the lower limit and equal to or lower than the upper limit, a sufficient amount of charge and flux can be introduced into the surface of the conductive particles. As a result, the cohesion of the conductive particles can be effectively increased during conductive connection, and the surface oxide film of the electrode can be effectively removed when connecting the member to be connected.

If the weight average molecular weight is equal to or greater than the lower limit and equal to or lower than the upper limit, it is easy to dispose the anionic polymer on the surface of the conductive particle body, the cohesiveness of the conductive particles can be effectively increased during conductive connection, and the conductive particles are placed on the electrodes. It can be deployed more efficiently.

The above weight average molecular weight represents the weight average molecular weight in polystyrene conversion measured by gel permeation chromatography (GPC).

The weight average molecular weight of the polymer obtained by surface treating the conductive particle body with a compound that becomes an anionic polymer is the weight average molecular weight of the remaining polymer after dissolving the solder in the conductive particles and removing the conductive particles with diluted hydrochloric acid, which does not cause decomposition of the polymer. It can be obtained by measuring the weight average molecular weight.

Regarding the amount of anionic polymer introduced onto the surface of the conductive particles, the acid value per 1g of conductive particles is preferably 1 mgKOH or more, more preferably 2 mgKOH or more, preferably 10 mgKOH or less, and more preferably 6 mgKOH or less.

The acid value can be measured as follows. 1 g of conductive particles were added to 36 g of acetone and dispersed by ultrasonic waves for 1 minute. Thereafter, titration is performed with 0.1 mol/L potassium hydroxide ethanol solution using phenolphthalein as an indicator.

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 in an electrically conductive material.

The conductive particles 21 shown in FIG. 4 are solder particles. The conductive particles 21 are formed entirely of solder. The conductive particles 21 do not have substrate particles in their cores and are not core-shell particles. As for the conductive particles 21, both the center portion and the outer surface portion of the conductive portion are formed with solder.

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

The electroconductive particle 31 shown in FIG. 5 is provided with the substrate particle 32 and the electrically conductive part 33 arrange|positioned on the surface of the substrate particle 32. The conductive portion 33 covers the surface of the substrate particle 32. The electrically conductive particles 31 are coated particles in which the surface of the substrate particle 32 is covered with the electrically conductive portion 33 .

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

Fig. 6 is a cross-sectional view showing a third example of conductive particles that can be used in electrically conductive materials.

As described above, the conductive portion 33 of the conductive particles 31 has a two-layer structure. The conductive particle 41 shown in FIG. 6 is a single-layer conductive portion and has a solder portion 42. The conductive particles 41 include substrate particles 32 and solder portions 42 disposed on the surface of the substrate particles 32 .

Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. It is preferable that the said substrate particle is a substrate particle excluding a metal, and it is preferable that it is a resin particle, an inorganic particle excluding a metal particle, or an organic-inorganic hybrid particle. The said substrate particle may be a copper particle.

As a resin for forming the resin particles, various organic substances are suitably used. Resins for forming the resin particles include, for example, polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; Acrylic resins such as polymethyl methacrylate and polymethyl acrylate; 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, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer, and divinylbenzene-based copolymer. etc. can be mentioned. Examples of the divinylbenzene-based copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylic acid ester copolymer. Since the hardness of the resin particles can be easily controlled to an appropriate range, the resin for forming the resin particles is preferably a polymer obtained by polymerizing one or two or more types of polymerizable monomers having an ethylenically unsaturated group.

When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, examples of the polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkable monomers.

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; Carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth) Alkyl (meth)acrylate compounds such as acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; oxygen atom-containing (meth)acrylate compounds such as 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate; Nitrile-containing monomers such as (meth)acrylonitrile; Vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; Acid vinyl ester compounds such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate; Unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; and halogen-containing monomers such as trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene.

Examples of the crosslinkable monomer include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. Latex, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate polyfunctional (meth)acrylate compounds such as polyester, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; Triallyl (iso)cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilyl styrene. and silane-containing monomers such as vinyltrimethoxysilane.

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

When the substrate particles are inorganic particles other than metal or organic-inorganic hybrid particles, examples of inorganic materials for forming the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. The particles formed from the above silica are not particularly limited, but examples include particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form cross-linked polymer particles, and then performing baking as necessary. You can. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

When the substrate particle is a metal particle, metals for forming the metal particle include silver, copper, nickel, silicon, gold, and titanium. When the substrate particles are metal particles, it is preferable that the metal particles are copper particles. However, it is preferable that the substrate particles are not metal particles.

The method of forming an electrically conductive portion on the surface of the substrate particle and the method of forming a solder portion on the surface of the substrate particle or the surface of the second electrically conductive portion are not particularly limited. Methods for forming the conductive portion and the solder portion include, for example, electroless plating, electroplating, physical collision, mechanochemical reaction, physical vapor deposition, or physical adsorption. and a method of coating the surface of the base particle with a metal powder or a paste containing a metal powder and a binder. Methods using electroless plating, electroplating, or physical impact are suitable. Examples of the physical vapor deposition method include vacuum deposition, ion plating, and ion sputtering. In addition, in the method using physical collision, for example, Theta Composer (manufactured by Tokuju Kosakusho Co., Ltd.) is used.

The melting point of the substrate particles is preferably higher than the melting point of the solder portion. The melting point of the substrate particles is preferably greater than 160°C, more preferably greater than 300°C, further preferably greater than 400°C, and particularly preferably greater than 450°C. Additionally, the melting point of the substrate particles may be less than 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 be less than 260°C.

The conductive particles may have a single-layer solder portion. The conductive particles may have multiple layers of conductive portions (solder portion, second conductive portion). That is, in the above-described conductive particles, two or more layers of conductive portions may be laminated.

The solder is preferably a metal with a melting point of 450°C or lower (low melting point metal). The solder portion is preferably a metal layer (low melting point metal layer) with 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 a metal particle (low melting point metal particle) with a melting point of 450°C or lower. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal refers to a metal with a melting point of 450°C or lower. The melting point of the low melting point metal is preferably 300°C or lower, more preferably 160°C or lower. Additionally, it is preferable that the solder in the conductive particles contains tin. Among 100% by weight of metal contained in the solder portion and 100% by weight of metal contained in the solder in the conductive particles, the tin content is preferably 30% by weight or more, more preferably 40% by weight or more, and further. Preferably it is 70% by weight or more, particularly preferably 90% by weight or more. If the content of tin in the solder in the conductive particles is more than the above lower limit, the reliability of conduction between the conductive particles and the electrode increases further.

In addition, the tin content was determined using a high-frequency inductively coupled plasma emission spectrometer (“ICP-AES” manufactured by Horiba Seisakusho Co., Ltd.) or a fluorescence X-ray analyzer (“EDX-800HS” manufactured by Shimadzu Seisakusho Co., Ltd.). It can be measured.

By using conductive particles having the solder on the outer surface portion of the conductive portion, the solder melts and joins the electrodes, and the solder conducts electricity between the electrodes. For example, since solder and electrodes tend to make surface contact rather than point contact, the connection resistance is lowered. In addition, the use of conductive particles having solder on the outer surface of the conductive portion increases the bonding strength between the solder and the electrode, making it more difficult for the solder to peel off and effectively increasing the reliability of conduction.

The low melting point metal constituting the solder portion and the solder particles is not particularly limited. The low melting point metal is preferably tin or an alloy containing tin. The alloy may include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, tin-indium alloy, etc. In terms of excellent wettability to the electrode, the low melting point metal is preferably tin, tin-silver alloy, tin-silver-copper alloy, tin-bismuth alloy, or tin-indium alloy. It is more preferable that it is a tin-bismuth alloy or a tin-indium alloy.

The material constituting the solder (solder portion) is preferably a filler metal with a liquidus line of 450°C or lower based on JIS Z3001: Welding Terminology. Examples of the composition of the solder include metal compositions containing zinc, gold, silver, lead, copper, tin, bismuth, indium, etc. A tin-indium system (117°C process) or a tin-bismuth system (139°C process) that is lead-free and has a low melting point is preferred. That is, the solder preferably does not contain lead, and is preferably a solder containing tin and indium, or a solder containing tin and bismuth.

In order to further increase the bonding strength between the solder and the electrode, the solder in the conductive particles contains nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, It may contain metals such as chromium, molybdenum, and palladium. Additionally, from the viewpoint of further increasing the bonding strength between the solder and the electrode, it is preferable that the solder in the conductive particles contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing 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 preferably 0.0001% by weight based on 100% by weight of the solder in the conductive particles. % or more, preferably 1 weight% or less.

The melting point of the second conductive portion is preferably higher than the melting point of the solder portion. The melting point of the second conductive portion is preferably greater than 160°C, more preferably greater than 300°C, even more preferably greater than 400°C, even more preferably greater than 450°C, and particularly preferably exceeds 500°C, and most preferably exceeds 600°C. Since the solder portion has a low melting point, it melts during conductive connection. It is preferable that the second conductive portion does not melt during conductive connection. The conductive particles are preferably used by melting the solder, and are preferably used by melting the solder portion, and are preferably used by melting the solder portion and without melting the second conductive portion. Since the melting point of the second conductive portion is higher than that of the solder portion, only the solder portion can be melted without melting the second conductive portion during conductive connection.

The absolute value of the difference between the melting point of the solder portion and the melting point of the second conductive portion exceeds 0°C, preferably 5°C or higher, more preferably 10°C or higher, further preferably 30°C or higher, especially preferably Typically, it is 50°C or higher, particularly preferably 100°C or higher.

The second conductive portion preferably contains metal. The metal constituting the second conductive portion is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, and alloys thereof. Additionally, as the metal, tin-doped indium oxide (ITO) may be used. Only one type of the said metal may be used, and two or more types may be used together.

The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer or a gold layer, and even more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably have a nickel layer or a gold layer, and even more preferably have a copper layer. By using conductive particles having these preferable conductive parts for the connection between electrodes, the connection resistance between electrodes is further lowered. Additionally, solder portions can be formed more easily on the surfaces of these preferable conductive portions.

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

The thickness of the conductive portion (thickness of the entire conductive portion) is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.5 μm. or less, particularly preferably 0.3 μm or less. The thickness of the conductive portion is the thickness of the entire conductive layer when the conductive portion is multilayered. If the thickness of the conductive portion is equal to or greater than the lower limit and equal to or less than the upper limit, sufficient conductivity is obtained, the conductive particles do not become too hard, and the conductive particles are sufficiently deformed during connection between electrodes.

When the conductive portion is formed of a plurality of layers, the thickness of the conductive layer of the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, more preferably 0.1 μm or more. It is less than ㎛. If the thickness of the conductive layer of the outermost layer is equal to or greater than the lower limit and equal to or less than the upper limit, the coating by the conductive layer of the outermost layer becomes uniform, corrosion resistance sufficiently increases, and the connection resistance between electrodes further decreases. Additionally, when the outermost layer is a gold layer, the thinner the thickness of the gold layer, the lower the cost.

The thickness of the conductive portion can be measured by observing the cross section of the conductive particle using, for example, a field emission scanning electron microscope (FE-SEM).

The obtained conductive particles are added to "Techno Bit 4000" manufactured by Kulzer so that the content is 30% by weight, dispersed, and an embedding resin for conductive particle inspection is produced. Using an ion milling device (“IM4000” manufactured by Hitachi High Technologies), a cross section of the conductive particles is cut so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin for inspection.

Then, using a field emission scanning electron microscope (FE-SEM), it is preferable to set the image magnification to 50,000 times, randomly select 50 conductive particles, and observe the conductive portion of each conductive particle. It is preferable to measure the thickness of the electrically conductive portion in the obtained electrically conductive particles and calculate the arithmetic average to obtain the thickness of the electrically conductive portion.

The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, preferably 100 μm or less, more preferably 50 μm or less, even more preferably Typically, it is 40 μm or less, particularly preferably 30 μm or less. If the average particle diameter of the conductive particles is equal to or greater than the lower limit and equal to or less than the upper limit, the solder in the conductive particles can be disposed more efficiently on the electrodes, and it is better to place a large amount of solder in the conductive particles between the electrodes. It is easy and conduction reliability is further improved.

The “average particle diameter” of the electrically conductive particles represents the number average particle diameter. The average particle diameter of the conductive particles is determined, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average value.

Additionally, the average particle diameter of the conductive particles is generally the same for the conductive particles alone before being mixed with the thermosetting component and flux, and the conductive particles in the conductive material after being mixed with the thermosetting component and flux.

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

In 100% by weight of the electrically conductive material, the content of the conductive particles is preferably 1% by weight or more, more preferably 2% by weight or more, further preferably 10% by weight or more, particularly preferably 20% by weight or more, especially Preferably it is 30% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, further preferably 60% by weight or less, and particularly preferably 50% by weight or less. If the content of the conductive particles is more than the lower limit and less than the upper limit, the solder in the conductive particles can be placed on the electrodes more efficiently, and it is easy to place a large amount of the solder in the conductive particles between the electrodes. , continuity reliability is further improved. From the viewpoint of further improving conduction reliability, it is preferable that the content of the conductive particles is higher.

(thermosetting compound)

The thermosetting compound is a compound that can be cured by heating. Examples of the thermosetting compounds include oxetane compounds, epoxy compounds, episulfide compounds, (meth)acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. From the viewpoint of further improving the curability and viscosity of the electrically conductive material and further improving conduction reliability and connection reliability, an epoxy compound or an episulfide compound is preferable, and an epoxy compound is more preferable. It is preferable that the said electrically-conductive material contains an epoxy compound. As for the said thermosetting compound, only 1 type may be used, and 2 or more types may be used together.

From the viewpoint of effectively increasing the heat resistance of the cured product and effectively lowering the dielectric constant of the cured product, the thermosetting compound preferably contains a thermosetting compound having a nitrogen atom, and more preferably contains a thermosetting compound having a triazine skeleton. do.

Examples of the thermosetting compound having the triazine skeleton include triazine triglycidyl ether, and the TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC manufactured by Nissan Chemical Industries, Ltd.) -PAS, TEPIC-VL, TEPIC-UC), etc.

Examples of the epoxy compound include aromatic epoxy compounds. Crystalline epoxy compounds such as resorcinol-type epoxy compounds, naphthalene-type epoxy compounds, biphenyl-type epoxy compounds, and benzophenone-type epoxy compounds are preferable. An epoxy compound that is solid at room temperature (23°C) and has a melting temperature below the melting point of solder is preferred. The melting temperature is preferably 100°C or lower, more preferably 80°C or lower, and preferably 40°C or higher. In the step of joining the connection target members by using the above preferred epoxy compound, the viscosity is high, and when acceleration is applied due to impact such as conveyance, positional deviation of the first connection target member and the second connection target member is suppressed. Moreover, the heat during curing can significantly reduce the viscosity of the conductive material, and agglomeration of the solder can be promoted efficiently.

Among 100% by weight of the electrically conductive material, the content of the thermosetting compound is preferably 20% by weight or more, more preferably 40% by weight or more, further preferably 50% by weight or more, preferably 99% by weight or less, More preferably, it is 98 weight% or less, further preferably 90 weight% or less, and particularly preferably 80 weight% or less. From the viewpoint of further improving impact resistance, it is preferable that the content of the thermosetting compound is higher.

(thermal curing agent)

The thermosetting agent thermocures the thermosetting compound. Examples of the thermal curing agent include imidazole curing agents, phenol curing agents, thiol curing agents, amine curing agents, acid anhydride curing agents, thermal cationic initiators, and thermal radical generators. As for the said thermosetting agent, only 1 type may be used, and 2 or more types may be used together.

The imidazole curing agent is not particularly limited and includes 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-triazine and 2,4-diamino-6-[2' -methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, etc. are mentioned.

The thiol curing agent is not particularly limited and includes trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. can be mentioned.

The solubility parameter of the thiol curing agent is preferably 9.5 or more, and preferably 12 or less. The solubility parameter is calculated by the Fedors method. For example, the solubility parameter of trimethylolpropanetris-3-mercaptopropionate is 9.6, and the solubility parameter of dipentaerythritol hexa-3-mercaptopropionate is 11.4.

The amine curing agent is not particularly limited and includes hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5.5]undecane, and bis. (4-aminocyclohexyl)methane, metaphenylenediamine, and diaminodiphenylsulfone.

Examples of the thermal cationic initiator include iodonium-based cationic curing agents, oxonium-based cationic curing agents, and sulfonium-based cationic curing agents. Examples of the iodonium-based cationic curing agent include bis(4-tert-butylphenyl)iodonium hexafluorophosphate. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolyl sulfonium hexafluorophosphate.

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

The reaction start temperature of the thermosetting agent is preferably 50°C or higher, more preferably 70°C or higher, further preferably 80°C or higher, preferably 250°C or lower, more preferably 200°C or lower, even more preferably Typically, it is 150°C or lower, particularly preferably 140°C or lower. If the reaction start temperature of the thermosetting agent is higher than the lower limit and lower than the upper limit, the solder in the conductive particles is more efficiently disposed on the electrode. It is particularly preferable that the reaction start temperature of the thermosetting agent is 80°C or more and 140°C or less.

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

The reaction start temperature of the thermosetting agent means the temperature at which the exothermic peak in DSC starts to rise.

The content of the thermosetting agent is not particularly limited. With respect to 100 parts by weight of the thermosetting compound, the content of the thermosetting agent is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less. , more preferably 75 parts by weight or less. If the content of the thermosetting agent is more than the above lower limit, it is easy to sufficiently cure the conductive material. If the content of the thermosetting agent is below the above upper limit, it becomes difficult for excess thermosetting agent not involved in curing to remain after curing, and the heat resistance of the cured product further increases.

(flux)

The conductive material includes flux. By using flux, solder in conductive particles can be placed on the electrode more effectively. Additionally, in the present invention, the flux is a combination of an acid that has the effect of cleaning the surface of a metal and a base that has the effect of neutralizing the acid, and is a salt of these acids and bases.

If the flux, which is a salt of this specific acid and base, is solid at 25°C, the storage stability of the conductive material increases, and after the conductive material is placed on the member to be connected, it exhibits excellent solder cohesion even if left for a long time, resulting in high conduction reliability. It is possible to provide conductive materials that can be developed. The flux is preferably a salt of an acid and a base and is solid at 25°C.

The flux is, for example, a salt of an organic compound having a carboxyl group and a compound having an amino group, and is preferably a salt of an organic compound having a carboxyl group and an organic compound having an amino group.

In addition, from the viewpoint of effectively increasing the storage stability of the conductive material, exhibiting excellent solder cohesion even if left for a long time after the conductive material is placed on the connection target member, and demonstrating high conduction reliability, the flux, which is a salt of a specific acid and base, is used. It is preferred that it is solid at 25°C. Only one type of the said flux may be used, and two or more types may be used together.

The flux can be obtained, for example, by neutralizing a carboxylic acid or carboxylic acid anhydride and an amino group-containing compound. The flux is preferably a neutralization reaction product between carboxylic acid or carboxylic acid anhydride and an amino group-containing compound.

Examples of the carboxylic acid or carboxylic acid anhydride include aliphatic carboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and malic acid, and cyclic aliphatic carboxylic acids such as cyclohexylcarboxylic acid and 1,4- Cyclohexyldicarboxylic acid, aromatic carboxylic acids such as isophthalic acid, terephthalic acid, trimellitic acid, and ethylenediaminetetraacetic acid, and their acid anhydrides.

In order to further enhance the flux effect, it is preferable that the acid and the organic compound having a carboxyl group have a plurality of carboxyl groups. Examples of organic compounds having multiple carboxyl groups include dicarboxylic acid and tricarboxylic acid. In order to facilitate the formation of salts, the acid and the organic compound having a carboxyl group preferably have an alkyl group, and the total number of carbon atoms of the alkyl group and the carboxyl group is preferably 4 or more, and preferably 8 or less.

To obtain the above reactant, an ester of carboxylic acid may be used. Examples of esters of carboxylic acids include alkyl esters of the above-mentioned carboxylic acids. Examples of the alkyl ester alkyl group of the above carboxylic acid include alkyl groups having 1 to 4 carbon atoms, and the number of carbon atoms of the alkyl group is preferably 3 or less, more preferably 2 or less.

Among the amino group-containing compounds, examples of the amino group-containing compounds that do not have an aromatic skeleton include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, and dicyclohexylamine.

Among the amino group-containing compounds, examples of the amino group-containing compounds having an aromatic skeleton include benzylamine, benzhydrylamine, 2-methylbenzylamine, 3-methylbenzylamine, and 4-tert-butylbenzylamine. Examples of secondary amines include N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine, and N-isopropylbenzylamine. Examples of tertiary amines include N,N-dimethylbenzylamine, imidazole compounds, and triazole compounds. From the viewpoint of effectively increasing the storage stability of the electrically conductive material and making it more difficult for components other than the electrically conductive particles to flow during connection between electrodes, the amino group-containing compound is preferably an aromatic amine compound or an aliphatic alicyclic amine compound.

The activation temperature (melting point) of the flux is preferably 40°C or higher, more preferably 50°C or higher. If the activation temperature of the flux is equal to or higher than the above lower limit, storage stability is further improved.

From the viewpoint of more efficiently disposing the solder in the conductive particles on the electrode, the melting point of the flux is preferably equal to or higher than the melting point of the solder in the conductive particles - 50°C or higher, and more preferably at least 50°C above the melting point of the solder in the conductive particles. The melting point of the solder in the conductive particles is -30°C or higher, preferably the melting point of the solder in the conductive particles is +50°C or lower, more preferably the melting point of the solder in the conductive particles is +30°C or lower, even more preferably. It is lower than the melting point of the solder in the conductive particles. If the melting point of the flux is equal to or higher than the lower limit and equal to or lower than the upper limit, the flux effect is exhibited more effectively and the solder is disposed on the electrode more efficiently.

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, and 10°C or higher. Lower is more preferable.

The flux may be dispersed in the electrically conductive material or may adhere to the surface of the electrically conductive particles.

In conductive materials at 25°C, the flux exists as a solid. When the flux is added in a uniformly dissolved state in the conductive material, the viscosity of the conductive material may increase due to a partial reaction between the thermosetting component and the flux. Additionally, when a conductive material is disposed on a member to be connected and the conductive material is in contact with air for a long period of time, the reaction between the flux and the thermosetting compound is accelerated by moisture in the air, or the reaction between the flux and the solder surface causes metal ions to form. This formation may adversely affect the cohesiveness of the solder or the insulation between adjacent electrodes. On the other hand, if the flux exists as a solid in a conductive material at 25°C, only the surface of the flux needs to be affected, so it can exhibit high storage stability and high conductivity and insulation even after being left for a long time.

In addition, in the conductive material at 25°C, the flux exists as a solid, and when the flux melts at a temperature lower than the melting point of the solder, when the conductive material is a paste, the flux exists as a solid at room temperature (23°C). Transformation can be given. As a result, sedimentation of the conductive particles can be prevented, shape retention after application can be achieved, and outflow of the conductive material into unnecessary locations can be further prevented. When the conductive material is a film, since the flux is solid, the liquid content in the conductive material can be reduced, so the cutability of the film can be improved and bleeding on the cut surface can be suppressed.

Additionally, when the flux melts at a temperature lower than the melting point of the solder, the melt viscosity of the conductive material is sufficiently lowered because the flux is dissolved at the melting point of the solder, and better solder cohesion can be exhibited.

In addition, when the flux dissolves at a temperature lower than the melting point of the solder, above the melting point of the solder, the flux dissolves in the thermosetting compound or thermosetting agent, and the carboxyl group and amino group of the flux react with the thermosetting compound or thermosetting agent. By doing so, the flux component is introduced into the curing system. As a result, high insulation between adjacent electrodes can be achieved and corrosion of the electrodes can be prevented.

Among electrically conductive materials at 25°C, the average particle diameter of the flux is preferably 30 μm or less. When the average particle diameter of the flux is within the above range, the flux can be present in the conductive material without reacting with the resin, and the storage stability of the conductive material can be further improved. For the same reason, the average particle diameter of the flux is preferably 0.1 μm or more.

The “average particle diameter” of the flux refers to the number average particle diameter. The average particle diameter of the flux is determined, for example, by observing 50 arbitrary conductive particles under an electron microscope or an optical microscope and calculating the average value.

Additionally, if there is no difference in the average particle diameter of the flux alone before being mixed with the conductive particles and thermosetting components, and the flux in the conductive material after being mixed with the conductive particles and thermosetting components, the flux may not be mixed with the conductive particles and thermosetting components. With the previous flux alone, the average particle diameter can be evaluated.

In addition, among the conductive materials at 25°C, the ratio of the average particle diameter of the flux to the average particle diameter of the conductive particles (average particle diameter of the flux/average particle diameter of the conductive particles) is preferably 3 or less, more preferably is 1 or less, more preferably 0.2 or less. If the ratio is below the upper limit, the flux can be brought into effective contact with the conductive particles, and the flux performance during heating can be further improved. For the same reason, the ratio (average particle diameter of flux/average particle diameter of conductive particles) is preferably 0.005 or more, more preferably 0.01 or more, and even more preferably 0.02 or more.

Among 100% by weight of the electrically conductive material, the content of the flux is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less.

(insulating particles)

From the viewpoint of controlling with high accuracy the gap between the connection target members connected by the cured product of the conductive material and the gap between the connection target members connected by solder in the conductive particles, the conductive material contains insulating particles. desirable. In the above-described electrically-conductive material, the insulating particles do not have to adhere to the surface of the electrically-conductive particles. Among the above-described electrically-conductive materials, it is preferable that the insulating particles exist while being spaced apart from the electrically-conductive particles.

The average particle diameter of the insulating particles is preferably 10 μm or more, more preferably 20 μm or more, further preferably 25 μm or more, preferably 100 μm or less, more preferably 75 μm or less, even more preferably Typically, it is 50㎛ or less. If the average particle diameter of the insulating particles is greater than or equal to the lower limit and less than or equal to the upper limit, the gap between the connection target members connected by the cured product of the conductive material and the gap between the connection target members connected by solder in the conductive particles are larger. It becomes more appropriate.

The “average particle diameter” of the insulating particles represents the number average particle diameter. The average particle diameter of the insulating particles is determined by, for example, observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average value.

Additionally, the average particle diameter of the insulating particles is generally the same for the insulating particles alone before being mixed with the conductive particles, thermosetting component, and flux, and the insulating particles in the conductive material after being mixed with the conductive particles, thermosetting component, and flux.

Materials for the insulating particles include insulating resin and insulating inorganic substances. Examples of the insulating resin include the resins mentioned above as resins for forming resin particles that can be used as substrate particles. Examples of the insulating inorganic material include the above-mentioned inorganic materials for forming inorganic particles that can be used as base particles.

Specific examples of the insulating resin that is the material of the insulating particles include polyolefins, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, crosslinked products of thermoplastic resins, thermosetting resins, and water-soluble resins. You can.

Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth)acrylate polymer include polymethyl (meth)acrylate, polyethyl (meth)acrylate, and polybutyl (meth)acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer and SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymer and vinyl copolymer. Examples of the thermosetting resin include epoxy resin, phenol resin, and melamine resin. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, and methylcellulose. Among them, water-soluble resin is preferable and polyvinyl alcohol is more preferable.

Among 100% by weight of the electrically conductive material, the content of the insulating particles is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less. The electrically conductive material does not need to contain insulating particles. If the content of the insulating particles is more than the above lower limit and less than the above upper limit, the gap between the connection target members connected by the cured product of the conductive material and the gap between the connection target members connected by solder in the conductive particles become more appropriate. .

(other ingredients)

The conductive material may contain various additives, such as fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, and flame retardants, as necessary. It may be included.

(Connection structure and method of manufacturing the connection structure)

The connection structure according to the present invention includes a first connection target member having at least one first electrode on its surface, a second connection target member having at least one second electrode on its surface, and the first connection target member, and a connecting portion connecting the second connection target member. In the connection structure according to the present invention, the material of the connection part is the above-mentioned conductive material, and the connection part is formed of the above-mentioned conductive material. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by a solder portion in the connection portion.

The manufacturing method of the connection structure includes the steps of using the above-described conductive material to dispose the conductive material on the surface of a first connection target member having at least one first electrode on the surface, and the above-described conductive material. A step of arranging a second connection target member having at least one second electrode on a surface opposite to the first connection target member side so that the first electrode and the second electrode face each other, and the conductivity By heating the conductive material above the melting point of the solder in the particles, a connection portion connecting the first connection target member and the second connection target member is formed by a cured product of the conductive material, further comprising: A step of electrically connecting the first electrode and the second electrode using a solder portion in the connection portion is provided. Preferably, the conductive material is heated above the curing temperature of the thermosetting component and thermosetting compound.

In the bonded structure and the manufacturing method of the bonded structure according to the present invention, since a specific conductive material is used, the solder in the plurality of conductive particles is likely to collect between the first electrode and the second electrode, and the solder is applied to the electrode (line). It can be placed efficiently on the table. Additionally, it is difficult for a part of the solder to be placed in the area (space) where the electrode is not formed, and the amount of solder placed in the area where the electrode is not formed can be significantly reduced. Accordingly, the reliability of conduction between the first electrode and the second electrode can be improved. In addition, electrical connection between horizontally adjacent electrodes that should not be connected can be prevented, and insulation reliability can be improved.

In addition, in order to efficiently arrange the solder in a plurality of conductive particles on the electrode and to significantly reduce the amount of solder placed in the area where the electrode is not formed, it is better to use a conductive paste rather than a conductive film. desirable.

The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, preferably 100 μm or less, and more preferably 80 μm or less. Solder wet area on the surface of the electrode (area in contact with solder out of 100% of the exposed area of the electrode, exposed area of the first electrode before forming the connection portion and the second electrode electrically connected to the first electrode) The area in contact with the solder portion after forming the connection portion (relative to 100%) is preferably 50% or more, more preferably 70% or more, and preferably 100% or less.

In the method of manufacturing a connected structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, no pressurization is performed, and the weight of the second connection target member is applied to the conductive material. Applying pressure, or applying pressure in at least one of the step of disposing the second connection target member and the step of forming the connection portion, and further, the step of disposing the second connection target member and the step of forming the connection portion. On both sides, it is preferable that the pressurizing pressure is less than 1 MPa. By not applying an applied pressure of 1 MPa or more, the aggregation of the solder in the conductive particles is significantly promoted. From the viewpoint of suppressing bending of the connection target member, in the method of manufacturing a connected structure according to the present invention, pressurization is performed in at least one of the step of arranging the second connection target member and the step of forming the connection portion, and , the pressing pressure may be less than 1 MPa in both the step of arranging the second connection target member and the step of forming the connection portion. When applying pressing, pressing may be performed only in the step of disposing the second connection target member, or pressing may be performed only in the step of forming the connection portion, or the second connection target member may be placed. Pressurization may be applied in both the step of forming the connection portion and the step of forming the connection portion. The case where the pressurization pressure is less than 1 MPa includes the case where no pressurization is applied. When pressurizing, the pressurizing pressure is preferably 0.9 MPa or less, more preferably 0.8 MPa or less. When the pressing pressure is 0.8 MPa or less, the aggregation of the solder in the conductive particles is promoted more significantly than when the pressing pressure exceeds 0.8 MPa.

In the method of manufacturing a connected structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, no pressurization is performed, and the weight of the second connection target member is applied to the conductive material. Preferably, in the step of arranging the second connection target member and the step of forming the connection portion, a pressing pressure exceeding the force of the weight of the second connection target member is not applied to the conductive material. It is desirable. In these cases, the uniformity of the solder amount in the plurality of solder portions can be further improved. In addition, the thickness of the solder portion can be increased more effectively, and it becomes easy for a large amount of solder from a plurality of conductive particles to collect between the electrodes, making it possible to more efficiently spread the solder from a plurality of conductive particles onto the electrode (line). It can be placed as . In addition, it is difficult for a portion of the solder in the plurality of conductive particles to be placed in the area (space) where the electrode is not formed, and the amount of solder in the conductive particles placed in the area where the electrode is not formed is further reduced. You can do less. Therefore, the reliability of conduction between electrodes can be further improved. In addition, electrical connection between electrodes adjacent to each other in the horizontal direction, which should not be connected, can be further prevented, and insulation reliability can be further improved.

Additionally, in the step of arranging the second connection target member and the step of forming the connection portion, if the weight of the second connection target member is applied to the conductive material without applying pressure, the electrode will form before the connection portion is formed. The solder placed in the unformed area (space) becomes more likely to gather between the first and second electrodes, and the solder in the plurality of conductive particles is placed on the electrode (line) more efficiently. The present inventors also found out what can be done. In the present invention, a combination of a configuration of using a conductive paste rather than a conductive film and a configuration of allowing the weight of the second connection target member to be applied to the conductive paste without applying pressure includes the following: It is of great significance because the effect of the invention can be achieved at a higher level.

In addition, WO2008/023452A1 describes that from the viewpoint of efficiently moving the solder powder to the electrode surface, applying pressure to a predetermined pressure during adhesion is used to more reliably form the solder area. From this point of view, it is described that the pressure is, for example, 0 MPa or more, preferably 1 MPa or more, and even if the pressure intentionally applied to the adhesive tape is 0 MPa, the self-weight of the member disposed on the adhesive tape causes a predetermined pressure to be applied to the adhesive tape. It is described that pressure may be applied. In WO2008/023452A1, it is described that the pressure intentionally applied to the adhesive tape may be 0 MPa, but the difference in effect between applying a pressure exceeding 0 MPa and 0 MPa is not described at all. Additionally, in WO2008/023452A1, there is no recognition at all about the importance of using a conductive paste in the form of a paste rather than a film.

Additionally, if a conductive paste is used instead of a conductive film, it becomes easy to adjust the thickness of the connection portion and the solder portion depending on the amount of conductive paste applied. On the other hand, with conductive films, there is a problem that in order to change or adjust the thickness of the connection portion, a conductive film with a different thickness must be prepared or a conductive film with a predetermined thickness must be prepared. Additionally, in the case of a conductive film, compared to a conductive paste, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder, and cohesion of the solder tends to be easily inhibited.

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

1 is a cross-sectional view schematically showing a bonded structure obtained 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 first connection target member 2 and a second connection target member 3. It is provided with a connecting portion (4) that is connected. The connection portion 4 is formed of the above-described electrically conductive material. In this embodiment, the electrically conductive material contains solder particles as electrically conductive particles.

The connection portion 4 has a solder portion 4A in which a plurality of solder particles are gathered and joined together, and a cured portion 4B in which a thermosetting component is thermoset. In this embodiment, solder particles are used as conductive particles to form the solder portion 4A. As for solder particles, both the center portion and the outer surface of the conductive portion are formed of solder.

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 by a 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. Additionally, in the connection portion 4, no solder is present in a region (cured portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a. In a region different from the solder portion 4A (cured portion 4B portion), there is no solder spaced apart from the solder portion 4A. Additionally, if the amount is small, solder may be present in a region (cured product portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a.

As shown in FIG. 1, in the connection structure 1, a plurality of solder particles gather between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the solder particles After the melt spreads the surface of the electrode and solidifies, the solder portion 4A is formed. For this reason, the connection areas between the solder portion 4A and the first electrode 2a and the solder portion 4A and the second electrode 3a increase. That is, by using solder particles, compared to the case of using conductive particles in which the outer surface portion of the conductive portion is a metal such as nickel, gold, or copper, the solder portion 4A, the first electrode 2a, and the solder portion 4A ) and the contact area between the second electrode 3a increases. For this reason, the conduction reliability and connection reliability in the connection structure 1 increase.

In addition, in the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in the opposing area between the first and second electrodes 2a and 3a. The connected structure 1X of the modified example shown in FIG. 3 is different from the connected structure 1 shown in FIG. 1 only in the connection portion 4X. The connection portion 4X has a solder portion 4XA and a hardened portion 4XB. Like the connection structure 1X, the majority of the solder portion 4XA is located in the area where the first and second electrodes 2a and 3a face each other, and a portion of the solder portion 4XA is located at the first and second electrodes. (2a, 3a) may protrude laterally from the opposing area. The solder portion 4XA protruding laterally from the area where the first and second electrodes 2a and 3a face each other is a part of the solder portion 4XA and is not solder spaced apart from the solder portion 4XA. . Additionally, in this embodiment, the amount of solder spaced apart from the solder portion can be reduced, but the solder spaced apart from the solder portion may be present in the cured portion.

If the amount of solder particles used is reduced, it becomes easier to obtain the connection structure 1. If the amount of solder particles used increases, it becomes easier to obtain the bonded structure 1X.

From the viewpoint of further improving conduction reliability, in the connection structures 1 and 1 When looking at the opposing parts of the two electrodes 3a, 50% or more (more preferably 60% or more, more preferably 60% or more) of 100% of the area of the opposing parts of the first electrode 2a and the second electrode 3a. It is preferable that the solder portions 4A and 4XA of the connecting portions 4 and 4X are disposed at least 70%, particularly preferably at least 80%, and most preferably at least 90%.

From the viewpoint of further improving conduction reliability, when viewing the opposing portions of the first electrode and the second electrode in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode 50% or more (more preferably 60% or more, further preferably 70% or more, particularly preferably 80% or more, most preferably 90% or more) of 100% of the area of the opposing portions of the two electrodes, It is preferable that the solder portion in the connection portion is disposed.

From the viewpoint of further improving conduction reliability, when the opposing portions of the first electrode and the second electrode are viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode At least 60% (more preferably at least 70%, even more preferably at least 80%, even more preferably at least 90%, particularly preferably at least 90%) of the solder portion of the connection portion at the portion where the electrode and the second electrode face each other. It is preferable that it is arranged at least 95%, most preferably at least 99%.

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

First, the first connection target member 2 having the first electrode 2a on its surface (upper surface) is prepared. Next, as shown in FIG. 2(a), on the surface of the first connection target member 2, a conductive material containing a thermosetting component 11B, a plurality of solder particles 11A, and a specific flux is applied. Place (11) (first process). The electrically-conductive material used is a thermosetting component (11B) and contains a thermosetting compound and a thermosetting agent.

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

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

Additionally, a second connection target member 3 having the second electrode 3a on its surface (lower surface) is prepared. Next, as shown in FIG. 2(b), in the conductive material 11 on the surface of the first connection target member 2, the first connection target member 2 side of the conductive material 11 is The second connection target member 3 is disposed on the opposite surface (second process). The second connection target member 3 is disposed on the surface of the conductive material 11 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 to the melting point or higher of the solder particles 11A (third process). Preferably, the conductive material 11 is heated above the curing temperature of the thermosetting component 11B (binder). During this heating, the solder particles 11A existing in the area where the electrode is not formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). When a conductive paste is used instead of a conductive film, solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. Additionally, the solder particles 11A are melted and joined to each other. Additionally, the thermosetting component (11B) is thermoset. As a result, as shown in Fig. 2(c), the connection portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed with the conductive material 11. do. The connection portion 4 is formed by the conductive material 11, the solder portion 4A is formed by joining the plurality of solder particles 11A, and the thermosetting component 11B is heat-cured to form the cured portion 4B. is formed When the solder particles 11A move sufficiently, the solder particles 11A that are not located between the first electrode 2a and the second electrode 3a begin to move, and then the first electrode 2a and the second electrode 3a begin to move. It is not necessary to keep the temperature constant until the movement of the solder particles 11A is completed between (3a).

In this embodiment, it is preferable not to apply pressure in the second process and the third process. In this case, the weight of the second connection target member 3 is applied to the conductive material 11. Because of this, when forming the connecting portion 4, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. Additionally, in at least one of the second process and the third process, when pressure is applied, the tendency for solder particles to gather between the first electrode and the second electrode increases.

Furthermore, in this embodiment, since pressurization is not performed, when the second connection target member is superimposed on the first connection target member coated with a conductive material, the electrode of the first connection target member and the second connection target member Even when the first connection target member and the second connection target member overlap in a state where the electrode alignment is misaligned, the misalignment can be corrected to connect the electrode of the first connection target member and the electrode of the second connection target member. (self-alignment effect). This means that the molten solder that has self-agglomerated between the electrode of the first connection target member and the electrode of the second connection target member is the solder between the electrode of the first connection target member and the electrode of the second connection target member and other conductive materials. This is because the area in which the components are in contact with the smallest is energetically stable, so the force acting on the connection structure with alignment, which is the connection structure that has the minimum area, acts. At this time, it is preferable that the conductive material is not cured and that the viscosity of components other than the conductive particles of the conductive material are sufficiently low at the temperature and time.

In this way, the connection structure 1 shown in FIG. 1 is obtained. Additionally, the second process and the third process may be performed continuously. Furthermore, after performing the second step, the resulting laminate of the first connection target member 2, the conductive material 11, and the second connection target member 3 is moved to a heating unit, and the third step is performed. You can do it. In order to perform the heating, the laminate may be placed on a heating member, or the laminate may be placed in a heated space.

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

As a heating method in the third step, a method of heating the entire connected structure to a temperature higher than the melting point of the solder and the curing temperature of the thermosetting compound using a reflow furnace or an oven, or a method of heating only the connection portion of the connected structure locally One possible method is heating.

Equipment used in the local heating method includes a hot plate, a heat gun that applies hot air, a soldering iron, and an infrared heater.

Additionally, when heating locally with a hot plate, the upper surface of the hot plate should be made of a metal with high thermal conductivity just below the joint, and other areas where heating is not desirable should be made of a material with low thermal conductivity such as fluororesin. It is desirable to form

The first and second connection target members are not particularly limited. The first and second connection target members specifically include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, condensers and diodes, and resin films, printed boards, flexible printed boards, and flexible flat cables, Electronic components such as circuit boards such as rigid flexible substrates, glass epoxy substrates, and glass substrates can be mentioned. It is preferable that the first and second connection target members are electronic components.

It is preferable that at least one of the first connection target member and the second connection target member is a semiconductor chip, a resin film, a flexible printed circuit board, a rigid flexible substrate, or a flexible flat cable, and the resin film, a flexible printed circuit board, or a flexible flat cable Alternatively, it is more preferable that it is a rigid flexible substrate. The second connection target member is preferably a semiconductor chip, a resin film, a flexible printed board, a rigid flexible board, or a flexible flat cable, and more preferably a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. Resin films, flexible printed boards, flexible flat cables, and rigid flexible boards have the properties of being highly flexible and relatively lightweight. When a conductive film is used to connect such connection target members, the solder in the conductive particles tends to be difficult to collect on the electrode. In contrast, by using a conductive paste, even if a resin film, flexible printed board, flexible flat cable, or rigid flexible board is used, the conduction reliability between electrodes can be sufficiently increased by efficiently collecting the solder in the conductive particles onto the electrodes. there is. When using a resin film, flexible printed board, flexible flat cable, or rigid flexible board, the effect of improving the conduction reliability between electrodes by not applying pressure is greater than when using other connection target members such as semiconductor chips. obtained effectively.

The types of connection target members include peripheral devices and area arrays. As a characteristic of each member, in the peripheral device substrate, electrodes exist only on the outer periphery of the substrate. In an area array substrate, electrodes exist within the surface.

Examples of electrodes provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the connection target member is a flexible printed circuit board, the electrode is preferably a gold electrode, nickel electrode, tin electrode, silver electrode, or 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. In addition, when the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material for 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 elements include Sn, Al, and Ga.

Hereinafter, the present invention will be described in detail through examples and comparative examples. The present invention is not limited to the following examples.

Thermosetting compound 1: Resorcinol type epoxy compound, “Epolite TDC-LC” manufactured by Kyoesia Chemical, epoxy equivalent weight 120 g/eq

Thermosetting compound 2: Highly reactive epoxy compound, “EP-3300S” manufactured by ADEKA Corporation, epoxy equivalent weight 165 g/eq

Heat curing agent 1: Trimethylolpropane tris (3-mercaptopropionate), “TMMP” manufactured by SC Yuki Chemical Co., Ltd.

Heat curing agent 2: Dipentaerythritol hexakis (3-mercaptopropionate), “DPMP” manufactured by SC Yuki Chemical Co., Ltd.

Latent epoxy thermosetting agent 1: “Fujicure 7000” manufactured by T&K TOKA.

Preparation method for Flux 1:

In a three-necked flask, 160 g of acetone and 32 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and dissolved at room temperature until uniform. After that, 26 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 30 minutes, and after the dropwise addition was completed, the mixture was stirred at room temperature for 2 hours. The precipitated white crystals were collected by filtration, washed with acetone, and vacuum dried to obtain Flux 1. The average particle diameter was measured with 50 arbitrary particles using a scanning electron microscope (“S-4300SEN” manufactured by Hitachi Seisakusho Co., Ltd.), and the average value was calculated. Additionally, the melting point was determined by measuring the endothermic peak using DSC (“DSC6200” manufactured by Seiko Instruments).

Preparation method of Flux 2:

The white crystals obtained in the same manner as Flux 1 were ground in a mortar until the average particle diameter reached 10 μm, and Flux 2 was obtained.

Preparation method of Flux 3:

The white crystals obtained in the same manner as Flux 1 were ground in a mortar until the average particle diameter reached 1 μm, and Flux 3 was obtained.

Preparation method of Flux 4:

The white crystals obtained in the same manner as Flux 1 were ground in a mortar until the average particle diameter reached 0.05 μm, and Flux 4 was obtained.

Preparation method of Flux 5:

In a three-necked flask, 160 g of acetone and 31 g of cyclohexanecarboxylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and dissolved at room temperature until uniform. After that, 24 g of cyclohexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 30 minutes, and the mixture was stirred at room temperature for 2 hours after the dropwise addition was completed. The precipitated white crystals were collected by filtration, washed with acetone, and dried under vacuum. After that, it was pulverized in a mortar until the average particle diameter reached 10 μm, and flux 5 was obtained.

Preparation method of Flux 6:

In a three-neck flask, 160 g of acetone and 35 g of adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and dissolved at room temperature until uniform. After that, 26 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 30 minutes, and after the dropwise addition was completed, the mixture was stirred at room temperature for 2 hours. The precipitated white crystals were collected by filtration, washed with acetone, and dried under vacuum. After that, it was pulverized in a mortar until the average particle diameter reached 10 μm, and flux 6 was obtained.

Preparation method of Flux 7:

In a three-neck flask, 26.8 g of triethanolamine was added to 12.6 g of citric acid monohydrate, and the citric acid was dissolved while stirring in an oil bath at 120°C. The obtained triethanolamine citric acid salt was liquid at 25°C.

How to make Flux 8:

In a three-neck flask, 37.25 g of triethanolamine was added to 35.0 g of glutaric acid, and the glutaric acid was dissolved while stirring in an oil bath at 120°C. The obtained triethanolamine glutaric acid salt was semi-solid at 25°C.

Additionally, for the solid flux at 25°C, the average particle diameter of the flux was the same as that of the flux alone before being mixed with the conductive particles and thermosetting components, and the flux in the conductive material after being mixed with the conductive particles and thermosetting components.

Solder particle 1 (SnBi solder particle, melting point 139°C, “DS-10” manufactured by Mitsui Kinzoku Corporation, average particle diameter (median diameter 12 μm))

Solder particle 2 (SAC solder particle, melting point 217°C, “DS-10” manufactured by Mitsui Kinzoku Corporation, average particle diameter (median diameter 12 μm))

Manufacturing method of solder particles 3:

In a three-necked flask, 160 g of acetone and 32 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and dissolved at room temperature until uniform. After that, 100 g of solder particles 1 were added and stirred for 15 minutes, then 26 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 30 minutes and stirred at room temperature for 2 hours after the dropwise addition was completed to apply flux to the surface of the solder particles. It was precipitated. After that, the solder particles were washed once with acetone and dried under vacuum to obtain solder particles 3.

(Examples 1 to 17 and Comparative Examples 1 to 2)

(1) Preparation of anisotropic conductive paste

The components shown in Tables 1 and 2 below were mixed in the amounts shown in Tables 1 and 2 below to obtain an anisotropic electrically conductive paste. In the obtained anisotropic electrically conductive paste, the flux existed in the state shown in Tables 1 and 2.

(2) Manufacturing of connection structure (area array)

As the first connection target member, a semiconductor chip was prepared in which copper electrodes with a diameter of 250 μm and a thickness of 10 μm were arranged in an area array at a pitch of 400 μm on the surface of the semiconductor chip main body (size 5 × 5 mm, thickness 0.4 mm). did. The number of copper electrodes per semiconductor chip is 10 x 10, a total of 100.

As the second connection target member, a gold electrode is disposed on the surface of the glass epoxy substrate main body (size 20 x 20 mm, thickness 1.2 mm, material FR-4) so as to have the same pattern as that of the electrode of the first connection target member, , a glass epoxy substrate was prepared with a solder resist film formed in the area where the gold electrode was not placed. The level difference between the surface of the copper electrode and the surface of the solder resist film is 15 μm, and the solder resist film protrudes beyond the copper electrode.

An anisotropic conductive paste immediately after manufacture was applied to the upper surface of the glass epoxy substrate to a thickness of 50 μm to form an anisotropic conductive paste layer. After leaving for 2 hours at 23°C 50% RH, a semiconductor chip was laminated on the upper surface of the anisotropic conductive paste layer with the electrodes facing each other. The weight of the semiconductor chip is applied to the anisotropic conductive paste layer. From that state, the temperature of the anisotropic conductive paste layer was the melting point of the solder 5 seconds after the start of the temperature increase (139°C in Examples 1 to 9, 12 to 17 and Comparative Examples 1 and 2, and 217°C in Examples 10 and 11). ) was heated to In addition, 15 seconds after the start of the temperature increase, the temperature of the anisotropic conductive paste layer was the melting point of the solder + 21°C (160°C in Examples 1 to 9, 12 to 17 and Comparative Examples 1 and 2, and 238°C in Examples 10 and 11). °C) and maintained for 5 minutes to cure the anisotropic conductive paste layer, thereby obtaining a bonded structure. During heating, no pressurization was performed.

(evaluation)

(1) Viscosity

The viscosity (η25) of the anisotropic conductive paste at 25°C was measured using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) under conditions of 25°C and 5 rpm.

(2) Storage stability

The anisotropic conductive paste was placed in a syringe and stored at 23°C for 24 hours. After storage, the viscosity (η25) of the anisotropic conductive paste at 25°C was measured using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) under conditions of 25°C and 5 rpm. Storage stability was determined based on the following criteria.

[Judgement criteria for storage stability]

○○: Viscosity after storage is within ±25% of the viscosity before storage

○: Does not correspond to the standards for ○○, and the viscosity after storage is within ±50% of the viscosity before storage.

△: Does not correspond to the standards of ○○ and ○, and the viscosity after storage is within ±75% of the viscosity before storage.

×: Does not correspond to the standards of ○○, ○ and △

(3) Thickness of solder part

The thickness of the solder portion located between the upper and lower electrodes was evaluated by cross-sectional observation of the obtained connection structure.

(4) Placement precision of solder on electrode 1

In the obtained connection structure, when the portions of the first electrode and the second electrode are viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the area of the portions of the first electrode and the second electrode that face each other is 100 The ratio The placement accuracy 1 of the solder on the electrode was determined based on the following standards.

[Judgment criteria for placement accuracy 1 of solder on electrode]

○○: Ratio

○: Ratio X is 60% or more and less than 70%

△: Ratio X is 50% or more and less than 60%

×: Ratio X is less than 50%

(5) Solder placement accuracy 2 on the electrode

In the obtained connection structure, when the portions of the first electrode and the second electrode facing each other are viewed in a direction perpendicular to the lamination direction of the first electrode, the connection section, and the second electrode, the first electrode is 100% of the solder portion in the connection section. The ratio Y of the solder portion in the connection portion disposed in the opposing portions of the and second electrodes was evaluated. The placement accuracy 2 of the solder on the electrode was determined based on the following standards.

[Judgment criteria for placement accuracy 2 of solder on electrode]

○○: Ratio Y is 99% or more

○: Ratio Y is 90% or more and less than 99%

△: Ratio Y is 70% or more and less than 90%

×: Ratio Y is less than 70%

(6) Conduction reliability between upper and lower electrodes

In the obtained connected structures (n=15 pieces), the connection resistance per connection point between the upper and lower electrodes was measured using the four-terminal method. The average value of the connection resistance was calculated. Additionally, from the relationship of voltage = current x resistance, the connection resistance can be obtained by measuring the voltage when a constant current is passed. Continuity reliability was determined based on the following criteria. However, in the case where the upper and lower electrodes were not conducting at least one out of n = 15, it was determined as “×”.

[Judgement criteria for continuity reliability]

○○: The average value of connection resistance is 50mΩ or less.

○: The average value of connection resistance exceeds 50mΩ and is 70mΩ or less.

△: Average value of connection resistance exceeds 70mΩ and is less than 100mΩ

×: The average value of the connection resistance exceeds 100 mΩ, or a connection defect has occurred.

(7) Insulation reliability between horizontally adjacent electrodes

In the obtained bonded structure (n = 15 pieces), after being left in an atmosphere of 85°C and 85% humidity for 100 hours, 15 V was applied between horizontally adjacent electrodes, and the resistance value was measured at 25 locations. Insulation reliability was determined based on the following criteria. However, if even one of n = 15 electrodes adjacent to each other in the horizontal direction were conducting, it was determined as “×”.

[Judgment criteria for insulation reliability]

○○○: The average value of connection resistance is 10 ¹⁴ Ω or more.

○○: Average value of connection resistance is 10 ⁸ Ω or more but less than 10 ¹⁴ Ω

○: The average value of connection resistance is 10 ⁶ Ω or more and less than 10 ⁸ Ω.

△: Average value of connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω

×: Average value of connection resistance is less than 10 ⁵ Ω

Details and results are shown in Tables 1 and 2 below.

1, 1X… connection structure
2… Absence of first connection target
2a… first electrode
3… Absence of second connection target
3a… second electrode
4, 4X… connection
4A, 4XA… solder
4B, 4XB… Hard cargo department
11… challenge 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… 2nd challenge
33B… solder
41… conductive particles
42… solder

Claims (14)

A plurality of conductive particles having solder on the outer surface portion of the conductive portion,
thermosetting ingredients,
Contains flux,
The flux is a salt of an organic compound having a carboxyl group and an organic compound having an amino group,
The organic compound having the amino group is an aromatic amine compound or an aliphatic alicyclic amine compound,
In a conductive material at 25°C, the flux exists as a solid,
A conductive material wherein the flux has an average particle diameter of 0.1 μm or more and 30 μm or less. The electrically conductive material according to claim 1, wherein the flux alone is solid at 25°C when not mixed with the electrically conductive particles and the thermosetting component. The conductive material according to claim 1 or 2, wherein a ratio of the average particle diameter of the flux to the average particle diameter of the conductive particles is 3 or less. The electrically conductive material according to claim 1 or 2, wherein the flux has a melting point of -50°C or higher and the melting point of the solder in the conductive particles +50°C or lower. The electrically conductive material according to claim 1 or 2, wherein the electrically conductive particles are solder particles. The electrically-conductive material according to claim 1 or 2, wherein the thermosetting component contains a thermosetting compound having a triazine skeleton. The electrically conductive material according to claim 1 or 2, wherein the flux is adhered on the surface of the electrically conductive particles. The electrically-conductive material of Claim 1 or 2 whose average particle diameter of the said electroconductive particle is 1 micrometer or more and 40 micrometers or less. The electrically conductive material according to claim 1 or 2, wherein the content of the conductive particles is 10% by weight or more and 90% by weight or less in 100% by weight of the electrically conductive material. The electrically conductive material according to claim 1 or 2, which is a conductive paste. A first connection target member having at least one first electrode on its surface,
a second connection target member having at least one second electrode on its surface;
It has a connection part connecting the first connection target member and the second connection target member,
The material of the connection part is the conductive material according to claim 1 or 2,
A connection structure in which the first electrode and the second electrode are electrically connected by a solder portion in the connection portion. The method of claim 11, wherein when the opposing portions of the first electrode and the second electrode are viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode are A connection structure in which a solder portion of the connection portion is disposed in 50% or more of 100% of the area of the portions facing each other. delete delete

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