WO2017130892A1

WO2017130892A1 - Conductive material and connection structure

Info

Publication number: WO2017130892A1
Application number: PCT/JP2017/002089
Authority: WO
Inventors: 宏夏井; 周治郎定永; 将大伊藤; 秀文保井; 石澤　英亮
Original assignee: 積水化学工業株式会社
Priority date: 2016-01-25
Filing date: 2017-01-23
Publication date: 2017-08-03
Also published as: JP2021185579A; KR102618237B1; TWI778950B; TW201732841A; KR20180105110A; CN108028090A; CN108028090B; JP6966322B2; JPWO2017130892A1; TW202331749A

Abstract

Provided is a conductive material capable of providing high conduction reliability since the conductive material has high storage stability, and shows, after being arranged on a member to be connected, excellent solder cohesiveness performance, even if being left for a long time. The conductive material according to the present invention contains, in the outer surface portion of a conductive portion: a plurality of conductive particles having solder; a thermosetting component; and flux. The flux is a salt of an acid and a base. The flux is present as a solid in the conductive material at 25°C.

Description

Conductive material and connection structure

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

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

In order to obtain various connection structures, for example, the anisotropic conductive material may be connected between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), or connected between a semiconductor chip and a flexible printed circuit board (COF ( (Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

For example, when electrically connecting the electrode of the flexible printed circuit board and the electrode of the glass epoxy substrate by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. To do. Next, a flexible printed circuit board is laminated, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

As an example of the anisotropic conductive material, the following Patent Document 1 describes an anisotropic conductive material including conductive particles and a resin component that cannot be cured at the melting point of the conductive particles. Specifically, the conductive particles include tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd ), Metals such as gallium (Ga) and thallium (Tl), and alloys of these metals.

In Patent Document 1, a resin heating step for heating the anisotropic conductive resin to a temperature higher than the melting point of the conductive particles and at which the curing of the resin component is not completed, and a resin component curing step for curing the resin component The electrical connection between the electrodes is described. Patent Document 1 describes that mounting is performed with the temperature profile shown in FIG. In Patent Document 1, the conductive particles melt in a resin component that is not completely cured at a temperature at which the anisotropic conductive resin is heated.

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

The following Patent Document 3 discloses a thermosetting resin composition containing solder particles, a thermosetting resin binder, and a flux component. In Patent Document 3, as the flux component, (1) a salt of dicarboxylic acid or tricarboxylic acid and diethanolamines or triethanolamine, and (2) addition of carboxylic acid anhydride with diethanolamines or triethanolamines The reactants are listed.

JP 2004-260131 A WO2008 / 023452A1 JP 2013-256484 A

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

An object of the present invention is a conductive material that has high storage stability and exhibits excellent solder cohesion even after being left standing for a long time after the conductive material is placed on the connection target member. Is to provide. Another object of the present invention is to provide a connection structure using the conductive material.

According to a wide aspect of the present invention, the outer surface portion of the conductive portion includes 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. In a conductive material at 25 ° C., a conductive material is provided in which the flux is present as a solid at 25 ° C.

In a specific aspect of the conductive material according to the present invention, the single flux is solid at 25 ° C. in a state where it is not mixed with the conductive particles and the thermosetting component.

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

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

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

In a specific aspect of the conductive material according to the present invention, the melting point of the flux is not lower than −50 ° C. of the solder in the conductive particles and not higher than + 50 ° C. of the solder in the conductive particles.

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

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

In a specific aspect of the conductive material according to the present invention, the flux is attached on the surface of the conductive particles.

In a specific aspect of the conductive material according to the present invention, the conductive particles have an average particle diameter of 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 a specific aspect of the conductive material according to the present invention, the conductive material is a conductive paste.

According to a wide 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 A connection portion connecting the second connection target member and the second connection target member, wherein the material of the connection portion is the conductive material described above, and the first electrode and the second electrode Is provided that is electrically connected by a solder part in the connection part.

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 the portion is viewed, 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 includes a plurality of conductive particles having solder on the outer surface portion of the conductive portion, a thermosetting component, and a flux, and the flux is a salt of an acid and a base, In the conductive material at 25 ° C., the flux is present as a solid, so that the storage stability of the conductive material can be improved, and the conductive material is placed on the connection target member and then left for a long time. Since it exhibits excellent solder cohesiveness, high conduction reliability can be expressed.

FIG. 1 is a cross-sectional view schematically showing a connection structure obtained using a conductive material according to an embodiment of the present invention. 2A to 2C are cross-sectional views for explaining each step of an example of a method for manufacturing a connection structure using a conductive material according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a modification 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 for the conductive material. FIG. 6 is a cross-sectional view showing a third example of conductive particles that can be used for the 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 part. The conductive particles have solder on the outer surface portion of the conductive portion. Solder is contained in the conductive part and is a part or all of the conductive part. The binder is a component excluding conductive particles contained in the conductive material.

The conductive material according to the present invention includes 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. Furthermore, in the conductive material according to the present invention, the flux exists in a solid state in a 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.

Note that whether or not the flux is solid in the conductive material at 25 ° C. can be determined as follows. In this specification, regarding a flux that is not liquid at 25 ° C., a flux that keeps its shape when a conductive material containing the flux at 25 ° C. is allowed to stand for 5 minutes is defined as a solid flux at 25 ° C. A flux that does not maintain its shape when a conductive material containing flux is allowed to stand for 5 minutes is defined as a semi-solid flux at 25 ° C. Also, the semi-solid flux at 25 ° C. is not included in the solid flux at 25 ° C.

In the present invention, since the above configuration is provided, the storage stability of the conductive material can be improved. Furthermore, since the present invention is provided with the above-described configuration, it exhibits excellent solder cohesion even after being left to stand for a long time after the conductive material is disposed on the connection target member. It can be expressed.

In the present invention, it is preferable that the single flux is solid at 25 ° C. without being mixed with the conductive particles and the thermosetting component. The flux alone before being mixed with the conductive particles and the thermosetting component is preferably solid at 25 ° C. In these cases, it is easy to cause the flux to exist as a solid in a conductive material at 25 ° C.

In addition, it can be judged as follows whether the said flux single-piece | unit is a solid at 25 degreeC. In this specification, regarding a flux that is not liquid at 25 ° C., a flux that keeps 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 at 25 ° C. A flux that does not retain its shape when allowed to stand for 5 minutes is defined as a semi-solid flux at 25 ° C. Also, the semi-solid flux at 25 ° C. is not included in the solid flux at 25 ° C.

When obtaining the connection structure, after arranging the conductive material on the first connection target member, the laminated body of the first connection target member and the conductive material has the second connection target member on the conductive material. May be temporarily stored before deployment. In this invention, even if the said laminated body is stored, the connection structure excellent in conduction | electrical_connection reliability can be obtained.

In the present invention, since the above-described 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, there is a tendency that the solder of the conductive particles is difficult to gather on the electrode, but in the present invention, the solder can be sufficiently gathered on the electrode even if the electrode width is narrow. In the present invention, since the above configuration is provided, when the electrodes are electrically connected, the solder in the conductive particles is easily located between the upper and lower electrodes, and the solder in the conductive particles is used as the electrode. (Line) can be arranged efficiently. In the present invention, when the electrode width is wide, the solder in the conductive particles is arranged more efficiently on the electrode.

Also, it is difficult for a part of the solder in the conductive particles to be arranged in a region (space) where no electrode is formed, and the amount of solder arranged in a region where no electrode is formed can be considerably reduced. In the present invention, the solder that is not located between the opposing electrodes can be efficiently moved between the opposing electrodes. Therefore, the conduction reliability between the electrodes can be improved. In addition, it is possible to prevent electrical connection between laterally adjacent electrodes that should not be connected, and to improve insulation reliability.

Furthermore, in this invention, the heat resistance of the hardened | cured material of an electroconductive material can be improved. In particular, when a conductive material is used for the optical semiconductor device, heat is generated during light irradiation, and a cured product of the conductive material is exposed to a high temperature. Since the conductive material according to the present invention is excellent in the heat resistance of a 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 is increased.

Furthermore, in the present invention, it is possible to prevent displacement between the electrodes. In the present invention, when the second connection target member is superimposed on the first connection target member having the conductive material disposed on the upper surface, the electrode of the first connection target member and the electrode of the second connection target member Even when the first connection target member and the second connection target member are overlapped in a state where the alignment of the first connection target member and the second connection target member are overlaid, the shift is corrected and the first connection target member electrode and the second connection target are corrected. The electrode of the member can be connected (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) at 25 ° C. of the conductive material is preferably 10 Pa · s or more, more preferably 50 Pa · s or more, and further preferably 100 Pa. · S or more, preferably 800 Pa · s or less, more preferably 600 Pa · s or less, and further 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 using, for example, an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) and the like at 25 ° C. and 5 rpm.

The conductive material can be used as a conductive paste and a conductive film. 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 preferably 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) acryl” means one or both of “acryl” and “methacryl”. “(Meth) acryloyl” means one or both of “acryloyl” and “methacryloyl”.

(Conductive particles)
The conductive particles electrically connect the electrodes of the connection target member. The conductive particles have solder on the outer surface portion of the conductive portion. The conductive particles may be solder particles formed by solder. The solder particles have solder on the outer surface portion of the conductive portion. As for the said solder particle, both the center part and the outer surface part of an electroconductive part are formed with the 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 conductive particles including base particles and conductive portions arranged on the surface of the base particles. The solder particles include, for example, solder preferably at 80% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more. The said electroconductive particle may have a base material particle and the electroconductive part arrange | positioned on the surface of this base material particle. In this case, the conductive particles have solder on the outer surface portion of the conductive portion.

Compared to the case where the above solder particles are used, in the case where conductive particles including base particles not formed by solder and solder portions arranged on the surface of the base particles are used, The conductive particles are less likely to collect on the surface, and the solder joint property between the conductive particles is low, so the conductive particles that have moved onto the electrodes tend to move out of the electrodes, and the effect of suppressing displacement between the electrodes Tend to be lower. Therefore, the conductive particles are preferably solder particles formed by solder.

From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, a carboxyl group or an amino group is present on the outer surface of the conductive particles (the outer surface of the solder). It is preferable that a carboxyl group is 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 particle (the 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). Bonding is preferred. 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 and the left end represent a binding site.

There are hydroxyl groups on the solder surface. 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 other coordination bond (chelate coordination) or the like, so the connection resistance between the electrodes is reduced, And the electroconductive particle which can suppress generation | occurrence | production of a void is obtained.

In the conductive particles, the bond form between the solder surface and the group containing a carboxyl group may not include a coordinate bond, and may not include a bond due to a chelate coordinate.

From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the conductive particle is a compound having a functional group capable of reacting with a hydroxyl group and a carboxyl group or an amino group ( Hereinafter, 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 using a compound X). In the above reaction, a covalent bond is formed. By causing the hydroxyl group on the surface of the solder to react with the functional group capable of reacting with the hydroxyl group in the compound X, solder particles in which a group containing a carboxyl group or an amino group is covalently bonded to the surface of the solder can be easily obtained. 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 a 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 preferred. The functional group capable of reacting with the hydroxyl group may be a hydroxyl group or a carboxyl group.

Examples of the compound 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-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid and dodecanedioic acid It is done. Glutaric acid or glycolic acid is preferred. Only 1 type may be used for the compound which has the functional group which can react with the said hydroxyl group, and 2 or more types may be used together. 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 solder surface. 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-mercaptoisobutyric acid , 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid and 4-phenylbutyric acid. Glutaric acid, adipic acid or glycolic acid is preferred. As for the compound which has the said flux effect | action, only 1 type may be used and 2 or more types may be used together.

From the viewpoint of effectively reducing 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 part of the carboxyl group of the compound having at least two carboxyl groups with the hydroxyl group on the surface of the solder, conductive particles in which the 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, using conductive particles and 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. 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.

Moreover, in the said manufacturing method of electroconductive particle, using electroconductive particle, this electroconductive particle, the compound which has the functional group and carboxyl group which can react with the said hydroxyl group, the said catalyst, and the said solvent are mixed, and it heats. It is preferable. By the mixing and heating step, 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, and more preferably toluene. As for the said solvent, only 1 type may be used and 2 or more types may be used together.

Examples of the catalyst include p-toluenesulfonic acid, benzenesulfonic acid, 10-camphorsulfonic acid, and the like. The catalyst is preferably p-toluenesulfonic acid. As for the said catalyst, only 1 type may be used and 2 or more types may be used together.

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

From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the conductive particles react with the isocyanate compound to the hydroxyl group on the surface of the solder using the isocyanate compound. It is preferable that it is obtained through the process 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, it is possible to easily obtain conductive particles in which the nitrogen atom of the group derived from the isocyanate group is covalently bonded to the surface of the solder. By reacting the isocyanate compound with a hydroxyl group on the surface of the solder, a group derived from an isocyanate group can be chemically bonded to the surface of the solder in the form of a covalent bond.

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

From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the compound having at least one carboxyl group preferably 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 on the surface of the solder, the surface of the solder is represented by the formula (X) by reacting the residual isocyanate group and a compound having reactivity with the residual isocyanate group and having a carboxyl group. A carboxyl group can be introduced through the group to be formed.

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

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

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, 4-amino Butyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecane Examples include acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid and dodecanedioic acid. . Glutaric acid, adipic acid or glycolic acid is preferred. As for the compound which has at least 1 said carboxyl group, only 1 type may be used and 2 or more types may be used together.

After reacting the isocyanate compound with the hydroxyl group on the surface of the solder using the isocyanate compound, the carboxyl group of the compound having a plurality of carboxyl groups is reacted with the hydroxyl group on the surface of the solder. The group containing can be left.

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

The following method can be given as a specific method for producing the conductive particles. Conductive particles are dispersed in an organic solvent, and a silane coupling agent having an isocyanate group is added. Thereafter, a silane coupling agent is covalently bonded to the surface of the solder using a reaction catalyst between a hydroxyl group and an isocyanate group on the surface of the solder of the conductive particles. Next, a hydroxyl group is produced | generated by hydrolyzing the alkoxy group couple | bonded with the silicon atom of a silane coupling agent. The produced hydroxyl group is reacted with a carboxyl group of a compound having at least one carboxyl group.

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

The reaction catalyst for hydroxyl groups and isocyanate groups on the surface of the solder of the conductive particles includes tin catalysts (dibutyltin dilaurate, etc.), amine catalysts (triethylenediamine, etc.), carboxylate catalysts (lead naphthenate, potassium acetate, etc.) And a trialkylphosphine catalyst (such as triethylphosphine).

From the viewpoint of effectively reducing 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 preferred. The compound represented by the following formula (1) has a flux action. Moreover, the compound represented by following formula (1) has a flux effect | action in the state introduced into the surface of 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. Examples of the compound represented by the above formula (1) include citric acid.

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

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

In the above formula (1B), R represents a divalent organic group having 1 to 5 carbon atoms. R in the above formula (1B) is the same as 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. A group represented by the following formula (2A) is preferably bonded to the surface of the solder, and more preferably a 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. R in the above formula (2A) is the same as R in the above formula (1).

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

From the viewpoint of enhancing the wettability of the solder surface, the molecular weight of the compound having at least one carboxyl group is preferably 10,000 or less, more preferably 1000 or less, and even more preferably 500 or less. From the viewpoint of suppressing migration more effectively and from the viewpoint of further effectively reducing 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. Further, when the compound having at least one carboxyl group is a polymer, it means a weight average molecular weight.

Since the cohesiveness of the conductive particles can be effectively increased at the time of conductive connection, the conductive particles may have a conductive particle main body and an anionic polymer disposed on the surface of the conductive particle main body. preferable. The conductive particles are preferably obtained by surface-treating the conductive particle body with an anionic polymer or a compound that becomes an anionic polymer. The conductive particles are preferably a surface treated product of an anionic polymer or a compound that becomes an anionic polymer. As for the said anion polymer and the compound used as the said anion polymer, only 1 type may respectively be used and 2 or more types may be used together. The anionic polymer is a polymer having an acidic group.

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

Examples of the anion portion 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 —), a sulfonate ion group (—SO ₃ ^—) ), And phosphate ion groups (—PO ₄ ⁻ ) and the like.

In addition, as another method of the surface treatment, a compound having a functional group that reacts with a hydroxyl group on the surface of the conductive particle main body and having a functional group that can be polymerized by addition or condensation reaction is used. The method of polymerizing on the surface of an electroconductive particle main body is mentioned. 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 the functional group that polymerizes by addition and condensation reactions includes a hydroxyl group, a carboxyl group, an amino group, and (meta ) An 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, 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 properties can be introduced on the surface of the conductive particles. Thereby, the cohesiveness of electroconductive particle can be effectively improved at the time of conductive connection, and the oxide film on the surface of an electrode can be effectively removed at the time of connection of the connection object member.

When the weight average molecular weight is not less than the above lower limit and not more than the above upper limit, it is easy to dispose an anionic polymer on the surface of the conductive particle main body, and effectively increase the cohesiveness of the conductive particles during conductive connection. And the conductive particles can be more efficiently arranged on the electrode.

The weight average molecular weight indicates a 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 conductive particle main body with a compound that becomes an anionic polymer is obtained by dissolving the solder in the conductive particles, and diluting the conductive particles with dilute hydrochloric acid that 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 introduction amount of the anionic polymer 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, more preferably 6 mgKOH or less.

The acid value can be measured as follows. 1 g of conductive particles is added to 36 g of acetone and dispersed with an ultrasonic wave for 1 minute. Thereafter, phenolphthalein is used as an indicator and titrated with a 0.1 mol / L potassium hydroxide ethanol solution.

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

FIG. 4 is a cross-sectional view showing a first example of conductive particles that can be used 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 base particles in the core and are not core-shell particles. As for the electroconductive particle 21, both the center part and the outer surface part of an electroconductive part are formed with the solder.

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

The electroconductive particle 31 shown in FIG. 5 is equipped with the base material particle 32 and the electroconductive part 33 arrange | positioned on the surface of the base material particle 32. FIG. 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 particle 32 is covered 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 are composed of the base particle 32, the second conductive portion 33A disposed on the surface of the base particle 32, and the solder portion 33B disposed on the outer surface of the second conductive portion 33A. With.

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 particle 31 has a two-layer structure. The conductive particle 41 shown in FIG. 6 has a solder part 42 as a single-layer conductive part. The conductive particles 41 include base particles 32 and solder portions 42 disposed on the surfaces of the base particles 32.

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

Various organic substances are suitably 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 polymethyl methacrylate and polymethyl acrylate; polycarbonate , Polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide , Polyacetal, polyimide, polyamideimide, polyether ether Tons, polyether sulfone, divinyl benzene polymer, and divinylbenzene copolymer, and the like. Examples of the divinylbenzene copolymer include divinylbenzene-styrene copolymer and 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 polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. It is preferably a coalescence.

When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group includes a non-crosslinkable monomer and And a crosslinkable monomer.

Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylate compounds such as meth) acrylate and isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate, etc. Oxygen atom-containing (meth) acrylate compounds; Nitrile-containing monomers such as (meth) acrylonitrile; Vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; Acids such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate Vinyl ester 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 chlorostyrene Etc.

Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol 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 acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) sia Silane-containing monomers such as rate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. Can be mentioned.

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 polymerizing by swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

When the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal, examples of inorganic substances for forming the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

When the substrate 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, the metal particles are preferably copper particles. However, the substrate particles are preferably not metal particles.

The method for forming the conductive part on the surface of the base particle and the method for forming the solder part on the surface of the base particle or the surface of the second conductive part are not particularly limited. Examples of the method for forming the conductive portion and the solder portion include a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, And a method of coating the surface of the substrate particles with a paste containing metal powder or metal powder and a binder. Electroless plating, electroplating or physical collision methods are preferred. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering. Further, in the method based on the physical collision, for example, a sheeter composer (manufactured by Tokuju Kogakusha Co., Ltd.) or the like is used.

The melting point of the substrate particles is preferably higher than the melting point of the solder part. The melting point of the substrate particles is preferably higher than 160 ° C, more preferably higher than 300 ° C, still more preferably higher than 400 ° C, and particularly preferably higher than 450 ° C. The melting point of the substrate particles may be less than 400 ° C. The melting point of the substrate particles may be 160 ° C. or less. The softening point of the substrate particles is preferably 260 ° C. or higher. The softening point of the substrate particles may be less than 260 ° C.

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

The solder is preferably a metal (low melting point metal) having a melting point of 450 ° C. or lower. The solder part 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 is 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. The solder in the conductive particles preferably contains tin. In 100% by weight of the metal contained in the solder part and 100% by weight of the metal contained in the solder in the conductive particles, the content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, and still more preferably. 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 not less than the above lower limit, the conduction reliability between the conductive particles and the electrode is further enhanced.

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

Using the conductive particles having the solder on the outer surface portion of the conductive portion, the solder is melted and joined to the electrodes, and the solder conducts between the electrodes. For example, since the solder and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, the use of conductive particles having solder on the outer surface of the conductive portion increases the bonding strength between the solder and the electrode, and as a result, the solder and the electrode are more unlikely to peel off, and the conduction reliability is effective. To be high.

The low melting point metal constituting the solder part 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 a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. 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 preferred are a tin-bismuth alloy and a tin-indium alloy.

The material constituting the solder (solder part) is preferably a filler material having a liquidus of 450 ° C. or lower based on JIS Z3001: Welding terms. 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 free of lead, is preferred. That is, the solder preferably does not contain lead, and is preferably a solder containing tin and indium or a solder containing tin and bismuth.

In order to further increase the bonding strength between the solder and the electrode, the solder in the conductive particles is nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese. Further, it may contain a metal such as chromium, molybdenum and palladium. Moreover, 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. 0.0001% by weight or more, preferably 1% by weight or less.

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

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

The second conductive part preferably contains a metal. The metal which comprises the said 2nd electroconductive part is not specifically 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. As for the said metal, only 1 type may be used and 2 or more types may be used together.

The second conductive part is preferably a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer or a gold layer, and even more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably have a nickel layer or a gold layer, and still more preferably have a copper layer. By using the conductive particles having these preferable conductive parts for the connection between the electrodes, the connection resistance between the electrodes is further reduced. Moreover, a solder part can be more easily formed on the surface of these preferable conductive parts.

The thickness of the solder part is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. When the thickness of the solder part is not less than the above lower limit and not more than the above upper limit, sufficient conductivity can be 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 part (total thickness of the conductive part) is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less, Especially preferably, it is 0.3 micrometer or less. The thickness of the conductive portion is the thickness of the entire conductive layer when the conductive portion is a multilayer. 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 hardened, and the conductive particles are sufficiently deformed when connecting the electrodes. .

When the conductive part 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 outermost conductive layer is not less than the above lower limit and not more than the above upper limit, the coating with the outermost conductive layer becomes uniform, corrosion resistance is sufficiently high, and the connection resistance between the electrodes is further increased. Lower. Further, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

The thickness of the conductive part 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 inspecting conductive particles. 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 through the vicinity of 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 is set to 50,000 times, 50 conductive particles are randomly selected, and the conductive portion of each conductive particle is observed. It is preferable to do. It is preferable to measure the thickness of the conductive part in the obtained conductive particles and arithmetically average it to obtain the thickness of the conductive part.

The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, preferably 100 μm or less, more preferably 50 μm or less, still more preferably 40 μm or less, 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 there are many solders in the conductive particles between the electrodes. It is easy to arrange and the conduction reliability is further enhanced.

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

In addition, the average particle diameter of electroconductive particle with the electroconductive particle single body before mixing with a thermosetting component and a flux, and the electroconductive particle in the electroconductive material after mixing with a thermosetting component and a flux. Are generally the same

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

The content of the conductive particles in 100% by weight of the conductive material is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, particularly preferably 20% by weight or more, 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 more solder in the conductive particles is arranged between the electrodes. It is easy to do and the conduction reliability is further increased. From the viewpoint of further improving the conduction reliability, the content of the conductive particles is preferably 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, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. From the viewpoint of further improving the curability and viscosity of the conductive material and further improving the conduction reliability and the connection reliability, an epoxy compound or an episulfide compound is preferable, and an epoxy compound is more preferable. The conductive material preferably contains an epoxy compound. As for the said thermosetting compound, only 1 type may be used and 2 or more types may be used together.

From the viewpoint of effectively increasing the heat resistance of the cured product and from the viewpoint of effectively lowering the dielectric constant of the cured product, the thermosetting compound preferably includes a thermosetting compound having a nitrogen atom. It is more preferable to include a thermosetting compound having a skeleton.

Examples of the thermosetting compound having a triazine skeleton include triazine triglycidyl ether and the like. PAS, TEPIC-VL, TEPIC-UC) and the like.

The above-mentioned epoxy compound includes an aromatic epoxy compound. Crystalline epoxy compounds such as resorcinol-type epoxy compounds, naphthalene-type epoxy compounds, biphenyl-type epoxy compounds, and benzophenone-type epoxy compounds are preferred. An epoxy compound that is solid at normal 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 preferable epoxy compound, the first connection target member and the second connection target are high when the connection target member is bonded to each other when the viscosity is high and acceleration is applied by impact such as conveyance. The positional deviation with respect to the member can be suppressed, and the viscosity of the conductive material can be greatly reduced by the heat at the time of curing, so that the aggregation of the solder can proceed efficiently.

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. More preferably, it is 98 weight% or less, More preferably, it is 90 weight% or less, Most preferably, it is 80 weight% or less. From the viewpoint of further improving the impact resistance, it is preferable that the content of the thermosetting compound is large.

(Thermosetting agent)
The thermosetting agent thermosets the thermosetting compound. Examples of the thermosetting 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, and a thermal radical generator. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

The imidazole curing agent is not particularly limited, and 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'-methylimidazolyl- (1')]-ethyl-s- Examples include triazine isocyanuric acid adducts.

The thiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-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, and preferably 12 or less. The solubility parameter is calculated by the Fedors method. For example, the solubility parameter of trimethylolpropane tris-3-mercaptopropionate is 9.6, and the solubility parameter of dipentaerythritol hexa-3-mercaptopropionate is 11.4.

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

Examples of the thermal cation initiator include iodonium cation curing agents, oxonium cation curing agents, and sulfonium cation curing agents. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-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). Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature of the thermosetting agent is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, still more preferably 80 ° C. or higher, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, still more preferably 150 ° C. Hereinafter, 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. The reaction initiation temperature of the thermosetting agent is particularly preferably 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 initiation temperature of the thermosetting agent is preferably higher than the melting point of the solder in the conductive particles, and is preferably 5 ° C. or higher. Is more preferable, and higher by 10 ° C. or more is more preferable.

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

The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent with respect to 100 parts by weight of the thermosetting compound is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, more preferably 75 parts by weight or less. When the content of the thermosetting agent is not less than 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 is difficult for an excess thermosetting agent that did not participate in curing after curing to remain, and the heat resistance of the cured product is further enhanced.

(flux)
The conductive material includes a flux. By using the flux, the solder in the conductive particles can be more effectively arranged on the electrode. Moreover, in this invention, the said flux is a combination of the acid which has the effect which wash | cleans the surface of a metal, and the base which has the effect | action which neutralizes the acid, and is a salt of these acids and a base.

When the above-mentioned flux, which is a salt of this specific acid and base, is solid at 25 ° C., the storage stability of the conductive material increases, and after the conductive material is placed on the connection target member, it is left for a long time. Since it exhibits excellent solder cohesiveness, a conductive material that can exhibit high conduction reliability can be provided. The flux is preferably a salt of an acid and a base and is solid at 25 ° C.

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

In addition, the storage stability of the conductive material is effectively increased, and after the conductive material is disposed on the connection target member, it exhibits excellent solder cohesion even when left for a long time, and exhibits high conduction reliability. Therefore, the above-mentioned flux which is a salt of a specific acid and base is preferably solid at 25 ° C. As for the said flux, only 1 type may be used and 2 or more types may be used together.

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

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

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. In order to facilitate the formation of a salt, the organic compound having the acid and the carboxyl group preferably has an alkyl group, and the total number of carbon atoms of the alkyl group and the carboxyl group is preferably 4 or more, preferably Is 8 or less.

In order to obtain the above reaction product, an ester of carboxylic acid may be used. Examples of carboxylic acid esters include alkyl esters of the above carboxylic acids. Examples of the alkyl group of the alkyl ester of the carboxylic acid include an alkyl group having 1 to 4 carbon atoms, and the carbon number of the alkyl group is preferably 3 or less, more preferably 2 or less.

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

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

The active temperature (melting point) of the flux is preferably 40 ° C. or higher, more preferably 50 ° C. or higher. Storage stability becomes still higher that the active temperature of the said flux is more than the said minimum.

From the viewpoint of more efficiently disposing the solder in the conductive particles on the electrode, the melting point of the flux is preferably the melting point of the solder in the conductive particles −50 ° C. or more, more preferably the solder melting point in the conductive particles. The melting point is −30 ° C. or more, preferably the melting point of the solder in the conductive particles + 50 ° C. or less, more preferably the melting point of the solder in the conductive particles + 30 ° C. or less, more preferably less than the melting point of the solder in the conductive particles. is there. When the melting point of the flux is not less than the above lower limit and not more than the above 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, more preferably 5 ° C. or more, More preferably, it is 10 ° C. or lower.

The flux may be dispersed in the conductive material or may be adhered on the surface of the conductive particles.

In the conductive material at 25 ° C., the above flux exists as a solid. When the flux is added in a state of being uniformly dissolved in the conductive material, the viscosity of the conductive material may increase due to a partial reaction between the thermosetting component and the flux. In addition, when a conductive material is placed on the connection target member 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 moisture in the air, or the flux and the solder In some cases, metal ions are generated by the reaction with the surface of the solder, which adversely affects the cohesiveness of the solder and the insulation between adjacent electrodes. On the other hand, if the flux is solid in a conductive material at 25 ° C, only the surface of the flux needs to be affected by the above, so it has high storage stability, high conductivity even after standing for a long time, and insulation. Sex can be expressed.

Further, in the conductive material at 25 ° C., the flux exists in a solid state, and when the flux is dissolved at a temperature lower than the melting point of the solder, when the conductive material is a paste, at room temperature (23 ° C.) Thixotropic properties can be imparted to the conductive material. Thereby, sedimentation of conductive particles can be prevented, shape retention after application can be exhibited, and the outflow of the conductive material to unnecessary portions can be further prevented. When the conductive material is a film, since the flux is solid, the liquid content in the conductive material can be reduced, so that the cutability of the film can be improved, and bleeding from the cut surface is suppressed. can do.

Further, when the flux is melted at a temperature lower than the melting point of the solder, since the flux is melted at the melting point of the solder, the melt viscosity of the conductive material is sufficiently lowered, and the solder cohesion is further improved. be able to.

Further, when the flux is melted at a temperature lower than the melting point of the solder, the flux is dissolved in the thermosetting compound or the thermosetting agent above the melting point of the solder, and further, the thermosetting compound or the thermosetting agent. The flux component is taken into the curing system by the reaction between the carboxyl group and amino group of the flux. Thereby, high insulation between adjacent electrodes can be expressed, and further corrosion of the electrodes can be prevented.

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

The “average particle size” of the flux indicates the number average particle size. The average particle diameter 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.

Note that there is a difference in the average particle diameter of the flux between 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. 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 diameter of the flux to the average particle diameter of the conductive particles (average particle diameter of the flux / average particle diameter of the conductive particles) is preferably 3 or less, more preferably Is 1 or less, more preferably 0.2 or less. When the ratio is less than or equal to the upper limit, the flux can be effectively brought into contact with the conductive particles, and the flux performance during heating can be further enhanced. For the same reason, the above ratio (average particle diameter of flux / average particle diameter of conductive particles) is preferably 0.005 or more, more preferably 0.01 or more, and further 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, more preferably 25% by weight or less.

(Insulating particles)
From the viewpoint of controlling the interval between the connection target members connected by the cured material of the conductive material and the interval between the connection target members connected by the solder in the conductive particles with high accuracy, the conductive material is made of insulating particles. It is preferable to contain. 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 away from the conductive particles.

The average particle diameter of the insulating particles is preferably 10 μm or more, more preferably 20 μm or more, further preferably 25 μm or more, preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 50 μm or less. When the average particle diameter of the insulating particles is not less than the above lower limit and not more than the above upper limit, the interval between the connection target members connected by the cured material of the conductive material, and between the connection target members connected by the solder in the conductive particles The interval becomes even more moderate.

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

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 diameter of the insulating particles is generally the same.

The material for the insulating particles includes an insulating resin and an insulating inorganic substance. As said insulating resin, the said resin quoted as resin for forming the resin particle which can be used as a base particle is mentioned. As said insulating inorganic substance, the said inorganic substance quoted as an inorganic substance for forming the inorganic particle which can be used as a base particle is mentioned.

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 thermoplastic resins, heat Examples thereof include curable resins and water-soluble resins.

Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylate 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. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose. Of these, water-soluble resins are preferable, and polyvinyl alcohol is more preferable.

In 100% by weight of the conductive material, the content of the insulating particles is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 10% by weight or less, more preferably 5% by weight. It is as follows. The conductive material may not contain insulating particles. When the content of the insulating particles is not less than the above lower limit and not more than the above upper limit, the interval between the connection target members connected by the cured material of the conductive material, and the interval between the connection target members connected by the solder in the conductive particles Becomes even more reasonable.

(Other ingredients)
The conductive material may be, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, and a lubricant as necessary. In addition, various additives such as an antistatic agent and a flame retardant may be included.

(Connection structure and method of manufacturing connection structure)
A 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 The connection object member and the connection part which has connected the said 2nd connection object member are provided. In the connection structure according to the present invention, the material of the connection portion is the conductive material described above, and the connection portion is formed of the conductive material described above. 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 the step of disposing the conductive material on the surface of the first connection target member having at least one first electrode on the surface, using the conductive material described above, A second connection target member having at least one second electrode on the surface opposite to the first connection target member side of the material, the first electrode and the second electrode A step of arranging the first connection target member and the second connection target member by connecting the first connection target member and the second connection target member by heating the conductive material to a temperature equal to or higher than the melting point of the solder in the conductive particles. Forming a portion with a cured product of the conductive material, and electrically connecting the first electrode and the second electrode with a solder portion in the connection portion. Preferably, the conductive material is heated above the curing temperature of the thermosetting component and the thermosetting compound.

In the connection structure according to the present invention and the method for manufacturing the connection structure, since a specific conductive material is used, solder in a plurality of conductive particles easily collects between the first electrode and the second electrode. The solder can be efficiently arranged on the electrode (line). In addition, a part of the solder is difficult to be disposed in a region (space) where no electrode is formed, and the amount of solder disposed in a region where no electrode is formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, it is possible to prevent electrical connection between laterally adjacent electrodes that should not be connected, and to improve insulation reliability.

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

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

In the method for manufacturing a connection structure according to the present invention, in the step of arranging the second connection target member and the step of forming the connection portion, no pressure is applied, and the second connection is applied to the conductive material. The weight of the target member is added, or pressure is applied in at least one of the step of arranging the second connection target member and the step of forming the connection portion, and the second connection target member It is preferable that the pressure of pressurization is less than 1 MPa in both the step of disposing and the step of forming the connecting 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 the warpage of the connection target member, in the method for manufacturing a connection structure according to the present invention, at least one of the step of arranging the second connection target member and the step of forming the connection portion is performed. The pressure of pressurization may be less than 1 MPa in both the step of performing pressure and arranging the second connection target member and the step of forming the connection portion. When pressurization is performed, the pressurization may be performed only in the step of arranging the second connection target member, or the 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 case where the pressure is less than 1 MPa includes the case where no pressure is applied. When pressurizing, the pressure of pressurization is preferably 0.9 MPa or less, more preferably 0.8 MPa or less. When the pressure of the pressurization is 0.8 MPa or less, the aggregation of the solder in the conductive particles is further promoted more remarkably than when the pressure of the pressurization exceeds 0.8 MPa.

In the method for manufacturing a connection structure according to the present invention, in the step of arranging the second connection target member and the step of forming the connection portion, no pressure is applied, and the second connection is applied to the conductive material. The weight of the target member is preferably 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 weight force of the second connection target member. It is preferable that no pressure is applied. In these cases, the uniformity of the amount of solder can be further enhanced in the plurality of solder portions. Furthermore, the thickness of the solder portion can be increased more effectively, and a large amount of solder in a plurality of conductive particles tends to gather between the electrodes, and the solder in the plurality of conductive particles is more efficiently distributed on the electrode (line). Can be arranged. In addition, it is difficult for a part of the solder in the plurality of conductive particles to be disposed in the region (space) where the electrode is not formed, and the amount of solder in the conductive particle disposed in the region where the electrode is not formed is further increased. Can be reduced. Therefore, the conduction reliability between the electrodes can be further enhanced. In addition, the electrical connection between the laterally adjacent electrodes that should not be connected can be further prevented, and the insulation reliability can be further improved.

Furthermore, in the step of arranging the second connection target member and the step of forming the connection portion, if the weight of the second connection target member is added to the conductive material without applying pressure, the connection portion is Solder arranged in a region (space) where no electrode is formed before it is formed is more likely to gather between the first electrode and the second electrode, and solder in a plurality of conductive particles can be The present inventors have also found that it can be arranged 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 used in combination. This has a great meaning in order to obtain the effects of the present invention at a higher level.

In addition, WO2008 / 023452A1 describes that it is preferable to pressurize with a predetermined pressure at the time of bonding from the viewpoint of efficiently moving the solder powder to the electrode surface, and the pressurizing pressure further ensures the solder area. For example, it is described that the pressure is set to 0 MPa or more, preferably 1 MPa or more. Further, even if the pressure intentionally applied to the adhesive tape is 0 MPa, the member disposed on the adhesive tape It is described that a predetermined pressure may be applied to the adhesive tape by its own weight. In WO2008 / 023452A1, it is described that the pressure applied intentionally to the adhesive tape may be 0 MPa, but there is no difference between the effect when the pressure exceeding 0 MPa is applied and when the pressure is set to 0 MPa. Not listed. In addition, WO2008 / 023452A1 recognizes nothing about the importance of using a paste-like conductive paste instead of a film.

Also, if a conductive paste is used instead of a conductive film, it becomes easy to adjust the thicknesses of the connection part and the solder part depending on the amount of the conductive paste applied. On the other hand, in the conductive film, in order to change or adjust the thickness of the connection portion, it is necessary to prepare a conductive film having a different thickness or to prepare a conductive film having a predetermined thickness. There is. Moreover, in the conductive film, compared with the conductive paste, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder, and the aggregation of the solder tends to be 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 using a conductive material according to an embodiment of the present invention.

The connection structure 1 shown in FIG. 1 is a connection that connects a first connection target member 2, a second connection target member 3, and the first connection target member 2 and the second connection target member 3. Part 4. The connection part 4 is formed of the conductive material described above. In the present embodiment, the conductive material includes solder particles as conductive particles.

The connecting portion 4 includes a solder portion 4A in which a plurality of solder particles are gathered and joined to each other, and a cured product portion 4B in which a thermosetting component is thermally cured. In the present embodiment, solder particles are used as the conductive particles in order to form the solder portion 4A. In the solder particles, both the central portion and the outer surface of the conductive portion are formed of solder.

The first connection object 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 connection portion 4, no solder exists 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 an area different from the solder part 4A (hardened product part 4B part), there is no solder separated from the solder part 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 gather between the first electrode 2 a and the second electrode 3 a, and after the plurality of solder particles melt, After the electrode surface wets and spreads, it solidifies to form the solder portion 4A. For this reason, the connection area of 4 A of solder parts and the

1st electrode

2a, and 4 A of solder parts, and the 2nd electrode 3a becomes large. That is, by using solder particles, the solder portion 4A, the first electrode 2a, and the solder as compared with the case where the outer surface portion of the conductive portion is made of conductive particles such as nickel, gold or copper are used. The contact area between the portion 4A and the second electrode 3a increases. For this reason, the conduction | electrical_connection reliability and connection reliability in the connection structure 1 become high.

In addition, in the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in the facing region between the first and

second electrodes

2a and 3a. The connection structure 1X of the modification shown in FIG. 3 is different from the connection structure 1 shown in FIG. 1 only in the connection portion 4X. The connection part 4X has the solder part 4XA and the hardened | cured material part 4XB. As in the connection structure 1X, most of the solder portions 4XA are located in regions where the first and

second electrodes

2a and 3a are opposed to each other, and a part of the solder portion 4XA is first and second. You may protrude to the side from the area | region which

electrode

2a, 3a has opposed. The solder part 4XA protruding laterally from the region where the first and

second electrodes

2a and 3a are opposed is a part of the solder part 4XA and is not a solder separated from the solder part 4XA. In the present embodiment, the amount of solder away from the solder portion can be reduced, but the solder away from the solder portion may exist in the cured product portion.

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

From the viewpoint of further improving the conduction reliability, in the

connection structures

1 and 1X, the first electrode 2a and the second electrode 2a are arranged in the stacking direction of the first electrode 2a, the

connection portions

4 and 4X, and the second electrode 3a. When the portion facing the electrode 3a is viewed, 50% or more (more preferably 60% or more, more preferably) of the 100% area of the portion facing the first electrode 2a and the second electrode 3a. The solder portions 4A and 4XA in the

connection portions

4 and 4X are preferably disposed at 70% or more, particularly preferably 80% or more, and most preferably 90% or more.

From the viewpoint of further improving the conduction reliability, the portion where 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 is seen. Sometimes, 50% or more (more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more) out of 100% of the area where the first electrode and the second electrode face each other. , Most preferably 90% or more), the solder portion in the connection portion is preferably disposed.

From the viewpoint of further improving the conduction reliability, the first electrode and the second electrode are opposed to each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode. When the matching portion is viewed, 60% or more (more preferably 70% or more, still more preferably 80%) of the solder portion in the connection portion is formed on the facing portion of 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 including a thermosetting component 11B, a plurality of solder particles 11A, and a specific flux is disposed on the surface of the first connection target member 2. (First step). The used conductive material contains a thermosetting compound and a thermosetting agent as the thermosetting component 11B.

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

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

Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B, in the conductive material 11 on the surface of the first connection target member 2, on the surface opposite to the first connection target member 2 side of the conductive material 11, The 2nd connection object member 3 is arrange | positioned (2nd process). On the surface of the conductive material 11, the second connection target member 3 is disposed from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

Next, the conductive material 11 is heated to a temperature equal to or higher than 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 that existed in the region where no electrode is formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). When the 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. Also, the solder particles 11A are melted and joined together. Further, the thermosetting component 11B is thermoset. As a result, as shown in FIG. 2C, the connection portion 4 that connects the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connection part 4 is formed of the conductive material 11, the solder part 4A is formed by joining a plurality of solder particles 11A, and the cured part 4B is formed by thermosetting the thermosetting component 11B. If the solder particles 11A are sufficiently moved, the first electrode 2a and the second electrode are moved after the movement of the solder particles 11A not located between the first electrode 2a and the second electrode 3a starts. It is not necessary to keep the temperature constant until the movement of the solder particles 11A is completed.

In this embodiment, it is preferable that no pressure is applied in the second step and the third step. In this case, the weight of the second connection target member 3 is added to the conductive material 11. For this reason, when the connection part 4 is formed, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. In addition, if pressure is applied in at least one of the second step and the third step, the action of the solder particles trying to collect between the first electrode and the second electrode is hindered. The tendency to become higher.

Moreover, in this embodiment, since pressurization is not performed, when the second connection target member is superimposed on the first connection target member to which the conductive material is applied, the electrode of the first connection target member Even when the first connection target member and the second connection target member are overlapped in a state where the alignment of the electrodes of the second connection target member is shifted, the shift is corrected and the first connection target member is corrected. Can be connected to the electrode of the second connection target member (self-alignment effect). This is because the molten solder self-aggregated 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. As the area where the solder and the other components of the conductive material are in contact with each other is minimized, the energy becomes more stable. Therefore, the force that makes the connection structure with alignment, which is the connection structure with the smallest area, works. Because. At this time, it is desirable that the conductive material is not cured, and that the viscosity of components other than the conductive particles of the conductive material is sufficiently low at that 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 performed continuously. Moreover, after performing the said 2nd process, the laminated body of the 1st connection object member 2, the electrically-conductive material 11, and the 2nd connection object member 3 which are obtained is moved to a heating part, and the said 3rd connection object is carried out. You may perform a process. In order to perform the heating, the laminate may be disposed on a heating member, or the laminate may be disposed in a heated space.

The heating temperature in the third step is preferably 140 ° C. or higher, more preferably 160 ° C. or higher, preferably 450 ° C. or lower, more preferably 250 ° C. or lower, and 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 above the melting point of the solder and the curing temperature of the thermosetting compound, or a connection structure The method of heating only the connection part of these is mentioned.

Examples of instruments used in the method of locally heating include a hot plate, a heat gun that applies hot air, a soldering iron, and an infrared heater.

In addition, when heating locally with a hot plate, the metal directly under the connection is made of a metal with high thermal conductivity, and other places where heating is not preferred are made of a material with low thermal conductivity such as a fluororesin. The upper surface of the hot plate is preferably formed.

The first and second connection target members are not particularly limited. Specifically as said 1st, 2nd connection object member, electronic components, such as a semiconductor chip, a semiconductor package, LED chip, LED package, a capacitor | condenser, a diode, and a resin film, a printed circuit board, a flexible printed circuit board, flexible Examples thereof include electronic components such as circuit boards such as flat cables, rigid flexible boards, glass epoxy boards, and glass boards. The first and second connection target members are preferably electronic components.

At least one of the first connection target member and the second connection target member is preferably a semiconductor chip, a resin film, a flexible printed circuit board, a rigid flexible circuit board, or a flexible flat cable. A substrate, a flexible flat cable, or a rigid flexible substrate is more preferable. The second connection target member is preferably a semiconductor chip, a resin film, a flexible printed board, a rigid flexible board, or a flexible flat cable, and more preferably a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. preferable. Resin films, flexible printed boards, flexible flat cables, and rigid flexible boards have the property of being highly flexible and relatively lightweight. When a conductive film is used for the connection of such connection target members, the solder in the conductive particles tends not to collect on the electrodes. On the other hand, by using a conductive paste, even if a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board is used, the solder in the conductive particles can be efficiently collected on the electrodes, The conduction reliability can be sufficiently increased. When using a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible circuit board, compared to the case of using other connection target members such as a semiconductor chip, the conduction reliability between the electrodes by not applying pressure is improved. The improvement effect can be obtained more effectively.

Peripherals, area arrays, etc. exist in the form of the connection target member. 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, there are electrodes in the plane.

Examples of the electrode provided on the connection target member include metal electrodes such as 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 tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal 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 only to the following examples.

Thermosetting compound 1: Resorcinol type epoxy compound, “Epolite TDC-LC” manufactured by Kyoeisha Chemical, 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: Trimethylolpropane tris (3-mercaptopropinate), “TMMP” manufactured by SC Organic Chemical Co., Ltd.

Thermosetting agent 2: Todipentaerythritol hexakis (3-mercaptopropionate), “DPMP” manufactured by SC Organic Chemical Co., Ltd.

Latent epoxy thermosetting agent 1: T & K TOKA's “Fujicure 7000”

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

Preparation method of flux 2:
The white crystals obtained by the same method as in flux 1 were pulverized in a mortar until the average particle size became 10 μm, and flux 2 was obtained.

Preparation method of flux 3:
The white crystals obtained by the same method as in flux 1 were pulverized in a mortar until the average particle size became 1 μm, and flux 3 was obtained.

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

Method for producing flux 5:
A three-necked flask was charged with 160 g of acetone and 31 g of cyclohexanecarboxylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and dissolved at room temperature until uniform. Thereafter, 24 g of cyclohexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 30 minutes, and the mixture was stirred at room temperature for 2 hours after completion of the addition. Precipitated white crystals were collected by filtration, washed with acetone, and vacuum dried. Then, it grind | pulverized until the average particle diameter was set to 10 micrometers in the mortar, and the flux 5 was obtained.

Method for producing flux 6:
A three-necked flask was charged with 160 g of acetone and 35 g of adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and dissolved at room temperature until uniform. Thereafter, 26 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 30 minutes, and the mixture was stirred at room temperature for 2 hours after completion of the addition. Precipitated white crystals were collected by filtration, washed with acetone, and vacuum dried. Then, it grind | pulverized until the average particle diameter was set to 10 micrometers in the mortar, and the flux 6 was obtained.

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

Production method of 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 resulting glutaric acid triethanolamine salt was a semi-solid at 25 ° C.

In addition, regarding the solid flux 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. 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 Kinzoku Co., Ltd., average particle diameter (median diameter 12 μm))

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

Method for producing solder particles 3:
A three-necked flask was charged with 160 g of acetone and 32 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) and dissolved at room temperature until uniform. Then, after putting 100 g of solder particles 1 and stirring for 15 minutes, 26 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 30 minutes. A flux was deposited on the surface. Thereafter, the solder particles were washed once with acetone and vacuum dried to obtain solder particles 3.

(Examples 1 to 17 and Comparative Examples 1 and 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 to obtain anisotropic conductive pastes. In the obtained anisotropic conductive paste, the flux was present in the states shown in Tables 1 and 2.

(2) Production of connection structure (area array) As a first connection target member, a copper electrode having a diameter of 250 μm and a thickness of 10 μm at a pitch of 400 μm is provided on the surface of a semiconductor chip body (size 5 × 5 mm, thickness 0.4 mm). A semiconductor chip arranged in an area array was prepared. The number of copper electrodes is 10 × 10 in total per 100 semiconductor chips.

As the second connection target member, the same pattern is formed on the surface of the glass epoxy substrate 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 gold electrode was disposed and a solder resist film was formed in a region where the gold electrode was not disposed. The level difference between the surface of the copper electrode and the surface of the solder resist film is 15 μm, and the solder resist film protrudes from the copper electrode.

The anisotropic conductive paste immediately after fabrication 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 leaving at 23 ° C. and 50% RH for 2 hours, a semiconductor chip was 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 this state, the temperature of the anisotropic conductive paste layer was changed to the solder melting point (139 ° C. in Examples 1 to 9, 12 to 17 and Comparative Examples 1 and 2, and in Examples 10 and 11 after 5 seconds from the start of temperature increase. 217 ° C.). Further, 15 seconds after the start of temperature increase, the temperature of the anisotropic conductive paste layer was the melting point of the solder + 21 ° C. (160 ° C. in Examples 1 to 9, 12 to 17 and Comparative Examples 1 and 2, and in Examples 10 and 11. The anisotropic conductive paste layer was cured by heating to 238 ° C. and holding for 5 minutes to obtain a connection structure. No pressure was applied during heating.

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

(2) Storage stability The anisotropic conductive paste was put into a syringe and stored at 23 ° C. for 24 hours. After storage, the viscosity (η25) at 25 ° C. of the anisotropic conductive paste was measured under the conditions of 25 ° C. and 5 rpm using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.). Storage stability was determined 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 ○○, viscosity after storage is within ± 50% of viscosity before storage Δ: Standard of ○○ 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 part By observing a cross section of the obtained connection structure, the thickness of the solder part located between the upper and lower electrodes was evaluated.

(4) Solder placement accuracy on electrode 1
In the obtained connection structure, when the portion where 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 is viewed, The ratio X of the area where the solder part in the connection part is arranged in the area of 100% of the part facing the second electrode was evaluated. The solder placement accuracy 1 on the electrode was determined according to the following criteria.

[Criteria for solder placement accuracy 1 on electrode]
○○: 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% X: Ratio X is less than 50%

(5) Solder placement accuracy on electrode 2
In the obtained connection structure, when the portion where the first electrode and the second electrode face each other in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is seen, The ratio Y of the solder part in the connection part arrange | positioned in the part which the 1st electrode and 2nd electrode oppose in 100% of solder parts in a part was evaluated. The solder placement accuracy 2 on the electrode was determined according to the following criteria.

[Criteria for solder placement accuracy 2 on electrode]
◯: Ratio Y is 99% or more ○: Ratio Y is 90% or more and less than 99% △: Ratio Y is 70% or more and less than 90% X: Ratio Y is less than 70%

(6) Electrical connection reliability between upper and lower electrodes In the obtained connection structure (n = 15), the connection resistance per connection portion between the upper and lower electrodes was measured by a four-terminal method. The average value of connection resistance was calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. The conduction reliability was determined according to the following criteria. However, when even one of n = 15 was not conductive between the upper and lower electrodes, it was determined as “x”.

[Judgment criteria for conduction reliability]
◯: Average connection resistance is 50 mΩ or less ○: Average connection resistance exceeds 50 mΩ, 70 mΩ or less △: Average connection resistance exceeds 70 mΩ, 100 mΩ or less ×: Average connection resistance exceeds 100 mΩ Or there is a bad connection

(7) Insulation reliability between electrodes adjacent in the horizontal direction In the obtained connection structure (n = 15), after leaving in an atmosphere of 85 ° C. and 85% humidity for 100 hours, between the electrodes adjacent in the horizontal direction Then, 15V was applied, and the resistance value was measured at 25 locations. Insulation reliability was judged according to the following criteria. However, when even one of n = 15 electrodes is electrically connected in the horizontal direction, it was determined as “x”.

[Criteria for insulation reliability]
○○○: The average value of connection resistance is 10 ¹⁴ Ω or more ○○: The average value of connection resistance is 10 ⁸ Ω or more and less than 10 ¹⁴ Ω ○: The average value of connection resistance is 10 ⁶ Ω or more and less than 10 ⁸ Ω : The average value of the connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω ×: The average value of the connection resistance is less than 10 ⁵ Ω

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

DESCRIPTION OF

SYMBOLS

1,1X ... Connection structure 2 ... 1st connection object member 2a ... 1st electrode 3 ... 2nd connection object member 3a ...

2nd electrode

4, 4X ... Connection part 4A, 4XA ... Solder part 4B, 4XB ... Cured part 11 ... Conductive material 11A ... Solder particles (conductive particles)
11B ... thermosetting component 21 ... conductive particles (solder particles)
31 ... Conductive particles 32 ... Base particle 33 ... Conductive part (conductive part having solder)
33A ... second conductive part 33B ... solder part 41 ... conductive particles 42 ... solder part

Claims

A plurality of conductive particles having solder on the outer surface portion of the conductive portion,
A thermosetting component;
Including flux,
The flux is a salt of an acid and a base;
A conductive material in which the flux exists as a solid in a conductive material at 25 ° C.
The conductive material according to claim 1, wherein the flux alone is solid at 25 ° C in a state where it is not mixed with the conductive particles and the thermosetting component.
The conductive material according to claim 1 or 2, wherein the flux is a salt of an organic compound having a carboxyl group and an organic compound having an amino group.
The conductive material according to any one of claims 1 to 3, wherein an average particle size of the flux is 30 µm or less.
5. The conductive material according to claim 1, wherein a ratio of an average particle size of the flux to an average particle size of the conductive particles is 3 or less.
6. The conductive material according to claim 1, wherein the melting point of the flux is not lower than −50 ° C. of the solder in the conductive particles and not higher than 50 ° C. of the solder in the conductive particles.
The conductive material according to any one of claims 1 to 6, wherein the conductive particles are solder particles.
The conductive material according to any one of claims 1 to 7, wherein the thermosetting component includes a thermosetting compound having a triazine skeleton.
The conductive material according to any one of claims 1 to 8, wherein the flux adheres on the surface of the conductive particles.
The conductive material according to any one of claims 1 to 9, wherein an average particle diameter of the conductive particles is 1 µm or more and 40 µm or less.
11. The conductive material according to claim 1, wherein a 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 11, which is a conductive paste.
A first connection target member having at least one first electrode on its surface;
A second connection target member having at least one second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The material of the connection part is the conductive material according to any one of claims 1 to 12,
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 first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode 14. The connection structure according to claim 13, wherein the solder portion in the connection portion is arranged in 50% or more of 100% of the area facing the two electrodes.