KR102569944B1 - Electroconductive material and connection structure - Google Patents

Abstract

A conductive material capable of efficiently disposing solder in conductive particles on an electrode even when the width of the electrode is narrow, and improving conduction reliability is provided. The conductive material according to the present invention contains a plurality of conductive particles having solder on the outer surface portion of the conductive portion, a thermosetting compound, a thiol curing agent, and an amine curing agent.

Description

Conductive material and connection structure {ELECTROCONDUCTIVE MATERIAL AND CONNECTION STRUCTURE}

The present invention relates to a conductive material containing conductive particles with solder. Further, the present invention relates to a connection structure using the above conductive material.

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

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

When electrically connecting an electrode of a flexible printed circuit board and an electrode of a glass epoxy substrate by means of the anisotropic conductive material, for example, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. Next, a flexible printed circuit board is laminated, heated and pressed. In this way, the anisotropic conductive material is cured and electrically connected between the electrodes through the conductive particles to obtain a bonded structure.

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

In Patent Document 1, through a resin heating step of heating an anisotropic conductive resin to a temperature higher than the melting point of the conductive particles and at which curing of the resin component is not completed, and a resin component curing step of curing the resin component, Electrical connection between the electrodes is described. Further, Patent Literature 1 describes mounting with the temperature profile shown in FIG. 8 of Patent Literature 1. In Patent Literature 1, conductive particles are melted in a resin component at which an anisotropic conductive resin is heated at a temperature where curing is not completed.

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

Further, in Patent Document 3 described below, a semiconductor chip having a plurality of connection terminals is disposed facing a wiring board having a plurality of electrode terminals, and the electrode terminals of the wiring board and the connection terminals of the semiconductor chip are electrically connected. A method of mounting a flip chip that is connected to is disclosed. In this flip chip mounting method, a resin composition containing solder powder and a convection additive is used.

Japanese Unexamined Patent Publication No. 2004-260131 WO2008/023452A1 Japanese Unexamined Patent Publication No. 2006-114865

In the conventional anisotropic conductive paste containing solder powder or conductive particles having a solder layer on the surface, the solder powder or conductive particles may not be efficiently disposed on an electrode (line). In conventional solder powder or conductive particles, the moving speed of the solder powder or conductive particles onto the electrode may be slow.

Further, when electrodes are electrically connected by the method described in Patent Literature 1 using the anisotropic conductive material described in Patent Literature 1, conductive particles containing solder may not be efficiently disposed on the electrode (line). . Further, in the examples of Patent Literature 1, the temperature is maintained at a constant temperature in order to sufficiently move the solder at a temperature equal to or higher than the melting point of the solder, which lowers the manufacturing efficiency of the bonded structure. When mounting is performed with the temperature profile described in FIG. 8 of Patent Document 1, the manufacturing efficiency of the bonded structure is lowered.

In addition, the adhesive tape described in Patent Literature 2 is in the form of a film and is not in the form of a paste. In an adhesive tape having a composition as described in Patent Literature 2, it is difficult to efficiently dispose solder powder on electrodes (lines). For example, in the adhesive tape described in Patent Literature 2, a part of the solder powder tends to be disposed even in a region (space) where no electrode is formed. The solder powder disposed in the region where no electrode is formed does not contribute to conduction between the electrodes.

Further, in Patent Literature 3, a convection additive is added in an electrically conductive paste containing solder powder. However, when a convection additive as described in Patent Document 3 is added, the convection additive may remain as a foreign material in the cured product of the conductive paste. In addition, the properties of the conductive paste may be changed by the addition of the convection additive. Also, voids tend to occur in the cured product of the conductive paste. As a result, the conduction reliability between the electrodes may be lowered. Also, the conductive paste that can be used is limited.

An object of the present invention is to provide an electrically-conductive material capable of efficiently disposing solder in conductive particles on an electrode even when the width of the electrode is narrow, and improving conduction reliability. Moreover, the object of this invention is to provide the connection structure using the said electrically conductive material.

According to a broad aspect of the present invention, a conductive material containing a plurality of conductive particles having solder, a thermosetting compound, a thiol curing agent, and an amine curing agent is provided on the outer surface portion of the conductive portion.

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

In a certain situation of the electrically-conductive material concerning this invention, a carboxyl group exists in the outer surface of the said electroconductive particle.

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

In a specific aspect of the conductive material according to the present invention, the weight ratio of the thiol curing agent to the amine curing agent is 2:1 to 50:1.

In a certain situation of the electrically-conductive material concerning this invention, the said electrically-conductive material contains insulating particle which is not adhering to the surface of the said electrically-conductive particle.

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

In a certain situation of the electrically-conductive material concerning this invention, content of the said electroconductive particle in 100weight% of the said electrically-conductive material is 10 weight% or more and 80 weight% or less.

In a specific aspect of the conductive material according to the present invention, the conductive material is liquefied at 25°C and is a conductive paste.

According to a broad aspect of the present invention, a first connection object member having a first electrode on its surface, a second connection object member having a second electrode on its surface, and the first connection object member and the second connection object member. A connection structure is provided which has a connection part being connected, the material of the connection part is the above-mentioned conductive material, and the first electrode and the second electrode are electrically connected by solder in the conductive particles.

Since the conductive material according to the present invention contains a plurality of conductive particles having solder on the outer surface portion of the conductive portion, a thermosetting compound, a thiol curing agent, and an amine curing agent, even if the width of the electrode is narrow, solder in the conductive particles can be efficiently placed on the electrode, and conduction reliability can be increased.

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

The details of the present invention will be described below.

(Challenge material)

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

The conductive material according to the present invention contains a thermosetting compound and a thermosetting agent as the binder. In the conductive material according to the present invention, as the thermal curing agent, a thiol curing agent and an amine curing agent are included.

In this invention, in order to use specific electroconductive particle and harden a thermosetting compound, two types of specific thermosetting agents are used together.

In this invention, since the said structure is provided, even if an electrode width is narrow, the solder in electroconductive particle can be arrange|positioned efficiently on an electrode. When the width of the electrode is narrow, it tends to be difficult to collect the solder of conductive particles on the electrode, but in the present invention, even when the width of the electrode is narrow, the solder can be sufficiently collected on the electrode. In the present invention, since the above structure is provided, when the electrodes are electrically connected, the solder in the conductive particles tends to gather between the upper and lower facing electrodes, and the solder in the conductive particles is formed on the electrode (line) can be placed efficiently. Further, in the present invention, when the width of the electrode is wide, the solder in the conductive particles is more efficiently disposed on the electrode.

In addition, part of the solder in the conductive particles is difficult to be disposed in the region (space) where no electrode is formed, and the amount of solder disposed in the region where the electrode is not formed can be significantly reduced. In the present invention, solder that is not located between the opposing electrodes can be efficiently moved between the opposing electrodes. Accordingly, reliability of conduction between the electrodes can be increased. In addition, it is possible to prevent electrical connection between electrodes adjacent to each other in the transverse direction, which should not be connected, so that insulation reliability can be improved.

Moreover, in this invention, the heat resistance of the hardened|cured material of a conductive material can be improved. In particular, when a conductive material is used for an optical semiconductor device, heat is generated during light irradiation, and the cured material of the conductive material is exposed to high temperatures. Since the electrically-conductive material concerning this invention is excellent in heat resistance of hardened|cured material, it can be used suitably 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 increases.

Further, in recent years, with the downsizing of electronic components and the like, cured products of conductive materials are required to be able to cope with high-speed transmission. In the present invention, the dielectric constant of the cured product of the conductive material can be lowered. Due to this, it is possible to respond to high-speed transmission. Since the conductive material according to the present invention can lower the dielectric constant of a cured product, it is suitably used for high-speed transmission applications.

Further, in the present invention, positional displacement between the electrodes can be prevented. In the present invention, when the second connection object member is superimposed on the first connection object member having the conductive material disposed thereon, in a state where the alignment of the electrode of the first connection object member and the electrode of the second connection object member are misaligned, Even when the first connection object member overlaps with the second connection object member, the misalignment can be corrected and the electrode of the first connection object member and the electrode of the second connection object member can be connected (self-alignment effect).

In order to more efficiently place the solder on the electrode, the conductive material is preferably in a liquid state at 25°C, and is preferably a conductive paste. In order to more efficiently place the solder on the electrode, the viscosity at 25°C (η25) of the conductive material is preferably 10 Pa·s or more, more preferably 50 Pa·s or more, still more preferably 100 Pa·s or more, preferably 800 Pa·s or less, more preferably 600 Pa·s or less, still more preferably 500 Pa·s or less. The said viscosity (η25) can be suitably adjusted according to the kind and compounding quantity of a compounding component.

The said viscosity (η25) can be measured on condition of 25 degreeC and 5 rpm using E-type viscometer ("TVE22L" by Toki Sangyo Co., Ltd.) etc., for example.

The conductive material may be used as a conductive paste and a conductive film. The conductive film is preferably an anisotropic conductive film. From the viewpoint of disposing the solder more efficiently on the electrode, it is preferable that the conductive material is a conductive paste. The conductive material is suitably used for electrical connection of electrodes. It is preferable that the said conductive material is a circuit connection material.

Hereinafter, each component included in the conductive material will be described. In addition, in this specification, "(meth)acrylate" means one or both of "acrylate" and "methacrylate", and "(meth)acryloxy" means "acryloxy" and "methacryloxy" ”, and “(meth)acryl” means either or both of “acryl” and “methacryl”.

(conductive particles)

The said electroconductive particle electrically connects between the electrodes of a connection object member. The said electroconductive particle has solder on the outer surface part of an electroconductive part. The conductive particles may be solder particles formed by solder. The solder particle has solder on the outer surface portion of the conductive portion. In the solder particle, both the central portion and the outer surface portion of the conductive portion are solder, and are formed by solder. The said solder particle does not have a substrate particle as a core particle. The said solder particle is different from substrate particle and electroconductive particle provided with the electrically conductive part arrange|positioned on the surface of the said substrate particle. The solder particles contain, for example, solder at preferably 80% by weight or more, more preferably 90% by weight or more, still more preferably 95% by weight or more. The said electroconductive particle may have substrate particle and the electroconductive part arrange|positioned on the surface of this substrate particle. In this case, the said electroconductive particle has solder on the outer surface part of a conductive part.

In addition, compared to the case where the above solder particles are used, when conductive particles having substrate particles not formed by solder and solder portions disposed on the surface of the substrate particles are used, it is difficult for the conductive particles to gather on the electrode, Since the solder bondability between the conductive particles is low, the conductive particles that have migrated onto the electrodes tend to move to the outside of the electrodes, and the effect of suppressing misalignment between the electrodes also tends to be low. Therefore, it is preferable that the said electroconductive particle is a solder particle formed by solder.

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

Hydroxyl groups exist on the surface of the solder. By covalently bonding this hydroxyl group with a group containing a carboxyl group, a stronger bond can be formed than in the case of bonding with other coordination bonds (chelate coordination), etc., so it is necessary to lower the connection resistance between electrodes and suppress the occurrence of voids. Possible conductive particles are obtained.

In the above conductive particles, the form of bonding between the surface of the solder and the group containing a carboxyl group does not need to include a coordination bond or a bond by chelate coordination.

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

A hydroxyl group, a carboxyl group, an ester group, a carbonyl group, etc. are mentioned as a functional group reactable with the said hydroxyl group. A hydroxyl group or a carboxyl group is preferred. The functional group capable of reacting with the hydroxyl group may be either 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, and 4-aminobutyric acid. , 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecane acids, hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, nonadecanoic acid, arachidic acid, decanoic acid and dodecanoic acid etc. can be mentioned. Glutaric acid or glycolic acid is preferred. As for the compound which has the functional group reactable with the said hydroxyl group, only 1 type may be used, and 2 or more types may be used together. It is preferable that the compound having a functional group capable of reacting with the hydroxyl group is 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 bonded to the surface of the solder. The compound having a flux action can remove the oxide film on the surface of the solder and the surface of the electrode. Carboxyl groups have a flux action.

As the compound having a flux action, levulinic acid, glutaric acid, glycolic 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 or glycolic acid is preferred. As for the compound which has the said flux action, only 1 type may be used, and 2 or more types may be used together.

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

The manufacturing method of the said electroconductive particle is equipped with the process of mixing the said electroconductive particle, the compound which has a functional group reactable with a hydroxyl group, and a carboxyl group, a catalyst, and a solvent, using electroconductive particle, for example. In the method for producing conductive particles, the conductive particles having a carboxyl group-containing group covalently bonded to the surface of the solder can be easily obtained through the mixing step.

In addition, in the manufacturing method of the said electroconductive particle, it is preferable to mix the said electroconductive particle, the compound which has the said hydroxyl group reactable functional group and the carboxyl group, the said catalyst, and the said solvent using electroconductive particle, and heat. Through the mixing and heating steps, it is possible to more easily obtain conductive particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder.

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

Examples of the catalyst include p-toluenesulfonic acid, benzenesulfonic acid, and 10-camphorsulfonic acid. The catalyst is preferably p-toluenesulfonic acid. 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 said mixing. The heating temperature is preferably 90°C or higher, more preferably 100°C or higher, and preferably 130°C or lower, more preferably 110°C or lower.

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

Moreover, a silane coupling agent can be easily made to react with the 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 a carboxyl group is added to a group derived from a silane coupling agent after a reaction using a silane coupling agent. What is introduced by reacting the compound which has at least 1 is preferable. The conductive particles are preferably obtained by reacting a hydroxyl group on the surface of the solder with a compound having at least one carboxyl group after using the isocyanate compound to react the isocyanate compound.

It is preferable that the compound which has at least one carboxyl group has two or more carboxyl groups from a viewpoint of effectively lowering the connection resistance in a bonded structure and suppressing generation|occurrence|production of a void effectively.

Examples of the isocyanate compound include diphenylmethane-4,4'-diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI). You may use isocyanate compounds other than these. After reacting this compound on the surface of the solder, a carboxyl group is introduced to the surface of the solder via a group represented by formula (X) by reacting a residual isocyanate group with a compound having a carboxyl group and having reactivity with the residual isocyanate group. can

As said isocyanate compound, you may use the compound which has an unsaturated double bond and also has an isocyanate group. Examples include 2-acryloyloxyethyl isocyanate and 2-isocyanatoethyl methacrylate. After the isocyanate group of this compound is reacted on the surface of the solder, a compound having a reactive functional group with respect to the remaining unsaturated double bond and a carboxyl group is reacted, through the group represented by the formula (X) on the surface of the solder , can introduce a carboxyl group.

As the silane coupling agent, 3-isocyanatopropyltriethoxysilane ("KBE-9007" manufactured by Shin-Etsu Silicone Co., Ltd.) and 3-isocyanatopropyltrimethoxysilane ("Y-5187" manufactured by MOMENTIVE Corporation) etc. can be mentioned. 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, and 4-aminobutyric acid. , 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecane acids, hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, nonadecanoic acid, arachidic acid, decanoic acid and dodecanoic acid etc. can be mentioned. Preference is given to glutaric acid, adipic acid or glycolic acid. As for the compound which has at least one said carboxyl group, only 1 type may be used and 2 or more types may be used together.

After the isocyanate compound is reacted with hydroxyl groups on the surface of the solder using the isocyanate compound, the carboxyl groups of some of the compounds having a plurality of carboxyl groups are reacted with the hydroxyl groups on the surface of the solder, so that groups containing carboxyl groups can remain. there is.

In the method for producing conductive particles, after using conductive particles and using an isocyanate compound to react the isocyanate compound with a hydroxyl group on the surface of the solder, a compound having at least one carboxyl group is reacted to form the surface of the solder The electroconductive particle with which the group containing a carboxyl group is couple|bonded via the group represented by the said formula (X) is obtained. In the above method for producing conductive particles, it is possible to easily obtain conductive particles having a group containing a carboxyl group introduced into the surface of the solder by the above steps.

As a specific manufacturing method of the said electroconductive particle, the following method is mentioned. Conductive particles are dispersed in an organic solvent, and a silane coupling agent having an isocyanate group is added. After that, a silane coupling agent is covalently bonded to the surface of the solder using a reaction catalyst between the hydroxyl group and isocyanate group on the surface of the solder of the conductive particles. Subsequently, a hydroxyl group is produced by hydrolyzing the alkoxy group bonded to the silicon atom of the silane coupling agent. The carboxyl group of the compound which has at least one carboxyl group is made to react with the produced|generated hydroxyl group.

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

Examples of the reaction catalyst between the hydroxyl group and isocyanate group on the solder surface of the conductive particles include tin-based catalysts (dibutyltin dilaurate, etc.), amine-based catalysts (triethylenediamine, etc.), carboxylate catalysts (lead naphthenate, potassium acetate, etc.) ) and trialkylphosphine catalysts (such as triethylphosphine).

It is preferable that the compound which has at least one carboxyl group is a compound represented by following formula (1) from a viewpoint of effectively lowering connection resistance in a bonded structure and suppressing generation|occurrence|production of a void effectively. The compound represented by the following formula (1) has a flux action. In addition, the compound represented by the following formula (1) has a flux action in a state introduced to the surface of the solder.

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

It is preferable that the compound which has the said carboxyl group at least 1 is a compound represented by following formula (1A) or following formula (1B). It is preferable that it is a compound represented by the following formula (1A), and, as for the said compound which has at least one carboxyl group, it is more preferable that it is a compound represented by the following formula (1B).

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

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

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

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

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

From the viewpoint of improving the surface wettability of the solder, the compound having at least one carboxyl group has a molecular weight of preferably 10000 or less, more preferably 1000 or less, still more preferably 500 or less.

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 identified. In addition, when the compound which has at least 1 said carboxyl group is a polymer, it means a weight average molecular weight.

It is preferable that the said electroconductive particle has an electroconductive particle main body and the anionic polymer arrange|positioned on the surface of the said electroconductive particle main body from the point which can effectively raise the cohesiveness of electroconductive particle at the time of conductive connection. It is preferable that the said electroconductive particle is obtained by surface-treating the electroconductive particle main body with an anionic polymer or a compound used as an anionic polymer. It is preferable that the said electroconductive particle is a surface-treated material by the compound used as an anionic polymer or an anionic polymer. As for the said anionic polymer and the compound used as the said anionic polymer, only 1 type may be used respectively, and 2 or more types may be used together. The anionic polymer is a polymer having an acidic group.

As a method of surface treatment of the conductive particle body with an anionic polymer, as the anionic polymer, for example, a (meth)acrylic polymer copolymerized with (meth)acrylic acid, a polyester synthesized from dicarboxylic acid and diol and having carboxyl groups at both ends Polymer, a polymer obtained by intermolecular dehydration condensation of dicarboxylic acid and having carboxyl groups at both ends, a polyester polymer synthesized from dicarboxylic acid and diamine and having carboxyl groups at both ends, and modified polyvinyl alcohol having carboxyl groups ("Kosei Nex T" by Nippon Kosei Chemical Co., Ltd.) etc., The method of making the carboxyl group of an anionic polymer and the hydroxyl group of the surface of the electroconductive particle main body react is mentioned.

Examples of the anionic portion of the anionic polymer include the carboxyl group, and other than that, a tosyl group (pH ₃ CC ₆ H ₄ S(=O) ₂ -), a sulfonate ion group (-SO ₃ -), and a phosphate ion group ( -PO ₄ -) etc. are mentioned.

In addition, as another method of surface treatment, a compound having a functional group that reacts with a hydroxyl group on the surface of the conductive particle body and a functional group capable of being polymerized by an addition or condensation reaction is used, and this compound is polymerized on the surface of the conductive particle body. You can find a way to get angry. A carboxyl group, an isocyanate group, etc. are mentioned as a functional group which reacts with the hydroxyl group of the surface of the electroconductive particle body, A hydroxyl group, a carboxyl group, an amino group, and a (meth)acryloyl group are mentioned as a functional group which superposes|polymerizes by addition and condensation reaction. .

The weight average molecular weight of the anionic polymer is preferably 2000 or more, more preferably 3000 or more, and preferably 10000 or less, more preferably 8000 or less. When the weight average molecular weight is more than the above lower limit and less than or equal to the above upper limit, a sufficient amount of charge and flux properties can be introduced into the surface of the conductive particles. In this way, the cohesiveness of the conductive particles can be effectively increased at the time of conductive connection, and the oxide film on the surface of the electrode can be effectively removed at the time of connection of the member to be connected.

When the weight average molecular weight is equal to or greater than the lower limit and equal to or less than the upper limit, it is easy to dispose the anionic polymer on the surface of the conductive particle body, and the cohesiveness of the solder particles can be effectively increased during conductive connection, thereby forming the conductive particles on the electrode. can be placed more efficiently.

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

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

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 It is preferably less than 6mgKOH.

The said acid value can be measured as follows. 1 g of conductive particles are added to 36 g of acetone and dispersed by ultrasonic waves for 1 minute. Then, it titrates with a 0.1 mol/L potassium hydroxide ethanol solution using phenolphthalein as an indicator.

Next, the specific example of electroconductive particle is demonstrated, referring drawings.

4 is a cross-sectional view showing a first example of conductive particles usable for 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 substrate particles in the core and are not core-shell particles. In the conductive particles 21, both the central portion and the outer surface portion of the conductive portion are formed by soldering.

5 is a cross-sectional view showing a second example of conductive particles usable for the conductive material.

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

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

6 is a cross-sectional view showing a third example of conductive particles usable for the conductive material.

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

Examples of the substrate particles include inorganic particles other than resin particles and metal particles, organic-inorganic hybrid particles, and metal particles. It is preferable that the said substrate particle is substrate particle excluding metal, and it is preferable that it is inorganic particle or organic-inorganic hybrid particle|grains excluding resin particle and metal particle. Copper particles may be sufficient as the said substrate particle.

As the resin for forming the resin particles, various organic materials are suitably used. 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 ketone, polyether sulfone, divinylbenzene polymer and divinylbenzene copolymer, etc. can be heard As said divinylbenzene type copolymer etc., a divinylbenzene-styrene copolymer, a divinylbenzene-(meth)acrylic acid ester copolymer, etc. are mentioned. Since the hardness of the resin particles can be easily controlled within a suitable range, the resin for forming the resin particles is preferably a polymer obtained by polymerizing one or two or more polymerizable monomers having an ethylenically unsaturated group.

When obtaining the resin particle by polymerizing a polymerizable monomer having an ethylenically unsaturated group, examples of the polymerizable monomer having an ethylenically unsaturated group include a non-crosslinkable monomer and a crosslinkable monomer.

As said non-crosslinkable monomer, For example, Styrenic monomers, such as styrene and (alpha)-methylstyrene; Carboxyl group-containing monomers, such as (meth)acrylic acid, maleic acid, and maleic anhydride; Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth) Alkyl (meth)acrylate compounds, such as an acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; oxygen atom-containing (meth)acrylate compounds such as 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate; nitrile-containing monomers such as (meth)acrylonitrile; Vinyl ether compounds, such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; acid vinyl ester compounds such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; and halogen-containing monomers such as trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene.

Examples of the crosslinkable monomer include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. Relate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate polyfunctional (meth)acrylate compounds such as poly(poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; Triallyl(iso)cyanurate, triallyltrimellitate, divinylbenzene, diallylphthalate, diallylacrylamide, diallylether, γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene and silane-containing monomers such as vinyltrimethoxysilane.

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

In the case where the substrate particles are inorganic particles other than metal or organic-inorganic hybrid particles, examples of inorganic substances for forming the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. The particles formed of the silica are not particularly limited, and examples thereof include particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, followed by firing as necessary. can Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

When the said substrate particle is a metal particle, silver, copper, nickel, silicon, gold, titanium, etc. are mentioned as a metal for forming this metal particle. When the said substrate particle is a metal particle, it is preferable that this metal particle is a copper particle. However, it is preferable that the said substrate particle is not a metal particle.

The method of forming an electroconductive part on the surface of the said substrate particle, and the method of forming a solder part on the surface of the said substrate particle, or on the surface of the said 2nd electroconductive part are not specifically limited. As a method of forming the conductive portion and the solder portion, for example, a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, by physical vapor deposition or physical adsorption method, and a method of coating the surface of the substrate particle with a paste containing metal powder or metal powder and a binder, and the like. Among them, methods by electroless plating, electroplating or physical impact are suitable. Methods such as vacuum deposition, ion plating, and ion sputtering are exemplified as methods by the physical vapor deposition. In addition, in the method by the said physical collision, theta composer (made by Tokuju Kosakusho Co., Ltd.) etc. are used, for example.

It is preferable that the melting|fusing point of the said substrate particle is higher than the melting|fusing point of the said soldering part. The melting point of the substrate particles preferably exceeds 160°C, more preferably exceeds 300°C, still more preferably exceeds 400°C, and particularly preferably exceeds 450°C. Moreover, the melting|fusing point of the said substrate particle may be less than 400 degreeC. 160 degreeC or less may be sufficient as the melting|fusing point of the said substrate particle. It is preferable that the softening point of the said substrate particle is 260 degreeC or more. The softening point of the said substrate particle may be less than 260 degreeC.

The said electroconductive particle may have a solder part of a single layer. The said electroconductive particle may have a several layered conductive part (solder part, 2nd conductive part). That is, in the said electroconductive particle, you may laminate|stack two or more layers of electroconductive parts.

The solder is preferably a metal having a melting point of 450°C or lower (low melting point metal). The solder portion is preferably a metal layer (low melting point metal layer) having a melting point of 450°C or less. The low melting point metal layer is a layer containing a low melting point metal. It is preferable that the solder in the said electroconductive particle is a metal particle (low melting point metal particle) whose melting|fusing point is 450 degreeC or less. The low melting point metal particles are particles containing a low melting point metal. The said low-melting-point metal shows the metal whose melting|fusing point is 450 degreeC or less. The melting point of the low melting point metal is preferably 300°C or lower, more preferably 160°C or lower. Moreover, it is preferable that the solder in the said electroconductive particle contains tin. The content of tin in 100% by weight of the metal contained in the solder portion and in 100% by weight of the metal contained in the solder in the conductive particles is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably It is preferably 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 equal to or more than the lower limit, the reliability of conduction between the conductive particles and the electrode further increases.

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

By using conductive particles having the solder on the outer surface of the conductive portion, the solder is melted and bonded to the electrode, and the solder conducts between the electrodes. For example, since the solder and the electrode tend to make surface contact rather than point contact, the connection resistance is lowered. In addition, as a result of using conductive particles having solder on the outer surface of the conductive portion, the bonding strength between the solder and the electrode is increased, separation between the solder and the electrode is more difficult to occur, and the conduction reliability is effectively improved.

The low melting point metal constituting the solder portion and the solder particle is not particularly limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, and tin-indium alloy. Among them, it is preferable that the low melting point metal is tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy in terms of excellent wettability to the electrode. It is more preferable that they are a tin-bismuth alloy and a tin-indium alloy.

The material constituting the solder (solder portion) is preferably a filler metal having a liquidus line of 450°C or less based on JIS Z3001: welding terminology. As a composition of the said solder, the metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium, etc. is mentioned, for example. Among them, a tin-indium system (117°C process) or a tin-bismuth system (139°C process), which has a low melting point and is lead-free, is preferable. That is, the solder preferably does not contain lead, and is preferably a solder containing tin and indium or a solder containing tin and bismuth.

In order to further increase the bonding strength between the solder and the electrode, the solder in the conductive particles is nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese , metals such as chromium, molybdenum, and palladium may be included. Further, from the viewpoint of further increasing the bonding strength between the solder and the electrode, the solder in the conductive particles preferably contains nickel, copper, antimony, aluminum or zinc. From the viewpoint of further increasing the bonding strength between the solder and the electrode in the solder portion or the conductive particles, the content of these metals for increasing the bonding strength is preferably 0.0001% by weight or more in 100% by weight of the solder in the conductive particles. , preferably 1% by weight or less.

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

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

Preferably, the second conductive part includes metal. The metal constituting the second conductive part is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. . Moreover, you may use tin-doped indium oxide (ITO) as said metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer or a gold layer, and still more preferably a copper layer. It is preferable that electroconductive particle has a nickel layer, a palladium layer, a copper layer, or a gold layer, it is more preferable to have a nickel layer or a gold layer, and it is still more preferable to have a copper layer. The connection resistance between electrodes becomes further low by using the electroconductive particle which has these preferable electroconductive parts for the connection between electrodes. In addition, a solder portion can be formed more easily on the surface of these preferable conductive portions.

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

The thickness of the conductive portion (thickness of the entire conductive portion) is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, still more preferably 0.5 μm. or less, particularly preferably 0.3 µm or less. The thickness of the conductive portion is the thickness of the entire conductive layer when the conductive portion is multilayered. When the thickness of the conductive portion is equal to or greater than the lower limit and equal to or less than the upper limit, sufficient conductivity is obtained, and the conductive particles are sufficiently deformed at the time of connection between the electrodes without becoming too hard.

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, and preferably 0.5 μm or less, more preferably It is 0.1 μm or less. When the thickness of the outermost conductive layer is equal to or greater than the lower limit and equal to or less than the upper limit, the coating with the outermost conductive layer becomes uniform, the corrosion resistance is sufficiently high, and the connection resistance between the electrodes is further reduced.

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

The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 3 μm or more, preferably 100 μm or less, more preferably 50 μm or less, still more preferably It is preferably 30 μm or less. When the average particle diameter of the conductive particles is equal to or greater than the lower limit and equal to or less than the upper limit, the solder of the conductive particles can be more efficiently disposed on the electrodes, and a large amount of solder of the conductive particles is disposed between the electrodes. It is easy, and the conduction reliability is further increased.

The "average particle diameter" of the said electroconductive particle shows a number average particle diameter. The average particle diameter of the conductive particles is obtained by, for example, observing 50 random conductive particles with an electron microscope or an optical microscope, calculating an average value, or performing laser diffraction type particle size distribution measurement.

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

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, even more preferably 10% by weight or more, particularly preferably 20% by weight or more, particularly preferably It is preferably 30% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, still more preferably 50% by weight or less. When the content of the conductive particles is equal to or greater than the lower limit and equal to or less than the upper limit, the solder in the conductive particles can be more efficiently disposed on the electrodes, and it is easy to dispose a large amount of solder in the conductive particles between the electrodes. , the conduction reliability is further increased. From the viewpoint of further enhancing conduction reliability, it is preferable that the content of the conductive particles is larger.

(thermosetting compound)

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

From the viewpoints of effectively increasing the heat resistance of the cured product and effectively lowering the dielectric constant of the cured product, the thermosetting compound preferably contains a thermosetting compound having a triazine skeleton. Examples of the thermosetting compound having a triazine skeleton include triazine triglycidyl ether, and the TEPIC series manufactured by Nissan Chemical Industries (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, TEPIC-UC) and the like.

As said epoxy compound, an aromatic epoxy compound is mentioned. Crystalline epoxy compounds, such as a resorcinol type epoxy compound, a naphthalene type epoxy compound, a biphenyl type epoxy compound, and a benzophenone type epoxy compound, are preferable. An epoxy compound that is solid at room temperature (23°C) and has a melting temperature below the melting point of solder is preferred. The melting temperature is preferably 100°C or lower, more preferably 80°C or lower, and preferably 40°C or higher. In the step of bonding the connection object members by using the above-described preferred epoxy compound, the viscosity is high, and positional displacement between the first connection object member and the second connection object member can be suppressed when acceleration is imparted by an impact such as conveyance. In addition, the viscosity of the conductive material can be greatly reduced by heat during curing, and the aggregation of the solder can be efficiently promoted.

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

(heat curing agent)

The thermal curing agent thermally cures the thermal curable compound. Examples of the thermal curing agent include an imidazole curing agent, a phenol curing agent, a thiol curing agent, an amine curing agent, an acid anhydride curing agent, a thermal cation initiator (thermal cation curing agent), and a thermal radical generating agent. In the present invention, a thiol curing agent and an amine curing agent are used. From the viewpoint of efficiently disposing the solder in the conductive particles on the electrode and from the viewpoint of enhancing the heat resistance of the cured product, when using conductive particles having solder on the outer surface portion of the conductive portion, a thiol curing agent and an amine curing agent are used in combination It has great meaning. As for the said thiol curing agent and amine curing agent, only 1 type may be used respectively, and 2 or more types may be used together.

The amine curing agent has an amino group. The amine curing agent is not particularly limited, and hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5.5]undecane, bis (4-aminocyclohexyl)methane, metaphenylenediamine, diaminodiphenylsulfone, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylene Diamine, diethylaminopropylamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, norborhendiamine, 1,2-diaminocyclohexane, laromine, diaminodiphenylmethane, benzylamine, adip acid dihydrazide, sebacic acid dihydrazide, dodecanediohydrazide, isophthalic acid dihydrazide, salicylic acid hydrazide, polyoxypropylene diamine and polyoxypropylene triamine; and the like.

It is preferable that the amine curing agent is an amine curing agent with low reactivity at 25 ° C. Specifically, since the curing degree of the conductive material becomes 80% or more, it is preferable to use an amine curing agent that requires 24 hours or more at 25°C, and since the curing degree of the conductive material becomes 80% or more, it requires 48 hours or more at 25°C. It is more preferable that it is an amine curing agent that does.

The degree of curing of the conductive material can be measured as follows.

Samples of the conductive material before and after curing are prepared. A 10 mg sample is taken, and the sample before and after curing is measured using a differential scanning calorimeter (DSC) in a nitrogen atmosphere under conditions where the temperature is raised from 25°C to 250°C at a rate of 5°C/min. From the obtained measurement results, the curing degree can be determined according to the exothermic peak ratio. As said differential scanning calorimeter (DSC), "DSC7020" by Hitachi High-Tech Science Co., Ltd. etc. are used, for example.

The thiol curing agent has a thiol group. The thiol curing agent is not particularly limited, but trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexakis-3-mercaptopropionate etc. can be mentioned.

It is preferable that the said thiol curing agent is a 1st-class thiol curing agent from a viewpoint of distributing the solder in electroconductive particle more efficiently on an electrode and further improving the conduction reliability between electrodes.

Further, from the viewpoint of further enhancing the reliability of conduction between electrodes, the thiol curing agent preferably has a plurality of thiol groups. It is preferable that the said thiol curing agent has a polyether frame|skeleton from a viewpoint of arrange|positioning the solder in electroconductive particle more efficiently on an electrode, and further improving the conduction reliability and insulation reliability between electrodes. It is preferable that the said thiol curing agent has 4 or more thiol groups from a viewpoint of arrange|positioning the solder in electroconductive particle on an electrode much more efficiently and further improving the conduction reliability between electrodes.

The reaction initiation temperature of the thermal curing 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 It is preferably 150°C or lower, particularly preferably 140°C or lower. The solder in electroconductive particle is arrange|positioned more efficiently on an electrode as the reaction start temperature of the said thermosetting agent is more than the said lower limit and below the said upper limit. The reaction initiation temperature of the thermal curing agent is particularly preferably 80°C or higher and 140°C or lower.

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

The reaction initiation temperature of the thermal curing agent means the temperature at which the exothermic peak begins to rise in DSC.

The total content of the thiol curing agent and the amine curing agent relative to 100 parts by weight of the thermosetting compound is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably Preferably it is 100 parts by weight or less, more preferably 75 parts by weight or less. It is easy to sufficiently harden an electrically-conductive material as content of a thermal curing agent is more than the said lower limit. If the content of the thermal curing agent is less than or equal to the above upper limit, it becomes difficult for the surplus thermal curing agent not involved in curing to remain after curing, and the heat resistance of the cured product further increases.

From the viewpoint of more efficiently disposing the solder in the conductive particles on the electrode and from the viewpoint of effectively increasing the heat resistance of the cured product, the weight ratio of the thiol curing agent and the amine curing agent in the conductive material is preferably 1:1 to 1:1. 100:1, more preferably 2:1 to 50:1, still more preferably 4:1 to 15:1.

(flux)

It is preferable that the said conductive material contains flux. The use of flux allows more effective placement of the solder on the electrodes. The flux is not particularly limited. As the flux, a flux generally used for solder bonding or the like can be used.

Examples of the flux include zinc chloride, a mixture of zinc chloride and inorganic halides, a mixture of zinc chloride and inorganic acids, molten salts, phosphoric acid, phosphoric acid derivatives, organic halides, hydrazine, organic acids and pine resin. As for the said flux, only 1 type may be used and 2 or more types may be used together.

Ammonium chloride etc. are mentioned as said molten salt. As said organic acid, lactic acid, citric acid, stearic acid, glutamic acid, glutaric acid, etc. are mentioned. As said paper, activation paper, inactivation paper, etc. are mentioned. It is preferable that the said flux is an organic acid or pine resin which has two or more carboxyl groups. The flux may be an organic acid having two or more carboxyl groups or a pine resin. Conduction reliability between the electrodes is further enhanced by the use of an organic acid having two or more carboxyl groups and pine resin.

The rosin is a type of rosin containing abietic acid as a main component. The flux is preferably rosin, more preferably abietic acid. The reliability of conduction between the electrodes is further enhanced by the use of this preferred flux.

The activation temperature (melting point) of the flux is preferably 50°C or higher, more preferably 70°C or higher, still more preferably 80°C or higher, and is preferably 200°C or lower, more preferably 190°C or lower, and more More preferably, it is 160°C or less, more preferably 150°C or less, still more preferably 140°C or less. When the activation temperature of the flux is equal to or higher than the lower limit and equal to or lower than the upper limit, the effect of the flux is exhibited more effectively, and the solder is more efficiently disposed on the electrode. The activation temperature (melting point) of the flux is preferably 80°C or more and 190°C or less. The activation temperature (melting point) of the flux is particularly preferably 80°C or more and 140°C or less.

Examples of the fluxes having an activation temperature (melting point) of 80°C or more and 190°C or less include succinic acid (melting point 186°C), glutaric acid (melting point 96°C), adipic acid (melting point 152°C), and pimelic acid (melting point 104°C). ), dicarboxylic acids such as suberic acid (melting point: 142°C), benzoic acid (melting point: 122°C), and malic acid (melting point: 130°C).

In addition, it is preferable that the boiling point of the flux is 200°C or less.

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

From the viewpoint of more efficiently disposing the solder in the conductive particles on the electrode, the melting point of the flux is preferably higher than the reaction initiation temperature of the thermal curing agent, more preferably 5 ° C. or higher, and 10 ° C. or higher Higher is more preferable.

The said flux may be disperse|distributed in an electrically-conductive material, or may adhere on the surface of electroconductive particle.

When the melting point of the flux is higher than that of the solder, the solder can be efficiently aggregated in the electrode portion. This is because when heat is applied at the time of bonding, when comparing the electrode formed on the connection object member and the portion of the connection object member around the electrode, the thermal conductivity of the electrode portion is higher than the thermal conductivity of the connection object member portion around the electrode. This is due to the fact that the temperature rise of the electrode portion is rapid. At a stage where the melting point of the solder is exceeded, the inside of the solder is melted, but the oxide film formed on the surface is not removed because the melting point (activation temperature) of the flux has not been reached. In this state, since the temperature of the electrode portion first reaches the melting point (activation temperature) of the flux, the oxide film on the surface of the solder on the electrode is preferentially removed, or the charge on the surface of the solder is neutralized by the activated flux. By doing so, the solder can be spread on the surface of the electrode. Thereby, it is possible to efficiently aggregate the solder on the electrode.

It is preferable that the said flux is a flux which releases positive ion by heating. The solder can be placed on the electrodes more efficiently by the use of a flux that releases positive ions upon heating.

Examples of the flux that releases cations by heating include the thermal cation initiator (thermal cation curing agent).

The content of the flux in 100% by weight of the conductive material is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less. The conductive material need not contain flux. When the content of the flux is equal to or greater than the lower limit and equal to or less than the upper limit, the formation of an oxide film on the surface of the solder and the electrode becomes more difficult, and the oxide film formed on the surface of the solder and the electrode can be more effectively removed.

(insulating particles)

From the viewpoint of controlling with high accuracy the distance between the connection target members connected by the cured material of the conductive material and the distance between the connection target members connected by the solder in the conductive particles, the conductive material contains insulating particles it is desirable In the above conductive material, the insulating particles do not have to adhere to the surface of the conductive particles. In the above conductive material, the insulating particles need not be in contact with the surface of the conductive particles. Among the conductive materials, it is preferable that the insulating particles exist apart from the conductive particles.

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

As a material of the said insulating particle|grain, insulating resin, an insulating inorganic substance, etc. are mentioned. As said insulating resin, the said resin illustrated as resin for forming the resin particle which can be used as substrate particle|grains is mentioned. As said insulating inorganic substance, the said inorganic substance illustrated as an inorganic substance for forming the inorganic particle which can be used as substrate particle|grains is mentioned.

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

As said polyolefin compound, polyethylene, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, etc. are mentioned. As said (meth)acrylate polymer, polymethyl (meth)acrylate, polyethyl (meth)acrylate, polybutyl (meth)acrylate, etc. are mentioned. Examples of the block polymers include polystyrene, styrene-acrylic acid ester copolymers, SB type styrene-butadiene block copolymers and SBS type styrene-butadiene block copolymers, and hydrogenated products thereof. As said thermoplastic resin, a vinyl polymer, a vinyl copolymer, etc. are mentioned. 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, polyvinylpyrrolidone, polyethylene oxide, and methyl cellulose. Especially, water-soluble resin is preferable and polyvinyl alcohol is more preferable.

The content of the insulating particles in 100% by weight of the conductive material is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and preferably 10% by weight or less, more preferably 5% by weight or less. The said electrically-conductive material does not need to contain insulating particle|grains. If the content of the insulating particles is more than the lower limit and less than or equal to the upper limit, the distance between the connection target members connected by the cured product of the conductive material and the connection target member connected by the solder in the conductive particles are further increased. become suitable

(other ingredients)

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

(Connection structure and manufacturing method of connection structure)

The connection structure according to the present invention comprises a first connection object member having at least one first electrode on its surface, a second connection object member having at least one second electrode on its surface, said first connection object member, The connection part which connects the said 2nd connection object member is provided. In the connection structure according to the present invention, the connection portion is formed of the above-mentioned conductive material. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by a solder portion in the connection portion.

The manufacturing method of the said connection structure includes the step of disposing the said conductive material on the surface of the 1st connection object member which has at least one 1st electrode on the surface using the above-mentioned conductive material, and the said conductive material a step of arranging a second connection object member having at least one second electrode on its surface on a surface opposite to the first connection object member side so that the first electrode and the second electrode face each other; By heating the conductive material to a temperature equal to or higher than the melting point of the solder in the particle, a connection portion connecting the first connection member and the second connection member is formed of the conductive material, and the first electrode and A step of electrically connecting the second electrode with a solder portion in the connecting portion is provided. Preferably, the conductive material is heated above the curing temperature of the thermosetting compound.

In the bonded structure and the method for manufacturing the bonded structure according to the present invention, since a specific conductive material is used, solder in a plurality of conductive particles tends to gather between the first electrode and the second electrode, and the solder is applied to the electrode (line) can be placed efficiently. In addition, it is difficult for a portion of the solder to be placed in the region (space) where no electrode is formed, and the amount of solder placed in the region where no electrode is formed can be significantly reduced. Accordingly, reliability of conduction between the first electrode and the second electrode can be increased. In addition, it is possible to prevent electrical connection between electrodes adjacent to each other in the transverse direction, which should not be connected, so that insulation reliability can be improved.

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

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

In the method for manufacturing a connected structure according to the present invention, in the step of arranging the second connection object member and the step of forming the connection portion, pressurization is not performed, and the conductive material has a weight of the second connection object member. It is preferable to apply, and in the step of arranging the second connection object member and the step of forming the connection portion, pressing pressure exceeding the force of the weight of the second connection object member is not applied to the conductive material it is desirable In these cases, the uniformity of the amount of solder can be further improved in a plurality of solder portions. In addition, the thickness of the solder portion can be further effectively increased, and a large amount of solder in the plurality of conductive particles tends to gather between the electrodes, so that the solder in the plurality of conductive particles can be more efficiently applied on the electrode (line). can be placed as 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 no electrode is formed, and the amount of solder in the region where the electrode is not formed is further reduced. can do less Accordingly, the conduction reliability between the electrodes can be further enhanced. In addition, electrical connection between electrodes adjacent to each other in the transverse direction, which should not be connected, can be further prevented, and insulation reliability can be further improved.

Further, in the step of arranging the second connection object member and the step of forming the connection portion, when the weight of the second connection object member is applied to the conductive material without applying pressure, the electrode is formed before the connection portion is formed. The solder disposed in this unformed region (space) is more likely to gather between the first electrode and the second electrode, and the solder in the plurality of conductive particles is more efficiently disposed on the electrode (line) can do. In the present invention, the present invention adopts a combination of 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 object member is applied to the conductive paste without applying pressure. It is of great significance because the effect of is obtained at a higher level.

In addition, in WO2008/023452A1, from the viewpoint of efficiently moving the solder powder by flowing it to the surface of the electrode, it is described that pressing with a predetermined pressure during bonding is necessary. From the point of view, it is described that, for example, 0 MPa or more, preferably 1 MPa or more, and even if the pressure intentionally applied to the adhesive tape is 0 MPa, the self-weight of the member disposed on the adhesive tape causes adhesion It is described that a predetermined pressure may be applied to the tape. In WO2008/023452A1, it is described that the pressure applied intentionally to the adhesive tape may be 0 MPa, but the difference in effect between the case where a pressure exceeding 0 MPa is applied and the case where it is set to 0 MPa is not described at all. In addition, in WO2008/023452A1, the importance of using a paste-form conductive paste rather than a film form is not recognized at all.

In addition, if a conductive paste is used instead of a conductive film, it becomes easy to adjust the thickness of the connection portion and the solder portion according to 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 connecting portion, there is a problem that a conductive film having a different thickness or a conductive film having a predetermined thickness must be prepared. Further, in the conductive film, compared to the conductive paste, the melt viscosity of the conductive film cannot be lowered sufficiently at the melting temperature of the solder, and the aggregation of the solder tends to be easily inhibited.

EMBODIMENT OF THE INVENTION Hereinafter, specific embodiment of this invention is described, referring drawings.

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 connects the 1st connection object member 2, the 2nd connection object member 3, the 1st connection object member 2, and the 2nd connection object member 3. It is provided with the connection part 4 which is doing. The connecting portion 4 is formed of the above-mentioned conductive material. The material of the connection part 4 is the above-mentioned conductive material. In this embodiment, the conductive material is conductive particles and contains solder particles.

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

The 1st connection object member 2 has the some 1st electrode 2a on the surface (upper surface). The 2nd connection object member 3 has the some 2nd electrode 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by a solder portion 4A. Therefore, the 1st connection object member 2 and the 2nd connection object member 3 are electrically connected by the solder part 4A. In addition, in the connection part 4, solder does not exist in the area|region (hardened|cured material part 4B part) different from the solder part 4A gathered between the 1st electrode 2a and the 2nd electrode 3a. In a region different from the solder portion 4A (a portion of the cured product portion 4B), there is no solder that is separated from the solder portion 4A. In addition, as long as it is a small amount, solder may exist in a region different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a (cured product portion 4B portion).

As shown in Fig. 1, in the bonded structure 1, a plurality of solder particles gather between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the solder particles After the molten material spreads over the surface of the electrode, it is solidified to form the solder portion 4A. This increases the connection area between the solder portion 4A and the first electrode 2a and between the solder portion 4A and the second electrode 3a. That is, by using solder particles, compared to the case where conductive particles of metal such as nickel, gold, or copper are used for the outer surface portion of the conductive portion, the solder portion 4A, the first electrode 2a, and the solder portion 4A ) and the second electrode 3a increase in contact area. For this reason, the conduction reliability and connection reliability in the connection structure 1 increase. Also, the conductive material may contain flux. When flux is used, the flux is generally gradually deactivated by heating.

Moreover, in the connection structure 1 shown in FIG. 1, all 4 A of solder parts are located in the opposing area|region between 1st and 2nd electrodes 2a and 3a. The connection structure 1X of the modified example shown in FIG. 3 differs from the connection structure 1 shown in FIG. 1 only in connection part 4X. The connection portion 4X has a solder portion 4XA and a cured product portion 4XB. Like the connection structure 1X, most of the solder portion 4XA is located in the region where the first and second electrodes 2a and 3a face each other, and a part of the solder portion 4XA is located in the region where the first and second electrodes 2a and 3a face each other. You may protrude sideways from the area|region where electrodes 2a and 3a oppose. The solder portion 4XA protruding laterally from the opposing regions of the first and second electrodes 2a and 3a is a part of the solder portion 4XA, and is not a solder separated from the solder portion 4XA. . Further, in the present embodiment, although the amount of solder separated from the solder portion can be reduced, the solder separated from the solder portion may exist in the cured product portion.

Reducing the amount of solder particles used makes it easier to obtain the bonded structure 1 . If the amount of solder particles used is increased, it becomes easier to obtain the bonded structure 1X.

From the viewpoint of further enhancing the conduction reliability, in the bonded structures 1 and 1X, the first electrode 2a and the second electrode 2a are stacked in the stacking direction of the first electrode 2a, the connection portions 4 and 4X, and the second electrode 3a. 50% or more (more preferably 60% or more, more preferably 60% or more) of 100% of the area of the mutually opposing portions of the first electrode 2a and the second electrode 3a when viewing the mutually opposing portions of the two electrodes 3a. Preferably 70% or more, particularly preferably 80% or more, and particularly preferably 90% or more), it is preferable that the solder portions 4A, 4XA in the connecting portions 4, 4X are disposed.

From the viewpoint of further increasing the conduction reliability, when viewing portions of the first electrode and the second electrode that 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 are viewed. 50% or more (more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, particularly preferably 90% or more) out of 100% of the area of the portions facing each other of the two electrodes, It is preferable that the solder part in the said connection part is arrange|positioned.

From the viewpoint of further increasing conduction reliability, when viewing portions of the first electrode and the second electrode facing each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode face each other. 70% or more (more preferably 80% or more, still more preferably 90% or more, particularly preferably 95% or more, particularly preferably 95% or more, particularly preferably is 99% or more) is preferably disposed.

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

First, the 1st connection object member 2 which has the 1st electrode 2a on the surface (upper surface) is prepared. Next, as shown in Fig. 2 (a), on the surface of the first connection object member 2, the conductive material 11 containing the thermosetting component 11B and a plurality of solder particles 11A is arranged (1st process). The conductive material used contains a thermosetting compound, a thiol curing agent, and an amine curing agent as the thermally curable component 11B.

On the surface on which the 1st electrode 2a of the 1st connection object member 2 was formed, the electrically-conductive material 11 is arrange|positioned. After disposing of the conductive material 11, the solder particles 11A are disposed both on the first electrode 2a (line) and on the region (space) where the first electrode 2a is not formed.

Although it does not specifically limit as a method of disposing the conductive material 11, application|coating by a dispenser, screen printing, discharge by an inkjet apparatus, etc. are mentioned.

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. 2(b), in the conductive material 11 on the surface of the first connection object member 2, the first connection object member 2 side of the conductive material 11 and arrange|positions the 2nd connection object member 3 on the surface of the opposite side (2nd process). On the surface of the electrically-conductive material 11, the 2nd connection object member 3 is arrange|positioned from the 2nd electrode 3a side. At this time, the 1st electrode 2a and the 2nd electrode 3a are made to face.

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). During this heating, the solder particles 11A existing in the region where no electrode is formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). In the case of using a conductive paste instead of a conductive film, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. Further, the solder particles 11A are melted and bonded to each other. Also, the heat curable component 11B is heat cured. As a result, as shown in FIG. 2(c) , the connection portion 4 connecting the first connection object member 2 and the second connection object member 3 is formed by the conductive material 11. do. The connection portion 4 is formed of the conductive material 11, the solder portion 4A is formed by bonding a plurality of solder particles 11A, and the thermosetting component 11B is thermally cured, thereby forming the cured product portion 4B. is formed

In this embodiment, it is preferable not to pressurize in the said 2nd process and the said 3rd process. In this case, the weight of the second connection object member 3 is applied to the conductive material 11 . For this reason, at the time of formation of the connection part 4, the solder particle 11A collects effectively between the 1st electrode 2a and the 2nd electrode 3a. In addition, in at least one of the second process and the third process, when pressurization is performed, the tendency for solder particles to gather between the first electrode and the second electrode is inhibited.

However, as long as the space between the first electrode and the second electrode can be secured, pressurization may be performed. As a means for securing the interval between electrodes, for example, insulating particles (spacers) corresponding to the desired interval between electrodes may be added, and at least one, preferably three or more insulating particles may be disposed between the electrodes. .

In addition, in this embodiment, since the pressurization is not performed, when the second connection object member is overlapped on the first connection object member coated with the conductive material, the electrode of the first connection object member and the second connection object member are separated. Even when the first connection object member and the second connection object member overlap with each other in a state where the alignment of the electrodes is misaligned, the misalignment can be corrected and the electrode of the first connection object member and the electrode of the second connection object member can be connected. Yes (self-alignment effect). This is because the molten solder self-aggregated between the electrode of the first connection member and the electrode of the second connection member is the solder between the electrode of the first connection member and the electrode of the second connection member and the conductive material. This is because the direction in which the area in contact with the external components is minimized is energetically stable, and the force acting on the connection structure that is the alignment, which is the connection structure with the minimum area, acts. At this time, it is preferable that the conductive material is not cured, and that the viscosity of components other than the conductive particles of the conductive material is sufficiently low at that temperature and time.

In this way, the connection structure 1 shown in FIG. 1 is obtained. In addition, the said 2nd process and the said 3rd process may be performed continuously. Furthermore, after performing the said 2nd process, the obtained laminated body of the 1st connection object member 2, the electrically-conductive material 11, and the 2nd connection object member 3 is moved to a heating part, and the said 3rd process is performed, can also 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, still more preferably 200°C or lower.

Moreover, after the said 1st heating process or the said 2nd heating process, the 1st connection object member or the 2nd connection object member can be peeled from a connection part for the purpose of correcting a position or retrying manufacture. The heating temperature for performing this peeling is preferably equal to or higher than the melting point of the solder, more preferably equal to or higher than the melting point (° C.) of the solder plus 10°C. The heating temperature for performing this peeling may be equal to or lower than the melting point (° C.) of solder + 100° C.

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

A hot plate, a heat gun for applying hot air, a soldering iron, an infrared heater, etc. are mentioned as a mechanism used for the method of locally heating.

In addition, when locally heated on a hot plate, a metal with high thermal conductivity is used directly below the connection portion, and a material with low thermal conductivity such as fluororesin is used for other areas where it is undesirable to heat, forming the upper surface of the hot plate. it is desirable

The said 1st, 2nd connection object member is not specifically limited. Specifically, as the first and second connection target members, electronic components and resin films such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors and diodes, printed boards, flexible printed boards, flexible flat cables, rigid flexible Electronic parts, such as circuit boards, such as a board|substrate, a glass epoxy board|substrate, and a glass board|substrate, etc. are mentioned. It is preferable that the said 1st, 2nd connection object member is an electronic component.

It is preferable that at least one of the said 1st connection object member and the said 2nd connection object member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible board. It is preferable that the said 2nd connection object member is a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. Resin films, flexible printed boards, flexible flat cables, and rigid flexible boards have properties of high flexibility and relatively light weight. When a conductive film is used for the connection of such a connection object member, there is a tendency for solder to be difficult to gather on the electrode. In contrast, by using a conductive paste, even if a resin film, flexible printed circuit board, flexible flat cable or rigid flexible substrate is used, the reliability of conduction between the electrodes can be sufficiently increased by efficiently collecting solder on the electrodes. In the case of using a resin film, a flexible printed board, a flexible flat cable or a rigid flexible board, the effect of improving the conduction reliability between the electrodes by not applying pressure is higher than in the case of using other connection object members such as semiconductor chips. obtained more effectively.

Examples of the electrode formed on the member to be connected include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the member to be connected is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode or a copper electrode. When the said connection object member is a glass substrate, it is preferable that the said electrode is an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. In the case where the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Sn, Al, and Ga etc. are mentioned as said trivalent metal element.

Hereinafter, the present invention will be described in detail by way of Examples and Comparative Examples. The present invention is not limited only to the following examples.

Polymer A:

(1) Synthesis of a first reactant of bisphenol F and 1,6-hexanediol diglycidyl ether and a bisphenol F-type epoxy resin:

Bisphenol F (including 4,4'-methylenebisphenol, 2,4'-methylenebisphenol, and 2,2'-methylenebisphenol in a weight ratio of 2:3:1) 72 parts by weight, 1,6-hexanediol digly 270 parts by weight of cydyl ether and 30 parts by weight of a bisphenol F-type epoxy resin ("Epiclon EXA-830CRP" manufactured by DIC Corporation) were placed in a three-necked flask and dissolved at 100°C under a nitrogen flow. Thereafter, 0.1 part by weight of tetra-n-butylsulfonium bromide, which is an addition reaction catalyst between a hydroxyl group and an epoxy group, was added, and addition polymerization was carried out at 130° C. for 6 hours under a nitrogen flow to obtain a first reactant.

It was confirmed by NMR that the addition polymerization reaction had progressed, and the first reactant was a structural unit in which a hydroxyl group derived from bisphenol F, 1,6-hexanediol diglycidyl ether, and an epoxy group of a bisphenol F-type epoxy resin were bonded to each other in the main chain. , and it was confirmed that it had an epoxy group at both ends.

(2) Synthesis of Polymer A

100 parts by weight of the first reactant was put into a three-necked flask and dissolved at 120° C. under a nitrogen flow. Then, 2 parts by weight of "KBE-9007" (3-isocyanate propyltriethoxysilane) manufactured by Shin-Etsu Silicone Co., Ltd. was added, and a reaction catalyst between the side chain hydroxyl group of the first reactant and the isocyanate group of 3-isocyanate propyltriethoxysilane 0.002 parts by weight of dibutyltin phosphorus dilaurate was added and reacted at 120°C for 4 hours under a nitrogen flow. Thereafter, vacuum drying was performed at 110°C for 5 hours to remove unreacted KBE-9007.

By NMR, it was confirmed that the reaction between the side chain hydroxyl group of the first reactant and the isocyanate group of 3-isocyanatepropyltriethoxysilane had progressed, and the obtained compound was hydroxyl group derived from bisphenol F and 1,6-hexanediol digly. It was confirmed that the main chain had a structural unit in which cydyl ether and an epoxy group of a bisphenol F-type epoxy resin were bonded, and also had an epoxy group at both ends and a propyltriethoxysilane group at the side chain. This obtained a phenoxy resin (polymer A).

Heat curable compound 1: Resorcinol type epoxy compound, Kyoeisha Chemical Co., Ltd. "Epolite TDC-LC", epoxy equivalent 120 g/eq

Thermosetting compound 2: Epoxy compound, "EP-3300" manufactured by Adeka Co., Ltd., epoxy equivalent 160 g/eq

Thermosetting compound 3: Epoxy compound, "TEPIC-SS" manufactured by Nissan Chemical Industries, Ltd., epoxy equivalent 100 g/eq

Thermosetting compound 4: Epoxy compound, manufactured by Nissan Chemical Industries, Ltd. "TEPIC-VL", epoxy equivalent 135 g/eq

Thermal Curing Agent 1: Trimethylolpropanetris (3-mercaptopropionate), "TMMP" manufactured by SC Yuki Chemical Co., Ltd.

Thermal curing agent 2: pentaerythritol tetrakis-3-mercaptopropionate, "PEMP" manufactured by SC Yuki Chemical Co., Ltd.

Thermal curing agent 3: dipentaerythritol hexakis-3-mercaptopropionate, "DPMP" manufactured by SC Yuki Chemical Co., Ltd.

Latent epoxy heat curing agent 1: "Fuji Cure 7000" manufactured by T&K TOKA

Latent epoxy heat curing agent 2: "HXA-3922HP" manufactured by Asahi Kasei E-Materials

Latent epoxy heat curing agent 3: polyoxypropylene diamine, "Jeffamine D-230" manufactured by Huntsman Corporation

Latent epoxy heat curing agent 4: polyoxypropylenetriamine, "Jeffamine T-403" manufactured by Huntsman Corporation

Flux 1: glutaric acid, manufactured by Wako Pure Chemical Industries, Ltd., melting point 96°C

Insulating particles: average particle diameter of 30 μm, CV value of 5%, softening point of 330° C., Sekisui Chemical Co., Ltd., divinylbenzene crosslinked particles

Solder particle A (SnBi solder particle, melting point 139°C, "ST-5" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter 5 µm))

Solder particles 1 to 3:

Manufacturing method of solder particle 1:

SnBi solder particles (“ST-5” manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 5 μm) and glutaric acid (a compound having two carboxyl groups, “glutaric acid” manufactured by Wako Pure Chemical Industries, Ltd.) were used as a catalyst By using phosphorus p-toluenesulfonic acid and stirring for 8 hours while dehydrating at 90°C in a toluene solvent, solder particles 1 in which groups containing carboxyl groups are covalently bonded to the surface of the solder were obtained.

Regarding the molecular weight of the polymer formed on the solder surface, after dissolving the solder with 0.1 N hydrochloric acid, the polymer was recovered by filtration and the weight average molecular weight was determined by GPC.

In the obtained solder particle 1, the CV value was 20% and the molecular weight Mw of the polymer constituting the surface was 2000.

Manufacturing method of solder particle 2:

200 g of SnBi solder particles (“ST-5” manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 5 μm), 10 g of a silane coupling agent having an isocyanate group (“KBE-9007” manufactured by Shin-Etsu Chemical Industry Co., Ltd.), and 70 g of acetone was weighed into a three-necked flask. While stirring at room temperature, 0.25 g of dibutyltin laurate, which is a reaction catalyst between hydroxyl groups on the surface of solder particles and isocyanate groups, was added, and the mixture was heated at 100°C for 2 hours in a nitrogen atmosphere while stirring. Then, 50 g of methanol was added, and it heated at 60 degreeC for 1 hour in nitrogen atmosphere under stirring.

Thereafter, it was cooled to room temperature, the solder particles were filtered with a filter paper, and desolvation was performed at room temperature for 1 hour by vacuum drying.

The solder particles were placed in a three-necked flask, 70 g of acetone, 30 g of monoethyl adipate, and 0.5 g of monobutyltin oxide as a transesterification reaction catalyst were added, followed by reaction at 60°C for 1 hour under nitrogen atmosphere under stirring.

As a result, the ester group of monoethyl adipate was reacted with the silanol group derived from the silane coupling agent by a transesterification reaction to form a covalent bond.

Thereafter, 10 g of adipic acid was added and reacted at 60°C for 1 hour to add adipic acid to the remaining ethyl ester groups not reacting with the silanol group of monoethyl adipate.

Thereafter, cooling to room temperature, filtering the solder particles with a filter paper, washing the solder particles with hexane on the filter paper, and unreacted and non-covalently attached to the surface of the solder particles, residual monoethyl adipic acid, adip After removing the acid, desolvation was performed by vacuum drying at room temperature for 1 hour.

After the obtained solder particles were pulverized with a ball mill, a sieve was selected so as to have a predetermined CV value.

In this way, solder particles 2 were obtained. In the obtained solder particle 2, the CV value was 20% and the molecular weight Mw of the polymer constituting the surface was 9800.

Manufacturing method of solder particle 3:

In the step of obtaining the solder particles 2, solder particles 3 were obtained in the same manner except that monoethyl adipate was changed to monoethyl glutarate and adipic acid was changed to glutaric acid.

In the obtained solder particle 3, the CV value was 20%, and the molecular weight of the polymer constituting the surface was Mw = 9600.

(CV value of solder particles)

The CV value was measured with a laser diffraction type particle size distribution analyzer (“LA-920” manufactured by Horiba Seisakusho Co., Ltd.).

(Examples 1 to 14 and Comparative Examples 1 to 2)

(1) Preparation of anisotropic conductive paste

The components shown in Tables 1 and 2 below were blended in the compounding amounts shown in Tables 1 and 2 below to obtain an anisotropic conductive paste.

Bonded structures of the kind shown in Tables 1 and 2 below were produced as follows.

(2) Fabrication of connection structure (L/S = 40 μm/40 μm)

Glass epoxy substrate (FR-4 substrate, thickness 0.6 mm) having on the upper surface a copper electrode pattern (copper electrode thickness 12 μm) with an L/S of 40 μm/40 μm and an electrode length of 3 mm (first connection target member) prepared In addition, a flexible printed circuit board having a copper electrode pattern (copper electrode thickness of 12 μm) with an L / S of 40 μm / 40 μm and an electrode length of 3 mm (a second connection target member formed of polyimide, thickness 0.1 mm) was prepared.

The overlapping area of the glass epoxy substrate and the flexible printed circuit board was 1.5 cm x 3 mm, and the number of connected electrodes was 75 pairs.

On the upper surface of the glass epoxy substrate, an anisotropic conductive paste immediately after preparation was applied on the electrode of the glass epoxy substrate to a thickness of 100 μm to form an anisotropic conductive paste layer. Subsequently, the flexible printed circuit board was laminated on the upper surface of the anisotropic conductive paste layer so that the electrodes faced each other. At this time, pressurization was not performed. The weight of the flexible printed circuit board is applied to the anisotropic conductive paste layer.

Thereafter, the temperature of the anisotropic conductive paste layer was heated to 139° C. (melting point of solder) 5 seconds after the start of the heating. Further, after 15 seconds from the start of the temperature rise, the anisotropic conductive paste layer was heated to a temperature of 160° C., the anisotropic conductive paste was cured, and a bonded structure was obtained.

(evaluation)

(1) Viscosity

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

(2) Thickness of solder part

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

(3) Accuracy of placement of solder on electrodes 1

In the obtained bonded structure, when the portion of the first electrode and the second electrode facing each other is viewed in the stacking direction of the first electrode, the connecting portion, and the second electrode, the area of the portion of the first electrode and the second electrode facing each other is 100 The ratio X of the area where the solder part is arranged in the connection part in % was evaluated. The placement accuracy 1 of the solder on the electrode was determined according to the following criteria.

[Judgment Criteria for Solder Placement Accuracy 1 on Electrodes]

○○: Ratio X is 70% or more

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

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

×: ratio X is less than 50%

(4) Accuracy of placement of solder on the electrode 2

In the obtained bonded structure, when the portion of the first electrode and the second electrode facing each other is viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode among 100% of the solder portion in the connection portion The ratio Y of the solder portion in the connecting portion arranged in the portion facing each other of the electrode and the second electrode was evaluated. The placement accuracy 2 of the solder on the electrode was determined according to the following criteria.

[Judgment Criteria for Solder Placement Accuracy 2 on Electrodes]

○○: Ratio Y is 99% or more

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

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

×: Ratio Y is less than 70%

(5) Reliability of conduction between upper and lower electrodes

In the obtained bonded structure (n = 15 pieces), the connection resistance per connection point between the upper and lower electrodes was measured by the 4-terminal method, respectively. The average value of connection resistance was computed. Further, from the relationship of voltage = current × resistance, connection resistance can be obtained by measuring the voltage when a constant current is applied. Conductivity reliability was determined according to the following criteria.

[Judgment Criteria for Continuity Reliability]

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

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

△: The average value of the connection resistance exceeds 70 mΩ and is 100 mΩ or less

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

(6) Insulation reliability between horizontally adjacent electrodes

In the obtained bonded structure (n = 15 pieces), after being left for 100 hours in an atmosphere of 85°C and 85% humidity, 15 V was applied between electrodes adjacent to each other in the horizontal direction, and resistance values were measured at 25 locations. Insulation reliability was determined according to the following criteria.

[Criteria for Insulation Reliability]

○○○: 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

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

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

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

(7) Displacement between upper and lower electrodes

In the obtained bonded structure, when viewing portions of the first electrode and the second electrode facing each other in the stacking direction of the first electrode, the connecting portion, and the second electrode, whether the center line of the first electrode and the center line of the second electrode are aligned. , and the distance of positional deviation were evaluated. The displacement between the upper and lower electrodes was determined according to the following criteria.

[Criterion for determining the displacement between the upper and lower electrodes]

○○: Position deviation less than 15 μm

○: Position deviation of 15 μm or more and less than 25 μm

△: position deviation of 25 μm or more and less than 40 μm

×: Positional deviation of 40 µm or more

(8) heat resistance (heat yellowing resistance)

In the mixing components shown in Tables 1 and 2 below, formulations containing components other than solder particles in the conductive paste were prepared, and a cured sheet having a thickness of 0.6 mm was produced. After exposure at 150°C for 1000 hours, heat resistance (heat resistance to yellowing) was evaluated by measuring transmittance at a measurement wavelength of 400 nm. Heat resistance was determined according to the following criteria.

[Criterion for determining heat resistance]

○○: transmittance of 90% or more

○: transmittance of 80% or more and less than 90%

△: transmittance of 70% or more and less than 80%

×: transmittance less than 70%

The results are shown in Tables 1 and 2 below.

A similar tendency was observed even when a flexible printed circuit board was used and a resin film, a flexible flat cable, and a rigid flexible board were used.

1, 1X... connection structure
2… 1st connection target member
2a... first electrode
3... Second connection target member
3a... second electrode
4, 4X... connection
4A, 4XA... solder part
4B, 4XB... hardened material part
11... conductive paste
11A... Solder particles (conductive particles)
11B... thermosetting component
21... Conductive Particles (Solder Particles)
31... conductive particles
32... substrate particles
33... Conductive part (conductive part with solder)
33A... 2nd conducting part
33B... solder part
41... conductive particles
42... solder part

Claims (10)

A plurality of conductive particles having solder on the outer surface portion of the conductive portion;
a thermosetting compound;
a thiol curing agent;
an amine curing agent;
The conductive material, wherein the weight ratio of the thiol curing agent to the amine curing agent is 4:1 to 15:1. The conductive material according to claim 1, wherein the conductive particles are solder particles. The conductive material according to claim 1 or 2, wherein a carboxyl group exists on the outer surface of the conductive particles. The conductive material according to claim 1 or 2, wherein the thermosetting compound includes a thermosetting compound having a triazine skeleton. The conductive material according to claim 1 or 2, comprising insulating particles not adhering to the surface of the conductive particles. The conductive material according to claim 1 or 2, wherein the conductive particles have an average particle diameter of 1 μm or more and 40 μm or less. The conductive material according to claim 1 or 2, wherein the content of the conductive particles is 10% by weight or more and 80% by weight or less in 100% by weight of the conductive material. The conductive material according to claim 1 or 2, which is a liquid at 25°C and is a conductive paste. A first connection target member having a first electrode on its surface;
a second connection target member having a 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 claim 1 or 2,
The connection structure in which the said 1st electrode and the said 2nd electrode are electrically connected with the solder in the said electroconductive particle. delete

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