JP6966322B2 - Conductive materials and connection structures - Google Patents

Description

The present invention relates to a conductive material containing conductive particles having solder. The present invention also relates to a connection structure using the above conductive material.

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

In order to obtain various connection structures, the anisotropic conductive material may be used, for example, for connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), or connection between a semiconductor chip and a flexible printed circuit board (COF (COF). It is used for 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)).

With the anisotropic conductive material, for example, when the electrode of the flexible printed substrate and the electrode of the glass epoxy substrate are electrically connected, the anisotropic conductive material containing the conductive particles is arranged on the glass epoxy substrate. do. Next, the flexible printed substrates are laminated, heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected to each other via the conductive particles to obtain a connection structure.

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 is not completed at the melting point of the conductive particles. Specific examples of the conductive particles include tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd). ), Metals such as gallium (Ga) and thallium (Tl), and alloys of these metals are mentioned.

In Patent Document 1, a resin heating step for heating an anisotropic conductive resin to a temperature higher than the melting point of the conductive particles and the curing of the resin component is not completed, and a resin component curing step for curing the resin component. It is described that the electrodes are electrically connected through the above. Further, Patent Document 1 describes that the mounting is performed with the temperature profile shown in FIG. 8 of Patent Document 1. In Patent Document 1, the conductive particles are melted in the resin component whose curing is not completed at the temperature at which the anisotropic conductive resin is heated.

Patent Document 2 below discloses an adhesive tape containing a resin layer containing a thermosetting resin, solder powder, and a curing agent, in which the solder powder and the curing agent are present in the resin layer. There is. This adhesive tape is in the form of a film, not in the form of 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 carboxylic acid anhydride and diethanolamines or triethanolamines. Reactants are listed.

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

Conventional solder powder and anisotropic conductive paste containing conductive particles having a solder layer on the surface may have low storage stability. Further, in the conventional anisotropic conductive paste, when the conductive material is placed on the connection target member at the time of connection between the electrodes and then left for a long time, it may be difficult for the solder to aggregate on the electrodes. As a result, continuity reliability tends to be low.

An object of the present invention is a conductive material capable of exhibiting high conduction reliability because it has high storage stability and exhibits excellent solder cohesiveness even when the conductive material is placed on a member to be connected and then left for a long time. Is to provide. Another object of the present invention is to provide a connection structure using the above conductive material.

According to a broad aspect of the present invention, the outer surface portion of the conductive portion contains a plurality of conductive particles having solder, a thermosetting component, and a flux, and the flux is a salt of an acid and a base. , A conductive material in which the flux is present as a solid at 25 ° C. in a conductive material at 25 ° C. is provided.

In a particular aspect of the conductive material according to the present invention, the flux alone is solid at 25 ° C. without being mixed with the conductive particles and the thermosetting component.

In certain aspects 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 size of the flux is 30 μm or less in the conductive material at 25 ° C.

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

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

In certain aspects of the conductive material according to the present invention, the conductive particles are solder particles.

In certain aspects of the conductive material according to the present invention, the thermosetting component comprises a thermosetting compound having a triazine skeleton.

In certain aspects of the conductive material according to the present invention, the flux adheres to the surface of the conductive particles.

In a specific aspect of the conductive material according to the present invention, the average particle size of the conductive particles is 1 μm or more and 40 μm or less.

In a specific aspect of the conductive material according to the present invention, the content of the conductive particles is 10% by weight or more and 90% by weight or less in 100% by weight of the conductive material.

In certain aspects of the conductive material according to the present invention, the conductive material is a conductive paste.

According to a broad aspect of the present invention, a first connection target member having at least one first electrode on the surface, a second connection target member having at least one second electrode on the surface, and the first connection target member. The connection target member and the connection portion connecting the second connection target member are provided, and the material of the connection portion is the above-mentioned conductive material, and the first electrode and the second electrode are used. Provided is a connection structure in which is electrically connected by a solder portion in the connection portion.

In a specific aspect of the connection structure according to the present invention, the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode. When looking at the portion, the solder portion in the connection portion is arranged in 50% or more of the area of 100% of the portion where the first electrode and the second electrode face each other.

The conductive material according to the present invention contains a plurality of conductive particles having solder, a thermosetting component, and a flux on the outer surface portion of the conductive portion, and the flux is a salt of an acid and a base. Since the flux exists as a solid in the conductive material at 25 ° C., the storage stability of the conductive material can be improved, and even if the conductive material is left on the connecting target member for a long time after being arranged. Since it exhibits excellent solder cohesiveness, high conduction reliability can be exhibited.

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

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

(Conductive material)
The conductive material according to the present invention includes a plurality of conductive particles and a binder. The conductive particles have a conductive portion. The conductive particles have solder on the outer surface portion of the conductive portion. Solder is contained in the conductive portion and is a part or all of the conductive portion. The binder is a component excluding conductive particles contained in the conductive material.

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

Whether or not the flux is a solid in a conductive material at 25 ° C. can be determined as follows. In the present specification, with respect to a flux that is not liquid at 25 ° C, a flux that retains its shape when a conductive material containing a flux is allowed to stand at 25 ° C for 5 minutes is defined as a solid flux at 25 ° C, and is defined as a solid flux at 25 ° C. A flux that does not retain its shape when the conductive material containing the flux is allowed to stand for 5 minutes is defined as a semi-solid flux at 25 ° C. Further, the flux that is semi-solid at 25 ° C. is not included in the flux that is solid at 25 ° C.

In the present invention, since the above configuration is provided, the storage stability of the conductive material can be improved. Further, in the present invention, since the above-mentioned configuration is provided, excellent solder cohesiveness is exhibited even if the conductive material is placed on the connecting target member and then left for a long time, so that high conduction reliability can be achieved. Can be expressed.

In the present invention, it is preferable that the flux alone is a solid at 25 ° C. without being 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 allow the flux to exist as a solid in a conductive material at 25 ° C.

Whether or not the flux alone is solid at 25 ° C. can be determined as follows. In the present specification, with respect to a flux that is not liquid at 25 ° C, a flux that retains its shape when the flux alone is allowed to stand at 25 ° C for 5 minutes is defined as a solid flux at 25 ° C, and the flux alone is defined as a flux at 25 ° C. A flux that does not retain its shape when left to stand for 5 minutes is defined as a semi-solid flux at 25 ° C. Further, the flux that is semi-solid at 25 ° C. is not included in the flux that is solid at 25 ° C.

When obtaining the connection structure, after the conductive material is placed on the first connection target member, the laminate of the first connection target member and the conductive material forms the second connection target member on the conductive material. May be temporarily stored before placement. In the present invention, even if the laminated body is stored, a connection structure having excellent conduction reliability can be obtained.

Further, in the present invention, since the above configuration is provided, the solder in the conductive particles can be efficiently arranged 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, but in the present invention, even if the electrode width is narrow, the solder can be sufficiently collected on the electrode. In the present invention, since the above configuration is provided, when the electrodes are electrically connected, the solder in the conductive particles is likely to be located between the upper and lower facing electrodes, and the solder in the conductive particles is placed in the electrodes. It can be efficiently placed on the (line). Further, in the present invention, when the electrode width is wide, the solder in the conductive particles is arranged more efficiently on the electrode.

Further, it is difficult for a part of the solder in the conductive particles to be arranged in the region (space) where the electrode is not formed, and the amount of the solder arranged in the region where the electrode is not formed can be considerably reduced. In the present invention, solder that is not located between the facing electrodes can be efficiently moved between the facing electrodes. Therefore, the continuity reliability between the electrodes can be improved. Moreover, it is possible to prevent electrical connection between horizontally adjacent electrodes that should not be connected, and it is possible to improve insulation reliability.

Further, in the present invention, the heat resistance of the cured product of the conductive material can be enhanced. In particular, when a conductive material is used in an optical semiconductor device, heat is generated during light irradiation, and the cured product of the conductive material is exposed to a high temperature. Since the conductive material according to the present invention has excellent heat resistance of the cured product, it can be suitably used for 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 becomes high.

Further, in the present invention, it is possible to prevent the positional deviation between the electrodes. In the present invention, when the second connection target member is superposed on the first connection target member on which the conductive material is arranged on the upper surface, the electrodes of the first connection target member and the electrodes of the second connection target member are used. Even if the first connection target member and the second connection target member are overlapped with each other in a state where the alignment of the first connection target member is misaligned, the misalignment is corrected and the electrode of the first connection target member and the second connection target member are overlapped. It can be connected to the electrodes of the member (self-alignment effect).

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

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

The conductive material can be used as a conductive paste, a conductive film, or the like. The conductive film is preferably an anisotropic conductive film. From the viewpoint of more efficiently arranging the solder in the conductive particles on the electrode, the conductive material is preferably a conductive paste. The conductive material is suitably used for electrical connection of electrodes. The conductive material is preferably a circuit connection material.

Hereinafter, each component contained in the conductive material will be described. In the present specification, "(meth) acrylate" means one or both of "acrylate" and "methacrylate", and "(meth) acrylic" means one or both of "acrylic" and "methacrylic". Meaning, "(meth) acryloyl" means one or both of "acryloyl" and "methacrylic".

(Conductive particles)
The conductive particles electrically connect between the electrodes of the member to be connected. The conductive particles have solder on the outer surface portion of the conductive portion. The conductive particles may be solder particles formed by soldering. The solder particles have solder on the outer surface portion of the conductive portion. In the solder particles, both the central portion and the outer surface portion of the conductive portion are formed of solder. The solder particles are particles in which both the central portion and the conductive outer surface are solder. The solder particles do not have base particles as core particles. The solder particles are different from the conductive particles having the base particles and the conductive portions arranged on the surface of the base particles. The solder particles contain, for example, solder in an amount of preferably 80% by weight or more, more preferably 90% by weight or more, still more preferably 95% by weight or more. The conductive particles may have a base material particles and a conductive portion arranged on the surface of the base material particles. In this case, the conductive particles have solder on the outer surface portion of the conductive portion.

Compared with the case where the above-mentioned solder particles are used, when the conductive particles having the base particles not formed by the solder and the solder portion arranged on the surface of the base particles are used, they are on the electrode. Since the conductive particles are less likely to collect and the solder bondability between the conductive particles is low, the conductive particles that have moved on the electrodes tend to move easily to the outside of the electrodes, and the effect of suppressing the displacement between the electrodes is suppressed. Also tends to be low. Therefore, the conductive particles are preferably solder particles formed by soldering.

From the viewpoint of effectively lowering the connection resistance in the connection structure and effectively suppressing the generation of voids, the outer surface of the conductive particles (outer surface of the solder) has a carboxyl group or an amino group. Is preferable, a carboxyl group is preferably present, and an amino group is preferably present. A group containing a carboxyl group or an amino group is shared on the outer surface of the conductive particles (outer surface of the solder) via a Si—O bond, an ether bond, an ester bond or a group represented by the following formula (X). It is preferable that they are bonded. The group containing a carboxyl group or an amino group may contain both a carboxyl group and an amino group. In the following formula (X), the right end portion and the left end portion represent a binding site.

Hydroxyl groups are present on the surface of the solder. By covalently bonding this hydroxyl group and a group containing a carboxyl group, a stronger bond can be formed than in the case of bonding by another coordination bond (chelate coordination) or the like, so that the connection resistance between the electrodes is lowered. Moreover, conductive particles capable of suppressing the generation of voids can be obtained.

In the above conductive particles, the bonding form between the surface of the solder and the group containing a carboxyl group may not include a coordination bond, or may not include a bond due to a 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 functional group capable of reacting with a hydroxyl group and a carboxyl group or an amino group (from the viewpoint of effectively suppressing the generation of voids. Hereinafter, it may be referred to as compound X), and it is preferably obtained by reacting a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group. In the above reaction, a covalent bond is formed. By reacting the hydroxyl group on the surface of the solder with the functional group capable of reacting with the hydroxyl group in the compound X, it is possible to easily obtain solder particles in which a group containing a carboxyl group or an amino group is covalently bonded to the surface of the solder. It is also possible to obtain solder particles in which a group containing a carboxyl group or an amino group is covalently bonded to the surface of the solder via an ether bond or an ester bond. By reacting the hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group, the compound X can be chemically bonded to the surface of the solder in the form of a covalent bond.

Examples of the functional group capable of reacting with the hydroxyl group include a hydroxyl group, a carboxyl group, an ester group and a carbonyl group. A hydroxyl group or a carboxyl group is preferable. 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, 4-. Aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyl acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutylic acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, bacsenic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedic acid, dodecanedic acid and the like. Be done. Glutaric acid or glycolic acid is preferred. As the compound having a functional group capable of reacting with the hydroxyl group, only one kind may be used, or two or more kinds 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 X preferably has a flux action, and the compound X preferably has a flux action in a state of being bonded to the surface of the solder. The compound having a flux action can remove the oxide film on the surface of the solder and the oxide film on the surface of the electrode. The carboxyl group has a flux action.

Compounds having a flux action include levulinic acid, glutaric acid, glycolic acid, adipic acid, succinic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyl acid. , 3-Methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyl acid, 4-phenylbutyric acid and the like. Glutaric acid, adipic acid or glycolic acid are preferred. Only one kind of the above-mentioned compound having a flux action may be used, or two or more kinds may be used in combination.

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

The method for producing conductive particles includes, for example, a step of mixing the conductive particles, a compound having a functional group capable of reacting with a hydroxyl group and a carboxyl group, a catalyst, and a solvent using the conductive particles. 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 by the mixing step.

Further, in the method for producing conductive particles, the conductive particles are mixed with 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 heated. Is preferable. By the mixing and heating steps, conductive particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be obtained more easily.

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, more preferably toluene. As the solvent, only one kind may be used, or two or more kinds may be used in combination.

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

It is preferable to heat at the time of the above 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 above-mentioned conductive particles use an isocyanate compound and react the above-mentioned isocyanate compound with the hydroxyl group on the surface of the solder. It is preferable that it is obtained through a step of making it. In the above reaction, a covalent bond is formed. By reacting the hydroxyl group on the surface of the solder with the 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 surface of the solder, a group derived from the isocyanate group can be chemically bonded to the surface of the solder in the form of a covalent bond.

Further, the silane coupling agent can be easily reacted with the group derived from the isocyanate group. Since the conductive particles can be easily obtained, the group containing the carboxyl group is introduced by the reaction using the silane coupling agent having a carboxyl group, or the reaction using the silane coupling agent. Later, it is preferably introduced by reacting a group derived from a silane coupling agent with a compound having at least one carboxyl group. The conductive particles are preferably obtained by reacting the hydroxyl group on the surface of the solder with the isocyanate compound using the isocyanate compound, and then reacting the compound having at least one carboxyl group.

From the viewpoint of effectively lowering the connection resistance in the connection 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, the residual isocyanate group and the compound having reactivity with the residual isocyanate group and having a carboxyl group are reacted, so that the surface of the solder is represented by the formula (X). A carboxyl group can be introduced via the group to be added.

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

Examples of the silane coupling agent include 3-isocyanatepropyltriethoxysilane (“KBE-9007” manufactured by Shinetsu Silicone Co., Ltd.) and 3-isocyanatepropyltrimethoxysilane (“Y-5187” manufactured by MOMENTIVE). Only one kind of the silane coupling agent may be used, or two or more kinds thereof may be used in combination.

Examples of the compound 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 and 4-amino. Buty acid, 3-mercaptopropionic acid, 3-mercaptoisobutyl acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutylic acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecane Acids, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, baxenoic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedic acid, dodecanedic acid and the like. .. Glutaric acid, adipic acid or glycolic acid are preferred. As the compound having at least one carboxyl group, only one kind may be used, or two or more kinds may be used in combination.

After reacting the isocyanate compound with the hydroxyl group on the surface of the solder using the isocyanate compound, the carboxyl group of a part of the compound having a plurality of carboxyl groups is reacted with the hydroxyl group on the surface of the solder to form a carboxyl group. Groups containing the above can be retained.

In the method for producing conductive particles, the isocyanate compound is reacted with the hydroxyl group on the surface of the solder by using the conductive particles and the isocyanate compound, and then the compound having at least one carboxyl group is reacted. Then, conductive particles having a group containing a carboxyl group bonded to the surface of the solder via a group represented by the above formula (X) are obtained. In the above-mentioned method for producing conductive particles, conductive particles in which a group containing a carboxyl group is introduced on the surface of the solder can be easily obtained by the above-mentioned steps.

Specific examples of the method for producing the 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. Then, a silane coupling agent is covalently bonded to the surface of the solder by using a reaction catalyst of a hydroxyl group and an isocyanate group on the surface of the solder of the conductive particles. Next, a hydroxyl group is generated by hydrolyzing the alkoxy group bonded to the silicon atom of the silane coupling agent. The generated hydroxyl group is reacted with the carboxyl group of the compound having at least one carboxyl group.

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

As reaction catalysts of hydroxyl groups and isocyanate groups on the solder surface of conductive particles, tin-based catalysts (dibutyltin dilaurate, etc.), amine-based catalysts (triethylenediamine, etc.), carboxylate catalysts (lead naphthenate, potassium acetate, etc.) , And a trialkylphosphine catalyst (triethylphosphine, etc.) and the like.

From the viewpoint of effectively lowering the connection resistance in the connection structure and effectively suppressing the generation of voids, the compound having at least one carboxyl group is a compound represented by the following formula (1). Is preferable. The compound represented by the following formula (1) has a flux action. Further, the compound represented by the following formula (1) has a flux action in a state of being 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 above 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. The R in the above formula (1A) is the same as the R in the above formula (1).

In the above formula (1B), R represents a divalent organic group having 1 to 5 carbon atoms. The R in the above formula (1B) is the same as the R in the above 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 the following formula (2A) and the following formula (2B), the left end portion represents a binding site.

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

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

From the viewpoint of enhancing the wettability of the surface of the solder, the molecular weight of the compound having at least one carboxyl group is preferably 10,000 or less, more preferably 1000 or less, still more preferably 500 or less. From the viewpoint of suppressing migration more effectively and further effectively lowering the connection resistance in the connection structure, the molecular weight of the compound having at least one carboxyl group is preferably 80 or more, more preferably. Is 100 or more, more preferably 120 or more.

The molecular weight means 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. When the compound having at least one carboxyl group is a polymer, it means the weight average molecular weight.

Since the cohesiveness of the conductive particles can be effectively enhanced at the time of conductive connection, the conductive particles may have a conductive particle main body and an anionic polymer arranged on the surface of the conductive particle main body. preferable. The conductive particles are preferably obtained by surface-treating the main body of the conductive particles with an anionic polymer or a compound to be an anionic polymer. The conductive particles are preferably a surface-treated product of an anionic polymer or a compound that becomes an anionic polymer. Only one kind of the anion polymer and the compound to be the anion polymer may be used, or two or more kinds may be used in combination. The anionic polymer is a polymer having an acidic group.

As a method of surface-treating the main body of the conductive particles with an anionic polymer, for example, as an anionic polymer, a (meth) acrylic polymer copolymerized with (meth) acrylic acid, which is synthesized from a dicarboxylic acid and a diol and has carboxyl groups at both ends. Polyester polymer having, polymer obtained by intermolecular dehydration condensation reaction of dicarboxylic acid and having carboxyl group at both ends, polyester polymer synthesized from dicarboxylic acid and diamine and having carboxyl group at both ends, and modification having carboxyl group A method of reacting the carboxyl group of the anionic polymer with the hydroxyl group on the surface of the conductive particle body by using Poval (“Gosenex T” manufactured by Nippon Synthetic Chemical Co., Ltd.) can be mentioned.

Examples of the anionic moiety of the anionic polymer include the carboxyl group, and other than that, a tosyl group (p-H ₃ CC ₆ H ₄ S (= O) _2- ) and a sulfonic acid ion group (-SO ₃ ^−). ), and phosphate ionic groups (-PO ₄ ^-), and the like.

Further, as another method of surface treatment, a compound having a functional group that reacts with a hydroxyl group on the surface of the conductive particle body and further having a functional group that can be polymerized by an addition or condensation reaction is used to obtain this compound. Examples thereof include a method of polymerizing on the surface of the conductive particle body. Examples of the functional group that reacts with the hydroxyl group on the surface of the conductive particle body include a carboxyl group and an isocyanate group, and examples of the functional group polymerized by the addition and condensation reaction include a hydroxyl group, a carboxyl group, an amino group, and (meth). ) Acryloyl group is mentioned.

The weight average molecular weight of the anionic polymer is preferably 2000 or more, more preferably 3000 or more, preferably 10,000 or less, and more preferably 8000 or less. When the weight average molecular weight is not less than the above lower limit and not more than the above upper limit, a sufficient amount of charge and flux property can be introduced on the surface of the conductive particles. Thereby, the cohesiveness of the conductive particles can be effectively enhanced at the time of conductive connection, and the oxide film on the surface of the electrode can be effectively removed at the time of connecting the member to be connected.

When the weight average molecular weight is equal to or higher than the lower limit and lower than the upper limit, it is easy to dispose the anionic polymer on the surface of the conductive particle body, and the agglomeration of the conductive particles is effectively enhanced at the time of conductive connection. And the conductive particles can be arranged more efficiently on the electrodes.

The weight average molecular weight indicates the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

The weight average molecular weight of the polymer obtained by surface-treating the main body of the conductive particles with a compound that becomes an anionic polymer is that the conductive particles are made of dilute hydrochloric acid or the like that dissolves the solder in the conductive particles and does not cause decomposition of the polymer. After removal, it can be determined by measuring the weight average molecular weight of the remaining polymer.

Regarding the amount of the anionic polymer introduced on the surface of the conductive particles, the acid value per 1 g of the 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 are added to 36 g of acetone and dispersed by ultrasonic waves for 1 minute. Then, phenolphthalein is used as an indicator and titrated with a 0.1 mol / L potassium hydroxide ethanol solution.

Next, a specific example of the 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 as a conductive material.

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

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

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

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

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

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

Examples of the base particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The base particles are preferably base particles excluding metal, and are preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles. The base particles may be copper particles.

Various organic substances are preferably used as the resin for forming the resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethylmethacrylate and polymethylacrylate; polycarbonate. , Polyaldehyde, 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, polyether ether ketone, polyether sulfone, divinylbenzene polymer, divinylbenzene-based copolymer and the like. Examples of the divinylbenzene-based copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene- (meth) acrylic acid ester copolymer. Since the hardness of the resin particles can be easily controlled within a suitable range, the resin for forming the resin particles is a weight obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. It is preferably coalesced.

When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group is a non-crosslinkable monomer. Examples thereof include 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; and methyl ( Meta) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) Alkyl (meth) acrylate compounds such as meta) acrylate and isobornyl (meth) acrylate; oxygen atoms such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate. Containing (meth) acrylate compound; nitrile-containing monomer such as (meth) acrylonitrile; vinyl ether compound such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; acid vinyl ester such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate, etc. Compounds; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride, and chlorstyrene. Can be mentioned.

Examples of the crosslinkable monomer include tetramethylol methanetetra (meth) acrylate, tetramethylol methanetri (meth) acrylate, tetramethylol methanedi (meth) acrylate, trimethylol propanetri (meth) acrylate, and dipenta. Elythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylate compounds such as acrylates, (poly) tetramethylene glycol di (meth) acrylates, 1,4-butanediol di (meth) acrylates; triallyl (iso) cyanurate, triallyl trimellitate, divinylbenzene, Examples thereof include silane-containing monomers such as diallyl phthalate, diallyl acrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and 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 suspension polymerization in the presence of a radical polymerization initiator, and a method of swelling and polymerizing a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

When the base particle is an inorganic particle other than a metal or an organic-inorganic hybrid particle, examples of the inorganic substance for forming the base particle include silica, alumina, barium titanate, zirconia, and carbon black. The particles formed of the silica are not particularly limited, but for example, after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, firing is performed as necessary. Examples include particles obtained by doing so. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

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

The method of forming the conductive portion on the surface of the base material particles and the method of forming the solder portion on the surface of the base material particles or on the surface of the second conductive portion are not particularly limited. Examples of the method for forming the conductive portion and the solder portion include a method by electroplating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, and the like. Further, a method of coating the surface of the base material particles with a metal powder or a paste containing the metal powder and the binder and the like can be mentioned. Electroless plating, electroplating or physical collision methods are preferred. Examples of the method by physical vapor deposition include methods such as vacuum deposition, ion plating, and ion sputtering. Further, in the above-mentioned physical collision method, for example, a seater composer (manufactured by Tokuju Kosakusho Co., Ltd.) or the like is used.

The melting point of the base particles is preferably higher than the melting point of the solder portion. The melting point of the base particles preferably exceeds 160 ° C., more preferably exceeds 300 ° C., further preferably exceeds 400 ° C., and particularly preferably exceeds 450 ° C. The melting point of the base particles may be less than 400 ° C. The melting point of the base particles may be 160 ° C. or lower. The softening point of the base particles is preferably 260 ° C. or higher. The softening point of the base particles may be less than 260 ° C.

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

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

The tin content may be determined using a high frequency inductively coupled plasma emission spectrophotometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu Corporation). It is measurable.

By using the conductive particles having the solder on the outer surface portion of the conductive portion, the solder melts and is bonded to the electrodes, and the solder conducts the electrodes. For example, the solder and the electrode are likely to make surface contact rather than point contact, so that the connection resistance is low. Further, by using the conductive particles having the solder on the outer surface portion of the conductive portion, the bonding strength between the solder and the electrode is increased, and as a result, the peeling between the solder and the electrode is more difficult to occur, and the conduction reliability is effective. Will be high.

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. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, tin-indium alloy and the like. The low melting point metal is preferably tin, tin-silver alloy, tin-silver-copper alloy, tin-bismuth alloy, or tin-indium alloy because of its excellent wettability to the electrode. More preferably, it is a tin-bismuth alloy or a tin-indium alloy.

The material constituting the solder (solder portion) is preferably a filler material having a liquidus line of 450 ° C. or lower based on JIS Z3001: welding terminology. Examples of the composition of the solder include a metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. A tin-indium system (117 ° C. eutectic) or a tin-bismuth system (139 ° C. eutectic), which has a low melting point and is lead-free, is preferable. 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 is nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese. , Chromium, molybdenum, palladium and the like may be contained. Further, from the viewpoint of further increasing the bonding strength between the solder and the electrode, the solder in the conductive particles preferably 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 for increasing the bonding strength is preferably 0 in 100% by weight of the solder in the conductive particles. It is .0001% by weight or more, preferably 1% by weight or less.

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

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

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

The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer or a gold layer, and further preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably have a nickel layer or a gold layer, and even more preferably have a copper layer. By using the conductive particles having these preferable conductive portions for the connection between the electrodes, the connection resistance between the electrodes is further lowered. Further, a solder portion can be more easily formed on the surface 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, still more preferably 0.3 μm or less. When the thickness of the solder portion is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles are not too hard, and the conductive particles are sufficiently deformed at the time of connection between the 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, still more preferably 0.5 μm or less. Particularly preferably, it is 0.3 μm or less. The thickness of the conductive portion is the thickness of the entire conductive layer when the conductive portion has multiple layers. When the thickness of the conductive portion is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles are not too hard, and the conductive particles are sufficiently deformed at the time of connection between the electrodes. ..

When the conductive portion is formed of a plurality of layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, more preferably. Is 0.1 μm or less. When the thickness of the conductive layer of the outermost layer is not less than the above lower limit and not more than the above upper limit, the coating by the conductive layer of the outermost layer becomes uniform, the corrosion resistance is sufficiently high, and the connection resistance between the electrodes is further increased. It gets lower. Further, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

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

The obtained conductive particles are added to "Technobit 4000" manufactured by Kulzer so as to have a content of 30% by weight and dispersed to prepare an embedded resin for conducting a conductive particle inspection. A cross section of the conductive particles is cut out using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the conductive particles dispersed in the embedded resin for inspection.

Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the conductive part of each conductive particle was observed. It is preferable to do so. It is preferable to measure the thickness of the conductive portion in the obtained conductive particles and arithmetically average the thickness to obtain the thickness of the conductive portion.

The average particle size of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 3 μm or more, preferably 100 μm or less, more preferably 50 μm or less, still more preferably 40 μm or less, and particularly preferably. Is 30 μm or less. When the average particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be arranged more efficiently on the electrodes, and more solder in the conductive particles is formed between the electrodes. It is easy to arrange and the continuity reliability is further improved.

The "average particle size" of the conductive particles indicates a number average particle size. The average particle size of the conductive particles can be obtained, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

The average particle size of the conductive particles is the single conductive particles before being mixed with the thermosetting component and the flux, and the conductive particles in the conductive material after being mixed with the thermosetting component and the flux. Is generally the same

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

The content of the conductive particles in 100% by weight of the conductive material is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, particularly preferably 20% by weight or more, and most preferably. It is 30% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, still more preferably 60% by weight or less, and particularly preferably 50% by weight or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be arranged more efficiently on the electrodes, and a large amount of solder in the conductive particles is arranged between the electrodes. It is easy to do, and the continuity reliability is further improved. From the viewpoint of further enhancing the conduction reliability, it is preferable that the content of the conductive particles is large.

(Thermosetting compound)
The thermosetting compound is a compound that can be cured by heating. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds and polyimide compounds. Epoxy compounds or episulfide compounds are preferable, and epoxy compounds are more preferable, from the viewpoint of further improving the curability and viscosity of the conductive material and further enhancing the conduction reliability and connection reliability. The conductive material preferably contains an epoxy compound. Only one kind of the thermosetting compound may be used, or two or more kinds may be used in combination.

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 triazine. It is more preferable to contain a thermosetting compound having a skeleton.

Examples of the thermosetting compound having a triazine skeleton include triazine triglycidyl ether and the like, 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) and the like.

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 equal to or lower than the melting point of the solder is preferable. The melting temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, and preferably 40 ° C. or higher. By using the above-mentioned preferable epoxy compound, the viscosity is high at the stage where the members to be connected are bonded, and when acceleration is applied due to an impact such as transportation, the first member to be connected and the second connection target are connected. It is possible to suppress the misalignment with the member, and the viscosity of the conductive material can be greatly reduced by the heat at the time of curing, and the aggregation of the solder can be efficiently promoted.

The content of the thermosetting compound in 100% by weight of the conductive material is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and preferably 99% by weight or less. It is more preferably 98% by weight or less, further preferably 90% by weight or less, and particularly preferably 80% by weight or less. From the viewpoint of further enhancing the impact resistance, it is preferable that the content of the thermosetting compound is large.

(Thermosetting agent)
The thermosetting agent heat-cures the thermosetting compound. Examples of the heat curing agent include an imidazole curing agent, a phenol curing agent, a thiol curing agent, an amine curing agent, an acid anhydride curing agent, a thermal cation initiator, a thermal radical generator and the like. Only one type of the thermosetting agent may be used, or two or more types may be used in combination.

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

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

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

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

Examples of the thermal cation initiator include an iodonium-based cation curing agent, an oxonium-based cation curing agent, and a sulfonium-based cation curing agent. Examples of the iodine-based cationic curing agent include bis (4-tert-butylphenyl) iodinenium hexafluorophosphate and the like. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate.

The thermal radical generator is not particularly limited, and examples thereof include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. 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, still more preferably 80 ° C. or higher, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, still more preferably 150 ° C. or higher. Below, it is particularly preferably 140 ° C. or lower. When the reaction start temperature of the thermosetting agent is not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles is more efficiently arranged on the electrode. It is particularly preferable that the reaction start temperature of the thermosetting agent is 80 ° C. or higher and 140 ° C. or lower.

From the viewpoint of more efficiently arranging the solder in the conductive particles on the electrode, the reaction start temperature of the thermal curing agent is preferably higher than the melting point of the solder in the conductive particles, and is 5 ° C. or higher. Is more preferable, and it is even more preferable that the temperature is 10 ° C. or higher.

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

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 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, and more preferably. It is 100 parts by weight or less, more preferably 75 parts by weight or less. When the content of the thermosetting agent is at least the above lower limit, it is easy to sufficiently cure the conductive material. When the content of the thermosetting agent is not more than the above upper limit, it becomes difficult for the surplus thermosetting agent that was not involved in the curing to remain after curing, and the heat resistance of the cured product is further increased.

(flux)
The conductive material contains a flux. The use of flux allows the solder in the conductive particles to be more effectively placed on the electrodes. Further, in the present invention, the flux is a combination of an acid having an effect of cleaning the surface of a metal and a base having an effect of neutralizing the acid, and is a salt of these acids and a base.

When the flux, which is a salt of this specific acid and base, is solid at 25 ° C., the storage stability of the conductive material becomes high, and after the conductive material is placed on the member to be connected, it is left for a long time. Also, since it exhibits excellent solder cohesiveness, it is possible to provide a conductive material capable of exhibiting high conduction reliability. The flux is preferably a salt of an acid and a base and is preferably 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 preferably a salt of an organic compound having a carboxyl group and an organic compound having an amino group.

Further, from the viewpoint of effectively increasing the storage stability of the conductive material, exhibiting excellent solder cohesiveness even when the conductive material is left for a long time after being placed on the member to be connected, and exhibiting high conduction reliability. Therefore, the flux, which is a salt of a specific acid and a base, is preferably solid at 25 ° C. Only one kind of the above flux may be used, or two or more kinds of the flux may be used in combination.

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

Examples of the carboxylic acid or carboxylic acid anhydride include succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, malic acid, which are aliphatic carboxylic acids, and cyclohexylcarboxylic acid, 1,4 which is a cyclic aliphatic carboxylic acid. -Cyclohexyldicarboxylic acid, aromatic carboxylic acid isophthalic acid, terephthalic acid, trimellitic acid, and ethylenediamine tetraacetic acid, and acid anhydrides thereof and the like can be mentioned.

In order to further enhance the flux effect, the acid and the organic compound having a carboxyl group preferably have a plurality of carboxyl groups. Examples of the organic compound having a plurality of carboxyl groups include dicarboxylic acid and tricarboxylic acid. Further, in order to facilitate the formation of a salt, 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, preferably 4 or more. Is 8 or less.

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

Among the above amino group-containing compounds, examples of the amino group-containing compound having no aromatic skeleton include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine and dicyclohexylamine.

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

The active temperature (melting point) of the flux is preferably 40 ° C. or higher, more preferably 50 ° C. or higher. When the active temperature of the flux is at least the above lower limit, the storage stability is further improved.

From the viewpoint of more efficiently arranging the solder in the conductive particles on the electrode, the melting point of the flux is preferably -50 ° C or higher, more preferably the melting point of the solder in the conductive particles, and more preferably the solder in the conductive particles. The melting point is −30 ° C. or higher, preferably the melting point of the solder in the conductive particles + 50 ° C. or lower, more preferably the melting point of the solder in the conductive particles + 30 ° C. or lower, and more preferably less than the melting point of the solder in the conductive particles. be. When the melting point of the flux is equal to or higher than the lower limit and lower than the upper limit, the flux effect is more effectively exhibited and the solder is more efficiently arranged on the electrode.

From the viewpoint of more efficiently arranging 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, and more preferably 5 ° C. or higher. It is more preferable that the temperature is as low as 10 ° C. or higher.

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

The flux exists as a solid in a conductive material at 25 ° C. 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. Further, when the conductive material is placed on the member to be connected and the conductive material is placed in contact with air for a long time, the reaction between the flux and the thermosetting compound is promoted by the moisture in the air, or the flux and the solder Metal ions may be generated by the reaction with the surface of the solder, which may adversely affect the cohesiveness of the solder and 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 is affected by the above, so that it has high storage stability, high conductivity even after being left for a long time, and insulation. Can express sex.

Further, 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, at room temperature (23 ° C.). It is possible to impart a chixo property to a conductive material. As a result, it is possible to prevent the settling of the conductive particles and to develop the shape retention after coating, and it is possible to further prevent the conductive material from flowing out to unnecessary places. When the conductive material is a film, since the flux is solid, the liquid content in the conductive material can be reduced, so that the cutability of the film can be improved and the exudation from the cut surface can be suppressed. can do.

Further, when the flux melts at a temperature lower than the melting point of the solder, the flux is melted at the melting point of the solder, so that the melt viscosity of the conductive material is sufficiently lowered, and even better solder cohesiveness is exhibited. be able to.

Further, when the flux melts at a temperature lower than the melting point of the solder, the flux dissolves in the thermosetting compound or the thermosetting agent above the melting point of the solder, and further, the thermosetting compound or the thermosetting agent. When the carboxyl group and amino group of the flux react with each other, the flux component is incorporated into the curing system. As a result, high insulation between adjacent electrodes can be exhibited, and corrosion of the electrodes can be prevented.

In the conductive material at 25 ° C., the average particle size of the flux is preferably 30 μm or less. When the average particle size of the flux is in 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 size of the flux is preferably 0.1 μm or more.

The "average particle size" of the above flux indicates a number average particle size. The average particle size of the flux is obtained, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

There is a difference in the average particle size of the flux between the single flux before being mixed with the conductive particles and the thermosetting component and the flux in the conductive material after being mixed with the conductive particles and the thermosetting component. If not, the average particle size can be evaluated with the flux alone before being mixed with the conductive particles and the thermosetting component.

Further, in the conductive material at 25 ° C., the ratio of the average particle size of the flux to the average particle size of the conductive particles (average particle size of the flux / average particle size of the conductive particles) is preferably 3 or less, more preferably. Is 1 or less, more preferably 0.2 or less. When the above ratio is not more than the above upper limit, the flux can be effectively brought into contact with the conductive particles, and the flux performance at the time of heating can be further improved. For the same reason, the above ratio (average particle size of flux / average particle size of conductive particles) is preferably 0.005 or more, more preferably 0.01 or more, still more preferably 0.02 or more.

In 100% by weight of the 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 highly accurate control of the spacing between the members to be connected connected by the cured product of the conductive material and the spacing between the members to be connected connected by the solder in the conductive particles, the conductive material is an insulating particle. It is preferable to include. In the conductive material, the insulating particles may not be attached to the surface of the conductive particles. In the conductive material, the insulating particles are preferably present apart from the conductive particles.

The average particle size of the insulating particles is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 25 μm or more, preferably 100 μm or less, more preferably 75 μm or less, still more preferably 50 μm or less. When the average particle size of the insulating particles is equal to or greater than the above lower limit and equal to or less than the above upper limit, the distance between the members to be connected connected by the cured product of the conductive material and the distance between the members to be connected connected by the solder in the conductive particles. The interval between the two becomes even more appropriate.

The "average particle size" of the insulating particles indicates a number average particle size. The average particle size of the insulating particles can be obtained, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

In addition, the insulating particles alone before being mixed with the conductive particles, the thermosetting component and the flux, and the insulating particles in the conductive material after being mixed with the conductive particles, the thermosetting component and the flux. The average particle size of the insulating particles is generally the same.

Examples of the material of the insulating particles include an insulating resin and an insulating inorganic substance. Examples of the insulating resin include the above-mentioned resins mentioned as resins for forming resin particles that can be used as base particles. Examples of the insulating inorganic substance include the above-mentioned inorganic substances mentioned as the inorganic substances for forming the inorganic particles that can be used as the 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, and heat. Examples thereof include curable resins and water-soluble resins.

Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer and the like. 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, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. Examples of the thermosetting resin include epoxy resin, phenol resin, melamine resin and the like. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, methyl cellulose and the like. Of these, a water-soluble resin is preferable, and polyvinyl alcohol is more preferable.

The content of the insulating particles in 100% by weight of the conductive material is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 10% by weight or less, and more preferably 5% by weight. It is as follows. The conductive material may not contain insulating particles. When the content of the insulating particles is equal to or greater than the above lower limit and equal to or less than the above upper limit, the spacing between the members to be connected connected by the cured product of the conductive material and the spacing between the members to be connected connected by the solder in the conductive particles. Becomes even more moderate.

(Other ingredients)
The conductive material may be, for example, a filler, a bulking agent, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, or a lubricant, if necessary. , Antistatic agents, flame retardants and other various additives may be contained.

(Connection structure and manufacturing method of connection structure)
The connection structure according to the present invention includes a first connection target member having at least one first electrode on the surface, a second connection target member having at least one second electrode on the surface, and the first connection target member. The connection target member is provided with a connection portion connecting the second connection target member. In the connection structure according to the present invention, the material of the connection portion is the above-mentioned conductive material, and the above-mentioned connection portion 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 method for manufacturing the connection structure includes a step of arranging the conductive material on the surface of a first connection target member having at least one first electrode on the surface using the above-mentioned conductive material, and the above-mentioned conductivity. A second connection target member having at least one second electrode on the surface on the surface of the material opposite to the first connection target member side is provided by the first electrode and the second electrode. A connection in which the first connection target member and the second connection target member are connected by heating the conductive material above the melting point of the solder in the conductive particles and the step of arranging them so as to face each other. The portion is formed of a cured product of the conductive material, and includes a step of electrically connecting the first electrode and the second electrode by a solder portion in the connecting portion. Preferably, the conductive material is heated above the curing temperature of the thermosetting component and the thermosetting compound.

Since a specific conductive material is used in the connection structure according to the present invention and the method for manufacturing the connection structure, solder in a plurality of conductive particles tends to collect between the first electrode and the second electrode. , Solder can be efficiently placed on the electrode (line). Further, it is difficult for a part of the solder to be arranged in the region (space) where the electrode is not formed, and the amount of the solder arranged in the region where the electrode is not formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. Moreover, it is possible to prevent electrical connection between horizontally adjacent electrodes that should not be connected, and it is possible to improve insulation reliability.

Further, in order to efficiently arrange the solder in the plurality of conductive particles on the electrodes and to considerably reduce the amount of the solder arranged in the region where the electrodes are not formed, a conductive paste is used instead of the conductive film. It is preferable to use it.

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. The solder wet area on the surface of the electrode (the area in contact with the solder in 100% of the exposed area of the electrode, the first electrode and the first electrode before forming the connection portion are electrically connected to each other. The area in contact with the solder portion after forming the connection portion with respect to the exposed area of 100% with the second electrode) is preferably 50% or more, more preferably 70% or more, and is preferable. Is 100% or less.

In the method for manufacturing a connection structure according to the present invention, no pressurization is performed in the step of arranging the second connection target member and the step of forming the connection portion, and the second connection is made to the conductive material. Pressurization is performed and the second connection target member is pressed in at least one of the steps of adding the weight of the target member or arranging the second connection target member and forming the connection portion. It is preferable that the pressurizing pressure is less than 1 MPa in both the step of arranging the above and the step of forming the connection portion. By not applying a pressure of 1 MPa or more, the aggregation of the solder in the conductive particles is considerably promoted. From the viewpoint of suppressing warpage of the connection target member, in the method for manufacturing a connection structure according to the present invention, addition is performed in at least one of the step of arranging the second connection target member and the step of forming the connection portion. The pressure of pressurization may be less than 1 MPa in both the step of applying pressure and arranging the second connection target member and the step of forming the connection portion. When pressurizing, pressurization may be performed only in the step of arranging the second connection target member, or pressurization may be performed only in the step of forming the connection portion. Pressurization may be performed in both the step of arranging the connection target member and the step of forming the connection portion. The pressure of pressurization is less than 1 MPa includes the case of not pressurizing. When pressurizing, the pressurizing pressure is preferably 0.9 MPa or less, more preferably 0.8 MPa or less. When the pressurizing pressure is 0.8 MPa or less, the aggregation of the solder in the conductive particles is further remarkably promoted as compared with the case where the pressurizing pressure exceeds 0.8 MPa.

In the method for manufacturing a connection structure according to the present invention, no pressurization is performed in the step of arranging the second connection target member and the step of forming the connection portion, and the second connection is made to the conductive material. It is preferable that the weight of the target member is added, and in the step of arranging the second connection target member and the step of forming the connection portion, the conductive material exceeds the force of the weight of the second connection target member. It is preferable that no pressurizing pressure is applied. In these cases, the uniformity of the soldering amount can be further improved in the plurality of soldered portions. Further, the thickness of the solder portion can be increased more effectively, and a large amount of solder in a plurality of conductive particles can easily collect between the electrodes, and the solder in a plurality of conductive particles can be more efficiently collected on the electrode (line). Can be arranged as a target. Further, it is difficult for a part of the solder in the plurality of conductive particles to be arranged in the region (space) where the electrode is not formed, and the amount of the solder in the conductive particles arranged in the region where the electrode is not formed is further increased. Can be reduced. Therefore, the continuity reliability between the electrodes can be further improved. Moreover, it is possible to further prevent electrical connection between electrodes adjacent in the lateral direction that should not be connected, and it is possible to further improve insulation reliability.

Further, in the step of arranging the second connection target member and the step of forming the connection portion, if no pressurization is performed and the weight of the second connection target member is added to the conductive material, the connection portion is formed. The solder that was placed in the area (space) where the electrodes were not formed before being formed becomes easier to collect between the first electrode and the second electrode, and the solder in the plurality of conductive particles is attached to the electrodes (the electrodes). The present inventors have also found that the arrangement can be performed more efficiently on the line). In the present invention, a configuration in which a conductive paste is used instead of a conductive film and a configuration in which the weight of the second connection target member is added to the conductive paste without applying pressure are adopted in combination. It is of great significance to do so in order to obtain the effect of the present invention at an even higher level.

In WO2008 / 023452A1, it is described that it is preferable to pressurize at a predetermined pressure at the time of bonding from the viewpoint of pushing the solder powder to the electrode surface and moving it efficiently, and the pressurizing pressure further ensures the solder region. From the viewpoint of forming the adhesive tape, for example, it is described that the pressure is 0 MPa or more, preferably 1 MPa or more, and even if the pressure intentionally applied to the adhesive tape is 0 MPa, the member arranged on the adhesive tape It is stated that a predetermined pressure may be applied to the adhesive tape due to its own weight. WO2008 / 023452A1 describes that the pressure intentionally applied to the adhesive tape may be 0 MPa, but there is no difference in the effect between the case where the pressure exceeding 0 MPa is applied and the case where the pressure is 0 MPa. Not listed. Further, in WO2008 / 023452A1, the importance of using a paste-like conductive paste instead of a film-like one is not recognized at all.

Further, if a conductive paste is used instead of the conductive film, it becomes easy to adjust the thickness of the connecting portion and the solder portion depending on the amount of the conductive paste applied. On the other hand, in the case of the conductive film, in order to change or adjust the thickness of the connecting portion, it is necessary to prepare a conductive film having a different thickness or a conductive film having a predetermined thickness. There is. Further, in the conductive film, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder as compared with the conductive paste, and the aggregation of the solder tends to be easily hindered.

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

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

The connection structure 1 shown in FIG. 1 is a connection connecting the first connection target member 2, the second connection target member 3, the first connection target member 2, and the second connection target member 3. A unit 4 is provided. The connecting portion 4 is formed of the above-mentioned conductive material. In the present embodiment, the conductive material includes solder particles as the conductive particles.

The connecting portion 4 has a solder portion 4A in which a plurality of solder particles are gathered and bonded to each other, and a cured product portion 4B in which a thermosetting component is thermoset. In this embodiment, solder particles are used as the conductive particles in order to form the solder portion 4A. Both the central portion and the outer surface of the conductive portion of the solder particles are formed of solder.

The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. In the connecting portion 4, no solder is 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. In the region different from the solder portion 4A (cured product portion 4B portion), there is no solder separated from the solder portion 4A. If the amount is small, the 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 are gathered between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the melt of the solder particles is formed. The surface of the electrode is wet and spread, and then solidified to form the solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a and the solder portion 4A and the second electrode 3a becomes large. That is, by using the solder particles, the solder portion 4A, the first electrode 2a, and the solder are compared with the case where the outer surface portion of the conductive portion is a metal such as nickel, gold, or copper. The contact area between the portion 4A and the second electrode 3a becomes large. Therefore, the continuity reliability and the connection reliability in the connection structure 1 are improved.

In the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in facing regions between the first and second electrodes 2a and 3a. In the connection structure 1X of the modified example shown in FIG. 3, only the connection portion 4X is different from the connection structure 1 shown in FIG. The connection portion 4X has a solder portion 4XA and a cured product portion 4XB. Like the connection structure 1X, most of the solder portions 4XA are located in the facing regions of the first and second electrodes 2a and 3a, and a part of the solder portions 4XA is the first and second electrodes. The electrodes 2a and 3a may protrude laterally from the facing regions. The solder portion 4XA protruding laterally from the facing regions of the first and second electrodes 2a and 3a is a part of the solder portion 4XA, and is not the solder separated from the solder portion 4XA. In this embodiment, the amount of solder separated from the solder portion can be reduced, but the solder separated from the solder portion may be present in the cured product portion.

If the amount of solder particles used is reduced, it becomes easy to obtain the connection structure 1. If the amount of solder particles used is increased, it becomes easy to obtain the connection structure 1X.

From the viewpoint of further enhancing the conduction reliability, in the connection structure 1, 1X, the first electrode 2a and the second electrode 2a and the second electrode 2a are in the stacking direction of the first electrode 2a, the connection portions 4, 4X, and the second electrode 3a. When looking at the portions facing each other with the electrode 3a, 50% or more (more preferably 60% or more, still more preferably 60% or more) of the area of the facing portions of the first electrode 2a and the second electrode 3a is 100%. It is preferable that the solder portions 4A and 4XA in the connecting portions 4 and 4X are arranged in 70% or more, particularly preferably 80% or more, and most preferably 90% or more).

From the viewpoint of further enhancing the conduction reliability, the portion where the first electrode and the second electrode face each other is seen in the stacking direction of the first electrode, the connection portion, and the second electrode. Occasionally, 50% or more (more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more) of the area of the portion where the first electrode and the second electrode face each other is 100% or more. , Most preferably 90% or more), it is preferable that the solder portion in the connection portion is arranged.

From the viewpoint of further enhancing conduction reliability, the first electrode and the second electrode face each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode. When looking at the mating portions, 60% or more (more preferably 70% or more, still more preferably 80) of the solder portion in the connection portion is in the facing portion between the first electrode and the second electrode. % Or more, more preferably 90% or more, particularly preferably 95% or more, and most preferably 99% or more).

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

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

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

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

Further, a second connection target member 3 having the second electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B, in the conductive material 11 on the surface of the first connection target member 2, on the surface of the conductive material 11 opposite to the first connection target member 2 side. The second connection target member 3 is arranged (second step). The second connection target member 3 is arranged 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 above the melting point of the solder particles 11A (third step). Preferably, the conductive material 11 is heated above the curing temperature of the thermosetting component 11B (binder). At the time of this heating, the solder particles 11A existing in the region where the electrodes are not formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). When a conductive paste is used instead of the conductive film, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. Further, the solder particles 11A are melted and bonded to each other. Further, the thermosetting component 11B is thermoset. As a result, as shown in FIG. 2C, the connecting portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connecting portion 4 is formed by the conductive material 11, the solder portion 4A is formed by joining the plurality of solder particles 11A, and the cured product portion 4B is formed by thermosetting the thermosetting component 11B. If the solder particles 11A move sufficiently, the solder particles 11A that are not located between the first electrode 2a and the second electrode 3a start to move, and then the first electrode 2a and the second electrode 2a and the second electrode It is not necessary to keep the temperature constant until the movement of the solder particles 11A to and from 3a is completed.

In the present embodiment, it is preferable not to pressurize in the second step and the third step. In this case, the weight of the second connection target member 3 is added to the conductive material 11. Therefore, when the connecting portion 4 is formed, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. If pressure is applied in at least one of the second step and the third step, the action of solder particles to collect between the first electrode and the second electrode is hindered. The tendency is high.

Further, in the present embodiment, since the pressure is not applied, when the second connection target member is superposed on the first connection target member coated with the conductive material, the electrode of the first connection target member is used. Even if the first connection target member and the second connection target member are overlapped with each other in a state where the electrodes of the second connection target member are misaligned, the misalignment is corrected and the first connection target member is corrected. The electrode of the above and the electrode of the second connection target member can be connected (self-alignment effect). This is because the molten solder that self-aggregates between the electrode of the first connection target member and the electrode of the second connection target member is the electrode of the first connection target member and the electrode of the second connection target member. Since the area where the solder between the solder and other components of the conductive material come into contact with each other is the smallest, it is energetically stable. This is because. At this time, it is desirable that the conductive material is not cured and that the viscosity of the components other than the conductive particles of the conductive material is sufficiently low at the temperature and time.

In this way, the connection structure 1 shown in FIG. 1 is obtained. The second step and the third step may be continuously performed. Further, after performing the second step, the obtained laminate of the first connection target member 2, the conductive material 11 and the second connection target member 3 is moved to the heating unit, and the third The process may be performed. In order to perform the heating, the laminate may be arranged on the heating member, or the laminate may be arranged in the heated space.

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

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

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

When locally heating on a hot plate, use a metal with high thermal conductivity directly under the connection, and use a material with low thermal conductivity such as fluororesin in other areas where heating is not preferable. , It is preferable to form the upper surface of the hot plate.

The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors and diodes, resin films, printed circuit boards, flexible printed circuit boards, and flexible devices. Examples thereof include electronic components such as flat cables, rigid flexible boards, glass epoxy boards, circuit boards such as glass boards, and the like. The first and second connection target members are preferably 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 substrate, a rigid flexible substrate or a flexible flat cable, and a resin film and a flexible print. More preferably, it is a substrate, a flexible flat cable or a rigid flexible substrate. The second connection target member is preferably a semiconductor chip, a resin film, a flexible printed substrate, a rigid flexible substrate or a flexible flat cable, and more preferably a resin film, a flexible printed substrate, a flexible flat cable or a rigid flexible substrate. preferable. Resin films, flexible printed substrates, flexible flat cables and rigid flexible substrates have the properties of high flexibility and relatively light weight. When a conductive film is used for connecting such a member to be connected, the solder in the conductive particles tends to be difficult to collect on the electrode. On the other hand, by using the conductive paste, even if a resin film, a flexible printed substrate, a flexible flat cable or a rigid flexible substrate is used, the solder in the conductive particles can be efficiently collected on the electrodes, and the electrodes can be separated from each other. Conduction reliability can be sufficiently enhanced. When a resin film, flexible printed substrate, flexible flat cable, or rigid flexible substrate is used, the conduction reliability between the electrodes due to no pressurization is higher than when other connected members such as semiconductor chips are used. The improvement effect can be obtained even more effectively.

The form of the connection target member includes a peripheral, an area array, and the like. As a feature of each member, in the peripheral substrate, the electrodes are present only on the outer peripheral portion of the substrate. In the area array substrate, electrodes are present in the plane.

Examples of the electrode provided on the connection target member include a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, a SUS electrode, and a metal electrode such as a tungsten electrode. When the connection target member is a flexible printed substrate, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. When the 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 of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al and Ga.

Hereinafter, the present invention will be specifically described with reference to 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 Kyoeisha Chemical Co., Ltd., epoxy equivalent 120 g / eq

Thermosetting compound 2: Highly reactive epoxy compound, "EP-3300S" manufactured by ADEKA CORPORATION, epoxy equivalent 165 g / eq

Thermosetting agent 1: Trimethylolpropanetris (3-mercaptopropinate), SC Organic Chemical Co., Ltd. "TMMP"

Thermosetting agent 2: Todipentaerythritol hexakis (3-mercaptopropionate), SC Organic Chemical Co., Ltd. "DPMP"

Latent Epoxy Thermosetting Agent 1: "Fuji Cure 7000" manufactured by T & K TOKA

Method for producing flux 1:
160 g of acetone and 32 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a three-necked flask and dissolved at room temperature until uniform. Then, 26 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 30 minutes, and after the addition was completed, the mixture was stirred at room temperature for 2 hours. The precipitated white crystals were separated by filtration, washed with acetone and vacuum dried to obtain flux 1. The average particle size was measured with 50 arbitrary particles using a scanning electron microscope (“S-4300SEN” manufactured by Hitachi, Ltd.), and the average value was calculated. As for the melting point, the endothermic peak was measured by DSC (“DSC6200” manufactured by Seiko Instruments Inc.).

Method for producing flux 2:
The white crystals obtained by the same method as for flux 1 were pulverized in a mortar until the average particle size became 10 μm to obtain flux 2.

Method for producing flux 3:
The white crystals obtained by the same method as for flux 1 were pulverized in a mortar until the average particle size became 1 μm to obtain flux 3.

Method for producing flux 4:
The white crystals obtained by the same method as for flux 1 were pulverized in a mortar until the average particle size became 0.05 μm to obtain flux 4.

Method for producing flux 5:
160 g of acetone and 31 g of cyclohexanecarboxylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a three-necked flask and dissolved at room temperature until uniform. Then, 24 g of cyclohexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 30 minutes, and after the addition was completed, the mixture was stirred at room temperature for 2 hours. The precipitated white crystals were separated by filtration, washed with acetone, and vacuum dried. Then, in a mortar, it was pulverized until the average particle size became 10 μm to obtain a flux 5.

Method for producing flux 6:
Acetone (160 g) and adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.) (35 g) were placed in a three-necked flask and dissolved at room temperature until uniform. Then, 26 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 30 minutes, and after the addition was completed, the mixture was stirred at room temperature for 2 hours. The precipitated white crystals were separated by filtration, washed with acetone, and vacuum dried. Then, in a mortar, it was pulverized until the average particle size became 10 μm to obtain a flux 6.

How to make flux 7:
To 12.6 g of citric acid monohydrate, 26.8 g of triethanolamine was added to a three-necked flask, and citric acid was dissolved while stirring in an oil bath at 120 ° C. The obtained triethanolamine citrate salt was liquid at 25 ° C.

Method for producing flux 8:
In a three-necked flask, 37.25 g of triethanolamine was added to 35.0 g of glutaric acid, and glutaric acid was dissolved while stirring in an oil bath at 120 ° C. The obtained glutaric acid triethanolamine salt was semi-solid at 25 ° C.

Regarding the flux solid at 25 ° C., the flux alone before being mixed with the conductive particles and the thermosetting component and the flux in the conductive material after being mixed with the conductive particles and the thermosetting component are used. , The average particle size of the flux was the same.

Solder particles 1 (SnBi solder particles, melting point 139 ° C., "DS-10" manufactured by Mitsui Mining & Smelting Co., Ltd., average particle diameter (median diameter 12 μm))

Solder particles 2 (SAC solder particles, melting point 217 ° C, "DS-10" manufactured by Mitsui Mining & Smelting Co., Ltd., average particle diameter (median diameter 12 μm))

Method for producing solder particles 3:
160 g of acetone and 32 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a three-necked flask and dissolved at room temperature until uniform. Then, 100 g of the 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 after the addition was completed, the solder particles were stirred at room temperature for 2 hours to obtain the solder particles. Flux was deposited on the surface. Then, the solder particles were washed once with acetone and vacuum dried to obtain solder particles 3.

(Examples 1 to 6, 9, 11 to 17 , Reference Examples 7, 8 and 10 and Comparative Examples 1 to 2)
(1) Preparation of Anisotropic Conductive Paste The components shown in Tables 1 and 2 below were blended in the blending amounts shown in Tables 1 and 2 below to obtain an anisotropic conductive paste. In the obtained anisotropic conductive paste, the flux was present in the states shown in Tables 1 and 2.

(2) Preparation of Connection Structure (Area Array) As the first connection target member, a copper electrode having a diameter of 250 μm and a thickness of 10 μm is placed on the surface of a semiconductor chip body (size 5 × 5 mm, thickness 0.4 mm) at a pitch of 400 μm. , The semiconductor chips arranged in the area array were prepared. The number of copper electrodes is 10 x 10 per semiconductor chip, for a total of 100.

As the second connection target member, the same pattern is formed on the surface of the glass epoxy substrate main body (size 20 × 20 mm, thickness 1.2 mm, material FR-4) with respect to the electrodes of the first connection target member. , A glass epoxy substrate was prepared in which a solder resist film was formed in a region where a gold electrode was arranged and a gold electrode was not arranged. The step between the surface of the copper electrode and the surface of the solder resist film is 15 μm, and the solder resist film protrudes from the copper electrode.

An anisotropic conductive paste immediately after production was applied to the upper surface of the glass epoxy substrate so as to have a thickness of 50 μm to form an anisotropic conductive paste layer. After standing at 23 ° C. and 50% RH for 2 hours, semiconductor chips were laminated on the upper surface of the anisotropic conductive paste layer so that the electrodes face each other. The weight of the semiconductor chip is added to the anisotropic conductive paste layer. From that state, the temperature of the anisotropic conductive paste layer was 139 in the melting points of the solder (Examples 1 to 6, 9 , 12 to 17, Reference Examples 7 and 8 and Comparative Examples 1 and 2) 5 seconds after the start of temperature rise. The temperature was increased to 217 ° C. in Reference Example 10 and Example 11). Further, 15 seconds after the start of temperature rise, the temperature of the anisotropic conductive paste layer is the melting point of the solder + 21 ° C. (Examples 1 to 6, 9 , 12 to 17, Reference Examples 7 and 8 and Comparative Examples 1 and 2 are 160. The anisotropic conductive paste layer was cured by heating at ° C., Reference Example 10 and Example 11 at 238 ° C.) and holding for 5 minutes to obtain a connecting structure. No pressurization was performed during heating.

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

(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 at 25 ° C. and 5 rpm using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.). Storage stability was judged according to the following criteria.

[Criteria for storage stability]
○○: Viscosity after storage is within ± 25% of viscosity before storage ○: Viscosity after storage does not correspond to the standard of ○○, and viscosity after storage is within ± 50% of viscosity before storage △: Standard of ○○ and ○ And the viscosity after storage is within ± 75% of the viscosity before storage ×: Does not correspond to the criteria of ○○, ○ and △

(3) Thickness of solder portion The thickness of the solder portion located between the upper and lower electrodes was evaluated by observing the cross section of the obtained connection structure.

(4) Solder placement accuracy on electrodes 1
In the obtained connection structure, when the portions facing each other of the first electrode and the second electrode are seen in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode are used. The ratio X of the area where the solder portion in the connection portion is arranged in the area of 100% of the portions facing each other with the second electrode was evaluated. The solder placement accuracy 1 on the electrode was determined according to the following criteria.

[Criteria for determining solder placement accuracy 1 on electrodes]
○ ○: Ratio X is 70% or more ○: Ratio X is 60% or more and less than 70% Δ: Ratio X is 50% or more and less than 60% ×: Ratio X is less than 50%

(5) Solder placement accuracy on electrodes 2
In the obtained connection structure, when the portions facing each other of the first electrode and the second electrode are seen in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, they are connected. The ratio Y of the solder portion in the connection portion arranged at the portion where the first electrode and the second electrode face each other in the solder portion 100% in the portion was evaluated. The solder placement accuracy 2 on the electrode was determined according to the following criteria.

[Criteria for determining solder placement accuracy 2 on electrodes]
○ ○: 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 the upper and lower electrodes In the obtained connection structure (n = 15 pieces), the connection resistance per connection point between the upper and lower electrodes was measured by the 4-terminal method. The average value of the connection resistance was calculated. From the relationship of voltage = current × resistance, the connection resistance can be obtained by measuring the voltage when a constant current is passed. The continuity reliability was judged according to the following criteria. However, when even one of the n = 15 electrodes did not conduct electricity between the upper and lower electrodes, it was determined to be "x".

[Criteria for continuity reliability]
○ ○: Average value of connection resistance is 50 mΩ or less ○: Average value of connection resistance is more than 50 mΩ, 70 mΩ or less △: Average value of connection resistance is more than 70 mΩ, 100 mΩ or less ×: Average value of connection resistance is more than 100 mΩ Or there is a poor connection

(7) Insulation reliability between electrodes adjacent in the lateral direction In the obtained connection structure (n = 15 pieces), after being left in an atmosphere of 85 ° C. and humidity of 85% for 100 hours, between the electrodes adjacent in the lateral direction. 15V was applied to, and the resistance value was measured at 25 points. The insulation reliability was judged according to the following criteria. However, when even one of the n = 15 electrodes is conducting between adjacent electrodes in the lateral direction, it is determined to be "x".

[Criteria for insulation reliability]
○○○: ○○ average value of connection resistance ^{10 14} Omega above: average value of connection resistance 10 ⁸ Omega to less than ^{10 14} Omega ○: Average connection resistance 10 ⁶ Omega to less than 10 ⁸ Omega △ : connection average value of the resistance is 10 ⁵ Omega to less than 10 ⁶ Omega ×: average value of connection resistance is less than 10 ⁵ Omega

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

1,1X ... Connection structure 2 ... First connection target member 2a ... First electrode 3 ... Second connection target member 3a ... Second electrode 4,4X ... Connection part 4A, 4XA ... Solder part 4B, 4XB … Hardened material 11… Conductive material 11A… Solder particles (conductive particles)
11B ... Thermosetting component 21 ... Conductive particles (solder particles)
31 ... Conductive particles 32 ... Base particles 33 ... Conductive parts (conductive parts with solder)
33A ... Second conductive part 33B ... Solder part 41 ... Conductive particles 42 ... Solder part

Claims (12)

A plurality of conductive particles having solder on the outer surface of the conductive part,
Thermosetting ingredients and
Including flux
The flux is a salt of an organic compound having a carboxyl group and benzylamine .
The flux exists as a solid in a conductive material at 25 ° C.
The average particle size of the flux is 0.1μm or more, Ru der below 30 [mu] m, a conductive material. The conductive material according to claim 1, wherein the flux alone is a solid at 25 ° C. without being mixed with the conductive particles and the thermosetting component. The conductive material according to claim 1 or 2 , wherein the ratio of the average particle diameter of the flux to the average particle diameter of the conductive particles is 3 or less. The conductive material according to any one of claims 1 to 3 , wherein the melting point of the flux is -50 ° C or higher for the melting point of the solder in the conductive particles and + 50 ° C or lower for the melting point of the solder in the conductive particles. The conductive material according to any one of claims 1 to 4 , wherein the conductive particles are solder particles. The conductive material according to any one of claims 1 to 5 , wherein the thermosetting component contains a thermosetting compound having a triazine skeleton. The conductive material according to any one of claims 1 to 6 , wherein the flux is adhered to the surface of the conductive particles. The conductive material according to any one of claims 1 to 7 , wherein the average particle diameter of the conductive particles is 1 μm or more and 40 μm or less. The conductive material according to any one of claims 1 to 8 , 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 conductive material. The conductive material according to any one of claims 1 to 9 , which is a conductive paste. A first connection target member having at least one first electrode on the surface,
A second connection target member having at least one second electrode on the surface,
A connection portion connecting the first connection target member and the second connection target member is provided.
The material of the connection portion is the conductive material according to any one of claims 1 to 10.
A connection structure in which the first electrode and the second electrode are electrically connected by a solder portion in the connection portion. When the portions facing each other of the first electrode and the second electrode are seen in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the first electrode are seen. The connection structure according to claim 11 , wherein the solder portion in the connection portion is arranged in 50% or more of the area of 100% of the portions facing the electrodes of 2.

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