TW201717215A - Electrically conductive material, and connecting structure - Google Patents

Abstract

Provided is an electrically conductive material in which a hardened material has excellent transparency, and in which the hardened material has excellent heat resistance and is therefore resistant to discoloration. The electrically conductive material according to the present invention includes: a plurality of electrically conductive particles comprising solder on an outer surface part of an electrically conductive part; a thermosetting compound; and a thermosetting agent. The thermosetting compound includes thermosetting compounds comprising a thiirane group and a triazine skeleton.

Description

Conductive material and connection structure

The present invention relates to a conductive material comprising conductive particles having 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.

In order to obtain various connection structures, the anisotropic conductive material is used, for example, for connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass)), and connection between a semiconductor wafer and a flexible printed substrate (COF (Chip on Film) , film over-molding)), connection between a semiconductor wafer and a glass substrate (COG (Chip on Glass)), and connection between a flexible printed substrate and a glass epoxy substrate (FOB (Film on Board)) .

When the electrode of the flexible printed circuit board and the electrode of the glass epoxy substrate are electrically connected by the anisotropic conductive material, for example, the anisotropic conductive material containing the conductive particles is placed on the glass epoxy substrate. Next, a flexible printed circuit board is laminated and heated and pressurized. Thereby, the anisotropic conductive material is cured, and the electrodes are electrically connected to each other via the conductive particles to obtain a bonded structure.

In the following Patent Document 1, an anisotropic conductive material containing conductive particles and a resin component that does not end harden at the melting point of the conductive particles is described in Patent Document 1 below. Specific examples of the conductive particles include tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), and cadmium. Metals such as (Cd), gallium (Ga), silver (Ag), and tantalum (Tl), or alloys of such metals.

Patent Document 1 describes a resin heating step in which an anisotropic conductive resin is heated to a temperature higher than a melting point of the conductive particles and the curing of the resin component is not completed, and a resin component which hardens the resin component is hardened. In the step, the electrodes are electrically connected. Moreover, in Patent Document 1, it is described that the temperature distribution shown in FIG. 8 of Patent Document 1 is attached. In Patent Document 1, the conductive particles are melted in the resin component which does not end the curing at the temperature at which the anisotropic conductive resin is heated.

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

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-260131

[Patent Document 2] WO2008/023452A1

The anisotropic conductive paste which previously contains solder powder or conductive particles having a solder layer on the surface has a low transparency of the cured product. Further, there is a case where the heat resistance of the cured product is low, and the cured product exposed to high temperature is discolored.

An object of the present invention is to provide a conductive material which is excellent in transparency of a cured product and which is excellent in heat resistance of a cured product, so that it is not easily discolored. Further, it is an object of the invention to provide a connection structure using the above-mentioned conductive material.

According to a broader aspect of the present invention, there is provided a conductive material comprising a plurality of conductive particles having a solder on a surface portion of a conductive portion, a thermosetting compound, and a heat hardening agent, and wherein the thermosetting compound comprises Has an ethylene sulfide group and three A thermosetting compound of the skeleton.

In a specific aspect of the conductive material of the present invention, the above has an ethylene sulfide group and three The melting point of the thermosetting compound of the skeleton is 140 ° C or higher.

In a specific aspect of the conductive material of the present invention, the conductive material comprises a different one from the group having an ethylene sulfide group and three A thermosetting compound of a thermosetting compound of a skeleton.

In a specific aspect of the conductive material of the present invention, the conductive particles have an acid value of 0.1 mg/KOH or more and 10 mg/KOH or less.

In a particular aspect of the electrically conductive material of the present invention, the electrically conductive material comprises a flux.

In a specific aspect of the conductive material of the present invention, the flux is a flux having a mercaptoamine group and an aromatic skeleton, or has a mercaptoamine group and has a pKa of 9.5 or less as a carboxylic acid or a carboxylic acid anhydride. A flux of a reactant of an amine based compound.

In a particular aspect of the electrically conductive material of the present invention, the flux is solid at 25 °C.

In a particular aspect of the electrically conductive material of the present invention, the electrically conductive material comprises a carbodiimide compound.

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

In a specific aspect of the conductive material of the present invention, the conductive material includes insulating particles that are not attached to the surface of the conductive particles.

In a specific aspect of the conductive material of the present invention, the conductive particles have an average particle diameter of 1 μm or more and 40 μm or less.

In a specific aspect of the conductive material of the present invention, the conductive particles are contained in an amount of 10% by weight or more and 80% by weight or less based on 100% by weight of the conductive material.

In a specific aspect of the conductive material of the present invention, the conductive material is at 25 ° C The bottom is liquid and is a conductive paste.

According to a broader aspect of the present invention, a connection structure comprising: a first connection member having at least one first electrode on a surface thereof; and a second connection member having at least one on a surface thereof a second electrode; and a connection portion that connects the first connection target member and the second connection target member; wherein the material of the connection portion is the conductive material, and the first electrode and the second electrode are in the connection portion The solder portion is electrically connected.

In a specific aspect of the connection structure of the present invention, when the first electrode and the second electrode are opposed to each other along the laminated direction of the first electrode, the connection portion, and the second electrode A solder portion in the connection portion is disposed at 50% or more of an area of 100% of a portion of the first electrode and the second electrode facing each other.

The conductive material of the present invention contains a plurality of conductive particles, a thermosetting compound, and a heat hardening agent having solder on a surface portion of the conductive portion, and the thermosetting compound contains an ethylene sulfide group and three Since the thermosetting compound of the skeleton is excellent in transparency and the heat resistance of the cured product is excellent, it is not easily discolored.

1‧‧‧Connection structure

1X‧‧‧Connection structure

2‧‧‧1st connection object component

2a‧‧‧1st electrode

3‧‧‧2nd connection object component

3a‧‧‧2nd electrode

4‧‧‧Connecting Department

4A‧‧‧ solder department

4B‧‧‧ Hardened Parts

4X‧‧‧Connecting Department

4XA‧‧‧ solder department

4XB‧‧‧ Hardened Parts Department

11‧‧‧Electrical materials

11A‧‧‧ solder particles (conductive particles)

11B‧‧‧ thermosetting ingredients

21‧‧‧Electrical particles (solder particles)

31‧‧‧Electrical particles

32‧‧‧Substrate particles

33‧‧‧Electrically conductive parts (with conductive parts of solder)

33A‧‧‧2nd Conductive Department

33B‧‧‧ solder department

41‧‧‧Electrical particles

42‧‧‧ solder department

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

2(a) to 2(c) are cross-sectional views for explaining respective steps of an example of a method of manufacturing a bonded structure using a conductive material according to an embodiment of the present invention.

Fig. 3 is a cross-sectional view showing a variation of the connection structure.

Fig. 4 is a cross-sectional view showing a first example of conductive particles which can be used in a conductive material.

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

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

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

(conductive material)

The conductive material of the present invention comprises a plurality of conductive particles and a binder. The conductive particles have a conductive portion. The conductive particles have solder on the outer surface portion of the conductive portion. The solder is included in the conductive portion and is part or all of the conductive portion. The binder is a component other than the conductive particles contained in the conductive material.

The conductive material of the present invention contains a thermosetting component as the above binder. The thermosetting component contains a thermosetting compound and a thermosetting agent.

In the conductive material of the present invention, the thermosetting compound contains an episulfide group and three A thermosetting compound of the skeleton.

In the present invention, since the above configuration is provided, the transparency of the cured product can be improved, and the heat resistance of the cured product is excellent. Therefore, the cured product is less likely to be discolored even when exposed to a high temperature.

Further, in the present invention, even if the electrode width is narrow, the solder in the conductive particles can be efficiently disposed on the electrode. In the case where the electrode width is narrow, there is a tendency that the solder of the conductive particles is less likely to accumulate on the electrode. However, in the present invention, even if the electrode width is narrow, the solder can be sufficiently concentrated on the electrode. In the present invention, since the above-described configuration is provided, when the electrodes are electrically connected to each other, the solder in the conductive particles is likely to be located between the electrodes facing up and down, and the solder in the conductive particles can be efficiently disposed. On the electrode (line). Further, in the present invention, when the electrode width is wide, the solder in the conductive particles is further efficiently disposed on the electrode.

Further, one of the solders in the conductive particles is less likely to be disposed in a region (gap) where the electrode is not formed, and the amount of solder disposed in the region where the electrode is not formed can be made relatively small. In the present invention, the solder not located between the opposing electrodes can be efficiently moved to between the opposite electrodes. Therefore, the conduction reliability between the electrodes can be improved. Moreover, the electrical connection between the electrodes adjacent in the lateral direction which should not be connected can be prevented, and the insulation reliability can be improved.

Further, in the present invention, the heat resistance of the cured product of the conductive material can be improved. Particularly in the case where the optical semiconductor device uses a conductive material, it generates heat upon irradiation of light, and the cured material of the conductive material is exposed to a high temperature. Since the conductive material of the present invention is excellent in heat resistance of the cured product, it can be preferably used in an optical semiconductor device. Especially due to the use of ethylene sulfide groups and three Since the skeleton is a thermosetting compound, the heat resistance of the cured material of the conductive material is increased.

Further, in the present invention, the refractive index of the cured product of the conductive material can be increased. Especially in the present invention, since the use has an ethylenethio group and three Since the skeleton is a thermosetting compound, the refractive index of the cured material of the conductive material is increased. In view of further increasing the refractive index of the cured product of the conductive material, the thermosetting compound preferably contains three a thermosetting compound of a skeleton, more preferably comprising an ethylene sulfide group and three a thermosetting compound of a skeleton, in the present invention, the thermosetting compound contains an episulfide group and three A thermosetting compound of the skeleton. The refractive index of the thermosetting compound is preferably 1.75 or more, more preferably 1.8 or more, and is preferably 1.9 or less, more preferably 1.85 or less. When the refractive index of the thermosetting compound is at least the above lower limit, the refractive index of the cured product of the conductive material can be further increased.

The refractive index of the above thermosetting compound can be measured using a Kalnew precision refractometer. As the Kalnew precision refractometer, for example, "KPR-3000" manufactured by Shimadzu Corporation can be used.

Further, in the present invention, the water absorption rate of the cured product of the conductive material can be lowered. Especially in the present invention, since the use has an ethylenethio group and three Since the skeleton is a thermosetting compound, the water absorption rate of the cured product of the conductive material is lowered. From the viewpoint of further reducing the water absorption rate of the cured product of the conductive material, the above thermosetting compound preferably contains three a thermosetting compound of a skeleton, more preferably comprising an ethylene sulfide group and three a thermosetting compound of a skeleton, in the present invention, the thermosetting compound contains an episulfide group and three A thermosetting compound of the skeleton. The water absorption rate of the above thermosetting compound is preferably 2% or less, more preferably 1.5% or less. When the water absorption of the thermosetting compound is at most the above upper limit, the water absorption of the cured product of the conductive material can be further reduced. The lower limit of the water absorption rate of the above thermosetting compound is not particularly limited. The water absorbing rate of the above thermosetting compound may be 0.1% or more. From the viewpoint of further reducing the water absorption rate of the cured product of the conductive material, the water absorbing rate of the above thermosetting compound is preferably low.

The water absorption rate of the above thermosetting compound can be measured as follows.

5 g of the thermosetting compound was placed in a moisture meter, and the weight after drying at 105 ° C for 5 hours was measured, whereby the water absorption ratio was calculated. As the moisture meter, for example, "MOC63u" manufactured by Shimadzu Corporation can be used.

Further, in the present invention, the positional deviation between the electrodes can be prevented. In the present invention, when the second connection member is placed on the first connection member in which the conductive material is disposed on the upper surface, the alignment of the electrode of the first connection member and the electrode of the second connection member is shifted. In the case where the first connection target member and the second connection target member are overlapped, the offset can be corrected, and the electrode of the first connection target member and the electrode of the second connection target member can be connected (self-aligned) Quasi-effect).

In order to further efficiently dispose the solder on the electrode, the above conductive material is preferably liquid at 25 ° C, and is preferably a conductive paste. In order to further efficiently dispose the solder on the electrode, the viscosity (η25) of the conductive material at 25 ° C is preferably 10 Pa ‧ or more, more preferably 50 Pa ‧ s or more, further preferably 100 Pa ‧ or more, and It is preferably 800 Pa ‧ or less, more preferably 600 Pa ‧ or less, and still more preferably 500 Pa ‧ or less. The above viscosity (η25) can be appropriately adjusted by the type of the blending component and the blending amount. Moreover, by using a filler, the viscosity can be relatively increased.

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

The above conductive material may be used in the form of a conductive paste, a conductive film or the like. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. Will guide From the viewpoint that the solder in the electric particles is further efficiently disposed on the electrode, the conductive material is preferably a conductive paste. The above conductive material can be preferably used for electrical connection of electrodes. The above conductive material is preferably a circuit connecting material.

Hereinafter, each component contained in the above-mentioned conductive material will be described.

(conductive particles)

The conductive particles electrically connect the electrodes of the connection member. The conductive particles have solder on the outer surface portion of the conductive portion. The conductive particles may be solder particles formed of solder. The solder particles have solder on the outer surface portion of the conductive portion. The central portion of the solder particles and the outer surface portion of the conductive portion are each formed of solder. The solder particles are the central portion of the solder particles and the outer surface of the conductive particles are solder particles. The conductive particles may have substrate particles and a conductive portion disposed on a surface of the substrate particles. In this case, the conductive particles have solder on the outer surface portion of the conductive portion.

In addition, when using the conductive particles including the substrate particles not formed of the solder and the solder portion disposed on the surface of the substrate particles, the conductive particles are less likely to be used than when the solder particles are used. Since the conductive particles are less likely to be welded to each other on the electrode, the conductive particles that have moved to the electrode tend to move outside the electrode, and the effect of suppressing the positional shift between the electrodes tends to be lowered. Therefore, the conductive particles are preferably solder particles formed of solder.

From the viewpoint of effectively reducing the connection resistance in the bonded structure and effectively suppressing the generation of voids, it is preferred that a carboxyl group or an amine group be present on the outer surface (the outer surface of the solder) of the conductive particles. A carboxyl group is present, preferably an amine group. Preferably, the group containing a carboxyl group or an amine group is covalently bonded to the outer surface of the above conductive particle via a Si-O bond, an ether bond, an ester bond or a group represented by the following formula (X) (outer surface of the solder) ). The group containing a carboxyl group or an amine group may also contain both a carboxyl group and an amine group. Further, in the following formula (X), the right end portion and the left end portion indicate a bonding portion.

A hydroxyl group is present on the surface of the solder. By covalently bonding the hydroxyl group to a group containing a carboxyl group, a bond stronger than the bonding by other coordinate bonds (chelating coordination) can be formed, so that the connection resistance between the electrodes can be reduced. And conductive particles that suppress the generation of voids.

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

From the viewpoint of effectively reducing the connection resistance in the bonded structure and effectively suppressing the generation of voids, the above-mentioned conductive particles are preferably obtained by using a functional group having a reactivity with a hydroxyl group and a carboxyl group or The amine group compound (hereinafter sometimes referred to as the compound X) reacts a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group. In the above reaction, a covalent bond is formed. By reacting a hydroxyl group on the surface of the solder with a functional group reactive with a hydroxyl group in the above compound X, conductive particles having a carboxyl group or an amine group covalently bonded to the surface of the solder can be easily obtained, and can also be obtained. A solder particle comprising a carboxyl group or an amine group covalently bonded to a solder surface via an ether bond or an ester bond. By reacting the hydroxyl group on the surface of the solder with the functional group reactive with the hydroxyl group, the compound X can be chemically bonded to the surface of the solder in a covalently bonded form.

Examples of the functional group reactive with a hydroxyl group include a hydroxyl group, a carboxyl group, an ester group, and a carbonyl group. It is preferably a hydroxyl group or a carboxyl group. The above functional group reactive with a hydroxyl group may be hydroxy The base may also be a carboxyl group.

Examples of the compound having a functional group reactive with a hydroxyl group include acetopropionic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, and 5-oxohexanoic acid. 3-hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4 -Phenylbutyric acid, citric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, 9-hexadecanoic acid, heptadecanoic acid, stearic acid, oleic acid, oil Acid, linoleic acid, (9,12,15)-linolenic acid, nonadecanoic acid, arachidic acid, sebacic acid and dodecanedioic acid. Preferred is glutaric acid or glycolic acid. The above-mentioned compound having a functional group reactive with a hydroxyl group may be used singly or in combination of two or more. The above compound having a functional group reactive with a hydroxyl group is preferably a compound having at least one carboxyl group.

The above compound X preferably has a fluxing action, and the above compound X preferably has a fluxing action in a state of being bonded to the surface of the solder. The compound having a fluxing action can remove the oxide film on the surface of the solder and the oxide film on the surface of the electrode. The carboxyl group has a fluxing effect.

Examples of the compound having a fluxing action include acetonitrile, glutaric acid, glycolic acid, succinic acid, 5-oxohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, and 3-mercaptopropylidene. Acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, and the like. Preferred is glutaric acid or glycolic acid. The above-mentioned compound having a fluxing action may be used alone or in combination of two or more.

The functional group reactive with a hydroxyl group in the above compound X is preferably a hydroxyl group or a carboxyl group from the viewpoint of effectively reducing the connection resistance in the bonded structure and effectively suppressing the generation of pores. The above functional group which can react with a hydroxyl group in the above compound X may be a hydroxyl group or a carboxyl group. In the case where the functional group reactive with a hydroxyl group is a carboxyl group, the compound X preferably has at least two carboxyl groups. Conductive particles having a carboxyl group-containing group covalently bonded to the surface of the solder can be obtained by reacting a part of the carboxyl group of a compound having at least two carboxyl groups with a hydroxyl group on the surface of the solder.

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

Further, in the method for producing the conductive particles, it is preferred to use conductive particles, and to mix the conductive particles, the compound having a functional group capable of reacting with a hydroxyl group and a carboxyl group, the catalyst, and the solvent. heating. Conductive particles having a carboxyl group-containing group covalently bonded to the surface of the solder can be further easily obtained by a mixing and heating step.

Examples of the solvent include an alcohol solvent such as methanol, ethanol, propanol or butanol, or acetone, methyl ethyl ketone, ethyl acetate, toluene or xylene. The above solvent is preferably an organic solvent, more preferably toluene. These solvents may be used alone or in combination of two or more.

Examples of the catalyst include p-toluenesulfonic acid, benzenesulfonic acid, and 10-camphorsulfonic acid. The above catalyst is preferably p-toluenesulfonic acid. The above catalysts may be used alone or in combination of two or more.

It is preferred to carry out heating at the time of the above mixing. The heating temperature is preferably 90 ° C or higher, more preferably 100 ° C or higher, and is preferably 130 ° C or lower, more preferably 110 ° C or lower.

The conductive particles are preferably subjected to an isocyanate compound and reacting a hydroxyl group on the surface of the solder with the isocyanate compound from the viewpoint of effectively reducing the connection resistance in the bonded structure and effectively suppressing the generation of voids. And get. In the above reaction, a covalent bond is formed. Conductive particles in which a nitrogen atom derived from an isocyanate group is covalently bonded to a solder surface can be easily obtained by reacting a hydroxyl group on the surface of the solder with the above isocyanate compound. By reacting the hydroxyl group on the surface of the solder with the isocyanate compound, the isocyanate group-derived group can be chemically bonded to the surface of the solder in a covalently bonded form.

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

The compound having at least one carboxyl group preferably has a plurality of carboxyl groups from the viewpoint of effectively reducing the connection resistance in the bonded structure and effectively suppressing the generation of voids.

Examples of the above isocyanate compound include diphenylmethane-4,4'-diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI). Wait. Isocyanate compounds other than these may also be used. After reacting the compound with the surface of the solder, the remaining isocyanate group is reacted with a compound having a carboxyl group reactive with the remaining isocyanate group, whereby a carboxyl group can be introduced into the surface of the solder via the group represented by the formula (X).

As the above isocyanate compound, a compound having an unsaturated double bond and having an isocyanate group can be used. For example, 2-propenyloxyethyl isocyanate and 2-isocyanate ethyl methacrylate are mentioned. After reacting the isocyanate group of the compound with the surface of the solder, a compound having a functional group reactive with the remaining unsaturated double bond and having a carboxyl group is reacted, whereby the group represented by the formula (X) can be used. A carboxyl group is introduced to the surface of the solder.

Examples of the decane coupling agent include 3-isocyanatepropyltriethoxydecane ("KBE-9007" manufactured by Shin-Etsu Silicones Co., Ltd.) and 3-isocyanatepropyltrimethoxydecane (manufactured by MOMENTIVE Co., Ltd.). "Y-5187") and so on. The above decane coupling agents may be used alone or in combination of two or more.

Examples of the compound having at least one carboxyl group include acetopropionic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-oxohexanoic acid, and 3- Hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-benzene Butyric acid, citric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, 9-hexadecanoic acid, heptadecanoic acid, stearic acid, oleic acid, isooleic acid, Linseed acid, (9,12,15)-linolenic acid, nonadecanoic acid, arachidic acid, azelaic acid and dodecanedioic acid. Preferred is glutaric acid, adipic acid or glycolic acid. The compound having at least one carboxyl group may be used alone or in combination of two or more.

After the hydroxyl group on the surface of the solder is reacted with the isocyanate compound by using the above isocyanate compound, a part of the carboxyl group of a compound having a plurality of carboxyl groups is reacted with a hydroxyl group on the surface of the solder, whereby a group containing a carboxyl group remains.

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

As a specific manufacturing method of the said electroconductive particle, the following methods are mentioned. The conductive particles are dispersed in an organic solvent, and a decane coupling agent having an isocyanate group is added. Thereafter, a reaction catalyst of a hydroxyl group and an isocyanate group on the surface of the solder of the conductive particles is used to covalently bond the decane coupling agent to the surface of the solder. Next, a hydroxyl group is produced by hydrolyzing an alkoxy group bonded to a ruthenium atom of a decane coupling agent. The resulting hydroxyl group is reacted with a carboxyl group of a compound having at least one carboxyl group.

Moreover, as a specific manufacturing method of the said electroconductive particle, the following methods are mentioned. The conductive particles are dispersed in an organic solvent, and a compound having an isocyanate group and an unsaturated double bond is added. Thereafter, the hydroxyl group and isocyanic acid on the surface of the solder using conductive particles The ester-based reaction catalyst forms a covalent bond. Thereafter, a compound having an unsaturated double bond and a carboxyl group is allowed to react with the introduced unsaturated double bond.

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

The compound having at least one carboxyl group is preferably a compound represented by the following formula (1) from the viewpoint of effectively reducing the connection resistance in the bonded structure and effectively suppressing the generation of voids. The compound represented by the following formula (1) has a fluxing action. Further, the compound represented by the following formula (1) has a fluxing action in a state of being introduced into the surface of the solder.

In the above formula (1), X represents a functional group reactive 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 above organic group is preferably a divalent hydrocarbon group. Regarding the organic group, a carboxyl group or a hydroxyl group may be bonded to a divalent hydrocarbon group. The compound represented by the above formula (1) contains, for example, citric acid.

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

[Chemical 3]

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

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

Preferably, a base represented by the following formula (2A) or the following formula (2B) is bonded to the surface of the solder. It is preferable that the surface represented by the following formula (2A) is bonded to the surface of the solder, and it is more preferable to bond the group represented by the following formula (2B). In the following formula (2A) and the following formula (2B), the left end portion indicates a bonding portion.

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

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

The molecular weight of the compound having at least one carboxyl group is preferably 10,000 or less, more preferably 1,000 or less, still more preferably 500 or less from the viewpoint of improving the wettability of the solder surface.

When the compound having at least one carboxyl group is not a polymer and the structural formula of the compound having at least one carboxyl group is specified, the molecular weight may be calculated based on the structural formula. The molecular weight. Further, in the case where the compound having at least one carboxyl group is a polymer, it means a weight average molecular weight.

In order to effectively improve the cohesiveness of the conductive particles during the conductive connection, the conductive particles preferably have a conductive particle body and an anionic polymer disposed on the surface of the conductive particle body. The conductive particles are preferably obtained by subjecting the conductive particles to a surface treatment by using an anionic polymer or a compound which is an anionic polymer. The conductive particles are preferably surface treated materials using an anionic polymer or a compound which is an anionic polymer. The anionic polymer and the compound which is the above anionic polymer may be used alone or in combination of two or more. The above anionic polymer is a polymer having an acidic group.

As a surface for treating the surface of conductive particles with an anionic polymer The method includes, for example, a (meth)acrylic polymer obtained by copolymerizing (meth)acrylic acid, a polyester polymer synthesized from a dicarboxylic acid and a diol and having a carboxyl group at both terminals, by a polymer obtained by intermolecular dehydration condensation reaction of a dicarboxylic acid and having a carboxyl group at both terminals, a polyester polymer synthesized from a dicarboxylic acid and a diamine and having a carboxyl group at both terminals, and a modified polyvinyl alcohol having a carboxyl group (poval ("GOHSENX T" manufactured by Nippon Synthetic Chemical Co., Ltd.) or the like as an anionic polymer, and reacts a carboxyl group of the anionic polymer with a hydroxyl group on the surface of the conductive particle body.

Examples of the anion portion of the anionic polymer include the above-mentioned carboxyl group, and examples thereof include a toluenesulfonyl group (pH ₃ CC ₆ H ₄ S(=O) ₂ -), a sulfonate ion group (-SO ₃ ^- ), and Phosphate ion group (-PO ₄ ^- ) and the like.

In addition, as another method of the surface treatment, a method of using a functional group having a functional group reactive with a hydroxyl group on the surface of the conductive particle and further having a functional group capable of polymerization by addition or condensation reaction is used. The compound is polymerized on the surface of the conductive particle body. Examples of the functional group that reacts with the hydroxyl group on the surface of the conductive particle body include a carboxyl group and an isocyanate group. Examples of the functional group to be polymerized by addition or condensation reaction include a hydroxyl group, a carboxyl group, and an amine group. And (meth) acrylonitrile.

The weight average molecular weight of the above anionic polymer is preferably 2,000 or more, more preferably 3,000 or more, and is preferably 10,000 or less, more preferably 8,000 or less. When the weight average molecular weight is at least the above lower limit and not more than the above upper limit, a sufficient amount of charge and solderability can be introduced into the surface of the conductive particles. Thereby, the cohesiveness of the conductive particles can be effectively improved at the time of conductive connection, and the oxide film on the electrode surface can be effectively removed when the connection member is connected.

When the weight average molecular weight is not less than the above lower limit and not more than the above upper limit, the anionic polymer is easily disposed on the surface of the conductive particle body, and the cohesiveness of the conductive particles can be effectively improved during the conductive connection, and the efficiency can be further improved. Conductive particles Configured on the electrode.

The above weight average molecular weight means a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

The weight average molecular weight of the polymer obtained by surface-treating the main body of the conductive particles by using the compound which becomes an anionic polymer can be obtained by dissolving the solder in the conductive particles without utilizing the polymer. After the conductive particles are removed by decomposing dilute hydrochloric acid or the like, the weight average molecular weight of the remaining polymer is measured.

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

Fig. 4 is a cross-sectional view showing a first example of conductive particles which can be used in a conductive material.

The conductive particles 21 shown in Fig. 4 are solder particles. The entirety of the conductive particles 21 is formed of solder. The conductive particles 21 do not have a substrate particle as a core but not a core-shell particle. The central portion of the conductive particles 21 and the outer surface portion of the conductive portion are formed of solder.

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

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

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

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

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

Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. Preferably, the substrate particles are gold removal The substrate particles other than the genus are preferably resin particles, inorganic particles other than the metal particles, or organic-inorganic hybrid particles. The substrate particles may be copper particles. The substrate particles may have a core and a shell disposed on a surface of the core, and may be core-shell particles. The above-mentioned core may be an organic core, and the above shell may be an inorganic shell.

As the resin for forming the above resin particles, various organic materials can be preferably 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; and polymethacrylic acid; Acrylic resin such as methyl ester 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, polyfluorene, polyphenylene ether, polyacetal, polyimine, polyamidimide , polyetheretherketone, polyether oxime, divinylbenzene polymer, and divinylbenzene copolymer. Examples of the divinylbenzene-based copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene-(meth)acrylate copolymer. Since the hardness of the resin particles can be easily controlled to a suitable range, the resin for forming the resin particles is preferably obtained by polymerizing one or two or more kinds of polymerizable monomers having an ethylenically unsaturated group. The polymer.

When the polymerizable monomer having an ethylenically unsaturated group is polymerized to obtain the above resin particles, examples of the polymerizable monomer having an ethylenically unsaturated group include a non-crosslinkable monomer and cross-linking. Sexual monomer.

Examples of the non-crosslinkable monomer include a styrene monomer such as styrene or α-methylstyrene, and a carboxyl group such as (meth)acrylic acid, maleic acid or maleic anhydride. Monomer; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (a) Base) lauryl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylate Alkyl (meth) acrylate compound such as ester; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate a (meth) acrylate compound containing an oxygen atom; a nitrile group-containing monomer such as (meth)acrylonitrile; a vinyl ether compound such as methyl vinyl ether, ethyl vinyl ether or propyl vinyl ether; vinyl acetate; Acid vinyl ester compounds such as vinyl butyrate, vinyl laurate, vinyl stearate; unsaturated hydrocarbons such as ethylene, propylene, isoprene, butadiene; trifluoromethyl (meth)acrylate, (a) A halogen-containing monomer such as pentafluoroethyl acrylate, vinyl chloride, vinyl fluoride or chlorostyrene.

Examples of the crosslinkable monomer include tetramethylol methane tetra(meth)acrylate, tetramethylol methane tri(meth)acrylate, and tetramethylolmethane di(meth)acrylate. Ester, trimethylolpropane tri(meth) acrylate, dipentaerythritol hexa(meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri(meth) acrylate, glycerol di(methyl) Acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, 1,4- Polyfunctional (meth) acrylate compounds such as butanediol di(meth) acrylate; triallyl (iso) cyanurate, triallyl trimellitate, divinyl benzene, diene phthalate Butane-containing, diallyl acrylamide, diallyl ether, γ-(meth) propylene methoxy propyl trimethoxy decane, trimethoxy decyl styrene, vinyl trimethoxy decane, etc. Monomers, etc.

The term "(meth)acrylate" means acrylate and methacrylate. The term "(meth)acrylic" means acrylic acid and methacrylic acid. The term "(meth)acrylonitrile" means acryl fluorenyl and methacryl fluorenyl.

The above resin particles can be obtained by polymerizing the above polymerizable monomer having an ethylenically unsaturated group by a known method. The method may, for example, be a method in which suspension polymerization is carried out in the presence of a radical polymerization initiator; and a monomer which is swelled together with a radical polymerization initiator using non-crosslinked seed particles and The method of polymerization.

The substrate particles are inorganic particles or organic-inorganic hybrid particles other than metals. In the case of the inorganic material for forming the substrate particles, examples thereof include cerium oxide, aluminum oxide, barium titanate, zirconia, and carbon black. The above inorganic substance is preferably not a metal. The particles formed of the above-mentioned cerium oxide are not particularly limited, and for example, after the crosslinked polymer particles are formed by hydrolyzing a hydrazine compound having two or more hydrolyzable alkoxyalkylene groups, The particles obtained by calcination as needed. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles obtained by crosslinking alkoxysilane alkyl polymer and an acrylic resin.

The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. The above core is preferably an organic core. The above shell is preferably an inorganic shell. The substrate particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core, from the viewpoint of effectively reducing the connection resistance between the electrodes.

Examples of the material for forming the organic core include a resin or the like for forming the resin particles.

Examples of the material for forming the inorganic shell include inorganic materials for forming the substrate particles. The material for forming the above inorganic shell is preferably cerium oxide. The inorganic shell is preferably formed by forming a metal alkoxide into a shell on the surface of the core by a sol-gel method, and then sintering the shell. The metal alkoxide is preferably a decane alkoxide. The above inorganic shell is preferably formed of a decane alkoxide.

The particle diameter of the core is preferably 0.5 μm or more, more preferably 1 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less, still more preferably 40 μm or less, still more preferably 30 μm or less, and most preferably 15 μm or less. When the particle diameter of the core is not less than the above lower limit and not more than the above upper limit, conductive particles more suitable for electrical connection between the electrodes can be obtained, and the substrate particles can be preferably used for the use of the conductive particles. For example, when the particle diameter of the core is not less than the above lower limit and not more than the above upper limit, when the conductive particles are connected between the electrodes, the contact area between the conductive particles and the electrode is sufficiently increased, and the substrate particles are grown. When the conductive portion is formed on the surface, it is difficult to form agglomerated conductive particles. Moreover, the interval between the electrodes connected via the conductive particles does not become excessively large, and the conductive portion is less likely to be peeled off from the surface of the substrate particles.

The particle diameter of the above-mentioned core means a diameter when the core is a true spherical shape, and refers to a maximum diameter when the core is a shape other than a true spherical shape. Further, the particle diameter of the core means an average particle diameter obtained by measuring a core by an arbitrary particle diameter measuring device. For example, a particle size distribution measuring machine using the principles of laser light scattering, resistance value change, and image analysis after imaging can be used.

The thickness of the above shell is preferably 100 nm or more, more preferably 200 nm or more, and is preferably 5 μm or less, more preferably 3 μm or less. When the thickness of the shell is not less than the above lower limit and not more than the above upper limit, conductive particles more suitable for electrical connection between the electrodes can be obtained, and the substrate particles can be preferably used for the use of the conductive particles. The thickness of the above shell is the average thickness of each of the substrate particles. The thickness of the above shell can be controlled by the control of the sol-gel method.

In the case where the substrate particles are metal particles, examples of the metal for forming the metal particles include silver, copper, nickel, rhodium, gold, and titanium. In the case where the substrate particles are metal particles, the metal particles are preferably copper particles. However, it is preferred that the substrate particles are not metal particles.

The particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 1 μm or more, further preferably 1.5 μm or more, particularly preferably 2 μm or more, and preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 40 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less, still more preferably 5 μm or less, and most preferably 3 μm or less. When the particle diameter of the substrate particles is at least the above lower limit, the contact area between the conductive particles and the electrode is increased, so that the conduction reliability between the electrodes can be further improved, and the connection resistance between the electrodes connected via the conductive particles can be further reduced. . When the particle diameter of the substrate particles is not more than the above upper limit, it is easy to sufficiently compress the conductive particles, and the connection resistance between the electrodes can be further reduced, and the interval between the electrodes can be further reduced.

The particle diameter of the substrate particles is a diameter when the substrate particles are in a true spherical shape, and indicates a maximum diameter when the substrate particles are not in a true spherical shape.

The particle diameter of the substrate particles is particularly preferably 2 μm or more and 5 μm or less. When the particle diameter of the substrate particles is in the range of 2 μm or more and 5 μm or less, the interval between the electrodes can be further reduced, and even if the thickness of the conductive layer is increased, a small amount of conductive particles can be obtained.

A method of forming a conductive portion on the surface of the substrate particle, and a method of forming a solder portion on the surface of the substrate particle or the surface of the second conductive portion are not particularly limited. Examples of the method of forming the conductive portion and the solder portion include a method using electroless plating, a method using electroplating, a method using physical collision, a method using mechanochemical reaction, and physical vapor deposition or physical adsorption. And a method of applying a metal powder or a solder paste containing a metal powder and a binder to a surface of a substrate particle. It is preferred to use a method of electroless plating, electroplating or physical collision. Examples of the method using physical vapor deposition include vacuum deposition, ion plating, and ion sputtering. Further, in the above method of utilizing physical collision, for example, Theta Composer (manufactured by Deshou Works Co., Ltd.) or the like can be used.

The melting point of the substrate particles is preferably higher than the melting points of the conductive portion and the solder portion. The melting point of the substrate particles is preferably more than 160 ° C, more preferably more than 300 ° C, still more preferably more than 400 ° C, and even more preferably more than 450 ° C. Further, the substrate particles may have a melting point of less than 400 °C. The base material particles may have a melting point of 160 ° C or lower. The softening point of the substrate particles is preferably 260 ° C or higher. The substrate particles may have a softening point of less than 260 °C.

The conductive particles may have a single layer solder portion. The conductive particles may have a plurality of layers of conductive portions (solder portions, second conductive portions). In other words, in the conductive particles, two or more conductive portions may be laminated. When the conductive portion is two or more layers, the conductive particles preferably have solder on the outer surface portion of the conductive portion.

The above solder is preferably a metal having a melting point of 450 ° C or less (low melting point metal). The solder portion is preferably a metal layer (low melting point metal layer) having a melting point of 450 ° C or lower. The above low melting point The metal layer comprises a layer of a low melting point metal. The solder in the conductive particles is preferably a metal particle (low melting point metal particle) having a melting point of 450 ° C or lower. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal means a metal having a melting point of 450 ° C or less. The melting point of the low melting point metal is preferably 300 ° C or lower, more preferably 160 ° C or lower. Further, it is preferable that the solder in the conductive particles contains tin. The content of tin is preferably 30% by weight or more, and more preferably 40% by weight or more, based on 100% by weight of the metal contained in the solder portion and 100% by weight of the metal contained in the solder in the conductive particles. Further, it is preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the content of tin contained in the solder in the conductive particles is at least the above lower limit, the conduction reliability of the conductive particles and the electrode is further increased.

In addition, a high-frequency inductively coupled plasma-based spectroscopic spectrometer ("ICP-AES" manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer ("EDX-800HS" manufactured by Shimadzu Corporation) can be used. And the measurement is performed.

By using the conductive particles having solder on the outer surface portion of the conductive portion, the solder is melted and bonded to the electrodes, and the solder conducts between the electrodes. For example, since the solder and the electrode are easily in surface contact instead of point contact, the connection resistance is lowered. Further, by using the conductive particles having solder on the outer surface portion of the conductive portion, the bonding strength between the solder and the electrode is increased, and as a result, peeling of the solder and the electrode is less likely to occur, and the conduction reliability is effectively increased.

The low melting point metal constituting the solder portion and the solder particles is not particularly limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. The low melting point metal is preferably tin, tin-silver alloy, tin-silver-copper alloy, tin-bismuth alloy, or tin-indium alloy in terms of excellent wettability of the electrode. More preferably, it is a tin-bismuth alloy or a tin-indium alloy.

The material constituting the solder (solder portion) is preferably based on JIS Z3001: welding terminology. The liquidus is a filler metal of 450 ° C or less. Examples of the composition of the solder include a metal composition containing zinc, gold, silver, lead, copper, tin, antimony, indium, or the like. A tin-indium system (117 ° C eutectic) or a tin-lanthanide (139 ° C eutectic) having a low melting point and no lead is preferable. That is, the solder is preferably free from lead, and is preferably a solder containing tin and indium or a solder containing tin and antimony.

In order to further improve the bonding strength between the solder and the electrode, the solder in the conductive particles may contain nickel, copper, lanthanum, aluminum, zinc, iron, gold, titanium, phosphorus, lanthanum, cerium, cobalt, lanthanum, manganese, chromium, Metals such as molybdenum and palladium. Further, from the viewpoint of further improving the bonding strength between the solder and the electrode, the solder in the conductive particles preferably contains nickel, copper, ruthenium, 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 the metal for improving the bonding strength is preferably 0.0001% by weight of the solder in the conductive particles. It is more than weight%, and is preferably 1% by weight or less.

The melting point of the second conductive portion is preferably higher than the melting point of the solder portion. The melting point of the second conductive portion is preferably more than 160 ° C, more preferably more than 300 ° C, still more preferably more than 400 ° C, more preferably more than 450 ° C, more preferably more than 500 ° C, and most preferably more than 600 ° C . Since the solder portion has a low melting point, it melts when electrically connected. Preferably, the second conductive portion does not melt when electrically connected. The conductive particles are preferably used by melting the solder, and it is preferable to use the solder portion by melting. It is preferable to use the solder portion while melting the second conductive portion without melting the solder portion. When the melting point of the second conductive portion is higher than the melting point of the solder portion, the solder portion can be melted without melting the second conductive portion during the conductive connection.

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

Preferably, the second conductive portion contains a metal. Forming the metal of the second conductive portion There is no special limit. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, ruthenium, osmium, iridium, and cadmium, and the like. Further, as the above metal, tin-doped indium oxide (ITO) can be used. The above metals may be used alone or in combination of two or more.

The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer or a gold layer, and further preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably have a nickel layer or a gold layer, and further preferably have a copper layer. By using the conductive particles having the preferred conductive portions for the connection between the electrodes, the connection resistance between the electrodes is further lowered. Further, the solder portion can be formed more easily on the surface of the preferred 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 not less than the above lower limit and not more than the above upper limit, sufficient conductivity can be obtained, and the conductive particles are not excessively hard, and the conductive particles are sufficiently deformed at the time of connection between the electrodes.

The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, and more preferably 100 μm or less, more preferably 50 μm or less, still more preferably 40 μm or less, and particularly preferably It is 30 μm or less. When the conductive particles are at least the above lower limit and not more than the above upper limit, the solder in the conductive particles can be more efficiently disposed on the electrode, and the solder in the conductive particles can be easily disposed between the electrodes and turned on. Reliability is further increased.

The "average particle diameter" of the above conductive particles means a number average particle diameter. The average particle diameter of the conductive particles is determined, for example, by observing any 50 conductive particles by an electron microscope or an optical microscope and calculating an average value.

The coefficient of variation of the particle diameter of the conductive particles is preferably 5% or more, more preferably 10% or more, and is preferably 40% or less, more preferably 30% or less. If the coefficient of variation of the above particle size When it is more than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be further efficiently disposed on the electrode. The coefficient of variation of the particle diameter of the conductive particles may be less than 5%.

The above coefficient of variation (CV value) is represented by the following formula.

CV value (%) = (ρ / Dn) × 100

ρ: standard deviation of the particle size of the conductive particles

Dn: average of the particle diameter of the conductive particles

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

The acid value of the conductive particles is preferably 0.1 mg/KOH or more, more preferably 1 mg/KOH or more, and is preferably 10 mg/KOH or less, more preferably 7 mg/KOH or less. When the acid value is not less than the above lower limit and not more than the above upper limit, the heat resistance of the cured product is further increased, and discoloration of the cured product can be further suppressed.

The above acid value can be measured in the following manner. To the ethanol, phenolphthalein was added, and 50 ml of a solution neutralized with 0.1 N-KOH was added, and 1 g of conductive particles were added, and the mixture was dispersed by ultrasonic treatment, and then titrated with 0.1 N-KOH.

The content of the conductive particles is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, and particularly preferably 20% by weight or more, based on 100% by weight of the conductive material. It is 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 not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be more efficiently disposed on the electrode, and the solder in the conductive particles can be easily disposed between the electrodes. The reliability of conduction is further increased. From the viewpoint of further improving the conduction reliability, the content of the above conductive particles is preferably as large as possible.

(thermosetting compound)

The above thermosetting compound is a compound which can be hardened by heating. As above Examples of the thermosetting compound include an oxetane compound, an epoxy compound, an episulfide compound, a (meth)acrylic compound, a phenol compound, an amine compound, an unsaturated polyester compound, and a polyaminocarboxylic acid. An ester compound, a polyoxymethylene compound, a polyimine compound, or the like. The epoxy compound or the episulfide compound is preferred from the viewpoint of further improving the curing property and viscosity of the conductive material and further improving the connection reliability. These thermosetting compounds may be used alone or in combination of two or more.

In the present invention, the above thermosetting compound comprises an ethylene sulfide group and three A thermosetting compound of the skeleton. By using this specific thermosetting property, the transparency of the cured product is increased, and the heat resistance of the cured product is increased. Moreover, the above thermosetting compound has three The dielectric constant of the skeleton and hardened material is effectively reduced.

As having three The thermosetting compound of the skeleton, which can be cited as three Triglycidyl ether, etc., can be cited as: TEPIC series manufactured by Nissan Chemical Industries Co., Ltd. (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, TEPIC-UC) Wait. The above has an ethylenethio group and three a thermosetting compound of a skeleton, for example, by having the above three It is obtained by converting an epoxy group of a thermosetting compound of a skeleton into an ethylenethio group. Methods for converting an epoxy group to an ethylenethio group are well known.

The above has an ethylenethio group and three The melting point of the thermosetting compound of the skeleton is preferably 140 ° C or higher, more preferably 150 ° C or higher. When the melting point is at least the above lower limit, the conductive particles are further efficiently disposed between the electrodes. The above has an ethylenethio group and three The melting point of the thermosetting compound of the skeleton is preferably equal to or higher than the melting point of the solder in the conductive particles.

The above thermosetting compound may also contain a different from having an ethylenethio group and three A thermosetting compound of a thermosetting compound of a skeleton. The above is different from having an ethylene sulfide group and three The thermosetting compound of the thermosetting compound of the skeleton may be a thermosetting compound having no episulfide group, and may have no three The thermosetting compound of the skeleton may also be an epoxy compound.

An aromatic epoxy compound is mentioned as said epoxy compound. A crystalline epoxy compound such as a resorcinol type epoxy compound, a naphthalene type epoxy compound, a biphenyl type epoxy compound, or a benzophenone type epoxy compound is preferable. It is preferably an epoxy compound which is solid at normal temperature (23 ° C) and has a melting temperature below the melting point of the solder. The melting temperature is preferably 100 ° C or lower, more preferably 80 ° C or lower, and more preferably 40 ° C or higher. By using the above-mentioned preferred epoxy compound, the viscosity is high at the stage of bonding the member to be joined, and when the acceleration is applied by impact such as conveyance, the position of the first connection member and the second connection member can be suppressed. The offset, and the viscosity of the conductive material can be greatly reduced by the heat at the time of hardening, and the aggregation of the solder can be performed efficiently.

The content of the entire thermosetting compound 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, based on 100% by weight of the conductive material. Hereinafter, it is more preferably 98% by weight or less, further preferably 90% by weight or less, and particularly preferably 80% by weight or less. When the content of the thermosetting compound is not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be more efficiently disposed on the electrode, and the positional shift between the electrodes can be further suppressed, thereby further improving the interelectrode. Conduction reliability. From the viewpoint of further improving the impact resistance, the content of the above thermosetting compound is preferably as large as possible.

In the above 100% by weight of the conductive material, the above-mentioned having an ethylenethio group and three The content of the thermosetting compound of the skeleton is preferably 10% by weight or more, more preferably 20% by weight or more, and is preferably 90% by weight or less, more preferably 80% by weight or less. If the above has an ethylenethio group and three When the content of the thermosetting compound of the skeleton is not less than the above lower limit and not more than the above upper limit, the transparency and heat resistance of the cured product are effectively increased.

(hot hardener)

The above-mentioned thermosetting agent thermally hardens the above thermosetting compound. Examples of the thermosetting agent include an imidazole curing agent, a phenol curing agent, a thiol curing agent, an amine curing agent, an acid anhydride curing agent, a thermal cation initiator (thermal cation curing agent), and a thermal radical generating agent. Above heat The hardener may be used singly or in combination of two or more.

The thermosetting agent is preferably an imidazole hardener, a thiol hardener, or an amine hardener from the viewpoint of allowing the conductive material to be further rapidly cured at a low temperature. Moreover, from the viewpoint of improving the storage stability when the thermosetting compound and the above-mentioned thermosetting agent are mixed, the above-mentioned thermosetting agent is preferably a latent curing agent. The latent hardener is preferably a latent imidazole hardener, a latent thiol hardener or a latent amine hardener. Further, the thermal curing agent may be coated with a polymer material such as a polyurethane resin or a polyester resin.

The imidazole curing agent is not particularly limited, and examples thereof include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2. -phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-all three And 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-all three An isocyanuric acid addition product or the like.

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

The solubility parameter of the above thiol hardener is preferably 9.5 or more, and preferably 12 or less. The above solubility parameters are calculated by the Fedors method. For example, the solubility parameter of trimethylolpropane tri-3-mercaptopropionate is 9.6, and the solubility parameter of dipentaerythritol hexa-3-mercaptopropionate is 11.4.

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

Examples of the thermal cation initiator (thermal cation hardener) include a lanthanoid cation curing agent, an oxonium cation curing agent, and a lanthanoid cation curing agent. Examples of the ruthenium-based cation hardener include bis(4-t-butylphenyl)phosphonium hexafluorophosphate. Examples of the oxonium-based cation hardener include trimethyloxonium tetrafluoroborate. As above Examples of the ruthenium-based cationic hardener include tri-p-tolylsulfonium hexafluorophosphate.

The thermal radical generating agent is not particularly limited, and examples thereof include an azo compound and an organic peroxide. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxide include ditributyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature of the above-mentioned thermosetting agent is preferably 50 ° C or more, more preferably 70 ° C or more, further preferably 80 ° C or more, and preferably 250 ° C or less, more preferably 200 ° C or less, and further preferably Below 150 ° C, particularly preferably below 140 ° C. When the reaction initiation temperature of the thermal curing agent is not less than the above lower limit and not more than the above upper limit, the solder is further efficiently disposed on the electrode. The reaction initiation temperature of the above-mentioned thermosetting agent is particularly preferably 80 ° C or more and 140 ° C or less.

The reaction initiation temperature of the thermal curing agent is preferably higher than the melting point of the solder in the conductive particles, more preferably 5 ° C or higher, from the viewpoint of further efficiently disposing the solder on the electrode. Jia is 10°C higher.

The reaction initiation temperature of the above-mentioned thermosetting agent refers to a temperature at which the rise of the heat generation peak in DSC (Differential Scanning Calorimetry) starts.

The content of the above-mentioned thermosetting agent is not particularly limited. The content of the above-mentioned thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, and preferably 200 parts by weight or less, more preferably 100 parts by weight, based on 100 parts by weight of the total of the thermosetting compound. Hereinafter, it is more preferably 75 parts by weight or less. When the content of the thermosetting agent is at least the above lower limit, the conductive material is easily sufficiently cured. When the content of the thermosetting agent is not more than the above upper limit, the remaining heat hardener which does not participate in hardening after curing hardly remains, and the heat resistance of the cured product is further increased.

(flux)

The above conductive paste preferably contains a flux. The solder can be further efficiently disposed on the electrode by using a flux. The flux is not particularly limited. As a flux, it can be Use a flux that is usually used, such as soldering.

Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, a phosphoric acid, a derivative of phosphoric acid, an organic halide, an anthracene, and an organic acid. And turpentine and so on. The flux may be used singly or in combination of two or more.

Examples of the molten salt include ammonium chloride and the like. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid, and glutaric acid. Examples of the rosin include activated rosin and non-activated rosin. The flux is preferably an organic acid or rosin having two or more carboxyl groups. The flux may be an organic acid having two or more carboxyl groups or a rosin. By using an organic acid or rosin having two or more carboxyl groups, the conduction reliability between the electrodes is further increased.

The above rosin is a rosin having rosin acid as a main component. The flux is preferably rosin, more preferably rosin acid. By using the preferred flux, the conduction reliability between the electrodes is further increased.

Preferably, the flux is a flux having a mercaptoamine group and an aromatic skeleton, or a flux having a mercaptoamine group and reacting as a carboxylic acid or a carboxylic anhydride with an amine group-containing compound having a pKa of 9.5 or less. In this case, the storage stability of the conductive material is increased, and the components other than the conductive particles are less likely to excessively flow during the connection between the electrodes, and the adhesion can be improved to improve the conduction reliability.

Preferably, the flux is a flux having a mercaptoamine group and an aromatic skeleton, and is preferably a reactant having a mercaptoamine group and acting as a carboxylic acid or a carboxylic acid anhydride and an amine group-containing compound having a pKa of 9.5 or less. Flux. The flux may be used singly or in combination of two or more.

Further, in the case where the flux is a reactant of a carboxylic acid or a carboxylic anhydride and an amine group-containing compound having a pKa of 9.5 or less, it is not possible to directly specify an amine having a pKa within a specific range by a structure or a property. The range of reactants of the base compound.

The flux is preferably solid at 25 ° C from the viewpoint of further preventing the components other than the conductive particles from flowing more easily during the connection between the electrodes in order to effectively improve the storage stability of the conductive material.

The above flux can be obtained, for example, by reacting a carboxylic acid or a carboxylic acid anhydride with an amine group-containing compound.

Examples of the carboxylic acid or carboxylic acid anhydride include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and malic acid.

Examples of the amine group-containing compound include benzylamine, aniline, and diphenylamine. The amine group-containing compound is preferably an aromatic amine compound from the viewpoint of further preventing the components other than the conductive particles from flowing more easily during the connection between the electrodes in order to effectively improve the storage stability of the conductive material.

The active temperature (melting point) of the flux is preferably 50 ° C or higher, more preferably 70 ° C or higher, further preferably 80 ° C or higher, and preferably 200 ° C or lower, more preferably 190 ° C or lower, more preferably 160. It is preferably 150 ° C or lower, and more preferably 140 ° C or lower. When the activation temperature of the flux is not less than the above lower limit and not more than the above upper limit, the fluxing effect is further effectively exhibited, and the solder is further efficiently disposed on the electrode. The active temperature (melting point) of the above flux is preferably 80 ° C or more and 190 ° C or less. The active temperature (melting point) of the above flux is particularly preferably 80 ° C or more and 140 ° C or less.

Examples of the flux having a living temperature (melting point) of the flux of 80 ° C or more and 190 ° C or less include succinic acid (melting point 186 ° C), glutaric acid (melting point 96 ° C), and adipic acid (melting point 152 ° C). A dicarboxylic acid such as pimelic acid (melting point 104 ° C) or suberic acid (melting point 142 ° C), benzoic acid (melting point 122 ° C), malic acid (melting point 130 ° C), and the like.

Further, the flux has a boiling point of preferably 200 ° C or lower.

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 even more preferably 10, from the viewpoint of further efficiently disposing the solder on the electrode. Above °C.

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 further preferably 10 high, from the viewpoint of further efficiently disposing the solder on the electrode. Above °C.

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

By the melting point of the flux being higher than the melting point of the solder, the solder can be efficiently condensed on the electrode portion. The reason for this is that when heat is applied during bonding, if the electrode formed on the member to be connected is compared with the portion of the member to be connected around the electrode, the thermal conductivity of the electrode portion is higher than that of the electrode. The thermal conductivity of the portion of the component to be connected is increased, and the temperature of the electrode portion is increased. In the stage of exceeding the melting point of the solder in the conductive particles, the solder in the conductive particles is melted, but since the oxide film formed on the surface does not reach the melting point (active temperature) of the flux, it is not removed. In this state, since the temperature of the electrode portion first reaches the melting point (active temperature) of the flux, the oxide film on the surface of the solder in the conductive particles on the electrode is preferentially removed, or the surface of the solder in the conductive particles The charge is neutralized by the activated flux, whereby the solder is wetted and spread on the surface of the electrode. Thereby, the solder can be efficiently condensed on the electrode.

The content of the flux is preferably 0.5% by weight or more, and preferably 30% by weight or less, and more preferably 25% by weight or less, based on 100% by weight of the conductive material. The above conductive material may be free of flux. When the content of the flux is not less than the above lower limit and not more than the above upper limit, the oxide film is less likely to be formed on the surface of the solder and the electrode, and the oxide film formed on the surface of the solder and the electrode can be further effectively removed.

(insulating particles)

The conductive material preferably contains insulation from the viewpoint of accurately controlling the interval between the members to be connected connected by the cured material of the conductive material and the interval between the members to be connected by the solder in the conductive particles. particle. In the above conductive material, the insulating particles may not adhere to the surface of the conductive particles. In the above conductive material In the above, the insulating particles are preferably separated from the conductive particles.

The average particle diameter of the insulating particles is preferably 10 μm or more, more preferably 20 μm or more, further preferably 25 μm or more, more preferably 100 μm or less, still more preferably 75 μm or less, and still more preferably 50 μm or less. When the average particle diameter of the substrate particles is not less than the lower limit and not more than the upper limit, the interval between the members to be joined connected by the cured material of the conductive material and the interval between the members to be connected by the solder in the conductive particles Become more moderate.

Examples of the material of the insulating particles include an insulating resin and an insulating inorganic material. The resin which is exemplified as the resin for forming the resin particles which can be used as the substrate particles is exemplified as the insulating resin. The above-mentioned inorganic substance exemplified as an inorganic substance for forming inorganic particles which can be used as a substrate particle is exemplified as the insulating inorganic material.

Specific examples of the insulating resin as the material of the insulating particles include a polyolefin, a (meth) acrylate polymer, a (meth) acrylate copolymer, a block polymer, a thermoplastic resin, and a thermoplastic resin. A crosslinked product, a thermosetting resin, a water-soluble resin, or the like.

Examples of the polyolefins include polyethylene, an ethylene-vinyl acetate copolymer, and an ethylene-acrylate copolymer. Examples of the (meth) acrylate polymer include poly(methyl) acrylate, poly(ethyl) acrylate, and poly(meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylate copolymer, SB (Styrene Butadiene) type styrene-butadiene block copolymer, and SBS (Styrene). Butadiene Styrene, styrene-butadiene-styrene type styrene-butadiene block copolymer, and such hydrides and the like. Examples of the thermoplastic resin include a vinyl polymer and a vinyl copolymer. Examples of the thermosetting resin include an epoxy resin, a phenol resin, and a melamine resin. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polypropylene decylamine, and polyvinylpyrrolidine. Ketones, polyethylene oxide and methyl cellulose. It is preferably a water-soluble resin, more preferably polyvinyl alcohol.

Specific examples of the insulating inorganic material as the material of the insulating particles include cerium oxide, organic-inorganic hybrid particles, and the like. The particles formed of the cerium oxide are not particularly limited, and for example, after the crosslinked polymer particles are formed by hydrolyzing a hydrazine compound having two or more hydrolyzable alkoxyalkylene groups, The particles obtained by calcination as needed. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles obtained by crosslinking alkoxysilane alkyl polymer and an acrylic resin.

The content of the insulating particles is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and preferably 10% by weight or less, and more preferably 5% by weight or less based on 100% by weight of the conductive material. The above conductive material may not contain insulating particles. When the content of the insulating particles is not less than the above lower limit and not more than the above upper limit, the interval between the members to be joined connected by the cured material of the conductive material and the interval between the members to be connected connected by the solder in the conductive particles become more Moderate.

(carbodiimide compound)

The conductive material preferably contains a carbodiimide compound from the viewpoint of effectively improving the transparency and heat resistance of the cured product.

Examples of the above carbodiimide compound include 1,3-diisopropylcarbodiimide, bis(2,6-diisopropylphenyl)carbodiimide, and 1-ethyl- 3-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-(3-(dimethylamino)propyl)-3-ethylcarbodiimide, N, N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide a p-toluenesulfonate, a terminal isocyanate-modified polycarbodiimide compound, a cyclic carbodiimide compound, a polyisocyanate obtained by polymerizing in the presence of a carbodiimide catalyst A carbodiimide compound or the like. In terms of a larger molecular weight and less prone to outgassing, a polycarbodiimide combination is preferred. Things.

As a commercial item of the above-mentioned polycarbodiimide compound, Carbodilite V02B, Carbodilite V04K, Carbodilite V05 (both manufactured by Nisshinbo Co., Ltd.), etc. are mentioned, for example.

The content of the carbodiimide compound is preferably 0.01% by weight or more, and more preferably 0.1% by weight or more, based on 100% by weight of the conductive material, from the viewpoint of effectively improving the transparency and heat resistance of the cured product. It is preferably 5% by weight or less, more preferably 3% by weight or less.

(other ingredients)

The conductive material may contain, for example, a coupling agent, an opacifier, a reactive diluent, an antifoaming agent, a leveling agent, a filler, a bulking agent, a softening agent, a plasticizer, a polymerization catalyst, a hardening catalyst, and a coloring. Various additives such as agents, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents and flame retardants.

(Manufacturing method of connection structure and connection structure)

The connection structure of the present invention includes: a first connection target member having at least one first electrode on a surface thereof; a second connection target member having at least one second electrode on a surface thereof; and a connection portion connecting the above 1 is to connect the target member to the second connection target member. In the connection structure of the present invention, the material of the connecting portion is the conductive material. The connecting portion is a cured product of the conductive material. The connecting portion is formed of the above conductive material. In the connection structure of the present invention, the first electrode and the second electrode are electrically connected by a solder portion of the connection portion.

The method for manufacturing the connection structure includes the step of disposing the conductive material on a surface of a first connection member having at least one first electrode on the surface thereof using the conductive material, and the first conductive material and the first a step of arranging a second connection member having at least one second electrode on the surface of the surface opposite to the connection target member so that the first electrode and the second electrode face each other; and heating the conductive material to The conductive material is more than the melting point of the solder in the conductive particles, and the conductive material is used. The connection portion connecting the first connection target member and the second connection target member is formed, and the first electrode and the second electrode are electrically connected by a solder portion in the connection portion. Preferably, the conductive material is heated to a temperature higher than a curing temperature of the thermosetting component or the thermosetting compound.

In the connection structure of the present invention and the method of manufacturing the connection structure, since a specific conductive material is used, solder in the plurality of conductive particles is likely to be collected between the first electrode and the second electrode, and the solder can be used. Efficiently placed on the electrode (line). Further, it is difficult for one part of the solder to be disposed in a region (gap) where the electrode is not formed, and the amount of the solder particles disposed in the region where the electrode is not formed can be made relatively small. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. Moreover, the electrical connection between the electrodes adjacent in the lateral direction which should not be connected can be prevented, and the insulation reliability can be improved.

Further, in order to efficiently dispose the solder in the plurality of conductive particles on the electrode and to reduce the amount of solder disposed in the region where the electrode is not formed, it is preferable to use the conductive paste as the conductive material instead of Conductive film.

The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, and is preferably 100 μm or less, more preferably 80 μm or less. The solder wetted area on the surface of the electrode (the area in contact with the solder in the area where the electrode is exposed is 100%) is preferably 50% or more, more preferably 70% or more, and preferably 100% or less.

In the method of manufacturing the connection structure of the present invention, preferably, in the step of arranging the second connection member and the step of forming the connection portion, the weight of the second connection member is applied to the conductive material without performing It is preferable that the step of arranging the second connection member and the step of forming the connection portion do not apply a pressing force to the conductive material that exceeds the weight of the second connection member. In such cases, the uniformity of the amount of solder can be further improved in a plurality of solder portions. Further, the thickness of the solder portion can be further effectively increased, and the solder in the plurality of conductive particles can be easily accumulated in a large amount between the electrodes, and the solder in the plurality of conductive particles can be further efficiently disposed. On the electrode (line). Further, one of the plurality of conductive particles is less likely to be disposed in a region (gap) where the electrode is not formed, and the amount of solder disposed in the conductive particles in the region where the electrode is not formed can be further reduced. Therefore, the conduction reliability between the electrodes can be further improved. Moreover, the electrical connection between the electrodes adjacent in the lateral direction which should not be connected can be further prevented, and the insulation reliability can be further improved.

Furthermore, the inventors have found that, in the step of arranging the second connection member and the step of forming the connection portion, the weight of the second connection member is applied to the conductive material without being pressurized, and is disposed in the conductive material. The solder in which the region (gap) in which the electrode is not formed before the connection portion is formed is more likely to be collected between the first electrode and the second electrode, and the solder in the plurality of conductive particles can be more efficiently disposed on the electrode (line). . In the present invention, in order to obtain the effect of the present invention at a higher level, a combination of a conductive paste and a conductive film is used, and a weight of the second connecting member is applied to the conductive paste without applying pressure. Great sense.

Furthermore, in WO 2008/023452 A1, it is described that the solder powder is pressed and flowed to the surface of the electrode to move it efficiently, and it is possible to pressurize at a specific pressure in the subsequent step, and it is described that it is more From the viewpoint of reliably forming the solder region, the pressurizing pressure is, for example, 0 MPa or more, preferably 1 MPa or more, and further described is a member which is disposed on the tape even if the pressure applied to the tape is 0 MPa. Its own weight, put a specific pressure on the tape. Although it is described in WO 2008/023452 A1 that the pressure applied to the tape is 0 MPa, the difference between the effect of applying a pressure exceeding 0 MPa and the case of setting 0 MPa is not described. Further, in WO 2008/023452 A1, there is no knowledge about the importance of using a paste-like conductive paste instead of a film-like conductive paste.

Moreover, when a conductive paste is used instead of a conductive film, it is easy to adjust the thickness of a connection part and a solder part according to the coating amount of a conductive paste. On the other hand, regarding the conductive film, in order to change or adjust the thickness of the connection portion, it is necessary to prepare a conductive film of a different thickness, or to prepare a specific thickness. The problem of the conductive film. Further, in the conductive film, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder as compared with the conductive paste, and the solder tends to be inhibited from agglomerating.

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

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

The connection structure 1 shown in FIG. 1 includes a first connection object member 2, a second connection object member 3, and a connection portion 4 that connects the first connection object member 2 and the second connection object member 3. The connecting portion 4 is formed of the above-described conductive material. In the embodiment, the conductive material contains conductive particles and a binder. In the present embodiment, the conductive material contains solder particles as conductive particles. In the present embodiment, the binder contains a thermosetting compound and a heat curing agent. The thermosetting compound and the above-mentioned thermosetting agent are referred to as thermosetting components.

The connection portion 4 has a solder portion 4A in which a plurality of solder particles are aggregated and joined to each other, and a cured portion 4B in which a thermosetting component is thermally cured.

The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the front surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. Further, in the connection portion 4, solder is not present in a region (a portion of the cured portion 4B) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a. There is no solder separated from the solder portion 4A in a region different from the solder portion 4A (the portion of the cured portion 4B). Further, in the case of a small amount, solder may be present in a region (a portion of the cured portion 4B) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a.

As shown in FIG. 1, in the connection structure 1, a plurality of solder particles are collected on the first electrode. Between 2a and the second electrode 3a, after a plurality of solder particles are melted, the melt of the solder particles is wetted and diffused on the surface of the electrode, and then solidified to form the solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a and the solder portion 4A and the second electrode 3a is increased. In other words, by using the solder particles, the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode are used as compared with the case where the conductive portion of the metal such as nickel, gold or copper is used. The contact area of 3a increases. Therefore, the connection reliability and connection reliability of the connection structure 1 are increased.

Further, in the connection structure 1 shown in Fig. 1, all of the solder portions 4A are located in the opposing regions between the first and second electrodes 2a and 3a. The connection structure 1X of the modification shown in FIG. 3 differs from the connection structure 1 shown in FIG. 1 only in the connection portion 4X. The connecting portion 4X has a solder portion 4XA and a cured portion 4XB. As in the connection structure 1X, most of the solder portion 4XA is located in a region facing the first and second electrodes 2a and 3a, and a portion of the solder portion 4XA is opposed to the first and second electrodes 2a and 3a. The area extends to the side. The solder portion 4XA that protrudes 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 solder separated from the solder portion 4XA. Further, in the present embodiment, the amount of solder separated from the solder portion can be reduced, and the solder separated from the solder portion can be present in the cured portion.

When the amount of use of the solder particles is reduced, the connection structure 1 is easily obtained. When the amount of use of the solder particles is increased, the connection structure 1X is easily obtained.

From the viewpoint of further improving the conduction reliability, it is preferable that the first electrode 2a and the first electrode 2a and the first electrode 2a, the connection portion 4, the fourth electrode 3a and the second electrode 3a are laminated in the connection structure 1 and 1X. When the two electrodes 3a are opposed to each other, the solder portions 4A and 4XA of the connecting portions 4 and 4X are disposed at 50% or more of the area of the portion where the first electrode 2a and the second electrode 3a face each other by 100% or more. .

In view of further improving the conduction reliability, it is preferable that the first electrode and the first electrode are observed along a laminated direction of the first electrode, the connecting portion, and the second electrode. When the electrodes are opposed to each other, 50% or more (more preferably 60% or more, and still more preferably 70% or more) of the area of the portion where the first electrode and the second electrode face each other are 100% or more. More preferably, it is 80% or more, and most preferably 90% or more, and the solder portion in the above connection portion is disposed.

From the viewpoint of further improving the conduction reliability, it is preferable that the first electrode and the second electrode are opposed to each other in a direction orthogonal to a lamination direction of the first electrode, the connection portion, and the second electrode. In a portion where the first electrode and the second electrode face each other, 60% or more (more preferably 70% or more, further preferably 90% or more) of the solder portion in the connection portion is disposed. More preferably 95% or more, and most preferably 99% or more).

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

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

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

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

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

Next, the conductive material 11 is heated to a temperature equal to or higher than the melting point of the solder particles 11A (third step). It is preferable to heat the electrically conductive material 11 to the hardening temperature of the thermosetting component 11B (thermosetting compound). At the time of this heating, the solder particles 11A existing in the region where the electrode is not formed are collected between the first electrode 2a and the second electrode 3a (self-condensation effect). In the case where a conductive paste is used instead of the conductive film, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. Further, the solder particles 11A are melted and joined to each other. Further, the thermosetting component 11B is thermally cured. As a result, as shown in FIG. 2( c ), the connecting portion 4 that connects the first connection target member 2 and the second connection target member 3 is formed by the conductive material 11 . The connection portion 4 is formed by the conductive material 11, and the solder portion 4A is formed by bonding a plurality of solder particles 11A, and the cured portion 4B is formed by thermally curing the thermosetting component 11B. When the solder particles 11A are sufficiently moved, the movement of the solder particles 11A between the first electrode 2a and the second electrode 3a is completed after the movement of the solder particles 11A between the first electrode 2a and the second electrode 3a is started. Until then, the temperature can be kept constant.

In the present embodiment, in the second step and the third step, it is preferable not to pressurize. In this case, the weight of the second connection member 3 is applied to the conductive material 11. Therefore, when the connection portion 4 is formed, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. Further, in at least one of the second step and the third step, when the pressurization is performed, the tendency of the solder particles 11A to be concentrated between the first electrode 2a and the second electrode 3a is hindered. high.

In addition, in the present embodiment, when the second connection member is superposed on the first connection member to which the conductive material is applied, the electrode of the first connection member is connected to the second connection. When the first connection target member and the second connection target member are overlapped in the state in which the electrodes of the target member are offset, the offset can be corrected, and the electrode of the first connection target member and the second electrode can be corrected. The electrode connection (self-alignment effect) of the connected object member. The reason is that the electrode and the second connection are connected to the first connection target member. In the solder which is self-aggregating between the electrodes of the target member, the area where the solder between the electrode of the first connection member and the electrode of the second connection member is in contact with a component other than the conductive material is minimized in terms of energy. Since it becomes stable, the force which forms the connection structure which becomes the smallest area, ie, the structure of the alignment connection structure acts. In this case, it is preferable that the conductive material is not hardened, and at this temperature and time, the viscosity of the components other than the conductive particles of the conductive material is sufficiently low.

The connection structure 1 shown in Fig. 1 is obtained in the above manner. Furthermore, the second step and the third step described above can be continuously performed. Further, after the second step, the obtained third connection target member 2, the conductive material 11 and the second connection target member 3 may be moved to the heating unit to perform the third step. In order to perform the above heating, the laminated body may be disposed on the heating member, or the laminated body may be disposed in the heated space.

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

The heating method in the third step may be a method of heating the entire bonded structure to a temperature higher than a melting point of the solder or a hardening temperature of the thermosetting component by using a reflow furnace or using an oven; or only the connection structure A method in which the connection portion of the body is locally heated.

The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include semiconductor wafers, semiconductor packages, LED (Light Emitting Diode) wafers, LED packages, electronic components such as capacitors and diodes, and the like. Electronic components such as a resin film, a printed circuit board, a flexible printed circuit board, a flexible flat cable, a rigid flexible substrate, a glass epoxy substrate, and a glass substrate. The first and second connection target members are preferably electronic components.

At least one of the first connection target member and the second connection target member is preferably a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. Better The second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. The resin film, the flexible printed circuit board, the flexible flat cable, and the rigid flexible substrate have high flexibility and relatively lightweight properties. When a conductive film is used for the connection of such a connection member, there is a tendency that solder does not easily collect on the electrode. On the other hand, by using a conductive paste, even if a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, it is possible to sufficiently improve the conduction between the electrodes by efficiently concentrating the solder on the electrodes. Sex. When a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, it is possible to more effectively obtain reliable conduction between electrodes based on non-pressurization as compared with the case of using other connection target members such as semiconductor wafers. Sexual improvement effect.

Examples of the electrode provided in the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, a SUS electrode, and a tungsten electrode. In the case where the connection target member is a flexible printed substrate, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode or a copper electrode. In the case where the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode or a tungsten electrode. Further, in the case where the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode having an aluminum layer on a surface layer of the metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, Ga, and the like.

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

(1) having an ethylenethio group and three Synthesis of thermosetting compound A of skeleton:

To the vessel equipped with a stirrer, a cooler, and a thermometer, 1100 mL of methanol and 400 g of trimethylthiourea were added, and the first solution was prepared in a container. Thereafter, the temperature inside the vessel was maintained at 60 °C.

Next, while stirring and maintaining the first solution at 60 ° C, 600 g of TEPIC-VL (manufactured by Nissan Chemical Industries, Ltd.) and 3,600 ml of toluene were added to the first solution, and further stirred for 30 minutes to obtain a solution containing an epoxy compound. .

Next, the solution containing the epoxy compound was stirred while reacting at 60 ° C for 5 hours under a nitrogen stream. Thereafter, the solution in the vessel was transferred to a separatory funnel, allowed to stand for 2 hours, and the solution was separated. The solution below the separatory funnel was drained and the supernatant was extracted. To the extracted supernatant was added 950 mL of toluene, stirred, and allowed to stand for 2 hours.

Next, pure water was added to the supernatant containing toluene, and the mixture was repeatedly stirred and discharged to wash the solution.

Thereafter, 200 g of magnesium sulfate was added to the supernatant, and the mixture was stirred for 5 minutes. After stirring, magnesium sulfate was removed using a filter paper, and the solution was separated. The solvent remaining was removed by vacuum drying using a vacuum dryer. Obtained with an ethylenethio group and three in the above manner Thermosetting compound A of the skeleton.

The ¹ H-NMR (Nuclear Magnetic Resonance) measurement of the obtained thermosetting compound A was carried out using chloroform as a solvent. As a result, it was confirmed that the epoxy group was converted into an episulfide group.

(2) having an ethylene sulfide group and three Synthesis of thermosetting compound B of skeleton:

A TEPIC-VL (manufactured by Nissan Chemical Industries, Ltd.) was changed to TEPIC-HP (manufactured by Nissan Chemical Industries, Ltd.), and the temperature in the vessel was changed to 80 ° C, and a ring was obtained in the same manner as in the thermosetting compound A. Thioethane group and three Thermosetting compound B of the skeleton.

The ¹ H-NMR measurement of the obtained thermosetting compound B was carried out using chloroform as a solvent. As a result, it was confirmed that the epoxy group was converted into an episulfide group. The obtained thermosetting compound B had a melting point of 150 °C.

Thermosetting compound 1: epoxy compound, "EP-" manufactured by ADEKA 3300", epoxy equivalent 160g/eq

Thermosetting compound 2: epoxy compound, "TEPIC-SS" manufactured by Nissan Chemical Industries, Inc., epoxy equivalent 100g/eq

Thermosetting compound 3: epoxy compound, "TEPIC-VL" manufactured by Nissan Chemical Industries, Inc., epoxy equivalent 135 g/eq

Thermosetting agent 1: Trimethylolpropane tris(3-mercaptopropionate), "TMMP" manufactured by SC Organic Chemical Co., Ltd.

Latent epoxy heat hardener 1: "Fujicure 7000" manufactured by T & K TOKA

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

Synthesis of flux 1:

25 parts by weight of glutaric acid and 25 parts by weight of monomethyl glutarate were placed in a 3-neck flask, and dissolved at 80 ° C under a nitrogen stream. Thereafter, 57 parts by weight of benzylamine was added, and the mixture was reacted at 150 ° C for 2 hours under reduced pressure, whereby a flux 1 which was solid at 25 ° C and had a mercapto group was obtained.

Flux 2: Monomethyl glutarate, manufactured by Wako Pure Chemical Industries, Ltd.

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

Carbodilium imine compound 1: Carbodilite V02B (manufactured by Nisshinbo Co., Ltd.)

How to make solder particles 1:

Weighed SnBi solder particles ("DS-10" manufactured by Mitsui Metals Co., Ltd., average particle diameter (median diameter: 12 μm)), 200 g, and a cyanide coupling agent having an isocyanate group ("KBE-9007" manufactured by Shin-Etsu Silicones Co., Ltd.) 20 g and 70 g of acetone were placed in a 3-neck flask. While stirring at room temperature, 0.25 g of dibutyltin laurate as a reaction catalyst of a hydroxyl group and an isocyanate group on the surface of the solder particles was added, and the mixture was stirred at 100 ° C under a nitrogen atmosphere. Heat for 2 hours. Thereafter, 120 g of methanol and 0.05 g of acetic acid were added, and the mixture was heated at 60 ° C for 1 hour under stirring in a nitrogen atmosphere.

Thereafter, the mixture was cooled to room temperature, and the solder particles were filtered by a filter paper, and desolventized by vacuum drying at room temperature for 1 hour to obtain solder particles.

The above solder particles were placed in a 3-necked flask, and 45 g of acetone, 40 g of monoethyl adipate, and pentafluorobenzenesulfonic acid were added. 0.2 g of the ammonium chloride was reacted under stirring at 65 ° C for 1 hour under a nitrogen atmosphere, and then vacuum-dried to carry out solvent removal.

Thereafter, the solder particles were placed in a 3-necked flask, and 85 g of acetone, 40 g of adipic acid, and 0.5 g of isopropyl isopropoxide were added, and the mixture was reacted at 65 ° C for 1 hour, and then cooled to room temperature to obtain a filter paper. The solder particles were filtered, and the solder particles were washed twice with acetone on a filter paper, washed once with hexane, and then desolventized by vacuum drying at room temperature for 1 hour.

After the obtained solder particles are crushed by a ball mill, the sieve is selected so as to have a specific CV value.

Thereby, the solder particles 1 are obtained. Regarding the obtained solder particles 1, the CV value was 20%, and the acid value was 0.5 mg/KOH.

How to make solder particles 2:

The solder particles 2 were produced in the same manner as the solder particles 1 except that the solder particles were washed once with hexane on the filter paper. Regarding the obtained solder particles 2, the CV value was 20%, and the acid value was 13 mg/KOH.

Solder particles A (SnBi solder particles, melting point 139 ° C, "DS-10" manufactured by Mitsui Metals Co., Ltd., average particle diameter (median diameter: 12 μm)), acid value: 0.2 mg / KOH

(CV value of solder particles)

The CV value was measured by a laser diffraction type particle size distribution measuring apparatus ("LA-920" manufactured by Horiba, Ltd.).

(acid value of solder particles)

To the ethanol, phenolphthalein was added, and 50 g of a solution neutralized with 0.1 N-KOH was added, and 1 g of conductive particles (solder particles) was added, and the mixture was dispersed by ultrasonic treatment, and then titrated with 0.1 N-KOH. Acid value.

(Examples 1 to 5 and Comparative Examples 1 to 3)

(1) Production of anisotropic conductive paste

The components shown in the following Table 1 were blended in the amounts shown in Table 1 below to obtain an anisotropic conductive paste.

The connection structure was produced in the following manner.

(2) Production of connection structure (L/S = 75 μm / 75 μm)

A glass epoxy substrate (FR-4 substrate, thickness: 0.6 mm) having a copper electrode pattern (having a thickness of 12 μm of a copper electrode) having an L/S of 75 μm/75 μm and an electrode length of 3 mm was prepared on the upper surface (first connection target member). Further, a flexible printed circuit board having a copper electrode pattern (thickness of a copper electrode of 12 μm) having an L/S of 75 μm/75 μm and an electrode length of 3 mm on the lower surface (a second connection member formed of polyimine) and having a thickness of 0.1 is prepared. Mm).

The overlapping area of the glass epoxy substrate and the flexible printed substrate was set to 1.5 cm × 3 mm, and the number of connected electrodes was set to 75 pairs.

On the upper surface of the glass epoxy substrate, the anisotropic conductive paste immediately after the application was applied to the electrode of the glass epoxy substrate so as to have a thickness of 100 μm to form an anisotropic conductive paste layer. Next, the flexible printed circuit board is laminated on the upper surface of the anisotropic conductive paste layer so that the electrodes face each other, and the heating head is placed on the upper surface of the flexible printed circuit board, and the temperature is raised from room temperature to 180 ° C to make the lateral direction. The solder particles between the electrodes are agglomerated, and the solder particles are agglomerated and melted between the upper and lower electrodes, and further heated at 180 ° C for 10 seconds to cure the anisotropic conductive paste layer to obtain a bonded structure. At this time, the pressure of the above-mentioned flexible printed circuit board and the degree to which the flexible printed circuit board does not warp are applied to the anisotropic conductive paste layer.

(Evaluation)

(1) Viscosity

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

(2) preservation stability

The anisotropic conductive paste was stored at 23 ° C for 24 hours. After storage, the viscosity (η25) of the anisotropic conductive paste at 25 ° C was measured at 25 ° C and 5 rpm using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.). The storage stability was determined by the following criteria.

[Criteria for the determination of preservation stability]

○○: Viscosity after storage/viscosity before storage is less than 1.2 times

○: Viscosity after storage/viscosity before storage is 1.2 times or more and less than 1.5 times

△: viscosity after storage/viscosity before storage is 1.5 times or more and less than 2 times

×: viscosity after storage/viscosity before storage is 2 times or more

(3) Outflow prevention of components other than conductive particles

In the obtained connection structure, the length of the portion protruding from the electrode was observed and measured by a microscope, and the outflow prevention property of the components other than the conductive particles was evaluated. The outflow prevention property of the components other than the conductive particles was determined by the following criteria.

[Criteria for determining the outflow prevention of components other than conductive particles]

○○: The length of the portion protruding from the electrode is less than 150 μm.

○: The length of the portion protruding from the electrode is 150 μm or more and less than 200 μm.

△: The length of the portion protruding from the electrode is 200 μm or more and less than 300 μm.

×: The length of the portion protruding from the electrode is 300 μm or more

(4) Thickness of the solder portion

By taking a cross-sectional view of the obtained connected structure, the electricity is located above and below The thickness of the solder portion between the electrodes was evaluated.

(5) Configuration accuracy of the solder on the electrode 1

In the obtained connection structure, when the first electrode and the second electrode face each other in the direction of lamination of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode are mutually The ratio X of the area of the solder portion in the connection portion among the 100% of the area of the portion was evaluated. The arrangement accuracy 1 of the solder on the electrode was determined by the following reference.

[Criteria for determining the placement accuracy of solder on the electrode 1]

○○: ratio X is 70% or more

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

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

×: The ratio X is less than 50%

(6) Placement accuracy of the solder on the electrode 2

In the connection structure obtained, when the first electrode and the second electrode face each other in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, the connection portion is formed in the connection portion. In the solder portion 100%, the ratio Y of the solder portions in the connection portions of the first electrode and the second electrode facing each other is evaluated. The arrangement accuracy 2 of the solder on the electrode is determined by the following reference.

[Criteria for determining the placement accuracy of solder on the electrode 2]

○○: ratio Y is 99% or more

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

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

×: The ratio Y is less than 70%

(7) Continuity reliability between the upper and lower electrodes

In the obtained connection structures (n = 15), the connection resistance of each connection portion between the upper and lower electrodes was measured by a 4-terminal method. Calculate the average of the connection resistance value. Furthermore, the connection resistance can be obtained by measuring the voltage at the time of flowing a fixed current based on the relationship of voltage=current×resistance. The conduction reliability is determined by the following criteria.

[Determination of Conductivity Reliability]

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

○: The average value of the 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 100mΩ, or a connection failure occurs.

(8) Insulation reliability between electrodes adjacent in the lateral direction

After allowing to stand in an environment of 85 ° C and a humidity of 85% for 100 hours in the obtained connection structure (n = 15 pieces), 15 V was applied between the electrodes adjacent in the lateral direction, and the resistance value was measured at 25 points. The insulation reliability was determined by the following criteria.

[Determination of insulation reliability]

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

○○: The average value of the connection resistance is 10 ⁸ Ω or more and less than 10 ¹⁴ Ω

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

△: The average value of the connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω.

×: The average value of the connection resistance is less than 10 ⁵ Ω

(9) Positional shift between the upper and lower electrodes

In the obtained connection structure, when the first electrode and the second electrode are opposed to each other along the laminated direction of the first electrode, the connection portion, and the second electrode, the center line and the second electrode of the first electrode are evaluated. Whether the center line of the electrode is consistent and the distance of the positional offset. The positional shift between the upper and lower electrodes is determined by the following reference.

[Criteria for determining the positional shift between the upper and lower electrodes]

○○: Position offset is less than 15μm

○: The positional shift is 15 μm or more and less than 25 μm.

△: The positional shift is 25 μm or more and less than 40 μm.

×: The positional shift is 40 μm or more

(10) Heat resistance (heat resistant yellowing)

Among the blending components shown in the following Table 1, a formulation in which a component other than the solder particles in the conductive paste was prepared was prepared to prepare a cured sheet having a thickness of 0.6 mm. After storage at 150 ° C for 2,000 hours, the transmittance at a measurement wavelength of 400 nm was measured to evaluate heat resistance (heat-resistant yellowing). The heat resistance was determined by the following criteria.

[Criteria for determination of heat resistance]

○○: The transmittance after storage at high temperature is 93% or more

○: The transmittance after storage at high temperature is 90% or more and less than 93%.

△: The transmittance after storage at high temperature is 87% or more and less than 90%.

×: does not meet the criteria of ○○, ○, and △

The results are shown in Table 1 below.

The same tendency can be seen when a resin film, a flexible flat cable, and a rigid flexible substrate are used instead of the flexible printed substrate.

1‧‧‧Connection structure

2‧‧‧1st connection object component

2a‧‧‧1st electrode

3‧‧‧2nd connection object component

3a‧‧‧2nd electrode

4‧‧‧Connecting Department

4A‧‧‧ solder department

4B‧‧‧ Hardened Parts

Claims (15)

A conductive material comprising: a plurality of conductive particles having a solder on a surface portion of a conductive portion, a thermosetting compound, and a heat hardening agent, wherein the thermosetting compound comprises an ethylene sulfide group and three A thermosetting compound of the skeleton. The conductive material of claim 1, wherein the above has an ethylene sulfide group and three The melting point of the thermosetting compound of the skeleton is 140 ° C or higher. The conductive material of claim 1 or 2, which comprises a different from the group having an ethylene sulfide group and three A thermosetting compound of a thermosetting compound of a skeleton. The conductive material according to claim 1 or 2, wherein the conductive particles have an acid value of 0.1 mg/KOH or more and 10 mg/KOH or less. A conductive material according to claim 1 or 2, which comprises a flux. The conductive material of claim 5, wherein the flux is a flux having a mercaptoamine group and an aromatic skeleton, or a compound having a mercaptoamine group and being a carboxylic acid or a carboxylic acid anhydride and an amine group having a pKa of 9.5 or less. The flux of the reactants. The conductive material of claim 5, wherein the flux is solid at 25 °C. A conductive material according to claim 1 or 2, which comprises a carbodiimide compound. The conductive material of claim 1 or 2, wherein the conductive particles are solder particles. The conductive material according to claim 1 or 2, which comprises insulating particles not attached 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 of claim 1 or 2, wherein the conductive material is 100% by weight, the above The content of the conductive particles is 10% by weight or more and 80% by weight or less. The conductive material of claim 1 or 2, which is liquid at 25 ° C and is a conductive paste. A connection structure comprising: a first connection target member having at least one first electrode on a surface thereof; a second connection target member having at least one second electrode on a surface thereof; and a connection portion connecting the above a connection target member and the second connection target member; wherein the connection portion is made of a conductive material according to any one of claims 1 to 13, wherein the first electrode and the second electrode are soldered by the connection portion Department and electrical connection. The connection structure according to claim 14, wherein the first electrode and the second electrode are opposed to each other along a direction of lamination of the first electrode, the connection portion, and the second electrode, and the first The solder portion in the connection portion is disposed at 50% or more of the area of the portion where the electrode and the second electrode face each other.